draft-ietf-webdav-acl-07.txt   draft-ietf-webdav-acl-08.txt 
INTERNET-DRAFT Geoffrey Clemm, Rational Software INTERNET-DRAFT Geoffrey Clemm, Rational Software
draft-ietf-webdav-acl-07 Anne Hopkins, Microsoft Corporation draft-ietf-webdav-acl-08 Anne Hopkins, Microsoft Corporation
Eric Sedlar, Oracle Corporation Eric Sedlar, Oracle Corporation
Jim Whitehead, U.C. Santa Cruz Jim Whitehead, U.C. Santa Cruz
Expires May 9, 2001 November 9, 2001 Expires November 7, 2002 May 7, 2002
WebDAV Access Control Protocol WebDAV Access Control Protocol
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with all This document is an Internet-Draft and is in full conformance with
provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Task
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may also distribute working documents as Internet-Drafts.
Internet-Drafts are working documents of the Internet Engineering
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Abstract Abstract
This document specifies a set of methods, headers, and message bodies This document specifies a set of methods, headers, and message bodies
that define Access Control extensions to the WebDAV Distributed that define Access Control extensions to the WebDAV Distributed
Authoring Protocol. This protocol permits a client to read and modify Authoring Protocol. This protocol permits a client to read and modify
access control lists that instruct a server whether to allow or deny access control lists that instruct a server whether to allow or deny
operations upon a resource (such as HTTP method invocations) by a given operations upon a resource (such as HTTP method invocations) by a
principal. given principal.
This document is a product of the Web Distributed Authoring and This document is a product of the Web Distributed Authoring and
Versioning (WebDAV) working group of the Internet Engineering Task Versioning (WebDAV) working group of the Internet Engineering Task
Force. Comments on this draft are welcomed, and should be addressed to Force. Comments on this draft are welcomed, and should be addressed
the acl@webdav.org mailing list. Other related documents can be found at to the acl@webdav.org mailing list. Other related documents can be
http://www.webdav.org/acl/, and http://www.ics.uci.edu/pub/ietf/webdav/. found at http://www.webdav.org/acl/, and
http://www.ics.uci.edu/pub/ietf/webdav/.
Clemm, Hopkins, Sedlar, Whitehead [Page 1] Clemm, Hopkins, Sedlar, Whitehead [Page 1]
Table of Contents Table of Contents
1 INTRODUCTION.......................................................5 1 INTRODUCTION...................................................4
1.1 Terms............................................................7 1.1 Terms........................................................7
1.2 Notational Conventions...........................................8 1.2 Notational Conventions.......................................8
2 PRINCIPALS.........................................................8 2 PRINCIPALS.....................................................8
3 PRIVILEGES.........................................................9 3 PRIVILEGES.....................................................9
3.1 DAV:read Privilege..............................................11 3.1 DAV:read Privilege...........................................10
3.2 DAV:write Privilege.............................................11 3.2 DAV:write Privilege..........................................10
3.3 DAV:read-acl Privilege..........................................11 3.3 DAV:write-properties.........................................11
3.4 DAV:read-current-user-privilege-set Privilege...................11 3.4 DAV:write-content............................................11
3.5 DAV:write-acl Privilege.........................................12 3.5 DAV:unlock...................................................11
3.6 DAV:all Privilege...............................................12 3.6 DAV:read-acl Privilege.......................................12
3.7 Aggregation of Predefined Privileges............................12 3.7 DAV:read-current-user-privilege-set Privilege................12
3.8 DAV:write-acl Privilege......................................12
3.9 DAV:all Privilege............................................12
3.10 Aggregation of Predefined Privileges........................12
4 PRINCIPAL PROPERTIES..............................................12 4 PRINCIPAL PROPERTIES...........................................13
4.1 DAV:alternate-URI-set...........................................13 4.1 DAV:alternate-URI-set........................................13
4.2 DAV:principal-URL............................................14
4.3 DAV:group-membership.........................................14
5 ACCESS CONTROL PROPERTIES.........................................13 5 ACCESS CONTROL PROPERTIES......................................14
5.1 DAV:owner.......................................................13 5.1 DAV:owner....................................................14
5.1.1 Example: Retrieving DAV:owner................................14 5.1.1 Example: Retrieving DAV:owner............................15
5.1.2 Example: An Attempt to Set DAV:owner.........................15 5.1.2 Example: An Attempt to Set DAV:owner.....................16
5.2 DAV:supported-privilege-set.....................................16 5.2 DAV:supported-privilege-set..................................17
5.2.1 Example: Retrieving a List of Privileges Supported on a 5.2.1 Example: Retrieving a List of Privileges Supported on a
Resource.....................................................16 Resource.......................................................18
5.3 DAV:current-user-privilege-set..................................18 5.3 DAV:current-user-privilege-set...............................20
5.3.1 Example: Retrieving the User's Current Set of Assigned 5.3.1 Example: Retrieving the User's Current Set of Assigned
Privileges.........................................................19 Privileges.....................................................21
5.4 DAV:acl.........................................................20 5.4 DAV:acl......................................................22
5.4.1 ACE Principal................................................20 5.4.1 ACE Principal............................................22
5.4.2 ACE Grant and Deny...........................................21 5.4.2 ACE Grant and Deny.......................................23
5.4.3 ACE Protection...............................................21 5.4.3 ACE Protection...........................................24
5.4.4 ACE Inheritance..............................................22 5.4.4 ACE Inheritance..........................................24
5.4.5 Example: Retrieving a Resource's Access Control List......22 5.4.5 Example: Retrieving a Resource's Access Control List.....24
5.5 DAV:acl-semantics...............................................23 5.5 DAV:inherited-acl............................................26
5.5.1 Example: Retrieving DAV:acl-semantics........................24 5.6 DAV:acl-semantics............................................26
5.6 DAV:principal-collection-set....................................25 5.6.1 Example: Retrieving DAV:acl-semantics....................26
5.6.1 Example: Retrieving DAV:principal-collection-set.............26 5.7 DAV:principal-collection-set.................................28
5.7 Example: PROPFIND to retrieve access control properties.........27 5.7.1 Example: Retrieving DAV:principal-collection-set.........29
5.8 Example: PROPFIND to retrieve access control properties......30
6 ACL SEMANTICS.....................................................30
6.1 ACE Combination.................................................31
6.1.1 DAV:first-match ACE Combination..............................31
6.1.2 DAV:all-grant-before-any-deny ACE Combination................31
6.1.3 DAV:specific-deny-overrides-grant ACE Combination............31
6.2 ACE Ordering....................................................31
6.2.1 DAV:deny-before-grant ACE Ordering...........................32
6.3 Allowed ACE.....................................................32
6.3.1 DAV:principal-only-one-ace ACE Constraint....................32
Clemm, Hopkins, Sedlar, Whitehead [Page 2] Clemm, Hopkins, Sedlar, Whitehead [Page 2]
6.3.2 DAV:grant-only ACE Constraint................................32 6 ACL SEMANTICS.................................................34
6.4 Required Principals.............................................32 6.1 ACE Combination.............................................34
6.1.1 DAV:first-match ACE Combination.........................34
6.1.2 DAV:all-grant-before-any-deny ACE Combination...........34
6.1.3 DAV:specific-deny-overrides-grant ACE Combination.......34
6.2 ACE Ordering................................................35
6.2.1 DAV:deny-before-grant ACE Ordering......................35
6.3 Allowed ACE.................................................35
6.3.1 DAV:principal-only-one-ace ACE Constraint...............35
6.3.2 DAV:grant-only ACE Constraint...........................35
6.3.3 DAV:no-invert ACE Constraint............................35
6.3.4 DAV:no-acl-inherit ACE Constraint.......................36
6.4 Required Principals.........................................36
7 ACCESS CONTROL AND EXISTING METHODS...............................32 7 ACCESS CONTROL AND EXISTING METHODS...........................36
7.1 OPTIONS.........................................................33 7.1 OPTIONS.....................................................36
7.1.1 Example - OPTIONS............................................33 7.1.1 Example - OPTIONS.......................................36
7.2 MOVE............................................................33 7.2 MOVE........................................................37
7.3 COPY............................................................33 7.3 COPY........................................................37
7.4 DELETE..........................................................33 7.4 DELETE......................................................37
7.5 LOCK............................................................34 7.5 LOCK........................................................37
8 ACCESS CONTROL METHODS............................................34 8 ACCESS CONTROL METHODS........................................37
8.1 ACL.............................................................34 8.1 ACL.........................................................37
8.1.1 ACL Preconditions............................................34 8.1.1 ACL Preconditions.......................................38
8.1.2 Example: the ACL method......................................36 8.1.2 Example: the ACL method.................................40
8.1.3 Example: ACL method failure due to protected ACE conflict....37 8.1.3 Example: ACL method failure due to protected ACE conflict
8.1.4 Example: ACL method failure due to an inherited ACE conflict 38 .....41
8.1.4 Example: ACL method failure due to an inherited ACE conflict
.....42
8.1.5 Example: ACL method failure due to an attempt to set grant 8.1.5 Example: ACL method failure due to an attempt to set grant
and deny in a single ACE.....................................39 and deny in a single ACE......................................43
9 ACCESS CONTROL REPORTS............................................40 9 ACCESS CONTROL REPORTS........................................44
9.1 REPORT Method...................................................40 9.1 REPORT Method...............................................44
9.2 DAV:acl-principal-props Report..................................40 9.2 DAV:acl-principal-prop-set Report...........................44
9.2.1 Example: DAV:acl-principal-props Report......................40 9.2.1 Example: DAV:acl-principal-prop-set Report..............45
9.3 DAV:principal-match REPORT......................................42 9.3 DAV:principal-match REPORT..................................46
9.3.1 Example: DAV:principal-match REPORT..........................43 9.3.1 Example: DAV:principal-match REPORT.....................47
9.4 DAV:principal-property-search REPORT............................44 9.4 DAV:principal-property-search REPORT........................48
9.4.1 Matching.....................................................45 9.4.1 Matching................................................50
9.4.2 Example: successful DAV:principal-property-search REPORT.....46 9.4.2 Example: successful DAV:principal-property-search REPORT
9.4.3 Example: Unsuccessful DAV:principal-property-search REPORT...48 .....51
9.5 DAV:principal-search-property-set REPORT........................49 9.4.3 Example: Unsuccessful DAV:principal-property-search REPORT
9.5.1 Example: DAV:principal-search-property-set REPORT............50 .....53
9.5 DAV:principal-search-property-set REPORT....................54
9.5.1 Example: DAV:principal-search-property-set REPORT.......55
10 XML PROCESSING..................................................51 10 XML PROCESSING..............................................56
11 INTERNATIONALIZATION CONSIDERATIONS.............................51 11 INTERNATIONALIZATION CONSIDERATIONS.........................56
12 SECURITY CONSIDERATIONS.........................................52 Clemm, Hopkins, Sedlar, Whitehead [Page 3]
12.1 Increased Risk of Compromised Users...........................52 12 SECURITY CONSIDERATIONS......................................57
12.1 Increased Risk of Compromised Users.........................57
12.2 Risks of the DAV:read-acl and DAV:current-user-privilege-set 12.2 Risks of the DAV:read-acl and DAV:current-user-privilege-set
Privileges....................................................52 Privileges.......................................................57
12.3 No Foreknowledge of Initial ACL...............................53 12.3 No Foreknowledge of Initial ACL.............................58
13 AUTHENTICATION..................................................53
14 IANA CONSIDERATIONS.............................................53
15 INTELLECTUAL PROPERTY...........................................54
16 ACKNOWLEDGEMENTS................................................54 13 AUTHENTICATION...............................................58
Clemm, Hopkins, Sedlar, Whitehead [Page 3] 14 IANA CONSIDERATIONS..........................................59
17 REFERENCES......................................................55 15 INTELLECTUAL PROPERTY........................................59
17.1 Normative References..........................................55
17.2 Informational References......................................56
18 AUTHORS' ADDRESSES..............................................56 16 ACKNOWLEDGEMENTS.............................................59
19 APPENDICIES.....................................................57 17 REFERENCES...................................................60
19.1 XML Document Type Definition..................................57 17.1 Normative References........................................60
17.2 Informational References....................................61
20 NOTE TO RFC EDITOR..............................................59 18 AUTHORS' ADDRESSES...........................................61
Clemm, Hopkins, Sedlar, Whitehead [Page 4] 19 APPENDICES...................................................62
19.1 WebDAV XML Document Type Definition Addendum................62
1 INTRODUCTION 1 INTRODUCTION
The goal of the WebDAV access control extensions is to provide an The goal of the WebDAV access control extensions is to provide an
interoperable mechanism for handling discretionary access control for interoperable mechanism for handling discretionary access control
content and metadata managed by WebDAV servers. WebDAV access for content and metadata managed by WebDAV servers. WebDAV access
control can be implemented on content repositories with security as control can be implemented on content repositories with security as
simple as that of a UNIX file system, as well as more sophisticated simple as that of a UNIX file system, as well as more sophisticated
models. The underlying principle of access control is that who you models. The underlying principle of access control is that who you
are determines what operations you can perform on a resource. The are determines what operations you can perform on a resource. The
"who you are" is defined by a "principal" identifier; users, client "who you are" is defined by a "principal" identifier; users, client
software, servers, and groups of the previous have principal software, servers, and groups of the previous have principal
identifiers. The "operations you can perform" is determined by a identifiers. The "operations you can perform" are determined by a
single "access control list" (ACL) associated with a resource. An single "access control list" (ACL) associated with a resource. An
ACL contains a set of "access control entries" (ACEs), where each ACE ACL contains a set of "access control entries" (ACEs), where each
specifies a principal and a set of privileges that are either granted ACE specifies a principal and a set of privileges that are either
or denied to that principal. When a principal submits an operation granted or denied to that principal. When a principal submits an
(such as an HTTP or WebDAV method) to a resource for execution, the operation (such as an HTTP or WebDAV method) to a resource for
server evaluates the ACEs in the ACL to determine if the principal execution, the server evaluates the ACEs in the ACL to determine if
has permission for that operation. the principal has permission for that operation.
Since every ACE contains the identifier of a principal, client Since every ACE contains the identifier of a principal, client
software operated by a human must provide a mechanism for selecting software operated by a human must provide a mechanism for selecting
this principal. This specification uses http(s) scheme URLs to this principal. This specification uses http(s) scheme URLs to
identify principals, which are represented as WebDAV-capable identify principals, which are represented as WebDAV-capable
resources. There is no guarantee that the URLs identifying principals
will be meaningful to a human. For example, Clemm, Hopkins, Sedlar, Whitehead [Page 4]
http://www.dav.org/u/256432 and http://www.dav.org/people/Greg.Stein resources. There is no guarantee that the URLs identifying
are both valid URLs that could be used to identify the same principals will be meaningful to a human. For example,
principal. To remedy this, every principal resource has the http://www.dav.org/u/256432 and
DAV:displayname property containing a human-readable name for the http://www.dav.org/people/Greg.Stein are both valid URLs that could
principal. be used to identify the same principal. To remedy this, every
principal resource has the DAV:displayname property containing a
human-readable name for the principal.
Since a principal can be identified by multiple URLs, it raises the Since a principal can be identified by multiple URLs, it raises the
problem of determining exactly which principal's operations are being problem of determining exactly which principal's operations are
described in a given ACE. It is impossible for a client to determine being described in a given ACE. It is impossible for a client to
that an ACE granting the read privilege to determine that an ACE granting the read privilege to
http://www.dav.org/people/Greg.Stein also affects the principal at http://www.dav.org/people/Greg.Stein also affects the principal at
http://www.dav.org/u/256432. That is, a client has no mechanism for http://www.dav.org/u/256432. That is, a client has no mechanism for
determining that two URLs identify the same principal resource. As a determining that two URLs identify the same principal resource. As
result, this specification requires clients to use just one of the a result, this specification requires clients to use just one of
many possible URLs for a principal when creating ACEs. A client can the many possible URLs for a principal when creating ACEs. A client
discover this URL by retrieving the DAV:principal-URL property can discover which URL to use by retrieving the DAV:principal-URL
(Section 4.2) from a principal resource. No matter which of the property (Section 4.2) from a principal resource. No matter which
principal's URLs is used with PROPFIND, the property always returns of the principal's URLs is used with PROPFIND, the property always
the same URL. returns the same URL.
Once a system has hundreds to thousands of principals, the problem Once a system has hundreds to thousands of principals, the problem
arises of how to allow a human operator of client software to select arises of how to allow a human operator of client software to
just one of these principals. One approach is to use broad collection select just one of these principals. One approach is to use broad
collection hierarchies to spread the principals over a large number
Clemm, Hopkins, Sedlar, Whitehead [Page 5] of collections, yielding few principals per collection. An example
hierarchies to spread the principals over a large number of of this is a two level hierarchy with the first level containing 36
collections, yielding few principals per collection. An example of
this is a two level hierarchy with the first level containing 36
collections (a-z, 0-9), and the second level being another 36, collections (a-z, 0-9), and the second level being another 36,
creating collections /a/a/, /a/b/, Ó, /a/z/, such that a principal creating collections /a/a/, /a/b/, ..., /a/z/, such that a
with last name "Stein" would appear at /s/t/Stein. In effect, this principal with last name "Stein" would appear at /s/t/Stein. In
pre-computes a common query, search on last name, and encodes it into effect, this pre-computes a common query, search on last name, and
a hierarchy. The drawback with this scheme is that it handles only a encodes it into a hierarchy. The drawback with this scheme is that
small set of predefined queries, and drilling down through the it handles only a small set of predefined queries, and drilling
collection hierarchy adds unnecessary steps (navigate down/up) when down through the collection hierarchy adds unnecessary steps
the user already knows the principal's name. While organizing (navigate down/up) when the user already knows the principal's
principal URLs into a hierarchy is a valid namespace organization, name. While organizing principal URLs into a hierarchy is a valid
users should not be forced to navigate this hierarchy to select a namespace organization, users should not be forced to navigate this
principal. hierarchy to select a principal.
This specification provides the capability to perform substring This specification provides the capability to perform substring
searches on a small set of properties on the resources representing searches on a small set of properties on the resources representing
principals. This permits searches based on last name, first name, principals. This permits searches based on last name, first name,
user name, job title, etc. Two separate searches are supported, via user name, job title, etc. Two separate searches are supported,
the REPORT method, one to search principal resources, the other to both via the REPORT method, one to search principal resources, the
determine which properties may be searched at all. other to determine which properties may be searched at all.
Clemm, Hopkins, Sedlar, Whitehead [Page 5]
Once a principal has been identified in an ACE, a server evaluating Once a principal has been identified in an ACE, a server evaluating
that ACE must know the identity of the principal making a protocol that ACE must know the identity of the principal making a protocol
request, and must validate that that principal is who they claim to request, and must validate that that principal is who they claim to
be, a process known as authentication. This specification be, a process known as authentication. This specification
intentionally omits discussion of authentication, as the HTTP intentionally omits discussion of authentication, as the HTTP
protocol already has a number of authentication mechanisms [RFC2617]. protocol already has a number of authentication mechanisms
Some authentication mechanism (such as HTTP Digest Authentication, [RFC2617]. Some authentication mechanism (such as HTTP Digest
which all WebDAV compliant implementations are required to support) Authentication, which all WebDAV compliant implementations are
must be available to validate the identity of a principal. required to support) must be available to validate the identity of
a principal.
The following issues are out of scope for this document: The following issues are out of scope for this document:
* Access control that applies only to a particular property on a * Access control that applies only to a particular property
resource (excepting the access control properties DAV:acl and on a resource (excepting the access control properties
DAV:current-user-privilege-set), rather than the entire DAV:acl and DAV:current-user-privilege-set), rather than
resource, the entire resource,
* Role-based security (where a role can be seen as a dynamically * Role-based security (where a role can be seen as a
defined collection of principals), dynamically defined group of principals),
* Specification of the ways an ACL on a resource is initialized, * Specification of the ways an ACL on a resource is
initialized,
* Specification of an ACL that applies globally to all * Specification of an ACL that applies globally to all
resources, rather than to a particular resource. resources, rather than to a particular resource.
* Creation and maintenance of resources representing people or * Creation and maintenance of resources representing people
computational agents (principals), and groups of these. or computational agents (principals), and groups of these.
This specification is organized as follows. Section 1.1 defines key This specification is organized as follows. Section 1.1 defines key
concepts used throughout the specification, and is followed by a more concepts used throughout the specification, and is followed by a
more in-depth discussion of principals (Section 2), and privileges
Clemm, Hopkins, Sedlar, Whitehead [Page 6]
in-depth discussion of principals (Section 2), and privileges
(Section 3). Properties defined on principals are specified in (Section 3). Properties defined on principals are specified in
Section 4, and access control properties for content resources are Section 4, and access control properties for content resources are
specified in Section 5. The semantics of access control lists are specified in Section 5. The semantics of access control lists are
described in Section 6, including sections on ACE combination described in Section 6, including sections on ACE combination
(Section 6.1), ACE ordering (Section 6.2), and principals required to (Section 6.1), ACE ordering (Section 6.2), and principals required
be present in an ACE (Section 6.4). Client discovery of access to be present in an ACE (Section 6.3.2). Client discovery of access
control capability using OPTIONS is described in Section 7.1. control capability using OPTIONS is described in Section 7.1.
Interactions between access control functionality and existing HTTP Interactions between access control functionality and existing HTTP
and WebDAV methods are described in the remainder of Section 7. The and WebDAV methods are described in the remainder of Section 7. The
access control setting method, ACL, is specified in Section 8. Four access control setting method, ACL, is specified in Section 8. Four
reports that provide limited server-side searching capabilities are reports that provide limited server-side searching capabilities are
described in Section 9. A note on XML processing (Section 10), described in Section 9. Sections on XML processing (Section 10),
Internationalization considerations (Section 11), security Internationalization considerations (Section 11), security
considerations (Section 12), and a note on authentication (Section considerations (Section 12), and authentication (Section 13) round
13) round out the specification. An appendix (Section 19.1) provides out the specification. An appendix (Section 19.1) provides an XML
an XML Document Type Definition (DTD) for the XML elements defined in
the specification. Clemm, Hopkins, Sedlar, Whitehead [Page 6]
Document Type Definition (DTD) for the XML elements defined in the
specification.
1.1 Terms 1.1 Terms
This draft uses the terms defined in HTTP [RFC2616] and WebDAV This draft uses the terms defined in HTTP [RFC2616] and WebDAV
[RFC2518]. In addition, the following terms are defined: [RFC2518]. In addition, the following terms are defined:
principal principal
A "principal" is a distinct human or computational actor that A "principal" is a distinct human or computational actor that
initiates access to network resources. In this protocol, a initiates access to network resources. In this protocol, a
principal is an HTTP resource that represents such an actor. principal is an HTTP resource that represents such an actor.
principal collection group
A "group" is a principal that represents a set of other principals.
A "principal collection" is a group of principals, and is
represented in this protocol by a WebDAV collection containing HTTP
resources that represent principals, and principal collections.
privilege privilege
A "privilege" controls access to a particular set of HTTP A "privilege" controls access to a particular set of HTTP
operations on a resource. operations on a resource.
aggregate privilege aggregate privilege
An "aggregate privilege" is a privilege that contains a set of An "aggregate privilege" is a privilege that contains a set of
other privileges. other privileges.
abstract privilege abstract privilege
The modifier "abstract", when applied to a privilege, means the The modifier "abstract", when applied to a privilege, means the
privilege cannot be set in an access control element (ACE). privilege cannot be set in an access control element (ACE).
access control list (ACL) access control list (ACL)
Clemm, Hopkins, Sedlar, Whitehead [Page 7]
An "ACL" is a list of access control elements that define access An "ACL" is a list of access control elements that define access
control to a particular resource. control to a particular resource.
access control element (ACE) access control element (ACE)
An "ACE" either grants or denies a particular set of (non-abstract) An "ACE" either grants or denies a particular set of (non-abstract)
privileges for a particular principal. privileges for a particular principal.
inherited ACE inherited ACE
An "inherited ACE" is an ACE that is dynamically shared from the An "inherited ACE" is an ACE that is dynamically shared from the
ACL of another resource. When a shared ACE changes on the primary ACL of another resource. When a shared ACE changes on the primary
resource, it is also changed on inheriting resources. resource, it is also changed on inheriting resources.
protected property protected property
A "protected property" is one whose value cannot be updated except A "protected property" is one whose value cannot be updated except
by a method explicitly defined as updating that specific property. by a method explicitly defined as updating that specific property.
Clemm, Hopkins, Sedlar, Whitehead [Page 7]
In particular, a protected property cannot be updated with a In particular, a protected property cannot be updated with a
PROPPATCH request. PROPPATCH request.
1.2 Notational Conventions 1.2 Notational Conventions
The augmented BNF used by this document to describe protocol elements The augmented BNF used by this document to describe protocol
is described in Section 2.1 of [RFC2616]. Because this augmented BNF elements is described in Section 2.1 of [RFC2616]. Because this
uses the basic production rules provided in Section 2.2 of [RFC2616], augmented BNF uses the basic production rules provided in Section
those rules apply to this document as well. 2.2 of [RFC2616], those rules apply to this document as well.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
document are to be interpreted as described in [RFC2119]. this document are to be interpreted as described in [RFC2119].
Definitions of XML elements in this document use XML element type Definitions of XML elements in this document use XML element type
declarations (as found in XML Document Type Declarations), described declarations (as found in XML Document Type Declarations),
in Section 3.2 of [REC-XML]. When an XML element type in the "DAV:" described in Section 3.2 of [REC-XML]. When an XML element type in
namespace is referenced in this document outside of the context of an the "DAV:" namespace is referenced in this document outside of the
XML fragment, the string "DAV:" will be prefixed to the element type. context of an XML fragment, the string "DAV:" will be prefixed to
the element type.
2 PRINCIPALS 2 PRINCIPALS
A principal is a network resource that represents a distinct human or A principal is a network resource that represents a distinct human
computational actor that initiates access to network resources. Users or computational actor that initiates access to network resources.
and groups are represented as principals in many implementations; Users and groups are represented as principals in many
other types of principals are also possible. A URI of any scheme MAY implementations; other types of principals are also possible. A URI
be used to identify a principal resource. However, servers of any scheme MAY be used to identify a principal resource.
implementing this specification MUST expose principal resources at an However, servers implementing this specification MUST expose
http(s) URL, which is a privileged scheme that points to resources principal resources at an http(s) URL, which is a privileged scheme
that have additional properties, as described in Section 4. So, a that points to resources that have additional properties, as
principal resource can have multiple URIs, one of which has to be an described in Section 4. So, a principal resource can have multiple
http(s) scheme URL. Although an implementation SHOULD support URIs, one of which has to be an http(s) scheme URL. Although an
implementation SHOULD support PROPFIND and MAY support PROPPATCH to
Clemm, Hopkins, Sedlar, Whitehead [Page 8] access and modify information about a principal, it is not required
PROPFIND and MAY support PROPPATCH to access and modify information to do so.
about a principal, it is not required to do so.
A principal resource may or may not be a collection. If a person or A principal resource may be a group. A group is represented as a
computational agent matches a principal resource that is contained by WebDAV collection, where the members of the group are members of
a collection principal, they also match the collection principal. the WebDAV collection. If a person or computational agent matches
This definition is recursive, and hence if a person or computational a principal resource that is a member of a group, they also match
agent matches a collection principal that is the child of another the group. Membership in a group is recursive, so if a principal is
collection principal, they also match the parent collection a member of group GRPA, and GRPA is a member of group GRPB, then
principal. Membership in a collection principal is also recursive, so the principal is also a member of GRPB.
a principal in a collection principal GRPA contained by collection
principal GRPB is a member of both GRPA and GRPB. Implementations not
supporting recursive membership in principal collections can return
an error if the client attempts to bind collection principals into
other collection principals.
Servers that support aggregation of principals (e.g. groups of users Implementer's Note: It is possible for the collection that
or other groups) MUST manifest them as collection principals. At represents a group to have non-principals as collection members.
minimum, principals and collection principals MUST support the When enumerating the membership of a group, it is necessary to
OPTIONS and PROPFIND methods.
Implementer's Note: Collection principals are first and foremost Clemm, Hopkins, Sedlar, Whitehead [Page 8]
WebDAV collections. Therefore they contain resources as members. retrieve the DAV:resourcetype property of a collection member,
Since there is no requirement that all members of a collection and check it for the DAV:principal XML element (described in
principal need be principals, it is possible for a collection Section 4). If the DAV:principal XML element is not present, the
principal to have non-principals as members. When enumerating the resource is not a principal and may be ignored for the purposes
principals-only membership of a collection principal, it is of determining group membership.
necessary to retrieve the DAV:resourcetype property and check it
for the DAV:principal XML element (described in Section 4). If the
DAV:principal XML element is not present, the resource is not a
principal and may be ignored for the purposes of determining the
principals-only membership of the collection principal.
For example, the collection principal /FOO/ has two members, Bar For example, the collection /FOO/, representing a group, has two
and Baz. Bar is a principal but Baz is not. Therefore when members, Bar and Baz. Bar is a principal but Baz is not.
determining which principals belong to the collection principal Therefore when determining which principals belong to the group,
/FOO/, a client would enumerate the membership using PROPFIND a client would enumerate the membership using PROPFIND while
while asking for the DAV:resourcetype property, and see that only asking for the DAV:resourcetype property, and see that only Bar
Bar has the DAV:principal XML element. Therefore, only Bar is the has the DAV:principal XML element. Therefore, Bar is the only
only principal that is a member of the collection principal /FOO/. principal that is a member of the group represented by /FOO/.
3 PRIVILEGES 3 PRIVILEGES
Ability to perform a given method on a resource SHOULD be controlled Ability to perform a given method on a resource SHOULD be
by one or more privileges. Authors of protocol extensions that controlled by one or more privileges. Authors of protocol
define new HTTP methods SHOULD specify which privileges (by defining extensions that define new HTTP methods SHOULD specify which
new privileges, or mapping to ones below) are required to perform the privileges (by defining new privileges, or mapping to ones below)
method. A principal with no privileges to a resource SHOULD be are required to perform the method. A principal with no privileges
denied any HTTP access to that resource, unless the principal matches to a resource SHOULD be denied any HTTP access to that resource,
unless the principal matches an ACE constructed using the DAV:all,
DAV:authenticated, or DAV:unauthenticated pseudo-principals (see
Section 5.4.1).
Clemm, Hopkins, Sedlar, Whitehead [Page 9] Privileges may be containers of other privileges, in which case
an ACE constructed using the DAV:all, DAV:authenticated, or they are termed aggregate privileges. If a principal is granted or
DAV:unauthenticated pseudo-principals (see Section 5.4.1). denied an aggregate privilege, it is semantically equivalent to
granting or denying each of the aggregated privileges individually.
For example, an implementation may define add-member and remove-
member privileges that control the ability to add and remove an
internal member of a group. Since these privileges control the
ability to update the state of a group, these privileges would be
aggregated by the DAV:write privilege on a group, and granting the
DAV:write privilege on a group would also grant the add-member and
remove-member privileges.
Privileges may be containers of other privileges, in which case they Privileges may have the quality of being abstract, in which case
are termed aggregate privileges. If a principal is granted or denied they cannot be set in an ACE. Aggregate and non-aggregate
an aggregate privilege, it is semantically equivalent to granting or privileges are both capable of being abstract. Abstract privileges
denying each of the aggregated privileges individually. For example, are useful for modeling privileges that otherwise would not be
an implementation may define add-member and remove-member privileges exposed via the protocol. Abstract privileges also provide server
that control the ability to add and remove an internal member of a implementations with flexibility in implementing the privileges
collection. Since these privileges control the ability to update the defined in this specification. For example, if a server is
state of a collection, these privileges would be aggregated by the incapable of separating the read resource capability from the read
DAV:write privilege on a collection, and granting the DAV:write ACL capability, it can still model the DAV:read and DAV:read-acl
privilege on a collection would also grant the add-member and remove- privileges defined in this specification by declaring them
member privileges.
Privileges may have the quality of being abstract, in which case they Clemm, Hopkins, Sedlar, Whitehead [Page 9]
cannot be set in an ACE. Aggregate and non-aggregate privileges are abstract, and containing them within a non-abstract aggregate
both capable of being abstract. Abstract privileges are useful for privilege (say, read-all) that holds DAV:read, and DAV:read-acl. In
modeling privileges that otherwise would not be exposed via the this way, it is possible to set the aggregate privilege, read-all,
protocol. Abstract privileges also provide server implementations thus coupling the setting of DAV:read and DAV:read-acl, but it is
with flexibility in implementing the privileges defined in this not possible to set DAV:read, or DAV:read-acl individually. Since
specification. For example, if a server is incapable of separating aggregate privileges can be abstract, it is also possible to use
the read resource capability from the read ACL capability, it can abstract privileges to group or organize non-abstract privileges.
still model the DAV:read and DAV:read-acl privileges defined in this Privilege containment loops are not allowed, hence a privilege MUST
specification by declaring them abstract, and containing them within NOT contain itself. For example, DAV:read cannot contain DAV:read.
a non-abstract aggregate privilege (say, read-all) that holds
DAV:read, and DAV:read-acl. In this way, it is possible to set the
aggregate privilege, read-all, thus coupling the setting of DAV:read
and DAV:read-acl, but it is not possible to set DAV:read, or
DAV:read-acl individually. Since aggregate privileges can be
abstract, it is also possible to use abstract privileges to group or
organize non-abstract privileges. Privilege containment loops are not
allowed, hence a privilege MUST NOT contain itself. For example,
DAV:read cannot contain DAV:read.
The set of privileges that apply to a particular resource may vary The set of privileges that apply to a particular resource may vary
with the DAV:resourcetype of the resource, as well as between with the DAV:resourcetype of the resource, as well as between
different server implementations. To promote interoperability, different server implementations. To promote interoperability,
however, this specification defines a set of well-known privileges however, this specification defines a set of well-known privileges
(e.g. DAV:read, DAV:write, DAV:read-acl, DAV:write-acl, DAV:read- (e.g. DAV:read, DAV:write, DAV:read-acl, DAV:write-acl, DAV:read-
current-user-privilege-set, and DAV:all), which can at least be used current-user-privilege-set, and DAV:all), which can at least be
to classify the other privileges defined on a particular resource. used to classify the other privileges defined on a particular
The access permissions on null resources (defined in [RFC2518], resource. The access permissions on null resources (defined in
Section 3) are solely those they inherit (if any), and they are not [RFC2518], Section 3) are solely those they inherit (if any), and
discoverable (i.e., the access control properties specified in they are not discoverable (i.e., the access control properties
Section 5 are not defined on null resources). On the transition from specified in Section 5 are not defined on null resources). On the
null to stateful resource, the initial access control list is set by transition from null to stateful resource, the initial access
the server's default ACL value policy (if any). control list is set by the server's default ACL value policy (if
any).
Server implementations MAY define new privileges beyond those defined
in this specification. Privileges defined by individual
Clemm, Hopkins, Sedlar, Whitehead [Page 10] Server implementations MAY define new privileges beyond those
defined in this specification. Privileges defined by individual
implementations MUST NOT use the DAV: namespace, and instead should implementations MUST NOT use the DAV: namespace, and instead should
use a namespace that they control, such as an http scheme URL. use a namespace that they control, such as an http scheme URL.
3.1 DAV:read Privilege 3.1 DAV:read Privilege
The read privilege controls methods that return information about the The read privilege controls methods that return information about
state of the resource, including the resource's properties. Affected the state of the resource, including the resource's properties.
methods include GET and PROPFIND. Additionally, the read privilege Affected methods include GET and PROPFIND. Any implementation-
MAY control the OPTIONS method. defined privilege that also controls access to GET and PROPFIND
must be aggregated under dav:read¨if an ACL grants access to
dav:read, the client may expect that no other privilege needs to be
granted to have access to GET and PROPFIND. Additionally, the read
privilege MAY control the OPTIONS method.
<!ELEMENT read EMPTY> <!ELEMENT read EMPTY>
3.2 DAV:write Privilege 3.2 DAV:write Privilege
The write privilege controls methods that modify the content, dead The write privilege controls methods that lock a resource or modify
properties, or (in the case of a collection) membership of the the content, dead properties, or (in the case of a collection)
resource, such as PUT and PROPPATCH. Note that state modification is membership of the resource, such as PUT and PROPPATCH. Note that
also controlled via locking (see section 5.3 of [WEBDAV]), so
effective write access requires that both write privileges and write Clemm, Hopkins, Sedlar, Whitehead [Page 10]
locking requirements are satisfied. state modification is also controlled via locking (see section 5.3
of [WEBDAV]), so effective write access requires that both write
privileges and write locking requirements are satisfied. Any
implementation-defined privilege that also controls access to
methods modifying content, dead properties or collection membership
must be aggregated under dav:write, e.g. if an ACL grants access to
dav:write, the client may expect that no other privilege needs to
be granted to have access to PUT and PROPPATCH.
<!ELEMENT write EMPTY> <!ELEMENT write EMPTY>
3.3 DAV:read-acl Privilege 3.3 DAV:write-properties
The DAV:write-properties privilege controls methods that modify the
dead properties of the resource, such as PROPPATCH. Whether this
privilege may be used to control access to any live properties is
determined by the implementation. Any implementation-defined
privilege that also controls access to methods modifying dead
properties must be aggregated under dav:write-properties¨e.g. if an
ACL grants access to dav:write-properties, the client can safely
expect that no other privilege needs to be granted to have access
to PROPPATCH.
<!ELEMENT write-properties EMPTY>
3.4 DAV:write-content
The DAV:write-content privilege controls methods that modify the
content or (in the case of a collection) membership of the
resource, such as PUT and DELETE. Any implementation-defined
privilege that also controls access to content or alteration of
collection membership must be aggregated under dav:write-content¨
e.g. if an ACL grants access to dav:write-content, the client can
safely expect that no other privilege needs to be granted to have
access to PUT or DELETE.
<!ELEMENT write-content EMPTY>
3.5 DAV:unlock
The dav:unlock privilege controls the use of the UNLOCK method to
unlock a resource. (Note that while the set of users who may lock
a resource is most commonly the same set of users who may modify a
resource, servers may allow various kinds of administrators to
unlock resources locked by others.) Any privilege controlling
access to UNLOCK must be aggregated under dav:unlock.
<!ELEMENT unlock EMPTY>
Clemm, Hopkins, Sedlar, Whitehead [Page 11]
3.6 DAV:read-acl Privilege
The DAV:read-acl privilege controls the use of PROPFIND to retrieve The DAV:read-acl privilege controls the use of PROPFIND to retrieve
the DAV:acl property of the resource. the DAV:acl property of the resource.
<!ELEMENT read-acl EMPTY> <!ELEMENT read-acl EMPTY>
3.4 DAV:read-current-user-privilege-set Privilege 3.7 DAV:read-current-user-privilege-set Privilege
The DAV:read-current-user-privilege-set privilege controls the use of The DAV:read-current-user-privilege-set privilege controls the use
PROPFIND to retrieve the DAV:current-user-privilege-set property of of PROPFIND to retrieve the DAV:current-user-privilege-set property
the resource. of the resource.
Clients are intended to use this property to visually indicate in Clients are intended to use this property to visually indicate in
their UI items that are dependent on the permissions of a resource, their UI items that are dependent on the permissions of a resource,
for example, by graying out resources that are not writeable. for example, by graying out resources that are not writeable.
This privilege is separate from DAV:read-acl because there is a need This privilege is separate from DAV:read-acl because there is a
to allow most users access to the privileges permitted the current need to allow most users access to the privileges permitted the
user (due to its use in creating the UI), while the full ACL contains current user (due to its use in creating the UI), while the full
information that may not be appropriate for the current authenticated ACL contains information that may not be appropriate for the
user. As a result, the set of users who can view the full ACL is current authenticated user. As a result, the set of users who can
expected to be much smaller than those who can read the current user view the full ACL is expected to be much smaller than those who can
privilege set, and hence distinct privileges are needed for each. read the current user privilege set, and hence distinct privileges
are needed for each.
<!ELEMENT read-current-user-privilege-set EMPTY> <!ELEMENT read-current-user-privilege-set EMPTY>
Clemm, Hopkins, Sedlar, Whitehead [Page 11] 3.8 DAV:write-acl Privilege
3.5 DAV:write-acl Privilege
The DAV:write-acl privilege controls use of the ACL method to modify The DAV:write-acl privilege controls use of the ACL method to
the DAV:acl property of the resource. modify the DAV:acl property of the resource.
<!ELEMENT write-acl EMPTY> <!ELEMENT write-acl EMPTY>
3.6 DAV:all Privilege 3.9 DAV:all Privilege
DAV:all is an aggregate privilege that contains the entire set of DAV:all is an aggregate privilege that contains the entire set of
privileges that can be applied to the resource. privileges that can be applied to the resource.
<!ELEMENT all EMPTY> <!ELEMENT all EMPTY>
3.7 Aggregation of Predefined Privileges 3.10Aggregation of Predefined Privileges
Server implementations are free to aggregate the predefined Server implementations are free to aggregate the predefined
privileges (defined above in Sections 3.1-3.6) subject to the privileges (defined above in Sections 3.1-3.9) subject to the
following limitations: following limitations:
DAV:read-acl MUST NOT contain DAV:read, DAV:write, DAV:write-acl, or Clemm, Hopkins, Sedlar, Whitehead [Page 12]
DAV:read-current-user-privilege-set. DAV:read-acl MUST NOT contain DAV:read, DAV:write, DAV:write-acl,
DAV:write-properties, DAV:write-content, or DAV:read-current-user-
privilege-set.
DAV:write-acl MUST NOT contain DAV:write, DAV:read, DAV:read-acl, or DAV:write-acl MUST NOT contain DAV:write, DAV:read, DAV:read-acl,
DAV:read-current-user-privilege-set. or DAV:read-current-user-privilege-set.
DAV:read-current-user-privilege-set MUST NOT contain DAV:write, DAV:read-current-user-privilege-set MUST NOT contain DAV:write,
DAV:read, DAV:read-acl, or DAV:write-acl. DAV:read, DAV:read-acl, or DAV:write-acl.
DAV:write MUST NOT contain DAV:read, DAV:read-acl, or DAV:read- DAV:write MUST NOT contain DAV:read, DAV:read-acl, or DAV:read-
current-user-privilege-set. current-user-privilege-set.
DAV:read MUST NOT contain DAV:write, or DAV:write-acl. DAV:read MUST NOT contain DAV:write, DAV:write-acl, DAV:write-
properties, or DAV:write-content.
DAV:write MUST contain DAV:write-properties and DAV:write-content.
4 PRINCIPAL PROPERTIES 4 PRINCIPAL PROPERTIES
Principals are manifested to clients as a WebDAV resource, identified Principals are manifested to clients as a WebDAV resource,
by a URL. A principal MUST have a DAV:displayname property (defined identified by a URL. A principal MUST have a DAV:displayname
in Section 13.2 of [RFC2518]), and a DAV:resourcetype property property (defined in Section 13.2 of [RFC2518]), and a
(defined in Section 13.9 of [RFC2518]). Additionally, a principal DAV:resourcetype property (defined in Section 13.9 of [RFC2518]).
MUST report the DAV:principal empty XML element in the value of the Additionally, a principal MUST report the DAV:principal empty XML
DAV:resourcetype property in addition to all other reported elements. element in the value of the DAV:resourcetype property in addition
For example, a collection principal would report DAV:collection and to all other reported elements. For example, a group would report
DAV:principal elements. The element type declaration for DAV:collection and DAV:principal elements. The element type
DAV:principal is: declaration for DAV:principal is:
<!ELEMENT principal EMPTY> <!ELEMENT principal EMPTY>
This protocol defines the following additional property for a This protocol defines the following additional property for a
principal. Since it is expensive, for many servers, to retrieve principal. Since it is expensive, for many servers, to retrieve
access control information, the name and value of this property access control information, the name and value of this property
Clemm, Hopkins, Sedlar, Whitehead [Page 12]
SHOULD NOT be returned by a PROPFIND allprop request (as defined in SHOULD NOT be returned by a PROPFIND allprop request (as defined in
Section 12.14.1 of [RFC2518]). Section 12.14.1 of [RFC2518]).
4.1 DAV:alternate-URI-set 4.1 DAV:alternate-URI-set
This protected property, if non-empty, contains the URIs of network This protected property, if non-empty, contains the URIs of network
resources with additional descriptive information about the resources with additional descriptive information about the
principal. This property identifies additional network resources principal. This property identifies additional network resources
(i.e., it contains one or more URIs) that may be consulted by a (i.e., it contains one or more URIs) that may be consulted by a
client to gain additional knowledge concerning a principal. One client to gain additional knowledge concerning a principal. One
expected use for this property is the storage of an ldap [RFC2255] expected use for this property is the storage of an ldap [RFC2255]
scheme URL. A user-agent encountering an ldap URL could use LDAP scheme URL. A user-agent encountering an ldap URL could use LDAP
[RFC2589] to retrieve additional machine-readable directory [RFC2589] to retrieve additional machine-readable directory
information about the principal, and display that information in its information about the principal, and display that information in
user interface. Support for this property is REQUIRED, and the value
is empty if no alternate URI exists for the principal. Clemm, Hopkins, Sedlar, Whitehead [Page 13]
its user interface. Support for this property is REQUIRED, and the
value is empty if no alternate URI exists for the principal.
<!ELEMENT alternate-URI-set (href*)> <!ELEMENT alternate-URI-set (href*)>
4.2 DAV:principal-URL 4.2 DAV:principal-URL
This protected property contains the URL that MUST be used to A principal may have many URLs, but there must be one primary URL
identify this principal in an ACL request. that clients can use to uniquely identify a principal¨the
principal-URL. This protected property contains the URL that MUST
be used to identify this principal in an ACL request.
<!ELEMENT principal-URL (href)> <!ELEMENT principal-URL (href)>
4.3 DAV:group-membership
This protected property identifies the groups in which the
principal is directly a member. Note that a server may allow a
group to be a member of another group, in which case the DAV:group-
membership of those other groups would need to be queried in order
to determine the groups in which the principal is indirectly a
member.
<!ELEMENT group-membership (href*)>
5 ACCESS CONTROL PROPERTIES 5 ACCESS CONTROL PROPERTIES
This specification defines a number of new properties for WebDAV This specification defines a number of new properties for WebDAV
resources. Access control properties may be retrieved just like resources. Access control properties may be retrieved just like
other WebDAV properties, using the PROPFIND method. Since it is other WebDAV properties, using the PROPFIND method. Since it is
expensive, for many servers, to retrieve access control information, expensive, for many servers, to retrieve access control
a PROPFIND allprop request (as defined in Section 12.14.1 of information, a PROPFIND allprop request (as defined in Section
[RFC2518]) SHOULD NOT return the names and values of the properties 12.14.1 of [RFC2518]) SHOULD NOT return the names and values of the
defined in this section. properties defined in this section.
HTTP resources that support the WebDAV Access Control Protocol MUST HTTP resources that support the WebDAV Access Control Protocol MUST
contain the following properties. Null resources (described in contain the following properties. Null resources (described in
Section 3 of [RFC2518]) MUST NOT contain the following properties: Section 3 of [RFC2518]) MUST NOT contain the following properties:
5.1 DAV:owner 5.1 DAV:owner
This protected property identifies a particular principal as being This protected property identifies a particular principal as being
the "owner" of the resource. Since the owner of a resource often has the "owner" of the resource. Since the owner of a resource often
special access control capabilities (e.g., the owner frequently has has special access control capabilities (e.g., the owner frequently
permanent DAV:write-acl privilege), clients might display the has permanent DAV:write-acl privilege), clients might display the
resource owner in their user interface. resource owner in their user interface.
Clemm, Hopkins, Sedlar, Whitehead [Page 14]
<!ELEMENT owner (href)> <!ELEMENT owner (href)>
Clemm, Hopkins, Sedlar, Whitehead [Page 13]
5.1.1 Example: Retrieving DAV:owner 5.1.1 Example: Retrieving DAV:owner
This example shows a client request for the value of the DAV:owner This example shows a client request for the value of the DAV:owner
property from a collection resource with URL property from a collection resource with URL
http://www.webdav.org/papers/. The principal making the request is http://www.webdav.org/papers/. The principal making the request is
authenticated using Digest authentication. The value of DAV:owner is authenticated using Digest authentication. The value of DAV:owner
the URL http://www.webdav.org/_acl/users/gstein, wrapped in the is the URL http://www.webdav.org/_acl/users/gstein, wrapped in the
DAV:href XML element. DAV:href XML element.
>> Request << >> Request <<
PROPFIND /papers/ HTTP/1.1 PROPFIND /papers/ HTTP/1.1
Host: www.webdav.org Host: www.webdav.org
Content-type: text/xml; charset="utf-8" Content-type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
Depth: 0 Depth: 0
Authorization: Digest username="jim", Authorization: Digest username="jim",
skipping to change at line 683 skipping to change at line 734
<D:response> <D:response>
<D:href>http://www.webdav.org/papers/</D:href> <D:href>http://www.webdav.org/papers/</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<D:owner> <D:owner>
<D:href>http://www.webdav.org/_acl/users/gstein</D:href> <D:href>http://www.webdav.org/_acl/users/gstein</D:href>
</D:owner> </D:owner>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:propstat>
Clemm, Hopkins, Sedlar, Whitehead [Page 15]
</D:response> </D:response>
</D:multistatus> </D:multistatus>
Clemm, Hopkins, Sedlar, Whitehead [Page 14]
5.1.2 Example: An Attempt to Set DAV:owner 5.1.2 Example: An Attempt to Set DAV:owner
The following example shows a client request to modify the value of The following example shows a client request to modify the value of
the DAV:owner property on the resource with URL the DAV:owner property on the resource with URL
http://www.webdav.org/papers/. Since DAV:owner is a protected <http://www.webdav.org/papers>. Since DAV:owner is a protected
property, the server responds with a 207 (Multi-Status) response that property, the server responds with a 207 (Multi-Status) response
contains a 403 (Forbidden) status code for the act of setting that contains a 403 (Forbidden) status code for the act of setting
DAV:owner. Section 8.2.1 of [RFC2518] describes PROPPATCH status code DAV:owner. Section 8.2.1 of [RFC2518] describes PROPPATCH status
information, and Section 11 of [RFC2518] describes the Multi-Status code information, and Section 11 of [RFC2518] describes the Multi-
response. Status response.
>> Request << >> Request <<
PROPPATCH /papers/ HTTP/1.1 PROPPATCH /papers/ HTTP/1.1
Host: www.webdav.org Host: www.webdav.org
Content-type: text/xml; charset="utf-8" Content-type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
Depth: 0 Depth: 0
Authorization: Digest username="jim", Authorization: Digest username="jim",
realm="jim@webdav.org", nonce="...", realm="jim@webdav.org", nonce="...",
skipping to change at line 731 skipping to change at line 783
>> Response << >> Response <<
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"> <D:multistatus xmlns:D="DAV:">
<D:response> <D:response>
<D:href>http://www.webdav.org/papers/</D:href> <D:href>http://www.webdav.org/papers/</D:href>
Clemm, Hopkins, Sedlar, Whitehead [Page 16]
<D:propstat> <D:propstat>
<D:prop><D:owner/></D:prop> <D:prop><D:owner/></D:prop>
<D:status>HTTP/1.1 403 Forbidden</D:status> <D:status>HTTP/1.1 403 Forbidden</D:status>
<D:responsedescription>Failure to set protected property <D:responsedescription>
(DAV:owner) Failure to set protected property (DAV:owner)
</D:responsedescription> </D:responsedescription>
</D:propstat> </D:propstat>
Clemm, Hopkins, Sedlar, Whitehead [Page 15]
</D:response> </D:response>
</D:multistatus> </D:multistatus>
5.2 DAV:supported-privilege-set 5.2 DAV:supported-privilege-set
This is a protected property that identifies the privileges defined This is a protected property that identifies the privileges
for the resource. defined for the resource.
<!ELEMENT supported-privilege-set (supported-privilege*)> <!ELEMENT supported-privilege-set (supported-privilege*)>
Each privilege appears as an XML element, where aggregate Each privilege appears as an XML element, where aggregate
privileges list as sub-elements all of the privileges that they privileges list as sub-elements all of the privileges that they
aggregate. aggregate.
<!ELEMENT supported-privilege (privilege, abstract?, description, <!ELEMENT supported-privilege
supported-privilege*)> (privilege, abstract?, description, supported-privilege*)>
<!ELEMENT privilege ANY> <!ELEMENT privilege ANY>
An abstract privilege MUST NOT be used in an ACE for that resource. An abstract privilege MUST NOT be used in an ACE for that resource.
Servers MUST fail an attempt to set an abstract privilege. Servers MUST fail an attempt to set an abstract privilege.
<!ELEMENT abstract EMPTY> <!ELEMENT abstract EMPTY>
A description is a human-readable description of what this privilege A description is a human-readable description of what this
controls access to. Servers MUST indicate the human language of the privilege controls access to. Servers MUST indicate the human
description using the xml:lang attribute and SHOULD consider the HTTP language of the description using the xml:lang attribute and SHOULD
Accept-Language request header when selecting one of multiple consider the HTTP Accept-Language request header when selecting one
available languages. of multiple available languages.
<!ELEMENT description #PCDATA> <!ELEMENT description #PCDATA>
It is envisioned that a WebDAV ACL-aware administrative client would It is envisioned that a WebDAV ACL-aware administrative client
list the supported privileges in a dialog box, and allow the user to would list the supported privileges in a dialog box, and allow the
choose non-abstract privileges to apply in an ACE. The privileges user to choose non-abstract privileges to apply in an ACE. The
tree is useful programmatically to map well-known privileges (defined privileges tree is useful programmatically to map well-known
by WebDAV or other standards groups) into privileges that are privileges (defined by WebDAV or other standards groups) into
supported by any particular server implementation. The privilege privileges that are supported by any particular server
tree also serves to hide complexity in implementations allowing large implementation. The privilege tree also serves to hide complexity
number of privileges to be defined by displaying aggregates to the in implementations allowing large number of privileges to be
user. defined by displaying aggregates to the user.
5.2.1 Example: Retrieving a List of Privileges Supported on a Resource Clemm, Hopkins, Sedlar, Whitehead [Page 17]
5.2.1 Example: Retrieving a List of Privileges Supported on a
Resource
This example shows a client request for the DAV:supported-privilege- This example shows a client request for the DAV:supported-
set property on the resource http://www.webdav.org/papers/. The value privilege-set property on the resource
of the DAV:supported-privilege-set property is a tree of supported http://www.webdav.org/papers/. The value of the DAV:supported-
privileges: privilege-set property is a tree of supported privileges (using
"[XML Namespace , localname]" to identify each privilege):
DAV:all (aggregate, abstract) [DAV:, all] (aggregate, abstract)
| |
+-- DAV:read (aggregate) +-- [DAV:, read] (aggregate)
Clemm, Hopkins, Sedlar, Whitehead [Page 16]
| |
+-- DAV:read-acl (abstract) +-- [DAV:, read-acl] (abstract)
+-- DAV:read-current-user-privilege-set (abstract) +-- [DAV:, read-current-user-privilege-set]
+-- DAV:write (aggregate) (abstract)
| |
+-- DAV:write-acl (abstract) +-- [DAV:, write] (aggregate)
|
+-- [DAV:, write-acl] (abstract)
+-- [DAV:, write-properties]
+-- [DAV:, write-content]
|
+-- [DAV:, unlock]
This privilege tree is not normative, and many possible privilege This privilege tree is not normative (except that it reflects the
trees are possible. normative aggregation rules given in Section 3.10), and many
possible privilege trees are possible.
>> Request << >> Request <<
PROPFIND /papers/ HTTP/1.1 PROPFIND /papers/ HTTP/1.1
Host: www.webdav.org Host: www.webdav.org
Content-type: text/xml; charset="utf-8" Content-type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
Depth: 0 Depth: 0
Authorization: Digest username="gclemm", Authorization: Digest username="gclemm",
realm="gclemm@webdav.org", nonce="...", realm="gclemm@webdav.org", nonce="...",
uri="/papers/", response="...", opaque="..." uri="/papers/", response="...", opaque="..."
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D="DAV:"> <D:propfind xmlns:D="DAV:">
<D:prop> <D:prop>
<D:supported-privilege-set/> <D:supported-privilege-set/>
</D:prop> </D:prop>
</D:propfind> </D:propfind>
Clemm, Hopkins, Sedlar, Whitehead [Page 18]
>> Response << >> Response <<
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"> <D:multistatus xmlns:D="DAV:">
<D:response> <D:response>
<D:href>http://www.webdav.org/papers/</D:href> <D:href>http://www.webdav.org/papers/</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<D:supported-privilege-set> <D:supported-privilege-set>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:all/> </D:privilege> <D:privilege> <D:all/> </D:privilege>
<D:abstract/> <D:abstract/>
<D:description xml:lang="en">Any <D:description xml:lang="en">Any
operation</D:description> operation</D:description>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:read/> </D:privilege> <D:privilege> <D:read/> </D:privilege>
Clemm, Hopkins, Sedlar, Whitehead [Page 17]
<D:description xml:lang="en">Read any <D:description xml:lang="en">Read any
object</D:description> object</D:description>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:read-acl/> </D:privilege> <D:privilege> <D:read-acl/> </D:privilege>
<D:abstract/> <D:abstract/>
<D:description xml:lang="en">Read <D:description xml:lang="en">Read
ACL</D:description> ACL</D:description>
</D:supported-privilege> </D:supported-privilege>
</D:supported-privilege>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:privilege>
<D:read-current-user-privilege-set/> <D:read-current-user-privilege-set/>
</D:privilege> </D:privilege>
<D:abstract/> <D:abstract/>
<D:description xml:lang="en">Read current user <D:description xml:lang="en">Read current user
privilege set property</D:description> privilege set property</D:description>
</D:supported-privilege> </D:supported-privilege>
</D:supported-privilege>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:write/> </D:privilege> <D:privilege> <D:write/> </D:privilege>
<D:description xml:lang="en">Write any <D:description xml:lang="en">Write any
object</D:description> object</D:description>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:write-acl/> </D:privilege> <D:privilege> <D:write-acl/> </D:privilege>
<D:description xml:lang="en">Write <D:description xml:lang="en">Write
ACL</D:description> ACL</D:description>
<D:abstract/> <D:abstract/>
Clemm, Hopkins, Sedlar, Whitehead [Page 19]
</D:supported-privilege> </D:supported-privilege>
<D:supported-privilege>
<D:privilege> <D:write-properties/>
</D:privilege>
<D:description xml:lang="en">Write
properties</D:description>
</D:supported-privilege>
<D:supported-privilege>
<D:privilege> <D:write-content/> </D:privilege>
<D:description xml:lang="en">Write resource
content</D:description>
</D:supported-privilege>
</D:supported-privilege>
<D:supported-privilege>
<D:privilege> <D:unlock/> </D:privilege>
<D:description xml:lang="en">Unlock
resource</D:description>
</D:supported-privilege> </D:supported-privilege>
</D:supported-privilege> </D:supported-privilege>
</D:supported-privilege-set> </D:supported-privilege-set>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
5.3 DAV:current-user-privilege-set 5.3 DAV:current-user-privilege-set
DAV:current-user-privilege-set is a protected property containing the DAV:current-user-privilege-set is a protected property containing
exact set of privileges (as computed by the server) granted to the the exact set of privileges (as computed by the server) granted to
currently authenticated HTTP user. Aggregate privileges and their the currently authenticated HTTP user. Aggregate privileges and
contained privileges are listed. A user-agent can use the value of their contained privileges are listed. A user-agent can use the
this property to adjust its user interface to make actions value of this property to adjust its user interface to make actions
inaccessible (e.g., by graying out a menu item or button) for which inaccessible (e.g., by graying out a menu item or button) for which
the current principal does not have permission. This is particularly the current principal does not have permission. This is
useful for an access control user interface, which can be constructed particularly useful for an access control user interface, which can
without knowing the ACE combining semantics of the server. This be constructed without knowing the ACE combining semantics of the
property is also useful for determining what operations the current server. This property is also useful for determining what
principal can perform, without having to actually execute an operations the current principal can perform, without having to
operation. actually execute an operation.
Clemm, Hopkins, Sedlar, Whitehead [Page 18]
<!ELEMENT current-user-privilege-set (privilege*)> <!ELEMENT current-user-privilege-set (privilege*)>
<!ELEMENT privilege ANY> <!ELEMENT privilege ANY>
If the current user is granted a specific privilege, that privilege If the current user is granted a specific privilege, that privilege
must belong to the set of privileges that may be set on this must belong to the set of privileges that may be set on this
resource. Therefore, each element in the DAV:current-user-privilege- resource. Therefore, each element in the DAV:current-user-
set property MUST identify a non-abstract privilege from the
DAV:supported-privilege-set property.
5.3.1 Example: Retrieving the UserĂs Current Set of Assigned Privileges Clemm, Hopkins, Sedlar, Whitehead [Page 20]
privilege-set property MUST identify a non-abstract privilege from
the DAV:supported-privilege-set property.
5.3.1 Example: Retrieving the User's Current Set of Assigned
Privileges
Continuing the example from Section 5.2.1, this example shows a Continuing the example from Section 5.2.1, this example shows a
client requesting the DAV:current-user-privilege-set property from client requesting the DAV:current-user-privilege-set property from
the resource with URL http://www.webdav.org/papers/. The username of the resource with URL http://www.webdav.org/papers/. The username
the principal making the request is ˘khare", and Digest of the principal making the request is "khare", and Digest
authentication is used in the request. The principal with username authentication is used in the request. The principal with username
˘khare" has been granted the DAV:read privilege. Since the DAV:read "khare" has been granted the DAV:read privilege. Since the DAV:read
privilege contains the DAV:read-acl and DAV:read-current-user- privilege contains the DAV:read-acl and DAV:read-current-user-
privilege-set privileges (see Section 5.2.1), the principal with privilege-set privileges (see Section 5.2.1), the principal with
username ˘khare" can read the ACL property, and the DAV:current-user- username "khare" can read the ACL property, and the DAV:current-
privilege-set property. However, the DAV:all, DAV:read-acl, user-privilege-set property. However, the DAV:all, DAV:read-acl,
DAV:write-acl and DAV:read-current-user-privilege-set privileges are DAV:write-acl and DAV:read-current-user-privilege-set privileges
not listed in the value of DAV:current-user-privilege-set, since (for are not listed in the value of DAV:current-user-privilege-set,
this example) they are abstract privileges. DAV:write is not listed since (for this example) they are abstract privileges. DAV:write is
since the principal with username ˘khare" is not listed in an ACE not listed since the principal with username "khare" is not listed
granting that principal write permission. in an ACE granting that principal write permission.
>> Request << >> Request <<
PROPFIND /papers/ HTTP/1.1 PROPFIND /papers/ HTTP/1.1
Host: www.webdav.org Host: www.webdav.org
Content-type: text/xml; charset="utf-8" Content-type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
Depth: 0 Depth: 0
Authorization: Digest username="khare", Authorization: Digest username="khare",
realm="khare@webdav.org", nonce="...", realm="khare@webdav.org", nonce="...",
skipping to change at line 944 skipping to change at line 1023
<D:current-user-privilege-set/> <D:current-user-privilege-set/>
</D:prop> </D:prop>
</D:propfind> </D:propfind>
>> Response << >> Response <<
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
Clemm, Hopkins, Sedlar, Whitehead [Page 19]
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
Clemm, Hopkins, Sedlar, Whitehead [Page 21]
<D:multistatus xmlns:D="DAV:"> <D:multistatus xmlns:D="DAV:">
<D:response> <D:response>
<D:href>http://www.webdav.org/papers/</D:href> <D:href>http://www.webdav.org/papers/</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<D:current-user-privilege-set> <D:current-user-privilege-set>
<D:privilege> <D:read/> </D:privilege> <D:privilege> <D:read/> </D:privilege>
</D:current-user-privilege-set> </D:current-user-privilege-set>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
5.4 DAV:acl 5.4 DAV:acl
This is a protected property that specifies the list of access This is a protected property that specifies the list of access
control entries (ACEs), which define what principals are to get what control entries (ACEs), which define what principals are to get
privileges for this resource. what privileges for this resource.
<!ELEMENT acl (ace*)> <!ELEMENT acl (ace | inherited-acl)* >
Each DAV:ace element specifies the set of privileges to be either Each DAV:ace element specifies the set of privileges to be either
granted or denied to a single principal. If the DAV:acl property is granted or denied to a single principal. If the DAV:acl property
empty, no principal is granted any privilege. is empty, no principal is granted any privilege.
<!ELEMENT ace (principal, (grant|deny), protected?, inherited?)> <!ELEMENT ace (invert | principal, (grant|deny), protected?,
inherited?)>
5.4.1 ACE Principal 5.4.1 ACE Principal
The DAV:principal element identifies the principal to which this ACE The DAV:principal element identifies the principal to which this
applies. ACE applies.
<!ELEMENT principal ((href) <!ELEMENT principal ((href)
| all | authenticated | unauthenticated | all | authenticated | unauthenticated
| property | self)> | property | self)>
The current user matches DAV:href only if that user is authenticated The current user matches DAV:href only if that user is
as being (or being a member of) the principal identified by the URL authenticated as being (or being a member of) the principal
contained by that DAV:href. identified by the URL contained by that DAV:href.
The current user always matches DAV:all. The current user always matches DAV:all.
<!ELEMENT all EMPTY> <!ELEMENT all EMPTY>
The current user matches DAV:authenticated only if authenticated. The current user matches DAV:authenticated only if authenticated.
Clemm, Hopkins, Sedlar, Whitehead [Page 22]
<!ELEMENT authenticated EMPTY> <!ELEMENT authenticated EMPTY>
Clemm, Hopkins, Sedlar, Whitehead [Page 20]
The current user matches DAV:unauthenticated only if not The current user matches DAV:unauthenticated only if not
authenticated. authenticated.
<!ELEMENT unauthenticated EMPTY> <!ELEMENT unauthenticated EMPTY>
DAV:all is the union of DAV:authenticated, and DAV:unauthenticated. DAV:all is the union of DAV:authenticated, and DAV:unauthenticated.
For a given request, the user matches either DAV:authenticated, or For a given request, the user matches either DAV:authenticated, or
DAV:unauthenticated, but not both (that is, DAV:authenticated and DAV:unauthenticated, but not both (that is, DAV:authenticated and
DAV:unauthenticated are disjoint sets). DAV:unauthenticated are disjoint sets).
The current user matches a DAV:property principal in a DAV:acl The current user matches a DAV:property principal in a DAV:acl
property of a resource only if the value of the identified property property of a resource only if the value of the identified property
of that resource contains at most one DAV:href XML element, the URI of that resource contains at most one DAV:href XML element, the URI
value of DAV:href identifies a principal, and the current user is value of DAV:href identifies a principal, and the current user is
authenticated as being (or being a member of) that principal. For authenticated as being (or being a member of) that principal. For
example, if the DAV:property element contained <DAV:owner/>, the example, if the DAV:property element contained <DAV:owner/>, the
current user would match the DAV:property principal only if the current user would match the DAV:property principal only if the
current user is authenticated as matching the principal identified by current user is authenticated as matching the principal identified
the DAV:owner property of the resource. by the DAV:owner property of the resource.
<!ELEMENT property ANY> <!ELEMENT property ANY>
Alternately, some servers may support ACEs applying to those users
NOT matching the current principal, e.g. all users not in a
particular group. This can be done by wrapping the dav:principal
element with dav:invert.
<!ELEMENT invert principal>
The current user matches DAV:self in a DAV:acl property of the The current user matches DAV:self in a DAV:acl property of the
resource only if that resource is a principal object and the current resource only if that resource is a principal and that principal
user is authenticated as being that principal or a member of that matches the current user or, if the principal is a group, a member
principal collection. of that group matches the current user.
<!ELEMENT self EMPTY> <!ELEMENT self EMPTY>
5.4.2 ACE Grant and Deny 5.4.2 ACE Grant and Deny
Each DAV:grant or DAV:deny element specifies the set of privileges to Each DAV:grant or DAV:deny element specifies the set of privileges
be either granted or denied to the specified principal. A DAV:grant to be either granted or denied to the specified principal. A
or DAV:deny element of the DAV:acl of a resource MUST only contain DAV:grant or DAV:deny element of the DAV:acl of a resource MUST
non-abstract elements specified in the DAV:supported-privilege-set of only contain non-abstract elements specified in the DAV:supported-
that resource. privilege-set of that resource.
<!ELEMENT grant (privilege+)> <!ELEMENT grant (privilege+)>
<!ELEMENT deny (privilege+)> <!ELEMENT deny (privilege+)>
Clemm, Hopkins, Sedlar, Whitehead [Page 23]
<!ELEMENT privilege ANY> <!ELEMENT privilege ANY>
5.4.3 ACE Protection 5.4.3 ACE Protection
A server indicates an ACE is protected by including the DAV:protected A server indicates an ACE is protected by including the
element in the ACE. If the ACL of a resource contains an ACE with a DAV:protected element in the ACE. If the ACL of a resource contains
DAV:protected element, an attempt to remove that ACE from the ACL an ACE with a DAV:protected element, an attempt to remove that ACE
MUST fail.. from the ACL MUST fail.
<!ELEMENT protected EMPTY> <!ELEMENT protected EMPTY>
Clemm, Hopkins, Sedlar, Whitehead [Page 21]
5.4.4 ACE Inheritance 5.4.4 ACE Inheritance
The presence of a DAV:inherited element indicates that this ACE is The presence of a DAV:inherited element indicates that this ACE is
inherited from another resource that is identified by the URL inherited from another resource that is identified by the URL
contained in a DAV:href element. An inherited ACE cannot be modified contained in a DAV:href element. An inherited ACE cannot be
directly, but instead the ACL on the resource from which it is modified directly, but instead the ACL on the resource from which
inherited must be modified. it is inherited must be modified.
Note that ACE inheritance is not the same as ACL initialization. ACL Note that ACE inheritance is not the same as ACL initialization.
initialization defines the ACL that a newly created resource will use ACL initialization defines the ACL that a newly created resource
(if not specified). ACE inheritance refers to an ACE that is will use (if not specified). ACE inheritance refers to an ACE that
logically shared - where an update to the resource containing an ACE is logically shared - where an update to the resource containing an
will affect the ACE of each resource that inherits that ACE. The ACE will affect the ACE of each resource that inherits that ACE.
method by which ACLs are initialized or by which ACEs are inherited The method by which ACLs are initialized or by which ACEs are
is not defined by this document. inherited is not defined by this document.
<!ELEMENT inherited (href)> <!ELEMENT inherited (href)>
5.4.5 Example: Retrieving a ResourceĂs Access Control List 5.4.5 Example: Retrieving a Resource's Access Control List
Continuing the example from Sections 5.2.1 and 5.3.1, this example Continuing the example from Sections 5.2.1 and 5.3.1, this example
shows a client requesting the DAV:acl property from the resource with shows a client requesting the DAV:acl property from the resource
URL http://www.webdav.org/papers/. There are two ACEs defined in this with URL http://www.webdav.org/papers/. There are two ACEs defined
ACL: in this ACL:
ACE #1: The principal collection identified by URL ACE #1: The group identified by URL
http://www.webdav.org/_acl/groups/maintainers/ (the group of site http://www.webdav.org/_acl/groups/maintainers/ (the group of site
maintainers) is granted DAV:write privilege. Since (for this example) maintainers) is granted DAV:write privilege. Since (for this
DAV:write contains the DAV:write-acl privilege (see Section 5.2.1), example) DAV:write contains the DAV:write-acl privilege (see
this means the ˘maintainers" group can also modify the access control Section 5.2.1), this means the "maintainers" group can also modify
list. the access control list.
ACE #2: All principals (DAV:all) are granted the DAV:read privilege. ACE #2: All principals (DAV:all) are granted the DAV:read
Since (for this example) DAV:read contains DAV:read-acl and DAV:read- privilege. Since (for this example) DAV:read contains DAV:read-acl
current-user-privilege-set, this means all users (including all and DAV:read-current-user-privilege-set, this means all users
members of the ˘maintainers" group) can read the DAV:acl property and (including all members of the "maintainers" group) can read the
the DAV:current-user-privilege-set property. DAV:acl property and the DAV:current-user-privilege-set property.
Clemm, Hopkins, Sedlar, Whitehead [Page 24]
>> Request << >> Request <<
PROPFIND /papers/ HTTP/1.1 PROPFIND /papers/ HTTP/1.1
Host: www.webdav.org Host: www.webdav.org
Content-type: text/xml; charset="utf-8" Content-type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
Depth: 0 Depth: 0
Authorization: Digest username="masinter", Authorization: Digest username="masinter",
realm="masinter@webdav.org", nonce="...", realm="masinter@webdav.org", nonce="...",
uri="/papers/", response="...", opaque="..." uri="/papers/", response="...", opaque="..."
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
Clemm, Hopkins, Sedlar, Whitehead [Page 22]
<D:propfind xmlns:D="DAV:"> <D:propfind xmlns:D="DAV:">
<D:prop> <D:prop>
<D:acl/> <D:acl/>
</D:prop> </D:prop>
</D:propfind> </D:propfind>
>> Response << >> Response <<
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
skipping to change at line 1135 skipping to change at line 1221
</D:principal> </D:principal>
<D:grant> <D:grant>
<D:privilege> <D:write/> </D:privilege> <D:privilege> <D:write/> </D:privilege>
</D:grant> </D:grant>
</D:ace> </D:ace>
<D:ace> <D:ace>
<D:principal> <D:principal>
<D:all/> <D:all/>
</D:principal> </D:principal>
<D:grant> <D:grant>
Clemm, Hopkins, Sedlar, Whitehead [Page 25]
<D:privilege> <D:read/> </D:privilege> <D:privilege> <D:read/> </D:privilege>
</D:grant> </D:grant>
</D:ace> </D:ace>
</D:acl> </D:acl>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
5.5 DAV:acl-semantics 5.5 DAV:inherited-acl
This is a protected property that lists a set of other resources
whose ACLs also control the access to this resource. To have a
privilege on a resource, not only must the ACEs defined in the ACL
on that resource grant the privilege, but so must each ACL in a
dav:inherited-acl tag. Effectively, the privileges granted by the
current ACL are ANDĂed with the privileges granted by each
inherited ACL. The order in which the inherited-acl tag appears in
an ACL is relevant, regardless of the ACL semantics (see below).
<!ELEMENT inherited-acl (href)>
5.6 DAV:acl-semantics
This is a protected property that defines the ACL semantics. These This is a protected property that defines the ACL semantics. These
semantics define how multiple ACEs that match the current user are semantics define how multiple ACEs that match the current user are
Clemm, Hopkins, Sedlar, Whitehead [Page 23]
combined, what are the constraints on how ACEs can be ordered, and combined, what are the constraints on how ACEs can be ordered, and
which principals must have an ACE. A client user interface could use which principals must have an ACE. A client user interface could
the value of this property to provide feedback to a human operator use the value of this property to provide feedback to a human
concerning the impact of proposed changes to an ACL. Alternately, a operator concerning the impact of proposed changes to an ACL.
client can use this property to help it determine, before submitting Alternately, a client can use this property to help it determine,
an ACL method invocation, what ACL changes it needs to make to before submitting an ACL method invocation, what ACL changes it
accomplish a specific goal (or whether that goal is even achievable needs to make to accomplish a specific goal (or whether that goal
on this server). is even achievable on this server).
Since it is not practical to require all implementations to use the Since it is not practical to require all implementations to use the
same ACL semantics, the DAV:acl-semantics property is used to same ACL semantics, the DAV:acl-semantics property is used to
identify the ACL semantics for a particular resource. The DAV:acl- identify the ACL semantics for a particular resource. The DAV:acl-
semantics element is defined in Section 6. semantics element is defined in Section 6.
5.5.1 Example: Retrieving DAV:acl-semantics 5.6.1 Example: Retrieving DAV:acl-semantics
In this example, the client requests the value of the DAV:acl- In this example, the client requests the value of the DAV:acl-
semantics property. Digest authentication provides credentials for semantics property. Digest authentication provides credentials for
the principal operating the client. In this example, the ACE the principal operating the client. In this example, the ACE
Clemm, Hopkins, Sedlar, Whitehead [Page 26]
combination semantics are DAV:first-match, described in Section combination semantics are DAV:first-match, described in Section
6.1.1, the ACE ordering semantics are not specified (some value other 6.1.1, the ACE ordering semantics are not specified (some value
than DAV:deny-before-grant, described in Section 6.2.1), the other than DAV:deny-before-grant, described in Section 6.2.1), the
DAV:allowed-ace element states that only one ACE is permitted for DAV:allowed-ace element states that only one ACE is permitted for
each principal, and an ACE describing the privileges granted the each principal, and an ACE describing the privileges granted the
DAV:all principal must exist in every ACL. DAV:all principal must exist in every ACL.
>> Request << >> Request <<
PROPFIND /papers/ HTTP/1.1 PROPFIND /papers/ HTTP/1.1
Host: www.webdav.org Host: www.webdav.org
Content-type: text/xml; charset="utf-8" Content-type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
skipping to change at line 1199 skipping to change at line 1300
<D:propfind xmlns:D="DAV:"> <D:propfind xmlns:D="DAV:">
<D:prop> <D:prop>
<D:acl-semantics/> <D:acl-semantics/>
</D:prop> </D:prop>
</D:propfind> </D:propfind>
>> Response << >> Response <<
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Clemm, Hopkins, Sedlar, Whitehead [Page 24]
Content-Length: xxx Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"> <D:multistatus xmlns:D="DAV:">
<D:response> <D:response>
<D:href>http://www.webdav.org/papers/</D:href> <D:href>http://www.webdav.org/papers/</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<D:acl-semantics> <D:acl-semantics>
<D:ace-combination> <D:ace-combination>
<D:first-match/> <D:first-match/>
</D:ace-combination> </D:ace-combination>
<D:ace-ordering/> <D:ace-ordering/>
<D:allowed-ace> <D:allowed-ace>
<D:principal-only-one-ace/> <D:principal-only-one-ace/>
</D:allowed-ace> </D:allowed-ace>
Clemm, Hopkins, Sedlar, Whitehead [Page 27]
<D:required-principal> <D:required-principal>
<D:all/> <D:all/>
</D:required-principal> </D:required-principal>
</D:acl-semantics> </D:acl-semantics>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:propstat>
<D:response> <D:response>
</D:multistatus> </D:multistatus>
5.6 DAV:principal-collection-set 5.7 DAV:principal-collection-set
This protected property contains zero, one, or more URLs that This protected property of a resource contains a set of URLs that
identify a collection principal. It is expected that implementations identify the root collections that contain the principals that are
of this protocol will typically use a relatively small number of available on the server that implements this resource. An access
locations in the URL namespace for principals, and collection control protocol user agent could use the contents of
principals. In cases where this assumption holds, the DAV:principal- DAV:principal-collection-set to retrieve the DAV:displayname
collection-set property will contain a small set of URLs identifying property (specified in Section 13.2 of [RFC2518]) of all principals
the top of a collection hierarchy containing multiple principals and on that server, thereby yielding human-readable names for each
collection principals. An access control protocol user agent could principal that could be displayed in a user interface.
use the contents of DAV:principal-collection-set to retrieve the
DAV:displayname property (specified in Section 13.2 of [RFC2518]) of
all principals on that server, thereby yielding human-readable names
for each principal that could be displayed in a user interface.
<!ELEMENT principal-collection-set (href*)> <!ELEMENT principal-collection-set (href*)>
Since different servers can control different parts of the URL Since different servers can control different parts of the URL
namespace, different resources on the same host MAY have different namespace, different resources on the same host MAY have different
DAV:principal-collection-set values. The collections specified in the DAV:principal-collection-set values. The collections specified in
DAV:principal-collection-set MAY be located on different hosts from the DAV:principal-collection-set MAY be located on different hosts
the resource. The URLs in DAV:principal-collection-set SHOULD be http from the resource. The URLs in DAV:principal-collection-set SHOULD
or https scheme URLs. For security and scalability reasons, a server be http or https scheme URLs. For security and scalability reasons,
MAY report only a subset of the entire set of known collection a server MAY report only a subset of the entire set of known
principal collections, and therefore clients should not assume they
Clemm, Hopkins, Sedlar, Whitehead [Page 25] have retrieved an exhaustive listing. Additionally, a server MAY
principals, and therefore clients should not assume they have elect to report none of the principal collections it knows about,
retrieved an exhaustive listing. Additionally, a server MAY elect to in which case the property value would be empty.
report none of the collection principals it knows about, in which
case the property value would be empty.
The value of DAV:principal-collection-set gives the scope of the The value of DAV:principal-collection-set gives the scope of the
DAV:principal-property-search REPORT (defined in Section 9.4). DAV:principal-property-search REPORT (defined in Section 9.4).
Clients use the DAV:principal-property-search REPORT to populate Clients use the DAV:principal-property-search REPORT to populate
their user interface with a list of principals. Therefore, servers their user interface with a list of principals. Therefore, servers
that limit a client's ability to obtain principal information will that limit a client's ability to obtain principal information will
interfere with the client's ability to manipulate access control interfere with the client's ability to manipulate access control
lists, due to the difficulty of getting the URL of a principal for lists, due to the difficulty of getting the URL of a principal for
use in an ACE. use in an ACE.
5.6.1 Example: Retrieving DAV:principal-collection-set Clemm, Hopkins, Sedlar, Whitehead [Page 28]
5.7.1 Example: Retrieving DAV:principal-collection-set
In this example, the client requests the value of the DAV:principal- In this example, the client requests the value of the
collection-set property on the collection resource identified by URL DAV:principal-collection-set property on the collection resource
http://www.webdav.org/papers/. The property contains the two URLs, identified by URL http://www.webdav.org/papers/. The property
http://www.webdav.org/_acl/users/ and contains the two URLs, http://www.webdav.org/_acl/users/ and
http://www.webdav.org/_acl/groups/, both wrapped in <DAV:href> XML http://www.webdav.org/_acl/groups/, both wrapped in <DAV:href> XML
elements. Digest authentication provides credentials for the elements. Digest authentication provides credentials for the
principal operating the client. principal operating the client.
The client might reasonably follow this request with two separate The client might reasonably follow this request with two separate
PROPFIND requests to retrieve the DAV:displayname property of the PROPFIND requests to retrieve the DAV:displayname property of the
members of the two collections (/_acl/users/ and /_acl_groups/). This members of the two collections (/_acl/users/ and /_acl_groups/).
information could be used when displaying a user interface for This information could be used when displaying a user interface for
creating access control entries. creating access control entries.
>> Request << >> Request <<
PROPFIND /papers/ HTTP/1.1 PROPFIND /papers/ HTTP/1.1
Host: www.webdav.org Host: www.webdav.org
Content-type: text/xml; charset="utf-8" Content-type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
Depth: 0 Depth: 0
Authorization: Digest username="yarong", Authorization: Digest username="yarong",
skipping to change at line 1302 skipping to change at line 1398
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D="DAV:"> <D:propfind xmlns:D="DAV:">
<D:prop> <D:prop>
<D:principal-collection-set/> <D:principal-collection-set/>
</D:prop> </D:prop>
</D:propfind> </D:propfind>
>> Response << >> Response <<
Clemm, Hopkins, Sedlar, Whitehead [Page 26]
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"> <D:multistatus xmlns:D="DAV:">
<D:response> <D:response>
<D:href>http://www.webdav.org/papers/</D:href> <D:href>http://www.webdav.org/papers/</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
Clemm, Hopkins, Sedlar, Whitehead [Page 29]
<D:principal-collection-set> <D:principal-collection-set>
<D:href> <D:href>
http://www.webdav.org/_acl/users/ http://www.webdav.org/_acl/users/
</D:href> </D:href>
<D:href> <D:href>
http://www.webdav.org/_acl/groups/ http://www.webdav.org/_acl/groups/
</D:href> </D:href>
</D:principal-collection-set> </D:principal-collection-set>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
5.7 Example: PROPFIND to retrieve access control properties 5.8 Example: PROPFIND to retrieve access control properties
The following example shows how access control information can be The following example shows how access control information can be
retrieved by using the PROPFIND method to fetch the values of the retrieved by using the PROPFIND method to fetch the values of the
DAV:owner, DAV:supported-privilege-set, DAV:current-user-privilege- DAV:owner, DAV:supported-privilege-set, DAV:current-user-privilege-
set, and DAV:acl properties. set, and DAV:acl properties.
>> Request << >> Request <<
PROPFIND /top/container/ HTTP/1.1 PROPFIND /top/container/ HTTP/1.1
Host: www.foo.org Host: www.foo.org
skipping to change at line 1353 skipping to change at line 1450
uri="/top/container/", response="...", opaque="..." uri="/top/container/", response="...", opaque="..."
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:propfind xmlns:D="DAV:"> <D:propfind xmlns:D="DAV:">
<D:prop> <D:prop>
<D:owner/> <D:owner/>
<D:supported-privilege-set/> <D:supported-privilege-set/>
<D:current-user-privilege-set/> <D:current-user-privilege-set/>
<D:acl/> <D:acl/>
</D:prop> </D:prop>
Clemm, Hopkins, Sedlar, Whitehead [Page 27]
</D:propfind> </D:propfind>
>> Response << >> Response <<
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
Clemm, Hopkins, Sedlar, Whitehead [Page 30]
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:multistatus <D:multistatus
xmlns:D="DAV:" xmlns:D="DAV:"
xmlns:A="http://www.webdav.org/acl/"> <D:response> xmlns:A="http://www.webdav.org/acl/"> <D:response>
<D:href>http://www.foo.org/top/container/</D:href> <D:href>http://www.foo.org/top/container/</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<D:owner> <D:owner>
<D:href>http://www.foo.org/users/gclemm</D:href> </D:owner> <D:href>http://www.foo.org/users/gclemm</D:href>
</D:owner>
<D:supported-privilege-set> <D:supported-privilege-set>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:all/> </D:privilege> <D:privilege> <D:all/> </D:privilege>
<D:abstract/> <D:abstract/>
<D:description xml:lang="en">Any operation</D:description> <D:description xml:lang="en">Any
operation</D:description>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:read/> </D:privilege> <D:privilege> <D:read/> </D:privilege>
<D:description xml:lang="en">Read any <D:description xml:lang="en">Read any
object</D:description> object</D:description>
</D:supported-privilege> </D:supported-privilege>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:write/> </D:privilege> <D:privilege> <D:write/> </D:privilege>
<D:abstract/> <D:abstract/>
<D:description xml:lang="en">Write any <D:description xml:lang="en">Write any
object</D:description> object</D:description>
skipping to change at line 1405 skipping to change at line 1503
object</D:description> object</D:description>
</D:supported-privilege> </D:supported-privilege>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <A:delete/> </D:privilege> <D:privilege> <A:delete/> </D:privilege>
<D:description xml:lang="en">Delete an <D:description xml:lang="en">Delete an
object</D:description> object</D:description>
</D:supported-privilege> </D:supported-privilege>
</D:supported-privilege> </D:supported-privilege>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:read-acl/> </D:privilege> <D:privilege> <D:read-acl/> </D:privilege>
<D:description xml:lang="en">Read the ACL</D:description> <D:description xml:lang="en">Read the
ACL</D:description>
Clemm, Hopkins, Sedlar, Whitehead [Page 28]
</D:supported-privilege> </D:supported-privilege>
<D:supported-privilege> <D:supported-privilege>
Clemm, Hopkins, Sedlar, Whitehead [Page 31]
<D:privilege> <D:write-acl/> </D:privilege> <D:privilege> <D:write-acl/> </D:privilege>
<D:description xml:lang="en">Write the <D:description xml:lang="en">Write the
ACL</D:description> ACL</D:description>
</D:supported-privilege> </D:supported-privilege>
</D:supported-privilege> </D:supported-privilege>
</D:supported-privilege-set> </D:supported-privilege-set>
<D:current-user-privilege-set> <D:current-user-privilege-set>
<D:privilege> <D:read/> </D:privilege> <D:privilege> <D:read/> </D:privilege>
<D:privilege> <D:read-acl/> </D:privilege> <D:privilege> <D:read-acl/> </D:privilege>
</D:current-user-privilege-set> </D:current-user-privilege-set>
skipping to change at line 1449 skipping to change at line 1548
<D:property> <D:owner/> </D:property> </D:principal> <D:property> <D:owner/> </D:property> </D:principal>
<D:grant> <D:grant>
<D:privilege> <D:read-acl/> </D:privilege> <D:privilege> <D:read-acl/> </D:privilege>
<D:privilege> <D:write-acl/> </D:privilege> </D:grant> <D:privilege> <D:write-acl/> </D:privilege> </D:grant>
</D:ace> </D:ace>
<D:ace> <D:ace>
<D:principal> <D:all/> </D:principal> <D:principal> <D:all/> </D:principal>
<D:grant> <D:grant>
<D:privilege> <D:read/> </D:privilege></D:grant> <D:privilege> <D:read/> </D:privilege></D:grant>
<D:inherited> <D:inherited>
<D:href>http://www.foo.org/top/</D:href> </D:inherited> <D:href>http://www.foo.org/top/</D:href>
</D:inherited>
</D:ace> </D:acl> </D:ace> </D:acl>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:response> </D:multistatus> </D:propstat> </D:response> </D:multistatus>
The value of the DAV:owner property is a single DAV:href XML element Clemm, Hopkins, Sedlar, Whitehead [Page 32]
containing the URL of the principal that owns this resource. The value of the DAV:owner property is a single DAV:href XML
element containing the URL of the principal that owns this
resource.
Clemm, Hopkins, Sedlar, Whitehead [Page 29]
The value of the DAV:supported-privilege-set property is a tree of The value of the DAV:supported-privilege-set property is a tree of
supported privileges: supported privileges (using "[XML Namespace , localname]" to
identify each privilege):
DAV:all (aggregate, abstract) [DAV:, all] (aggregate, abstract)
| |
+-- DAV:read +-- [DAV:, read]
+-- DAV:write (aggregate, abstract) +-- [DAV:, write] (aggregate, abstract)
| |
+-- http://www.webdav.org/acl/create +-- [http://www.webdav.org/acl/, create]
+-- http://www.webdav.org/acl/update +-- [http://www.webdav.org/acl/, update]
+-- http://www.webdav.org/acl/delete +-- [http://www.webdav.org/acl/, delete]
+-- DAV:read-acl +-- [DAV:, read-acl]
+-- DAV:write-acl +-- [DAV:, write-acl]
The DAV:current-user-privilege-set property contains two privileges, The DAV:current-user-privilege-set property contains two
DAV:read, and DAV:read-acl. This indicates that the current privileges, DAV:read, and DAV:read-acl. This indicates that the
authenticated user only has the ability to read the resource, and current authenticated user only has the ability to read the
read the DAV:acl property on the resource. resource, and read the DAV:acl property on the resource.
The DAV:acl property contains a set of four ACEs: The DAV:acl property contains a set of four ACEs:
ACE #1: The principal identified by the URL ACE #1: The principal identified by the URL
http://www.foo.org/users/esedlar is granted the DAV:read, DAV:write, http://www.foo.org/users/esedlar is granted the DAV:read,
and DAV:read-acl privileges. DAV:write, and DAV:read-acl privileges.
ACE #2: The principals identified by the URL ACE #2: The principals identified by the URL
http://www.foo.org/groups/marketing/ are denied the DAV:read http://www.foo.org/groups/marketing/ are denied the DAV:read
privilege. In this example, the principal URL identifies a group, privilege. In this example, the principal URL identifies a group.
which is represented by a collection principal.
ACE #3: In this ACE, the principal is a property principal, ACE #3: In this ACE, the principal is a property principal,
specifically the DAV:owner property. When evaluating this ACE, the specifically the DAV:owner property. When evaluating this ACE, the
value of the DAV:owner property is retrieved, and is examined to see value of the DAV:owner property is retrieved, and is examined to
if it contains a DAV:href XML element. If so, the URL within the see if it contains a DAV:href XML element. If so, the URL within
DAV:href element is read, and identifies a principal. In this ACE, the DAV:href element is read, and identifies a principal. In this
the owner is granted DAV:read-acl, and DAV:write-acl privileges. ACE, the owner is granted DAV:read-acl, and DAV:write-acl
privileges.
ACE #4: This ACE grants the DAV:all principal (all users) the ACE #4: This ACE grants the DAV:all principal (all users) the
DAV:read privilege. This ACE is inherited from the resource DAV:read privilege. This ACE is inherited from the resource
http://www.foo.org/top/, the parent collection of this resource. http://www.foo.org/top/, the parent collection of this resource.
Clemm, Hopkins, Sedlar, Whitehead [Page 33]
6 ACL SEMANTICS 6 ACL SEMANTICS
The ACL semantics define how multiple ACEs that match the current The ACL semantics define how multiple ACEs that match the current
user are combined, what are the constraints on how ACEs can be user are combined, what are the constraints on how ACEs can be
ordered, and which principals must have an ACE. ordered, and which principals must have an ACE.
<!ELEMENT acl-semantics (ace-combination?, ace-ordering?, allowed- <!ELEMENT acl-semantics (ace-combination?, ace-ordering?,
ace?, required-principal?)> allowed-ace?, required-principal?)>
Clemm, Hopkins, Sedlar, Whitehead [Page 30]
6.1 ACE Combination 6.1 ACE Combination
The DAV:ace-combination element defines how privileges from multiple The DAV:ace-combination element defines how privileges from
ACEs that match the current user will be combined to determine the multiple ACEs that match the current user will be combined to
access privileges for that user. Multiple ACEs may match the same determine the access privileges for that user. Multiple ACEs may
user because the same principal can appear in multiple ACEs, because match the same user because the same principal can appear in
multiple principals can identify the same user, and because one multiple ACEs, because multiple principals can identify the same
principal can be a member of another principal. user, and because one principal can be a member of another
principal.
<!ELEMENT ace-combination <!ELEMENT ace-combination
(first-match | all-grant-before-any-deny | specific-deny- (first-match | all-grant-before-any-deny | specific-deny-
overrides-grant)> overrides-grant)>
6.1.1 DAV:first-match ACE Combination 6.1.1 DAV:first-match ACE Combination
The ACEs are evaluated in the order in which they appear in the ACL. The ACEs are evaluated in the order in which they appear in the
If the first ACE that matches the current user does not grant all the ACL. If the first ACE that matches the current user does not grant
privileges needed for the request, the request MUST fail. all the privileges needed for the request, the request MUST fail.
<!ELEMENT first-match EMPTY> <!ELEMENT first-match EMPTY>
6.1.2 DAV:all-grant-before-any-deny ACE Combination 6.1.2 DAV:all-grant-before-any-deny ACE Combination
The ACEs are evaluated in the order in which they appear in the ACL. The ACEs are evaluated in the order in which they appear in the
If an evaluated ACE denies a privilege needed for the request, the ACL. If an evaluated ACE denies a privilege needed for the
request MUST fail. If all ACEs have been evaluated without the user request, the request MUST fail. If all ACEs have been evaluated
being granted all privileges needed for the request, the request MUST without the user being granted all privileges needed for the
fail. request, the request MUST fail.
<!ELEMENT all-grant-before-any-deny EMPTY> <!ELEMENT all-grant-before-any-deny EMPTY>
6.1.3 DAV:specific-deny-overrides-grant ACE Combination 6.1.3 DAV:specific-deny-overrides-grant ACE Combination
All ACEs in the ACL are evaluated. An "individual ACE" is one whose All ACEs in the ACL are evaluated. An "individual ACE" is one
principal identifies the current user. A "group ACE" is one whose whose principal matches the current user. A "group ACE" is one
principal is a collection that contains a principal that identifies whose principal is a group that has a member that matches the
the current user. A privilege is granted if it is granted by an current user. A privilege is granted if it is granted by an
Clemm, Hopkins, Sedlar, Whitehead [Page 34]
individual ACE and not denied by an individual ACE, or if it is individual ACE and not denied by an individual ACE, or if it is
granted by a group ACE and not denied by an individual or group ACE. granted by a group ACE and not denied by an individual or group
A request MUST fail if any of its needed privileges are not granted. ACE. A request MUST fail if any of its needed privileges are not
granted.
<!ELEMENT specific-deny-overrides-grant EMPTY> <!ELEMENT specific-deny-overrides-grant EMPTY>
6.2 ACE Ordering 6.2 ACE Ordering
The DAV:ace-ordering element defines a constraint on how the ACEs can The DAV:ace-ordering element defines a constraint on how the ACEs
be ordered in the ACL. can be ordered in the ACL.
<!ELEMENT ace-ordering (deny-before-grant)? > <!ELEMENT ace-ordering (deny-before-grant)? >
Clemm, Hopkins, Sedlar, Whitehead [Page 31]
6.2.1 DAV:deny-before-grant ACE Ordering 6.2.1 DAV:deny-before-grant ACE Ordering
This element indicates that all deny ACEs must precede all grant This element indicates that all deny ACEs must precede all grant
ACEs. ACEs.
<!ELEMENT deny-before-grant EMPTY> <!ELEMENT deny-before-grant EMPTY>
6.3 Allowed ACE 6.3 Allowed ACE
The DAV:allowed-ace XML element specifies constraints on what kinds The DAV:allowed-ace XML element specifies constraints on what kinds
of ACEs are allowed in an ACL. of ACEs are allowed in an ACL.
<!ELEMENT allowed-ace (principal-only-one-ace | grant-only)*> <!ELEMENT allowed-ace (principal-only-one-ace | grant-only |
no-invert | no-acl-inherit)*>
6.3.1 DAV:principal-only-one-ace ACE Constraint 6.3.1 DAV:principal-only-one-ace ACE Constraint
This element indicates that a principal can appear in only one ACE This element indicates that a principal can appear in only one ACE
per resource. per resource.
<!ELEMENT principal-only-one-ace EMPTY> <!ELEMENT principal-only-one-ace EMPTY>
6.3.2 DAV:grant-only ACE Constraint 6.3.2 DAV:grant-only ACE Constraint
This element indicates that ACEs with deny clauses are not allowed. This element indicates that ACEs with deny clauses are not allowed.
<!ELEMENT grant-only EMPTY> <!ELEMENT grant-only EMPTY>
6.3.3 DAV:no-invert ACE Constraint
This element indicates that ACEs with the <invert> element are not
allowed.
<!ELEMENT no-invert EMPTY>
Clemm, Hopkins, Sedlar, Whitehead [Page 35]
6.3.4 DAV:no-acl-inherit ACE Constraint
This element indicates that ACLs with the <inherited-acl> element
are not allowed.
<!ELEMENT no-acl-inherit EMPTY>
6.4 Required Principals 6.4 Required Principals
The required principal elements identify which principals must have The required principal elements identify which principals must have
an ACE defined in the ACL. an ACE defined in the ACL.
<!ELEMENT required-principal <!ELEMENT required-principal
(all? | authenticated? | unauthenticated? | self? | href* | (all? | authenticated? | unauthenticated? | self? | href* |
property*)> property*)>
For example, the following element requires that the ACL contain a For example, the following element requires that the ACL contain a
skipping to change at line 1611 skipping to change at line 1730
<D:required-principal xmlns:D="DAV:"> <D:required-principal xmlns:D="DAV:">
<D:property> <D:owner/> </D:property> <D:property> <D:owner/> </D:property>
</D:required-principal> </D:required-principal>
7 ACCESS CONTROL AND EXISTING METHODS 7 ACCESS CONTROL AND EXISTING METHODS
This section defines the impact of access control functionality on This section defines the impact of access control functionality on
existing methods. existing methods.
Clemm, Hopkins, Sedlar, Whitehead [Page 32]
7.1 OPTIONS 7.1 OPTIONS
If the server supports access control, it MUST return "access- If the server supports access control, it MUST return "access-
control" as a field in the DAV response header from an OPTIONS control" as a field in the DAV response header from an OPTIONS
request on any resource implemented by that server. request on any resource implemented by that server.
7.1.1 Example - OPTIONS 7.1.1 Example - OPTIONS
>> Request << >> Request <<
OPTIONS /foo.html HTTP/1.1 OPTIONS /foo.html HTTP/1.1
Host: www.webdav.org Host: www.webdav.org
Content-Length: 0 Content-Length: 0
>> Response << >> Response <<
HTTP/1.1 200 OK HTTP/1.1 200 OK
DAV: 1, 2, access-control DAV: 1, 2, access-control
Allow: OPTIONS, GET, PUT, PROPFIND, PROPPATCH, ACL Allow: OPTIONS, GET, PUT, PROPFIND, PROPPATCH, ACL
Clemm, Hopkins, Sedlar, Whitehead [Page 36]
In this example, the OPTIONS response indicates that the server In this example, the OPTIONS response indicates that the server
supports access control and that /foo.html can have its access supports access control and that /foo.html can have its access
control list modified by the ACL method. control list modified by the ACL method.
7.2 MOVE 7.2 MOVE
When a resource is moved from one location to another due to a MOVE When a resource is moved from one location to another due to a MOVE
request, the non-inherited and non-protected ACEs in the DAV:acl request, the non-inherited and non-protected ACEs in the DAV:acl
property of the resource MUST NOT be modified, or the MOVE request property of the resource MUST NOT be modified, or the MOVE request
fails. Handling of inherited and protected ACEs is intentionally fails. Handling of inherited and protected ACEs is intentionally
undefined to give server implementations flexibility in how they undefined to give server implementations flexibility in how they
implement ACE inheritance and protection. implement ACE inheritance and protection.
7.3 COPY 7.3 COPY
The DAV:acl property on the resource at the destination of a COPY The DAV:acl property on the resource at the destination of a COPY
MUST be the same as if the resource was created by an individual MUST be the same as if the resource was created by an individual
resource creation request (e.g. MKCOL, PUT). Clients wishing to resource creation request (e.g. MKCOL, PUT). Clients wishing to
preserve the DAV:acl property across a copy need to read the DAV:acl preserve the DAV:acl property across a copy need to read the
property prior to the COPY, then perform an ACL operation on the new DAV:acl property prior to the COPY, then perform an ACL operation
resource at the destination to restore, insofar as this is possible, on the new resource at the destination to restore, insofar as this
the original access control list. is possible, the original access control list.
7.4 DELETE 7.4 DELETE
The precise combination of privileges and resources necessary to The precise combination of privileges and resources necessary to
permit the DELETE method is intentionally left to the discretion of permit the DELETE method is intentionally left to the discretion of
each server implementation. It is envisioned that on some servers, each server implementation. It is envisioned that on some servers,
DELETE will require write permission on the collection containing the DELETE will require write permission on the collection containing
resource to be deleted. On other servers, it might also require the resource to be deleted. On other servers, it might also
write permission on the resource being deleted. require write permission on the resource being deleted.
Clemm, Hopkins, Sedlar, Whitehead [Page 33]
7.5 LOCK 7.5 LOCK
A lock on a resource ensures that only the lock owner can modify ACEs A lock on a resource ensures that only the lock owner can modify
that are not inherited and not protected (these are the only ACEs ACEs that are not inherited and not protected (these are the only
that a client can modify with an ACL request). A lock does not ACEs that a client can modify with an ACL request). A lock does not
protect inherited or protected ACEs, since a client cannot modify protect inherited or protected ACEs, since a client cannot modify
them with an ACL request on that resource. them with an ACL request on that resource.
8 ACCESS CONTROL METHODS 8 ACCESS CONTROL METHODS
8.1 ACL 8.1 ACL
The ACL method modifies the access control list (which can be read The ACL method modifies the access control list (which can be read
via the DAV:acl property) of a resource. Specifically, the ACL via the DAV:acl property) of a resource. Specifically, the ACL
method only permits modification to ACEs that are not inherited, and method only permits modification to ACEs that are not inherited,
are not protected. An ACL method invocation modifies all non- and are not protected. An ACL method invocation modifies all non-
inherited and non-protected ACEs in a resourceĂs access control list
to exactly match the ACEs contained within in the DAV:acl XML element Clemm, Hopkins, Sedlar, Whitehead [Page 37]
(specified in Section 5.4) of the request body. An ACL request body inherited and non-protected ACEs in a resource's access control
MUST contain only one DAV:acl XML element. Unless the non-inherited list to exactly match the ACEs contained within in the DAV:acl XML
and non-protected ACEs of the DAV:acl property of the resource can be element (specified in Section 5.4) of the request body. An ACL
updated to be exactly the value specified in the ACL request, the ACL request body MUST contain only one DAV:acl XML element. Unless the
request MUST fail. non-inherited and non-protected ACEs of the DAV:acl property of the
resource can be updated to be exactly the value specified in the
ACL request, the ACL request MUST fail.
It is possible that the ACEs visible to the current user in the It is possible that the ACEs visible to the current user in the
DAV:acl property may only be a portion of the complete set of ACEs on DAV:acl property may only be a portion of the complete set of ACEs
that resource. If this is the case, an ACL request only modifies the on that resource. If this is the case, an ACL request only modifies
set of ACEs visible to the current user, and does not affect any non- the set of ACEs visible to the current user, and does not affect
visible ACE. any non-visible ACE.
In order to avoid overwriting DAV:acl changes by another client, a In order to avoid overwriting DAV:acl changes by another client, a
client SHOULD acquire a WebDAV lock on the resource before retrieving client SHOULD acquire a WebDAV lock on the resource before
the DAV:acl property of a resource that it intends on updating. retrieving the DAV:acl property of a resource that it intends on
updating.
Implementation Note: Two common operations are to add or remove an Implementation Note: Two common operations are to add or remove
ACE from an existing access control list. To accomplish this, a an ACE from an existing access control list. To accomplish this,
client uses the PROPFIND method to retrieve the value of the a client uses the PROPFIND method to retrieve the value of the
DAV:acl property, then parses the returned access control list to DAV:acl property, then parses the returned access control list
remove all inherited and protected ACEs (these ACEs are tagged to remove all inherited and protected ACEs (these ACEs are
with the DAV:inherited and DAV:protected XML elements). In the tagged with the DAV:inherited and DAV:protected XML elements).
remaining set of non-inherited, non-protected ACEs, the client can In the remaining set of non-inherited, non-protected ACEs, the
add or remove one or more ACEs before submitting the final ACE set client can add or remove one or more ACEs before submitting the
in the request body of the ACL method. final ACE set in the request body of the ACL method.
8.1.1 ACL Preconditions 8.1.1 ACL Preconditions
An implementation MAY enforce one or more of the following An implementation MAY enforce one or more of the following
constraints on an ACL request. If the constraint is violated, a 403 constraints on an ACL request. If the constraint is violated, a
(Forbidden) response MUST be returned and the indicated XML element 403 (Forbidden) or 409 (Conflict) response MUST be returned and the
MUST be returned as the top level element in an XML response body. indicated XML element MUST be returned as a child of a top level
DAV:error element in an XML response body.
Clemm, Hopkins, Sedlar, Whitehead [Page 34] (DAV:no-ace-conflict): The ACEs submitted in the ACL request MUST
<DAV:ace-conflict/>: A conflict exists between two or more ACEs NOT conflict with each other. What is considered a conflict
submitted in the ACL request. depends on the ACL semantics of that resource.
<DAV:protected-ace-conflict/>: A conflict exists between an ACE in (DAV:no-protected-ace-conflict): The ACEs submitted in the ACL
the ACL request and a protected ACE on the resource. For example, if request MUST NOT conflict with the protected ACEs on the resource.
the resource has a protected ACE granting DAV:write to a given For example, if the resource has a protected ACE granting DAV:write
principal, then it would be a protected ACE conflict if the ACL to a given principal, then it would not be consistent if the ACL
request submitted an ACE denying DAV:write to the same principal. request submitted an ACE denying DAV:write to the same principal.
<DAV:inherited-ace-conflict/>: A conflict exists between an ACE in (DAV:no-inherited-ace-conflict): The ACEs submitted in the ACL
the ACL request and an inherited ACE on the resource. For example, if request MUST NOT conflict with the inherited ACEs on the resource.
the resource inherits an ACE from its parent collection granting
DAV:write to a given principal, then it would be an inherited ACE
conflict if the ACL request submitted an ACE denying DAV:write to the
same principal. Note that reporting of this error will be
implementation-dependent. Implementations have the choice to either
report this error, or to allow the ACE to be set, and then let normal
ACE evaluation rules determine whether the new ACE has any impact on
the privileges available to a specific principal.
<DAV:too-many-aces/>: An implementation MAY limit the number of ACEs Clemm, Hopkins, Sedlar, Whitehead [Page 38]
in an ACL. However, ACL-compliant servers MUST support at least one For example, if the resource inherits an ACE from its parent
collection granting DAV:write to a given principal, then it would
not be consistent if the ACL request submitted an ACE denying
DAV:write to the same principal. Note that reporting of this error
will be implementation-dependent. Implementations have the choice
to either report this error, or to allow the ACE to be set, and
then let normal ACE evaluation rules determine whether the new ACE
has any impact on the privileges available to a specific principal.
(DAV:limited-number-of-aces): The number of ACEs submitted in the
ACL request MUST NOT exceed the number of ACEs allowed on that
resource. However, ACL-compliant servers MUST support at least one
ACE granting privileges to a single principal, and one ACE granting ACE granting privileges to a single principal, and one ACE granting
privileges to a collection principal. privileges to a group.
<DAV:deny-before-grant/>: All non-inherited deny ACEs MUST precede (DAV:deny-before-grant): All non-inherited deny ACEs MUST precede
all non-inherited grant ACEs. all non-inherited grant ACEs.
<DAV:principal-only-one-ace/>: For implementations that have the (DAV:principal-only-one-ace): The ACL request MUST NOT result in
DAV:principal-only-one-ace constraint (defined in Section 6.3.1), more than one ACE for a given principal. This precondition applies
this XML element indicates that fulfilling the ACL request would only when the ACL semantics of the resource includes the
result in multiple ACEs for one or more principals. DAV:principal-only-one-ace constraint (defined in Section 6.3.1).
<DAV:grant-only/>: For implementations that have the DAV:grant-only (DAV:grant-only): The ACEs submitted in the ACL request MUST NOT
constraint (defined in Section 6.3.2), this XML element indicates the include a deny ACE. This precondition applies only when the ACL
request contained one or more deny ACEs. semantics of the resource includes the DAV:grant-only constraint
(defined in Section 6.3.2).
<DAV:no-abstract/>: The ACL request attempts to set an abstract (DAV:no-invert): The ACL request MUST NOT include a <dav:invert>
privilege in an ACE (see Section 5.2). element. This precondition applies only when the ACL semantics of
the resource includes the DAV:no-invert constraint (defined in
Section 6.3.4).
<DAV:supported-privilege/>: One or more of the privileges in the ACL (DAV:no-acl-inherit): The ACL request MUST NOT include a
request is not supported by the resource. <dav:inherited-acl> element. This precondition applies only when
the ACL semantics of the resource includes the DAV:no-acl-inherit
constraint (defined in Section 6.3.4).
<DAV:required-principal/>: One or more required principals (see (DAV:no-abstract): The ACL request MUST NOT attempt to grant or
Section 6.4) would not be present in the access control list after deny an abstract privilege (see Section 5.2).
processing the ACL request. The DAV:required-principal XML element
MUST contain a list of the missing principal(s), following the syntax
specified in Section 6.4.
<DAV:recognized-principal/>: One or more of the principal URLs in the (DAV:not-supported-privilege): The ACEs submitted in the ACL
ACL request does not identify a principal resource. request MUST be supported by the resource.
Clemm, Hopkins, Sedlar, Whitehead [Page 35] (DAV:missing-required-principal): The result of the ACL request
<DAV:allowed-principal/>: One or more of the principal URLs in the MUST have at least one ACE for each principal identified in a
ACL request is not allowed in an ACE. For example, a server where DAV:required-principal XML element in the ACL semantics of that
only authenticated principals can access resources would not allow resource (see Section 6.3.2).
the DAV:all or DAV:unauthenticated principals to be used in an ACE,
since these would allow unauthenticated access to resources. Clemm, Hopkins, Sedlar, Whitehead [Page 39]
(DAV:recognized-principal): Every principal URL in the ACL request
MUST identify a principal resource.
(DAV:allowed-principal): The principals specified in the ACEs
submitted in the ACL request MUST be allowed as principals for the
resource. For example, a server where only authenticated principals
can access resources would not allow the DAV:all or
DAV:unauthenticated principals to be used in an ACE, since these
would allow unauthenticated access to resources.
8.1.2 Example: the ACL method 8.1.2 Example: the ACL method
In the following example, user "fielding", authenticated by In the following example, user "fielding", authenticated by
information in the Authorization header, grants the principal information in the Authorization header, grants the principal
identified by the URL http://www.foo.org/users/esedlar (i.e., the identified by the URL http://www.foo.org/users/esedlar (i.e., the
user "esedlar") read and write privileges, grants the owner of the user "esedlar") read and write privileges, grants the owner of the
resource read-acl and write-acl privileges, and grants everyone read resource read-acl and write-acl privileges, and grants everyone
privileges. read privileges.
>> Request << >> Request <<
ACL /top/container/ HTTP/1.1 ACL /top/container/ HTTP/1.1
Host: www.foo.org Host: www.foo.org
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx Content-Length: xxxx
Authorization: Digest username="fielding", Authorization: Digest username="fielding",
realm="users@foo.org", nonce="...", realm="users@foo.org", nonce="...",
uri="/top/container/", response="...", opaque="..." uri="/top/container/", response="...", opaque="..."
skipping to change at line 1816 skipping to change at line 1950
</D:grant> </D:grant>
</D:ace> </D:ace>
<D:ace> <D:ace>
<D:principal> <D:principal>
<D:property> <D:owner/> </D:property> <D:property> <D:owner/> </D:property>
</D:principal> </D:principal>
<D:grant> <D:grant>
<D:privilege> <D:read-acl/> </D:privilege> <D:privilege> <D:read-acl/> </D:privilege>
<D:privilege> <D:write-acl/> </D:privilege> <D:privilege> <D:write-acl/> </D:privilege>
</D:grant> </D:grant>
Clemm, Hopkins, Sedlar, Whitehead [Page 40]
</D:ace> </D:ace>
<D:ace> <D:ace>
<D:principal> <D:all/> </D:principal> <D:principal> <D:all/> </D:principal>
<D:grant> <D:grant>
<D:privilege> <D:read/> </D:privilege> <D:privilege> <D:read/> </D:privilege>
</D:grant> </D:grant>
</D:ace> </D:ace> </D:acl>
Clemm, Hopkins, Sedlar, Whitehead [Page 36]
</D:acl>
>> Response << >> Response <<
HTTP/1.1 200 OK HTTP/1.1 200 OK
8.1.3 Example: ACL method failure due to protected ACE conflict 8.1.3 Example: ACL method failure due to protected ACE conflict
In the following request, user "fielding", authenticated by In the following request, user "fielding", authenticated by
information in the Authorization header, attempts to deny the information in the Authorization header, attempts to deny the
principal identified by the URL http://www.foo.org/users/esedlar principal identified by the URL http://www.foo.org/users/esedlar
(i.e., the user "esedlar") write privileges. Prior to the request, (i.e., the user "esedlar") write privileges. Prior to the request,
the DAV:acl property on the resource contained a protected ACE (see the DAV:acl property on the resource contained a protected ACE (see
Section 5.4.3) granting DAV:owner the DAV:read and DAV:write Section 5.4.3) granting DAV:owner the DAV:read and DAV:write
privileges. The principal identified by URL privileges. The principal identified by URL
http://www.foo.org/users/esedlar is the owner of the resource. The http://www.foo.org/users/esedlar is the owner of the resource. The
ACL method invocation fails because the submitted ACE conflicts with ACL method invocation fails because the submitted ACE conflicts
the protected ACE, thus violating the semantics of ACE protection. with the protected ACE, thus violating the semantics of ACE
protection.
>> Request << >> Request <<
ACL /top/container/ HTTP/1.1 ACL /top/container/ HTTP/1.1
Host: www.foo.org Host: www.foo.org
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx Content-Length: xxxx
Authorization: Digest username="fielding", Authorization: Digest username="fielding",
realm="users@foo.org", nonce="...", realm="users@foo.org", nonce="...",
uri="/top/container/", response="...", opaque="..." uri="/top/container/", response="...", opaque="..."
skipping to change at line 1866 skipping to change at line 2000
<D:ace> <D:ace>
<D:principal> <D:principal>
<D:href>http://www.foo.org/users/esedlar</D:href> <D:href>http://www.foo.org/users/esedlar</D:href>
</D:principal> </D:principal>
<D:deny> <D:deny>
<D:privilege> <D:write/> </D:privilege> <D:privilege> <D:write/> </D:privilege>
</D:deny> </D:deny>
</D:ace> </D:ace>
</D:acl> </D:acl>
Clemm, Hopkins, Sedlar, Whitehead [Page 41]
>> Response << >> Response <<
HTTP/1.1 403 Forbidden HTTP/1.1 403 Forbidden
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:protected-ace-conflict xmlns:D="DAV:"/> <D:error xmlns:D="DAV:">
<D:no-protected-ace-conflict/>
Clemm, Hopkins, Sedlar, Whitehead [Page 37] </D:error>
8.1.4 Example: ACL method failure due to an inherited ACE conflict 8.1.4 Example: ACL method failure due to an inherited ACE conflict
In the following request, user "ejw", authenticated by information in In the following request, user "ejw", authenticated by information
the Authorization header, tries to change the access control list on in the Authorization header, tries to change the access control
the resource http://www.foo.org/top/index.html. This resource has two list on the resource http://www.foo.org/top/index.html. This
inherited ACEs. resource has two inherited ACEs.
Inherited ACE #1 grants the principal identified by URL Inherited ACE #1 grants the principal identified by URL
http://www.foo.org/users/ejw (i.e., the user "ejw") http://www.foo.org/users/ejw (i.e., the user "ejw")
http://www.foo.org/privs/write-all and DAV:read-acl privileges. On http://www.foo.org/privs/write-all and DAV:read-acl privileges. On
this server, http://www.foo.org/privs/write-all is an aggregate this server, http://www.foo.org/privs/write-all is an aggregate
privilege containing DAV:write, and DAV:write-acl. privilege containing DAV:write, and DAV:write-acl.
Inherited ACE #2 grants principal DAV:all the DAV:read privilege. Inherited ACE #2 grants principal DAV:all the DAV:read privilege.
The request attempts to set a (non-inherited) ACE, denying the The request attempts to set a (non-inherited) ACE, denying the
principal identified by the URL http://www.foo.org/users/ejw (i.e., principal identified by the URL http://www.foo.org/users/ejw (i.e.,
the user ˘ejw") DAV:write permission. This conflicts with inherited the user "ejw") DAV:write permission. This conflicts with inherited
ACE #1. Note that the decision to report an inherited ACE conflict is ACE #1. Note that the decision to report an inherited ACE conflict
specific to this server implementation. Another server implementation is specific to this server implementation. Another server
could have allowed the new ACE to be set, and then used normal ACE implementation could have allowed the new ACE to be set, and then
evaluation rules to determine whether the new ACE has any impact on used normal ACE evaluation rules to determine whether the new ACE
the privileges available to a principal. has any impact on the privileges available to a principal.
>> Request << >> Request <<
ACL /top/index.html HTTP/1.1 ACL /top/index.html HTTP/1.1
Host: www.foo.org Host: www.foo.org
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx Content-Length: xxxx
Authorization: Digest username="ejw", Authorization: Digest username="ejw",
realm="users@foo.org", nonce="...", realm="users@foo.org", nonce="...",
uri="/top/index.html", response="...", opaque="..." uri="/top/index.html", response="...", opaque="..."
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:acl xmlns:D="DAV:" xmlns:F="http://www.foo.org/privs/"> <D:acl xmlns:D="DAV:" xmlns:F="http://www.foo.org/privs/">
<D:ace> <D:ace>
Clemm, Hopkins, Sedlar, Whitehead [Page 42]
<D:principal> <D:principal>
<D:href>http://www.foo.org/users/ejw</D:href> <D:href>http://www.foo.org/users/ejw</D:href>
</D:principal> </D:principal>
<D:grant><D:write/></D:grant> <D:grant><D:write/></D:grant>
</D:ace> </D:ace>
</D:acl> </D:acl>
>> Response << >> Response <<
HTTP/1.1 403 Forbidden HTTP/1.1 403 Forbidden
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:error xmlns:D="DAV:">
Clemm, Hopkins, Sedlar, Whitehead [Page 38] <D:no-inherited-ace-conflict xmlns:D="DAV:"/>
<D:inherited-ace-conflict xmlns:D="DAV:"/> </D:error>
8.1.5 Example: ACL method failure due to an attempt to set grant and 8.1.5 Example: ACL method failure due to an attempt to set grant and
deny in a single ACE. deny in a single ACE.
In this example, user "ygoland", authenticated by information in the In this example, user "ygoland", authenticated by information in
Authorization header, tries to change the access control list on the the Authorization header, tries to change the access control list
resource http://www.foo.org/diamond/engagement-ring.gif. The ACL on the resource http://www.foo.org/diamond/engagement-ring.gif. The
request includes a single, syntactically and semantically incorrect ACL request includes a single, syntactically and semantically
ACE, which attempts to grant the collection principal identified by incorrect ACE, which attempts to grant the group identified by the
the URL http://www.foo.org/users/friends/ DAV:read privilege and deny URL http://www.foo.org/users/friends/ DAV:read privilege and deny
the principal identified by URL http://www.foo.org/users/ygoland-so the principal identified by URL http://www.foo.org/users/ygoland-so
(i.e., the user "ygoland-so") DAV:read privilege. However, it is (i.e., the user "ygoland-so") DAV:read privilege. However, it is
illegal to have multiple principal elements, as well as both a grant illegal to have multiple principal elements, as well as both a
and deny element in the same ACE, so the request fails due to poor grant and deny element in the same ACE, so the request fails due to
syntax. poor syntax.
>> Request << >> Request <<
ACL /diamond/engagement-ring.gif HTTP/1.1 ACL /diamond/engagement-ring.gif HTTP/1.1
Host: www.foo.org Host: www.foo.org
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx Content-Length: xxxx
Authorization: Digest username="ygoland", Authorization: Digest username="ygoland",
realm="users@foo.org", nonce="...", realm="users@foo.org", nonce="...",
uri="/diamond/engagement-ring.gif", response="...", opaque="..." uri="/diamond/engagement-ring.gif", response="...",
opaque="..."
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:acl xmlns:D="DAV:"> <D:acl xmlns:D="DAV:">
<D:ace> <D:ace>
<D:principal> <D:principal>
Clemm, Hopkins, Sedlar, Whitehead [Page 43]
<D:href>http://www.foo.org/users/friends/</D:href> <D:href>http://www.foo.org/users/friends/</D:href>
</D:principal> </D:principal>
<D:grant><D:read/></D:grant> <D:grant><D:read/></D:grant>
<D:principal> <D:principal>
<D:href>http://www.foo.org/users/ygoland-so</D:href> <D:href>http://www.foo.org/users/ygoland-so</D:href>
</D:principal> </D:principal>
<D:deny><D:read/></D:deny> <D:deny><D:read/></D:deny>
</D:ace> </D:ace>
</D:acl> </D:acl>
>> Response << >> Response <<
HTTP/1.1 400 Bad Request HTTP/1.1 400 Bad Request
Content-Length: 0 Content-Length: 0
Note that if the request had been divided into two ACEs, one to Note that if the request had been divided into two ACEs, one to
grant, and one to deny, the request would have been syntactically grant, and one to deny, the request would have been syntactically
well formed. well formed.
Clemm, Hopkins, Sedlar, Whitehead [Page 39]
9 ACCESS CONTROL REPORTS 9 ACCESS CONTROL REPORTS
9.1 REPORT Method 9.1 REPORT Method
The REPORT method (defined in Section 3.6 of [RFCxxxx]) provides an The REPORT method (defined in Section 3.6 of [RFC3253]) provides an
extensible mechanism for obtaining information about a resource. extensible mechanism for obtaining information about a resource.
Unlike the PROPFIND method, which returns the value of one or more Unlike the PROPFIND method, which returns the value of one or more
named properties, the REPORT method can involve more complex named properties, the REPORT method can involve more complex
processing. REPORT is valuable in cases where the server has access processing. REPORT is valuable in cases where the server has access
to all of the information needed to perform the complex request (such to all of the information needed to perform the complex request
as a query), and where it would require multiple requests for the (such as a query), and where it would require multiple requests for
client to retrieve the information needed to perform the same the client to retrieve the information needed to perform the same
request. request.
9.2 DAV:acl-principal-props Report 9.2 DAV:acl-principal-prop-set Report
The DAV:acl-principle-props report returns, for all principals in the The DAV:acl-principal-prop-set report returns, for all principals
DAV:acl property that are identified by http(s) URLs, the value of in the DAV:acl property that are identified by http(s) URLs or by a
the properties specified in the REPORT request body. In the case DAV:property principal, the value of the properties specified in
where a principal URL appears multiple times, the DAV:acl-principal- the REPORT request body. In the case where a principal URL appears
props report MUST return the properties for that principal only once. multiple times, the DAV:acl-principal-prop-set report MUST return
the properties for that principal only once.
Marshalling Marshalling
The request body MUST be a DAV:acl-principal-props XML element. The request body MUST be a DAV:acl-principal-prop-set XML element.
<!ELEMENT acl-principal-props ANY> <!ELEMENT acl-principal-prop-set ANY>
Clemm, Hopkins, Sedlar, Whitehead [Page 44]
ANY value: a sequence of one or more elements, with at most one ANY value: a sequence of one or more elements, with at most one
DAV:prop element. DAV:prop element.
prop: see RFC 2518, Section 12.11 prop: see RFC 2518, Section 12.11
The response body for a successful request MUST be a DAV:multistatus The response body for a successful request MUST be a
XML element (i.e., the response uses the same format as the response DAV:multistatus XML element (i.e., the response uses the same
for PROPFIND). format as the response for PROPFIND).
multistatus: see RFC 2518, Section 12.9 multistatus: see RFC 2518, Section 12.9
The response body for a successful DAV:acl-principal-props REPORT The response body for a successful DAV:acl-principal-prop-set
request MUST contain a DAV:response element for each principal REPORT request MUST contain a DAV:response element for each
identified by an http(s) URL listed in a DAV:principal XML element of principal identified by an http(s) URL listed in a DAV:principal
an ACE within the DAV:acl property of the resource identified by the XML element of an ACE within the DAV:acl property of the resource
Request-URI. identified by the Request-URI.
9.2.1 Example: DAV:acl-principal-props Report 9.2.1 Example: DAV:acl-principal-prop-set Report
Resource http://www.webdav.org/index.html has an ACL with three ACEs: Resource http://www.webdav.org/index.html has an ACL with three
ACEs:
ACE #1: All principals (DAV:all) have DAV:read and DAV:read-current- ACE #1: All principals (DAV:all) have DAV:read and DAV:read-
user-privilege-set access. current-user-privilege-set access.
Clemm, Hopkins, Sedlar, Whitehead [Page 40]
ACE #2: The principal identified by ACE #2: The principal identified by
http://www.webdav.org/people/gstein (the user ˘gstein") is granted http://www.webdav.org/people/gstein (the user "gstein") is granted
DAV:write, DAV:write-acl, DAV:read-acl privileges. DAV:write, DAV:write-acl, DAV:read-acl privileges.
ACE #3: The collection principal identified by ACE #3: The group identified by
http://www.webdav.org/groups/authors/ (the ˘authors" group) is http://www.webdav.org/groups/authors/ (the "authors" group) is
granted DAV:write and DAV:read-acl privileges. granted DAV:write and DAV:read-acl privileges.
The following example shows a DAV:acl-principal-props report The following example shows a DAV:acl-principal-prop-set report
requesting the DAV:displayname property. It returns the value of requesting the DAV:displayname property. It returns the value of
DAV:displayname for resources http://www.webdav.org/people/gstein and DAV:displayname for resources http://www.webdav.org/people/gstein
http://www.webdav.org/groups/authors/ , but not for DAV:all, since and http://www.webdav.org/groups/authors/ , but not for DAV:all,
this is not an http(s) URL. since this is not an http(s) URL.
>> Request << >> Request <<
REPORT /index.html HTTP/1.1 REPORT /index.html HTTP/1.1
Host: www.webdav.org Host: www.webdav.org
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:acl-principal-props xmlns:D="DAV:"> <D:acl-principal-prop-set xmlns:D="DAV:">
Clemm, Hopkins, Sedlar, Whitehead [Page 45]
<D:prop> <D:prop>
<D:displayname/> <D:displayname/>
</D:prop> </D:prop>
</D:acl-principal-props> </D:acl-principal-prop-set>
>> Response << >> Response <<
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"> <D:multistatus xmlns:D="DAV:">
<D:response> <D:response>
skipping to change at line 2082 skipping to change at line 2225
<D:prop> <D:prop>
<D:displayname>Greg Stein</D:displayname> <D:displayname>Greg Stein</D:displayname>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
<D:response> <D:response>
<D:href>http://www.webdav.org/groups/authors/</D:href> <D:href>http://www.webdav.org/groups/authors/</D:href>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
Clemm, Hopkins, Sedlar, Whitehead [Page 41]
<D:displayname>Site authors</D:displayname> <D:displayname>Site authors</D:displayname>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
9.3 DAV:principal-match REPORT 9.3 DAV:principal-match REPORT
The DAV:principal-match REPORT is used to identify all members of a The DAV:principal-match REPORT is used to identify all members of a
collection that match the current user. In particular, if the collection that match the current user. In particular, if the
collection contains principals, the report can be used to identify collection contains principals, the report can be used to identify
all members of the collection that match the current user. all members of the collection that match the current user.
Alternatively, if the collection contains resources that have a Alternatively, if the collection contains resources that have a
property that identifies a principal (e.g. DAV:owner), then the property that identifies a principal (e.g. DAV:owner), then the
report can be used to identify all members of the collection whose report can be used to identify all members of the collection whose
property identifies a principal that matches the current user. For property identifies a principal that matches the current user. For
example, this report can return all of the resources in a collection example, this report can return all of the resources in a
hierarchy that are owned by the current user. collection hierarchy that are owned by the current user.
The Depth header (defined in Section 9.2 of [RFC2518]), with value
"infinity", can be used with this report. In this case, the report
operates on the collection in the Request-URI, as well as all child
collections, grandchild collections, etc.
Marshalling: Marshalling:
Clemm, Hopkins, Sedlar, Whitehead [Page 46]
The request body MUST be a DAV:principal-match XML element. The request body MUST be a DAV:principal-match XML element.
<!ELEMENT principal-match ((principal-property | self), prop?)> <!ELEMENT principal-match ((principal-property | self), prop?)>
<!ELEMENT principal-property ANY> <!ELEMENT principal-property ANY>
ANY value: an element whose value identifies a property. The ANY value: an element whose value identifies a property. The
expectation is the value of the named property typically contains expectation is the value of the named property typically
an href element that contains the URI of a principal contains an href element that contains the URI of a principal
<!ELEMENT self EMPTY> <!ELEMENT self EMPTY>
prop: see RFC 2518, Section 12.11 prop: see RFC 2518, Section 12.11
The response body for a successful request MUST be a DAV:multistatus The response body for a successful request MUST be a
XML element. DAV:multistatus XML element.
multistatus: see RFC 2518, Section 12.9 multistatus: see RFC 2518, Section 12.9
The response body for a successful DAV:principal-match REPORT request The response body for a successful DAV:principal-match REPORT
MUST contain a DAV:response element for each member of the collection request MUST contain a DAV:response element for each member of the
that matches the current user. When the DAV:principal-property collection that matches the current user. When the DAV:principal-
element is used, a match occurs if the current user is the same as property element is used, a match occurs if the current user is
the principal identified by the URI found in the DAV:href element of matched by the principal identified by the URI found in the
the property identified by the DAV:principal-property element. When DAV:href element of the property identified by the DAV:principal-
the DAV:self element is used in a DAV:principal-match report issued property element. When the DAV:self element is used in a
against a collection principal, it matches a child of the collection DAV:principal-match report issued against a group, it matches a
member of the group if that child (a principal resource) identifies
Clemm, Hopkins, Sedlar, Whitehead [Page 42] the same principal as the current user.
principal if that child (a principal resource) identifies the same
principal as the current user.
If DAV:prop is specified in the request body, the properties If DAV:prop is specified in the request body, the properties
specified in the DAV:prop element MUST be reported in the specified in the DAV:prop element MUST be reported in the
DAV:response elements. DAV:response elements.
9.3.1 Example: DAV:principal-match REPORT 9.3.1 Example: DAV:principal-match REPORT
The following example identifies the members of the collection The following example identifies the members of the collection
identified by the URL http://www.webdav.org/doc/ that are owned by identified by the URL http://www.webdav.org/doc/ that are owned by
the current user. The current user (˘gclemm") is authenticated using the current user. The current user ("gclemm") is authenticated
Digest authentication. using Digest authentication.
>> Request << >> Request <<
REPORT /doc/ HTTP/1.1 REPORT /doc/ HTTP/1.1
Host: www.webdav.org Host: www.webdav.org
Authorization: Digest username="gclemm", Authorization: Digest username="gclemm",
realm="gclemm@webdav.org", nonce="...", realm="gclemm@webdav.org", nonce="...",
uri="/papers/", response="...", opaque="..." uri="/papers/", response="...", opaque="..."
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxxx Content-Length: xxxx
Depth: infinity Depth: infinity
Clemm, Hopkins, Sedlar, Whitehead [Page 47]
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:principal-match xmlns:D="DAV:"> <D:principal-match xmlns:D="DAV:">
<D:principal-property> <D:principal-property>
<D:owner/> <D:owner/>
</D:principal-property> </D:principal-property>
</D:principal-match> </D:principal-match>
>> Response << >> Response <<
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
skipping to change at line 2186 skipping to change at line 2322
<D:response> <D:response>
<D:href>http://www.webdav.org/doc/foo.html</D:href> <D:href>http://www.webdav.org/doc/foo.html</D:href>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:response> </D:response>
<D:response> <D:response>
<D:href>http://www.webdav.org/doc/img/bar.gif</D:href> <D:href>http://www.webdav.org/doc/img/bar.gif</D:href>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
Clemm, Hopkins, Sedlar, Whitehead [Page 43]
9.4 DAV:principal-property-search REPORT 9.4 DAV:principal-property-search REPORT
The DAV:principal-property-search REPORT performs a substring search The DAV:principal-property-search REPORT performs a substring
on the character data value of specified properties. The server MUST search on the character data value of specified properties. The
perform caseless matching of substrings. Only properties defined on server may perform caseless matching of substrings. Only properties
principal or collection principal resources are searched. For defined on principal resources are searched. For implementation
implementation efficiency, servers do not typically support substring efficiency, servers do not typically support substring searching on
searching on all properties. A client can discover the set of all properties. A client can discover the set of searchable
searchable properties by using the principal-search-property-set properties by using the DAV:principal-search-property-set REPORT,
REPORT, defined in Section 9.5. defined in Section 9.5.
Implementation Note: The value of a WebDAV property is a sequence Implementation Note: The value of a WebDAV property is a
of well-formed XML, and hence can include any character in the sequence of well-formed XML, and hence can include any character
Unicode/ISO-10646 standard, that is, most known characters in in the Unicode/ISO-10646 standard, that is, most known
human languages. Due to the idiosyncrasies of case mapping across characters in human languages. Due to the idiosyncrasies of case
human languages, implementation of caseless matching is non- mapping across human languages, implementation of caseless
trivial. Implementors are strongly encouraged to consult matching is non-trivial. Implementors are strongly encouraged to
[CaseMap], especially Section 2.3 ("Caseless Matching"), for consult [CaseMap], especially Section 2.3 ("Caseless Matching"),
guidance when implementing their caseless matching algorithms. for guidance when implementing their caseless matching
algorithms.
Marshalling: Marshalling:
The DAV:principal-collection-set property of the resource identified Clemm, Hopkins, Sedlar, Whitehead [Page 48]
by the Request-URI specifies the scope of the DAV:principal-property- The scope of the DAV:principal-property-search REPORT is all
search REPORT, as follows: principal resources that are members of a collection identified in
DAV:principal-collection-set. If a group is in the scope of the
- All principal and collection principal resources identified in DAV:principal-property-search REPORT, all members of that group are
DAV:principal-collection-set are searched also in the scope.
- All principal and collection principal resources that are
descendents of a collection principal resource identified in
DAV:principal collection-set are searched.
Servers MUST support the DAV:principal-property-search REPORT on all Servers MUST support the DAV:principal-property-search REPORT on
principal collections identified in the value of a DAV:principal- all principal collections identified in the value of a
collection-set property. DAV:principal-collection-set property.
The request body MUST be a DAV:principal-property-search XML element The request body MUST be a DAV:principal-property-search XML
containing a search specification and an optional list of properties. element containing a search specification and an optional list of
For every principal that matches the search specification, the properties. For every principal that matches the search
response will contain the value of the properties on that principal. specification, the response will contain the value of the
properties on that principal.
<!ELEMENT principal-property-search ((property-search+), prop?) > <!ELEMENT principal-property-search ((property-search+), prop?) >
The DAV:property-search element contains a prop element enumerating The DAV:property-search element contains a prop element enumerating
the properties to be searched and a caseless-substring element, the properties to be searched and a substring element, containing
containing the search string. the search string, and an optional tag indicating whether or not
case-insensitive string matching should be done (the default is
implementation-dependent).
<!ELEMENT property-search (prop, caseless-substring) > <!ELEMENT property-search (prop, substring, caseless?) >
prop: see RFC 2518, Section 12.11 prop: see RFC 2518, Section 12.11
<!ELEMENT caseless-substring #PCDATA > <!ELEMENT substring #PCDATA >
<!ELEMENT caseless EMPTY>
Clemm, Hopkins, Sedlar, Whitehead [Page 44]
Multiple property-search elements or multiple elements within a Multiple property-search elements or multiple elements within a
DAV:prop element will be interpreted with a logical AND. An empty DAV:prop element will be interpreted with a logical AND. An empty
DAV:caseless-substring element will match all properties specified in DAV:substring element will match all properties specified in its
its parent DAV:property-search element. parent DAV:property-search element.
The response body for a successful request MUST be a DAV:multistatus The response body for a successful request MUST be a
XML element. DAV:multistatus XML element.
multistatus: see RFC 2518, Section 12.9 multistatus: see RFC 2518, Section 12.9
The response body for a successful DAV:principal-property-search The response body for a successful DAV:principal-property-search
REPORT request MUST contain a DAV:response element for each REPORT request MUST contain a DAV:response element for each
principal whose property values satisfy the search specification principal whose property values satisfy the search specification
given in DAV:principal-property-search. given in DAV:principal-property-search.
If DAV:prop is specified in the request body, the properties If DAV:prop is specified in the request body, the properties
specified in the DAV:prop element MUST be reported in the specified in the DAV:prop element MUST be reported in the
DAV:response elements. DAV:response elements.
Errors: Clemm, Hopkins, Sedlar, Whitehead [Page 49]
Preconditions:
If a request specifies a search of a property that is not (DAV:non-searchable-property): All properties specified in the
searchable, a 403 (Forbidden) response MUST be returned and the DAV:principal-property-search REPORT must be searchable.
response body MUST be a DAV:non-searchable-property element,
containing the unsearchable properties.
<!ELEMENT non-searchable-property (prop) >
9.4.1 Matching 9.4.1 Matching
There are several cases to consider when matching strings. The There are several cases to consider when matching strings. The
easiest case is when a property value is "simple" and has only easiest case is when a property value is "simple" and has only
character information item content (see [REC-XMLINFOSET]). For character information item content (see [REC-XML-INFOSET]). For
example, the search string "julian" would match the DAV:displayname example, the search string "julian" would match the DAV:displayname
property with value "Julian Reschke". Note that the on-the-wire property with value "Julian Reschke". Note that the on-the-wire
marshalling of DAV:displayname in this case is: marshalling of DAV:displayname in this case is:
<D:displayname xmlns:D="DAV:">Julian Reschke</D:displayname> <D:displayname xmlns:D="DAV:">Julian Reschke</D:displayname>
The name of the property is encoded into the XML element information The name of the property is encoded into the XML element
item, and the character information item content of the property is information item, and the character information item content of the
"Julian Reschke". property is "Julian Reschke".
The more complicated case occurred when properties have mixed content The more complicated case occurred when properties have mixed
(that is, compound values consisting of multiple child element items, content (that is, compound values consisting of multiple child
other types of information items, and character information item element items, other types of information items, and character
content). Consider the property http://www.webdav.org/props/aprop, information item content). Consider the property
marshalled as: http://www.webdav.org/props/aprop, marshalled as:
Clemm, Hopkins, Sedlar, Whitehead [Page 45]
<W:aprop xmlns:W="http://www.webdav.org/props/"> <W:aprop xmlns:W="http://www.webdav.org/props/">
{cdata 0}<W:elem1>{cdata 1}</W:elem1> {cdata 0}<W:elem1>{cdata 1}</W:elem1>
<W:elem2>{cdata 2}</W:elem2>{cdata 3} <W:elem2>{cdata 2}</W:elem2>{cdata 3}
</W:aprop> </W:aprop>
In this case, substring matching is performed on each individual In this case, substring matching is performed on each individual
contiguous sequence of character information items. In the example contiguous sequence of character information items. In the example
above, a search string would be compared to the four following above, a search string would be compared to the four following
strings: strings:
{cdata 0} {cdata 0}
{cdata 1} {cdata 1}
{cdata 2} {cdata 2}
{cdata 3} {cdata 3}
That is, four individual caseless substring matches would be That is, four individual substring matches would be performed, one
performed, one each for {cdata 0}, {cdata 1}, {cdata 2}, and {cdata each for {cdata 0}, {cdata 1}, {cdata 2}, and {cdata 3}.
3}.
Clemm, Hopkins, Sedlar, Whitehead [Page 50]
9.4.2 Example: successful DAV:principal-property-search REPORT 9.4.2 Example: successful DAV:principal-property-search REPORT
In this example, the client requests the principal URLs of all users In this example, the client requests the principal URLs of all
whose DAV:displayname property contains the substring "doE" and whose users whose DAV:displayname property contains the substring "doE"
http://BigCorp.com/ns/title property (that is, their professional and whose http://BigCorp.com/ns/title property (that is, their
title) contains "sales". In addition, the client requests five professional title) contains "Sales". In addition, the client
properties to be returned with the matching principals: requests five properties to be returned with the matching
principals:
In the DAV: namespace: displayname In the DAV: namespace: displayname
In the http://www.BigCorp.com/ns/ namespace: department, phone, In the http://www.BigCorp.com/ns/ namespace: department, phone,
office, salary office, salary
The response shows that two principal resources meet the search The response shows that two principal resources meet the search
specification, "John Doe" and "Zygdoebert Smith". The property specification, "John Doe" and "Zygdoebert Smith". The property
"salary" in namespace "http://www.BigCorp.com/ns/" is not returned, "salary" in namespace "http://www.BigCorp.com/ns/" is not returned,
since the principal making the request does not have sufficient since the principal making the request does not have sufficient
access permissions to read this property. access permissions to read this property.
skipping to change at line 2339 skipping to change at line 2470
REPORT /users/ HTTP/1.1 REPORT /users/ HTTP/1.1
Host: www.BigCorp.com Host: www.BigCorp.com
Content-Type: text/xml; charset=utf-8 Content-Type: text/xml; charset=utf-8
Content-Length: xxxx Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:principal-property-search xmlns:D="DAV:"> <D:principal-property-search xmlns:D="DAV:">
<D:property-search> <D:property-search>
<D:prop> <D:prop>
Clemm, Hopkins, Sedlar, Whitehead [Page 46]
<D:displayname/> <D:displayname/>
</D:prop> </D:prop>
<D:caseless-substring>doE</D:caseless-substring> <D:substring>doE</D:substring>
<D:caseless/>
</D:property-search> </D:property-search>
<D:property-search> <D:property-search>
<D:prop xmlns:B="http://www.BigCorp.com/ns/"> <D:prop xmlns:B="http://www.BigCorp.com/ns/">
<B:title/> <B:title/>
</D:prop> </D:prop>
<D:caseless-substring>sales</D:caseless-substring> <D:substring>Sales</D: substring>
</D:property-search> </D:property-search>
<D:prop xmlns:B="http://www.BigCorp.com/ns/"> <D:prop xmlns:B="http://www.BigCorp.com/ns/">
<D:displayname/> <D:displayname/>
<B:department/> <B:department/>
<B:phone/> <B:phone/>
<B:office/> <B:office/>
Clemm, Hopkins, Sedlar, Whitehead [Page 51]
<B:salary/> <B:salary/>
</D:prop> </D:prop>
</D:principal-property-search> </D:principal-property-search>
>> Response << >> Response <<
HTTP/1.1 207 Multi-Status HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset=utf-8 Content-Type: text/xml; charset=utf-8
Content-Length: xxxx Content-Length: xxxx
skipping to change at line 2389 skipping to change at line 2521
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<B:salary/> <B:salary/>
</D:prop> </D:prop>
<D:status>HTTP/1.1 403 Forbidden</D:status> <D:status>HTTP/1.1 403 Forbidden</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
<D:response> <D:response>
<D:href>http://www.BigCorp.com/users/zsmith</D:href> <D:href>http://www.BigCorp.com/users/zsmith</D:href>
<D:propstat> <D:propstat>
Clemm, Hopkins, Sedlar, Whitehead [Page 47]
<D:prop> <D:prop>
<D:displayname>Zygdoebert Smith</D:displayname> <D:displayname>Zygdoebert Smith</D:displayname>
<B:department>Gadget Sales</B:department> <B:department>Gadget Sales</B:department>
<B:phone>234-7654</B:phone> <B:phone>234-7654</B:phone>
<B:office>114</B:office> <B:office>114</B:office>
</D:prop> </D:prop>
<D:status>HTTP/1.1 200 OK</D:status> <D:status>HTTP/1.1 200 OK</D:status>
</D:propstat> </D:propstat>
<D:propstat> <D:propstat>
<D:prop> <D:prop>
<B:salary/> <B:salary/>
</D:prop> </D:prop>
Clemm, Hopkins, Sedlar, Whitehead [Page 52]
<D:status>HTTP/1.1 403 Forbidden</D:status> <D:status>HTTP/1.1 403 Forbidden</D:status>
</D:propstat> </D:propstat>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
9.4.3 Example: Unsuccessful DAV:principal-property-search REPORT 9.4.3 Example: Unsuccessful DAV:principal-property-search REPORT
In this example, the client requests a search on the non-searchable In this example, the client requests a search on the non-searchable
property "phone" in the namespace "http://www.BigCorp.com/ns/". The property "phone" in the namespace "http://www.BigCorp.com/ns/".
response is a 403 (Forbidden), with a response body containing the The response is a 403 (Forbidden), with a response body containing
XML element DAV:non-searchable-property listing the non-searchable a DAV:non-searchable-property XML element as the value of a
property. DAV:error XML element.
>> Request << >> Request <<
REPORT /users/ HTTP/1.1 REPORT /users/ HTTP/1.1
Host: www.BigCorp.com Host: www.BigCorp.com
Content-Type: text/xml; charset=utf-8 Content-Type: text/xml; charset=utf-8
Content-Length: xxxx Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:principal-property-search xmlns:D="DAV:"> <D:principal-property-search xmlns:D="DAV:">
skipping to change at line 2439 skipping to change at line 2571
<D:caseless-substring>232</D:caseless-substring> <D:caseless-substring>232</D:caseless-substring>
</D:property-search> </D:property-search>
</D:principal-property-search> </D:principal-property-search>
>> Response << >> Response <<
HTTP/1.1 403 FORBIDDEN HTTP/1.1 403 FORBIDDEN
Content-Type: text/xml; charset=utf-8 Content-Type: text/xml; charset=utf-8
Content-Length: xxxx Content-Length: xxxx
Clemm, Hopkins, Sedlar, Whitehead [Page 48]
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:non-searchable-property xmlns:D="DAV:"> <D:error xmlns:D="DAV:">
<D:non-searchable-property>
<D:prop xmlns:B="http://www.BigCorp.com/ns/"> <D:prop xmlns:B="http://www.BigCorp.com/ns/">
<B:phone/> <B:phone/>
</D:prop> </D:prop>
</D:non-searchable-property> </D:non-searchable-property>
</D:error>
Clemm, Hopkins, Sedlar, Whitehead [Page 53]
9.5 DAV:principal-search-property-set REPORT 9.5 DAV:principal-search-property-set REPORT
The DAV:principal-search-property-set REPORT identifies those The DAV:principal-search-property-set REPORT identifies those
properties that may be searched using the DAV:principal-property- properties that may be searched using the DAV:principal-property-
search REPORT (defined in Section 9.4). The DAV:principal-collection- search REPORT (defined in Section 9.4).
set property of the resource identified by the Request-URI specifies
the scope of the DAV:principal-search-property-set REPORT, as
follows:
- All principal and collection principal resources identified in
DAV:principal-collection-set are in scope
- All principal and collection principal resources that are
descendents of a collection principal resource identified in
DAV:principal collection-set are also in scope.
Principals and collection principals within this scope are examined
for searchable properties.
Servers MUST support the DAV:principal-search-property-set REPORT on Servers MUST support the DAV:principal-search-property-set REPORT
all principal collections identified in the value of a DAV:principal- on all principal collections identified in the value of a
collection-set property. DAV:principal-collection-set property.
An access control protocol user agent could use the results of the An access control protocol user agent could use the results of the
DAV:principal-search-property-set REPORT to present a query interface DAV:principal-search-property-set REPORT to present a query
to the user for retrieving principals. interface to the user for retrieving principals.
Marshalling: Marshalling:
The request body MUST be an empty DAV:principal-search-property-set The request body MUST be an empty DAV:principal-search-property-set
XML element. XML element.
The response body MUST be a DAV:principal-search-property-set XML The response body MUST be a DAV:principal-search-property-set XML
element, containing a DAV:principal-search-property XML element for element, containing a DAV:principal-search-property XML element for
each property that may be searched with the DAV:principal-property- each property that may be searched with the DAV:principal-property-
search REPORT. A server MAY limit its response to just a subset of search REPORT. A server MAY limit its response to just a subset of
the searchable properties, such as those likely to be useful to an the searchable properties, such as those likely to be useful to an
interactive access control client. interactive access control client.
<!ELEMENT principal-search-property-set (principal-search- <!ELEMENT principal-search-property-set (principal-search-
property*) > property*) >
Each DAV:principal-search-property XML element contains exactly one Each DAV:principal-search-property XML element contains exactly one
searchable property, and a description of the property. searchable property, and a description of the property.
Clemm, Hopkins, Sedlar, Whitehead [Page 49]
<!ELEMENT principal-search-property (prop, description) > <!ELEMENT principal-search-property (prop, description) >
The DAV:prop element contains one principal property on which the The DAV:prop element contains one principal property on which the
server is able to perform DAV:principal-property-search REPORTs. server is able to perform a DAV:principal-property-search REPORT.
prop: see RFC 2518, Section 12.11 prop: see RFC 2518, Section 12.11
The description element is a human-readable description of what The description element is a human-readable description of what
information this property represents. Servers MUST indicate the human information this property represents. Servers MUST indicate the
language of the description using the xml:lang attribute and SHOULD human language of the description using the xml:lang attribute and
consider the HTTP Accept-Language request header when selecting one SHOULD consider the HTTP Accept-Language request header when
of multiple available languages. selecting one of multiple available languages.
<!ELEMENT description #PCDATA > <!ELEMENT description #PCDATA >
Clemm, Hopkins, Sedlar, Whitehead [Page 54]
9.5.1 Example: DAV:principal-search-property-set REPORT 9.5.1 Example: DAV:principal-search-property-set REPORT
In this example, the client determines the set of searchable In this example, the client determines the set of searchable
principal properties by requesting the DAV:principal-search-property- principal properties by requesting the DAV:principal-search-
set REPORT on the root of the serverĂs principal URL collection set, property-set REPORT on the root of the server's principal URL
identified by http://www.BigCorp.com/users/. collection set, identified by http://www.BigCorp.com/users/.
>> Request << >> Request <<
REPORT /users/ HTTP/1.1 REPORT /users/ HTTP/1.1
Host: www.BigCorp.com Host: www.BigCorp.com
Content-Type: text/xml; charset="utf-8" Content-Type: text/xml; charset="utf-8"
Content-Length: xxx Content-Length: xxx
Accept-Language: en, de Accept-Language: en, de
Authorization: BASIC d2FubmFtYWs6cGFzc3dvcmQ= Authorization: BASIC d2FubmFtYWs6cGFzc3dvcmQ=
skipping to change at line 2543 skipping to change at line 2665
<D:principal-search-property-set xmlns:D="DAV:"> <D:principal-search-property-set xmlns:D="DAV:">
<D:principal-search-property> <D:principal-search-property>
<D:prop> <D:prop>
<D:displayname/> <D:displayname/>
</D:prop> </D:prop>
<D:description xml:lang="en">Full name</D:description> <D:description xml:lang="en">Full name</D:description>
</D:principal-search-property> </D:principal-search-property>
<D:principal-search-property> <D:principal-search-property>
<D:prop xmlns:B="http://BigCorp.com/ns/"> <D:prop xmlns:B="http://BigCorp.com/ns/">
<B:title/> <B:title/>
Clemm, Hopkins, Sedlar, Whitehead [Page 50]
</D:prop> </D:prop>
<D:description xml:lang="en">Job title</D:description> <D:description xml:lang="en">Job title</D:description>
</D:principal-search-property> </D:principal-search-property>
</D:principal-search-property-set> </D:principal-search-property-set>
Clemm, Hopkins, Sedlar, Whitehead [Page 55]
10 XML PROCESSING 10 XML PROCESSING
Implementations of this specification MUST support the XML element Implementations of this specification MUST support the XML element
ignore rule, as specified in Section 23.3.2 of [RFC2518], and the XML ignore rule, as specified in Section 23.3.2 of [RFC2518], and the
Namespace Recommendation [REC-XML-NAMES]. XML Namespacerecommendation [REC-XML-NAMES].
Note that use of the DAV namespace is reserved for XML elements and Note that use of the DAV namespace is reserved for XML elements and
property names defined in a standards-track or Experimental IETF RFC. property names defined in a standards-track or Experimental IETF
RFC.
11 INTERNATIONALIZATION CONSIDERATIONS 11 INTERNATIONALIZATION CONSIDERATIONS
In this specification, the only human-readable content can be found In this specification, the only human-readable content can be found
in the description XML element, found within the DAV:supported- in the description XML element, found within the DAV:supported-
privilege-set property. This element contains a human-readable privilege-set property. This element contains a human-readable
description of the capabilities controlled by a privilege. As a description of the capabilities controlled by a privilege. As a
result, the description element must be capable of representing result, the description element must be capable of representing
descriptions in multiple character sets. Since the description descriptions in multiple character sets. Since the description
element is found within a WebDAV property, it is represented on-the- element is found within a WebDAV property, it is represented on-
wire as XML [REC-XML], and hence can leverage XML's language tagging the-wire as XML [REC-XML], and hence can leverage XML's language
and character set encoding capabilities. Specifically, XML processors tagging and character set encoding capabilities. Specifically, XML
must, at minimum, be able to read XML elements encoded using the UTF- processors must, at minimum, be able to read XML elements encoded
8 [UTF-8] encoding of the ISO 10646 multilingual plane. XML examples using the UTF-8 [UTF-8] encoding of the ISO 10646 multilingual
in this specification demonstrate use of the charset parameter of the plane. XML examples in this specification demonstrate use of the
Content-Type header, as defined in [RFC3023], as well as the XML charset parameter of the Content-Type header, as defined in
"encoding" attribute, which together provide charset identification [RFC3023], as well as the XML "encoding" attribute, which together
information for MIME and XML processors. Furthermore, this provide charset identification information for MIME and XML
specification requires server implementations to tag description processors. Futhermore, this specification requires server
fields with the xml:lang attribute (see Section 2.12 of [REC-XML]), implementations to tag description fields with the xml:lang
which specifies the human language of the description. Additionally, attribute (see Section 2.12 of [REC-XML]), which specifies the
server implementations should take into account the value of the human language of the description. Additionally, server
Accept-Language HTTP header to determine which description string to implementations should take into account the value of the Accept-
Language HTTP header to determine which description string to
return. return.
For XML elements other than the description element, it is expected For XML elements other than the description element, it is expected
that implementations will treat the property names, privilege names, that implementations will treat the property names, privilege
and values as tokens, and convert these tokens into human-readable names, and values as tokens, and convert these tokens into human-
text in the user's language and character set when displayed to a readable text in the user's language and character set when
person. Only a generic WebDAV property display utility would display displayed to a person. Only a generic WebDAV property display
these values in their raw form to a human user. utility would display these values in their raw form to a human
user.
For error reporting, we follow the convention of HTTP/1.1 status For error reporting, we follow the convention of HTTP/1.1 status
codes, including with each status code a short, English description codes, including with each status code a short, English description
of the code (e.g., 200 (OK)). While the possibility exists that a of the code (e.g., 200 (OK)). While the possibility exists that a
poorly crafted user agent would display this message to a user,
Clemm, Hopkins, Sedlar, Whitehead [Page 51] Clemm, Hopkins, Sedlar, Whitehead [Page 56]
internationalized applications will ignore this message, and display poorly crafted user agent would display this message to a user,
an appropriate message in the user's language and character set. internationalized applications will ignore this message, and
display an appropriate message in the user's language and character
set.
Further internationalization considerations for this protocol are Further internationalization considerations for this protocol are
described in the WebDAV Distributed Authoring protocol specification described in the WebDAV Distributed Authoring protocol
[RFC2518]. specification [RFC2518].
12 SECURITY CONSIDERATIONS 12 SECURITY CONSIDERATIONS
Applications and users of this access control protocol should be Applications and users of this access control protocol should be
aware of several security considerations, detailed below. In addition aware of several security considerations, detailed below. In
to the discussion in this document, the security considerations addition to the discussion in this document, the security
detailed in the HTTP/1.1 specification [RFC2616], the WebDAV considerations detailed in the HTTP/1.1 specification [RFC2616],
Distributed Authoring Protocol specification [RFC2518], and the XML the WebDAV Distributed Authoring Protocol specification [RFC2518],
Media Types specification [RFC3023] should be considered in a and the XML Media Types specification [RFC3023] should be
security analysis of this protocol. considered in a security analysis of this protocol.
12.1 Increased Risk of Compromised Users 12.1 Increased Risk of Compromised Users
In the absence of a mechanism for remotely manipulating access In the absence of a mechanism for remotely manipulating access
control lists, if a single user's authentication credentials are control lists, if a single user's authentication credentials are
compromised, only those resources for which the user has access compromised, only those resources for which the user has access
permission can be read, modified, moved, or deleted. With the permission can be read, modified, moved, or deleted. With the
introduction of this access control protocol, if a single compromised introduction of this access control protocol, if a single
user has the ability to change ACLs for a broad range of other users compromised user has the ability to change ACLs for a broad range
(e.g., a super-user), the number of resources that could be altered of other users (e.g., a super-user), the number of resources that
by a single compromised user increases. This risk can be mitigated by could be altered by a single compromised user increases. This risk
limiting the number of people who have write-acl privileges across a can be mitigated by limiting the number of people who have write-
broad range of resources. acl privileges across a broad range of resources.
12.2 Risks of the DAV:read-acl and DAV:current-user-privilege-set 12.2 Risks of the DAV:read-acl and DAV:current-user-privilege-set
Privileges Privileges
The ability to read the access privileges (stored in the DAV:acl The ability to read the access privileges (stored in the DAV:acl
property), or the privileges permitted the currently authenticated property), or the privileges permitted the currently authenticated
user (stored in the DAV:current-user-privilege-set property) on a user (stored in the DAV:current-user-privilege-set property) on a
resource may seem innocuous, since reading an ACL cannot possibly resource may seem innocuous, since reading an ACL cannot possibly
affect the resource's state. However, if all resources have world- affect the resource's state. However, if all resources have world-
readable ACLs, it is possible to perform an exhaustive search for readable ACLs, it is possible to perform an exhaustive search for
those resources that have inadvertently left themselves in a those resources that have inadvertently left themselves in a
vulnerable state, such as being world-writeable. In particular, the vulnerable state, such as being world-writeable. In particular, the
property retrieval method PROPFIND, executed with Depth infinity on property retrieval method PROPFIND, executed with Depth infinity on
an entire hierarchy, is a very efficient way to retrieve the DAV:acl an entire hierarchy, is a very efficient way to retrieve the
or DAV:current-user-privilege-set properties. Once found, this DAV:acl or DAV:current-user-privilege-set properties. Once found,
vulnerability can be exploited by a denial of service attack in which this vulnerability can be exploited by a denial of service attack
the open resource is repeatedly overwritten. Alternately, writeable
resources can be modified in undesirable ways. Clemm, Hopkins, Sedlar, Whitehead [Page 57]
in which the open resource is repeatedly overwritten. Alternately,
writeable resources can be modified in undesirable ways.
To reduce this risk, read-acl privileges should not be granted to To reduce this risk, read-acl privileges should not be granted to
unauthenticated principals, and restrictions on read-acl and read- unauthenticated principals, and restrictions on read-acl and read-
Clemm, Hopkins, Sedlar, Whitehead [Page 52]
current-user-privilege-set privileges for authenticated principals current-user-privilege-set privileges for authenticated principals
should be carefully analyzed when deploying this protocol. Access to should be carefully analyzed when deploying this protocol. Access
the current-user-privilege-set property will involve a tradeoff of to the current-user-privilege-set property will involve a tradeoff
usability versus security. When the current-user-privilege-set is of usability versus security. When the current-user-privilege-set
visible, user interfaces are expected to provide enhanced information is visible, user interfaces are expected to provide enhanced
concerning permitted and restricted operations, yet this information information concerning permitted and restricted operations, yet
may also indicate a vulnerability that could be exploited. Deployment this information may also indicate a vulnerability that could be
of this protocol will need to evaluate this tradeoff in light of the exploited. Deployment of this protocol will need to evaluate this
requirements of the deployment environment. tradeoff in light of the requirements of the deployment
environment.
12.3 No Foreknowledge of Initial ACL 12.3 No Foreknowledge of Initial ACL
In an effort to reduce protocol complexity, this protocol In an effort to reduce protocol complexity, this protocol
specification intentionally does not address the issue of how to specification intentionally does not address the issue of how to
manage or discover the initial ACL that is placed upon a resource manage or discover the initial ACL that is placed upon a resource
when it is created. The only way to discover the initial ACL is to when it is created. The only way to discover the initial ACL is to
create a new resource, then retrieve the value of the DAV:acl create a new resource, then retrieve the value of the DAV:acl
property. This assumes the principal creating the resource also has property. This assumes the principal creating the resource also has
been granted the DAV:read-acl privilege. been granted the DAV:read-acl privilege.
As a result, it is possible that a principal could create a resource, As a result, it is possible that a principal could create a
and then discover that its ACL grants privileges that are resource, and then discover that its ACL grants privileges that are
undesirable. Furthermore, this protocol makes it possible (though undesirable. Furthermore, this protocol makes it possible (though
unlikely) that the creating principal could be unable to modify the unlikely) that the creating principal could be unable to modify the
ACL, or even delete the resource. Even when the ACL can be modified, ACL, or even delete the resource. Even when the ACL can be
there will be a short period of time when the resource exists with modified, there will be a short period of time when the resource
the initial ACL before its new ACL can be set. exists with the initial ACL before its new ACL can be set.
Several factors mitigate this risk. Human principals are often aware Several factors mitigate this risk. Human principals are often
of the default access permissions in their editing environments and aware of the default access permissions in their editing
take this into account when writing information. Furthermore, default environments and take this into account when writing information.
privilege policies are usually very conservative, limiting the Furthermore, default privilege policies are usually very
privileges granted by the initial ACL. conservative, limiting the privileges granted by the initial ACL.
13 AUTHENTICATION 13 AUTHENTICATION
Authentication mechanisms defined for use with HTTP and WebDAV also Authentication mechanisms defined for use with HTTP and WebDAV
apply to this WebDAV Access Control Protocol, in particular the Basic also apply to this WebDAV Access Control Protocol, in particular
and Digest authentication mechanisms defined in [RFC2617]. the Basic and Digest authentication mechanisms defined in
[RFC2617].
Clemm, Hopkins, Sedlar, Whitehead [Page 58]
14 IANA CONSIDERATIONS 14 IANA CONSIDERATIONS
This document uses the namespace defined by [RFC2518] for XML This document uses the namespace defined by [RFC2518] for XML
elements. All other IANA considerations mentioned in [RFC2518] also elements. All other IANA considerations mentioned in [RFC2518]
applicable to WebDAV ACL. also applicable to WebDAV ACL.
Clemm, Hopkins, Sedlar, Whitehead [Page 53]
15 INTELLECTUAL PROPERTY 15 INTELLECTUAL PROPERTY
The following notice is copied from RFC 2026, section 10.4, and The following notice is copied from RFC 2026, section 10.4, and
describes the position of the IETF concerning intellectual property describes the position of the IETF concerning intellectual property
claims made against this document. claims made against this document.
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to intellectual property or other rights that might be claimed to
pertain to the implementation or use other technology described in pertain to the implementation or use other technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the has made any effort to identify any such rights. Information on
IETF's procedures with respect to rights in standards-track and the IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of claims of rights made available for publication and any assurances
licenses to be made available, or the result of an attempt made to of licenses to be made available, or the result of an attempt made
obtain a general license or permission for the use of such to obtain a general license or permission for the use of such
proprietary rights by implementers or users of this specification can proprietary rights by implementers or users of this specification
be obtained from the IETF Secretariat. can be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to practice rights that may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive this standard. Please address the information to the IETF
Director. Executive Director.
16 ACKNOWLEDGEMENTS 16 ACKNOWLEDGEMENTS
This protocol is the collaborative product of the WebDAV ACL design This protocol is the collaborative product of the WebDAV ACL design
team: Bernard Chester, Geoff Clemm, Anne Hopkins, Barry Lind, Sean team: Bernard Chester, Geoff Clemm, Anne Hopkins, Barry Lind, Sean
Lyndersay, Eric Sedlar, Greg Stein, and Jim Whitehead. The authors Lyndersay, Eric Sedlar, Greg Stein, and Jim Whitehead. The authors
are grateful for the detailed review and comments provided by Jim are grateful for the detailed review and comments provided by Jim
Amsden, Gino Basso, Murthy Chintalapati, Dennis Hamilton, Laurie Amsden, Gino Basso, Murthy Chintalapati, Dennis Hamilton, Laurie
Harper, Ron Jacobs, Chris Knight, Remy Maucherat, Larry Masinter, Harper, Ron Jacobs, Chris Knight, Remy Maucherat, Larry Masinter,
Yaron Goland, Lisa Dusseault, Joe Orton, Stefan Eissing, Julian Yaron Goland, Lisa Dusseault, Joe Orton, Stefan Eissing, Julian
Reschke, Keith Wannamaker, Tim Ellison, and Dylan Barrell. We thank Reschke, Keith Wannamaker, Tim Ellison, Peter Raymond, and Dylan
Keith Wannamaker for the initial text of the principal property Barrell. We thank Keith Wannamaker for the initial text of the
search sections. Prior work on WebDAV access control protocols has principal property search sections. Prior work on WebDAV access
been performed by Yaron Goland, Paul Leach, Lisa Dusseault, Howard control protocols has been performed by Yaron Goland, Paul Leach,
Palmer, and Jon Radoff. We would like to acknowledge the foundation Lisa Dusseault, Howard Palmer, and Jon Radoff. We would like to
laid for us by the authors of the DeltaV, WebDAV and HTTP protocols acknowledge the foundation laid for us by the authors of the
upon which this protocol is layered, and the invaluable feedback from
the WebDAV working group.
Clemm, Hopkins, Sedlar, Whitehead [Page 54] Clemm, Hopkins, Sedlar, Whitehead [Page 59]
DeltaV, WebDAV and HTTP protocols upon which this protocol is
layered, and the invaluable feedback from the WebDAV working group.
17 REFERENCES 17 REFERENCES
17.1 Normative References 17.1 Normative References
[RFC2119] S.Bradner, "Key words for use in RFCs to Indicate [RFC2119] S.Bradner, "Key words for use in RFCs to Indicate
Requirement Levels." RFC 2119, BCP 14, Harvard, March, 1997. Requirement Levels." RFC 2119, BCP 14, March, 1997.
[REC-XML] T. Bray, J. Paoli, C.M. Sperberg-McQueen, "Extensible [REC-XML] T. Bray, J. Paoli, C.M. Sperberg-McQueen, "Extensible
Markup Language (XML)." World Wide Web Consortium Recommendation REC- Markup Language (XML)." World Wide Web Consortium Recommendation
xml.http://www.w3.org/TR/REC-xml REC-xml.http://www.w3.org/TR/REC-xml
[REC-XML-NAMES] T. Bray, D. Hollander, A. Layman, ˘Name Spaces in [REC-XML-NAMES] T. Bray, D. Hollander, A. Layman, "Name Spaces in
XML" World Wide Web Consortium Recommendation REC-xml-names. XML" World Wide Web Consortium Recommendation REC-xml-names.
http://www.w3.org/TR/REC-xml-names/ http://www.w3.org/TR/REC-xml-names/
[RFCxxxx] G. Clemm, J. Amsden, T. Ellison, C. Kaler, J. Whitehead, [RFC3253] G. Clemm, J. Amsden, T. Ellison, C. Kaler, J. Whitehead,
"Versioning Extensions to WebDAV." RFC xxxx. Rational, IBM, "Versioning Extensions to WebDAV." RFC 3253, March 2002.
Microsoft, U.C. Santa Cruz, 2001.
[REC-XML-INFOSET] J. Cowan, R. Tobin, "XML Information Set." World [REC-XML-INFOSET] J. Cowan, R. Tobin, "XML Information Set." World
Wide Web Consortium Recommendation REC-xml-infoset. Wide Web Consortium Recommendation REC-xml-infoset.
http://www.w3.org/TR/xml-infoset/ http://www.w3.org/TR/xml-infoset/
[RFC2616] R. Fielding, J. Gettys, J. C. Mogul, H. Frystyk, L. [RFC2616] R. Fielding, J. Gettys, J. C. Mogul, H. Frystyk, L.
Masinter, P. Leach, and T. Berners-Lee, "Hypertext Transfer Protocol Masinter, P. Leach, and T. Berners-Lee, "Hypertext Transfer
-- HTTP/1.1." RFC 2616. U.C. Irvine, Compaq, Xerox, Microsoft, Protocol -- HTTP/1.1." RFC 2616, June, 1999.
MIT/LCS, June, 1999.
[RFC2617] J. Franks, P. Hallam-Baker, J. Hostetler, S. Lawrence, P. [RFC2617] J. Franks, P. Hallam-Baker, J. Hostetler, S. Lawrence, P.
Leach, A. Luotonen, L. Stewart, "HTTP Authentication: Basic and Leach, A. Luotonen, L. Stewart, "HTTP Authentication: Basic and
Digest Access Authentication." RFC 2617. Northwestern University, Digest Access Authentication." RFC 2617, June, 1999.
Verisign, AbiSource, Agranat, Microsoft, Netscape, Open Market, June,
1999.
[RFC2518] Y. Goland, E. Whitehead, A. Faizi, S. R. Carter, D. Jensen, [RFC2518] Y. Goland, E. Whitehead, A. Faizi, S. R. Carter, D.
"HTTP Extensions for Distributed Authoring -- WEBDAV." RFC 2518. Jensen, "HTTP Extensions for Distributed Authoring -- WEBDAV." RFC
Microsoft, U.C. Irvine, Netscape, Novell, February, 1999. 2518, February, 1999.
[RFC2368] P. Hoffman, L. Masinter, J. Zawinski, "The mailto URL [RFC2368] P. Hoffman, L. Masinter, J. Zawinski, "The mailto URL
scheme." RFC 2368. Internet Mail Consortium, Xerox, Netscape, July, scheme." RFC 2368, July, 1998.
1998.
[RFC3023] M. Murata, S. St.Laurent, D. Kohn, "XML Media Types." RFC [RFC3023] M. Murata, S. St.Laurent, D. Kohn, "XML Media Types." RFC
3023. IBM Tokyo Research Laboratory, simonstl.com, Skymoon Ventures, 3023, January, 2001.
January, 2001.
[UTF-8] F. Yergeau, "UTF-8, a transformation format of Unicode and [UTF-8] F. Yergeau, "UTF-8, a transformation format of Unicode and
ISO 10646." RFC 2279. Alis Technologies. January, 1998. ISO 10646." RFC 2279, January, 1998.
Clemm, Hopkins, Sedlar, Whitehead [Page 55]
Clemm, Hopkins, Sedlar, Whitehead [Page 60]
17.2 Informational References 17.2 Informational References
[RFC2026] S.Bradner, "The Internet Standards Process ű Revision 3." [RFC2026] S.Bradner, "The Internet Standards Process - Revision 3."
RFC 2026, BCP 9. Harvard, October, 1996. RFC 2026, BCP 9. Harvard, October, 1996.
[RFC2255] T. Howes, M. Smith, "The LDAP URL Format." RFC 2255. [RFC2255] T. Howes, M. Smith, "The LDAP URL Format." RFC 2255.
Netscape, December, 1997. Netscape, December, 1997.
[RFC2251] M. Wahl, T. Howes, S. Kille, "Lightweight Directory Access [RFC2251] M. Wahl, T. Howes, S. Kille, "Lightweight Directory
Protocol (v3)." RFC 2251. Critical Angle, Netscape, Isode, December, Access Protocol (v3)." RFC 2251. Critical Angle, Netscape, Isode,
1997. December, 1997.
[CaseMap] M. Davis, "Case Mappings", Unicode Technical Report #21, [CaseMap] M. Davis, "Case Mappings", Unicode Standard Annex #21,
<http://www.unicode.org/unicode/reports/tr21> March 26, 2001. http://www.unicode.org/unicode/reports/tr21
18 AUTHORS' ADDRESSES 18 AUTHORS' ADDRESSES
Geoffrey Clemm Geoffrey Clemm
Rational Software Rational Software
20 Maguire Road 20 Maguire Road
Lexington, MA 02421 Lexington, MA 02421
Email: geoffrey.clemm@rational.com Email: geoffrey.clemm@rational.com
Anne Hopkins Anne Hopkins
skipping to change at line 2836 skipping to change at line 2955
Email: esedlar@us.oracle.com Email: esedlar@us.oracle.com
Jim Whitehead Jim Whitehead
U.C. Santa Cruz U.C. Santa Cruz
Dept. of Computer Science Dept. of Computer Science
Baskin Engineering Baskin Engineering
1156 High Street 1156 High Street
Santa Cruz, CA 95064 Santa Cruz, CA 95064
Email: ejw@cse.ucsc.edu Email: ejw@cse.ucsc.edu
Clemm, Hopkins, Sedlar, Whitehead [Page 56] Clemm, Hopkins, Sedlar, Whitehead [Page 61]
19 APPENDICES
19 APPENDICIES
19.1 WebDAV XML Document Type Definition Addendum 19.1 WebDAV XML Document Type Definition Addendum
All XML elements defined in this Document Type Definition (DTD) All XML elements defined in this Document Type Definition (DTD)
belong to the DAV namespace. This DTD should be viewed as an addendum belong to the DAV namespace. This DTD should be viewed as an
to the DTD provided in [RFC2518], section 23.1. addendum to the DTD provided in [RFC2518], section 23.1.
<!-- Privileges --> <!-- Privileges -->
<!ELEMENT read EMPTY> <!ELEMENT read EMPTY>
<!ELEMENT write EMPTY> <!ELEMENT write EMPTY>
<!ELEMENT write-properties EMPTY>
<!ELEMENT write-content EMPTY>
<!ELEMENT unlock EMPTY>
<!ELEMENT read-acl EMPTY> <!ELEMENT read-acl EMPTY>
<!ELEMENT read-current-user-privilege-set EMPTY> <!ELEMENT read-current-user-privilege-set EMPTY>
<!ELEMENT write-acl EMPTY> <!ELEMENT write-acl EMPTY>
<!ELEMENT all EMPTY> <!ELEMENT all EMPTY>
<!-- Principal Properties (Section 4) --> <!-- Principal Properties (Section 4) -->
<!ELEMENT principalEMPTY> <!ELEMENT principalEMPTY>
<!ELEMENT alternate-URI-set (href*)> <!ELEMENT alternate-URI-set (href*)>
<!ELEMENT principal-URL (href)> <!ELEMENT principal-URL (href)>
<!ELEMENT group-membership (href*)>
<!-- Access Control Properties (Section 5) --> <!-- Access Control Properties (Section 5) -->
<!-- DAV:owner Property (Section 5.1) --> <!-- DAV:owner Property (Section 5.1) -->
<!ELEMENT owner (href prop?)> <!ELEMENT owner (href prop?)>
<!ELEMENT prop (see [RFC2518], section 12.11)> <!ELEMENT prop (see [RFC2518], section 12.11)>
<!-- DAV:supported-privilege-set Property (Section 5.2) --> <!-- DAV:supported-privilege-set Property (Section 5.2) -->
<!ELEMENT supported-privilege-set (supported-privilege*)> <!ELEMENT supported-privilege-set (supported-privilege*)>
<!ELEMENT supported-privilege <!ELEMENT supported-privilege
(privilege, abstract?, description, supported-privilege*)> (privilege, abstract?, description, supported-privilege*)>
<!ELEMENT privilege ANY> <!ELEMENT privilege ANY>
<!ELEMENT abstract EMPTY> <!ELEMENT abstract EMPTY>
<!ELEMENT description #PCDATA> <!ELEMENT description #PCDATA>
<!ELEMENT privilege ANY> <!ELEMENT privilege ANY>
Clemm, Hopkins, Sedlar, Whitehead [Page 62]
<!-- DAV:current-user-privilege-set Property (Section 5.3) --> <!-- DAV:current-user-privilege-set Property (Section 5.3) -->
<!ELEMENT current-user-privilege-set (privilege*)> <!ELEMENT current-user-privilege-set (privilege*)>
Clemm, Hopkins, Sedlar, Whitehead [Page 57]
<!-- DAV:acl Property (Section 5.4) --> <!-- DAV:acl Property (Section 5.4) -->
<!ELEMENT acl (ace*)> <!ELEMENT acl (ace | inherited-acl)* >
<!ELEMENT inherited-acl (href)>
<!ELEMENT ace (principal, (grant|deny), protected?, inherited?)> <!ELEMENT ace (invert | principal, (grant|deny), protected?,
inherited?)>
<!ELEMENT invert principal>
<!ELEMENT inherited-acl (href)>
<!ELEMENT principal ((href, prop?) <!ELEMENT principal ((href, prop?)
| all | authenticated | unauthenticated | all | authenticated | unauthenticated
| property | self)> | property | self)>
<!ELEMENT prop (see [RFC2518], section 12.11)> <!ELEMENT prop (see [RFC2518], section 12.11)>
<!ELEMENT all EMPTY> <!ELEMENT all EMPTY>
<!ELEMENT authenticated EMPTY> <!ELEMENT authenticated EMPTY>
<!ELEMENT unauthenticated EMPTY> <!ELEMENT unauthenticated EMPTY>
<!ELEMENT property ANY> <!ELEMENT property ANY>
<!ELEMENT self EMPTY> <!ELEMENT self EMPTY>
<!ELEMENT grant (privilege+)> <!ELEMENT grant (privilege+)>
<!ELEMENT deny (privilege+)> <!ELEMENT deny (privilege+)>
<!ELEMENT privilege ANY> <!ELEMENT privilege ANY>
<!ELEMENT protected EMPTY> <!ELEMENT protected EMPTY>
<!ELEMENT inherited (href)> <!ELEMENT inherited (href)>
<!-- DAV:principal-collection-set Property (Section 5.6) --> <!-- DAV:principal-collection-set Property (Section 5.7) -->
<!ELEMENT principal-collection-set (href*)> <!ELEMENT principal-collection-set (href*)>
<!-- DAV:acl-semantics Property (Section 6) --> <!-- DAV:acl-semantics Property (Section 6) -->
<!ELEMENT acl-semantics (ace-combination?, ace-ordering?, allowed- <!ELEMENT acl-semantics (ace-combination?, ace-ordering?,
ace?, required-principal?)> allowed-ace?, required-principal?)>
<!ELEMENT ace-combination <!ELEMENT ace-combination
(first-match | all-grant-before-any-deny | specific-deny- (first-match | all-grant-before-any-deny | specific-deny-
overrides-grant)> overrides-grant)>
Clemm, Hopkins, Sedlar, Whitehead [Page 63]
<!ELEMENT first-match EMPTY> <!ELEMENT first-match EMPTY>
<!ELEMENT all-grant-before-any-deny EMPTY> <!ELEMENT all-grant-before-any-deny EMPTY>
<!ELEMENT specific-deny-overrides-grant EMPTY> <!ELEMENT specific-deny-overrides-grant EMPTY>
<!ELEMENT ace-ordering (deny-before-grant)? > <!ELEMENT ace-ordering (deny-before-grant)? >
<!ELEMENT deny-before-grant EMPTY> <!ELEMENT deny-before-grant EMPTY>
<!ELEMENT allowed-ace (principal-only-one-ace | grant-only)*> <!ELEMENT allowed-ace (principal-only-one-ace | grant-only |
no-invert | no-acl-inherit)*>
<!ELEMENT principal-only-one-ace EMPTY> <!ELEMENT principal-only-one-ace EMPTY>
<!ELEMENT grant-only EMPTY> <!ELEMENT grant-only EMPTY>
<!ELEMENT no-invert EMPTY>
<!ELEMENT no-acl-inherit EMPTY>
<!ELEMENT required-principal <!ELEMENT required-principal
Clemm, Hopkins, Sedlar, Whitehead [Page 58]
(all? | authenticated? | unauthenticated? | self? | href* (all? | authenticated? | unauthenticated? | self? | href*
|property*)> |property*)>
<!-- ACL method preconditions (Section 8.1.1) --> <!-- ACL method preconditions (Section 8.1.1) -->
<!ELEMENT ace-conflict EMPTY> <!ELEMENT no-ace-conflict EMPTY>
<!ELEMENT protected-ace-conflict EMPTY> <!ELEMENT no-protected-ace-conflict EMPTY>
<!ELEMENT inherited-ace-conflict EMPTY> <!ELEMENT no-inherited-ace-conflict EMPTY>
<!ELEMENT too-many-aces EMPTY> <!ELEMENT limited-number-of-aces EMPTY>
<!ELEMENT no-abstract EMPTY>
<!ELEMENT not-supported-privilege EMPTY>
<!ELEMENT missing-required-principal EMPTY>
<!ELEMENT recognized-principal EMPTY>
<!ELEMENT allowed-principal EMPTY>
<!-- REPORTs (Section 9) --> <!-- REPORTs (Section 9) -->
<!ELEMENT acl-principal-props ANY> <!ELEMENT acl-principal-prop-set ANY>
ANY value: a sequence of one or more elements, with at most one ANY value: a sequence of one or more elements, with at most one
DAV:prop element. DAV:prop element.
<!ELEMENT principal-match ((principal-property | self), prop?)> <!ELEMENT principal-match ((principal-property | self), prop?)>
<!ELEMENT principal-property ANY> <!ELEMENT principal-property ANY>
ANY value: an element whose value identifies a property. The ANY value: an element whose value identifies a property. The
expectation is the value of the named property typically contains expectation is the value of the named property typically
an href element that contains the URI of a principal contains an href element that contains the URI of a principal
<!ELEMENT self EMPTY> <!ELEMENT self EMPTY>
<!ELEMENT principal-property-search ((property-search+), prop?) > <!ELEMENT principal-property-search ((property-search+), prop?)
<!ELEMENT property-search (prop, caseless-substring) > >
<!ELEMENT caseless-substring #PCDATA >
Clemm, Hopkins, Sedlar, Whitehead [Page 64]
<!ELEMENT property-search (prop, substring, caseless?) >
<!ELEMENT substring #PCDATA >
<!ELEMENT caseless EMPTY>
<!ELEMENT non-searchable-property (prop) > <!ELEMENT non-searchable-property (prop) >
<!ELEMENT principal-search-property-set (principal-search- <!ELEMENT principal-search-property-set (principal-search-
property*) > property*) >
<!ELEMENT principal-search-property (prop, description) > <!ELEMENT principal-search-property (prop, description) >
20 NOTE TO RFC EDITOR Clemm, Hopkins, Sedlar, Whitehead [Page 65]
As of the writing of this specification, the DeltaV protocol,
described in draft-ietf-deltav-versioning-20, has been approved by
the IESG, but not yet published as an RFC. Within this specification,
the DeltaV protocol is referenced as [RFCxxxx]. These references need
to be replaced with the actual RFC number. As well, the citation in
Section 17.1 also needs to be updated with the correct RFC number,
and the month of issue.
Clemm, Hopkins, Sedlar, Whitehead [Page 59]
 End of changes. 

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