draft-ietf-webdav-acl-06.txt   draft-ietf-webdav-acl-07.txt 
INTERNET-DRAFT Geoffrey Clemm, Rational Software INTERNET-DRAFT Geoffrey Clemm, Rational Software
draft-ietf-webdav-acl-06 Anne Hopkins, Microsoft Corporation draft-ietf-webdav-acl-07 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 December 21, 2001 June 21, 2001 Expires May 9, 2001 November 9, 2001
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 This document is an Internet-Draft and is in full conformance with all
all provisions of Section 10 of RFC2026. provisions of Section 10 of RFC2026.
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Abstract Abstract
This document specifies a set of methods, headers, and message This document specifies a set of methods, headers, and message bodies
bodies that define Access Control extensions to the WebDAV that define Access Control extensions to the WebDAV Distributed
Distributed Authoring Protocol. This protocol permits a client to Authoring Protocol. This protocol permits a client to read and modify
remotely read and modify access control lists that instruct a server access control lists that instruct a server whether to allow or deny
whether to grant or deny operations upon a resource (such as HTTP operations upon a resource (such as HTTP method invocations) by a given
method invocations) by a given principal. 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 Force. Comments on this draft are welcomed, and should be addressed to
to the acl@webdav.org mailing list. Other related documents can be the acl@webdav.org mailing list. Other related documents can be found at
found at http://www.webdav.org/acl/, and http://www.webdav.org/acl/, and http://www.ics.uci.edu/pub/ietf/webdav/.
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...................................................4 1 INTRODUCTION.......................................................5
1.1 Terms.......................................................5 1.1 Terms............................................................7
1.2 Notational Conventions......................................6 1.2 Notational Conventions...........................................8
2 PRINCIPALS.....................................................6 2 PRINCIPALS.........................................................8
3 PRIVILEGES.....................................................7 3 PRIVILEGES.........................................................9
3.1 DAV:read Privilege..........................................8 3.1 DAV:read Privilege..............................................11
3.2 DAV:write Privilege.........................................8 3.2 DAV:write Privilege.............................................11
3.3 DAV:read-acl Privilege......................................9 3.3 DAV:read-acl Privilege..........................................11
3.4 DAV:read-current-user-privilege-set Privilege...............9 3.4 DAV:read-current-user-privilege-set Privilege...................11
3.5 DAV:write-acl Privilege.....................................9 3.5 DAV:write-acl Privilege.........................................12
3.6 DAV:all Privilege...........................................9 3.6 DAV:all Privilege...............................................12
3.7 Aggregation of Predefined Privileges........................9 3.7 Aggregation of Predefined Privileges............................12
4 PRINCIPAL PROPERTIES..........................................10 4 PRINCIPAL PROPERTIES..............................................12
4.1 DAV:alternate-URL..........................................10 4.1 DAV:alternate-URI-set...........................................13
5 ACCESS CONTROL PROPERTIES.....................................10 5 ACCESS CONTROL PROPERTIES.........................................13
5.1 DAV:owner..................................................11 5.1 DAV:owner.......................................................13
5.1.1 Example: Retrieving DAV:owner............................11 5.1.1 Example: Retrieving DAV:owner................................14
5.1.2 Example: An Attempt to Set DAV:owner.....................12 5.1.2 Example: An Attempt to Set DAV:owner.........................15
5.2 DAV:supported-privilege-set................................13 5.2 DAV:supported-privilege-set.....................................16
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.................................................14 Resource.....................................................16
5.3 DAV:current-user-privilege-set.............................15 5.3 DAV:current-user-privilege-set..................................18
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...............................................16 Privileges.........................................................19
5.4 DAV:acl....................................................17 5.4 DAV:acl.........................................................20
5.4.1 ACE Principal............................................17 5.4.1 ACE Principal................................................20
5.4.2 ACE Grant and Deny.......................................18 5.4.2 ACE Grant and Deny...........................................21
5.4.3 ACE Protection...........................................18 5.4.3 ACE Protection...............................................21
5.4.4 ACE Inheritance..........................................18 5.4.4 ACE Inheritance..............................................22
5.4.5 Example: Retrieving a Resource's Access Control List.....19 5.4.5 Example: Retrieving a Resource's Access Control List......22
5.5 DAV:acl-semantics..........................................20 5.5 DAV:acl-semantics...............................................23
5.5.1 Example: Retrieving DAV:acl-semantics....................21 5.5.1 Example: Retrieving DAV:acl-semantics........................24
5.6 DAV:principal-collection-set...............................22 5.6 DAV:principal-collection-set....................................25
5.6.1 Example: Retrieving DAV:principal-collection-set.........22 5.6.1 Example: Retrieving DAV:principal-collection-set.............26
5.7 Example: PROPFIND to retrieve access control properties....23 5.7 Example: PROPFIND to retrieve access control properties.........27
6 ACL SEMANTICS.................................................27 6 ACL SEMANTICS.....................................................30
6.1 ACE Combination............................................27 6.1 ACE Combination.................................................31
6.1.1 DAV:first-match ACE Combination..........................27 6.1.1 DAV:first-match ACE Combination..............................31
6.1.2 DAV:all-grant-before-any-deny ACE Combination............27 6.1.2 DAV:all-grant-before-any-deny ACE Combination................31
6.1.3 DAV:specific-deny-overrides-grant ACE Combination........27 6.1.3 DAV:specific-deny-overrides-grant ACE Combination............31
6.2 ACE Ordering...............................................28 6.2 ACE Ordering....................................................31
6.2.1 DAV:deny-before-grant ACE Ordering.......................28 6.2.1 DAV:deny-before-grant ACE Ordering...........................32
6.3 Allowed ACE................................................28 6.3 Allowed ACE.....................................................32
6.3.1 DAV:principal-only-one-ace ACE Constraint................28 6.3.1 DAV:principal-only-one-ace ACE Constraint....................32
6.3.2 DAV:grant-only ACE Constraint............................28
6.4 Required Principals........................................28
Clemm, Hopkins, Sedlar, Whitehead [Page 2] Clemm, Hopkins, Sedlar, Whitehead [Page 2]
7 ACCESS CONTROL AND EXISTING METHODS...........................29 6.3.2 DAV:grant-only ACE Constraint................................32
7.1 OPTIONS....................................................29 6.4 Required Principals.............................................32
7.1.1 Example - OPTIONS........................................29
7.2 MOVE.......................................................29
7.3 COPY.......................................................29
8 ACCESS CONTROL METHODS........................................29 7 ACCESS CONTROL AND EXISTING METHODS...............................32
8.1 ACL........................................................29 7.1 OPTIONS.........................................................33
8.1.1 ACL Preconditions........................................30 7.1.1 Example - OPTIONS............................................33
8.1.2 Example: the ACL method..................................31 7.2 MOVE............................................................33
8.1.3 Example: ACL method failure due to protected ACE 7.3 COPY............................................................33
conflict ................................................32 7.4 DELETE..........................................................33
8.1.4 Example: ACL method failure due to an inherited ACE 7.5 LOCK............................................................34
conflict ................................................33
8.1.5 Example: ACL method failure due to an attempt to set
grant and deny in a single ACE ..........................34
9 ACCESS CONTROL REPORTS........................................35 8 ACCESS CONTROL METHODS............................................34
9.1 REPORT Method..............................................35 8.1 ACL.............................................................34
9.2 DAV:acl-principal-props Report.............................36 8.1.1 ACL Preconditions............................................34
9.2.1 Example: DAV:acl-principal-props Report..................36 8.1.2 Example: the ACL method......................................36
9.3 DAV:principal-match REPORT.................................37 8.1.3 Example: ACL method failure due to protected ACE conflict....37
9.3.1 Example: DAV:principal-match REPORT......................38 8.1.4 Example: ACL method failure due to an inherited ACE conflict 38
8.1.5 Example: ACL method failure due to an attempt to set grant
and deny in a single ACE.....................................39
10 XML PROCESSING..............................................39 9 ACCESS CONTROL REPORTS............................................40
9.1 REPORT Method...................................................40
9.2 DAV:acl-principal-props Report..................................40
9.2.1 Example: DAV:acl-principal-props Report......................40
9.3 DAV:principal-match REPORT......................................42
9.3.1 Example: DAV:principal-match REPORT..........................43
9.4 DAV:principal-property-search REPORT............................44
9.4.1 Matching.....................................................45
9.4.2 Example: successful DAV:principal-property-search REPORT.....46
9.4.3 Example: Unsuccessful DAV:principal-property-search REPORT...48
9.5 DAV:principal-search-property-set REPORT........................49
9.5.1 Example: DAV:principal-search-property-set REPORT............50
11 INTERNATIONALIZATION CONSIDERATIONS.........................39 10 XML PROCESSING..................................................51
12 SECURITY CONSIDERATIONS.....................................40 11 INTERNATIONALIZATION CONSIDERATIONS.............................51
12.1 Increased Risk of Compromised Users........................40
12 SECURITY CONSIDERATIONS.........................................52
12.1 Increased Risk of Compromised Users...........................52
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.................................................40 Privileges....................................................52
12.3 No Foreknowledge of Initial ACL............................41 12.3 No Foreknowledge of Initial ACL...............................53
13 AUTHENTICATION..............................................41 13 AUTHENTICATION..................................................53
14 IANA CONSIDERATIONS.........................................42 14 IANA CONSIDERATIONS.............................................53
15 INTELLECTUAL PROPERTY.......................................42 15 INTELLECTUAL PROPERTY...........................................54
16 ACKNOWLEDGEMENTS............................................42 16 ACKNOWLEDGEMENTS................................................54
17 REFERENCES..................................................43 Clemm, Hopkins, Sedlar, Whitehead [Page 3]
17.1 Normative References.......................................43
17.2 Informational References...................................43
18 AUTHORS' ADDRESSES..........................................43 17 REFERENCES......................................................55
17.1 Normative References..........................................55
17.2 Informational References......................................56
19 APPENDICIES.................................................44 18 AUTHORS' ADDRESSES..............................................56
19.1 XML Document Type Definition...............................44
20 NOTE TO RFC EDITOR..........................................46 19 APPENDICIES.....................................................57
19.1 XML Document Type Definition..................................57
20 NOTE TO RFC EDITOR..............................................59
Clemm, Hopkins, Sedlar, Whitehead [Page 4]
Clemm, Hopkins, Sedlar, Whitehead [Page 3]
1 INTRODUCTION 1 INTRODUCTION
The goal of the WebDAV access control extensions is to provide The goal of the WebDAV access control extensions is to provide an
an interoperable mechanism for handling discretionary access interoperable mechanism for handling discretionary access control for
control for content in WebDAV servers. WebDAV access control content and metadata managed by WebDAV servers. WebDAV access
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 simple as that of a UNIX file system, as well as more sophisticated
sophisticated models. The underlying principle of access models. The underlying principle of access control is that who you
control is that who you are determines how you can access a are determines what operations you can perform on a resource. The
resource. The "who you are" is defined by a "principal" "who you are" is defined by a "principal" identifier; users, client
identifier; users, client software, servers, and groups of the software, servers, and groups of the previous have principal
previous have principal identifiers. The "how" is determined by identifiers. The "operations you can perform" is determined by a
a single "access control list" (ACL) associated with a single "access control list" (ACL) associated with a resource. An
resource. An ACL contains a set of "access control entries" ACL contains a set of "access control entries" (ACEs), where each ACE
(ACEs), where each ACE specifies a principal and a set of specifies a principal and a set of privileges that are either granted
privileges that are either granted or denied to that principal. or denied to that principal. When a principal submits an operation
When a principal submits an operation (such as an HTTP or (such as an HTTP or WebDAV method) to a resource for execution, the
WebDAV method) to a resource for execution, the server server evaluates the ACEs in the ACL to determine if the principal
evaluates the ACEs in the ACL to determine if the principal has has permission for that operation.
permission for that operation.
This specification intentionally omits discussion of Since every ACE contains the identifier of a principal, client
authentication, as the HTTP protocol already has a number of software operated by a human must provide a mechanism for selecting
authentication mechanisms [RFC2617]. Some authentication this principal. This specification uses http(s) scheme URLs to
mechanism (such as HTTP Digest Authentication, which all WebDAV identify principals, which are represented as WebDAV-capable
compliant implementations are required to support) must be resources. There is no guarantee that the URLs identifying principals
available to validate the identity of a principal. will be meaningful to a human. For example,
http://www.dav.org/u/256432 and http://www.dav.org/people/Greg.Stein
are both valid URLs that could 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
problem of determining exactly which principal's operations are being
described in a given ACE. It is impossible for a client 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/u/256432. That is, a client has no mechanism for
determining that two URLs identify the same principal resource. As a
result, this specification requires clients to use just one of the
many possible URLs for a principal when creating ACEs. A client can
discover this URL by retrieving the DAV:principal-URL property
(Section 4.2) from a principal resource. No matter which of the
principal's URLs is used with PROPFIND, the property always returns
the same URL.
Once a system has hundreds to thousands of principals, the problem
arises of how to allow a human operator of client software to select
just one of these principals. One approach is to use broad collection
Clemm, Hopkins, Sedlar, Whitehead [Page 5]
hierarchies to spread the principals over a large number of
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,
creating collections /a/a/, /a/b/, Ó, /a/z/, such that a principal
with last name "Stein" would appear at /s/t/Stein. In effect, this
pre-computes a common query, search on last name, and encodes it into
a hierarchy. The drawback with this scheme is that it handles only a
small set of predefined queries, and drilling down through the
collection hierarchy adds unnecessary steps (navigate down/up) when
the user already knows the principal's name. While organizing
principal URLs into a hierarchy is a valid namespace organization,
users should not be forced to navigate this hierarchy to select a
principal.
This specification provides the capability to perform substring
searches on a small set of properties on the resources representing
principals. This permits searches based on last name, first name,
user name, job title, etc. Two separate searches are supported, via
the REPORT method, one to search principal resources, the other to
determine which properties may be searched at all.
Once a principal has been identified in an ACE, a server evaluating
that ACE must know the identity of the principal making a protocol
request, and must validate that that principal is who they claim to
be, a process known as authentication. This specification
intentionally omits discussion of authentication, as the HTTP
protocol already has a number of authentication mechanisms [RFC2617].
Some authentication mechanism (such as HTTP Digest Authentication,
which all WebDAV compliant implementations are 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 * Access control that applies only to a particular property on a
on a resource (excepting the access control properties resource (excepting the access control properties DAV:acl and
DAV:acl and DAV:current-user-privilege-set), rather than DAV:current-user-privilege-set), rather than the entire
the entire resource, resource,
* Role-based security (where a role can be seen as a * Role-based security (where a role can be seen as a dynamically
dynamically defined collection of principals), defined collection of principals),
* Specification of the ways an ACL on a resource is * Specification of the ways an ACL on a resource is initialized,
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 * Creation and maintenance of resources representing people or
or computational agents (principals), and groups of these. computational agents (principals), and groups of these.
This specification is organized as follows. Section 1.1 defines This specification is organized as follows. Section 1.1 defines key
key concepts used throughout the specification, and is followed concepts used throughout the specification, and is followed by a more
by more in-depth discussion of principals (Section 2), and
privileges (Section 3). Properties defined on principals are
specified in Section 4, and access control properties for
content resources are specified in Section 5. The semantics of
access control lists are described in Section 6, including
sections on ACE combination (Section 6.1), ACE ordering
Clemm, Hopkins, Sedlar, Whitehead [Page 4] Clemm, Hopkins, Sedlar, Whitehead [Page 6]
(Section 6.2), and principals required to be present in an ACE in-depth discussion of principals (Section 2), and privileges
(Section 6.4). Client discovery of access control capability (Section 3). Properties defined on principals are specified in
using OPTIONS is described in Section 7.1, and the access Section 4, and access control properties for content resources are
control setting method, ACL, is specified in Section 8. specified in Section 5. The semantics of access control lists are
Internationalization considerations (Section 11) and security described in Section 6, including sections on ACE combination
considerations (Section 12) round out the specification. An (Section 6.1), ACE ordering (Section 6.2), and principals required to
appendix (Section 19.1) provides an XML Document Type be present in an ACE (Section 6.4). Client discovery of access
Definition (DTD) for the XML elements defined in the control capability using OPTIONS is described in Section 7.1.
specification. Interactions between access control functionality and existing HTTP
and WebDAV methods are described in the remainder of Section 7. The
access control setting method, ACL, is specified in Section 8. Four
reports that provide limited server-side searching capabilities are
described in Section 9. A note on XML processing (Section 10),
Internationalization considerations (Section 11), security
considerations (Section 12), and a note on authentication (Section
13) round out the specification. An appendix (Section 19.1) provides
an XML 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 principal collection
A "principal collection" is a group of principals, and is A "principal collection" is a group of principals, and is
represented in this protocol by a WebDAV collection containing represented in this protocol by a WebDAV collection containing HTTP
HTTP resources that represent principals, and principal resources that represent principals, and principal collections.
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)
An "ACL" is a list of access control elements that define Clemm, Hopkins, Sedlar, Whitehead [Page 7]
access control to a particular resource. An "ACL" is a list of access control elements that define access
control to a particular resource.
access control element (ace) access control element (ACE)
An "ace" either grants or denies a particular set of (non- An "ACE" either grants or denies a particular set of (non-abstract)
abstract) privileges for a particular principal. privileges for a particular principal.
Clemm, Hopkins, Sedlar, Whitehead [Page 5] inherited ACE
inherited ace
An "inherited ace" is an ace that is dynamically shared from An "inherited ACE" is an ACE that is dynamically shared from the
the ACL of another resource. When a shared ACE changes on the ACL of another resource. When a shared ACE changes on the primary
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 A "protected property" is one whose value cannot be updated except
except by a method explicitly defined as updating that specific by a method explicitly defined as updating that specific property.
property. In particular, a protected property cannot be In particular, a protected property cannot be updated with a
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 The augmented BNF used by this document to describe protocol elements
elements is described in Section 2.1 of [RFC2616]. Because this is described in Section 2.1 of [RFC2616]. Because this augmented BNF
augmented BNF uses the basic production rules provided in uses the basic production rules provided in Section 2.2 of [RFC2616],
Section 2.2 of [RFC2616], those rules apply to this document as those rules apply to this document as well.
well.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
"OPTIONAL" in this document are to be interpreted as described document are to be interpreted as described in [RFC2119].
in [RFC2119].
Definitions of XML elements in this document use XML element Definitions of XML elements in this document use XML element type
type declarations (as found in XML Document Type Declarations), declarations (as found in XML Document Type Declarations), described
described in Section 3.2 of [REC-XML]. in Section 3.2 of [REC-XML]. When an XML element type in the "DAV:"
namespace is referenced in this document outside of the 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 A principal is a network resource that represents a distinct human or
human or computational actor that initiates access to network computational actor that initiates access to network resources. Users
resources. On many implementations, users and groups are and groups are represented as principals in many implementations;
represented as principals; other types of principals are also other types of principals are also possible. A URI of any scheme MAY
possible. A URI of any scheme MAY be used to identify a be used to identify a principal resource. However, servers
principal resource. However, servers implementing this implementing this specification MUST expose principal resources at an
specification MUST expose principal resources at an http(s) http(s) URL, which is a privileged scheme that points to resources
URL, which is a privileged scheme that points to resources that that have additional properties, as described in Section 4. So, a
have additional properties, as described in Section 4. So, a principal resource can have multiple URIs, one of which has to be an
principal resource can have multiple URI identifiers, one of http(s) scheme URL. Although an implementation SHOULD support
which has to be an http(s) scheme URL. Although an
implementation SHOULD support PROPFIND and MAY support
PROPPATCH to access and modify information about a principal,
it is not required to do so.
A principal resource may or may not be a collection. If a Clemm, Hopkins, Sedlar, Whitehead [Page 8]
person or computational agent matches a principal resource that PROPFIND and MAY support PROPPATCH to access and modify information
is contained by a collection principal, they also match the about a principal, it is not required to do so.
collection principal. This definition is recursive, and hence
if a person or computational agent matches a collection
principal that is the child of another collection principal,
they also match the parent collection principal. Membership in
a collection principal is also recursive, so a principal in a
collection principal GRPA contained by collection principal
Clemm, Hopkins, Sedlar, Whitehead [Page 6] A principal resource may or may not be a collection. If a person or
GRPB is a member of both GRPA and GRPB. Implementations not computational agent matches a principal resource that is contained by
supporting recursive membership in principal collections can a collection principal, they also match the collection principal.
return an error if the client attempts to bind collection This definition is recursive, and hence if a person or computational
principals into other collection principals. agent matches a collection principal that is the child of another
collection principal, they also match the parent collection
principal. Membership in a collection principal is also recursive, so
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 Servers that support aggregation of principals (e.g. groups of users
users or other groups) MUST manifest them as collection or other groups) MUST manifest them as collection principals. At
principals. At minimum, principals and collection principals minimum, principals and collection principals MUST support the
MUST support the OPTIONS and PROPFIND methods. OPTIONS and PROPFIND methods.
Implementer's Note: Collection principals are first and Implementer's Note: Collection principals are first and foremost
foremost WebDAV collections. Therefore they contain WebDAV collections. Therefore they contain resources as members.
resources as members. Since there is no requirement that all Since there is no requirement that all members of a collection
members of a collection principal need be principals, it is principal need be principals, it is possible for a collection
possible for a collection principal to have non-principals principal to have non-principals as members. When enumerating the
as members. When enumerating the principals-only membership principals-only membership of a collection principal, it is
of a collection principal, it is necessary to retrieve the necessary to retrieve the DAV:resourcetype property and check it
DAV:resourcetype property and check it for the DAV:principal for the DAV:principal XML element (described in Section 4). If the
XML element (described in Section 4). If the DAV:principal DAV:principal XML element is not present, the resource is not a
XML element is not present, the resource is not a principal principal and may be ignored for the purposes of determining the
and may be ignored for the purposes of determining the
principals-only membership of the collection principal. principals-only membership of the collection principal.
For example, the collection principal /FOO/ has two members, For example, the collection principal /FOO/ has two members, Bar
Bar and Baz. Bar is a principal but Baz is not. Therefore and Baz. Bar is a principal but Baz is not. Therefore when
when determining which principals belong to the collection determining which principals belong to the collection principal
principal /FOO/, a client would enumerate the membership /FOO/, a client would enumerate the membership using PROPFIND
using PROPFIND while asking for the DAV:resourcetype while asking for the DAV:resourcetype property, and see that only
property, and see that only Bar has the DAV:principal XML Bar has the DAV:principal XML element. Therefore, only Bar is the
element. Therefore, only Bar is the only principal that is a only principal that is a member of the collection principal /FOO/.
member of the collection principal /FOO/.
3 PRIVILEGES 3 PRIVILEGES
Ability to perform a given method on a resource SHOULD be Ability to perform a given method on a resource SHOULD be controlled
controlled by one or more privileges. Authors of protocol by one or more privileges. Authors of protocol extensions that
extensions that define new HTTP methods SHOULD specify which define new HTTP methods SHOULD specify which privileges (by defining
privileges (by defining new privileges, or mapping to ones new privileges, or mapping to ones below) are required to perform the
below) are required to perform the method. A principal with no method. A principal with no privileges to a resource SHOULD be
privileges to a resource SHOULD be denied any HTTP access to denied any HTTP access to that resource, unless the principal matches
that resource.
Privileges may be containers of other privileges, in which case Clemm, Hopkins, Sedlar, Whitehead [Page 9]
they are termed aggregate privileges. If a principal is an ACE constructed using the DAV:all, DAV:authenticated, or
granted or denied an aggregate privilege, it is semantically DAV:unauthenticated pseudo-principals (see Section 5.4.1).
equivalent to granting or denying each of the aggregated
privileges individually. For example, an implementation may Privileges may be containers of other privileges, in which case they
define add-member and remove-member privileges that control the are termed aggregate privileges. If a principal is granted or denied
ability to add and remove an internal member of a collection. an aggregate privilege, it is semantically equivalent to granting or
Since these privileges control the ability to update the state denying each of the aggregated privileges individually. For example,
of a collection, these privileges would be aggregated by the an implementation may define add-member and remove-member privileges
that control the ability to add and remove an internal member of a
collection. Since these privileges control the ability to update the
state of a collection, these privileges would be aggregated by the
DAV:write privilege on a collection, and granting the DAV:write DAV:write privilege on a collection, and granting the DAV:write
privilege on a collection would also grant the add-member and privilege on a collection would also grant the add-member and remove-
remove-member privileges. member privileges.
Clemm, Hopkins, Sedlar, Whitehead [Page 7] Privileges may have the quality of being abstract, in which case they
Privileges may have the quality of being abstract, in which cannot be set in an ACE. Aggregate and non-aggregate privileges are
case they cannot be set in an ACE. Aggregate and non-aggregate both capable of being abstract. Abstract privileges are useful for
privileges are both capable of being abstract. Abstract modeling privileges that otherwise would not be exposed via the
privileges are useful for modeling privileges that otherwise protocol. Abstract privileges also provide server implementations
would not be exposed via the protocol. Abstract privileges also with flexibility in implementing the privileges defined in this
provide server implementations with flexibility in implementing specification. For example, if a server is incapable of separating
the privileges defined in this specification. For example, if the read resource capability from the read ACL capability, it can
a server is incapable of separating the read resource still model the DAV:read and DAV:read-acl privileges defined in this
capability from the read ACL capability, it can still model the specification by declaring them abstract, and containing them within
DAV:read and DAV:read-acl privileges defined in this a non-abstract aggregate privilege (say, read-all) that holds
specification by declaring them abstract, and containing them DAV:read, and DAV:read-acl. In this way, it is possible to set the
within a non-abstract aggregate privilege (say, read-all) that aggregate privilege, read-all, thus coupling the setting of DAV:read
holds DAV:read, and DAV:read-acl. In this way, it is possible and DAV:read-acl, but it is not possible to set DAV:read, or
to set the aggregate privilege, read-all, thus coupling the DAV:read-acl individually. Since aggregate privileges can be
setting of DAV:read and DAV:read-acl, but it is not possible to abstract, it is also possible to use abstract privileges to group or
set DAV:read, or DAV:read-acl individually. Since aggregate organize non-abstract privileges. Privilege containment loops are not
privileges can be abstract, it is also possible to use abstract allowed, hence a privilege MUST NOT contain itself. For example,
privileges to group or organize non-abstract privileges. DAV:read cannot contain DAV:read.
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 The set of privileges that apply to a particular resource may vary
vary with the DAV:resourcetype of the resource, as well as with the DAV:resourcetype of the resource, as well as between
between different server implementations. To promote different server implementations. To promote interoperability,
interoperability, however, this specification defines a set of however, this specification defines a set of well-known privileges
well-known privileges (e.g. DAV:read,DAV:write, DAV:read-acl, (e.g. DAV:read, DAV:write, DAV:read-acl, DAV:write-acl, DAV:read-
DAV:write-acl, DAV:read-current-user-privilege-set, and current-user-privilege-set, and DAV:all), which can at least be used
DAV:all), which can at least be used to classify the other to classify the other privileges defined on a particular resource.
privileges defined on a particular resource. The access The access permissions on null resources (defined in [RFC2518],
permissions on null and lock-null resources (defined in Section 3) are solely those they inherit (if any), and they are not
[RFC2518], Sections 3 and 7.4) are solely those they inherit discoverable (i.e., the access control properties specified in
(if any), and they are not discoverable (i.e., the access Section 5 are not defined on null resources). On the transition from
control properties specified in Section 5 are not defined on null to stateful resource, the initial access control list is set by
null and lock-null resources). On the transition from null or the server's default ACL value policy (if any).
lock-null to a stateful resource, the initial access 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]
implementations MUST NOT use the DAV: namespace, and instead should
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 The read privilege controls methods that return information about the
about the state of the resource, including the resource's state of the resource, including the resource's properties. Affected
properties. Affected methods include GET and PROPFIND. methods include GET and PROPFIND. Additionally, the read privilege
Additionally, the read privilege MAY control the OPTIONS MAY control the OPTIONS method.
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, The write privilege controls methods that modify the content, dead
dead properties, or (in the case of a collection) membership of properties, or (in the case of a collection) membership of the
the resource, such as PUT and PROPPATCH. Note that state resource, such as PUT and PROPPATCH. Note that state modification is
modification is also controlled via locking (see section 5.3 of 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 8] locking requirements are satisfied.
[WEBDAV]), so effective write access requires that both write
privileges and write locking requirements are satisfied.
<!ELEMENT write EMPTY> <!ELEMENT write EMPTY>
3.3 DAV:read-acl Privilege 3.3 DAV:read-acl Privilege
The DAV:read-acl privilege controls the use of PROPFIND to The DAV:read-acl privilege controls the use of PROPFIND to retrieve
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 3.4 DAV:read-current-user-privilege-set Privilege
The DAV:read-current-user-privilege-set privilege controls the The DAV:read-current-user-privilege-set privilege controls the use of
use of PROPFIND to retrieve the DAV:current-user-privilege-set PROPFIND to retrieve the DAV:current-user-privilege-set property of
property of the resource. the resource.
Clients are intended to use this property to visually indicate Clients are intended to use this property to visually indicate in
in their UI items that are dependent on the permissions of a their UI items that are dependent on the permissions of a resource,
resource, for example, by graying out resources that are not for example, by graying out resources that are not writeable.
writeable.
This privilege is separate from DAV:read-acl because there is a This privilege is separate from DAV:read-acl because there is a need
need to allow most users access to the privileges permitted the to allow most users access to the privileges permitted the current
current user (due to its use in creating the UI), while the user (due to its use in creating the UI), while the full ACL contains
full ACL contains information that may not be appropriate for information that may not be appropriate for the current authenticated
the current authenticated user. As a result, the set of users user. As a result, the set of users who can view the full ACL is
who can view the full ACL is expected to be much smaller than expected to be much smaller than those who can read the current user
those who can read the current user privilege set, and hence privilege set, and hence distinct privileges are needed for each.
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]
3.5 DAV:write-acl Privilege 3.5 DAV:write-acl Privilege
The DAV:write-acl privilege controls use of the ACL method to The DAV:write-acl privilege controls use of the ACL method to modify
modify the DAV:acl property of the resource. the DAV:acl property of the resource.
<!ELEMENT write-acl EMPTY> <!ELEMENT write-acl EMPTY>
3.6 DAV:all Privilege 3.6 DAV:all Privilege
DAV:all is an aggregate privilege that contains the entire set DAV:all is an aggregate privilege that contains the entire set of
of privileges that apply to the resource. privileges that can be applied to the resource.
<!ELEMENT all EMPTY> <!ELEMENT all EMPTY>
3.7 Aggregation of Predefined Privileges 3.7 Aggregation 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 3.1-3.6) subject to the
following limitations: following limitations:
Clemm, Hopkins, Sedlar, Whitehead [Page 9] DAV:read-acl MUST NOT contain DAV:read, DAV:write, DAV:write-acl, or
DAV:read-acl MUST NOT contain DAV:read, DAV:write, DAV:write- DAV:read-current-user-privilege-set.
acl, or DAV:read-current-user-privilege-set.
DAV:write-acl MUST NOT contain DAV:write, DAV:read, DAV:read- DAV:write-acl MUST NOT contain DAV:write, DAV:read, DAV:read-acl, or
acl, or DAV:read-current-user-privilege-set. 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, or DAV:write-acl.
4 PRINCIPAL PROPERTIES 4 PRINCIPAL PROPERTIES
Principals are manifested to clients as an HTTP resource, Principals are manifested to clients as a WebDAV resource, identified
identified by a URL. A principal MUST have a DAV:displayname by a URL. A principal MUST have a DAV:displayname property (defined
property (defined in Section 13.2 of [RFC2518]), and a in Section 13.2 of [RFC2518]), and a DAV:resourcetype property
DAV:resourcetype property (defined in Section 13.9 of (defined in Section 13.9 of [RFC2518]). Additionally, a principal
[RFC2518]). Additionally, a principal MUST report the MUST report the DAV:principal empty XML element in the value of the
DAV:principal empty XML element in the value of the DAV:resourcetype property in addition to all other reported elements.
DAV:resourcetype property in addition to all other reported For example, a collection principal would report DAV:collection and
elements. For example, a collection principal 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
SHOULD NOT be returned by a PROPFIND allprop request (as
defined in Section 12.14.1 of [RFC2518]).
4.1 DAV:alternate-URL Clemm, Hopkins, Sedlar, Whitehead [Page 12]
SHOULD NOT be returned by a PROPFIND allprop request (as defined in
Section 12.14.1 of [RFC2518]).
This protected property, if non-empty, contains the URIs of 4.1 DAV:alternate-URI-set
network resources with additional descriptive information about
the principal. This property identifies one or more additional
network resources (i.e., it contains one or more URIs) that may
be consulted by a client to gain additional knowledge
concerning a principal. Two potential uses for this property
are to store an ldap [RFC2255] or mailto [RFC2368] scheme URL.
Support for this property is REQUIRED, and the value is empty
if no alternate URL exists for the principal. .
<!ELEMENT alternate-URL (href*)> This protected property, if non-empty, contains the URIs of network
resources with additional descriptive information about the
principal. This property identifies additional network resources
(i.e., it contains one or more URIs) that may be consulted by a
client to gain additional knowledge concerning a principal. One
expected use for this property is the storage of an ldap [RFC2255]
scheme URL. A user-agent encountering an ldap URL could use LDAP
[RFC2589] to retrieve additional machine-readable directory
information about the principal, and display that information in its
user interface. Support for this property is REQUIRED, and the value
is empty if no alternate URI exists for the principal.
5 ACCESS CONTROL PROPERTIES <!ELEMENT alternate-URI-set (href*)>
This specification defines a number of new properties for 4.2 DAV:principal-URL
WebDAV resources. Access control properties may be retrieved
just like other WebDAV properties, using the PROPFIND method.
Since it is expensive, for many servers, to retrieve access
Clemm, Hopkins, Sedlar, Whitehead [Page 10] This protected property contains the URL that MUST be used to
control information, a PROPFIND allprop request (as defined in identify this principal in an ACL request.
Section 12.14.1 of [RFC2518]) SHOULD NOT return the names and
values of the properties defined in this section.
HTTP resources that support the WebDAV Access Control Protocol <!ELEMENT principal-URL (href)>
MUST contain the following properties. Null, and lock-null
resources (described in Section 7.4 of [RFC2518]) MUST NOT 5 ACCESS CONTROL PROPERTIES
contain the following properties:
This specification defines a number of new properties for WebDAV
resources. Access control properties may be retrieved just like
other WebDAV properties, using the PROPFIND method. Since it is
expensive, for many servers, to retrieve access control information,
a PROPFIND allprop request (as defined in Section 12.14.1 of
[RFC2518]) SHOULD NOT return the names and values of the properties
defined in this section.
HTTP resources that support the WebDAV Access Control Protocol MUST
contain the following properties. Null resources (described in
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 This protected property identifies a particular principal as being
being the "owner" of the resource. Since the owner of a the "owner" of the resource. Since the owner of a resource often has
resource often has special access control capabilities (e.g., special access control capabilities (e.g., the owner frequently has
the owner frequently has permanent DAV:write-acl privilege), permanent DAV:write-acl privilege), clients might display the
clients might display the resource owner in their user resource owner in their user interface.
interface.
<!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 This example shows a client request for the value of the DAV:owner
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 http://www.webdav.org/papers/. The principal making the request is
is authenticated using Digest authentication. The value of authenticated using Digest authentication. The value of DAV:owner is
DAV:owner is the URL http://www.webdav.org/_acl/users/gstein, the URL http://www.webdav.org/_acl/users/gstein, wrapped in the
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",
realm="jim@webdav.org", nonce="...", realm="jim@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:owner/> <D:owner/>
</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
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:"> <D:multistatus xmlns:D="DAV:">
Clemm, Hopkins, Sedlar, Whitehead [Page 11]
<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:status>HTTP/1.1 200 OK</D:status>
<D:prop> <D:prop>
<D:owner> <D:owner>
<D:href> <D:href>http://www.webdav.org/_acl/users/gstein</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:propstat> </D:propstat>
</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 The following example shows a client request to modify the value of
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) property, the server responds with a 207 (Multi-Status) response that
response that contains a 403 (Forbidden) status code for the contains a 403 (Forbidden) status code for the act of setting
act of setting DAV:owner. [RFC2518], Section 8.2.1 describes DAV:owner. Section 8.2.1 of [RFC2518] describes PROPPATCH status code
PROPPATCH status code information, and Section 11 describes the information, and Section 11 of [RFC2518] describes the Multi-Status
Multi-Status response. 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="...",
uri="/papers/", response="...", opaque="..." uri="/papers/", response="...", opaque="..."
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
<D:propertyupdate xmlns:D="DAV:"> <D:propertyupdate xmlns:D="DAV:">
<D:set> <D:set>
<D:prop> <D:prop>
<D:owner> <D:owner>
<D:href> <D:href>http://www.webdav.org/_acl/users/jim</D:href>
http://www.webdav.org/_acl/users/jim
</D:href>
</D:owner> </D:owner>
</D:prop> </D:prop>
</D:set> </D:set>
</D:propertyupdate> </D:propertyupdate>
>> 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 12]
<?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:status>HTTP/1.1 403 Forbidden</D:status>
<D:prop><D:owner/></D:prop> <D:prop><D:owner/></D:prop>
</D:propstat> <D:status>HTTP/1.1 403 Forbidden</D:status>
<D:responsedescription>Failure to set protected property <D:responsedescription>Failure to set protected property
(DAV:owner) (DAV:owner)
</D:responsedescription> </D:responsedescription>
</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 This is a protected property that identifies the privileges defined
defined for the resource. 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 of a resource MUST NOT be used in an ACE An abstract privilege MUST NOT be used in an ACE for that resource.
for that resource. Servers MUST fail an attempt to set an Servers MUST fail an attempt to set an abstract privilege.
abstract privilege.
<!ELEMENT abstract EMPTY> <!ELEMENT abstract EMPTY>
A description is a human-readable description of what this A description is a human-readable description of what this privilege
privilege controls access to. controls access to. Servers MUST indicate the human language of the
description using the xml:lang attribute and SHOULD consider the HTTP
Accept-Language request header when selecting one of multiple
available languages.
<!ELEMENT description #PCDATA> <!ELEMENT description #PCDATA>
It is envisioned that a WebDAV ACL-aware administrative client It is envisioned that a WebDAV ACL-aware administrative client would
would list the supported privileges in a dialog box, and allow list the supported privileges in a dialog box, and allow the user to
the user to choose non-abstract privileges to apply in an ACE. choose non-abstract privileges to apply in an ACE. The privileges
The privileges tree is useful programmatically to map well- tree is useful programmatically to map well-known privileges (defined
known privileges (defined by WebDAV or other standards groups) by WebDAV or other standards groups) into privileges that are
into privileges that are supported by any particular server supported by any particular server implementation. The privilege
implementation. The privilege tree also serves to hide tree also serves to hide complexity in implementations allowing large
complexity in implementations allowing large number of number of privileges to be defined by displaying aggregates to the
privileges to be defined by displaying aggregates to the user. user.
Clemm, Hopkins, Sedlar, Whitehead [Page 13] 5.2.1 Example: Retrieving a List of Privileges Supported on a Resource
5.2.1 Example: Retrieving a List of Privileges Supported on a
Resource
This example shows a client request for the DAV:supported- This example shows a client request for the DAV:supported-privilege-
privilege-set property on the resource set property on the resource http://www.webdav.org/papers/. The value
http://www.webdav.org/papers/. The value of the DAV:supported- of the DAV:supported-privilege-set property is a tree of supported
privilege-set property is a tree of supported privileges: privileges:
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 (abstract)
+-- DAV:write (aggregate) +-- DAV:write (aggregate)
| |
+-- DAV:write-acl (abstract) +-- DAV:write-acl (abstract)
This privilege tree is not normative, and many possible This privilege tree is not normative, and many possible privilege
privilege trees are possible. 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:supported-privilege-set/> <D:supported-privilege-set/>
</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
<?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:status>HTTP/1.1 200 OK</D:status>
<D:prop> <D:prop>
<D:supported-privilege-set> <D:supported-privilege-set>
Clemm, Hopkins, Sedlar, Whitehead [Page 14]
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <D:all/> </D:privilege> <D:privilege> <D:all/> </D:privilege>
<D:abstract/> <D:abstract/>
<D:description>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>Read any object</D:description>
Clemm, Hopkins, Sedlar, Whitehead [Page 17]
<D:description xml:lang="en">Read any
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>Read ACL</D:description> <D:description xml:lang="en">Read
ACL</D:description>
</D:supported-privilege> </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>Read current user privilege set <D:description xml:lang="en">Read current user
property</D:description> privilege set property</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:description>Write any object</D:description> <D:description xml:lang="en">Write any
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>Write ACL</D:description> <D:description xml:lang="en">Write
ACL</D:description>
<D:abstract/> <D:abstract/>
</D:supported-privilege> </D:supported-privilege>
</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: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 DAV:current-user-privilege-set is a protected property containing the
containing the exact set of privileges (as computed by the exact set of privileges (as computed by the server) granted to the
server) granted to the currently authenticated HTTP user. currently authenticated HTTP user. Aggregate privileges and their
Aggregate privileges and their contained privileges are listed. contained privileges are listed. A user-agent can use the value of
A user-agent can use the value of this property to adjust its this property to adjust its user interface to make actions
user interface to make actions inaccessible (e.g., by graying inaccessible (e.g., by graying out a menu item or button) for which
out a menu item or button) for which the current principal does the current principal does not have permission. This is particularly
not have permission. This is particularly useful for an access useful for an access control user interface, which can be constructed
control user interface, which can be constructed without without knowing the ACE combining semantics of the server. This
knowing the ACE combining semantics of the server. This property is also useful for determining what operations the current
property is also useful for determining what operations the principal can perform, without having to actually execute an
current principal can perform, without having to actually operation.
execute an operation.
Clemm, Hopkins, Sedlar, Whitehead [Page 18]
<!ELEMENT current-user-privilege-set (privilege*)> <!ELEMENT current-user-privilege-set (privilege*)>
Clemm, Hopkins, Sedlar, Whitehead [Page 15]
<!ELEMENT privilege ANY> <!ELEMENT privilege ANY>
If the current user is granted a specific privilege, that If the current user is granted a specific privilege, that privilege
privilege must belong to the set of privileges that may be set must belong to the set of privileges that may be set on this
on this resource. Therefore, each element in the DAV:current- resource. Therefore, each element in the DAV:current-user-privilege-
user-privilege-set property MUST identify a non-abstract set property MUST identify a non-abstract privilege from the
privilege from the DAV:supported-privilege-set property. DAV:supported-privilege-set property.
5.3.1 Example: Retrieving the User's Current Set of Assigned 5.3.1 Example: Retrieving the UserĂs Current Set of Assigned Privileges
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 client requesting the DAV:current-user-privilege-set property from
from the resource with URL http://www.webdav.org/papers/. The the resource with URL http://www.webdav.org/papers/. The username of
username of the principal making the request is ˘khare÷, and the principal making the request is ˘khare", and Digest
Digest authentication is used in the request. The principal authentication is used in the request. The principal with username
with username ˘khare÷ has been granted the DAV:read privilege. ˘khare" has been granted the DAV:read privilege. Since the DAV:read
Since the DAV:read privilege contains the DAV:read-acl and privilege contains the DAV:read-acl and DAV:read-current-user-
DAV:read-current-user-privilege-set privileges (see Section privilege-set privileges (see Section 5.2.1), the principal with
5.2.1), the principal with username ˘khare÷ can read the ACL username ˘khare" can read the ACL property, and the DAV:current-user-
property, and the DAV:current-user-privilege-set property. privilege-set property. However, the DAV:all, DAV:read-acl,
However, the DAV:all, DAV:read-acl, DAV:write-acl and DAV:read- DAV:write-acl and DAV:read-current-user-privilege-set privileges are
current-user-privilege-set privileges are not listed in the not listed in the value of DAV:current-user-privilege-set, since (for
value of DAV:current-user-privilege-set, since (for this this example) they are abstract privileges. DAV:write is not listed
example) they are abstract privileges. DAV:write is not listed since the principal with username ˘khare" is not listed in an ACE
since the principal with username ˘khare÷ is not listed in an granting that principal write permission.
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="...",
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:current-user-privilege-set/> <D:current-user-privilege-set/>
</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" ?>
<D:multistatus xmlns:D="DAV:"> <D:multistatus xmlns:D="DAV:">
<D:response> <D:response>
Clemm, Hopkins, Sedlar, Whitehead [Page 16]
<D:href>http://www.webdav.org/papers/</D:href> <D:href>http://www.webdav.org/papers/</D:href>
<D:propstat> <D:propstat>
<D:status>HTTP/1.1 200 OK</D:status>
<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: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 control entries (ACEs), which define what principals are to get what
what privileges for this resource. privileges for this resource.
<!ELEMENT acl (ace*)> <!ELEMENT acl (ace*)>
Each DAV:ace element specifies the set of privileges to be Each DAV:ace element specifies the set of privileges to be either
either granted or denied to a single principal. If the DAV:acl granted or denied to a single principal. If the DAV:acl property is
property is empty, no principal is granted any privilege. empty, no principal is granted any privilege.
<!ELEMENT ace (principal, (grant|deny), protected?, <!ELEMENT ace (principal, (grant|deny), protected?, inherited?)>
inherited?)>
5.4.1 ACE Principal 5.4.1 ACE Principal
The DAV:principal element identifies the principal to which The DAV:principal element identifies the principal to which this ACE
this ACE applies. 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 The current user matches DAV:href only if that user is authenticated
authenticated as being (or being a member of) the principal as being (or being a member of) the principal identified by the URL
identified by the URL contained by that DAV:href. 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 The current user matches DAV:authenticated only if authenticated.
authenticated.
<!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.
Clemm, Hopkins, Sedlar, Whitehead [Page 17]
<!ELEMENT unauthenticated EMPTY> <!ELEMENT unauthenticated EMPTY>
DAV:all is the union of DAV:authenticated, and DAV:all is the union of DAV:authenticated, and DAV:unauthenticated.
DAV:unauthenticated. For a given request, the user matches For a given request, the user matches either DAV:authenticated, or
either DAV:authenticated, or DAV:unauthenticated, but not both DAV:unauthenticated, but not both (that is, DAV:authenticated and
(that is, DAV:authenticated and DAV:unauthenticated are DAV:unauthenticated are disjoint sets).
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 of a resource only if the value of the identified property
property of that resource contains at most one DAV:href XML of that resource contains at most one DAV:href XML element, the URI
element, the URI value of DAV:href identifies a principal, and value of DAV:href identifies a principal, and the current user is
the current user is authenticated as being (or being a member authenticated as being (or being a member of) that principal. For
of) that principal. For example, if the DAV:property element example, if the DAV:property element contained <DAV:owner/>, the
contained <DAV:owner/>, the current user would match the current user would match the DAV:property principal only if the
DAV:property principal only if the current user is current user is authenticated as matching the principal identified by
authenticated as matching the principal identified by the the DAV:owner property of the resource.
DAV:owner property of the resource.
<!ELEMENT property ANY> <!ELEMENT property ANY>
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 resource only if that resource is a principal object and the current
current user is authenticated as being that principal or a user is authenticated as being that principal or a member of that
member of that principal collection. principal collection.
<!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 Each DAV:grant or DAV:deny element specifies the set of privileges to
privileges to be either granted or denied to the specified be either granted or denied to the specified principal. A DAV:grant
principal. A DAV:grant or DAV:deny element of the DAV:acl of a or DAV:deny element of the DAV:acl of a resource MUST only contain
resource MUST only contain non-abstract elements specified in non-abstract elements specified in the DAV:supported-privilege-set of
the DAV:supported-privilege-set of that resource. that resource.
<!ELEMENT grant (privilege+)> <!ELEMENT grant (privilege+)>
<!ELEMENT deny (privilege+)> <!ELEMENT deny (privilege+)>
<!ELEMENT privilege ANY> <!ELEMENT privilege ANY>
5.4.3 ACE Protection 5.4.3 ACE Protection
If an ACE contains a DAV:protected element, an ACL request A server indicates an ACE is protected by including the DAV:protected
without that ACE MUST fail. element in the ACE. If the ACL of a resource contains an ACE with a
DAV:protected element, an attempt to remove that ACE 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 The presence of a DAV:inherited element indicates that this ACE is
is inherited from another resource that is identified by the inherited from another resource that is identified by the URL
URL contained in a DAV:href element. An inherited ACE cannot contained in a DAV:href element. An inherited ACE cannot be modified
be modified directly, but instead the ACL on the resource from directly, but instead the ACL on the resource from which it is
which it is inherited must be modified. inherited must be modified.
Clemm, Hopkins, Sedlar, Whitehead [Page 18] Note that ACE inheritance is not the same as ACL initialization. ACL
Note that ACE inheritance is not the same as ACL initialization defines the ACL that a newly created resource will use
initialization. ACL initialization defines the ACL that a (if not specified). ACE inheritance refers to an ACE that is
newly created resource will use (if not specified). ACE logically shared - where an update to the resource containing an ACE
inheritance refers to an ACE that is logically shared - where will affect the ACE of each resource that inherits that ACE. The
an update to the resource containing an ACE will affect the ACE method by which ACLs are initialized or by which ACEs are inherited
of each resource that inherits that ACE. The method by which is not defined by this document.
ACLs are initialized or by which ACEs are inherited is not
defined by this document.
<!ELEMENT inherited (href)> <!ELEMENT inherited (href)>
5.4.5 Example: Retrieving a Resource's Access Control List 5.4.5 Example: Retrieving a ResourceĂs Access Control List
Continuing the example from Sections 5.2.1 and 5.3.1, this Continuing the example from Sections 5.2.1 and 5.3.1, this example
example shows a client requesting the DAV:acl property from the shows a client requesting the DAV:acl property from the resource with
resource with URL http://www.webdav.org/papers/. There are two URL http://www.webdav.org/papers/. There are two ACEs defined in this
ACEs defined in this ACL: ACL:
ACE #1: The principal collection identified by URL ACE #1: The principal collection identified by URL
http://www.webdav.org/_acl/groups/maintainers/ (the group of http://www.webdav.org/_acl/groups/maintainers/ (the group of site
site maintainers) is granted DAV:write privilege. Since (for maintainers) is granted DAV:write privilege. Since (for this example)
this example) DAV:write contains the DAV:write-acl privilege DAV:write contains the DAV:write-acl privilege (see Section 5.2.1),
(see Section 5.2.1), this means the ˘maintainers÷ group can this means the ˘maintainers" group can also modify the access control
also modify the access control list. list.
ACE #2: All principals (DAV:all) are granted the DAV:read ACE #2: All principals (DAV:all) are granted the DAV:read privilege.
privilege. Since (for this example) DAV:read contains DAV:read- Since (for this example) DAV:read contains DAV:read-acl and DAV:read-
acl and DAV:read-current-user-privilege-set, this means all current-user-privilege-set, this means all users (including all
users (including all members of the ˘maintainers÷ group) can members of the ˘maintainers" group) can read the DAV:acl property and
read the DAV:acl property and the DAV:current-user-privilege- the DAV:current-user-privilege-set property.
set property.
>> 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:acl/> <D:acl/>
</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 19]
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:status>HTTP/1.1 200 OK</D:status>
<D:prop> <D:prop>
<D:acl> <D:acl>
<D:ace> <D:ace>
<D:principal> <D:principal>
<D:href> <D:href>
http://www.webdav.org/_acl/groups/maintainers/ http://www.webdav.org/_acl/groups/maintainers/
</D:href> </D:href>
</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:href> <D:all/> </D:href> <D:all/>
</D:principal> </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> </D:acl>
</D:prop> </D:prop>
<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:acl-semantics
This is a protected property that defines the ACL semantics. This is a protected property that defines the ACL semantics. These
These semantics define how multiple ACEs that match the current semantics define how multiple ACEs that match the current user are
user are combined, what are the constraints on how ACEs can be
ordered, and which principals must have an ACE. A client user
interface could use the value of this property to provide
feedback to a human operator concerning the impact of proposed
changes to an ACL. Alternately, a client can use this property
to help it determine, before submitting an ACL method
invocation, what ACL changes it needs to make to accomplish a
specific goal (or whether that goal is even achievable on this
server).
Since it is not practical to require all implementations to use Clemm, Hopkins, Sedlar, Whitehead [Page 23]
the same ACL semantics, the DAV:acl-semantics property is used combined, what are the constraints on how ACEs can be ordered, and
to identify the ACL semantics for a particular resource. The which principals must have an ACE. A client user interface could use
DAV:acl-semantics element is defined in Section 6. the value of this property to provide feedback to a human operator
concerning the impact of proposed changes to an ACL. Alternately, a
client can use this property to help it determine, before submitting
an ACL method invocation, what ACL changes it needs to make to
accomplish a specific goal (or whether that goal is even achievable
on this server).
Since it is not practical to require all implementations to use the
same ACL semantics, the DAV:acl-semantics property is used to
identify the ACL semantics for a particular resource. The DAV:acl-
semantics element is defined in Section 6.
Clemm, Hopkins, Sedlar, Whitehead [Page 20]
5.5.1 Example: Retrieving DAV:acl-semantics 5.5.1 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 semantics property. Digest authentication provides credentials for
for the principal operating the client. In this example, the the principal operating the client. In this example, the ACE
ACE combination semantics are DAV:first-match, described in combination semantics are DAV:first-match, described in Section
Section 6.1.1, the ACE ordering semantics are not specified 6.1.1, the ACE ordering semantics are not specified (some value other
(some value other than DAV:deny-before-grant, described in than DAV:deny-before-grant, described in Section 6.2.1), the
Section 6.2.1), the DAV:allowed-ace element states that only DAV:allowed-ace element states that only one ACE is permitted for
one ACE is permitted for each principal, and an ACE describing each principal, and an ACE describing the privileges granted the
the privileges granted the DAV:all principal must exist in DAV:all principal must exist in every ACL.
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
Depth: 0 Depth: 0
Authorization: Digest username="srcarter", Authorization: Digest username="srcarter",
realm="srcarter@webdav.org", nonce="...", realm="srcarter@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:acl-semantics/> <D:acl-semantics/>
</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:status>HTTP/1.1 200 OK</D:status>
<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>
<D:required-principal> <D:required-principal>
Clemm, Hopkins, Sedlar, Whitehead [Page 21]
<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:propstat> </D:propstat>
<D:response> <D:response>
</D:multistatus> </D:multistatus>
5.6 DAV:principal-collection-set 5.6 DAV:principal-collection-set
This protected property contains zero, one, or more URLs that This protected property contains zero, one, or more URLs that
identify a collection principal. It is expected that identify a collection principal. It is expected that implementations
implementations of this protocol will typically use a of this protocol will typically use a relatively small number of
relatively small number of locations in the URL namespace for locations in the URL namespace for principals, and collection
principal, and collection principals. In cases where this principals. In cases where this assumption holds, the DAV:principal-
assumption holds, the DAV:principal-collection-set property collection-set property will contain a small set of URLs identifying
will contain a small set of URLs identifying the top of a the top of a collection hierarchy containing multiple principals and
collection hierarchy containing multiple principals and collection principals. An access control protocol user agent could
collection principals. An access control protocol user agent use the contents of DAV:principal-collection-set to retrieve the
could use the contents of DAV:principal-collection-set to query DAV:displayname property (specified in Section 13.2 of [RFC2518]) of
the DAV:displayname property (specified in Section 13.2 of all principals on that server, thereby yielding human-readable names
[RFC2518]) of all principals on that server, thereby yielding for each principal that could be displayed in a user interface.
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 namespace, different resources on the same host MAY have different
different DAV:principal-collection-set values. The collections DAV:principal-collection-set values. The collections specified in the
specified in the DAV:principal-collection-set MAY be located on DAV:principal-collection-set MAY be located on different hosts from
different hosts from the resource. The URLs in DAV:principal- the resource. The URLs in DAV:principal-collection-set SHOULD be http
collection-set SHOULD be http or https scheme URLs. For or https scheme URLs. For security and scalability reasons, a server
security and scalability reasons, a server MAY report only a MAY report only a subset of the entire set of known collection
subset of the entire set of known collection principals, and
therefore clients should not assume they have retrieved an Clemm, Hopkins, Sedlar, Whitehead [Page 25]
exhaustive listing. Additionally, a server MAY elect to report principals, and therefore clients should not assume they have
none of the collection principals it knows about, in which case retrieved an exhaustive listing. Additionally, a server MAY elect to
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
DAV:principal-property-search REPORT (defined in Section 9.4).
Clients use the DAV:principal-property-search REPORT to populate
their user interface with a list of principals. Therefore, servers
that limit a client's ability to obtain principal information will
interfere with the client's ability to manipulate access control
lists, due to the difficulty of getting the URL of a principal for
use in an ACE.
5.6.1 Example: Retrieving DAV:principal-collection-set 5.6.1 Example: Retrieving DAV:principal-collection-set
In this example, the client requests the value of the In this example, the client requests the value of the DAV:principal-
DAV:principal-collection-set property on the collection collection-set property on the collection resource identified by URL
resource identified by URL http://www.webdav.org/papers/. The http://www.webdav.org/papers/. The property contains the two URLs,
property contains the two URLs,
http://www.webdav.org/_acl/users/ and http://www.webdav.org/_acl/users/ and
http://www.webdav.org/_acl/groups/, both wrapped in <DAV:href> http://www.webdav.org/_acl/groups/, both wrapped in <DAV:href> XML
XML elements. Digest authentication provides credentials for elements. Digest authentication provides credentials for the
the principal operating the client. principal operating the client.
The client might reasonably follow this request with two
separate PROPFIND requests to retrieve the DAV:displayname
Clemm, Hopkins, Sedlar, Whitehead [Page 22] The client might reasonably follow this request with two separate
property of the members of the two collections (/_acl/users/ PROPFIND requests to retrieve the DAV:displayname property of the
and /_acl_groups/). This information could be used when members of the two collections (/_acl/users/ and /_acl_groups/). This
displaying a user interface for creating access control information could be used when displaying a user interface for
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",
realm="yarong@webdav.org", nonce="...", realm="yarong@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:principal-collection-set/> <D:principal-collection-set/>
</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:status>HTTP/1.1 200 OK</D:status>
<D:prop> <D:prop>
<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:propstat> </D:propstat>
</D:response> </D:response>
</D:multistatus> </D:multistatus>
5.7 Example: PROPFIND to retrieve access control properties 5.7 Example: PROPFIND to retrieve access control properties
The following example shows how access control information can The following example shows how access control information can be
be retrieved by using the PROPFIND method to fetch the values retrieved by using the PROPFIND method to fetch the values of the
of the DAV:owner, DAV:supported-privilege-set, DAV:current- DAV:owner, DAV:supported-privilege-set, DAV:current-user-privilege-
user-privilege-set, and DAV:acl properties. set, and DAV:acl properties.
Clemm, Hopkins, Sedlar, Whitehead [Page 23]
>> Request << >> Request <<
PROPFIND /top/container/ HTTP/1.1 PROPFIND /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: xxx Content-Length: xxx
Depth: 0 Depth: 0
Authorization: Digest username="ejw", Authorization: Digest username="ejw",
realm="users@foo.org", nonce="...", realm="users@foo.org", nonce="...",
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: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>
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
<?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:status>HTTP/1.1 200 OK</D:status>
<D:prop> <D:prop>
<D:owner> <D:owner>
<D:href>http://www.foo.org/users/gclemm</D:href> <D:href>http://www.foo.org/users/gclemm</D:href> </D:owner>
</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>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>Read any object</D:description> <D:description xml:lang="en">Read any
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>Write any object</D:description> <D:description xml:lang="en">Write any
object</D:description>
<D:supported-privilege> <D:supported-privilege>
<D:privilege> <A:create/> </D:privilege> <D:privilege> <A:create/> </D:privilege>
<D:description>Create an object</D:description> <D:description xml:lang="en">Create an
object</D:description>
</D:supported-privilege> </D:supported-privilege>
<D:supported-privilege> <D:supported-privilege>
Clemm, Hopkins, Sedlar, Whitehead [Page 24]
<D:privilege> <A:update/> </D:privilege> <D:privilege> <A:update/> </D:privilege>
<D:description>Update an object</D:description> <D:description xml:lang="en">Update an
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>Delete an object</D:description> <D:description xml:lang="en">Delete an
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>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>
<D:privilege> <D:write-acl/> </D:privilege> <D:privilege> <D:write-acl/> </D:privilege>
<D:description>Write the ACL</D:description> <D:description xml:lang="en">Write the
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>
<D:acl> <D:acl>
<D:ace> <D:ace>
<D:principal> <D:principal>
skipping to change at line 1358 skipping to change at line 1442
<D:href>http://www.foo.org/groups/marketing/</D:href> <D:href>http://www.foo.org/groups/marketing/</D:href>
</D:principal> </D:principal>
<D:deny> <D:deny>
<D:privilege> <D:read/> </D:privilege> </D:deny> <D:privilege> <D:read/> </D:privilege> </D:deny>
</D:ace> </D:ace>
<D:ace> <D:ace>
<D:principal> <D:principal>
<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:privilege> <D:write-acl/> </D:privilege> </D:grant>
</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:href>http://www.foo.org/top/</D:href> </D:inherited>
</D:inherited>
Clemm, Hopkins, Sedlar, Whitehead [Page 25]
</D:ace> </D:acl> </D:ace> </D:acl>
</D:prop> </D:prop>
<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 The value of the DAV:owner property is a single DAV:href XML element
element containing the URL of the principal that owns this containing the URL of the principal that owns this resource.
resource.
The value of the DAV:supported-privilege-set property is a tree Clemm, Hopkins, Sedlar, Whitehead [Page 29]
of supported privileges: The value of the DAV:supported-privilege-set property is a tree of
supported privileges:
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 The DAV:current-user-privilege-set property contains two privileges,
privileges, DAV:read, and DAV:read-acl. This indicates that the DAV:read, and DAV:read-acl. This indicates that the current
current authenticated user only has the ability to read the authenticated user only has the ability to read the resource, and
resource, and read the DAV:acl property on the resource. 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, http://www.foo.org/users/esedlar is granted the DAV:read, DAV:write,
DAV:write, and DAV:read-acl privileges. 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 privilege. In this example, the principal URL identifies a group,
group, which is represented by a collection principal. 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, specifically the DAV:owner property. When evaluating this ACE, the
the value of the DAV:owner property is retrieved, and is value of the DAV:owner property is retrieved, and is examined to see
examined to see if it contains a DAV:href XML element. If so, if it contains a DAV:href XML element. If so, the URL within the
the URL within the DAV:href element is read, and identifies a DAV:href element is read, and identifies a principal. In this ACE,
principal. In this ACE, the owner is granted DAV:read-acl, and the owner is granted DAV:read-acl, and DAV:write-acl privileges.
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 http://www.foo.org/top/, the parent collection of this resource.
resource.
Clemm, Hopkins, Sedlar, Whitehead [Page 26]
6 ACL SEMANTICS 6 ACL SEMANTICS
The ACL semantics define how multiple ACEs that match the The ACL semantics define how multiple ACEs that match the current
current user are combined, what are the constraints on how ACEs user are combined, what are the constraints on how ACEs can be
can be ordered, and which principals must have an ACE. ordered, and which principals must have an ACE.
<!ELEMENT acl-semantics acl-sem*> <!ELEMENT acl-semantics (ace-combination?, ace-ordering?, allowed-
ace?, required-principal?)>
<!ELEMENT acl-sem (ace-combination, ace-ordering, allowed-ace, Clemm, Hopkins, Sedlar, Whitehead [Page 30]
required-principal*)>
6.1 ACE Combination 6.1 ACE Combination
The DAV:ace-combination element defines how privileges from The DAV:ace-combination element defines how privileges from multiple
multiple ACEs that match the current user will be combined to ACEs that match the current user will be combined to determine the
determine the access privileges for that user. Multiple ACEs access privileges for that user. Multiple ACEs may match the same
may match the same user because the same principal can appear user because the same principal can appear in multiple ACEs, because
in multiple ACEs, because multiple principals can identify the multiple principals can identify the same user, and because one
same user, and because one principal can be a member of another principal can be a member of another principal.
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 The ACEs are evaluated in the order in which they appear in the ACL.
ACL. If the first ACE that matches the current user does not If the first ACE that matches the current user does not grant all the
grant all the privileges needed for the request, the request privileges needed for the request, the request MUST fail.
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 The ACEs are evaluated in the order in which they appear in the ACL.
ACL. If an evaluated ACE denies a privilege needed for the If an evaluated ACE denies a privilege needed for the request, the
request, the request MUST fail. If all ACEs have been request MUST fail. If all ACEs have been evaluated without the user
evaluated without the user being granted all privileges needed being granted all privileges needed for the request, the request MUST
for the request, the request MUST fail. 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 All ACEs in the ACL are evaluated. An "individual ACE" is one whose
whose principal identifies the current user. A "group ACE" is principal identifies the current user. A "group ACE" is one whose
one whose principal is a collection that contains a principal principal is a collection that contains a principal that identifies
that identifies the current user. A privilege is granted if it the current user. A privilege is granted if it is granted by an
is granted by an individual ACE and not denied by an individual individual ACE and not denied by an individual ACE, or if it is
ACE, or if it is granted by a group ACE and not denied by an granted by a group ACE and not denied by an individual or group ACE.
individual or group ACE. A request MUST fail if any of its A request MUST fail if any of its needed privileges are not granted.
needed privileges are not granted.
Clemm, Hopkins, Sedlar, Whitehead [Page 27]
<!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 The DAV:ace-ordering element defines a constraint on how the ACEs can
ACEs can be ordered in the ACL. 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 This element indicates that all deny ACEs must precede all grant
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 The DAV:allowed-ace XML element specifies constraints on what kinds
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)*>
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 This element indicates that a principal can appear in only one ACE
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 This element indicates that ACEs with deny clauses are not allowed.
allowed.
<!ELEMENT grant-only EMPTY> <!ELEMENT grant-only EMPTY>
6.4 Required Principals 6.4 Required Principals
The required principal elements identify which principals must The required principal elements identify which principals must have
have an ACE defined in the ACL. an ACE defined in the ACL.
<!ELEMENT required-principal <!ELEMENT required-principal
(href | all | authenticated | unauthenticated | property | (all? | authenticated? | unauthenticated? | self? | href* |
self)> property*)>
For example, the following element requires that the ACL For example, the following element requires that the ACL contain a
contain a DAV:owner property ACE: DAV:owner property ACE:
<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>
Clemm, Hopkins, Sedlar, Whitehead [Page 28]
7 ACCESS CONTROL AND EXISTING METHODS 7 ACCESS CONTROL AND EXISTING METHODS
This section defines the impact of access control functionality This section defines the impact of access control functionality on
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 <<
skipping to change at line 1563 skipping to change at line 1639
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
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 When a resource is moved from one location to another due to a MOVE
MOVE request, the non-inherited ACEs in the DAV:acl property of request, the non-inherited and non-protected ACEs in the DAV:acl
the resource MUST NOT be modified, or the MOVE request fails. property of the resource MUST NOT be modified, or the MOVE request
fails. Handling of inherited and protected ACEs is intentionally
undefined to give server implementations flexibility in how they
implement ACE inheritance and protection.
7.3 COPY 7.3 COPY
The DAV:acl property on the resource at the destination of a The DAV:acl property on the resource at the destination of a COPY
COPY MUST be the same as if the resource was created by an MUST be the same as if the resource was created by an individual
individual resource creation request (e.g. MKCOL, PUT). resource creation request (e.g. MKCOL, PUT). Clients wishing to
preserve the DAV:acl property across a copy need to read the DAV:acl
property prior to the COPY, then perform an ACL operation on the new
resource at the destination to restore, insofar as this is possible,
the original access control list.
7.4 DELETE
The precise combination of privileges and resources necessary to
permit the DELETE method is intentionally left to the discretion of
each server implementation. It is envisioned that on some servers,
DELETE will require write permission on the collection containing the
resource to be deleted. On other servers, it might also require
write permission on the resource being deleted.
Clemm, Hopkins, Sedlar, Whitehead [Page 33]
7.5 LOCK
A lock on a resource ensures that only the lock owner can modify ACEs
that are not inherited and not protected (these are the only ACEs
that a client can modify with an ACL request). A lock does not
protect inherited or protected ACEs, since a client cannot modify
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 The ACL method modifies the access control list (which can be read
read via the DAV:acl property) of a resource. Specifically, via the DAV:acl property) of a resource. Specifically, the ACL
the ACL method only permits modification to ACEs that are not method only permits modification to ACEs that are not inherited, and
inherited, and are not protected. An ACL method invocation are not protected. An ACL method invocation modifies all non-
modifies all non-inherited and non-protected ACEs in a inherited and non-protected ACEs in a resourceĂs access control list
resource's access control list to exactly match the ACEs to exactly match the ACEs contained within in the DAV:acl XML element
contained within in the DAV:acl XML element (specified in (specified in Section 5.4) of the request body. An ACL request body
Section 5.4) of the request body. An ACL request body MUST MUST contain only one DAV:acl XML element. Unless the non-inherited
contain only one DAV:acl XML element. Unless the 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
Clemm, Hopkins, Sedlar, Whitehead [Page 29] request MUST fail.
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 DAV:acl property may only be a portion of the complete set of ACEs on
ACEs on that resource. If this is the case, an ACL request only that resource. If this is the case, an ACL request only modifies the
modifies the set of ACEs visible to the current user, and does set of ACEs visible to the current user, and does not affect any non-
not affect any non-visible ACE. visible ACE.
In order to avoid overwriting DAV:acl changes by another In order to avoid overwriting DAV:acl changes by another client, a
client, a client SHOULD acquire a WebDAV lock on the resource client SHOULD acquire a WebDAV lock on the resource before retrieving
before retrieving the DAV:acl property of a resource that it the DAV:acl property of a resource that it intends on updating.
intends on updating.
Implementation Note: Two common operations are to add or Implementation Note: Two common operations are to add or remove an
remove an ACE from an existing access control list. To ACE from an existing access control list. To accomplish this, a
accomplish this, a client uses the PROPFIND method to client uses the PROPFIND method to retrieve the value of the
retrieve the value of the DAV:acl property, then parses the DAV:acl property, then parses the returned access control list to
returned access control list to remove all inherited and remove all inherited and protected ACEs (these ACEs are tagged
protected ACEs (these ACEs are tagged with the DAV:inherited with the DAV:inherited and DAV:protected XML elements). In the
and DAV:protected XML elements). In the remaining set of non- remaining set of non-inherited, non-protected ACEs, the client can
inherited, non-protected ACEs, the client can add or remove add or remove one or more ACEs before submitting the final ACE set
one or more ACEs before submitting the final ACE set in the in the request body of the ACL method.
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, constraints on an ACL request. If the constraint is violated, a 403
a 403 (Forbidden) response MUST be returned and the indicated (Forbidden) response MUST be returned and the indicated XML element
XML element MUST be returned as the top level element in an XML MUST be returned as the top level element in an XML response body.
response body.
Clemm, Hopkins, Sedlar, Whitehead [Page 34]
<DAV:ace-conflict/>: A conflict exists between two or more ACEs <DAV:ace-conflict/>: A conflict exists between two or more ACEs
submitted in the ACL request. submitted in the ACL request.
<DAV:protected-ace-conflict/>: A conflict exists between an ACE <DAV:protected-ace-conflict/>: A conflict exists between an ACE in
in the ACL request and a protected ACE on the resource. For the ACL request and a protected ACE on the resource. For example, if
example, if the resource has a protected ACE granting DAV:write the resource has a protected ACE granting DAV:write to a given
to a given principal, then it would be a protected ACE conflict principal, then it would be a protected ACE conflict if the ACL
if the ACL request submitted an ACE denying DAV:write to the request submitted an ACE denying DAV:write to the same principal.
same principal.
<DAV:inherited-ace-conflict/>: A conflict exists between an ACE <DAV:inherited-ace-conflict/>: A conflict exists between an ACE in
in the ACL request and an inherited ACE on the resource. For the ACL request and an inherited ACE on the resource. For example, if
example, if the resource inherits an ACE from its parent the resource inherits an ACE from its parent collection granting
collection granting DAV:write to a given principal, then it DAV:write to a given principal, then it would be an inherited ACE
would be an inherited ACE conflict if the ACL request submitted conflict if the ACL request submitted an ACE denying DAV:write to the
an ACE denying DAV:write to the same principal. Note that same principal. Note that reporting of this error will be
reporting of this error will be implementation-dependent. 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.
Clemm, Hopkins, Sedlar, Whitehead [Page 30] <DAV:too-many-aces/>: An implementation MAY limit the number of ACEs
Implementations have the choice to either report this error, or in an ACL. However, ACL-compliant servers MUST support at least one
to allow the ACE to be set, and then let normal ACE evaluation ACE granting privileges to a single principal, and one ACE granting
rules determine whether the new ACE has any impact on the privileges to a collection principal.
privileges available to a specific principal.
<DAV:too-many-aces/>: An implementation MAY limit the number of <DAV:deny-before-grant/>: All non-inherited deny ACEs MUST precede
ACEs in an ACL. However, ACL-compliant servers MUST support at all non-inherited grant ACEs.
least one ACE granting privileges to a single principal, and
one ACE granting privileges to a collection principal.
<DAV:deny-before-grant/>: All non-inherited deny ACEs MUST <DAV:principal-only-one-ace/>: For implementations that have the
precede all non-inherited grant ACEs. DAV:principal-only-one-ace constraint (defined in Section 6.3.1),
this XML element indicates that fulfilling the ACL request would
result in multiple ACEs for one or more principals.
<DAV:principal-only-one-ace/>: For implementations that have <DAV:grant-only/>: For implementations that have the DAV:grant-only
the DAV:principal-only-one-ace constraint (defined in Section constraint (defined in Section 6.3.2), this XML element indicates the
6.3.1), this XML element indicates that fulfilling the ACL request contained one or more deny ACEs.
request would result in multiple ACEs for one or more
principals.
<DAV:grant-only/>: For implementations that have the DAV:grant- <DAV:no-abstract/>: The ACL request attempts to set an abstract
only constraint (defined in Section 6.3.2), this XML element privilege in an ACE (see Section 5.2).
indicates the request contained one or more deny ACEs.
<DAV:required-principal>: One or more required principals (see <DAV:supported-privilege/>: One or more of the privileges in the ACL
Section 6.4) would not be present in the access control list request is not supported by the resource.
after processing the ACL request. The DAV:required-principal
XML element MUST contain a list of the missing principal(s), <DAV:required-principal/>: One or more required principals (see
following the syntax specified in Section 6.4. Section 6.4) would not be present in the access control list after
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
ACL request does not identify a principal resource.
Clemm, Hopkins, Sedlar, Whitehead [Page 35]
<DAV:allowed-principal/>: One or more of the principal URLs in the
ACL request is not allowed in an ACE. 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., identified by the URL http://www.foo.org/users/esedlar (i.e., the
the user "esedlar") read and write privileges, grants the owner user "esedlar") read and write privileges, grants the owner of the
of the resource read-acl and write-acl privileges, and grants resource read-acl and write-acl privileges, and grants everyone read
everyone read privileges. 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="..."
<?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>
Clemm, Hopkins, Sedlar, Whitehead [Page 31]
<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:grant> <D:grant>
<D:privilege> <D:read/> </D:privilege> <D:privilege> <D:read/> </D:privilege>
<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>
skipping to change at line 1716 skipping to change at line 1822
<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>
</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:acl> </D:ace>
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 principal identified by the URL http://www.foo.org/users/esedlar
http://www.foo.org/users/esedlar (i.e., the user "esedlar") (i.e., the user "esedlar") write privileges. Prior to the request,
write privileges. Prior to the request, the DAV:acl property on the DAV:acl property on the resource contained a protected ACE (see
the resource contained a protected ACE (see Section 5.4.3) Section 5.4.3) granting DAV:owner the DAV:read and DAV:write
granting DAV:owner the DAV:read and DAV:write privileges. The privileges. The principal identified by URL
principal identified by URL http://www.foo.org/users/esedlar is http://www.foo.org/users/esedlar is the owner of the resource. The
the owner of the resource. The ACL method invocation fails ACL method invocation fails because the submitted ACE conflicts with
because the submitted ACE conflicts with the protected ACE, the protected ACE, thus violating the semantics of ACE protection.
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="..."
<?xml version="1.0" encoding="utf-8" ?> <?xml version="1.0" encoding="utf-8" ?>
Clemm, Hopkins, Sedlar, Whitehead [Page 32]
<D:acl xmlns:D="DAV:"> <D:acl xmlns:D="DAV:">
<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>
>> 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" ?>
<DAV:protected-ace-conflict/> <D:protected-ace-conflict xmlns:D="DAV:"/>
Clemm, Hopkins, Sedlar, Whitehead [Page 37]
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 In the following request, user "ejw", authenticated by information in
information in the Authorization header, tries to change the the Authorization header, tries to change the access control list on
access control list on the resource the resource http://www.foo.org/top/index.html. This resource has two
http://www.foo.org/top/index.html. This resource has two
inherited ACEs. 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. http://www.foo.org/privs/write-all and DAV:read-acl privileges. On
On this server, http://www.foo.org/privs/write-all is an this server, http://www.foo.org/privs/write-all is an aggregate
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 Inherited ACE #2 grants principal DAV:all the DAV:read privilege.
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 principal identified by the URL http://www.foo.org/users/ejw (i.e.,
(i.e., the user ˘ejw÷) DAV:write permission. This conflicts the user ˘ejw") DAV:write permission. This conflicts with inherited
with inherited ACE #1. Note that the decision to report an ACE #1. Note that the decision to report an inherited ACE conflict is
inherited ACE conflict is specific to this server specific to this server implementation. Another server implementation
implementation. Another server implementation could have could have allowed the new ACE to be set, and then used normal ACE
allowed the new ACE to be set, and then used normal ACE evaluation rules to determine whether the new ACE has any impact on
evaluation rules to determine whether the new ACE has any the privileges available to a principal.
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",
Clemm, Hopkins, Sedlar, Whitehead [Page 33]
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>
<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" ?>
<DAV:inherited-ace-conflict/>
Clemm, Hopkins, Sedlar, Whitehead [Page 38]
<D:inherited-ace-conflict xmlns:D="DAV:"/>
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 this example, user "ygoland", authenticated by information in the
in the Authorization header, tries to change the access control Authorization header, tries to change the access control list on the
list on the resource http://www.foo.org/diamond/engagement- resource http://www.foo.org/diamond/engagement-ring.gif. The ACL
ring.gif. The ACL request includes a single, syntactically and request includes a single, syntactically and semantically incorrect
semantically incorrect ACE, which attempts to grant the ACE, which attempts to grant the collection principal identified by
collection principal identified by the URL the URL http://www.foo.org/users/friends/ DAV:read privilege and deny
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 (i.e., the user "ygoland-so") DAV:read privilege. However, it is
http://www.foo.org/users/ygoland-so (i.e., the user "ygoland- illegal to have multiple principal elements, as well as both a grant
so") DAV:read privilege. However, it is illegal to have and deny element in the same ACE, so the request fails due to poor
multiple principal elements, as well as both a grant and deny
element in the same ACE, so the request fails due to poor
syntax. 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="...", uri="/diamond/engagement-ring.gif", response="...", opaque="..."
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 34]
<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 grant, and one to deny, the request would have been syntactically
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
A REPORT request is an extensible mechanism for obtaining The REPORT method (defined in Section 3.6 of [RFCxxxx]) provides an
information about a resource. Unlike a resource property, extensible mechanism for obtaining information about a resource.
which has a single value, the value of a report can depend on Unlike the PROPFIND method, which returns the value of one or more
additional information specified in the REPORT request body and named properties, the REPORT method can involve more complex
in the REPORT request headers. processing. REPORT is valuable in cases where the server has access
to all of the information needed to perform the complex request (such
Marshalling: as a query), and where it would require multiple requests for the
client to retrieve the information needed to perform the same
The body of a REPORT request specifies which report is being request.
requested, as well as any additional information that will be
used to customize the report.
The request MAY include a Depth header.
The response body for a successful request MUST contain the
requested report.
If a Depth request header is included, the response MUST be a
207 Multi-Status.
Postconditions:
The REPORT method MUST NOT change the content or dead
properties of any resource.
If a Depth request header is included, the request MUST be
applied separately to the collection itself and to all members
of the collection that satisfy the Depth value. The DAV:prop
element of a DAV:response for a given resource MUST contain the
requested report for that resource.
Clemm, Hopkins, Sedlar, Whitehead [Page 35]
9.2 DAV:acl-principal-props Report 9.2 DAV:acl-principal-props Report
The DAV:acl-principle-props report returns, for all principals The DAV:acl-principle-props report returns, for all principals in the
in the DAV:acl property that are identified by http(s) URLs, DAV:acl property that are identified by http(s) URLs, the value of
the value of the properties specified in the REPORT request the properties specified in the REPORT request body. In the case
body. In the case where a principal URL appears multiple times, where a principal URL appears multiple times, the DAV:acl-principal-
the DAV:acl-principal-props report MUST return the properties props report MUST return the properties for that principal only once.
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-props XML element.
<!ELEMENT acl-principal-props ANY> <!ELEMENT acl-principal-props 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.
prop: see RFC 2518, Section 12.11 prop: see RFC 2518, Section 12.11
The response body for a successful request MUST be a The response body for a successful request MUST be a DAV:multistatus
DAV:multistatus XML element (i.e., the response uses the same XML element (i.e., the response uses the same format as the response
format as the response for PROPFIND). 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 The response body for a successful DAV:acl-principal-props REPORT
REPORT request MUST contain a DAV:response element for each request MUST contain a DAV:response element for each principal
principal identified by an http(s) URL listed in a identified by an http(s) URL listed in a DAV:principal XML element of
DAV:principal XML element of an ACE within the DAV:acl property an ACE within the DAV:acl property of the resource identified by the
of the resource identified by the Request-URI. Request-URI.
9.2.1 Example: DAV:acl-principal-props Report 9.2.1 Example: DAV:acl-principal-props Report
Resource http;//www.webdav.org/index.html has an ACL with three Resource http://www.webdav.org/index.html has an ACL with three ACEs:
ACEs:
ACE #1: All principals (DAV:all) have DAV:read and DAV:read- ACE #1: All principals (DAV:all) have DAV:read and DAV:read-current-
current-user-privilege-set access. 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 http://www.webdav.org/people/gstein (the user ˘gstein") is granted
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 collection principal 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-props report
requesting the DAV:displayname property. It returns the value requesting the DAV:displayname property. It returns the value of
of DAV:displayname for resources DAV:displayname for resources http://www.webdav.org/people/gstein and
http://www.webdav.org/people/gstein and http://www.webdav.org/groups/authors/ , but not for DAV:all, since
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.
Clemm, Hopkins, Sedlar, Whitehead [Page 36]
>> 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-props xmlns:D="DAV:">
<D:prop> <D:prop>
skipping to change at line 2005 skipping to change at line 2082
<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 The DAV:principal-match REPORT is used to identify all members of a
of a collection that match the current user. In particular, if collection that match the current user. In particular, if the
the collection contains principals, the report can be used to collection contains principals, the report can be used to identify
identify all members of the collection that match the current all members of the collection that match the current user.
user. Alternatively, if the collection contains resources that Alternatively, if the collection contains resources that have a
have a property that identifies a principal (e.g. DAV:owner), property that identifies a principal (e.g. DAV:owner), then the
then the report can be used to identify all members of the report can be used to identify all members of the collection whose
collection whose property identifies a principal that matches property identifies a principal that matches the current user. For
the current user. For example, this report can return all of example, this report can return all of the resources in a collection
hierarchy that are owned by the current user.
Clemm, Hopkins, Sedlar, Whitehead [Page 37] The Depth header (defined in Section 9.2 of [RFC2518]), with value
the resources in a collection hierarchy that are owned by the "infinity", can be used with this report. In this case, the report
current user. operates on the collection in the Request-URI, as well as all child
collections, grandchild collections, etc.
Marshalling: Marshalling:
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 expectation is the value of the named property typically contains
contains an href element that contains the URI of a principal 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 The response body for a successful request MUST be a DAV:multistatus
DAV:multistatus XML element. 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 The response body for a successful DAV:principal-match REPORT request
request MUST contain a DAV:response element for each member of MUST contain a DAV:response element for each member of the collection
the collection that matches the current user. When the that matches the current user. When the DAV:principal-property
DAV:principal-property element is used, a match occurs if the element is used, a match occurs if the current user is the same as
current user is the same as the principal identified by the URI the principal identified by the URI found in the DAV:href element of
found in the DAV:href element of the property identified by the the property identified by the DAV:principal-property element. When
DAV:principal-property element. When the DAV:self element is the DAV:self element is used in a DAV:principal-match report issued
used in a DAV:principal-match report issued against a against a collection principal, it matches a child of the collection
collection principal, it matches a child of the collection
principal if that child (a principal resource) identifies the Clemm, Hopkins, Sedlar, Whitehead [Page 42]
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 identified by the URL http://www.webdav.org/doc/ that are owned by
by the current user. The current user (˘gclemm÷) is the current user. The current user (˘gclemm") is authenticated using
authenticated using Digest authentication. 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
Clemm, Hopkins, Sedlar, Whitehead [Page 38]
<?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 2104 skipping to change at line 2186
<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
The DAV:principal-property-search REPORT performs a substring search
on the character data value of specified properties. The server MUST
perform caseless matching of substrings. Only properties defined on
principal or collection principal resources are searched. For
implementation efficiency, servers do not typically support substring
searching on all properties. A client can discover the set of
searchable properties by using the principal-search-property-set
REPORT, defined in Section 9.5.
Implementation Note: The value of a WebDAV property is a sequence
of well-formed XML, and hence can include any character in the
Unicode/ISO-10646 standard, that is, most known characters in
human languages. Due to the idiosyncrasies of case mapping across
human languages, implementation of caseless matching is non-
trivial. Implementors are strongly encouraged to consult
[CaseMap], especially Section 2.3 ("Caseless Matching"), for
guidance when implementing their caseless matching algorithms.
Marshalling:
The DAV:principal-collection-set property of the resource identified
by the Request-URI specifies the scope of the DAV:principal-property-
search REPORT, as follows:
- All principal and collection principal resources identified in
DAV:principal-collection-set are searched
- 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
principal collections identified in the value of a DAV:principal-
collection-set property.
The request body MUST be a DAV:principal-property-search XML element
containing a search specification and an optional list of properties.
For every principal that matches the search specification, the
response will contain the value of the properties on that principal.
<!ELEMENT principal-property-search ((property-search+), prop?) >
The DAV:property-search element contains a prop element enumerating
the properties to be searched and a caseless-substring element,
containing the search string.
<!ELEMENT property-search (prop, caseless-substring) >
prop: see RFC 2518, Section 12.11
<!ELEMENT caseless-substring #PCDATA >
Clemm, Hopkins, Sedlar, Whitehead [Page 44]
Multiple property-search elements or multiple elements within a
DAV:prop element will be interpreted with a logical AND. An empty
DAV:caseless-substring element will match all properties specified in
its parent DAV:property-search element.
The response body for a successful request MUST be a DAV:multistatus
XML element.
multistatus: see RFC 2518, Section 12.9
The response body for a successful DAV:principal-property-search
REPORT request MUST contain a DAV:response element for each
principal whose property values satisfy the search specification
given in DAV:principal-property-search.
If DAV:prop is specified in the request body, the properties
specified in the DAV:prop element MUST be reported in the
DAV:response elements.
Errors:
If a request specifies a search of a property that is not
searchable, a 403 (Forbidden) response MUST be returned and the
response body MUST be a DAV:non-searchable-property element,
containing the unsearchable properties.
<!ELEMENT non-searchable-property (prop) >
9.4.1 Matching
There are several cases to consider when matching strings. The
easiest case is when a property value is "simple" and has only
character information item content (see [REC-XMLINFOSET]). For
example, the search string "julian" would match the DAV:displayname
property with value "Julian Reschke". Note that the on-the-wire
marshalling of DAV:displayname in this case is:
<D:displayname xmlns:D="DAV:">Julian Reschke</D:displayname>
The name of the property is encoded into the XML element information
item, and the character information item content of the property is
"Julian Reschke".
The more complicated case occurred when properties have mixed content
(that is, compound values consisting of multiple child element items,
other types of information items, and character information item
content). Consider the property http://www.webdav.org/props/aprop,
marshalled as:
Clemm, Hopkins, Sedlar, Whitehead [Page 45]
<W:aprop xmlns:W="http://www.webdav.org/props/">
{cdata 0}<W:elem1>{cdata 1}</W:elem1>
<W:elem2>{cdata 2}</W:elem2>{cdata 3}
</W:aprop>
In this case, substring matching is performed on each individual
contiguous sequence of character information items. In the example
above, a search string would be compared to the four following
strings:
{cdata 0}
{cdata 1}
{cdata 2}
{cdata 3}
That is, four individual caseless substring matches would be
performed, one each for {cdata 0}, {cdata 1}, {cdata 2}, and {cdata
3}.
9.4.2 Example: successful DAV:principal-property-search REPORT
In this example, the client requests the principal URLs of all users
whose DAV:displayname property contains the substring "doE" and whose
http://BigCorp.com/ns/title property (that is, their professional
title) contains "sales". In addition, the client requests five
properties to be returned with the matching principals:
In the DAV: namespace: displayname
In the http://www.BigCorp.com/ns/ namespace: department, phone,
office, salary
The response shows that two principal resources meet the search
specification, "John Doe" and "Zygdoebert Smith". The property
"salary" in namespace "http://www.BigCorp.com/ns/" is not returned,
since the principal making the request does not have sufficient
access permissions to read this property.
>> Request <<
REPORT /users/ HTTP/1.1
Host: www.BigCorp.com
Content-Type: text/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:principal-property-search xmlns:D="DAV:">
<D:property-search>
<D:prop>
Clemm, Hopkins, Sedlar, Whitehead [Page 46]
<D:displayname/>
</D:prop>
<D:caseless-substring>doE</D:caseless-substring>
</D:property-search>
<D:property-search>
<D:prop xmlns:B="http://www.BigCorp.com/ns/">
<B:title/>
</D:prop>
<D:caseless-substring>sales</D:caseless-substring>
</D:property-search>
<D:prop xmlns:B="http://www.BigCorp.com/ns/">
<D:displayname/>
<B:department/>
<B:phone/>
<B:office/>
<B:salary/>
</D:prop>
</D:principal-property-search>
>> Response <<
HTTP/1.1 207 Multi-Status
Content-Type: text/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:multistatus xmlns:D="DAV:" xmlns:B="http://BigCorp.com/ns/">
<D:response>
<D:href>http://www.BigCorp.com/users/jdoe</D:href>
<D:propstat>
<D:prop>
<D:displayname>John Doe</D:displayname>
<B:department>Widget Sales</B:department>
<B:phone>234-4567</B:phone>
<B:office>209</B:office>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
<D:propstat>
<D:prop>
<B:salary/>
</D:prop>
<D:status>HTTP/1.1 403 Forbidden</D:status>
</D:propstat>
</D:response>
<D:response>
<D:href>http://www.BigCorp.com/users/zsmith</D:href>
<D:propstat>
Clemm, Hopkins, Sedlar, Whitehead [Page 47]
<D:prop>
<D:displayname>Zygdoebert Smith</D:displayname>
<B:department>Gadget Sales</B:department>
<B:phone>234-7654</B:phone>
<B:office>114</B:office>
</D:prop>
<D:status>HTTP/1.1 200 OK</D:status>
</D:propstat>
<D:propstat>
<D:prop>
<B:salary/>
</D:prop>
<D:status>HTTP/1.1 403 Forbidden</D:status>
</D:propstat>
</D:response>
</D:multistatus>
9.4.3 Example: Unsuccessful DAV:principal-property-search REPORT
In this example, the client requests a search on the non-searchable
property "phone" in the namespace "http://www.BigCorp.com/ns/". The
response is a 403 (Forbidden), with a response body containing the
XML element DAV:non-searchable-property listing the non-searchable
property.
>> Request <<
REPORT /users/ HTTP/1.1
Host: www.BigCorp.com
Content-Type: text/xml; charset=utf-8
Content-Length: xxxx
<?xml version="1.0" encoding="utf-8" ?>
<D:principal-property-search xmlns:D="DAV:">
<D:property-search>
<D:prop xmlns:B="http://www.BigCorp.com/ns/">
<B:phone/>
</D:prop>
<D:caseless-substring>232</D:caseless-substring>
</D:property-search>
</D:principal-property-search>
>> Response <<
HTTP/1.1 403 FORBIDDEN
Content-Type: text/xml; charset=utf-8
Content-Length: xxxx
Clemm, Hopkins, Sedlar, Whitehead [Page 48]
<?xml version="1.0" encoding="utf-8" ?>
<D:non-searchable-property xmlns:D="DAV:">
<D:prop xmlns:B="http://www.BigCorp.com/ns/">
<B:phone/>
</D:prop>
</D:non-searchable-property>
9.5 DAV:principal-search-property-set REPORT
The DAV:principal-search-property-set REPORT identifies those
properties that may be searched using the DAV:principal-property-
search REPORT (defined in Section 9.4). The DAV:principal-collection-
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
all principal collections identified in the value of a DAV:principal-
collection-set property.
An access control protocol user agent could use the results of the
DAV:principal-search-property-set REPORT to present a query interface
to the user for retrieving principals.
Marshalling:
The request body MUST be an empty DAV:principal-search-property-set
XML element.
The response body MUST be a DAV:principal-search-property-set XML
element, containing a DAV:principal-search-property XML element for
each property that may be searched with the DAV:principal-property-
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
interactive access control client.
<!ELEMENT principal-search-property-set (principal-search-
property*) >
Each DAV:principal-search-property XML element contains exactly one
searchable property, and a description of the property.
Clemm, Hopkins, Sedlar, Whitehead [Page 49]
<!ELEMENT principal-search-property (prop, description) >
The DAV:prop element contains one principal property on which the
server is able to perform DAV:principal-property-search REPORTs.
prop: see RFC 2518, Section 12.11
The description element is a human-readable description of what
information this property represents. Servers MUST indicate the human
language of the description using the xml:lang attribute and SHOULD
consider the HTTP Accept-Language request header when selecting one
of multiple available languages.
<!ELEMENT description #PCDATA >
9.5.1 Example: DAV:principal-search-property-set REPORT
In this example, the client determines the set of searchable
principal properties by requesting the DAV:principal-search-property-
set REPORT on the root of the serverĂs principal URL collection set,
identified by http://www.BigCorp.com/users/.
>> Request <<
REPORT /users/ HTTP/1.1
Host: www.BigCorp.com
Content-Type: text/xml; charset="utf-8"
Content-Length: xxx
Accept-Language: en, de
Authorization: BASIC d2FubmFtYWs6cGFzc3dvcmQ=
<?xml version="1.0" encoding="utf-8" ?>
<D:principal-search-property-set xmlns:D="DAV:"/>
>> Response <<
HTTP/1.1 200 OK
Content-Type: text/xml; charset="utf-8"
Content-Length: xxx
<?xml version="1.0" encoding="utf-8" ?>
<D:principal-search-property-set xmlns:D="DAV:">
<D:principal-search-property>
<D:prop>
<D:displayname/>
</D:prop>
<D:description xml:lang="en">Full name</D:description>
</D:principal-search-property>
<D:principal-search-property>
<D:prop xmlns:B="http://BigCorp.com/ns/">
<B:title/>
Clemm, Hopkins, Sedlar, Whitehead [Page 50]
</D:prop>
<D:description xml:lang="en">Job title</D:description>
</D:principal-search-property>
</D:principal-search-property-set>
10 XML PROCESSING 10 XML PROCESSING
Implementations of this specification MUST support the XML Implementations of this specification MUST support the XML element
element ignore rule, as specified in Section 23.3.2 of ignore rule, as specified in Section 23.3.2 of [RFC2518], and the XML
[RFC2518], and the WebDAV XML Namespace interpretation Namespace Recommendation [REC-XML-NAMES].
convention, described in Section 23.4 of [RFC2518].
Note that use of the DAV namespace is reserved for XML elements and
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 In this specification, the only human-readable content can be found
found in the description XML element, found within the in the description XML element, found within the DAV:supported-
DAV:supported-privilege-set property. This element contains a privilege-set property. This element contains a human-readable
human-readable description of the capabilities controlled by a description of the capabilities controlled by a privilege. As a
privilege. As a result, the description element must be result, the description element must be capable of representing
capable of representing descriptions in multiple character descriptions in multiple character sets. Since the description
sets. Since the description element is found within a WebDAV element is found within a WebDAV property, it is represented on-the-
property, it is represented on-the-wire as XML [REC-XML], and wire as XML [REC-XML], and hence can leverage XML's language tagging
hence can leverage XML's language tagging and character set and character set encoding capabilities. Specifically, XML processors
encoding capabilities. Specifically, XML processors must, at must, at minimum, be able to read XML elements encoded using the UTF-
minimum, be able to read XML elements encoded using the UTF-8 8 [UTF-8] encoding of the ISO 10646 multilingual plane. XML examples
[UTF-8] encoding of the ISO 10646 multilingual plane. XML in this specification demonstrate use of the charset parameter of the
examples in this specification demonstrate use of the charset Content-Type header, as defined in [RFC3023], as well as the XML
parameter of the Content-Type header, as defined in [RFC3023], "encoding" attribute, which together provide charset identification
as well as the XML "encoding" attribute, which together provide information for MIME and XML processors. Furthermore, this
charset identification information for MIME and XML processors. specification requires server implementations to tag description
fields with the xml:lang attribute (see Section 2.12 of [REC-XML]),
which specifies the human language of the description. Additionally,
server implementations should take into account the value of the
Accept-Language HTTP header to determine which description string to
return.
For XML elements other than the description element, it is For XML elements other than the description element, it is expected
expected that implementations will treat the property names, that implementations will treat the property names, privilege names,
privilege names, and values as tokens, and convert these tokens and values as tokens, and convert these tokens into human-readable
text in the user's language and character set when displayed to a
person. Only a generic WebDAV property display utility would display
these values in their raw form to a human user.
Clemm, Hopkins, Sedlar, Whitehead [Page 39] For error reporting, we follow the convention of HTTP/1.1 status
into human-readable text in the user's language and character codes, including with each status code a short, English description
set when displayed to a person. Only a generic WebDAV property of the code (e.g., 200 (OK)). While the possibility exists that a
display utility would display these values in their raw form to poorly crafted user agent would display this message to a user,
a human user.
For error reporting, we follow the convention of HTTP/1.1 Clemm, Hopkins, Sedlar, Whitehead [Page 51]
status codes, including with each status code a short, English internationalized applications will ignore this message, and display
description of the code (e.g., 200 (OK)). While the an appropriate message in the user's language and character set.
possibility exists that a poorly crafted user agent would
display this message to a user, 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 Further internationalization considerations for this protocol are
are described in the WebDAV Distributed Authoring protocol described in the WebDAV Distributed Authoring protocol specification
specification [RFC2518]. [RFC2518].
12 SECURITY CONSIDERATIONS 12 SECURITY CONSIDERATIONS
Applications and users of this access control protocol should Applications and users of this access control protocol should be
be aware of several security considerations, detailed below. In aware of several security considerations, detailed below. In addition
addition to the discussion in this document, the security to the discussion in this document, the security considerations
considerations detailed in the HTTP/1.1 specification detailed in the HTTP/1.1 specification [RFC2616], the WebDAV
[RFC2616], the WebDAV Distributed Authoring Protocol Distributed Authoring Protocol specification [RFC2518], and the XML
specification [RFC2518], and the XML Media Types specification Media Types specification [RFC3023] should be considered in a
[RFC3023] should be considered in a security analysis of this security analysis of this protocol.
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 control lists, if a single user's authentication credentials are
are compromised, only those resources for which the user has compromised, only those resources for which the user has access
access permission can be read, modified, moved, or deleted. permission can be read, modified, moved, or deleted. With the
With the introduction of this access control protocol, if a introduction of this access control protocol, if a single compromised
single compromised user has the ability to change ACLs for a user has the ability to change ACLs for a broad range of other users
broad range of other users (e.g., a super-user), the number of (e.g., a super-user), the number of resources that could be altered
resources that could be altered by a single compromised user by a single compromised user increases. This risk can be mitigated by
increases. This risk can be mitigated by limiting the number of limiting the number of people who have write-acl privileges across a
people who have write-acl privileges across a broad range of broad range of resources.
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 The ability to read the access privileges (stored in the DAV:acl
DAV:acl property), or the privileges permitted the currently property), or the privileges permitted the currently authenticated
authenticated user (stored in the DAV:current-user-privilege- user (stored in the DAV:current-user-privilege-set property) on a
set property) on a resource may seem innocuous, since reading resource may seem innocuous, since reading an ACL cannot possibly
an ACL cannot possibly affect the resource's state. However, if affect the resource's state. However, if all resources have world-
all resources have world-readable ACLs, it is possible to readable ACLs, it is possible to perform an exhaustive search for
perform an exhaustive search for those resources that have those resources that have inadvertently left themselves in a
inadvertently left themselves in a vulnerable state, such as vulnerable state, such as being world-writeable. In particular, the
being world-writeable. In particular, the property retrieval property retrieval method PROPFIND, executed with Depth infinity on
an entire hierarchy, is a very efficient way to retrieve the DAV:acl
or DAV:current-user-privilege-set properties. Once found, this
vulnerability can be exploited by a denial of service attack in which
the open resource is repeatedly overwritten. Alternately, writeable
resources can be modified in undesirable ways.
Clemm, Hopkins, Sedlar, Whitehead [Page 40] To reduce this risk, read-acl privileges should not be granted to
method PROPFIND, executed with Depth infinity on an entire unauthenticated principals, and restrictions on read-acl and read-
hierarchy, is a very efficient way to retrieve the DAV:acl or
DAV:current-user-privilege-set properties. Once found, this
vulnerability can be exploited by a denial of service attack 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 Clemm, Hopkins, Sedlar, Whitehead [Page 52]
to unauthenticated principals, and restrictions on read-acl and current-user-privilege-set privileges for authenticated principals
cuprivset privileges for authenticated principals should be should be carefully analyzed when deploying this protocol. Access to
carefully analyzed when deploying this protocol. Access to the the current-user-privilege-set property will involve a tradeoff of
current-user-privilege-set property will involve a tradeoff of usability versus security. When the current-user-privilege-set is
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 of this protocol will need to evaluate this tradeoff in light of the
be exploited. Deployment of this protocol will need to evaluate requirements of the deployment environment.
this 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 specification intentionally does not address the issue of how to
to manage or discover the initial ACL that is placed upon a manage or discover the initial ACL that is placed upon a resource
resource when it is created. The only way to discover the when it is created. The only way to discover the initial ACL is to
initial ACL is to create a new resource, then retrieve the create a new resource, then retrieve the value of the DAV:acl
value of the DAV:acl property. This assumes the principal property. This assumes the principal creating the resource also has
creating the resource also has been granted the DAV:read-acl been granted the DAV:read-acl privilege.
privilege.
As a result, it is possible that a principal could create a As a result, it is possible that a principal could create a resource,
resource, and then discover that its ACL grants privileges that and then discover that its ACL grants privileges that are
are undesirable. Furthermore, this protocol makes it possible undesirable. Furthermore, this protocol makes it possible (though
(though unlikely) that the creating principal could be unable unlikely) that the creating principal could be unable to modify the
to modify the ACL, or even delete the resource. Even when the ACL, or even delete the resource. Even when the ACL can be modified,
ACL can be modified, there will be a short period of time when there will be a short period of time when the resource exists with
the resource exists with the initial ACL before its new ACL can the initial ACL before its new ACL can be set.
be set.
Several factors mitigate this risk. Human principals are often Several factors mitigate this risk. Human principals are often aware
aware of the default access permissions in their editing of the default access permissions in their editing environments and
environments and take this into account when writing take this into account when writing information. Furthermore, default
information. Furthermore, default privilege policies are privilege policies are usually very conservative, limiting the
usually very conservative, limiting the privileges granted by privileges granted by the initial ACL.
the initial ACL.
13 AUTHENTICATION 13 AUTHENTICATION
Authentication mechanisms defined in WebDAV also apply to this Authentication mechanisms defined for use with HTTP and WebDAV also
WebDAV Access Control Protocol, in particular the Basic and apply to this WebDAV Access Control Protocol, in particular the Basic
Digest authentication mechanisms defined in [RFC2617]. and Digest authentication mechanisms defined in [RFC2617].
Clemm, Hopkins, Sedlar, Whitehead [Page 41]
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] elements. All other IANA considerations mentioned in [RFC2518] also
also applicable to WebDAV ACL. 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 describes the position of the IETF concerning intellectual property
property claims made against this document. claims made against this document.
The IETF takes no position regarding the validity or scope of The IETF takes no position regarding the validity or scope of any
any intellectual property or other rights that might be claimed intellectual property or other rights that might be claimed to
to pertain to the implementation or use other technology pertain to the implementation or use other technology described in
described in this document or the extent to which any license this document or the extent to which any license under such rights
under such rights might or might not be available; neither does might or might not be available; neither does it represent that it
it represent that it has made any effort to identify any such has made any effort to identify any such rights. Information on the
rights. Information on the IETF's procedures with respect to IETF's procedures with respect to rights in standards-track and
rights in standards-track and standards-related documentation standards-related documentation can be found in BCP-11. Copies of
can be found in BCP-11. Copies of claims of rights made claims of rights made available for publication and any assurances of
available for publication and any assurances of licenses to be licenses to be made available, or the result of an attempt made to
made available, or the result of an attempt made to obtain a obtain a general license or permission for the use of such
general license or permission for the use of such proprietary proprietary rights by implementers or users of this specification can
rights by implementers or users of this specification can be be obtained from the IETF Secretariat.
obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention The IETF invites any interested party to bring to its attention any
any copyrights, patents or patent applications, or other copyrights, patents or patent applications, or other proprietary
proprietary rights that may cover technology that may be rights that may cover technology that may be required to practice
required to practice this standard. Please address the this standard. Please address the information to the IETF Executive
information to the IETF Executive Director. Director.
16 ACKNOWLEDGEMENTS 16 ACKNOWLEDGEMENTS
This protocol is the collaborative product of the WebDAV ACL This protocol is the collaborative product of the WebDAV ACL design
design team: Bernard Chester, Geoff Clemm, Anne Hopkins, Barry team: Bernard Chester, Geoff Clemm, Anne Hopkins, Barry Lind, Sean
Lind, Sean Lyndersay, Eric Sedlar, Greg Stein, and Jim Lyndersay, Eric Sedlar, Greg Stein, and Jim Whitehead. The authors
Whitehead. The authors are grateful for the detailed review and are grateful for the detailed review and comments provided by Jim
comments provided by Jim Amsden, Gino Basso, Murthy Amsden, Gino Basso, Murthy Chintalapati, Dennis Hamilton, Laurie
Chintalapati, Dennis Hamilton, Laurie Harper, Ron Jacobs, Chris Harper, Ron Jacobs, Chris Knight, Remy Maucherat, Larry Masinter,
Knight, Remy Maucherat, Larry Masinter, Yaron Goland, Lisa Yaron Goland, Lisa Dusseault, Joe Orton, Stefan Eissing, Julian
Dusseault, and Joe Orton. Prior work on WebDAV access control Reschke, Keith Wannamaker, Tim Ellison, and Dylan Barrell. We thank
protocols has been performed by Yaron Goland, Paul Leach, Lisa Keith Wannamaker for the initial text of the principal property
Dusseault, Howard Palmer, and Jon Radoff. We would like to search sections. Prior work on WebDAV access control protocols has
acknowledge the foundation laid for us by the authors of the been performed by Yaron Goland, Paul Leach, Lisa Dusseault, Howard
WebDAV and HTTP protocols upon which this protocol is layered, Palmer, and Jon Radoff. We would like to acknowledge the foundation
and the invaluable feedback from the WebDAV working group. laid for us by the authors of the DeltaV, WebDAV and HTTP protocols
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 42]
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, Harvard, 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 Markup Language (XML)." World Wide Web Consortium Recommendation REC-
Recommendation REC-xml-19980210. http://www.w3.org/TR/REC-xml- xml.http://www.w3.org/TR/REC-xml
19980210.
[RFC2616] R. Fielding, J. Gettys, J. C. Mogul, H. Frystyk, L. [REC-XML-NAMES] T. Bray, D. Hollander, A. Layman, ˘Name Spaces in
Masinter, P. Leach, and T. Berners-Lee, "Hypertext Transfer XML" World Wide Web Consortium Recommendation REC-xml-names.
Protocol -- HTTP/1.1." RFC 2616. U.C. Irvine, Compaq, Xerox, http://www.w3.org/TR/REC-xml-names/
Microsoft, MIT/LCS, June, 1999.
[RFC2617] J. Franks, P. Hallam-Baker, J. Hostetler, S. [RFCxxxx] G. Clemm, J. Amsden, T. Ellison, C. Kaler, J. Whitehead,
Lawrence, P. Leach, A. Luotonen, L. Stewart, "HTTP "Versioning Extensions to WebDAV." RFC xxxx. Rational, IBM,
Authentication: Basic and Digest Access Authentication." RFC Microsoft, U.C. Santa Cruz, 2001.
2617. Northwestern University, Verisign, AbiSource, Agranat,
Microsoft, Netscape, Open Market, June, 1999.
[RFC2518] Y. Goland, E. Whitehead, A. Faizi, S. R. Carter, D. [REC-XML-INFOSET] J. Cowan, R. Tobin, "XML Information Set." World
Jensen, "HTTP Extensions for Distributed Authoring -- WEBDAV." Wide Web Consortium Recommendation REC-xml-infoset.
RFC 2518. Microsoft, U.C. Irvine, Netscape, Novell, February, http://www.w3.org/TR/xml-infoset/
[RFC2616] R. Fielding, J. Gettys, J. C. Mogul, H. Frystyk, L.
Masinter, P. Leach, and T. Berners-Lee, "Hypertext Transfer Protocol
-- HTTP/1.1." RFC 2616. U.C. Irvine, Compaq, Xerox, Microsoft,
MIT/LCS, June, 1999.
[RFC2617] J. Franks, P. Hallam-Baker, J. Hostetler, S. Lawrence, P.
Leach, A. Luotonen, L. Stewart, "HTTP Authentication: Basic and
Digest Access Authentication." RFC 2617. Northwestern University,
Verisign, AbiSource, Agranat, Microsoft, Netscape, Open Market, June,
1999. 1999.
[RFC2518] Y. Goland, E. Whitehead, A. Faizi, S. R. Carter, D. Jensen,
"HTTP Extensions for Distributed Authoring -- WEBDAV." RFC 2518.
Microsoft, U.C. Irvine, Netscape, Novell, 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, scheme." RFC 2368. Internet Mail Consortium, Xerox, Netscape, July,
July, 1998. 1998.
[RFC2255] T. Howes, M. Smith, "The LDAP URL Format." RFC 2255. [RFC3023] M. Murata, S. St.Laurent, D. Kohn, "XML Media Types." RFC
Netscape, December, 1997. 3023. IBM Tokyo Research Laboratory, simonstl.com, Skymoon Ventures,
January, 2001.
[RFC3023] M. Murata, S. St.Laurent, D. Kohn, "XML Media Types." [UTF-8] F. Yergeau, "UTF-8, a transformation format of Unicode and
RFC 3023. IBM Tokyo Research Laboratory, simonstl.com, Skymoon ISO 10646." RFC 2279. Alis Technologies. January, 1998.
Ventures, January, 2001.
[UTF-8] F. Yergeau, "UTF-8, a transformation format of Unicode Clemm, Hopkins, Sedlar, Whitehead [Page 55]
and ISO 10646." RFC 2279. Alis Technologies. January, 1998.
17.2 Informational References 17.2 Informational References
[RFC2026] S.Bradner, "The Internet Standards Process ű Revision [RFC2026] S.Bradner, "The Internet Standards Process ű Revision 3."
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.
Netscape, December, 1997.
[RFC2251] M. Wahl, T. Howes, S. Kille, "Lightweight Directory Access
Protocol (v3)." RFC 2251. Critical Angle, Netscape, Isode, December,
1997.
[CaseMap] M. Davis, "Case Mappings", Unicode Technical Report #21,
<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
Clemm, Hopkins, Sedlar, Whitehead [Page 43]
Anne Hopkins Anne Hopkins
Microsoft Corporation Microsoft Corporation
One Microsoft Way One Microsoft Way
Redmond, WA 98052 Redmond, WA 98052
Email: annehop@microsoft.com Email: annehop@microsoft.com
Eric Sedlar Eric Sedlar
Oracle Corporation Oracle Corporation
500 Oracle Parkway 500 Oracle Parkway
Redwood Shores, CA 94065 Redwood Shores, CA 94065
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]
19 APPENDICIES 19 APPENDICIES
19.1 XML Document Type Definition 19.1 WebDAV XML Document Type Definition Addendum
All XML elements defined in this Document Type Definition (DTD)
belong to the DAV namespace. This DTD should be viewed as an 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 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 is-principal (#PCDATA)> <!ELEMENT principalEMPTY>
<!ELEMENT alternate-URL (href*)> <!ELEMENT alternate-URI-set (href*)>
<!ELEMENT principal-URL (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*)>
Clemm, Hopkins, Sedlar, Whitehead [Page 44]
<!ELEMENT privilege ANY> <!ELEMENT privilege ANY>
<!ELEMENT abstract EMPTY> <!ELEMENT abstract EMPTY>
<!ELEMENT description #PCDATA> <!ELEMENT description #PCDATA>
<!ELEMENT privilege ANY> <!ELEMENT privilege ANY>
<!-- 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*)>
<!ELEMENT ace (principal, (grant|deny), protected?, <!ELEMENT ace (principal, (grant|deny), protected?, inherited?)>
inherited?)>
<!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>
skipping to change at line 2444 skipping to change at line 2915
<!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 5.6) -->
<!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 acl-sem*> <!ELEMENT acl-semantics (ace-combination?, ace-ordering?, allowed-
<!ELEMENT acl-sem (ace-combination, ace-ordering, allowed-ace, ace?, required-principal?)>
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)>
<!ELEMENT first-match EMPTY> <!ELEMENT first-match EMPTY>
<!ELEMENT all-grant-before-any-deny EMPTY> <!ELEMENT all-grant-before-any-deny EMPTY>
Clemm, Hopkins, Sedlar, Whitehead [Page 45]
<!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)*>
<!ELEMENT principal-only-one-ace EMPTY> <!ELEMENT principal-only-one-ace EMPTY>
<!ELEMENT grant-only EMPTY> <!ELEMENT grant-only EMPTY>
<!ELEMENT required-principal <!ELEMENT required-principal
(href | all | authenticated | unauthenticated | property |
self)> Clemm, Hopkins, Sedlar, Whitehead [Page 58]
(all? | authenticated? | unauthenticated? | self? | href*
|property*)>
<!-- ACL method preconditions (Section 8.1.1) --> <!-- ACL method preconditions (Section 8.1.1) -->
<!ELEMENT ace-conflict EMPTY> <!ELEMENT ace-conflict EMPTY>
<!ELEMENT protected-ace-conflict EMPTY> <!ELEMENT protected-ace-conflict EMPTY>
<!ELEMENT inherited-ace-conflict EMPTY> <!ELEMENT inherited-ace-conflict EMPTY>
<!ELEMENT too-many-aces EMPTY> <!ELEMENT too-many-aces EMPTY>
<!-- REPORT Method --> <!-- REPORTs (Section 9) -->
<!ELEMENT acl-principal-props ANY> <!ELEMENT acl-principal-props 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 expectation is the value of the named property typically contains
contains an href element that contains the URI of a principal an href element that contains the URI of a principal
<!ELEMENT self EMPTY> <!ELEMENT self EMPTY>
20 NOTE TO RFC EDITOR <!ELEMENT principal-property-search ((property-search+), prop?) >
<!ELEMENT property-search (prop, caseless-substring) >
<!ELEMENT caseless-substring #PCDATA >
<!ELEMENT non-searchable-property (prop) >
*** This section (Section 20) MUST be removed before <!ELEMENT principal-search-property-set (principal-search-
publication as an RFC *** property*) >
<!ELEMENT principal-search-property (prop, description) >
Section 9.1 defines the REPORT method. The REPORT method is 20 NOTE TO RFC EDITOR
also defined in draft-ietf-deltav-versioning-15, in Section
3.6, using identical text. This was done to avoid making this
specification dependent on draft-ietf-deltav-versioning.
If draft-ietf-deltav-versioning is published as an RFC before As of the writing of this specification, the DeltaV protocol,
this specification, Section 9.1 MUST be removed. 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 46] Clemm, Hopkins, Sedlar, Whitehead [Page 59]
 End of changes. 

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