draft-ietf-imapext-2086upd-01.txt   draft-ietf-imapext-2086upd-02.txt 
IMAPEXT Working Group A. Melnikov IMAPEXT Working Group A. Melnikov
Internet Draft Editor Internet Draft Editor
Document: draft-ietf-imapext-2086upd-01.txt November 2004 Document: draft-ietf-imapext-2086upd-02.txt December 2004
Updates: 2086, <<3501?>> Updates: <<3501?>>
Expires: May 2005 Obsoletes: 2086
Expires: June 2005
IMAP4 ACL extension - IMAP4 ACL extension
updated list of rights
Status of this Memo Status of this Memo
By submitting this Internet-Draft, I certify that any applicable By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been disclosed, or patent or other IPR claims of which I am aware have been disclosed, or
will be disclosed, and any of which I become aware will be disclosed, will be disclosed, and any of which I become aware will be disclosed,
in accordance with RFC 3668. in accordance with RFC 3668.
Internet Drafts are working documents of the Internet Engineering Internet Drafts are working documents of the Internet Engineering
Task Force (IETF), its Areas, and its Working Groups. Note that Task Force (IETF), its Areas, and its Working Groups. Note that
skipping to change at line 42 skipping to change at line 42
Directories on ds.internic.net, nic.nordu.net, ftp.isi.edu, or Directories on ds.internic.net, nic.nordu.net, ftp.isi.edu, or
munnari.oz.au. munnari.oz.au.
A revised version of this draft document will be submitted to the RFC A revised version of this draft document will be submitted to the RFC
editor as a Proposed Standard for the Internet Community. Discussion editor as a Proposed Standard for the Internet Community. Discussion
and suggestions for improvement are requested. Distribution of this and suggestions for improvement are requested. Distribution of this
draft is unlimited. draft is unlimited.
Abstract Abstract
The ACL (Access Control List) extension [RFC2086] of the Internet Message The ACL (Access Control List) extension (RFC 2086) of the Internet
Access Protocol [IMAP4] permits mailbox access control lists to be Message Access Protocol (IMAP4rev1) permits mailbox access control
manipulated through the IMAP protocol. lists to be manipulated through the IMAP protocol.
This document updates the list of rights defined in RFC 2086. It This document is a revision of the RFC 2086. It defines several new
also clarifies which rights are required for different IMAP commands. access control rights and clarifies which rights are required for
different IMAP commands.
1. Conventions Used in this Document 1. Conventions Used in this Document
In examples, "C:" and "S:" indicate lines sent by the client and In examples, "C:" and "S:" indicate lines sent by the client and
server respectively. server respectively.
In all examples "/" character is used as hierarchy separator. In all examples "/" character is used as hierarchy separator.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [KEYWORDS]. document are to be interpreted as described in RFC 2119 [KEYWORDS].
2. Introduction and Overview 2. Introduction and Overview
The ACL (Access Control List) extension of the Internet Message Access The ACL (Access Control List) extension of the Internet Message Access
Protocol [IMAP4] permits mailbox access control lists to be retrieved Protocol [IMAP4] permits mailbox access control lists to be retrieved
and manipulated through the IMAP protocol. and manipulated through the IMAP protocol.
This document updates Section 3 of the RFC 2086. It also clarifies This document is a revision of the RFC 2086. It tries to clarify
different aspects of the RFC 2086, in particular use of UTF-8 [UTF-8] in different ambiguities in the RFC 2086, in particular use of UTF-8
identifiers, which rights are required for different IMAP4 commands; [UTF-8] in identifiers, which rights are required for different IMAP4
how READ-WRITE/READ-ONLY response codes are related to ACL. commands; how READ-WRITE/READ-ONLY response codes are related to ACL.
3. Access Control 3. Access Control
This section replaces Section 3 of the RFC 2086.
The ACL extension is present in any IMAP4 implementation which The ACL extension is present in any IMAP4 implementation which
returns "ACL" as one of the supported capabilities to the CAPABILITY returns "ACL" as one of the supported capabilities to the CAPABILITY
command. command.
A server implementation conformant to this document MUST also return A server implementation conformant to this document MUST also return
rights (see below) not defined in RFC 2086 in the "RIGHTS=" capability rights (see below) not defined in RFC 2086 in the "RIGHTS=" capability
response. response.
An access control list is a set of <identifier,rights> pairs. An access control list is a set of <identifier,rights> pairs.
An ACL applies to a mailbox. An ACL applies to a mailbox name.
Identifier is a UTF-8 [UTF-8] string. The identifier "anyone" is reserved Identifier is a UTF-8 [UTF-8] string. The identifier "anyone" is reserved
to refer to the universal identity (all authentications, including to refer to the universal identity (all authentications, including
anonymous). All user name strings accepted by the LOGIN or anonymous). All user name strings accepted by the LOGIN or
AUTHENTICATE commands to authenticate to the IMAP server are reserved AUTHENTICATE commands to authenticate to the IMAP server are reserved
as identifiers for the corresponding users. Identifiers starting with as identifiers for the corresponding users. Identifiers starting with
a dash ("-") are reserved for "negative rights", described below. a dash ("-") are reserved for "negative rights", described below.
All other identifier strings are interpreted in an implementation- All other identifier strings are interpreted in an implementation-
defined manner. defined manner.
Rights is a string listing a (possibly empty) set of alphanumeric Rights is a string listing a (possibly empty) set of alphanumeric
characters, each character listing a set of operations which is being characters, each character listing a set of operations which is being
controlled. Letters are reserved for ''standard'' rights, listed controlled. Lowercase letters are reserved for "standard" rights,
below. (Note that a right represented by a letter is case-sensitive, listed in section 3.1. (Note that for compatibility with deployed clients
e.g. the "r" right is not the same as the "R" right. <<problem?>>) The set of and servers uppercase rights are not allowed). The set of
standard rights may only be extended by a standards-track document. standard rights may only be extended by a standards-track document.
Digits are reserved for implementation or site defined rights. The Digits are reserved for implementation or site defined rights.
currently defined standard rights are (note, that the list below doesn't
list all commands that use a particular right):
l - lookup (mailbox is visible to LIST/LSUB commands, SUBSCRIBE mailbox)
r - read (SELECT the mailbox, perform STATUS)
s - keep seen/unseen information across sessions (set or clear \SEEN flag
via STORE, APPEND or COPY)
w - write (set or clear flags other than \SEEN and \DELETED via STORE,
APPEND or COPY)
i - insert (perform APPEND, COPY into mailbox)
p - post (send mail to submission address for mailbox,
not enforced by IMAP4 itself.
c - create mailboxes (CREATE new sub-mailboxes in any
implementation-defined hierarchy, parent mailbox for the new
mailbox name in RENAME)
x - delete mailbox (DELETE mailbox, old mailbox name in RENAME)
t - delete messages (set or clear \DELETED flag via STORE, set \DELETED flag
during APPEND/COPY)
e - perform EXPUNGE and expunge as a part of CLOSE
d - This right is defined for backward compatibility with ACL
extension (RFC 2086). See below for details on how servers
should interpret it in commands that alter ACLs and when it
should be included in responses that return ACLs or lists of
rights.
a - administer (perform SETACL/DELETEACL/GETACL)
m - write private annotations [ANNOTATE]
n - write shared annotations [ANNOTATE]
An implementation may tie rights together or may force rights to An implementation may tie rights together or may force rights to
always or never be granted to particular identifiers. For example, always or never be granted to particular identifiers. For example,
in an implementation that uses unix mode bits, the rights "swite" are in an implementation that uses unix mode bits, the rights "swite" are
tied, the "a" right is always granted to the owner of a mailbox and tied, the "a" right is always granted to the owner of a mailbox and
is never granted to another user. If rights are tied in an is never granted to another user. If rights are tied in an
implementation, the implementation must be conservative in granting implementation, the implementation must be conservative in granting
rights in response to SETACL commands--unless all rights in a tied rights in response to SETACL commands--unless all rights in a tied
set are specified, none of that set should be included in the ACL set are specified, none of that set should be included in the ACL
entry for that identifier. A client may discover the set of rights entry for that identifier. A client may discover the set of rights
which may be granted to a given identifier in the ACL for a given which may be granted to a given identifier in the ACL for a given
mailbox by using the LISTRIGHTS command. mailbox name by using the LISTRIGHTS command.
If a client includes the "d" right in a rights list, then it MUST be
treated as if the client had included the "x", "e" and "t" rights.
(It is not an error for a client to specify both "d" and one or more
of the "x", "e" and "t" rights, but the effect is no different than
if just the "d" right or all of the "x", "e" and "t" had been specified).
When all three of the "x", "e", and "t" rights are set in a list of
rights, the server MUST also include the "d" right when returning
the list in a MYRIGHTS response/response code or ACL response.
If the "x", "e", and "t" rights are not tied together, the "d" right
MUST NOT be returned in a LISTRIGHTS response.
It is possible for multiple identifiers in an access control list to It is possible for multiple identifiers in an access control list to
apply to a given user (or other authentication identity). For apply to a given user (or other authentication identity). For
example, an ACL m example, an ACL may include rights to be granted to the identifier
ay include rights to be granted to the identifier
matching the user, one or more implementation-defined identifiers matching the user, one or more implementation-defined identifiers
matching groups which include the user, and/or the identifier matching groups which include the user, and/or the identifier
"anyone". How these rights are combined to determine the user's "anyone". How these rights are combined to determine the user's
access is implementation-defined. An implementation may choose, for access is implementation-defined. An implementation may choose, for
example, to use the union of the rights granted to the applicable example, to use the union of the rights granted to the applicable
identifiers. An implementation may instead choose, for example, to identifiers. An implementation may instead choose, for example, to
only use those rights granted to the most specific identifier present only use those rights granted to the most specific identifier present
in the ACL. A client may determine the set of rights granted to the in the ACL. A client may determine the set of rights granted to the
logged-in user for a given mailbox by using the MYRIGHTS command. logged-in user for a given mailbox name by using the MYRIGHTS command.
When an identifier in an ACL starts with a dash ("-"), that indicates When an identifier in an ACL starts with a dash ("-"), that indicates
that associated rights are to be removed from the identifier that is that associated rights are to be removed from the identifier that is
prefixed by the dash. This is referred to as a "negative right". prefixed by the dash. This is referred to as a "negative right".
This differs from DELETEACL in that a negative right is added to the This differs from DELETEACL in that a negative right is added to the
ACL, and is a part of the calculation of the rights. ACL, and is a part of the calculation of the rights.
Let's assume that an identifier "fred" refers to a user with login "fred". Let's assume that an identifier "fred" refers to a user with login "fred".
If the identifier "-fred" is granted the "w" right, If the identifier "-fred" is granted the "w" right,
that indicates that the "w" right is to be removed from users matching that indicates that the "w" right is to be removed from users matching
the identifier "fred", even though the user "fred" might have the identifier "fred", even though the user "fred" might have
the "w" right as a consequence of some other identifier in the ACL. the "w" right as a consequence of some other identifier in the ACL.
A DELETEACL of "fred" simply deletes the identifier "fred" A DELETEACL of "fred" simply deletes the identifier "fred"
from the ACL; it does not affect any rights that the user "fred" from the ACL; it does not affect any rights that the user "fred"
may get from another entry in the ACL. may get from another entry in the ACL.
Server implementations are not required to support "negative right" Server implementations are not required to support "negative right"
identifiers. identifiers.
4. Rights required to perform different IMAP4rev1 commands 3.1. Standard rights
The currently defined standard rights are (note, that the list below
doesn't list all commands that use a particular right):
l - lookup (mailbox is visible to LIST/LSUB commands, SUBSCRIBE mailbox)
r - read (SELECT the mailbox, perform STATUS)
s - keep seen/unseen information across sessions (set or clear \SEEN flag
via STORE, APPEND or COPY)
w - write (set or clear flags other than \SEEN and \DELETED via STORE,
APPEND or COPY)
i - insert (perform APPEND, COPY into mailbox)
p - post (send mail to submission address for mailbox,
not enforced by IMAP4 itself)
k - create mailboxes (CREATE new sub-mailboxes in any
implementation-defined hierarchy, parent mailbox for the new
mailbox name in RENAME)
x - delete mailbox (DELETE mailbox, old mailbox name in RENAME)
t - delete messages (set or clear \DELETED flag via STORE, set \DELETED flag
during APPEND/COPY)
e - perform EXPUNGE and expunge as a part of CLOSE.
a - administer (perform SETACL/DELETEACL/GETACL)
3.1.1. Obsolete rights
Due to ambiguity in RFC 2086 some existing RFC 2086 server implementations
use the "c" right to control the DELETE command. Others chose to use the
"d" right to control the DELETE command.
For the former group, let's define the "create" right as union of the "k"
and "x" rights, and the "delete" right as union of the "e" and "t" rights.
For the latter group, let's define the "create" rights as a synonym to the
"k" right, and the "delete" right as union of the "e", "t" and "x" rights.
For compatibility with RFC 2086 this section defines two virtual rights
"d" and "c".
If a client includes the "d" right in a rights list, then it MUST be
treated as if the client had included every member of the "delete" right.
(It is not an error for a client to specify both the "d" right and
one or more member of the "delete" right, but the effect is no different
than if just the "d" right or all members of the "delete" right had been
specified). When all the "delete" member rights are set in a list of
rights, the server MUST also include the "d" right when returning
the list in a MYRIGHTS or ACL response.
If member of the "delete" right are not tied together, the "d" right
MUST NOT be returned in a LISTRIGHTS response.
If a client includes the "c" right in a rights list, then it MUST be
treated as if the client had included every member of the "create" right.
(It is not an error for a client to specify both the "c" right and
one or more member of the "create" right, but the effect is no different
than if just the "c" right or all members of the "create" right had been
specified). When all the "create" member rights are set in a list of
rights, the server MUST also include the "c" right when returning
the list in a MYRIGHTS or ACL response.
If member of the "create" right are not tied together, the "c" right
MUST NOT be returned in a LISTRIGHTS response.
4. Access control management commands and responses
Servers, when processing a command that have an authentication identifier
as a parameter (i.e. any of SETACL, DELETEACL and LISTRIGHTS commands),
SHOULD first prepare the received identifier using "SASLprep" profile
[SASLprep] of the "stringprep" algorithm [StringPrep]. If the
preparation of the identifier fails or results in an empty string, the
server MUST refuse to perform the command with a BAD response.
4.1. SETACL command
Arguments: mailbox name
authentication identifier
access right modification
Data: no specific data for this command
Result: OK - setacl completed
NO - setacl failure: can't set acl
BAD - arguments invalid
The SETACL command changes the access control list on the
specified mailbox so that the specified identifier is granted
permissions as specified in the third argument.
The third argument is a string containing an optional plus ("+")
or minus ("-") prefix, followed by zero or more rights characters.
If the string starts with a plus, the following rights are added
to any existing rights for the identifier. If the string starts
with a minus, the following rights are removed from any existing
rights for the identifier. If the string does not start with a
plus or minus, the rights replace any existing rights for the
identifier.
Note, that an unrecognized right MUST cause the command to return
the BAD response. In particular, server MUST NOT silently ignore
unrecognized rights.
Example: C: A001 SETACL INBOX.Drafts Chris lrswicda
S: A001 OK Setacl complete
C: A035 SETACL INBOX.Drafts John lrQswicda
S: A035 BAD Uppercase rights are not allowed
C: A036 SETACL INBOX.Drafts John lrqswicda
S: A036 BAD The q right is not supported
4.2. DELETEACL command
Arguments: mailbox name
authentication identifier
Data: no specific data for this command
Result: OK - deleteacl completed
NO - deleteacl failure: can't delete acl
BAD - arguments invalid
The DELETEACL command removes any <identifier,rights> pair for the
specified identifier from the access control list for the specified
mailbox.
4.3. GETACL command
Arguments: mailbox name
Data: untagged responses: ACL
Result: OK - getacl completed
NO - getacl failure: can't get acl
BAD - arguments invalid
The GETACL command returns the access control list for mailbox in
an untagged ACL response.
Some implementations may permit multiple forms of an authentication
identifier to reference the same IMAP account. Usually, such
implementations will have a canonical form that is stored internally.
An ACL response caused by an GETACL command may include a
canonicalized form of the authentication identifier which might be
different from the one used in the corresponding SETACL command.
Example: C: A002 GETACL INBOX
S: * ACL INBOX Fred rwipslda
S: A002 OK Getacl complete
4.4. LISTRIGHTS command
Arguments: mailbox name
authentication identifier
Data: untagged responses: LISTRIGHTS
Result: OK - listrights completed
NO - listrights failure: can't get rights list
BAD - arguments invalid
The LISTRIGHTS command takes a mailbox name and an identifier and
returns information about what rights may be granted to the identifier
in the ACL for the mailbox.
Some implementations may permit multiple forms of an authentication
identifier to reference the same IMAP account. Usually, such
implementations will have a canonical form that is stored internally.
A LISTRIGHTS response caused by a LISTRIGHTS command MUST always
return the same form of an authentication identifier as specified
by the client. This is to allow the client to correlate the response
with the command.
Example: C: a001 LISTRIGHTS ~/Mail/saved smith
S: * LISTRIGHTS ~/Mail/saved smith la r swicd
S: a001 OK Listrights completed
C: a005 LISTRIGHTS archive.imap anyone
S: * LISTRIGHTS archive.imap anyone "" l r s w i p c d a
0 1 2 3 4 5 6 7 8 9
S: a005 Listrights successful
4.5. MYRIGHTS command
Arguments: mailbox name
Data: untagged responses: MYRIGHTS
Result: OK - myrights completed
NO - myrights failure: can't get rights
BAD - arguments invalid
The MYRIGHTS command returns the set of rights that the user has
to mailbox in an untagged MYRIGHTS reply.
Example: C: A003 MYRIGHTS INBOX
S: * MYRIGHTS INBOX rwipslda
S: A003 OK Myrights complete
4.6. ACL response
Data: mailbox name
zero or more identifier rights pairs
The ACL response occurs as a result of a GETACL command. The first
string is the mailbox name for which this ACL applies. This is
followed by zero or more pairs of strings, each pair contains the
identifier for which the entry applies followed by the set of
rights that the identifier has.
4.7. LISTRIGHTS response
Data: mailbox name
identifier
required rights
list of optional rights
The LISTRIGHTS response occurs as a result of a LISTRIGHTS
command. The first two strings are the mailbox name and identifier
for which this rights list applies. Following the identifier is a
string containing the (possibly empty) set of rights the
identifier will always be granted in the mailbox.
Following this are zero or more strings each containing a set of
rights the identifier may be granted in the mailbox. Rights
mentioned in the same string are tied together--either all must be
granted to the identifier in the mailbox or none may be granted.
The same right may not be listed more than once in the LISTRIGHTS
command.
4.8. MYRIGHTS response
Data: mailbox name
rights
The MYRIGHTS response occurs as a result of a MYRIGHTS command.
The first string is the mailbox name for which these rights apply.
The second string is the set of rights that the client has.
5. Rights required to perform different IMAP4rev1 commands
Before executing a command an ACL compliant server must check which rights Before executing a command an ACL compliant server must check which rights
are required to perform it. This section groups command by functions are required to perform it. This section groups command by functions
they perform and list the rights required. It also gives the detailed they perform and list the rights required. It also gives the detailed
description of any special processing required. description of any special processing required.
For the purpose of this section the UID counterpart of a command is
considered to be the same command, e.g. both UID COPY and COPY commands
require the same set of rights.
The table below summarizes different rights or their combinations that are The table below summarizes different rights or their combinations that are
required in order to perform different IMAP operations. As it is not always required in order to perform different IMAP operations. As it is not always
possible to express complex right checking and interactions, the description possible to express complex right checking and interactions, the description
after the table should be used as the primary reference. after the table should be used as the primary reference.
+---------------------+---+---+---+---+---+---+---+---+---+---+-----+------+ +---------------------+---+---+---+---+---+---+---+---+---+---+-----+------+
| Operations\Rights | l | r | s | w | i | c | x | t | e | a | Any | None | | Operations\Rights | l | r | s | w | i | k | x | t | e | a | Any | None |
+---------------------+---+---+---+---+---+---+---+---+---+---+-----+------+ +---------------------+---+---+---+---+---+---+---+---+---+---+-----+------+
| LIST | + | | | | | | | | | | | | | LIST | + | | | | | | | | | | | |
| SUBSCRIBE | * | | | | | | | | | | | * | | SUBSCRIBE | * | | | | | | | | | | | * |
| UNSUBSCRIBE | | | | | | | | | | | | + | | UNSUBSCRIBE | | | | | | | | | | | | + |
| LSUB | * | | | | | | | | | | | * | | LSUB | * | | | | | | | | | | | * |
| CREATE (for parent) | | | | | | + | | | | | | | | CREATE (for parent) | | | | | | + | | | | | | |
| DELETE | | | | | | | + | | | | | | | DELETE | | | | | | | + | ? | ? | | | |
| RENAME | | | | | | + | + | | | | | | | RENAME | | | | | | + | + | | | | | |
| COPY/APPEND | | | ? | ? | + | | | ? | | | | | | COPY/APPEND | | | ? | ? | + | | | ? | | | | |
| EXPUNGE/CLOSE | | | | | | | | | + | | | | | EXPUNGE/CLOSE | | | | | | | | | + | | | |
|SELECT/EXAMINE/STATUS| | + | | | | | | | | | | | |SELECT/EXAMINE/STATUS| | + | | | | | | | | | | |
| FETCH | | | ? | | | | | | | | | | | FETCH | | | ? | | | | | | | | | |
| STORE flags | | | ? | ? | | | | ? | | | | | | STORE flags | | | ? | ? | | | | ? | | | | |
| SETACL/DELETEACL | | | | | | | | | | + | | | | SETACL/DELETEACL | | | | | | | | | | + | | |
| GETACL/LISTRIGHTS | | | | | | | | | | + | | | | GETACL/LISTRIGHTS | | | | | | | | | | + | | |
| MYRIGHTS | | | | | | | | | | | + | | | MYRIGHTS | | | | | | | | | | | + | |
+---------------------+---+---+---+---+---+---+---+---+---+---+-----+------+ +---------------------+---+---+---+---+---+---+---+---+---+---+-----+------+
Legend: Legend:
+ - The right is required + - The right is required
* - Only one of the rights marked with * is required (see description below) * - Only one of the rights marked with * is required (see description below)
? - The right is optional (see description below) ? - The right is optional (see description below)
"Any" - at least one of the "l", "r", "i", "c", "x", "a" rights is "Any" - at least one of the "l", "r", "i", "k", "x", "a" rights is
required required
"None" - No rights required to perform the command "None" - No rights required to perform the command
Listing and subscribing/unsubscribing mailboxes: Listing and subscribing/unsubscribing mailboxes:
LIST - "l" right is required. LIST - "l" right is required.
Note, that if the user has "l" right to a mailbox "A/B", but not to its parent Note, that if the user has "l" right to a mailbox "A/B", but not to its parent
mailbox "A", the LIST command should behave as if the mailbox "A" doesn't exist, mailbox "A", the LIST command should behave as if the mailbox "A" doesn't exist,
for example: for example:
C: A777 LIST "" * C: A777 LIST "" *
skipping to change at line 246 skipping to change at line 444
SUBSCRIBE - "l" right is required only if the server checks for mailbox existence SUBSCRIBE - "l" right is required only if the server checks for mailbox existence
when performing SUBSCRIBE. when performing SUBSCRIBE.
UNSUBSCRIBE - no rights required to perform this operation. UNSUBSCRIBE - no rights required to perform this operation.
LSUB - "l" right is required only if the server checks for mailbox existence when LSUB - "l" right is required only if the server checks for mailbox existence when
performing SUBSCRIBE. performing SUBSCRIBE.
Mailbox management: Mailbox management:
CREATE - "c" right on a nearest existing parent mailbox. When a new CREATE - "k" right on a nearest existing parent mailbox. When a new
mailbox is created it SHOULD inherit the ACL from the parent mailbox is created it SHOULD inherit the ACL from the parent
mailbox (if one exists) in the defined hierarchy. mailbox (if one exists) in the defined hierarchy.
DELETE - "x" right on the mailbox. DELETE - "x" right on the mailbox. Note, that some servers don't allow
to delete a non-empty mailbox. If this is the case, the user
also need both "e" and "t" rights, in order to make the mailbox
empty first.
RENAME - Moving a mailbox from one parent to another The DELETE command MUST delete the ACL associated with the
requires "x" right on the mailbox itself and "c" right for deleted mailbox.
the new parent. For example, if the user wants to rename
mailbox named "A/B/C" to "D/E", the user must have "x" right RENAME - Moving a mailbox from one parent to another requires the "x" right
for the mailbox "A/B/C" and "c" right for the mailbox "D". on the mailbox itself and the "k" right for the new parent.
For example, if the user wants to rename mailbox named "A/B/C" to
"D/E", the user must have the "x" right for the mailbox "A/B/C"
and the "k" right for the mailbox "D".
The RENAME command SHOULD NOT change the ACLs on the renamed The RENAME command SHOULD NOT change the ACLs on the renamed
mailbox and submailboxes. mailbox and submailboxes.
Copying or appending messages: Copying or appending messages:
Before performing a COPY/APPEND command the server MUST check if the Before performing a COPY/APPEND command the server MUST check if the
user has "i" right for the target mailbox. If the user doesn't have "i" user has "i" right for the target mailbox. If the user doesn't have "i"
right, the operation fails. Otherwise for each copied/appended message right, the operation fails. Otherwise for each copied/appended message
the server MUST check if the user has the server MUST check if the user has
skipping to change at line 320 skipping to change at line 524
S: * 79 FETCH (FLAGS (\Seen)) S: * 79 FETCH (FLAGS (\Seen))
S: A007 OK Fetch Completed S: A007 OK Fetch Completed
In the latter case \Answered, $Forwarded and \Draft flags were lost In the latter case \Answered, $Forwarded and \Draft flags were lost
on COPY, as the user has no "w" right in the target mailbox. on COPY, as the user has no "w" right in the target mailbox.
Expunging the selected mailbox: Expunging the selected mailbox:
EXPUNGE - "e" right on the selected mailbox. EXPUNGE - "e" right on the selected mailbox.
CLOSE - "e" right on the selected mailbox. If the server is unable to CLOSE - "e" right on the selected mailbox. If the server is unable to
expunge the mailb expunge the mailbox because the user doesn't have the "e" right,
ox because the user doesn't have the "e" right,
the server MUST ignore expunge request, close the mailbox the server MUST ignore expunge request, close the mailbox
and return tagged OK response. and return tagged OK response.
Fetch information about a mailbox and its messages: Fetch information about a mailbox and its messages:
SELECT/EXAMINE/STATUS - "r" right on the mailbox. SELECT/EXAMINE/STATUS - "r" right on the mailbox.
FETCH - A FETCH request that implies setting \Seen flag MUST NOT set it, FETCH - A FETCH request that implies setting \Seen flag MUST NOT set it,
if the current user doesn't have "s" right. if the current user doesn't have "s" right.
Changing flags: Changing flags:
skipping to change at line 347 skipping to change at line 550
one flag specified in the STORE, as the tagged NO response to a STORE one flag specified in the STORE, as the tagged NO response to a STORE
command is not handled very well by deployed clients. command is not handled very well by deployed clients.
Changing ACLs: Changing ACLs:
SETACL/DELETEACL - "a" right on the mailbox. SETACL/DELETEACL - "a" right on the mailbox.
Reading ACLs: Reading ACLs:
GETACL - "a" right on the mailbox. GETACL - "a" right on the mailbox.
MYRIGHTS - any of the following rights is required to perform MYRIGHTS - any of the following rights is required to perform
the operation: "l", "r", "i", "c", "x", "a". the operation: "l", "r", "i", "k", "x", "a".
<<A previous version included "e" in the list. This explanation will be deleted
before publication:
Is there a particular reason why "s", "w", "t", "m" and "n" are excluded from
this list? - Yes, because flags can't be changed unless the "r" is also granted
(i.e. the mailbox can be SELECTed/EXAMINEd). But the same applies to "e"!>>
LISTRIGHTS - "a" right on the mailbox. LISTRIGHTS - "a" right on the mailbox.
5. Other considerations 6. Other considerations
5.1. Additional requirements and Implementation notes 6.1. Additional requirements and Implementation notes
5.1.1. Servers 6.1.1. Servers
This document defines an additional capability that is used to announce This document defines an additional capability that is used to announce
the list of extra rights (excluding the ones defined in the RFC 2086) the list of extra rights (excluding the ones defined in the RFC 2086)
supported by the server. The set of rights MUST include "t", "e", "x", "m" supported by the server. The set of rights MUST include "t", "e", "x" and "k".
and "n". Note, that the extra rights can appear in any order. Note, that the extra rights can appear in any order.
Example: C: 1 capability Example: C: 1 capability
S: * CAPABILITY IMAP4REV1 STARTTLS LITERAL+ ACL RIGHTS=texnm S: * CAPABILITY IMAP4REV1 STARTTLS LITERAL+ ACL RIGHTS=texk
S: 1 OK completed S: 1 OK completed
The presence of the "RIGHTS=" capability also declares that the server
always returns the MYRIGHTS response code upon SELECT/EXAMINE (see also
section 5.3). The MYRIGHTS response code SHOULD also be sent any time
when the server detects that the set of rights allowed for the logged
in user in the opened mailbox has changed.
Any server implementing an ACL extension MUST accurately reflect the current Any server implementing an ACL extension MUST accurately reflect the current
user's rights in FLAGS and PERMANENTFLAGS responses. user's rights in FLAGS and PERMANENTFLAGS responses.
Example: C: A142 SELECT INBOX Example: C: A142 SELECT INBOX
S: * 172 EXISTS S: * 172 EXISTS
S: * 1 RECENT S: * 1 RECENT
S: * OK [MYRIGHTS rwis] You have the rigths
S: * OK [UNSEEN 12] Message 12 is first unseen S: * OK [UNSEEN 12] Message 12 is first unseen
S: * OK [UIDVALIDITY 3857529045] UIDs valid S: * OK [UIDVALIDITY 3857529045] UIDs valid
S: * OK [UIDNEXT 4392] Predicted next UID S: * OK [UIDNEXT 4392] Predicted next UID
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * OK [PERMANENTFLAGS (\Seen \Answered \Flagged \*)] Limited S: * OK [PERMANENTFLAGS (\Seen \Answered \Flagged \*)] Limited
S: A142 OK [READ-WRITE] SELECT completed S: A142 OK [READ-WRITE] SELECT completed
C: A143 MYRIGHTS INBOX
S: * MYRIGHTS INBOX rwis
S: A143 OK completed
Servers MAY cache the rights a user has on a mailbox when the mailbox Servers MAY cache the rights a user has on a mailbox when the mailbox
is selected, so that if a client's rights on a mailbox are changed with is selected, so that if a client's rights on a mailbox are changed with
SETACL or DELETEACL, commands specific to the selected state (e.g., STORE, SETACL or DELETEACL, commands specific to the selected state (e.g., STORE,
EXPUNGE) might not reflect the changed rights until the mailbox is EXPUNGE) might not reflect the changed rights until the mailbox is
re-selected. If the server checks the rights on each command, then it SHOULD re-selected. If the server checks the rights on each command, then it SHOULD
send FLAGS and PERMANENTFLAGS responses if they have changed. send FLAGS and PERMANENTFLAGS responses if they have changed.
An ACL server MAY modify one or more ACL for one or more identifier as a An ACL server MAY modify one or more ACL for one or more identifier as a
side effect of modifying the ACL specified in a SETACL/DELETEACL. side effect of modifying the ACL specified in a SETACL/DELETEACL.
If the server does that it MUST send untagged ACL response to notify the If the server does that it MUST send untagged ACL response to notify the
client about the changes made. client about the changes made.
5.1.2. Clients 6.1.2. Clients
A client implementation that allows a user to read and update ACLs MUST A client implementation that allows a user to read and update ACLs MUST
preserve unrecognized rights that it doesn't allow the user to change preserve unrecognized rights that it doesn't allow the user to change
when updating the rights. Otherwise the client may unintentionally remove when updating the rights. Otherwise the client may unintentionally remove
permissions. permissions.
5.2. Mapping of ACL rights to READ-WRITE and READ-ONLY response codes 6.2. Mapping of ACL rights to READ-WRITE and READ-ONLY response codes
A particular ACL server implementation may allow "shared multiuser A particular ACL server implementation may allow "shared multiuser
access" to some mailboxes. "Shared multiuser access" to a mailbox means access" to some mailboxes. "Shared multiuser access" to a mailbox means
that multiple different users are able to access the same mailbox, that multiple different users are able to access the same mailbox,
if they have proper access rights. "Shared multiuser access" to the if they have proper access rights. "Shared multiuser access" to the
mailbox doesn't mean that the ACL for the mailbox is currently set mailbox doesn't mean that the ACL for the mailbox is currently set
to allow access by multiple users. Let's denote a "shared multiuser to allow access by multiple users. Let's denote a "shared multiuser
write access" as a "shared multiuser access" when a user may be write access" as a "shared multiuser access" when a user may be
granted flag modification rights (any of "w", "s" or "t"). granted flag modification rights (any of "w", "s" or "t").
Section 4 describes which rights are required for modifying different flags. Section 5 describes which rights are required for modifying different flags.
If the ACL server implements some flags as shared for a mailbox (i.e., If the ACL server implements some flags as shared for a mailbox (i.e.,
the ACL for the mailbox may be set up so that changes to those flags are the ACL for the mailbox may be set up so that changes to those flags are
visible to another user), let's call the set of rights associated with these visible to another user), let's call the set of rights associated with these
flags (as described in Section 4) for that mailbox collectively as flags (as described in Section 5) for that mailbox collectively as
"shared flag rights". Note, that "shared flag rights" set MAY be different "shared flag rights". Note, that "shared flag rights" set MAY be different
for different mailboxes. for different mailboxes.
If the server doesn't support "shared multiuser write access" to a If the server doesn't support "shared multiuser write access" to a
mailbox or doesn't implement shared flags on the mailbox, "shared flag mailbox or doesn't implement shared flags on the mailbox, "shared flag
rights" for the mailbox is defined to be the empty set. rights" for the mailbox is defined to be the empty set.
Example 1: Mailbox "banan" allows "shared multiuser write access" and Example 1: Mailbox "banan" allows "shared multiuser write access" and
implements flags \Deleted, \Answered and $MDNSent as implements flags \Deleted, \Answered and $MDNSent as
shared flags. "Shared flag rights" for the mailbox "banan" shared flags. "Shared flag rights" for the mailbox "banan"
skipping to change at line 454 skipping to change at line 646
implements \Seen system flag as shared flag. "Shared flag implements \Seen system flag as shared flag. "Shared flag
rights" for the mailbox "apple" contains "s" right, rights" for the mailbox "apple" contains "s" right,
because system flag \Seen requires "s" right. because system flag \Seen requires "s" right.
Example 3: Mailbox "pear" allows "shared multiuser write access" and Example 3: Mailbox "pear" allows "shared multiuser write access" and
implements flags \Seen, \Draft as shared flags. "Shared flag implements flags \Seen, \Draft as shared flags. "Shared flag
rights" for the mailbox "apple" is a set containing flags "s" rights" for the mailbox "apple" is a set containing flags "s"
(because system flag \Seen requires "s" right) and "w" (because system flag \Seen requires "s" right) and "w"
(because system flag \Draft requires "w" right). (because system flag \Draft requires "w" right).
The server MUST include a READ-ONLY prefix in the tagged OK response to The server MUST include a READ-ONLY response code in the tagged OK response to
a SELECT command if none of the following rights is granted to the a SELECT command if none of the following rights is granted to the
current user: current user:
"i", "e" and "shared flag rights". "i", "e" and "shared flag rights"*.
The server SHOULD include a READ-WRITE prefix in the tagged OK response The server SHOULD include a READ-WRITE response code in the tagged OK response
if at least one of the "i", "e" or "shared flag rights" is granted to the if at least one of the "i", "e" or "shared flag rights"* is granted to the
current user. current user.
* - Note that a future extension to this document may extend the list of
rights that causes the server to return the READ-WRITE response code.
Example 1 (continued): The user that has "lrs" rights for the mailbox Example 1 (continued): The user that has "lrs" rights for the mailbox
"banan". The server returns READ-ONLY response "banan". The server returns READ-ONLY response
code on SELECT, as none of "iewt" rights is code on SELECT, as none of "iewt" rights is
granted to the user. granted to the user.
Example 2 (continued): The user that has "rit" rights for the mailbox Example 2 (continued): The user that has "rit" rights for the mailbox
"apple". The server returns READ-WRITE response "apple". The server returns READ-WRITE response
code on SELECT, as the user has "i" right. code on SELECT, as the user has "i" right.
Example 3 (continued): The user that has "rset" rights for the mailbox Example 3 (continued): The user that has "rset" rights for the mailbox
"pear". The server returns READ-WRITE response "pear". The server returns READ-WRITE response
code on SELECT, as the user has "e" and "s" rights. code on SELECT, as the user has "e" and "s" rights.
5.3. MYRIGHTS response code 7. Security Considerations
Data: rights
The MYRIGHTS response code is sent in an untagged OK response
that results from SELECT/EXAMINE. Also this response code can be
sent at any time after opening a mailbox when the server detects
that the set of rights allowed for the logged in user has changed.
The MYRIGHTS response code is equivalent to the MYRIGHTS untagged
response for the selected mailbox.
6. Security Considerations
An implementation must make sure the ACL commands themselves do not An implementation must make sure the ACL commands themselves do not
give information about mailboxes with appropriately restricted ACL's. give information about mailboxes with appropriately restricted ACL's.
For example, a GETACL command on a mailbox for which the user has For example, a GETACL command on a mailbox for which the user has
insufficient rights should not admit that the mailbox exists, much less insufficient rights should not admit that the mailbox exists, much less
return the mailbox's ACL. return the mailbox's ACL.
LISTRIGHTS command MUST NOT check that a particular identifier exists, LISTRIGHTS command MUST NOT check that a particular identifier exists,
however it SHOULD recognize special identifiers like "anyone". however it SHOULD recognize special identifiers like "anyone".
IMAP clients implementing ACL that are able to modify ACLs SHOULD IMAP clients implementing ACL that are able to modify ACLs SHOULD
warn a user that wants to give full access (or even just the "a" right) warn a user that wants to give full access (or even just the "a" right)
to the special identifier "anyone". to the special identifier "anyone".
skipping to change at line 503 skipping to change at line 685
insufficient rights should not admit that the mailbox exists, much less insufficient rights should not admit that the mailbox exists, much less
return the mailbox's ACL. return the mailbox's ACL.
LISTRIGHTS command MUST NOT check that a particular identifier exists, LISTRIGHTS command MUST NOT check that a particular identifier exists,
however it SHOULD recognize special identifiers like "anyone". however it SHOULD recognize special identifiers like "anyone".
IMAP clients implementing ACL that are able to modify ACLs SHOULD IMAP clients implementing ACL that are able to modify ACLs SHOULD
warn a user that wants to give full access (or even just the "a" right) warn a user that wants to give full access (or even just the "a" right)
to the special identifier "anyone". to the special identifier "anyone".
7. Formal Syntax 8. Formal Syntax
This document doesn't change the formal syntax of commands/
responses defined in the Section 6 of RFC 2086. However,
the "identifier" production is now allowed to carry any UTF-8 string.
Formal syntax is defined using ABNF [ABNF] as modified by [IMAP4]. Formal syntax is defined using ABNF [ABNF] as modified by [IMAP4].
Non-terminals referenced but not defined below are as defined by Non-terminals referenced but not defined below are as defined by
[IMAP4]. [IMAP4].
Except as noted otherwise, all alphabetic characters are Except as noted otherwise, all alphabetic characters are
case-insensitive. The use of upper or lower case characters to case-insensitive. The use of upper or lower case characters to
define token strings is for editorial clarity only. Implementations define token strings is for editorial clarity only. Implementations
MUST accept these strings in a case-insensitive fashion. MUST accept these strings in a case-insensitive fashion.
LOWER_ALPHA = %x61-7A ;; a-z
acl_data = "ACL" SP mailbox *(SP identifier SP
rights)
deleteacl = "DELETEACL" SP mailbox SP identifier
getacl = "GETACL" SP mailbox
identifier = astring
listrights = "LISTRIGHTS" SP mailbox SP identifier
listrights_data = "LISTRIGHTS" SP mailbox SP identifier
SP rights *(SP rights)
mod_rights = astring
;; +rights to add, -rights to remove
;; rights to replace
myrights = "MYRIGHTS" SP mailbox
myrights_data = "MYRIGHTS" SP mailbox SP rights
new_rights = 1*(LOWER_ALPHA / DIGIT)
;; MUST include "t", "e", "x" and "k"
rights = astring
;; only lowercase ASCII letters and digits
;; are allowed.
rights_capa = "RIGHTS=" new_rights rights_capa = "RIGHTS=" new_rights
;; RIGHTS=... capability ;; RIGHTS=... capability
setacl = "SETACL" SP mailbox SP identifier
SP mod_rights
new_rights = rights 9. IANA Considerations
;; MUST include "t", "e", "x", "m" and "n"
resp-text-code =/ myrights_rspcod IMAP4 capabilities are registered by publishing a standards track or
IESG approved experimental RFC. The registry is currently located
at:
myrights_rspcod = "MYRIGHTS" SP rights http://www.iana.org/assignments/imap4-capabilities
rights = atom This document defines the RIGHTS= IMAP capability. IANA is requested
;; MUST NOT contain leading "+" or "-" to add this capability to the registry.
;; MUST be treated as case-sensitive
8. References 10. References
8.1. Normative References 10.1. Normative References
[KEYWORDS] Bradner, "Key words for use in RFCs to Indicate [KEYWORDS] Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, Harvard University, March 1997. Requirement Levels", RFC 2119, Harvard University, March 1997.
[ABNF] Crocker, Overell, "Augmented BNF for Syntax Specifications: [ABNF] Crocker, Overell, "Augmented BNF for Syntax Specifications:
ABNF", RFC 2234, Internet Mail Consortium, Demon Internet Ltd, ABNF", RFC 2234, Internet Mail Consortium, Demon Internet Ltd,
November 1997. November 1997.
[IMAP4] Crispin, M., "Internet Message Access Protocol - Version [IMAP4] Crispin, M., "Internet Message Access Protocol - Version
4rev1", RFC 3501, University of Washington, March 2003. 4rev1", RFC 3501, University of Washington, March 2003.
[RFC2086] Myers, J., "IMAP4 ACL extension", RFC 2086, Carnegie Mellon,
January 1997
[UTF-8] Yergeau, F., "UTF-8, a transformation format of IS0 10646", [UTF-8] Yergeau, F., "UTF-8, a transformation format of IS0 10646",
RFC 3629, Alis Technologies, November 2003. RFC 3629, Alis Technologies, November 2003.
8.2. Informative References [Stringprep] Hoffman, P., Blanchet, M., "Preparation of
Internationalized Strings ("stringprep")", RFC 3454, December 2002.
[ANNOTATE] Gellens, R. and C. Daboo, "IMAP ANNOTATE Extension",
work in progress, draft-ietf-imapext-annotate-XX.txt
9. Acknowledgment [SASLprep] Zeilenga, K., "SASLprep: Stringprep profile for user names
and passwords", Work in progress, draft-ietf-sasl-saslprep-XX.txt.
This document is an update to the RFC 2086 written by John G. Myers. 10.2. Informative References
Editor appreciates comments received from Mark Crispin, Chris Newman, [RFC2086] Myers, J., "IMAP4 ACL extension", RFC 2086, Carnegie Mellon,
Cyrus Daboo, John G. Myers, Steve Hole, Curtis King, Lyndon Nerenberg, January 1997.
Larry Greenfield, Robert Siemborski, Vladimir Butenko, Dave Cridland,
Harrie Hazewinkel, Philip Guenther, Brian Candler and other participants
of the IMAPEXT working group.
10. Editor's Address 11. Editor's Address
Alexey Melnikov Alexey Melnikov
email: alexey.melnikov@isode.com email: alexey.melnikov@isode.com
Isode Limited Isode Limited
11. IPR Disclosure Acknowledgement 12. IPR Disclosure Acknowledgement
By submitting this Internet-Draft, I certify that any applicable By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been disclosed, patent or other IPR claims of which I am aware have been disclosed,
and any of which I become aware will be disclosed, in accordance with and any of which I become aware will be disclosed, in accordance with
RFC 3668. RFC 3668.
12. Intellectual Property Statement 13. Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of claims of rights made available for publication and any assurances of
skipping to change at line 603 skipping to change at line 807
obtain a general license or permission for the use of such obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat. be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive this standard. Please address the information to the IETF Executive
Director. Director.
13. Full Copyright Statement 14. Full Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78 and to the rights, licenses and restrictions contained in BCP 78 and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
skipping to change at line 629 skipping to change at line 833
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
Appendix A. Changes since RFC 2086 Appendix A. Changes since RFC 2086
1. Changed the charset of "identifier" from US-ASCII to UTF-8. 1. Changed the charset of "identifier" from US-ASCII to UTF-8.
2. Specified that mailbox deletion is controled by the "x" right and 2. Specified that mailbox deletion is controled by the "x" right and
EXPUNGE is controlled by the "e" right. EXPUNGE is controlled by the "e" right.
3. Clarified that RENAME requires the "c" right for the new parent and 3. Added the "t" right that controls STORE \Deleted. Redefined the "d"
the "x" right for the old name. right to be a macro for "e", "t" and possibly "x".
4. Added the "t" right that controls STORE \Deleted. Redefined the "d" 4. Added the "k" right that controls CREATE. Redefined the "c"
right to be a macro for "e", "x" and "t". right to be a macro for "k" and possibly "x".
5. Specified that the "a" right also controls DELETEACL. 5. Specified that the "a" right also controls DELETEACL.
6. Specified that the "r" right also controls STATUS. 6. Specified that the "r" right also controls STATUS.
7. Removed the requirement to check the "r" right for CHECK, SEARCH and 7. Removed the requirement to check the "r" right for CHECK, SEARCH and
FETCH, as this is required for SELECT/EXAMINE to be successful. FETCH, as this is required for SELECT/EXAMINE to be successful.
8. LISTRIGHTS requires the "a" right on the mailbox (same as SETACL). 8. LISTRIGHTS requires the "a" right on the mailbox (same as SETACL).
skipping to change at line 659 skipping to change at line 863
11. SUBSCRIBE is NOT allowed with the "r" right. 11. SUBSCRIBE is NOT allowed with the "r" right.
12. Specified that the "l" right controls SUBSCRIBE. 12. Specified that the "l" right controls SUBSCRIBE.
13. GETACL is NOT allowed with the "r" right, even though there are 13. GETACL is NOT allowed with the "r" right, even though there are
several implementations that allows that. If a user only has "r" several implementations that allows that. If a user only has "r"
right, GETACL can disclose information about identifiers existing right, GETACL can disclose information about identifiers existing
on the mail system. on the mail system.
14. Added new section that describes which rights are required and/or 14. Clarified that RENAME requires the "k" right for the new parent and
the "x" right for the old name.
15. Added new section that describes which rights are required and/or
checked when performing various IMAP commands. checked when performing various IMAP commands.
15. Added mail client security considerations when dealing with special 16. Added mail client security considerations when dealing with special
identifier "anyone". identifier "anyone".
16. Clarified that negative rights are not the same as DELETEACL. 17. Clarified that negative rights are not the same as DELETEACL.
17. Added note that a server can modify an ACL for any identifier(s) as a 18. Added "Compatibility with RFC 2086" section.
side effect of performing SETACL/DELETEACL. Also specified that
the server MUST send untagged ACL response if it does that.
18. Added section about mapping of ACL rights to READ-WRITE and READ-ONLY 19. Added section about mapping of ACL rights to READ-WRITE and READ-ONLY
response codes. response codes.
19. Added "Compatibility with RFC 2086" section. 20. Changed BNF to ABNF.
20. Added "Implementation Notes" section.
21. Updated "References" section.
22. Added requirement for a SELECT/EXAMINE to return the MYRIGHTS
response.
23. Added the "m" and "n" rights for ANNOTATE. 21. Added "Implementation Notes" section.
24. Added MYRIGHTS response code. 22. Updated "References" section.
Appendix B. Compatibility with RFC 2086 Appendix B. Compatibility with RFC 2086
This section gives guidelines how an existing RFC 2086 server This section gives guidelines how an existing RFC 2086 server
implementation may be updated to comply with this document. implementation may be updated to comply with this document.
This document splits the "d" right into 3 new different rights "x", "t" This document splits the "d" right into several new different rights: "t",
and "e". The "d" right remains for backwards-compatibility but it is a "e" and possibly "x" (see section 3.1.1 for more details). The "d" right
virtual right. See section 3 for details. The server should imple remains for backwards-compatibility but it is a virtual right. The server
ment should implement one of the following two approaches to handle the "d" right
one of the following two approaches to handle the "d" right and the new and the new rights that have replaced it.
rights that have replaced<<>> it.
a). Tie "x", "t" and "e" together - almost no changes.
b). Implement separate "x", "t" and "e". Return "d" right in a
MYRIGHTS response/response code and an ACL response containing ACL
information when all three of "x", "t" and "e" are granted.
Additional work required to implement the RIGHTS extension when RFC 2086 a). "t", "e" (and possibly "x) together - almost no changes.
is already implemented: b). Implement separate "x", "t" and "e". Return the "d" right in a
MYRIGHTS response or an ACL response containing ACL
information when all of the "t", "e" (and "x") are granted.
1). Send the MYRIGHTS untagged response on a successful SELECT/EXAMINE. In a similar manner this document splits the "c" right into several new
different rights: "k" and possibly "x" (see section 3.1.1 for more details).
The "c" right remains for backwards-compatibility but it is a virtual right.
The server should implement one of the two approaches described above.
Also check Sections 7.1 and 7.2, as well as the appendix A to see Also check Sections 6.1 and 6.2, as well as the appendix A to see
other changes required. Server implementors should check which rights other changes required. Server implementors should check which rights
are required to invoke different IMAP4 commands as described in are required to invoke different IMAP4 commands as described in
Section 4. Section 5.
Appendix C. Known deficiencies
This specification has some known deficiencies including:
1. This is inadequate to provide complete read-write access to mailboxes
protected by Unix-style rights bits because there is no equivalent to
"chown" and "chgrp" commands nor is there a good way to discover such
limitations are present.
2. Because this extension leaves the specific semantics of how rights are
combined by the server and which rights are tied as implementation
defined, the ability to build a user-friendly interface is limited.
The work-in-progress "ACL2" extension is intended to redesign this
extension to address these deficiencies without the constraint of
backwards-compatibility and may eventually supercede this facility.
However, RFC 2086 is deployed in multiple implementations so this
intermediate step which fixes the straightforward deficiencies in a
backwards compatible fashion is considered worthwhile.
Appendix D. Acknowledgment
This document is a revision of the RFC 2086 written by John G. Myers.
Editor appreciates comments received from Mark Crispin, Chris Newman,
Cyrus Daboo, John G. Myers, Dave Cridland, Ken Murchison, Steve Hole,
Vladimir Butenko, Larry Greenfield, Robert Siemborski, Harrie
Hazewinkel, Philip Guenther, Brian Candler, Curtis King, Lyndon
Nerenberg and other participants of the IMAPEXT working group.
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