draft-ietf-imapext-2086upd-00.txt   draft-ietf-imapext-2086upd-01.txt 
IMAPEXT Working Group A. Melnikov IMAPEXT Working Group A. Melnikov
Internet Draft Editor Internet Draft Editor
Document: draft-ietf-imapext-2086upd-00.txt September 2004 Document: draft-ietf-imapext-2086upd-01.txt November 2004
Updates: 2086, <<3501?>> Updates: 2086, <<3501?>>
Expires: March 2005 Expires: May 2005
IMAP4 ACL extension - IMAP4 ACL extension -
updated list of rights 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.
skipping to change at line 50 skipping to change at line 49
Abstract Abstract
The ACL (Access Control List) extension [RFC2086] of the Internet Message The ACL (Access Control List) extension [RFC2086] of the Internet Message
Access Protocol [IMAP4] permits mailbox access control lists to be Access Protocol [IMAP4] permits mailbox access control lists to be
manipulated through the IMAP protocol. manipulated through the IMAP protocol.
This document updates the list of rights defined in RFC 2086. It This document updates the list of rights defined in RFC 2086. It
also clarifies which rights are required for different IMAP commands. also clarifies which rights are required for different IMAP commands.
0. Open issues and ToDo list
This section will be removed when the draft will be published as RFC.
It is intended to simplify discussion.
1). Do we want to add a requirement to send MYRIGHTS response on
SELECT/EXAMINE?
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 updates Section 3 of the RFC 2086. It also clarifies
different aspects of the RFC 2086, in particular use of UTF-8 in different aspects of the RFC 2086, in particular use of UTF-8 [UTF-8] in
identifiers, which rights are required for different IMAP4 commands; identifiers, which rights are required for different IMAP4 commands;
how READ-WRITE/READ-ONLY response codes are related to ACL>> 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. 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 an ordered list 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.
Identifier is a 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 user. 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. Letters are reserved for ''standard'' rights, listed
below. The set of standard rights may only be extended by a below. (Note that a right represented by a letter is case-sensitive,
standards-track document. Digits are reserved for implementation or e.g. the "r" right is not the same as the "R" right. <<problem?>>) The set of
site defined rights. The currently defined standard rights are standard rights may only be extended by a standards-track document.
(note, that the list below doesn't list all commands that use a Digits are reserved for implementation or site defined rights. The
particular right): 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) l - lookup (mailbox is visible to LIST/LSUB commands, SUBSCRIBE mailbox)
r - read (SELECT the mailbox, perform STATUS) r - read (SELECT the mailbox, perform STATUS)
s - keep seen/unseen information across sessions (set or clear \SEEN flag s - keep seen/unseen information across sessions (set or clear \SEEN flag
via STORE, APPEND or COPY) via STORE, APPEND or COPY)
w - write (set or clear flags other than \SEEN and \DELETED via STORE, w - write (set or clear flags other than \SEEN and \DELETED via STORE,
APPEND or COPY) APPEND or COPY)
i - insert (perform APPEND, COPY into mailbox) i - insert (perform APPEND, COPY into mailbox)
p - post (send mail to submission address for mailbox, p - post (send mail to submission address for mailbox,
not enforced by IMAP4 itself. not enforced by IMAP4 itself.
c - create mailboxes (CREATE new sub-mailboxes in any c - create mailboxes (CREATE new sub-mailboxes in any
implementation-defined hierarchy, parent mailbox for the new implementation-defined hierarchy, parent mailbox for the new
mailbox name in RENAME) mailbox name in RENAME)
When a new mailbox is created it SHOULD inherit rights from
the parent mailbox (if one exists) in the defined hierarchy.
x - delete mailbox (DELETE mailbox, old 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 t - delete messages (set or clear \DELETED flag via STORE, set \DELETED flag
during APPEND/COPY) during APPEND/COPY)
e - perform EXPUNGE and expunge as a part of CLOSE e - perform EXPUNGE and expunge as a part of CLOSE
d - This right is defined for backward compatibility with ACL d - This right is defined for backward compatibility with ACL
extension (RFC 2086). If a client sets "d" right, the server MUST extension (RFC 2086). See below for details on how servers
set "x", "e" and "t" rights. When the client clears the "d" right, should interpret it in commands that alter ACLs and when it
the server MUST clear "x", "e" and "t" rights. When all three of "x", should be included in responses that return ACLs or lists of
"e" and "t" are set, the server MUST return "d" right in response to rights.
a LIST (ACL) command. If "x", "e" and "t" rights are not tied together,
"d" right MUST NOT be returned in a LISTRIGHTS response.
a - administer (perform SETACL/DELETEACL/GETACL) a - administer (perform SETACL/DELETEACL/GETACL)
m - write private annotations [ANNOTATE]
n - write shared annotations [ANNOTATE] n - write shared annotations [ANNOTATE]
<<Add new right for private annotations, if required>>
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 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 may include rights to be granted to the identifier example, an ACL m
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 by using the MYRIGHTS command.
skipping to change at line 214 skipping to change at line 213
| 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 | | | | | | | | | | + | | | | GETACL/LISTRIGHTS | | | | | | | | | | + | | |
| MYRIGHTS/LISTRIGHTS | | | | | | | | | | | + | | | 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", "e", "a" rights is "Any" - at least one of the "l", "r", "i", "c", "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 "" *
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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 - "c" right on a nearest existing parent mailbox. When a new
mailbox is created it SHOULD inherit rights 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.
RENAME - Moving a mailbox from one parent to another RENAME - Moving a mailbox from one parent to another
requires "x" right on the mailbox itself and "c" right for requires "x" right on the mailbox itself and "c" right for
the new parent. For example, if the user wants to rename 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 mailbox named "A/B/C" to "D/E", the user must have "x" right
for the mailbox "A/B/C" and "c" right for the mailbox "D". for the mailbox "A/B/C" and "c" right for the mailbox "D".
The RENAME command SHOULD NOT change the ACLs on the renamed
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
"t" right - when the message has \Deleted flag set "t" right - when the message has \Deleted flag set
"s" right - when the message has \Seen flag set "s" right - when the message has \Seen flag set
"w" right for all other message flags. "w" right for all other message flags.
Only when the user has a particular right the corresponding flags are Only when the user has a particular right the corresponding flags are
skipping to change at line 318 skipping to change at line 320
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 mailbox because the user doesn't have the "e" right, expunge the mailb
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 344 skipping to change at line 347
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", "e", "a". the operation: "l", "r", "i", "c", "x", "a".
LISTRIGHTS - same as MYRIGHTS. <<?>> <<Same rights as for GETACL?>>
5. 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].
Non-terminals referenced but not defined below are as defined by
[IMAP4] or [LISTEXT].
Except as noted otherwise, all alphabetic characters are
case-insensitive. The use of upper or lower case characters to
define token strings is for editorial clarity only. Implementations
MUST accept these strings in a case-insensitive fashion.
rights_capa = "RIGTHS=" new_rights
;; RIGHTS=... capability
new_rights = atom
;; MUST include "t", "e", "x" and "n" <<ANNOTATE>>
6. Security Considerations <<A previous version included "e" in the list. This explanation will be deleted
before publication:
An implementation must make sure the ACL commands themselves do not Is there a particular reason why "s", "w", "t", "m" and "n" are excluded from
give information about mailboxes with appropriately restricted ACL's. this list? - Yes, because flags can't be changed unless the "r" is also granted
For example, a GETACL command on a mailbox for which the user has (i.e. the mailbox can be SELECTed/EXAMINEd). But the same applies to "e"!>>
insufficient rights should not admit that the mailbox exists, much less
return the mailbox's ACL.
LISTRIGHTS command MUST NOT check that a particular identifier exists, LISTRIGHTS - "a" right on the mailbox.
however it SHOULD recognize special identifiers like "anyone".
IMAP clients implementing ACL that are able to modify ACLs SHOULD 5. Other considerations
warn a user that wants to give full access (or even just "a" right)
to the special identifier "anyone".
7. Other considerations 5.1. Additional requirements and Implementation notes
7.1. Additional requirements and Implementation notes 5.1.1. 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" supported by the server. The set of rights MUST include "t", "e", "x", "m"
and "n" <<ANNOTATE>>. Note, that the extra rights can appear in any order. and "n". Note, that the extra rights can appear in any order.
Example: C: 1 capability Example: C: 1 capability
S: * CAPABILITY IMAP4REV1 STARTTLS LITERAL+ ACL RIGTHS=texn<<>> S: * CAPABILITY IMAP4REV1 STARTTLS LITERAL+ ACL RIGHTS=texnm
S: 1 OK completed S: 1 OK completed
A client implementation that allows a user to read and update ACL MUST The presence of the "RIGHTS=" capability also declares that the server
preserve unrecognized rights that it doesn't allow the user to change always returns the MYRIGHTS response code upon SELECT/EXAMINE (see also
when updating the rights. Otherwise the client may unintentionally remove section 5.3). The MYRIGHTS response code SHOULD also be sent any time
permissions. 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: A141 MYRIGHTS INBOX Example: C: A142 SELECT INBOX
S: * MYRIGHTS INBOX rwis
S: A141 OK Myrights complete
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
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
SETACL or DELETEACL, commands specific to the selected state (e.g., STORE,
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
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.
7.2. Mapping of ACL rights to READ-WRITE and READ-ONLY response codes 5.1.2. Clients
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
when updating the rights. Otherwise the client may unintentionally remove
permissions.
5.2. 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").
skipping to change at line 486 skipping to change at line 475
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
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
give information about mailboxes with appropriately restricted ACL's.
For example, a GETACL command on a mailbox for which the user has
insufficient rights should not admit that the mailbox exists, much less
return the mailbox's ACL.
LISTRIGHTS command MUST NOT check that a particular identifier exists,
however it SHOULD recognize special identifiers like "anyone".
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)
to the special identifier "anyone".
7. 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].
Non-terminals referenced but not defined below are as defined by
[IMAP4].
Except as noted otherwise, all alphabetic characters are
case-insensitive. The use of upper or lower case characters to
define token strings is for editorial clarity only. Implementations
MUST accept these strings in a case-insensitive fashion.
rights_capa = "RIGHTS=" new_rights
;; RIGHTS=... capability
new_rights = rights
;; MUST include "t", "e", "x", "m" and "n"
resp-text-code =/ myrights_rspcod
myrights_rspcod = "MYRIGHTS" SP rights
rights = atom
;; MUST NOT contain leading "+" or "-"
;; MUST be treated as case-sensitive
8. References 8. References
8.1. Normative References 8.1. 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, [RFC2086] Myers, J., "IMAP4 ACL extension", RFC 2086, Carnegie Mellon,
January 1997 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 2279, Alis Technologies, January 1998. RFC 3629, Alis Technologies, November 2003.
8.2. Informative References 8.2. Informative References
[ANNOTATE] Gellens, R. and C. Daboo, "IMAP ANNOTATE Extension", [ANNOTATE] Gellens, R. and C. Daboo, "IMAP ANNOTATE Extension",
work in progress, draft-ietf-imapext-annotate-XX.txt work in progress, draft-ietf-imapext-annotate-XX.txt
9. Aknowledgement 9. Acknowledgment
This document is a revision of the RFC 2086 written by John G. Myers. This document is an update to the RFC 2086 written by John G. Myers.
Editor appreciates comments received from Mark Crispin, Chris Newman, Editor appreciates comments received from Mark Crispin, Chris Newman,
Cyrus Daboo, John G. Myers, Steve Hole, Curtis King, Lyndon Nerenberg, Cyrus Daboo, John G. Myers, Steve Hole, Curtis King, Lyndon Nerenberg,
Larry Greenfield, Robert Siemborski, Vladimir Butenko, Dave Cridland, Larry Greenfield, Robert Siemborski, Vladimir Butenko, Dave Cridland,
Harrie Hazewinkel and other participants of the IMAPEXT working group. Harrie Hazewinkel, Philip Guenther, Brian Candler and other participants
of the IMAPEXT working group.
10. Editor's Address 10. 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 11. IPR Disclosure Acknowledgement
skipping to change at line 580 skipping to change at line 627
Acknowledgement Acknowledgement
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 "e" right. EXPUNGE is controlled by the "e" right.
3. Clarified that RENAME requires "c" right for the new parent and "x" 3. Clarified that RENAME requires the "c" right for the new parent and
right for the old name. the "x" right for the old name.
4. Added "t" right that controls STORE \Deleted. Redefined "d" to be a 4. Added the "t" right that controls STORE \Deleted. Redefined the "d"
macro for "e", "x" and "t". right to be a macro for "e", "x" and "t".
5. Specified that "a" right also controls DELETEACL. 5. Specified that the "a" right also controls DELETEACL.
6. Specified that "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 same rights as MYRIGHTS. 8. LISTRIGHTS requires the "a" right on the mailbox (same as SETACL).
9. Deleted "PARTIAL", this is a deprecated feature of RFC1730. 9. Deleted "PARTIAL", this is a deprecated feature of RFC1730.
10. Specified that "w" controls setting flags other than \Seen and 10. Specified that the "w" right controls setting flags other than \Seen
\Deleted on APPEND. Same for "s" and "t" flags. and \Deleted on APPEND. Also specified that the "s" right controls
the \Seen flag and that the "t" right controls the \Deleted flag.
11. SUBSCRIBE is NOT allowed with "r" right. 11. SUBSCRIBE is NOT allowed with the "r" right.
12. Specified that "l" controls SUBSCRIBE. 12. Specified that the "l" right controls SUBSCRIBE.
13. GETACL is NOT allowed with "r" right, even though there are several 13. GETACL is NOT allowed with the "r" right, even though there are
implementations that allows that. If a user only has "r" right, several implementations that allows that. If a user only has "r"
GETACL can disclose information about identifiers existing on the right, GETACL can disclose information about identifiers existing
mail system. on the mail system.
14. Added new section that describes which rights are required and/or 14. 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 15. Added mail client security considerations when dealing with special
identifier "anyone". identifier "anyone".
16. Clarified that negative rights are not the same as DELETEACL. 16. 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 17. Added note that a server can modify an ACL for any identifier(s) as a
side effect of performing SETACL/DELETEACL. Also specified that side effect of performing SETACL/DELETEACL. Also specified that
the server MUST send untagged ACL response if it does that. the server MUST send untagged ACL response if it does that.
<<Updated command definition to include optional ACL untagged response.>>
18. Added section about mapping of ACL rights to READ-WRITE and READ-ONLY 18. Added section about mapping of ACL rights to READ-WRITE and READ-ONLY
response codes. response codes.
19. Added "Compatibility with RFC 2086" section. 19. Added "Compatibility with RFC 2086" section.
20. Added "Implementation Notes" section. 20. Added "Implementation Notes" section.
21. Updated "References" 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.
24. Added MYRIGHTS response code.
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 replaces "d" right with 3 new different rights "x", "t" This document splits the "d" right into 3 new different rights "x", "t"
and "e". The server should implement one of the following two and "e". The "d" right remains for backwards-compatibility but it is a
approaches to handle "d" and the new rights that have replaced it. virtual right. See section 3 for details. The server should imple
ment
one of the following two approaches to handle the "d" right and the new
rights that have replaced<<>> it.
a). Tie "x", "t" and "e" together - almost no changes a). Tie "x", "t" and "e" together - almost no changes.
b). Implement separate "x", "t" and "e". Return "d" right in a LIST b). Implement separate "x", "t" and "e". Return "d" right in a
response containing ACL information when all three of "x", "t" MYRIGHTS response/response code and an ACL response containing ACL
and "e" are granted. information when all three of "x", "t" and "e" are granted.
Additional work required to implement the RIGHTS extension when RFC 2086
is already implemented:
1). Send the MYRIGHTS untagged response on a successful SELECT/EXAMINE.
Also check Sections 7.1 and 7.2, as well as the appendix A to see Also check Sections 7.1 and 7.2, 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 4.
 End of changes. 

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