One document matched: draft-martin-managesieve-12.txt
Differences from draft-martin-managesieve-11.txt
Sieve Working Group A. Melnikov, Ed.
Internet-Draft Isode Limited
Intended status: Standards Track T. Martin
Expires: March 17, 2009 BeThereBeSquare Inc.
September 13, 2008
A Protocol for Remotely Managing Sieve Scripts
draft-martin-managesieve-12
Status of this Memo
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Abstract
Sieve scripts allow users to filter incoming email. Message stores
are commonly sealed servers so users cannot log into them, yet users
must be able to update their scripts on them. This document
describes a protocol "ManageSieve" for securely managing Sieve
scripts on a remote server. This protocol allows a user to have
multiple scripts, and also alerts a user to syntactically flawed
scripts.
Changes since draft-martin-managesieve-09
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o TBD.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Conventions used in this document . . . . . . . . . . . . 4
1.2. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3. Response Codes . . . . . . . . . . . . . . . . . . . . . . 4
1.4. Active Script . . . . . . . . . . . . . . . . . . . . . . 7
1.5. Quotas . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.6. Script Names . . . . . . . . . . . . . . . . . . . . . . . 7
1.7. Capabilities . . . . . . . . . . . . . . . . . . . . . . . 8
1.8. Link Level . . . . . . . . . . . . . . . . . . . . . . . . 9
2. Commands . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.1. AUTHENTICATE Command . . . . . . . . . . . . . . . . . . . 10
2.1.1. Use of SASL PLAIN mechanism over TLS . . . . . . . . . . . 14
2.2. STARTTLS Command . . . . . . . . . . . . . . . . . . . . . 15
2.2.1. Server Identity Check . . . . . . . . . . . . . . . . . . 15
2.3. LOGOUT Command . . . . . . . . . . . . . . . . . . . . . . 18
2.4. CAPABILITY Command . . . . . . . . . . . . . . . . . . . . 18
2.5. HAVESPACE Command . . . . . . . . . . . . . . . . . . . . 18
2.6. PUTSCRIPT Command . . . . . . . . . . . . . . . . . . . . 19
2.7. LISTSCRIPTS Command . . . . . . . . . . . . . . . . . . . 20
2.8. SETACTIVE Command . . . . . . . . . . . . . . . . . . . . 21
2.9. GETSCRIPT Command . . . . . . . . . . . . . . . . . . . . 21
2.10. DELETESCRIPT Command . . . . . . . . . . . . . . . . . . . 22
2.11. Recommended extensions . . . . . . . . . . . . . . . . . . 22
2.11.1. RENAMESCRIPT Command . . . . . . . . . . . . . . . . . . . 23
2.11.2. NOOP Command . . . . . . . . . . . . . . . . . . . . . . . 24
2.11.3. UNAUTHENTICATE Command . . . . . . . . . . . . . . . . . . 24
3. Sieve URL Scheme . . . . . . . . . . . . . . . . . . . . . 24
4. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . 26
5. Security Considerations . . . . . . . . . . . . . . . . . 31
6. IANA Considerations . . . . . . . . . . . . . . . . . . . 32
6.1. Manage Sieve Capability Registration Template . . . . . . 32
6.2. Registration of Initial Manage Sieve capabilities . . . . 33
6.3. Manage Sieve Response Code Registration Template . . . . . 35
6.4. Registration of Initial Manage Sieve Response Codes . . . 35
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . 38
8. References . . . . . . . . . . . . . . . . . . . . . . . . 38
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8.1. Normative References . . . . . . . . . . . . . . . . . . . 38
8.2. Informative References . . . . . . . . . . . . . . . . . . 40
Authors' Addresses . . . . . . . . . . . . . . . . . . . . 40
Intellectual Property and Copyright Statements . . . . . . 42
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1. Introduction
1.1. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [KEYWORDS].
In examples, "C:" and "S:" indicate lines sent by the client and
server respectively. Line breaks that do not start a new "C:" or
"S:" exist for editorial reasons.
1.2. Syntax
This a line oriented protocol much like [IMAP4rev1] or [ACAP]. There
are three data types: atoms, numbers and strings. Strings may be
quoted or literal. See [ACAP] for detailed descriptions of these
types.
Each command consists of an atom (the command name) followed by zero
or more strings and numbers terminated by CRLF.
All client queries are replied to with either an OK, NO, or BYE
response. Each response may be followed by a response code (see
Section 1.3) and by a string consisting of human readable text in the
local language, encoded in [UTF-8]. The contents of the string
SHOULD be shown to the user and implementations MUST NOT attempt to
parse the message for meaning.
The BYE response SHOULD be used if the server wishes to close the
connection. A server may wish to do this because the client was idle
for too long or there were too many failed authentication attempts.
This response can be issued at any time and should be immediately
followed by a server hang-up of the connection. If a server has an
inactivity timeout resulting in client autologout it MUST be no less
than 30 minutes after successful authentication. The inactivity
timeout MAY be less before authentication.
1.3. Response Codes
An OK, NO, or BYE response from the server MAY contain a response
code to describe the event in a more detailed machine parsable
fashion. A response code consists of data inside parentheses in the
form of an atom, possibly followed by a space and arguments.
Response codes are defined when there is a specific action that a
client can take based upon the additional information. In order to
support future extension, the response code is represented as a
slash-separated (Solidus, %x2F) hierarchy with each level of
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hierarchy representing increasing detail about the error. Response
codes MUST NOT start with the Solidus character. Clients MUST
tolerate additional hierarchical response code detail which they
don't understand. For example, if the client supports the "QUOTA"
response code, but doesn't understand the "QUOTA/MAXSCRIPTS" response
code, it should treat "QUOTA/MAXSCRIPTS" as "QUOTA".
Client implementations MUST tolerate (ignore) response codes that
they do not recognize.
The currently defined response codes are:
AUTH-TOO-WEAK
This response code is returned in the NO response from an
AUTHENTICATE command. It indicates that site security policy forbids
the use of the requested mechanism for the specified authentication
identity.
ENCRYPT-NEEDED
This response code is returned in the NO response from an
AUTHENTICATE command. It indicates that site security policy
requires the use of a strong encryption mechanism for the specified
authentication identity and mechanism.
QUOTA
If this response code is returned in the NO/BYE response, it means
that the command would have placed the user above the site-defined
quota constraints. If this response code is returned in the OK
response, it can mean that the user's storage is near its quota, or
it can mean that the account exceeded its quota but that that
condition is being allowed by the server (the server supports so
called "soft quotas").
REFERRAL
This response code may be returned with a BYE result from any
command, and includes a mandatory parameter that indicates what
server to access to manage this user's sieve scripts. The server
will be specified by a Sieve URL (see Section 3). The scriptname
portion of the URL MUST NOT be specified. The client should
authenticate to the specified server and use it for all further
commands in the current session.
SASL
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This response code can occur in the OK response to a successful
AUTHENTICATE command and includes the optional final server response
data from the server as specified by [SASL].
TRANSITION-NEEDED
This response code occurs in a NO response of an AUTHENTICATE
command. It indicates that the user name is valid, but the entry in
the authentication database needs to be updated in order to permit
authentication with the specified mechanism. This is typically done
by establishing a secure channel using TLS, verifying server identity
as specified in Section 2.2.1, and finally authenticating once using
the [PLAIN] authentication mechanism. The selected mechanism SHOULD
then work for authentications in subsequent sessions.
This condition can happen if a user has an entry in a system
authentication database such as Unix /etc/passwd, but does not have
credentials suitable for use by the specified mechanism.
TRYLATER
A command failed due to a temporary server failure. The client MAY
continue using local information and try the command later. This
response code only makes sense when returned in a NO/BYE response.
ACTIVE
A command failed because it is not allowed on the active script. For
example DELETESCRIPT on the active script. This response code only
makes sense when returned in a NO/BYE response.
NONEXISTENT
A command failed because the references script name doesn't exist.
This response code only makes sense when returned in a NO/BYE
response.
ALREADYEXISTS
A command failed because the references script name already exists.
This response code only makes sense when returned in a NO/BYE
response.
TAG
This response code name is followed by a string specified in the
command. See Section 2.11.2 for a possible use case.
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1.4. Active Script
A user may have multiple Sieve scripts on the server, yet only one
script may be used for filtering of incoming messages. This is the
active script. Users may have zero or one active scripts and MUST
use the SETACTIVE command described below for changing the active
script or disabling Sieve processing. For example, a user may have
an everyday script they normally use and a special script they use
when they go on vacation. Users can change which script is being
used without having to download and upload a script stored somewhere
else.
1.5. Quotas
Servers SHOULD impose quotas to prevent malicious users from
overflowing available storage. If a command would place a user over
a quota setting, servers that impose such quotas MUST reply with a NO
response containing the QUOTA response code. Client implementations
MUST be able to handle commands failing because of quota
restrictions.
1.6. Script Names
A Sieve script name is a sequence of Unicode characters encoded in
UTF-8 [UTF-8]. A script name MUST comply with Net-Unicode Definition
(Sectio 2 of [NET-UNICODE]), with the following additional
restrictions:
o 0000-001F; [CONTROL CHARACTERS]
o 007F; DELETE
o 0080-009F; [CONTROL CHARACTERS]
o 2028; LINE SEPARATOR
o 2029; PARAGRAPH SEPARATOR
Sieve script names MUST be at least one octet (and hense Unicode
character) long. Zero octets script name has a special meaning (see
Section 2.8). Servers MUST allow names of up to 128 Unicode
characters in length (which can take up to 512 bytes when encoded in
UTF-8, not counting the terminating NUL), and MAY allow longer names.
A server that receives a script name longer than its internal limit
MUST rejects the corresponding operation, in particular it MUST NOT
truncate the script name.
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1.7. Capabilities
Server capabilities are sent automatically by the server upon a
client connection, or after successful STARTTLS and AUTHENTICATE
(which establishes a SASL security layer) commands. Capabilities may
change immediately after a successfully completed STARTTLS command
and/or immediately after a successfully completed AUTHENTICATE
command. Capabilities MUST remain static at all other times.
Clients MAY request the capabilities at a later time by issuing the
CAPABILITY command described later. The capabilities consist of a
series of lines each with one or two strings. The first string is
the name of the capability, which is case-insensitive. The second
optional string is the value associated with that capability. Order
of capabilities is arbitrary, but each capability name can appear at
most once.
The following capabilities are defined in this document:
IMPLEMENTATION - Name of implementation and version.
SASL - List of SASL mechanisms supported by the server, each
separated by a space. This list can be empty if and only if STARTTLS
is also advertised. This means that the client must negotiate TLS
encryption with STARTTLS first, at which point the SASL capability
will list a non empty list of SASL mechanisms.
SIEVE - List of space separated Sieve extensions (as listed in Sieve
"require" action [SIEVE]) supported by the Sieve engine.
STARTTLS - If TLS [TLS] is supported by this implementation. Before
advertising this capability a server MUST verify to the best of its
ability that TLS can be successfully negotiated by a client with
common cipher suites. Specifically, a server should verify that a
server certificate has be installed and that the TLS subsystem has
successfully initialized.
NOTIFY - A space separated list of URI schema parts for supported
notification methods. This capability MUST be specified if the Sieve
implementation supports the "enotify" extension [NOTIFY].
LANGUAGE - The language (<Language-Tag> from [RFC4646]) currently
used for human readable error messages. If this capability is not
returned, the "i-default" [RFC2277] language is assumed. Note that
the current language MAY be per-user configurable (i.e. it MAY change
after authentication).
Section 2.11 defines some additional ManageSieve extensions and their
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respective capabilities.
A server implementation MUST return SIEVE and IMPLEMENTATION
capabilities.
A client implementation MUST ignore any listed capabilities that it
does not understand.
Example:
S: "IMPlemENTATION" "Example1 ManageSieved v001"
S: "SASl" "DIGEST-MD5 GSSAPI"
S: "SIeVE" "fileinto vacation"
S: "StaRTTLS"
S: "NOTIFY" "xmpp mailto"
S: OK
1.8. Link Level
The ManageSieve protocol assumes a reliable data stream such as that
provided by TCP. When TCP is used, a ManageSieve server typically
listens on port 2000. [[anchor6: IANA registration of port 2000 is
pending.]]
Before opening the TCP connection, the ManageSieve client first MUST
resolve the Domain Name System (DNS) hostname associated with the
receiving entity and determine the appropriate TCP port for
communication with the receiving entity. The process is as follows:
1. Attempt to resolve the hostname using a [DNS-SRV] Service of
"sieve" and a Proto of "tcp" for the target domain (e.g.
"example.net"), resulting in resource records such as
"_sieve._tcp.example.net.". The result of the SRV lookup, if
successful, will be one or more combinations of a port and
hostname; the ManageSieve client MUST resolve the returned
hostnames to IPv4/IPv6 addresses according to returned SRV record
weight. IP addresses from the first successfully resolved
hostname (with the corresponding port number returned by SRV
lookup) are used to connect to the server. If connection using
one of the IP addresses fails, the next resolved IP address is
used to connect. If connection to all resolved IP addresses
fails, then the resolution/connect is repeated for the next
hostname returned by SRV lookup.
2. If the SRV lookup fails, the fallback SHOULD be a normal IPv4 or
IPv6 address record resolution to determine the IP address, where
the port used is the default ManageSieve port of 2000.
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2. Commands
This section and its subsections describes valid ManageSieve
commands. Upon initial connection to the server the client's session
is in non-authenticated state. Prior to successful authentication
only the AUTHENTICATE, CAPABILITY, STARTTLS, LOGOUT and NOOP (see
Section 2.11.2) commands are valid. ManageSieve extensions MAY
define other commands which are valid in non-authenticated state.
Servers MUST reject all other commands with a NO response. Clients
may pipeline commands (send more than one command at a time without
waiting for completion of the first command ). However, a group of
commands sent together MUST NOT have an AUTHENTICATE (*), a STARTTLS
or a HAVESPACE command anywhere but the last command in the list.
(*) - The only exception to this rule is when the AUTHENTICATE
command contains an initial response for a SASL mechanism that allows
clients to send data first, the mechanism is known to complete in one
round-trip and the mechanism doesn't negotiate a SASL security layer.
Two examples of such SASL mechanisms are PLAIN [PLAIN] and EXTERNAL
[SASL].
2.1. AUTHENTICATE Command
Arguments: String - mechanism
String - initial data (optional)
The AUTHENTICATE command indicates a SASL [SASL] authentication
mechanism to the server. If the server supports the requested
authentication mechanism, it performs an authentication protocol
exchange to identify and authenticate the user. Optionally, it also
negotiates a security layer for subsequent protocol interactions. If
the requested authentication mechanism is not supported, the server
rejects the AUTHENTICATE command by sending the NO response.
The authentication protocol exchange consists of a series of server
challenges and client responses that are specific to the selected
authentication mechanism. A server challenge consists of a string
(quoted or literal) followed by a CRLF. The contents of the string
is a base-64 encoding [BASE64] of the SASL data. A client response
consists of a string (quoted or literal) with the base-64 encoding of
the SASL data followed by a CRLF. If the client wishes to cancel the
authentication exchange, it issues a string containing a single "*".
If the server receives such a response, it MUST reject the
AUTHENTICATE command by sending an NO reply.
Note that an empty challenge/response is sent as an empty string. If
the mechanism dictates that the final response is sent by the server
this data MAY be placed within the data portion of the SASL response
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code to save a round trip.
The optional initial-response argument to the AUTHENTICATE command is
used to save a round trip when using authentication mechanisms that
are defined to send no data in the initial challenge. When the
initial-response argument is used with such a mechanism, the initial
empty challenge is not sent to the client and the server uses the
data in the initial-response argument as if it were sent in response
to the empty challenge. If the initial-response argument to the
AUTHENTICATE command is used with a mechanism that sends data in the
initial challenge, the server MUST reject the AUTHENTICATE command by
sending the NO response.
The service name specified by this protocol's profile of SASL is
"sieve".
Reauthentication is not supported by ManageSieve protocol's profile
of SASL. I.e. after a successfully completed AUTHENTICATE command,
no more AUTHENTICATE commands may be issued in the same session.
After a successful AUTHENTICATE command completes, a server MUST
reject any further AUTHENTICATE commands with a NO reply. However
note that a server may implement UNAUTHENTICATE extension described
in Section 2.11.3.
If a security layer is negotiated through the SASL authentication
exchange, it takes effect immediately following the CRLF that
concludes the successful authentication exchange for the client, and
the CRLF of the OK response for the server.
When a security layer takes effect, the ManageSieve protocol is reset
to the initial state (the state in ManageSieve after a client has
connected to the server). The server MUST discard any knowledge
obtained from the client which was not obtained from the SASL (or
TLS) negotiation itself. Likewise, the client MUST discard any
knowledge obtained from the server, such as the list of ManageSieve
extensions, which was not obtained from the SASL (or TLS) negotiation
itself. (Note that a client MAY compare the advertised SASL
mechanisms before and after authentication in order to detect an
active down-negotiation attack. See below.)
Once a SASL security layer is established, the server MUST re-issue
the capability results, followed by an OK response. This is
necessary to protect against man-in-the-middle attacks which alter
the capabilities list prior to SASL negotiation. The capability
results MUST include all SASL mechanisms the server was capable of
negotiating with that client. This is done in order to allow client
to detect active down-negotiation attack.
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When both [TLS] and SASL security layers are in effect, the TLS
encoding MUST be applied (when sending data) after the SASL encoding,
regardless of the order in which the layers were negotiated.
Server implementations SHOULD support SASL proxy authentication so
that an administrator can administer a user's scripts. Proxy
authentication is when a user authenticates as herself/himself but
requests the server to act (authorize) as another user.
The authorization identity generated by this [SASL] exchange is a
"simple username" (in the sense defined in [SASLprep]), and both
client and server MUST use the [SASLprep] profile of the [StringPrep]
algorithm to prepare these names for transmission or comparison. If
preparation of the authorization identity fails or results in an
empty string (unless it was transmitted as the empty string), the
server MUST fail the authentication.
If an AUTHENTICATE command fails with a NO response, the client MAY
try another authentication mechanism by issuing another AUTHENTICATE
command. In other words, the client may request authentication types
in decreasing order of preference.
Note that a failed (NO) response to the AUTHENTICATE command may
contain one of the following response codes: AUTH-TOO-WEAK, ENCRYPT-
NEEDED or TRANSITION-NEEDED. See Section 1.3 for detailed
description of the relevant conditions.
To ensure interoperability, client and server implementations of this
extension MUST implement the [SCRAM] SASL mechanism.
Implementations MAY advertise the ANONYMOUS SASL mechanism
[SASL-ANON]. This indicates that the server supports ANONYMOUS SIEVE
script syntax verification. Only the CAPABILITY, PUTSCRIPT and
LOGOUT commands are available to the anonymous user. All other
commands MUST give NO responses. Furthermore the PUTSCRIPT command
MUST NOT persistently store any data. In this mode a positive
response to the PUTSCRIPT command indicates that the given script
does not have any syntax errors.
Examples (Note that long lines are folded for readability and are not
part of protocol exchange):
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S: "IMPLEMENTATION" "Example1 ManageSieved v001"
S: "SASL" "DIGEST-MD5 GSSAPI"
S: "SIEVE" "fileinto vacation"
S: "STARTTLS"
S: OK
C: Authenticate "DIGEST-MD5"
S: "cmVhbG09ImVsd29vZC5pbm5vc29mdC5jb20iLG5vbmNlPSJPQTZNRzl0
RVFHbTJoaCIscW9wPSJhdXRoIixhbGdvcml0aG09bWQ1LXNlc3MsY2hh
cnNldD11dGYtOA=="
C: "Y2hhcnNldD11dGYtOCx1c2VybmFtZT0iY2hyaXMiLHJlYWxtPSJlbHdvb2
QuaW5ub3NvZnQuY29tIixub25jZT0iT0E2TUc5dEVRR20yaGgiLG5jPTAw
MDAwMDAxLGNub25jZT0iT0E2TUhYaDZWcVRyUmsiLGRpZ2VzdC11cmk9Im
ltYXAvZWx3b29kLmlubm9zb2Z0LmNvbSIscmVzcG9uc2U9ZDM4OGRhZDkw
ZDRiYmQ3NjBhMTUyMzIxZjIxNDNhZjcscW9wPWF1dGg="
S: OK (SASL "cnNwYXV0aD1lYTQwZjYwMzM1YzQyN2I1NTI3Yjg0ZGJhYmNkZ
mZmZA==")
A slightly different variant of the same authentication exchange:
S: "IMPLEMENTATION" "Example1 ManageSieved v001"
S: "SASL" "DIGEST-MD5 GSSAPI"
S: "SIEVE" "fileinto vacation"
S: "STARTTLS"
S: OK
C: Authenticate "DIGEST-MD5"
S: {128}
S: cmVhbG09ImVsd29vZC5pbm5vc29mdC5jb20iLG5vbmNlPSJPQTZNRzl0
RVFHbTJoaCIscW9wPSJhdXRoIixhbGdvcml0aG09bWQ1LXNlc3MsY2hh
cnNldD11dGYtOA==
C: {276+}
C: Y2hhcnNldD11dGYtOCx1c2VybmFtZT0iY2hyaXMiLHJlYWxtPSJlbHdvb2
QuaW5ub3NvZnQuY29tIixub25jZT0iT0E2TUc5dEVRR20yaGgiLG5jPTAw
MDAwMDAxLGNub25jZT0iT0E2TUhYaDZWcVRyUmsiLGRpZ2VzdC11cmk9Im
ltYXAvZWx3b29kLmlubm9zb2Z0LmNvbSIscmVzcG9uc2U9ZDM4OGRhZDkw
ZDRiYmQ3NjBhMTUyMzIxZjIxNDNhZjcscW9wPWF1dGg="
S: {56}
S: cnNwYXV0aD1lYTQwZjYwMzM1YzQyN2I1NTI3Yjg0ZGJhYmNkZmZmZA==
C: ""
S: OK
Another example demonstrating use of SASL PLAIN mechanism under TLS.
This example also demonstrate use of SASL "initial response" (the
second parameter to the Authenticate command):
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S: "IMPLEMENTATION" "Example1 ManageSieved v001"
S: "SASL" ""
S: "SIEVE" "fileinto vacation"
S: "STARTTLS"
S: OK
C: STARTTLS
S: OK
<TLS negotiation, further commands are under TLS layer>
S: "IMPLEMENTATION" "Example1 ManageSieved v001"
S: "SASL" "PLAIN"
S: "SIEVE" "fileinto vacation"
S: OK
C: Authenticate "PLAIN" "QJIrweAPyo6Q1T9xu"
S: NO
C: Authenticate "PLAIN" "QJIrweAPyo6Q1T9xz"
S: NO
C: Authenticate "PLAIN" "QJIrweAPyo6Q1T9xy"
S: BYE "Too many failed authentication attempts"
<Server closes connection>
The following example demonstrates use of SASL "initial response".
It also demonstrates that an empty response can be sent as a literal:
C: AUTHENTICATE "GSSAPI" {1488+}
C: YIIE[...1480 octets here ...]dA==
S: {208}
S: YIGZBgkqhkiG9xIBAgICAG+BiTCBhqADAgEFoQMCAQ+iejB4oAMCARKic
[...114 octets here ...]
/yzpAy9p+Y0LanLskOTvMc0MnjgAa4YEr3eJ6
C: {0+}
C:
S: {44}
S: BQQF/wAMAAwAAAAAYRGFAo6W0vIHti8i1UXODgEAEAA=
C: {44+}
C: BQQE/wAMAAwAAAAAIsT1iv9UkZApw471iXt6cwEAAAE=
S: OK
2.1.1. Use of SASL PLAIN mechanism over TLS
This section is normative for ManageSieve client implementations that
support SASL [PLAIN] over [TLS].
If a ManageSieve client is willing to use SASL PLAIN over TLS to
authenticate to the ManageSieve server, the client MUST verify the
server identity (see Section 2.2.1). If the server identity can't be
verified (e.g. the server has not provided any certificate, or if the
certificate verification fails) the client MUST NOT attempt to
authenticate using the SASL PLAIN mechanism.
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2.2. STARTTLS Command
Support for STARTTLS command in servers is optional. Its
availability is advertised with "STARTTLS" capability as described in
Section 1.7.
The STARTTLS command requests commencement of a TLS [TLS]
negotiation. The negotiation begins immediately after the CRLF in
the OK response. After a client issues a STARTTLS command, it MUST
NOT issue further commands until a server response is seen and the
TLS negotiation is complete.
The STARTTLS command is only valid in non-authenticated state. The
server remains in non-authenticated state, even if client credentials
are supplied during the TLS negotiation. The SASL [SASL] EXTERNAL
mechanism MAY be used to authenticate once TLS client credentials are
successfully exchanged, but servers supporting the STARTTLS command
are not required to support the EXTERNAL mechanism.
After the TLS layer is established, the server MUST re-issue the
capability results, followed by an OK response. This is necessary to
protect against man-in-the-middle attacks which alter the
capabilities list prior to STARTTLS. This capability result MUST NOT
include the STARTTLS capability.
The client MUST discard cached capability information and replace it
with the new information. The server MAY advertise different
capabilities after STARTTLS.
Example:
C: StartTls
S: oK
<TLS negotiation, further commands are under TLS layer>
S: "IMPLEMENTATION" "Example1 ManageSieved v001"
S: "SASL" "PLAIN DIGEST-MD5 GSSAPI"
S: "SIEVE" "fileinto vacation"
S: "LANGUAGE" "fr"
S: ok
2.2.1. Server Identity Check
During the TLS negotiation, the ManageSieve client MUST check its
understanding of the server hostname/IP address against the server's
identity as presented in the server Certificate message, in order to
prevent man-in-the-middle attacks. In this section, the client's
understanding of the server's identity is called the "reference
identity".
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Checking is performed according to the following rules:
o If the reference identity is a hostname:
1. If a subjectAltName extension of the SRVName [X509-SRV],
dNSName [X509] (in that order of preference) type is present
in the server's certificate, than it SHOULD be used as the
source of the server's identity. Matching is performed as
described in Section 2.2.1.1, with the exception that no
wildcard matching is allowed for SRVName type. If the
certificate contains multiple names (e.g., more than one
dNSName field), then a match with any one of the fields is
considered acceptable.
2. The client MAY use other types of subjectAltName for
performing comparison.
3. The server's identity MAY also be verified by comparing the
reference identity to the Common Name (CN) [RFC4519] value in
the leaf Relative Distinguished Name (RDN) of the subjectName
field of the server's certificate. This comparison is
performed using the rules for comparison of DNS names in
Section 2.2.1.1, below, with the exception that no wildcard
matching is allowed. [[anchor8: Chris Newman says that such
prohibition of wildcards doesn't match existing practice.]]
Although the use of the Common Name value is existing
practice, it is deprecated, and Certification Authorities are
encouraged to provide subjectAltName values instead. Note
that the TLS implementation may represent DNs in certificates
according to X.500 or other conventions. For example, some
X.500 implementations order the RDNs in a DN using a left-to-
right (most significant to least significant) convention
instead of LDAP's right- to-left convention.
o When the reference identity is an IP address, the iPAddress
subjectAltName SHOULD be used by the client for comparison. The
comparison is performed as described in Section 2.2.1.2.
o In either case the client MAY map the reference identity to a
different type prior to performing a comparison. Mappings may be
performed for all available subjectAltName types to which the
reference identity can be mapped; however, the reference identity
should only be mapped to types for which the mapping is either
inherently secure (e.g., extracting the DNS hostname from a URI)
or for which the mapping is performed in a secure manner (e.g.,
using DNSSEC, or using user- or admin-configured host-to-address/
address-to-host lookup tables).
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If the server identity check fails, user-oriented clients SHOULD
either notify the user (clients MAY give the user the opportunity to
continue with the ManageSieve session in this case) or close the
transport connection and indicate that the server's identity is
suspect. Automated clients SHOULD return or log an error indicating
that the server's identity is suspect and/or SHOULD close the
transport connection. Automated clients MAY provide a configuration
setting that disables this check, but MUST provide a setting which
enables it.
Beyond the server identity check described in this section, clients
should be prepared to do further checking to ensure that the server
is authorized to provide the service it is requested to provide. The
client may need to make use of local policy information in making
this determination.
2.2.1.1. Comparison of DNS Names
If the reference identity is an internationalized domain name,
conforming implementations MUST convert it to the ASCII Compatible
Encoding (ACE) format as specified in Section 4 of RFC 3490 [RFC3490]
before comparison with subjectAltName values of type dNSName.
Specifically, conforming implementations MUST perform the conversion
operation specified in Section 4 of [RFC3490] as follows:
o in step 1, the domain name SHALL be considered a "stored string";
o in step 3, set the flag called "UseSTD3ASCIIRules";
o in step 4, process each label with the "ToASCII" operation; and
o in step 5, change all label separators to U+002E (full stop).
After performing the "to-ASCII" conversion, the DNS labels and names
MUST be compared for equality according to the rules specified in
Section 3 of [RFC3490], i.e. once all label separators are replaced
with U+002E (dot) they are compared in the case-insensitive manner.
The '*' (ASCII 42) wildcard character is allowed in subjectAltName
values of type dNSName, and then only as the left-most (least
significant) DNS label in that value. This wildcard matches any
left-most DNS label in the server name. That is, the subject
*.example.com matches the server names a.example.com and
b.example.com, but does not match example.com or a.b.example.com.
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2.2.1.2. Comparison of IP Addresses
When the reference identity is an IP address, the identity MUST be
converted to the "network byte order" octet string representation
[RFC791][RFC2460]. For IP Version 4, as specified in RFC 791, the
octet string will contain exactly four octets. For IP Version 6, as
specified in RFC 2460, the octet string will contain exactly sixteen
octets. This octet string is then compared against subjectAltName
values of type iPAddress. A match occurs if the reference identity
octet string and value octet strings are identical.
2.2.1.3. Comparison of Other subjectName Types
Client implementations MAY support matching against subjectAltName
values of other types as described in other documents.
2.3. LOGOUT Command
The client sends the LOGOUT command when it is finished with a
connection and wishes to terminate it. The server MUST reply with an
OK response and terminate the connection. The server MUST ignore
commands issued by the client after the LOGOUT command.
Example:
C: Logout
S: Ok
<connection terminated>
2.4. CAPABILITY Command
The CAPABILITY command requests the server capabilities as described
earlier in this document. It has no parameters.
Example:
C: CAPABILITY
S: "IMPLEMENTATION" "Example1 ManageSieved v001"
S: "SASL" "PLAIN KERBEROS_V4 GSSAPI"
S: "SIEVE" "fileinto vacation"
S: "STARTTLS"
S: OK
2.5. HAVESPACE Command
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Arguments: String - name
Number - script size
The HAVESPACE command is used to query the server for available
space. Clients specify the name they wish to save the script as and
its size in octets. Servers respond with an NO if storing a script
with that name and size would fail or OK otherwise. Clients SHOULD
issue this command before attempting to place a script on the server.
Note that the OK response from the HAVESPACE command does not
constitute a guarantee of success as server disk space conditions
could change between the client issuing the HAVESPACE and the client
issuing the PUTSCRIPT commands. A QUOTA response code (see
Section 1.3) remains a possible (albeit unlikely) response to a
subsequent PUTSCRIPT with the same name and size.
Example:
C: HAVESPACE "myscript" 999999
S: NO (QUOTA) "Quota exceeded"
C: HAVESPACE "foobar" 435
S: OK
2.6. PUTSCRIPT Command
Arguments: String - Script name
String - Script content
The PUTSCRIPT command is used by the client to submit a Sieve script
to the server.
If the script already exists, upon success the old script will be
overwritten. The old script MUST NOT be overwritten if PUTSCRIPT
fails in any way. A script of zero length SHOULD be disallowed.
This command places the script on the server. It does not affect
whether the script is processed on incoming mail, unless it replaces
the script which is already active. The SETACTIVE command is used to
mark a script as active.
When submitting large scripts clients SHOULD use the HAVESPACE
command beforehand to query if the server is willing to accept a
script of that size.
The server MUST check the submitted script for syntactic validity,
which includes checking that all Sieve extensions mentioned in Sieve
script "require" statement(s) are supported by the Sieve interpreter.
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If the script fails this test the server MUST reply with a NO
response. Any script that fails the validity test MUST NOT be stored
on the server. The message given with a NO response MUST be human
readable and SHOULD contain a specific error message giving the line
number of the first error. Implementors should strive to produce
helpful error messages similar to those given by programming language
compilers. Client implementations should note that this may be a
multiline literal string with more than one error message separated
by CRLFs. The human readable message is in the language returned in
the latest LANGUAGE capability (or in "i-default", see Section 1.7),
encoded in UTF-8 [UTF-8].
Example:
C: Putscript "foo" {31+}
C: #comment
C: InvalidSieveCommand
C:
S: NO "line 2: Syntax error"
C: Putscript "mysievescript" {110+}
C: require ["fileinto"];
C:
C: if envelope :contains "to" "tmartin+sent" {
C: fileinto "INBOX.sent";
C: }
S: OK
2.7. LISTSCRIPTS Command
This command lists the scripts the user has on the server. Upon
success a list of CRLF separated script names (each represented as a
quoted or literal string) is returned followed by an OK response. If
there exists an active script the atom ACTIVE is appended to the
corresponding script name. The atom ACTIVE MUST NOT appear on more
than one response line.
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Example:
C: Listscripts
S: "summer_script"
S: "vacation_script"
S: {13}
S: clever"script
S: "main_script" ACTIVE
S: OK
C: listscripts
S: "summer_script"
S: "main_script" active
S: OK
2.8. SETACTIVE Command
Arguments: String - script name
This command sets a script active. If the script name is the empty
string (i.e. "") then any active script is disabled. Disabling an
active script when there is no script active is not an error and MUST
result in OK reply.
If the script does not exist on the server then the server MUST reply
with a NO response. Such reply SHOULD contain the NONEXISTENT
response code.
Examples:
C: Setactive "vacationscript"
S: Ok
C: Setactive ""
S: Ok
C: Setactive "baz"
S: No (NONEXISTENT) "There is no script by that name"
C: Setactive "baz"
S: No (NONEXISTENT) {31}
S: There is no script by that name
2.9. GETSCRIPT Command
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Arguments: String - script name
This command gets the contents of the specified script. If the
script does not exist the server MUST reply with a NO response. Such
reply SHOULD contain the NONEXISTENT response code.
Upon success a string with the contents of the script is returned
followed by a OK response.
Example:
C: Getscript "myscript"
S: {54}
S: #this is my wonderful script
S: reject "I reject all";
S:
S: OK
2.10. DELETESCRIPT Command
Arguments: String - script name
This command is used to delete a user's Sieve script. Servers MUST
reply with a NO response if the script does not exist. Such
responses SHOULD include the NONEXISTENT response code.
The server MUST NOT allow the client to delete an active script, so
the server MUST reply with a NO response if attempted. Such response
SHOULD contain the ACTIVE response code. If a client wishes to
delete an active script it should use the SETACTIVE command to
disable the script first.
Example:
C: Deletescript "foo"
S: Ok
C: Deletescript "baz"
S: No (ACTIVE) "You may not delete an active script"
2.11. Recommended extensions
This Section defines several extensions support for which is
RECOMMENDED.
The RENAME extension (advertised as the "RENAME" capability with no
parameters) defines a new RENAMESCRIPT command.
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The NOOP extension (advertised as the "NOOP" capability with no
parameters) defines a new NOOP command.
The UNAUTHENTICATE extension (advertised as the "UNAUTHENTICATE"
capability with no parameters) defines a new UNAUTHENTICATE command,
which allows a client to return the server to non-authenticated
state.
2.11.1. RENAMESCRIPT Command
Arguments: String - Old Script name
String - New Script name
This command is used to rename a user's Sieve script. Servers MUST
reply with a NO response if the old script does not exist (in which
case the NONEXISTENT response code SHOULD be included), or a script
with the new name already exists (in which case the ALREADYEXISTS
response code SHOULD be included). Renaming the active script is
allowed, the renamed script remains active.
Example:
C: Renamescript "foo" "bar"
S: Ok
C: Renamescript "baz" "bar"
S: No "bar already exists"
If the server doesn't support the RENAMESCRIPT command, the client
can emulate it by performing the following steps:
1. List available scripts with LISTSCRIPTS. If the script with the
new script name exists, then the client should ask the user
whether to abort the operation, to replace the script (by issuing
the DELETESCRIPT <newname> after that) or to chose a different
name.
2. Download the old script with GETSCRIPT <oldname>.
3. Upload the old script with the new name: PUTSCRIPT <newname>.
4. If the old script was active (as reported by LISTSCRIPTS in step
1), then make the new script active: SETACTIVE <newname>
5. Delete the old script: DELETESCRIPT <oldname>
Note that these steps don't describe how to handle various other
error conditions (for example NO response containing QUOTA response
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code in step 3). Error handling is left as an excercise for the
reader.
2.11.2. NOOP Command
Arguments: String - tag to echo back (optional)
The NOOP command does nothing, beyond returning a response to the
client. It may be used by clients for protocol re-synchronisation or
to reset any inactivity auto-logout timer on the server.
The response to the NOOP command is always OK, followed by the TAG
response code together with the supplied string; if no string was
supplied in the NOOP command, the TAG response code MUST NOT be
included.
Older servers may not understand the NOOP client and robust clients
SHOULD be prepared to receive a NO response.
Examples:
C: NOOP
S: OK "NOOP completed"
C: NOOP "STARTTLS-SYNC-42"
S: OK (TAG {16}
S: STARTTLS-SYNC-42) "Done"
2.11.3. UNAUTHENTICATE Command
The UNAUTHENTICATE command returns the server to the non-
authenticated state. It doesn't affect any previously established
TLS [TLS] or SASL (Section 2.1) security layer.
The UNAUTHENTICATE command is only valid in authenticated state. If
issued in a wrong state, the server MUST reject it with a NO
response.
The UNAUTHENTICATE command has no parameters.
When issued in the authenticated state, the UNAUTHENTICATE command
MUST NOT fail (i.e. it must never return anything other than OK or
BYE)
3. Sieve URL Scheme
URI scheme name: sieve
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Status: permanent
URI scheme syntax:
Described using ABNF [ABNF] and ABNF entities from [URI-GEN].
sieveurl = sieveurl-server / sieveurl-list-scripts /
sieveurl-script
sieveurl-server = "sieve://" authority
sieveurl-list-scripts = "sieve://" [ authority ] ["/"]
sieveurl-script = "sieve://" [ authority ] "/" scriptname
scriptname = 1*pchar
URI scheme semantics:
A Sieve URL identifies a Sieve server or a Sieve script on a Sieve
server. The latter form is associated with the application/sieve
MIME type defined in [SIEVE]. There is no MIME type associated
with the former form of Sieve URI.
The server form is used in the REFERRAL response code in order to
designate another server where the client should perform its
operations.
The script form allows to retrieve (GETSCRIPT), update
(PUTSCRIPT), delete (DELETESCRIPT) or activate (SETACTIVE) the
named script, however the most typical action would be to retrieve
the script. If the script name is empty (omitted), the URI
requests that the client lists available scripts using the
LISTSCRIPTS command.
Encoding considerations: The script name, if present, is in UTF-8.
Non-US-ASCII UTF-8 octets MUST be percent-encoded as described in
[URI-GEN].
The user name (in the "authority" part), if present, is in UTF-8.
Non-US-ASCII UTF-8 octets MUST be percent-encoded as described in
[URI-GEN].
Applications/protocols that use this URI scheme name:
ManageSieve [RFC XXXX] clients and servers. Clients that can store
user preferences in protocols such as [LDAP] or [ACAP].
Interoperability considerations: None.
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Security considerations:
The <scriptname> part of a ManageSieve URL might potentially disclose
some confidential information about the author of the script or,
depending on a ManageSieve implementation, about configuration of the
mail server. The latter might be used to prepare for a more complex
attack on the mail system.
Clients resolving ManageSieve URLs that wish to achieve data
confidentiality and/or integrity SHOULD use the STARTTLS command (if
supported by the server) before starting authentication, or use a
SASL mechanism, such as GSSAPI, that provides a confidentiality
security layer.
Contact: Alexey Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
References: This document and RFC 5228 [SIEVE].
4. Formal Syntax
The following syntax specification uses the augmented Backus-Naur
Form (BNF) notation as specified in [ABNF]. This uses the ABNF core
rules as specified in Appendix A of the ABNF specification [ABNF].
"UTF8-2", "UTF8-3" and "UTF8-4" non-terminal are defined in [UTF-8].
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.
SAFE-CHAR = %x01-09 / %x0B-0C / %x0E-21 / %x23-5B /
%x5D-7F
;; any TEXT-CHAR except QUOTED-SPECIALS
QUOTED-CHAR = SAFE-UTF8-CHAR / DQUOTE QUOTED-SPECIALS
QUOTED-SPECIALS = DQUOTE / "\"
SAFE-UTF8-CHAR = SAFE-CHAR / UTF8-2 / UTF8-3 / UTF8-4
;; <UTF8-2>, <UTF8-3> and <UTF8-4>
;; are defined in [UTF-8]
ATOM-CHAR = "!" / %x23-27 / %x2A-5B / %x5D-7A / %x7C-7E
;; Any CHAR except ATOM-SPECIALS
ATOM-SPECIALS = "(" / ")" / "{" / SP / CTL /
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QUOTED-SPECIALS
QUOTED-SPECIALS = <"> / "\"
atom = 1*1024ATOM-CHAR
iana-token = atom
;; MUST be registered with IANA
auth-type = DQUOTE auth-type-name DQUOTE
auth-type-name = iana-token
;; as defined in SASL [SASL]
command = (command-any / command-auth /
command-nonauth) CRLF
;; Modal based on state
command-any = command-capability / command-logout /
command-noop
;; Valid in all states
command-auth = command-getscript / command-setactive /
command-listscripts / command-deletescript /
command-putscript /
command-havespace / /
command-renamescript /
command-unauthenticate
;; Valid only in Authenticated state
command-nonauth = command-authenticate / command-starttls
;; Valid only when in Non-Authenticated
;; state
command-authenticate = "AUTHENTICATE" SP auth-type [SP string]
*(CRLF string)
command-capability = "CAPABILITY"
command-deletescript = "DELETESCRIPT" SP sieve-name
command-getscript = "GETSCRIPT" SP sieve-name
command-havespace = "HAVESPACE" SP sieve-name SP number
command-listscripts = "LISTSCRIPTS"
command-noop = "NOOP" [SP string]
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command-logout = "LOGOUT"
command-putscript = "PUTSCRIPT" SP sieve-name SP sieve-script
sieve-script = string
command-renamescript = "RENAMESCRIPT" SP old-sieve-name SP
new-sieve-name
old-sieve-name = sieve-name
new-sieve-name = sieve-name
command-setactive = "SETACTIVE" SP sieve-name
command-starttls = "STARTTLS"
command-unauthenticate= "UNAUTHENTICATE"
extend-token = atom
;; MUST be defined by a standards track or
;; IESG approved experimental protocol
;; extension
extension-data = extension-item *(SP extension-item)
extension-item = extend-token / string / number /
"(" [extension-data] ")"
literal-c2s = "{" number "+}" CRLF *OCTET
;; The number represents the number of
;; octets.
;; This type of literal can only be sent
;; from the client to the server.
literal-s2c = "{" number "}" CRLF *OCTET
;; Almost identical to literal-c2s,
;; but with no '+' character.
;; The number represents the number of
;; octets.
;; This type of literal can only be sent
;; from the server to the client.
number = 1*DIGIT
;; A 32-bit unsigned number.
;; (0 <= n < 4,294,967,296)
quoted = DQUOTE *1024QUOTED-CHAR DQUOTE
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;; limited to 1024 octets between the <">s
resp-code = "AUTH-TOO-WEAK" / "ENCRYPT-NEEDED" /
"QUOTA" / resp-code-sasl /
resp-code-referral /
"TRANSITION-NEEDED" / "TRYLATER" /
"ACTIVE" / "NONEXISTENT" /
"ALREADYEXISTS" /
"TAG" SP string /
resp-code-ext
resp-code-referral = "REFERRAL" SP sieveurl
resp-code-sasl = "SASL" SP string
resp-code-name = iana-token
;; The response code name is hierarchical,
;; separated by '/'.
;; The response code name MUST NOT start
;; with '/'.
resp-code-ext = resp-code-name [SP extension-data]
;; unknown response codes MUST be tolerated
;; by the client.
response = response-authenticate /
response-logout /
response-getscript /
response-setactive /
response-listscripts /
response-deletescript /
response-putscript /
response-capability /
response-havespace /
response-starttls /
response-renamescript /
response-noop /
response-unauthenticate
response-authenticate = *(string CRLF)
((response-ok [response-capability]) /
response-nobye)
;; <response-capability> is REQUIRED if a
;; SASL security layer was negotiated and
;; MUST be omitted otherwise.
response-capability = *(single-capability) response-oknobye
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single-capability = capability-name [SP string] CRLF
capability-name = string
;; Note that literal-s2c is allowed.
initial-capabilities = DQUOTE "IMPLEMENTATION" DQUOTE SP string /
DQUOTE "SASL" DQUOTE SP sasl-mechs /
DQUOTE "SIEVE" DQUOTE SP sieve-extensions /
DQUOTE "NOTIFY" DQUOTE SP notify-mechs /
DQUOTE "STARTTLS" DQUOTE /
DQUOTE "LANGUAGE" DQUOTE SP language /
DQUOTE "RENAME" DQUOTE /
DQUOTE "NOOP" DQUOTE
;; Each capability conforms to
;; the syntax for single-capability.
;; Also note that the capability name
;; can be returned as either literal-s2c
;; or quoted, even though only "quoted"
;; string is shown above.
sasl-mechs = string
; space separated list of SASL mechanisms,
; each SASL mechanism name complies with rules
; specified in [SASL].
; Can be empty.
sieve-extensions = string
; space separated list of supported SIEVE extensions,
; can be empty.
language = string
; Contains <Language-Tag> from [RFC4646].
notify-mechs = string
; space separated list of URI schema parts
; for supported notification [NOTIFY] methods.
; MUST NOT be empty.
response-deletescript = response-oknobye
response-getscript = (sieve-script CRLF response-ok) /
response-nobye
response-havespace = response-oknobye
response-listscripts = *(sieve-name [SP "ACTIVE"] CRLF)
response-oknobye
;; ACTIVE may only occur with one sieve-name
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response-logout = response-oknobye
response-unauthenticate= response-oknobye
;; "NO" response can only be returned when
;; the command is issued in a wrong state
;; or has a wrong number of parameters
response-ok = "OK" [SP "(" resp-code ")"]
[SP string] CRLF
;; The string contains human readable text
;; encoded as UTF-8.
response-nobye = ("NO" / "BYE") [SP "(" resp-code ")"]
[SP string] CRLF
;; The string contains human readable text
;; encoded as UTF-8.
response-oknobye = response-ok / response-nobye
response-noop = response-ok
response-putscript = response-oknobye
response-renamescript = response-oknobye
response-setactive = response-oknobye
response-starttls = (response-ok response-capability) /
response-nobye
sieve-name = string
;; See Section 1.6 for the full list of
;; prohibited characters.
string = quoted / literal-c2s / literal-s2c
;; literal-c2s is only allowed when sent
;; from the client to the server.
;; literal-s2c is only allowed when sent
;; from the server to the client.
;; quoted is allowed in either direction.
5. Security Considerations
The AUTHENTICATE command uses SASL [SASL] to provide authentication
and authorization services. Integrity and privacy services can be
provided by [SASL] and/or [TLS]. When a SASL mechanism is used the
security considerations for that mechanism apply.
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This protocol's transactions are susceptible to passive observers or
man in the middle attacks which alter the data, unless the optional
encryption and integrity services of the SASL (via the AUTHENTICATE
command) and/or [TLS] (via the STARTTLS command) are enabled, or an
external security mechanism is used for protection. It may be useful
to allow configuration of both clients and servers to refuse to
transfer sensitive information in the absence of strong encryption.
If an implementation supports SASL mechanisms that are vulnerable to
passive eavesdropping attacks (such as [PLAIN]), then the
implementation MUST support at least one configuration where these
SASL mechanisms are not advertised or used without the presence of an
external security layer such as [TLS].
Some response codes returned on failed AUTHENTICATE command may
disclose whether or not the username is valid, so server
implementations SHOULD provide the ability to disable these features
(or make them not conditional on a per-user basis) for sites
concerned about such disclosure. In the case of ENCRYPT-NEEDED, if
it is applied to all identities then no extra information is
disclosed, but if it is applied on a per-user basis it can disclose
information.
6. IANA Considerations
IANA is requested to reserve TCP port number 2000 for use with the
Manage Sieve protocol described in this document.
IANA is requested to register the "sieve" URI scheme defined in
Section 3 of this document.
IANA is requested to create a new registry for Manage Sieve
capabilities. The registration template for Manage Sieve
capabilities is specified in Section 6.1. Manage Sieve protocol
capabilities MUST be specified in a standards track or IESG approved
experimental RFC.
IANA is requested to create a new registry for Manage Sieve response
codes. The registration template for Manage Sieve response codes is
specified in Section 6.3. Manage Sieve protocol response codes MUST
be specified in a standards track or IESG approved experimental RFC.
6.1. Manage Sieve Capability Registration Template
To: iana@iana.org
Subject: Manage Sieve Capability Registration
Please register the following Manage Sieve Capability:
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Capability name:
Description:
Relevant publications:
Person & email address to contact for further information:
Author/Change controller:
6.2. Registration of Initial Manage Sieve capabilities
To: iana@iana.org
Subject: Manage Sieve Capability Registration
Please register the following Manage Sieve Capabilities:
Capability name: IMPLEMENTATION
Description: Its value contains name of server implementation and
its version.
Relevant publications: this RFC, Section 1.7.
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
Capability name: SASL
Description: Its value contains a space separated list of SASL
mechanisms supported by server.
Relevant publications: this RFC, Section 1.7 and Section 2.1.
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
Capability name: SIEVE
Description: Its value contains a space separated list of
supported SIEVE extensions
Relevant publications: this RFC, Section 1.7. Also [SIEVE].
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
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Capability name: STARTTLS
Description: This capability is returned if server supports TLS
(STARTTLS command).
Relevant publications: this RFC, Section 1.7 and Section 2.2.
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
Capability name: NOTIFY
Description: This capability is returned if server supports
'enotify' [NOTIFY] Sieve extension.
Relevant publications: this RFC, Section 1.7.
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
Capability name: RENAME
Description: This capability is returned if the server supports
the RENAMESCRIPT command.
Relevant publications: this RFC, Section 2.11.1.
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
Capability name: NOOP
Description: This capability is returned if the server supports
the NOOP command.
Relevant publications: this RFC, Section 2.11.2.
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
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6.3. Manage Sieve Response Code Registration Template
To: iana@iana.org
Subject: Manage Sieve Response Code Registration
Please register the following Manage Sieve Response Code:
Response Code:
Arguments (use ABNF to specify syntax, or the word NONE if none
can be specified):
Purpose:
Published Specification(s):
Person & email address to contact for further information:
Author/Change controller:
6.4. Registration of Initial Manage Sieve Response Codes
To: iana@iana.org
Subject: Manage Sieve Response Code Registration
Please register the following Manage Sieve Response Codes:
Response Code: AUTH-TOO-WEAK
Arguments (use ABNF to specify syntax, or the word NONE if none
can be specified): NONE
Purpose: This response code is returned in the NO response from an
AUTHENTICATE command. It indicates that site security policy
forbids the use of the requested mechanism for the specified
authentication identity.
Published Specification(s): [RFCXXXX]
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
Response Code: ENCRYPT-NEEDED
Arguments (use ABNF to specify syntax, or the word NONE if none
can be specified): NONE
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Purpose: This response code is returned in the NO response from an
AUTHENTICATE command. It indicates that site security policy
requires the use of a strong encryption mechanism for the
specified authentication identity and mechanism.
Published Specification(s): [RFCXXXX]
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
Response Code: QUOTA
Arguments (use ABNF to specify syntax, or the word NONE if none
can be specified): NONE
Purpose: If this response code is returned in the NO/BYE response,
it means that the command would have placed the user above the
site-defined quota constraints. If this response code is returned
in the OK response, it can mean that the user is near its quota or
that the user exceeded its quota, but the server supports soft
quotas.
Published Specification(s): [RFCXXXX]
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
Response Code: REFERRAL
Arguments (use ABNF to specify syntax, or the word NONE if none
can be specified): <sieveurl>
Purpose: This response code may be returned with a BYE result from
any command, and includes a mandatory parameter that indicates
what server to access to manage this user's sieve scripts. The
server will be specified by a Sieve URL (see Section 3). The
scriptname portion of the URL MUST NOT be specified. The client
should authenticate to the specified server and use it for all
further commands in the current session.
Published Specification(s): [RFCXXXX]
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
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Author/Change controller: IESG.
Response Code: SASL
Arguments (use ABNF to specify syntax, or the word NONE if none
can be specified): <string>
Purpose: This response code can occur in the OK response to a
successful AUTHENTICATE command and includes the optional final
server response data from the server as specified by [SASL].
Published Specification(s): [RFCXXXX]
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
Response Code: TRANSITION-NEEDED
Arguments (use ABNF to specify syntax, or the word NONE if none
can be specified): NONE
Purpose: This response code occurs in a NO response of an
AUTHENTICATE command. It indicates that the user name is valid,
but the entry in the authentication database needs to be updated
in order to permit authentication with the specified mechanism.
This is typically done by establishing a secure channel using TLS,
followed by authenticating once using the [PLAIN] authentication
mechanism. The selected mechanism SHOULD then work for
authentications in subsequent sessions.
Published Specification(s): [RFCXXXX]
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
Response Code: TRYLATER
Arguments (use ABNF to specify syntax, or the word NONE if none
can be specified): NONE
Purpose: A command failed due to a temporary server failure. The
client MAY continue using local information and try the command
later. This response code only make sense when returned in a NO/
BYE response.
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Published Specification(s): [RFCXXXX]
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Author/Change controller: IESG.
7. Acknowledgements
Thanks to Simon Josefsson, Larry Greenfield, Allen Johnson, Chris
Newman, Lyndon Nerenberg, Tim Showalter, Sarah Robeson, Walter Wong,
Barry Leiba, Arnt Gulbrandsen, Stephan Bosch, Ken Murchison, Phil
Pennock, Jeffrey Hutzelman, Mark E. Mallett, Dave Cridland and Robert
Burrell Donkin for help with this document. Special thank you to
Phil Pennock for providing text for the NOOP command, as well as
finding various bugs in the document.
8. References
8.1. Normative References
[ABNF] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 5234, January 2008.
[ACAP] Newman, C. and J. Myers, "ACAP -- Application
Configuration Access Protocol", RFC 2244, November 1997.
[BASE64] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, October 2006.
[DNS-SRV] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782,
February 2000.
[KEYWORDS]
Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[NET-UNICODE]
Klensin, J. and M. Padlipsky, "Unicode Format for Network
Interchange", RFC 5198, March 2008.
[NOTIFY] Melnikov, A., Ed., Leiba, B., Ed., Segmuller, W., and T.
Martin, "Sieve Extension: Notifications",
draft-ietf-sieve-notify-12 (work in progress),
December 2007.
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[RFC2277] Alvestrand, H., "IETF Policy on Character Sets and
Languages", RFC 2277, January 1998.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[RFC3490] Faltstrom, P., Hoffman, P., and A. Costello,
"Internationalizing Domain Names in Applications (IDNA)",
RFC 3490, March 2003.
[RFC4519] Sciberras, A., "Lightweight Directory Access Protocol
(LDAP): Schema for User Applications", RFC 4519,
June 2006.
[RFC4646] Phillips, A. and M. Davis, "Tags for Identifying
Languages", RFC 4646, September 2006.
[RFC791] Postel, J., "Internet Protocol", RFC 791, September 1981.
[SASL] Melnikov, A. and K. Zeilenga, "Simple Authentication and
Security Layer (SASL)", RFC 4422, June 2006.
[SASL-ANON]
Zeilenga, K., "Anonymous Simple Authentication and
Security Layer (SASL) Mechanism", RFC 4505, June 2006.
[SASLprep]
Zeilenga, K., "SASLprep: Stringprep Profile for User Names
and Passwords", RFC 4013, February 2005.
[SCRAM] Menon-Sen, A., Ed. and C. Newman, "Salted Challenge
Response Authentication Mechanism (SCRAM)",
draft-newman-auth-scram-05.txt (work in progress),
December 2007.
[SIEVE] Guenther, P., Ed. and T. Showalter, Ed., "Sieve: An Email
Filtering Language", RFC 5228, January 2008.
[StringPrep]
Hoffman, P. and M. Blanchet, "Preparation of
Internationalized Strings ("stringprep")", RFC 3454,
December 2002.
[TLS] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.1", RFC 4346, April 2006.
[URI-GEN] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
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RFC 3986, January 2005.
[UTF-8] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003.
[X509] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet
X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile", RFC 3280,
April 2002.
[X509-SRV]
Santesson, S., "Internet X.509 Public Key Infrastructure
Subject Alternative Name for Expression of Service Name",
RFC 4985, August 2007.
8.2. Informative References
[DIGEST-MD5]
Leach, P. and C. Newman, "Using Digest Authentication as a
SASL Mechanism", RFC 2831, May 2000.
[IANA-GUIDELINES]
Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[IMAP4rev1]
Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
4rev1", RFC 3501, March 2003.
[LDAP] Zeilenga, K., "Lightweight Directory Access Protocol
(LDAP): Technical Specification Road Map", RFC 4510,
June 2006.
[PLAIN] Zeilenga, K., "The PLAIN Simple Authentication and
Security Layer (SASL) Mechanism", RFC 4616, August 2006.
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Authors' Addresses
Alexey Melnikov (editor)
Isode Limited
5 Castle Business Village
36 Station Road
Hampton, Middlesex TW12 2BX
UK
Email: Alexey.Melnikov@isode.com
Tim Martin
BeThereBeSquare Inc.
672 Haight st.
San Francisco, CA 94117
US
Phone: +1 510 260-4175
Email: timmartin@alumni.cmu.edu
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Full Copyright Statement
Copyright (C) The IETF Trust (2008).
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contained in BCP 78, and except as set forth therein, the authors
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Melnikov & Martin Expires March 17, 2009 [Page 42]
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