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A dovecot security update has been released for Fedora 33.



SECURITY: Fedora 33 Update: dovecot-2.3.15-1.fc33


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Fedora Update Notification
FEDORA-2021-891c1ab1ac
2021-07-05 01:35:53.935167
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Name : dovecot
Product : Fedora 33
Version : 2.3.15
Release : 1.fc33
URL :   http://www.dovecot.org/
Summary : Secure imap and pop3 server
Description :
Dovecot is an IMAP server for Linux/UNIX-like systems, written with security
primarily in mind. It also contains a small POP3 server. It supports mail
in either of maildir or mbox formats.

The SQL drivers and authentication plug-ins are in their subpackages.

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Update Information:

* CVE-2021-29157: Dovecot does not correctly escape kid and azp fields in
JWT tokens. This may be used to supply attacker controlled keys to
validate tokens, if attacker has local access. * CVE-2021-33515: On-path
attacker could have injected plaintext commands before STARTTLS
negotiation that would be executed after STARTTLS finished with the
client. * Disconnection log messages are now more standardized across services.
They also always now start with "Disconnected" prefix. * Dovecot now depends on
libsystemd for systemd integration. * Removed support for Lua 5.2. Use version
5.1 or 5.3 instead. * config: Some settings are now marked as "hidden". It's
discouraged to change these settings. They will no longer be visible in
doveconf output, except if they have been changed or if doveconf -s
parameter is used. See   https://doc.dovecot.org/settings/advanced/ for
details. * imap-compress: Compression level is now algorithm specific.
See   https://doc.dovecot.org/settings/plugin/compress-plugin/ * indexer-worker:
Convert "Indexed" info logs to an event named
"indexer_worker_indexing_finished". See
  https://doc.dovecot.org/admin_manual/list_of_events/#indexer-worker-indexing-
finished + Add TSLv1.3 support to min_protocols. + Allow configuring
ssl_cipher_suites. (for TLSv1.3+) + acl: Add acl_ignore_namespace setting which
allows to entirely ignore ACLs for the listed namespaces. + imap:
Support official RFC8970 preview/snippet syntax. Old methods of
retrieving preview information via IMAP commands ("SNIPPET and PREVIEW
with explicit algorithm selection") have been deprecated. + imapc: Support
INDEXPVT for imapc storage to enable private message flags for cluster
wide shared mailboxes. + lib-storage: Add new events: mail_opened,
mail_expunge_requested, mail_expunged, mail_cache_lookup_finished. See
  https://doc.dovecot.org/admin_manual/list_of_events/#mail + zlib, imap-
compression, fs-compress: Support compression levels that the
algorithm supports. Before, we would allow hardcoded value between 1
to 9 and would default to 6. Now we allow using per-algorithm value
range and default to whatever default the algorithm specifies. - *-login:
Commands pipelined together with and just after the authenticate
command cause these commands to be executed twice. This applies to all
protocols that involve user login, which currently comprises of imap,
pop3, submisision and managesieve. - *-login: Processes are supposed to
disconnect the oldest non-logged in connection when process_limit was
reached. This didn't actually happen with the default "high-security
mode" (with service_count=1) where each connection is handled by a
separate process. - *-login: When login process reaches client/process limits,
oldest client connections are disconnected. If one of these was still
doing anvil lookup, this caused a crash. This could happen only if the
login process limits were very low or if the server was overloaded. -
Fixed building with link time optimizations (-flto). - auth: Userdb iteration
with passwd driver does not always return all users with some nss
drivers. - dsync: Shared INBOX not synced when "mail_shared_explicit_inbox" was
disabled. If a user has a shared mailbox which is another user's INBOX,
dsync didn't include the mailbox in syncing unless explicit naming is
enabled with "mail_shared_explicit_inbox" set to "yes". - dsync: Shared
namespaces were not synced with "-n" flag. - dsync: Syncing shared INBOX failed
if mail_attribute_dict was not set. If a user has a shared mailbox
that is another user's INBOX, dsync failed to export the mailbox if
mail attributes are disabled. - fts-solr, fts-tika: Using both Solr FTS and Tika
may have caused HTTP requests to assert-crash: Panic: file http-
client-request.c: line 1232 (http_client_request_send_more): assertion
failed: (req->payload_input != NULL) - fts-tika: 5xx errors returned by Tika
server as indexing failures. However, Tika can return 5xx for some
attachments every time. So the 5xx error should be retried once, but
treated as success if it happens on the retry as well. v2.3
regression. - fts-tika: v2.3.11 regression: Indexing messages with fts-tika may
have resulted in Panic: file message-parser.c: line 802
(message_parser_deinit_from_parts): assertion failed:
(ctx->nested_parts_count == 0 || i_stream_have_bytes_left(ctx->input)) - imap:
SETMETADATA could not be used to unset metadata values. Instead NIL
was handled as a "NIL" string. v2.3.14 regression. - imap: IMAP BINARY FETCH
crashes at least on empty base64 body: Panic: file index-mail-
binary.c: line 358 (blocks_count_lines): assertion failed:
(block_count == 0 || block_idx+1 == block_count) - imap: If IMAP client using
the NOTIFY command was disconnected while sending FETCH notifications
to the client, imap could crash with Panic: Trying to close mailbox
INBOX with open transactions. - imap: Using IMAP COMPRESS extension can cause
IMAP connection to hang when IMAP commands are >8 kB long. - imapc: If
remote server sent BYE but didn't immediately disconnect, it could
cause infinite busy-loop. - lib-index: Corrupted cache record size in
dovecot.index.cache file could have caused a crash (segfault) when
accessing it. - lib-oauth2: JWT token time validation now works correctly with
32-bit systems. - lib-ssl-iostream: Checking hostnames against an SSL
certificate was case-sensitive. - lib-storage: Corrupted mime.parts in
dovecot.index.cache may have resulted in Panic: file imap-
bodystructure.c: line 206 (part_write_body): assertion failed: (text
== ((part->flags & MESSAGE_PART_FLAG_TEXT) != 0)) - lib-storage: Index
rebuilding (e.g. via doveadm force-resync) didn't preserve the "hdr-
pop3-uidl" header. Because of this, the next pop3 session could have
accessed all of the emails' metadata to read their POP3 UIDL (opening
dbox files). - listescape: When using the listescape plugin and a shared
namespace the plugin didn't work properly anymore resulting in errors
like: "Invalid mailbox name: Name must not have '/' character." -
lmtp: Connection crashes if connection gets disconnected due to
multiple bad commands and the last bad command is BDAT. - lmtp: The Dovecot-
specific LMTP parameter XRCPTFORWARD was blindly forwarded by LMTP
proxy without checking that the backend has support. This caused a
command parameter error from the backend if it was running an older
Dovecot release. This could only occur in more complex setups where
the message was proxied twice; when the proxy generated the
XRCPTFORWARD parameter itself the problem did not occur, so this only
happened when it was forwarded. - lmtp: The LMTP proxy crashes with a panic when
the remote server replies with an error while the mail is still being
forwarded through a DATA/BDAT command. - lmtp: Username may have been
missing from lmtp log line prefixes when it was performing
autoexpunging. - master: Dovecot would incorrectly fail with haproxy 2.0.14
service checks. - master: Systemd service: Dovecot announces readiness
for accepting connections earlier than it should. The following
environment variables are now imported automatically and can be
omitted from import_environment setting: NOTIFY_SOCKET LISTEN_FDS
LISTEN_PID. - master: service { process_min_avail } was launching processes too
slowly when master was forking a lot of processes. - util: Make the health-
check.sh example script POSIX shell compatible.
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ChangeLog:

* Mon Jun 21 2021 Michal Hlavinka - 1:2.3.15-1
- dovecot updated to 2.3.15, pigeonhole updated to 0.5.15
- CVE-2021-29157: Dovecot does not correctly escape kid and azp fields in
JWT tokens. This may be used to supply attacker controlled keys to
validate tokens, if attacker has local access.
- CVE-2021-33515: On-path attacker could have injected plaintext commands
before STARTTLS negotiation that would be executed after STARTTLS
finished with the client.
- Add TSLv1.3 support to min_protocols.
- Allow configuring ssl_cipher_suites. (for TLSv1.3+)
* Wed May 19 2021 Pete Walter - 1:2.3.14-4
- Rebuild for ICU 69
* Wed May 19 2021 Pete Walter - 1:2.3.14-3
- Rebuild for ICU 69
* Mon May 10 2021 Jeff Law - 1:2.3.14-2
- Re-enable LTO
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References:

[ 1 ] Bug #1974392 - CVE-2021-29157 dovecot: local attacker can login as any user and access their emails [fedora-all]
  https://bugzilla.redhat.com/show_bug.cgi?id=1974392
[ 2 ] Bug #1974393 - CVE-2021-33515 dovecot: plaintext commands injection [fedora-all]
  https://bugzilla.redhat.com/show_bug.cgi?id=1974393
[ 3 ] Bug #1974394 - CVE-2020-28200 dovecot: insufficient protection against excessive resource usage allows for a DoS [fedora-all]
  https://bugzilla.redhat.com/show_bug.cgi?id=1974394
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This update can be installed with the "dnf" update program. Use
su -c 'dnf upgrade --advisory FEDORA-2021-891c1ab1ac' at the command
line. For more information, refer to the dnf documentation available at
  http://dnf.readthedocs.io/en/latest/command_ref.html#upgrade-command-label

All packages are signed with the Fedora Project GPG key. More details on the
GPG keys used by the Fedora Project can be found at
  https://fedoraproject.org/keys