Dovecot v2.3.15 released

Hi,

Here's a new release with some security fixes and quite a lot of other changes as well.

https://dovecot.org/releases/2.3/dovecot-2.3.15.tar.gz <https://dovecot.org/releases/2.3/dovecot-2.3.15.tar.gz> https://dovecot.org/releases/2.3/dovecot-2.3.15.tar.gz.sig <https://dovecot.org/releases/2.3/dovecot-2.3.15.tar.gz.sig>

Binary packages in https://repo.dovecot.org/ <https://repo.dovecot.org/> Docker images in https://hub.docker.com/r/dovecot/dovecot <https://hub.docker.com/r/dovecot/dovecot>

• 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...

• 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.