-Change log file for Exim from version 4.21
-------------------------------------------
This document describes *changes* to previous versions, that might
affect Exim's operation, with an unchanged configuration file. For new
options, and new features, see the NewStuff file next to this ChangeLog.
+Exim version 4.94
+-----------------
+
+JH/01 Avoid costly startup code when not strictly needed. This reduces time
+ for some exim process initialisations. It does mean that the logging
+ of TLS configuration problems is only done for the daemon startup.
+
+JH/02 Early-pipelining support code is now included unless disabled in Makefile.
+
+JH/03 DKIM verification defaults no long accept sha1 hashes, to conform to
+ RFC 8301. They can still be enabled, using the dkim_verify_hashes main
+ option.
+
+JH/04 Support CHUNKING from an smtp transport using a transport_filter, when
+ DKIM signing is being done. Previously a transport_filter would always
+ disable CHUNKING, falling back to traditional DATA.
+
+JH/05 Regard command-line receipients as tainted.
+
+JH/06 Bug 340: Remove the daemon pid file on exit, whe due to SIGTERM.
+
+JH/07 Bug 2489: Fix crash in the "pam" expansion condition. It seems that the
+ PAM library frees one of the arguments given to it, despite the
+ documentation. Therefore a plain malloc must be used.
+
+JH/08 Bug 2491: Use tainted buffers for the transport smtp context. Previously
+ on-stack buffers were used, resulting in a taint trap when DSN information
+ copied from a received message was written into the buffer.
+
+JH/09 Bug 2493: Harden ARC verify against Outlook, whick has been seen to mix
+ the ordering of its ARC headers. This caused a crash.
+
+JH/10 Bug 2492: Use tainted memory for retry record when needed. Previously when
+ a new record was being constructed with information from the peer, a trap
+ was taken.
+
+JH/11 Bug 2494: Unset the default for dmarc_tld_file. Previously a naiive
+ installation would get error messages from DMARC verify, when it hit the
+ nonexistent file indicated by the default. Distros wanting DMARC enabled
+ should both provide the file and set the option.
+ Also enforce no DMARC verification for command-line sourced messages.
+
+JH/12 Fix an uninitialised flag in early-pipelining. Previously connections
+ could, depending on the platform, hang at the STARTTLS response.
+
+JH/13 Bug 2498: Reset a counter used for ARC verify before handling another
+ message on a connection. Previously if one message had ARC headers and
+ the following one did not, a crash could result when adding an
+ Authentication-Results: header.
+
+JH/14 Bug 2500: Rewind some of the common-coding in string handling between the
+ Exim main code and Exim-related utities. The introduction of taint
+ tracking also did many adjustments to string handling. Since then, eximon
+ frequently terminated with an assert failure.
+
+JH/15 When PIPELINING, synch after every hundred or so RCPT commands sent and
+ check for 452 responses. This slightly helps the inefficieny of doing
+ a large alias-expansion into a recipient-limited target. The max_rcpt
+ transport option still applies (and at the current default, will override
+ the new feature). The check is done for either cause of synch, and forces
+ a fast-retry of all 452'd recipients using a new MAIL FROM on the same
+ connection. The new facility is not tunable at this time.
+
+JH/16 Fix the variables set by the gsasl authenticator. Previously a pointer to
+ library live data was being used, so the results became garbage. Make
+ copies while it is still usable.
+
+JH/17 Logging: when the deliver_time selector ise set, include the DT= field
+ on delivery deferred (==) and failed (**) lines (if a delivery was
+ attemtped). Previously it was only on completion (=>) lines.
+
+
+Exim version 4.93
+-----------------
+
+JH/01 OpenSSL: With debug enabled output keying information sufficient, server
+ side, to decode a TLS 1.3 packet capture.
+
+JH/02 OpenSSL: Suppress the sending of (stateful) TLS1.3 session tickets.
+ Previously the default library behaviour applied, sending two, each in
+ its own TCP segment.
+
+JH/03 Debug output for ACL now gives the config file name and line number for
+ each verb.
+
+JH/04 The default received_header_text now uses the RFC 8314 tls cipher clause.
+
+JH/05 DKIM: ensure that dkim_domain elements are lowercased before use.
+
+JH/06 Fix buggy handling of autoreply bounce_return_size_limit, and a possible
+ buffer overrun for (non-chunking) other transports.
+
+JH/07 GnuTLS: Our use of late (post-handshake) certificate verification, under
+ TLS1.3, means that a server rejecting a client certificate is not visible
+ to the client until the first read of encrypted data (typically the
+ response to EHLO). Add detection for that case and treat it as a failed
+ TLS connection attempt, so that the normal retry-in-clear can work (if
+ suitably configured).
+
+JB/01 Bug 2375: fix expansions of 822 addresses having comments in local-part
+ and/or domain. Found and fixed by Jason Betts.
+
+JH/08 Add hardening against SRV & TLSA lookups the hit CNAMEs (a nonvalid
+ configuration). If a CNAME target was not a wellformed name pattern, a
+ crash could result.
+
+JH/09 Logging: Fix initial listening-on line for multiple ports for an IP when
+ the OS reports them interleaved with other addresses.
+
+JH/10 OpenSSL: Fix aggregation of messages. Previously, when PIPELINING was
+ used both for input and for a verify callout, both encrypted, SMTP
+ responses being sent by the server could be lost. This resulted in
+ dropped connections and sometimes bounces generated by a peer sending
+ to this system.
+
+JH/11 Harden plaintext authenticator against a badly misconfigured client-send
+ string. Previously it was possible to cause undefined behaviour in a
+ library routine (usually a crash). Found by "zerons".
+
+JH/12 Bug 2384: fix "-bP smtp_receive_timeout". Previously it returned no
+ output.
+
+JH/13 Bug 2386: Fix builds with Dane under LibreSSL 2.9.0 onward. Some old
+ API was removed, so update to use the newer ones.
+
+JH/14 Bug 1891: Close the log file if receiving a non-smtp message, without
+ any timeout set, is taking a long time. Previously we would hang on to a
+ rotated logfile "forever" if the input was arriving with long gaps
+ (a previous attempt to fix addressed lack, for a long time, of initial
+ input).
+
+HS/01 Bug 2390: Use message_id for tempfile creation to avoid races in a
+ shared (NFS) environment. The length of the tempfile name is now
+ 4 + 16 ("hdr.$message_exim_id") which might break on file
+ systems which restrict the file name length to lower values.
+ (It was "hdr.$pid".)
+
+HS/02 Bug 2390: Use message_id for tempfile creation to avoid races in a
+ shared (NFS) environment.
+
+HS/03 Bug 2392: exigrep does case sensitive *option* processing (as it
+ did for all versions <4.90). Notably -M, -m, --invert, -I may be
+ affected.
+
+JH/15 Use unsigned when creating bitmasks in macros, to avoid build errors
+ on some platforms for bit 31.
+
+JH/16 GnuTLS: rework ciphersuite strings under recent library versions. Thanks
+ to changes apparently associated with TLS1.3 handling some of the APIs
+ previously used were either nonfunctional or inappropriate. Strings
+ like TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM__AEAD:256
+ and TLS1.2:ECDHE_SECP256R1__RSA_SHA256__AES_128_CBC__SHA256:128 replace
+ the previous TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256 .
+ This affects log line X= elements, the $tls_{in,out}_cipher variables,
+ and the use of specific cipher names in the encrypted= ACL condition.
+
+JH/17 OpenSSL: the default openssl_options now disables ssl_v3.
+
+JH/18 GnuTLS: fix $tls_out_ocsp under hosts_request_ocsp. Previously the
+ verification result was not updated unless hosts_require_ocsp applied.
+
+JH/19 Bug 2398: fix listing of a named-queue. Previously, even with the option
+ queue_list_requires_admin set to false, non-admin users were denied the
+ facility.
+
+JH/20 Bug 2389: fix server advertising of usable certificates, under GnuTLS in
+ directory-of-certs mode. Previously they were advertised despite the
+ documentation.
+
+JH/21 The smtp transport option "hosts_noproxy_tls" is now unset by default.
+ A single TCP connection by a client will now hold a TLS connection open
+ for multiple message deliveries, by default. Previoud the default was to
+ not do so.
+
+JH/22 The smtp transport option "hosts_try_dane" now enables all hosts by
+ default. If built with the facility, DANE will be used. The facility
+ SUPPORT_DANE is now enabled in the prototype build Makefile "EDITME".
+
+JH/23 The build default is now for TLS to be included; the SUPPORT_TLS define
+ is replaced with DISABLE_TLS. Either USE_GNUTLS or (the new) USE_OPENSSL
+ must be defined and you must still, unless you define DISABLE_TLS, manage
+ the the include-dir and library-file requirements that go with that
+ choice. Non-TLS builds are still supported.
+
+JH/24 Fix duplicated logging of peer name/address, on a transport connection-
+ reject under TFO.
+
+JH/25 The smtp transport option "hosts_try_fastopen" now enables all hosts by
+ default. If the platform supports and has the facility enabled, it will
+ be requested on all coneections.
+
+JH/26 The PIPE_CONNECT facility is promoted from experimental status and is now
+ controlled by the build-time option SUPPORT_PIPE_CONNECT.
+
+PP/01 Unbreak heimdal_gssapi, broken in 4.92.
+
+JH/27 Bug 2404: Use the main-section configuration option "dsn_from" for
+ success-DSN messages. Previously the From: header was always the default
+ one for these; the option was ignored.
+
+JH/28 Fix the timeout on smtp response to apply to the whole response.
+ Previously it was reset for every read, so a teergrubing peer sending
+ single bytes within the time limit could extend the connection for a
+ long time. Credit to Qualsys Security Advisory Team for the discovery.
+
+JH/29 Fix DSN Final-Recipient: field. Previously it was the post-routing
+ delivery address, which leaked information of the results of local
+ forwarding. Change to the original envelope recipient address, per
+ standards.
+
+JH/30 Bug 2411: Fix DSN generation when RFC 3461 failure notification is
+ requested. Previously not bounce was generated and a log entry of
+ error ignored was made.
+
+JH/31 Avoid re-expansion in ${sort } expansion. (CVE-2019-13917)
+
+JH/32 Introduce a general tainting mechanism for values read from the input
+ channel, and values derived from them. Refuse to expand any tainted
+ values, to catch one form of exploit.
+
+JH/33 Bug 2413: Fix dkim_strict option. Previously the expansion result
+ was unused and the unexpanded text used for the test. Found and
+ fixed by Ruben Jenster.
+
+JH/34 Fix crash after TLS shutdown. When the TCP/SMTP channel was left open,
+ an attempt to use a TLS library read routine dereffed a nul pointer,
+ causing a segfault.
+
+JH/35 Bug 2409: filter out-of-spec chars from callout response before using
+ them in our smtp response.
+
+JH/36 Have the general router option retry_use_local_part default to true when
+ any of the restrictive preconditions are set (to anything). Previously it
+ was only for check_local user. The change removes one item of manual
+ configuration which is required for proper retries when a remote router
+ handles a subset of addresses for a domain.
+
+JH/37 Appendfile: when evaluating quota use (non-quota_size_regex) take the file
+ link count into consideration.
+
+HS/04 Fix handling of very log lines in -H files. If a -<key> <value> line
+ caused the extension of big_buffer, the following lines were ignored.
+
+JH/38 Bug 1395: Teach the DNS negative-cache about TTL value from the SOA in
+ accordance with RFC 2308. Previously there was no expiry, so a longlived
+ receive process (eg. due to ACL delays) versus a short SOA value could
+ surprise.
+
+HS/05 Handle trailing backslash gracefully. (CVE-2019-15846)
+
+JH/39 Promote DMARC support to mainline.
+
+JH/40 Bug 2452: Add a References: header to DSNs.
+
+JH/41 With GnuTLS 3.6.0 (and later) do not attempt to manage Diffie-Hellman
+ parameters. The relevant library call is documented as "Deprecated: This
+ function is unnecessary and discouraged on GnuTLS 3.6.0 or later. Since
+ 3.6.0, DH parameters are negotiated following RFC7919."
+
+HS/06 Change the default of dnssec_request_domains to "*"
+
+JH/42 Bug 2545: Fix CHUNKING for all RCPT commands rejected. Previously we
+ carried on and emitted a BDAT command, even when PIPELINING was not
+ active.
+
+JH/43 Bug 2465: Fix taint-handling in dsearch lookup. Previously a nontainted
+ buffer was used for the filename, resulting in a trap when tainted
+ arguments (eg. $domain) were used.
+
+JH/44 With OpenSSL 1.1.1 (onwards) disable renegotiation for TLS1.2 and below;
+ recommended to avoid a possible server-load attack. The feature can be
+ re-enabled via the openssl_options main cofiguration option.
+
+JH/45 local_scan API: documented the current smtp_printf() call. This changed
+ for version 4.90 - adding a "more data" boolean to the arguments.
+ Bumped the ABI version number also, this having been missed previously;
+ release versions 4.90 to 4.92.3 inclusive were effectively broken in
+ respect of usage of smtp_printf() by either local_scan code or libraries
+ accessed via the ${dlfunc } expansion item. Both will need coding
+ adjustment for any calls to smtp_printf() to match the new function
+ signature; a FALSE value for the new argument is always safe.
+
+JH/46 FreeBSD: fix use of the sendfile() syscall. The shim was not updating
+ the file-offset (which the Linux syscall does, and exim expects); this
+ resulted in an indefinite loop.
+
+JH/47 ARC: fix crash in signing, triggered when a configuration error failed
+ to do ARC verification. The Authentication-Results: header line added
+ by the configuration then had no ARC item.
+
+
+Exim version 4.92
+-----------------
+
+JH/01 Remove code calling the customisable local_scan function, unless a new
+ definition "HAVE_LOCAL_SCAN=yes" is present in the Local/Makefile.
+
+JH/02 Bug 1007: Avoid doing logging from signal-handlers, as that can result in
+ non-signal-safe functions being used.
+
+JH/03 Bug 2269: When presented with a received message having a stupidly large
+ number of DKIM-Signature headers, disable DKIM verification to avoid
+ a resource-consumption attack. The limit is set at twenty.
+
+JH/04 Add variables $arc_domains, $arc_oldest_pass for ARC verify. Fix the
+ report of oldest_pass in ${authres } in consequence, and separate out
+ some descriptions of reasons for verification fail.
+
+JH/05 Bug 2273: Cutthrough delivery left a window where the received messsage
+ files in the spool were present and unlocked. A queue-runner could spot
+ them, resulting in a duplicate delivery. Fix that by doing the unlock
+ after the unlink. Investigation by Tim Stewart. Take the opportunity to
+ add more error-checking on spoolfile handling while that code is being
+ messed with.
+
+PP/01 Refuse to open a spool data file (*-D) if it's a symlink.
+ No known attacks, no CVE, this is defensive hardening.
+
+JH/06 Bug 2275: The MIME ACL unlocked the received message files early, and
+ a queue-runner could start a delivery while other operations were ongoing.
+ Cutthrough delivery was a common victim, resulting in duplicate delivery.
+ Found and investigated by Tim Stewart. Fix by using the open message data
+ file handle rather than opening another, and not locally closing it (which
+ releases a lock) for that case, while creating the temporary .eml format
+ file for the MIME ACL. Also applies to "regex" and "spam" ACL conditions.
+
+JH/07 Bug 177: Make a random-recipient callout success visible in ACL, by setting
+ $sender_verify_failure/$recipient_verify_failure to "random".
+
+JH/08 When generating a selfsigned cert, use serial number 1 since zero is not
+ legitimate.
+
+JH/09 Bug 2274: Fix logging of cmdline args when starting in an unlinked cwd.
+ Previously this would segfault.
+
+JH/10 Fix ARC signing for case when DKIM signing failed. Previously this would
+ segfault.
+
+JH/11 Bug 2264: Exim now only follows CNAME chains one step by default. We'd
+ like zero, since the resolver should be doing this for us, But we need one
+ as a CNAME but no MX presence gets the CNAME returned; we need to check
+ that doesn't point to an MX to declare it "no MX returned" rather than
+ "error, loop". A new main option is added so the older capability of
+ following some limited number of chain links is maintained.
+
+JH/12 Add client-ip info to non-pass iprev ${authres } lines.
+
+JH/13 For receent Openssl versions (1.1 onward) use modern generic protocol
+ methods. These should support TLS 1.3; they arrived with TLS 1.3 and the
+ now-deprecated earlier definitions used only specified the range up to TLS
+ 1.2 (in the older-version library docs).
+
+JH/14 Bug 2284: Fix DKIM signing for body lines starting with a pair of dots.
+
+JH/15 Rework TLS client-side context management. Stop using a global, and
+ explicitly pass a context around. This enables future use of TLS for
+ connections to service-daemons (eg. malware scanning) while a client smtp
+ connection is using TLS; with cutthrough connections this is quite likely.
+
+JH/16 Fix ARC verification to do AS checks in reverse order.
+
+JH/17 Support a "tls" option on the ${readsocket } expansion item.
+
+JH/18 Bug 2287: Fix the protocol name (eg utf8esmtp) for multiple messages
+ using the SMTPUTF8 option on their MAIL FROM commands, in one connection.
+ Previously the "utf8" would be re-prepended for every additional message.
+
+JH/19 Reject MAIL FROM commands with SMTPUTF8 when the facility was not advertised.
+ Previously thery were accepted, resulting in issues when attempting to
+ forward messages to a non-supporting MTA.
+
+PP/02 Let -n work with printing macros too, not just options.
+
+JH/20 Bug 2296: Fix cutthrough for >1 address redirection. Previously only
+ one parent address was copied, and bogus data was used at delivery-logging
+ time. Either a crash (after delivery) or bogus log data could result.
+ Discovery and analysis by Tim Stewart.
+
+PP/03 Make ${utf8clean:} expansion operator detect incomplete final character.
+ Previously if the string ended mid-character, we did not insert the
+ promised '?' replacement.
+
+PP/04 Documentation: current string operators work on bytes, not codepoints.
+
+JH/21 Change as many as possible of the global flags into one-bit bitfields; these
+ should pack well giving a smaller memory footprint so better caching and
+ therefore performance. Group the declarations where this can't be done so
+ that the byte-sized flag variables are not interspersed among pointer
+ variables, giving a better chance of good packing by the compiler.
+
+JH/22 Bug 1896: Fix the envelope from for DMARC forensic reports to be possibly
+ non-null, to avoid issues with sites running BATV. Previously reports were
+ sent with an empty envelope sender so looked like bounces.
+
+JH/23 Bug 2318: Fix the noerror command within filters. It wasn't working.
+ The ignore_error flag wasn't being returned from the filter subprocess so
+ was not set for later routers. Investigation and fix by Matthias Kurz.
+
+JH/24 Bug 2310: Raise a msg:fail:internal event for each undelivered recipient,
+ and a msg:complete for the whole, when a message is manually removed using
+ -Mrm. Developement by Matthias Kurz, hacked on by JH.
+
+JH/25 Avoid fixed-size buffers for pathnames in DB access. This required using
+ a "Gnu special" function, asprintf() in the DB utility binary builds; I
+ hope that is portable enough.
+
+JH/26 Bug 2311: Fix DANE-TA verification under GnuTLS. Previously it was also
+ requiring a known-CA anchor certificate; make it now rely entirely on the
+ TLSA as an anchor. Checking the name on the leaf cert against the name
+ on the A-record for the host is still done for TA (but not for EE mode).
+
+JH/27 Fix logging of proxy address. Previously, a pointless "PRX=[]:0" would be
+ included in delivery lines for non-proxied connections, when compiled with
+ SUPPORT_SOCKS and running with proxy logging enabled.
+
+JH/28 Bug 2314: Fire msg:fail:delivery event even when error is being ignored.
+ Developement by Matthias Kurz, tweaked by JH. While in that bit of code,
+ move the existing event to fire before the normal logging of message
+ failure so that custom logging is bracketed by normal logging.
+
+JH/29 Bug 2322: A "fail" command in a non-system filter (file) now fires the
+ msg:fail:internal event. Developement by Matthias Kurz.
+
+JH/30 Bug 2329: Increase buffer size used for dns lookup from 2k, which was
+ far too small for todays use of crypto signatures stored there. Go all
+ the way to the max DNS message size of 64kB, even though this might be
+ overmuch for IOT constrained device use.
+
+JH/31 Fix a bad use of a copy function, which could be used to pointlessly
+ copy a string over itself. The library routine is documented as not
+ supporting overlapping copies, and on MacOS it actually raised a SIGABRT.
+
+JH/32 For main options check_spool_space and check_inode_space, where the
+ platform supports 64b integers, support more than the previous 2^31 kB
+ (i.e. more than 2 TB). Accept E, P and T multipliers in addition to
+ the previous G, M, k.
+
+JH/33 Bug 2338: Fix the cyrus-sasl authenticator to fill in the
+ $authenticated_fail_id variable on authentication failure. Previously
+ it was unset.
+
+JH/34 Increase RSA keysize of autogen selfsign cert from 1024 to 2048. RHEL 8.0
+ OpenSSL didn't want to use such a weak key. Do for GnuTLS also, and for
+ more-modern GnuTLS move from GNUTLS_SEC_PARAM_LOW to
+ GNUTLS_SEC_PARAM_MEDIUM.
+
+JH/35 OpenSSL: fail the handshake when SNI processing hits a problem, server
+ side. Previously we would continue as if no SNI had been received.
+
+JH/36 Harden the handling of string-lists. When a list consisted of a sole
+ "<" character, which should be a list-separator specification, we walked
+ off past the nul-terimation.
+
+JH/37 Bug 2341: Send "message delayed" warning MDNs (restricted to external
+ causes) even when the retry time is not yet met. Previously they were
+ not, meaning that when (say) an account was over-quota and temp-rejecting,
+ and multiple senders' messages were queued, only one sender would get
+ notified on each configured delay_warning cycle.
+
+JH/38 Bug 2351: Log failures to extract envelope addresses from message headers.
+
+JH/39 OpenSSL: clear the error stack after an SSL_accept(). With anon-auth
+ cipher-suites, an error can be left on the stack even for a succeeding
+ accept; this results in impossible error messages when a later operation
+ actually does fail.
+
+AM/01 Bug 2359: GnuTLS: repeat lowlevel read and write operations while they
+ return error codes indicating retry. Under TLS1.3 this becomes required.
+
+JH/40 Fix the feature-cache refresh for EXPERIMENTAL_PIPE_CONNECT. Previously
+ it only wrote the new authenticators, resulting in a lack of tracking of
+ peer changes of ESMTP extensions until the next cache flush.
+
+JH/41 Fix the loop reading a message header line to check for integer overflow,
+ and more-often against header_maxsize. Previously a crafted message could
+ induce a crash of the recive process; now the message is cleanly rejected.
+
+JH/42 Bug 2366: Fix the behaviour of the dkim_verify_signers option. It had
+ been totally disabled for all of 4.91. Discovery and fix by "Mad Alex".
+
+
Exim version 4.91
-----------------
Previously it was possible to log spurious information in receive log
lines.
+JH/37 Bug 2255: Revert the disable of the OpenSSL session caching. This
+ triggered odd behaviour from Outlook Express clients.
+
+PP/03 Add util/renew-opendmarc-tlds.sh script for safe renewal of public
+ suffix list.
+
+JH/38 DKIM: accept Ed25519 pubkeys in SubjectPublicKeyInfo-wrapped form,
+ since the IETF WG has not yet settled on that versus the original
+ "bare" representation.
+
+JH/39 Fix syslog logging for syslog_timestamp=no and log_selector +millisec.
+ Previously the millisecond value corrupted the output.
+ Fix also for syslog_pid=no and log_selector +pid, for which the pid
+ corrupted the output.
+
Exim version 4.90
-----------------
line, the header hash was calculated to an incorrect value thanks to
the (relaxed) space the fold became.
-HS/02 Fix Bug 2130: large writes from the transport subprocess where chunked
+HS/02 Fix Bug 2130: large writes from the transport subprocess were chunked
and confused the parent.
JH/27 Fix SOCKS bug: an unitialized pointer was deref'd by the transport process
git://git.exim.org / users / jgh / exim.git / blobdiff