New Features in Exim -------------------- This file contains descriptions of new features that have been added to Exim. Before a formal release, there may be quite a lot of detail so that people can test from the snapshots or the CVS before the documentation is updated. Once the documentation is updated, this file is reduced to a short list. Version 4.78 ------------ 1. New authenticator driver, "gsasl". Server-only (at present). This is a SASL interface, licensed under GPL, which can be found at http://www.gnu.org/software/gsasl/. This system does not provide sources of data for authentication, so careful use needs to be made of the conditions in Exim. Note that this can not yet be used as a drop-in replacement for Cyrus SASL, as Exim is currently unable to construct strings with embedded NULs for use as keys in lookups against sasldb2. 2. New authenticator driver, "heimdal_gssapi". Server-only. A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME is no longer honoured for setuid programs by Heimdal. Use the "server_keytab" option to point to the keytab. 3. The "pkg-config" system can now be used when building Exim to reference cflags and library information for lookups and authenticators, rather than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and "LOOKUP_LIBS" directly. Similarly for handling the TLS library support without adjusting "TLS_INCLUDE" and "TLS_LIBS". Version 4.77 ------------ 1. New options for the ratelimit ACL condition: /count= and /unique=. The /noupdate option has been replaced by a /readonly option. 2. The SMTP transport's protocol option may now be set to "smtps", to use SSL-on-connect outbound. 3. New variable $av_failed, set true if the AV scanner deferred; ie, when there is a problem talking to the AV scanner, or the AV scanner running. 4. New expansion conditions, "inlist" and "inlisti", which take simple lists and check if the search item is a member of the list. This does not support named lists, but does subject the list part to string expansion. 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was built, Exim no longer performs string expansion on the second string of the match_* expansion conditions: "match_address", "match_domain", "match_ip" & "match_local_part". Named lists can still be used. Version 4.76 ------------ 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on or off in the resolver library. Version 4.75 ------------ 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there is now LDAP/TLS support, given sufficiently modern OpenLDAP client libraries. The following global options have been added in support of this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key, ldap_cipher_suite, ldap_require_cert, ldap_start_tls. 2. The pipe transport now takes a boolean option, "freeze_signal", default false. When true, if the external delivery command exits on a signal then Exim will freeze the message in the queue, instead of generating a bounce. 3. Log filenames may now use %M as an escape, instead of %D (still available). The %M pattern expands to yyyymm, providing month-level resolution. 4. The $message_linecount variable is now updated for the maildir_tag option, in the same way as $message_size, to reflect the real number of lines, including any header additions or removals from transport. 5. When contacting a pool of SpamAssassin servers configured in spamd_address, Exim now selects entries randomly, to better scale in a cluster setup. Version 4.74 ------------ 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux) the flaw permitted the Exim run-time user to cause root to append to arbitrary files of the attacker's choosing, with the content based on content supplied by the attacker. 2. Exim now supports loading some lookup types at run-time, using your platform's dlopen() functionality. This has limited platform support and the intention is not to support every variant, it's limited to dlopen(). This permits the main Exim binary to not be linked against all the libraries needed for all the lookup types. Version 4.73 ------------ NOTE: this version is not guaranteed backwards-compatible, please read the items below carefully 1. A new main configuration option, "openssl_options", is available if Exim is built with SSL support provided by OpenSSL. The option allows administrators to specify OpenSSL options to be used on connections; typically this is to set bug compatibility features which the OpenSSL developers have not enabled by default. There may be security consequences for certain options, so these should not be changed frivolously. 2. A new pipe transport option, "permit_coredumps", may help with problem diagnosis in some scenarios. Note that Exim is typically installed as a setuid binary, which on most OSes will inhibit coredumps by default, so that safety mechanism would have to be overridden for this option to be able to take effect. 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes Note that this switches Exim to use a new API ("INSTREAM") and a future release of ClamAV will remove support for the old API ("STREAM"). The av_scanner option, when set to "clamd", now takes an optional third part, "local", which causes Exim to pass a filename to ClamAV instead of the file content. This is the same behaviour as when clamd is pointed at a Unix-domain socket. For example: av_scanner = clamd:192.0.2.3 1234:local ClamAV's ExtendedDetectionInfo response format is now handled. 4. There is now a -bmalware option, restricted to admin users. This option takes one parameter, a filename, and scans that file with Exim's malware-scanning framework. This is intended purely as a debugging aid to ensure that Exim's scanning is working, not to replace other tools. Note that the ACL framework is not invoked, so if av_scanner references ACL variables without a fallback then this will fail. 5. There is a new expansion operator, "reverse_ip", which will reverse IP addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples: ${reverse_ip:192.0.2.4} -> 4.2.0.192 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3} -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2 6. There is a new ACL control called "debug", to enable debug logging. This allows selective logging of certain incoming transactions within production environments, with some care. It takes two options, "tag" and "opts"; "tag" is included in the filename of the log and "opts" is used as per the -d command-line option. Examples, which don't all make sense in all contexts: control = debug control = debug/tag=.$sender_host_address control = debug/opts=+expand+acl control = debug/tag=.$message_exim_id/opts=+expand 7. It has always been implicit in the design and the documentation that "the Exim user" is not root. src/EDITME said that using root was "very strongly discouraged". This is not enough to keep people from shooting themselves in the foot in days when many don't configure Exim themselves but via package build managers. The security consequences of running various bits of network code are severe if there should be bugs in them. As such, the Exim user may no longer be root. If configured statically, Exim will refuse to build. If configured as ref:user then Exim will exit shortly after start-up. If you must shoot yourself in the foot, then henceforth you will have to maintain your own local patches to strip the safeties off. 8. There is a new expansion operator, bool_lax{}. Where bool{} uses the ACL condition logic to determine truth/failure and will fail to expand many strings, bool_lax{} uses the router condition logic, where most strings do evaluate true. Note: bool{00} is false, bool_lax{00} is true. 9. Routers now support multiple "condition" tests, 10. There is now a runtime configuration option "tcp_wrappers_daemon_name". Setting this allows an admin to define which entry in the tcpwrappers config file will be used to control access to the daemon. This option is only available when Exim is built with USE_TCP_WRAPPERS. The default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME build option. 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now the Exim run-time user, instead of root. 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and is forced on. This is mitigated by the new build option TRUSTED_CONFIG_LIST which defines a list of configuration files which are trusted; one per line. If a config file is owned by root and matches a pathname in the list, then it may be invoked by the Exim build-time user without Exim relinquishing root privileges. 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically trusted to supply -D overrides on the command-line. Going forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that include the main config. As a transition mechanism, we are temporarily providing a work-around: the new build option WHITELIST_D_MACROS provides a colon-separated list of macro names which may be overridden by the Exim run-time user. The values of these macros are constrained to the regex ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values). Version 4.72 ------------ 1. TWO SECURITY FIXES: one relating to mail-spools which are globally writable, the other to locking of MBX folders (not mbox). 2. MySQL stored procedures are now supported. 3. The dkim_domain transport option is now a list, not a single string, and messages will be signed for each element in the list (discarding duplicates). 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups in the presence of multiple character strings within the RR. Prior to 4.70, only the first string would be returned. The dnsdb lookup now, by default, preserves the pre-4.70 semantics, but also now takes an extended output separator specification. The separator can be followed by a semicolon, to concatenate the individual text strings together with no join character, or by a comma and a second separator character, in which case the text strings within a TXT record are joined on that second character. Administrators are reminded that DNS provides no ordering guarantees between multiple records in an RRset. For example: foo.example. IN TXT "a" "b" "c" foo.example. IN TXT "d" "e" "f" ${lookup dnsdb{>/ txt=foo.example}} -> "a/d" ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc" ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f" Version 4.70 / 4.71 ------------------- 1. Native DKIM support without an external library. (Note that if no action to prevent it is taken, a straight upgrade will result in DKIM verification of all signed incoming emails. See spec for details on conditionally disabling) 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha). 3. There is now a bool{} expansion condition which maps certain strings to true/false condition values (most likely of use in conjunction with the and{} expansion operator). 4. The $spam_score, $spam_bar and $spam_report variables are now available at delivery time. 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as options, provided that Exim is invoked by an admin_user. 6. There is a new option gnutls_compat_mode, when linked against GnuTLS, which increases compatibility with older clients at the cost of decreased security. Don't set this unless you need to support such clients. 7. There is a new expansion operator, ${randint:...} which will produce a "random" number less than the supplied integer. This randomness is not guaranteed to be cryptographically strong, but depending upon how Exim was built may be better than the most naive schemes. 8. Exim now explicitly ensures that SHA256 is available when linked against OpenSSL. 9. The transport_filter_timeout option now applies to SMTP transports too. Version 4.69 ------------ 1. Preliminary DKIM support in Experimental. Version 4.68 ------------ 1. The body_linecount and body_zerocount C variables are now exported in the local_scan API. 2. When a dnslists lookup succeeds, the key that was looked up is now placed in $dnslist_matched. When the key is an IP address, it is not reversed in this variable (though it is, of course, in the actual lookup). In simple cases, for example: deny dnslists = spamhaus.example the key is also available in another variable (in this case, $sender_host_address). In more complicated cases, however, this is not true. For example, using a data lookup might generate a dnslists lookup like this: deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|... If this condition succeeds, the value in $dnslist_matched might be 192.168.6.7 (for example). 3. Authenticators now have a client_condition option. When Exim is running as a client, it skips an authenticator whose client_condition expansion yields "0", "no", or "false". This can be used, for example, to skip plain text authenticators when the connection is not encrypted by a setting such as: client_condition = ${if !eq{$tls_cipher}{}} Note that the 4.67 documentation states that $tls_cipher contains the cipher used for incoming messages. In fact, during SMTP delivery, it contains the cipher used for the delivery. The same is true for $tls_peerdn. 4. There is now a -Mvc option, which outputs a copy of the message to the standard output, in RFC 2822 format. The option can be used only by an admin user. 5. There is now a /noupdate option for the ratelimit ACL condition. It computes the rate and checks the limit as normal, but it does not update the saved data. This means that, in relevant ACLs, it is possible to lookup the existence of a specified (or auto-generated) ratelimit key without incrementing the ratelimit counter for that key. In order for this to be useful, another ACL entry must set the rate for the same key somewhere (otherwise it will always be zero). Example: acl_check_connect: # Read the rate; if it doesn't exist or is below the maximum # we update it below deny ratelimit = 100 / 5m / strict / noupdate log_message = RATE: $sender_rate / $sender_rate_period \ (max $sender_rate_limit) [... some other logic and tests...] warn ratelimit = 100 / 5m / strict / per_cmd log_message = RATE UPDATE: $sender_rate / $sender_rate_period \ (max $sender_rate_limit) condition = ${if le{$sender_rate}{$sender_rate_limit}} accept 6. The variable $max_received_linelength contains the number of bytes in the longest line that was received as part of the message, not counting the line termination character(s). 7. Host lists can now include +ignore_defer and +include_defer, analagous to +ignore_unknown and +include_unknown. These options should be used with care, probably only in non-critical host lists such as whitelists. 8. There's a new option called queue_only_load_latch, which defaults true. If set false when queue_only_load is greater than zero, Exim re-evaluates the load for each incoming message in an SMTP session. Otherwise, once one message is queued, the remainder are also. 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most cases when an SMTP session ends without sending QUIT. However, when Exim itself is is bad trouble, such as being unable to write to its log files, this ACL is not run, because it might try to do things (such as write to log files) that make the situation even worse. Like the QUIT ACL, this new ACL is provided to make it possible to gather statistics. Whatever it returns (accept or deny) is immaterial. The "delay" modifier is forbidden in this ACL. When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set to a string that indicates the reason for the termination of the SMTP connection. The possible values are: acl-drop Another ACL issued a "drop" command bad-commands Too many unknown or non-mail commands command-timeout Timeout while reading SMTP commands connection-lost The SMTP connection has been lost data-timeout Timeout while reading message data local-scan-error The local_scan() function crashed local-scan-timeout The local_scan() function timed out signal-exit SIGTERM or SIGINT synchronization-error SMTP synchronization error tls-failed TLS failed to start In most cases when an SMTP connection is closed without having received QUIT, Exim sends an SMTP response message before actually closing the connection. With the exception of acl-drop, the default message can be overridden by the "message" modifier in the NOTQUIT ACL. In the case of a "drop" verb in another ACL, it is the message from the other ACL that is used. 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of servers with individual queries. This is done by starting the query with "servers=x:y:z;", where each item in the list may take one of two forms: (1) If it is just a host name, the appropriate global option (mysql_servers or pgsql_servers) is searched for a host of the same name, and the remaining parameters (database, user, password) are taken from there. (2) If it contains any slashes, it is taken as a complete parameter set. The list of servers is used in exactly the same was as the global list. Once a connection to a server has happened and a query has been successfully executed, processing of the lookup ceases. This feature is intended for use in master/slave situations where updates are occurring, and one wants to update a master rather than a slave. If the masters are in the list for reading, you might have: mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw In an updating lookup, you could then write ${lookup mysql{servers=master; UPDATE ...} If, on the other hand, the master is not to be used for reading lookups: pgsql_servers = slave1/db/name/pw:slave2/db/name/pw you can still update the master by ${lookup pgsql{servers=master/db/name/pw; UPDATE ...} 11. The message_body_newlines option (default FALSE, for backwards compatibility) can be used to control whether newlines are present in $message_body and $message_body_end. If it is FALSE, they are replaced by spaces. Version 4.67 ------------ 1. There is a new log selector called smtp_no_mail, which is not included in the default setting. When it is set, a line is written to the main log whenever an accepted SMTP connection terminates without having issued a MAIL command. 2. When an item in a dnslists list is followed by = and & and a list of IP addresses, the behaviour was not clear when the lookup returned more than one IP address. This has been solved by the addition of == and =& for "all" rather than the default "any" matching. 3. Up till now, the only control over which cipher suites GnuTLS uses has been for the cipher algorithms. New options have been added to allow some of the other parameters to be varied. 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is set, Exim compiles a runtime option called disable_fsync. 5. There is a new variable called $smtp_count_at_connection_start. 6. There's a new control called no_pipelining. 7. There are two new variables called $sending_ip_address and $sending_port. These are set whenever an SMTP connection to another host has been set up. 8. The expansion of the helo_data option in the smtp transport now happens after the connection to the server has been made. 9. There is a new expansion operator ${rfc2047d: that decodes strings that are encoded as per RFC 2047. 10. There is a new log selector called "pid", which causes the current process id to be added to every log line, in square brackets, immediately after the time and date. 11. Exim has been modified so that it flushes SMTP output before implementing a delay in an ACL. It also flushes the output before performing a callout, as this can take a substantial time. These behaviours can be disabled by obeying control = no_delay_flush or control = no_callout_flush, respectively, at some earlier stage of the connection. 12. There are two new expansion conditions that iterate over a list. They are called forany and forall. 13. There's a new global option called dsn_from that can be used to vary the contents of From: lines in bounces and other automatically generated messages ("delivery status notifications" - hence the name of the option). 14. The smtp transport has a new option called hosts_avoid_pipelining. 15. By default, exigrep does case-insensitive matches. There is now a -I option that makes it case-sensitive. 16. A number of new features ("addresses", "map", "filter", and "reduce") have been added to string expansions to make it easier to process lists of items, typically addresses. 17. There's a new ACL modifier called "continue". It does nothing of itself, and processing of the ACL always continues with the next condition or modifier. It is provided so that the side effects of expanding its argument can be used. 18. It is now possible to use newline and other control characters (those with values less than 32, plus DEL) as separators in lists. 19. The exigrep utility now has a -v option, which inverts the matching condition. 20. The host_find_failed option in the manualroute router can now be set to "ignore". Version 4.66 ------------ No new features were added to 4.66. Version 4.65 ------------ No new features were added to 4.65. Version 4.64 ------------ 1. ACL variables can now be given arbitrary names, as long as they start with "acl_c" or "acl_m" (for connection variables and message variables), are at least six characters long, with the sixth character being either a digit or an underscore. 2. There is a new ACL modifier called log_reject_target. It makes it possible to specify which logs are used for messages about ACL rejections. 3. There is a new authenticator called "dovecot". This is an interface to the authentication facility of the Dovecot POP/IMAP server, which can support a number of authentication methods. 4. The variable $message_headers_raw provides a concatenation of all the messages's headers without any decoding. This is in contrast to $message_headers, which does RFC2047 decoding on the header contents. 5. In a DNS black list, if two domain names, comma-separated, are given, the second is used first to do an initial check, making use of any IP value restrictions that are set. If there is a match, the first domain is used, without any IP value restrictions, to get the TXT record. 6. All authenticators now have a server_condition option. 7. There is a new command-line option called -Mset. It is useful only in conjunction with -be (that is, when testing string expansions). It must be followed by a message id; Exim loads the given message from its spool before doing the expansions. 8. Another similar new command-line option is called -bem. It operates like -be except that it must be followed by the name of a file that contains a message. 9. When an address is delayed because of a 4xx response to a RCPT command, it is now the combination of sender and recipient that is delayed in subsequent queue runs until its retry time is reached. 10. Unary negation and the bitwise logical operators and, or, xor, not, and shift, have been added to the eval: and eval10: expansion items. 11. The variables $interface_address and $interface_port have been renamed as $received_ip_address and $received_port, to make it clear that they relate to message reception rather than delivery. (The old names remain available for compatibility.) 12. The "message" modifier can now be used on "accept" and "discard" acl verbs to vary the message that is sent when an SMTP command is accepted. Version 4.63 ------------ 1. There is a new Boolean option called filter_prepend_home for the redirect router. 2. There is a new acl, set by acl_not_smtp_start, which is run right at the start of receiving a non-SMTP message, before any of the message has been read. 3. When an SMTP error message is specified in a "message" modifier in an ACL, or in a :fail: or :defer: message in a redirect router, Exim now checks the start of the message for an SMTP error code. 4. There is a new parameter for LDAP lookups called "referrals", which takes one of the settings "follow" (the default) or "nofollow". 5. Version 20070721.2 of exipick now included, offering these new options: --reverse After all other sorting options have bee processed, reverse order before displaying messages (-R is synonym). --random Randomize order of matching messages before displaying. --size Instead of displaying the matching messages, display the sum of their sizes. --sort [,...] Before displaying matching messages, sort the messages according to each messages value for each variable. --not Negate the value for every test (returns inverse output from the same criteria without --not). Version 4.62 ------------ 1. The ${readsocket expansion item now supports Internet domain sockets as well as Unix domain sockets. If the first argument begins "inet:", it must be of the form "inet:host:port". The port is mandatory; it may be a number or the name of a TCP port in /etc/services. The host may be a name, or it may be an IP address. An ip address may optionally be enclosed in square brackets. This is best for IPv6 addresses. For example: ${readsocket{inet:[::1]:1234}{}... Only a single host name may be given, but if looking it up yield more than one IP address, they are each tried in turn until a connection is made. Once a connection has been made, the behaviour is as for ${readsocket with a Unix domain socket. 2. If a redirect router sets up file or pipe deliveries for more than one incoming address, and the relevant transport has batch_max set greater than one, a batch delivery now occurs. 3. The appendfile transport has a new option called maildirfolder_create_regex. Its value is a regular expression. For a maildir delivery, this is matched against the maildir directory; if it matches, Exim ensures that a maildirfolder file is created alongside the new, cur, and tmp directories. Version 4.61 ------------ The documentation is up-to-date for the 4.61 release. Major new features since the 4.60 release are: . An option called disable_ipv6, to disable the use of IPv6 completely. . An increase in the number of ACL variables to 20 of each type. . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1, $2, $3, (though those are still set) because the numeric variables get used for other things in complicated expansions. . The default for rfc1413_query_timeout has been changed from 30s to 5s. . It is possible to use setclassresources() on some BSD OS to control the resources used in pipe deliveries. . A new ACL modifier called add_header, which can be used with any verb. . More errors are detectable in retry rules. There are a number of other additions too. Version 4.60 ------------ The documentation is up-to-date for the 4.60 release. Major new features since the 4.50 release are: . Support for SQLite. . Support for IGNOREQUOTA in LMTP. . Extensions to the "submission mode" features. . Support for Client SMTP Authorization (CSA). . Support for ratelimiting hosts and users. . New expansion items to help with the BATV "prvs" scheme. . A "match_ip" condition, that matches an IP address against a list. There are many more minor changes. ****