X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/4a65a58d21383c16258b669f57beddb4742fbb9b..6d8e1b63fda70bb4153034870cc8b68f9011d0e1:/doc/doc-docbook/spec.xfpt
diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index e07c7a16f..eafd56fba 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -45,7 +45,7 @@
. Update the Copyright year (only) when changing content.
. /////////////////////////////////////////////////////////////////////////////
-.set previousversion "4.94"
+.set previousversion "4.95"
.include ./local_params
.set ACL "access control lists (ACLs)"
@@ -54,7 +54,7 @@
.set drivernamemax "64"
.macro copyyear
-2020
+2022
.endmacro
. /////////////////////////////////////////////////////////////////////////////
@@ -97,6 +97,21 @@
.itable none 0 0 2 $1 left $2 left
.endmacro
+
+. --- A macro for a "tainted" marker, done as a one-element table
+.macro tmark
+.itable none 0 0 1 10pt left
+.row &'Tainted'&
+.endtable
+.endmacro
+. --- A macro for a tainted variable, adding a taint-marker
+. --- and including the .vitem and .vindex
+.macro tvar
+.vitem $1
+.vindex $1
+.tmark
+.endmacro
+
. --- A macro that generates .row, but puts &I; at the start of the first
. --- argument, thus indenting it. Assume a minimum of two arguments, and
. --- allow up to four arguments, which is as many as we'll ever need.
@@ -193,7 +208,7 @@
.copyyear
- University of Cambridge
+ The Exim Maintainers
.literal off
@@ -239,14 +254,6 @@
failure report
bounce message
-
- de-tainting
- tainting, de-tainting
-
-
- detainting
- tainting, de-tainting
-
dialup
intermittently connected hosts
@@ -766,17 +773,17 @@ the Exim documentation, &"spool"& is always used in the first sense.
.chapter "Incorporated code" "CHID2"
.cindex "incorporated code"
.cindex "regular expressions" "library"
-.cindex "PCRE"
+.cindex "PCRE2"
.cindex "OpenDMARC"
A number of pieces of external code are included in the Exim distribution.
.ilist
Regular expressions are supported in the main Exim program and in the
-Exim monitor using the freely-distributable PCRE library, copyright
-© University of Cambridge. The source to PCRE is no longer shipped with
-Exim, so you will need to use the version of PCRE shipped with your system,
+Exim monitor using the freely-distributable PCRE2 library, copyright
+© University of Cambridge. The source to PCRE2 is not longer shipped with
+Exim, so you will need to use the version of PCRE2 shipped with your system,
or obtain and install the full version of the library from
-&url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre).
+&url(https://github.com/PhilipHazel/pcre2/releases).
.next
.cindex "cdb" "acknowledgment"
Support for the cdb (Constant DataBase) lookup method is provided by code
@@ -1421,8 +1428,8 @@ check an address given in the SMTP EXPN command (see the &%expn%& option).
.next
If the &%domains%& option is set, the domain of the address must be in the set
of domains that it defines.
-.new
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using router domains option"
A match verifies the variable &$domain$& (which carries tainted data)
and assigns an untainted value to the &$domain_data$& variable.
Such an untainted value is often needed in the transport.
@@ -1431,7 +1438,6 @@ refer to section &<>&.
When an untainted value is wanted, use this option
rather than the generic &%condition%& option.
-.wen
.next
.vindex "&$local_part_prefix$&"
@@ -1442,7 +1448,6 @@ rather than the generic &%condition%& option.
.cindex affix "router precondition"
If the &%local_parts%& option is set, the local part of the address must be in
the set of local parts that it defines.
-.new
A match verifies the variable &$local_part$& (which carries tainted data)
and assigns an untainted value to the &$local_part_data$& variable.
Such an untainted value is often needed in the transport.
@@ -1451,7 +1456,6 @@ refer to section &<>&.
When an untainted value is wanted, use this option
rather than the generic &%condition%& option.
-.wen
If &%local_part_prefix%& or
&%local_part_suffix%& is in use, the prefix or suffix is removed from the local
@@ -1492,7 +1496,6 @@ If the &%condition%& option is set, it is evaluated and tested. This option
uses an expanded string to allow you to set up your own custom preconditions.
Expanded strings are described in chapter &<>&.
-.new
Note that while using
this option for address matching technically works,
it does not set any de-tainted values.
@@ -1500,7 +1503,6 @@ Such values are often needed, either for router-specific options or
for transport options.
Using the &%domains%& and &%local_parts%& options is usually the most
convenient way to obtain them.
-.wen
.endlist
@@ -1751,20 +1753,20 @@ overridden if necessary.
A C99-capable compiler will be required for the build.
-.section "PCRE library" "SECTpcre"
-.cindex "PCRE library"
-Exim no longer has an embedded PCRE library as the vast majority of
-modern systems include PCRE as a system library, although you may need to
-install the PCRE package or the PCRE development package for your operating
-system. If your system has a normal PCRE installation the Exim build
+.section "PCRE2 library" "SECTpcre"
+.cindex "PCRE2 library"
+Exim no longer has an embedded regular-expression library as the vast majority of
+modern systems include PCRE2 as a system library, although you may need to
+install the PCRE2 package or the PCRE2 development package for your operating
+system. If your system has a normal PCRE2 installation the Exim build
process will need no further configuration. If the library or the
-headers are in an unusual location you will need to either set the PCRE_LIBS
+headers are in an unusual location you will need to either set the PCRE2_LIBS
and INCLUDE directives appropriately,
-or set PCRE_CONFIG=yes to use the installed &(pcre-config)& command.
+or set PCRE2_CONFIG=yes to use the installed &(pcre-config)& command.
If your operating system has no
-PCRE support then you will need to obtain and build the current PCRE
-from &url(ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/).
-More information on PCRE is available at &url(https://www.pcre.org/).
+PCRE2 support then you will need to obtain and build the current PCRE2
+from &url(https://github.com/PhilipHazel/pcre2/releases).
+More information on PCRE2 is available at &url(https://www.pcre.org/).
.section "DBM libraries" "SECTdb"
.cindex "DBM libraries" "discussion of"
@@ -1817,9 +1819,13 @@ the traditional &'ndbm'& interface.
.next
To complicate things further, there are several very different versions of the
Berkeley DB package. Version 1.85 was stable for a very long time, releases
-2.&'x'& and 3.&'x'& were current for a while, but the latest versions when Exim last revamped support were numbered 4.&'x'&.
-Maintenance of some of the earlier releases has ceased. All versions of
-Berkeley DB could be obtained from
+2.&'x'& and 3.&'x'& were current for a while,
+.new
+but the latest versions when Exim last revamped support were numbered 5.&'x'&.
+Maintenance of some of the earlier releases has ceased,
+and Exim no longer supports versions before 3.&'x'&.
+.wen
+All versions of Berkeley DB could be obtained from
&url(http://www.sleepycat.com/), which is now a redirect to their new owner's
page with far newer versions listed.
It is probably wise to plan to move your storage configurations away from
@@ -1843,6 +1849,9 @@ USE_DB=yes
.endd
Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
error is diagnosed if you set more than one of these.
+.new
+You can set USE_NDBM if needed to override an operating system default.
+.wen
At the lowest level, the build-time configuration sets none of these options,
thereby assuming an interface of type (1). However, some operating system
@@ -1857,7 +1866,11 @@ in one of these lines:
.code
DBMLIB = -ldb
DBMLIB = -ltdb
+DBMLIB = -lgdbm -lgdbm_compat
.endd
+.new
+The last of those was for a Linux having GDBM provide emulated NDBM facilities.
+.wen
Settings like that will work if the DBM library is installed in the standard
place. Sometimes it is not, and the library's header file may also not be in
the default path. You may need to set INCLUDE to specify where the header
@@ -2593,6 +2606,25 @@ use of Exim's filtering capabilities, you should make the document entitled
+.section "Running the daemon" SECTdaemonLaunch
+The most common command line for launching the Exim daemon looks like
+.code
+exim -bd -q5m
+.endd
+This starts a daemon which
+.ilist
+listens for incoming smtp connections, launching handler processes for
+each new one
+.next
+starts a queue-runner process every five minutes, to inspect queued messages
+and run delivery attempts on any that have arrived at their retry time
+.endlist
+Should a queue run take longer than the time between queue-runner starts,
+they will run in parallel.
+Numbers of jobs of the various types are subject to policy controls
+defined in the configuration.
+
+
.section "Upgrading Exim" "SECID36"
.cindex "upgrading Exim"
If you are already running Exim on your host, building and installing a new
@@ -3676,41 +3708,41 @@ of debugging data, respectively. For example, &%-d+filter%& adds filter
debugging, whereas &%-d-all+filter%& selects only filter debugging. Note that
no spaces are allowed in the debug setting. The available debugging categories
are:
-.display
-&`acl `& ACL interpretation
-&`auth `& authenticators
-&`deliver `& general delivery logic
-&`dns `& DNS lookups (see also resolver)
-&`dnsbl `& DNS black list (aka RBL) code
-&`exec `& arguments for &[execv()]& calls
-&`expand `& detailed debugging for string expansions
-&`filter `& filter handling
-&`hints_lookup `& hints data lookups
-&`host_lookup `& all types of name-to-IP address handling
-&`ident `& ident lookup
-&`interface `& lists of local interfaces
-&`lists `& matching things in lists
-&`load `& system load checks
-&`local_scan `& can be used by &[local_scan()]& (see chapter &&&
- &<>&)
-&`lookup `& general lookup code and all lookups
-&`memory `& memory handling
-&`noutf8 `& modifier: avoid UTF-8 line-drawing
-&`pid `& modifier: add pid to debug output lines
-&`process_info `& setting info for the process log
-&`queue_run `& queue runs
-&`receive `& general message reception logic
-&`resolver `& turn on the DNS resolver's debugging output
-&`retry `& retry handling
-&`rewrite `& address rewriting
-&`route `& address routing
-&`timestamp `& modifier: add timestamp to debug output lines
-&`tls `& TLS logic
-&`transport `& transports
-&`uid `& changes of uid/gid and looking up uid/gid
-&`verify `& address verification logic
-&`all `& almost all of the above (see below), and also &%-v%&
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow acl "ACL interpretation"
+.irow auth "authenticators"
+.irow deliver "general delivery logic"
+.irow dns "DNS lookups (see also resolver)"
+.irow dnsbl "DNS black list (aka RBL) code"
+.irow exec "arguments for &[execv()]& calls"
+.irow expand "detailed debugging for string expansions"
+.irow filter "filter handling"
+.irow hints_lookup "hints data lookups"
+.irow host_lookup "all types of name-to-IP address handling"
+.irow ident "ident lookup"
+.irow interface "lists of local interfaces"
+.irow lists "matching things in lists"
+.irow load "system load checks"
+.irow local_scan "can be used by &[local_scan()]& (see chapter &&&
+ &<>&)"
+.irow lookup "general lookup code and all lookups"
+.irow memory "memory handling"
+.irow noutf8 "modifier: avoid UTF-8 line-drawing"
+.irow pid "modifier: add pid to debug output lines"
+.irow process_info "setting info for the process log"
+.irow queue_run "queue runs"
+.irow receive "general message reception logic"
+.irow resolver "turn on the DNS resolver's debugging output"
+.irow retry "retry handling"
+.irow rewrite "address rewriting""
+.irow route "address routing"
+.irow timestamp "modifier: add timestamp to debug output lines"
+.irow tls "TLS logic"
+.irow transport "transports"
+.irow uid "changes of uid/gid and looking up uid/gid"
+.irow verify "address verification logic"
+.irow all "almost all of the above (see below), and also &%-v%&"
+.endtable
The &`all`& option excludes &`memory`& when used as &`+all`&, but includes it
for &`-all`&. The reason for this is that &`+all`& is something that people
tend to use when generating debug output for Exim maintainers. If &`+memory`&
@@ -3952,7 +3984,6 @@ This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that a
remote host supports the ESMTP &_CHUNKING_& extension.
-.new
.vitem &%-MCL%&
.oindex "&%-MCL%&"
This option is not intended for use by external callers. It is used internally
@@ -3960,7 +3991,6 @@ by Exim in conjunction with the &%-MC%& option. It signifies that the server to
which Exim is connected advertised limits on numbers of mails, recipients or
recipient domains.
The limits are given by the following three arguments.
-.wen
.vitem &%-MCP%&
.oindex "&%-MCP%&"
@@ -3968,14 +3998,12 @@ This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that the server to
which Exim is connected supports pipelining.
-.new
.vitem &%-MCp%&
.oindex "&%-MCp%&"
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that the connection
t a remote server is via a SOCKS proxy, using addresses and ports given by
the following four arguments.
-.wen
.vitem &%-MCQ%&&~<&'process&~id'&>&~<&'pipe&~fd'&>
.oindex "&%-MCQ%&"
@@ -3986,12 +4014,10 @@ together with the file descriptor number of an open pipe. Closure of the pipe
signals the final completion of the sequence of processes that are passing
messages through the same SMTP connection.
-.new
.vitem &%-MCq%&&~<&'recipient&~address'&>&~<&'size'&>
.oindex "&%-MCq%&"
This option is not intended for use by external callers. It is used internally
by Exim to implement quota checking for local users.
-.wen
.vitem &%-MCS%&
.oindex "&%-MCS%&"
@@ -4006,7 +4032,6 @@ This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
host to which Exim is connected supports TLS encryption.
-.new
.vitem &%-MCr%&&~<&'SNI'&> &&&
&%-MCs%&&~<&'SNI'&>
.oindex "&%-MCs%&"
@@ -4016,7 +4041,6 @@ by Exim in conjunction with the &%-MCt%& option, and passes on the fact that
a TLS Server Name Indication was sent as part of the channel establishment.
The argument gives the SNI string.
The "r" variant indicates a DANE-verified connection.
-.wen
.vitem &%-MCt%&&~<&'IP&~address'&>&~<&'port'&>&~<&'cipher'&>
.oindex "&%-MCt%&"
@@ -4538,7 +4562,6 @@ of the syntax, and how it interacts with configuration file options, are given
in chapter &<>&. When &%-oX%& is used to start a daemon, no pid
file is written unless &%-oP%& is also present to specify a pid filename.
-.new
.vitem &%-oY%&
.oindex &%-oY%&
.cindex "daemon notifier socket"
@@ -4557,7 +4580,6 @@ fast ramp-up of queue runner processes
.next
obtaining a current queue size
.endlist
-.wen
.vitem &%-pd%&
.oindex "&%-pd%&"
@@ -6651,9 +6673,9 @@ Chapter &<>& covers both.
.chapter "Regular expressions" "CHAPregexp"
.cindex "regular expressions" "library"
-.cindex "PCRE"
+.cindex "PCRE2"
Exim supports the use of regular expressions in many of its options. It
-uses the PCRE regular expression library; this provides regular expression
+uses the PCRE2 regular expression library; this provides regular expression
matching that is compatible with Perl 5. The syntax and semantics of
regular expressions is discussed in
online Perl manpages, in
@@ -6665,10 +6687,10 @@ O'Reilly (see &url(http://www.oreilly.com/catalog/regex2/)).
. --- to the old URL for now. 2018-09-07.
The documentation for the syntax and semantics of the regular expressions that
-are supported by PCRE is included in the PCRE distribution, and no further
-description is included here. The PCRE functions are called from Exim using
-the default option settings (that is, with no PCRE options set), except that
-the PCRE_CASELESS option is set when the matching is required to be
+are supported by PCRE2 is included in the PCRE2 distribution, and no further
+description is included here. The PCRE2 functions are called from Exim using
+the default option settings (that is, with no PCRE2 options set), except that
+the PCRE2_CASELESS option is set when the matching is required to be
case-insensitive.
In most cases, when a regular expression is required in an Exim configuration,
@@ -6752,6 +6774,9 @@ domains = ${lookup{$sender_host_address}lsearch{/some/file}}
domains = lsearch;/some/file
.endd
The first uses a string expansion, the result of which must be a domain list.
+.new
+The key for an expansion-style lookup must be given explicitly.
+.wen
No strings have been specified for a successful or a failing lookup; the
defaults in this case are the looked-up data and an empty string, respectively.
The expansion takes place before the string is processed as a list, and the
@@ -6763,6 +6788,7 @@ file that is searched could contain lines like this:
When the lookup succeeds, the result of the expansion is a list of domains (and
possibly other types of item that are allowed in domain lists).
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using a lookup expansion""
The result of the expansion is not tainted.
In the second example, the lookup is a single item in a domain list. It causes
@@ -6776,6 +6802,12 @@ domain2:
Any data that follows the keys is not relevant when checking that the domain
matches the list item.
+.new
+The key for a list-style lookup is implicit, from the lookup context, if
+the lookup is a single-key type (see below).
+For query-style lookup types the key must be given explicitly.
+.wen
+
It is possible, though no doubt confusing, to use both kinds of lookup at once.
Consider a file containing lines like this:
.code
@@ -6785,7 +6817,6 @@ If the value of &$sender_host_address$& is 192.168.5.6, expansion of the
first &%domains%& setting above generates the second setting, which therefore
causes a second lookup to occur.
-.new
The lookup type may optionally be followed by a comma
and a comma-separated list of options.
Each option is a &"name=value"& pair.
@@ -6795,7 +6826,6 @@ All lookups support the option &"cache=no_rd"&.
If this is given then the cache that Exim manages for lookup results
is not checked before doing the lookup.
The result of the lookup is still written to the cache.
-.wen
The rest of this chapter describes the different lookup types that are
available. Any of them can be used in any part of the configuration where a
@@ -6812,20 +6842,26 @@ The &'single-key'& type requires the specification of a file in which to look,
and a single key to search for. The key must be a non-empty string for the
lookup to succeed. The lookup type determines how the file is searched.
.cindex "tainted data" "single-key lookups"
-The file string may not be tainted
+The file string may not be tainted.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using a single-key lookup"
All single-key lookups support the option &"ret=key"&.
If this is given and the lookup
(either underlying implementation or cached value)
returns data, the result is replaced with a non-tainted
version of the lookup key.
-.cindex "tainted data" "de-tainting"
.next
.cindex "query-style lookup" "definition of"
The &'query-style'& type accepts a generalized database query. No particular
key value is assumed by Exim for query-style lookups. You can use whichever
Exim variables you need to construct the database query.
+.cindex "tainted data" "quoting for lookups"
+.new
+If tainted data is used in the query then it should be quuted by
+using the &*${quote_*&<&'lookup-type'&>&*:*&<&'string'&>&*}*& expansion operator
+appropriate for the lookup.
+.wen
.endlist
The code for each lookup type is in a separate source file that is included in
@@ -6978,11 +7014,9 @@ the implicit key is the host's IP address rather than its name (see section
IPv4, in dotted-quad form. (Exim converts IPv4-mapped IPv6 addresses to this
notation before executing the lookup.)
-.new
One option is supported, "ret=full", to request the return of the entire line
-rather than omitting the key porttion.
+rather than omitting the key portion.
Note however that the key portion will have been de-quoted.
-.wen
.next
.cindex lookup json
@@ -7003,7 +7037,6 @@ is returned.
For elements of type string, the returned value is de-quoted.
-.new
.next
.cindex LMDB
.cindex lookup lmdb
@@ -7021,7 +7054,6 @@ To enable LMDB support in Exim set LOOKUP_LMDB=yes in &_Local/Makefile_&.
You will need to separately create the LMDB database file,
possibly using the &"mdb_load"& utility.
-.wen
.next
@@ -7423,11 +7455,9 @@ lookups. However, because (apart from the daemon) Exim operates as a collection
of independent, short-lived processes, this caching applies only within a
single Exim process. There is no inter-process lookup caching facility.
-.new
If an option &"cache=no_rd"& is used on the lookup then
the cache is only written to, cached data is not used for the operation
and a real lookup is done.
-.wen
For single-key lookups, Exim keeps the relevant files open in case there is
another lookup that needs them. In some types of configuration this can lead to
@@ -7896,16 +7926,16 @@ be preceded by any number of <&'name'&>=<&'value'&> settings, separated by
spaces. If a value contains spaces it must be enclosed in double quotes, and
when double quotes are used, backslash is interpreted in the usual way inside
them. The following names are recognized:
-.display
-&`DEREFERENCE`& set the dereferencing parameter
-&`NETTIME `& set a timeout for a network operation
-&`USER `& set the DN, for authenticating the LDAP bind
-&`PASS `& set the password, likewise
-&`REFERRALS `& set the referrals parameter
-&`SERVERS `& set alternate server list for this query only
-&`SIZE `& set the limit for the number of entries returned
-&`TIME `& set the maximum waiting time for a query
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow DEREFERENCE "set the dereferencing parameter"
+.irow NETTIME "set a timeout for a network operation"
+.irow USER "set the DN, for authenticating the LDAP bind"
+.irow PASS "set the password, likewise"
+.irow REFERRALS "set the referrals parameter"
+.irow SERVERS "set alternate server list for this query only"
+.irow SIZE "set the limit for the number of entries returned"
+.irow TIME "set the maximum waiting time for a query"
+.endtable
The value of the DEREFERENCE parameter must be one of the words &"never"&,
&"searching"&, &"finding"&, or &"always"&. The value of the REFERRALS parameter
must be &"follow"& (the default) or &"nofollow"&. The latter stops the LDAP
@@ -8285,7 +8315,6 @@ SQLite is different to the other SQL lookups because a filename is required in
addition to the SQL query. An SQLite database is a single file, and there is no
daemon as in the other SQL databases.
-.new
.oindex &%sqlite_dbfile%&
There are two ways of
specifying the file.
@@ -8295,7 +8324,6 @@ is to use an option appended, comma-separated, to the &"sqlite"&
lookup type word. The option is the word &"file"&, then an equals,
then the filename.
The filename in this case cannot contain whitespace or open-brace charachters.
-.wen
A deprecated method is available, prefixing the query with the filename
separated by white space.
@@ -8519,10 +8547,8 @@ will store a result in the &$host_data$& variable.
A &%local_parts%& router option or &%local_parts%& ACL condition
will store a result in the &$local_part_data$& variable.
.vitem domains
-.new
A &%domains%& router option or &%domains%& ACL condition
will store a result in the &$domain_data$& variable.
-.wen
.vitem senders
A &%senders%& router option or &%senders%& ACL condition
will store a result in the &$sender_data$& variable.
@@ -8824,14 +8850,13 @@ or a &%domains%& condition in an ACL statement, the value is preserved in the
&$domain_data$& variable and can be referred to in other router options or
other statements in the same ACL.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using ACL domains condition"
The value will be untainted.
-.new
&*Note*&: If the data result of the lookup (as opposed to the key)
is empty, then this empty value is stored in &$domain_data$&.
The option to return the key for the lookup, as the value,
may be what is wanted.
-.wen
.next
@@ -8867,6 +8892,7 @@ whether or not the query succeeds. However, when a lookup is used for the
&%domains%& option on a router, the value is preserved in the &$domain_data$&
variable and can be referred to in other options.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using router domains option"
The value will be untainted.
.next
@@ -9618,13 +9644,8 @@ reasons,
.cindex "tainted data" definition
.cindex expansion "tainted data"
and expansion of data deriving from the sender (&"tainted data"&)
-.new
is not permitted (including acessing a file using a tainted name).
-The main config option &%allow_insecure_tainted_data%& can be used as
-mitigation during uprades to more secure configurations.
-.wen
-.new
Common ways of obtaining untainted equivalents of variables with
tainted values
.cindex "tainted data" "de-tainting"
@@ -9633,7 +9654,6 @@ This database could be the filesystem structure,
or the password file,
or accessed via a DBMS.
Specific methods are indexed under &"de-tainting"&.
-.wen
@@ -10346,7 +10366,6 @@ extracted is used.
You can use &`fail`& instead of {<&'string3'&>} as in a string extract.
-.new
.vitem &*${listquote{*&<&'separator'&>&*}{*&<&'string'&>&*}}*&
.cindex quoting "for list"
.cindex list quoting
@@ -10355,7 +10374,6 @@ in the given string.
An empty string is replaced with a single space.
This converts the string into a safe form for use as a list element,
in a list using the given separator.
-.wen
.vitem "&*${lookup&~{*&<&'key'&>&*}&~*&<&'search&~type'&>&*&~&&&
@@ -10592,7 +10610,7 @@ sending the request. Values are &"yes"& (the default) or &"no"&
&*tls*&
Controls the use of TLS on the connection.
Values are &"yes"& or &"no"& (the default).
-If it is enabled, a shutdown as descripbed above is never done.
+If it is enabled, a shutdown as described above is never done.
.endlist
@@ -10664,16 +10682,32 @@ expansion items.
This item inserts &"raw"& header lines. It is described with the &%header%&
expansion item in section &<>& above.
-.vitem "&*${run{*&<&'command'&>&*&~*&<&'args'&>&*}{*&<&'string1'&>&*}&&&
+.vitem "&*${run <&'options'&> {*&<&'command&~arg&~list'&>&*}{*&<&'string1'&>&*}&&&
{*&<&'string2'&>&*}}*&"
.cindex "expansion" "running a command"
.cindex "&%run%& expansion item"
-The command and its arguments are first expanded as one string. The string is
-split apart into individual arguments by spaces, and then the command is run
+This item runs an external command, as a subprocess.
+.new
+One option is supported after the word &'run'&, comma-separated.
+
+If the option &'preexpand'& is not used,
+the command string is split into individual arguments by spaces
+and then each argument is expanded.
+Then the command is run
in a separate process, but under the same uid and gid. As in other command
executions from Exim, a shell is not used by default. If the command requires
a shell, you must explicitly code it.
+The command name may not be tainted, but the remaining arguments can be.
+
+&*Note*&: if tainted arguments are used, they are supplied by a
+potential attacker;
+a careful assessment for security vulnerabilities should be done.
+If the option &'preexpand'& is used,
+.wen
+the command and its arguments are first expanded as one string. The result is
+split apart into individual arguments by spaces, and then the command is run
+as above.
Since the arguments are split by spaces, when there is a variable expansion
which has an empty result, it will cause the situation that the argument will
simply be omitted when the program is actually executed by Exim. If the
@@ -10684,6 +10718,9 @@ in a string containing quotes, because it would interfere with the quotes
around the command arguments. A possible guard against this is to wrap the
variable in the &%sg%& operator to change any quote marks to some other
character.
+.new
+Neither the command nor any argument may be tainted.
+.wen
The standard input for the command exists, but is empty. The standard output
and standard error are set to the same file descriptor.
@@ -10796,23 +10833,21 @@ will sort an MX lookup into priority order.
-.new
.vitem &*${srs_encode&~{*&<&'secret'&>&*}{*&<&'return&~path'&>&*}{*&<&'original&~domain'&>&*}}*&
SRS encoding. See SECT &<>& for details.
-.wen
-.vitem &*${substr{*&<&'string1'&>&*}{*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&
+.vitem &*${substr{*&<&'start'&>&*}{*&<&'len'&>&*}{*&<&'subject'&>&*}}*&
.cindex "&%substr%& expansion item"
.cindex "substring extraction"
.cindex "expansion" "substring extraction"
The three strings are expanded; the first two must yield numbers. Call them
<&'n'&> and <&'m'&>. If you are using fixed values for these numbers, that is,
-if <&'string1'&> and <&'string2'&> do not change when they are expanded, you
+if <&'start'&> and <&'len'&> do not change when they are expanded, you
can use the simpler operator notation that avoids some of the braces:
.code
-${substr__:}
+${substr__:}
.endd
The second number is optional (in both notations).
If it is absent in the simpler format, the preceding underscore must also be
@@ -11219,10 +11254,8 @@ If the optional type is given it must be one of "a", "d", "h" or "l"
and selects address-, domain-, host- or localpart- lists to search among respectively.
Otherwise all types are searched in an undefined order and the first
matching list is returned.
-.new
&*Note*&: Neither string-expansion of lists referenced by named-list syntax elements,
nor expansion of lookup elements, is done by the &%listnamed%& operator.
-.wen
.vitem &*${local_part:*&<&'string'&>&*}*&
@@ -11234,7 +11267,8 @@ empty.
The parsing correctly handles SMTPUTF8 Unicode in the string.
-.vitem &*${mask:*&<&'IP&~address'&>&*/*&<&'bit&~count'&>&*}*&
+.vitem &*${mask:*&<&'IP&~address'&>&*/*&<&'bit&~count'&>&*}*& &&&
+ &*${mask_n:*&<&'IP&~address'&>&*/*&<&'bit&~count'&>&*}*&
.cindex "masked IP address"
.cindex "IP address" "masking"
.cindex "CIDR notation"
@@ -11248,8 +11282,14 @@ the result back to text, with mask appended. For example,
.code
${mask:10.111.131.206/28}
.endd
-returns the string &"10.111.131.192/28"&. Since this operation is expected to
-be mostly used for looking up masked addresses in files, the result for an IPv6
+returns the string &"10.111.131.192/28"&.
+
+Since this operation is expected to
+be mostly used for looking up masked addresses in files, the
+.new
+normal
+.wen
+result for an IPv6
address uses dots to separate components instead of colons, because colon
terminates a key string in lsearch files. So, for example,
.code
@@ -11259,6 +11299,10 @@ returns the string
.code
3ffe.ffff.836f.0a00.000a.0800.2000.0000/99
.endd
+.new
+If the optional form &*mask_n*& is used, IPv6 address result are instead
+returned in normailsed form, using colons and with zero-compression.
+.wen
Letters in IPv6 addresses are always output in lower case.
@@ -11590,14 +11634,14 @@ condition.
.cindex "expansion" "numeric comparison"
There are a number of symbolic operators for doing numeric comparisons. They
are:
-.display
-&`= `& equal
-&`== `& equal
-&`> `& greater
-&`>= `& greater or equal
-&`< `& less
-&`<= `& less or equal
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow "= " "equal"
+.irow "== " "equal"
+.irow "> " "greater"
+.irow ">= " "greater or equal"
+.irow "< " "less"
+.irow "<= " "less or equal"
+.endtable
For example:
.code
${if >{$message_size}{10M} ...
@@ -11785,11 +11829,9 @@ condition is true if the named file (or directory) exists. The existence test
is done by calling the &[stat()]& function. The use of the &%exists%& test in
users' filter files may be locked out by the system administrator.
-.new
&*Note:*& Testing a path using this condition is not a sufficient way of
de-tainting it.
Consider using a dsearch lookup.
-.wen
.vitem &*first_delivery*&
.cindex "delivery" "first"
@@ -11876,10 +11918,8 @@ case-independent.
Case and collation order are defined per the system C locale.
-.new
.vitem &*inbound_srs&~{*&<&'local&~part'&>&*}{*&<&'secret'&>&*}*&
SRS decode. See SECT &<>& for details.
-.wen
.vitem &*inlist&~{*&<&'string1'&>&*}{*&<&'string2'&>&*}*& &&&
@@ -11900,6 +11940,20 @@ ${if inlisti{Needle}{fOo:NeeDLE:bAr}}
${if forany{fOo:NeeDLE:bAr}{eqi{$item}{Needle}}}
.endd
+.new
+The variable &$value$& will be set for a successful match and can be
+used in the success clause of an &%if%& expansion item using the condition.
+.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using an inlist expansion condition"
+It will have the same taint status as the list; expansions such as
+.code
+${if inlist {$h_mycode:} {0 : 1 : 42} {$value}}
+.endd
+can be used for de-tainting.
+Any previous &$value$& is restored after the if.
+.wen
+
+
.vitem &*isip&~{*&<&'string'&>&*}*& &&&
&*isip4&~{*&<&'string'&>&*}*& &&&
&*isip6&~{*&<&'string'&>&*}*&
@@ -12096,6 +12150,19 @@ item can be used, as in all address lists, to cause subsequent items to
have their local parts matched casefully. Domains are always matched
caselessly.
+.new
+The variable &$value$& will be set for a successful match and can be
+used in the success clause of an &%if%& expansion item using the condition.
+.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using a match_local_part expansion condition"
+It will have the same taint status as the list; expansions such as
+.code
+${if match_local_part {$local_part} {alice : bill : charlotte : dave} {$value}}
+.endd
+can be used for de-tainting.
+Any previous &$value$& is restored after the if.
+.wen
+
Note that <&'string2'&> is not itself subject to string expansion, unless
Exim was built with the EXPAND_LISTMATCH_RHS option.
@@ -12112,8 +12179,9 @@ matched using &%match_ip%&.
.cindex "&%pam%& expansion condition"
&'Pluggable Authentication Modules'&
(&url(https://mirrors.edge.kernel.org/pub/linux/libs/pam/)) are a facility that is
-available in the latest releases of Solaris and in some GNU/Linux
-distributions. The Exim support, which is intended for use in conjunction with
+available in Solaris
+and in some GNU/Linux distributions.
+The Exim support, which is intended for use in conjunction with
the SMTP AUTH command, is available only if Exim is compiled with
.code
SUPPORT_PAM=yes
@@ -12290,6 +12358,16 @@ parsed but not evaluated.
This section contains an alphabetical list of all the expansion variables. Some
of them are available only when Exim is compiled with specific options such as
support for TLS or the content scanning extension.
+.new
+.cindex "tainted data"
+Variables marked as &'tainted'& are likely to carry data supplied by
+a potential attacker.
+Variables without such marking may also, depending on how their
+values are created.
+Such variables should not be further expanded,
+used as filenames
+or used as command-line arguments for external commands.
+.wen
.vlist
.vitem "&$0$&, &$1$&, etc"
@@ -12304,6 +12382,9 @@ variables may also be set externally by some other matching process which
precedes the expansion of the string. For example, the commands available in
Exim filter files include an &%if%& command with its own regular expression
matching condition.
+.new
+If the subject string was tainted then any captured substring will also be.
+.wen
.vitem "&$acl_arg1$&, &$acl_arg2$&, etc"
Within an acl condition, expansion condition or expansion item
@@ -12347,9 +12428,7 @@ warn !verify = sender
You can use &$acl_verify_message$& during the expansion of the &%message%& or
&%log_message%& modifiers, to include information about the verification
failure.
-.new
&*Note*&: The variable is cleared at the end of processing the ACL verb.
-.wen
.vitem &$address_data$&
.vindex "&$address_data$&"
@@ -12431,11 +12510,10 @@ authentication, which means this variable could also be visible in all of
the ACL's as well.
-.vitem &$authenticated_sender$&
+.tvar &$authenticated_sender$&
.cindex "sender" "authenticated"
.cindex "authentication" "sender"
.cindex "AUTH" "on MAIL command"
-.vindex "&$authenticated_sender$&"
When acting as a server, Exim takes note of the AUTH= parameter on an incoming
SMTP MAIL command if it believes the sender is sufficiently trusted, as
described in section &<>&. Unless the data is the string
@@ -12458,9 +12536,10 @@ command that does not succeed. Otherwise it is set to &"0"&. This makes it
possible to distinguish between &"did not try to authenticate"&
(&$sender_host_authenticated$& is empty and &$authentication_failed$& is set to
&"0"&) and &"tried to authenticate but failed"& (&$sender_host_authenticated$&
-is empty and &$authentication_failed$& is set to &"1"&). Failure includes any
-negative response to an AUTH command, including (for example) an attempt to use
-an undefined mechanism.
+is empty and &$authentication_failed$& is set to &"1"&).
+Failure includes cancellation of a authentication attempt,
+and any negative response to an AUTH command,
+(including, for example, an attempt to use an undefined mechanism).
.vitem &$av_failed$&
.cindex "content scanning" "AV scanner failure"
@@ -12587,8 +12666,7 @@ the following data from the lookup: the list's domain name, the key that was
looked up, the contents of any associated TXT record, and the value from the
main A record. See section &<>& for more details.
-.vitem &$domain$&
-.vindex "&$domain$&"
+.tvar &$domain$&
When an address is being routed, or delivered on its own, this variable
contains the domain. Uppercase letters in the domain are converted into lower
case for &$domain$&.
@@ -12653,14 +12731,12 @@ Often &$domain_data$& is usable in this role.
.vitem &$domain_data$&
.vindex "&$domain_data$&"
When the &%domains%& condition on a router
-.new
or an ACL
matches a domain
against a list, the match value is copied to &$domain_data$&.
This is an enhancement over previous versions of Exim, when it only
applied to the data read by a lookup.
For details on match values see section &<>& et. al.
-.wen
If the router routes the
address to a transport, the value is available in that transport. If the
@@ -12691,6 +12767,7 @@ There may be other characters following the minor version.
This value may be overridden by the &%exim_version%& main config option.
.vitem &$header_$&<&'name'&>
+.tmark
This is not strictly an expansion variable. It is expansion syntax for
inserting the message header line with the given name. Note that the name must
be terminated by colon or white space, because it may contain a wide variety of
@@ -12751,6 +12828,7 @@ allows you, for example, to do things like this:
deny hosts = net-lsearch;/some/file
message = $host_data
.endd
+
.vitem &$host_lookup_deferred$&
.cindex "host name" "lookup, failure of"
.vindex "&$host_lookup_deferred$&"
@@ -12833,8 +12911,7 @@ This variable contains the system load average, multiplied by 1000 so that it
is an integer. For example, if the load average is 0.21, the value of the
variable is 210. The value is recomputed every time the variable is referenced.
-.vitem &$local_part$&
-.vindex "&$local_part$&"
+.tvar &$local_part$&
When an address is being routed, or delivered on its own, this
variable contains the local part. When a number of addresses are being
delivered together (for example, multiple RCPT commands in an SMTP
@@ -12901,12 +12978,10 @@ to process local parts in a case-dependent manner in a router, you can set the
.vindex "&$local_part_data$&"
When the &%local_parts%& condition on a router or ACL
matches a local part list
-.new
the match value is copied to &$local_part_data$&.
This is an enhancement over previous versions of Exim, when it only
applied to the data read by a lookup.
For details on match values see section &<>& et. al.
-.wen
The &%check_local_user%& router option also sets this variable.
@@ -13011,11 +13086,10 @@ This variable is set at the start of a delivery attempt to contain the number
of seconds since the message was received. It does not change during a single
delivery attempt.
-.vitem &$message_body$&
+.tvar &$message_body$&
.cindex "body of message" "expansion variable"
.cindex "message body" "in expansion"
.cindex "binary zero" "in message body"
-.vindex "&$message_body$&"
.oindex "&%message_body_visible%&"
This variable contains the initial portion of a message's body while it is
being delivered, and is intended mainly for use in filter files. The maximum
@@ -13028,10 +13102,9 @@ easier to search for phrases that might be split over a line break. However,
this can be disabled by setting &%message_body_newlines%& to be true. Binary
zeros are always converted into spaces.
-.vitem &$message_body_end$&
+.tvar &$message_body_end$&
.cindex "body of message" "expansion variable"
.cindex "message body" "in expansion"
-.vindex "&$message_body_end$&"
This variable contains the final portion of a message's
body while it is being delivered. The format and maximum size are as for
&$message_body$&.
@@ -13058,15 +13131,13 @@ received. &*Note*&: This is &'not'& the contents of the &'Message-ID:'& header
line; it is the local id that Exim assigns to the message, for example:
&`1BXTIK-0001yO-VA`&.
-.vitem &$message_headers$&
-.vindex &$message_headers$&
+.tvar &$message_headers$&
This variable contains a concatenation of all the header lines when a message
is being processed, except for lines added by routers or transports. The header
lines are separated by newline characters. Their contents are decoded in the
same way as a header line that is inserted by &%bheader%&.
-.vitem &$message_headers_raw$&
-.vindex &$message_headers_raw$&
+.tvar &$message_headers_raw$&
This variable is like &$message_headers$& except that no processing of the
contents of header lines is done.
@@ -13143,9 +13214,8 @@ details, see section &<>&.
These variables are counters that can be incremented by means
of the &%add%& command in filter files.
-.vitem &$original_domain$&
+.tvar &$original_domain$&
.vindex "&$domain$&"
-.vindex "&$original_domain$&"
When a top-level address is being processed for delivery, this contains the
same value as &$domain$&. However, if a &"child"& address (for example,
generated by an alias, forward, or filter file) is being processed, this
@@ -13158,9 +13228,8 @@ If a new address is created by means of a &%deliver%& command in a system
filter, it is set up with an artificial &"parent"& address. This has the local
part &'system-filter'& and the default qualify domain.
-.vitem &$original_local_part$&
+.tvar &$original_local_part$&
.vindex "&$local_part$&"
-.vindex "&$original_local_part$&"
When a top-level address is being processed for delivery, this contains the
same value as &$local_part$&, unless a prefix or suffix was removed from the
local part, because &$original_local_part$& always contains the full local
@@ -13198,13 +13267,11 @@ messages received via the command line, this is the uid of the sending user.
For messages received by SMTP over TCP/IP, this is normally the uid of the Exim
user.
-.vitem &$parent_domain$&
-.vindex "&$parent_domain$&"
+.tvar &$parent_domain$&
This variable is similar to &$original_domain$& (see
above), except that it refers to the immediately preceding parent address.
-.vitem &$parent_local_part$&
-.vindex "&$parent_local_part$&"
+.tvar &$parent_local_part$&
This variable is similar to &$original_local_part$&
(see above), except that it refers to the immediately preceding parent address.
@@ -13223,6 +13290,11 @@ This is not an expansion variable, but is mentioned here because the string
(described under &%transport_filter%& in chapter &<>&).
It cannot be used in general expansion strings, and provokes an &"unknown
variable"& error if encountered.
+.new
+&*Note*&: This value permits data supplied by a potential attacker to
+be used in the command for a &(pipe)& transport.
+Such configurations should be carefully assessed for security vulnerbilities.
+.wen
.vitem &$primary_hostname$&
.vindex "&$primary_hostname$&"
@@ -13312,8 +13384,7 @@ including the one added by Exim (so its value is always greater than zero). It
is available in the DATA ACL, the non-SMTP ACL, and while routing and
delivering.
-.vitem &$received_for$&
-.vindex "&$received_for$&"
+.tvar &$received_for$&
If there is only a single recipient address in an incoming message, this
variable contains that address when the &'Received:'& header line is being
built. The value is copied after recipient rewriting has happened, but before
@@ -13405,8 +13476,7 @@ MAIL).
The main use of this variable is expected to be to distinguish between
rejections of MAIL and rejections of RCPT.
-.vitem &$recipients$&
-.vindex "&$recipients$&"
+.tvar &$recipients$&
This variable contains a list of envelope recipients for a message. A comma and
a space separate the addresses in the replacement text. However, the variable
is not generally available, to prevent exposure of Bcc recipients in
@@ -13443,10 +13513,12 @@ This variable is set to contain the matching regular expression after a
When a &%regex%& or &%mime_regex%& ACL condition succeeds,
these variables contain the
captured substrings identified by the regular expression.
+.new
+If the subject string was tainted then so will any captured substring.
+.wen
-.vitem &$reply_address$&
-.vindex "&$reply_address$&"
+.tvar &$reply_address$&
When a message is being processed, this variable contains the contents of the
&'Reply-To:'& header line if one exists and it is not empty, or otherwise the
contents of the &'From:'& header line. Apart from the removal of leading
@@ -13495,8 +13567,7 @@ One of its values causes the address to be passed to another router. When this
happens, &$self_hostname$& is set to the name of the local host that the
original router encountered. In other circumstances its contents are null.
-.vitem &$sender_address$&
-.vindex "&$sender_address$&"
+.tvar &$sender_address$&
When a message is being processed, this variable contains the sender's address
that was received in the message's envelope. The case of letters in the address
is retained, in both the local part and the domain. For bounce messages, the
@@ -13511,12 +13582,10 @@ distinguish it from data from a recipient address. The value does not persist
after the end of the current ACL statement. If you want to preserve it for
longer, you can save it in an ACL variable.
-.vitem &$sender_address_domain$&
-.vindex "&$sender_address_domain$&"
+.tvar &$sender_address_domain$&
The domain portion of &$sender_address$&.
-.vitem &$sender_address_local_part$&
-.vindex "&$sender_address_local_part$&"
+.tvar &$sender_address_local_part$&
The local part portion of &$sender_address$&.
.vitem &$sender_data$&
@@ -13554,8 +13623,7 @@ This boolean variable is true if a successful HELO verification was
.cindex "DNS" "DNSSEC"
done using DNS information the resolver library stated was authenticated data.
-.vitem &$sender_helo_name$&
-.vindex "&$sender_helo_name$&"
+.tvar &$sender_helo_name$&
When a message is received from a remote host that has issued a HELO or EHLO
command, the argument of that command is placed in this variable. It is also
set if HELO or EHLO is used when a message is received using SMTP locally via
@@ -13612,8 +13680,7 @@ all EDNS0 options, then this will have no effect. OpenBSD's asr resolver
is known to currently ignore EDNS0, documented in CAVEATS of asr_run(3).
-.vitem &$sender_host_name$&
-.vindex "&$sender_host_name$&"
+.tvar &$sender_host_name$&
When a message is received from a remote host, this variable contains the
host's name as obtained by looking up its IP address. For messages received by
other means, this variable is empty.
@@ -13731,8 +13798,7 @@ host name, as specified by the &%smtp_active_hostname%& option. The value of
&$smtp_active_hostname$& is saved with any message that is received, so its
value can be consulted during routing and delivery.
-.vitem &$smtp_command$&
-.vindex "&$smtp_command$&"
+.tvar &$smtp_command$&
During the processing of an incoming SMTP command, this variable contains the
entire command. This makes it possible to distinguish between HELO and EHLO in
the HELO ACL, and also to distinguish between commands such as these:
@@ -13745,9 +13811,8 @@ command, the address in &$smtp_command$& is the original address before any
rewriting, whereas the values in &$local_part$& and &$domain$& are taken from
the address after SMTP-time rewriting.
-.vitem &$smtp_command_argument$&
+.tvar &$smtp_command_argument$&
.cindex "SMTP" "command, argument for"
-.vindex "&$smtp_command_argument$&"
While an ACL is running to check an SMTP command, this variable contains the
argument, that is, the text that follows the command name, with leading white
space removed. Following the introduction of &$smtp_command$&, this variable is
@@ -13980,18 +14045,15 @@ If certificate verification fails it may refer to a failing chain element
which is not the leaf.
-.new
.vitem &$tls_in_resumption$& &&&
&$tls_out_resumption$&
.vindex &$tls_in_resumption$&
.vindex &$tls_out_resumption$&
.cindex TLS resumption
Observability for TLS session resumption. See &<>& for details.
-.wen
-.vitem &$tls_in_sni$&
-.vindex "&$tls_in_sni$&"
+.tvar &$tls_in_sni$&
.vindex "&$tls_sni$&"
.cindex "TLS" "Server Name Indication"
.cindex "TLS" SNI
@@ -14173,9 +14235,7 @@ taint mode of the Perl interpreter. You are encouraged to set this
option to a true value. To avoid breaking existing installations, it
defaults to false.
-.new
&*Note*&: This is entirely separate from Exim's tainted-data tracking.
-.wen
.section "Calling Perl subroutines" "SECID86"
@@ -14612,7 +14672,6 @@ listed in more than one group.
.section "Miscellaneous" "SECID96"
.table2
.row &%add_environment%& "environment variables"
-.row &%allow_insecure_tainted_data%& "turn taint errors into warnings"
.row &%bi_command%& "to run for &%-bi%& command line option"
.row &%debug_store%& "do extra internal checks"
.row &%disable_ipv6%& "do no IPv6 processing"
@@ -15226,19 +15285,6 @@ domains (defined in the named domain list &%local_domains%& in the default
configuration). This &"magic string"& matches the domain literal form of all
the local host's IP addresses.
-.new
-.option allow_insecure_tainted_data main boolean false
-.cindex "de-tainting"
-.oindex "allow_insecure_tainted_data"
-The handling of tainted data may break older (pre 4.94) configurations.
-Setting this option to "true" turns taint errors (which result in a temporary
-message rejection) into warnings. This option is meant as mitigation only
-and deprecated already today. Future releases of Exim may ignore it.
-The &%taint%& log selector can be used to suppress even the warnings.
-.wen
-
-
-
.option allow_mx_to_ip main boolean false
.cindex "MX record" "pointing to IP address"
It appears that more and more DNS zone administrators are breaking the rules
@@ -15899,8 +15945,8 @@ described in section &<>&.
.cindex "ESMTP extensions" DSN
DSN extensions (RFC3461) will be advertised in the EHLO message to,
and accepted from, these hosts.
-Hosts may use the NOTIFY and ENVID options on RCPT TO commands,
-and RET and ORCPT options on MAIL FROM commands.
+Hosts may use the NOTIFY and ORCPT options on RCPT TO commands,
+and RET and ENVID options on MAIL FROM commands.
A NOTIFY=SUCCESS option requests success-DSN messages.
A NOTIFY= option with no argument requests that no delay or failure DSNs
are sent.
@@ -16342,7 +16388,6 @@ hosts_connection_nolog = :
If the &%smtp_connection%& log selector is not set, this option has no effect.
-.new
.option hosts_require_alpn main "host list&!!" unset
.cindex ALPN "require negotiation in server"
.cindex TLS ALPN
@@ -16354,7 +16399,6 @@ See also the &%tls_alpn%& option.
&*Note*&: prevention of fallback to in-clear connection is not
managed by this option, and should be done separately.
-.wen
.option hosts_proxy main "host list&!!" unset
@@ -16893,14 +16937,11 @@ The option is expanded before use.
If the platform supports Linux-style abstract socket names, the result
is used with a nul byte prefixed.
Otherwise,
-.new "if nonempty,"
it should be a full path name and use a directory accessible
to Exim.
-.new
If this option is set as empty,
or the command line &%-oY%& option is used, or
-.wen
the command line uses a &%-oX%& option and does not use &%-oP%&,
then a notifier socket is not created.
@@ -17098,9 +17139,7 @@ When used, the pipelining saves on roundtrip times.
See also the &%hosts_pipe_connect%& smtp transport option.
-.new
The SMTP service extension keyword advertised is &"PIPE_CONNECT"&.
-.wen
.option prdr_enable main boolean false
@@ -17181,12 +17220,10 @@ admin user unless &%prod_requires_admin%& is set false. See also
&%queue_list_requires_admin%& and &%commandline_checks_require_admin%&.
-.new
.option proxy_protocol_timeout main time 3s
.cindex proxy "proxy protocol"
This option sets the timeout for proxy protocol negotiation.
For details see section &<>&.
-.wen
.option qualify_domain main string "see below"
@@ -17224,7 +17261,6 @@ domains that do not match are processed. All other deliveries wait until the
next queue run. See also &%hold_domains%& and &%queue_smtp_domains%&.
-.new
.option queue_fast_ramp main boolean false
.cindex "queue runner" "two phase"
.cindex "queue" "double scanning"
@@ -17232,7 +17268,6 @@ If set to true, two-phase queue runs, initiated using &%-qq%& on the
command line, may start parallel delivery processes during their first
phase. This will be done when a threshold number of messages have been
routed for a single host.
-.wen
.option queue_list_requires_admin main boolean true
@@ -17672,11 +17707,9 @@ results in the transfer of a message. After the limit is reached, a 421
response is given to subsequent MAIL commands. This limit is a safety
precaution against a client that goes mad (incidents of this type have been
seen).
-.new
The option is expanded after the HELO or EHLO is received
and may depend on values available at that time.
An empty or zero value after expansion removes the limit.
-.wen
.option smtp_accept_max_per_host main string&!! unset
@@ -18382,7 +18415,6 @@ using the &%tls_certificate%& option. If TLS support for incoming connections
is not required the &%tls_advertise_hosts%& option should be set empty.
-.new
.option tls_alpn main "string list&!!" "smtp : esmtp"
.cindex TLS "Application Layer Protocol Names"
.cindex TLS ALPN
@@ -18392,7 +18424,6 @@ the TLS library supports ALPN,
and the client offers either more than
ALPN name or a name which does not match the list,
the TLS connection is declined.
-.wen
.option tls_certificate main "string list&!!" unset
@@ -18425,11 +18456,9 @@ Server Name Indication extension, then this option and others documented in
&<>& will be re-expanded.
If this option is unset or empty a self-signed certificate will be
-.new
used.
Under Linux this is generated at daemon startup; on other platforms it will be
generated fresh for every connection.
-.wen
.option tls_crl main string&!! unset
.cindex "TLS" "server certificate revocation list"
@@ -18472,12 +18501,7 @@ larger prime than requested.
The value of this option is expanded and indicates the source of DH parameters
to be used by Exim.
-This option is ignored for GnuTLS version 3.6.0 and later.
-The library manages parameter negotiation internally.
-
-&*Note: The Exim Maintainers strongly recommend,
-for other TLS library versions,
-using a filename with site-generated
+&*Note: The Exim Maintainers strongly recommend using a filename with site-generated
local DH parameters*&, which has been supported across all versions of Exim. The
other specific constants available are a fallback so that even when
"unconfigured", Exim can offer Perfect Forward Secrecy in older ciphersuites in TLS.
@@ -18528,8 +18552,17 @@ of the later IKE values, which led into RFC7919 providing new fixed constants
(the "ffdhe" identifiers).
At this point, all of the "ike" values should be considered obsolete;
-they're still in Exim to avoid breaking unusual configurations, but are
+they are still in Exim to avoid breaking unusual configurations, but are
candidates for removal the next time we have backwards-incompatible changes.
+.new
+Two of them in particular (&`ike1`& and &`ike22`&) are called out by RFC 8247
+as MUST NOT use for IPSEC, and two more (&`ike23`& and &`ike24`&) as
+SHOULD NOT.
+Because of this, Exim regards them as deprecated; if either of the first pair
+are used, warnings will be logged in the paniclog, and if any are used then
+warnings will be logged in the mainlog.
+All four will be removed in a future Exim release.
+.wen
The TLS protocol does not negotiate an acceptable size for this; clients tend
to hard-drop connections if what is offered by the server is unacceptable,
@@ -18640,12 +18673,10 @@ preference order of the available ciphers. Details are given in sections
&<>& and &<>&.
-.new
.option tls_resumption_hosts main "host list&!!" unset
.cindex TLS resumption
This option controls which connections to offer the TLS resumption feature.
See &<>& for details.
-.wen
.option tls_try_verify_hosts main "host list&!!" unset
@@ -18704,7 +18735,8 @@ either &%tls_verify_hosts%& or &%tls_try_verify_hosts%& is set and
Any client that matches &%tls_verify_hosts%& is constrained by
&%tls_verify_certificates%&. When the client initiates a TLS session, it must
present one of the listed certificates. If it does not, the connection is
-aborted. &*Warning*&: Including a host in &%tls_verify_hosts%& does not require
+aborted.
+&*Warning*&: Including a host in &%tls_verify_hosts%& does not require
the host to use TLS. It can still send SMTP commands through unencrypted
connections. Forcing a client to use TLS has to be done separately using an
ACL to reject inappropriate commands when the connection is not encrypted.
@@ -18877,11 +18909,9 @@ which the preconditions are tested. The order of expansion of the options that
provide data for a transport is: &%errors_to%&, &%headers_add%&,
&%headers_remove%&, &%transport%&.
-.new
The name of a router is limited to be &drivernamemax; ASCII characters long;
prior to Exim 4.95 names would be silently truncated at this length, but now
it is enforced.
-.wen
.option address_data routers string&!! unset
@@ -19010,6 +19040,7 @@ than trying to read &_/etc/passwd_& directly. This means that other methods of
holding password data (such as NIS) are supported. If the local part is a local
user,
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using router check_local_user option"
&$local_part_data$& is set to an untainted version of the local part and
&$home$& is set from the password data. The latter can be tested in other
preconditions that are evaluated after this one (the order of evaluation is
@@ -19873,10 +19904,8 @@ Values containing a list-separator should have them doubled.
When a router runs, the strings are evaluated in order,
to create variables which are added to the set associated with
the address.
-.new
This is done immediately after all the preconditions, before the
evaluation of the &%address_data%& option.
-.wen
The variable is set with the expansion of the value.
The variables can be used by the router options
(not including any preconditions)
@@ -22425,11 +22454,9 @@ and &$original_domain$& is never set.
.scindex IIDgenoptra1 "generic options" "transport"
.scindex IIDgenoptra2 "options" "generic; for transports"
.scindex IIDgenoptra3 "transport" "generic options for"
-.new
The name of a transport is limited to be &drivernamemax; ASCII characters long;
prior to Exim 4.95 names would be silently truncated at this length, but now
it is enforced.
-.wen
The following generic options apply to all transports:
@@ -22500,13 +22527,11 @@ header, Exim has a configuration option (&%envelope_to_remove%&) which requests
its removal from incoming messages, so that delivered messages can safely be
resent to other recipients.
-.new
&*Note:*& If used on a transport handling multiple recipients
(the smtp transport unless &%rcpt_max%& is 1, the appendfile, pipe or lmtp
transport if &%batch_max%& is greater than 1)
then information about Bcc recipients will be leaked.
Doing so is generally not advised.
-.wen
.option event_action transports string&!! unset
@@ -22849,9 +22874,10 @@ an ideal name for this feature here, but as it was already implemented for the
The expansion variables &$host$& and &$host_address$& are available when the
transport is a remote one. They contain the name and IP address of the host to
which the message is being sent. For example:
+. used to have $sender_address in this cmdline, but it's tainted
.code
transport_filter = /some/directory/transport-filter.pl \
- $host $host_address $sender_address $pipe_addresses
+ $host $host_address $pipe_addresses
.endd
Two problems arise if you want to use more complicated expansion items to
@@ -23266,10 +23292,8 @@ directories defined by the &%directory%& option. In the case of maildir
delivery, it applies to the top level directory, not the maildir directories
beneath.
-.new
The option must be set to one of the words &"anywhere"&, &"inhome"&, or
&"belowhome"&, or to an absolute path.
-.wen
In the second and third cases, a home directory must have been
set for the transport, and the file or directory being created must
@@ -23282,7 +23306,6 @@ are generated from users' &_.forward_& files. These are usually handled
by an &(appendfile)& transport called &%address_file%&. See also
&%file_must_exist%&.
-.new
In the fourth case,
the value given for this option must be an absolute path for an
existing directory.
@@ -23290,9 +23313,9 @@ The value is used for checking instead of a home directory;
checking is done in "belowhome" mode.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using appendfile create_file option"
If "belowhome" checking is used, the file or directory path
becomes de-tainted.
-.wen
.option directory appendfile string&!! unset
@@ -23306,10 +23329,8 @@ appended to a single mailbox file. A number of different formats are provided
(see &%maildir_format%& and &%mailstore_format%&), and see section
&<>& for further details of this form of delivery.
-.new
The result of expansion must not be tainted, unless the &%create_file%& option
specifies a path.
-.wen
.option directory_file appendfile string&!! "see below"
@@ -23343,10 +23364,8 @@ specifies a single file, to which the message is appended. One or more of
&%use_fcntl_lock%&, &%use_flock_lock%&, or &%use_lockfile%& must be set with
&%file%&.
-.new
The result of expansion must not be tainted, unless the &%create_file%& option
specifies a path.
-.wen
.cindex "NFS" "lock file"
.cindex "locking files"
@@ -24730,6 +24749,11 @@ This list is a compromise for maximum compatibility with other MTAs. Note that
the &%environment%& option can be used to add additional variables to this
environment. The environment for the &(pipe)& transport is not subject
to the &%add_environment%& and &%keep_environment%& main config options.
+.new
+&*Note*&: Using enviroment variables loses track of tainted data.
+Writers of &(pipe)& transport commands should be wary of data supplied
+by potential attackers.
+.wen
.display
&`DOMAIN `& the domain of the address
&`HOME `& the home directory, if set
@@ -24821,6 +24845,11 @@ the &%path%& option below). The command is split up into separate arguments by
Exim, and each argument is separately expanded, as described in section
&<>& above.
+.new
+.cindex "tainted data"
+No part of the resulting command may be tainted.
+.wen
+
.option environment pipe string&!! unset
.cindex "&(pipe)& transport" "environment for command"
@@ -25136,12 +25165,15 @@ use a shell to run pipe commands.
.cindex "Cyrus"
The next example shows a transport and a router for a system where local
deliveries are handled by the Cyrus IMAP server.
+. Used to have R: local_part_suffix = .* + T: -m $local_part_suffix_v
+. but that suffix is tainted so cannot be used in a command arg
+. Really, you'd want to use a lookup for acceptable suffixes to do real detainting
.code
# transport
local_delivery_cyrus:
driver = pipe
command = /usr/cyrus/bin/deliver \
- -m ${substr_1:$local_part_suffix} -- $local_part
+ -- $local_part_data
user = cyrus
group = mail
return_output
@@ -25153,7 +25185,6 @@ local_delivery_cyrus:
local_user_cyrus:
driver = accept
check_local_user
- local_part_suffix = .*
transport = local_delivery_cyrus
.endd
Note the unsetting of &%message_prefix%& and &%message_suffix%&, and the use of
@@ -25519,12 +25550,45 @@ servers or different local IP addresses. For example, if you want the string
that is used for &%helo_data%& to be obtained by a DNS lookup of the outgoing
interface address, you could use this:
.code
-helo_data = ${lookup dnsdb{ptr=$sending_ip_address}{$value}\
+helo_data = ${lookup dnsdb{ptr=$sending_ip_address} \
+ {${listextract{1}{<\n $value}}} \
{$primary_hostname}}
.endd
The use of &%helo_data%& applies both to sending messages and when doing
callouts.
+.new
+.option host_name_extract smtp "string list&!!" "see below"
+.cindex "load balancer" "hosts behind"
+.cindex TLS resumption
+Some mail-accepting sites
+(notably Microsoft)
+operate many servers behind a network load-balancer. When this is done,
+with separated TLS session caches, TLS session resuption becomes problematic.
+It will only succeed when the same server happens to be selected by the
+load-balancer, matching the session stored in the client's cache.
+
+Exim can pull out a server name, if there is one, from the response to the
+client's SMTP EHLO command.
+The default value of this option:
+.code
+ ${if and { {match {$host} {.outlook.com\$}} \
+ {match {$item} {\N^250-([\w.]+)\s\N}} \
+ } {$1}}
+.endd
+suffices for one known case.
+During the expansion of this option the &$item$& variable will have the
+server's EHLO response.
+The result of the option expansion is included in the key used to store and
+retrieve the TLS session, for session resumption.
+
+Operators of high-load sites may wish to evaluate their logs for indications
+of other destination sites operating load-balancers, and develop a suitable
+expression for this option.
+The smtp:ehlo event and the &$tls_out_resumption$& variable
+will be useful for such work.
+.wen
+
.option hosts smtp "string list&!!" unset
Hosts are associated with an address by a router such as &(dnslookup)&, which
finds the hosts by looking up the address domain in the DNS, or by
@@ -25592,7 +25656,10 @@ so combines well with TCP Fast Open.
See also the &%pipelining_connect_advertise_hosts%& main option.
Note:
-When the facility is used, the transport &%helo_data%& option
+.new
+When the facility is used, if the transport &%interface%& option is unset
+the &%helo_data%& option
+.wen
will be expanded before the &$sending_ip_address$& variable
is filled in.
A check is made for the use of that variable, without the
@@ -25703,7 +25770,6 @@ Exim will request a Certificate Status on a
TLS session for any host that matches this list.
&%tls_verify_certificates%& should also be set for the transport.
-.new
.option hosts_require_alpn smtp "host list&!!" unset
.cindex ALPN "require negotiation in client"
.cindex TLS ALPN
@@ -25715,7 +25781,6 @@ See also the &%tls_alpn%& option.
&*Note*&: prevention of fallback to in-clear connection is not
managed by this option; see &%hosts_require_tls%&.
-.wen
.option hosts_require_dane smtp "host list&!!" unset
.cindex DANE "transport options"
@@ -25750,9 +25815,7 @@ incoming messages, use an appropriate ACL.
This option provides a list of servers to which, provided they announce
authentication support, Exim will attempt to authenticate as a client when it
connects. If authentication fails
-.new
and &%hosts_require_auth%& permits,
-.wen
Exim will try to transfer the message unauthenticated.
See also chapter &<>& for details of authentication.
@@ -25768,13 +25831,11 @@ BDAT will not be used in conjunction with a transport filter.
.option hosts_try_dane smtp "host list&!!" *
.cindex DANE "transport options"
.cindex DANE "attempting for certain servers"
-.new
If built with DANE support, Exim will look up a
TLSA record for any host matching the list,
If one is found and that lookup was DNSSEC-validated,
then Exim requires that a DANE-verified TLS connection is made for that host;
there will be no fallback to in-clear communication.
-.wen
See the &%dnssec_request_domains%& router and transport options.
See section &<>&.
@@ -25863,7 +25924,6 @@ so can cause parallel connections to the same host if &%remote_max_parallel%&
permits this. A value setting of zero disables the limit.
-.new
.option message_linelength_limit smtp integer 998
.cindex "line length" limit
This option sets the maximum line length, in bytes, that the transport
@@ -25874,7 +25934,6 @@ The default value is that defined by the SMTP standards.
It is generally wise to also check in the data ACL so that messages
received via SMTP can be refused without producing a bounce.
-.wen
.option multi_domain smtp boolean&!! true
@@ -25890,11 +25949,9 @@ It is expanded per-address and can depend on any of
&$address_data$&, &$domain_data$&, &$local_part_data$&,
&$host$&, &$host_address$& and &$host_port$&.
-.new
If the connection is DANE-enabled then this option is ignored;
only messages having the domain used for the DANE TLSA lookup are
sent on the connection.
-.wen
.option port smtp string&!! "see below"
.cindex "port" "sending TCP/IP"
@@ -26000,7 +26057,6 @@ This option enables use of SOCKS proxies for connections made by the
transport. For details see section &<>&.
-.new
.option tls_alpn smtp string&!! unset
.cindex TLS "Application Layer Protocol Names"
.cindex TLS ALPN
@@ -26011,7 +26067,6 @@ the value given is used.
As of writing no value has been standardised for email use.
The authors suggest using &"smtp"&.
-.wen
@@ -26079,12 +26134,10 @@ is used in different ways by OpenSSL and GnuTLS (see sections
ciphers is a preference order.
-.new
.option tls_resumption_hosts smtp "host list&!!" unset
.cindex TLS resumption
This option controls which connections to use the TLS resumption feature.
See &<>& for details.
-.wen
@@ -26094,9 +26147,7 @@ See &<>& for details.
.cindex SNI "setting in client"
.vindex "&$tls_sni$&"
If this option is set
-.new
and the connection is not DANE-validated
-.wen
then it sets the $tls_out_sni variable and causes any
TLS session to pass this value as the Server Name Indication extension to
the remote side, which can be used by the remote side to select an appropriate
@@ -26191,6 +26242,10 @@ certificate verification must succeed.
The &%tls_verify_certificates%& option must also be set.
If both this option and &%tls_try_verify_hosts%& are unset
operation is as if this option selected all hosts.
+&*Warning*&: Including a host in &%tls_verify_hosts%& does not require
+that connections use TLS.
+Fallback to in-clear communication will be done unless restricted by
+the &%hosts_require_tls%& option.
.option utf8_downconvert smtp integer&!! -1
.cindex utf8 "address downconversion"
@@ -27309,11 +27364,9 @@ permitted to use it as a relay. SMTP authentication is not of relevance to the
transfer of mail between servers that have no managerial connection with each
other.
-.new
The name of an authenticator is limited to be &drivernamemax; ASCII characters long;
prior to Exim 4.95 names would be silently truncated at this length, but now
it is enforced.
-.wen
.cindex "AUTH" "description of"
.cindex "ESMTP extensions" AUTH
@@ -28058,10 +28111,8 @@ fixed_plain:
.endd
The lack of colons means that the entire text is sent with the AUTH
command, with the circumflex characters converted to NULs.
-.new
Note that due to the ambiguity of parsing three consectutive circumflex characters
there is no way to provide a password having a leading circumflex.
-.wen
A similar example
@@ -28388,11 +28439,9 @@ realease for the SCRAM-SHA-256 method.
The macro _HAVE_AUTH_GSASL_SCRAM_SHA_256 will be defined
when this happens.
-.new
To see the list of mechanisms supported by the library run Exim with "auth" debug
enabled and look for a line containing "GNU SASL supports".
Note however that some may not have been tested from Exim.
-.wen
.option client_authz gsasl string&!! unset
@@ -28415,10 +28464,8 @@ the account name to be used.
.option client_spassword gsasl string&!! unset
-.new
This option is only supported for library versions 1.9.1 and greater.
The macro _HAVE_AUTH_GSASL_SCRAM_S_KEY will be defined when this is so.
-.wen
If a SCRAM mechanism is being used and this option is set
and correctly sized
@@ -28430,7 +28477,6 @@ with the PBKDF2-prepared password, hex-encoded.
Note that this value will depend on the salt and iteration-count
supplied by the server.
The option is expanded before use.
-.new
During the expansion &$auth1$& is set with the client username,
&$auth2$& with the iteration count, and
&$auth3$& with the salt.
@@ -28447,7 +28493,6 @@ If the authentication succeeds then the above variables are set,
plus the calculated salted password value value in &$auth4$&,
during the expansion of the &%client_set_id%& option.
A side-effect of this expansion can be used to prime the cache.
-.wen
.option server_channelbinding gsasl boolean false
@@ -28474,12 +28519,10 @@ of Exim might have switched the default to be true.
. Do not plan to rely upon this feature for security, ever, without consulting
. with a subject matter expert (a cryptographic engineer).
-.new
This option was deprecated in previous releases due to doubts over
the "Triple Handshake" vulnerability.
Exim takes suitable precausions (requiring Extended Master Secret if TLS
Session Resumption was used) for safety.
-.wen
.option server_hostname gsasl string&!! "see below"
@@ -29152,12 +29195,10 @@ Some other recently added features may only be available in one or the other.
This should be documented with the feature. If the documentation does not
explicitly state that the feature is infeasible in the other TLS
implementation, then patches are welcome.
-.new
.next
The output from "exim -bV" will show which (if any) support was included
in the build.
Also, the macro "_HAVE_OPENSSL" or "_HAVE_GNUTLS" will be defined.
-.wen
.endlist
@@ -29631,7 +29672,6 @@ There is no current way to staple a proof for a client certificate.
.endd
-.new
.section "Caching of static server configuration items" "SECTserverTLScache"
.cindex certificate caching
.cindex privatekey caching
@@ -29683,7 +29723,6 @@ is acceptable in configurations for the Exim executavble.
Caching of the system Certificate Authorities bundle can
save siginificant time and processing on every TLS connection
accepted by Exim.
-.wen
@@ -29755,13 +29794,11 @@ or need not succeed respectively.
The &%tls_verify_cert_hostnames%& option lists hosts for which additional
name checks are made on the server certificate.
-.new
The match against this list is, as per other Exim usage, the
IP for the host. That is most closely associated with the
name on the DNS A (or AAAA) record for the host.
However, the name that needs to be in the certificate
is the one at the head of any CNAME chain leading to the A record.
-.wen
The option defaults to always checking.
The &(smtp)& transport has two OCSP-related options:
@@ -29809,7 +29846,6 @@ outgoing connection.
-.new
.section "Caching of static client configuration items" "SECTclientTLScache"
.cindex certificate caching
.cindex privatekey caching
@@ -29860,7 +29896,6 @@ is acceptable in configurations for the Exim executavble.
Caching of the system Certificate Authorities bundle can
save siginificant time and processing on every TLS connection
initiated by Exim.
-.wen
@@ -29902,7 +29937,7 @@ for the lifetime of the client connection (including during authentication).
.new
If DANE validated the connection attempt then the value of the &%tls_sni%& option
-is forced to the domain part of the recipient address.
+is forced to the name of the destination host, after any MX- or CNAME-following.
.wen
Except during SMTP client sessions, if &$tls_in_sni$& is set then it is a string
@@ -29945,7 +29980,6 @@ When Exim is built against GnuTLS, SNI support is available as of GnuTLS
0.5.10. (Its presence predates the current API which Exim uses, so if Exim
built, then you have SNI support).
-.new
.cindex TLS ALPN
.cindex ALPN "general information"
.cindex TLS "Application Layer Protocol Names"
@@ -29972,7 +30006,6 @@ depends on the behavious of the peer
This feature is available when Exim is built with
OpenSSL 1.1.0 or later or GnuTLS 3.2.0 or later;
the macro _HAVE_TLS_ALPN will be defined when this is so.
-.wen
@@ -30120,7 +30153,6 @@ Open-source PKI book, available online at
.ecindex IIDencsmtp2
-.new
.section "TLS Resumption" "SECTresumption"
.cindex TLS resumption
TLS Session Resumption for TLS 1.2 and TLS 1.3 connections can be used (defined
@@ -30212,7 +30244,6 @@ Issues:
.endlist
.endlist
-.wen
.section DANE "SECDANE"
@@ -30562,6 +30593,11 @@ accepted by an &%accept%& verb that has a &%message%& modifier, the contents of
the message override the banner message that is otherwise specified by the
&%smtp_banner%& option.
+.new
+For tls-on-connect connections, the ACL is run after the TLS connection
+is accepted (however, &%host_reject_connection%& is tested before).
+.wen
+
.section "The EHLO/HELO ACL" "SECID192"
.cindex "EHLO" "ACL for"
@@ -31490,11 +31526,9 @@ anyway. If the message contains newlines, this gives rise to a multi-line SMTP
response.
.vindex "&$acl_verify_message$&"
-.new
While the text is being expanded, the &$acl_verify_message$& variable
contains any message previously set.
Afterwards, &$acl_verify_message$& is cleared.
-.wen
If &%message%& is used on a statement that verifies an address, the message
specified overrides any message that is generated by the verification process.
@@ -31681,12 +31715,43 @@ sender when the destination system is doing content-scan based rejection.
This control turns on debug logging, almost as though Exim had been invoked
with &`-d`&, with the output going to a new logfile in the usual logs directory,
by default called &'debuglog'&.
-The filename can be adjusted with the &'tag'& option, which
-may access any variables already defined. The logging may be adjusted with
-the &'opts'& option, which takes the same values as the &`-d`& command-line
-option.
-Logging started this way may be stopped, and the file removed,
-with the &'kill'& option.
+
+.new
+Options are a slash-separated list.
+If an option takes an argument, the option name and argument are separated by
+an equals character.
+Several options are supported:
+.wen
+.display
+tag=<&'suffix'&> The filename can be adjusted with thise option.
+ The argument, which may access any variables already defined,
+ is appended to the default name.
+
+opts=<&'debug&~options'&> The argument specififes what is to be logged,
+ using the same values as the &`-d`& command-line option.
+
+stop Logging started with this control may be
+ stopped by using this option.
+
+kill Logging started with this control may be
+ stopped by using this option.
+ Additionally the debug file will be removed,
+ providing one means for speculative debug tracing.
+
+pretrigger=<&'size'&> This option specifies a memory buffuer to be used
+ for pre-trigger debug capture.
+ Debug lines are recorded in the buffer until
+ and if) a trigger occurs; at which time they are
+ dumped to the debug file. Newer lines displace the
+ oldest if the buffer is full. After a trigger,
+ immediate writes to file are done as normal.
+
+trigger=<&'reason'&> This option selects cause for the pretrigger buffer
+ see above) to be copied to file. A reason of $*now*
+ take effect immediately; one of &*paniclog*& triggers
+ on a write to the panic log.
+.endd
+
Some examples (which depend on variables that don't exist in all
contexts):
.code
@@ -31695,6 +31760,8 @@ contexts):
control = debug/opts=+expand+acl
control = debug/tag=.$message_exim_id/opts=+expand
control = debug/kill
+ control = debug/opts=+all/pretrigger=1024/trigger=paniclog
+ control = debug/trigger=now
.endd
@@ -32325,6 +32392,14 @@ content-scanning extension, and is available only in the DATA, MIME, and
non-SMTP ACLs. It causes the incoming message to be scanned for a match with
any of the regular expressions. For details, see chapter &<>&.
+.new
+.vitem &*seen&~=&~*&<&'parameters'&>
+.cindex "&%sseen%& ACL condition"
+This condition can be used to test if a situation has been previously met,
+for example for greylisting.
+Details are given in section &<>&.
+.wen
+
.vitem &*sender_domains&~=&~*&<&'domain&~list'&>
.cindex "&%sender_domains%& ACL condition"
.cindex "sender" "ACL checking"
@@ -32583,11 +32658,11 @@ This is usually the required action when &%dnslists%& is used with &%deny%&
(which is the most common usage), because it prevents a DNS failure from
blocking mail. However, you can change this behaviour by putting one of the
following special items in the list:
-.display
-&`+include_unknown `& behave as if the item is on the list
-&`+exclude_unknown `& behave as if the item is not on the list (default)
-&`+defer_unknown `& give a temporary error
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow "+include_unknown" "behave as if the item is on the list"
+.irow "+exclude_unknown" "behave as if the item is not on the list (default)"
+.irow "+defer_unknown " "give a temporary error"
+.endtable
.cindex "&`+include_unknown`&"
.cindex "&`+exclude_unknown`&"
.cindex "&`+defer_unknown`&"
@@ -32736,25 +32811,23 @@ DNS lists are constructed using address records in the DNS. The original RBL
just used the address 127.0.0.1 on the right hand side of each record, but the
RBL+ list and some other lists use a number of values with different meanings.
The values used on the RBL+ list are:
-.display
-127.1.0.1 RBL
-127.1.0.2 DUL
-127.1.0.3 DUL and RBL
-127.1.0.4 RSS
-127.1.0.5 RSS and RBL
-127.1.0.6 RSS and DUL
-127.1.0.7 RSS and DUL and RBL
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow 127.1.0.1 "RBL"
+.irow 127.1.0.2 "DUL"
+.irow 127.1.0.3 "DUL and RBL"
+.irow 127.1.0.4 "RSS"
+.irow 127.1.0.5 "RSS and RBL"
+.irow 127.1.0.6 "RSS and DUL"
+.irow 127.1.0.7 "RSS and DUL and RBL"
+.endtable
Section &<>& below describes how you can distinguish between
different values. Some DNS lists may return more than one address record;
see section &<>& for details of how they are checked.
-.new
Values returned by a properly running DBSBL should be in the 127.0.0.0/8
range. If a DNSBL operator loses control of the domain, lookups on it
may start returning other addresses. Because of this, Exim now ignores
returned values outside the 127/8 region.
-.wen
.section "Variables set from DNS lists" "SECID204"
@@ -33049,6 +33122,63 @@ address you should specify alternate list separators for both the outer
dnslists = <; dnsbl.example.com/<|$acl_m_addrslist
.endd
+
+.new
+.section "Previously seen user and hosts" "SECTseen"
+.cindex "&%sseen%& ACL condition"
+.cindex greylisting
+The &%seen%& ACL condition can be used to test whether a
+situation has been previously met.
+It uses a hints database to record a timestamp against a key.
+host. The syntax of the condition is:
+.display
+&`seen =`& <&'optional flag'&><&'time interval'&> &`/`& <&'options'&>
+.endd
+
+For example,
+.code
+defer seen = -5m / key=${sender_host_address}_$local_part@$domain
+.endd
+in a RCPT ACL will implement simple greylisting.
+
+The parameters for the condition are
+a possible minus sign,
+then an interval,
+then, slash-separated, a list of options.
+The interval is taken as an offset before the current time,
+and used for the test.
+If the interval is preceded by a minus sign then the condition returns
+whether a record is found which is before the test time.
+Otherwise, the condition returns whether one is found which is since the
+test time.
+
+Options are read in order with later ones overriding earlier ones.
+
+The default key is &$sender_host_address$&.
+An explicit key can be set using a &%key=value%& option.
+
+If a &%readonly%& option is given then
+no record create or update is done.
+If a &%write%& option is given then
+a record create or update is always done.
+An update is done if the test is for &"since"&.
+If none of those hold and there was no existing record,
+a record is created.
+
+Creates and updates are marked with the current time.
+
+Finally, a &"before"& test which succeeds, and for which the record
+is old enough, will be refreshed with a timestamp of the test time.
+This can prevent tidying of the database from removing the entry.
+The interval for this is, by default, 10 days.
+An explicit interval can be set using a
+&%refresh=value%& option.
+
+Note that &"seen"& should be added to the list of hints databases
+for maintenance if this ACL condition is used.
+.wen
+
+
.section "Rate limiting incoming messages" "SECTratelimiting"
.cindex "rate limiting" "client sending"
.cindex "limiting client sending rates"
@@ -33354,7 +33484,6 @@ The &%success_on_redirect%& option causes verification always to succeed
immediately after a successful redirection. By default, if a redirection
generates just one address, that address is also verified. See further
discussion in section &<>&.
-.new
.next
If the &%quota%& option is specified for recipient verify,
successful routing to an appendfile transport is followed by a call into
@@ -33362,7 +33491,6 @@ the transport to evaluate the quota status for the recipient.
No actual delivery is done, but verification will succeed if the quota
is sufficient for the message (if the sender gave a message size) or
not already exceeded (otherwise).
-.wen
.endlist
.cindex "verifying address" "differentiating failures"
@@ -33397,7 +33525,6 @@ connection, HELO, or MAIL).
&%recipient%&: The RCPT command in a callout was rejected.
.next
&%postmaster%&: The postmaster check in a callout was rejected.
-.new
.next
&%quota%&: The quota check for a local recipient did non pass.
.endlist
@@ -33494,6 +33621,15 @@ output before performing a callout in an ACL, to avoid unexpected timeouts in
clients when the SMTP PIPELINING extension is in use. The flushing can be
disabled by using a &%control%& modifier to set &%no_callout_flush%&.
+.new
+.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using receipient verify"
+A recipient callout which gets a 2&'xx'& code
+will assign untainted values to the
+&$domain_data$& and &$local_part_data$& variables,
+corresponding to the domain and local parts of the recipient address.
+.wen
+
@@ -33729,7 +33865,6 @@ behaviour will be the same.
-.new
.section "Quota caching" "SECTquotacache"
.cindex "hints database" "quota cache"
.cindex "quota" "cache, description of"
@@ -33759,7 +33894,6 @@ As above, for a negative entry.
.vitem &*no_cache*&
Set both positive and negative lifetimes to zero.
-.wen
.section "Sender address verification reporting" "SECTsenaddver"
.cindex "verifying" "suppressing error details"
@@ -35322,8 +35456,10 @@ discussed below.
.vitem &*header_line&~*header_last*&
A pointer to the last of the header lines.
-.vitem &*uschar&~*headers_charset*&
+.new
+.vitem &*const&~uschar&~*headers_charset*&
The value of the &%headers_charset%& configuration option.
+.wen
.vitem &*BOOL&~host_checking*&
This variable is TRUE during a host checking session that is initiated by the
@@ -35607,11 +35743,11 @@ added zero byte is not included in the returned count.
.vitem &*int&~lss_match_domain(uschar&~*domain,&~uschar&~*list)*&
This function checks for a match in a domain list. Domains are always
matched caselessly. The return value is one of the following:
-.display
-&`OK `& match succeeded
-&`FAIL `& match failed
-&`DEFER `& match deferred
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow &`OK`& "match succeeded"
+.irow &`FAIL`& "match failed"
+.irow &`DEFER`& "match deferred"
+.endtable
DEFER is usually caused by some kind of lookup defer, such as the
inability to contact a database.
@@ -38504,16 +38640,16 @@ One line is written to the main log for each message received, and for each
successful, unsuccessful, and delayed delivery. These lines can readily be
picked out by the distinctive two-character flags that immediately follow the
timestamp. The flags are:
-.display
-&`<=`& message arrival
-&`(=`& message fakereject
-&`=>`& normal message delivery
-&`->`& additional address in same delivery
-&`>>`& cutthrough message delivery
-&`*>`& delivery suppressed by &%-N%&
-&`**`& delivery failed; address bounced
-&`==`& delivery deferred; temporary problem
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow &%<=%& "message arrival"
+.irow &%(=%& "message fakereject"
+.irow &%=>%& "normal message delivery"
+.irow &%->%& "additional address in same delivery"
+.irow &%>>%& "cutthrough message delivery"
+.irow &%*>%& "delivery suppressed by &%-N%&"
+.irow &%**%& "delivery failed; address bounced"
+.irow &%==%& "delivery deferred; temporary problem"
+.endtable
.section "Logging message reception" "SECID251"
@@ -38629,9 +38765,7 @@ When more than one address is included in a single delivery (for example, two
SMTP RCPT commands in one transaction) the second and subsequent addresses are
flagged with &`->`& instead of &`=>`&. When two or more messages are delivered
down a single SMTP connection, an asterisk follows the
-.new
remote IP address (and port if enabled)
-.wen
in the log lines for the second and subsequent messages.
When two or more messages are delivered down a single TLS connection, the
DNS and some TLS-related information logged for the first message delivered
@@ -38834,66 +38968,64 @@ log_selector = +arguments -retry_defer
.endd
The list of optional log items is in the following table, with the default
selection marked by asterisks:
-.display
-&` 8bitmime `& received 8BITMIME status
-&`*acl_warn_skipped `& skipped &%warn%& statement in ACL
-&` address_rewrite `& address rewriting
-&` all_parents `& all parents in => lines
-&` arguments `& command line arguments
-&`*connection_reject `& connection rejections
-&`*delay_delivery `& immediate delivery delayed
-&` deliver_time `& time taken to attempt delivery
-&` delivery_size `& add &`S=`&&'nnn'& to => lines
-&`*dkim `& DKIM verified domain on <= lines
-&` dkim_verbose `& separate full DKIM verification result line, per signature
-&`*dnslist_defer `& defers of DNS list (aka RBL) lookups
-&` dnssec `& DNSSEC secured lookups
-&`*etrn `& ETRN commands
-&`*host_lookup_failed `& as it says
-&` ident_timeout `& timeout for ident connection
-&` incoming_interface `& local interface on <= and => lines
-&` incoming_port `& remote port on <= lines
-&`*lost_incoming_connection `& as it says (includes timeouts)
-&` millisec `& millisecond timestamps and RT,QT,DT,D times
-&`*msg_id `& on <= lines, Message-ID: header value
-&` msg_id_created `& on <= lines, Message-ID: header value when one had to be added
-&` outgoing_interface `& local interface on => lines
-&` outgoing_port `& add remote port to => lines
-&`*queue_run `& start and end queue runs
-&` queue_time `& time on queue for one recipient
-&`*queue_time_exclusive `& exclude recieve time from QT times
-&` queue_time_overall `& time on queue for whole message
-&` pid `& Exim process id
-&` pipelining `& PIPELINING use, on <= and => lines
-&` proxy `& proxy address on <= and => lines
-&` receive_time `& time taken to receive message
-&` received_recipients `& recipients on <= lines
-&` received_sender `& sender on <= lines
-&`*rejected_header `& header contents on reject log
-&`*retry_defer `& &"retry time not reached"&
-&` return_path_on_delivery `& put return path on => and ** lines
-&` sender_on_delivery `& add sender to => lines
-&`*sender_verify_fail `& sender verification failures
-&`*size_reject `& rejection because too big
-&`*skip_delivery `& delivery skipped in a queue run
-&`*smtp_confirmation `& SMTP confirmation on => lines
-&` smtp_connection `& incoming SMTP connections
-&` smtp_incomplete_transaction`& incomplete SMTP transactions
-&` smtp_mailauth `& AUTH argument to MAIL commands
-&` smtp_no_mail `& session with no MAIL commands
-&` smtp_protocol_error `& SMTP protocol errors
-&` smtp_syntax_error `& SMTP syntax errors
-&` subject `& contents of &'Subject:'& on <= lines
-&`*taint `& taint errors or warnings
-&`*tls_certificate_verified `& certificate verification status
-&`*tls_cipher `& TLS cipher suite on <= and => lines
-&` tls_peerdn `& TLS peer DN on <= and => lines
-&` tls_resumption `& append * to cipher field
-&` tls_sni `& TLS SNI on <= lines
-&` unknown_in_list `& DNS lookup failed in list match
-
-&` all `& all of the above
-.endd
+.itable none 0 0 3 1pt left 10pt center 1pt left
+.irow &`8bitmime`& "received 8BITMIME status"
+.irow &`acl_warn_skipped`& * "skipped &%warn%& statement in ACL"
+.irow &`address_rewrite`& "address rewriting"
+.irow &`all_parents`& "all parents in => lines"
+.irow &`arguments`& "command line arguments"
+.irow &`connection_reject`& * "connection rejections"
+.irow &`delay_delivery`& * "immediate delivery delayed"
+.irow &`deliver_time`& "time taken to attempt delivery"
+.irow &`delivery_size`& "add &`S=`&&'nnn'& to => lines"
+.irow &`dkim`& * "DKIM verified domain on <= lines"
+.irow &`dkim_verbose`& "separate full DKIM verification result line, per signature"
+.irow &`dnslist_defer`& * "defers of DNS list (aka RBL) lookups"
+.irow &`dnssec`& "DNSSEC secured lookups"
+.irow &`etrn`& * "ETRN commands"
+.irow &`host_lookup_failed`& * "as it says"
+.irow &`ident_timeout`& "timeout for ident connection"
+.irow &`incoming_interface`& "local interface on <= and => lines"
+.irow &`incoming_port`& "remote port on <= lines"
+.irow &`lost_incoming_connection`& * "as it says (includes timeouts)"
+.irow &`millisec`& "millisecond timestamps and RT,QT,DT,D times"
+.irow &`msg_id`& * "on <= lines, Message-ID: header value"
+.irow &`msg_id_created`& "on <= lines, Message-ID: header value when one had to be added"
+.irow &`outgoing_interface`& "local interface on => lines"
+.irow &`outgoing_port`& "add remote port to => lines"
+.irow &`queue_run`& * "start and end queue runs"
+.irow &`queue_time`& "time on queue for one recipient"
+.irow &`queue_time_exclusive`& "exclude recieve time from QT times"
+.irow &`queue_time_overall`& "time on queue for whole message"
+.irow &`pid`& "Exim process id"
+.irow &`pipelining`& "PIPELINING use, on <= and => lines"
+.irow &`proxy`& "proxy address on <= and => lines"
+.irow &`receive_time`& "time taken to receive message"
+.irow &`received_recipients`& "recipients on <= lines"
+.irow &`received_sender`& "sender on <= lines"
+.irow &`rejected_header`& * "header contents on reject log"
+.irow &`retry_defer`& * "&&retry time not reached&
&"
+.irow &`return_path_on_delivery`& "put return path on => and ** lines"
+.irow &`sender_on_delivery`& "add sender to => lines"
+.irow &`sender_verify_fail`& * "sender verification failures"
+.irow &`size_reject`& * "rejection because too big"
+.irow &`skip_delivery`& * "delivery skipped in a queue run"
+.irow &`smtp_confirmation`& * "SMTP confirmation on => lines"
+.irow &`smtp_connection`& "incoming SMTP connections"
+.irow &`smtp_incomplete_transaction`& "incomplete SMTP transactions"
+.irow &`smtp_mailauth`& "AUTH argument to MAIL commands"
+.irow &`smtp_no_mail`& "session with no MAIL commands"
+.irow &`smtp_protocol_error`& "SMTP protocol errors"
+.irow &`smtp_syntax_error`& "SMTP syntax errors"
+.irow &`subject`& "contents of &'Subject:'& on <= lines"
+.irow &`tls_certificate_verified`& * "certificate verification status"
+.irow &`tls_cipher`& * "TLS cipher suite on <= and => lines"
+.irow &`tls_peerdn`& "TLS peer DN on <= and => lines"
+.irow &`tls_resumption`& "append * to cipher field"
+.irow &`tls_sni`& "TLS SNI on <= lines"
+.irow &`unknown_in_list`& "DNS lookup failed in list match"
+.irow &`all`& "&*all of the above*&"
+.endtable
See also the &%slow_lookup_log%& main configuration option,
section &<>&
@@ -39011,9 +39143,7 @@ to the &"<="& line as an IP address in square brackets, tagged by I= and
followed by a colon and the port number. The local interface and port are also
added to other SMTP log lines, for example, &"SMTP connection from"&, to
rejection lines, and (despite the name) to outgoing
-.new
&"=>"&, &"->"&, &"=="& and &"**"& lines.
-.wen
The latter can be disabled by turning off the &%outgoing_interface%& option.
.next
.cindex log "incoming proxy address"
@@ -39280,11 +39410,6 @@ using a CA trust anchor,
&`CV=dane`& if using a DNS trust anchor,
and &`CV=no`& if not.
.next
-.cindex "log" "Taint warnings"
-&%taint%&: Log warnings about tainted data. This selector can't be
-turned of if &%allow_insecure_tainted_data%& is false (which is the
-default).
-.next
.cindex "log" "TLS cipher"
.cindex "TLS" "logging cipher"
&%tls_cipher%&: When a message is sent or received over an encrypted
@@ -39298,11 +39423,9 @@ added to the log line, preceded by DN=.
.next
.cindex "log" "TLS resumption"
.cindex "TLS" "logging session resumption"
-.new
&%tls_resumption%&: When a message is sent or received over an encrypted
connection and the TLS session resumed one used on a previous TCP connection,
an asterisk is appended to the X= cipher field in the log line.
-.wen
.next
.cindex "log" "TLS SNI"
.cindex "TLS" "logging SNI"
@@ -39400,12 +39523,12 @@ but the format of the output is different. For this reason, there are some
system configuration options that configure exactly how &'exiwhat'& works. If
it doesn't seem to be working for you, check the following compile-time
options:
-.display
-&`EXIWHAT_PS_CMD `& the command for running &'ps'&
-&`EXIWHAT_PS_ARG `& the argument for &'ps'&
-&`EXIWHAT_EGREP_ARG `& the argument for &'egrep'& to select from &'ps'& output
-&`EXIWHAT_KILL_ARG `& the argument for the &'kill'& command
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow &`EXIWHAT_PS_CMD`& "the command for running &'ps'&"
+.irow &`EXIWHAT_PS_ARG`& "the argument for &'ps'&"
+.irow &`EXIWHAT_EGREP_ARG`& "the argument for &'egrep'& to select from &'ps'& output"
+.irow &`EXIWHAT_KILL_ARG`& "the argument for the &'kill'& command"
+.endtable
An example of typical output from &'exiwhat'& is
.code
164 daemon: -q1h, listening on port 25
@@ -39431,9 +39554,6 @@ or (in case &*-a*& switch is specified)
.code
exim -bp
.endd
-The &*-C*& option is used to specify an alternate &_exim.conf_& which might
-contain alternate exim configuration the queue management might be using.
-
to obtain a queue listing, and then greps the output to select messages
that match given criteria. The following selection options are available:
@@ -39490,7 +39610,22 @@ Display messages in reverse order.
Include delivered recipients in queue listing.
.endlist
+The following options give alternates for configuration:
+
+.vlist
+.vitem &*-C*&&~<&'config&~file'&>
+is used to specify an alternate &_exim.conf_& which might
+contain alternate exim configuration the queue management might be using.
+
+.vitem &*-E*&&~<&'path'&>
+can be used to specify a path for the exim binary,
+overriding the built-in one.
+.endlist
+
There is one more option, &%-h%&, which outputs a list of options.
+.new
+At least one selection option, or either the &*-c*& or &*-h*& option, must be given.
+.wen
@@ -39850,9 +39985,7 @@ for remote hosts
.next
&'ratelimit'&: the data for implementing the ratelimit ACL condition
.next
-.new
&'tls'&: TLS session resumption data
-.wen
.next
&'misc'&: other hints data
.endlist
@@ -39874,12 +40007,19 @@ in a transport)
.section "exim_dumpdb" "SECTdumpdb"
.cindex "&'exim_dumpdb'&"
The entire contents of a database are written to the standard output by the
-&'exim_dumpdb'& program, which has no options or arguments other than the
-spool and database names. For example, to dump the retry database:
+&'exim_dumpdb'& program,
+.new
+taking as arguments the spool and database names.
+An option &'-z'& may be given to request times in UTC;
+otherwise times are in the local timezone.
+An option &'-k'& may be given to dump only the record keys.
+.wen
+For example, to dump the retry database:
.code
exim_dumpdb /var/spool/exim retry
.endd
-Two lines of output are produced for each entry:
+For the retry database
+two lines of output are produced for each entry:
.code
T:mail.ref.example:192.168.242.242 146 77 Connection refused
31-Oct-1995 12:00:12 02-Nov-1995 12:21:39 02-Nov-1995 20:21:39 *
@@ -39961,7 +40101,7 @@ databases is likely to keep on increasing.
.cindex "&'exim_fixdb'&"
The &'exim_fixdb'& program is a utility for interactively modifying databases.
Its main use is for testing Exim, but it might also be occasionally useful for
-getting round problems in a live system. It has no options, and its interface
+getting round problems in a live system. Its interface
is somewhat crude. On entry, it prompts for input with a right angle-bracket. A
key of a database record can then be entered, and the data for that record is
displayed.
@@ -39978,6 +40118,12 @@ resets the time of the next delivery attempt. Time values are given as a
sequence of digit pairs for year, month, day, hour, and minute. Colons can be
used as optional separators.
+.new
+Both displayed and input times are in the local timezone by default.
+If an option &'-z'& is used on the command line, displayed times
+are in UTC.
+.wen
+
@@ -40748,7 +40894,7 @@ Consider the use of the &%inlisti%& expansion condition instead.
.cindex "security" "data sources"
.cindex "security" "regular expressions"
.cindex "regular expressions" "security"
-.cindex "PCRE" "security"
+.cindex "PCRE2" "security"
If configuration data for Exim can come from untrustworthy sources, there
are some issues to be aware of:
@@ -40758,7 +40904,7 @@ Use of &%${expand...}%& may provide a path for shell injection attacks.
Letting untrusted data provide a regular expression is unwise.
.next
Using &%${match...}%& to apply a fixed regular expression against untrusted
-data may result in pathological behaviour within PCRE. Be aware of what
+data may result in pathological behaviour within PCRE2. Be aware of what
"backtracking" means and consider options for being more strict with a regular
expression. Avenues to explore include limiting what can match (avoiding &`.`&
when &`[a-z0-9]`& or other character class will do), use of atomic grouping and
@@ -40999,8 +41145,18 @@ was received, in the conventional Unix form &-- the number of seconds since the
start of the epoch. The second number is a count of the number of messages
warning of delayed delivery that have been sent to the sender.
-There follow a number of lines starting with a hyphen. These can appear in any
-order, and are omitted when not relevant:
+.new
+There follow a number of lines starting with a hyphen.
+These contain variables, can appear in any
+order, and are omitted when not relevant.
+
+If there is a second hyphen after the first,
+the corresponding data is tainted.
+If there is a value in parentheses, the data is quoted for a lookup.
+
+The following word specifies a variable,
+and the remainder of the item depends on the variable.
+.wen
.vlist
.vitem "&%-acl%&&~<&'number'&>&~<&'length'&>"
@@ -41156,9 +41312,6 @@ was received from the client, this records the Distinguished Name from that
certificate.
.endlist
-Any of the above may have an extra hyphen prepended, to indicate the the
-corresponding data is untrusted.
-
Following the options there is a list of those addresses to which the message
is not to be delivered. This set of addresses is initialized from the command
line when the &%-t%& option is used and &%extract_addresses_remove_arguments%&
@@ -41362,14 +41515,12 @@ option along with &%$dkim_domain%&.
If the option is empty after expansion, DKIM signing is not done for this domain,
and no error will result even if &%dkim_strict%& is set.
-.new
To do, for example, dual-signing with RSA and EC keys
this could be be used:
.code
dkim_selector = ec_sel : rsa_sel
dkim_private_key = KEYS_DIR/$dkim_selector
.endd
-.wen
.option dkim_private_key smtp string&!! unset
This sets the private key to use.
@@ -41979,7 +42130,6 @@ The lookup will return the same result strings as can appear in
.section "SRS (Sender Rewriting Scheme)" SECTSRS
.cindex SRS "sender rewriting scheme"
-.new
SRS can be used to modify sender addresses when forwarding so that
SPF verification does not object to them.
It operates by encoding the original envelope sender in a new
@@ -42074,7 +42224,6 @@ Example usage:
.endd
-.wen
@@ -42187,16 +42336,16 @@ The &"dmarc_status"& condition takes a list of strings on its
right-hand side. These strings describe recommended action based
on the DMARC check. To understand what the policy recommendations
mean, refer to the DMARC website above. Valid strings are:
-.display
-&'accept '& The DMARC check passed and the library recommends accepting the email.
-&'reject '& The DMARC check failed and the library recommends rejecting the email.
-&'quarantine '& The DMARC check failed and the library recommends keeping it for further inspection.
-&'none '& The DMARC check passed and the library recommends no specific action, neutral.
-&'norecord '& No policy section in the DMARC record for this RFC5322.From field
-&'nofrom '& Unable to determine the domain of the sender.
-&'temperror '& Library error or dns error.
-&'off '& The DMARC check was disabled for this email.
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow &'accept'& "The DMARC check passed and the library recommends accepting the email"
+.irow &'reject'& "The DMARC check failed and the library recommends rejecting the email"
+.irow &'quarantine'& "The DMARC check failed and the library recommends keeping it for further inspection"
+.irow &'none'& "The DMARC check passed and the library recommends no specific action, neutral"
+.irow &'norecord'& "No policy section in the DMARC record for this RFC5322.From field"
+.irow &'nofrom'& "Unable to determine the domain of the sender"
+.irow &'temperror'& "Library error or dns error"
+.irow &'off'& "The DMARC check was disabled for this email"
+.endtable
You can prefix each string with an exclamation mark to invert its
meaning, for example "!accept" will match all results but
"accept". The string list is evaluated left-to-right in a
@@ -42362,13 +42511,13 @@ within &%proxy_protocol_timeout%&, which defaults to 3s.
The following expansion variables are usable
(&"internal"& and &"external"& here refer to the interfaces
of the proxy):
-.display
-&'proxy_external_address '& IP of host being proxied or IP of remote interface of proxy
-&'proxy_external_port '& Port of host being proxied or Port on remote interface of proxy
-&'proxy_local_address '& IP of proxy server inbound or IP of local interface of proxy
-&'proxy_local_port '& Port of proxy server inbound or Port on local interface of proxy
-&'proxy_session '& boolean: SMTP connection via proxy
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow $proxy_external_address "IP of host being proxied or IP of remote interface of proxy"
+.irow $proxy_external_port "Port of host being proxied or Port on remote interface of proxy"
+.irow $proxy_local_address "IP of proxy server inbound or IP of local interface of proxy"
+.irow $proxy_local_port "Port of proxy server inbound or Port on local interface of proxy"
+.irow $proxy_session "boolean: SMTP connection via proxy"
+.endtable
If &$proxy_session$& is set but &$proxy_external_address$& is empty
there was a protocol error.
The variables &$sender_host_address$& and &$sender_host_port$&
@@ -42415,15 +42564,15 @@ is an IP address and any subsequent elements are options.
Options are a string =.
The list of options is in the following table:
-.display
-&'auth '& authentication method
-&'name '& authentication username
-&'pass '& authentication password
-&'port '& tcp port
-&'tmo '& connection timeout
-&'pri '& priority
-&'weight '& selection bias
-.endd
+.itable none 0 0 2 1pt left 1pt left
+.irow &'auth'& "authentication method"
+.irow &'name'& "authentication username"
+.irow &'pass'& "authentication password"
+.irow &'port'& "tcp port"
+.irow &'tmo'& "connection timeout"
+.irow &'pri'& "priority"
+.irow &'weight'& "selection bias"
+.endtable
More details on each of these options follows:
@@ -42539,11 +42688,11 @@ This is usually for use in a Message Submission Agent context,
but could be used for any message.
If a value is appended it may be:
-.display
-&`1 `& mandatory downconversion
-&`0 `& no downconversion
-&`-1 `& if SMTPUTF8 not supported by destination host
-.endd
+.itable none 0 0 2 1pt right 1pt left
+.irow &`1`& "mandatory downconversion"
+.irow &`0`& "no downconversion"
+.irow &`-1`& "if SMTPUTF8 not supported by destination host"
+.endtable
If no value is given, 1 is used.
If mua_wrapper is set, the utf8_downconvert control
@@ -42643,23 +42792,26 @@ Events have names which correspond to the point in process at which they fire.
The name is placed in the variable &$event_name$& and the event action
expansion must check this, as it will be called for every possible event type.
+.new
The current list of events is:
-.display
-&`dane:fail after transport `& per connection
-&`msg:complete after main `& per message
-&`msg:defer after transport `& per message per delivery try
-&`msg:delivery after transport `& per recipient
-&`msg:rcpt:host:defer after transport `& per recipient per host
-&`msg:rcpt:defer after transport `& per recipient
-&`msg:host:defer after transport `& per host per delivery try; host errors
-&`msg:fail:delivery after transport `& per recipient
-&`msg:fail:internal after main `& per recipient
-&`tcp:connect before transport `& per connection
-&`tcp:close after transport `& per connection
-&`tls:cert before both `& per certificate in verification chain
-&`smtp:connect after transport `& per connection
-&`smtp:ehlo after transport `& per connection
-.endd
+.itable all 0 0 4 1pt left 1pt center 1pt center 1pt left
+.irow dane:fail after transport "per connection"
+.irow msg:complete after main "per message"
+.irow msg:defer after transport "per message per delivery try"
+.irow msg:delivery after transport "per recipient"
+.irow msg:rcpt:host:defer after transport "per recipient per host"
+.irow msg:rcpt:defer after transport "per recipient"
+.irow msg:host:defer after transport "per host per delivery try; host errors"
+.irow msg:fail:delivery after transport "per recipient"
+.irow msg:fail:internal after main "per recipient"
+.irow tcp:connect before transport "per connection"
+.irow tcp:close after transport "per connection"
+.irow tls:cert before both "per certificate in verification chain"
+.irow tls:fail:connect after main "per connection"
+.irow smtp:connect after transport "per connection"
+.irow smtp:ehlo after transport "per connection"
+.endtable
+.wen
New event types may be added in future.
The event name is a colon-separated list, defining the type of
@@ -42675,23 +42827,24 @@ should define the event action.
An additional variable, &$event_data$&, is filled with information varying
with the event type:
-.display
-&`dane:fail `& failure reason
-&`msg:defer `& error string
-&`msg:delivery `& smtp confirmation message
-&`msg:fail:internal `& failure reason
-&`msg:fail:delivery `& smtp error message
-&`msg:host:defer `& error string
-&`msg:rcpt:host:defer `& error string
-&`msg:rcpt:defer `& error string
-&`tls:cert `& verification chain depth
-&`smtp:connect `& smtp banner
-&`smtp:ehlo `& smtp ehlo response
-.endd
+.itable all 0 0 2 1pt left 1pt left
+.irow dane:fail "failure reason"
+.irow msg:defer "error string"
+.irow msg:delivery "smtp confirmation message"
+.irow msg:fail:internal "failure reason"
+.irow msg:fail:delivery "smtp error message"
+.irow msg:host:defer "error string"
+.irow msg:rcpt:host:defer "error string"
+.irow msg:rcpt:defer "error string"
+.irow tls:cert "verification chain depth"
+.irow tls:fail:connect "error string"
+.irow smtp:connect "smtp banner"
+.irow smtp:ehlo "smtp ehlo response"
+.endtable
The :defer events populate one extra variable: &$event_defer_errno$&.
-For complex operations an ACL expansion can be used in &%event_action%&
+For complex operations an ACL expansion can be used in &%event_action%&,
however due to the multiple contexts that Exim operates in during
the course of its processing:
.ilist
@@ -42707,11 +42860,11 @@ a useful way of writing to the main log.
The expansion of the event_action option should normally
return an empty string. Should it return anything else the
following will be forced:
-.display
-&`tcp:connect `& do not connect
-&`tls:cert `& refuse verification
-&`smtp:connect `& close connection
-.endd
+.itable all 0 0 2 1pt left 1pt left
+.irow tcp:connect "do not connect"
+.irow tls:cert "refuse verification"
+.irow smtp:connect "close connection"
+.endtable
All other message types ignore the result string, and
no other use is made of it.