. the <bookinfo> element must also be updated for each new edition.
. /////////////////////////////////////////////////////////////////////////////
-.set previousversion "4.71"
-.set version "4.72"
+.set previousversion "4.72"
+.set version "4.73"
.set ACL "access control lists (ACLs)"
.set I " "
<author><firstname>Exim</firstname><surname>Maintainers</surname></author>
<authorinitials>EM</authorinitials>
<revhistory><revision>
- <revnumber>4.72</revnumber>
- <date>29 May 2010</date>
+ <revnumber>4.73</revnumber>
+ <date>19 Nov 2010</date>
<authorinitials>EM</authorinitials>
</revision></revhistory>
<copyright><year>2009</year><holder>University of Cambridge</holder></copyright>
.section "Use of tcpwrappers" "SECID27"
+.new
.cindex "tcpwrappers, building Exim to support"
.cindex "USE_TCP_WRAPPERS"
.cindex "TCP_WRAPPERS_DAEMON_NAME"
in &_Local/Makefile_&, or by setting tcp_wrappers_daemon_name in the
configure file. Consult the &'tcpwrappers'& documentation for
further details.
-
+.wen
.section "Including support for IPv6" "SECID28"
The same output is generated if the Exim binary is called with no options and
no arguments.
+.new
.vitem &%--version%&
.oindex "&%--version%&"
This option is an alias for &%-bV%& and causes version information to be
displayed.
+.wen
.vitem &%-B%&<&'type'&>
.oindex "&%-B%&"
Exim behaves in exactly the same way as it does when receiving a message via
the listening daemon.
+.new
.vitem &%-bmalware%&&~<&'filename'&>
.oindex "&%-bmalware%&"
.cindex "testing", "malware"
The &%-bmalware%& option will not be extended to be more generally useful,
there are better tools for file-scanning. This option exists to help
administrators verify their Exim and AV scanner configuration.
+.wen
.vitem &%-bt%&
.oindex "&%-bt%&"
than a recipient address. This affects any rewriting and qualification that
might happen.
+.new
.vitem &%-C%&&~<&'filelist'&>
.oindex "&%-C%&"
.cindex "configuration file" "alternate"
When this option is used by a caller other than root, and the list is different
from the compiled-in list, Exim gives up its root privilege immediately, and
runs with the real and effective uid and gid set to those of the caller.
-However, if a TRUSTED_CONFIG_PREFIX_LIST file is defined in &_Local/Makefile_&,
-root privilege is retained for any configuration file which matches a prefix
-listed in that file.
-
-Leaving TRUSTED_CONFIG_PREFIX_LIST unset precludes the possibility of testing
-a configuration using &%-C%& right through message reception and delivery,
+However, if a TRUSTED_CONFIG_LIST file is defined in &_Local/Makefile_&, that
+file contains a list of full pathnames, one per line, for configuration files
+which are trusted. Root privilege is retained for any configuration file so
+listed, as long as the caller is the Exim user (or the user specified in the
+CONFIGURE_OWNER option, if any), and as long as the configuration file is
+not writeable by inappropriate users or groups.
+
+Leaving TRUSTED_CONFIG_LIST unset precludes the possibility of testing a
+configuration using &%-C%& right through message reception and delivery,
even if the caller is root. The reception works, but by that time, Exim is
running as the Exim user, so when it re-executes to regain privilege for the
delivery, the use of &%-C%& causes privilege to be lost. However, root can
caller is privileged, or unless it is an exotic configuration that does not
require privilege. No check is made on the owner or group of the files
specified by this option.
+.wen
+.new
.vitem &%-D%&<&'macro'&>=<&'value'&>
.oindex "&%-D%&"
.cindex "macro" "setting on command line"
If DISABLE_D_OPTION is defined in &_Local/Makefile_&, the use of &%-D%& is
completely disabled, and its use causes an immediate error exit.
+If WHITELIST_D_MACROS is defined in &_Local/Makefile_& then it should be a
+colon-separated list of macros which are considered safe and, if &%-D%& only
+supplies macros from this list, and the values are acceptable, then Exim will
+not give up root privilege if the caller is root, the Exim run-time user, or
+the CONFIGURE_OWNER, if set. This is a transition mechanism and is expected
+to be removed in the future. Acceptable values for the macros satisfy the
+regexp: &`^[A-Za-z0-9_/.-]*$`&
+
The entire option (including equals sign if present) must all be within one
command line item. &%-D%& can be used to set the value of a macro to the empty
string, in which case the equals sign is optional. These two commands are
exim '-D ABC = something' ...
.endd
&%-D%& may be repeated up to 10 times on a command line.
+.wen
.vitem &%-d%&<&'debug&~options'&>
.oindex "&%-d%&"
give a colon-separated list of file names, in which case Exim uses the first
existing file in the list.
+.new
.cindex "EXIM_USER"
.cindex "EXIM_GROUP"
.cindex "CONFIGURE_OWNER"
CONFIGURE_FILE is a list, no default is automatically installed. Chapter
&<<CHAPdefconfil>>& is a &"walk-through"& discussion of the default
configuration.
-
+.wen
.section "Using a different configuration file" "SECID40"
option, which may specify a single file or a list of files. However, when
&%-C%& is used, Exim gives up its root privilege, unless called by root (or
unless the argument for &%-C%& is identical to the built-in value from
-CONFIGURE_FILE) or matches a prefix listed in the TRUSTED_CONFIG_PREFIX_LIST
-file. &%-C%& is useful mainly for checking the syntax of configuration files
-before installing them. No owner or group checks are done on a configuration
-file specified by &%-C%&, if root privilege has been dropped.
+CONFIGURE_FILE), or is listed in the TRUSTED_CONFIG_LIST file and the caller
+is the Exim user or the user specified in the CONFIGURE_OWNER setting. &%-C%&
+is useful mainly for checking the syntax of configuration files before
+installing them. No owner or group checks are done on a configuration file
+specified by &%-C%&, if root privilege has been dropped.
Even the Exim user is not trusted to specify an arbitrary configuration file
with the &%-C%& option to be used with root privileges, unless that file is
-listed in the TRUSTED_CONFIG_PREFIX_LIST file. This locks out the possibility
-of testing a configuration using &%-C%& right through message reception and
+listed in the TRUSTED_CONFIG_LIST file. This locks out the possibility of
+testing a configuration using &%-C%& right through message reception and
delivery, even if the caller is root. The reception works, but by that time,
Exim is running as the Exim user, so when it re-execs to regain privilege for
the delivery, the use of &%-C%& causes privilege to be lost. However, root
If DISABLE_D_OPTION is defined in &_Local/Makefile_&, the use of &%-D%& is
completely disabled, and its use causes an immediate error exit.
+.new
+The WHITELIST_D_MACROS option in &_Local/Makefile_& permits the binary builder
+to declare certain macro names trusted, such that root privilege will not
+necessarily be discarded.
+WHITELIST_D_MACROS defines a colon-separated list of macros which are
+considered safe and, if &%-D%& only supplies macros from this list, and the
+values are acceptable, then Exim will not give up root privilege if the caller
+is root, the Exim run-time user, or the CONFIGURE_OWNER, if set. This is a
+transition mechanism and is expected to be removed in the future. Acceptable
+values for the macros satisfy the regexp: &`^[A-Za-z0-9_/.-]*$`&
+.wen
+
Some sites may wish to use the same Exim binary on different machines that
share a file system, but to use different configuration files on each machine.
If CONFIGURE_FILE_USE_NODE is defined in &_Local/Makefile_&, Exim first
It is permitted to specify a space as the separator character. Further
white space is ignored.
-.new
.cindex "TXT record" "in &(dnsdb)& lookup"
For TXT records with multiple items of data, only the first item is returned,
unless a separator for them is specified using a comma after the separator
.endd
It is permitted to specify a space as the separator character. Further
white space is ignored.
-.wen
.section "Pseudo dnsdb record types" "SECID66"
.cindex "MX record" "in &(dnsdb)& lookup"
random().
+.new
.vitem &*${reverse_ip:*&<&'ipaddr'&>&*}*&
.cindex "expansion" "IP address"
This operator reverses an IP address; for IPv4 addresses, the result is in
.code
4.2.0.192 and 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
.endd
+.wen
.vitem &*${rfc2047:*&<&'string'&>&*}*&
As a special case, the numerical value of an empty string is taken as
zero.
+
+.new
.vitem &*bool&~{*&<&'string'&>&*}*&
.cindex "expansion" "boolean parsing"
.cindex "&%bool%& expansion condition"
.code
${if bool{$acl_m_privileged_sender} ...
.endd
+.wen
+
.vitem &*bool_lax&~{*&<&'string'&>&*}*&
.cindex "expansion" "boolean parsing"
the generic transport option &%message_size_limit%&, which limits the size of
message that an individual transport can process.
+.new
If you use a virus-scanner and set this option to to a value larger than the
maximum size that your virus-scanner is configured to support, you may get
failures triggered by large mails. The right size to configure for the
probably safest to just set it to a little larger than this value. Eg, with a
default Exim message size of 50M and a default ClamAV StreamMaxLength of 10M,
some problems may result.
+.wen
.option move_frozen_messages main boolean false
transport driver.
+.new
.option openssl_options main "string list" +dont_insert_empty_fragments
.cindex "OpenSSL "compatibility options"
This option allows an administrator to adjust the SSL options applied
.code
openssl_options = -all +microsoft_big_sslv3_buffer
.endd
+.wen
.option oracle_servers main "string list" unset
This specifies the transport driver that is to be used when a &%mail%& command
is used in a system filter.
+.new
.option system_filter_user main string unset
.cindex "uid (user id)" "system filter"
If this option is set to root, the system filter is run in the main Exim
If the system filter generates any pipe, file, or reply deliveries, the uid
under which the filter is run is used when transporting them, unless a
transport option overrides.
+.wen
.option tcp_nodelay main boolean true
If the result is any other value, the router is run (as this is the last
precondition to be evaluated, all the other preconditions must be true).
+.new
This option is unique in that multiple &%condition%& options may be present.
All &%condition%& options must succeed.
+.wen
The &%condition%& option provides a means of applying custom conditions to the
running of routers. Note that in the case of a simple conditional expansion,
.code
condition = ${if >{$message_age}{600}{true}{}}
.endd
+.new
A multiple condition example, which succeeds:
.code
condition = ${if >{$message_age}{600}}
condition = ${if !eq{${lc:$local_part}}{postmaster}}
condition = foobar
.endd
+.wen
If the expansion fails (other than forced failure) delivery is deferred. Some
of the other precondition options are common special cases that could in fact
be specified using &%condition%&.
apply to a command specified as a transport filter.
+.new
.option permit_coredump pipe boolean false
Normally Exim inhibits core-dumps during delivery. If you have a need to get
a core-dump of a pipe command, enable this command. This enables core-dumps
resource consumption can be quite high. Note also that Exim is typically
installed as a setuid binary and most operating systems will inhibit coredumps
of these by default, so further OS-specific action may be required.
+.wen
.option pipe_as_creator pipe boolean false
Notice that we put back the lower cased version afterwards, assuming that
is what is wanted for subsequent tests.
+.new
.vitem &*control&~=&~debug/*&<&'options'&>
.cindex "&ACL;" "enabling debug logging"
.cindex "debugging" "enabling from an ACL"
control = debug/opts=+expand+acl
control = debug/tag=.$message_exim_id/opts=+expand
.endd
+.wen
.vitem &*control&~=&~enforce_sync*& &&&
&*control&~=&~no_enforce_sync*&
use the &%demime%& condition (see section &<<SECTdemimecond>>&) before the
&%malware%& condition.
+.new
Beware the interaction of Exim's &%message_size_limit%& with any size limits
imposed by your anti-virus scanner.
+.wen
Here is a very simple scanning example:
.code
&%spam%& condition for its side effects (see the variables below), you can make
it always return &"true"& by appending &`:true`& to the username.
+.new
.cindex "spam scanning" "returned variables"
When the &%spam%& condition is run, it sets up a number of expansion
variables. These variables are saved with the received message, thus they are
available for use at delivery time.
+.wen
.vlist
.vitem &$spam_score$&
into the Exim account from running a privileged Exim with an arbitrary
configuration file, and using it to break into other accounts.
.next
-If a non-trusted configuration file (i.e. the default configuration file or
-one which is trusted by virtue of matching a prefix listed in the
-TRUSTED_CONFIG_PREFIX_LIST file) is specified with &%-C%&, or if macros are
-given with &%-D%&, then root privilege is retained only if the caller of Exim
-is root. This locks out the possibility of testing a configuration using &%-C%&
+.new
+If a non-trusted configuration file (i.e. not the default configuration file
+or one which is trusted by virtue of being listed in the TRUSTED_CONFIG_LIST
+file) is specified with &%-C%&, or if macros are given with &%-D%& (but see
+the next item), then root privilege is retained only if the caller of Exim is
+root. This locks out the possibility of testing a configuration using &%-C%&
right through message reception and delivery, even if the caller is root. The
reception works, but by that time, Exim is running as the Exim user, so when
it re-execs to regain privilege for the delivery, the use of &%-C%& causes
privilege to be lost. However, root can test reception and delivery using two
separate commands.
+.wen
+.next
+The WHITELIST_D_MACROS build option declares some macros to be safe to override
+with &%-D%& if the real uid is one of root, the Exim run-time user or the
+CONFIGURE_OWNER, if defined. The potential impact of this option is limited by
+requiring the run-time value supplied to &%-D%& to match a regex that errs on
+the restrictive side. Requiring build-time selection of safe macros is onerous
+but this option is intended solely as a transition mechanism to permit
+previously-working configurations to continue to work after release 4.73.
.next
If DISABLE_D_OPTION is defined, the use of the &%-D%& command line option
is disabled.
If the &%-C%& option is used to specify an alternate configuration file, or if
the &%-D%& option is used to define macro values for the configuration, and the
calling process is not running as root, the uid and gid are changed to those of
- the calling process.
+the calling process.
However, if DISABLE_D_OPTION is defined in &_Local/Makefile_&, the &%-D%&
option may not be used at all.
+If WHITELIST_D_MACROS is defined in &_Local/Makefile_&, then some macro values
+can be supplied if the calling process is running as root, the Exim run-time
+user or CONFIGURE_OWNER, if defined.
.next
.oindex "&%-be%&"
.oindex "&%-bf%&"
git://git.exim.org / users / jgh / exim.git / blobdiff