.set drivernamemax "64"
.macro copyyear
-2021
+2022
.endmacro
. /////////////////////////////////////////////////////////////////////////////
.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.
<secondary>failure report</secondary>
<see><emphasis>bounce message</emphasis></see>
</indexterm>
-<indexterm role="concept">
- <primary>de-tainting</primary>
- <see><emphasis>tainting, de-tainting</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>detainting</primary>
- <see><emphasis>tainting, de-tainting</emphasis></see>
-</indexterm>
<indexterm role="concept">
<primary>dialup</primary>
<see><emphasis>intermittently connected hosts</emphasis></see>
.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
.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
.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
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
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
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"
All single-key lookups support the option &"ret=key"&.
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
notation before executing the lookup.)
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.
.next
.cindex expansion "tainted data"
and expansion of data deriving from the sender (&"tainted data"&)
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.
Common ways of obtaining untainted equivalents of variables with
tainted values
This item inserts &"raw"& header lines. It is described with the &%header%&
expansion item in section &<<SECTexpansionitems>>& 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
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.
-.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
-${substr_<n>_<m>:<string>}
+${substr_<n>_<m>:<subject>}
.endd
The second number is optional (in both notations).
If it is absent in the simpler format, the preceding underscore must also be
${if forany{fOo:NeeDLE:bAr}{eqi{$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"
+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$& is restored after the if.
+.wen
+
+
.vitem &*isip&~{*&<&'string'&>&*}*& &&&
&*isip4&~{*&<&'string'&>&*}*& &&&
&*isip6&~{*&<&'string'&>&*}*&
have their local parts matched casefully. Domains are always matched
caselessly.
+.new
+The variable &$value$& will be set for a successful match and can be
+used in the success clause of an &%if%& expansion item using the condition.
+.cindex "tainted data" "de-tainting"
+It will have the same taint status as the list; expansions such as
+.code
+${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.
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"
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
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 &<<SECTauthparamail>>&. Unless the data is the string
looked up, the contents of any associated TXT record, and the value from the
main A record. See section &<<SECID204>>& 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 &$domain$&.
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
deny hosts = net-lsearch;/some/file
message = $host_data
.endd
+
.vitem &$host_lookup_deferred$&
.cindex "host name" "lookup, failure of"
.vindex "&$host_lookup_deferred$&"
is an integer. For example, if the load average is 0.21, the value of the
variable is 210. The value is recomputed every time the variable is referenced.
-.vitem &$local_part$&
-.vindex "&$local_part$&"
+.tvar &$local_part$&
When an address is being routed, or delivered on its own, this
variable contains the local part. When a number of addresses are being
delivered together (for example, multiple RCPT commands in an SMTP
of seconds since the message was received. It does not change during a single
delivery attempt.
-.vitem &$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$&"
.oindex "&%message_body_visible%&"
This variable contains the initial portion of a message's body while it is
being delivered, and is intended mainly for use in filter files. The maximum
this can be disabled by setting &%message_body_newlines%& to be true. Binary
zeros are always converted into spaces.
-.vitem &$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$&.
line; it is the local id that Exim assigns to the message, for example:
&`1BXTIK-0001yO-VA`&.
-.vitem &$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$& except that no processing of the
contents of header lines is done.
These variables are counters that can be incremented by means
of the &%add%& command in filter files.
-.vitem &$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$&. However, if a &"child"& address (for example,
generated by an alias, forward, or filter file) is being processed, this
filter, it is set up with an artificial &"parent"& address. This has the local
part &'system-filter'& and the default qualify domain.
-.vitem &$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$& always contains the full local
For messages received by SMTP over TCP/IP, this is normally the uid of the Exim
user.
-.vitem &$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$&
(see above), except that it refers to the immediately preceding parent address.
(described under &%transport_filter%& in chapter &<<CHAPtransportgeneric>>&).
It cannot be used in general expansion strings, and provokes an &"unknown
variable"& error if encountered.
+.new
+&*Note*&: This value permits data supplied by a potential attacker to
+be used in the command for a &(pipe)& transport.
+Such configurations should be carefully assessed for security vulnerbilities.
+.wen
.vitem &$primary_hostname$&
.vindex "&$primary_hostname$&"
is available in the DATA ACL, the non-SMTP ACL, and while routing and
delivering.
-.vitem &$received_for$&
-.vindex "&$received_for$&"
+.tvar &$received_for$&
If there is only a single recipient address in an incoming message, this
variable contains that address when the &'Received:'& header line is being
built. The value is copied after recipient rewriting has happened, but before
The main use of this variable is expected to be to distinguish between
rejections of MAIL and rejections of RCPT.
-.vitem &$recipients$&
-.vindex "&$recipients$&"
+.tvar &$recipients$&
This variable contains a list of envelope recipients for a message. A comma and
a space separate the addresses in the replacement text. However, the variable
is not generally available, to prevent exposure of Bcc recipients in
When a &%regex%& or &%mime_regex%& ACL condition succeeds,
these variables contain the
captured substrings identified by the regular expression.
+.new
+If the subject string was tainted then so will any captured substring.
+.wen
-.vitem &$reply_address$&
-.vindex "&$reply_address$&"
+.tvar &$reply_address$&
When a message is being processed, this variable contains the contents of the
&'Reply-To:'& header line if one exists and it is not empty, or otherwise the
contents of the &'From:'& header line. Apart from the removal of leading
happens, &$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$&
When a message is being processed, this variable contains the sender's address
that was received in the message's envelope. The case of letters in the address
is retained, in both the local part and the domain. For bounce messages, the
after the end of the current ACL statement. If you want to preserve it for
longer, you can save it in an ACL variable.
-.vitem &$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$&
.cindex "DNS" "DNSSEC"
done using DNS information the resolver library stated was authenticated data.
-.vitem &$sender_helo_name$&
-.vindex "&$sender_helo_name$&"
+.tvar &$sender_helo_name$&
When a message is received from a remote host that has issued a HELO or EHLO
command, the argument of that command is placed in this variable. It is also
set if HELO or EHLO is used when a message is received using SMTP locally via
is known to currently ignore EDNS0, documented in CAVEATS of asr_run(3).
-.vitem &$sender_host_name$&
-.vindex "&$sender_host_name$&"
+.tvar &$sender_host_name$&
When a message is received from a remote host, this variable contains the
host's name as obtained by looking up its IP address. For messages received by
other means, this variable is empty.
&$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$&
During the processing of an incoming SMTP command, this variable contains the
entire command. This makes it possible to distinguish between HELO and EHLO in
the HELO ACL, and also to distinguish between commands such as these:
rewriting, whereas the values in &$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$&, this variable is
Observability for TLS session resumption. See &<<SECTresumption>>& for details.
-.vitem &$tls_in_sni$&
-.vindex "&$tls_in_sni$&"
+.tvar &$tls_in_sni$&
.vindex "&$tls_sni$&"
.cindex "TLS" "Server Name Indication"
.cindex "TLS" SNI
.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"
configuration). This &"magic string"& matches the domain literal form of all
the local host's IP addresses.
-.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.
-
-
-
.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
.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.
(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,
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
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
Exim, and each argument is separately expanded, as described in section
&<<SECThowcommandrun>>& 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"
.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
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
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$& variable
+will be useful for such work.
+.wen
+
.option hosts smtp "string list&!!" unset
Hosts are associated with an address by a router such as &(dnslookup)&, which
finds the hosts by looking up the address domain in the DNS, or by
See also the &%pipelining_connect_advertise_hosts%& main option.
Note:
-When the facility is used, the transport &%helo_data%& option
+.new
+When the facility is used, if the transport &%interface%& option is unset
+the &%helo_data%& option
+.wen
will be expanded before the &$sending_ip_address$& variable
is filled in.
A check is made for the use of that variable, without the
only point of caution. The &$tls_out_sni$& variable will be set to this string
for the lifetime of the client connection (including during authentication).
+.new
If DANE validated the connection attempt then the value of the &%tls_sni%& option
-is forced to the domain part of the recipient address.
+is forced to the name of the destination host, after any MX- or CNAME-following.
+.wen
Except during SMTP client sessions, if &$tls_in_sni$& is set then it is a string
received from a client.
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"
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 $*now*
+ take effect immediately; one of &*paniclog*& triggers
+ on a write to the panic log.
+.endd
+
Some examples (which depend on variables that don't exist in all
contexts):
.code
control = debug/opts=+expand+acl
control = debug/tag=.$message_exim_id/opts=+expand
control = debug/kill
+ control = debug/opts=+all/pretrigger=1024/trigger=paniclog
+ control = debug/trigger=now
.endd
It uses a hints database to record a timestamp against a key.
host. The syntax of the condition is:
.display
-&`seen =`& <&'time interval'&> &`/`& <&'options'&>
+&`seen =`& <&'optional flag'&><&'time interval'&> &`/`& <&'options'&>
.endd
For example,
.endd
in a RCPT ACL will implement simple greylisting.
-The parameters for the condition
-are an interval followed, slash-separated, by a list of options.
+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
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.
&` 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
&`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
.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:
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
&'exim_dumpdb'& program,
.new
taking as arguments the spool and database names.
-An option &'-z'& may be given to regest times in UTC;
+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
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'&>"
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%&
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
&`tcp:connect before transport `& per connection
&`tcp:close after transport `& per connection
&`tls:cert before both `& per certificate in verification chain
+&`tls:fail:connect after main `& per connection
&`smtp:connect after transport `& per connection
&`smtp:ehlo after transport `& per connection
.endd
+.wen
New event types may be added in future.
The event name is a colon-separated list, defining the type of
&`msg:rcpt:host:defer `& error string
&`msg:rcpt:defer `& error string
&`tls:cert `& verification chain depth
+&`tls:fail:connect `& error string
&`smtp:connect `& smtp banner
&`smtp:ehlo `& smtp ehlo response
.endd
git://git.exim.org / exim.git / blobdiff