X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/e41be3f6bf1f53f9e9f858320ad1ac62dc86930c..exim-4_82_RC5:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index ac95f2680..ec01e1669 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -52,7 +52,7 @@ .set I "    " .macro copyyear -2012 +2013 .endmacro . ///////////////////////////////////////////////////////////////////////////// @@ -179,12 +179,7 @@ EximMaintainers EM - -.version - - -.fulldate - +.versiondatexml EM @@ -544,7 +539,6 @@ The &_.bz2_& file is usually a lot smaller than the &_.gz_& file. .cindex "distribution" "signing details" .cindex "distribution" "public key" .cindex "public key for signed distribution" -.new The distributions will be PGP signed by an individual key of the Release Coordinator. This key will have a uid containing an email address in the &'exim.org'& domain and will have signatures from other people, including @@ -558,6 +552,11 @@ At time of last update, releases were being made by Phil Pennock and signed with key &'0x403043153903637F'&, although that key is expected to be replaced in 2013. A trust path from Nigel's key to Phil's can be observed at &url(https://www.security.spodhuis.org/exim-trustpath). + +.new +Releases have also been authorized to be performed by Todd Lyons who signs with +key &'0xC4F4F94804D29EBA'&. A direct trust path exists between previous RE Phil +Pennock and Todd Lyons through a common associate. .wen The signatures for the tar bundles are in: @@ -872,12 +871,14 @@ SOFTWARE. .endblockquote .next +.new .cindex "opendmarc" "acknowledgment" The DMARC implementation uses the OpenDMARC library which is Copyrighted by The Trusted Domain Project. Portions of Exim source which use OpenDMARC derived code are indicated in the respective source files. The full OpenDMARC license is provided in the LICENSE.opendmarc file contained in the distributed source code. +.wen .next Many people have contributed code fragments, some large, some small, that were @@ -1381,8 +1382,7 @@ Setting the &%verify%& option actually sets two options, &%verify_sender%& and &%verify_recipient%&, which independently control the use of the router for sender and recipient verification. You can set these options directly if you want a router to be used for only one type of verification. -Note that cutthrough delivery is classed as a recipient verification -for this purpose. +.new "Note that cutthrough delivery is classed as a recipient verification for this purpose." .next If the &%address_test%& option is set false, the router is skipped when Exim is run with the &%-bt%& option to test an address routing. This can be helpful @@ -1392,7 +1392,7 @@ having to simulate the effect of the scanner. .next Routers can be designated for use only when verifying an address, as opposed to routing it for delivery. The &%verify_only%& option controls this. -Again, cutthrough delibery counts as a verification. +.new "Again, cutthrough delivery counts as a verification." .next Individual routers can be explicitly skipped when running the routers to check an address given in the SMTP EXPN command (see the &%expn%& option). @@ -4012,11 +4012,13 @@ routing problem. Once &%-N%& has been used for a delivery attempt, it sticks to the message, and applies to any subsequent delivery attempts that may happen for that message. +.new .vitem &%-n%& .oindex "&%-n%&" This option is interpreted by Sendmail to mean &"no aliasing"&. For normal modes of operation, it is ignored by Exim. When combined with &%-bP%& it suppresses the name of an option from being output. +.wen .vitem &%-O%&&~<&'data'&> .oindex "&%-O%&" @@ -6947,6 +6949,7 @@ has two space-separated fields: an authorization code and a target host name. The authorization code can be &"Y"& for yes, &"N"& for no, &"X"& for explicit authorization required but absent, or &"?"& for unknown. +.new .cindex "A+" "in &(dnsdb)& lookup" The pseudo-type A+ performs an A6 lookup (if configured) followed by an AAAA and then an A lookup. All results are returned; defer processing @@ -6954,6 +6957,7 @@ and then an A lookup. All results are returned; defer processing .code ${lookup dnsdb {>; a+=$sender_helo_name}} .endd +.wen .section "Multiple dnsdb lookups" "SECID67" @@ -8268,10 +8272,13 @@ apply to temporary DNS errors, whose handling is described in the next section. .cindex "&`+include_unknown`&" .cindex "&`+ignore_unknown`&" -By default, Exim behaves as if the host does not match the list. This may not -always be what you want to happen. To change Exim's behaviour, the special -items &`+include_unknown`& or &`+ignore_unknown`& may appear in the list (at -top level &-- they are not recognized in an indirected file). +Exim parses a host list from left to right. If it encounters a permanent +lookup failure in any item in the host list before it has found a match, +Exim treats it as a failure and the default behavior is as if the host +does not match the list. This may not always be what you want to happen. +To change Exim's behaviour, the special items &`+include_unknown`& or +&`+ignore_unknown`& may appear in the list (at top level &-- they are +not recognized in an indirected file). .ilist If any item that follows &`+include_unknown`& requires information that @@ -8299,6 +8306,39 @@ Both &`+include_unknown`& and &`+ignore_unknown`& may appear in the same list. The effect of each one lasts until the next, or until the end of the list. +.new +To explain the host/ip processing logic a different way for the same ACL: + +.ilist +If you have name lookups or wildcarded host names and +IP addresses in the same host list, you should normally put the IP +addresses first. For example, in an ACL you could have: +.code +accept hosts = 10.9.8.7 : *.friend.example +.endd +The reason you normally would order it this way lies in the +left-to-right way that Exim processes lists. It can test IP addresses +without doing any DNS lookups, but when it reaches an item that requires +a host name, it fails if it cannot find a host name to compare with the +pattern. If the above list is given in the opposite order, the +&%accept%& statement fails for a host whose name cannot be found, even +if its IP address is 10.9.8.7. + +.next +If you really do want to do the name check first, and still recognize the IP +address, you can rewrite the ACL like this: +.code +accept hosts = *.friend.example +accept hosts = 10.9.8.7 +.endd +If the first &%accept%& fails, Exim goes on to try the second one. See chapter +&<>& for details of ACLs. Alternatively, you can use +&`+ignore_unknown`&, which was discussed in depth in the first example in +this section. +.endlist +.wen + + .section "Temporary DNS errors when looking up host information" &&& "SECTtemdnserr" @@ -8803,6 +8843,7 @@ This item inserts &"basic"& header lines. It is described with the &%header%& expansion item below. +.new .vitem "&*${acl{*&<&'name'&>&*}{*&<&'arg'&>&*}...}*&" .cindex "expansion" "calling an acl" .cindex "&%acl%&" "call from expansion" @@ -8817,6 +8858,7 @@ the result of the expansion. If no message is set and the ACL returns accept or deny the expansion result is an empty string. If the ACL returns defer the result is a forced-fail. Otherwise the expansion fails. +.wen .vitem "&*${dlfunc{*&<&'file'&>&*}{*&<&'function'&>&*}{*&<&'arg'&>&*}&&& @@ -9449,6 +9491,7 @@ can be the word &"fail"& (not in braces) to force expansion failure if the command does not succeed. If both strings are omitted, the result is contents of the standard output/error on success, and nothing on failure. +.new .vindex "&$run_in_acl$&" The standard output/error of the command is put in the variable &$value$&. In this ACL example, the output of a command is logged for the admin to @@ -9462,6 +9505,7 @@ shell must be invoked directly, such as with: .code ${run{/bin/bash -c "/usr/bin/id >/tmp/id"}{yes}{yes}} .endd +.wen .vindex "&$runrc$&" The return code from the command is put in the variable &$runrc$&, and this @@ -9623,6 +9667,31 @@ expansion item, which extracts the working address from a single RFC2822 address. See the &*filter*&, &*map*&, and &*reduce*& items for ways of processing lists. +.new +To clarify "list of addresses in RFC 2822 format" mentioned above, Exim follows +a strict interpretation of header line formatting. Exim parses the bare, +unquoted portion of an email address and if it finds a comma, treats it as an +email address seperator. For the example header line: +.code +From: =?iso-8859-2?Q?Last=2C_First?= +.endd +The first example below demonstrates that Q-encoded email addresses are parsed +properly if it is given the raw header (in this example, &`$rheader_from:`&). +It does not see the comma because it's still encoded as "=2C". The second +example below is passed the contents of &`$header_from:`&, meaning it gets +de-mimed. Exim sees the decoded "," so it treats it as &*two*& email addresses. +The third example shows that the presence of a comma is skipped when it is +quoted. +.code +# exim -be '${addresses:From: \ +=?iso-8859-2?Q?Last=2C_First?= }' +user@example.com +# exim -be '${addresses:From: Last, First }' +Last:user@example.com +# exim -be '${addresses:From: "Last, First" }' +user@example.com +.endd +.wen .vitem &*${base62:*&<&'digits'&>&*}*& .cindex "&%base62%& expansion item" @@ -9778,13 +9847,15 @@ be useful for processing the output of the MD5 and SHA-1 hashing functions. +.new .vitem &*${hexquote:*&<&'string'&>&*}*& .cindex "quoting" "hex-encoded unprintable characters" .cindex "&%hexquote%& expansion item" This operator converts non-printable characters in a string into a hex escape form. Byte values between 33 (!) and 126 (~) inclusive are left as is, and other byte values are converted to &`\xNN`&, for example a -byt value 127 is converted to &`\x7f`&. +byte value 127 is converted to &`\x7f`&. +.wen .vitem &*${lc:*&<&'string'&>&*}*& @@ -9812,6 +9883,7 @@ See the description of the general &%length%& item above for details. Note that when &%length%& is used as an operator. +.new .vitem &*${listcount:*&<&'string'&>&*}*& .cindex "expansion" "list item count" .cindex "list" "item count" @@ -9820,15 +9892,16 @@ when &%length%& is used as an operator. The string is interpreted as a list and the number of items is returned. -.vitem &*${listnamed:*&<&'name'&>&*}*&&~and&~&*${list_*&<&'type'&>&*name*&>&*}*& +.vitem &*${listnamed:*&<&'name'&>&*}*&&~and&~&*${listnamed_*&<&'type'&>&*:*&<&'name'&>&*}*& .cindex "expansion" "named list" .cindex "&%listnamed%& expansion item" The name is interpreted as a named list and the content of the list is returned, expanding any referenced lists, re-quoting as needed for colon-separation. -If the optional type if given it must be one of "a", "d", "h" or "l" +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. +.wen .vitem &*${local_part:*&<&'string'&>&*}*& @@ -10128,6 +10201,7 @@ In all cases, a relative comparator OP is testing if <&'string1'&> OP 10M, not if 10M is larger than &$message_size$&. +.new .vitem &*acl&~{{*&<&'name'&>&*}{*&<&'arg1'&>&*}&&& {*&<&'arg2'&>&*}...}*& .cindex "expansion" "calling an acl" @@ -10142,6 +10216,7 @@ a value using a "message =" modifier the variable $value becomes the result of the expansion, otherwise it is empty. If the ACL returns accept the condition is true; if deny, false. If the ACL returns defer the result is a forced-fail. +.wen .vitem &*bool&~{*&<&'string'&>&*}*& .cindex "expansion" "boolean parsing" @@ -10337,7 +10412,7 @@ ${if forany{<, $recipients}{match{$item}{^user3@}}{yes}{no}} The value of &$item$& is saved and restored while &*forany*& or &*forall*& is being processed, to enable these expansion items to be nested. -To scan a named list, expand it with the &*listnamed*& operator. +.new "To scan a named list, expand it with the &*listnamed*& operator." .vitem &*ge&~{*&<&'string1'&>&*}{*&<&'string2'&>&*}*& &&& @@ -10882,7 +10957,18 @@ the value of &$authenticated_id$& is normally the login name of the calling process. However, a trusted user can override this by means of the &%-oMai%& command line option. - +.new +.vitem &$authenticated_fail_id$& +.cindex "authentication" "fail" "id" +.vindex "&$authenticated_fail_id$&" +When an authentication attempt fails, the variable &$authenticated_fail_id$& +will contain the failed authentication id. If more than one authentication +id is attempted, it will contain only the last one. The variable is +available for processing in the ACL's, generally the quit or notquit ACL. +A message to a local recipient could still be accepted without requiring +authentication, which means this variable could also be visible in all of +the ACL's as well. +.wen .vitem &$authenticated_sender$& @@ -11095,11 +11181,13 @@ 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 characters. Note also that braces must &'not'& be used. +.new .vitem &$headers_added$& .vindex "&$headers_added$&" Within an ACL this variable contains the headers added so far by the ACL modifier add_header (section &<>&). The headers are a newline-separated list. +.wen .vitem &$home$& .vindex "&$home$&" @@ -11771,11 +11859,13 @@ envelope sender. .vindex "&$return_size_limit$&" This is an obsolete name for &$bounce_return_size_limit$&. +.new .vitem &$router_name$& .cindex "router" "name" .cindex "name" "of router" .vindex "&$router_name$&" During the running of a router this variable contains its name. +.wen .vitem &$runrc$& .cindex "return code" "from &%run%& expansion" @@ -12091,6 +12181,7 @@ command in a filter file. Its use is explained in the description of that command, which can be found in the separate document entitled &'Exim's interfaces to mail filtering'&. +.new .vitem &$tls_in_bits$& .vindex "&$tls_in_bits$&" Contains an approximation of the TLS cipher's bit-strength @@ -12189,6 +12280,7 @@ the outbound. During outbound SMTP deliveries, this variable reflects the value of the &%tls_sni%& option on the transport. +.wen .vitem &$tod_bsdinbox$& .vindex "&$tod_bsdinbox$&" @@ -12231,11 +12323,13 @@ This variable contains the numerical value of the local timezone, for example: This variable contains the UTC date and time in &"Zulu"& format, as specified by ISO 8601, for example: 20030221154023Z. +.new .vitem &$transport_name$& .cindex "transport" "name" .cindex "name" "of transport" .vindex "&$transport_name$&" During the running of a transport, this variable contains its name. +.wen .vitem &$value$& .vindex "&$value$&" @@ -12945,7 +13039,7 @@ listed in more than one group. .section "TLS" "SECID108" .table2 .row &%gnutls_compat_mode%& "use GnuTLS compatibility mode" -.row &%gnutls_enable_pkcs11%& "allow GnuTLS to autoload PKCS11 modules" +.row &%gnutls_allow_auto_pkcs11%& "allow GnuTLS to autoload PKCS11 modules" .row &%openssl_options%& "adjust OpenSSL compatibility options" .row &%tls_advertise_hosts%& "advertise TLS to these hosts" .row &%tls_certificate%& "location of server certificate" @@ -13158,10 +13252,12 @@ A more detailed analysis of the issues is provided by Dan Bernstein: &url(http://cr.yp.to/smtp/8bitmime.html) .endd +.new To log received 8BITMIME status use .code log_selector = +8bitmime .endd +.wen .option acl_not_smtp main string&!! unset .cindex "&ACL;" "for non-SMTP messages" @@ -13981,7 +14077,7 @@ implementations of TLS. .new -option gnutls_enable_pkcs11 main boolean unset +option gnutls_allow_auto_pkcs11 main boolean unset This option will let GnuTLS (2.12.0 or later) autoload PKCS11 modules with the p11-kit configuration files in &_/etc/pkcs11/modules/_&. @@ -14742,7 +14838,9 @@ Possible options may include: .next &`no_tlsv1_2`& .next +.new &`safari_ecdhe_ecdsa_bug`& +.wen .next &`single_dh_use`& .next @@ -15337,6 +15435,13 @@ live with. . Allow this long option name to split; give it unsplit as a fifth argument . for the automatic .oindex that is generated by .option. +. We insert " &~&~" which is both pretty nasty visually and results in +. non-searchable text. HowItWorks.txt mentions an option for inserting +. zero-width-space, which would be nicer visually and results in (at least) +. html that Firefox will split on when it's forced to reflow (rather than +. inserting a horizontal scrollbar). However, the text is still not +. searchable. NM changed this occurrence for bug 1197 to no longer allow +. the option name to split. .option "smtp_accept_max_per_connection" main integer 1000 &&& smtp_accept_max_per_connection @@ -15388,10 +15493,9 @@ also &%queue_only%&, &%queue_only_load%&, &%queue_smtp_domains%&, and the various &%-od%&&'x'& command line options. -. Allow this long option name to split; give it unsplit as a fifth argument -. for the automatic .oindex that is generated by .option. +. See the comment on smtp_accept_max_per_connection -.option "smtp_accept_queue_per_ &~&~connection" main integer 10 &&& +.option "smtp_accept_queue_per_connection" main integer 10 &&& smtp_accept_queue_per_connection .cindex "queueing incoming messages" .cindex "message" "queueing by message count" @@ -16031,6 +16135,7 @@ The available primes are: Some of these will be too small to be accepted by clients. Some may be too large to be accepted by clients. +.new 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, whether too large or too small, and there's no provision for the client to @@ -16045,6 +16150,7 @@ used to set its &`DH_MAX_P_BITS`& upper-bound to 2236. This affects many mail user agents (MUAs). The lower bound comes from Debian installs of Exim4 prior to the 4.80 release, as Debian used to patch Exim to raise the minimum acceptable bound from 1024 to 2048. +.wen .option tls_on_connect_ports main "string list" unset @@ -16113,8 +16219,10 @@ use OpenSSL with a directory. See &<>& for discussion of when this option might be re-expanded. +.new A forced expansion failure or setting to an empty string is equivalent to being unset. +.wen .option tls_verify_hosts main "host list&!!" unset @@ -16654,8 +16762,10 @@ The &%headers_add%& option is expanded after &%errors_to%&, but before the expansion is forced to fail, the option has no effect. Other expansion failures are treated as configuration errors. +.new Unlike most options, &%headers_add%& can be specified multiple times for a router; all listed headers are added. +.wen &*Warning 1*&: The &%headers_add%& option cannot be used for a &(redirect)& router that has the &%one_time%& option set. @@ -17330,7 +17440,7 @@ Setting this option has the effect of setting &%verify_sender%& and .oindex "&%-bv%&" .cindex "router" "used only when verifying" If this option is set, the router is used only when verifying an address, -delivering in cutthrough mode or +.new "delivering in cutthrough mode or" testing with the &%-bv%& option, not when actually doing a delivery, testing with the &%-bt%& option, or running the SMTP EXPN command. It can be further restricted to verifying only senders or recipients by means of @@ -19653,9 +19763,10 @@ so on when debugging driver configurations. For example, if a &%headers_add%& option is not working properly, &%debug_print%& could be used to output the variables it references. A newline is added to the text if it does not end with one. +.new The variables &$transport_name$& and &$router_name$& contain the name of the transport and the router that called it. - +.wen .option delivery_date_add transports boolean false .cindex "&'Delivery-date:'& header line" @@ -19700,9 +19811,10 @@ routers. If the result of the expansion is an empty string, or if the expansion is forced to fail, no action is taken. Other expansion failures are treated as errors and cause the delivery to be deferred. +.new Unlike most options, &%headers_add%& can be specified multiple times for a transport; all listed headers are added. - +.wen .option headers_only transports boolean false @@ -21759,6 +21871,7 @@ inserted in the argument list at that point &'as a separate argument'&. This avoids any problems with spaces or shell metacharacters, and is of use when a &(pipe)& transport is handling groups of addresses in a batch. +.new If &%force_command%& is enabled on the transport, Special handling takes place for an argument that consists of precisely the text &`$address_pipe`&. It is handled similarly to &$pipe_addresses$& above. It is expanded and each @@ -21767,6 +21880,7 @@ argument is inserted in the argument list at that point the only item in the argument; in fact, if it were then &%force_command%& should behave as a no-op. Rather, it should be used to adjust the command run while preserving the argument vector separation. +.wen After splitting up into arguments and expansion, the resulting command is run in a subprocess directly from the transport, &'not'& under a shell. The @@ -21920,6 +22034,7 @@ a bounce message is sent. If &%freeze_signal%& is set, the message will be frozen in Exim's queue instead. +.new .option force_command pipe boolean false .cindex "force command" .cindex "&(pipe)& transport", "force command" @@ -21936,6 +22051,7 @@ force_command Note that &$address_pipe$& is handled specially in &%command%& when &%force_command%& is set, expanding out to the original argument vector as separate items, similarly to a Unix shell &`"$@"`& construct. +.wen .option ignore_status pipe boolean false If this option is true, the status returned by the subprocess that is set up to @@ -22298,8 +22414,10 @@ appropriate values for the outgoing connection, and these are the values that are in force when any authenticators are run and when the &%authenticated_sender%& option is expanded. +.new These variables are deprecated in favour of &$tls_in_cipher$& et. al. and will be removed in a future release. +.wen .section "Private options for smtp" "SECID146" @@ -22583,12 +22701,14 @@ that matches this list, even if the server host advertises PIPELINING support. Exim will not try to start a TLS session when delivering to any host that matches this list. See chapter &<>& for details of TLS. +.new .option hosts_verify_avoid_tls smtp "host list&!!" * .cindex "TLS" "avoiding for certain hosts" Exim will not try to start a TLS session for a verify callout, or when delivering in cutthrough mode, to any host that matches this list. Note that the default is to not use TLS. +.wen .option hosts_max_try smtp integer 5 @@ -23565,7 +23685,7 @@ In practice, almost all rules start with a domain name pattern without a local part. .cindex "regular expressions" "in retry rules" -&*Warning*&: If you use a regular expression in a routing rule pattern, it +&*Warning*&: If you use a regular expression in a retry rule pattern, it must match a complete address, not just a domain, because that is how regular expressions work in address lists. .display @@ -24175,10 +24295,12 @@ client_condition = ${if !eq{$tls_out_cipher}{}} .endd +.new .option client_set_id authenticators string&!! unset When client authentication succeeds, this condition is expanded; the result is used in the log lines for outbound messasges. Typically it will be the user name used for authentication. +.wen .option driver authenticators string unset @@ -24548,7 +24670,8 @@ to be returned. If the result of a successful expansion is an empty string, expansion is &"1"&, &"yes"&, or &"true"&, authentication succeeds and the generic &%server_set_id%& option is expanded and saved in &$authenticated_id$&. For any other result, a temporary error code is returned, with the expanded -string as the error text. +string as the error text +.new ", and the failed id saved in &$authenticated_fail_id$&." &*Warning*&: If you use a lookup in the expansion to find the user's password, be sure to make the authentication fail if the user is unknown. @@ -25732,8 +25855,10 @@ example, OpenSSL uses the name DES-CBC3-SHA for the cipher suite which in other contexts is known as TLS_RSA_WITH_3DES_EDE_CBC_SHA. Check the OpenSSL or GnuTLS documentation for more details. +.new For outgoing SMTP deliveries, &$tls_out_cipher$& is used and logged (again depending on the &%tls_cipher%& log selector). +.wen .section "Requesting and verifying client certificates" "SECID183" @@ -26024,8 +26149,10 @@ install if the receiving end is a client MUA that can interact with a user. .cindex "certificate" "self-signed" You can create a self-signed certificate using the &'req'& command provided with OpenSSL, like this: +.new . ==== Do not shorten the duration here without reading and considering . ==== the text below. Please leave it at 9999 days. +.wen .code openssl req -x509 -newkey rsa:1024 -keyout file1 -out file2 \ -days 9999 -nodes @@ -26038,6 +26165,7 @@ that you are prompted for, and any use that is made of the key causes more prompting for the passphrase. This is not helpful if you are going to use this certificate and key in an MTA, where prompting is not possible. +.new . ==== I expect to still be working 26 years from now. The less technical . ==== debt I create, in terms of storing up trouble for my later years, the . ==== happier I will be then. We really have reached the point where we @@ -26053,6 +26181,7 @@ of the certificate or reconsider your platform deployment. (At time of writing, reducing the duration is the most likely choice, but the inexorable progression of time takes us steadily towards an era where this will not be a sensible resolution). +.wen A self-signed certificate made in this way is sufficient for testing, and may be adequate for all your requirements if you are mainly interested in @@ -26252,9 +26381,10 @@ before or after the data) correctly &-- they keep the message on their queues and try again later, but that is their problem, though it does waste some of your resources. +.new The &%acl_smtp_data%& ACL is run after both the &%acl_smtp_dkim%& and the &%acl_smtp_mime%& ACLs. - +.wen .section "The SMTP DKIM ACL" "SECTDKIMACL" The &%acl_smtp_dkim%& ACL is available only when Exim is compiled with DKIM support @@ -26264,9 +26394,11 @@ The ACL test specified by &%acl_smtp_dkim%& happens after a message has been received, and is executed for each DKIM signature found in a message. If not otherwise specified, the default action is to accept. +.new This ACL is evaluated before &%acl_smtp_mime%& and &%acl_smtp_data%&. For details on the operation of DKIM, see chapter &<>&. +.wen .section "The SMTP MIME ACL" "SECID194" @@ -27102,10 +27234,12 @@ all the conditions are true, wherever it appears in an ACL command, whereas effect. +.new .vitem &*remove_header*&&~=&~<&'text'&> This modifier specifies one or more header names in a colon-separated list that are to be removed from an incoming message, assuming, of course, that the message is ultimately accepted. For details, see section &<>&. +.wen .vitem &*set*&&~<&'acl_name'&>&~=&~<&'value'&> @@ -27114,6 +27248,7 @@ This modifier puts a value into one of the ACL variables (see section &<>&). +.new .vitem &*udpsend*&&~=&~<&'parameters'&> This modifier sends a UDP packet, for purposes such as statistics collection or behaviour monitoring. The parameters are expanded, and @@ -27127,12 +27262,12 @@ when: udpsend = <; 2001:dB8::dead:beef ; 1234 ;\ $tod_zulu $sender_host_address .endd +.wen .endlist - .section "Use of the control modifier" "SECTcontrols" .cindex "&%control%& ACL modifier" The &%control%& modifier supports the following settings: @@ -27197,7 +27332,8 @@ This option requests delivery be attempted while the item is being received. It is usable in the RCPT ACL and valid only for single-recipient mails forwarded from one SMTP connection to another. If a recipient-verify callout connection is requested in the same ACL it is held open and used for the data, otherwise one is made -after the ACL completes. Note that routers are used in verify mode. +after the ACL completes. +.new "Note that routers are used in verify mode." Should the ultimate destination system positively accept or reject the mail, a corresponding indication is given to the source system and nothing is queued. @@ -27231,13 +27367,11 @@ contexts): .wen -.new .vitem &*control&~=&~dkim_disable_verify*& .cindex "disable DKIM verify" .cindex "DKIM" "disable verify" This control turns off DKIM verification processing entirely. For details on the operation and configuration of DKIM, see chapter &<>&. -.wen .new @@ -27495,7 +27629,9 @@ passing data between (for example) the MAIL and RCPT ACLs. If you want to do this, you can use ACL variables, as described in section &<>&. +.new The list of headers yet to be added is given by the &%$headers_added%& variable. +.wen The &%add_header%& modifier acts immediately as it is encountered during the processing of an ACL. Notice the difference between these two cases: @@ -27546,6 +27682,7 @@ system filter or in a router or transport. +.new .section "Removing header lines in ACLs" "SECTremoveheadacl" .cindex "header lines" "removing in an ACL" .cindex "header lines" "position of removed lines" @@ -27613,7 +27750,7 @@ are honoured. &*Warning*&: This facility currently applies only to header lines that are present during ACL processing. It does NOT remove header lines that are added in a system filter or in a router or transport. - +.wen @@ -27648,11 +27785,13 @@ condition is on a &%warn%& verb. In that case, a &"defer"& return makes the condition false. This means that further processing of the &%warn%& verb ceases, but processing of the ACL continues. +.new If the argument is a named ACL, up to nine space-separated optional values can be appended; they appear within the called ACL in $acl_arg1 to $acl_arg9, and $acl_narg is set to the count of values. Previous values of these variables are restored after the call returns. The name and values are expanded separately. +.wen If the nested &%acl%& returns &"drop"& and the outer condition denies access, the connection is dropped. If it returns &"discard"&, the verb must be @@ -28897,8 +29036,10 @@ following SMTP commands are sent: LHLO is used instead of HELO if the transport's &%protocol%& option is set to &"lmtp"&. +.new The callout may use EHLO, AUTH and/or STARTTLS given appropriate option settings. +.wen A recipient callout check is similar. By default, it also uses an empty address for the sender. This default is chosen because most hosts do not make use of @@ -29542,7 +29683,9 @@ If you do not set &%av_scanner%&, it defaults to av_scanner = sophie:/var/run/sophie .endd If the value of &%av_scanner%& starts with a dollar character, it is expanded -before use. The following scanner types are supported in this release: +before use. +The usual list-parsing of the content (see &<>&) applies. +The following scanner types are supported in this release: .vlist .vitem &%aveserver%& @@ -29568,6 +29711,7 @@ number, and a port, separated by space, as in the second of these examples: av_scanner = clamd:/opt/clamd/socket av_scanner = clamd:192.0.2.3 1234 av_scanner = clamd:192.0.2.3 1234:local +av_scanner = clamd:192.0.2.3 1234 : 192.0.2.4 1234 .endd If the value of av_scanner points to a UNIX socket file or contains the local keyword, then the ClamAV interface will pass a filename containing the data @@ -29576,6 +29720,24 @@ more efficient. Normally in the TCP case, the data is streamed to ClamAV as Exim does not assume that there is a common filesystem with the remote host. There is an option WITH_OLD_CLAMAV_STREAM in &_src/EDITME_& available, should you be running a version of ClamAV prior to 0.95. + +.new +The final example shows that multiple TCP targets can be specified. Exim will +randomly use one for each incoming email (i.e. it load balances them). Note +that only TCP targets may be used if specifying a list of scanners; a UNIX +socket cannot be mixed in with TCP targets. If one of the servers becomes +unavailable, Exim will try the remaining one(s) until it finds one that works. +When a clamd server becomes unreachable, Exim will log a message. Exim does +not keep track of scanner state between multiple messages, and the scanner +selection is random, so the message will get logged in the mainlog for each +email that the down scanner gets chosen first (message wrapped to be readable): +.code +2013-10-09 14:30:39 1VTumd-0000Y8-BQ malware acl condition: + clamd: connection to localhost, port 3310 failed + (Connection refused) +.endd +.wen + If the option is unset, the default is &_/tmp/clamd_&. Thanks to David Saez for contributing the code for this scanner. @@ -31791,9 +31953,11 @@ headers_add = X-added-header: added by $primary_hostname\n\ .endd Exim does not check the syntax of these added header lines. +.new Multiple &%headers_add%& options for a single router or transport can be specified; the values will be concatenated (with a separating newline added) before expansion. +.wen The result of expanding &%headers_remove%& must consist of a colon-separated list of header names. This is confusing, because header names themselves are @@ -33670,7 +33834,9 @@ timestamp. The flags are: &`<=`& message arrival &`=>`& normal message delivery &`->`& additional address in same delivery +.new &`>>`& cutthrough message delivery +.wen &`*>`& delivery suppressed by &%-N%& &`**`& delivery failed; address bounced &`==`& delivery deferred; temporary problem @@ -33770,10 +33936,12 @@ intermediate address(es) exist between the original and the final address, the last of these is given in parentheses after the final address. The R and T fields record the router and transport that were used to process the address. +.new If SMTP AUTH was used for the delivery there is an additional item A= followed by the name of the authenticator that was used. If an authenticated identification was set up by the authenticator's &%client_set_id%& option, this is logged too, separated by a colon from the authenticator name. +.wen If a shadow transport was run after a successful local delivery, the log line for the successful delivery has an item added on the end, of the form @@ -33790,11 +33958,13 @@ flagged with &`->`& instead of &`=>`&. When two or more messages are delivered down a single SMTP connection, an asterisk follows the IP address in the log lines for the second and subsequent messages. +.new .cindex "delivery" "cutthrough; logging" .cindex "cutthrough" "logging" When delivery is done in cutthrough mode it is flagged with &`>>`& and the log line precedes the reception line, since cutthrough waits for a possible rejection from the destination in case it can reject the sourced item. +.wen The generation of a reply message by a filter file gets logged as a &"delivery"& to the addressee, preceded by &">"&. @@ -33972,7 +34142,9 @@ log_selector = +arguments -retry_defer The list of optional log items is in the following table, with the default selection marked by asterisks: .display +.new &` 8bitmime `& received 8BITMIME status +.wen &`*acl_warn_skipped `& skipped &%warn%& statement in ACL &` address_rewrite `& address rewriting &` all_parents `& all parents in => lines @@ -34002,10 +34174,14 @@ selection marked by asterisks: &`*sender_verify_fail `& sender verification failures &`*size_reject `& rejection because too big &`*skip_delivery `& delivery skipped in a queue run +.new &`*smtp_confirmation `& SMTP confirmation on => lines +.wen &` smtp_connection `& SMTP connections &` smtp_incomplete_transaction`& incomplete SMTP transactions +.new &` smtp_mailauth `& AUTH argument to MAIL commands +.wen &` smtp_no_mail `& session with no MAIL commands &` smtp_protocol_error `& SMTP protocol errors &` smtp_syntax_error `& SMTP syntax errors @@ -34021,6 +34197,7 @@ selection marked by asterisks: More details on each of these items follows: .ilist +.new .cindex "8BITMIME" .cindex "log" "8BITMIME" &%8bitmime%&: This causes Exim to log any 8BITMIME status of received messages, @@ -34028,6 +34205,7 @@ which may help in tracking down interoperability issues with ancient MTAs that are not 8bit clean. This is added to the &"<="& line, tagged with &`M8S=`& and a value of &`0`&, &`7`& or &`8`&, corresponding to "not given", &`7BIT`& and &`8BITMIME`& respectively. +.wen .next .cindex "&%warn%& ACL verb" "log when skipping" &%acl_warn_skipped%&: When an ACL &%warn%& statement is skipped because one of @@ -34274,10 +34452,12 @@ the last 20 are listed, preceded by &"..."&. However, with the default setting of 10 for &%smtp_accep_max_nonmail%&, the connection will in any case have been aborted before 20 non-mail commands are processed. .next +.new &%smtp_mailauth%&: A third subfield with the authenticated sender, colon-separated, is appended to the A= item for a message arrival or delivery log line, if an AUTH argument to the SMTP MAIL command (see &<>&) was accepted or used. +.wen .next .cindex "log" "SMTP protocol error" .cindex "SMTP" "logging protocol error" @@ -35681,6 +35861,7 @@ are given in chapter &<>&. +.new .section "Running local commands" "SECTsecconslocalcmds" There are a number of ways in which an administrator can configure Exim to run commands based upon received, untrustworthy, data. Further, in some @@ -35722,6 +35903,7 @@ real-world security vulnerabilities caused by its use with untrustworthy data injected in, for SQL injection attacks. Consider the use of the &%inlisti%& expansion condition instead. .endlist +.wen @@ -36402,7 +36584,7 @@ integer size comparisons against this value. A colon-separated list of names of headers included in the signature. .vitem &%$dkim_key_testing%& "1" if the key record has the "testing" flag set, "0" if not. -.vitem &%$nosubdomains%& +.vitem &%$dkim_key_nosubdomains%& "1" if the key record forbids subdomaining, "0" otherwise. .vitem &%$dkim_key_srvtype%& Service type (tag s=) from the key record. Defaults to "*" if not specified @@ -36479,11 +36661,13 @@ Add to &_src/config.h.defaults_& the line: Edit &_src/drtables.c_&, adding conditional code to pull in the private header and create a table entry as is done for all the other drivers and lookup types. .next +.new Edit &_scripts/lookups-Makefile_& if this is a new lookup; there is a for-loop near the bottom, ranging the &`name_mod`& variable over a list of all lookups. Add your &`NEWDRIVER`& to that list. As long as the dynamic module would be named &_newdriver.so_&, you can use the simple form that most lookups have. +.wen .next Edit &_Makefile_& in the appropriate sub-directory (&_src/routers_&, &_src/transports_&, &_src/auths_&, or &_src/lookups_&); add a line for the new