X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/ffc92d69bf2618aca35f2c523abde0a76657e3a2..fea4bca6d58bf154207c7670236eab751e22f766:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 46cab7c58..856bb0c15 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -2766,6 +2766,8 @@ used to specify a path on the command line if a pid file is required. The SIGHUP signal .cindex "SIGHUP" .cindex "daemon" "restarting" +.cindex signal "to reload configuration" +.cindex daemon "reload configuration" can be used to cause the daemon to re-execute itself. This should be done whenever Exim's configuration file, or any file that is incorporated into it by means of the &%.include%& facility, is changed, and also whenever a new version @@ -6741,6 +6743,12 @@ lookup types support only literal keys. &*Warning 2*&: In a host list, you must always use &(net-iplsearch)& so that the implicit key is the host's IP address rather than its name (see section &<>&). + +.new +&*Warning 3*&: Do not use an IPv4-mapped IPv6 address for a key; use the +IPv4, in dotted-quad form. (Exim converts IPv4-mapped IPv6 addresses to this +notation before executing the lookup.) +.wen .next .new .cindex lookup json @@ -6755,9 +6763,10 @@ of the JSON structure. If a selector is numeric, it must apply to a JSON array; the (zero-based) nunbered array element is selected. Otherwise it must apply to a JSON object; the named element is selected. -The final resulting object can be a simple JSOM type or a JSON object +The final resulting element can be a simple JSON type or a JSON object or array; for the latter two a string-representation os the JSON is returned. +For elements of type string, the returned value is de-quoted. .wen .next .cindex "linear search" @@ -8677,8 +8686,12 @@ to quote keys was made available in &(lsearch)& files. However, the more recently implemented &(iplsearch)& files do require colons in IPv6 keys (notated using the quoting facility) so as to distinguish them from IPv4 keys. For this reason, when the lookup type is &(iplsearch)&, IPv6 addresses are -converted using colons and not dots. In all cases, full, unabbreviated IPv6 +converted using colons and not dots. +.new +In all cases except IPv4-mapped IPv6, full, unabbreviated IPv6 addresses are always used. +The latter are converted to IPv4 addresses, in dotted-quad form. +.wen Ideally, it would be nice to tidy up this anomalous situation by changing to colons in all cases, given that quoting is now available for &(lsearch)&. @@ -9187,6 +9200,7 @@ Many strings in Exim's runtime configuration are expanded before use. Some of them are expanded every time they are used; others are expanded only once. When a string is being expanded it is copied verbatim from left to right except +.cindex expansion "string concatenation" when a dollar or backslash character is encountered. A dollar specifies the start of a portion of the string that is interpreted and replaced as described below in section &<>& onwards. Backslash is used as an @@ -9536,6 +9550,8 @@ This forces an expansion failure (see section &<>&); {<&'string2'&>} must be present for &"fail"& to be recognized. .vitem "&*${extract json{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}&&& + {*&<&'string3'&>&*}}*&" &&& + "&*${extract jsons{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}&&& {*&<&'string3'&>&*}}*&" .cindex "expansion" "extracting from JSON object" .cindex JSON expansions @@ -9550,6 +9566,13 @@ The expanded <&'string1'&> must be of the form: The braces, commas and colons, and the quoting of the member name are required; the spaces are optional. Matching of the key against the member names is done case-sensitively. +For the &"json"& variant, +if a returned value is a JSON string, it retains its leading and +trailing quotes. +.new +For the &"jsons"& variant, which is intended for use with JSON strings, the +leading and trailing quotes are removed from the returned value. +.wen . XXX should be a UTF-8 compare The results of matching are handled as above. @@ -9586,7 +9609,9 @@ yields &"99"&. Two successive separators mean that the field between them is empty (for example, the fifth field above). -.vitem "&*${extract json{*&<&'number'&>&*}}&&& +.vitem "&*${extract json {*&<&'number'&>&*}}&&& + {*&<&'string1'&>&*}{*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&" &&& + "&*${extract jsons{*&<&'number'&>&*}}&&& {*&<&'string1'&>&*}{*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&" .cindex "expansion" "extracting from JSON array" .cindex JSON expansions @@ -9595,6 +9620,13 @@ apart from leading and trailing white space, which is ignored. Field selection and result handling is as above; there is no choice of field separator. +For the &"json"& variant, +if a returned value is a JSON string, it retains its leading and +trailing quotes. +.new +For the &"jsons"& variant, which is intended for use with JSON strings, the +leading and trailing quotes are removed from the returned value. +.wen .vitem &*${filter{*&<&'string'&>&*}{*&<&'condition'&>&*}}*& @@ -10925,11 +10957,15 @@ If the string is a single variable of type certificate, returns the SHA-1 hash fingerprint of the certificate. -.vitem &*${sha256:*&<&'string'&>&*}*& +.vitem &*${sha256:*&<&'string'&>&*}*& &&& + &*${sha2:*&<&'string'&>&*}*& &&& + &*${sha2_:*&<&'string'&>&*}*& .cindex "SHA-256 hash" +.cindex "SHA-2 hash" .cindex certificate fingerprint .cindex "expansion" "SHA-256 hashing" .cindex "&%sha256%& expansion item" +.cindex "&%sha2%& expansion item" The &%sha256%& operator computes the SHA-256 hash value of the string and returns it as a 64-digit hexadecimal number, in which any letters are in upper case. @@ -10937,6 +10973,15 @@ it as a 64-digit hexadecimal number, in which any letters are in upper case. If the string is a single variable of type certificate, returns the SHA-256 hash fingerprint of the certificate. +.new +The operator can also be spelled &%sha2%& and does the same as &%sha256%& +(except for certificates, which are not supported). +Finally, if an underbar +and a number is appended it specifies the output length, selecting a +member of the SHA-2 family of hash functions. +Values of 256, 384 and 512 are accepted, with 256 being the default. +.wen + .vitem &*${sha3:*&<&'string'&>&*}*& &&& &*${sha3_:*&<&'string'&>&*}*& @@ -11322,6 +11367,25 @@ being processed, to enable these expansion items to be nested. To scan a named list, expand it with the &*listnamed*& operator. +.new +.vitem "&*forall_json{*&<&'a JSON array'&>&*}{*&<&'a condition'&>&*}*&" &&& + "&*forany_json{*&<&'a JSON array'&>&*}{*&<&'a condition'&>&*}*&" &&& + "&*forall_jsons{*&<&'a JSON array'&>&*}{*&<&'a condition'&>&*}*&" &&& + "&*forany_jsons{*&<&'a JSON array'&>&*}{*&<&'a condition'&>&*}*&" +.cindex JSON "iterative conditions" +.cindex JSON expansions +.cindex expansion "&*forall_json*& condition" +.cindex expansion "&*forany_json*& condition" +.cindex expansion "&*forall_jsons*& condition" +.cindex expansion "&*forany_jsons*& condition" +As for the above, except that the first argument must, after expansion, +be a JSON array. +The array separator is not changeable. +For the &"jsons"& variants the elements are expected to be JSON strings +and have their quotes removed before the evaluation of the condition. +.wen + + .vitem &*ge&~{*&<&'string1'&>&*}{*&<&'string2'&>&*}*& &&& &*gei&~{*&<&'string1'&>&*}{*&<&'string2'&>&*}*& @@ -12132,6 +12196,7 @@ This variable contains the version string of the Exim build. The first character is a major version number, currently 4. Then after a dot, the next group of digits is a minor version number. There may be other characters following the minor version. +This value may be overridden by the &%exim_version%& main config option. .vitem &$header_$&<&'name'&> This is not strictly an expansion variable. It is expansion syntax for @@ -13309,6 +13374,12 @@ The deprecated &$tls_cipher$& variable is the same as &$tls_in_cipher$& during m but in the context of an outward SMTP delivery taking place via the &(smtp)& transport becomes the same as &$tls_out_cipher$&. +.new +.vitem &$tls_in_cipher_std$& +.vindex "&$tls_in_cipher_std$&" +As above, but returning the RFC standard name for the cipher suite. +.wen + .vitem &$tls_out_cipher$& .vindex "&$tls_out_cipher$&" This variable is @@ -13317,6 +13388,12 @@ and then set to the outgoing cipher suite if one is negotiated. See chapter &<>& for details of TLS support and chapter &<>& for details of the &(smtp)& transport. +,new +.vitem &$tls_out_cipher_std$& +.vindex "&$tls_out_cipher_std$&" +As above, but returning the RFC standard name for the cipher suite. +.wen + .vitem &$tls_out_dane$& .vindex &$tls_out_dane$& DANE active status. See section &<>&. @@ -13451,7 +13528,8 @@ Otherwise, empty. .vitem &$version_number$& .vindex "&$version_number$&" -The version number of Exim. +The version number of Exim. Same as &$exim_version$&, may be overridden +by the &%exim_version%& main config option. .vitem &$warn_message_delay$& .vindex "&$warn_message_delay$&" @@ -15282,6 +15360,14 @@ not also supplied, the gid is taken from the result of &[getpwnam()]& if it is used. See chapter &<>& for a discussion of security issues. +.option exim_version main string "current version" +.cindex "Exim version" +.cindex customizing "version number" +.cindex "version number of Exim" override +This option allows to override the &$version_number$&/&$exim_version$& Exim reports in +various places. Use with care, this may fool stupid security scanners. + + .option extra_local_interfaces main "string list" unset This option defines network interfaces that are to be considered local when routing, but which are not used for listening by the daemon. See section @@ -16107,7 +16193,7 @@ harm. This option overrides the &%pipe_as_creator%& option of the &(pipe)& transport driver. -.option openssl_options main "string list" "+no_sslv2 +single_dh_use +no_ticket" +.option openssl_options main "string list" "+no_sslv2 +no_sslv3 +single_dh_use +no_ticket" .cindex "OpenSSL "compatibility options" This option allows an administrator to adjust the SSL options applied by OpenSSL to connections. It is given as a space-separated list of items, @@ -16547,23 +16633,26 @@ on at the end (preceded by a semicolon). The string is expanded each time it is used. If the expansion yields an empty string, no &'Received:'& header line is added to the message. Otherwise, the string should start with the text &"Received:"& and conform to the RFC 2822 specification for &'Received:'& -header lines. The default setting is: +header lines. +.new +The default setting is: .code received_header_text = Received: \ ${if def:sender_rcvhost {from $sender_rcvhost\n\t}\ - {${if def:sender_ident \ - {from ${quote_local_part:$sender_ident} }}\ - ${if def:sender_helo_name {(helo=$sender_helo_name)\n\t}}}}\ + {${if def:sender_ident \ + {from ${quote_local_part:$sender_ident} }}\ + ${if def:sender_helo_name {(helo=$sender_helo_name)\n\t}}}}\ by $primary_hostname \ - ${if def:received_protocol {with $received_protocol}} \ - ${if def:tls_in_cipher {($tls_in_cipher)\n\t}}\ + ${if def:received_protocol {with $received_protocol }}\ + ${if def:tls_in_cipher_std { tls $tls_in_cipher_std\n\t}}\ (Exim $version_number)\n\t\ ${if def:sender_address \ {(envelope-from <$sender_address>)\n\t}}\ id $message_exim_id\ ${if def:received_for {\n\tfor $received_for}} .endd +.wen The reference to the TLS cipher is omitted when Exim is built without TLS support. The use of conditional expansions ensures that this works for both @@ -17500,7 +17589,7 @@ use when sending messages as a client, you must set the &%tls_certificate%& option in the relevant &(smtp)& transport. &*Note*&: If you use filenames based on IP addresses, change the list -separator in the usual way (&<>&) >to avoid confusion under IPv6. +separator in the usual way (&<>&) to avoid confusion under IPv6. &*Note*&: Under versions of OpenSSL preceding 1.1.1, when a list of more than one @@ -24503,13 +24592,15 @@ been started will not be passed to a new delivery process for sending another message on the same connection. See section &<>& for an explanation of when this might be needed. -.option hosts_noproxy_tls smtp "host list&!!" * +.new +.option hosts_noproxy_tls smtp "host list&!!" unset .cindex "TLS" "passing connection" .cindex "multiple SMTP deliveries" .cindex "TLS" "multiple message deliveries" For any host that matches this list, a TLS session which has been started will not be passed to a new delivery process for sending another message on the same session. +.wen The traditional implementation closes down TLS and re-starts it in the new process, on the same open TCP connection, for each successive message @@ -24605,7 +24696,7 @@ This option provides a list of servers to which, provided they announce CHUNKING support, Exim will attempt to use BDAT commands rather than DATA. BDAT will not be used in conjunction with a transport filter. -.option hosts_try_dane smtp "host list&!!" unset +.option hosts_try_dane smtp "host list&!!" * .cindex DANE "transport options" .cindex DANE "attempting for certain servers" If built with DANE support, Exim will lookup a @@ -27438,7 +27529,7 @@ but is a full SMTP SASL authenticator rather than being implicit for TLS-connection carried client certificates only. -The examples and discussion in this chapter assume that +The examples and discussion in this chapter assume that client-certificate authentication is being done. The client must present a certificate, @@ -28254,7 +28345,7 @@ There is no current way to staple a proof for a client certificate. -.section "Configuring an Exim client to use TLS" "SECID185" +.section "Configuring an Exim client to use TLS" "SECTclientTLS" .cindex "cipher" "logging" .cindex "log" "TLS cipher" .cindex "log" "distinguished name" @@ -30779,7 +30870,7 @@ For SMTP input that does not come over TCP/IP (the &%-bs%& command line option), this condition is always true. -.vitem &*verify&~=&~not_blind*& +.vitem &*verify&~=&~not_blind/*&<&'options'&> .cindex "verifying" "not blind" .cindex "bcc recipients, verifying none" This condition checks that there are no blind (bcc) recipients in the message. @@ -30789,6 +30880,11 @@ case-sensitively; domains are checked case-insensitively. If &'Resent-To:'& or &'Resent-Cc:'& header lines exist, they are also checked. This condition can be used only in a DATA or non-SMTP ACL. +.new +There is one possible option, &`case_insensitive`&. If this is present then +local parts are checked case-insensitively. +.wen + There are, of course, many legitimate messages that make use of blind (bcc) recipients. This check should not be used on its own for blocking messages. @@ -36948,7 +37044,7 @@ the following table: &`F `& sender address (on delivery lines) &`H `& host name and IP address &`I `& local interface used -&`id `& message id for incoming message +&`id `& message id (from header) for incoming message &`K `& CHUNKING extension used &`L `& on &`<=`& and &`=>`& lines: PIPELINING extension used &`M8S `& 8BITMIME status for incoming message @@ -37055,6 +37151,8 @@ selection marked by asterisks: &` 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 @@ -37238,6 +37336,16 @@ connection is unexpectedly dropped. &%millisec%&: Timestamps have a period and three decimal places of finer granularity appended to the seconds value. .next +.new +.cindex "log" "message id" +&%msg_id%&: The value of the Message-ID: header. +.next +&%msg_id_created%&: The value of the Message-ID: header, when one had to be created. +This will be either because the message is a bounce, or was submitted locally +(submission mode) without one. +The field identifier will have an asterix appended: &"id*="&. +.wen +.next .cindex "log" "outgoing interface" .cindex "log" "local interface" .cindex "log" "local address and port" @@ -37627,6 +37735,11 @@ Match only frozen messages. .vitem &*-x*& Match only non-frozen messages. + +.new +.vitem &*-G*&&~<&'queuename'&> +Match only messages in the given queue. Without this, the default queue is searched. +.wen .endlist The following options control the format of the output: @@ -39481,7 +39594,7 @@ senders). .cindex "DKIM" "signing" For signing to be usable you must have published a DKIM record in DNS. -Note that RFC 8301 says: +Note that RFC 8301 (which does not cover EC keys) says: .code rsa-sha1 MUST NOT be used for signing or verifying. @@ -39501,7 +39614,11 @@ These options take (expandable) strings as arguments. .option dkim_domain smtp string list&!! unset The domain(s) you want to sign with. After expansion, this can be a list. -Each element in turn is put into the &%$dkim_domain%& expansion variable +Each element in turn, +.new +lowercased, +.wen +is put into the &%$dkim_domain%& expansion variable while expanding the remaining signing options. If it is empty after expansion, DKIM signing is not done, and no error will result even if &%dkim_strict%& is set. @@ -39555,8 +39672,9 @@ Signers MUST use RSA keys of at least 1024 bits for all keys. Signers SHOULD use RSA keys of at least 2048 bits. .endd -Support for EC keys is being developed under -&url(https://datatracker.ietf.org/doc/draft-ietf-dcrup-dkim-crypto/). +.new +EC keys for DKIM are defined by RFC 8463. +.wen They are considerably smaller than RSA keys for equivalent protection. As they are a recent development, users should consider dual-signing (by setting a list of selectors, and an expansion for this option) @@ -39576,10 +39694,12 @@ openssl pkey -outform DER -pubout -in dkim_ed25519.private | tail -c +13 | base6 certtool --load_privkey=dkim_ed25519.private --pubkey_info --outder | tail -c +13 | base64 .endd -Note that the format -of Ed25519 keys in DNS has not yet been decided; this release supports -both of the leading candidates at this time, a future release will -probably drop support for whichever proposal loses. +.new +Exim also supports an alternate format +of Ed25519 keys in DNS which was a candidate during development +of the standard, but not adopted. +A future release will probably drop that support. +.wen .option dkim_hash smtp string&!! sha256 Can be set to any one of the supported hash methods, which are: @@ -39702,6 +39822,14 @@ dkim_verify_signers = $sender_address_domain:$dkim_signers If a domain or identity is listed several times in the (expanded) value of &%dkim_verify_signers%&, the ACL is only called once for that domain or identity. +.new +Note that if the option is set using untrustworthy data +(such as the From: header) +care should be taken to force lowercase for domains +and for the domain part if identities. +The default setting can be regarded as trustworthy in this respect. +.wen + If multiple signatures match a domain (or identity), the ACL is called once for each matching signature. @@ -40139,6 +40267,8 @@ of the proxy): .endd If &$proxy_session$& is set but &$proxy_external_address$& is empty there was a protocol error. +The variables &$sender_host_address$& and &$sender_host_port$& +will have values for the actual client system, not the proxy. Since the real connections are all coming from the proxy, and the per host connection tracking is done before Proxy Protocol is