X-Git-Url: https://git.exim.org/users/heiko/exim.git/blobdiff_plain/c0635b6dfe65ee24c2fb8d165beabc608d2fd1a5..f3908561b1eef15d57608ab6b346125bf2a11478:/doc/doc-docbook/spec.xfpt diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index bb7e2cf97..7d5b3b3cf 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -52,7 +52,7 @@ .set I "    " .macro copyyear -2017 +2018 .endmacro . ///////////////////////////////////////////////////////////////////////////// @@ -7839,6 +7839,19 @@ ${lookup redis{set keyname ${quote_redis:objvalue plus}}} ${lookup redis{get keyname}} .endd +.new +As of release 4.91, "lightweight" support for Redis Cluster is available. +Requires &%redis_servers%& list to contain all the servers in the cluster, all +of which must be reachable from the running exim instance. If the cluster has +master/slave replication, the list must contain all the master and slave +servers. + +When the Redis Cluster returns a "MOVED" response to a query, exim does not +immediately follow the redirection but treats the response as a DEFER, moving on +to the next server in the &%redis_servers%& list until the correct server is +reached. +.wen + .ecindex IIDfidalo1 .ecindex IIDfidalo2 @@ -9137,6 +9150,33 @@ the expansion result is an empty string. If the ACL returns defer the result is a forced-fail. Otherwise the expansion fails. +.new +.vitem "&*${authresults{*&<&'authserv-id'&>&*}}*&" +.cindex authentication "results header" +.cindex headers "authentication-results:" +.cindex authentication "expansion item" +This item returns a string suitable for insertion as an +&'Authentication-Results"'& +header line. +The given <&'authserv-id'&> is included in the result; typically this +will ba a domain name identifying the system performing the authentications. +Methods that may be present in the result include: +.code +none +iprev +auth +spf +dkim +.endd + +Example use (as an ACL modifier): +.code + add_header = :at_start:${authresults {$primary_hostname}} +.endd +This is safe even if no authentication reselts are available. +.wen + + .vitem "&*${certextract{*&<&'field'&>&*}{*&<&'certificate'&>&*}&&& {*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&" .cindex "expansion" "extracting certificate fields" @@ -11898,6 +11938,13 @@ lookup succeeds, but there is a lookup problem such as a timeout when checking the result, the name is not accepted, and &$host_lookup_deferred$& is set to &"1"&. See also &$sender_host_name$&. +.new +.cindex authentication "expansion item" +Performing these checks sets up information used by the +&$authresults$& expansion item. +.wen + + .vitem &$host_lookup_failed$& .vindex "&$host_lookup_failed$&" See &$host_lookup_deferred$&. @@ -12853,6 +12900,7 @@ is compiled with the content-scanning extension. For details, see section .vitem &$spf_header_comment$& &&& &$spf_received$& &&& &$spf_result$& &&& + &$spf_result_guessed$& &&& &$spf_smtp_comment$& These variables are only available if Exim is built with SPF support. For details see section &<>&. @@ -26066,6 +26114,12 @@ public name) of the authenticator driver that successfully authenticated the client from which the message was received. This variable is empty if there was no successful authentication. +.new +.cindex authentication "expansion item" +Successful authentication sets up information used by the +&$authresults$& expansion item. +.wen + @@ -28128,7 +28182,16 @@ If verification was successful using DANE then the "CV" item in the delivery log There is a new variable &$tls_out_dane$& which will have "yes" if verification succeeded using DANE and "no" otherwise (only useful -in combination with EXPERIMENTAL_EVENT), and a new variable &$tls_out_tlsa_usage$& (detailed above). +in combination with events; see &<>&), +and a new variable &$tls_out_tlsa_usage$& (detailed above). + +.cindex DANE reporting +An event (see &<>&) of type "dane:fail" will be raised on failures +to achieve DANE-verified connection, if one was either requested and offered, or +required. This is intended to support TLS-reporting as defined in +&url(https://tools.ietf.org/html/draft-ietf-uta-smtp-tlsrpt-17). +The &$event_data$& will be one of the Result Types defined in +Section 4.3 of that document. Under GnuTLS, DANE is only supported from version 3.0.0 onwards. .wen @@ -31772,9 +31835,9 @@ though individual ones can be included or not at build time: .vitem &%avast%& .cindex "virus scanners" "avast" This is the scanner daemon of Avast. It has been tested with Avast Core -Security (currently at version 1.1.7). -You can get a trial version at &url(http://www.avast.com) or for Linux -at &url(http://www.avast.com/linux-server-antivirus). +Security (currently at version 2.2.0). +You can get a trial version at &url(https://www.avast.com) or for Linux +at &url(https://www.avast.com/linux-server-antivirus). This scanner type takes one option, which can be either a full path to a UNIX socket, or host and port specifiers separated by white space. @@ -31801,6 +31864,8 @@ $ socat UNIX:/var/run/avast/scan.sock STDIO: PACK .endd +Only the first virus detected will be reported. + .vitem &%aveserver%& .cindex "virus scanners" "Kaspersky" @@ -38854,7 +38919,8 @@ The result can either be a valid RSA private key in ASCII armor (.pem file), including line breaks .new .next -with GnuTLS 3.6.0 or later, be a valid Ed25519 private key (same format as above) +with GnuTLS 3.6.0 or OpenSSL 1.1.1 or later, +be a valid Ed25519 private key (same format as above) .wen .next start with a slash, in which case it is treated as a file that contains @@ -38866,6 +38932,20 @@ is set. .endlist .new +To generate keys under OpenSSL: +.code +openssl genrsa -out dkim_rsa.private 2048 +openssl rsa -in dkim_rsa.private -out /dev/stdout -pubout -outform PEM +.endd +Take the base-64 lines from the output of the second command, concatenated, +for the DNS TXT record. + +Under GnuTLS: +.code +certtool --generate-privkey --rsa --bits=2048 --password='' -8 --outfile=dkim_rsa.private +certtool --load-privkey=dkim_rsa.private --pubkey-info +.endd + Note that RFC 8301 says: .code Signers MUST use RSA keys of at least 1024 bits for all keys. @@ -38880,6 +38960,21 @@ As they are a recent development, users should consider dual-signing for some transition period. The "_CRYPTO_SIGN_ED25519" macro will be defined if support is present for EC keys. + +As of writing, producing EC key materials is not well supported +by the major libraries. OpenSSL 1.1.1 and GnuTLS 3.6.0 can create private keys: +.code +openssl genpkey -algorithm ed25519 -out dkim_ed25519.private +certtool --generate-privkey --key-type=ed25519 --outfile=dkim_ed25519.private +.endd + +To help in producing the required public key value for a DNS record +the release package &_util/_& directory contains source for a utility +buildable with GnuTLS 3.6.0; +use it like this: +.code +ed25519_privkey_pem_to_pubkey_raw_b64 dkim_ed25519.private +.endd .wen .option dkim_hash smtp string&!! sha256 @@ -38950,6 +39045,12 @@ To evaluate the signature in the ACL a large number of expansion variables containing the signature status and its details are set up during the runtime of the ACL. +.new +.cindex authentication "expansion item" +Performing verification sets up information used by the +&$authresults$& expansion item. +.wen + Calling the ACL only for existing signatures is not sufficient to build more advanced policies. For that reason, the global option &%dkim_verify_signers%&, and a global expansion variable @@ -39015,11 +39116,13 @@ This variable can be overwritten using an ACL 'set' modifier. This might, for instance, be done to enforce a policy restriction on hash-method or key-size: .code - warn condition = ${if eq {$dkim_algo}{rsa-sha1}} - condition = ${if eq {$dkim_verify_status}{pass}} + warn condition = ${if eq {$dkim_verify_status}{pass}} + condition = ${if eq {$len_3:$dkim_algo}{rsa}} + condition = ${if or {eq {$dkim_algo}{rsa-sha1}} \ + {< {$dkim_key_length}{1024}} } logwrite = NOTE: forcing dkim verify fail (was pass) set dkim_verify_status = fail - set dkim_verify_reason = hash too weak + set dkim_verify_reason = hash too weak or key too short .endd After all the DKIM ACL runs have completed, the value becomes a @@ -39063,7 +39166,8 @@ The key record selector string. .vitem &%$dkim_algo%& The algorithm used. One of 'rsa-sha1' or 'rsa-sha256'. .new -If running under GnuTLS 3.6.0 or later, may also be 'ed25519-sha256'. +If running under GnuTLS 3.6.0 or OpenSSL 1.1.1 or later, +may also be 'ed25519-sha256'. The "_CRYPTO_SIGN_ED25519" macro will be defined if support is present for EC keys. .wen @@ -39108,6 +39212,9 @@ UNIX timestamp reflecting the date and time when the signer wants the signature to be treated as "expired". When this was not specified by the signer, "9999999999999" is returned. This makes it possible to do useful integer size comparisons against this value. +.new +Note that Exim does not check this value. +.wen .vitem &%$dkim_headernames%& A colon-separated list of names of headers included in the signature. @@ -39141,6 +39248,7 @@ less than 1024 bits as valid signatures. To enforce this you must have a DKIM ACL which checks this variable and overwrites the &$dkim_verify_status$& variable as discussed above. +As EC keys are much smaller, the check should only do this for RSA keys. .wen .endlist @@ -39203,6 +39311,12 @@ There is no Exim involvement on the trasmission of messages; publishing certain DNS records is all that is required. For verification, an ACL condition and an expansion lookup are provided. +.new +.cindex authentication "expansion item" +Performing verification sets up information used by the +&$authresults$& expansion item. +.wen + .cindex SPF "ACL condition" .cindex ACL "spf condition" @@ -39291,6 +39405,11 @@ variables: one of pass, fail, softfail, none, neutral, permerror or temperror. +.vitem &$spf_result_guessed$& +.vindex &$spf_result_guessed$& + This boolean is true only if a best-guess operation was used + and required in order to obtain a result. + .vitem &$spf_smtp_comment$& .vindex &$spf_smtp_comment$& This contains a string that can be used in a SMTP response @@ -39678,6 +39797,7 @@ expansion must check this, as it will be called for every possible event type. The current list of events is: .display +&`dane:fail after transport `& per connection &`msg:complete after main `& per message &`msg:delivery after transport `& per recipient &`msg:rcpt:host:defer after transport `& per recipient per host @@ -39706,6 +39826,7 @@ should define the event action. An additional variable, &$event_data$&, is filled with information varying with the event type: .display +&`dane:fail `& failure reason &`msg:delivery `& smtp confirmation message &`msg:rcpt:host:defer `& error string &`msg:rcpt:defer `& error string @@ -39733,15 +39854,12 @@ The expansion of the event_action option should normally return an empty string. Should it return anything else the following will be forced: .display -&`msg:delivery `& (ignored) -&`msg:host:defer `& (ignored) -&`msg:fail:delivery`& (ignored) &`tcp:connect `& do not connect -&`tcp:close `& (ignored) &`tls:cert `& refuse verification &`smtp:connect `& close connection .endd -No other use is made of the result string. +All other message types ignore the result string, and +no other use is made of it. For a tcp:connect event, if the connection is being made to a proxy then the address and port variables will be that of the proxy and not