X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/062b77ca80a10aba99d2cf09d4a8600ca3385e24..41c494e2465efadc2e82002a07430e8aec85bc9b:/doc/doc-docbook/spec.xfpt?ds=inline diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 4f411a503..cbb7045a3 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -228,6 +228,14 @@ failure report bounce message + + de-tainting + tainting, de-tainting + + + detainting + tainting, de-tainting + dialup intermittently connected hosts @@ -3847,7 +3855,9 @@ id, and the remaining ones must be email addresses. However, if the message is active (in the middle of a delivery attempt), it is not altered. This option can be used only by an admin user. -.vitem "&%-MC%&&~<&'transport'&>&~<&'hostname'&>&~<&'sequence&~number'&>&&& +.vitem "&%-MC%&&~<&'transport'&>&~<&'hostname'&>&&& + &~<&'host&~IP'&>&&& + &~<&'sequence&~number'&>&&& &~<&'message&~id'&>" .oindex "&%-MC%&" .cindex "SMTP" "passed connection" @@ -9472,7 +9482,22 @@ reasons, .cindex "tainted data" expansion .cindex expansion "tainted data" and expansion of data deriving from the sender (&"tainted data"&) -is not permitted. +.new +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. +.wen + +.new +Common ways of obtaining untainted equivalents of variables with +tainted values +.cindex "tainted data" "de-tainting" +come down to using the tainted value as a lookup key in a trusted database. +This database could be the filesystem structure, +or the password file, +or accessed via a DBMS. +Specific methods are indexed under &"de-tainting"&. +.wen @@ -14408,6 +14433,8 @@ listed in more than one group. .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" @@ -15015,6 +15042,18 @@ domains (defined in the named domain list &%local_domains%& in the default configuration). This &"magic string"& matches the domain literal form of all the local host's IP addresses. +.new +.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. +.wen + + .option allow_mx_to_ip main boolean false .cindex "MX record" "pointing to IP address" @@ -16858,7 +16897,7 @@ not count as protocol errors (see &%smtp_max_synprot_errors%&). .option pipelining_connect_advertise_hosts main "host list&!!" * .cindex "pipelining" "early connection" .cindex "pipelining" PIPE_CONNECT -.cindex "ESMTP extensions" X_PIPE_CONNECT +.cindex "ESMTP extensions" PIPE_CONNECT If Exim is built with the SUPPORT_PIPE_CONNECT build option this option controls which hosts the facility is advertised to and from which pipeline early-connection (before MAIL) SMTP @@ -16867,7 +16906,9 @@ When used, the pipelining saves on roundtrip times. See also the &%hosts_pipe_connect%& smtp transport option. -Currently the option name &"X_PIPE_CONNECT"& is used. +.new +The SMTP service extension keyword advertised is &"PIPE_CONNECT"&. +.wen .option prdr_enable main boolean false @@ -25404,11 +25445,14 @@ BDAT will not be used in conjunction with a transport filter. .option hosts_try_dane smtp "host list&!!" * .cindex DANE "transport options" .cindex DANE "attempting for certain servers" -If built with DANE support, Exim will require that a DNSSEC-validated -TLSA record is present for any host matching the list, -and that a DANE-verified TLS connection is made. See -the &%dnssec_request_domains%& router and transport options. -There will be no fallback to in-clear communication. +.new +If built with DANE support, Exim will look up a +TLSA record for any host matching the list, +If one is found and that lookup was DNSSEC-validated, +then Exim requires that a DANE-verified TLS connection is made for that host; +there will be no fallback to in-clear communication. +.wen +See the &%dnssec_request_domains%& router and transport options. See section &<>&. .option hosts_try_fastopen smtp "host list&!!" * @@ -27639,7 +27683,14 @@ fixed_plain: client_send = ^username^mysecret .endd The lack of colons means that the entire text is sent with the AUTH -command, with the circumflex characters converted to NULs. A similar example +command, with the circumflex characters converted to NULs. +.new +Note that due to the ambiguity of parsing three consectutive circumflex characters +there is no way to provide a password having a leading circumflex. +.wen + + +A similar example that uses the LOGIN mechanism is: .code fixed_login: @@ -38145,6 +38196,7 @@ selection marked by asterisks: &` 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 @@ -38538,6 +38590,11 @@ using a CA trust anchor, &`CA=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