Set mainlog_name and rejectlog_name unconditionally.

[exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 77784969a5b5e1297c5577209974d98169e10db3..cbb7045a399cc00a77cb74335d2c66c506a858bd 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -228,6 +228,14 @@
   <secondary>failure report</secondary>
   <see><emphasis>bounce message</emphasis></see>
 </indexterm>
   <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>
 <indexterm role="concept">
   <primary>dialup</primary>
   <see><emphasis>intermittently connected hosts</emphasis></see>


@@ -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.
 
 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"
         &~<&'message&~id'&>"
 .oindex "&%-MC%&"
 .cindex "SMTP" "passed connection"


@@ -3919,6 +3929,18 @@ This option is not intended for use by external callers. It is used internally
 by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
 host to which Exim is connected supports TLS encryption.
 
 by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
 host to which Exim is connected supports TLS encryption.
 

+.new
+.vitem &%-MCr%&&~<&'SNI'&> &&&
+       &%-MCs%&&~<&'SNI'&>
+.oindex "&%-MCs%&"
+.oindex "&%-MCr%&"
+These options are not intended for use by external callers. It is used internally
+by Exim in conjunction with the &%-MCt%& option, and passes on the fact that
+a TLS Server Name Indication was sent as part of the channel establishment.
+The argument gives the SNI string.
+The "r" variant indicates a DANE-verified connection.
+.wen
+

 .vitem &%-MCt%&&~<&'IP&~address'&>&~<&'port'&>&~<&'cipher'&>
 .oindex "&%-MCt%&"
 This option is not intended for use by external callers. It is used internally
 .vitem &%-MCt%&&~<&'IP&~address'&>&~<&'port'&>&~<&'cipher'&>
 .oindex "&%-MCt%&"
 This option is not intended for use by external callers. It is used internally


@@ -8735,8 +8757,13 @@ The value for a match will be the list element string.
 .cindex "tainted data" "de-tainting"
 Note that this is commonly untainted
 (depending on the way the list was created).
 .cindex "tainted data" "de-tainting"
 Note that this is commonly untainted
 (depending on the way the list was created).

+Specifically, explicit text in the configuration file in not tainted.

 This is a useful way of obtaining an untainted equivalent to
 the domain, for later operations.
 This is a useful way of obtaining an untainted equivalent to
 the domain, for later operations.

+
+However if the list (including one-element lists)
+is created by expanding a variable containing tainted data,
+it is tainted and so will the match value be.

 .endlist
 
 
 .endlist
 
 


@@ -9455,7 +9482,22 @@ reasons,
 .cindex "tainted data" expansion
 .cindex expansion "tainted data"
 and expansion of data deriving from the sender (&"tainted data"&)
 .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

 
 
 
 
 
 


@@ -12453,17 +12495,23 @@ Often &$domain_data$& is usable in this role.
 
 .vitem &$domain_data$&
 .vindex "&$domain_data$&"
 
 .vitem &$domain_data$&
 .vindex "&$domain_data$&"

-When the &%domains%& option on a router matches a domain by
-means of a lookup, the data read by the lookup is available during the running
-of the router as &$domain_data$&. In addition, if the driver routes the
+When the &%domains%& condition on a router
+.new
+or an ACL
+matches a domain
+against a list, the match value is copied to &$domain_data$&.
+This is an enhancement over previous versions of Exim, when it only
+applied to the data read by a lookup.
+For details on match values see section &<<SECTlistresults>>& et. al.
+.wen
+
+If the router routes the

 address to a transport, the value is available in that transport. If the
 transport is handling multiple addresses, the value from the first address is
 used.
 
 address to a transport, the value is available in that transport. If the
 transport is handling multiple addresses, the value from the first address is
 used.
 

-&$domain_data$& is also set when the &%domains%& condition in an ACL matches a
-domain by means of a lookup. The data read by the lookup is available during
-the rest of the ACL statement. In all other situations, this variable expands
-to nothing.
+&$domain_data$& set in an ACL is available during
+the rest of the ACL statement.

 
 .vitem &$exim_gid$&
 .vindex "&$exim_gid$&"
 
 .vitem &$exim_gid$&
 .vindex "&$exim_gid$&"


@@ -12697,21 +12745,19 @@ to process local parts in a case-dependent manner in a router, you can set the
 
 .vitem &$local_part_data$&
 .vindex "&$local_part_data$&"
 
 .vitem &$local_part_data$&
 .vindex "&$local_part_data$&"

-When the &%local_parts%& option on a router matches a local part by means of a
-lookup, the data read by the lookup is available during the running of the
-router as &$local_part_data$&. In addition, if the driver routes the address
-to a transport, the value is available in that transport. If the transport is
-handling multiple addresses, the value from the first address is used.
+When the &%local_parts%& condition on a router or ACL
+matches a local part list
+.new
+the match value is copied to &$local_part_data$&.
+This is an enhancement over previous versions of Exim, when it only
+applied to the data read by a lookup.
+For details on match values see section &<<SECTlistresults>>& et. al.
+.wen

 
 .new
 The &%check_local_user%& router option also sets this variable.
 .wen
 
 
 .new
 The &%check_local_user%& router option also sets this variable.
 .wen
 

-&$local_part_data$& is also set when the &%local_parts%& condition in an ACL
-matches a local part by means of a lookup. The data read by the lookup is
-available during the rest of the ACL statement. In all other situations, this
-variable expands to nothing.
-

 .vindex &$local_part_prefix$& &&&
        &$local_part_prefix_v$& &&&
        &$local_part_suffix$& &&&
 .vindex &$local_part_prefix$& &&&
        &$local_part_prefix_v$& &&&
        &$local_part_suffix$& &&&


@@ -14387,6 +14433,8 @@ listed in more than one group.
 
 .section "Miscellaneous" "SECID96"
 .table2
 
 .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"
 .row &%bi_command%&                  "to run for &%-bi%& command line option"
 .row &%debug_store%&                 "do extra internal checks"
 .row &%disable_ipv6%&                "do no IPv6 processing"


@@ -14994,6 +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.
 
 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"
 
 .option allow_mx_to_ip main boolean false
 .cindex "MX record" "pointing to IP address"


@@ -16837,7 +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
 .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
 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


@@ -16846,7 +16906,9 @@ When used, the pipelining saves on roundtrip times.
 
 See also the &%hosts_pipe_connect%& smtp transport option.
 
 
 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
 
 
 .option prdr_enable main boolean false


@@ -25383,11 +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"
 .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 &<<SECDANE>>&.
 
 .option hosts_try_fastopen smtp "host list&!!" *
 See section &<<SECDANE>>&.
 
 .option hosts_try_fastopen smtp "host list&!!" *


@@ -25660,7 +25725,11 @@ ciphers is a preference order.
 .option tls_sni smtp string&!! unset
 .cindex "TLS" "Server Name Indication"
 .vindex "&$tls_sni$&"
 .option tls_sni smtp string&!! unset
 .cindex "TLS" "Server Name Indication"
 .vindex "&$tls_sni$&"

-If this option is set then it sets the $tls_out_sni variable and causes any
+If this option is set
+.new
+and the connection is not DANE-validated
+.wen
+then it sets the $tls_out_sni variable and causes any

 TLS session to pass this value as the Server Name Indication extension to
 the remote side, which can be used by the remote side to select an appropriate
 certificate and private key for the session.
 TLS session to pass this value as the Server Name Indication extension to
 the remote side, which can be used by the remote side to select an appropriate
 certificate and private key for the session.


@@ -27614,7 +27683,14 @@ fixed_plain:
   client_send = ^username^mysecret
 .endd
 The lack of colons means that the entire text is sent with the AUTH
   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:
 that uses the LOGIN mechanism is:
 .code
 fixed_login:


@@ -28680,6 +28756,12 @@ Some other recently added features may only be available in one or the other.
 This should be documented with the feature.  If the documentation does not
 explicitly state that the feature is infeasible in the other TLS
 implementation, then patches are welcome.
 This should be documented with the feature.  If the documentation does not
 explicitly state that the feature is infeasible in the other TLS
 implementation, then patches are welcome.

+.new
+.next
+The output from "exim -bV" will show which (if any) support was included
+in the build.
+Also, the macro "_HAVE_OPENSSL" or "_HAVE_GNUTLS" will be defined.
+.wen

 .endlist
 
 
 .endlist
 
 


@@ -29306,6 +29388,11 @@ nothing more to it.  Choosing a sensible value not derived insecurely is 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).
 
 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 DAVE validated the connection attempt then the value of the &%tls_sni%& option
+is forced to the domain part of the recipient address.
+.wen
+

 Except during SMTP client sessions, if &$tls_in_sni$& is set then it is a string
 received from a client.
 It can be logged with the &%log_selector%& item &`+tls_sni`&.
 Except during SMTP client sessions, if &$tls_in_sni$& is set then it is a string
 received from a client.
 It can be logged with the &%log_selector%& item &`+tls_sni`&.


@@ -29509,7 +29596,7 @@ by (a) is thought to be smaller than that of the set of root CAs.
 It also allows the server to declare (implicitly) that connections to it should use TLS.  An MITM could simply
 fail to pass on a server's STARTTLS.
 
 It also allows the server to declare (implicitly) that connections to it should use TLS.  An MITM could simply
 fail to pass on a server's STARTTLS.
 

-DANE scales better than having to maintain (and side-channel communicate) copies of server certificates
+DANE scales better than having to maintain (and communicate via side-channel) copies of server certificates

 for every possible target server.  It also scales (slightly) better than having to maintain on an SMTP
 client a copy of the standard CAs bundle.  It also means not having to pay a CA for certificates.
 
 for every possible target server.  It also scales (slightly) better than having to maintain on an SMTP
 client a copy of the standard CAs bundle.  It also means not having to pay a CA for certificates.
 


@@ -29654,6 +29741,7 @@ If DANE is requested and useable (see above) the following transport options are
   tls_verify_certificates
   tls_crl
   tls_verify_cert_hostnames
   tls_verify_certificates
   tls_crl
   tls_verify_cert_hostnames

+  tls_sni

 .endd
 
 If DANE is not usable, whether requested or not, and CA-anchored
 .endd
 
 If DANE is not usable, whether requested or not, and CA-anchored


@@ -38108,6 +38196,7 @@ selection marked by asterisks:
 &` smtp_protocol_error        `&  SMTP protocol errors
 &` smtp_syntax_error          `&  SMTP syntax errors
 &` subject                    `&  contents of &'Subject:'& on <= lines
 &` 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
 &`*tls_certificate_verified   `&  certificate verification status
 &`*tls_cipher                 `&  TLS cipher suite on <= and => lines
 &` tls_peerdn                 `&  TLS peer DN on <= and => lines


@@ -38501,6 +38590,11 @@ using a CA trust anchor,
 &`CA=dane`& if using a DNS trust anchor,
 and &`CV=no`& if not.
 .next
 &`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
 .cindex "log" "TLS cipher"
 .cindex "TLS" "logging cipher"
 &%tls_cipher%&: When a message is sent or received over an encrypted


@@ -38570,9 +38664,9 @@ the next chapter. The utilities described here are:
   "check address acceptance from given IP"
 .irow &<<SECTdbmbuild>>&      &'exim_dbmbuild'& "build a DBM file"
 .irow &<<SECTfinindret>>&     &'exinext'&       "extract retry information"
   "check address acceptance from given IP"
 .irow &<<SECTdbmbuild>>&      &'exim_dbmbuild'& "build a DBM file"
 .irow &<<SECTfinindret>>&     &'exinext'&       "extract retry information"

-.irow &<<SECThindatmai>>&     &'exim_dumpdb'&   "dump a hints database"
-.irow &<<SECThindatmai>>&     &'exim_tidydb'&   "clean up a hints database"
-.irow &<<SECThindatmai>>&     &'exim_fixdb'&    "patch a hints database"
+.irow &<<SECTdumpdb>>&        &'exim_dumpdb'&   "dump a hints database"
+.irow &<<SECTtidydb>>&        &'exim_tidydb'&   "clean up a hints database"
+.irow &<<SECTfixdb>>&         &'exim_fixdb'&    "patch a hints database"

 .irow &<<SECTmailboxmaint>>&  &'exim_lock'&     "lock a mailbox file"
 .endtable
 
 .irow &<<SECTmailboxmaint>>&  &'exim_lock'&     "lock a mailbox file"
 .endtable
 


@@ -39074,7 +39168,7 @@ in a transport)
 
 
 
 
 
 

-.section "exim_dumpdb" "SECID261"
+.section "exim_dumpdb" "SECTdumpdb"

 .cindex "&'exim_dumpdb'&"
 The entire contents of a database are written to the standard output by the
 &'exim_dumpdb'& program, which has no options or arguments other than the
 .cindex "&'exim_dumpdb'&"
 The entire contents of a database are written to the standard output by the
 &'exim_dumpdb'& program, which has no options or arguments other than the


@@ -39111,7 +39205,7 @@ cross-references.
 
 
 
 
 
 

-.section "exim_tidydb" "SECID262"
+.section "exim_tidydb" "SECTtidydb"

 .cindex "&'exim_tidydb'&"
 The &'exim_tidydb'& utility program is used to tidy up the contents of a hints
 database. If run with no options, it removes all records that are more than 30
 .cindex "&'exim_tidydb'&"
 The &'exim_tidydb'& utility program is used to tidy up the contents of a hints
 database. If run with no options, it removes all records that are more than 30


@@ -39160,7 +39254,7 @@ databases is likely to keep on increasing.
 
 
 
 
 
 

-.section "exim_fixdb" "SECID263"
+.section "exim_fixdb" "SECTfixdb"

 .cindex "&'exim_fixdb'&"
 The &'exim_fixdb'& program is a utility for interactively modifying databases.
 Its main use is for testing Exim, but it might also be occasionally useful for
 .cindex "&'exim_fixdb'&"
 The &'exim_fixdb'& program is a utility for interactively modifying databases.
 Its main use is for testing Exim, but it might also be occasionally useful for