Debug: more detail in dkim processing

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

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 16cd394ac854510dad3cfd1a5c791a6cad8890eb..2c783d700ed5982bf8541a0f22d9af78517594b1 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -3162,6 +3162,10 @@ If invoked by an admin user, then &%macro%&, &%macro_list%& and &%macros%&
 are available, similarly to the drivers.  Because macros are sometimes used
 for storing passwords, this option is restricted.
 The output format is one item per line.
 are available, similarly to the drivers.  Because macros are sometimes used
 for storing passwords, this option is restricted.
 The output format is one item per line.

+.new
+For the "-bP macro <name>" form, if no such macro is found
+the exit status will be nonzero.
+.wen

 
 .vitem &%-bp%&
 .oindex "&%-bp%&"
 
 .vitem &%-bp%&
 .oindex "&%-bp%&"


@@ -10648,6 +10652,7 @@ The &%sha3%& expansion item is only supported if Exim has been
 compiled with GnuTLS 3.5.0 or later,
 .new
 or OpenSSL 1.1.1 or later.
 compiled with GnuTLS 3.5.0 or later,
 .new
 or OpenSSL 1.1.1 or later.

+The macro "_CRYPTO_HASH_SHA3" will be defined if it is supported.

 .wen
 
 
 .wen
 
 


@@ -11670,7 +11675,7 @@ contain the trailing slash. If &$config_file$& does not contain a slash,
 .vindex "&$config_file$&"
 The name of the main configuration file Exim is using.
 
 .vindex "&$config_file$&"
 The name of the main configuration file Exim is using.
 

-.vitem &$dkim_verify_status$& &&&
+.vitem &$dkim_verify_status$&

 Results of DKIM verification.
 For details see section &<<SECDKIMVFY>>&.
 
 Results of DKIM verification.
 For details see section &<<SECDKIMVFY>>&.
 


@@ -16919,8 +16924,8 @@ and any external programs which are passed a reference to a message data file
 will need to be aware of the potential different format.
 
 Using any of the ACL conditions noted will negate the reception benefit
 will need to be aware of the potential different format.
 
 Using any of the ACL conditions noted will negate the reception benefit

-(as a Unix-mbox-format file is contructed for them).
-The transimssion benefit is maintained.
+(as a Unix-mbox-format file is constructed for them).
+The transmission benefit is maintained.

 
 .option sqlite_lock_timeout main time 5s
 .cindex "sqlite lookup type" "lock timeout"
 
 .option sqlite_lock_timeout main time 5s
 .cindex "sqlite lookup type" "lock timeout"


@@ -17147,7 +17152,7 @@ option in the relevant &(smtp)& transport.
 separator in the usual way to avoid confusion under IPv6.
 
 &*Note*&: Under current versions of OpenSSL, when a list of more than one
 separator in the usual way to avoid confusion under IPv6.
 
 &*Note*&: Under current versions of OpenSSL, when a list of more than one

-file is used, the &$tls_in_ourcert$& veriable is unreliable.
+file is used, the &$tls_in_ourcert$& variable is unreliable.

 
 &*Note*&: OCSP stapling is not usable under OpenSSL
 when a list of more than one file is used.
 
 &*Note*&: OCSP stapling is not usable under OpenSSL
 when a list of more than one file is used.


@@ -24242,7 +24247,7 @@ as the initiator must present a cookie in the SYN segment.
 On (at least some) current Linux distributions the facility must be enabled
 in the kernel by the sysadmin before the support is usable.
 There is no option for control of the server side; if the system supports
 On (at least some) current Linux distributions the facility must be enabled
 in the kernel by the sysadmin before the support is usable.
 There is no option for control of the server side; if the system supports

-it it is always enebled.  Note that legthy operations in the connect ACL,
+it it is always enabled.  Note that lengthy operations in the connect ACL,

 such as DNSBL lookups, will still delay the emission of the SMTP banner.
 
 .option hosts_try_prdr smtp "host list&!!" *
 such as DNSBL lookups, will still delay the emission of the SMTP banner.
 
 .option hosts_try_prdr smtp "host list&!!" *


@@ -27424,8 +27429,8 @@ tls_require_ciphers = ${if =={$received_port}{25}\
 When Exim has been built with TLS support, it advertises the availability of
 the STARTTLS command to client hosts that match &%tls_advertise_hosts%&,
 but not to any others. The default value of this option is *, which means
 When Exim has been built with TLS support, it advertises the availability of
 the STARTTLS command to client hosts that match &%tls_advertise_hosts%&,
 but not to any others. The default value of this option is *, which means

-that STARTTLS is alway advertised.  Set it to blank to never advertise;
-this is reasonble for systems that want to use TLS only as a client.
+that STARTTLS is always advertised.  Set it to blank to never advertise;
+this is reasonable for systems that want to use TLS only as a client.

 
 If STARTTLS is to be used you
 need to set some other options in order to make TLS available.
 
 If STARTTLS is to be used you
 need to set some other options in order to make TLS available.


@@ -27858,7 +27863,7 @@ unencrypted data stream from and to the delivery processes.
 
 An older mode of operation can be enabled on a per-host basis by the
 &%hosts_noproxy_tls%& option on the &(smtp)& transport.  If the host matches
 
 An older mode of operation can be enabled on a per-host basis by the
 &%hosts_noproxy_tls%& option on the &(smtp)& transport.  If the host matches

-this list the proxy process descibed above is not used; instead Exim
+this list the proxy process described above is not used; instead Exim

 shuts down an existing TLS session being run by the delivery process
 before passing the socket to a new process. The new process may then
 try to start a new TLS session, and if successful, may try to re-authenticate
 shuts down an existing TLS session being run by the delivery process
 before passing the socket to a new process. The new process may then
 try to start a new TLS session, and if successful, may try to re-authenticate


@@ -31134,7 +31139,7 @@ This option applies to recipient callouts only. For example:
 .code
 require  verify = recipient/callout=use_sender,hold
 .endd
 .code
 require  verify = recipient/callout=use_sender,hold
 .endd

-It causes the connection to be helod open and used for any further recipients
+It causes the connection to be held open and used for any further recipients

 and for eventual delivery (should that be done quickly).
 Doing this saves on TCP and SMTP startup costs, and TLS costs also
 when that is used for the connections.
 and for eventual delivery (should that be done quickly).
 Doing this saves on TCP and SMTP startup costs, and TLS costs also
 when that is used for the connections.


@@ -32363,7 +32368,7 @@ All parts contained within an attachment multipart are attachments.
 
 As an example, the following will ban &"HTML mail"& (including that sent with
 alternative plain text), while allowing HTML files to be attached. HTML
 
 As an example, the following will ban &"HTML mail"& (including that sent with
 alternative plain text), while allowing HTML files to be attached. HTML

-coverletter mail attached to non-HMTL coverletter mail will also be allowed:
+coverletter mail attached to non-HTML coverletter mail will also be allowed:

 .code
 deny message = HTML mail is not accepted here
 !condition = $mime_is_rfc822
 .code
 deny message = HTML mail is not accepted here
 !condition = $mime_is_rfc822


@@ -36334,7 +36339,7 @@ the &"=>"& line, tagged with S=.
 .new
 .cindex log "DKIM verification"
 .cindex DKIM "verification logging"
 .new
 .cindex log "DKIM verification"
 .cindex DKIM "verification logging"

-&%dkim%&: For message acceptance log lines, when an DKIM signture in the header
+&%dkim%&: For message acceptance log lines, when an DKIM signature in the header

 verifies successfully a tag of DKIM is added, with one of the verified domains.
 .next
 .cindex log "DKIM verification"
 verifies successfully a tag of DKIM is added, with one of the verified domains.
 .next
 .cindex log "DKIM verification"


@@ -36413,7 +36418,7 @@ connection is unexpectedly dropped.
 .next
 .cindex "log" "millisecond timestamps"
 .cindex millisecond logging
 .next
 .cindex "log" "millisecond timestamps"
 .cindex millisecond logging

-.cindex timstamps "millisecond, in logs"
+.cindex timestamps "millisecond, in logs"

 &%millisec%&: Timestamps have a period and three decimal places of finer granularity
 appended to the seconds value.
 .next
 &%millisec%&: Timestamps have a period and three decimal places of finer granularity
 appended to the seconds value.
 .next


@@ -36428,7 +36433,7 @@ followed by IP address in square brackets. You can disable this by turning
 off the &%outgoing_interface%& option.
 .next
 .cindex "log" "outgoing remote port"
 off the &%outgoing_interface%& option.
 .next
 .cindex "log" "outgoing remote port"

-.cindex "port" "logging outgoint remote"
+.cindex "port" "logging outgoing remote"

 .cindex "TCP/IP" "logging outgoing remote port"
 &%outgoing_port%&: The remote port number is added to delivery log lines (those
 containing => tags) following the IP address.
 .cindex "TCP/IP" "logging outgoing remote port"
 &%outgoing_port%&: The remote port number is added to delivery log lines (those
 containing => tags) following the IP address.


@@ -38594,7 +38599,7 @@ There is no dot-stuffing (and no dot-termination).
 DKIM is a mechanism by which messages sent by some entity can be provably
 linked to a domain which that entity controls.  It permits reputation to
 be tracked on a per-domain basis, rather than merely upon source IP address.
 DKIM is a mechanism by which messages sent by some entity can be provably
 linked to a domain which that entity controls.  It permits reputation to
 be tracked on a per-domain basis, rather than merely upon source IP address.

-DKIM is documented in RFC 4871.
+DKIM is documented in RFC 6376.

 
 .new
 As DKIM relies on the message being unchanged in transit, messages handled
 
 .new
 As DKIM relies on the message being unchanged in transit, messages handled


@@ -38656,7 +38661,12 @@ rsa-sha1 MUST NOT be used for signing or verifying.
 Signers MUST use RSA keys of at least 1024 bits for all keys.
 Signers SHOULD use RSA keys of at least 2048 bits.
 .endd
 Signers MUST use RSA keys of at least 1024 bits for all keys.
 Signers SHOULD use RSA keys of at least 2048 bits.
 .endd

-.wen
+
+Note also that the key content (the 'p=' field)
+in the DNS record is different between RSA and EC keys;
+for the former it is the base64 of the ASN.1 for the RSA public key
+(equivalent to the private-key .pem with the header/trailer stripped)
+but for EC keys it is the base64 of the pure key; no ASN.1 wrapping.

 .wen
 
 Signing is enabled by setting private options on the SMTP transport.
 .wen
 
 Signing is enabled by setting private options on the SMTP transport.


@@ -38685,10 +38695,14 @@ You can use the &%$dkim_domain%& and
 &%$dkim_selector%& expansion variables to determine the private key to use.
 The result can either
 .ilist
 &%$dkim_selector%& expansion variables to determine the private key to use.
 The result can either
 .ilist

-be a valid RSA private key in ASCII armor, including line breaks.
+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)
+.wen

 .next
 start with a slash, in which case it is treated as a file that contains
 .next
 start with a slash, in which case it is treated as a file that contains

-the private key.
+the private key

 .next
 be "0", "false" or the empty string, in which case the message will not
 be signed. This case will not result in an error, even if &%dkim_strict%&
 .next
 be "0", "false" or the empty string, in which case the message will not
 be signed. This case will not result in an error, even if &%dkim_strict%&


@@ -38701,6 +38715,15 @@ Note that RFC 8301 says:
 Signers MUST use RSA keys of at least 1024 bits for all keys.
 Signers SHOULD use RSA keys of at least 2048 bits.
 .endd
 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/).
+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)
+for some transition period.
+The "_CRYPTO_SIGN_ED25519" macro will be defined if support is present
+for EC keys.

 .wen
 
 .option dkim_hash smtp string&!! sha256
 .wen
 
 .option dkim_hash smtp string&!! sha256


@@ -38744,7 +38767,7 @@ whether or not each header is present in the message.
 The default list is available for the expansion in the macro
 "_DKIM_SIGN_HEADERS".
 
 The default list is available for the expansion in the macro
 "_DKIM_SIGN_HEADERS".
 

-If a name is repeated, multiple headers by that name (or the absence therof)
+If a name is repeated, multiple headers by that name (or the absence thereof)

 will be signed.  The textually later headers in the headers part of the
 message are signed first, if there are multiples.
 
 will be signed.  The textually later headers in the headers part of the
 message are signed first, if there are multiples.
 


@@ -38752,7 +38775,7 @@ A name can be prefixed with either an '=' or a '+' character.
 If an '=' prefix is used, all headers that are present with this name
 will be signed.
 If a '+' prefix if used, all headers that are present with this name
 If an '=' prefix is used, all headers that are present with this name
 will be signed.
 If a '+' prefix if used, all headers that are present with this name

-will be signed, and one signtature added for a missing header with the
+will be signed, and one signature added for a missing header with the

 name will be appended.
 
 
 name will be appended.
 
 


@@ -38883,6 +38906,11 @@ The key record selector string.
 
 .vitem &%$dkim_algo%&
 The algorithm used. One of 'rsa-sha1' or 'rsa-sha256'.
 
 .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'.
+The "_CRYPTO_SIGN_ED25519" macro will be defined if support is present
+for EC keys.
+.wen

 
 .new
 Note that RFC 8301 says:
 
 .new
 Note that RFC 8301 says:


@@ -39424,7 +39452,7 @@ the "headers charset" command (in a filter file)
 or &%headers_charset%& main configuration option (otherwise),
 to the
 modified UTF-7 encoding specified by RFC 2060,
 or &%headers_charset%& main configuration option (otherwise),
 to the
 modified UTF-7 encoding specified by RFC 2060,

-with the following exception: All occurences of <sep>
+with the following exception: All occurrences of <sep>

 (which has to be a single character)
 are replaced with periods ("."), and all periods and slashes that are not
 <sep> and are not in the <specials> string are BASE64 encoded.
 (which has to be a single character)
 are replaced with periods ("."), and all periods and slashes that are not
 <sep> and are not in the <specials> string are BASE64 encoded.


@@ -39510,7 +39538,7 @@ The second column in the table above describes whether the event fires
 before or after the action is associates with.  Those which fire before
 can be used to affect that action (more on this below).
 
 before or after the action is associates with.  Those which fire before
 can be used to affect that action (more on this below).
 

-The third column in the table above says what section of the configumration
+The third column in the table above says what section of the configuration

 should define the event action.
 
 An additional variable, &$event_data$&, is filled with information varying
 should define the event action.
 
 An additional variable, &$event_data$&, is filled with information varying