From: Tom Kistner Date: Fri, 16 Oct 2009 08:52:05 +0000 (+0000) Subject: DKIM Doc update X-Git-Tag: exim-4_70_RC3~37 X-Git-Url: https://vcs.fsf.org/?a=commitdiff_plain;h=6afc838341d15248134205300a73eceea777cee5;p=exim.git DKIM Doc update --- diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index fa29a2524..db8de0805 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -1,4 +1,4 @@ -. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.57 2009/10/16 08:49:47 tom Exp $ +. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.58 2009/10/16 08:52:05 tom Exp $ . . ///////////////////////////////////////////////////////////////////////////// . This is the primary source of the Exim Manual. It is an xfpt document that is @@ -34406,39 +34406,48 @@ runtime of the ACL. 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 -&%$dkim_signing_domains%& exist. +&%$dkim_signers%& exist. The global option &%dkim_verify_signers%& can be set to a colon-separated list of DKIM domains or identities for which the ACL &%acl_smtp_dkim%& is called. It is expanded when the message has been received. At this point, -the expansion variable &%$dkim_signing_domains%& already contains a colon- -separated list of signer domains for the message. When &%dkim_verify_signers%& -is not specified in the main configuration, it defaults as: +the expansion variable &%$dkim_signers%& already contains a colon- +separated list of signer domains and identities for the message. When +&%dkim_verify_signers%& is not specified in the main configuration, +it defaults as: .code -dkim_verify_signers = $dkim_signing_domains +dkim_verify_signers = $dkim_signers .endd This leads to the default behaviour of calling &%acl_smtp_dkim%& for each DKIM signature in the message. Current DKIM verifiers may want to explicitly call the ACL for known domains or identities. This would be achieved as follows: .code -dkim_verify_signers = paypal.com:ebay.com:$dkim_signing_domains +dkim_verify_signers = paypal.com:ebay.com:$dkim_signers .endd This would result in &%acl_smtp_dkim%& always being called for "paypal.com" -and "ebay.com", plus all domains that have signatures in the message. You can -also be more creative in constructing your policy. Example: +and "ebay.com", plus all domains and identities that have signatures in the message. +You can also be more creative in constructing your policy. Example: .code -dkim_verify_signers = $sender_address_domain:$dkim_signing_domains +dkim_verify_signers = $sender_address_domain:$dkim_signers .endd +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. + + Inside the &%acl_smtp_dkim%&, the following expansion variables are available (from most to least important): .vlist +.vitem &%$dkim_cur_signer%& +The signer that is being evaluated in this ACL run. This can be domain or +an identity. This is one of the list items from the expanded main option +&%dkim_verify_signers%& (see above). .vitem &%$dkim_verify_status%& A string describing the general status of the signature. One of .ilist &%none%&: There is no signature in the message for the current domain or -identity. +identity (as reflected by &%$dkim_cur_signer%&). .next &%invalid%&: The signature could not be verified due to a processing error. More detail is available in &%$dkim_verify_reason%&. @@ -34469,14 +34478,12 @@ DKIM verification. It may of course also mean that the signature is forged. .endlist .vitem &%$dkim_domain%& The signing domain. IMPORTANT: This variable is only populated if there is -ab actual signature in the message. It does NOT neccessarily carry the -domain that is currently being evaluated. Please use the &%dkim_signers%& ACL -condition for that. +an actual signature in the message for the current domain or identity (as +reflected by &%$dkim_cur_signer%&). .vitem &%$dkim_identity%& -The signing identity. IMPORTANT: This variable is only populated if there is -ab actual signature in the message. It does NOT neccessarily carry the -identity that is currently being evaluated. Please use the &%dkim_signers%& ACL -condition for that. +The signing identity, if present. IMPORTANT: This variable is only populated +if there is an actual signature in the message for the current domain or +identity (as reflected by &%$dkim_cur_signer%&). .vitem &%$dkim_selector%& The key record selector string .vitem &%$dkim_algo%& @@ -34521,8 +34528,9 @@ In addition, two ACL conditions are provided: .vlist .vitem &%dkim_signers%& ACL condition that checks a colon-separated list of domains or identities -for a match against the domain or identity that the ACL is currently verifying. -This is typically used to restrict an ACL verb to a group of domains or identities, like: +for a match against the domain or identity that the ACL is currently verifying +(reflected by &%$dkim_cur_signer%&). This is typically used to restrict an ACL +verb to a group of domains or identities, like: .code # Warn when message apparently from GMail has no signature at all