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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/doc-txt/NewStuff | 90 |
1 files changed, 89 insertions, 1 deletions
diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index f74d31742..65b0fc678 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.49 2005/06/14 13:48:40 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/NewStuff,v 1.50 2005/06/16 20:03:43 tom Exp $ New Features in Exim -------------------- @@ -255,6 +255,94 @@ PH/02 There's a new verify callout option, "fullpostmaster", which first acts PH/03 The action of the auto_thaw option has been changed. It no longer applies to frozen bounce messages. +TK/02 There are two new expansion items to help with the implementation of + the BATV "prvs" scheme in an Exim configuration: + + + ${prvs {<ADDRESS>}{<KEY>}{[KEYNUM]}} + + The "prvs" expansion item takes three arguments: A qualified RFC2821 + email address, a key and an (optional) key number. All arguments are + expanded before being used, so it is easily possible to lookup a key + and key number using the address as the lookup key. The key number is + optional and defaults to "0". The item will expand to a "prvs"-signed + email address, to be typically used with the "return_path" option on + a smtp transport. The decision if BATV should be used with a given + sender/recipient pair should be done on router level, to avoid having + to set "max_rcpt = 1" on the transport. + + + ${prvscheck {<ADDRESS>}{<SECRET>}{<RETURN_STRING>}} + + The "prvscheck" expansion item takes three arguments. Argument 1 is + expanded first. When the expansion does not yield a SYNTACTICALLY + valid "prvs"-scheme address, the whole "prvscheck" item expands to + the empty string. If <ADDRESS> is a "prvs"-encoded address after + expansion, two expansion variables are set up: + + $prvscheck_address Contains the "prvs"-decoded version of + the address from argument 1. + + $prvscheck_keynum Contains the key number extracted from + the "prvs"-address in argument 1. + + These two variables can be used in the expansion code of argument 2 + to retrieve the <SECRET>. The VALIDITY of the "prvs"-signed address + is then checked. The result is stored in yet another expansion + variable: + + $prvscheck_result Contains the result of a "prvscheck" + expansion: Unset (the empty string) for + failure, "1" for success. + + The "prvscheck" expansion expands to the empty string if <ADDRESS> + is not a SYNTACTICALLY valid "prvs"-scheme address. Otherwise, + argument 3 defines what "prvscheck" expands to: If argument 3 + is the empty string, "prvscheck" expands to the decoded version + of the address (no matter if it is CRYPTOGRAPHICALLY valid or not). + If argument 3 expands to a non-empty string, "prvscheck" expands + to that string. + + + Usage example + ------------- + + Macro: + + PRVSCHECK_SQL = ${lookup mysql{SELECT secret FROM batv_prvs WHERE \ + sender='${quote_mysql:$prvscheck_address}'}{$value}} + + RCPT ACL: + + # Bounces: drop unsigned addresses for BATV senders + deny message = This address does not send an unsigned reverse path. + senders = : + recipients = +batv_recipients + + # Bounces: In case of prvs-signed address, check signature. + deny message = Invalid reverse path signature. + senders = : + condition = ${prvscheck {$local_part@$domain}{PRVSCHECK_SQL}{1}} + !condition = $prvscheck_result + + Top-Level Router: + + batv_redirect: + driver = redirect + data = ${prvscheck {$local_part@$domain}{PRVSCHECK_SQL}{}} + + Transport (referenced by router that makes decision if + BATV is applicable): + + external_smtp_batv: + driver = smtp + return_path = ${prvs {$return_path} \ + {${lookup mysql{SELECT \ + secret FROM batv_prvs WHERE \ + sender='${quote_mysql:$sender_address}'} \ + {$value}fail}}} + + Version 4.51 ------------ |