From: Jeremy Harris Date: Thu, 18 Jun 2020 19:27:52 +0000 (+0100) Subject: Docs: tidy more uses of tainted variables X-Git-Tag: exim-4.95-RC0~315 X-Git-Url: https://git.exim.org/exim.git/commitdiff_plain/6e2400bf8b3c728f5bf8af52054fcab4e2351e21 Docs: tidy more uses of tainted variables --- diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 874ef31cf..e29f1333a 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -12472,7 +12472,8 @@ the complete argument of the ETRN command (see section &<>&). .cindex "tainted data" If the origin of the data is an incoming message, -the result of expanding this variable is tainted. +the result of expanding this variable is tainted and may not +be further expanded or used as a filename. When an untainted version is needed, one should be obtained from looking up the value in a local (therefore trusted) database. Often &$domain_data$& is usable in this role. @@ -12672,7 +12673,8 @@ once. .cindex "tainted data" If the origin of the data is an incoming message, -the result of expanding this variable is tainted. +the result of expanding this variable is tainted and +may not be further expanded or used as a filename. &*Warning*&: the content of this variable is usually provided by a potential attacker. @@ -35474,14 +35476,14 @@ address if its delivery failed. .section "Per-address filtering" "SECTperaddfil" -.vindex "&$domain$&" -.vindex "&$local_part$&" +.vindex "&$domain_data$&" +.vindex "&$local_part_data$&" In contrast to the system filter, which is run just once per message for each delivery attempt, it is also possible to set up a system-wide filtering operation that runs once for each recipient address. In this case, variables -such as &$local_part$& and &$domain$& can be used, and indeed, the choice of -filter file could be made dependent on them. This is an example of a router -which implements such a filter: +such as &$local_part_data$& and &$domain_data$& can be used, +and indeed, the choice of filter file could be made dependent on them. +This is an example of a router which implements such a filter: .code central_filter: check_local_user @@ -37302,7 +37304,7 @@ follows: .code my_mailboxes: driver = appendfile - file = /var/mail/$domain/$local_part_data + file = /var/mail/$domain_data/$local_part_data user = mail .endd This uses a directory of mailboxes for each domain. The &%user%& setting is @@ -37342,7 +37344,7 @@ It runs a user's &_.forward_& file for all local parts of the form cases by testing the variable &$local_part_suffix$&. For example: .code if $local_part_suffix contains -special then -save /home/$local_part/Mail/special +save /home/$local_part_data/Mail/special endif .endd If the filter file does not exist, or does not deal with such addresses, they