From: Jeremy Harris Date: Fri, 10 Jan 2020 12:07:19 +0000 (+0000) Subject: Docs: add explicit warnings for some variables likely tainted X-Git-Url: https://git.exim.org/users/jgh/exim.git/commitdiff_plain/1ea7f48754621db22ec40b6362823433d54bda62 Docs: add explicit warnings for some variables likely tainted --- diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 8b1522795..241540cfd 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -9815,6 +9815,12 @@ newline at the very end. For the &%header%& and &%bheader%& expansion, for those headers that contain lists of addresses, a comma is also inserted at the junctions between headers. This does not happen for the &%rheader%& expansion. +.new +.cindex "tainted data" +When the headers are from an incoming message, +the result of expanding any of these variables is tainted. +.wen + .vitem &*${hmac{*&<&'hashname'&>&*}{*&<&'secret'&>&*}{*&<&'string'&>&*}}*& .cindex "expansion" "hmac hashing" @@ -12192,6 +12198,12 @@ When the &%smtp_etrn_command%& option is being expanded, &$domain$& contains the complete argument of the ETRN command (see section &<>&). .endlist +.new +.cindex "tainted data" +If the origin of the data is an incoming message, +the result of expanding this variable is tainted. +.wen + .vitem &$domain_data$& .vindex "&$domain_data$&" @@ -12386,7 +12398,11 @@ because a message may have many recipients and the system filter is called just once. .new -&*Warning*&: the content of this variable is provided by a potential attacker. +.cindex "tainted data" +If the origin of the data is an incoming message, +the result of expanding this variable is tainted. + +&*Warning*&: the content of this variable is usually provided by a potential attacker. Consider carefully the implications of using it unvalidated as a name for file access. This presents issues for users' &_.forward_& and filter files.