NAME

       Mail::Milter::Wrapper::DecodeSRS - milter wrapper to decode SRS-encoded return path

SYNOPSIS

           use Mail::Milter::Wrapper::DecodeSRS;

           my $milter = ...;
           my $wrapper = new Mail::Milter::Wrapper::DecodeSRS($milter);

           my $wrapper2 = &DecodeSRS($milter); # convenience

DESCRIPTION

       Mail::Milter::Wrapper::DecodeSRS is a convenience milter wrapper which decodes MAIL FROM: return paths
       which have been encoded by the Sender Rewrite Scheme, SRS.  (More information:  http://www.libsrs2.org/)
       This wrapper internally understands both the SRS0 and SRS1 encoding schemes documented by the Mail::SRS
       author.

       The decoded address is made available to the contained milter via the "envfrom" callback, in the same way
       that a raw address would.

       NOTE:  If the address is not SRS encoded, the contained milter is NOT called for the duration of the
       message; instead, SMFIS_ACCEPT is returned.  This is because the milter writer is expected to use this
       wrapper in a chain that also includes the contained milter without wrapping, in order to prevent a
       malicious sender from using SRS to bypass access checks.

       For instance, the following is a proper usage of this wrapper in a chain:

           my $envfrommilter = ...;

           my $combinedmilter = new Mail::Milter::Chain(
               new Mail::Milter::Wrapper::UnwrapSRS($envfrommilter),
               $envfrommilter
           );

       This behavior can also be used if, e.g., the MTA already does one form of MAIL FROM: check, and the
       contained milter repeats that same database check against SRS rewritten addresses.  (A good example would
       be a milter emulating Sendmail's access_db map.)

AUTHOR

       Todd Vierling, <tv@duh.org> <tv@pobox.com>

SEE ALSO

       Mail::Milter::Wrapper