--- Begin Message ---
Package: release.debian.org
Severity: normal
Tags: bullseye
User: release.debian....@packages.debian.org
Usertags: pu
X-Debbugs-Cc: amavisd-...@packages.debian.org, b...@debian.org
Control: affects -1 + src:amavisd-new
[ Reason ]
* Fix CVE-2024-28054.
[ Impact ]
Without this path:
* CVE-2024-28054 won't be fixed, and amavisd-new could potentially let through
mallacious emails.
[ Tests ]
No tests.
[ Risks ]
Patch could break with risk that geniune emails get blocked.
[ Checklist ]
[X] *all* changes are documented in the d/changelog
[X] I reviewed all changes and I approve them
[X] attach debdiff against the package in (old)stable
[X] the issue is verified as fixed in unstable
[ Changes ]
As below.
[ Other info ]
Patch could break with risk that geniune emails get blocked.
[ Checklist ]
[X] *all* changes are documented in the d/changelog
[X] I reviewed all changes and I approve them
[X] attach debdiff against the package in (old)stable
[X] the issue is verified as fixed in unstable
[ Changes ]
As below.
[ Other info ]
I hope I am doing this right :-)
I accidentally uploaded 2.11.1-6, I tried to delete it, but if that didn't
work, please just delete.
=== deb diff ===
diff -Nru amavisd-new-2.11.1/debian/changelog
amavisd-new-2.11.1/debian/changelog
--- amavisd-new-2.11.1/debian/changelog 2021-06-07 22:51:44.000000000 +0000
+++ amavisd-new-2.11.1/debian/changelog 2024-03-31 07:16:32.000000000 +0000
@@ -1,3 +1,10 @@
+amavisd-new (1:2.11.1-5+deb11u1) oldstable; urgency=medium
+
+ * CVE-2024-28054: Handle multiple boundary parameters that contain
+ conflicting values.
+
+ -- Brian May <b...@debian.org> Sun, 31 Mar 2024 18:16:32 +1100
+
amavisd-new (1:2.11.1-5) unstable; urgency=medium
* Add missing dependency on libnet-snmp-perl. Closes: #936052.
diff -Nru amavisd-new-2.11.1/debian/gbp.conf amavisd-new-2.11.1/debian/gbp.conf
--- amavisd-new-2.11.1/debian/gbp.conf 1970-01-01 00:00:00.000000000 +0000
+++ amavisd-new-2.11.1/debian/gbp.conf 2024-03-31 07:16:32.000000000 +0000
@@ -0,0 +1,2 @@
+[DEFAULT]
+debian-branch=debian/bullseye
diff -Nru amavisd-new-2.11.1/debian/patches/0011-fix-CVE-2024-28054
amavisd-new-2.11.1/debian/patches/0011-fix-CVE-2024-28054
--- amavisd-new-2.11.1/debian/patches/0011-fix-CVE-2024-28054 1970-01-01
00:00:00.000000000 +0000
+++ amavisd-new-2.11.1/debian/patches/0011-fix-CVE-2024-28054 2024-03-31
07:15:01.000000000 +0000
@@ -0,0 +1,175 @@
+--- /dev/null
++++ b/README_FILES/README.CVE-2024-28054
+@@ -0,0 +1,54 @@
++# Problem description
++
++Emails which consist of multiple parts (`Content-Type: multipart/*`)
++incorporate boundary information stating at which point one part ends and the
++next part begins.
++
++A boundary is announced by an Content-Type header's `boundary` parameter. To
++our current knowledge, RFC2046 and RFC2045 do not explicitly specify how a
++parser should handle multiple boundary parameters that contain conflicting
++values. As a result, there is no canonical choice which of the values should
or
++should not be used for mime part decomposition.
++
++It turns out that MIME::Parser from MIME-tools chooses the last `boundary`
++parameter of a Content-Type-header, while several mail user agents choose the
++first occuring one. As a consequence, Amavis will apply some of its routines
to
++content that a receiving MUA will not see, and vice-versa will not apply them
++to content that the receiving MUA will see. Such routines are at least
++- the banned-files check, and
++- the virus check, unless
++ - Amavis feeds the whole email into the virus scanner, and
++ - the virus scanner implements its own email parsing that aligns with the
++ receiving MUA's parser implementation.
++
++MIME::Parser does not provide a choice which of multiple `boundary` parameters
++shall be used for parsing, but it will give feedback in such a case [1], which
++Amavis can react to.
++Emails with ambiguous content, like multiple `boundary` parameters as
described
++above, will be categorized as `CC_UNCHECKED,3`, since Amavis has no
information
++about the recipient's MUA's parser implementation.
++
++# Recommendation
++
++Legitimate emails are not expected to have ambiguous content, so an Amavis
setup
++should treat them harshly. The new default configuration for `CC_UNCHECKED,3`
is
++defanging:
++
++```
++$defang_by_ccat{CC_UNCHECKED.",3"} = 1; # ambiguous content (e.g. multipart
boundary)
++```
++
++Another possibility would be quarantining, e.g. via
++
++```
++$quarantine_to_maps_by_ccat{CC_UNCHECKED.",3"} = [1];
++$quarantine_method_by_ccat{CC_UNCHECKED.",3"} =
'local:unchecked-ambiguous-%m';
++```
++
++and/or discarding/rejecting the email:
++
++```
++$final_destiny_maps_by_ccat{CC_UNCHECKED.",3"} = D_REJECT; # or D_DISCARD
++```
++
++[1] https://metacpan.org/release/DSKOLL/MIME-tools-5.514/changes
+--- a/amavisd
++++ b/amavisd
+@@ -1374,6 +1374,7 @@
+ CC_UNCHECKED, 'Unchecked',
+ CC_UNCHECKED.',1', 'UncheckedEncrypted',
+ CC_UNCHECKED.',2', 'UncheckedOverLimits',
++ CC_UNCHECKED.',3', 'UncheckedAmbiguousContent',
+ CC_BANNED, 'Banned',
+ CC_VIRUS, 'Virus',
+ );
+@@ -1844,6 +1845,7 @@
+ CC_BANNED, 'id=%n - BANNED: %F',
+ CC_UNCHECKED.',1', 'id=%n - UNCHECKED: encrypted',
+ CC_UNCHECKED.',2', 'id=%n - UNCHECKED: over limits',
++ CC_UNCHECKED.',3', 'id=%n - UNCHECKED: ambiguous content',
+ CC_UNCHECKED, 'id=%n - UNCHECKED',
+ CC_SPAM, 'id=%n - spam',
+ CC_SPAMMY.',1', 'id=%n - spammy (tag3)',
+@@ -9946,7 +9948,8 @@
+ sub attributes # a string of characters representing attributes
+ { @_<2 ? shift->{attr} : ($_[0]->{attr} = $_[1]) };
+
+-sub attributes_add { # U=undecodable, C=crypted, D=directory,S=special,L=link
++sub attributes_add { # U=undecodable, C=crypted, B=ambiguous-content,
++ # D=directory, S=special, L=link
+ my $self = shift; my $a = $self->{attr}; $a = '' if !defined $a;
+ for my $arg (@_) { $a .= $arg if $arg ne '' && index($a,$arg) < 0 }
+ $self->{attr} = $a;
+@@ -10405,6 +10408,24 @@
+ }
+ }
+
++sub ambiguous_content {
++ my $entity = shift;
++ if ($entity->can('ambiguous_content')) {
++ return $entity->ambiguous_content;
++ } else {
++ return unless $entity->is_multipart;
++ my $content_type = $entity->head->get('Content-Type');
++ if ($content_type && $content_type =~ m{^multipart/\w+(.+)}x) {
++ my ($params, $num) = ($1, 0);
++ while ($params =~ m{\G ; \s+ (?<param>\w+) = (?: \w+ |
"(?:\\.|[^"\\])*" )}gx) {
++ $num++ if lc($+{param}) eq 'boundary';
++ }
++ return $num > 1;
++ }
++ return;
++ }
++}
++
+ # traverse MIME::Entity object depth-first,
+ # extracting preambles and epilogues as extra (pseudo)parts, and
+ # filling-in additional information into Amavis::Unpackers::Part objects
+@@ -10419,6 +10440,7 @@
+ if (!defined($body)) { # a MIME container only contains parts, no bodypart
+ # create pseudo-part objects for MIME containers (e.g. multipart/* )
+ $part = Amavis::Unpackers::Part->new(undef,$parent_obj,1);
++ $part->attributes_add('B') if ambiguous_content($entity);
+ # $part->type_short('no-file');
+ do_log(2, "%s %s Content-Type: %s", $part->base_name, $placement, $mt);
+
+@@ -14572,16 +14594,18 @@
+
+ $which_section = "parts_decode_ext";
+ snmp_count('OpsDec');
+- my($any_encrypted,$over_levels);
+- ($hold, $any_undecipherable, $any_encrypted, $over_levels) =
++ my($any_encrypted,$over_levels,$ambiguous);
++ ($hold, $any_undecipherable, $any_encrypted, $over_levels, $ambiguous) =
+ Amavis::Unpackers::decompose_mail($msginfo->mail_tempdir,
+ $file_generator_object);
+- $any_undecipherable ||= ($any_encrypted || $over_levels);
++ $any_undecipherable ||= ($any_encrypted || $over_levels || $ambiguous);
+ if ($any_undecipherable) {
+ $msginfo->add_contents_category(CC_UNCHECKED,0);
+ $msginfo->add_contents_category(CC_UNCHECKED,1) if $any_encrypted;
+ $msginfo->add_contents_category(CC_UNCHECKED,2) if $over_levels;
++ $msginfo->add_contents_category(CC_UNCHECKED,3) if $ambiguous;
+ for my $r (@{$msginfo->per_recip_data}) {
++ $r->add_contents_category(CC_UNCHECKED,3) if $ambiguous;
+ next if $r->bypass_virus_checks;
+ $r->add_contents_category(CC_UNCHECKED,0);
+ $r->add_contents_category(CC_UNCHECKED,1) if $any_encrypted;
+@@ -31643,7 +31667,7 @@
+ my($tempdir,$file_generator_object) = @_;
+
+ my $hold; my(@parts); my $depth = 1;
+- my($any_undecipherable, $any_encrypted, $over_levels) = (0,0,0);
++ my($any_undecipherable, $any_encrypted, $over_levels, $ambiguous) =
(0,0,0,0);
+ my $which_section = "parts_decode";
+ # fetch all not-yet-visited part names, and start a new cycle
+ TIER:
+@@ -31705,13 +31729,14 @@
+ if (defined $attr) {
+ $any_undecipherable++ if index($attr, 'U') >= 0;
+ $any_encrypted++ if index($attr, 'C') >= 0;
++ $ambiguous++ if index($attr, 'B') >= 0;
+ }
+ }
+ last TIER if defined $hold;
+ $depth++;
+ }
+ section_time($which_section); prolong_timer($which_section);
+- ($hold, $any_undecipherable, $any_encrypted, $over_levels);
++ ($hold, $any_undecipherable, $any_encrypted, $over_levels, $ambiguous);
+ }
+
+ # Decompose one part
+--- a/amavisd.conf
++++ b/amavisd.conf
+@@ -145,6 +145,7 @@
+ $defang_by_ccat{CC_BADH.",3"} = 1; # NUL or CR character in header
+ $defang_by_ccat{CC_BADH.",5"} = 1; # header line longer than 998 characters
+ $defang_by_ccat{CC_BADH.",6"} = 1; # header field syntax error
++$defang_by_ccat{CC_UNCHECKED.",3"} = 1; # ambiguous content (e.g. multipart
boundary)
+
+
+ # OTHER MORE COMMON SETTINGS (defaults may suffice):
diff -Nru amavisd-new-2.11.1/debian/patches/series
amavisd-new-2.11.1/debian/patches/series
--- amavisd-new-2.11.1/debian/patches/series 2020-03-21 22:34:14.000000000
+0000
+++ amavisd-new-2.11.1/debian/patches/series 2024-03-31 07:15:01.000000000
+0000
@@ -8,3 +8,4 @@
95_amavisd_helpers_fixes
0009-Fix-an-unescaped-brace-in-amavisd.patch
0010-fix-882324.patch
+0011-fix-CVE-2024-28054
--- End Message ---
