Dpkg::Control::HashCore: Fix OpenPGP Armor Header Line parsing

We should only accept [\r\t ] as trailing whitespace, although RFC4880
does not clarify what whitespace really maps to, we should really match
the GnuPG implementation anyway, as that is what we use to verify the
signatures.

Fixes: CVE-2015-0840
Reported-by: Jann Horn <jann@thejh.net>

diff --git a/scripts/Dpkg/Control/Hash.pm b/scripts/Dpkg/Control/Hash.pm
index b142876..a21b75d 100644 (file)
--- a/scripts/Dpkg/Control/Hash.pm
+++ b/scripts/Dpkg/Control/Hash.pm
@@ -175,19 +175,21 @@ sub parse {
     my $pgp_signed = 0;
 
     while (<$fh>) {
-       s/\s*\n$//;
-       next if (m/^$/ and $paraborder);
+       chomp;
+       next if m/^\s*$/ and $paraborder;
        next if (m/^#/);
        $paraborder = 0;
        if (m/^(\S+?)\s*:\s*(.*)$/) {
            $parabody = 1;
-           if (exists $self->{$1}) {
+           my ($name, $value) = ($1, $2);
+           if (exists $self->{$name}) {
                unless ($$self->{'allow_duplicate'}) {
-                   syntaxerr($desc, sprintf(_g("duplicate field %s found"), $1));
+                   syntaxerr($desc, sprintf(_g("duplicate field %s found"), $name));
                }
            }
-           $self->{$1} = $2;
-           $cf = $1;
+           $value =~ s/\s*$//;
+           $self->{$name} = $value;
+           $cf = $name;
        } elsif (m/^\s(\s*\S.*)$/) {
            my $line = $1;
            unless (defined($cf)) {
@@ -196,8 +198,9 @@ sub parse {
            if ($line =~ /^\.+$/) {
                $line = substr $line, 1;
            }
+           $line =~ s/\s*$//;
            $self->{$cf} .= "\n$line";
-       } elsif (m/^-----BEGIN PGP SIGNED MESSAGE-----$/) {
+       } elsif (m/^-----BEGIN PGP SIGNED MESSAGE-----[\r\t ]*$/) {
            $expect_pgp_sig = 1;
            if ($$self->{'allow_pgp'} and not $parabody) {
                # Skip PGP headers
@@ -207,22 +210,23 @@ sub parse {
            } else {
                syntaxerr($desc, _g("PGP signature not allowed here"));
            }
-       } elsif (m/^$/ || ($expect_pgp_sig && m/^-----BEGIN PGP SIGNATURE-----$/)) {
+       } elsif (m/^\s*$/ ||
+                ($expect_pgp_sig && m/^-----BEGIN PGP SIGNATURE-----[\r\t ]*$/)) {
            if ($expect_pgp_sig) {
                # Skip empty lines
                $_ = <$fh> while defined($_) && $_ =~ /^\s*$/;
                length($_) ||
                     syntaxerr($desc, _g("expected PGP signature, found EOF " .
                                         "after blank line"));
-               s/\s*\n$//;
-               unless (m/^-----BEGIN PGP SIGNATURE-----$/) {
+               chomp;
+               unless (m/^-----BEGIN PGP SIGNATURE-----[\r\t ]*$/) {
                    syntaxerr($desc, sprintf(_g("expected PGP signature, " .
                                                 "found something else \`%s'"), $_));
                 }
                # Skip PGP signature
                while (<$fh>) {
-                   s/\s*\n$//;
-                   last if m/^-----END PGP SIGNATURE-----$/;
+                   chomp;
+                   last if m/^-----END PGP SIGNATURE-----[\r\t ]*$/;
                }
                unless (defined($_)) {
                     syntaxerr($desc, _g("unfinished PGP signature"));

diff --git a/scripts/Makefile.am b/scripts/Makefile.am
index fd63991..0289437 100644 (file)
--- a/scripts/Makefile.am
+++ b/scripts/Makefile.am
@@ -231,6 +231,7 @@ test_data = \
        t/700_Dpkg_Control/control-1 \
        t/700_Dpkg_Control/bogus-unsigned.dsc \
        t/700_Dpkg_Control/bogus-armor-double.dsc \
+       t/700_Dpkg_Control/bogus-armor-formfeed.dsc \
        t/700_Dpkg_Control/bogus-armor-no-sig.dsc \
        t/700_Dpkg_Control/bogus-armor-trail.dsc \
        t/700_Dpkg_Control/bogus-armor-inline.dsc \

diff --git a/scripts/t/700_Dpkg_Control.t b/scripts/t/700_Dpkg_Control.t
index 074e084..2331b10 100644 (file)
--- a/scripts/t/700_Dpkg_Control.t
+++ b/scripts/t/700_Dpkg_Control.t
@@ -13,7 +13,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-use Test::More tests => 22;
+use Test::More tests => 23;
 
 use strict;
 use warnings;
@@ -118,6 +118,9 @@ is($dsc, undef, 'Signed .dsc w/ bogus OpenPGP armor trailer');
 $dsc = parse_dsc("$datadir/bogus-armor-inline.dsc");
 is($dsc, undef, 'Signed .dsc w/ bogus OpenPGP inline armor');
 
+$dsc = parse_dsc("$datadir/bogus-armor-formfeed.dsc");
+is($dsc, undef, 'Signed .dsc w/ bogus OpenPGP armor line');
+
 $dsc = parse_dsc("$datadir/bogus-armor-double.dsc");
 ok(defined $dsc, 'Signed .dsc w/ two OpenPGP armor signatures');
 is($dsc->{Source}, 'pass', 'Signed spaced .dsc package name');

diff --git a/scripts/t/700_Dpkg_Control/bogus-armor-formfeed.dsc b/scripts/t/700_Dpkg_Control/bogus-armor-formfeed.dsc
new file mode 100644 (file)
index 0000000..70aab18
--- /dev/null
+++ b/scripts/t/700_Dpkg_Control/bogus-armor-formfeed.dsc
@@ -0,0 +1,19 @@
+-----BEGIN PGP SIGNED MESSAGE-----\f
+
+Source: fail
+
+-----BEGIN PGP SIGNATURE-----\f
+Version: vim v7.3.547 (GNU/Linux)
+
+Fake signature here.
+-----END PGP SIGNATURE-----\f
+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA1
+
+Source: pass
+
+-----BEGIN PGP SIGNATURE
+Version: GnuPG v1.4.12 (GNU/Linux)
+
+Valid signature here.
+-----END PGP SIGNATURE-----