gpg: Fix out-of-bound read in subpacket enumeration
authorWerner Koch <wk@gnupg.org>
Thu, 15 Mar 2018 07:44:52 +0000 (08:44 +0100)
committerWerner Koch <wk@gnupg.org>
Wed, 21 Mar 2018 18:43:33 +0000 (19:43 +0100)
commit983f7b2acbd1e7580652bbeb0c3d64f9dd19d9e4
tree64213aa325932b0a24136319388b36f91fad1aa3
parent11bbd99477ef5ba5b7db0c17607b10af03c68afb
gpg: Fix out-of-bound read in subpacket enumeration

* g10/parse-packet.c (enum_sig_subpkt): Check buflen before reading
the type octet.  Print diagnostic.
--

If the final subpacket has only a length header evaluating to zero and
missing the type octet, a read could happen right behind the buffer.
Valgrind detected this.  Fix is obvious.  Note that the further
parsing of the subpacket is still okay because it always checks the
length.  Note further that --list-packets uses a different code path
and already reported an error.

Reported-by: Philippe Antoine
He provided a test file copied below.  Running "gpg -v --verify" on it
triggered the bug.

-----BEGIN PGP ARMORED FILE-----
Comment: Use "gpg --dearmor" for unpacking

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=qYZP
-----END PGP ARMORED FILE-----

Signed-off-by: Werner Koch <wk@gnupg.org>
g10/parse-packet.c