gpg: Make ASCII armor decoding more robust to encoding errors.

* g10/armor.c (radix64_read): If the = is followed by the string "3D",
check if the following four characters are valid radix 64 and are
followed by a new line.  If so, warn and ignore the '3D'.

--
Signed-off-by: Neal H. Walfield <neal@g10code.com>
GnuPG-bug-id: 2250
This commit is contained in:
Neal H. Walfield 2016-02-14 16:00:10 +01:00
parent a1c11283af
commit 2f02ed75a9
1 changed files with 18 additions and 0 deletions

View File

@ -796,6 +796,24 @@ radix64_read( armor_filter_context_t *afx, IOBUF a, size_t *retn,
}
}
/* Occasionally a bug MTA will leave the = escaped as
=3D. If the 4 characters following that are valid
Radix64 characters and they are following by a new
line, assume that this is the case and skip the
3D. */
if (afx->buffer_pos + 6 < afx->buffer_len
&& afx->buffer[afx->buffer_pos + 0] == '3'
&& afx->buffer[afx->buffer_pos + 1] == 'D'
&& asctobin[afx->buffer[afx->buffer_pos + 2]] != 255
&& asctobin[afx->buffer[afx->buffer_pos + 3]] != 255
&& asctobin[afx->buffer[afx->buffer_pos + 4]] != 255
&& asctobin[afx->buffer[afx->buffer_pos + 5]] != 255
&& afx->buffer[afx->buffer_pos + 6] == '\n')
{
afx->buffer_pos += 2;
afx->qp_detected = 1;
}
if (!n)
onlypad = 1;