diff options
| author | Guy Harris <guy@alum.mit.edu> | 2003-03-04 03:08:42 +0000 |
|---|---|---|
| committer | Guy Harris <guy@alum.mit.edu> | 2003-03-04 03:08:42 +0000 |
| commit | 6de0605087158fdfec1bd696aed2625ad1f3e49d (patch) | |
| tree | ed325eb8879ec9aa458665535fc6dd8d76a4c346 /packet-atm.c | |
| parent | 3cc105318208b3cfb499e7188a001762020d4672 (diff) | |
Attempt to better handle bogus AAL5 lengths (by assuming that the packet
doesn't have padding and the AAL5 trailer).
svn path=/trunk/; revision=7269
Diffstat (limited to 'packet-atm.c')
| -rw-r--r-- | packet-atm.c | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/packet-atm.c b/packet-atm.c index cf7be4a7d2..dfd574c4d7 100644 --- a/packet-atm.c +++ b/packet-atm.c @@ -1,7 +1,7 @@ /* packet-atm.c * Routines for ATM packet disassembly * - * $Id: packet-atm.c,v 1.61 2003/01/11 06:17:22 guy Exp $ + * $Id: packet-atm.c,v 1.62 2003/03/04 03:08:42 guy Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs <gerald@ethereal.com> @@ -1012,26 +1012,32 @@ dissect_reassembled_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, * to the trailer? */ aal5_length = tvb_get_ntohs(tvb, length - 6); - if (tree) { - pad_length = length - aal5_length - 8; - if (pad_length > 0) { + pad_length = length - aal5_length - 8; + /* + * Check for sanity in the AAL5 length; if it's not sane (i.e., + * if the amount of padding would be negative, or if we'd have more + * than one cell's worth of padding plus trailer), assume we don't + * padding and a trailer. + */ + if (pad_length > 0 && pad_length < 40) { + if (tree) { proto_tree_add_text(atm_tree, tvb, aal5_length, pad_length, "Padding"); - } - proto_tree_add_text(atm_tree, tvb, length - 8, 1, "AAL5 UU: 0x%02x", + proto_tree_add_text(atm_tree, tvb, length - 8, 1, "AAL5 UU: 0x%02x", tvb_get_guint8(tvb, length - 8)); - proto_tree_add_text(atm_tree, tvb, length - 7, 1, "AAL5 CPI: 0x%02x", + proto_tree_add_text(atm_tree, tvb, length - 7, 1, "AAL5 CPI: 0x%02x", tvb_get_guint8(tvb, length - 7)); - proto_tree_add_text(atm_tree, tvb, length - 6, 2, "AAL5 len: %u", + proto_tree_add_text(atm_tree, tvb, length - 6, 2, "AAL5 len: %u", aal5_length); - crc = tvb_get_ntohl(tvb, length - 4); - calc_crc = update_crc(0xFFFFFFFF, tvb_get_ptr(tvb, 0, length), + crc = tvb_get_ntohl(tvb, length - 4); + calc_crc = update_crc(0xFFFFFFFF, tvb_get_ptr(tvb, 0, length), length); - proto_tree_add_text(atm_tree, tvb, length - 4, 4, + proto_tree_add_text(atm_tree, tvb, length - 4, 4, "AAL5 CRC: 0x%08X (%s)", crc, (calc_crc == 0xC704DD7B) ? "correct" : "incorrect"); + } + next_tvb = tvb_new_subset(tvb, 0, aal5_length, aal5_length); } - next_tvb = tvb_new_subset(tvb, 0, aal5_length, aal5_length); } } |