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Add another sanity check - there shouldn't be more than 47 bytes of 

padding before the AAL5 trailer.

svn path=/trunk/; revision=7308
This commit is contained in:
Guy Harris 2003-03-07 03:19:50 +00:00
parent d7bcd8e261
commit d63f5fdae3
1 changed files with 32 additions and 15 deletions
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47
packet-atm.c
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@ -1,7 +1,7 @@
/* packet-atm.c
* Routines for ATM packet disassembly
*
* $Id: packet-atm.c,v 1.63 2003/03/04 08:20:36 guy Exp $
* $Id: packet-atm.c,v 1.64 2003/03/07 03:19:50 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
@ -1018,29 +1018,46 @@ dissect_reassembled_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
* and must be less than the amount of space left after
* we remove the trailer.
*
* If it's not same, assume we don't have a trailer.
* If it's not sane, assume we don't have a trailer.
*/
if (aal5_length > 0 && aal5_length <= length - 8) {
if (tree) {
pad_length = length - aal5_length - 8;
if (pad_length > 0) {
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",
/*
* How much padding is there?
*/
pad_length = length - aal5_length - 8;
/*
* There is no reason for more than 47 bytes of padding.
* The most padding you can have would be 7 bytes at the
* end of the next-to-last cell (8 bytes after the end of
* the data means you can fit the trailer in that cell),
* plus 40 bytes in the last cell (with the last 8 bytes
* being padding).
*
* If there's more than 47 bytes of padding, assume we don't
* have a trailer.
*/
if (pad_length <= 47) {
if (tree) {
if (pad_length > 0) {
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",
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);
}
}
}