Ethereal-dev: [ethereal-dev] SIGSEGV vb_decrement_usage_count (tvb=0x0, count=1) at tvbuff.c:2

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From: Florian Lohoff <flo@xxxxxxxxxx>
Date: Thu, 14 Sep 2000 14:58:59 +0200
Current CVS

This is GNU ethereal 0.8.12, compiled with GTK+ 1.2.7,
with libpcap 0.4a6, with libz 1.1.3, with UCD SNMP 4.1.1



(gdb) r
Starting program: /var/tmp/ethereal/ethereal/ethereal

Program received signal SIGSEGV, Segmentation fault.
tvb_decrement_usage_count (tvb=0x0, count=1) at tvbuff.c:250
250     if (tvb->usage_count <= count) {
(gdb) bt
#0  tvb_decrement_usage_count (tvb=0x0, count=1) at tvbuff.c:250
#1  0x80f44a2 in tvb_free (tvb=0x828b550) at tvbuff.c:209
#2  0x80f4449 in tvb_free_void (tvb=0x828b550) at tvbuff.c:186
#3  0x80e9d74 in do_throw (except=0xbfffdbac) at except.c:185
#4  0x80e9fa3 in except_throw (except_group=1, except_code=2,
    msg=0x8186140 "XCEPT_GROUP_ETHEREAL") at except.c:269
#5  0x80f48fb in check_offset_length (tvb=0x828b520, offset=14, length=74,
    offset_ptr=0x828b564, length_ptr=0x828b568) at tvbuff.c:428
#6  0x80f49bd in tvb_set_subset (tvb=0x828b550, backing=0x828b520,
    backing_offset=14, backing_length=74, reported_length=74) at tvbuff.c:450
#7  0x80f4a60 in tvb_new_subset (backing=0x828b520, backing_offset=14,
    backing_length=74, reported_length=74) at tvbuff.c:484
#8  0x8079595 in dissect_eth (tvb=0x828b520, pinfo=0x81d24a0, tree=0x0)
    at packet-eth.c:271
#9  0x80ebca7 in dissect_packet (pseudo_header=0x828d5dc,
    pd=0x82793d8 "\001@�\020?H", fd=0x82acbc0, tree=0x0) at packet.c:1055
#10 0x80f94bc in add_packet_to_packet_list (fdata=0x82acbc0, cf=0x81c2220,
    pseudo_header=0x828d5dc, buf=0x82793d8 "\001@�\020?H", refilter=1)
    at file.c:641

I dont think the easy fix of

if (tvbuff == NULL) 
	return(0);

is correct and only considered a workaround for a bug i am currently
unable to diagnose.

Packet triggering the problem attached ...

Flo
-- 
Florian Lohoff		flo@xxxxxxxxxx		      	+49-5201-669912
      "Write only memory - Oops. Time for my medication again ..."

Attachment: packet
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