Segfault in Tcptrace at trace.c:1215

[Ngiong]

Hello,
We are currently working on a new fuzz testing feature, and we found a crash in tcptrace.

Step to Reproduce
We configured and built libpcap-1.9.1 using CFLAGS="-g -O0" ./configure and make
and configured tcptrace using CFLAGS="-L${LIBPCAP_PATH}/lib -I${LIBPCAP_PATH}/include" LDFLAGS="-L${LIBPCAP_PATH}/lib -lpcap" ./configure and built using make, and run it with:

./tcptrace  --showtitle --continuous --nowarn_ooo --limit_conn_num <attached_file> -F -n --nores_addr 

Attachment: poc_0006.txt

Environment

• OS: Ubuntu 18.04.4 LTS
• Compiler: gcc 7.5.0
• tcptrace version: 6.6.7 (http://www.tcptrace.org/download/tcptrace-6.6.7.tar.gz)
• libpcap version: 1.9.1 (https://www.tcpdump.org/release/libpcap-1.9.1.tar.gz)

Additional context
Here's the stack trace: stack_trace_0006.txt

Program received signal SIGSEGV, Segmentation fault.
0x0000000000426102 in RemoveOldConns (conn_list_head=0x6cc900 <closed_conn_list_head>, conn_list_tail=0x6cc8f8 <closed_conn_list_tail>, expire_interval=480, num_conn_check=1 '\001', conn_count=0x6cc8f4 <closed_conn_count>) at trace.c:1215
1215	  if (((*conn_list_head)->ptp->last_time.tv_sec != 0) &&
#0  0x0000000000426102 in RemoveOldConns (conn_list_head=0x6cc900 <closed_conn_list_head>, conn_list_tail=0x6cc8f8 <closed_conn_list_tail>, expire_interval=480, num_conn_check=1 '\001', conn_count=0x6cc8f4 <closed_conn_count>) at trace.c:1215
#1  0x0000000000422f7a in UpdateConnLists (tcp_ptr=0x6fa1c0, ptcp=0x6e7cf4) at trace.c:1101
#2  0x0000000000420bdf in dotrace (pip=0x6e7ce0, ptcp=0x6e7cf4, plast=0x6e7d1b) at trace.c:2469
#3  0x0000000000417b7e in ProcessFile (filename=0x7fffffffe223 "input") at tcptrace.c:1167
#4  0x00000000004158ea in main (argc=4, argv=0x7fffffffde88) at tcptrace.c:785

Thank you.