[Bug] NULL Pointer Dereference in ports2PORT at portmap.c:112

[bigben-plusplus]

Describe the bug
There is a NULL Pointer Dereference in ports2PORT when the user passes ill-formatted portmap string to tcprewrite with option -r or --portmap

To Reproduce
Steps to reproduce the behavior:

1. download tcpreplay-4.4.4 release and build

wget https://github.com/appneta/tcpreplay/releases/download/v4.4.4/tcpreplay-4.4.4.tar.xz
tar xJf tcpreplay-4.4.4.tar.xz && cd tcpreplay-4.4.4 && ./configure && make -j8 && make install

2. inject ill-formatted '--portmap PORT1s-PORT1e:PORT2' to tcprewrite, pragram crashes when PORT1e is absent

[root@b545adff9ebe dev]# tcpprep -c 172.17.0.1/32 -i in.pcap -o in.pcap.cache
[root@b545adff9ebe dev]# tcprewrite -r 1:2 -i in.pcap -c in.pcap.cache -o out.pcap
[root@b545adff9ebe dev]# tcprewrite -r 1-:2 -i in.pcap -c in.pcap.cache -o out.pcap
Segmentation fault (core dumped)
[root@b545adff9ebe dev]# 

PS: any valid in.pcap with the given --portmap string may reproduce the case.

Expected behavior
Program crashes with SEGV.

Screenshots

[root@b545adff9ebe dev]# gdb tcprewrite
GNU gdb (GDB) Red Hat Enterprise Linux 7.6.1-120.el7
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/local/bin/tcprewrite...done.
(gdb) r -r 1-:2 -i in.pcap -c in.pcap.cache -o out.pcap
Starting program: /usr/local/bin/tcprewrite -r 1-:2 -i in.pcap -c in.pcap.cache -o out.pcap
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff73e4fe7 in ____strtoll_l_internal () from /lib64/libc.so.6
Missing separate debuginfos, use: debuginfo-install glibc-2.17-326.el7_9.3.x86_64 libpcap-1.5.3-13.el7_9.x86_64
(gdb) bt
#0  0x00007ffff73e4fe7 in ____strtoll_l_internal () from /lib64/libc.so.6
#1  0x000000000040685e in ports2PORT (ports=<optimized out>) at portmap.c:112
#2  0x0000000000406c6c in parse_portmap (portmap=portmap@entry=0x633e68, 
    ourstr=<optimized out>) at portmap.c:191
#3  0x0000000000404618 in tcpedit_post_args (tcpedit=0x6335e0)
    at parse_args.c:184
#4  0x000000000040268c in main (argc=0, argv=<optimized out>)
    at tcprewrite.c:84
(gdb) info reg 
rax            0x7ffff776ff00	140737345158912
rbx            0x634810	6506512
rcx            0x0	0
rdx            0xa	10
rsi            0x7fffffffe588	140737488348552
rdi            0x0	0
rbp            0x0	0x0
rsp            0x7fffffffe520	0x7fffffffe520
r8             0x7ffff7772060	140737345167456
r9             0x6347f1	6506481
r10            0x1	1
r11            0x0	0
r12            0x1	1
r13            0x0	0
r14            0x2	2
r15            0x633010	6500368
rip            0x7ffff73e4fe7	0x7ffff73e4fe7 <____strtoll_l_internal+55>
eflags         0x10283	[ CF SF IF RF ]
cs             0x33	51
ss             0x2b	43
ds             0x0	0
es             0x0	0
fs             0x0	0
gs             0x0	0
(gdb) 

System (please complete the following information):

• OS: CentOS Linux release 7.9.2009 (Core)
• Tcpreplay Version: 4.4.4