Created attachment 1458982 [details]
poc to reproduce the crash

Description of problem:
There exists one null pointer deference bug in stradd in fileutil.c in catdoc0.95 which allows attacker to cause a denial-of-service via a crafted xls file.This bug can be triggered by the executable xls2csv.

Version-Release number of selected component (if applicable):
catdoc-0.95

How reproducible:
xls2csv $poc

Actual results:
ASan:
==38018==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f550749b746 bp 0x7ffd37a6f9c0 sp 0x7ffd37a6f158 T0)
    #0 0x7f550749b745 in strlen /build/glibc-Cl5G7W/glibc-2.23/string/../sysdeps/x86_64/strlen.S:76
    #1 0x436aac in __interceptor_strlen.part.45 asan_interceptors.cc.o
    #2 0x4f5447 in stradd /home/s2e/catdoc-0.95/src/fileutil.c:124
    #3 0x4f1287 in read_charset /home/s2e/catdoc-0.95/src/charsets.c:79
    #4 0x4edb6f in process_item /home/s2e/catdoc-0.95/src/xlsparse.c:159
    #5 0x4ed291 in do_table /home/s2e/catdoc-0.95/src/xlsparse.c:116
    #6 0x4eb211 in main /home/s2e/catdoc-0.95/src/xls2csv.c:167
    #7 0x7f550743082f in __libc_start_main /build/glibc-Cl5G7W/glibc-2.23/csu/../csu/libc-start.c:291
    #8 0x419048 in _start (/home/s2e/catdoc-0.95/src/xls2csv+0x419048)