Description:
zziplib is an intentionally lightweight library that offers the ability to easily extract data from files archived in a single zip file.
A fuzz on it discovered an a NULL pointer access.
The complete ASan output:
# unzzipcat $FILE
==22686==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc 0x7f6de98b259a bp 0x7ffddc25a080 sp 0x7ffddc259f98 T0)
==22686==The signal is caused by a READ memory access.
==22686==Hint: address points to the zero page.
#0 0x7f6de98b2599 in strlen /var/tmp/portage/sys-libs/glibc-2.22-r4/work/glibc-2.22/string/../sysdeps/x86_64/strlen.S:76
#1 0x7f6de989b7ab in _IO_puts /var/tmp/portage/sys-libs/glibc-2.22-r4/work/glibc-2.22/libio/ioputs.c:36
#2 0x509d73 in main /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/bins/unzzipcat.c:94:6
#3 0x7f6de985161f in __libc_start_main /var/tmp/portage/sys-libs/glibc-2.22-r4/work/glibc-2.22/csu/libc-start.c:289
#4 0x419848 in _init (/usr/bin/unzzipcat+0x419848)
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /var/tmp/portage/sys-libs/glibc-2.22-r4/work/glibc-2.22/string/../sysdeps/x86_64/strlen.S:76 in strlen
==22686==ABORTING
Affected version:
0.13.62
Fixed version:
N/A
Commit fix:
N/A
Credit:
This bug was discovered by Agostino Sarubbo of Gentoo.
CVE:
N/A
Reproducer:
https://github.com/asarubbo/poc/blob/master/00158-zziplib-nullptr-main
Timeline:
2017-01-17: bug discovered and poked upstream
2017-02-09: blog post about the issue
Note:
This bug was found with American Fuzzy Lop.
Permalink:
https://blogs.gentoo.org/ago/2017/02/09/zziplib-null-pointer-dereference-in-main-unzzipcat-c