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 heap overflow.
The complete ASan output:
# unzzipcat-mem $FILE ==7970==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60300000f2c8 at pc 0x7f59277fd153 bp 0x7fff136e1e30 sp 0x7fff136e1e28 READ of size 2 at 0x60300000f2c8 thread T0 #0 0x7f59277fd152 in zzip_mem_entry_extra_block /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/memdisk.c:248:20 #1 0x7f59277fd152 in zzip_mem_entry_new /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/memdisk.c:218 #2 0x7f59277fd152 in zzip_mem_disk_load /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/memdisk.c:137 #3 0x7f59277fb8b7 in zzip_mem_disk_open /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/memdisk.c:89:5 #4 0x50982d in main /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/bins/unzzipcat-mem.c:82:12 #5 0x7f592693b61f in __libc_start_main /var/tmp/portage/sys-libs/glibc-2.22-r4/work/glibc-2.22/csu/libc-start.c:289 #6 0x419748 in _init (/usr/bin/unzzipcat-mem+0x419748) AddressSanitizer can not describe address in more detail (wild memory access suspected). SUMMARY: AddressSanitizer: heap-buffer-overflow /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/memdisk.c:248:20 in zzip_mem_entry_extra_block Shadow bytes around the buggy address: 0x0c067fff9e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff9e10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff9e20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff9e30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff9e40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa =>0x0c067fff9e50: fa fa fa fa fa fa fa fa fa[fa]fa fa fa fa fa fa 0x0c067fff9e60: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff9e70: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff9e80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff9e90: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c067fff9ea0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Heap right redzone: fb Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack partial redzone: f4 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb ==7970==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:
CVE-2017-5976
Reproducer:
https://github.com/asarubbo/poc/blob/master/00152-zziplib-heapoverflow-zzip_mem_entry_extra_block
Timeline:
2017-01-17: bug discovered and poked upstream
2017-02-09: blog post about the issue
2017-02-13: CVE assigned
Note:
This bug was found with American Fuzzy Lop.
Permalink:
https://blogs.gentoo.org/ago/2017/02/09/zziplib-heap-based-buffer-overflow-in-zzip_mem_entry_extra_block-memdisk-c
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