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
==7574==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60300000ef9f at pc 0x7f98d2d1d3bf bp 0x7fff57e59e20 sp 0x7fff57e59e18
READ of size 1 at 0x60300000ef9f thread T0
#0 0x7f98d2d1d3be in __zzip_get32 /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/fetch.c:32:24
#1 0x7f98d2d1a9d9 in zzip_mem_entry_new /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/memdisk.c:224:34
#2 0x7f98d2d1a9d9 in zzip_mem_disk_load /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/memdisk.c:137
#3 0x7f98d2d198b7 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 0x7f98d1e5961f 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)
0x60300000ef9f is located 1 bytes to the right of 30-byte region [0x60300000ef80,0x60300000ef9e)
allocated by thread T0 here:
#0 0x4d2508 in malloc /tmp/portage/sys-devel/llvm-3.9.0-r1/work/llvm-3.9.0.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:64
#1 0x7f98d2d1a260 in zzip_mem_entry_new /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/memdisk.c:208:25
#2 0x7f98d2d1a260 in zzip_mem_disk_load /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/memdisk.c:137
#3 0x7f98d2d198b7 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 0x7f98d1e5961f in __libc_start_main /var/tmp/portage/sys-libs/glibc-2.22-r4/work/glibc-2.22/csu/libc-start.c:289
SUMMARY: AddressSanitizer: heap-buffer-overflow /tmp/portage/dev-libs/zziplib-0.13.62-r1/work/zziplib-0.13.62/zzip/fetch.c:32:24 in __zzip_get32
Shadow bytes around the buggy address:
0x0c067fff9da0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff9db0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff9dc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff9dd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c067fff9de0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c067fff9df0: 00 00 00[06]fa fa 00 00 00 02 fa fa 00 00 00 fa
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
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
==7574==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-2017-5974
Reproducer:
https://github.com/asarubbo/poc/blob/master/00150-zziplib-heapoverflow-__zzip_get32
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_get32-fetch-c
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