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Date: Thu, 09 Feb 2017 14:43:08 +0100
From: Agostino Sarubbo <ago@...too.org>
To: oss-security@...ts.openwall.com
Subject: zziplib: heap-based buffer overflow in zzip_mem_entry_extra_block (memdisk.c)
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:
N/A
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
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
--
Agostino Sarubbo
Gentoo Linux Developer
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