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Date: Thu, 01 Dec 2016 17:02:08 +0100
From: Agostino Sarubbo <ago@...too.org>
To: oss-security@...ts.openwall.com
Cc: cve-assign@...re.org
Subject: libming: listswf: heap-based buffer overflow in parseSWF_RGBA (parser.c)

If suitable for a CVE please assign one. Thanks.

Description:
libming is a Flash (SWF) output library. It can be used from PHP, Perl, Ruby, 
Python, C, C++, Java, and probably more on the way..

A fuzzing revealed an overflow in listswf. The bug does not reside in any 
shared object but if you have a web application that calls directly the 
listswf binary to parse untrusted swf, then you are affected.

The complete ASan output:

# listswf $FILE
header indicates a filesize of 237 but filesize is 191
File version: 6
File size: 191
Frame size: (3493,-4999)x(-5076,9541)
Frame rate: 39.625000 / sec.
Total frames: 33032
 Stream out of sync after parse of blocktype 18 (SWF_SOUNDSTREAMHEAD). 29 but 
expecting 27.

Offset: 21 (0x0015)
Block type: 18 (SWF_SOUNDSTREAMHEAD)
Block length: 4

  PlaybackSoundRate 5.5 kHz
  PlaybackSoundSize 16 bit
  PlaybackSoundType stereo
  StreamSoundCompression MP3
  StreamSoundRate 44 kHz
  StreamSoundSize error
  StreamSoundType mono
  StreamSoundSampleCount 10838
  LatencySeek 53805

Offset: 27 (0x001b)
Block type: 840 (Unknown Block Type)
Block length: 45


0000: 2c 37 a6 30 3a 29 ab d2  54 6e 8e 88 0a f5 1b 6a    ,7.0:).. Tn.....j
0010: a2 f7 a1 a3 a3 a1 e1 06  70 04 8e 90 82 03 40 47    ........ p.....@G
0020: e0 30 c6 a6 83 57 ac 46  4f 8a 91 76 07             .0...W.F O..v.



Offset: 74 (0x004a)
Block type: 514 (Unknown Block Type)
Block length: 27


0000: b2 05 12 c2 3e 3a 01 20  d8 a7 7d 63 01 11 5c fc    ....>:.  ..}c..\.
0010: 15 8e 90 43 8f 64 8e 58  49 ad 95                   ...C.d.X I..



Offset: 103 (0x0067)
Block type: 297 (Unknown Block Type)
Block length: 20


0000: 27 79 a2 e3 2c 56 2a 2d  d2 2c 37 a6 30 3a 29 ab    'y..,V*- .,7.0:).
0010: d2 54 6e 8e                                        .Tn.


skipping 8 bytes

Offset: 125 (0x007d)
Block type: 42 (SWF_DEFINETEXTFORMAT)
Block length: 8

255 gradients in SWF_MORPHGRADiENT, expected a max of 
8=================================================================
==31250==ERROR: AddressSanitizer: heap-buffer-overflow on address 
0x62400000df10 at pc 0x00000057f342 bp 0x7ffe24b21ef0 sp 0x7ffe24b21ee8
WRITE of size 1 at 0x62400000df10 thread T0
    #0 0x57f341 in parseSWF_RGBA /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/parser.c:66:12
    #1 0x57f341 in parseSWF_MORPHGRADIENTRECORD /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/parser.c:746
    #2 0x57f341 in parseSWF_MORPHGRADIENT /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/parser.c:761
    #3 0x57e25a in parseSWF_MORPHFILLSTYLE /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/parser.c:777:7
    #4 0x58b9b8 in parseSWF_MORPHFILLSTYLES /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/parser.c:804:7
    #5 0x58b9b8 in parseSWF_DEFINEMORPHSHAPE /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/parser.c:2098
    #6 0x5302cb in blockParse /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/blocktypes.c:145:14
    #7 0x527d4f in readMovie /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/main.c:265:11
    #8 0x527d4f in main /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/main.c:350
    #9 0x7f39cc7da61f in __libc_start_main /var/tmp/portage/sys-
libs/glibc-2.22-r4/work/glibc-2.22/csu/libc-start.c:289
    #10 0x419b38 in _init (/usr/bin/listswf+0x419b38)

0x62400000df10 is located 0 bytes to the right of 7696-byte region 
[0x62400000c100,0x62400000df10)
allocated by thread T0 here:
    #0 0x4d2af5 in calloc /tmp/portage/sys-devel/llvm-3.9.0-
r1/work/llvm-3.9.0.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:72
    #1 0x58b90a in parseSWF_MORPHFILLSTYLES /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/parser.c:801:28
    #2 0x58b90a in parseSWF_DEFINEMORPHSHAPE /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/parser.c:2098
    #3 0x5302cb in blockParse /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/blocktypes.c:145:14
    #4 0x527d4f in readMovie /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/main.c:265:11
    #5 0x527d4f in main /tmp/portage/media-
libs/ming-0.4.7/work/ming-0_4_7/util/main.c:350
    #6 0x7f39cc7da61f 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/media-
libs/ming-0.4.7/work/ming-0_4_7/util/parser.c:66:12 in parseSWF_RGBA
Shadow bytes around the buggy address:
  0x0c487fff9b90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c487fff9ba0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c487fff9bb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c487fff9bc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c487fff9bd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c487fff9be0: 00 00[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c487fff9bf0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c487fff9c00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c487fff9c10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c487fff9c20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c487fff9c30: 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
==31250==ABORTING

Affected version:
0.4.7

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/00076-libming-heapoverflow-parseSWF_RGBA

Timeline:
2016-11-24: bug discovered and reported to upstream
2016-12-01: blog post about the issue

Note:
This bug was found with American Fuzzy Lop.

Permalink:
https://blogs.gentoo.org/ago/2016/12/01/libming-listswf-heap-based-buffer-overflow-in-parseswf_rgba-parser-c

-- 
Agostino Sarubbo
Gentoo Linux Developer

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