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List:       oss-security
Subject:    [oss-security] lame: global-buffer-overflow in II_step_one (layer2.c)
From:       "Agostino Sarubbo" <ago () gentoo ! org>
Date:       2017-06-28 12:04:54
Message-ID: 250758.429381193-sendEmail () localhost
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Description:
lame is a high quality MPEG Audio Layer III (MP3) encoder licensed under the LGPL.

Few notes before the details of this bug. Time ago a fuzz was done by Brian Carpenter and Jakub \
Wilk which posted the results on the debian  bugtracker. In cases like this, when upstream is \
not active and people do not post on the upstream bugzilla is easy discover duplicates, so I  \
downloaded all available testcases, and noone of the bug you will see on my blog is a duplicate \
of an existing issue. Upstream seems a bit  dead, latest release was into 2011, so this blog \
post will probably forwarded on the upstream bugtracker just for the record.

The complete ASan output of the issue:

# lame -f -V 9 $FILE out.wav
==27479==ERROR: AddressSanitizer: global-buffer-overflow on address 0x7f598d317f20 at pc \
0x7f598d2b246b bp 0x7ffe780cf310 sp 0x7ffe780cf308 READ of size 2 at 0x7f598d317f20 thread T0
    #0 0x7f598d2b246a in II_step_one \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/layer2.c:144:36  #1 \
0x7f598d2b246a in decode_layer2_frame \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/layer2.c:375  #2 \
0x7f598d29b377 in decodeMP3_clipchoice \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/interface.c:611:13  #3 \
0x7f598d298c13 in decodeMP3 \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/interface.c:696:12  #4 \
0x7f598d259092 in decode1_headersB_clipchoice \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/libmp3lame/mpglib_interface.c:149:11
  #5 0x7f598d25e94a in hip_decode1_headersB \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/libmp3lame/mpglib_interface.c:436:16
  #6 0x7f598d25e94a in hip_decode1_headers \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/libmp3lame/mpglib_interface.c:379  \
#7 0x51e984 in lame_decode_fromfile \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/frontend/get_audio.c:2089:11  #8 \
0x51e984 in read_samples_mp3 \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/frontend/get_audio.c:877  #9 \
0x51e984 in get_audio_common \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/frontend/get_audio.c:785  #10 \
0x51e4fa in get_audio \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/frontend/get_audio.c:688:16  #11 \
0x50f776 in lame_encoder_loop \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/frontend/lame_main.c:456:17  #12 \
0x50f776 in lame_encoder \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/frontend/lame_main.c:531  #13 \
0x50c43f in lame_main \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/frontend/lame_main.c:707:15  #14 \
0x510793 in c_main /var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/frontend/main.c:470:15
  #15 0x510793 in main \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/frontend/main.c:438  #16 \
0x7f598be51680 in __libc_start_main \
/tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289  #17 0x41c998 \
in _init (/usr/bin/lame+0x41c998)

0x7f598d317f20 is located 0 bytes to the right of global variable 'alloc_2' defined in 
'/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/l2tables.h:118:24' \
                (0x7f598d317de0) of size 320
SUMMARY: AddressSanitizer: global-buffer-overflow \
/var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/layer2.c:144:36 in  \
II_step_one Shadow bytes around the buggy address:
  0x0febb1a5af90: 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
  0x0febb1a5afa0: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
  0x0febb1a5afb0: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 00 00 00 00
  0x0febb1a5afc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0febb1a5afd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0febb1a5afe0: 00 00 00 00[f9]f9 f9 f9 f9 f9 f9 f9 00 00 00 00
  0x0febb1a5aff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0febb1a5b000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0febb1a5b010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0febb1a5b020: 00 00 00 00 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
  0x0febb1a5b030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  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
==27479==ABORTING

Affected version:
3.99.5

Fixed version:
N/A

Commit fix:
N/A

Credit:
This bug was discovered by Agostino Sarubbo of Gentoo.

CVE:
CVE-2017-9869

Reproducer:
https://github.com/asarubbo/poc/blob/master/00290-lame-globaloverflow-II_step_one

Timeline:
2017-06-01: bug discovered
2017-06-17: blog post about the issue
2017-06-25: CVE assigned

Note:
This bug was found with American Fuzzy Lop.

Permalink:
https://blogs.gentoo.org/ago/2017/06/17/lame-global-buffer-overflow-in-ii_step_one-layer2-c/

--
Agostino Sarubbo
Gentoo Linux Developer


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