#482 layer3.c: stack-based buffer overflow in III_dequantize_sample

[Hugo Lefeuvre]

Hi,
Agostino Sarubbo ago@gentoo.org published informations about the following security issue on his website, some weeks ago:

# lame -f -V 9 $FILE out.wav
==30801==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffe82a515a0 at pc 0x7f56d24c9df7 bp 0x7ffe82a4ffb0 sp 0x7ffe82a4ffa8
WRITE of size 4 at 0x7ffe82a515a0 thread T0
    #0 0x7f56d24c9df6 in III_dequantize_sample /var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/layer3.c
    #1 0x7f56d24a664f in decode_layer3_frame /var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/layer3.c:1738:17
    #2 0x7f56d24733ca in decodeMP3_clipchoice /var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/interface.c:615:13
    #3 0x7f56d2470c13 in decodeMP3 /var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/interface.c:696:12
    #4 0x7f56d2431092 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 0x7f56d243694a 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 0x7f56d243694a 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 0x7f56d1029680 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)

Address 0x7ffe82a515a0 is located in stack of thread T0 at offset 5024 in frame
    #0 0x7f56d24a548f in decode_layer3_frame /var/tmp/portage/media-sound/lame-3.99.5-r1/work/lame-3.99.5/mpglib/layer3.c:1659

  This frame has 4 object(s):
    [32, 344) 'scalefacs'
    [416, 5024) 'hybridIn' 0x1000505422b0: 00 00 00 00[f2]f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2
  0x1000505422c0: f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2
  0x1000505422d0: f2 f2 f2 f2 00 00 00 00 00 00 00 00 00 00 00 00
  0x1000505422e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1000505422f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x100050542300: 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
==30801==ABORTING

blog post: https://blogs.gentoo.org/ago/2017/06/17/lame-global-buffer-overflow-in-iii_i_stereo-layer3-c/

As member of the Debian LTS team, I'd like to fix this issue in our lame package, but I have difficulties reproducing it. Are you aware of this vulnerability ? Is a fix planned for 3.100 ?

Best Regards,
Hugo

[Hugo Lefeuvre]

Blog post is https://blogs.gentoo.org/ago/2017/06/17/lame-stack-based-buffer-overflow-in-iii_dequantize_sample-layer3-c/

[Robert Hegemann]

This is already fixed in CVS, look under closed bugs.

[Hugo Lefeuvre]

Same as #481, can you make sure that this issue is identical to #467 ? The asan output isn't exactly identical and I since I cannot reproduce these issues, I prefer to consider them different by default.

[Henri Salo]

You should consider it fixed unless you can't reproduce the issue. If you are not manually reproducing these issues please do not open up new issues in the upstream bug tracker.

[Hugo Lefeuvre]

This is not the way we handle issues in the Debian LTS team.

When I can't reproduce a vulnerability, I consider it undetermined as long as I can't prove it isn't affected. When trustworthy people claim to be able to reproduce the issue with the same version as me, I usually consider the package affected and try to reproduce and fix the vulnerability.

I opened these bugs because I couldn't find any sign showing that the lame dev team was aware of these cves. If you fix vulnerabilities in your cvs without any communication about it on your website/bug tracker, how do you want distros to be aware of your patch so they can update their packages ?