mp3gain: stack-based buffer overflow in dct36 (mpglibDBL/layer3.c)

["Agostino Sarubbo" <ago () gentoo org>]

Description:
mp3gain is a program to analyze and adjust MP3 files to same volume.

The fuzz was done via the aacgain command-line tool which uses mp3gain which bundles an old-modified version of mpg123 
called mpglibDBL.
The upstream project seems to be dead, so the issue wasn’t communicated to them.

The complete ASan output of the issue:

# aacgain -f $FILE
==13869==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fa590d1b958 at pc 0x0000008b2341 bp 
0x7ffc23c02b70 sp 0x7ffc23c02b68
READ of size 8 at 0x7fa590d1b958 thread T0
    #0 0x8b2340 in dct36 /var/tmp/portage/media-sound/aacgain-1.9/work/aacgain-1.9/mp3gain/mpglibDBL/layer3.c:1279
    #1 0x8d26e6 in III_hybrid /var/tmp/portage/media-sound/aacgain-1.9/work/aacgain-1.9/mp3gain/mpglibDBL/layer3.c:1504
    #2 0x8d26e6 in do_layer3 /var/tmp/portage/media-sound/aacgain-1.9/work/aacgain-1.9/mp3gain/mpglibDBL/layer3.c:1695
    #3 0x8ac2f9 in decodeMP3 /var/tmp/portage/media-sound/aacgain-1.9/work/aacgain-1.9/mp3gain/mpglibDBL/interface.c:643
    #4 0x43e767 in main /var/tmp/portage/media-sound/aacgain-1.9/work/aacgain-1.9/mp3gain/mp3gain.c:2262
    #5 0x7fa5937b1680 in __libc_start_main (/lib64/libc.so.6+0x20680)
    #6 0x4426c8 in _start (/usr/bin/aacgain+0x4426c8)

Address 0x7fa590d1b958 is located in stack of thread T0 at offset 18776 in frame
    #0 0x4341ff in main /var/tmp/portage/media-sound/aacgain-1.9/work/aacgain-1.9/mp3gain/mp3gain.c:1411

  This frame has 7 object(s):
    [32, 33) 'maxgain'
    [96, 97) 'mingain'
    [160, 164) 'nprocsamp'
    [224, 232) 'maxsample'
    [288, 9504) 'lsamples'
    [9536, 18752) 'rsamples'
    [18784, 50704) 'mp' 0x0ff53219b720: 00 00 00 00 00 00 00 00 f2 f2 f2[f2]00 00 00 00
  0x0ff53219b730: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff53219b740: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff53219b750: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff53219b760: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff53219b770: 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
  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
==13869==ABORTING

Affected version:
1.5.2

Fixed version:
N/A

Commit fix:
N/A

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

CVE:
CVE-2017-14408

Reproducer:
https://github.com/asarubbo/poc/blob/master/00351-aacgain-stackoverflow-dct36

Timeline:
2017-08-28: bug discovered
2017-09-08: blog post about the issue
2017-09-13: CVE Assigned

Note:
This bug was found with American Fuzzy Lop.
This bug was identified with bare metal servers donated by Packet. This work is also supported by the Core 
Infrastructure Initiative.

Permalink:
https://blogs.gentoo.org/ago/2017/09/08/mp3gain-stack-based-buffer-overflow-in-dct36-mpglibdbllayer3-c/

--
Agostino Sarubbo
Gentoo Linux Developer