mp3gain: stack-based buffer overflow in copy_mp (mpglibDBL/interface.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
==17667==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7f71080af610 at pc 0x7f710b824cfb bp 
0x7ffd67817fa0 sp 0x7ffd67817750
WRITE of size 72 at 0x7f71080af610 thread T0
    #0 0x7f710b824cfa  (/usr/lib/gcc/x86_64-pc-linux-gnu/6.4.0/libasan.so.3+0x5ccfa)
    #1 0x8a8ad0 in copy_mp /var/tmp/portage/media-sound/aacgain-1.9/work/aacgain-1.9/mp3gain/mpglibDBL/interface.c:188
    #2 0x8ac8bd in decodeMP3 /var/tmp/portage/media-sound/aacgain-1.9/work/aacgain-1.9/mp3gain/mpglibDBL/interface.c:685
    #3 0x43e767 in main /var/tmp/portage/media-sound/aacgain-1.9/work/aacgain-1.9/mp3gain/mp3gain.c:2262
    #4 0x7f710ab3d680 in __libc_start_main (/lib64/libc.so.6+0x20680)
    #5 0x4426c8 in _start (/usr/bin/aacgain+0x4426c8)

Address 0x7f71080af610 is located in stack of thread T0 at offset 50704 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' 0x0feea100dec0: 00 00[f4]f4 f3 f3 f3 f3 00 00 00 00 00 00 00 00
  0x0feea100ded0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0feea100dee0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0feea100def0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0feea100df00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0feea100df10: 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
==17667==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-2017-14411

Reproducer:
https://github.com/asarubbo/poc/blob/master/00348-aacgain-stackoverflow-copy_mp

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-copy_mp-mpglibdblinterface-c/

--
Agostino Sarubbo
Gentoo Linux Developer