global buffer overflow in printMP3Headers

[bestshow]

On libming latest version, a global buffer overflow was found in function printMP3Headers.

#listmp3 $FILE
global-buffer-overflow on address 0x00000074ad3c at pc 0x000000515d76 bp 0x7ffd9e6b9250 sp 0x7ffd9e6b9248
READ of size 4 at 0x00000074ad3c thread T0
    #0 0x515d75 in printMP3Headers /usr/include/bits/stdio.h:81:25
    #1 0x515f03 in main /home/haojun/Downloads/libming-master/util/listmp3.c:209:3
    #2 0x7f1d4bd07b34 in __libc_start_main /usr/src/debug/glibc-2.17-c758a686/csu/../csu/libc-start.c:274
    #3 0x41ab8b in _start (/home/haojun/Downloads/libming-afl-build/bin/listmp3+0x41ab8b)

0x00000074ad3c is located 36 bytes to the left of global variable 'mp2l23_bitrate_table' defined in 'listmp3.c:37:5' (0x74ad60) of size 60
0x00000074ad3c is located 0 bytes to the right of global variable 'mp2l1_bitrate_table' defined in 'listmp3.c:34:5' (0x74ad00) of size 60
global-buffer-overflow /usr/include/bits/stdio.h:81:25 in printMP3Headers
Shadow bytes around the buggy address:
  0x0000800e1550: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0000800e1560: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0000800e1570: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0000800e1580: 00 00 00 04 f9 f9 f9 f9 00 00 00 00 00 00 00 04
  0x0000800e1590: f9 f9 f9 f9 00 00 00 00 00 00 00 04 f9 f9 f9 f9
=>0x0000800e15a0: 00 00 00 00 00 00 00[04]f9 f9 f9 f9 00 00 00 00
  0x0000800e15b0: 00 00 00 04 f9 f9 f9 f9 00 04 f9 f9 f9 f9 f9 f9
  0x0000800e15c0: 00 04 f9 f9 f9 f9 f9 f9 00 04 f9 f9 f9 f9 f9 f9
  0x0000800e15d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0000800e15e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0000800e15f0: 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
==24629==ABORTING

testcase : https://github.com/bestshow/p0cs/blob/master/global-buffer-overflow_in_printMP3Headers
Credit : ADLab of Venustech

[hlef]

Successfully reproduced vulnerability on latest master.

As far as I am aware, this issue wasn't assigned a CVE id. I'll request one.

[hlef]

For the record, this issue was assigned identifier CVE-2017-16898.

[hlef]

$ hexdump global-buffer-overflow_in_printMP3Headers
0000000 e6ff fff8 ffff 007f
0000008

Third byte = 1111 1000, so it looks like this MP3 header is declaring a bitrate n°15 which is not a valid value. Unfortunately printMP3Headers doesn't handle this special case and calls bitrate = mp2l23_bitrate_table[bitrate_idx]; with bitrate_idx = 15, but the array has only 15 entries. This explains the buffer overflow.

I'll submit a PR once we're done with #96.