[FFmpeg-trac] #1205(avcodec:open): Division by Zero in avcodec

[FFmpeg]

#1205: Division by Zero in avcodec
---------------------------------------+-----------------------------------
             Reporter:  daybreak       |                    Owner:
                 Type:  defect         |                   Status:  open
             Priority:  important      |                Component:  avcodec
              Version:  git-master     |               Resolution:
             Keywords:  crash fpe mkv  |               Blocked By:
             Blocking:                 |  Reproduced by developer:  1
Analyzed by developer:  0              |
---------------------------------------+-----------------------------------
Changes (by cehoyos):

 * keywords:   => crash fpe mkv
 * priority:  normal => important
 * version:  unspecified => git-master
 * status:  new => open
 * reproduced:  0 => 1


Comment:

 {{{
 (gdb) r -i 427535wmaproEOF.mkvtest54.mkv
 Starting program: ffmpeg_g -i 427535wmaproEOF.mkvtest54.mkv
 [Thread debugging using libthread_db enabled]
 [New Thread 0xb7b626c0 (LWP 11853)]
 ffmpeg version N-39787-gcca9528 Copyright (c) 2000-2012 the FFmpeg
 developers
   built on Apr 14 2012 08:48:33 with gcc 4.3.2
   configuration: --cc=/usr/local/gcc-4.3.2/bin/gcc --enable-gpl
   libavutil      51. 46.100 / 51. 46.100
   libavcodec     54. 14.101 / 54. 14.101
   libavformat    54.  3.100 / 54.  3.100
   libavdevice    53.  4.100 / 53.  4.100
   libavfilter     2. 69.101 /  2. 69.101
   libswscale      2.  1.100 /  2.  1.100
   libswresample   0. 11.100 /  0. 11.100
   libpostproc    52.  0.100 / 52.  0.100
 [matroska,webm @ 0x8ee3380] Unknown EBML doctype 'm-t?oska'
 [matroska,webm @ 0x8ee3380] Read error at pos. 377 (0x179)
 [matroska,webm @ 0x8ee3380] Unknown entry 0x81
 [matroska,webm @ 0x8ee3380] Unknown entry 0x2F62CE
 [matroska,webm @ 0x8ee3380] Unknown entry 0x81
 [matroska,webm @ 0x8ee3380] Unknown entry 0x7453
 [matroska,webm @ 0x8ee3380] Unknown entry 0x84
 [matroska,webm @ 0x8ee3380] Read error at pos. 377 (0x179)

 Program received signal SIGFPE, Arithmetic exception.
 [Switching to Thread 0xb7b626c0 (LWP 11853)]
 0x085f7e47 in decode_init (avctx=0x8eea240) at libavcodec/wmaprodec.c:402
 402                               / s->avctx->sample_rate + 2;
 (gdb) bt
 #0  0x085f7e47 in decode_init (avctx=0x8eea240) at
 libavcodec/wmaprodec.c:402
 #1  0x08572de5 in avcodec_open2 (avctx=0x8eea240, codec=Cannot access
 memory at address 0x4
 ) at libavcodec/utils.c:910
 #2  0x08194cd4 in avformat_find_stream_info (ic=0x8ee3380,
 options=0x8ee4180) at libavformat/utils.c:2448
 #3  0x08054733 in opt_input_file (o=0xbfc619f0, opt=0xbfc62270 "i",
     filename=0xbfc62272 "427535wmaproEOF.mkvtest54.mkv") at ffmpeg.c:3794
 #4  0x0805f9d2 in parse_option (optctx=0xbfc619f0, opt=0xbfc62270 "i",
     arg=0xbfc62272 "427535wmaproEOF.mkvtest54.mkv", options=0x87d96e0) at
 cmdutils.c:303
 #5  0x0805fd63 in parse_options (optctx=0xbfc619f0, argc=3,
 argv=0xbfc61c24, options=0x87d96e0,
     parse_arg_function=0x805a580 <opt_output_file>) at cmdutils.c:336
 #6  0x08059806 in main (argc=3, argv=0xbfc61c24) at ffmpeg.c:5255
 (gdb) disass $pc-32 $pc+32
 Dump of assembler code from 0x85f7e27 to 0x85f7e67:
 0x085f7e27 <decode_init+1605>:  imul   0x64(%esp),%edx
 0x085f7e2c <decode_init+1610>:  mov    %edx,0x44(%esp)
 0x085f7e30 <decode_init+1614>:  mov    0x68(%esp),%edx
 0x085f7e34 <decode_init+1618>:  mov    (%edx),%edx
 0x085f7e36 <decode_init+1620>:  mov    %edx,0x48(%esp)
 0x085f7e3a <decode_init+1624>:  mov    0x44(%esp),%edx
 0x085f7e3e <decode_init+1628>:  mov    0x48(%esp),%ebx
 0x085f7e42 <decode_init+1632>:  mov    %edx,%eax
 0x085f7e44 <decode_init+1634>:  sar    $0x1f,%edx
 0x085f7e47 <decode_init+1637>:  idivl  0x1b4(%ebx)
 0x085f7e4d <decode_init+1643>:  mov    %eax,%edx
 0x085f7e4f <decode_init+1645>:  add    $0x2,%edx
 0x085f7e52 <decode_init+1648>:  and    $0xfffffffc,%edx
 0x085f7e55 <decode_init+1651>:  cmp    %edx,0x40(%esp)
 0x085f7e59 <decode_init+1655>:  jge    0x85f7e75 <decode_init+1683>
 0x085f7e5b <decode_init+1657>:  mov    0x54(%esp),%ebx
 0x085f7e5f <decode_init+1661>:  lea    0x8778(%esi,%ebx,1),%eax
 0x085f7e66 <decode_init+1668>:  mov    0x68(%esp),%ebx
 End of assembler dump.
 (gdb) info register
 eax            0x19000  102400
 ecx            0x0      0
 edx            0x0      0
 ebx            0x8eea240        149856832
 esp            0xbfc613b0       0xbfc613b0
 ebp            0x0      0x0
 esi            0x1      1
 edi            0x0      0
 eip            0x85f7e47        0x85f7e47 <decode_init+1637>
 eflags         0x10246  [ PF ZF IF RF ]
 cs             0x73     115
 ss             0x7b     123
 ds             0x7b     123
 es             0x7b     123
 fs             0x0      0
 gs             0x33     51
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1205#comment:1>
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