[FFmpeg-trac] #764(avcodec:new): Increasing robustness of runlength decoding for scantable access in mpeg12.c

FFmpeg trac at avcodec.org
Thu Dec 15 19:50:36 CET 2011


#764: Increasing robustness of runlength decoding for scantable access in
mpeg12.c
-------------------------------------+-------------------------------------
             Reporter:  erik         |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:  avcodec
              Version:  unspecified  |               Resolution:
             Keywords:  mpeg         |               Blocked By:
  robustness                         |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------

Comment (by erik):

 Yes, but it is somewhere in a 4 GByte recording. Crashing depends on OS
 and memory allocation so I had great difficulty to get a reproducable
 crash, any change of code or code ordering can make it disappear and come
 back randomly in other corrupted recordings.
 Libmpeg2 has a similar robustness precaution. There it is better
 implemented. They explicitly check on values <0 or >= 64 and have a
 fallback in case the runlength decoding is corrupt. My proposal is rude
 but simple.

 On posting on ffmpeg-devel. I hesitate to claim the status to be able to
 contribute there.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/764#comment:2>
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