ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinha...@gmail.com> | Fri Aug 30 13:20:26 2019 +0200| [7c243eece3427bc5a6d54657d488d5c0c2985a8e] | committer: Andreas Rheinhardt
avformat/matroskadec: Sanitize SeekHead entries A Seek element in a Matroska SeekHead should contain a SeekID and a SeekPosition element and upon reading, they should be sanitized: Given that IDs are restricted to 32 bit, longer SeekIDs should be treated as invalid. Instead currently the lower 32 bits have been used. For SeekPosition, no checks were performed for the element to be present and if present, whether it was excessively large (i.e. the absolute file position described by it exceeding INT64_MAX). The SeekPosition element had a default value of -1 which means that a check seems to have been intended; but it was not implemented. This commit adds a check for overflow to the calculation of the absolute file position of the referenced level 1 elements. Using -1 (i.e. UINT64_MAX) as default value for SeekPosition implies that a Seek element without SeekPosition will run afoul of this check. Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@gmail.com> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=7c243eece3427bc5a6d54657d488d5c0c2985a8e --- libavformat/matroskadec.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c index 981fb4bc20..90de2e19d3 100644 --- a/libavformat/matroskadec.c +++ b/libavformat/matroskadec.c @@ -1866,8 +1866,12 @@ static void matroska_execute_seekhead(MatroskaDemuxContext *matroska) MatroskaSeekhead *seekheads = seekhead_list->elem; uint32_t id = seekheads[i].id; int64_t pos = seekheads[i].pos + matroska->segment_start; + MatroskaLevel1Element *elem; - MatroskaLevel1Element *elem = matroska_find_level1_elem(matroska, id); + if (id != seekheads[i].id || pos < matroska->segment_start) + continue; + + elem = matroska_find_level1_elem(matroska, id); if (!elem || elem->parsed) continue; _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
