Module: libav Branch: release/0.8 Commit: 7585a6254bbb38148e4467793fc34211b79d5f7d
Author: Vittorio Giovara <[email protected]> Committer: Vittorio Giovara <[email protected]> Date: Wed Jul 30 19:33:36 2014 +0100 h264: prevent theoretical infinite loop in SEI parsing Properly address CVE-2011-3946 and parse bitstream as described in the spec. CC: [email protected] Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind --- libavcodec/h264_sei.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/libavcodec/h264_sei.c b/libavcodec/h264_sei.c index 5995a8e..776ce57 100644 --- a/libavcodec/h264_sei.c +++ b/libavcodec/h264_sei.c @@ -165,17 +165,22 @@ int ff_h264_decode_sei(H264Context *h){ MpegEncContext * const s = &h->s; while (get_bits_left(&s->gb) > 16) { - int size, type; + int type = 0; + int size = 0; + int last = 0; - type=0; - do{ - type+= show_bits(&s->gb, 8); - }while(get_bits(&s->gb, 8) == 255); + while (get_bits_left(&s->gb) >= 8 && + (last = get_bits(&s->gb, 8)) == 255) { + type += 255; + } + type += last; - size=0; - do{ - size+= show_bits(&s->gb, 8); - }while(get_bits(&s->gb, 8) == 255); + last = 0; + while (get_bits_left(&s->gb) >= 8 && + (last = get_bits(&s->gb, 8)) == 255) { + size += 255; + } + size += last; if (size > get_bits_left(&s->gb) / 8) { av_log(s->avctx, AV_LOG_ERROR, "SEI type %d truncated at %d\n", _______________________________________________ libav-commits mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-commits
