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| author | Alex Converse <alex.converse@gmail.com> | 2012-02-09 20:21:47 -0800 |
|---|---|---|
| committer | Alex Converse <alex.converse@gmail.com> | 2012-02-10 09:57:39 -0800 |
| commit | 9e1db721c4329f4ac166a0bcc002c8d75f831aba (patch) | |
| tree | a43b63e8f04893c6e740865cbede6bc7915efdcc | |
| parent | b24aaabd44d68c6fafbfc476d1b70cc7ff8138ca (diff) | |
| download | ffmpeg-9e1db721c4329f4ac166a0bcc002c8d75f831aba.tar.gz | |
svq3: Prevent illegal reads while parsing extradata.
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
| -rw-r--r-- | libavcodec/svq3.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/libavcodec/svq3.c b/libavcodec/svq3.c index 5cc57a745d..eeb8ed7051 100644 --- a/libavcodec/svq3.c +++ b/libavcodec/svq3.c @@ -811,7 +811,9 @@ static av_cold int svq3_decode_init(AVCodecContext *avctx) MpegEncContext *s = &h->s; int m; unsigned char *extradata; + unsigned char *extradata_end; unsigned int size; + int marker_found = 0; if (ff_h264_decode_init(avctx) < 0) return -1; @@ -831,19 +833,26 @@ static av_cold int svq3_decode_init(AVCodecContext *avctx) /* prowl for the "SEQH" marker in the extradata */ extradata = (unsigned char *)avctx->extradata; - for (m = 0; m < avctx->extradata_size; m++) { - if (!memcmp(extradata, "SEQH", 4)) - break; - extradata++; + extradata_end = avctx->extradata + avctx->extradata_size; + if (extradata) { + for (m = 0; m + 8 < avctx->extradata_size; m++) { + if (!memcmp(extradata, "SEQH", 4)) { + marker_found = 1; + break; + } + extradata++; + } } /* if a match was found, parse the extra data */ - if (extradata && !memcmp(extradata, "SEQH", 4)) { + if (marker_found) { GetBitContext gb; int frame_size_code; size = AV_RB32(&extradata[4]); + if (size > extradata_end - extradata - 8) + return AVERROR_INVALIDDATA; init_get_bits(&gb, extradata + 8, size*8); /* 'frame size code' and optional 'width, height' */ |