From 9885284c2259847b0d2b34b5574e3276607e37e4 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 10 Mar 2010 09:55:03 +0000 Subject: [PATCH] Check level_prefix a bit (this just checks the max our bitreader can handle, as i did nt find a limit in the spec) This should stop cavlc_decode_residual() on a zero bitstream Originally committed as revision 22429 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/h264_cavlc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/libavcodec/h264_cavlc.c b/libavcodec/h264_cavlc.c index ef92218b4..7da645dcd 100644 --- a/libavcodec/h264_cavlc.c +++ b/libavcodec/h264_cavlc.c @@ -431,8 +431,13 @@ static int decode_residual(H264Context *h, GetBitContext *gb, DCTELEM *block, in level_code= prefix + get_bits(gb, 4); //part }else{ level_code= 30 + get_bits(gb, prefix-3); //part - if(prefix>=16) + if(prefix>=16){ + if(prefix > 25+3){ + av_log(h->s.avctx, AV_LOG_ERROR, "Invalid level prefix\n"); + return -1; + } level_code += (1<<(prefix-3))-4096; + } } if(trailing_ones < 3) level_code += 2; -- 2.11.0