From bdc4abd694a3234ef76d1f41a06e940d8fc9c0ed Mon Sep 17 00:00:00 2001 From: wm4 Date: Tue, 3 Feb 2015 19:04:12 +0100 Subject: [PATCH] avformat/mpc8: fix hang with fuzzed file This can lead to an endless loop by seeking back a few bytes after each attempted chunk read. Assuming negative sizes are always invalid, this is easy to fix. Other code in this demuxer treats negative sizes as invalid as well. Fixes ticket #4262. Signed-off-by: Michael Niedermayer (cherry picked from commit 56cc024220886927350cfc26ee695062ca7ecaf4) Signed-off-by: Michael Niedermayer --- libavformat/mpc8.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/libavformat/mpc8.c b/libavformat/mpc8.c index 73f805711d..916639fc52 100644 --- a/libavformat/mpc8.c +++ b/libavformat/mpc8.c @@ -216,6 +216,10 @@ static int mpc8_read_header(AVFormatContext *s) while(!url_feof(pb)){ pos = avio_tell(pb); mpc8_get_chunk_header(pb, &tag, &size); + if (size < 0) { + av_log(s, AV_LOG_ERROR, "Invalid chunk length\n"); + return AVERROR_INVALIDDATA; + } if(tag == TAG_STREAMHDR) break; mpc8_handle_chunk(s, tag, pos, size);