From 28f303542e90bc34f96e2e04af6f1b9e9b9d65ab 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 7017c187f7..31026fef1c 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);