From 423a3b685f318d989842959d30088f49bd2124ff Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Mon, 17 Jan 2022 14:26:05 +0100 Subject: [PATCH] avformat/mov: Check size before subtraction Fixes: signed integer overflow: -9223372036854775808 - 8 cannot be represented in type 'long' Fixes: 43542/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-5237670148702208 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit d8d9d506a3de976b647bcbb8f76c7b8d30eff576) Signed-off-by: Michael Niedermayer --- libavformat/mov.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/libavformat/mov.c b/libavformat/mov.c index dfbd94dfc6..b266687656 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -6897,6 +6897,8 @@ static int mov_read_default(MOVContext *c, AVIOContext *pb, MOVAtom atom) if (a.size == 0) { a.size = atom.size - total_size + 8; } + if (a.size < 0) + break; a.size -= 8; if (a.size < 0) break;