From 562021e2fd4d74589905d9c566c686394d2b0526 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 4 Dec 2021 20:48:54 +0100 Subject: [PATCH] avformat/mov: Check next offset in mov_read_dref() Fixes: signed integer overflow: 9223372036200463215 + 1109914409 cannot be represented in type 'long' Fixes: 41480/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-6553086177443840 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavformat/mov.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/libavformat/mov.c b/libavformat/mov.c index 9ebfa0bcc7..2aed6e80ef 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -610,11 +610,13 @@ static int mov_read_dref(MOVContext *c, AVIOContext *pb, MOVAtom atom) for (i = 0; i < entries; i++) { MOVDref *dref = &sc->drefs[i]; uint32_t size = avio_rb32(pb); - int64_t next = avio_tell(pb) + size - 4; + int64_t next = avio_tell(pb); - if (size < 12) + if (size < 12 || next < 0 || next > INT64_MAX - size) return AVERROR_INVALIDDATA; + next += size - 4; + dref->type = avio_rl32(pb); avio_rb32(pb); // version + flags