From 92fde2585e98b83143e84fd2899148990f594c3f Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 17 Mar 2021 13:31:28 +0100 Subject: [PATCH] avformat/mov: Check offset addition for overflow Fixes: signed integer overflow: 9223372036854775807 + 536870912 cannot be represented in type 'long' Fixes: 31678/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-5614204619980800 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavformat/mov.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/libavformat/mov.c b/libavformat/mov.c index 97857789f4..f9c4dbe5d4 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -5051,6 +5051,7 @@ static int mov_read_sidx(MOVContext *c, AVIOContext *pb, MOVAtom atom) int64_t stream_size = avio_size(pb); int64_t offset = av_sat_add64(avio_tell(pb), atom.size), pts, timestamp; uint8_t version, is_complete; + int64_t offadd; unsigned i, j, track_id, item_count; AVStream *st = NULL; AVStream *ref_st = NULL; @@ -5088,11 +5089,15 @@ static int mov_read_sidx(MOVContext *c, AVIOContext *pb, MOVAtom atom) if (version == 0) { pts = avio_rb32(pb); - offset += avio_rb32(pb); + offadd= avio_rb32(pb); } else { pts = avio_rb64(pb); - offset += avio_rb64(pb); + offadd= avio_rb64(pb); } + if (av_sat_add64(offset, offadd) != offset + (uint64_t)offadd) + return AVERROR_INVALIDDATA; + + offset += (uint64_t)offadd; avio_rb16(pb); // reserved @@ -5115,6 +5120,8 @@ static int mov_read_sidx(MOVContext *c, AVIOContext *pb, MOVAtom atom) if (frag_stream_info) frag_stream_info->sidx_pts = timestamp; + if (av_sat_add64(offset, size) != offset + size) + return AVERROR_INVALIDDATA; offset += size; pts += duration; }