[FFmpeg-devel] [PATCH 4/6] avformat/ifv: Check that total frames do not overflow
Michael Niedermayer
michael at niedermayer.cc
Sun Oct 18 01:08:40 EEST 2020
Fixes: Infinite loop
Fixes: 26392/clusterfuzz-testcase-minimized-ffmpeg_dem_GIF_fuzzer-5713658237419520
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
libavformat/ifv.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/libavformat/ifv.c b/libavformat/ifv.c
index f95e9b0e52..4e904fa828 100644
--- a/libavformat/ifv.c
+++ b/libavformat/ifv.c
@@ -210,6 +210,7 @@ static int ifv_read_packet(AVFormatContext *s, AVPacket *pkt)
}
if (!ev) {
+ uint64_t vframes, aframes;
if (ifv->is_audio_present && !ea) {
/*read new video and audio indexes*/
@@ -217,8 +218,12 @@ static int ifv_read_packet(AVFormatContext *s, AVPacket *pkt)
ifv->next_audio_index = ifv->total_aframes;
avio_skip(s->pb, 0x1c);
- ifv->total_vframes += avio_rl32(s->pb);
- ifv->total_aframes += avio_rl32(s->pb);
+ vframes = ifv->total_vframes + (uint64_t)avio_rl32(s->pb);
+ aframes = ifv->total_aframes + (uint64_t)avio_rl32(s->pb);
+ if (vframes > INT_MAX || aframes > INT_MAX)
+ return AVERROR_INVALIDDATA;
+ ifv->total_vframes = vframes;
+ ifv->total_aframes = aframes;
avio_skip(s->pb, 0xc);
if (avio_feof(s->pb))
@@ -240,7 +245,10 @@ static int ifv_read_packet(AVFormatContext *s, AVPacket *pkt)
ifv->next_video_index = ifv->total_vframes;
avio_skip(s->pb, 0x1c);
- ifv->total_vframes += avio_rl32(s->pb);
+ vframes = ifv->total_vframes + (uint64_t)avio_rl32(s->pb);
+ if (vframes > INT_MAX)
+ return AVERROR_INVALIDDATA;
+ ifv->total_vframes = vframes;
avio_skip(s->pb, 0x10);
if (avio_feof(s->pb))
--
2.17.1
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