[FFmpeg-devel] [PATCH] avformat/dhav: Limit get_duration() iterations

Michael Niedermayer michael at niedermayer.cc
Sun Oct 17 17:09:09 EEST 2021


Fixes: Timeout
Fixes: 39971/clusterfuzz-testcase-minimized-ffmpeg_IO_DEMUXER_fuzzer-5756969890217984
Fixes: 39977/clusterfuzz-testcase-minimized-ffmpeg_dem_DHAV_fuzzer-5327123053674496

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/dhav.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/dhav.c b/libavformat/dhav.c
index b6bb25204c2..6c1cdde32c9 100644
--- a/libavformat/dhav.c
+++ b/libavformat/dhav.c
@@ -234,12 +234,13 @@ static int64_t get_duration(AVFormatContext *s)
     int64_t start_pos = avio_tell(s->pb);
     int64_t start = 0, end = 0;
     struct tm timeinfo;
+    int max_interations = 100000;
 
     if (!s->pb->seekable)
         return 0;
 
     avio_seek(s->pb, avio_size(s->pb) - 8, SEEK_SET);
-    while (avio_tell(s->pb) > 12) {
+    while (avio_tell(s->pb) > 12 && max_interations--) {
         if (avio_rl32(s->pb) == MKTAG('d','h','a','v')) {
             int seek_back = avio_rl32(s->pb);
 
-- 
2.17.1



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