[FFmpeg-devel] [PATCH 1/4] avformat/matroskadec: Check for EOF in resync loop

Michael Niedermayer michael at niedermayer.cc
Sat Jan 30 17:00:18 EET 2021


Fixes: Timeout (too long -> instantly)
Fixes: 29136/clusterfuzz-testcase-minimized-ffmpeg_dem_WEBM_DASH_MANIFEST_fuzzer-4586141227548672

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/matroskadec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 374831baa3..1f28108887 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -2895,6 +2895,8 @@ static int matroska_read_header(AVFormatContext *s)
             goto fail;
         pos = avio_tell(matroska->ctx->pb);
         res = ebml_parse(matroska, matroska_segment, matroska);
+        if (res == AVERROR(EIO)) // EOF is translated to EIO, this exists the loop on EOF
+            goto fail;
     }
     /* Set data_offset as it might be needed later by seek_frame_generic. */
     if (matroska->current_id == MATROSKA_ID_CLUSTER)
-- 
2.17.1



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