[FFmpeg-devel] [PATCH 6/6] avformat/wavdec: Refuse to read chunks bigger than the filesize in w64_read_header()

Michael Niedermayer michael at niedermayer.cc
Sun Oct 18 01:08:42 EEST 2020


Fixes: OOM
Fixes: 26414/clusterfuzz-testcase-minimized-ffmpeg_dem_FWSE_fuzzer-5070632544632832

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

diff --git a/libavformat/wavdec.c b/libavformat/wavdec.c
index d6ab0dde35..31ec14e3d7 100644
--- a/libavformat/wavdec.c
+++ b/libavformat/wavdec.c
@@ -902,6 +902,7 @@ static int w64_read_header(AVFormatContext *s)
         } else if (!memcmp(guid, ff_w64_guid_summarylist, 16)) {
             int64_t start, end, cur;
             uint32_t count, chunk_size, i;
+            int64_t filesize  = avio_size(s->pb);
 
             start = avio_tell(pb);
             end = start + FFALIGN(size, INT64_C(8)) - 24;
@@ -916,7 +917,7 @@ static int w64_read_header(AVFormatContext *s)
                 chunk_key[4] = 0;
                 avio_read(pb, chunk_key, 4);
                 chunk_size = avio_rl32(pb);
-                if (chunk_size == UINT32_MAX)
+                if (chunk_size == UINT32_MAX || (filesize >= 0 && chunk_size > filesize))
                     return AVERROR_INVALIDDATA;
 
                 value = av_mallocz(chunk_size + 1);
-- 
2.17.1



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