[FFmpeg-devel] [PATCH 6/7] lavf/flacenc: avoid buffer overread with unexpected extradata sizes

[Rodger Combs]

---
 libavformat/flacenc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/flacenc.c b/libavformat/flacenc.c
index 9768b6a..1906aee 100644
--- a/libavformat/flacenc.c
+++ b/libavformat/flacenc.c
@@ -322,7 +322,7 @@ static int flac_write_trailer(struct AVFormatContext *s)
     if (!c->write_header || !streaminfo)
         return 0;
 
-    if (pb->seekable & AVIO_SEEKABLE_NORMAL) {
+    if (pb->seekable & AVIO_SEEKABLE_NORMAL && (c->streaminfo || s->streams[0]->codecpar->extradata_size == FLAC_STREAMINFO_SIZE)) {
         /* rewrite the STREAMINFO header block data */
         file_size = avio_tell(pb);
         avio_seek(pb, 8, SEEK_SET);
-- 
2.6.4