avcodec/shorten: Sanity check nmeans
authorMichael Niedermayer <michael@niedermayer.cc>
Tue, 5 Jun 2018 11:03:48 +0000 (13:03 +0200)
committerMichael Niedermayer <michael@niedermayer.cc>
Sun, 17 Jun 2018 23:16:04 +0000 (01:16 +0200)
Fixes: OOM
Fixes: 8195/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SHORTEN_fuzzer-5179785826271232

The reference software appears to use longs for 32bits and it uses int for nmeans
hinting that the intended maximum size was not 32bit.

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit d91a0b503d7a886587281bc1ee42476aa5e89f85)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
libavcodec/shorten.c

index ae0cdfe..8aeacfe 100644 (file)
@@ -450,6 +450,10 @@ static int read_header(ShortenContext *s)
             return AVERROR_INVALIDDATA;
         }
         s->nmean = get_uint(s, 0);
+        if (s->nmean > 32768U) {
+            av_log(s->avctx, AV_LOG_ERROR, "nmean is: %d\n", s->nmean);
+            return AVERROR_INVALIDDATA;
+        }
 
         skip_bytes = get_uint(s, NSKIPSIZE);
         if ((unsigned)skip_bytes > get_bits_left(&s->gb)/8) {