[FFmpeg-cvslog] avcodec/wmaprodec: Fix buflen computation in save_bits()

[Michael Niedermayer]

ffmpeg | branch: release/3.4 | Michael Niedermayer <michael at niedermayer.cc> | Fri Nov  8 19:20:31 2019 +0100| [f4daf42c1a5ce6ecf7234d804952536160870dba] | committer: Michael Niedermayer

avcodec/wmaprodec: Fix buflen computation in save_bits()

Fixes: Assertion failure
Fixes: 18630/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMAPRO_fuzzer-5201588654440448

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 589cb44498b5e9683c95746255a2abd6d1e74f94)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f4daf42c1a5ce6ecf7234d804952536160870dba
---

 libavcodec/wmaprodec.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavcodec/wmaprodec.c b/libavcodec/wmaprodec.c
index 8429c8dec6..4cff07adf8 100644
--- a/libavcodec/wmaprodec.c
+++ b/libavcodec/wmaprodec.c
@@ -1564,9 +1564,9 @@ static void save_bits(WMAProDecodeCtx *s, GetBitContext* gb, int len,
         s->frame_offset = get_bits_count(gb) & 7;
         s->num_saved_bits = s->frame_offset;
         init_put_bits(&s->pb, s->frame_data, MAX_FRAMESIZE);
-    }
-
-    buflen = (put_bits_count(&s->pb) + len + 8) >> 3;
+        buflen = (s->num_saved_bits      + len + 7) >> 3;
+    } else
+        buflen = (put_bits_count(&s->pb) + len + 7) >> 3;
 
     if (len <= 0 || buflen > MAX_FRAMESIZE) {
         avpriv_request_sample(s->avctx, "Too small input buffer");