[FFmpeg-devel] [PATCH 1/2] avcodec/diracdec: Check perspective_exp and zrs_exp.

[Ronald S. Bultje]

Hi,

On Aug 15, 2017 3:32 AM, "Michael Niedermayer" <michael at niedermayer.cc>
wrote:

Fixes: undefined shift
Fixes: runtime error: shift exponent 264 is too large for 32-bit type 'int'
Fixes: 2860/clusterfuzz-testcase-minimized-4672811689836544

Found-by: continuous fuzzing process https://github.com/google/oss-
fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/diracdec.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/diracdec.c b/libavcodec/diracdec.c
index f2837aca69..be8b282314 100644
--- a/libavcodec/diracdec.c
+++ b/libavcodec/diracdec.c
@@ -1161,6 +1161,11 @@ static int
dirac_unpack_prediction_parameters(DiracContext
*s)
                 s->globalmc[ref].perspective[0]  = dirac_get_se_golomb(gb);
                 s->globalmc[ref].perspective[1]  = dirac_get_se_golomb(gb);
             }
+            if (s->globalmc[ref].perspective_exp +
(uint64_t)s->globalmc[ref].zrs_exp > 30) {
+                av_log(s->avctx, AV_LOG_ERROR, "exp %d %d too large\n",
s->globalmc[ref].perspective_exp, s->globalmc[ref].zrs_exp);


This message is utterly unhelpful. Why is it there? Please don't waste
binary size with crap logs.

Ronald