[FFmpeg-cvslog] avcodec/jpeg2000: Check stepsize before using it

[Michael Niedermayer]

ffmpeg | branch: release/3.2 | Michael Niedermayer <michael at niedermayer.cc> | Tue Apr 16 00:41:54 2019 +0200| [485546eec10a13cbacd17901f02794952d621f20] | committer: Michael Niedermayer

avcodec/jpeg2000: Check stepsize before using it

Fixes: value 1.87633e+10 is outside the range of representable values of type 'int'
Fixes: Undefined behavior
Fixes: 14246/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5758393601490944

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 06ef186fa1b7329c6fe6723372a72464c998059b)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=485546eec10a13cbacd17901f02794952d621f20
---

 libavcodec/jpeg2000.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/jpeg2000.c b/libavcodec/jpeg2000.c
index afeb9df27c..afffaa7203 100644
--- a/libavcodec/jpeg2000.c
+++ b/libavcodec/jpeg2000.c
@@ -247,6 +247,11 @@ static void init_band_stepsize(AVCodecContext *avctx,
         }
     }
 
+    if (band->f_stepsize > (INT_MAX >> 15)) {
+        band->f_stepsize = 0;
+        av_log(avctx, AV_LOG_ERROR, "stepsize out of range\n");
+    }
+
     band->i_stepsize = band->f_stepsize * (1 << 15);
 
     /* FIXME: In OpenJPEG code stepsize = stepsize * 0.5. Why?