[FFmpeg-cvslog] avcodec/fitsdec: Fix division by 0 in size check

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu Jun 13 16:08:03 2019 +0200| [07ffe94c172041cfb03109b9bb6b8bf577332bda] | committer: Michael Niedermayer

avcodec/fitsdec: Fix division by 0 in size check

Fixes: division by zero
Fixes: 15210/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FITS_fuzzer-5746033243455488

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=07ffe94c172041cfb03109b9bb6b8bf577332bda
---

 libavcodec/fitsdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/fitsdec.c b/libavcodec/fitsdec.c
index b0753813c9..67a8bd71f4 100644
--- a/libavcodec/fitsdec.c
+++ b/libavcodec/fitsdec.c
@@ -143,7 +143,7 @@ static int fits_read_header(AVCodecContext *avctx, const uint8_t **ptr, FITSHead
 
     size = abs(header->bitpix) >> 3;
     for (i = 0; i < header->naxis; i++) {
-        if (header->naxisn[i] > SIZE_MAX / size) {
+        if (size && header->naxisn[i] > SIZE_MAX / size) {
             av_log(avctx, AV_LOG_ERROR, "unsupported size of FITS image");
             return AVERROR_INVALIDDATA;
         }