[FFmpeg-devel] [PATCH 3/5] avcodec/exr: Check preview psize

[Michael Niedermayer]

Fixes: signed integer overflow: 17121181824 * 538976288 cannot be represented in type 'long long'
Fixes: 48798/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_EXR_fuzzer-5915330316206080

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/exr.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/libavcodec/exr.c b/libavcodec/exr.c
index 235f6fa6cdd..c924406f131 100644
--- a/libavcodec/exr.c
+++ b/libavcodec/exr.c
@@ -1942,9 +1942,12 @@ static int decode_header(EXRContext *s, AVFrame *frame)
                                                      "preview", 16)) >= 0) {
             uint32_t pw = bytestream2_get_le32(gb);
             uint32_t ph = bytestream2_get_le32(gb);
-            int64_t psize = 4LL * pw * ph;
+            uint64_t psize = pw * ph;
+            if (psize > INT64_MAX / 4)
+                return AVERROR_INVALIDDATA;
+            psize *= 4;
 
-            if (psize >= bytestream2_get_bytes_left(gb))
+            if ((int64_t)psize >= bytestream2_get_bytes_left(gb))
                 return AVERROR_INVALIDDATA;
 
             bytestream2_skip(gb, psize);
-- 
2.17.1