[FFmpeg-cvslog] avcodec/exr: Check preview psize

[Michael Niedermayer]

ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Sat Sep 10 23:54:17 2022 +0200| [446de009f922014d77b801bb0a44ba6e3cc3aac4] | committer: Michael Niedermayer

avcodec/exr: Check preview psize

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>
(cherry picked from commit ac26712e35f5ebc726d1be14bb4a420949e66604)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=446de009f922014d77b801bb0a44ba6e3cc3aac4
---

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

diff --git a/libavcodec/exr.c b/libavcodec/exr.c
index 642a86ae6d..e3effad2e7 100644
--- a/libavcodec/exr.c
+++ b/libavcodec/exr.c
@@ -1947,9 +1947,12 @@ 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);