[FFmpeg-devel] [PATCH 3/8] avcodec/dpx: Check elements in 12bps planar path

[Michael Niedermayer]

Fixes: null pointer dereference
Fixes: 8946/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DPX_fuzzer-5078915222601728

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/dpx.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/libavcodec/dpx.c b/libavcodec/dpx.c
index f75e2cbbca..cf23bb6ba1 100644
--- a/libavcodec/dpx.c
+++ b/libavcodec/dpx.c
@@ -395,12 +395,14 @@ static int decode_frame(AVCodecContext *avctx,
                     if (elements == 4)
                         *dst[3]++ = read16(&buf, endian) >> shift & 0xFFF;
                 } else {
-                    *dst[2]++ = read12in32(&buf, &rgbBuffer,
-                                           &n_datum, endian);
+                    if (elements >= 3)
+                        *dst[2]++ = read12in32(&buf, &rgbBuffer,
+                                               &n_datum, endian);
                     *dst[0]++ = read12in32(&buf, &rgbBuffer,
                                            &n_datum, endian);
-                    *dst[1]++ = read12in32(&buf, &rgbBuffer,
-                                           &n_datum, endian);
+                    if (elements >= 2)
+                        *dst[1]++ = read12in32(&buf, &rgbBuffer,
+                                               &n_datum, endian);
                     if (elements == 4)
                         *dst[3]++ = read12in32(&buf, &rgbBuffer,
                                                &n_datum, endian);
-- 
2.18.0