[FFmpeg-devel] [PATCH] libavcodec/h264dec: avoid arithmetic on null pointers

[Jeremy Dorfman]

null pointer arithmetic is undefined behavior in C.
---
 libavcodec/h264dec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/h264dec.c b/libavcodec/h264dec.c
index 2d691731c5..ef698f2630 100644
--- a/libavcodec/h264dec.c
+++ b/libavcodec/h264dec.c
@@ -912,8 +912,8 @@ static int finalize_frame(H264Context *h, AVFrame *dst, H264Picture *out, int *g
             av_log(h->avctx, AV_LOG_DEBUG, "Duplicating field %d to fill missing\n", field);
 
             for (p = 0; p<4; p++) {
-                dst_data[p] = f->data[p] + (field^1)*f->linesize[p];
-                src_data[p] = f->data[p] +  field   *f->linesize[p];
+                dst_data[p] = f->data[p] ? f->data[p] + (field^1)*f->linesize[p] : NULL;
+                src_data[p] = f->data[p] ? f->data[p] +  field   *f->linesize[p] : NULL;
                 linesizes[p] = 2*f->linesize[p];
             }
 
-- 
2.40.0.rc0.216.gc4246ad0f0-goog