[FFmpeg-cvslog] avcodec/cuviddec: fix null pointer dereference

[Zhao Zhili]

ffmpeg | branch: master | Zhao Zhili <zhilizhao at tencent.com> | Fri Jun 24 22:42:01 2022 +0800| [07bcedc232feeb9e30336624f4e9977d47ac43bc] | committer: Timo Rothenpieler

avcodec/cuviddec: fix null pointer dereference

It can happened on error path of cuvid_decode_init().

Signed-off-by: Timo Rothenpieler <timo at rothenpieler.org>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=07bcedc232feeb9e30336624f4e9977d47ac43bc
---

 libavcodec/cuviddec.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/libavcodec/cuviddec.c b/libavcodec/cuviddec.c
index 5f265b1c70..b544b3361d 100644
--- a/libavcodec/cuviddec.c
+++ b/libavcodec/cuviddec.c
@@ -655,21 +655,23 @@ error:
 static av_cold int cuvid_decode_end(AVCodecContext *avctx)
 {
     CuvidContext *ctx = avctx->priv_data;
-    AVHWDeviceContext *device_ctx = (AVHWDeviceContext *)ctx->hwdevice->data;
-    AVCUDADeviceContext *device_hwctx = device_ctx->hwctx;
-    CUcontext dummy, cuda_ctx = device_hwctx->cuda_ctx;
+    AVHWDeviceContext *device_ctx = ctx->hwdevice ? (AVHWDeviceContext *)ctx->hwdevice->data : NULL;
+    AVCUDADeviceContext *device_hwctx = device_ctx ? device_ctx->hwctx : NULL;
+    CUcontext dummy, cuda_ctx = device_hwctx ? device_hwctx->cuda_ctx : NULL;
 
     av_fifo_freep2(&ctx->frame_queue);
 
-    ctx->cudl->cuCtxPushCurrent(cuda_ctx);
+    if (cuda_ctx) {
+        ctx->cudl->cuCtxPushCurrent(cuda_ctx);
 
-    if (ctx->cuparser)
-        ctx->cvdl->cuvidDestroyVideoParser(ctx->cuparser);
+        if (ctx->cuparser)
+            ctx->cvdl->cuvidDestroyVideoParser(ctx->cuparser);
 
-    if (ctx->cudecoder)
-        ctx->cvdl->cuvidDestroyDecoder(ctx->cudecoder);
+        if (ctx->cudecoder)
+            ctx->cvdl->cuvidDestroyDecoder(ctx->cudecoder);
 
-    ctx->cudl->cuCtxPopCurrent(&dummy);
+        ctx->cudl->cuCtxPopCurrent(&dummy);
+    }
 
     ctx->cudl = NULL;