[FFmpeg-cvslog] lavfi/dnn: check the return value from sws_getContext

[Jun Zhao]

ffmpeg | branch: master | Jun Zhao <barryjzhao at tencent.com> | Wed Dec  9 17:53:10 2020 +0800| [0320dab265ef880b5b07cac1f9ebaa3fb5417f6a] | committer: Guo, Yejun

lavfi/dnn: check the return value from sws_getContext

sws_getContext may be return NULL, and it's will be dereferenced,
so add the check.

Signed-off-by: Jun Zhao <barryjzhao at tencent.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0320dab265ef880b5b07cac1f9ebaa3fb5417f6a
---

 libavfilter/dnn/dnn_io_proc.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/libavfilter/dnn/dnn_io_proc.c b/libavfilter/dnn/dnn_io_proc.c
index db13d7f5ce..c9b49be3bd 100644
--- a/libavfilter/dnn/dnn_io_proc.c
+++ b/libavfilter/dnn/dnn_io_proc.c
@@ -41,6 +41,13 @@ DNNReturnType proc_from_dnn_to_frame(AVFrame *frame, DNNData *output, void *log_
                                  frame->height,
                                  AV_PIX_FMT_GRAY8,
                                  0, NULL, NULL, NULL);
+        if (!sws_ctx) {
+            av_log(log_ctx, AV_LOG_ERROR, "Impossible to create scale context for the conversion "
+                "fmt:%s s:%dx%d -> fmt:%s s:%dx%d\n",
+                av_get_pix_fmt_name(AV_PIX_FMT_GRAYF32), frame->width * 3, frame->height,
+                av_get_pix_fmt_name(AV_PIX_FMT_GRAY8),   frame->width * 3, frame->height);
+            return DNN_ERROR;
+        }
         sws_scale(sws_ctx, (const uint8_t *[4]){(const uint8_t *)output->data, 0, 0, 0},
                            (const int[4]){frame->width * 3 * sizeof(float), 0, 0, 0}, 0, frame->height,
                            (uint8_t * const*)frame->data, frame->linesize);
@@ -64,6 +71,13 @@ DNNReturnType proc_from_dnn_to_frame(AVFrame *frame, DNNData *output, void *log_
                                  frame->height,
                                  AV_PIX_FMT_GRAY8,
                                  0, NULL, NULL, NULL);
+        if (!sws_ctx) {
+            av_log(log_ctx, AV_LOG_ERROR, "Impossible to create scale context for the conversion "
+                "fmt:%s s:%dx%d -> fmt:%s s:%dx%d\n",
+                av_get_pix_fmt_name(AV_PIX_FMT_GRAYF32), frame->width, frame->height,
+                av_get_pix_fmt_name(AV_PIX_FMT_GRAY8),   frame->width, frame->height);
+            return DNN_ERROR;
+        }
         sws_scale(sws_ctx, (const uint8_t *[4]){(const uint8_t *)output->data, 0, 0, 0},
                            (const int[4]){frame->width * sizeof(float), 0, 0, 0}, 0, frame->height,
                            (uint8_t * const*)frame->data, frame->linesize);
@@ -97,6 +111,13 @@ DNNReturnType proc_from_frame_to_dnn(AVFrame *frame, DNNData *input, void *log_c
                                  frame->height,
                                  AV_PIX_FMT_GRAYF32,
                                  0, NULL, NULL, NULL);
+        if (!sws_ctx) {
+            av_log(log_ctx, AV_LOG_ERROR, "Impossible to create scale context for the conversion "
+                "fmt:%s s:%dx%d -> fmt:%s s:%dx%d\n",
+                av_get_pix_fmt_name(AV_PIX_FMT_GRAY8),  frame->width * 3, frame->height,
+                av_get_pix_fmt_name(AV_PIX_FMT_GRAYF32),frame->width * 3, frame->height);
+            return DNN_ERROR;
+        }
         sws_scale(sws_ctx, (const uint8_t **)frame->data,
                            frame->linesize, 0, frame->height,
                            (uint8_t * const*)(&input->data),
@@ -121,6 +142,13 @@ DNNReturnType proc_from_frame_to_dnn(AVFrame *frame, DNNData *input, void *log_c
                                  frame->height,
                                  AV_PIX_FMT_GRAYF32,
                                  0, NULL, NULL, NULL);
+        if (!sws_ctx) {
+            av_log(log_ctx, AV_LOG_ERROR, "Impossible to create scale context for the conversion "
+                "fmt:%s s:%dx%d -> fmt:%s s:%dx%d\n",
+                av_get_pix_fmt_name(AV_PIX_FMT_GRAY8),  frame->width, frame->height,
+                av_get_pix_fmt_name(AV_PIX_FMT_GRAYF32),frame->width, frame->height);
+            return DNN_ERROR;
+        }
         sws_scale(sws_ctx, (const uint8_t **)frame->data,
                            frame->linesize, 0, frame->height,
                            (uint8_t * const*)(&input->data),