dnn_backend_native: Add overflow check for length calculation.

We should not silently allocate an incorrect sized buffer.
Fixes trac issue #8718.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Reviewed-by: Guo, Yejun <yejun.guo@intel.com>

libavfilter/dnn/dnn_backend_native.c

@@ -79,6 +79,8 @@ static DNNReturnType set_input_output_native(void *model, DNNData *input, const
 
     av_freep(&oprd->data);
     oprd->length = calculate_operand_data_length(oprd);
+    if (oprd->length <= 0)
+        return DNN_ERROR;
     oprd->data = av_malloc(oprd->length);
     if (!oprd->data)
         return DNN_ERROR;
@@ -295,7 +297,13 @@ int32_t calculate_operand_dims_count(const DnnOperand *oprd)
 int32_t calculate_operand_data_length(const DnnOperand* oprd)
 {
     // currently, we just support DNN_FLOAT
-    return oprd->dims[0] * oprd->dims[1] * oprd->dims[2] * oprd->dims[3] * sizeof(float);
+    uint64_t len = sizeof(float);
+    for (int i = 0; i < 4; i++) {
+        len *= oprd->dims[i];
+        if (len > INT32_MAX)
+            return 0;
+    }
+    return len;
 }
 
 void ff_dnn_free_model_native(DNNModel **model)

libavfilter/dnn/dnn_backend_native.h

@@ -120,6 +120,8 @@ DNNReturnType ff_dnn_execute_model_native(const DNNModel *model, DNNData *output
 
 void ff_dnn_free_model_native(DNNModel **model);
 
+// NOTE: User must check for error (return value <= 0) to handle
+// case like integer overflow.
 int32_t calculate_operand_data_length(const DnnOperand *oprd);
 int32_t calculate_operand_dims_count(const DnnOperand *oprd);
 #endif

libavfilter/dnn/dnn_backend_native_layer_conv2d.c

@@ -113,6 +113,8 @@ int dnn_execute_layer_conv2d(DnnOperand *operands, const int32_t *input_operand_
     output_operand->dims[3] = conv_params->output_num;
     output_operand->data_type = operands[input_operand_index].data_type;
     output_operand->length = calculate_operand_data_length(output_operand);
+    if (output_operand->length <= 0)
+        return -1;
     output_operand->data = av_realloc(output_operand->data, output_operand->length);
     if (!output_operand->data)
         return -1;

libavfilter/dnn/dnn_backend_native_layer_depth2space.c

@@ -75,6 +75,8 @@ int dnn_execute_layer_depth2space(DnnOperand *operands, const int32_t *input_ope
     output_operand->dims[3] = new_channels;
     output_operand->data_type = operands[input_operand_index].data_type;
     output_operand->length = calculate_operand_data_length(output_operand);
+    if (output_operand->length <= 0)
+        return -1;
     output_operand->data = av_realloc(output_operand->data, output_operand->length);
     if (!output_operand->data)
         return -1;

libavfilter/dnn/dnn_backend_native_layer_mathbinary.c

@@ -91,6 +91,8 @@ int dnn_execute_layer_math_binary(DnnOperand *operands, const int32_t *input_ope
 
     output->data_type = input->data_type;
     output->length = calculate_operand_data_length(output);
+    if (output->length <= 0)
+        return DNN_ERROR;
     output->data = av_realloc(output->data, output->length);
     if (!output->data)
         return DNN_ERROR;

libavfilter/dnn/dnn_backend_native_layer_mathunary.c

@@ -65,6 +65,8 @@ int dnn_execute_layer_math_unary(DnnOperand *operands, const int32_t *input_oper
 
     output->data_type = input->data_type;
     output->length = calculate_operand_data_length(output);
+    if (output->length <= 0)
+        return DNN_ERROR;
     output->data = av_realloc(output->data, output->length);
     if (!output->data)
         return DNN_ERROR;

libavfilter/dnn/dnn_backend_native_layer_maximum.c

@@ -64,6 +64,8 @@ int dnn_execute_layer_maximum(DnnOperand *operands, const int32_t *input_operand
 
     output->data_type = input->data_type;
     output->length = calculate_operand_data_length(output);
+    if (output->length <= 0)
+        return DNN_ERROR;
     output->data = av_realloc(output->data, output->length);
     if (!output->data)
         return DNN_ERROR;

libavfilter/dnn/dnn_backend_native_layer_pad.c

@@ -111,6 +111,8 @@ int dnn_execute_layer_pad(DnnOperand *operands, const int32_t *input_operand_ind
     output_operand->dims[3] = new_channel;
     output_operand->data_type = operands[input_operand_index].data_type;
     output_operand->length = calculate_operand_data_length(output_operand);
+    if (output_operand->length <= 0)
+        return -1;
     output_operand->data = av_realloc(output_operand->data, output_operand->length);
     if (!output_operand->data)
         return -1;