drivers/ipc: validate pipe ioctl args

Author: Aphlita

components/drivers/ipc/pipe.c

@@ -193,9 +193,19 @@ static int pipe_fops_ioctl(struct dfs_file *fd, int cmd, void *args)
     switch ((rt_ubase_t)cmd)
     {
     case FIONREAD:
+        if (args == RT_NULL)
+        {
+            ret = -EINVAL;
+            break;
+        }
         *((int*)args) = rt_ringbuffer_data_len(pipe->fifo);
         break;
     case FIONWRITE:
+        if (args == RT_NULL)
+        {
+            ret = -EINVAL;
+            break;
+        }
         *((int*)args) = rt_ringbuffer_space_len(pipe->fifo);
         break;
     default: