ASoC: SOF: ipc: check ipc return value before data copy

[ Upstream commit 1919b42 ]

In tx_wait_done the ipc payload is copied before the DSP transaction
error code is checked. This might lead to corrupted data in kernel side
even though the error would be handled later. It is also pointless to
copy the data in case of error. So change the order of error check and
copy.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Jaska Uimonen <jaska.uimonen@linux.intel.com>
Link: https://lore.kernel.org/r/20200228231850.9226-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Jaska Uimonen

sound/soc/sof/ipc.c

@@ -215,15 +215,17 @@ static int tx_wait_done(struct snd_sof_ipc *ipc, struct snd_sof_ipc_msg *msg,
 		snd_sof_trace_notify_for_error(ipc->sdev);
 		ret = -ETIMEDOUT;
 	} else {
-		/* copy the data returned from DSP */
 		ret = msg->reply_error;
-		if (msg->reply_size)
-			memcpy(reply_data, msg->reply_data, msg->reply_size);
-		if (ret < 0)
+		if (ret < 0) {
 			dev_err(sdev->dev, "error: ipc error for 0x%x size %zu\n",
 				hdr->cmd, msg->reply_size);
-		else
+		} else {
 			ipc_log_header(sdev->dev, "ipc tx succeeded", hdr->cmd);
+			if (msg->reply_size)
+				/* copy the data returned from DSP */
+				memcpy(reply_data, msg->reply_data,
+				       msg->reply_size);
+		}
 	}
 
 	return ret;