[PATCH v2] ASoC: SOF: ipc3-topology: Correct get_control_data for non bytes payload

[Peter Ujfalusi]

It is possible to craft a topology where sof_get_control_data() would do
out of bounds access because it expects that it is only called when the
payload is bytes type.
Confusingly it also handles other types of controls, but the payload
parsing implementation is only valid for bytes.

Fix the code to count the non bytes controls and instead of storing a
pointer to sof_abi_hdr in sof_widget_data (which is only valid for bytes),
store the pointer to the data itself and add a new member to save the size
of the data.

In case of non bytes controls we store the pointer to the chanv itself,
which is just an array of values at the end.

Reported-by: Sergey Senozhatsky <senozhatsky at chromium.org>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi at linux.intel.com>
---
Hi,

changes since v1:
- adjust the payload size for non bytes controls by subtracting the size of the
  sof_ipc_ctrl_data struct, plus add comment to note this

Regards,
Peter

 sound/soc/sof/ipc3-topology.c | 40 ++++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/sound/soc/sof/ipc3-topology.c b/sound/soc/sof/ipc3-topology.c
index 572bcbfdb356..f9f37e01edfa 100644
--- a/sound/soc/sof/ipc3-topology.c
+++ b/sound/soc/sof/ipc3-topology.c
@@ -20,7 +20,8 @@
 struct sof_widget_data {
 	int ctrl_type;
 	int ipc_cmd;
-	struct sof_abi_hdr *pdata;
+	void *pdata;
+	size_t pdata_size;
 	struct snd_sof_control *control;
 };
 
@@ -784,16 +785,29 @@ static int sof_get_control_data(struct snd_soc_component *scomp,
 		}
 
 		cdata = wdata[i].control->ipc_control_data;
-		wdata[i].pdata = cdata->data;
-		if (!wdata[i].pdata)
-			return -EINVAL;
 
 		/* make sure data is valid - data can be updated at runtime */
-		if (widget->dobj.widget.kcontrol_type[i] == SND_SOC_TPLG_TYPE_BYTES &&
-		    wdata[i].pdata->magic != SOF_ABI_MAGIC)
-			return -EINVAL;
+		if (widget->dobj.widget.kcontrol_type[i] == SND_SOC_TPLG_TYPE_BYTES) {
+			if (!cdata->data)
+				return -EINVAL;
+
+			if (cdata->data->magic != SOF_ABI_MAGIC)
+				return -EINVAL;
+
+			wdata[i].pdata = cdata->data->data;
+			wdata[i].pdata_size = cdata->data->size;
+		} else {
+			/* points to the control data union */
+			wdata[i].pdata = cdata->chanv;
+			/*
+			 * wdata[i].control->size is calculated with struct_size
+			 * and includes the size of struct sof_ipc_ctrl_data
+			 */
+			wdata[i].pdata_size = wdata[i].control->size -
+					      sizeof(struct sof_ipc_ctrl_data);
+		}
 
-		*size += wdata[i].pdata->size;
+		*size += wdata[i].pdata_size;
 
 		/* get data type */
 		switch (cdata->cmd) {
@@ -876,10 +890,12 @@ static int sof_process_load(struct snd_soc_component *scomp,
 	 */
 	if (ipc_data_size) {
 		for (i = 0; i < widget->num_kcontrols; i++) {
-			memcpy(&process->data[offset],
-			       wdata[i].pdata->data,
-			       wdata[i].pdata->size);
-			offset += wdata[i].pdata->size;
+			if (!wdata[i].pdata_size)
+				continue;
+
+			memcpy(&process->data[offset], wdata[i].pdata,
+			       wdata[i].pdata_size);
+			offset += wdata[i].pdata_size;
 		}
 	}
 
-- 
2.36.0