[PATCH v2 3/3] ASoC: codecs: wcd934x: add a sanity check in set channel map

[Srinivas Kandagatla]

set channel map can be passed with a channel maps, however if
the number of channels that are passed are more than the actual
supported channels then we would be accessing array out of bounds.

So add a sanity check to validate these numbers!

Fixes: a61f3b4f476e ("ASoC: wcd934x: add support to wcd9340/wcd9341 codec")
Reported-by: John Stultz <john.stultz at linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla at linaro.org>
---
Changes since v1:
	- make sure the wcd is not de-referenced without intialization

 sound/soc/codecs/wcd934x.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sound/soc/codecs/wcd934x.c b/sound/soc/codecs/wcd934x.c
index 40f682f5dab8..d18ae5e3ee80 100644
--- a/sound/soc/codecs/wcd934x.c
+++ b/sound/soc/codecs/wcd934x.c
@@ -1873,6 +1873,12 @@ static int wcd934x_set_channel_map(struct snd_soc_dai *dai,
 
 	wcd = snd_soc_component_get_drvdata(dai->component);
 
+	if (tx_num > WCD934X_TX_MAX || rx_num > WCD934X_RX_MAX) {
+		dev_err(wcd->dev, "Invalid tx %d or rx %d channel count\n",
+			tx_num, rx_num);
+		return -EINVAL;
+	}
+
 	if (!tx_slot || !rx_slot) {
 		dev_err(wcd->dev, "Invalid tx_slot=%p, rx_slot=%p\n",
 			tx_slot, rx_slot);
-- 
2.21.0