[PATCH 1/6] ASoC: codecs: wcd937x-sdw: Correct Soundwire ports mask

[Krzysztof Kozlowski]

Device has up to WCD937X_MAX_TX_SWR_PORTS (or WCD937X_MAX_SWR_PORTS
for sink) number of ports and the array assigned to prop.src_dpn_prop
and prop.sink_dpn_prop has 0..WCD937X_MAX_TX_SWR_PORTS-1 elements.  On
the other hand, GENMASK(high, low) creates an inclusive mask between
<high, low>, so we need the mask from 0 up to WCD937X_MAX_TX_SWR_PORTS-1.

Theoretically, too wide mask could cause an out of bounds read in
sdw_get_slave_dpn_prop() in stream.c, however only in the case of buggy
driver, e.g. adding incorrect number of ports via
sdw_stream_add_slave().

Fixes: c99a515ff153 ("ASoC: codecs: wcd937x-sdw: add SoundWire driver")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>

---

Not adding Cc-stable because I don't think the issue can lead to real
out-of-bounds read.
---
 sound/soc/codecs/wcd937x-sdw.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/wcd937x-sdw.c b/sound/soc/codecs/wcd937x-sdw.c
index 3abc8041406a..0c33f7f3dc25 100644
--- a/sound/soc/codecs/wcd937x-sdw.c
+++ b/sound/soc/codecs/wcd937x-sdw.c
@@ -1049,7 +1049,7 @@ static int wcd9370_probe(struct sdw_slave *pdev,
 	pdev->prop.lane_control_support = true;
 	pdev->prop.simple_clk_stop_capable = true;
 	if (wcd->is_tx) {
-		pdev->prop.source_ports = GENMASK(WCD937X_MAX_TX_SWR_PORTS, 0);
+		pdev->prop.source_ports = GENMASK(WCD937X_MAX_TX_SWR_PORTS - 1, 0);
 		pdev->prop.src_dpn_prop = wcd937x_dpn_prop;
 		wcd->ch_info = &wcd937x_sdw_tx_ch_info[0];
 		pdev->prop.wake_capable = true;
@@ -1062,7 +1062,7 @@ static int wcd9370_probe(struct sdw_slave *pdev,
 		/* Start in cache-only until device is enumerated */
 		regcache_cache_only(wcd->regmap, true);
 	} else {
-		pdev->prop.sink_ports = GENMASK(WCD937X_MAX_SWR_PORTS, 0);
+		pdev->prop.sink_ports = GENMASK(WCD937X_MAX_SWR_PORTS - 1, 0);
 		pdev->prop.sink_dpn_prop = wcd937x_dpn_prop;
 		wcd->ch_info = &wcd937x_sdw_rx_ch_info[0];
 	}

-- 
2.43.0