mt76: mt7915: fix hwmon temp sensor mem use-after-free

Without this change, garbage is seen in the hwmon name and sensors output
for mt7915 is garbled. It appears that the hwmon logic does not make a
copy of the incoming string, but instead just copies a char* and expects
it to never go away.

Fixes: 33fe9c639c13 ("mt76: mt7915: add thermal sensor device support")
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/init.c b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
index d87b151..30d51b6 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7915/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
@@ -160,9 +160,12 @@ static int mt7915_thermal_init(struct mt7915_phy *phy)
        struct wiphy *wiphy = phy->mt76->hw->wiphy;
        struct thermal_cooling_device *cdev;
        struct device *hwmon;
+       const char *name;
 
-       cdev = thermal_cooling_device_register(wiphy_name(wiphy), phy,
-                                              &mt7915_thermal_ops);
+       name = devm_kasprintf(&wiphy->dev, GFP_KERNEL, "mt7915_%s",
+                             wiphy_name(wiphy));
+
+       cdev = thermal_cooling_device_register(name, phy, &mt7915_thermal_ops);
        if (!IS_ERR(cdev)) {
                if (sysfs_create_link(&wiphy->dev.kobj, &cdev->device.kobj,
                                      "cooling_device") < 0)
@@ -174,8 +177,7 @@ static int mt7915_thermal_init(struct mt7915_phy *phy)
        if (!IS_REACHABLE(CONFIG_HWMON))
                return 0;
 
-       hwmon = devm_hwmon_device_register_with_groups(&wiphy->dev,
-                                                      wiphy_name(wiphy), phy,
+       hwmon = devm_hwmon_device_register_with_groups(&wiphy->dev, name, phy,
                                                       mt7915_hwmon_groups);
        if (IS_ERR(hwmon))
                return PTR_ERR(hwmon);