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Date: Thu, 6 Jun 2024 16:12:11 +0300
From: Dan Carpenter <dan.carpenter@linaro.org>
To: Thomas =?iso-8859-1?Q?Wei=DFschuh?= <linux@weissschuh.net>
Cc: Thomas =?iso-8859-1?Q?Wei=DFschuh?= <thomas@weissschuh.net>,
	Jean Delvare <jdelvare@suse.com>,
	Guenter Roeck <linux@roeck-us.net>,
	Benson Leung <bleung@chromium.org>,
	Tzung-Bi Shih <tzungbi@kernel.org>, chrome-platform@lists.linux.dev,
	linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: [PATCH] hwmon: (cros_ec) Prevent read overflow in probe()
Message-ID: <42331b70-bd3c-496c-8c79-3ec4faad40b8@moroto.mountain>
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The "resp.sensor_name" comes from cros_ec_cmd() and it hasn't necessarily
been NUL terminated.  We had not intended to read past "sensor_name_size"
bytes, however, there is a width vs precision bug in the format string.
The format needs to be precision '%.*s' instead of width '%*s'.
Precision prevents an out of bounds read, but width is a no-op.

Fixes: bc3e45258096 ("hwmon: add ChromeOS EC driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
 drivers/hwmon/cros_ec_hwmon.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/cros_ec_hwmon.c b/drivers/hwmon/cros_ec_hwmon.c
index 41f268fa8260..b3ba7247e06b 100644
--- a/drivers/hwmon/cros_ec_hwmon.c
+++ b/drivers/hwmon/cros_ec_hwmon.c
@@ -212,7 +212,7 @@ static void cros_ec_hwmon_probe_temp_sensors(struct device *dev, struct cros_ec_
 			continue;
 
 		sensor_name_size = strnlen(resp.sensor_name, sizeof(resp.sensor_name));
-		priv->temp_sensor_names[i] = devm_kasprintf(dev, GFP_KERNEL, "%*s",
+		priv->temp_sensor_names[i] = devm_kasprintf(dev, GFP_KERNEL, "%.*s",
 							    (int)sensor_name_size,
 							    resp.sensor_name);
 	}
-- 
2.43.0