[PATCH][next] hwmon: (mlxreg-fan): Fix out of bounds read on array fan->pwm

From: Colin King <colin.king@canonical.com>
To: Jean Delvare <jdelvare@suse.com>,
	Guenter Roeck <linux@roeck-us.net>,
	Vadim Pasternak <vadimp@nvidia.com>,
	linux-hwmon@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH][next] hwmon: (mlxreg-fan): Fix out of bounds read on array fan->pwm
Date: Mon, 20 Sep 2021 19:09:21 +0100	[thread overview]
Message-ID: <20210920180921.16246-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

Array fan->pwm[] is MLXREG_FAN_MAX_PWM elements in size, however the
for-loop has a off-by-one error causing index i to be out of range
causing an out of bounds read on the array. Fix this by replacing
the <= operator with < in the for-loop.

Addresses-Coverity: ("Out-of-bounds read")
Fixes: 35edbaab3bbf ("hwmon: (mlxreg-fan) Extend driver to support multiply cooling devices")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/hwmon/mlxreg-fan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/mlxreg-fan.c b/drivers/hwmon/mlxreg-fan.c
index 35228ed112d7..feab9ec6a6ca 100644
--- a/drivers/hwmon/mlxreg-fan.c
+++ b/drivers/hwmon/mlxreg-fan.c
@@ -554,7 +554,7 @@ static int mlxreg_fan_cooling_config(struct device *dev, struct mlxreg_fan *fan)
 {
 	int i, j;
 
-	for (i = 0; i <= MLXREG_FAN_MAX_PWM; i++) {
+	for (i = 0; i < MLXREG_FAN_MAX_PWM; i++) {
 		struct mlxreg_fan_pwm *pwm = &fan->pwm[i];
 
 		if (!pwm->connected)
-- 
2.32.0

