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

Colin Ian King · groeck · commit 000cc5bc49aa · 2021-10-12T07:22:38.000-07:00
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") Reported-by: Vadim Pasternak <vadimp@nvidia.com> Fixes: 35edbaa ("hwmon: (mlxreg-fan) Extend driver to support multiply cooling devices") Signed-off-by: Colin Ian King <colin.king@canonical.com> Link: https://lore.kernel.org/r/20210920180921.16246-1-colin.king@canonical.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
diff --git 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)

Original file line number	Diff line number	Diff line change
`@@ -554,7 +554,7 @@ static int mlxreg_fan_cooling_config(struct device dev, struct mlxreg_fan fan)`
`554`	`554`	`{`
`555`	`555`	`int i, j;`
`556`	`556`
`557`		`- for (i = 0; i <= MLXREG_FAN_MAX_PWM; i++) {`
	`557`	`+ for (i = 0; i < MLXREG_FAN_MAX_PWM; i++) {`
`558`	`558`	`struct mlxreg_fan_pwm *pwm = &fan->pwm[i];`
`559`	`559`
`560`	`560`	`if (!pwm->connected)`