linux-kernel - [PATCH 2/4] hwmon: (dell-smm) Move clamping of fan speed out of i8k_set

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250917181036.10972-3-W_Armin@gmx.de>
Date: Wed, 17 Sep 2025 20:10:34 +0200
From: Armin Wolf <W_Armin@....de>
To: pali@...nel.org
Cc: linux@...ck-us.net,
	linux-hwmon@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/4] hwmon: (dell-smm) Move clamping of fan speed out of i8k_set_fan()

Currently i8k_set_fan() clamps the fan speed before performing the
SMM call to ensure that the speed is not negative and not greater than
i8k_fan_max. This however is mostly unnecessary as the hwmon and
thermal interfaces alread ensure this. Only the legacy ioctl interface
does not ensure that the fan speed passed to i8k_set_fan() does meet
the above criteria.

Move the clamping out of i8k_set_fan() and into the legacy ioctl
handler to prepare for future changes.

Signed-off-by: Armin Wolf <W_Armin@....de>
---
 drivers/hwmon/dell-smm-hwmon.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index 3f61b2d7935e..36576db09706 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -24,6 +24,7 @@
 #include <linux/init.h>
 #include <linux/kconfig.h>
 #include <linux/kernel.h>
+#include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
@@ -446,7 +447,6 @@ static int i8k_set_fan(const struct dell_smm_data *data, u8 fan, int speed)
 	if (disallow_fan_support)
 		return -EINVAL;
 
-	speed = (speed < 0) ? 0 : ((speed > data->i8k_fan_max) ? data->i8k_fan_max : speed);
 	regs.ebx = fan | (speed << 8);
 
 	return dell_smm_call(data->ops, &regs);
@@ -637,6 +637,8 @@ static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
 		if (copy_from_user(&speed, argp + 1, sizeof(int)))
 			return -EFAULT;
 
+		speed = clamp_val(speed, 0, data->i8k_fan_max);
+
 		mutex_lock(&data->i8k_mutex);
 		err = i8k_set_fan(data, val, speed);
 		if (err < 0)
-- 
2.39.5