diff options
| author | Denis Sergeev <denserg.edu@gmail.com> | 2025-12-09 09:37:06 +0300 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2025-12-14 09:34:38 -0800 |
| commit | 46c28bbbb150b80827e4bcbea231560af9d16854 (patch) | |
| tree | 262d2f294074745b37b985c922aa953bd27ea786 | |
| parent | 8f0b4cce4481fb22653697cced8d0d04027cb1e8 (diff) | |
hwmon: (dell-smm) Limit fan multiplier to avoid overflow
The fan nominal speed returned by SMM is limited to 16 bits, but the
driver allows the fan multiplier to be set via a module parameter.
Clamp the computed fan multiplier so that fan_nominal_speed *
i8k_fan_mult always fits into a signed 32-bit integer and refuse to
initialize the driver if the value is too large.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 20bdeebc88269 ("hwmon: (dell-smm) Introduce helper function for data init")
Signed-off-by: Denis Sergeev <denserg.edu@gmail.com>
Link: https://lore.kernel.org/r/20251209063706.49008-1-denserg.edu@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
| -rw-r--r-- | drivers/hwmon/dell-smm-hwmon.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c index a34753fc2973..6040a8940674 100644 --- a/drivers/hwmon/dell-smm-hwmon.c +++ b/drivers/hwmon/dell-smm-hwmon.c @@ -76,6 +76,9 @@ #define DELL_SMM_NO_TEMP 10 #define DELL_SMM_NO_FANS 4 +/* limit fan multiplier to avoid overflow */ +#define DELL_SMM_MAX_FAN_MULT (INT_MAX / U16_MAX) + struct smm_regs { unsigned int eax; unsigned int ebx; @@ -1253,6 +1256,12 @@ static int dell_smm_init_data(struct device *dev, const struct dell_smm_ops *ops data->ops = ops; /* All options must not be 0 */ data->i8k_fan_mult = fan_mult ? : I8K_FAN_MULT; + if (data->i8k_fan_mult > DELL_SMM_MAX_FAN_MULT) { + dev_err(dev, + "fan multiplier %u is too large (max %u)\n", + data->i8k_fan_mult, DELL_SMM_MAX_FAN_MULT); + return -EINVAL; + } data->i8k_fan_max = fan_max ? : I8K_FAN_HIGH; data->i8k_pwm_mult = DIV_ROUND_UP(255, data->i8k_fan_max); |