diff options
| author | Kean Ren <rh_king@163.com> | 2026-05-21 11:52:28 +0800 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2026-05-21 06:48:19 -0700 |
| commit | e6056b1f5a38bbe57ccbbba2609efecbd87ae08c (patch) | |
| tree | 73b6e19432b8a38c805ef1d295949ee39607f0b0 | |
| parent | 6c4e001cb0567b81340270d8fc3d53e39435ae70 (diff) | |
hwmon: (lenovo-ec-sensors): Fix EC "MCHP" signature validation logic
The EC signature check uses && instead of || between the four
byte comparisons. With &&, the condition is true only when ALL
four bytes fail to match simultaneously, meaning the driver
accepts a device as a valid Microchip EC if ANY single byte of
the 4-byte "MCHP" signature happens to match.
Due to short-circuit evaluation, if the first byte reads back as
'M' (0x4D, a very common register value), the remaining three
comparisons are skipped entirely and the device is accepted.
Change && to || so the check rejects devices that do not fully
match the expected EC signature, as originally intended.
Fixes: 70118f85e6538 ("hwmon: Add EC Chip driver for Lenovo ThinkStation motherboards")
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Signed-off-by: Kean Ren <rh_king@163.com>
Link: https://lore.kernel.org/r/20260521035228.533317-3-rh_king@163.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
| -rw-r--r-- | drivers/hwmon/lenovo-ec-sensors.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/hwmon/lenovo-ec-sensors.c b/drivers/hwmon/lenovo-ec-sensors.c index a16cc5e4053a..24a182abf9a3 100644 --- a/drivers/hwmon/lenovo-ec-sensors.c +++ b/drivers/hwmon/lenovo-ec-sensors.c @@ -537,9 +537,9 @@ static int lenovo_ec_probe(struct platform_device *pdev) outw_p(MCHP_SING_IDX, MCHP_EMI0_EC_ADDRESS); mutex_unlock(&ec_data->mec_mutex); - if ((inb_p(MCHP_EMI0_EC_DATA_BYTE0) != 'M') && - (inb_p(MCHP_EMI0_EC_DATA_BYTE1) != 'C') && - (inb_p(MCHP_EMI0_EC_DATA_BYTE2) != 'H') && + if ((inb_p(MCHP_EMI0_EC_DATA_BYTE0) != 'M') || + (inb_p(MCHP_EMI0_EC_DATA_BYTE1) != 'C') || + (inb_p(MCHP_EMI0_EC_DATA_BYTE2) != 'H') || (inb_p(MCHP_EMI0_EC_DATA_BYTE3) != 'P')) return -ENODEV; |