From 4265eb062a7303e537ab3792ade31f424c3c5189 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 30 Nov 2023 12:02:07 -0800 Subject: hwmon: (pc87360) Bounds check data->innr usage Without visibility into the initializers for data->innr, GCC suspects using it as an index could walk off the end of the various 14-element arrays in data. Perform an explicit clamp to the array size. Silences the following warning with GCC 12+: ../drivers/hwmon/pc87360.c: In function 'pc87360_update_device': ../drivers/hwmon/pc87360.c:341:49: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=] 341 | data->in_max[i] = pc87360_read_value(data, | ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~ 342 | LD_IN, i, | ~~~~~~~~~ 343 | PC87365_REG_IN_MAX); | ~~~~~~~~~~~~~~~~~~~ ../drivers/hwmon/pc87360.c:209:12: note: at offset 255 into destination object 'in_max' of size 14 209 | u8 in_max[14]; /* Register value */ | ^~~~~~ Cc: Jim Cromie Cc: Jean Delvare Cc: Guenter Roeck Cc: linux-hwmon@vger.kernel.org Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/20231130200207.work.679-kees@kernel.org [groeck: Added comment into code clarifying context] Signed-off-by: Guenter Roeck --- drivers/hwmon/pc87360.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/hwmon') diff --git a/drivers/hwmon/pc87360.c b/drivers/hwmon/pc87360.c index 926ea1fe133c..9e9681b2e8c5 100644 --- a/drivers/hwmon/pc87360.c +++ b/drivers/hwmon/pc87360.c @@ -323,7 +323,11 @@ static struct pc87360_data *pc87360_update_device(struct device *dev) } /* Voltages */ - for (i = 0; i < data->innr; i++) { + /* + * The min() below does not have any practical meaning and is + * only needed to silence a warning observed with gcc 12+. + */ + for (i = 0; i < min(data->innr, ARRAY_SIZE(data->in)); i++) { data->in_status[i] = pc87360_read_value(data, LD_IN, i, PC87365_REG_IN_STATUS); /* Clear bits */ -- cgit v1.2.3