hwmon: (pc87360) Bounds check data->innr usage
authorKees Cook <keescook@chromium.org>
Thu, 30 Nov 2023 20:02:07 +0000 (12:02 -0800)
committerGuenter Roeck <linux@roeck-us.net>
Mon, 11 Dec 2023 14:21:01 +0000 (06:21 -0800)
commit4265eb062a7303e537ab3792ade31f424c3c5189
treeab37b3d3e2d41411026c8f7f84df1cfe5e3e5792
parent8b3800256abad20e91c2698607f9b28591407b19
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 <jim.cromie@gmail.com>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-hwmon@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20231130200207.work.679-kees@kernel.org
[groeck: Added comment into code clarifying context]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
drivers/hwmon/pc87360.c