hwmon: (nct6775) Fix potential Spectre v1
commit
d49dbfade96d5b0863ca8a90122a805edd5ef50a upstream.
val can be indirectly controlled by user-space, hence leading to
a potential exploitation of the Spectre variant 1 vulnerability.
This issue was detected with the help of Smatch:
vers/hwmon/nct6775.c:2698 store_pwm_weight_temp_sel() warn: potential
spectre issue 'data->temp_src' [r]
Fix this by sanitizing val before using it to index data->temp_src
Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].
[1] https://marc.info/?l=linux-kernel&m=
152449131114778&w=2
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>