diff options
authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-08-15 08:14:37 -0500
committerGuenter Roeck <linux@roeck-us.net>2018-08-26 17:45:25 -0700
commitd49dbfade96d5b0863ca8a90122a805edd5ef50a (patch)
parentf196dec6d50abb2e65fb54a0621b2f1b4d922995 (diff)
hwmon: (nct6775) Fix potential Spectre v1
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>
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/hwmon/nct6775.c b/drivers/hwmon/nct6775.c
index c6bd61e4695a..944f5b63aecd 100644
--- a/drivers/hwmon/nct6775.c
+++ b/drivers/hwmon/nct6775.c
@@ -63,6 +63,7 @@
#include <linux/bitops.h>
#include <linux/dmi.h>
#include <linux/io.h>
+#include <linux/nospec.h>
#include "lm75.h"
@@ -2689,6 +2690,7 @@ store_pwm_weight_temp_sel(struct device *dev, struct device_attribute *attr,
return err;
if (val > NUM_TEMP)
return -EINVAL;
+ val = array_index_nospec(val, NUM_TEMP + 1);
if (val && (!(data->have_temp & BIT(val - 1)) ||
!data->temp_src[val - 1]))
return -EINVAL;