From fc320be61ff66604309d96cf1dee4ad3bb040d3d Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 15 Aug 2018 10:50:41 -0500 Subject: [PATCH] misc: hmc6352: fix potential Spectre v1 commit de916736aaaadddbd6061472969f667b14204aa9 upstream. val is 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: drivers/misc/hmc6352.c:54 compass_store() warn: potential spectre issue 'map' [r] Fix this by sanitizing val before using it to index map 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 Signed-off-by: Greg Kroah-Hartman --- drivers/misc/hmc6352.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/misc/hmc6352.c b/drivers/misc/hmc6352.c index eeb7eef62174..38f90e179927 100644 --- a/drivers/misc/hmc6352.c +++ b/drivers/misc/hmc6352.c @@ -27,6 +27,7 @@ #include #include #include +#include static DEFINE_MUTEX(compass_mutex); @@ -50,6 +51,7 @@ static int compass_store(struct device *dev, const char *buf, size_t count, return ret; if (val >= strlen(map)) return -EINVAL; + val = array_index_nospec(val, strlen(map)); mutex_lock(&compass_mutex); ret = compass_command(c, map[val]); mutex_unlock(&compass_mutex); -- 2.50.1