misc: hmc6352: fix potential Spectre v1
commit de916736aa
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 <gustavo@embeddedor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
parent
47358b34ba
commit
fc320be61f
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@ -27,6 +27,7 @@
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/sysfs.h>
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#include <linux/nospec.h>
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static DEFINE_MUTEX(compass_mutex);
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@ -50,6 +51,7 @@ static int compass_store(struct device *dev, const char *buf, size_t count,
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return ret;
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if (val >= strlen(map))
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return -EINVAL;
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val = array_index_nospec(val, strlen(map));
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mutex_lock(&compass_mutex);
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ret = compass_command(c, map[val]);
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mutex_unlock(&compass_mutex);
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