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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-10-16 16:06:41 +0300
committerDavid S. Miller <davem@davemloft.net>2018-10-18 08:00:22 +0300
commitefa61c8cf2950ab5c0e66cff3cabe2a2b24e81ba (patch)
treeaca302d3439f23b8282062a9c738485372d7ea9f /drivers/ptp/ptp_chardev.c
parent8c3bf9b62b667456a57aefcf1689e826df146159 (diff)
downloadlinux-efa61c8cf2950ab5c0e66cff3cabe2a2b24e81ba.tar.xz
ptp: fix Spectre v1 vulnerability
pin_index 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: drivers/ptp/ptp_chardev.c:253 ptp_ioctl() warn: potential spectre issue 'ops->pin_config' [r] (local cap) Fix this by sanitizing pin_index before using it to index ops->pin_config, and before passing it as an argument to function ptp_set_pinfunc(), in which it is used to index info->pin_config. 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> Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/ptp/ptp_chardev.c')
-rw-r--r--drivers/ptp/ptp_chardev.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 01b0e2bb3319..2012551d93e0 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -24,6 +24,8 @@
#include <linux/slab.h>
#include <linux/timekeeping.h>
+#include <linux/nospec.h>
+
#include "ptp_private.h"
static int ptp_disable_pinfunc(struct ptp_clock_info *ops,
@@ -248,6 +250,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
err = -EINVAL;
break;
}
+ pin_index = array_index_nospec(pin_index, ops->n_pins);
if (mutex_lock_interruptible(&ptp->pincfg_mux))
return -ERESTARTSYS;
pd = ops->pin_config[pin_index];
@@ -266,6 +269,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
err = -EINVAL;
break;
}
+ pin_index = array_index_nospec(pin_index, ops->n_pins);
if (mutex_lock_interruptible(&ptp->pincfg_mux))
return -ERESTARTSYS;
err = ptp_set_pinfunc(ptp, pin_index, pd.func, pd.chan);