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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-10-16 15:06:41 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-12-16 22:09:42 +0000 |
| commit | e9dbac343870ad5d33c60c42de1b31c3da6dfebe (patch) | |
| tree | 0faa824ed6818ef82b279b303e3646403e55058e /drivers/ptp/ptp_chardev.c | |
| parent | 2e253a0ca95a8ccfd172f60bf08f259181abd646 (diff) | |
| download | linux-stable-e9dbac343870ad5d33c60c42de1b31c3da6dfebe.tar.gz linux-stable-e9dbac343870ad5d33c60c42de1b31c3da6dfebe.tar.bz2 linux-stable-e9dbac343870ad5d33c60c42de1b31c3da6dfebe.zip | |
ptp: fix Spectre v1 vulnerability
commit efa61c8cf2950ab5c0e66cff3cabe2a2b24e81ba upstream.
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
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers/ptp/ptp_chardev.c')
| -rw-r--r-- | drivers/ptp/ptp_chardev.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c index 419056d7887e..f5cf901b2f2b 100644 --- a/drivers/ptp/ptp_chardev.c +++ b/drivers/ptp/ptp_chardev.c @@ -23,6 +23,8 @@ #include <linux/sched.h> #include <linux/slab.h> +#include <linux/nospec.h> + #include "ptp_private.h" static int ptp_disable_pinfunc(struct ptp_clock_info *ops, @@ -228,6 +230,7 @@ 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]; @@ -246,6 +249,7 @@ 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); |