This is a note to let you know that I've just added the patch titled
ptp: fix Spectre v1 vulnerability
to the 4.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ptp-fix-spectre-v1-vulnerability.patch
and it can be found in the queue-4.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From efa61c8cf2950ab5c0e66cff3cabe2a2b24e81ba Mon Sep 17 00:00:00 2001
From: "Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx>
Date: Tue, 16 Oct 2018 15:06:41 +0200
Subject: ptp: fix Spectre v1 vulnerability
From: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
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
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Acked-by: Richard Cochran <richardcochran@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/ptp/ptp_chardev.c | 4 ++++
1 file changed, 4 insertions(+)
--- 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, u
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, u
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);
Patches currently in stable-queue which might be from gustavo@xxxxxxxxxxxxxx are
queue-4.18/ptp-fix-spectre-v1-vulnerability.patch
queue-4.18/rdma-ucma-fix-spectre-v1-vulnerability.patch
queue-4.18/usb-gadget-storage-fix-spectre-v1-vulnerability.patch
queue-4.18/ib-ucm-fix-spectre-v1-vulnerability.patch
