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authorGustavo A. R. Silva <gustavo@embeddedor.com>2019-07-30 22:21:41 -0500
committerDavid S. Miller <davem@davemloft.net>2019-08-02 17:30:36 -0700
commitea443e5e98b5b74e317ef3d26bcaea54931ccdee (patch)
treebec48b840e6e8aca80e399e9cde1db571b7ba9b1 /drivers/atm
parent685703b497bacea8765bb409d6b73455b73c540e (diff)
downloadlinux-ea443e5e98b5b74e317ef3d26bcaea54931ccdee.tar.bz2
atm: iphase: Fix Spectre v1 vulnerability
board is 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/atm/iphase.c:2765 ia_ioctl() warn: potential spectre issue 'ia_dev' [r] (local cap) drivers/atm/iphase.c:2774 ia_ioctl() warn: possible spectre second half. 'iadev' drivers/atm/iphase.c:2782 ia_ioctl() warn: possible spectre second half. 'iadev' drivers/atm/iphase.c:2816 ia_ioctl() warn: possible spectre second half. 'iadev' drivers/atm/iphase.c:2823 ia_ioctl() warn: possible spectre second half. 'iadev' drivers/atm/iphase.c:2830 ia_ioctl() warn: potential spectre issue '_ia_dev' [r] (local cap) drivers/atm/iphase.c:2845 ia_ioctl() warn: possible spectre second half. 'iadev' drivers/atm/iphase.c:2856 ia_ioctl() warn: possible spectre second half. 'iadev' Fix this by sanitizing board before using it to index ia_dev and _ia_dev 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://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/ Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/atm')
-rw-r--r--drivers/atm/iphase.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/atm/iphase.c b/drivers/atm/iphase.c
index 302cf0ba1600..8c7a996d1f16 100644
--- a/drivers/atm/iphase.c
+++ b/drivers/atm/iphase.c
@@ -63,6 +63,7 @@
#include <asm/byteorder.h>
#include <linux/vmalloc.h>
#include <linux/jiffies.h>
+#include <linux/nospec.h>
#include "iphase.h"
#include "suni.h"
#define swap_byte_order(x) (((x & 0xff) << 8) | ((x & 0xff00) >> 8))
@@ -2760,8 +2761,11 @@ static int ia_ioctl(struct atm_dev *dev, unsigned int cmd, void __user *arg)
}
if (copy_from_user(&ia_cmds, arg, sizeof ia_cmds)) return -EFAULT;
board = ia_cmds.status;
- if ((board < 0) || (board > iadev_count))
- board = 0;
+
+ if ((board < 0) || (board > iadev_count))
+ board = 0;
+ board = array_index_nospec(board, iadev_count + 1);
+
iadev = ia_dev[board];
switch (ia_cmds.cmd) {
case MEMDUMP: