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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2019-07-30 22:21:41 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-11 12:22:16 +0200 |
| commit | b5641e517bd2a44842472424897352b4ae667075 (patch) | |
| tree | 419fbe1657e6b2e3b12ff5ef2b628713e7b28a46 | |
| parent | 22395a3e46d611644fdd7b25c521a040dc2e8b51 (diff) | |
| download | linux-rt-b5641e517bd2a44842472424897352b4ae667075.tar.gz | |
atm: iphase: Fix Spectre v1 vulnerability
[ Upstream commit ea443e5e98b5b74e317ef3d26bcaea54931ccdee ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/atm/iphase.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/atm/iphase.c b/drivers/atm/iphase.c index b2756765950e..fe47c924dc64 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: |