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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-05-03 13:17:12 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-16 10:06:52 +0200
commit46864b108b00bda066f5774785efbe82a4439a84 (patch)
tree44f45a05686bcb3763552a46286eb4d5c7f3c693 /drivers/atm
parent0df23e9b9b2f0293b873145bd22d218d2940dfaa (diff)
atm: zatm: Fix potential Spectre v1
commit 2be147f7459db5bbf292e0a6f135037b55e20b39 upstream. pool 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/atm/zatm.c:1462 zatm_ioctl() warn: potential spectre issue 'zatm_dev->pool_info' (local cap) Fix this by sanitizing pool before using it to index zatm_dev->pool_info 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> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/atm')
-rw-r--r--drivers/atm/zatm.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/atm/zatm.c b/drivers/atm/zatm.c
index cecfb943762f..6eab52b92e01 100644
--- a/drivers/atm/zatm.c
+++ b/drivers/atm/zatm.c
@@ -23,6 +23,7 @@
#include <linux/bitops.h>
#include <linux/wait.h>
#include <linux/slab.h>
+#include <linux/nospec.h>
#include <asm/byteorder.h>
#include <asm/string.h>
#include <asm/io.h>
@@ -1456,6 +1457,8 @@ static int zatm_ioctl(struct atm_dev *dev,unsigned int cmd,void __user *arg)
return -EFAULT;
if (pool < 0 || pool > ZATM_LAST_POOL)
return -EINVAL;
+ pool = array_index_nospec(pool,
+ ZATM_LAST_POOL + 1);
spin_lock_irqsave(&zatm_dev->lock, flags);
info = zatm_dev->pool_info[pool];
if (cmd == ZATM_GETPOOLZ) {