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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-05-03 13:17:12 -0500
committerDavid S. Miller <davem@davemloft.net>2018-05-04 12:52:47 -0400
commit2be147f7459db5bbf292e0a6f135037b55e20b39 (patch)
tree24d26b101cb213841eb1b907e42f8c899b639ab2 /drivers/atm
parent72f17baf2352ded6a1d3f4bb2d15da8c678cd2cb (diff)
downloadlinux-2be147f7459db5bbf292e0a6f135037b55e20b39.tar.bz2
atm: zatm: Fix potential Spectre v1
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>
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 1ef67db03c8e..9c9a22958717 100644
--- a/drivers/atm/zatm.c
+++ b/drivers/atm/zatm.c
@@ -28,6 +28,7 @@
#include <asm/io.h>
#include <linux/atomic.h>
#include <linux/uaccess.h>
+#include <linux/nospec.h>
#include "uPD98401.h"
#include "uPD98402.h"
@@ -1458,6 +1459,8 @@ 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) {