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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-06-29 13:28:07 -0500
committerDavid S. Miller <davem@davemloft.net>2018-06-30 21:24:18 +0900
commitced9e191501e52b95e1b57b8e0db00943869eed0 (patch)
tree4dd2099f5eabd75c7d66a217762edcffe8991df6 /drivers/atm
parentc7f653e0a8cf4e4a9951324f9b831cf88d813e48 (diff)
downloadlinux-ced9e191501e52b95e1b57b8e0db00943869eed0.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:1491 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 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.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/atm/zatm.c b/drivers/atm/zatm.c
index a8d2eb0ceb8d..2c288d1f42bb 100644
--- a/drivers/atm/zatm.c
+++ b/drivers/atm/zatm.c
@@ -1483,6 +1483,8 @@ 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);
if (copy_from_user(&info,
&((struct zatm_pool_req __user *) arg)->info,
sizeof(info))) return -EFAULT;