Messages in this thread Patch in this message | | | Date | Fri, 29 Jun 2018 13:28:07 -0500 | From | "Gustavo A. R. Silva" <> | Subject | [PATCH] atm: zatm: Fix potential Spectre v1 |
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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
Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- drivers/atm/zatm.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/atm/zatm.c b/drivers/atm/zatm.c index a8d2eb0..2c288d1 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; -- 2.7.4
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