Re: [PATCH] atm: zatm: Fix potential Spectre v1

[David Miller]

From: "Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx>
Date: Thu, 3 May 2018 13:17:12 -0500

> 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@xxxxxxxxxxxxxxx
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>

Applied and queued up for -stable.