commit 2be147f7459db5bbf292e0a6f135037b55e20b39
author Gustavo A. R. Silva <gustavo@embeddedor.com> Thu May 03 13:17:12 2018 -0500
committer David S. Miller <davem@davemloft.net> Fri May 04 12:52:47 2018 -0400
tree 24d26b101cb213841eb1b907e42f8c899b639ab2
parent 72f17baf2352ded6a1d3f4bb2d15da8c678cd2cb

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>