Julien Thierry f8c5a575c5 ARM: 8794/1: uaccess: Prevent speculative use of the current addr_limit
Commit 621afc677465db231662ed126ae1f355bf8eac47 upstream.

A mispredicted conditional call to set_fs could result in the wrong
addr_limit being forwarded under speculation to a subsequent access_ok
check, potentially forming part of a spectre-v1 attack using uaccess
routines.

This patch prevents this forwarding from taking place, but putting heavy
barriers in set_fs after writing the addr_limit.

Porting commit c2f0ad4fc089cff8 ("arm64: uaccess: Prevent speculative use
of the current addr_limit").

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David A. Long <dave.long@linaro.org>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-10 11:21:34 +01:00
..
2019-02-20 10:13:22 +01:00
2019-09-21 07:12:54 +02:00
2016-09-24 10:07:43 +02:00