From: David Long <dave.long@linaro.org>
To: stable@vger.kernel.org,
Russell King - ARM Linux <linux@armlinux.org.uk>,
Florian Fainelli <f.fainelli@gmail.com>,
Julien Thierry <julien.thierry@arm.com>,
Tony Lindgren <tony@atomide.com>,
Marc Zyngier <marc.zyngier@arm.com>,
Mark Rutland <mark.rutland@arm.com>
Cc: Greg KH <gregkh@linuxfoundation.org>, Mark Brown <broonie@kernel.org>
Subject: [PATCH 4.14 06/17] ARM: 8794/1: uaccess: Prevent speculative use of the current addr_limit
Date: Thu, 10 Jan 2019 12:51:39 -0500 [thread overview]
Message-ID: <20190110175150.5239-7-dave.long@linaro.org> (raw)
In-Reply-To: <20190110175150.5239-1-dave.long@linaro.org>
From: Julien Thierry <julien.thierry@arm.com>
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>
---
arch/arm/include/asm/uaccess.h | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 4140be431087..7d19584f5c39 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -69,6 +69,14 @@ extern int __put_user_bad(void);
static inline void set_fs(mm_segment_t fs)
{
current_thread_info()->addr_limit = fs;
+
+ /*
+ * Prevent a mispredicted conditional call to set_fs from forwarding
+ * the wrong address limit to access_ok under speculation.
+ */
+ dsb(nsh);
+ isb();
+
modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
}
--
2.17.1
next prev parent reply other threads:[~2019-01-10 17:52 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-10 17:51 [PATCH 4.14 00/17] V4.14 backport of more 32-bit arm spectre patches David Long
2019-01-10 17:51 ` [PATCH 4.14 01/17] ARM: 8789/1: signal: copy registers using __copy_to_user() David Long
2019-01-10 17:51 ` [PATCH 4.14 02/17] ARM: 8790/1: signal: always use __copy_to_user to save iwmmxt context David Long
2019-01-10 17:51 ` [PATCH 4.14 03/17] ARM: 8791/1: vfp: use __copy_to_user() when saving VFP state David Long
2019-01-10 17:51 ` [PATCH 4.14 04/17] ARM: 8792/1: oabi-compat: copy oabi events using __copy_to_user() David Long
2019-01-10 17:51 ` [PATCH 4.14 05/17] ARM: 8793/1: signal: replace __put_user_error with __put_user David Long
2019-01-10 17:51 ` David Long [this message]
2019-01-10 17:51 ` [PATCH 4.14 07/17] ARM: 8795/1: spectre-v1.1: use put_user() for __put_user() David Long
2019-01-10 17:51 ` [PATCH 4.14 08/17] ARM: 8796/1: spectre-v1,v1.1: provide helpers for address sanitization David Long
2019-01-10 17:51 ` [PATCH 4.14 09/17] ARM: 8797/1: spectre-v1.1: harden __copy_to_user David Long
2019-01-10 17:51 ` [PATCH 4.14 10/17] ARM: 8810/1: vfp: Fix wrong assignement to ufp_exc David Long
2019-01-10 17:51 ` [PATCH 4.14 11/17] ARM: make lookup_processor_type() non-__init David Long
2019-01-10 17:51 ` [PATCH 4.14 12/17] ARM: split out processor lookup David Long
2019-01-10 17:51 ` [PATCH 4.14 13/17] ARM: clean up per-processor check_bugs method call David Long
2019-01-10 17:51 ` [PATCH 4.14 14/17] ARM: add PROC_VTABLE and PROC_TABLE macros David Long
2019-01-10 17:51 ` [PATCH 4.14 15/17] ARM: spectre-v2: per-CPU vtables to work around big.Little systems David Long
2019-01-10 17:51 ` [PATCH 4.14 16/17] ARM: ensure that processor vtables is not lost after boot David Long
2019-01-10 17:51 ` [PATCH 4.14 17/17] ARM: fix the cockup in the previous patch David Long
2019-01-15 15:45 ` [PATCH 4.14 00/17] V4.14 backport of more 32-bit arm spectre patches Greg KH
2019-01-15 16:07 ` David Long
2019-01-15 16:30 ` Greg KH
2019-01-15 16:39 ` David Long
2019-01-15 17:06 ` Russell King - ARM Linux admin
2019-01-15 17:19 ` Greg KH
2019-01-16 19:27 ` David Long
2019-01-16 19:33 ` Greg KH
2019-01-16 19:40 ` David Long
2019-01-16 19:48 ` Greg KH
2019-01-16 19:49 ` Russell King - ARM Linux admin
2019-01-18 16:07 ` Greg KH
2019-01-18 20:24 ` David Long
2019-01-19 8:08 ` Greg KH
2019-01-19 9:56 ` Russell King - ARM Linux admin
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