linux-kernel - [PATCH 4.19 09/17] ARM: 8797/1: spectre-v1.1: harden __copy_to

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Date:   Wed, 13 Feb 2019 16:32:15 -0500
From:   David Long <dave.long@...aro.org>
To:     stable@...r.kernel.org,
        Russell King - ARM Linux <linux@...linux.org.uk>,
        Florian Fainelli <f.fainelli@...il.com>,
        Julien Thierry <julien.thierry@....com>,
        Tony Lindgren <tony@...mide.com>,
        Marc Zyngier <marc.zyngier@....com>,
        Greg KH <gregkh@...uxfoundation.org>,
        Mark Rutland <mark.rutland@....com>
Cc:     Will Deacon <will.deacon@....com>, Mark Brown <broonie@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 4.19 09/17] ARM: 8797/1: spectre-v1.1: harden __copy_to_user

From: Julien Thierry <julien.thierry@....com>

Commit a1d09e074250fad24f1b993f327b18cc6812eb7a upstream.

Sanitize user pointer given to __copy_to_user, both for standard version
and memcopy version of the user accessor.

Signed-off-by: Julien Thierry <julien.thierry@....com>
Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
Signed-off-by: David A. Long <dave.long@...aro.org>
---
 arch/arm/lib/copy_to_user.S        | 6 +++++-
 arch/arm/lib/uaccess_with_memcpy.c | 3 ++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/arm/lib/copy_to_user.S b/arch/arm/lib/copy_to_user.S
index caf5019d8161..970abe521197 100644
--- a/arch/arm/lib/copy_to_user.S
+++ b/arch/arm/lib/copy_to_user.S
@@ -94,6 +94,11 @@
 
 ENTRY(__copy_to_user_std)
 WEAK(arm_copy_to_user)
+#ifdef CONFIG_CPU_SPECTRE
+	get_thread_info r3
+	ldr	r3, [r3, #TI_ADDR_LIMIT]
+	uaccess_mask_range_ptr r0, r2, r3, ip
+#endif
 
 #include "copy_template.S"
 
@@ -108,4 +113,3 @@ ENDPROC(__copy_to_user_std)
 	rsb	r0, r0, r2
 	copy_abort_end
 	.popsection
-
diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c
index 9b4ed1728616..73dc7360cbdd 100644
--- a/arch/arm/lib/uaccess_with_memcpy.c
+++ b/arch/arm/lib/uaccess_with_memcpy.c
@@ -152,7 +152,8 @@ arm_copy_to_user(void __user *to, const void *from, unsigned long n)
 		n = __copy_to_user_std(to, from, n);
 		uaccess_restore(ua_flags);
 	} else {
-		n = __copy_to_user_memcpy(to, from, n);
+		n = __copy_to_user_memcpy(uaccess_mask_range_ptr(to, n),
+					  from, n);
 	}
 	return n;
 }
-- 
2.17.1