linux-kernel - [PATCH 3.16 14/19] MIPS: Zero variable read by get_user / __get

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Date:   Sat, 01 Apr 2017 14:17:50 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Arnd Bergmann" <arnd@...db.de>,
        "Ralf Baechle" <ralf@...ux-mips.org>
Subject: [PATCH 3.16 14/19] MIPS: Zero variable read by get_user /
 __get_user in case of an error.

3.16.43-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Ralf Baechle <ralf@...ux-mips.org>

commit 640465bda58c7078725201be7430c31a349121e9 upstream.

This wasn't happening in all cases.

Signed-off-by: Ralf Baechle <ralf@...ux-mips.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
Cc: Arnd Bergmann <arnd@...db.de>
---
 arch/mips/include/asm/uaccess.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/arch/mips/include/asm/uaccess.h
+++ b/arch/mips/include/asm/uaccess.h
@@ -302,7 +302,8 @@ do {									\
 			__get_kernel_common((x), size, __gu_ptr);	\
 		else							\
 			__get_user_common((x), size, __gu_ptr);		\
-	}								\
+	} else								\
+		(x) = 0;						\
 									\
 	__gu_err;							\
 })
@@ -317,6 +318,7 @@ do {									\
 	"	.insn						\n"	\
 	"	.section .fixup,\"ax\"				\n"	\
 	"3:	li	%0, %4					\n"	\
+	"	move	%1, $0					\n"	\
 	"	j	2b					\n"	\
 	"	.previous					\n"	\
 	"	.section __ex_table,\"a\"			\n"	\
@@ -631,6 +633,7 @@ do {									\
 	"	.insn						\n"	\
 	"	.section .fixup,\"ax\"				\n"	\
 	"3:	li	%0, %4					\n"	\
+	"	move	%1, $0					\n"	\
 	"	j	2b					\n"	\
 	"	.previous					\n"	\
 	"	.section __ex_table,\"a\"			\n"	\