Commit 537094b6 authored May 07, 2014 by Andrey Ryabinin Committed by Russell King May 25, 2014

ARM: 8051/1: put_user: fix possible data corruption in put_user



According to arm procedure call standart r2 register is call-cloberred.
So after the result of x expression was put into r2 any following
function call in p may overwrite r2. To fix this, the result of p
expression must be saved to the temporary variable before the
assigment x expression to __r2.

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent f9ff907b

arch/arm/include/asm/uaccess.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -171,8 +171,9 @@ extern int __put_user_8(void *, unsigned long long);
		#define __put_user_check(x,p) \
		({ \
		unsigned long __limit = current_thread_info()->addr_limit - 1; \
		const typeof((p)) __user __tmp_p = (p); \
		register const typeof(*(p)) __r2 asm("r2") = (x); \
		register const typeof((p)) __user __p asm("r0") = (p);\
		register const typeof((p)) __user __p asm("r0") = __tmp_p; \
		register unsigned long __l asm("r1") = __limit; \
		register int __e asm("r0"); \
		switch (sizeof(*(__p))) { \