path: root/arch
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authorAndrey Ryabinin <a.ryabinin@samsung.com>2014-05-07 08:07:25 +0100
committerShow Liu <show.liu@linaro.org>2014-06-18 12:05:21 +0800
commit2cbbfce93bbb6190113d65bb1848b103e7d805cc (patch)
tree8f017c8d54d78502c3922790c16a1cd26af4ad0e /arch
parentb8ed6e870ad2ace9719d567d122e0724b0e3910c (diff)
ARM: 8051/1: put_user: fix possible data corruption in put_user
commit 537094b64b229bf3ad146042f83e74cf6abe59df upstream. 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> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 72abdc541f3..7f3f3cc25d7 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -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))) { \