diff options
| author | Andrey Ryabinin <a.ryabinin@samsung.com> | 2014-05-07 08:07:25 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2014-05-25 23:44:25 +0100 |
| commit | 537094b64b229bf3ad146042f83e74cf6abe59df (patch) | |
| tree | 746795d32d38c8c0affefa22c6c1154d2ddd4e32 | |
| parent | f9ff907b0af561dcde4683f7c9f71dc0f41d3be3 (diff) | |
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>
| -rw-r--r-- | arch/arm/include/asm/uaccess.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 12c3a5decc60..75d95799b6e6 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))) { \ |