This is a note to let you know that I've just added the patch titled ARM: 8051/1: put_user: fix possible data corruption in put_user to the 3.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm-8051-1-put_user-fix-possible-data-corruption-in-put_user.patch and it can be found in the queue-3.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 537094b64b229bf3ad146042f83e74cf6abe59df Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx> Date: Wed, 7 May 2014 08:07:25 +0100 Subject: ARM: 8051/1: put_user: fix possible data corruption in put_user From: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx> 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@xxxxxxxxxxx> Reviewed-by: Nicolas Pitre <nico@xxxxxxxxxx> Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm/include/asm/uaccess.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -158,8 +158,9 @@ extern int __put_user_8(void *, unsigned #define put_user(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))) { \ Patches currently in stable-queue which might be from a.ryabinin@xxxxxxxxxxx are queue-3.4/arm-8051-1-put_user-fix-possible-data-corruption-in-put_user.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html