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| author | Andrey Ryabinin <a.ryabinin@samsung.com> | 2014-05-07 08:07:25 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-06-11 12:03:23 -0700 |
| commit | b1da22af26d907e88925c2ce1a9ee527bd899875 (patch) | |
| tree | 3c5aebe24fa1a754f866a3edd191f3825df2b386 | |
| parent | c506847413e50969d24e26bc00595e982796a5dc (diff) | |
| download | lwn-b1da22af26d907e88925c2ce1a9ee527bd899875.tar.gz lwn-b1da22af26d907e88925c2ce1a9ee527bd899875.zip | |
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>
| -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 7e1f76027f66..20e1c994669e 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -164,8 +164,9 @@ 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))) { \ |