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arm64: uaccess: implement unsafe accessors 

Current implementation of get/put_user_unsafe default to get/put_user
which toggle PAN before each access, despite having been told by the caller
that multiple accesses to user memory were about to happen.

Provide implementations for user_access_begin/end to turn PAN off/on and
implement unsafe accessors that assume PAN was already turned off.

Tested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Julien Thierry 2018-09-06 12:09:56 +01:00 committed by Catalin Marinas
parent 4733c7c79e
commit a1f33941f7
1 changed files with 46 additions and 15 deletions
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61
arch/arm64/include/asm/uaccess.h
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@ -277,11 +277,9 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
: "+r" (err), "=&r" (x) \
: "r" (addr), "i" (-EFAULT))
#define __get_user_err(x, ptr, err) \
#define __get_user_err_unsafe(x, ptr, err) \
do { \
unsigned long __gu_val; \
__chk_user_ptr(ptr); \
uaccess_enable_not_uao(); \
switch (sizeof(*(ptr))) { \
case 1: \
__get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \
@ -302,17 +300,24 @@ do { \
default: \
BUILD_BUG(); \
} \
uaccess_disable_not_uao(); \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
} while (0)
#define __get_user_check(x, ptr, err) \
#define __get_user_err_check(x, ptr, err) \
do { \
__chk_user_ptr(ptr); \
uaccess_enable_not_uao(); \
__get_user_err_unsafe((x), (ptr), (err)); \
uaccess_disable_not_uao(); \
} while (0)
#define __get_user_err(x, ptr, err, accessor) \
({ \
__typeof__(*(ptr)) __user *__p = (ptr); \
might_fault(); \
if (access_ok(VERIFY_READ, __p, sizeof(*__p))) { \
__p = uaccess_mask_ptr(__p); \
__get_user_err((x), __p, (err)); \
accessor((x), __p, (err)); \
} else { \
(x) = 0; (err) = -EFAULT; \
} \
@ -320,14 +325,14 @@ do { \
#define __get_user_error(x, ptr, err) \
({ \
__get_user_check((x), (ptr), (err)); \
__get_user_err((x), (ptr), (err), __get_user_err_check); \
(void)0; \
})
#define __get_user(x, ptr) \
({ \
int __gu_err = 0; \
__get_user_check((x), (ptr), __gu_err); \
__get_user_err((x), (ptr), __gu_err, __get_user_err_check); \
__gu_err; \
})
@ -347,11 +352,9 @@ do { \
: "+r" (err) \
: "r" (x), "r" (addr), "i" (-EFAULT))
#define __put_user_err(x, ptr, err) \
#define __put_user_err_unsafe(x, ptr, err) \
do { \
__typeof__(*(ptr)) __pu_val = (x); \
__chk_user_ptr(ptr); \
uaccess_enable_not_uao(); \
switch (sizeof(*(ptr))) { \
case 1: \
__put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \
@ -372,16 +375,24 @@ do { \
default: \
BUILD_BUG(); \
} \
} while (0)
#define __put_user_err_check(x, ptr, err) \
do { \
__chk_user_ptr(ptr); \
uaccess_enable_not_uao(); \
__put_user_err_unsafe((x), (ptr), (err)); \
uaccess_disable_not_uao(); \
} while (0)
#define __put_user_check(x, ptr, err) \
#define __put_user_err(x, ptr, err, accessor) \
({ \
__typeof__(*(ptr)) __user *__p = (ptr); \
might_fault(); \
if (access_ok(VERIFY_WRITE, __p, sizeof(*__p))) { \
__p = uaccess_mask_ptr(__p); \
__put_user_err((x), __p, (err)); \
accessor((x), __p, (err)); \
} else { \
(err) = -EFAULT; \
} \
@ -389,19 +400,39 @@ do { \
#define __put_user_error(x, ptr, err) \
({ \
__put_user_check((x), (ptr), (err)); \
__put_user_err((x), (ptr), (err), __put_user_err_check); \
(void)0; \
})
#define __put_user(x, ptr) \
({ \
int __pu_err = 0; \
__put_user_check((x), (ptr), __pu_err); \
__put_user_err((x), (ptr), __pu_err, __put_user_err_check); \
__pu_err; \
})
#define put_user __put_user
#define user_access_begin() uaccess_enable_not_uao()
#define user_access_end() uaccess_disable_not_uao()
#define unsafe_get_user(x, ptr, err) \
do { \
int __gu_err = 0; \
__get_user_err((x), (ptr), __gu_err, __get_user_err_unsafe); \
if (__gu_err != 0) \
goto err; \
} while (0)
#define unsafe_put_user(x, ptr, err) \
do { \
int __pu_err = 0; \
__put_user_err((x), (ptr), __pu_err, __put_user_err_unsafe); \
if (__pu_err != 0) \
goto err; \
} while (0)
extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
#define raw_copy_from_user(to, from, n) \
({ \