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.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Julien Thierry 2019-01-15 13:58:27 +00:00 committed by Catalin Marinas
parent 13e4cdd785
commit 0bd3ef34d2
1 changed files with 59 additions and 20 deletions

View File

@ -270,31 +270,26 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
#define __raw_get_user(x, ptr, err) \ #define __raw_get_user(x, ptr, err) \
do { \ do { \
unsigned long __gu_val; \
__chk_user_ptr(ptr); \
uaccess_enable_not_uao(); \
switch (sizeof(*(ptr))) { \ switch (sizeof(*(ptr))) { \
case 1: \ case 1: \
__get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \ __get_user_asm("ldrb", "ldtrb", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \ (err), ARM64_HAS_UAO); \
break; \ break; \
case 2: \ case 2: \
__get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr), \ __get_user_asm("ldrh", "ldtrh", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \ (err), ARM64_HAS_UAO); \
break; \ break; \
case 4: \ case 4: \
__get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr), \ __get_user_asm("ldr", "ldtr", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \ (err), ARM64_HAS_UAO); \
break; \ break; \
case 8: \ case 8: \
__get_user_asm("ldr", "ldtr", "%x", __gu_val, (ptr), \ __get_user_asm("ldr", "ldtr", "%x", (x), (ptr), \
(err), ARM64_HAS_UAO); \ (err), ARM64_HAS_UAO); \
break; \ break; \
default: \ default: \
BUILD_BUG(); \ BUILD_BUG(); \
} \ } \
uaccess_disable_not_uao(); \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
} while (0) } while (0)
#define __get_user_error(x, ptr, err) \ #define __get_user_error(x, ptr, err) \
@ -302,8 +297,13 @@ do { \
__typeof__(*(ptr)) __user *__p = (ptr); \ __typeof__(*(ptr)) __user *__p = (ptr); \
might_fault(); \ might_fault(); \
if (access_ok(__p, sizeof(*__p))) { \ if (access_ok(__p, sizeof(*__p))) { \
unsigned long __gu_val; \
__chk_user_ptr(__p); \
__p = uaccess_mask_ptr(__p); \ __p = uaccess_mask_ptr(__p); \
__raw_get_user((x), __p, (err)); \ uaccess_enable_not_uao(); \
__raw_get_user(__gu_val, __p, (err)); \
uaccess_disable_not_uao(); \
(x) = (__force __typeof__(*__p)) __gu_val; \
} else { \ } else { \
(x) = 0; (err) = -EFAULT; \ (x) = 0; (err) = -EFAULT; \
} \ } \
@ -334,30 +334,26 @@ do { \
#define __raw_put_user(x, ptr, err) \ #define __raw_put_user(x, ptr, err) \
do { \ do { \
__typeof__(*(ptr)) __pu_val = (x); \
__chk_user_ptr(ptr); \
uaccess_enable_not_uao(); \
switch (sizeof(*(ptr))) { \ switch (sizeof(*(ptr))) { \
case 1: \ case 1: \
__put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \ __put_user_asm("strb", "sttrb", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \ (err), ARM64_HAS_UAO); \
break; \ break; \
case 2: \ case 2: \
__put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr), \ __put_user_asm("strh", "sttrh", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \ (err), ARM64_HAS_UAO); \
break; \ break; \
case 4: \ case 4: \
__put_user_asm("str", "sttr", "%w", __pu_val, (ptr), \ __put_user_asm("str", "sttr", "%w", (x), (ptr), \
(err), ARM64_HAS_UAO); \ (err), ARM64_HAS_UAO); \
break; \ break; \
case 8: \ case 8: \
__put_user_asm("str", "sttr", "%x", __pu_val, (ptr), \ __put_user_asm("str", "sttr", "%x", (x), (ptr), \
(err), ARM64_HAS_UAO); \ (err), ARM64_HAS_UAO); \
break; \ break; \
default: \ default: \
BUILD_BUG(); \ BUILD_BUG(); \
} \ } \
uaccess_disable_not_uao(); \
} while (0) } while (0)
#define __put_user_error(x, ptr, err) \ #define __put_user_error(x, ptr, err) \
@ -365,9 +361,13 @@ do { \
__typeof__(*(ptr)) __user *__p = (ptr); \ __typeof__(*(ptr)) __user *__p = (ptr); \
might_fault(); \ might_fault(); \
if (access_ok(__p, sizeof(*__p))) { \ if (access_ok(__p, sizeof(*__p))) { \
__typeof__(*(ptr)) __pu_val = (x); \
__chk_user_ptr(__p); \
__p = uaccess_mask_ptr(__p); \ __p = uaccess_mask_ptr(__p); \
__raw_put_user((x), __p, (err)); \ uaccess_enable_not_uao(); \
} else { \ __raw_put_user(__pu_val, __p, (err)); \
uaccess_disable_not_uao(); \
} else { \
(err) = -EFAULT; \ (err) = -EFAULT; \
} \ } \
} while (0) } while (0)
@ -381,6 +381,45 @@ do { \
#define put_user __put_user #define put_user __put_user
static __must_check inline bool user_access_begin(const void __user *ptr,
size_t len)
{
if (unlikely(!access_ok(ptr, len)))
return false;
uaccess_enable_not_uao();
return true;
}
#define user_access_begin(ptr, len) user_access_begin(ptr, len)
#define user_access_end() uaccess_disable_not_uao()
#define unsafe_get_user(x, ptr, err) \
do { \
__typeof__(*(ptr)) __user *__p = (ptr); \
unsigned long __gu_val; \
int __gu_err = 0; \
might_fault(); \
__chk_user_ptr(__p); \
__p = uaccess_mask_ptr(__p); \
__raw_get_user(__gu_val, __p, __gu_err); \
(x) = (__force __typeof__(*__p)) __gu_val; \
if (__gu_err != 0) \
goto err; \
} while (0)
#define unsafe_put_user(x, ptr, err) \
do { \
__typeof__(*(ptr)) __user *__p = (ptr); \
__typeof__(*(ptr)) __pu_val = (x); \
int __pu_err = 0; \
might_fault(); \
__chk_user_ptr(__p); \
__p = uaccess_mask_ptr(__p); \
__raw_put_user(__pu_val, __p, __pu_err); \
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); 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) \ #define raw_copy_from_user(to, from, n) \
({ \ ({ \