Commit 0bd3ef34 authored by Julien Thierry's avatar Julien Thierry Committed by Catalin Marinas
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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.

Signed-off-by: default avatarJulien Thierry <julien.thierry@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 13e4cdd7

arch/arm64/include/asm/uaccess.h

+59 −20
Original line number Diff line number Diff line
@@ -270,31 +270,26 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) 


#define __raw_get_user(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),  \

		__get_user_asm("ldrb", "ldtrb", "%w", (x), (ptr),	\

			       (err), ARM64_HAS_UAO);			\

		break;							\

	case 2:								\

		__get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr),  \

		__get_user_asm("ldrh", "ldtrh", "%w", (x), (ptr),	\

			       (err), ARM64_HAS_UAO);			\

		break;							\

	case 4:								\

		__get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr),	\

		__get_user_asm("ldr", "ldtr", "%w", (x), (ptr),		\

			       (err), ARM64_HAS_UAO);			\

		break;							\

	case 8:								\

		__get_user_asm("ldr", "ldtr", "%x",  __gu_val, (ptr),	\

		__get_user_asm("ldr", "ldtr", "%x",  (x), (ptr),	\

			       (err), ARM64_HAS_UAO);			\

		break;							\

	default:							\

		BUILD_BUG();						\

	}								\

	uaccess_disable_not_uao();					\

	(x) = (__force __typeof__(*(ptr)))__gu_val;			\

} while (0)



#define __get_user_error(x, ptr, err)					\
@@ -302,8 +297,13 @@ do { \ 
	__typeof__(*(ptr)) __user *__p = (ptr);				\

	might_fault();							\

	if (access_ok(__p, sizeof(*__p))) {				\

		unsigned long __gu_val;					\

		__chk_user_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 {							\

		(x) = 0; (err) = -EFAULT;				\

	}								\
@@ -334,30 +334,26 @@ do { \ 


#define __raw_put_user(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),	\

		__put_user_asm("strb", "sttrb", "%w", (x), (ptr),	\

			       (err), ARM64_HAS_UAO);			\

		break;							\

	case 2:								\

		__put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr),	\

		__put_user_asm("strh", "sttrh", "%w", (x), (ptr),	\

			       (err), ARM64_HAS_UAO);			\

		break;							\

	case 4:								\

		__put_user_asm("str", "sttr", "%w", __pu_val, (ptr),	\

		__put_user_asm("str", "sttr", "%w", (x), (ptr),		\

			       (err), ARM64_HAS_UAO);			\

		break;							\

	case 8:								\

		__put_user_asm("str", "sttr", "%x", __pu_val, (ptr),	\

		__put_user_asm("str", "sttr", "%x", (x), (ptr),		\

			       (err), ARM64_HAS_UAO);			\

		break;							\

	default:							\

		BUILD_BUG();						\

	}								\

	uaccess_disable_not_uao();					\

} while (0)



#define __put_user_error(x, ptr, err)					\
@@ -365,8 +361,12 @@ do { \ 
	__typeof__(*(ptr)) __user *__p = (ptr);				\

	might_fault();							\

	if (access_ok(__p, sizeof(*__p))) {				\

		__typeof__(*(ptr)) __pu_val = (x);			\

		__chk_user_ptr(__p);					\

		__p = uaccess_mask_ptr(__p);				\

		__raw_put_user((x), __p, (err));			\

		uaccess_enable_not_uao();				\

		__raw_put_user(__pu_val, __p, (err));			\

		uaccess_disable_not_uao();				\

	} else {							\

		(err) = -EFAULT;					\

	}								\
@@ -381,6 +381,45 @@ do { \ 


#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);

#define raw_copy_from_user(to, from, n)					\

({									\

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