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 <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> --- arch/arm64/include/asm/uaccess.h | 79 ++++++++++++++++++++++++++++++---------- 1 file changed, 59 insertions(+), 20 deletions(-) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 8e40808..6a70c75 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -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 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) __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 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) #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) \ @@ -365,9 +361,13 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) __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)); \ - } else { \ + uaccess_enable_not_uao(); \ + __raw_put_user(__pu_val, __p, (err)); \ + uaccess_disable_not_uao(); \ + } else { \ (err) = -EFAULT; \ } \ } while (0) @@ -381,6 +381,45 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr) #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) \ ({ \ -- 1.9.1
