| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef _ASM_X86_UACCESS_H |
| #define _ASM_X86_UACCESS_H |
| /* |
| * User space memory access functions |
| */ |
| #include <linux/compiler.h> |
| #include <linux/kasan-checks.h> |
| #include <linux/string.h> |
| #include <asm/asm.h> |
| #include <asm/page.h> |
| #include <asm/smap.h> |
| #include <asm/extable.h> |
| |
| /* |
| * The fs value determines whether argument validity checking should be |
| * performed or not. If get_fs() == USER_DS, checking is performed, with |
| * get_fs() == KERNEL_DS, checking is bypassed. |
| * |
| * For historical reasons, these macros are grossly misnamed. |
| */ |
| |
| #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) |
| |
| #define KERNEL_DS MAKE_MM_SEG(-1UL) |
| #define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX) |
| |
| #define get_fs() (current->thread.addr_limit) |
| static inline void set_fs(mm_segment_t fs) |
| { |
| current->thread.addr_limit = fs; |
| /* On user-mode return, check fs is correct */ |
| set_thread_flag(TIF_FSCHECK); |
| } |
| |
| #define segment_eq(a, b) ((a).seg == (b).seg) |
| #define user_addr_max() (current->thread.addr_limit.seg) |
| |
| /* |
| * Test whether a block of memory is a valid user space address. |
| * Returns 0 if the range is valid, nonzero otherwise. |
| */ |
| static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit) |
| { |
| /* |
| * If we have used "sizeof()" for the size, |
| * we know it won't overflow the limit (but |
| * it might overflow the 'addr', so it's |
| * important to subtract the size from the |
| * limit, not add it to the address). |
| */ |
| if (__builtin_constant_p(size)) |
| return unlikely(addr > limit - size); |
| |
| /* Arbitrary sizes? Be careful about overflow */ |
| addr += size; |
| if (unlikely(addr < size)) |
| return true; |
| return unlikely(addr > limit); |
| } |
| |
| #define __range_not_ok(addr, size, limit) \ |
| ({ \ |
| __chk_user_ptr(addr); \ |
| __chk_range_not_ok((unsigned long __force)(addr), size, limit); \ |
| }) |
| |
| #ifdef CONFIG_DEBUG_ATOMIC_SLEEP |
| static inline bool pagefault_disabled(void); |
| # define WARN_ON_IN_IRQ() \ |
| WARN_ON_ONCE(!in_task() && !pagefault_disabled()) |
| #else |
| # define WARN_ON_IN_IRQ() |
| #endif |
| |
| /** |
| * access_ok - Checks if a user space pointer is valid |
| * @addr: User space pointer to start of block to check |
| * @size: Size of block to check |
| * |
| * Context: User context only. This function may sleep if pagefaults are |
| * enabled. |
| * |
| * Checks if a pointer to a block of memory in user space is valid. |
| * |
| * Note that, depending on architecture, this function probably just |
| * checks that the pointer is in the user space range - after calling |
| * this function, memory access functions may still return -EFAULT. |
| * |
| * Return: true (nonzero) if the memory block may be valid, false (zero) |
| * if it is definitely invalid. |
| */ |
| #define access_ok(addr, size) \ |
| ({ \ |
| WARN_ON_IN_IRQ(); \ |
| likely(!__range_not_ok(addr, size, user_addr_max())); \ |
| }) |
| |
| /* |
| * These are the main single-value transfer routines. They automatically |
| * use the right size if we just have the right pointer type. |
| * |
| * This gets kind of ugly. We want to return _two_ values in "get_user()" |
| * and yet we don't want to do any pointers, because that is too much |
| * of a performance impact. Thus we have a few rather ugly macros here, |
| * and hide all the ugliness from the user. |
| * |
| * The "__xxx" versions of the user access functions are versions that |
| * do not verify the address space, that must have been done previously |
| * with a separate "access_ok()" call (this is used when we do multiple |
| * accesses to the same area of user memory). |
| */ |
| |
| extern int __get_user_1(void); |
| extern int __get_user_2(void); |
| extern int __get_user_4(void); |
| extern int __get_user_8(void); |
| extern int __get_user_bad(void); |
| |
| #define __uaccess_begin() stac() |
| #define __uaccess_end() clac() |
| #define __uaccess_begin_nospec() \ |
| ({ \ |
| stac(); \ |
| barrier_nospec(); \ |
| }) |
| |
| /* |
| * This is the smallest unsigned integer type that can fit a value |
| * (up to 'long long') |
| */ |
| #define __inttype(x) __typeof__( \ |
| __typefits(x,char, \ |
| __typefits(x,short, \ |
| __typefits(x,int, \ |
| __typefits(x,long,0ULL))))) |
| |
| #define __typefits(x,type,not) \ |
| __builtin_choose_expr(sizeof(x)<=sizeof(type),(unsigned type)0,not) |
| |
| /** |
| * get_user - Get a simple variable from user space. |
| * @x: Variable to store result. |
| * @ptr: Source address, in user space. |
| * |
| * Context: User context only. This function may sleep if pagefaults are |
| * enabled. |
| * |
| * This macro copies a single simple variable from user space to kernel |
| * space. It supports simple types like char and int, but not larger |
| * data types like structures or arrays. |
| * |
| * @ptr must have pointer-to-simple-variable type, and the result of |
| * dereferencing @ptr must be assignable to @x without a cast. |
| * |
| * Return: zero on success, or -EFAULT on error. |
| * On error, the variable @x is set to zero. |
| */ |
| /* |
| * Careful: we have to cast the result to the type of the pointer |
| * for sign reasons. |
| * |
| * The use of _ASM_DX as the register specifier is a bit of a |
| * simplification, as gcc only cares about it as the starting point |
| * and not size: for a 64-bit value it will use %ecx:%edx on 32 bits |
| * (%ecx being the next register in gcc's x86 register sequence), and |
| * %rdx on 64 bits. |
| * |
| * Clang/LLVM cares about the size of the register, but still wants |
| * the base register for something that ends up being a pair. |
| */ |
| #define get_user(x, ptr) \ |
| ({ \ |
| int __ret_gu; \ |
| register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \ |
| __chk_user_ptr(ptr); \ |
| might_fault(); \ |
| asm volatile("call __get_user_%P4" \ |
| : "=a" (__ret_gu), "=r" (__val_gu), \ |
| ASM_CALL_CONSTRAINT \ |
| : "0" (ptr), "i" (sizeof(*(ptr)))); \ |
| (x) = (__force __typeof__(*(ptr))) __val_gu; \ |
| __builtin_expect(__ret_gu, 0); \ |
| }) |
| |
| #define __put_user_x(size, x, ptr, __ret_pu) \ |
| asm volatile("call __put_user_" #size : "=a" (__ret_pu) \ |
| : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") |
| |
| |
| |
| #ifdef CONFIG_X86_32 |
| #define __put_user_goto_u64(x, addr, label) \ |
| asm_volatile_goto("\n" \ |
| "1: movl %%eax,0(%1)\n" \ |
| "2: movl %%edx,4(%1)\n" \ |
| _ASM_EXTABLE_UA(1b, %l2) \ |
| _ASM_EXTABLE_UA(2b, %l2) \ |
| : : "A" (x), "r" (addr) \ |
| : : label) |
| |
| #define __put_user_x8(x, ptr, __ret_pu) \ |
| asm volatile("call __put_user_8" : "=a" (__ret_pu) \ |
| : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") |
| #else |
| #define __put_user_goto_u64(x, ptr, label) \ |
| __put_user_goto(x, ptr, "q", "er", label) |
| #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu) |
| #endif |
| |
| extern void __put_user_bad(void); |
| |
| /* |
| * Strange magic calling convention: pointer in %ecx, |
| * value in %eax(:%edx), return value in %eax. clobbers %rbx |
| */ |
| extern void __put_user_1(void); |
| extern void __put_user_2(void); |
| extern void __put_user_4(void); |
| extern void __put_user_8(void); |
| |
| /** |
| * put_user - Write a simple value into user space. |
| * @x: Value to copy to user space. |
| * @ptr: Destination address, in user space. |
| * |
| * Context: User context only. This function may sleep if pagefaults are |
| * enabled. |
| * |
| * This macro copies a single simple value from kernel space to user |
| * space. It supports simple types like char and int, but not larger |
| * data types like structures or arrays. |
| * |
| * @ptr must have pointer-to-simple-variable type, and @x must be assignable |
| * to the result of dereferencing @ptr. |
| * |
| * Return: zero on success, or -EFAULT on error. |
| */ |
| #define put_user(x, ptr) \ |
| ({ \ |
| int __ret_pu; \ |
| __typeof__(*(ptr)) __pu_val; \ |
| __chk_user_ptr(ptr); \ |
| might_fault(); \ |
| __pu_val = x; \ |
| switch (sizeof(*(ptr))) { \ |
| case 1: \ |
| __put_user_x(1, __pu_val, ptr, __ret_pu); \ |
| break; \ |
| case 2: \ |
| __put_user_x(2, __pu_val, ptr, __ret_pu); \ |
| break; \ |
| case 4: \ |
| __put_user_x(4, __pu_val, ptr, __ret_pu); \ |
| break; \ |
| case 8: \ |
| __put_user_x8(__pu_val, ptr, __ret_pu); \ |
| break; \ |
| default: \ |
| __put_user_x(X, __pu_val, ptr, __ret_pu); \ |
| break; \ |
| } \ |
| __builtin_expect(__ret_pu, 0); \ |
| }) |
| |
| #define __put_user_size(x, ptr, size, label) \ |
| do { \ |
| __chk_user_ptr(ptr); \ |
| switch (size) { \ |
| case 1: \ |
| __put_user_goto(x, ptr, "b", "iq", label); \ |
| break; \ |
| case 2: \ |
| __put_user_goto(x, ptr, "w", "ir", label); \ |
| break; \ |
| case 4: \ |
| __put_user_goto(x, ptr, "l", "ir", label); \ |
| break; \ |
| case 8: \ |
| __put_user_goto_u64(x, ptr, label); \ |
| break; \ |
| default: \ |
| __put_user_bad(); \ |
| } \ |
| } while (0) |
| |
| #ifdef CONFIG_X86_32 |
| #define __get_user_asm_u64(x, ptr, retval) \ |
| ({ \ |
| __typeof__(ptr) __ptr = (ptr); \ |
| asm volatile("\n" \ |
| "1: movl %[lowbits],%%eax\n" \ |
| "2: movl %[highbits],%%edx\n" \ |
| "3:\n" \ |
| ".section .fixup,\"ax\"\n" \ |
| "4: mov %[efault],%[errout]\n" \ |
| " xorl %%eax,%%eax\n" \ |
| " xorl %%edx,%%edx\n" \ |
| " jmp 3b\n" \ |
| ".previous\n" \ |
| _ASM_EXTABLE_UA(1b, 4b) \ |
| _ASM_EXTABLE_UA(2b, 4b) \ |
| : [errout] "=r" (retval), \ |
| [output] "=&A"(x) \ |
| : [lowbits] "m" (__m(__ptr)), \ |
| [highbits] "m" __m(((u32 __user *)(__ptr)) + 1), \ |
| [efault] "i" (-EFAULT), "0" (retval)); \ |
| }) |
| |
| #else |
| #define __get_user_asm_u64(x, ptr, retval) \ |
| __get_user_asm(x, ptr, retval, "q", "=r") |
| #endif |
| |
| #define __get_user_size(x, ptr, size, retval) \ |
| do { \ |
| retval = 0; \ |
| __chk_user_ptr(ptr); \ |
| switch (size) { \ |
| case 1: \ |
| __get_user_asm(x, ptr, retval, "b", "=q"); \ |
| break; \ |
| case 2: \ |
| __get_user_asm(x, ptr, retval, "w", "=r"); \ |
| break; \ |
| case 4: \ |
| __get_user_asm(x, ptr, retval, "l", "=r"); \ |
| break; \ |
| case 8: \ |
| __get_user_asm_u64(x, ptr, retval); \ |
| break; \ |
| default: \ |
| (x) = __get_user_bad(); \ |
| } \ |
| } while (0) |
| |
| #define __get_user_asm(x, addr, err, itype, ltype) \ |
| asm volatile("\n" \ |
| "1: mov"itype" %[umem],%[output]\n" \ |
| "2:\n" \ |
| ".section .fixup,\"ax\"\n" \ |
| "3: mov %[efault],%[errout]\n" \ |
| " xor"itype" %[output],%[output]\n" \ |
| " jmp 2b\n" \ |
| ".previous\n" \ |
| _ASM_EXTABLE_UA(1b, 3b) \ |
| : [errout] "=r" (err), \ |
| [output] ltype(x) \ |
| : [umem] "m" (__m(addr)), \ |
| [efault] "i" (-EFAULT), "0" (err)) |
| |
| #define __put_user_nocheck(x, ptr, size) \ |
| ({ \ |
| __label__ __pu_label; \ |
| int __pu_err = -EFAULT; \ |
| __typeof__(*(ptr)) __pu_val = (x); \ |
| __typeof__(ptr) __pu_ptr = (ptr); \ |
| __typeof__(size) __pu_size = (size); \ |
| __uaccess_begin(); \ |
| __put_user_size(__pu_val, __pu_ptr, __pu_size, __pu_label); \ |
| __pu_err = 0; \ |
| __pu_label: \ |
| __uaccess_end(); \ |
| __builtin_expect(__pu_err, 0); \ |
| }) |
| |
| #define __get_user_nocheck(x, ptr, size) \ |
| ({ \ |
| int __gu_err; \ |
| __inttype(*(ptr)) __gu_val; \ |
| __typeof__(ptr) __gu_ptr = (ptr); \ |
| __typeof__(size) __gu_size = (size); \ |
| __uaccess_begin_nospec(); \ |
| __get_user_size(__gu_val, __gu_ptr, __gu_size, __gu_err); \ |
| __uaccess_end(); \ |
| (x) = (__force __typeof__(*(ptr)))__gu_val; \ |
| __builtin_expect(__gu_err, 0); \ |
| }) |
| |
| /* FIXME: this hack is definitely wrong -AK */ |
| struct __large_struct { unsigned long buf[100]; }; |
| #define __m(x) (*(struct __large_struct __user *)(x)) |
| |
| /* |
| * Tell gcc we read from memory instead of writing: this is because |
| * we do not write to any memory gcc knows about, so there are no |
| * aliasing issues. |
| */ |
| #define __put_user_goto(x, addr, itype, ltype, label) \ |
| asm_volatile_goto("\n" \ |
| "1: mov"itype" %0,%1\n" \ |
| _ASM_EXTABLE_UA(1b, %l2) \ |
| : : ltype(x), "m" (__m(addr)) \ |
| : : label) |
| |
| /** |
| * __get_user - Get a simple variable from user space, with less checking. |
| * @x: Variable to store result. |
| * @ptr: Source address, in user space. |
| * |
| * Context: User context only. This function may sleep if pagefaults are |
| * enabled. |
| * |
| * This macro copies a single simple variable from user space to kernel |
| * space. It supports simple types like char and int, but not larger |
| * data types like structures or arrays. |
| * |
| * @ptr must have pointer-to-simple-variable type, and the result of |
| * dereferencing @ptr must be assignable to @x without a cast. |
| * |
| * Caller must check the pointer with access_ok() before calling this |
| * function. |
| * |
| * Return: zero on success, or -EFAULT on error. |
| * On error, the variable @x is set to zero. |
| */ |
| |
| #define __get_user(x, ptr) \ |
| __get_user_nocheck((x), (ptr), sizeof(*(ptr))) |
| |
| /** |
| * __put_user - Write a simple value into user space, with less checking. |
| * @x: Value to copy to user space. |
| * @ptr: Destination address, in user space. |
| * |
| * Context: User context only. This function may sleep if pagefaults are |
| * enabled. |
| * |
| * This macro copies a single simple value from kernel space to user |
| * space. It supports simple types like char and int, but not larger |
| * data types like structures or arrays. |
| * |
| * @ptr must have pointer-to-simple-variable type, and @x must be assignable |
| * to the result of dereferencing @ptr. |
| * |
| * Caller must check the pointer with access_ok() before calling this |
| * function. |
| * |
| * Return: zero on success, or -EFAULT on error. |
| */ |
| |
| #define __put_user(x, ptr) \ |
| __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) |
| |
| extern unsigned long |
| copy_from_user_nmi(void *to, const void __user *from, unsigned long n); |
| extern __must_check long |
| strncpy_from_user(char *dst, const char __user *src, long count); |
| |
| extern __must_check long strnlen_user(const char __user *str, long n); |
| |
| unsigned long __must_check clear_user(void __user *mem, unsigned long len); |
| unsigned long __must_check __clear_user(void __user *mem, unsigned long len); |
| |
| /* |
| * movsl can be slow when source and dest are not both 8-byte aligned |
| */ |
| #ifdef CONFIG_X86_INTEL_USERCOPY |
| extern struct movsl_mask { |
| int mask; |
| } ____cacheline_aligned_in_smp movsl_mask; |
| #endif |
| |
| #define ARCH_HAS_NOCACHE_UACCESS 1 |
| |
| #ifdef CONFIG_X86_32 |
| # include <asm/uaccess_32.h> |
| #else |
| # include <asm/uaccess_64.h> |
| #endif |
| |
| /* |
| * The "unsafe" user accesses aren't really "unsafe", but the naming |
| * is a big fat warning: you have to not only do the access_ok() |
| * checking before using them, but you have to surround them with the |
| * user_access_begin/end() pair. |
| */ |
| static __must_check __always_inline bool user_access_begin(const void __user *ptr, size_t len) |
| { |
| if (unlikely(!access_ok(ptr,len))) |
| return 0; |
| __uaccess_begin_nospec(); |
| return 1; |
| } |
| #define user_access_begin(a,b) user_access_begin(a,b) |
| #define user_access_end() __uaccess_end() |
| |
| #define user_access_save() smap_save() |
| #define user_access_restore(x) smap_restore(x) |
| |
| #define unsafe_put_user(x, ptr, label) \ |
| __put_user_size((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)), label) |
| |
| #define unsafe_get_user(x, ptr, err_label) \ |
| do { \ |
| int __gu_err; \ |
| __inttype(*(ptr)) __gu_val; \ |
| __get_user_size(__gu_val, (ptr), sizeof(*(ptr)), __gu_err); \ |
| (x) = (__force __typeof__(*(ptr)))__gu_val; \ |
| if (unlikely(__gu_err)) goto err_label; \ |
| } while (0) |
| |
| /* |
| * We want the unsafe accessors to always be inlined and use |
| * the error labels - thus the macro games. |
| */ |
| #define unsafe_copy_loop(dst, src, len, type, label) \ |
| while (len >= sizeof(type)) { \ |
| unsafe_put_user(*(type *)(src),(type __user *)(dst),label); \ |
| dst += sizeof(type); \ |
| src += sizeof(type); \ |
| len -= sizeof(type); \ |
| } |
| |
| #define unsafe_copy_to_user(_dst,_src,_len,label) \ |
| do { \ |
| char __user *__ucu_dst = (_dst); \ |
| const char *__ucu_src = (_src); \ |
| size_t __ucu_len = (_len); \ |
| unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u64, label); \ |
| unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u32, label); \ |
| unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u16, label); \ |
| unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \ |
| } while (0) |
| |
| #define HAVE_GET_KERNEL_NOFAULT |
| |
| #define __get_kernel_nofault(dst, src, type, err_label) \ |
| do { \ |
| int __kr_err; \ |
| \ |
| __get_user_size(*((type *)(dst)), (__force type __user *)(src), \ |
| sizeof(type), __kr_err); \ |
| if (unlikely(__kr_err)) \ |
| goto err_label; \ |
| } while (0) |
| |
| #define __put_kernel_nofault(dst, src, type, err_label) \ |
| __put_user_size(*((type *)(src)), (__force type __user *)(dst), \ |
| sizeof(type), err_label) |
| |
| #endif /* _ASM_X86_UACCESS_H */ |
| |