809 lines
24 KiB
C
809 lines
24 KiB
C
#ifndef _ASM_X86_UACCESS_H
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#define _ASM_X86_UACCESS_H
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/*
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* User space memory access functions
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*/
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#include <linux/errno.h>
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#include <linux/compiler.h>
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#include <linux/thread_info.h>
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#include <linux/string.h>
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#include <asm/asm.h>
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#include <asm/page.h>
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#include <asm/smap.h>
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#define VERIFY_READ 0
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#define VERIFY_WRITE 1
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/*
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* The fs value determines whether argument validity checking should be
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* performed or not. If get_fs() == USER_DS, checking is performed, with
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* get_fs() == KERNEL_DS, checking is bypassed.
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*
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* For historical reasons, these macros are grossly misnamed.
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*/
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#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
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#define KERNEL_DS MAKE_MM_SEG(-1UL)
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#define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX)
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#define get_ds() (KERNEL_DS)
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#define get_fs() (current_thread_info()->addr_limit)
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#define set_fs(x) (current_thread_info()->addr_limit = (x))
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#define segment_eq(a, b) ((a).seg == (b).seg)
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#define user_addr_max() (current_thread_info()->addr_limit.seg)
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#define __addr_ok(addr) \
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((unsigned long __force)(addr) < user_addr_max())
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/*
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* Test whether a block of memory is a valid user space address.
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* Returns 0 if the range is valid, nonzero otherwise.
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*/
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static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit)
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{
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/*
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* If we have used "sizeof()" for the size,
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* we know it won't overflow the limit (but
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* it might overflow the 'addr', so it's
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* important to subtract the size from the
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* limit, not add it to the address).
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*/
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if (__builtin_constant_p(size))
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return unlikely(addr > limit - size);
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/* Arbitrary sizes? Be careful about overflow */
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addr += size;
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if (unlikely(addr < size))
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return true;
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return unlikely(addr > limit);
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}
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#define __range_not_ok(addr, size, limit) \
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({ \
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__chk_user_ptr(addr); \
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__chk_range_not_ok((unsigned long __force)(addr), size, limit); \
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})
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/**
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* access_ok: - Checks if a user space pointer is valid
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* @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
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* %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
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* to write to a block, it is always safe to read from it.
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* @addr: User space pointer to start of block to check
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* @size: Size of block to check
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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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* Checks if a pointer to a block of memory in user space is valid.
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*
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* Returns true (nonzero) if the memory block may be valid, false (zero)
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* if it is definitely invalid.
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*
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* Note that, depending on architecture, this function probably just
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* checks that the pointer is in the user space range - after calling
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* this function, memory access functions may still return -EFAULT.
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*/
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#define access_ok(type, addr, size) \
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likely(!__range_not_ok(addr, size, user_addr_max()))
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/*
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* The exception table consists of triples of addresses relative to the
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* exception table entry itself. The first address is of an instruction
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* that is allowed to fault, the second is the target at which the program
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* should continue. The third is a handler function to deal with the fault
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* caused by the instruction in the first field.
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*
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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*/
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struct exception_table_entry {
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int insn, fixup, handler;
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};
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#define ARCH_HAS_RELATIVE_EXTABLE
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#define swap_ex_entry_fixup(a, b, tmp, delta) \
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do { \
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(a)->fixup = (b)->fixup + (delta); \
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(b)->fixup = (tmp).fixup - (delta); \
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(a)->handler = (b)->handler + (delta); \
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(b)->handler = (tmp).handler - (delta); \
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} while (0)
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extern int fixup_exception(struct pt_regs *regs, int trapnr);
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extern bool ex_has_fault_handler(unsigned long ip);
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extern int early_fixup_exception(unsigned long *ip);
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/*
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* These are the main single-value transfer routines. They automatically
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* use the right size if we just have the right pointer type.
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*
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* This gets kind of ugly. We want to return _two_ values in "get_user()"
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* and yet we don't want to do any pointers, because that is too much
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* of a performance impact. Thus we have a few rather ugly macros here,
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* and hide all the ugliness from the user.
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*
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* The "__xxx" versions of the user access functions are versions that
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* do not verify the address space, that must have been done previously
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* with a separate "access_ok()" call (this is used when we do multiple
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* accesses to the same area of user memory).
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*/
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extern int __get_user_1(void);
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extern int __get_user_2(void);
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extern int __get_user_4(void);
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extern int __get_user_8(void);
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extern int __get_user_bad(void);
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#define __uaccess_begin() stac()
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#define __uaccess_end() clac()
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/*
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* This is a type: either unsigned long, if the argument fits into
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* that type, or otherwise unsigned long long.
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*/
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#define __inttype(x) \
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__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
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/**
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* get_user: - Get a simple variable from user space.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Returns zero on success, or -EFAULT on error.
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* On error, the variable @x is set to zero.
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*/
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/*
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* Careful: we have to cast the result to the type of the pointer
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* for sign reasons.
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*
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* The use of _ASM_DX as the register specifier is a bit of a
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* simplification, as gcc only cares about it as the starting point
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* and not size: for a 64-bit value it will use %ecx:%edx on 32 bits
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* (%ecx being the next register in gcc's x86 register sequence), and
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* %rdx on 64 bits.
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*
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* Clang/LLVM cares about the size of the register, but still wants
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* the base register for something that ends up being a pair.
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*/
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#define get_user(x, ptr) \
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({ \
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int __ret_gu; \
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register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \
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register void *__sp asm(_ASM_SP); \
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__chk_user_ptr(ptr); \
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might_fault(); \
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asm volatile("call __get_user_%P4" \
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: "=a" (__ret_gu), "=r" (__val_gu), "+r" (__sp) \
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: "0" (ptr), "i" (sizeof(*(ptr)))); \
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(x) = (__force __typeof__(*(ptr))) __val_gu; \
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__builtin_expect(__ret_gu, 0); \
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})
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#define __put_user_x(size, x, ptr, __ret_pu) \
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asm volatile("call __put_user_" #size : "=a" (__ret_pu) \
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: "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
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#ifdef CONFIG_X86_32
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#define __put_user_asm_u64(x, addr, err, errret) \
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asm volatile("\n" \
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"1: movl %%eax,0(%2)\n" \
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"2: movl %%edx,4(%2)\n" \
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"3:" \
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".section .fixup,\"ax\"\n" \
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"4: movl %3,%0\n" \
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" jmp 3b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b, 4b) \
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_ASM_EXTABLE(2b, 4b) \
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: "=r" (err) \
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: "A" (x), "r" (addr), "i" (errret), "0" (err))
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#define __put_user_asm_ex_u64(x, addr) \
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asm volatile("\n" \
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"1: movl %%eax,0(%1)\n" \
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"2: movl %%edx,4(%1)\n" \
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"3:" \
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_ASM_EXTABLE_EX(1b, 2b) \
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_ASM_EXTABLE_EX(2b, 3b) \
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: : "A" (x), "r" (addr))
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#define __put_user_x8(x, ptr, __ret_pu) \
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asm volatile("call __put_user_8" : "=a" (__ret_pu) \
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: "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
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#else
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#define __put_user_asm_u64(x, ptr, retval, errret) \
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__put_user_asm(x, ptr, retval, "q", "", "er", errret)
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#define __put_user_asm_ex_u64(x, addr) \
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__put_user_asm_ex(x, addr, "q", "", "er")
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#define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
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#endif
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extern void __put_user_bad(void);
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/*
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* Strange magic calling convention: pointer in %ecx,
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* value in %eax(:%edx), return value in %eax. clobbers %rbx
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*/
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extern void __put_user_1(void);
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extern void __put_user_2(void);
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extern void __put_user_4(void);
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extern void __put_user_8(void);
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/**
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* put_user: - Write a simple value into user space.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep if pagefaults are
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* enabled.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Returns zero on success, or -EFAULT on error.
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*/
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#define put_user(x, ptr) \
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({ \
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int __ret_pu; \
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__typeof__(*(ptr)) __pu_val; \
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__chk_user_ptr(ptr); \
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might_fault(); \
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__pu_val = x; \
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switch (sizeof(*(ptr))) { \
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case 1: \
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__put_user_x(1, __pu_val, ptr, __ret_pu); \
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break; \
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case 2: \
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__put_user_x(2, __pu_val, ptr, __ret_pu); \
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break; \
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case 4: \
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__put_user_x(4, __pu_val, ptr, __ret_pu); \
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break; \
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case 8: \
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__put_user_x8(__pu_val, ptr, __ret_pu); \
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break; \
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default: \
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__put_user_x(X, __pu_val, ptr, __ret_pu); \
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break; \
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} \
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__builtin_expect(__ret_pu, 0); \
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})
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#define __put_user_size(x, ptr, size, retval, errret) \
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do { \
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retval = 0; \
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__chk_user_ptr(ptr); \
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switch (size) { \
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case 1: \
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__put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \
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break; \
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case 2: \
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__put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \
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break; \
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case 4: \
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__put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \
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break; \
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case 8: \
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__put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval, \
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errret); \
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break; \
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default: \
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__put_user_bad(); \
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} \
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} while (0)
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/*
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* This doesn't do __uaccess_begin/end - the exception handling
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* around it must do that.
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*/
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#define __put_user_size_ex(x, ptr, size) \
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do { \
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__chk_user_ptr(ptr); \
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switch (size) { \
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case 1: \
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__put_user_asm_ex(x, ptr, "b", "b", "iq"); \
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break; \
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case 2: \
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__put_user_asm_ex(x, ptr, "w", "w", "ir"); \
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break; \
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case 4: \
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__put_user_asm_ex(x, ptr, "l", "k", "ir"); \
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break; \
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case 8: \
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__put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \
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break; \
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default: \
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__put_user_bad(); \
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} \
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} while (0)
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#ifdef CONFIG_X86_32
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#define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad()
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#define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad()
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#else
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#define __get_user_asm_u64(x, ptr, retval, errret) \
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__get_user_asm(x, ptr, retval, "q", "", "=r", errret)
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#define __get_user_asm_ex_u64(x, ptr) \
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__get_user_asm_ex(x, ptr, "q", "", "=r")
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#endif
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#define __get_user_size(x, ptr, size, retval, errret) \
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do { \
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retval = 0; \
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__chk_user_ptr(ptr); \
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switch (size) { \
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case 1: \
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__get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
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break; \
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case 2: \
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__get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
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break; \
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case 4: \
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__get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \
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break; \
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case 8: \
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__get_user_asm_u64(x, ptr, retval, errret); \
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break; \
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default: \
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(x) = __get_user_bad(); \
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} \
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} while (0)
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#define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \
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asm volatile("\n" \
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"1: mov"itype" %2,%"rtype"1\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: mov %3,%0\n" \
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" xor"itype" %"rtype"1,%"rtype"1\n" \
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" jmp 2b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b, 3b) \
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: "=r" (err), ltype(x) \
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: "m" (__m(addr)), "i" (errret), "0" (err))
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/*
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* This doesn't do __uaccess_begin/end - the exception handling
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* around it must do that.
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*/
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#define __get_user_size_ex(x, ptr, size) \
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do { \
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__chk_user_ptr(ptr); \
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switch (size) { \
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case 1: \
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__get_user_asm_ex(x, ptr, "b", "b", "=q"); \
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break; \
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case 2: \
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__get_user_asm_ex(x, ptr, "w", "w", "=r"); \
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break; \
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case 4: \
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__get_user_asm_ex(x, ptr, "l", "k", "=r"); \
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break; \
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case 8: \
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__get_user_asm_ex_u64(x, ptr); \
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break; \
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default: \
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(x) = __get_user_bad(); \
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} \
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} while (0)
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#define __get_user_asm_ex(x, addr, itype, rtype, ltype) \
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asm volatile("1: mov"itype" %1,%"rtype"0\n" \
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"2:\n" \
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_ASM_EXTABLE_EX(1b, 2b) \
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: ltype(x) : "m" (__m(addr)))
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#define __put_user_nocheck(x, ptr, size) \
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({ \
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int __pu_err; \
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__uaccess_begin(); \
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__put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \
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__uaccess_end(); \
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__builtin_expect(__pu_err, 0); \
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})
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#define __get_user_nocheck(x, ptr, size) \
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({ \
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int __gu_err; \
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unsigned long __gu_val; \
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__uaccess_begin(); \
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__get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
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__uaccess_end(); \
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(x) = (__force __typeof__(*(ptr)))__gu_val; \
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__builtin_expect(__gu_err, 0); \
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})
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/* FIXME: this hack is definitely wrong -AK */
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struct __large_struct { unsigned long buf[100]; };
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#define __m(x) (*(struct __large_struct __user *)(x))
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/*
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* Tell gcc we read from memory instead of writing: this is because
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* we do not write to any memory gcc knows about, so there are no
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* aliasing issues.
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*/
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#define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \
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asm volatile("\n" \
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"1: mov"itype" %"rtype"1,%2\n" \
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"2:\n" \
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".section .fixup,\"ax\"\n" \
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"3: mov %3,%0\n" \
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" jmp 2b\n" \
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".previous\n" \
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_ASM_EXTABLE(1b, 3b) \
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: "=r"(err) \
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: ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
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#define __put_user_asm_ex(x, addr, itype, rtype, ltype) \
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asm volatile("1: mov"itype" %"rtype"0,%1\n" \
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"2:\n" \
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_ASM_EXTABLE_EX(1b, 2b) \
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: : ltype(x), "m" (__m(addr)))
|
|
|
|
/*
|
|
* uaccess_try and catch
|
|
*/
|
|
#define uaccess_try do { \
|
|
current_thread_info()->uaccess_err = 0; \
|
|
__uaccess_begin(); \
|
|
barrier();
|
|
|
|
#define uaccess_catch(err) \
|
|
__uaccess_end(); \
|
|
(err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0); \
|
|
} while (0)
|
|
|
|
/**
|
|
* __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.
|
|
*
|
|
* Returns 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.
|
|
*
|
|
* Returns zero on success, or -EFAULT on error.
|
|
*/
|
|
|
|
#define __put_user(x, ptr) \
|
|
__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
|
|
|
|
#define __get_user_unaligned __get_user
|
|
#define __put_user_unaligned __put_user
|
|
|
|
/*
|
|
* {get|put}_user_try and catch
|
|
*
|
|
* get_user_try {
|
|
* get_user_ex(...);
|
|
* } get_user_catch(err)
|
|
*/
|
|
#define get_user_try uaccess_try
|
|
#define get_user_catch(err) uaccess_catch(err)
|
|
|
|
#define get_user_ex(x, ptr) do { \
|
|
unsigned long __gue_val; \
|
|
__get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr)))); \
|
|
(x) = (__force __typeof__(*(ptr)))__gue_val; \
|
|
} while (0)
|
|
|
|
#define put_user_try uaccess_try
|
|
#define put_user_catch(err) uaccess_catch(err)
|
|
|
|
#define put_user_ex(x, ptr) \
|
|
__put_user_size_ex((__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 strlen_user(const char __user *str);
|
|
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);
|
|
|
|
extern void __cmpxchg_wrong_size(void)
|
|
__compiletime_error("Bad argument size for cmpxchg");
|
|
|
|
#define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size) \
|
|
({ \
|
|
int __ret = 0; \
|
|
__typeof__(ptr) __uval = (uval); \
|
|
__typeof__(*(ptr)) __old = (old); \
|
|
__typeof__(*(ptr)) __new = (new); \
|
|
__uaccess_begin(); \
|
|
switch (size) { \
|
|
case 1: \
|
|
{ \
|
|
asm volatile("\n" \
|
|
"1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n" \
|
|
"2:\n" \
|
|
"\t.section .fixup, \"ax\"\n" \
|
|
"3:\tmov %3, %0\n" \
|
|
"\tjmp 2b\n" \
|
|
"\t.previous\n" \
|
|
_ASM_EXTABLE(1b, 3b) \
|
|
: "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
|
|
: "i" (-EFAULT), "q" (__new), "1" (__old) \
|
|
: "memory" \
|
|
); \
|
|
break; \
|
|
} \
|
|
case 2: \
|
|
{ \
|
|
asm volatile("\n" \
|
|
"1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n" \
|
|
"2:\n" \
|
|
"\t.section .fixup, \"ax\"\n" \
|
|
"3:\tmov %3, %0\n" \
|
|
"\tjmp 2b\n" \
|
|
"\t.previous\n" \
|
|
_ASM_EXTABLE(1b, 3b) \
|
|
: "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
|
|
: "i" (-EFAULT), "r" (__new), "1" (__old) \
|
|
: "memory" \
|
|
); \
|
|
break; \
|
|
} \
|
|
case 4: \
|
|
{ \
|
|
asm volatile("\n" \
|
|
"1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" \
|
|
"2:\n" \
|
|
"\t.section .fixup, \"ax\"\n" \
|
|
"3:\tmov %3, %0\n" \
|
|
"\tjmp 2b\n" \
|
|
"\t.previous\n" \
|
|
_ASM_EXTABLE(1b, 3b) \
|
|
: "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
|
|
: "i" (-EFAULT), "r" (__new), "1" (__old) \
|
|
: "memory" \
|
|
); \
|
|
break; \
|
|
} \
|
|
case 8: \
|
|
{ \
|
|
if (!IS_ENABLED(CONFIG_X86_64)) \
|
|
__cmpxchg_wrong_size(); \
|
|
\
|
|
asm volatile("\n" \
|
|
"1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n" \
|
|
"2:\n" \
|
|
"\t.section .fixup, \"ax\"\n" \
|
|
"3:\tmov %3, %0\n" \
|
|
"\tjmp 2b\n" \
|
|
"\t.previous\n" \
|
|
_ASM_EXTABLE(1b, 3b) \
|
|
: "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
|
|
: "i" (-EFAULT), "r" (__new), "1" (__old) \
|
|
: "memory" \
|
|
); \
|
|
break; \
|
|
} \
|
|
default: \
|
|
__cmpxchg_wrong_size(); \
|
|
} \
|
|
__uaccess_end(); \
|
|
*__uval = __old; \
|
|
__ret; \
|
|
})
|
|
|
|
#define user_atomic_cmpxchg_inatomic(uval, ptr, old, new) \
|
|
({ \
|
|
access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \
|
|
__user_atomic_cmpxchg_inatomic((uval), (ptr), \
|
|
(old), (new), sizeof(*(ptr))) : \
|
|
-EFAULT; \
|
|
})
|
|
|
|
/*
|
|
* 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
|
|
|
|
unsigned long __must_check _copy_from_user(void *to, const void __user *from,
|
|
unsigned n);
|
|
unsigned long __must_check _copy_to_user(void __user *to, const void *from,
|
|
unsigned n);
|
|
|
|
#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
|
|
# define copy_user_diag __compiletime_error
|
|
#else
|
|
# define copy_user_diag __compiletime_warning
|
|
#endif
|
|
|
|
extern void copy_user_diag("copy_from_user() buffer size is too small")
|
|
copy_from_user_overflow(void);
|
|
extern void copy_user_diag("copy_to_user() buffer size is too small")
|
|
copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
|
|
|
|
#undef copy_user_diag
|
|
|
|
#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
|
|
|
|
extern void
|
|
__compiletime_warning("copy_from_user() buffer size is not provably correct")
|
|
__copy_from_user_overflow(void) __asm__("copy_from_user_overflow");
|
|
#define __copy_from_user_overflow(size, count) __copy_from_user_overflow()
|
|
|
|
extern void
|
|
__compiletime_warning("copy_to_user() buffer size is not provably correct")
|
|
__copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
|
|
#define __copy_to_user_overflow(size, count) __copy_to_user_overflow()
|
|
|
|
#else
|
|
|
|
static inline void
|
|
__copy_from_user_overflow(int size, unsigned long count)
|
|
{
|
|
WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
|
|
}
|
|
|
|
#define __copy_to_user_overflow __copy_from_user_overflow
|
|
|
|
#endif
|
|
|
|
static inline unsigned long __must_check
|
|
copy_from_user(void *to, const void __user *from, unsigned long n)
|
|
{
|
|
int sz = __compiletime_object_size(to);
|
|
|
|
might_fault();
|
|
|
|
/*
|
|
* While we would like to have the compiler do the checking for us
|
|
* even in the non-constant size case, any false positives there are
|
|
* a problem (especially when DEBUG_STRICT_USER_COPY_CHECKS, but even
|
|
* without - the [hopefully] dangerous looking nature of the warning
|
|
* would make people go look at the respecitive call sites over and
|
|
* over again just to find that there's no problem).
|
|
*
|
|
* And there are cases where it's just not realistic for the compiler
|
|
* to prove the count to be in range. For example when multiple call
|
|
* sites of a helper function - perhaps in different source files -
|
|
* all doing proper range checking, yet the helper function not doing
|
|
* so again.
|
|
*
|
|
* Therefore limit the compile time checking to the constant size
|
|
* case, and do only runtime checking for non-constant sizes.
|
|
*/
|
|
|
|
if (likely(sz < 0 || sz >= n))
|
|
n = _copy_from_user(to, from, n);
|
|
else if(__builtin_constant_p(n))
|
|
copy_from_user_overflow();
|
|
else
|
|
__copy_from_user_overflow(sz, n);
|
|
|
|
return n;
|
|
}
|
|
|
|
static inline unsigned long __must_check
|
|
copy_to_user(void __user *to, const void *from, unsigned long n)
|
|
{
|
|
int sz = __compiletime_object_size(from);
|
|
|
|
might_fault();
|
|
|
|
/* See the comment in copy_from_user() above. */
|
|
if (likely(sz < 0 || sz >= n))
|
|
n = _copy_to_user(to, from, n);
|
|
else if(__builtin_constant_p(n))
|
|
copy_to_user_overflow();
|
|
else
|
|
__copy_to_user_overflow(sz, n);
|
|
|
|
return n;
|
|
}
|
|
|
|
#undef __copy_from_user_overflow
|
|
#undef __copy_to_user_overflow
|
|
|
|
/*
|
|
* We rely on the nested NMI work to allow atomic faults from the NMI path; the
|
|
* nested NMI paths are careful to preserve CR2.
|
|
*
|
|
* Caller must use pagefault_enable/disable, or run in interrupt context,
|
|
* and also do a uaccess_ok() check
|
|
*/
|
|
#define __copy_from_user_nmi __copy_from_user_inatomic
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
#define user_access_begin() __uaccess_begin()
|
|
#define user_access_end() __uaccess_end()
|
|
|
|
#define unsafe_put_user(x, ptr) \
|
|
({ \
|
|
int __pu_err; \
|
|
__put_user_size((x), (ptr), sizeof(*(ptr)), __pu_err, -EFAULT); \
|
|
__builtin_expect(__pu_err, 0); \
|
|
})
|
|
|
|
#define unsafe_get_user(x, ptr) \
|
|
({ \
|
|
int __gu_err; \
|
|
unsigned long __gu_val; \
|
|
__get_user_size(__gu_val, (ptr), sizeof(*(ptr)), __gu_err, -EFAULT); \
|
|
(x) = (__force __typeof__(*(ptr)))__gu_val; \
|
|
__builtin_expect(__gu_err, 0); \
|
|
})
|
|
|
|
#endif /* _ASM_X86_UACCESS_H */
|
|
|