--- /dev/null
+#ifndef _ASM_X86_UACCESS_H
+#define _ASM_X86_UACCESS_H
+/*
+ * User space memory access functions
+ */
+#include <linux/errno.h>
+#include <linux/compiler.h>
+#include <linux/thread_info.h>
+#include <linux/string.h>
+#include <asm/asm.h>
+#include <asm/page.h>
+#include <asm/smap.h>
+
+#define VERIFY_READ 0
+#define VERIFY_WRITE 1
+
+/*
+ * 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_ds() (KERNEL_DS)
+#define get_fs() (current_thread_info()->addr_limit)
+#define set_fs(x) (current_thread_info()->addr_limit = (x))
+
+#define segment_eq(a, b) ((a).seg == (b).seg)
+
+#define user_addr_max() (current_thread_info()->addr_limit.seg)
+#define __addr_ok(addr) \
+ ((unsigned long __force)(addr) < user_addr_max())
+
+/*
+ * 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 addr > limit - size;
+
+ /* Arbitrary sizes? Be careful about overflow */
+ addr += size;
+ if (addr < size)
+ return true;
+ return addr > limit;
+}
+
+#define __range_not_ok(addr, size, limit) \
+({ \
+ __chk_user_ptr(addr); \
+ __chk_range_not_ok((unsigned long __force)(addr), size, limit); \
+})
+
+/**
+ * access_ok: - Checks if a user space pointer is valid
+ * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
+ * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
+ * to write to a block, it is always safe to read from it.
+ * @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.
+ *
+ * Returns true (nonzero) if the memory block may be valid, false (zero)
+ * if it is definitely invalid.
+ *
+ * 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.
+ */
+#define access_ok(type, addr, size) \
+ likely(!__range_not_ok(addr, size, user_addr_max()))
+
+/*
+ * The exception table consists of pairs of addresses relative to the
+ * exception table enty itself: the first is the address of an
+ * instruction that is allowed to fault, and the second is the address
+ * at which the program should continue. No registers are modified,
+ * so it is entirely up to the continuation code to figure out what to
+ * do.
+ *
+ * All the routines below use bits of fixup code that are out of line
+ * with the main instruction path. This means when everything is well,
+ * we don't even have to jump over them. Further, they do not intrude
+ * on our cache or tlb entries.
+ */
+
+struct exception_table_entry {
+ int insn, fixup;
+};
+/* This is not the generic standard exception_table_entry format */
+#define ARCH_HAS_SORT_EXTABLE
+#define ARCH_HAS_SEARCH_EXTABLE
+
+extern int fixup_exception(struct pt_regs *regs);
+extern int early_fixup_exception(unsigned long *ip);
+
+/*
+ * 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);
+
+/*
+ * This is a type: either unsigned long, if the argument fits into
+ * that type, or otherwise unsigned long long.
+ */
+#define __inttype(x) \
+__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
+
+/**
+ * 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.
+ *
+ * Returns 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_%P3" \
+ : "=a" (__ret_gu), "=r" (__val_gu) \
+ : "0" (ptr), "i" (sizeof(*(ptr)))); \
+ (x) = (__force __typeof__(*(ptr))) __val_gu; \
+ __ret_gu; \
+})
+
+#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_asm_u64(x, addr, err, errret) \
+ asm volatile(ASM_STAC "\n" \
+ "1: movl %%eax,0(%2)\n" \
+ "2: movl %%edx,4(%2)\n" \
+ "3: " ASM_CLAC "\n" \
+ ".section .fixup,\"ax\"\n" \
+ "4: movl %3,%0\n" \
+ " jmp 3b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE(1b, 4b) \
+ _ASM_EXTABLE(2b, 4b) \
+ : "=r" (err) \
+ : "A" (x), "r" (addr), "i" (errret), "0" (err))
+
+#define __put_user_asm_ex_u64(x, addr) \
+ asm volatile(ASM_STAC "\n" \
+ "1: movl %%eax,0(%1)\n" \
+ "2: movl %%edx,4(%1)\n" \
+ "3: " ASM_CLAC "\n" \
+ _ASM_EXTABLE_EX(1b, 2b) \
+ _ASM_EXTABLE_EX(2b, 3b) \
+ : : "A" (x), "r" (addr))
+
+#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_asm_u64(x, ptr, retval, errret) \
+ __put_user_asm(x, ptr, retval, "q", "", "er", errret)
+#define __put_user_asm_ex_u64(x, addr) \
+ __put_user_asm_ex(x, addr, "q", "", "er")
+#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.
+ *
+ * Returns 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; \
+ } \
+ __ret_pu; \
+})
+
+#define __put_user_size(x, ptr, size, retval, errret) \
+do { \
+ retval = 0; \
+ __chk_user_ptr(ptr); \
+ switch (size) { \
+ case 1: \
+ __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \
+ break; \
+ case 2: \
+ __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \
+ break; \
+ case 4: \
+ __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \
+ break; \
+ case 8: \
+ __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval, \
+ errret); \
+ break; \
+ default: \
+ __put_user_bad(); \
+ } \
+} while (0)
+
+#define __put_user_size_ex(x, ptr, size) \
+do { \
+ __chk_user_ptr(ptr); \
+ switch (size) { \
+ case 1: \
+ __put_user_asm_ex(x, ptr, "b", "b", "iq"); \
+ break; \
+ case 2: \
+ __put_user_asm_ex(x, ptr, "w", "w", "ir"); \
+ break; \
+ case 4: \
+ __put_user_asm_ex(x, ptr, "l", "k", "ir"); \
+ break; \
+ case 8: \
+ __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \
+ break; \
+ default: \
+ __put_user_bad(); \
+ } \
+} while (0)
+
+#ifdef CONFIG_X86_32
+#define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad()
+#define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad()
+#else
+#define __get_user_asm_u64(x, ptr, retval, errret) \
+ __get_user_asm(x, ptr, retval, "q", "", "=r", errret)
+#define __get_user_asm_ex_u64(x, ptr) \
+ __get_user_asm_ex(x, ptr, "q", "", "=r")
+#endif
+
+#define __get_user_size(x, ptr, size, retval, errret) \
+do { \
+ retval = 0; \
+ __chk_user_ptr(ptr); \
+ switch (size) { \
+ case 1: \
+ __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
+ break; \
+ case 2: \
+ __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
+ break; \
+ case 4: \
+ __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \
+ break; \
+ case 8: \
+ __get_user_asm_u64(x, ptr, retval, errret); \
+ break; \
+ default: \
+ (x) = __get_user_bad(); \
+ } \
+} while (0)
+
+#define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \
+ asm volatile(ASM_STAC "\n" \
+ "1: mov"itype" %2,%"rtype"1\n" \
+ "2: " ASM_CLAC "\n" \
+ ".section .fixup,\"ax\"\n" \
+ "3: mov %3,%0\n" \
+ " xor"itype" %"rtype"1,%"rtype"1\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE(1b, 3b) \
+ : "=r" (err), ltype(x) \
+ : "m" (__m(addr)), "i" (errret), "0" (err))
+
+#define __get_user_size_ex(x, ptr, size) \
+do { \
+ __chk_user_ptr(ptr); \
+ switch (size) { \
+ case 1: \
+ __get_user_asm_ex(x, ptr, "b", "b", "=q"); \
+ break; \
+ case 2: \
+ __get_user_asm_ex(x, ptr, "w", "w", "=r"); \
+ break; \
+ case 4: \
+ __get_user_asm_ex(x, ptr, "l", "k", "=r"); \
+ break; \
+ case 8: \
+ __get_user_asm_ex_u64(x, ptr); \
+ break; \
+ default: \
+ (x) = __get_user_bad(); \
+ } \
+} while (0)
+
+#define __get_user_asm_ex(x, addr, itype, rtype, ltype) \
+ asm volatile("1: mov"itype" %1,%"rtype"0\n" \
+ "2:\n" \
+ _ASM_EXTABLE_EX(1b, 2b) \
+ : ltype(x) : "m" (__m(addr)))
+
+#define __put_user_nocheck(x, ptr, size) \
+({ \
+ int __pu_err; \
+ __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \
+ __pu_err; \
+})
+
+#define __get_user_nocheck(x, ptr, size) \
+({ \
+ int __gu_err; \
+ unsigned long __gu_val; \
+ __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
+ (x) = (__force __typeof__(*(ptr)))__gu_val; \
+ __gu_err; \
+})
+
+/* 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_asm(x, addr, err, itype, rtype, ltype, errret) \
+ asm volatile(ASM_STAC "\n" \
+ "1: mov"itype" %"rtype"1,%2\n" \
+ "2: " ASM_CLAC "\n" \
+ ".section .fixup,\"ax\"\n" \
+ "3: mov %3,%0\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE(1b, 3b) \
+ : "=r"(err) \
+ : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
+
+#define __put_user_asm_ex(x, addr, itype, rtype, ltype) \
+ asm volatile("1: mov"itype" %"rtype"0,%1\n" \
+ "2:\n" \
+ _ASM_EXTABLE_EX(1b, 2b) \
+ : : ltype(x), "m" (__m(addr)))
+
+/*
+ * uaccess_try and catch
+ */
+#define uaccess_try do { \
+ current_thread_info()->uaccess_err = 0; \
+ stac(); \
+ barrier();
+
+#define uaccess_catch(err) \
+ clac(); \
+ (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); \
+ switch (size) { \
+ case 1: \
+ { \
+ asm volatile("\t" ASM_STAC "\n" \
+ "1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n" \
+ "2:\t" ASM_CLAC "\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("\t" ASM_STAC "\n" \
+ "1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n" \
+ "2:\t" ASM_CLAC "\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("\t" ASM_STAC "\n" \
+ "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" \
+ "2:\t" ASM_CLAC "\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("\t" ASM_STAC "\n" \
+ "1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n" \
+ "2:\t" ASM_CLAC "\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(); \
+ } \
+ *__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
+
+#endif /* _ASM_X86_UACCESS_H */
+
Code Review / kvmfornfv.git / blobdiff