linux/arch/s390/include/asm/uaccess.h
Heiko Carstens 1dcec254af [S390] uaccess: implement strict user copy checks
Same as on x86 and sparc, besides the fact that enabling the option
will just emit compile time warnings instead of errors.
Keeps allyesconfig kernels compiling.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-02-26 22:37:29 +01:00

377 lines
10 KiB
C

/*
* include/asm-s390/uaccess.h
*
* S390 version
* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Hartmut Penner (hp@de.ibm.com),
* Martin Schwidefsky (schwidefsky@de.ibm.com)
*
* Derived from "include/asm-i386/uaccess.h"
*/
#ifndef __S390_UACCESS_H
#define __S390_UACCESS_H
/*
* User space memory access functions
*/
#include <linux/sched.h>
#include <linux/errno.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(a) ((mm_segment_t) { (a) })
#define KERNEL_DS MAKE_MM_SEG(0)
#define USER_DS MAKE_MM_SEG(1)
#define get_ds() (KERNEL_DS)
#define get_fs() (current->thread.mm_segment)
#define set_fs(x) \
({ \
unsigned long __pto; \
current->thread.mm_segment = (x); \
__pto = current->thread.mm_segment.ar4 ? \
S390_lowcore.user_asce : S390_lowcore.kernel_asce; \
__ctl_load(__pto, 7, 7); \
})
#define segment_eq(a,b) ((a).ar4 == (b).ar4)
static inline int __access_ok(const void __user *addr, unsigned long size)
{
return 1;
}
#define access_ok(type,addr,size) __access_ok(addr,size)
/*
* The exception table consists of pairs of addresses: 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
{
unsigned long insn, fixup;
};
struct uaccess_ops {
size_t (*copy_from_user)(size_t, const void __user *, void *);
size_t (*copy_from_user_small)(size_t, const void __user *, void *);
size_t (*copy_to_user)(size_t, void __user *, const void *);
size_t (*copy_to_user_small)(size_t, void __user *, const void *);
size_t (*copy_in_user)(size_t, void __user *, const void __user *);
size_t (*clear_user)(size_t, void __user *);
size_t (*strnlen_user)(size_t, const char __user *);
size_t (*strncpy_from_user)(size_t, const char __user *, char *);
int (*futex_atomic_op)(int op, int __user *, int oparg, int *old);
int (*futex_atomic_cmpxchg)(int __user *, int old, int new);
};
extern struct uaccess_ops uaccess;
extern struct uaccess_ops uaccess_std;
extern struct uaccess_ops uaccess_mvcos;
extern struct uaccess_ops uaccess_mvcos_switch;
extern struct uaccess_ops uaccess_pt;
extern int __handle_fault(unsigned long, unsigned long, int);
static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
{
size = uaccess.copy_to_user_small(size, ptr, x);
return size ? -EFAULT : size;
}
static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
{
size = uaccess.copy_from_user_small(size, ptr, x);
return size ? -EFAULT : size;
}
/*
* These are the main single-value transfer routines. They automatically
* use the right size if we just have the right pointer type.
*/
#define __put_user(x, ptr) \
({ \
__typeof__(*(ptr)) __x = (x); \
int __pu_err = -EFAULT; \
__chk_user_ptr(ptr); \
switch (sizeof (*(ptr))) { \
case 1: \
case 2: \
case 4: \
case 8: \
__pu_err = __put_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
break; \
default: \
__put_user_bad(); \
break; \
} \
__pu_err; \
})
#define put_user(x, ptr) \
({ \
might_fault(); \
__put_user(x, ptr); \
})
extern int __put_user_bad(void) __attribute__((noreturn));
#define __get_user(x, ptr) \
({ \
int __gu_err = -EFAULT; \
__chk_user_ptr(ptr); \
switch (sizeof(*(ptr))) { \
case 1: { \
unsigned char __x; \
__gu_err = __get_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
case 2: { \
unsigned short __x; \
__gu_err = __get_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
case 4: { \
unsigned int __x; \
__gu_err = __get_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
case 8: { \
unsigned long long __x; \
__gu_err = __get_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
(x) = *(__force __typeof__(*(ptr)) *) &__x; \
break; \
}; \
default: \
__get_user_bad(); \
break; \
} \
__gu_err; \
})
#define get_user(x, ptr) \
({ \
might_fault(); \
__get_user(x, ptr); \
})
extern int __get_user_bad(void) __attribute__((noreturn));
#define __put_user_unaligned __put_user
#define __get_user_unaligned __get_user
/**
* __copy_to_user: - Copy a block of data into user space, with less checking.
* @to: Destination address, in user space.
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from kernel space to user space. Caller must check
* the specified block with access_ok() before calling this function.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*/
static inline unsigned long __must_check
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (__builtin_constant_p(n) && (n <= 256))
return uaccess.copy_to_user_small(n, to, from);
else
return uaccess.copy_to_user(n, to, from);
}
#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user
/**
* copy_to_user: - Copy a block of data into user space.
* @to: Destination address, in user space.
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from kernel space to user space.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*/
static inline unsigned long __must_check
copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_fault();
if (access_ok(VERIFY_WRITE, to, n))
n = __copy_to_user(to, from, n);
return n;
}
/**
* __copy_from_user: - Copy a block of data from user space, with less checking.
* @to: Destination address, in kernel space.
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from user space to kernel space. Caller must check
* the specified block with access_ok() before calling this function.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*
* If some data could not be copied, this function will pad the copied
* data to the requested size using zero bytes.
*/
static inline unsigned long __must_check
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (__builtin_constant_p(n) && (n <= 256))
return uaccess.copy_from_user_small(n, from, to);
else
return uaccess.copy_from_user(n, from, to);
}
extern void copy_from_user_overflow(void)
#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
__compiletime_warning("copy_from_user() buffer size is not provably correct")
#endif
;
/**
* copy_from_user: - Copy a block of data from user space.
* @to: Destination address, in kernel space.
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from user space to kernel space.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*
* If some data could not be copied, this function will pad the copied
* data to the requested size using zero bytes.
*/
static inline unsigned long __must_check
copy_from_user(void *to, const void __user *from, unsigned long n)
{
unsigned int sz = __compiletime_object_size(to);
might_fault();
if (unlikely(sz != -1 && sz < n)) {
copy_from_user_overflow();
return n;
}
if (access_ok(VERIFY_READ, from, n))
n = __copy_from_user(to, from, n);
else
memset(to, 0, n);
return n;
}
static inline unsigned long __must_check
__copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
return uaccess.copy_in_user(n, to, from);
}
static inline unsigned long __must_check
copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
might_fault();
if (__access_ok(from,n) && __access_ok(to,n))
n = __copy_in_user(to, from, n);
return n;
}
/*
* Copy a null terminated string from userspace.
*/
static inline long __must_check
strncpy_from_user(char *dst, const char __user *src, long count)
{
long res = -EFAULT;
might_fault();
if (access_ok(VERIFY_READ, src, 1))
res = uaccess.strncpy_from_user(count, src, dst);
return res;
}
static inline unsigned long
strnlen_user(const char __user * src, unsigned long n)
{
might_fault();
return uaccess.strnlen_user(n, src);
}
/**
* strlen_user: - Get the size of a string in user space.
* @str: The string to measure.
*
* Context: User context only. This function may sleep.
*
* Get the size of a NUL-terminated string in user space.
*
* Returns the size of the string INCLUDING the terminating NUL.
* On exception, returns 0.
*
* If there is a limit on the length of a valid string, you may wish to
* consider using strnlen_user() instead.
*/
#define strlen_user(str) strnlen_user(str, ~0UL)
/*
* Zero Userspace
*/
static inline unsigned long __must_check
__clear_user(void __user *to, unsigned long n)
{
return uaccess.clear_user(n, to);
}
static inline unsigned long __must_check
clear_user(void __user *to, unsigned long n)
{
might_fault();
if (access_ok(VERIFY_WRITE, to, n))
n = uaccess.clear_user(n, to);
return n;
}
#endif /* __S390_UACCESS_H */