12700c17fc
There are many different ways that access_ok() is defined across architectures, but in the end, they all just compare against the user_addr_max() value or they accept anything. Provide one definition that works for most architectures, checking against TASK_SIZE_MAX for user processes or skipping the check inside of uaccess_kernel() sections. For architectures without CONFIG_SET_FS(), this should be the fastest check, as it comes down to a single comparison of a pointer against a compile-time constant, while the architecture specific versions tend to do something more complex for historic reasons or get something wrong. Type checking for __user annotations is handled inconsistently across architectures, but this is easily simplified as well by using an inline function that takes a 'const void __user *' argument. A handful of callers need an extra __user annotation for this. Some architectures had trick to use 33-bit or 65-bit arithmetic on the addresses to calculate the overflow, however this simpler version uses fewer registers, which means it can produce better object code in the end despite needing a second (statically predicted) branch. Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64, asm-generic] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Stafford Horne <shorne@gmail.com> Acked-by: Dinh Nguyen <dinguyen@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
63 lines
2.0 KiB
C
63 lines
2.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
|
|
* Copyright (C) 2015 Richard Weinberger (richard@nod.at)
|
|
*/
|
|
|
|
#ifndef __UM_UACCESS_H
|
|
#define __UM_UACCESS_H
|
|
|
|
#include <asm/elf.h>
|
|
#include <asm/unaligned.h>
|
|
|
|
#define __under_task_size(addr, size) \
|
|
(((unsigned long) (addr) < TASK_SIZE) && \
|
|
(((unsigned long) (addr) + (size)) < TASK_SIZE))
|
|
|
|
#define __access_ok_vsyscall(addr, size) \
|
|
(((unsigned long) (addr) >= FIXADDR_USER_START) && \
|
|
((unsigned long) (addr) + (size) <= FIXADDR_USER_END) && \
|
|
((unsigned long) (addr) + (size) >= (unsigned long)(addr)))
|
|
|
|
#define __addr_range_nowrap(addr, size) \
|
|
((unsigned long) (addr) <= ((unsigned long) (addr) + (size)))
|
|
|
|
extern unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n);
|
|
extern unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n);
|
|
extern unsigned long __clear_user(void __user *mem, unsigned long len);
|
|
static inline int __access_ok(const void __user *ptr, unsigned long size);
|
|
|
|
/* Teach asm-generic/uaccess.h that we have C functions for these. */
|
|
#define __access_ok __access_ok
|
|
#define __clear_user __clear_user
|
|
|
|
#define INLINE_COPY_FROM_USER
|
|
#define INLINE_COPY_TO_USER
|
|
|
|
#include <asm-generic/uaccess.h>
|
|
|
|
static inline int __access_ok(const void __user *ptr, unsigned long size)
|
|
{
|
|
unsigned long addr = (unsigned long)ptr;
|
|
return __addr_range_nowrap(addr, size) &&
|
|
(__under_task_size(addr, size) ||
|
|
__access_ok_vsyscall(addr, size));
|
|
}
|
|
|
|
/* no pagefaults for kernel addresses in um */
|
|
#define __get_kernel_nofault(dst, src, type, err_label) \
|
|
do { \
|
|
*((type *)dst) = get_unaligned((type *)(src)); \
|
|
if (0) /* make sure the label looks used to the compiler */ \
|
|
goto err_label; \
|
|
} while (0)
|
|
|
|
#define __put_kernel_nofault(dst, src, type, err_label) \
|
|
do { \
|
|
put_unaligned(*((type *)src), (type *)(dst)); \
|
|
if (0) /* make sure the label looks used to the compiler */ \
|
|
goto err_label; \
|
|
} while (0)
|
|
|
|
#endif
|