/* SPDX-License-Identifier: GPL-2.0 */
/* Perform sanity checking for object sizes for uaccess.h and uio.h. */
#ifndef __LINUX_UCOPYSIZE_H__
#define __LINUX_UCOPYSIZE_H__

#include <linux/bug.h>

#ifdef CONFIG_HARDENED_USERCOPY
#include <linux/jump_label.h>
extern void __check_object_size(const void *ptr, unsigned long n,
                                        bool to_user);

DECLARE_STATIC_KEY_MAYBE(CONFIG_HARDENED_USERCOPY_DEFAULT_ON,
                           validate_usercopy_range);

static __always_inline void check_object_size(const void *ptr, unsigned long n,
                                              bool to_user)
{
        if (!__builtin_constant_p(n) &&
            static_branch_maybe(CONFIG_HARDENED_USERCOPY_DEFAULT_ON,
                                &validate_usercopy_range)) {
                __check_object_size(ptr, n, to_user);
        }
}
#else
static inline void check_object_size(const void *ptr, unsigned long n,
                                     bool to_user)
{ }
#endif /* CONFIG_HARDENED_USERCOPY */

extern void __compiletime_error("copy source size is too small")
__bad_copy_from(void);
extern void __compiletime_error("copy destination size is too small")
__bad_copy_to(void);

void __copy_overflow(int size, unsigned long count);

static inline void copy_overflow(int size, unsigned long count)
{
        if (IS_ENABLED(CONFIG_BUG))
                __copy_overflow(size, count);
}

static __always_inline __must_check bool
check_copy_size(const void *addr, size_t bytes, bool is_source)
{
        int sz = __builtin_object_size(addr, 0);
        if (unlikely(sz >= 0 && sz < bytes)) {
                if (!__builtin_constant_p(bytes))
                        copy_overflow(sz, bytes);
                else if (is_source)
                        __bad_copy_from();
                else
                        __bad_copy_to();
                return false;
        }
        if (WARN_ON_ONCE(bytes > INT_MAX))
                return false;
        check_object_size(addr, bytes, is_source);
        return true;
}

#endif /* __LINUX_UCOPYSIZE_H__ */