lib/usercopy.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/uaccess.h>
   3
   4 /* out-of-line parts */
   5
   6 #ifndef INLINE_COPY_FROM_USER
   7 unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n)
   8 {
   9         unsigned long res = n;
  10         might_fault();
  11         if (likely(access_ok(VERIFY_READ, from, n))) {
  12                 kasan_check_write(to, n);
  13                 res = raw_copy_from_user(to, from, n);
  14         }
  15         if (unlikely(res))
  16                 memset(to + (n - res), 0, res);
  17         return res;
  18 }
  19 EXPORT_SYMBOL(_copy_from_user);
  20 #endif
  21
  22 #ifndef INLINE_COPY_TO_USER
  23 unsigned long _copy_to_user(void *to, const void __user *from, unsigned long n)
  24 {
  25         might_fault();
  26         if (likely(access_ok(VERIFY_WRITE, to, n))) {
  27                 kasan_check_read(from, n);
  28                 n = raw_copy_to_user(to, from, n);
  29         }
  30         return n;
  31 }
  32 EXPORT_SYMBOL(_copy_to_user);
  33 #endif