lib/usercopy.c

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