1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/compiler.h>
3 #include <linux/errno.h>
4 #include <linux/export.h>
5 #include <linux/fault-inject-usercopy.h>
6 #include <linux/instrumented.h>
7 #include <linux/kernel.h>
8 #include <linux/nospec.h>
9 #include <linux/string.h>
10 #include <linux/uaccess.h>
11 #include <linux/wordpart.h>
13 /* out-of-line parts */
15 #if !defined(INLINE_COPY_FROM_USER) || defined(CONFIG_RUST)
16 unsigned long _copy_from_user(void *to
, const void __user
*from
, unsigned long n
)
18 return _inline_copy_from_user(to
, from
, n
);
20 EXPORT_SYMBOL(_copy_from_user
);
23 #if !defined(INLINE_COPY_TO_USER) || defined(CONFIG_RUST)
24 unsigned long _copy_to_user(void __user
*to
, const void *from
, unsigned long n
)
26 return _inline_copy_to_user(to
, from
, n
);
28 EXPORT_SYMBOL(_copy_to_user
);
32 * check_zeroed_user: check if a userspace buffer only contains zero bytes
33 * @from: Source address, in userspace.
34 * @size: Size of buffer.
36 * This is effectively shorthand for "memchr_inv(from, 0, size) == NULL" for
37 * userspace addresses (and is more efficient because we don't care where the
38 * first non-zero byte is).
41 * * 0: There were non-zero bytes present in the buffer.
42 * * 1: The buffer was full of zero bytes.
43 * * -EFAULT: access to userspace failed.
45 int check_zeroed_user(const void __user
*from
, size_t size
)
48 uintptr_t align
= (uintptr_t) from
% sizeof(unsigned long);
50 if (unlikely(size
== 0))
56 if (!user_read_access_begin(from
, size
))
59 unsafe_get_user(val
, (unsigned long __user
*) from
, err_fault
);
61 val
&= ~aligned_byte_mask(align
);
63 while (size
> sizeof(unsigned long)) {
67 from
+= sizeof(unsigned long);
68 size
-= sizeof(unsigned long);
70 unsafe_get_user(val
, (unsigned long __user
*) from
, err_fault
);
73 if (size
< sizeof(unsigned long))
74 val
&= aligned_byte_mask(size
);
77 user_read_access_end();
80 user_read_access_end();
83 EXPORT_SYMBOL(check_zeroed_user
);