1#include <linux/export.h>
2#include <linux/bug.h>
3#include <linux/uaccess.h>
 
4
5void copy_from_user_overflow(void)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6{
7	WARN(1, "Buffer overflow detected!\n");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8}
9EXPORT_SYMBOL(copy_from_user_overflow);

 1// SPDX-License-Identifier: GPL-2.0
 
 2#include <linux/uaccess.h>
 3#include <linux/bitops.h>
 4
 5/* out-of-line parts */
 6
 7#ifndef INLINE_COPY_FROM_USER
 8unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n)
 9{
10	unsigned long res = n;
11	might_fault();
12	if (likely(access_ok(from, n))) {
13		kasan_check_write(to, n);
14		res = raw_copy_from_user(to, from, n);
15	}
16	if (unlikely(res))
17		memset(to + (n - res), 0, res);
18	return res;
19}
20EXPORT_SYMBOL(_copy_from_user);
21#endif
22
23#ifndef INLINE_COPY_TO_USER
24unsigned long _copy_to_user(void __user *to, const void *from, unsigned long n)
25{
26	might_fault();
27	if (likely(access_ok(to, n))) {
28		kasan_check_read(from, n);
29		n = raw_copy_to_user(to, from, n);
30	}
31	return n;
32}
33EXPORT_SYMBOL(_copy_to_user);
34#endif
35
36/**
37 * check_zeroed_user: check if a userspace buffer only contains zero bytes
38 * @from: Source address, in userspace.
39 * @size: Size of buffer.
40 *
41 * This is effectively shorthand for "memchr_inv(from, 0, size) == NULL" for
42 * userspace addresses (and is more efficient because we don't care where the
43 * first non-zero byte is).
44 *
45 * Returns:
46 *  * 0: There were non-zero bytes present in the buffer.
47 *  * 1: The buffer was full of zero bytes.
48 *  * -EFAULT: access to userspace failed.
49 */
50int check_zeroed_user(const void __user *from, size_t size)
51{
52	unsigned long val;
53	uintptr_t align = (uintptr_t) from % sizeof(unsigned long);
54
55	if (unlikely(size == 0))
56		return 1;
57
58	from -= align;
59	size += align;
60
61	if (!user_access_begin(from, size))
62		return -EFAULT;
63
64	unsafe_get_user(val, (unsigned long __user *) from, err_fault);
65	if (align)
66		val &= ~aligned_byte_mask(align);
67
68	while (size > sizeof(unsigned long)) {
69		if (unlikely(val))
70			goto done;
71
72		from += sizeof(unsigned long);
73		size -= sizeof(unsigned long);
74
75		unsafe_get_user(val, (unsigned long __user *) from, err_fault);
76	}
77
78	if (size < sizeof(unsigned long))
79		val &= aligned_byte_mask(size);
80
81done:
82	user_access_end();
83	return (val == 0);
84err_fault:
85	user_access_end();
86	return -EFAULT;
87}
88EXPORT_SYMBOL(check_zeroed_user);