1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/bitops.h>
 3#include <linux/fault-inject-usercopy.h>
 4#include <linux/instrumented.h>
 5#include <linux/uaccess.h>
 
 6
 7/* out-of-line parts */
 8
 9#ifndef INLINE_COPY_FROM_USER
10unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n)
11{
12	unsigned long res = n;
13	might_fault();
14	if (!should_fail_usercopy() && likely(access_ok(from, n))) {
15		instrument_copy_from_user(to, from, n);
16		res = raw_copy_from_user(to, from, n);
17	}
18	if (unlikely(res))
19		memset(to + (n - res), 0, res);
20	return res;
21}
22EXPORT_SYMBOL(_copy_from_user);
23#endif
24
25#ifndef INLINE_COPY_TO_USER
26unsigned long _copy_to_user(void __user *to, const void *from, unsigned long n)
27{
28	might_fault();
29	if (should_fail_usercopy())
30		return n;
31	if (likely(access_ok(to, n))) {
32		instrument_copy_to_user(to, from, n);
33		n = raw_copy_to_user(to, from, n);
34	}
35	return n;
36}
37EXPORT_SYMBOL(_copy_to_user);
38#endif
39
40/**
41 * check_zeroed_user: check if a userspace buffer only contains zero bytes
42 * @from: Source address, in userspace.
43 * @size: Size of buffer.
44 *
45 * This is effectively shorthand for "memchr_inv(from, 0, size) == NULL" for
46 * userspace addresses (and is more efficient because we don't care where the
47 * first non-zero byte is).
48 *
49 * Returns:
50 *  * 0: There were non-zero bytes present in the buffer.
51 *  * 1: The buffer was full of zero bytes.
52 *  * -EFAULT: access to userspace failed.
53 */
54int check_zeroed_user(const void __user *from, size_t size)
55{
56	unsigned long val;
57	uintptr_t align = (uintptr_t) from % sizeof(unsigned long);
58
59	if (unlikely(size == 0))
60		return 1;
61
62	from -= align;
63	size += align;
64
65	if (!user_read_access_begin(from, size))
66		return -EFAULT;
67
68	unsafe_get_user(val, (unsigned long __user *) from, err_fault);
69	if (align)
70		val &= ~aligned_byte_mask(align);
71
72	while (size > sizeof(unsigned long)) {
73		if (unlikely(val))
74			goto done;
75
76		from += sizeof(unsigned long);
77		size -= sizeof(unsigned long);
78
79		unsafe_get_user(val, (unsigned long __user *) from, err_fault);
80	}
81
82	if (size < sizeof(unsigned long))
83		val &= aligned_byte_mask(size);
84
85done:
86	user_read_access_end();
87	return (val == 0);
88err_fault:
89	user_read_access_end();
90	return -EFAULT;
91}
92EXPORT_SYMBOL(check_zeroed_user);

 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);