summaryrefslogtreecommitdiff
path: root/include/linux/sockptr.h
blob: 7d5cdb2b30b5f02ce6516892acc88cf394884a68 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (c) 2020 Christoph Hellwig.
 *
 * Support for "universal" pointers that can point to either kernel or userspace
 * memory.
 */
#ifndef _LINUX_SOCKPTR_H
#define _LINUX_SOCKPTR_H

#include <linux/compiler.h>
#include <linux/slab.h>
#include <linux/uaccess.h>

#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
typedef union {
	void		*kernel;
	void __user	*user;
} sockptr_t;

static inline bool sockptr_is_kernel(sockptr_t sockptr)
{
	return (unsigned long)sockptr.kernel >= TASK_SIZE;
}

static inline sockptr_t KERNEL_SOCKPTR(void *p)
{
	return (sockptr_t) { .kernel = p };
}

static inline int __must_check init_user_sockptr(sockptr_t *sp, void __user *p)
{
	if ((unsigned long)p >= TASK_SIZE)
		return -EFAULT;
	sp->user = p;
	return 0;
}
#else /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */
typedef struct {
	union {
		void		*kernel;
		void __user	*user;
	};
	bool		is_kernel : 1;
} sockptr_t;

static inline bool sockptr_is_kernel(sockptr_t sockptr)
{
	return sockptr.is_kernel;
}

static inline sockptr_t KERNEL_SOCKPTR(void *p)
{
	return (sockptr_t) { .kernel = p, .is_kernel = true };
}

static inline int __must_check init_user_sockptr(sockptr_t *sp, void __user *p)
{
	sp->user = p;
	sp->is_kernel = false;
	return 0;
}
#endif /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */

static inline bool sockptr_is_null(sockptr_t sockptr)
{
	return !sockptr.user && !sockptr.kernel;
}

static inline int copy_from_sockptr(void *dst, sockptr_t src, size_t size)
{
	if (!sockptr_is_kernel(src))
		return copy_from_user(dst, src.user, size);
	memcpy(dst, src.kernel, size);
	return 0;
}

static inline int copy_to_sockptr(sockptr_t dst, const void *src, size_t size)
{
	if (!sockptr_is_kernel(dst))
		return copy_to_user(dst.user, src, size);
	memcpy(dst.kernel, src, size);
	return 0;
}

static inline void *memdup_sockptr(sockptr_t src, size_t len)
{
	void *p = kmalloc_track_caller(len, GFP_USER | __GFP_NOWARN);

	if (!p)
		return ERR_PTR(-ENOMEM);
	if (copy_from_sockptr(p, src, len)) {
		kfree(p);
		return ERR_PTR(-EFAULT);
	}
	return p;
}

static inline void *memdup_sockptr_nul(sockptr_t src, size_t len)
{
	char *p = kmalloc_track_caller(len + 1, GFP_KERNEL);

	if (!p)
		return ERR_PTR(-ENOMEM);
	if (copy_from_sockptr(p, src, len)) {
		kfree(p);
		return ERR_PTR(-EFAULT);
	}
	p[len] = '\0';
	return p;
}

static inline void sockptr_advance(sockptr_t sockptr, size_t len)
{
	if (sockptr_is_kernel(sockptr))
		sockptr.kernel += len;
	else
		sockptr.user += len;
}

static inline long strncpy_from_sockptr(char *dst, sockptr_t src, size_t count)
{
	if (sockptr_is_kernel(src)) {
		size_t len = min(strnlen(src.kernel, count - 1) + 1, count);

		memcpy(dst, src.kernel, len);
		return len;
	}
	return strncpy_from_user(dst, src.user, count);
}

#endif /* _LINUX_SOCKPTR_H */