aboutsummaryrefslogtreecommitdiff
path: root/include/linux/random.h
blob: f45b8be3e3c4e0d730834f307bbc6ca597e5ddfd (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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * include/linux/random.h
 *
 * Include file for the random number generator.
 */
#ifndef _LINUX_RANDOM_H
#define _LINUX_RANDOM_H

#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/once.h>

#include <uapi/linux/random.h>

struct random_ready_callback {
	struct list_head list;
	void (*func)(struct random_ready_callback *rdy);
	struct module *owner;
};

extern void add_device_randomness(const void *, unsigned int);
extern void add_bootloader_randomness(const void *, unsigned int);

#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
static inline void add_latent_entropy(void)
{
	add_device_randomness((const void *)&latent_entropy,
			      sizeof(latent_entropy));
}
#else
static inline void add_latent_entropy(void) {}
#endif

extern void add_input_randomness(unsigned int type, unsigned int code,
				 unsigned int value) __latent_entropy;
extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;

extern void get_random_bytes(void *buf, int nbytes);
extern int wait_for_random_bytes(void);
extern int __init rand_initialize(void);
extern bool rng_is_initialized(void);
extern int add_random_ready_callback(struct random_ready_callback *rdy);
extern void del_random_ready_callback(struct random_ready_callback *rdy);
extern int __must_check get_random_bytes_arch(void *buf, int nbytes);

#ifndef MODULE
extern const struct file_operations random_fops, urandom_fops;
#endif

u32 get_random_u32(void);
u64 get_random_u64(void);
static inline unsigned int get_random_int(void)
{
	return get_random_u32();
}
static inline unsigned long get_random_long(void)
{
#if BITS_PER_LONG == 64
	return get_random_u64();
#else
	return get_random_u32();
#endif
}

/*
 * On 64-bit architectures, protect against non-terminated C string overflows
 * by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
 */
#ifdef CONFIG_64BIT
# ifdef __LITTLE_ENDIAN
#  define CANARY_MASK 0xffffffffffffff00UL
# else /* big endian, 64 bits: */
#  define CANARY_MASK 0x00ffffffffffffffUL
# endif
#else /* 32 bits: */
# define CANARY_MASK 0xffffffffUL
#endif

static inline unsigned long get_random_canary(void)
{
	unsigned long val = get_random_long();

	return val & CANARY_MASK;
}

/* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
 * Returns the result of the call to wait_for_random_bytes. */
static inline int get_random_bytes_wait(void *buf, int nbytes)
{
	int ret = wait_for_random_bytes();
	get_random_bytes(buf, nbytes);
	return ret;
}

#define declare_get_random_var_wait(var) \
	static inline int get_random_ ## var ## _wait(var *out) { \
		int ret = wait_for_random_bytes(); \
		if (unlikely(ret)) \
			return ret; \
		*out = get_random_ ## var(); \
		return 0; \
	}
declare_get_random_var_wait(u32)
declare_get_random_var_wait(u64)
declare_get_random_var_wait(int)
declare_get_random_var_wait(long)
#undef declare_get_random_var

unsigned long randomize_page(unsigned long start, unsigned long range);

/*
 * This is designed to be standalone for just prandom
 * users, but for now we include it from <linux/random.h>
 * for legacy reasons.
 */
#include <linux/prandom.h>

#ifdef CONFIG_ARCH_RANDOM
# include <asm/archrandom.h>
#else
static inline bool __must_check arch_get_random_long(unsigned long *v)
{
	return false;
}
static inline bool __must_check arch_get_random_int(unsigned int *v)
{
	return false;
}
static inline bool __must_check arch_get_random_seed_long(unsigned long *v)
{
	return false;
}
static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
{
	return false;
}
#endif

/*
 * Called from the boot CPU during startup; not valid to call once
 * secondary CPUs are up and preemption is possible.
 */
#ifndef arch_get_random_seed_long_early
static inline bool __init arch_get_random_seed_long_early(unsigned long *v)
{
	WARN_ON(system_state != SYSTEM_BOOTING);
	return arch_get_random_seed_long(v);
}
#endif

#ifndef arch_get_random_long_early
static inline bool __init arch_get_random_long_early(unsigned long *v)
{
	WARN_ON(system_state != SYSTEM_BOOTING);
	return arch_get_random_long(v);
}
#endif

#endif /* _LINUX_RANDOM_H */