aboutsummaryrefslogtreecommitdiff
path: root/include/linux/random.h
blob: 147a5e0d0b8ed244bf839c5ccfadb0b9352c8be7 (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
/* SPDX-License-Identifier: GPL-2.0 */

#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 notifier_block;

void add_device_randomness(const void *buf, size_t len);
void __init add_bootloader_randomness(const void *buf, size_t len);
void add_input_randomness(unsigned int type, unsigned int code,
			  unsigned int value) __latent_entropy;
void add_interrupt_randomness(int irq) __latent_entropy;
void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy);

#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

#if IS_ENABLED(CONFIG_VMGENID)
void add_vmfork_randomness(const void *unique_vm_id, size_t len);
int register_random_vmfork_notifier(struct notifier_block *nb);
int unregister_random_vmfork_notifier(struct notifier_block *nb);
#else
static inline int register_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
#endif

void get_random_bytes(void *buf, size_t len);
u8 get_random_u8(void);
u16 get_random_u16(void);
u32 get_random_u32(void);
u64 get_random_u64(void);
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)
{
	return get_random_long() & CANARY_MASK;
}

void __init random_init_early(const char *command_line);
void __init random_init(void);
bool rng_is_initialized(void);
int wait_for_random_bytes(void);

/* 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, size_t nbytes)
{
	int ret = wait_for_random_bytes();
	get_random_bytes(buf, nbytes);
	return ret;
}

#define declare_get_random_var_wait(name, ret_type) \
	static inline int get_random_ ## name ## _wait(ret_type *out) { \
		int ret = wait_for_random_bytes(); \
		if (unlikely(ret)) \
			return ret; \
		*out = get_random_ ## name(); \
		return 0; \
	}
declare_get_random_var_wait(u8, u8)
declare_get_random_var_wait(u16, u16)
declare_get_random_var_wait(u32, u32)
declare_get_random_var_wait(u64, u32)
declare_get_random_var_wait(long, unsigned long)
#undef declare_get_random_var

/*
 * 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>

#include <asm/archrandom.h>

/*
 * 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_longs_early
static inline size_t __init arch_get_random_seed_longs_early(unsigned long *v, size_t max_longs)
{
	WARN_ON(system_state != SYSTEM_BOOTING);
	return arch_get_random_seed_longs(v, max_longs);
}
#endif

#ifndef arch_get_random_longs_early
static inline bool __init arch_get_random_longs_early(unsigned long *v, size_t max_longs)
{
	WARN_ON(system_state != SYSTEM_BOOTING);
	return arch_get_random_longs(v, max_longs);
}
#endif

#ifdef CONFIG_SMP
int random_prepare_cpu(unsigned int cpu);
int random_online_cpu(unsigned int cpu);
#endif

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

#endif /* _LINUX_RANDOM_H */