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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * include/linux/random.h
3 *
4 * Include file for the random number generator.
5 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07006#ifndef _LINUX_RANDOM_H
7#define _LINUX_RANDOM_H
8
Herbert Xu205a5252015-06-09 18:19:39 +08009#include <linux/list.h>
Daniel Borkmann897ece52015-10-08 01:20:38 +020010#include <linux/once.h>
11
David Howells607ca462012-10-13 10:46:48 +010012#include <uapi/linux/random.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013
Herbert Xu205a5252015-06-09 18:19:39 +080014struct random_ready_callback {
15 struct list_head list;
16 void (*func)(struct random_ready_callback *rdy);
17 struct module *owner;
18};
19
Linus Torvaldsa2080a62012-07-04 11:16:01 -040020extern void add_device_randomness(const void *, unsigned int);
Emese Revfy38addce2016-06-20 20:41:19 +020021
22#if defined(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) && !defined(__CHECKER__)
23static inline void add_latent_entropy(void)
24{
25 add_device_randomness((const void *)&latent_entropy,
26 sizeof(latent_entropy));
27}
28#else
29static inline void add_latent_entropy(void) {}
30#endif
31
Linus Torvalds1da177e2005-04-16 15:20:36 -070032extern void add_input_randomness(unsigned int type, unsigned int code,
Emese Revfy0766f782016-06-20 20:42:34 +020033 unsigned int value) __latent_entropy;
34extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
36extern void get_random_bytes(void *buf, int nbytes);
Jason A. Donenfelde297a782017-06-07 19:58:56 -040037extern int wait_for_random_bytes(void);
Herbert Xu205a5252015-06-09 18:19:39 +080038extern int add_random_ready_callback(struct random_ready_callback *rdy);
39extern void del_random_ready_callback(struct random_ready_callback *rdy);
Theodore Ts'oc2557a32012-07-05 10:35:23 -040040extern void get_random_bytes_arch(void *buf, int nbytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#ifndef MODULE
Arjan van de Ven54047322007-02-12 00:55:28 -080043extern const struct file_operations random_fops, urandom_fops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070044#endif
45
Jason A. Donenfeldc4404082017-01-22 16:34:08 +010046u32 get_random_u32(void);
47u64 get_random_u64(void);
48static inline unsigned int get_random_int(void)
49{
50 return get_random_u32();
51}
52static inline unsigned long get_random_long(void)
53{
54#if BITS_PER_LONG == 64
55 return get_random_u64();
56#else
57 return get_random_u32();
58#endif
59}
60
Rik van Riel022c2042017-07-12 14:36:17 -070061/*
62 * On 64-bit architectures, protect against non-terminated C string overflows
63 * by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
64 */
65#ifdef CONFIG_64BIT
66# ifdef __LITTLE_ENDIAN
67# define CANARY_MASK 0xffffffffffffff00UL
68# else /* big endian, 64 bits: */
69# define CANARY_MASK 0x00ffffffffffffffUL
70# endif
71#else /* 32 bits: */
72# define CANARY_MASK 0xffffffffUL
73#endif
74
75static inline unsigned long get_random_canary(void)
76{
77 unsigned long val = get_random_long();
78
79 return val & CANARY_MASK;
80}
81
Jason A. Donenfeldda9ba562017-06-07 20:05:02 -040082/* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
83 * Returns the result of the call to wait_for_random_bytes. */
84static inline int get_random_bytes_wait(void *buf, int nbytes)
85{
86 int ret = wait_for_random_bytes();
87 if (unlikely(ret))
88 return ret;
89 get_random_bytes(buf, nbytes);
90 return 0;
91}
92
93#define declare_get_random_var_wait(var) \
94 static inline int get_random_ ## var ## _wait(var *out) { \
95 int ret = wait_for_random_bytes(); \
96 if (unlikely(ret)) \
97 return ret; \
98 *out = get_random_ ## var(); \
99 return 0; \
100 }
101declare_get_random_var_wait(u32)
102declare_get_random_var_wait(u64)
103declare_get_random_var_wait(int)
104declare_get_random_var_wait(long)
105#undef declare_get_random_var
106
Jason Cooper99fdafd2016-10-11 13:53:52 -0700107unsigned long randomize_page(unsigned long start, unsigned long range);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
Akinobu Mita496f2f92012-12-17 16:04:23 -0800109u32 prandom_u32(void);
Daniel Borkmanna98406e2014-08-23 17:03:28 +0200110void prandom_bytes(void *buf, size_t nbytes);
Akinobu Mita496f2f92012-12-17 16:04:23 -0800111void prandom_seed(u32 seed);
Hannes Frederic Sowa4af712e2013-11-11 12:20:34 +0100112void prandom_reseed_late(void);
Stephen Hemmingeraaa248f2006-10-17 00:09:42 -0700113
Daniel Borkmann38e9efc2013-11-11 12:20:35 +0100114struct rnd_state {
Daniel Borkmanna98814c2013-11-11 12:20:36 +0100115 __u32 s1, s2, s3, s4;
Daniel Borkmann38e9efc2013-11-11 12:20:35 +0100116};
117
Daniel Borkmanna98814c2013-11-11 12:20:36 +0100118u32 prandom_u32_state(struct rnd_state *state);
Daniel Borkmanna98406e2014-08-23 17:03:28 +0200119void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
Daniel Borkmann897ece52015-10-08 01:20:38 +0200120void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
121
122#define prandom_init_once(pcpu_state) \
123 DO_ONCE(prandom_seed_full_state, (pcpu_state))
Joe Eykholt59601642010-05-26 14:44:13 -0700124
Daniel Borkmannf337db62014-01-22 02:29:39 +0100125/**
126 * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
127 * @ep_ro: right open interval endpoint
128 *
129 * Returns a pseudo-random number that is in interval [0, ep_ro). Note
130 * that the result depends on PRNG being well distributed in [0, ~0U]
131 * u32 space. Here we use maximally equidistributed combined Tausworthe
132 * generator, that is, prandom_u32(). This is useful when requesting a
133 * random index of an array containing ep_ro elements, for example.
134 *
135 * Returns: pseudo-random number in interval [0, ep_ro)
136 */
137static inline u32 prandom_u32_max(u32 ep_ro)
138{
139 return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
140}
141
Joe Eykholt59601642010-05-26 14:44:13 -0700142/*
143 * Handle minimum values for seeds
144 */
145static inline u32 __seed(u32 x, u32 m)
146{
147 return (x < m) ? x + m : x;
148}
149
150/**
Akinobu Mita496f2f92012-12-17 16:04:23 -0800151 * prandom_seed_state - set seed for prandom_u32_state().
Joe Eykholt59601642010-05-26 14:44:13 -0700152 * @state: pointer to state structure to receive the seed.
153 * @seed: arbitrary 64-bit value to use as a seed.
154 */
Akinobu Mita496f2f92012-12-17 16:04:23 -0800155static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
Joe Eykholt59601642010-05-26 14:44:13 -0700156{
157 u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
158
Daniel Borkmanna98814c2013-11-11 12:20:36 +0100159 state->s1 = __seed(i, 2U);
160 state->s2 = __seed(i, 8U);
161 state->s3 = __seed(i, 16U);
162 state->s4 = __seed(i, 128U);
Joe Eykholt59601642010-05-26 14:44:13 -0700163}
164
H. Peter Anvin63d77172011-07-31 13:54:50 -0700165#ifdef CONFIG_ARCH_RANDOM
166# include <asm/archrandom.h>
167#else
H. Peter Anvin117780e2016-06-08 12:38:38 -0700168static inline bool arch_get_random_long(unsigned long *v)
H. Peter Anvin63d77172011-07-31 13:54:50 -0700169{
170 return 0;
171}
H. Peter Anvin117780e2016-06-08 12:38:38 -0700172static inline bool arch_get_random_int(unsigned int *v)
H. Peter Anvin63d77172011-07-31 13:54:50 -0700173{
174 return 0;
175}
H. Peter Anvin117780e2016-06-08 12:38:38 -0700176static inline bool arch_has_random(void)
H. Peter Anvin7b878d42014-03-17 16:36:30 -0700177{
178 return 0;
179}
H. Peter Anvin117780e2016-06-08 12:38:38 -0700180static inline bool arch_get_random_seed_long(unsigned long *v)
H. Peter Anvind20f78d2014-03-17 16:36:27 -0700181{
182 return 0;
183}
H. Peter Anvin117780e2016-06-08 12:38:38 -0700184static inline bool arch_get_random_seed_int(unsigned int *v)
H. Peter Anvind20f78d2014-03-17 16:36:27 -0700185{
186 return 0;
187}
H. Peter Anvin117780e2016-06-08 12:38:38 -0700188static inline bool arch_has_random_seed(void)
H. Peter Anvin7b878d42014-03-17 16:36:30 -0700189{
190 return 0;
191}
H. Peter Anvin63d77172011-07-31 13:54:50 -0700192#endif
193
Tom Herbert055dc212013-01-22 09:49:50 +0000194/* Pseudo random number generator from numerical recipes. */
195static inline u32 next_pseudo_random32(u32 seed)
196{
197 return seed * 1664525 + 1013904223;
198}
199
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200#endif /* _LINUX_RANDOM_H */