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Commit | Line | Data |
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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | /* |
3 | * include/linux/random.h | |
4 | * | |
5 | * Include file for the random number generator. | |
6 | */ | |
1da177e4 LT |
7 | #ifndef _LINUX_RANDOM_H |
8 | #define _LINUX_RANDOM_H | |
9 | ||
253d3194 MR |
10 | #include <linux/bug.h> |
11 | #include <linux/kernel.h> | |
205a525c | 12 | #include <linux/list.h> |
897ece56 DB |
13 | #include <linux/once.h> |
14 | ||
607ca46e | 15 | #include <uapi/linux/random.h> |
1da177e4 | 16 | |
205a525c HX |
17 | struct random_ready_callback { |
18 | struct list_head list; | |
19 | void (*func)(struct random_ready_callback *rdy); | |
20 | struct module *owner; | |
21 | }; | |
22 | ||
a2080a67 | 23 | extern void add_device_randomness(const void *, unsigned int); |
428826f5 | 24 | extern void add_bootloader_randomness(const void *, unsigned int); |
38addce8 | 25 | |
7e756f42 | 26 | #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) |
38addce8 ER |
27 | static inline void add_latent_entropy(void) |
28 | { | |
29 | add_device_randomness((const void *)&latent_entropy, | |
30 | sizeof(latent_entropy)); | |
31 | } | |
32 | #else | |
33 | static inline void add_latent_entropy(void) {} | |
34 | #endif | |
35 | ||
1da177e4 | 36 | extern void add_input_randomness(unsigned int type, unsigned int code, |
0766f788 ER |
37 | unsigned int value) __latent_entropy; |
38 | extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy; | |
1da177e4 LT |
39 | |
40 | extern void get_random_bytes(void *buf, int nbytes); | |
e297a783 | 41 | extern int wait_for_random_bytes(void); |
d5553523 | 42 | extern int __init rand_initialize(void); |
9a47249d | 43 | extern bool rng_is_initialized(void); |
205a525c HX |
44 | extern int add_random_ready_callback(struct random_ready_callback *rdy); |
45 | extern void del_random_ready_callback(struct random_ready_callback *rdy); | |
753d433b | 46 | extern int __must_check get_random_bytes_arch(void *buf, int nbytes); |
1da177e4 | 47 | |
1da177e4 | 48 | #ifndef MODULE |
54047320 | 49 | extern const struct file_operations random_fops, urandom_fops; |
1da177e4 LT |
50 | #endif |
51 | ||
c440408c JD |
52 | u32 get_random_u32(void); |
53 | u64 get_random_u64(void); | |
54 | static inline unsigned int get_random_int(void) | |
55 | { | |
56 | return get_random_u32(); | |
57 | } | |
58 | static inline unsigned long get_random_long(void) | |
59 | { | |
60 | #if BITS_PER_LONG == 64 | |
61 | return get_random_u64(); | |
62 | #else | |
63 | return get_random_u32(); | |
64 | #endif | |
65 | } | |
66 | ||
022c2040 RR |
67 | /* |
68 | * On 64-bit architectures, protect against non-terminated C string overflows | |
69 | * by zeroing out the first byte of the canary; this leaves 56 bits of entropy. | |
70 | */ | |
71 | #ifdef CONFIG_64BIT | |
72 | # ifdef __LITTLE_ENDIAN | |
73 | # define CANARY_MASK 0xffffffffffffff00UL | |
74 | # else /* big endian, 64 bits: */ | |
75 | # define CANARY_MASK 0x00ffffffffffffffUL | |
76 | # endif | |
77 | #else /* 32 bits: */ | |
78 | # define CANARY_MASK 0xffffffffUL | |
79 | #endif | |
80 | ||
81 | static inline unsigned long get_random_canary(void) | |
82 | { | |
83 | unsigned long val = get_random_long(); | |
84 | ||
85 | return val & CANARY_MASK; | |
86 | } | |
87 | ||
da9ba564 JD |
88 | /* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes). |
89 | * Returns the result of the call to wait_for_random_bytes. */ | |
90 | static inline int get_random_bytes_wait(void *buf, int nbytes) | |
91 | { | |
92 | int ret = wait_for_random_bytes(); | |
da9ba564 | 93 | get_random_bytes(buf, nbytes); |
25e3fca4 | 94 | return ret; |
da9ba564 JD |
95 | } |
96 | ||
97 | #define declare_get_random_var_wait(var) \ | |
98 | static inline int get_random_ ## var ## _wait(var *out) { \ | |
99 | int ret = wait_for_random_bytes(); \ | |
100 | if (unlikely(ret)) \ | |
101 | return ret; \ | |
102 | *out = get_random_ ## var(); \ | |
103 | return 0; \ | |
104 | } | |
105 | declare_get_random_var_wait(u32) | |
106 | declare_get_random_var_wait(u64) | |
107 | declare_get_random_var_wait(int) | |
108 | declare_get_random_var_wait(long) | |
109 | #undef declare_get_random_var | |
110 | ||
99fdafde | 111 | unsigned long randomize_page(unsigned long start, unsigned long range); |
1da177e4 | 112 | |
496f2f93 | 113 | u32 prandom_u32(void); |
a98406e2 | 114 | void prandom_bytes(void *buf, size_t nbytes); |
496f2f93 | 115 | void prandom_seed(u32 seed); |
4af712e8 | 116 | void prandom_reseed_late(void); |
aaa248f6 | 117 | |
38e9efcd | 118 | struct rnd_state { |
a98814ce | 119 | __u32 s1, s2, s3, s4; |
38e9efcd DB |
120 | }; |
121 | ||
a98814ce | 122 | u32 prandom_u32_state(struct rnd_state *state); |
a98406e2 | 123 | void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes); |
897ece56 DB |
124 | void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state); |
125 | ||
126 | #define prandom_init_once(pcpu_state) \ | |
127 | DO_ONCE(prandom_seed_full_state, (pcpu_state)) | |
5960164f | 128 | |
f337db64 DB |
129 | /** |
130 | * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro) | |
131 | * @ep_ro: right open interval endpoint | |
132 | * | |
133 | * Returns a pseudo-random number that is in interval [0, ep_ro). Note | |
134 | * that the result depends on PRNG being well distributed in [0, ~0U] | |
135 | * u32 space. Here we use maximally equidistributed combined Tausworthe | |
136 | * generator, that is, prandom_u32(). This is useful when requesting a | |
137 | * random index of an array containing ep_ro elements, for example. | |
138 | * | |
139 | * Returns: pseudo-random number in interval [0, ep_ro) | |
140 | */ | |
141 | static inline u32 prandom_u32_max(u32 ep_ro) | |
142 | { | |
143 | return (u32)(((u64) prandom_u32() * ep_ro) >> 32); | |
144 | } | |
145 | ||
5960164f JE |
146 | /* |
147 | * Handle minimum values for seeds | |
148 | */ | |
149 | static inline u32 __seed(u32 x, u32 m) | |
150 | { | |
151 | return (x < m) ? x + m : x; | |
152 | } | |
153 | ||
154 | /** | |
496f2f93 | 155 | * prandom_seed_state - set seed for prandom_u32_state(). |
5960164f JE |
156 | * @state: pointer to state structure to receive the seed. |
157 | * @seed: arbitrary 64-bit value to use as a seed. | |
158 | */ | |
496f2f93 | 159 | static inline void prandom_seed_state(struct rnd_state *state, u64 seed) |
5960164f JE |
160 | { |
161 | u32 i = (seed >> 32) ^ (seed << 10) ^ seed; | |
162 | ||
a98814ce DB |
163 | state->s1 = __seed(i, 2U); |
164 | state->s2 = __seed(i, 8U); | |
165 | state->s3 = __seed(i, 16U); | |
166 | state->s4 = __seed(i, 128U); | |
5960164f JE |
167 | } |
168 | ||
63d77173 PA |
169 | #ifdef CONFIG_ARCH_RANDOM |
170 | # include <asm/archrandom.h> | |
171 | #else | |
904caa64 | 172 | static inline bool __must_check arch_get_random_long(unsigned long *v) |
63d77173 | 173 | { |
66f5ae89 | 174 | return false; |
63d77173 | 175 | } |
904caa64 | 176 | static inline bool __must_check arch_get_random_int(unsigned int *v) |
63d77173 | 177 | { |
66f5ae89 | 178 | return false; |
63d77173 | 179 | } |
904caa64 | 180 | static inline bool __must_check arch_get_random_seed_long(unsigned long *v) |
d20f78d2 | 181 | { |
66f5ae89 | 182 | return false; |
d20f78d2 | 183 | } |
904caa64 | 184 | static inline bool __must_check arch_get_random_seed_int(unsigned int *v) |
d20f78d2 | 185 | { |
66f5ae89 | 186 | return false; |
d20f78d2 | 187 | } |
63d77173 PA |
188 | #endif |
189 | ||
253d3194 MR |
190 | /* |
191 | * Called from the boot CPU during startup; not valid to call once | |
192 | * secondary CPUs are up and preemption is possible. | |
193 | */ | |
194 | #ifndef arch_get_random_seed_long_early | |
195 | static inline bool __init arch_get_random_seed_long_early(unsigned long *v) | |
196 | { | |
197 | WARN_ON(system_state != SYSTEM_BOOTING); | |
198 | return arch_get_random_seed_long(v); | |
199 | } | |
200 | #endif | |
201 | ||
202 | #ifndef arch_get_random_long_early | |
203 | static inline bool __init arch_get_random_long_early(unsigned long *v) | |
204 | { | |
205 | WARN_ON(system_state != SYSTEM_BOOTING); | |
206 | return arch_get_random_long(v); | |
207 | } | |
208 | #endif | |
209 | ||
055dc21a TH |
210 | /* Pseudo random number generator from numerical recipes. */ |
211 | static inline u32 next_pseudo_random32(u32 seed) | |
212 | { | |
213 | return seed * 1664525 + 1013904223; | |
214 | } | |
215 | ||
1da177e4 | 216 | #endif /* _LINUX_RANDOM_H */ |