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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 | ||
205a525c | 10 | #include <linux/list.h> |
897ece56 DB |
11 | #include <linux/once.h> |
12 | ||
607ca46e | 13 | #include <uapi/linux/random.h> |
1da177e4 | 14 | |
205a525c HX |
15 | struct random_ready_callback { |
16 | struct list_head list; | |
17 | void (*func)(struct random_ready_callback *rdy); | |
18 | struct module *owner; | |
19 | }; | |
20 | ||
a2080a67 | 21 | extern void add_device_randomness(const void *, unsigned int); |
38addce8 ER |
22 | |
23 | #if defined(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) && !defined(__CHECKER__) | |
24 | static inline void add_latent_entropy(void) | |
25 | { | |
26 | add_device_randomness((const void *)&latent_entropy, | |
27 | sizeof(latent_entropy)); | |
28 | } | |
29 | #else | |
30 | static inline void add_latent_entropy(void) {} | |
31 | #endif | |
32 | ||
1da177e4 | 33 | extern void add_input_randomness(unsigned int type, unsigned int code, |
0766f788 ER |
34 | unsigned int value) __latent_entropy; |
35 | extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy; | |
1da177e4 LT |
36 | |
37 | extern void get_random_bytes(void *buf, int nbytes); | |
e297a783 | 38 | extern int wait_for_random_bytes(void); |
9a47249d | 39 | extern bool rng_is_initialized(void); |
205a525c HX |
40 | extern int add_random_ready_callback(struct random_ready_callback *rdy); |
41 | extern void del_random_ready_callback(struct random_ready_callback *rdy); | |
753d433b | 42 | extern int __must_check get_random_bytes_arch(void *buf, int nbytes); |
1da177e4 | 43 | |
1da177e4 | 44 | #ifndef MODULE |
54047320 | 45 | extern const struct file_operations random_fops, urandom_fops; |
1da177e4 LT |
46 | #endif |
47 | ||
c440408c JD |
48 | u32 get_random_u32(void); |
49 | u64 get_random_u64(void); | |
50 | static inline unsigned int get_random_int(void) | |
51 | { | |
52 | return get_random_u32(); | |
53 | } | |
54 | static inline unsigned long get_random_long(void) | |
55 | { | |
56 | #if BITS_PER_LONG == 64 | |
57 | return get_random_u64(); | |
58 | #else | |
59 | return get_random_u32(); | |
60 | #endif | |
61 | } | |
62 | ||
022c2040 RR |
63 | /* |
64 | * On 64-bit architectures, protect against non-terminated C string overflows | |
65 | * by zeroing out the first byte of the canary; this leaves 56 bits of entropy. | |
66 | */ | |
67 | #ifdef CONFIG_64BIT | |
68 | # ifdef __LITTLE_ENDIAN | |
69 | # define CANARY_MASK 0xffffffffffffff00UL | |
70 | # else /* big endian, 64 bits: */ | |
71 | # define CANARY_MASK 0x00ffffffffffffffUL | |
72 | # endif | |
73 | #else /* 32 bits: */ | |
74 | # define CANARY_MASK 0xffffffffUL | |
75 | #endif | |
76 | ||
77 | static inline unsigned long get_random_canary(void) | |
78 | { | |
79 | unsigned long val = get_random_long(); | |
80 | ||
81 | return val & CANARY_MASK; | |
82 | } | |
83 | ||
da9ba564 JD |
84 | /* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes). |
85 | * Returns the result of the call to wait_for_random_bytes. */ | |
86 | static inline int get_random_bytes_wait(void *buf, int nbytes) | |
87 | { | |
88 | int ret = wait_for_random_bytes(); | |
da9ba564 | 89 | get_random_bytes(buf, nbytes); |
25e3fca4 | 90 | return ret; |
da9ba564 JD |
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 | } | |
101 | declare_get_random_var_wait(u32) | |
102 | declare_get_random_var_wait(u64) | |
103 | declare_get_random_var_wait(int) | |
104 | declare_get_random_var_wait(long) | |
105 | #undef declare_get_random_var | |
106 | ||
99fdafde | 107 | unsigned long randomize_page(unsigned long start, unsigned long range); |
1da177e4 | 108 | |
496f2f93 | 109 | u32 prandom_u32(void); |
a98406e2 | 110 | void prandom_bytes(void *buf, size_t nbytes); |
496f2f93 | 111 | void prandom_seed(u32 seed); |
4af712e8 | 112 | void prandom_reseed_late(void); |
aaa248f6 | 113 | |
38e9efcd | 114 | struct rnd_state { |
a98814ce | 115 | __u32 s1, s2, s3, s4; |
38e9efcd DB |
116 | }; |
117 | ||
a98814ce | 118 | u32 prandom_u32_state(struct rnd_state *state); |
a98406e2 | 119 | void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes); |
897ece56 DB |
120 | void 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)) | |
5960164f | 124 | |
f337db64 DB |
125 | /** |
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 | */ | |
137 | static inline u32 prandom_u32_max(u32 ep_ro) | |
138 | { | |
139 | return (u32)(((u64) prandom_u32() * ep_ro) >> 32); | |
140 | } | |
141 | ||
5960164f JE |
142 | /* |
143 | * Handle minimum values for seeds | |
144 | */ | |
145 | static inline u32 __seed(u32 x, u32 m) | |
146 | { | |
147 | return (x < m) ? x + m : x; | |
148 | } | |
149 | ||
150 | /** | |
496f2f93 | 151 | * prandom_seed_state - set seed for prandom_u32_state(). |
5960164f JE |
152 | * @state: pointer to state structure to receive the seed. |
153 | * @seed: arbitrary 64-bit value to use as a seed. | |
154 | */ | |
496f2f93 | 155 | static inline void prandom_seed_state(struct rnd_state *state, u64 seed) |
5960164f JE |
156 | { |
157 | u32 i = (seed >> 32) ^ (seed << 10) ^ seed; | |
158 | ||
a98814ce DB |
159 | state->s1 = __seed(i, 2U); |
160 | state->s2 = __seed(i, 8U); | |
161 | state->s3 = __seed(i, 16U); | |
162 | state->s4 = __seed(i, 128U); | |
5960164f JE |
163 | } |
164 | ||
63d77173 PA |
165 | #ifdef CONFIG_ARCH_RANDOM |
166 | # include <asm/archrandom.h> | |
167 | #else | |
117780ee | 168 | static inline bool arch_get_random_long(unsigned long *v) |
63d77173 PA |
169 | { |
170 | return 0; | |
171 | } | |
117780ee | 172 | static inline bool arch_get_random_int(unsigned int *v) |
63d77173 PA |
173 | { |
174 | return 0; | |
175 | } | |
117780ee | 176 | static inline bool arch_has_random(void) |
7b878d4b PA |
177 | { |
178 | return 0; | |
179 | } | |
117780ee | 180 | static inline bool arch_get_random_seed_long(unsigned long *v) |
d20f78d2 PA |
181 | { |
182 | return 0; | |
183 | } | |
117780ee | 184 | static inline bool arch_get_random_seed_int(unsigned int *v) |
d20f78d2 PA |
185 | { |
186 | return 0; | |
187 | } | |
117780ee | 188 | static inline bool arch_has_random_seed(void) |
7b878d4b PA |
189 | { |
190 | return 0; | |
191 | } | |
63d77173 PA |
192 | #endif |
193 | ||
055dc21a TH |
194 | /* Pseudo random number generator from numerical recipes. */ |
195 | static inline u32 next_pseudo_random32(u32 seed) | |
196 | { | |
197 | return seed * 1664525 + 1013904223; | |
198 | } | |
199 | ||
1da177e4 | 200 | #endif /* _LINUX_RANDOM_H */ |