1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * include/linux/random.h
4 *
5 * Include file for the random number generator.
6 */
7 #ifndef _LINUX_RANDOM_H
8 #define _LINUX_RANDOM_H
9
10 #include <linux/bug.h>
11 #include <linux/kernel.h>
12 #include <linux/list.h>
13 #include <linux/once.h>
14
15 #include <uapi/linux/random.h>
16
17 struct random_ready_callback {
18 struct list_head list;
19 void (*func)(struct random_ready_callback *rdy);
20 struct module *owner;
21 };
22
23 extern void add_device_randomness(const void *, unsigned int);
24 extern void add_bootloader_randomness(const void *, unsigned int);
25
26 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
add_latent_entropy(void)27 static inline void add_latent_entropy(void)
28 {
29 add_device_randomness((const void *)&latent_entropy,
30 sizeof(latent_entropy));
31 }
32 #else
add_latent_entropy(void)33 static inline void add_latent_entropy(void) {}
34 #endif
35
36 extern void add_input_randomness(unsigned int type, unsigned int code,
37 unsigned int value) __latent_entropy;
38 extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
39
40 extern void get_random_bytes(void *buf, int nbytes);
41 extern int wait_for_random_bytes(void);
42 extern int __init rand_initialize(void);
43 extern bool rng_is_initialized(void);
44 extern int add_random_ready_callback(struct random_ready_callback *rdy);
45 extern void del_random_ready_callback(struct random_ready_callback *rdy);
46 extern int __must_check get_random_bytes_arch(void *buf, int nbytes);
47
48 #ifndef MODULE
49 extern const struct file_operations random_fops, urandom_fops;
50 #endif
51
52 u32 get_random_u32(void);
53 u64 get_random_u64(void);
get_random_int(void)54 static inline unsigned int get_random_int(void)
55 {
56 return get_random_u32();
57 }
get_random_long(void)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
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
get_random_canary(void)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
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. */
get_random_bytes_wait(void * buf,int nbytes)90 static inline int get_random_bytes_wait(void *buf, int nbytes)
91 {
92 int ret = wait_for_random_bytes();
93 get_random_bytes(buf, nbytes);
94 return ret;
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
111 unsigned long randomize_page(unsigned long start, unsigned long range);
112
113 /*
114 * This is designed to be standalone for just prandom
115 * users, but for now we include it from <linux/random.h>
116 * for legacy reasons.
117 */
118 #include <linux/prandom.h>
119
120 #ifdef CONFIG_ARCH_RANDOM
121 # include <asm/archrandom.h>
122 #else
arch_get_random_long(unsigned long * v)123 static inline bool __must_check arch_get_random_long(unsigned long *v)
124 {
125 return false;
126 }
arch_get_random_int(unsigned int * v)127 static inline bool __must_check arch_get_random_int(unsigned int *v)
128 {
129 return false;
130 }
arch_get_random_seed_long(unsigned long * v)131 static inline bool __must_check arch_get_random_seed_long(unsigned long *v)
132 {
133 return false;
134 }
arch_get_random_seed_int(unsigned int * v)135 static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
136 {
137 return false;
138 }
139 #endif
140
141 /*
142 * Called from the boot CPU during startup; not valid to call once
143 * secondary CPUs are up and preemption is possible.
144 */
145 #ifndef arch_get_random_seed_long_early
arch_get_random_seed_long_early(unsigned long * v)146 static inline bool __init arch_get_random_seed_long_early(unsigned long *v)
147 {
148 WARN_ON(system_state != SYSTEM_BOOTING);
149 return arch_get_random_seed_long(v);
150 }
151 #endif
152
153 #ifndef arch_get_random_long_early
arch_get_random_long_early(unsigned long * v)154 static inline bool __init arch_get_random_long_early(unsigned long *v)
155 {
156 WARN_ON(system_state != SYSTEM_BOOTING);
157 return arch_get_random_long(v);
158 }
159 #endif
160
161 #endif /* _LINUX_RANDOM_H */
162