1 /* SPDX-License-Identifier: GPL-2.0 */
2
3 #ifndef _LINUX_RANDOM_H
4 #define _LINUX_RANDOM_H
5
6 #include <linux/bug.h>
7 #include <linux/kernel.h>
8 #include <linux/list.h>
9 #include <linux/once.h>
10
11 #include <uapi/linux/random.h>
12
13 struct notifier_block;
14
15 void add_device_randomness(const void *buf, size_t len);
16 void __init add_bootloader_randomness(const void *buf, size_t len);
17 void add_input_randomness(unsigned int type, unsigned int code,
18 unsigned int value) __latent_entropy;
19 void add_interrupt_randomness(int irq) __latent_entropy;
20 void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy);
21
add_latent_entropy(void)22 static inline void add_latent_entropy(void)
23 {
24 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
25 add_device_randomness((const void *)&latent_entropy, sizeof(latent_entropy));
26 #else
27 add_device_randomness(NULL, 0);
28 #endif
29 }
30
31 void get_random_bytes(void *buf, size_t len);
32 size_t __must_check get_random_bytes_arch(void *buf, size_t len);
33 u32 get_random_u32(void);
34 u64 get_random_u64(void);
get_random_int(void)35 static inline unsigned int get_random_int(void)
36 {
37 return get_random_u32();
38 }
get_random_long(void)39 static inline unsigned long get_random_long(void)
40 {
41 #if BITS_PER_LONG == 64
42 return get_random_u64();
43 #else
44 return get_random_u32();
45 #endif
46 }
47
48 /*
49 * On 64-bit architectures, protect against non-terminated C string overflows
50 * by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
51 */
52 #ifdef CONFIG_64BIT
53 # ifdef __LITTLE_ENDIAN
54 # define CANARY_MASK 0xffffffffffffff00UL
55 # else /* big endian, 64 bits: */
56 # define CANARY_MASK 0x00ffffffffffffffUL
57 # endif
58 #else /* 32 bits: */
59 # define CANARY_MASK 0xffffffffUL
60 #endif
61
get_random_canary(void)62 static inline unsigned long get_random_canary(void)
63 {
64 return get_random_long() & CANARY_MASK;
65 }
66
67 int __init random_init(const char *command_line);
68 bool rng_is_initialized(void);
69 int wait_for_random_bytes(void);
70 int register_random_ready_notifier(struct notifier_block *nb);
71 int unregister_random_ready_notifier(struct notifier_block *nb);
72
73 /* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
74 * Returns the result of the call to wait_for_random_bytes. */
get_random_bytes_wait(void * buf,size_t nbytes)75 static inline int get_random_bytes_wait(void *buf, size_t nbytes)
76 {
77 int ret = wait_for_random_bytes();
78 get_random_bytes(buf, nbytes);
79 return ret;
80 }
81
82 #define declare_get_random_var_wait(name, ret_type) \
83 static inline int get_random_ ## name ## _wait(ret_type *out) { \
84 int ret = wait_for_random_bytes(); \
85 if (unlikely(ret)) \
86 return ret; \
87 *out = get_random_ ## name(); \
88 return 0; \
89 }
declare_get_random_var_wait(u32,u32)90 declare_get_random_var_wait(u32, u32)
91 declare_get_random_var_wait(u64, u32)
92 declare_get_random_var_wait(int, unsigned int)
93 declare_get_random_var_wait(long, unsigned long)
94 #undef declare_get_random_var
95
96 /*
97 * This is designed to be standalone for just prandom
98 * users, but for now we include it from <linux/random.h>
99 * for legacy reasons.
100 */
101 #include <linux/prandom.h>
102
103 #ifdef CONFIG_ARCH_RANDOM
104 # include <asm/archrandom.h>
105 #else
106 static inline bool __must_check arch_get_random_long(unsigned long *v) { return false; }
107 static inline bool __must_check arch_get_random_int(unsigned int *v) { return false; }
108 static inline bool __must_check arch_get_random_seed_long(unsigned long *v) { return false; }
109 static inline bool __must_check arch_get_random_seed_int(unsigned int *v) { return false; }
110 #endif
111
112 /*
113 * Called from the boot CPU during startup; not valid to call once
114 * secondary CPUs are up and preemption is possible.
115 */
116 #ifndef arch_get_random_seed_long_early
117 static inline bool __init arch_get_random_seed_long_early(unsigned long *v)
118 {
119 WARN_ON(system_state != SYSTEM_BOOTING);
120 return arch_get_random_seed_long(v);
121 }
122 #endif
123
124 #ifndef arch_get_random_long_early
arch_get_random_long_early(unsigned long * v)125 static inline bool __init arch_get_random_long_early(unsigned long *v)
126 {
127 WARN_ON(system_state != SYSTEM_BOOTING);
128 return arch_get_random_long(v);
129 }
130 #endif
131
132 #ifdef CONFIG_SMP
133 int random_prepare_cpu(unsigned int cpu);
134 int random_online_cpu(unsigned int cpu);
135 #endif
136
137 #ifndef MODULE
138 extern const struct file_operations random_fops, urandom_fops;
139 #endif
140
141 #endif /* _LINUX_RANDOM_H */
142