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__) 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 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); 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 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 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(); 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 123 static inline bool __must_check arch_get_random_long(unsigned long *v) 124 { 125 return false; 126 } 127 static inline bool __must_check arch_get_random_int(unsigned int *v) 128 { 129 return false; 130 } 131 static inline bool __must_check arch_get_random_seed_long(unsigned long *v) 132 { 133 return false; 134 } 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 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 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