random.h (4319B)
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 13struct notifier_block; 14 15void add_device_randomness(const void *buf, size_t len); 16void __init add_bootloader_randomness(const void *buf, size_t len); 17void add_input_randomness(unsigned int type, unsigned int code, 18 unsigned int value) __latent_entropy; 19void add_interrupt_randomness(int irq) __latent_entropy; 20void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy); 21 22#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) 23static inline void add_latent_entropy(void) 24{ 25 add_device_randomness((const void *)&latent_entropy, sizeof(latent_entropy)); 26} 27#else 28static inline void add_latent_entropy(void) { } 29#endif 30 31#if IS_ENABLED(CONFIG_VMGENID) 32void add_vmfork_randomness(const void *unique_vm_id, size_t len); 33int register_random_vmfork_notifier(struct notifier_block *nb); 34int unregister_random_vmfork_notifier(struct notifier_block *nb); 35#else 36static inline int register_random_vmfork_notifier(struct notifier_block *nb) { return 0; } 37static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) { return 0; } 38#endif 39 40void get_random_bytes(void *buf, size_t len); 41u32 get_random_u32(void); 42u64 get_random_u64(void); 43static inline unsigned int get_random_int(void) 44{ 45 return get_random_u32(); 46} 47static inline unsigned long get_random_long(void) 48{ 49#if BITS_PER_LONG == 64 50 return get_random_u64(); 51#else 52 return get_random_u32(); 53#endif 54} 55 56/* 57 * On 64-bit architectures, protect against non-terminated C string overflows 58 * by zeroing out the first byte of the canary; this leaves 56 bits of entropy. 59 */ 60#ifdef CONFIG_64BIT 61# ifdef __LITTLE_ENDIAN 62# define CANARY_MASK 0xffffffffffffff00UL 63# else /* big endian, 64 bits: */ 64# define CANARY_MASK 0x00ffffffffffffffUL 65# endif 66#else /* 32 bits: */ 67# define CANARY_MASK 0xffffffffUL 68#endif 69 70static inline unsigned long get_random_canary(void) 71{ 72 return get_random_long() & CANARY_MASK; 73} 74 75int __init random_init(const char *command_line); 76bool rng_is_initialized(void); 77int wait_for_random_bytes(void); 78 79/* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes). 80 * Returns the result of the call to wait_for_random_bytes. */ 81static inline int get_random_bytes_wait(void *buf, size_t nbytes) 82{ 83 int ret = wait_for_random_bytes(); 84 get_random_bytes(buf, nbytes); 85 return ret; 86} 87 88#define declare_get_random_var_wait(name, ret_type) \ 89 static inline int get_random_ ## name ## _wait(ret_type *out) { \ 90 int ret = wait_for_random_bytes(); \ 91 if (unlikely(ret)) \ 92 return ret; \ 93 *out = get_random_ ## name(); \ 94 return 0; \ 95 } 96declare_get_random_var_wait(u32, u32) 97declare_get_random_var_wait(u64, u32) 98declare_get_random_var_wait(int, unsigned int) 99declare_get_random_var_wait(long, unsigned long) 100#undef declare_get_random_var 101 102/* 103 * This is designed to be standalone for just prandom 104 * users, but for now we include it from <linux/random.h> 105 * for legacy reasons. 106 */ 107#include <linux/prandom.h> 108 109#ifdef CONFIG_ARCH_RANDOM 110# include <asm/archrandom.h> 111#else 112static inline bool __must_check arch_get_random_long(unsigned long *v) { return false; } 113static inline bool __must_check arch_get_random_int(unsigned int *v) { return false; } 114static inline bool __must_check arch_get_random_seed_long(unsigned long *v) { return false; } 115static inline bool __must_check arch_get_random_seed_int(unsigned int *v) { return false; } 116#endif 117 118/* 119 * Called from the boot CPU during startup; not valid to call once 120 * secondary CPUs are up and preemption is possible. 121 */ 122#ifndef arch_get_random_seed_long_early 123static inline bool __init arch_get_random_seed_long_early(unsigned long *v) 124{ 125 WARN_ON(system_state != SYSTEM_BOOTING); 126 return arch_get_random_seed_long(v); 127} 128#endif 129 130#ifndef arch_get_random_long_early 131static inline bool __init arch_get_random_long_early(unsigned long *v) 132{ 133 WARN_ON(system_state != SYSTEM_BOOTING); 134 return arch_get_random_long(v); 135} 136#endif 137 138#ifdef CONFIG_SMP 139int random_prepare_cpu(unsigned int cpu); 140int random_online_cpu(unsigned int cpu); 141#endif 142 143#ifndef MODULE 144extern const struct file_operations random_fops, urandom_fops; 145#endif 146 147#endif /* _LINUX_RANDOM_H */