203 lines
5.2 KiB
C
203 lines
5.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* include/linux/random.h
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*
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* Include file for the random number generator.
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*/
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#ifndef _LINUX_RANDOM_H
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#define _LINUX_RANDOM_H
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#include <linux/list.h>
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#include <linux/once.h>
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#include <uapi/linux/random.h>
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struct random_ready_callback {
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struct list_head list;
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void (*func)(struct random_ready_callback *rdy);
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struct module *owner;
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};
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extern void add_device_randomness(const void *, unsigned int);
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extern void add_bootloader_randomness(const void *, unsigned int);
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#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
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static inline void add_latent_entropy(void)
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{
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add_device_randomness((const void *)&latent_entropy,
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sizeof(latent_entropy));
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}
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#else
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static inline void add_latent_entropy(void) {}
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#endif
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extern void add_input_randomness(unsigned int type, unsigned int code,
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unsigned int value) __latent_entropy;
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extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
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extern void get_random_bytes(void *buf, int nbytes);
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extern int wait_for_random_bytes(void);
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extern int __init rand_initialize(void);
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extern bool rng_is_initialized(void);
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extern int add_random_ready_callback(struct random_ready_callback *rdy);
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extern void del_random_ready_callback(struct random_ready_callback *rdy);
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extern int __must_check get_random_bytes_arch(void *buf, int nbytes);
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#ifndef MODULE
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extern const struct file_operations random_fops, urandom_fops;
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#endif
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u32 get_random_u32(void);
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u64 get_random_u64(void);
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static inline unsigned int get_random_int(void)
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{
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return get_random_u32();
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}
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static inline unsigned long get_random_long(void)
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{
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#if BITS_PER_LONG == 64
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return get_random_u64();
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#else
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return get_random_u32();
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#endif
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}
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/*
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* On 64-bit architectures, protect against non-terminated C string overflows
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* by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
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*/
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#ifdef CONFIG_64BIT
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# ifdef __LITTLE_ENDIAN
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# define CANARY_MASK 0xffffffffffffff00UL
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# else /* big endian, 64 bits: */
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# define CANARY_MASK 0x00ffffffffffffffUL
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# endif
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#else /* 32 bits: */
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# define CANARY_MASK 0xffffffffUL
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#endif
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static inline unsigned long get_random_canary(void)
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{
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unsigned long val = get_random_long();
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return val & CANARY_MASK;
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}
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/* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
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* Returns the result of the call to wait_for_random_bytes. */
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static inline int get_random_bytes_wait(void *buf, int nbytes)
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{
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int ret = wait_for_random_bytes();
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get_random_bytes(buf, nbytes);
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return ret;
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}
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#define declare_get_random_var_wait(var) \
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static inline int get_random_ ## var ## _wait(var *out) { \
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int ret = wait_for_random_bytes(); \
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if (unlikely(ret)) \
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return ret; \
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*out = get_random_ ## var(); \
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return 0; \
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}
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declare_get_random_var_wait(u32)
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declare_get_random_var_wait(u64)
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declare_get_random_var_wait(int)
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declare_get_random_var_wait(long)
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#undef declare_get_random_var
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unsigned long randomize_page(unsigned long start, unsigned long range);
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u32 prandom_u32(void);
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void prandom_bytes(void *buf, size_t nbytes);
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void prandom_seed(u32 seed);
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void prandom_reseed_late(void);
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struct rnd_state {
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__u32 s1, s2, s3, s4;
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};
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u32 prandom_u32_state(struct rnd_state *state);
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void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
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void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
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#define prandom_init_once(pcpu_state) \
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DO_ONCE(prandom_seed_full_state, (pcpu_state))
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/**
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* prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
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* @ep_ro: right open interval endpoint
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*
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* Returns a pseudo-random number that is in interval [0, ep_ro). Note
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* that the result depends on PRNG being well distributed in [0, ~0U]
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* u32 space. Here we use maximally equidistributed combined Tausworthe
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* generator, that is, prandom_u32(). This is useful when requesting a
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* random index of an array containing ep_ro elements, for example.
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*
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* Returns: pseudo-random number in interval [0, ep_ro)
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*/
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static inline u32 prandom_u32_max(u32 ep_ro)
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{
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return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
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}
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/*
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* Handle minimum values for seeds
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*/
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static inline u32 __seed(u32 x, u32 m)
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{
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return (x < m) ? x + m : x;
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}
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/**
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* prandom_seed_state - set seed for prandom_u32_state().
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* @state: pointer to state structure to receive the seed.
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* @seed: arbitrary 64-bit value to use as a seed.
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*/
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static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
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{
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u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
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state->s1 = __seed(i, 2U);
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state->s2 = __seed(i, 8U);
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state->s3 = __seed(i, 16U);
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state->s4 = __seed(i, 128U);
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}
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#ifdef CONFIG_ARCH_RANDOM
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# include <asm/archrandom.h>
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#else
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static inline bool arch_get_random_long(unsigned long *v)
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{
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return 0;
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}
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static inline bool arch_get_random_int(unsigned int *v)
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{
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return 0;
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}
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static inline bool arch_has_random(void)
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{
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return 0;
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}
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static inline bool arch_get_random_seed_long(unsigned long *v)
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{
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return 0;
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}
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static inline bool arch_get_random_seed_int(unsigned int *v)
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{
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return 0;
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}
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static inline bool arch_has_random_seed(void)
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{
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return 0;
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}
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#endif
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/* Pseudo random number generator from numerical recipes. */
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static inline u32 next_pseudo_random32(u32 seed)
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{
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return seed * 1664525 + 1013904223;
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}
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#endif /* _LINUX_RANDOM_H */
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