mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
synced 2025-01-15 10:47:47 +00:00
205a525c33
The get_blocking_random_bytes API is broken because the wait can be arbitrarily long (potentially forever) so there is no safe way of calling it from within the kernel. This patch replaces it with a callback API instead. The callback is invoked potentially from interrupt context so the user needs to schedule their own work thread if necessary. In addition to adding callbacks, they can also be removed as otherwise this opens up a way for user-space to allocate kernel memory with no bound (by opening algif_rng descriptors and then closing them). Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
126 lines
3.2 KiB
C
126 lines
3.2 KiB
C
/*
|
|
* include/linux/random.h
|
|
*
|
|
* Include file for the random number generator.
|
|
*/
|
|
#ifndef _LINUX_RANDOM_H
|
|
#define _LINUX_RANDOM_H
|
|
|
|
#include <linux/list.h>
|
|
#include <uapi/linux/random.h>
|
|
|
|
struct random_ready_callback {
|
|
struct list_head list;
|
|
void (*func)(struct random_ready_callback *rdy);
|
|
struct module *owner;
|
|
};
|
|
|
|
extern void add_device_randomness(const void *, unsigned int);
|
|
extern void add_input_randomness(unsigned int type, unsigned int code,
|
|
unsigned int value);
|
|
extern void add_interrupt_randomness(int irq, int irq_flags);
|
|
|
|
extern void get_random_bytes(void *buf, int nbytes);
|
|
extern void get_blocking_random_bytes(void *buf, int nbytes);
|
|
extern int add_random_ready_callback(struct random_ready_callback *rdy);
|
|
extern void del_random_ready_callback(struct random_ready_callback *rdy);
|
|
extern void get_random_bytes_arch(void *buf, int nbytes);
|
|
void generate_random_uuid(unsigned char uuid_out[16]);
|
|
extern int random_int_secret_init(void);
|
|
|
|
#ifndef MODULE
|
|
extern const struct file_operations random_fops, urandom_fops;
|
|
#endif
|
|
|
|
unsigned int get_random_int(void);
|
|
unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
|
|
|
|
u32 prandom_u32(void);
|
|
void prandom_bytes(void *buf, size_t nbytes);
|
|
void prandom_seed(u32 seed);
|
|
void prandom_reseed_late(void);
|
|
|
|
struct rnd_state {
|
|
__u32 s1, s2, s3, s4;
|
|
};
|
|
|
|
u32 prandom_u32_state(struct rnd_state *state);
|
|
void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
|
|
|
|
/**
|
|
* prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
|
|
* @ep_ro: right open interval endpoint
|
|
*
|
|
* Returns a pseudo-random number that is in interval [0, ep_ro). Note
|
|
* that the result depends on PRNG being well distributed in [0, ~0U]
|
|
* u32 space. Here we use maximally equidistributed combined Tausworthe
|
|
* generator, that is, prandom_u32(). This is useful when requesting a
|
|
* random index of an array containing ep_ro elements, for example.
|
|
*
|
|
* Returns: pseudo-random number in interval [0, ep_ro)
|
|
*/
|
|
static inline u32 prandom_u32_max(u32 ep_ro)
|
|
{
|
|
return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
|
|
}
|
|
|
|
/*
|
|
* Handle minimum values for seeds
|
|
*/
|
|
static inline u32 __seed(u32 x, u32 m)
|
|
{
|
|
return (x < m) ? x + m : x;
|
|
}
|
|
|
|
/**
|
|
* prandom_seed_state - set seed for prandom_u32_state().
|
|
* @state: pointer to state structure to receive the seed.
|
|
* @seed: arbitrary 64-bit value to use as a seed.
|
|
*/
|
|
static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
|
|
{
|
|
u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
|
|
|
|
state->s1 = __seed(i, 2U);
|
|
state->s2 = __seed(i, 8U);
|
|
state->s3 = __seed(i, 16U);
|
|
state->s4 = __seed(i, 128U);
|
|
}
|
|
|
|
#ifdef CONFIG_ARCH_RANDOM
|
|
# include <asm/archrandom.h>
|
|
#else
|
|
static inline int arch_get_random_long(unsigned long *v)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline int arch_get_random_int(unsigned int *v)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline int arch_has_random(void)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline int arch_get_random_seed_long(unsigned long *v)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline int arch_get_random_seed_int(unsigned int *v)
|
|
{
|
|
return 0;
|
|
}
|
|
static inline int arch_has_random_seed(void)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
/* Pseudo random number generator from numerical recipes. */
|
|
static inline u32 next_pseudo_random32(u32 seed)
|
|
{
|
|
return seed * 1664525 + 1013904223;
|
|
}
|
|
|
|
#endif /* _LINUX_RANDOM_H */
|