diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/prandom.h | 17 | ||||
| -rw-r--r-- | include/linux/random.h | 7 |
2 files changed, 17 insertions, 7 deletions
diff --git a/include/linux/prandom.h b/include/linux/prandom.h index deace5fb4e62..78db003bc290 100644 --- a/include/linux/prandom.h +++ b/include/linux/prandom.h @@ -12,11 +12,13 @@ #include <linux/percpu.h> #include <linux/random.h> +/* Deprecated: use get_random_u32 instead. */ static inline u32 prandom_u32(void) { return get_random_u32(); } +/* Deprecated: use get_random_bytes instead. */ static inline void prandom_bytes(void *buf, size_t nbytes) { return get_random_bytes(buf, nbytes); @@ -37,17 +39,20 @@ void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state); * 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 a pseudo-random number that is in interval [0, ep_ro). This is + * useful when requesting a random index of an array containing ep_ro elements, + * for example. The result is somewhat biased when ep_ro is not a power of 2, + * so do not use this for cryptographic purposes. * * 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); + if (__builtin_constant_p(ep_ro <= 1U << 8) && ep_ro <= 1U << 8) + return (get_random_u8() * ep_ro) >> 8; + if (__builtin_constant_p(ep_ro <= 1U << 16) && ep_ro <= 1U << 16) + return (get_random_u16() * ep_ro) >> 16; + return ((u64)get_random_u32() * ep_ro) >> 32; } /* diff --git a/include/linux/random.h b/include/linux/random.h index 3fec206487f6..08322f700cdc 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -38,6 +38,8 @@ static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) { #endif void get_random_bytes(void *buf, size_t len); +u8 get_random_u8(void); +u16 get_random_u16(void); u32 get_random_u32(void); u64 get_random_u64(void); static inline unsigned int get_random_int(void) @@ -72,7 +74,8 @@ static inline unsigned long get_random_canary(void) return get_random_long() & CANARY_MASK; } -int __init random_init(const char *command_line); +void __init random_init_early(const char *command_line); +void __init random_init(void); bool rng_is_initialized(void); int wait_for_random_bytes(void); @@ -93,6 +96,8 @@ static inline int get_random_bytes_wait(void *buf, size_t nbytes) *out = get_random_ ## name(); \ return 0; \ } +declare_get_random_var_wait(u8, u8) +declare_get_random_var_wait(u16, u16) declare_get_random_var_wait(u32, u32) declare_get_random_var_wait(u64, u32) declare_get_random_var_wait(int, unsigned int) |