diff options
| -rw-r--r-- | drivers/char/random.c | 84 | ||||
| -rw-r--r-- | include/linux/random.h | 1 | ||||
| -rw-r--r-- | init/main.c | 1 |
3 files changed, 43 insertions, 43 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index d6876d506220..08d1dd58c0d2 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2042,63 +2042,65 @@ struct ctl_table random_table[] = { }; #endif /* CONFIG_SYSCTL */ -static u32 random_int_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned; - -int random_int_secret_init(void) -{ - get_random_bytes(random_int_secret, sizeof(random_int_secret)); - return 0; -} - -static DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash) - __aligned(sizeof(unsigned long)); +struct batched_entropy { + union { + unsigned long entropy_long[CHACHA20_BLOCK_SIZE / sizeof(unsigned long)]; + unsigned int entropy_int[CHACHA20_BLOCK_SIZE / sizeof(unsigned int)]; + }; + unsigned int position; +}; /* - * Get a random word for internal kernel use only. Similar to urandom but - * with the goal of minimal entropy pool depletion. As a result, the random - * value is not cryptographically secure but for several uses the cost of - * depleting entropy is too high + * Get a random word for internal kernel use only. The quality of the random + * number is either as good as RDRAND or as good as /dev/urandom, with the + * goal of being quite fast and not depleting entropy. */ -unsigned int get_random_int(void) +static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_long); +unsigned long get_random_long(void) { - __u32 *hash; - unsigned int ret; + unsigned long ret; + struct batched_entropy *batch; - if (arch_get_random_int(&ret)) + if (arch_get_random_long(&ret)) return ret; - hash = get_cpu_var(get_random_int_hash); - - hash[0] += current->pid + jiffies + random_get_entropy(); - md5_transform(hash, random_int_secret); - ret = hash[0]; - put_cpu_var(get_random_int_hash); - + batch = &get_cpu_var(batched_entropy_long); + if (batch->position % ARRAY_SIZE(batch->entropy_long) == 0) { + extract_crng((u8 *)batch->entropy_long); + batch->position = 0; + } + ret = batch->entropy_long[batch->position++]; + put_cpu_var(batched_entropy_long); return ret; } -EXPORT_SYMBOL(get_random_int); +EXPORT_SYMBOL(get_random_long); -/* - * Same as get_random_int(), but returns unsigned long. - */ -unsigned long get_random_long(void) +#if BITS_PER_LONG == 32 +unsigned int get_random_int(void) { - __u32 *hash; - unsigned long ret; + return get_random_long(); +} +#else +static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_int); +unsigned int get_random_int(void) +{ + unsigned int ret; + struct batched_entropy *batch; - if (arch_get_random_long(&ret)) + if (arch_get_random_int(&ret)) return ret; - hash = get_cpu_var(get_random_int_hash); - - hash[0] += current->pid + jiffies + random_get_entropy(); - md5_transform(hash, random_int_secret); - ret = *(unsigned long *)hash; - put_cpu_var(get_random_int_hash); - + batch = &get_cpu_var(batched_entropy_int); + if (batch->position % ARRAY_SIZE(batch->entropy_int) == 0) { + extract_crng((u8 *)batch->entropy_int); + batch->position = 0; + } + ret = batch->entropy_int[batch->position++]; + put_cpu_var(batched_entropy_int); return ret; } -EXPORT_SYMBOL(get_random_long); +#endif +EXPORT_SYMBOL(get_random_int); /** * randomize_page - Generate a random, page aligned address diff --git a/include/linux/random.h b/include/linux/random.h index 7bd2403e4fef..16ab429735a7 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -37,7 +37,6 @@ extern void get_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); -extern int random_int_secret_init(void); #ifndef MODULE extern const struct file_operations random_fops, urandom_fops; diff --git a/init/main.c b/init/main.c index 2858be732f6d..ae3996ae9bac 100644 --- a/init/main.c +++ b/init/main.c @@ -868,7 +868,6 @@ static void __init do_basic_setup(void) do_ctors(); usermodehelper_enable(); do_initcalls(); - random_int_secret_init(); } static void __init do_pre_smp_initcalls(void) |