diff options
| -rw-r--r-- | drivers/char/random.c | 11 | ||||
| -rw-r--r-- | include/linux/random.h | 1 | ||||
| -rw-r--r-- | include/linux/timex.h | 14 | ||||
| -rw-r--r-- | init/main.c | 2 |
4 files changed, 22 insertions, 6 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 7737b5bd26af..7a744d391756 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -640,7 +640,7 @@ struct timer_rand_state { */ void add_device_randomness(const void *buf, unsigned int size) { - unsigned long time = get_cycles() ^ jiffies; + unsigned long time = random_get_entropy() ^ jiffies; mix_pool_bytes(&input_pool, buf, size, NULL); mix_pool_bytes(&input_pool, &time, sizeof(time), NULL); @@ -677,7 +677,7 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num) goto out; sample.jiffies = jiffies; - sample.cycles = get_cycles(); + sample.cycles = random_get_entropy(); sample.num = num; mix_pool_bytes(&input_pool, &sample, sizeof(sample), NULL); @@ -744,7 +744,7 @@ void add_interrupt_randomness(int irq, int irq_flags) struct fast_pool *fast_pool = &__get_cpu_var(irq_randomness); struct pt_regs *regs = get_irq_regs(); unsigned long now = jiffies; - __u32 input[4], cycles = get_cycles(); + __u32 input[4], cycles = random_get_entropy(); input[0] = cycles ^ jiffies; input[1] = irq; @@ -1459,12 +1459,11 @@ struct ctl_table random_table[] = { static u32 random_int_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned; -static int __init random_int_secret_init(void) +int random_int_secret_init(void) { get_random_bytes(random_int_secret, sizeof(random_int_secret)); return 0; } -late_initcall(random_int_secret_init); /* * Get a random word for internal kernel use only. Similar to urandom but @@ -1483,7 +1482,7 @@ unsigned int get_random_int(void) hash = get_cpu_var(get_random_int_hash); - hash[0] += current->pid + jiffies + get_cycles(); + hash[0] += current->pid + jiffies + random_get_entropy(); md5_transform(hash, random_int_secret); ret = hash[0]; put_cpu_var(get_random_int_hash); diff --git a/include/linux/random.h b/include/linux/random.h index 3b9377d6b7a5..6312dd9ba449 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -17,6 +17,7 @@ extern void add_interrupt_randomness(int irq, int irq_flags); extern void get_random_bytes(void *buf, int nbytes); 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; diff --git a/include/linux/timex.h b/include/linux/timex.h index dd3edd7dfc94..9d3f1a5b6178 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -64,6 +64,20 @@ #include <asm/timex.h> +#ifndef random_get_entropy +/* + * The random_get_entropy() function is used by the /dev/random driver + * in order to extract entropy via the relative unpredictability of + * when an interrupt takes places versus a high speed, fine-grained + * timing source or cycle counter. Since it will be occurred on every + * single interrupt, it must have a very low cost/overhead. + * + * By default we use get_cycles() for this purpose, but individual + * architectures may override this in their asm/timex.h header file. + */ +#define random_get_entropy() get_cycles() +#endif + /* * SHIFT_PLL is used as a dampening factor to define how much we * adjust the frequency correction for a given offset in PLL mode. diff --git a/init/main.c b/init/main.c index af310afbef28..63d3e8f2970c 100644 --- a/init/main.c +++ b/init/main.c @@ -76,6 +76,7 @@ #include <linux/elevator.h> #include <linux/sched_clock.h> #include <linux/context_tracking.h> +#include <linux/random.h> #include <asm/io.h> #include <asm/bugs.h> @@ -780,6 +781,7 @@ 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) |