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Commit d848e5f8 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

random: add new ioctl RNDRESEEDCRNG 



Add a new ioctl which forces the the crng to be reseeded.

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
parent 0bb29a84

drivers/char/random.c

+12 −1
Original line number Diff line number Diff line
@@ -429,6 +429,7 @@ struct crng_state primary_crng = { 
static int crng_init = 0;

#define crng_ready() (likely(crng_init > 1))

static int crng_init_cnt = 0;

static unsigned long crng_global_init_time = 0;

#define CRNG_INIT_CNT_THRESH (2*CHACHA20_KEY_SIZE)

static void _extract_crng(struct crng_state *crng,

			  __u32 out[CHACHA20_BLOCK_WORDS]);
@@ -933,7 +934,8 @@ static void _extract_crng(struct crng_state *crng, 
	unsigned long v, flags;



	if (crng_ready() &&

	    time_after(jiffies, crng->init_time + CRNG_RESEED_INTERVAL))

	    (time_after(crng_global_init_time, crng->init_time) ||

	     time_after(jiffies, crng->init_time + CRNG_RESEED_INTERVAL)))

		crng_reseed(crng, crng == &primary_crng ? &input_pool : NULL);

	spin_lock_irqsave(&crng->lock, flags);

	if (arch_get_random_long(&v))
@@ -1757,6 +1759,7 @@ static int rand_initialize(void) 
	init_std_data(&input_pool);

	init_std_data(&blocking_pool);

	crng_initialize(&primary_crng);

	crng_global_init_time = jiffies;

	return 0;

}

early_initcall(rand_initialize);
@@ -1930,6 +1933,14 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) 
		input_pool.entropy_count = 0;

		blocking_pool.entropy_count = 0;

		return 0;

	case RNDRESEEDCRNG:

		if (!capable(CAP_SYS_ADMIN))

			return -EPERM;

		if (crng_init < 2)

			return -ENODATA;

		crng_reseed(&primary_crng, NULL);

		crng_global_init_time = jiffies - 1;

		return 0;

	default:

		return -EINVAL;

	}

include/uapi/linux/random.h

+3 −0
Original line number Diff line number Diff line
@@ -35,6 +35,9 @@ 
/* Clear the entropy pool and associated counters.  (Superuser only.) */

#define RNDCLEARPOOL	_IO( 'R', 0x06 )



/* Reseed CRNG.  (Superuser only.) */

#define RNDRESEEDCRNG	_IO( 'R', 0x07 )



struct rand_pool_info {

	int	entropy_count;

	int	buf_size;