From d848e5f8e1ebdb227d045db55fe4f825e82965fa Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 11 Apr 2018 16:32:17 -0400 Subject: [PATCH] random: add new ioctl RNDRESEEDCRNG Add a new ioctl which forces the the crng to be reseeded. Signed-off-by: Theodore Ts'o Cc: stable@kernel.org --- drivers/char/random.c | 13 ++++++++++++- include/uapi/linux/random.h | 3 +++ 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 898233f594b4..3cd3aae24d6d 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -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; } diff --git a/include/uapi/linux/random.h b/include/uapi/linux/random.h index c34f4490d025..26ee91300e3e 100644 --- a/include/uapi/linux/random.h +++ b/include/uapi/linux/random.h @@ -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; -- 2.30.2