| From d848e5f8e1ebdb227d045db55fe4f825e82965fa Mon Sep 17 00:00:00 2001 |
| From: Theodore Ts'o <tytso@mit.edu> |
| Date: Wed, 11 Apr 2018 16:32:17 -0400 |
| Subject: random: add new ioctl RNDRESEEDCRNG |
| |
| From: Theodore Ts'o <tytso@mit.edu> |
| |
| commit d848e5f8e1ebdb227d045db55fe4f825e82965fa upstream. |
| |
| Add a new ioctl which forces the the crng to be reseeded. |
| |
| Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
| Cc: stable@kernel.org |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/char/random.c | 13 ++++++++++++- |
| include/uapi/linux/random.h | 3 +++ |
| 2 files changed, 15 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/char/random.c |
| +++ b/drivers/char/random.c |
| @@ -436,6 +436,7 @@ 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, |
| __u8 out[CHACHA20_BLOCK_SIZE]); |
| @@ -873,7 +874,8 @@ static void _extract_crng(struct crng_st |
| 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)) |
| @@ -1668,6 +1670,7 @@ static int rand_initialize(void) |
| init_std_data(&input_pool); |
| init_std_data(&blocking_pool); |
| crng_initialize(&primary_crng); |
| + crng_global_init_time = jiffies; |
| |
| #ifdef CONFIG_NUMA |
| pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL|__GFP_NOFAIL); |
| @@ -1854,6 +1857,14 @@ static long random_ioctl(struct file *f, |
| 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; |
| } |
| --- a/include/uapi/linux/random.h |
| +++ b/include/uapi/linux/random.h |
| @@ -34,6 +34,9 @@ |
| /* 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; |