random: add new ioctl RNDRESEEDCRNG
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>
diff --git a/drivers/char/random.c b/drivers/char/random.c
index c621f84..58a2ff7 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -429,6 +429,7 @@
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]);
@@ -905,7 +906,8 @@
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))
@@ -1738,6 +1740,7 @@
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);
@@ -1924,6 +1927,14 @@
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;
}