4.9-stable review patch. If anyone has any objections, please let me know.
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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]); @@ -900,7 +901,8 @@ 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)) @@ -1689,6 +1691,7 @@ 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); @@ -1862,6 +1865,14 @@ 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;