4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Theodore Ts'o tytso@mit.edu
commit 4e00b339e264802851aff8e73cde7d24b57b18ce upstream.
On systems without sufficient boot randomness, no point spamming dmesg.
Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/char/random.c | 34 +++++++++++++++++++++++++++++++--- 1 file changed, 31 insertions(+), 3 deletions(-)
--- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -259,6 +259,7 @@ #include <linux/kmemcheck.h> #include <linux/workqueue.h> #include <linux/irq.h> +#include <linux/ratelimit.h> #include <linux/syscalls.h> #include <linux/completion.h> #include <linux/uuid.h> @@ -444,6 +445,16 @@ static void _crng_backtrack_protect(stru __u8 tmp[CHACHA20_BLOCK_SIZE], int used); static void process_random_ready_list(void);
+static struct ratelimit_state unseeded_warning = + RATELIMIT_STATE_INIT("warn_unseeded_randomness", HZ, 3); +static struct ratelimit_state urandom_warning = + RATELIMIT_STATE_INIT("warn_urandom_randomness", HZ, 3); + +static int ratelimit_disable __read_mostly; + +module_param_named(ratelimit_disable, ratelimit_disable, int, 0644); +MODULE_PARM_DESC(ratelimit_disable, "Disable random ratelimit suppression"); + /********************************************************************** * * OS independent entropy store. Here are the functions which handle @@ -886,6 +897,18 @@ static void crng_reseed(struct crng_stat process_random_ready_list(); wake_up_interruptible(&crng_init_wait); pr_notice("random: crng init done\n"); + if (unseeded_warning.missed) { + pr_notice("random: %d get_random_xx warning(s) missed " + "due to ratelimiting\n", + unseeded_warning.missed); + unseeded_warning.missed = 0; + } + if (urandom_warning.missed) { + pr_notice("random: %d urandom warning(s) missed " + "due to ratelimiting\n", + urandom_warning.missed); + urandom_warning.missed = 0; + } } spin_unlock_irqrestore(&crng->lock, flags); } @@ -1699,6 +1722,10 @@ static int rand_initialize(void) init_std_data(&blocking_pool); crng_initialize(&primary_crng); crng_global_init_time = jiffies; + if (ratelimit_disable) { + urandom_warning.interval = 0; + unseeded_warning.interval = 0; + } return 0; } early_initcall(rand_initialize); @@ -1766,9 +1793,10 @@ urandom_read(struct file *file, char __u
if (!crng_ready() && maxwarn > 0) { maxwarn--; - printk(KERN_NOTICE "random: %s: uninitialized urandom read " - "(%zd bytes read)\n", - current->comm, nbytes); + if (__ratelimit(&urandom_warning)) + printk(KERN_NOTICE "random: %s: uninitialized " + "urandom read (%zd bytes read)\n", + current->comm, nbytes); spin_lock_irqsave(&primary_crng.lock, flags); crng_init_cnt = 0; spin_unlock_irqrestore(&primary_crng.lock, flags);