4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Theodore Ts'o <tytso@xxxxxxx>
commit 4e00b339e264802851aff8e73cde7d24b57b18ce upstream.
On systems without sufficient boot randomness, no point spamming dmesg.
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
