This is a note to let you know that I've just added the patch titled
random: print a warning for the first ten uninitialized random users
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
random-print-a-warning-for-the-first-ten-uninitialized-random-users.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9b4d008787f864f17d008c9c15bbe8a0f7e2fc24 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@xxxxxxx>
Date: Mon, 13 Jun 2016 10:10:51 -0400
Subject: random: print a warning for the first ten uninitialized random users
From: Theodore Ts'o <tytso@xxxxxxx>
commit 9b4d008787f864f17d008c9c15bbe8a0f7e2fc24 upstream.
Since systemd is consistently using /dev/urandom before it is
initialized, we can't see the other potentially dangerous users of
/dev/urandom immediately after boot. So print the first ten such
complaints instead.
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/char/random.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1460,12 +1460,16 @@ random_read(struct file *file, char __us
static ssize_t
urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
{
+ static int maxwarn = 10;
int ret;
- if (unlikely(nonblocking_pool.initialized == 0))
- printk_once(KERN_NOTICE "random: %s urandom read "
- "with %d bits of entropy available\n",
- current->comm, nonblocking_pool.entropy_total);
+ if (unlikely(nonblocking_pool.initialized == 0) &&
+ maxwarn > 0) {
+ maxwarn--;
+ printk(KERN_NOTICE "random: %s: uninitialized urandom read "
+ "(%zd bytes read, %d bits of entropy available)\n",
+ current->comm, nbytes, nonblocking_pool.entropy_total);
+ }
nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3));
ret = extract_entropy_user(&nonblocking_pool, buf, nbytes);
Patches currently in stable-queue which might be from tytso@xxxxxxx are
queue-4.4/random-print-a-warning-for-the-first-ten-uninitialized-random-users.patch
queue-4.4/random-properly-align-get_random_int_hash.patch
queue-4.4/random-initialize-the-non-blocking-pool-via-add_hwgenerator_randomness.patch
queue-4.4/random-add-interrupt-callback-to-vmbus-irq-handler.patch
queue-4.4/jbd2-make-journal-y2038-safe.patch
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