Patch "random: print a warning for the first ten uninitialized random users" has been added to the 4.7-stable tree

Patch "random: print a warning for the first ten uninitialized random users" has been added to the 4.7-stable tree

[gregkh]

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 4.7-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-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 9b4d008787f864f17d008c9c15bbe8a0f7e2fc24 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
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@mit.edu>

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@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/char/random.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1462,12 +1462,16 @@ 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@mit.edu are

queue-4.7/random-print-a-warning-for-the-first-ten-uninitialized-random-users.patch
queue-4.7/random-properly-align-get_random_int_hash.patch
queue-4.7/random-initialize-the-non-blocking-pool-via-add_hwgenerator_randomness.patch
queue-4.7/random-add-interrupt-callback-to-vmbus-irq-handler.patch
queue-4.7/jbd2-make-journal-y2038-safe.patch