From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755731AbcKNEEZ (ORCPT ); Sun, 13 Nov 2016 23:04:25 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:44962 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751950AbcKNCEM (ORCPT ); Sun, 13 Nov 2016 21:04:12 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Theodore Ts'o" Date: Mon, 14 Nov 2016 00:14:20 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 010/346] random: print a warning for the first ten uninitialized random users In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.39-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o 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 Signed-off-by: Ben Hutchings --- drivers/char/random.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1379,12 +1379,16 @@ 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);