From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: [PATCH 3/4] random: printk notifications for urandom pool initialization Date: Sun, 3 Nov 2013 08:33:14 -0500 Message-ID: <1383485595-2020-4-git-send-email-tytso@mit.edu> References: <1383485595-2020-1-git-send-email-tytso@mit.edu> Cc: linux-kernel@vger.kernel.org, Theodore Ts'o To: linux-crypto@vger.kernel.org Return-path: Received: from imap.thunk.org ([74.207.234.97]:53764 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753427Ab3KCNdS (ORCPT ); Sun, 3 Nov 2013 08:33:18 -0500 In-Reply-To: <1383485595-2020-1-git-send-email-tytso@mit.edu> Sender: linux-crypto-owner@vger.kernel.org List-ID: Print a notification to the console when the nonblocking pool is initialized. Also printk a warning when a process tries reading from /dev/urandom before it is fully initialized. Signed-off-by: "Theodore Ts'o" --- drivers/char/random.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index b578c03..f553600 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -655,6 +655,9 @@ retry: r->entropy_total += nbits; if (!r->initialized && nbits > 0) { if (r->entropy_total > 128) { + if (r == &nonblocking_pool) + pr_notice("random: %s pool is initialized\n", + r->name); r->initialized = 1; r->entropy_total = 0; } @@ -1334,7 +1337,14 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) static ssize_t urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) { - int ret = extract_entropy_user(&nonblocking_pool, buf, nbytes); + 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); + + ret = extract_entropy_user(&nonblocking_pool, buf, nbytes); trace_urandom_read(8 * nbytes, ENTROPY_BITS(&nonblocking_pool), ENTROPY_BITS(&input_pool)); -- 1.7.12.rc0.22.gcdd159b