From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753123AbeE1Brp (ORCPT ); Sun, 27 May 2018 21:47:45 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:32815 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753009AbeE1BrQ (ORCPT ); Sun, 27 May 2018 21:47:16 -0400 X-ME-Proxy: X-ME-Proxy: X-ME-Proxy: X-ME-Proxy: X-ME-Proxy: X-ME-Proxy: X-ME-Sender: From: "Tobin C. Harding" To: Andrew Morton Cc: "Tobin C. Harding" , Linus Torvalds , Randy Dunlap , Steven Rostedt , Kees Cook , Anna-Maria Gleixner , "Theodore Ts'o" , Greg Kroah-Hartman , Arnd Bergmann , linux-kernel@vger.kernel.org Subject: [PATCH v6 3/4] vsprintf: Use hw RNG for ptr_key Date: Mon, 28 May 2018 11:46:41 +1000 Message-Id: <1527472002-11571-4-git-send-email-me@tobin.cc> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1527472002-11571-1-git-send-email-me@tobin.cc> References: <1527472002-11571-1-git-send-email-me@tobin.cc> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently we must wait for enough entropy to become available before hashed pointers can be printed. We can remove this wait by using the hw RNG if available. Use hw RNG to get keying material. Cc: Steven Rostedt (VMware) Suggested-by: Kees Cook Signed-off-by: Tobin C. Harding --- lib/vsprintf.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 23920c5ff728..1545a8aa26a9 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1693,8 +1693,16 @@ static struct random_ready_callback random_ready = { static int __init initialize_ptr_random(void) { - int ret = add_random_ready_callback(&random_ready); + int key_size = sizeof(ptr_key); + int ret; + + /* Use hw RNG if available */ + if (get_random_bytes_arch(&ptr_key, key_size) == key_size) { + static_branch_disable(¬_filled_random_ptr_key); + return 0; + } + ret = add_random_ready_callback(&random_ready); if (!ret) { return 0; } else if (ret == -EALREADY) { -- 2.7.4