From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 6AAA6C433EF for ; Tue, 12 Jun 2018 18:45:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 136542089C for ; Tue, 12 Jun 2018 18:45:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 136542089C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933167AbeFLSpF (ORCPT ); Tue, 12 Jun 2018 14:45:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:37126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932343AbeFLSpD (ORCPT ); Tue, 12 Jun 2018 14:45:03 -0400 Received: from vmware.local.home (unknown [107.19.188.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 25D1520891; Tue, 12 Jun 2018 18:45:01 +0000 (UTC) Date: Tue, 12 Jun 2018 14:44:58 -0400 From: Steven Rostedt To: "Tobin C. Harding" Cc: "Theodore Ts'o" , Linus Torvalds , Randy Dunlap , Kees Cook , Anna-Maria Gleixner , Andrew Morton , Greg Kroah-Hartman , Arnd Bergmann , linux-kernel@vger.kernel.org Subject: Re: [PATCH v7 3/4] vsprintf: Use hw RNG for ptr_key Message-ID: <20180612144458.31930370@vmware.local.home> In-Reply-To: <1528763954-27731-4-git-send-email-me@tobin.cc> References: <1528763954-27731-1-git-send-email-me@tobin.cc> <1528763954-27731-4-git-send-email-me@tobin.cc> X-Mailer: Claws Mail 3.15.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 12 Jun 2018 10:39:13 +1000 "Tobin C. Harding" wrote: > 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) Reviewed-by: Steven Rostedt (VMware) -- Steve > 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 a48aaa79d352..c445f9f28760 100644 > --- a/lib/vsprintf.c > +++ b/lib/vsprintf.c > @@ -1675,8 +1675,16 @@ 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) {