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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3D0AC282DD for ; Fri, 10 Jan 2020 00:25:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 656642080D for ; Fri, 10 Jan 2020 00:25:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="PoXKKEJJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730176AbgAJAZV (ORCPT ); Thu, 9 Jan 2020 19:25:21 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:34700 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730169AbgAJAZV (ORCPT ); Thu, 9 Jan 2020 19:25:21 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To: Subject:Sender:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=/f2runeNBw6RnPGtAhc9+ZVQ9RgfOZH+rYsz78EvOG8=; b=PoXKKEJJei3qRhn4QaYaTkEfx rYg+orz4hpYeb15+KTic/aiDGubbxAuzN6jjkltLsHmaXtQNxOUyLzf17Eeg5jJQIvgExe4IJfMFu y61G6O4Upe3zvP/KH+35vVTPBFjfSuaUEAdtjpb/my9/bfDjTs+FloAB7fBUGhN7MCSucmLpndFND 4+9gfZJ4gtbw9kwkZ/R0or5HRFfta9TtcZi03VD31opqR7aY9DKWdIRsxiUUkz1BZmozLu48j2EFt qhMqOa8wS6Jab0+GxuJAkr2cRzgxfLfXZ8VDlxSmQBTtAIRunNPNARC0OLRfYhlBASnYOH6sO5lOQ 64nXFY7YA==; Received: from [2601:1c0:6280:3f0::ed68] by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1ipi6b-0004L4-8i; Fri, 10 Jan 2020 00:24:49 +0000 Subject: Re: [PATCH v27 09/12] LRNG - add Jitter RNG fast noise source To: =?UTF-8?Q?Stephan_M=c3=bcller?= , Arnd Bergmann Cc: Greg Kroah-Hartman , linux-crypto@vger.kernel.org, LKML , linux-api@vger.kernel.org, "Eric W. Biederman" , "Alexander E. Patrakov" , "Ahmed S. Darwish" , "Theodore Y. Ts'o" , Willy Tarreau , Matthew Garrett , Vito Caputo , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , zhangjs , Andy Lutomirski , Florian Weimer , Lennart Poettering , Nicolai Stange , "Peter, Matthias" , Marcelo Henrique Cerri , Roman Drahtmueller , Neil Horman , Julia Lawall References: <6157374.ptSnyUpaCn@positron.chronox.de> <2722222.P16TYeLAVu@positron.chronox.de> <2641155.iNH938UiKq@positron.chronox.de> <6341883.UacF4FzDma@positron.chronox.de> From: Randy Dunlap Message-ID: <0ba976fa-fed1-4720-c039-043160dbce9e@infradead.org> Date: Thu, 9 Jan 2020 16:24:47 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: <6341883.UacF4FzDma@positron.chronox.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Hi, On 1/9/20 12:34 AM, Stephan Müller wrote: > --- > drivers/char/lrng/Kconfig | 11 +++++ > drivers/char/lrng/Makefile | 1 + > drivers/char/lrng/lrng_jent.c | 87 +++++++++++++++++++++++++++++++++++ > 3 files changed, 99 insertions(+) > create mode 100644 drivers/char/lrng/lrng_jent.c > > diff --git a/drivers/char/lrng/lrng_jent.c b/drivers/char/lrng/lrng_jent.c > new file mode 100644 > index 000000000000..97c0d192e9c8 > --- /dev/null > +++ b/drivers/char/lrng/lrng_jent.c > @@ -0,0 +1,87 @@ > +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause > +/* > + * LRNG Fast Noise Source: Jitter RNG > + * > + * Copyright (C) 2016 - 2020, Stephan Mueller > + */ > + > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include > +#include > + > +#include "lrng_internal.h" > + > +/* > + * Estimated entropy of data is a 16th of LRNG_DRNG_SECURITY_STRENGTH_BITS. > + * Albeit a full entropy assessment is provided for the noise source indicating > + * that it provides high entropy rates and considering that it deactivates > + * when it detects insufficient hardware, the chosen under estimation of > + * entropy is considered to be acceptable to all reviewers. > + */ > +static u32 jitterrng = LRNG_DRNG_SECURITY_STRENGTH_BITS>>4; > +module_param(jitterrng, uint, 0644); > +MODULE_PARM_DESC(jitterrng, "Entropy in bits of 256 data bits from Jitter " > + "RNG noise source"); > + > +/** > + * Get Jitter RNG entropy > + * > + * @outbuf buffer to store entropy > + * @outbuflen length of buffer > + * @return > 0 on success where value provides the added entropy in bits > + * 0 if no fast source was available > + */ Don't begin the comment block with /** or convert it to Linux kernel-doc notation format. > +static struct rand_data *lrng_jent_state; > + > +u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen) > +{ > + int ret; > + u32 ent_bits = jitterrng; > + unsigned long flags; > + static DEFINE_SPINLOCK(lrng_jent_lock); > + static int lrng_jent_initialized = 0; > + > + spin_lock_irqsave(&lrng_jent_lock, flags); > + > + if (!ent_bits || (lrng_jent_initialized == -1)) { > + spin_unlock_irqrestore(&lrng_jent_lock, flags); > + return 0; > + } > + > + if (!lrng_jent_initialized) { > + lrng_jent_state = jent_lrng_entropy_collector(); > + if (!lrng_jent_state) { > + jitterrng = 0; > + lrng_jent_initialized = -1; > + spin_unlock_irqrestore(&lrng_jent_lock, flags); > + pr_info("Jitter RNG unusable on current system\n"); > + return 0; > + } > + lrng_jent_initialized = 1; > + pr_debug("Jitter RNG working on current system\n"); > + } > + ret = jent_read_entropy(lrng_jent_state, outbuf, outbuflen); > + spin_unlock_irqrestore(&lrng_jent_lock, flags); > + > + if (ret) { > + pr_debug("Jitter RNG failed with %d\n", ret); > + return 0; > + } > + > + /* Obtain entropy statement */ > + if (outbuflen != LRNG_DRNG_SECURITY_STRENGTH_BYTES) > + ent_bits = (ent_bits * outbuflen<<3) / > + LRNG_DRNG_SECURITY_STRENGTH_BITS; > + /* Cap entropy to buffer size in bits */ > + ent_bits = min_t(u32, ent_bits, outbuflen<<3); > + pr_debug("obtained %u bits of entropy from Jitter RNG noise source\n", > + ent_bits); > + > + return ent_bits; > +} > + > +u32 lrng_jent_entropylevel(void) > +{ > + return min_t(u32, jitterrng, LRNG_DRNG_SECURITY_STRENGTH_BITS); > +} > thanks. -- ~Randy