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=-9.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 2F43BC433E3 for ; Thu, 20 Aug 2020 08:53:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 049A622B49 for ; Thu, 20 Aug 2020 08:53:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="RgxlXtej" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727070AbgHTIxV (ORCPT ); Thu, 20 Aug 2020 04:53:21 -0400 Received: from mo4-p03-ob.smtp.rzone.de ([85.215.255.103]:10845 "EHLO mo4-p03-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726820AbgHTIxF (ORCPT ); Thu, 20 Aug 2020 04:53:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1597913578; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=GDQNYNV6d6QkhkBWKYYphP4XWPgjkJNiEbogpLbfwhg=; b=RgxlXtej48iO5AtGGK5Q4kC1kyL9tCOVvyUAkfjfLt3DyGLVxFH2UtjeNdFNDTknxE zvguA3ym0wnAevXvpNYr1rkVaULER+TBP3Vt2QaMIvdnw4XPkV2Ab0IEyL+x3QNRAGRd TvxHlhniRRk7EED4bm+JDuU6X7q7jaMbgS+p1I78E0PZ2r/h/oV2Z2T+naen0XUaoOhX MR3lzJEt4Vft3J4j7ikbeqr6f83HACMW13y9rC85CuycV8wJ4oSj1rbyhwMQVATn4J84 tI0iu2EoG1GRLksOHOpqSqDNiqR3tgs31CW1fAadMkvzHEdFQlkCA/IJYfJaKADq9+aS xVug== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xm0dNS3IdRAZAL+p6A==" X-RZG-CLASS-ID: mo00 Received: from positron.chronox.de by smtp.strato.de (RZmta 46.10.7 DYNA|AUTH) with ESMTPSA id 002e9aw7K8nNBSc (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Thu, 20 Aug 2020 10:49:23 +0200 (CEST) From: Stephan =?ISO-8859-1?Q?M=FCller?= To: 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 , Randy Dunlap , Julia Lawall , Dan Carpenter Subject: [PATCH v32 09/12] LRNG - add Jitter RNG fast noise source Date: Thu, 20 Aug 2020 10:44:07 +0200 Message-ID: <798960573.0ifERbkFSE@positron.chronox.de> In-Reply-To: <2544450.mvXUDI8C0e@positron.chronox.de> References: <2544450.mvXUDI8C0e@positron.chronox.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="iso-8859-1" Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org The Jitter RNG fast noise source implemented as part of the kernel crypto API is queried for 256 bits of entropy at the time the seed buffer managed by the LRNG is about to be filled. CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange Reviewed-by: Marcelo Henrique Cerri Reviewed-by: Roman Drahtmueller Tested-by: Roman Drahtm=FCller Tested-by: Marcelo Henrique Cerri Tested-by: Neil Horman Signed-off-by: Stephan Mueller =2D-- drivers/char/lrng/Kconfig | 12 +++++ drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_jent.c | 88 +++++++++++++++++++++++++++++++++++ 3 files changed, 101 insertions(+) create mode 100644 drivers/char/lrng/lrng_jent.c diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig index ba3d84cd0676..66a775a8f912 100644 =2D-- a/drivers/char/lrng/Kconfig +++ b/drivers/char/lrng/Kconfig @@ -95,4 +95,16 @@ config LRNG_KCAPI provided by the selected kernel crypto API RNG. endif # LRNG_DRNG_SWITCH =20 +config LRNG_JENT + bool "Enable Jitter RNG as LRNG Seed Source" + depends on CRYPTO + select CRYPTO_JITTERENTROPY + help + The Linux RNG may use the Jitter RNG as noise source. Enabling + this option enables the use of the Jitter RNG. Its default + entropy level is 16 bits of entropy per 256 data bits delivered + by the Jitter RNG. This entropy level can be changed at boot + time or at runtime with the lrng_base.jitterrng configuration + variable. + endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index 94b2dfb2dfdb..4f5b6f38f0c4 100644 =2D-- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_SYSCTL) +=3D lrng_proc.o obj-$(CONFIG_LRNG_DRNG_SWITCH) +=3D lrng_switch.o obj-$(CONFIG_LRNG_DRBG) +=3D lrng_drbg.o obj-$(CONFIG_LRNG_KCAPI) +=3D lrng_kcapi.o +obj-$(CONFIG_LRNG_JENT) +=3D lrng_jent.o diff --git a/drivers/char/lrng/lrng_jent.c b/drivers/char/lrng/lrng_jent.c new file mode 100644 index 000000000000..225505271fcb =2D-- /dev/null +++ b/drivers/char/lrng/lrng_jent.c @@ -0,0 +1,88 @@ +// 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 indic= ating + * 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 =3D 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"); + +/** + * lrng_get_jent() - 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 + */ +static struct rand_data *lrng_jent_state; + +u32 lrng_get_jent(u8 *outbuf, unsigned int outbuflen) +{ + int ret; + u32 ent_bits =3D jitterrng; + unsigned long flags; + static DEFINE_SPINLOCK(lrng_jent_lock); + static int lrng_jent_initialized =3D 0; + + spin_lock_irqsave(&lrng_jent_lock, flags); + + if (!ent_bits || (lrng_jent_initialized =3D=3D -1)) { + spin_unlock_irqrestore(&lrng_jent_lock, flags); + return 0; + } + + if (!lrng_jent_initialized) { + lrng_jent_state =3D jent_lrng_entropy_collector(); + if (!lrng_jent_state) { + jitterrng =3D 0; + lrng_jent_initialized =3D -1; + spin_unlock_irqrestore(&lrng_jent_lock, flags); + pr_info("Jitter RNG unusable on current system\n"); + return 0; + } + lrng_jent_initialized =3D 1; + pr_debug("Jitter RNG working on current system\n"); + } + ret =3D 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 !=3D LRNG_DRNG_SECURITY_STRENGTH_BYTES) + ent_bits =3D (ent_bits * outbuflen<<3) / + LRNG_DRNG_SECURITY_STRENGTH_BITS; + /* Cap entropy to buffer size in bits */ + ent_bits =3D 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); +} =2D-=20 2.26.2