From patchwork Wed Jun 7 23:26:04 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 9773249 X-Patchwork-Delegate: herbert@gondor.apana.org.au Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2804360393 for ; Wed, 7 Jun 2017 23:26:41 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1C182283AD for ; Wed, 7 Jun 2017 23:26:41 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 10ED32848D; Wed, 7 Jun 2017 23:26:41 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A2A0C2847A for ; Wed, 7 Jun 2017 23:26:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753486AbdFGX0g (ORCPT ); Wed, 7 Jun 2017 19:26:36 -0400 Received: from frisell.zx2c4.com ([192.95.5.64]:54805 "EHLO frisell.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753485AbdFGX0f (ORCPT ); Wed, 7 Jun 2017 19:26:35 -0400 Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 7a7ba127; Wed, 7 Jun 2017 23:26:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=from:to:cc :subject:date:message-id:in-reply-to:references; s=mail; bh=Wx3E csjwLHV0PI0DLBl591GMgPQ=; b=SFkXUI74my0uKPdaW2Jm9XNquGMA26j91Cs4 QZuPpAEQ7HrCOBr88zZaV/OO5MlkB2WgWt1a+N9neN3ZjPdgSebhpXiqoPIstlCC iWgVIwBrbG0LTRuC5NULKX1ZImcZX0HsqcFgi1mq94I4yChNftMYTCO5P98Cf+0U 6vNIHXPFdgQqUeek8kdOgPE0IY0BwhEjFEW3IdzcB6F2HZolUf/MSEzaobE6Nedt Y/rBsR2xdrxBNeeusZ0YoN8FzMkz/ilmmgEDkoksDrkSRMoatE8klPmvspiEi3KX jGho0CPDI6scKDjSpynLZZptfE08FNJirhz002qukN8IzDwI+w== Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 93d03c60 (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256:NO); Wed, 7 Jun 2017 23:26:04 +0000 (UTC) From: "Jason A. Donenfeld" To: Theodore Ts'o , Linux Crypto Mailing List , LKML , kernel-hardening@lists.openwall.com, Greg Kroah-Hartman , Eric Biggers , Linus Torvalds , David Miller Cc: "Jason A. Donenfeld" Subject: [PATCH v5 10/13] net/neighbor: use get_random_u32 for 32-bit hash random Date: Thu, 8 Jun 2017 01:26:04 +0200 Message-Id: <20170607232607.26870-11-Jason@zx2c4.com> In-Reply-To: <20170607232607.26870-1-Jason@zx2c4.com> References: <20170607232607.26870-1-Jason@zx2c4.com> Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Using get_random_u32 here is faster, more fitting of the use case, and just as cryptographically secure. It also has the benefit of providing better randomness at early boot, which is when many of these structures are assigned. Signed-off-by: Jason A. Donenfeld Cc: David Miller --- net/core/neighbour.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/core/neighbour.c b/net/core/neighbour.c index d274f81fcc2c..9784133b0cdb 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -312,8 +312,7 @@ static struct neighbour *neigh_alloc(struct neigh_table *tbl, struct net_device static void neigh_get_hash_rnd(u32 *x) { - get_random_bytes(x, sizeof(*x)); - *x |= 1; + *x = get_random_u32() | 1; } static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift)