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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 CAC90C10F11 for ; Wed, 24 Apr 2019 18:12:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9AD0F20652 for ; Wed, 24 Apr 2019 18:12:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556129543; bh=NW9CxUf+rz3n5ng2Quu2wbGE1uAwkncSz3gCLdXVzSM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=taZ7Tl361Au3QY5024sr6yLd1ws/03rKtgucCzD+TKcp172eLZZHtiJfOeAmEWwXM aP9aRU0guqFX7xfARZfVn+4xNQcsh21jUtFeZIFy34mmp0Eg2NtsAE8pLYffuxYRUz 0Bw3VOvxOoBATufJiQ0uzmgo9tOYEz6Cub8bs2v8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387763AbfDXRM6 (ORCPT ); Wed, 24 Apr 2019 13:12:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:36876 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387733AbfDXRM4 (ORCPT ); Wed, 24 Apr 2019 13:12:56 -0400 Received: from localhost (62-193-50-229.as16211.net [62.193.50.229]) (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 0F6F421900; Wed, 24 Apr 2019 17:12:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556125975; bh=NW9CxUf+rz3n5ng2Quu2wbGE1uAwkncSz3gCLdXVzSM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rn94cWq9gjsNz6OL5ohkl53+Ji0c7zZJ5lj7mkTPvcR+2QKgTmCH6i/UsAWF9NI8L QWN/+T3WkWOFtWaCH7SelyDAS+xiQKvJOYQlVRwlyJQFyULv1ln6EmvSh4nx8PgHt5 iZhMIBZj1FBCdAZNH5xbE2B5T/nttl//lOs9xpa4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Amit Klein , Benny Pinkas , Pavel Emelyanov , "David S. Miller" Subject: [PATCH 3.18 049/104] netns: provide pure entropy for net_hash_mix() Date: Wed, 24 Apr 2019 19:09:06 +0200 Message-Id: <20190424170901.247037421@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190424170839.996641496@linuxfoundation.org> References: <20190424170839.996641496@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet [ Upstream commit 355b98553789b646ed97ad801a619ff898471b92 ] net_hash_mix() currently uses kernel address of a struct net, and is used in many places that could be used to reveal this address to a patient attacker, thus defeating KASLR, for the typical case (initial net namespace, &init_net is not dynamically allocated) I believe the original implementation tried to avoid spending too many cycles in this function, but security comes first. Also provide entropy regardless of CONFIG_NET_NS. Fixes: 0b4419162aa6 ("netns: introduce the net_hash_mix "salt" for hashes") Signed-off-by: Eric Dumazet Reported-by: Amit Klein Reported-by: Benny Pinkas Cc: Pavel Emelyanov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/net/net_namespace.h | 2 ++ include/net/netns/hash.h | 15 ++------------- net/core/net_namespace.c | 1 + 3 files changed, 5 insertions(+), 13 deletions(-) --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -54,6 +54,8 @@ struct net { #endif spinlock_t rules_mod_lock; + u32 hash_mix; + struct list_head list; /* list of network namespaces */ struct list_head cleanup_list; /* namespaces on death row */ struct list_head exit_list; /* Use only net_mutex */ --- a/include/net/netns/hash.h +++ b/include/net/netns/hash.h @@ -1,21 +1,10 @@ #ifndef __NET_NS_HASH_H__ #define __NET_NS_HASH_H__ -#include - -struct net; +#include static inline unsigned int net_hash_mix(struct net *net) { -#ifdef CONFIG_NET_NS - /* - * shift this right to eliminate bits, that are - * always zeroed - */ - - return (unsigned)(((unsigned long)net) >> L1_CACHE_SHIFT); -#else - return 0; -#endif + return net->hash_mix; } #endif --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -156,6 +156,7 @@ static __net_init int setup_net(struct n atomic_set(&net->count, 1); atomic_set(&net->passive, 1); + get_random_bytes(&net->hash_mix, sizeof(u32)); net->dev_base_seq = 1; net->user_ns = user_ns;