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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 F1C42C04AB3 for ; Thu, 9 May 2019 14:13:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C85192085A for ; Thu, 9 May 2019 14:13:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726743AbfEIONL (ORCPT ); Thu, 9 May 2019 10:13:11 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46912 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726590AbfEIONK (ORCPT ); Thu, 9 May 2019 10:13:10 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hOjnI-000124-Gr; Thu, 09 May 2019 15:13:08 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hOjnI-0006M0-Ae; Thu, 09 May 2019 15:13:08 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Amit Klein" Date: Thu, 09 May 2019 15:08:17 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 03/10] inet: update the IP ID generation algorithm to higher standards. In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.67-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Amit Klein Commit 355b98553789 ("netns: provide pure entropy for net_hash_mix()") makes net_hash_mix() return a true 32 bits of entropy. When used in the IP ID generation algorithm, this has the effect of extending the IP ID generation key from 32 bits to 64 bits. However, net_hash_mix() is only used for IP ID generation starting with kernel version 4.1. Therefore, earlier kernels remain with 32-bit key no matter what the net_hash_mix() return value is. This change addresses the issue by explicitly extending the key to 64 bits for kernels older than 4.1. Signed-off-by: Amit Klein Signed-off-by: Ben Hutchings --- net/ipv4/route.c | 4 +++- net/ipv6/ip6_output.c | 3 +++ 2 files changed, 6 insertions(+), 1 deletion(-) --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -487,13 +487,15 @@ EXPORT_SYMBOL(ip_idents_reserve); void __ip_select_ident(struct iphdr *iph, int segs) { static u32 ip_idents_hashrnd __read_mostly; + static u32 ip_idents_hashrnd_extra __read_mostly; u32 hash, id; net_get_random_once(&ip_idents_hashrnd, sizeof(ip_idents_hashrnd)); + net_get_random_once(&ip_idents_hashrnd_extra, sizeof(ip_idents_hashrnd_extra)); hash = jhash_3words((__force u32)iph->daddr, (__force u32)iph->saddr, - iph->protocol, + iph->protocol ^ ip_idents_hashrnd_extra, ip_idents_hashrnd); id = ip_idents_reserve(hash, segs); iph->id = htons(id); --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -541,12 +541,15 @@ static void ip6_copy_metadata(struct sk_ static void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt) { static u32 ip6_idents_hashrnd __read_mostly; + static u32 ip6_idents_hashrnd_extra __read_mostly; u32 hash, id; net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd)); + net_get_random_once(&ip6_idents_hashrnd_extra, sizeof(ip6_idents_hashrnd_extra)); hash = __ipv6_addr_jhash(&rt->rt6i_dst.addr, ip6_idents_hashrnd); hash = __ipv6_addr_jhash(&rt->rt6i_src.addr, hash); + hash = jhash_1word(hash, ip6_idents_hashrnd_extra); id = ip_idents_reserve(hash, 1); fhdr->identification = htonl(id);