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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D168C433F5 for ; Wed, 27 Apr 2022 06:53:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358370AbiD0G4T (ORCPT ); Wed, 27 Apr 2022 02:56:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351656AbiD0G4Q (ORCPT ); Wed, 27 Apr 2022 02:56:16 -0400 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 0EF13DCE; Tue, 26 Apr 2022 23:53:04 -0700 (PDT) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 23R6qosB002127; Wed, 27 Apr 2022 08:52:50 +0200 From: Willy Tarreau To: netdev@vger.kernel.org Cc: David Miller , Jakub Kicinski , Eric Dumazet , Moshe Kol , Yossi Gilad , Amit Klein , linux-kernel@vger.kernel.org Subject: [PATCH net 3/7] tcp: resalt the secret every 10 seconds Date: Wed, 27 Apr 2022 08:52:29 +0200 Message-Id: <20220427065233.2075-4-w@1wt.eu> X-Mailer: git-send-email 2.17.5 In-Reply-To: <20220427065233.2075-1-w@1wt.eu> References: <20220427065233.2075-1-w@1wt.eu> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet In order to limit the ability for an observer to recognize the source ports sequence used to contact a set of destinations, we should periodically shuffle the secret. 10 seconds looks effective enough without causing particular issues. Cc: Moshe Kol Cc: Yossi Gilad Cc: Amit Klein Tested-by: Willy Tarreau Signed-off-by: Eric Dumazet --- net/core/secure_seq.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c index 2cdd43a63f64..200ab4686275 100644 --- a/net/core/secure_seq.c +++ b/net/core/secure_seq.c @@ -22,6 +22,8 @@ static siphash_aligned_key_t net_secret; static siphash_aligned_key_t ts_secret; +#define EPHEMERAL_PORT_SHUFFLE_PERIOD (10 * HZ) + static __always_inline void net_secret_init(void) { net_get_random_once(&net_secret, sizeof(net_secret)); @@ -101,10 +103,12 @@ u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, struct in6_addr saddr; struct in6_addr daddr; __be16 dport; + unsigned int timeseed; } __aligned(SIPHASH_ALIGNMENT) combined = { .saddr = *(struct in6_addr *)saddr, .daddr = *(struct in6_addr *)daddr, - .dport = dport + .dport = dport, + .timeseed = jiffies / EPHEMERAL_PORT_SHUFFLE_PERIOD, }; net_secret_init(); return siphash(&combined, offsetofend(typeof(combined), dport), @@ -145,8 +149,10 @@ EXPORT_SYMBOL_GPL(secure_tcp_seq); u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) { net_secret_init(); - return siphash_3u32((__force u32)saddr, (__force u32)daddr, - (__force u16)dport, &net_secret); + return siphash_4u32((__force u32)saddr, (__force u32)daddr, + (__force u16)dport, + jiffies / EPHEMERAL_PORT_SHUFFLE_PERIOD, + &net_secret); } EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); #endif -- 2.17.5