From patchwork Thu Apr 28 12:39:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Willy Tarreau X-Patchwork-Id: 12830624 X-Patchwork-Delegate: kuba@kernel.org 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 4270AC433FE for ; Thu, 28 Apr 2022 12:41:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346468AbiD1MoT (ORCPT ); Thu, 28 Apr 2022 08:44:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45482 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346445AbiD1MoK (ORCPT ); Thu, 28 Apr 2022 08:44:10 -0400 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 42101631D; Thu, 28 Apr 2022 05:40:55 -0700 (PDT) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 23SCeE1I007480; Thu, 28 Apr 2022 14:40:14 +0200 From: Willy Tarreau To: netdev@vger.kernel.org Cc: David Miller , Jakub Kicinski , Eric Dumazet , Moshe Kol , Yossi Gilad , Amit Klein , "Jason A . Donenfeld" , linux-kernel@vger.kernel.org, Willy Tarreau Subject: [PATCH v2 net 1/7] secure_seq: use the 64 bits of the siphash for port offset calculation Date: Thu, 28 Apr 2022 14:39:55 +0200 Message-Id: <20220428124001.7428-2-w@1wt.eu> X-Mailer: git-send-email 2.17.5 In-Reply-To: <20220428124001.7428-1-w@1wt.eu> References: <20220428124001.7428-1-w@1wt.eu> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org SipHash replaced MD5 in secure_ipv{4,6}_port_ephemeral() via commit 7cd23e5300c1 ("secure_seq: use SipHash in place of MD5"), but the output remained truncated to 32-bit only. In order to exploit more bits from the hash, let's make the functions return the full 64-bit of siphash_3u32(). We also make sure the port offset calculation in __inet_hash_connect() remains done on 32-bit to avoid the need for div_u64_rem() and an extra cost on 32-bit systems. Cc: Jason A. Donenfeld Cc: Moshe Kol Cc: Yossi Gilad Cc: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau Acked-by: Jason A. Donenfeld # For secure_seq.[ch] --- include/net/inet_hashtables.h | 2 +- include/net/secure_seq.h | 4 ++-- net/core/secure_seq.c | 4 ++-- net/ipv4/inet_hashtables.c | 10 ++++++---- net/ipv6/inet6_hashtables.c | 4 ++-- 5 files changed, 13 insertions(+), 11 deletions(-) diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h index f72ec113ae56..98e1ec1a14f0 100644 --- a/include/net/inet_hashtables.h +++ b/include/net/inet_hashtables.h @@ -425,7 +425,7 @@ static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr) } int __inet_hash_connect(struct inet_timewait_death_row *death_row, - struct sock *sk, u32 port_offset, + struct sock *sk, u64 port_offset, int (*check_established)(struct inet_timewait_death_row *, struct sock *, __u16, struct inet_timewait_sock **)); diff --git a/include/net/secure_seq.h b/include/net/secure_seq.h index d7d2495f83c2..dac91aa38c5a 100644 --- a/include/net/secure_seq.h +++ b/include/net/secure_seq.h @@ -4,8 +4,8 @@ #include -u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport); -u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, +u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport); +u64 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, __be16 dport); u32 secure_tcp_seq(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport); diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c index 9b8443774449..55aa5cc258e3 100644 --- a/net/core/secure_seq.c +++ b/net/core/secure_seq.c @@ -94,7 +94,7 @@ u32 secure_tcpv6_seq(const __be32 *saddr, const __be32 *daddr, } EXPORT_SYMBOL(secure_tcpv6_seq); -u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, +u64 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, __be16 dport) { const struct { @@ -142,7 +142,7 @@ u32 secure_tcp_seq(__be32 saddr, __be32 daddr, } EXPORT_SYMBOL_GPL(secure_tcp_seq); -u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) +u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) { net_secret_init(); return siphash_3u32((__force u32)saddr, (__force u32)daddr, diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 17440840a791..9d24d9319f3d 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -504,7 +504,7 @@ static int __inet_check_established(struct inet_timewait_death_row *death_row, return -EADDRNOTAVAIL; } -static u32 inet_sk_port_offset(const struct sock *sk) +static u64 inet_sk_port_offset(const struct sock *sk) { const struct inet_sock *inet = inet_sk(sk); @@ -734,7 +734,7 @@ EXPORT_SYMBOL_GPL(inet_unhash); static u32 table_perturb[1 << INET_TABLE_PERTURB_SHIFT]; int __inet_hash_connect(struct inet_timewait_death_row *death_row, - struct sock *sk, u32 port_offset, + struct sock *sk, u64 port_offset, int (*check_established)(struct inet_timewait_death_row *, struct sock *, __u16, struct inet_timewait_sock **)) { @@ -777,7 +777,9 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, net_get_random_once(table_perturb, sizeof(table_perturb)); index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT); - offset = (READ_ONCE(table_perturb[index]) + port_offset) % remaining; + offset = READ_ONCE(table_perturb[index]) + port_offset; + offset %= remaining; + /* In first pass we try ports of @low parity. * inet_csk_get_port() does the opposite choice. */ @@ -859,7 +861,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, int inet_hash_connect(struct inet_timewait_death_row *death_row, struct sock *sk) { - u32 port_offset = 0; + u64 port_offset = 0; if (!inet_sk(sk)->inet_num) port_offset = inet_sk_port_offset(sk); diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index 4740afecf7c6..32ccac10bd62 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -308,7 +308,7 @@ static int __inet6_check_established(struct inet_timewait_death_row *death_row, return -EADDRNOTAVAIL; } -static u32 inet6_sk_port_offset(const struct sock *sk) +static u64 inet6_sk_port_offset(const struct sock *sk) { const struct inet_sock *inet = inet_sk(sk); @@ -320,7 +320,7 @@ static u32 inet6_sk_port_offset(const struct sock *sk) int inet6_hash_connect(struct inet_timewait_death_row *death_row, struct sock *sk) { - u32 port_offset = 0; + u64 port_offset = 0; if (!inet_sk(sk)->inet_num) port_offset = inet6_sk_port_offset(sk); From patchwork Thu Apr 28 12:39:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Willy Tarreau X-Patchwork-Id: 12830625 X-Patchwork-Delegate: kuba@kernel.org 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 9D7D5C433F5 for ; Thu, 28 Apr 2022 12:41:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346482AbiD1MoY (ORCPT ); Thu, 28 Apr 2022 08:44:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346383AbiD1MoX (ORCPT ); Thu, 28 Apr 2022 08:44:23 -0400 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 34579AF1F7; Thu, 28 Apr 2022 05:41:06 -0700 (PDT) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 23SCeFeQ007481; Thu, 28 Apr 2022 14:40:15 +0200 From: Willy Tarreau To: netdev@vger.kernel.org Cc: David Miller , Jakub Kicinski , Eric Dumazet , Moshe Kol , Yossi Gilad , Amit Klein , "Jason A . Donenfeld" , linux-kernel@vger.kernel.org, Willy Tarreau Subject: [PATCH v2 net 2/7] tcp: use different parts of the port_offset for index and offset Date: Thu, 28 Apr 2022 14:39:56 +0200 Message-Id: <20220428124001.7428-3-w@1wt.eu> X-Mailer: git-send-email 2.17.5 In-Reply-To: <20220428124001.7428-1-w@1wt.eu> References: <20220428124001.7428-1-w@1wt.eu> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Amit Klein suggests that we use different parts of port_offset for the table's index and the port offset so that there is no direct relation between them. Cc: Jason A. Donenfeld Cc: Moshe Kol Cc: Yossi Gilad Cc: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau --- net/ipv4/inet_hashtables.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 9d24d9319f3d..29c701cd8312 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -777,7 +777,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, net_get_random_once(table_perturb, sizeof(table_perturb)); index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT); - offset = READ_ONCE(table_perturb[index]) + port_offset; + offset = READ_ONCE(table_perturb[index]) + (port_offset >> 32); offset %= remaining; /* In first pass we try ports of @low parity. From patchwork Thu Apr 28 12:39:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Willy Tarreau X-Patchwork-Id: 12830622 X-Patchwork-Delegate: kuba@kernel.org 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 6C367C433EF for ; Thu, 28 Apr 2022 12:40:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346437AbiD1MoJ (ORCPT ); Thu, 28 Apr 2022 08:44:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346433AbiD1MoG (ORCPT ); Thu, 28 Apr 2022 08:44:06 -0400 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 0FE896324; Thu, 28 Apr 2022 05:40:50 -0700 (PDT) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 23SCeF1G007482; Thu, 28 Apr 2022 14:40:15 +0200 From: Willy Tarreau To: netdev@vger.kernel.org Cc: David Miller , Jakub Kicinski , Eric Dumazet , Moshe Kol , Yossi Gilad , Amit Klein , "Jason A . Donenfeld" , linux-kernel@vger.kernel.org Subject: [PATCH v2 net 3/7] tcp: resalt the secret every 10 seconds Date: Thu, 28 Apr 2022 14:39:57 +0200 Message-Id: <20220428124001.7428-4-w@1wt.eu> X-Mailer: git-send-email 2.17.5 In-Reply-To: <20220428124001.7428-1-w@1wt.eu> References: <20220428124001.7428-1-w@1wt.eu> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@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 55aa5cc258e3..2c76aab20403 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 @@ u64 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 From patchwork Thu Apr 28 12:39:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Willy Tarreau X-Patchwork-Id: 12830627 X-Patchwork-Delegate: kuba@kernel.org 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 4DECCC433EF for ; Thu, 28 Apr 2022 12:41:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346418AbiD1Mo1 (ORCPT ); Thu, 28 Apr 2022 08:44:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346476AbiD1MoT (ORCPT ); Thu, 28 Apr 2022 08:44:19 -0400 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id A17E414092; Thu, 28 Apr 2022 05:41:04 -0700 (PDT) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 23SCeFwD007483; Thu, 28 Apr 2022 14:40:15 +0200 From: Willy Tarreau To: netdev@vger.kernel.org Cc: David Miller , Jakub Kicinski , Eric Dumazet , Moshe Kol , Yossi Gilad , Amit Klein , "Jason A . Donenfeld" , linux-kernel@vger.kernel.org, Willy Tarreau Subject: [PATCH v2 net 4/7] tcp: add small random increments to the source port Date: Thu, 28 Apr 2022 14:39:58 +0200 Message-Id: <20220428124001.7428-5-w@1wt.eu> X-Mailer: git-send-email 2.17.5 In-Reply-To: <20220428124001.7428-1-w@1wt.eu> References: <20220428124001.7428-1-w@1wt.eu> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Here we're randomly adding between 0 and 7 random increments to the selected source port in order to add some noise in the source port selection that will make the next port less predictable. With the default port range of 32768-60999 this means a worst case reuse scenario of 14116/8=1764 connections between two consecutive uses of the same port, with an average of 14116/4.5=3137. This code was stressed at more than 800000 connections per second to a fixed target with all connections closed by the client using RSTs (worst condition) and only 2 connections failed among 13 billion, despite the hash being reseeded every 10 seconds, indicating a perfectly safe situation. Cc: Moshe Kol Cc: Yossi Gilad Cc: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau --- net/ipv4/inet_hashtables.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 29c701cd8312..63bb4902f018 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -833,11 +833,12 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, return -EADDRNOTAVAIL; ok: - /* If our first attempt found a candidate, skip next candidate - * in 1/16 of cases to add some noise. + /* Here we want to add a little bit of randomness to the next source + * port that will be chosen. We use a max() with a random here so that + * on low contention the randomness is maximal and on high contention + * it may be inexistent. */ - if (!i && !(prandom_u32() % 16)) - i = 2; + i = max_t(int, i, (prandom_u32() & 7) * 2); WRITE_ONCE(table_perturb[index], READ_ONCE(table_perturb[index]) + i + 2); /* Head lock still held and bh's disabled */ From patchwork Thu Apr 28 12:39:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Willy Tarreau X-Patchwork-Id: 12830623 X-Patchwork-Delegate: kuba@kernel.org 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 8AC3BC433F5 for ; Thu, 28 Apr 2022 12:41:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346448AbiD1MoR (ORCPT ); Thu, 28 Apr 2022 08:44:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346453AbiD1MoN (ORCPT ); Thu, 28 Apr 2022 08:44:13 -0400 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id EC2F514092; Thu, 28 Apr 2022 05:40:57 -0700 (PDT) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 23SCeF45007484; Thu, 28 Apr 2022 14:40:15 +0200 From: Willy Tarreau To: netdev@vger.kernel.org Cc: David Miller , Jakub Kicinski , Eric Dumazet , Moshe Kol , Yossi Gilad , Amit Klein , "Jason A . Donenfeld" , linux-kernel@vger.kernel.org, Willy Tarreau Subject: [PATCH v2 net 5/7] tcp: dynamically allocate the perturb table used by source ports Date: Thu, 28 Apr 2022 14:39:59 +0200 Message-Id: <20220428124001.7428-6-w@1wt.eu> X-Mailer: git-send-email 2.17.5 In-Reply-To: <20220428124001.7428-1-w@1wt.eu> References: <20220428124001.7428-1-w@1wt.eu> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org We'll need to further increase the size of this table and it's likely that at some point its size will not be suitable anymore for a static table. Let's allocate it on boot from inet_hashinfo2_init(), which is called from tcp_init(). Cc: Moshe Kol Cc: Yossi Gilad Cc: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau --- net/ipv4/inet_hashtables.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 63bb4902f018..48ca07853068 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -731,7 +731,8 @@ EXPORT_SYMBOL_GPL(inet_unhash); * privacy, this only consumes 1 KB of kernel memory. */ #define INET_TABLE_PERTURB_SHIFT 8 -static u32 table_perturb[1 << INET_TABLE_PERTURB_SHIFT]; +#define INET_TABLE_PERTURB_SIZE (1 << INET_TABLE_PERTURB_SHIFT) +static u32 *table_perturb; int __inet_hash_connect(struct inet_timewait_death_row *death_row, struct sock *sk, u64 port_offset, @@ -774,7 +775,8 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, if (likely(remaining > 1)) remaining &= ~1U; - net_get_random_once(table_perturb, sizeof(table_perturb)); + net_get_random_once(table_perturb, + INET_TABLE_PERTURB_SIZE * sizeof(*table_perturb)); index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT); offset = READ_ONCE(table_perturb[index]) + (port_offset >> 32); @@ -912,6 +914,12 @@ void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name, low_limit, high_limit); init_hashinfo_lhash2(h); + + /* this one is used for source ports of outgoing connections */ + table_perturb = kmalloc_array(INET_TABLE_PERTURB_SIZE, + sizeof(*table_perturb), GFP_KERNEL); + if (!table_perturb) + panic("TCP: failed to alloc table_perturb"); } int inet_hashinfo2_init_mod(struct inet_hashinfo *h) From patchwork Thu Apr 28 12:40:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Willy Tarreau X-Patchwork-Id: 12830626 X-Patchwork-Delegate: kuba@kernel.org 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 016EBC433FE for ; Thu, 28 Apr 2022 12:41:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346405AbiD1MoZ (ORCPT ); Thu, 28 Apr 2022 08:44:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46454 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346478AbiD1MoT (ORCPT ); Thu, 28 Apr 2022 08:44:19 -0400 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E908E1409A; Thu, 28 Apr 2022 05:41:04 -0700 (PDT) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 23SCeF74007485; Thu, 28 Apr 2022 14:40:15 +0200 From: Willy Tarreau To: netdev@vger.kernel.org Cc: David Miller , Jakub Kicinski , Eric Dumazet , Moshe Kol , Yossi Gilad , Amit Klein , "Jason A . Donenfeld" , linux-kernel@vger.kernel.org, Willy Tarreau Subject: [PATCH v2 net 6/7] tcp: increase source port perturb table to 2^16 Date: Thu, 28 Apr 2022 14:40:00 +0200 Message-Id: <20220428124001.7428-7-w@1wt.eu> X-Mailer: git-send-email 2.17.5 In-Reply-To: <20220428124001.7428-1-w@1wt.eu> References: <20220428124001.7428-1-w@1wt.eu> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Moshe Kol, Amit Klein, and Yossi Gilad reported being able to accurately identify a client by forcing it to emit only 40 times more connections than there are entries in the table_perturb[] table. The previous two improvements consisting in resalting the secret every 10s and adding randomness to each port selection only slightly improved the situation, and the current value of 2^8 was too small as it's not very difficult to make a client emit 10k connections in less than 10 seconds. Thus we're increasing the perturb table from 2^8 to 2^16 so that the the same precision now requires 2.6M connections, which is more difficult in this time frame and harder to hide as a background activity. The impact is that the table now uses 256 kB instead of 1 kB, which could mostly affect devices making frequent outgoing connections. However such components usually target a small set of destinations (load balancers, database clients, perf assessment tools), and in practice only a few entries will be visited, like before. A live test at 1 million connections per second showed no performance difference from the previous value. Reported-by: Moshe Kol Reported-by: Yossi Gilad Reported-by: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau --- net/ipv4/inet_hashtables.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 48ca07853068..cc5f66328b47 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -726,11 +726,12 @@ EXPORT_SYMBOL_GPL(inet_unhash); * Note that we use 32bit integers (vs RFC 'short integers') * because 2^16 is not a multiple of num_ephemeral and this * property might be used by clever attacker. - * RFC claims using TABLE_LENGTH=10 buckets gives an improvement, - * we use 256 instead to really give more isolation and - * privacy, this only consumes 1 KB of kernel memory. + * RFC claims using TABLE_LENGTH=10 buckets gives an improvement, though + * attacks were since demonstrated, thus we use 65536 instead to really + * give more isolation and privacy, at the expense of 256kB of kernel + * memory. */ -#define INET_TABLE_PERTURB_SHIFT 8 +#define INET_TABLE_PERTURB_SHIFT 16 #define INET_TABLE_PERTURB_SIZE (1 << INET_TABLE_PERTURB_SHIFT) static u32 *table_perturb; From patchwork Thu Apr 28 12:40:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Willy Tarreau X-Patchwork-Id: 12830628 X-Patchwork-Delegate: kuba@kernel.org 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 43E65C433EF for ; Thu, 28 Apr 2022 12:41:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346580AbiD1Mox (ORCPT ); Thu, 28 Apr 2022 08:44:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346498AbiD1Mom (ORCPT ); Thu, 28 Apr 2022 08:44:42 -0400 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 55502AFAE4; Thu, 28 Apr 2022 05:41:14 -0700 (PDT) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 23SCeFwv007486; Thu, 28 Apr 2022 14:40:15 +0200 From: Willy Tarreau To: netdev@vger.kernel.org Cc: David Miller , Jakub Kicinski , Eric Dumazet , Moshe Kol , Yossi Gilad , Amit Klein , "Jason A . Donenfeld" , linux-kernel@vger.kernel.org, Willy Tarreau Subject: [PATCH v2 net 7/7] tcp: drop the hash_32() part from the index calculation Date: Thu, 28 Apr 2022 14:40:01 +0200 Message-Id: <20220428124001.7428-8-w@1wt.eu> X-Mailer: git-send-email 2.17.5 In-Reply-To: <20220428124001.7428-1-w@1wt.eu> References: <20220428124001.7428-1-w@1wt.eu> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org In commit 190cc82489f4 ("tcp: change source port randomizarion at connect() time"), the table_perturb[] array was introduced and an index was taken from the port_offset via hash_32(). But it turns out that hash_32() performs a multiplication while the input here comes from the output of SipHash in secure_seq, that is well distributed enough to avoid the need for yet another hash. Suggested-by: Amit Klein Reviewed-by: Eric Dumazet Signed-off-by: Willy Tarreau --- net/ipv4/inet_hashtables.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index cc5f66328b47..a5d57fa679ca 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -778,7 +778,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row, net_get_random_once(table_perturb, INET_TABLE_PERTURB_SIZE * sizeof(*table_perturb)); - index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT); + index = port_offset & (INET_TABLE_PERTURB_SIZE - 1); offset = READ_ONCE(table_perturb[index]) + (port_offset >> 32); offset %= remaining;