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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 46A04C433DF for ; Thu, 28 May 2020 12:09:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2404221548 for ; Thu, 28 May 2020 12:09:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590667777; bh=A4ErLDkg+iKuLu7wJxcdIY1HcKsBkp1TkTpfBywLic0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=swF1bR2th5IZbW6oJwObQZ32TuQc5D7OoqZnslWjzZGN+3iFZyTV8fhWNrnIX5ery HIikLoo3Vhs3M7grDtn4Wy2n0ycFdg1pPuCNpIC+ez+YNtlcFmXZhWqKOKPCYlT0D4 0R/OFHd1g5Pj4ejnqYug738Dqi7LoEIwegiZBoG8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389620AbgE1MJf (ORCPT ); Thu, 28 May 2020 08:09:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:48584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388650AbgE1L43 (ORCPT ); Thu, 28 May 2020 07:56:29 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7E05B21531; Thu, 28 May 2020 11:56:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590666988; bh=A4ErLDkg+iKuLu7wJxcdIY1HcKsBkp1TkTpfBywLic0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=01dNRwsBZ5i1yGch5KcM8AlwBumqDGtAVwOpDBW+Wgwl6EKdNcZRIkeN0qRaYrc5B H8/f68+9IcvWpCHFpBGQ3gEpbh024oXXhKG4+qtd9aYv3iQN/kDN299hnysXLxxqLl HhpOufbqgcyOFh39axpq/KCaTlAwo36Cs74eD7RM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Jason A. Donenfeld" , Dave Taht , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.6 24/47] wireguard: queueing: preserve flow hash across packet scrubbing Date: Thu, 28 May 2020 07:55:37 -0400 Message-Id: <20200528115600.1405808-24-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200528115600.1405808-1-sashal@kernel.org> References: <20200528115600.1405808-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Jason A. Donenfeld" [ Upstream commit c78a0b4a78839d572d8a80f6a62221c0d7843135 ] It's important that we clear most header fields during encapsulation and decapsulation, because the packet is substantially changed, and we don't want any info leak or logic bug due to an accidental correlation. But, for encapsulation, it's wrong to clear skb->hash, since it's used by fq_codel and flow dissection in general. Without it, classification does not proceed as usual. This change might make it easier to estimate the number of innerflows by examining clustering of out of order packets, but this shouldn't open up anything that can't already be inferred otherwise (e.g. syn packet size inference), and fq_codel can be disabled anyway. Furthermore, it might be the case that the hash isn't used or queried at all until after wireguard transmits the encrypted UDP packet, which means skb->hash might still be zero at this point, and thus no hash taken over the inner packet data. In order to address this situation, we force a calculation of skb->hash before encrypting packet data. Of course this means that fq_codel might transmit packets slightly more out of order than usual. Toke did some testing on beefy machines with high quantities of parallel flows and found that increasing the reply-attack counter to 8192 takes care of the most pathological cases pretty well. Reported-by: Dave Taht Reviewed-and-tested-by: Toke Høiland-Jørgensen Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") Signed-off-by: Jason A. Donenfeld Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/wireguard/messages.h | 2 +- drivers/net/wireguard/queueing.h | 10 +++++++++- drivers/net/wireguard/receive.c | 2 +- drivers/net/wireguard/send.c | 7 ++++++- 4 files changed, 17 insertions(+), 4 deletions(-) diff --git a/drivers/net/wireguard/messages.h b/drivers/net/wireguard/messages.h index b8a7b9ce32ba..208da72673fc 100644 --- a/drivers/net/wireguard/messages.h +++ b/drivers/net/wireguard/messages.h @@ -32,7 +32,7 @@ enum cookie_values { }; enum counter_values { - COUNTER_BITS_TOTAL = 2048, + COUNTER_BITS_TOTAL = 8192, COUNTER_REDUNDANT_BITS = BITS_PER_LONG, COUNTER_WINDOW_SIZE = COUNTER_BITS_TOTAL - COUNTER_REDUNDANT_BITS }; diff --git a/drivers/net/wireguard/queueing.h b/drivers/net/wireguard/queueing.h index 3432232afe06..c58df439dbbe 100644 --- a/drivers/net/wireguard/queueing.h +++ b/drivers/net/wireguard/queueing.h @@ -87,12 +87,20 @@ static inline bool wg_check_packet_protocol(struct sk_buff *skb) return real_protocol && skb->protocol == real_protocol; } -static inline void wg_reset_packet(struct sk_buff *skb) +static inline void wg_reset_packet(struct sk_buff *skb, bool encapsulating) { + u8 l4_hash = skb->l4_hash; + u8 sw_hash = skb->sw_hash; + u32 hash = skb->hash; skb_scrub_packet(skb, true); memset(&skb->headers_start, 0, offsetof(struct sk_buff, headers_end) - offsetof(struct sk_buff, headers_start)); + if (encapsulating) { + skb->l4_hash = l4_hash; + skb->sw_hash = sw_hash; + skb->hash = hash; + } skb->queue_mapping = 0; skb->nohdr = 0; skb->peeked = 0; diff --git a/drivers/net/wireguard/receive.c b/drivers/net/wireguard/receive.c index 2566e13a292d..758d6a019184 100644 --- a/drivers/net/wireguard/receive.c +++ b/drivers/net/wireguard/receive.c @@ -485,7 +485,7 @@ int wg_packet_rx_poll(struct napi_struct *napi, int budget) if (unlikely(wg_socket_endpoint_from_skb(&endpoint, skb))) goto next; - wg_reset_packet(skb); + wg_reset_packet(skb, false); wg_packet_consume_data_done(peer, skb, &endpoint); free = false; diff --git a/drivers/net/wireguard/send.c b/drivers/net/wireguard/send.c index e8a7d0a0cb88..0d64a7531f64 100644 --- a/drivers/net/wireguard/send.c +++ b/drivers/net/wireguard/send.c @@ -170,6 +170,11 @@ static bool encrypt_packet(struct sk_buff *skb, struct noise_keypair *keypair) struct sk_buff *trailer; int num_frags; + /* Force hash calculation before encryption so that flow analysis is + * consistent over the inner packet. + */ + skb_get_hash(skb); + /* Calculate lengths. */ padding_len = calculate_skb_padding(skb); trailer_len = padding_len + noise_encrypted_len(0); @@ -298,7 +303,7 @@ void wg_packet_encrypt_worker(struct work_struct *work) skb_list_walk_safe(first, skb, next) { if (likely(encrypt_packet(skb, PACKET_CB(first)->keypair))) { - wg_reset_packet(skb); + wg_reset_packet(skb, true); } else { state = PACKET_STATE_DEAD; break; -- 2.25.1