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 lists.zx2c4.com (lists.zx2c4.com [165.227.139.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 44A7CC64EC4 for ; Sun, 19 Feb 2023 17:03:06 +0000 (UTC) Received: by lists.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 28f5abe1; Sun, 19 Feb 2023 17:03:05 +0000 (UTC) Received: from mail.as41281.net (mail.as41281.net [2a0f:df00:0:300::109]) by lists.zx2c4.com (ZX2C4 Mail Server) with ESMTPS id b8379df1 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO) for ; Sun, 19 Feb 2023 16:54:31 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id ABF90161AAD for ; Sun, 19 Feb 2023 17:54:29 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=keff.org; s=dkim; t=1676825670; h=from:subject:date:message-id:to:mime-version:content-type: content-transfer-encoding:content-language:in-reply-to:references; bh=P7dyiCeg1soKSo1FBukZpXucfKX2T69MAJgBCWLHNNs=; b=D/ApZIAelAE2R7mvbgdLNp1iZb1R1ec1pCEaqIj491u4qE04tgkNIajP5js+kbq2C1aja6 sdwSRm9h/1MLSTzHPv8Dmcbl1mkjRgnN/XNEwKtbz4xguHSKKakk3bfXHF1CYIsdtldX73 RpE0fuo339oXVo3XcEUhm57pNCDpgTk= Message-ID: <00b94fdf-22d5-00ad-e068-30ad4a453236@keff.org> Date: Sun, 19 Feb 2023 23:54:10 +0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:110.0) Gecko/20100101 Thunderbird/110.0 Subject: Re: Source IP incorrect on multi homed systems Content-Language: en-US To: wireguard@lists.zx2c4.com References: <875yby83n2.fsf@ungleich.ch> <2ed829aaed9fec59ac2a9b32c4ce0a9005b8d8b850be81c81a226791855fe4eb@mu.id> <87ttzhc0jt.fsf@ungleich.ch> <7d7bc930-65d9-f13e-cedc-e0451407be85@chil.at> From: Sebastian Hyrvall In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Last-TLS-Session-Version: TLSv1.3 X-Mailman-Approved-At: Sun, 19 Feb 2023 17:02:58 +0000 X-BeenThere: wireguard@lists.zx2c4.com X-Mailman-Version: 2.1.30rc1 Precedence: list List-Id: Development discussion of WireGuard List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: wireguard-bounces@lists.zx2c4.com Sender: "WireGuard" You should get into that debate. Proposing firewall workarounds is not a correct solution so please don't do it. It needs to be fixed. It's an immature VPN solution that always just proposed a workaround instead of fixing the problem. It seems to be designed by people that are good at software and cryptography but has no clue about networking stacks. On 2023-02-19 23:32, David Kerr wrote: > Without getting into the debate of whether wireguard is acting > correctly or not, I think there is a possible workaround. > > 1. In the iptables mangle table PREROUTING, match the incoming > interface and destination address and --set-xmark a firewall MARK > unique to this interface/destination > 2. Create a new ip route table that sets the default route to go out > on the interface with the source address you want (same as destination > address in iptables) > 3. Create a new ip rule that sends all packets with firewall mark set > in iptables to the routing table you just created > > Repeat above for each interface/address you need to mangle, with a > unique firewall mark and routing table for each. > > It may be necessary to use CONNMARK in PREROUTING and OUTPUT to > --restore_mark. I can't remember if this is needed or not, its been a > while since I configured iptables with this. > > This should ensure that any packet that comes into an > interface/address is replied to from the same interface/address. > > David > > > On Sun, Feb 19, 2023 at 9:44 AM Christoph Loesch wrote: >> Hi, >> >> I don't think no one wants to fix it, there are several users having this issue. I rather guess no one could find a suitable solution to fix it. >> >> @Nico: did you try to delete the affected route and add it again with the correct source IP ? >> >> as I mentioned it in https://lists.zx2c4.com/pipermail/wireguard/2021-November/007324.html >> >> ip route del >> ip route add dev src >> >> This way I was able to (at least temporary) fix this issue on multi homed systems. >> >> Kind regards, >> Christoph >> >> Am 19.02.2023 um 13:13 schrieb Nico Schottelius: >>> Hey Sebastian, >>> >>> Sebastian Hyrwall writes: >>> >>>> It is kinda. It's been mentioned multiple times over the years but no one seems to want to fix it. Atleast you should be able to specify bind/src ip in the >>>> config. I gave up WG because of it. Wasn't accepted by my projects security policy since src ip could not be configured. >>>> >>>> There is an unofficial patch however, >>>> >>>> https://github.com/torvalds/linux/commit/5fa98082093344c86345f9f63305cae9d5f9f281 >>> the binding is somewhat related to this issue and I was looking for that >>> feature some time ago, too. While it is correlated and I would really >>> appreciate binding support, I am not sure whether the linked patch does >>> actually fix the problem I am seeing in multi homed devices. >>> >>> As long as wireguard does not reply with the same IP address it was >>> contacted with, packets will get dropped on stateful firewalls, because >>> the returning packet does not match the state session database. >>> >>> Best regards, >>> >>> Nico >>> >>> -- >>> Sustainable and modern Infrastructures by ungleich.ch