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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 7BAF1C433E2 for ; Mon, 18 May 2020 17:49:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4545220715 for ; Mon, 18 May 2020 17:49:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589824144; bh=mtin70/tczYBldlX8vAJG1SyEuIs8VXY9/Z6HZC1mKM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=te3xjmpfOV4rfxQ9GExFvcrbPGttuIS0nu1xrWSl5gh3tTfqNWEQho6r2H5aMon13 nKu/absUdgXqY/9sV5qc3ZRDigyMzewwn4fvI5ErMiNUDDGXx8mG+l+I+EoSkyzy9z ZxNGEvlb10FoXRRR9y278qsSGGx0T+tgogmFngiQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730473AbgERRtD (ORCPT ); Mon, 18 May 2020 13:49:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:50170 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730456AbgERRs6 (ORCPT ); Mon, 18 May 2020 13:48:58 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E628020657; Mon, 18 May 2020 17:48:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589824137; bh=mtin70/tczYBldlX8vAJG1SyEuIs8VXY9/Z6HZC1mKM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d7AOjl1XRW4rgqJLFZO9uWjiTmXdx0RHWKPQf9Sr6r83Wlrhig6LQXSvYBUAkVwDc Is35E72QYH9DW/I6Zg8uh5A7DFincALBTiJm9ePWJwtSdeTsDKh3KHbLxHS8jytDAU 68sdQgc9WFIY6jotUuitCiij1npR6wiNeJpTwVf0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paolo Abeni , Jakub Kicinski , Colin Walters Subject: [PATCH 4.14 087/114] net: ipv4: really enforce backoff for redirects Date: Mon, 18 May 2020 19:36:59 +0200 Message-Id: <20200518173518.183640004@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518173503.033975649@linuxfoundation.org> References: <20200518173503.033975649@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paolo Abeni [ Upstream commit 57644431a6c2faac5d754ebd35780cf43a531b1a ] In commit b406472b5ad7 ("net: ipv4: avoid mixed n_redirects and rate_tokens usage") I missed the fact that a 0 'rate_tokens' will bypass the backoff algorithm. Since rate_tokens is cleared after a redirect silence, and never incremented on redirects, if the host keeps receiving packets requiring redirect it will reply ignoring the backoff. Additionally, the 'rate_last' field will be updated with the cadence of the ingress packet requiring redirect. If that rate is high enough, that will prevent the host from generating any other kind of ICMP messages The check for a zero 'rate_tokens' value was likely a shortcut to avoid the more complex backoff algorithm after a redirect silence period. Address the issue checking for 'n_redirects' instead, which is incremented on successful redirect, and does not interfere with other ICMP replies. Fixes: b406472b5ad7 ("net: ipv4: avoid mixed n_redirects and rate_tokens usage") Reported-and-tested-by: Colin Walters Signed-off-by: Paolo Abeni Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/ipv4/route.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -921,7 +921,7 @@ void ip_rt_send_redirect(struct sk_buff /* Check for load limit; set rate_last to the latest sent * redirect. */ - if (peer->rate_tokens == 0 || + if (peer->n_redirects == 0 || time_after(jiffies, (peer->rate_last + (ip_rt_redirect_load << peer->n_redirects)))) {