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 D7506C433E0 for ; Mon, 18 May 2020 17:41:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A98E920657 for ; Mon, 18 May 2020 17:41:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589823660; bh=YNrWYBeTxYdb0O+DbcPxCij4hDjcu6RrXCU7kSPbevw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OlBFahb9EgjS4Y5iRa2FTVxx2khV96Y6vjC2x5NFiDyvL3samCDthQzU3qB/Q7s+Y M+If2E39QmAZdd1CjSE/MeamrG2JfaTiZ7KSkxrH/a8/gYypCwLPzE50GL4kil9flS 2PN5dZRaWbTiNewzW9DMw321PakJod4iyDBQysio= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729191AbgERRk6 (ORCPT ); Mon, 18 May 2020 13:40:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:37056 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728547AbgERRk5 (ORCPT ); Mon, 18 May 2020 13:40:57 -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 1ED2520657; Mon, 18 May 2020 17:40:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589823657; bh=YNrWYBeTxYdb0O+DbcPxCij4hDjcu6RrXCU7kSPbevw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XArpVYw1UUGEX0OXRCNPFAJV/0SOriWcfHweIhBnJq45AwAiukg3T7ZUxDtj+ikWU aswbBRk07MOVvxMrkhIlhx5Cr2HCPhqrryX9F5H6v3MMPfdf35fNo2Ck95j0Uz53JX zt0NPx5f/utQ0EyDqWGf3GfbVu52to8LXwIxbZ/A= 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 4.4 70/86] net: ipv4: really enforce backoff for redirects Date: Mon, 18 May 2020 19:36:41 +0200 Message-Id: <20200518173504.516498385@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518173450.254571947@linuxfoundation.org> References: <20200518173450.254571947@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 @@ -898,7 +898,7 @@ 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)))) {