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=-6.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 084B0C00319 for ; Thu, 21 Feb 2019 14:51:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD1F22075A for ; Thu, 21 Feb 2019 14:51:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550760693; bh=EZyf0wrWWPOALuN2FgWUTJc+HlVlx8IW7VJxivzubEs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QZqR1kvc0I0loEglXHnd9jzxHiA37zxFsMRDR9yagklqiSVdhGTx01QbC8FGbvydF FeuiSlMfA2YUubWcum4eQDs2613RezQfCndyRq+FXXu73T26fgL9hZ/LDo/htv7De0 6pDleJQAXjQJ1TeqxMIVkEEgEOx2IRNsSGhEYDZg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728291AbfBUOhO (ORCPT ); Thu, 21 Feb 2019 09:37:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:58288 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727594AbfBUOhN (ORCPT ); Thu, 21 Feb 2019 09:37:13 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 39E312075C; Thu, 21 Feb 2019 14:37:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550759832; bh=EZyf0wrWWPOALuN2FgWUTJc+HlVlx8IW7VJxivzubEs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L65ybsFnryQnWfXBsT8XecXt+VaNRwr76oaukRCUEvuTW55rhAsdgOHvDuJd3PPw2 lBAOXTZ++i1hGpsadZ+oHV7A031UFOszof5WxZW7penUeR0spaeuu//7lhGusyE8TA bvL5PTHB/cu8+MjyLJXbLDvGC9Em+uwO4smxe8ik= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lorenzo Bianconi , "David S. Miller" Subject: [PATCH 3.18 08/13] net: ipv4: use a dedicated counter for icmp_v4 redirect packets Date: Thu, 21 Feb 2019 15:35:39 +0100 Message-Id: <20190221125240.937496983@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190221125240.091472334@linuxfoundation.org> References: <20190221125240.091472334@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lorenzo Bianconi [ Upstream commit c09551c6ff7fe16a79a42133bcecba5fc2fc3291 ] According to the algorithm described in the comment block at the beginning of ip_rt_send_redirect, the host should try to send 'ip_rt_redirect_number' ICMP redirect packets with an exponential backoff and then stop sending them at all assuming that the destination ignores redirects. If the device has previously sent some ICMP error packets that are rate-limited (e.g TTL expired) and continues to receive traffic, the redirect packets will never be transmitted. This happens since peer->rate_tokens will be typically greater than 'ip_rt_redirect_number' and so it will never be reset even if the redirect silence timeout (ip_rt_redirect_silence) has elapsed without receiving any packet requiring redirects. Fix it by using a dedicated counter for the number of ICMP redirect packets that has been sent by the host I have not been able to identify a given commit that introduced the issue since ip_rt_send_redirect implements the same rate-limiting algorithm from commit 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Lorenzo Bianconi Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/net/inetpeer.h | 1 + net/ipv4/inetpeer.c | 1 + net/ipv4/route.c | 7 +++++-- 3 files changed, 7 insertions(+), 2 deletions(-) --- a/include/net/inetpeer.h +++ b/include/net/inetpeer.h @@ -35,6 +35,7 @@ struct inet_peer { u32 metrics[RTAX_MAX]; u32 rate_tokens; /* rate limiting for ICMP */ + u32 n_redirects; unsigned long rate_last; union { struct list_head gc_list; --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -464,6 +464,7 @@ relookup: atomic_set(&p->rid, 0); p->metrics[RTAX_LOCK-1] = INETPEER_METRICS_NEW; p->rate_tokens = 0; + p->n_redirects = 0; /* 60*HZ is arbitrary, but chosen enough high so that the first * calculation of tokens is at its maximum. */ --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -864,13 +864,15 @@ void ip_rt_send_redirect(struct sk_buff /* No redirected packets during ip_rt_redirect_silence; * reset the algorithm. */ - if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) + if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence)) { peer->rate_tokens = 0; + peer->n_redirects = 0; + } /* Too many ignored redirects; do not send anything * set dst.rate_last to the last seen redirected packet. */ - if (peer->rate_tokens >= ip_rt_redirect_number) { + if (peer->n_redirects >= ip_rt_redirect_number) { peer->rate_last = jiffies; goto out_put_peer; } @@ -887,6 +889,7 @@ void ip_rt_send_redirect(struct sk_buff icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw); peer->rate_last = jiffies; ++peer->rate_tokens; + ++peer->n_redirects; #ifdef CONFIG_IP_ROUTE_VERBOSE if (log_martians && peer->rate_tokens == ip_rt_redirect_number)