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,URIBL_BLOCKED,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 7687EC7618B for ; Fri, 26 Jul 2019 15:39:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F7B4205F4 for ; Fri, 26 Jul 2019 15:39:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564155546; bh=V7+Br9o9LhsUH2f7E9v51PJEkEZe8FFACI/PZu6wLkU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=frUNLKSgQF9tacWoTAP5gySsS8NSTDnTLdHaUrdGarj2SpgmZHNDO3h3kMbBL+BUC HjuAtWdprADN4cM8NrekDG0+7uXmCRJGo37/9OOnaQjof7C7yF1QDxQ0i0zXnjlceV X1fSlERlRMdoOrC5Bcm0JFpJ859ZvANVjC5ND1ts= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388832AbfGZPjF (ORCPT ); Fri, 26 Jul 2019 11:39:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:40986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388135AbfGZP0z (ORCPT ); Fri, 26 Jul 2019 11:26:55 -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 F271322BF5; Fri, 26 Jul 2019 15:26:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564154814; bh=V7+Br9o9LhsUH2f7E9v51PJEkEZe8FFACI/PZu6wLkU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CGuDKjbayr8TVcJZOF4Lzvr+GfB4hufSdPc/KkcYUonHVkKZ3UnEVaI6wpXomKWNf nqu0sQdJ7iam5FY9nTM6Sdc3ps1VcoGcBDmXhkJCT0YLhznkIiNqKg3V38lt3HFAZY HxzktTrQxHloWGevLEzN4U3UXlmhW7wlefOEASJw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ido Schimmel , Alexander Petrovskiy , David Ahern , "David S. Miller" Subject: [PATCH 5.2 07/66] ipv6: Unlink sibling route in case of failure Date: Fri, 26 Jul 2019 17:24:06 +0200 Message-Id: <20190726152302.707755084@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190726152301.936055394@linuxfoundation.org> References: <20190726152301.936055394@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: Ido Schimmel [ Upstream commit 54851aa90cf27041d64b12f65ac72e9f97bd90fd ] When a route needs to be appended to an existing multipath route, fib6_add_rt2node() first appends it to the siblings list and increments the number of sibling routes on each sibling. Later, the function notifies the route via call_fib6_entry_notifiers(). In case the notification is vetoed, the route is not unlinked from the siblings list, which can result in a use-after-free. Fix this by unlinking the route from the siblings list before returning an error. Audited the rest of the call sites from which the FIB notification chain is called and could not find more problems. Fixes: 2233000cba40 ("net/ipv6: Move call_fib6_entry_notifiers up for route adds") Signed-off-by: Ido Schimmel Reported-by: Alexander Petrovskiy Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_fib.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -1104,8 +1104,24 @@ add: err = call_fib6_entry_notifiers(info->nl_net, FIB_EVENT_ENTRY_ADD, rt, extack); - if (err) + if (err) { + struct fib6_info *sibling, *next_sibling; + + /* If the route has siblings, then it first + * needs to be unlinked from them. + */ + if (!rt->fib6_nsiblings) + return err; + + list_for_each_entry_safe(sibling, next_sibling, + &rt->fib6_siblings, + fib6_siblings) + sibling->fib6_nsiblings--; + rt->fib6_nsiblings = 0; + list_del_init(&rt->fib6_siblings); + rt6_multipath_rebalance(next_sibling); return err; + } rcu_assign_pointer(rt->fib6_next, iter); fib6_info_hold(rt);