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=-6.9 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 CFD55C43331 for ; Tue, 31 Mar 2020 09:14:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A2743206F6 for ; Tue, 31 Mar 2020 09:14:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585646050; bh=S092gFVFtOYE7P8NHrfnFQpRTJsmjesAJzX7X3rp8K8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ke4JX4+P4HY4w0DAMyCgbUHkL1AUCfHBSpmyZLpIY9InRwZdhb5+sFYayht93sn3N uLkXUAiZ3KQzfk+6xsrLmS64do2DHN+8pNNzwITG6qdb0aQqEniY2lgqTcqxk36uof pQHwzTJN9tJ0Yi+VWWBWktuAUCcyWo5ZjhPfqdC8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731812AbgCaJOI (ORCPT ); Tue, 31 Mar 2020 05:14:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:33842 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731796AbgCaJOG (ORCPT ); Tue, 31 Mar 2020 05:14:06 -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 1BA852145D; Tue, 31 Mar 2020 09:14:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585646045; bh=S092gFVFtOYE7P8NHrfnFQpRTJsmjesAJzX7X3rp8K8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oYDC90zS+6P0C0nG1LwvAI1feSo2DOVVcYe1LQpbLseulF/8uMsXQPxSdBNJ4QtI5 Q99roJvpDQcHQY8YLkmfdBlOXZFnviI3bkhC5kQFer4sEoYqnae/tY+kzSAyCKS9MK qydAeOYCeYESd/BuH9b1qG3Nv/apPSguUaIIZmDs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jamal Hadi Salim , Jiri Pirko , John Fastabend , Cong Wang , "David S. Miller" , syzbot+f9b32aaacd60305d9687@syzkaller.appspotmail.com, syzbot+2f8c233f131943d6056d@syzkaller.appspotmail.com, syzbot+9c2df9fd5e9445b74e01@syzkaller.appspotmail.com Subject: [PATCH 5.4 028/155] net_sched: cls_route: remove the right filter from hashtable Date: Tue, 31 Mar 2020 10:57:48 +0200 Message-Id: <20200331085421.551530550@linuxfoundation.org> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200331085418.274292403@linuxfoundation.org> References: <20200331085418.274292403@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: Cong Wang [ Upstream commit ef299cc3fa1a9e1288665a9fdc8bff55629fd359 ] route4_change() allocates a new filter and copies values from the old one. After the new filter is inserted into the hash table, the old filter should be removed and freed, as the final step of the update. However, the current code mistakenly removes the new one. This looks apparently wrong to me, and it causes double "free" and use-after-free too, as reported by syzbot. Reported-and-tested-by: syzbot+f9b32aaacd60305d9687@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+2f8c233f131943d6056d@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+9c2df9fd5e9445b74e01@syzkaller.appspotmail.com Fixes: 1109c00547fc ("net: sched: RCU cls_route") Cc: Jamal Hadi Salim Cc: Jiri Pirko Cc: John Fastabend Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/cls_route.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/sched/cls_route.c +++ b/net/sched/cls_route.c @@ -534,8 +534,8 @@ static int route4_change(struct net *net fp = &b->ht[h]; for (pfp = rtnl_dereference(*fp); pfp; fp = &pfp->next, pfp = rtnl_dereference(*fp)) { - if (pfp == f) { - *fp = f->next; + if (pfp == fold) { + rcu_assign_pointer(*fp, fold->next); break; } }