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 D8A11C43331 for ; Wed, 1 Apr 2020 16:23:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E465214D8 for ; Wed, 1 Apr 2020 16:23:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585758207; bh=Hjo/1PqEYyDhif3+DpF6CPXHbPIGc7cBS7EnSzDdDEY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aChy+XLHYF5VfbVfYfrZ4O1r4ZfqBFTnbRyAhHAaEOXxk7WCOmcpcw3/xfjcyBFmW z1kY1mxd7EsBAr+Op/E3MGZIGJYxod75dNXJgPNkp7/xQ2OX/9wVV1NWYxHW4WUUn7 ybTNQYDjx/AuWw6YRqpwnuV3YDpwloM7QuOPti0E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387588AbgDAQX0 (ORCPT ); Wed, 1 Apr 2020 12:23:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:46650 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387579AbgDAQXW (ORCPT ); Wed, 1 Apr 2020 12:23:22 -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 B24352137B; Wed, 1 Apr 2020 16:23:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585758202; bh=Hjo/1PqEYyDhif3+DpF6CPXHbPIGc7cBS7EnSzDdDEY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ttoi3bW8AUv1+9anCthDU8au0PCK4/DOV4N5A6pvnwodyBP4XwiiSgXqGEUhE/QAm B7JnGHfY/aDpEj8LTh0CqrBs6XxWb2Sqg9sbztHEoq5rNzl7xx/7e2M1W8TIr7S2Fg v1IbjFe8I79AvnjX0qyAuiRomK2YPSvPWYM3e+PY= 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 4.19 016/116] net_sched: cls_route: remove the right filter from hashtable Date: Wed, 1 Apr 2020 18:16:32 +0200 Message-Id: <20200401161544.169172781@linuxfoundation.org> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200401161542.669484650@linuxfoundation.org> References: <20200401161542.669484650@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 @@ -536,8 +536,8 @@ 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; } }