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=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 6EBA2C43603 for ; Thu, 19 Dec 2019 19:03:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 430FC2465E for ; Thu, 19 Dec 2019 19:03:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576782188; bh=vnlyVA6cwn8a4mK17bHZcZzqJtKoVj/dJH//7UygEPQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MUpZ6dQV0mR6lTb8EshIneFI1HgywNMtNSNX4O4ahqaAJCgz0jRty7UDHwqZC0frd xb70GXzflkm6Lr+hyxN4reXzUDKA984eALzBJ6NCNY7KMOSVO+M2yccklS1+QGmT1A NvqXyI1SfhYGWdsAEMRWbbG2Cw336cIky8YVSohc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727680AbfLSTDH (ORCPT ); Thu, 19 Dec 2019 14:03:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:41958 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729296AbfLSSsq (ORCPT ); Thu, 19 Dec 2019 13:48:46 -0500 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 DE49324679; Thu, 19 Dec 2019 18:48:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576781325; bh=vnlyVA6cwn8a4mK17bHZcZzqJtKoVj/dJH//7UygEPQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ub3+Xcp8m5jBE8Cq556akESvFBhsvKjzauTIjImPiFS+/D0nf6PIhagKHd4d8QjI8 NaIc6f7qRuVqSEMhR0IBODObCtyGjU3tDRmu0sjog10LxVPZ//cmxHQY81JDxS72eU cDA6+/s7o+CJjixy184jITmnfVJFja5SrTs1dXHw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+2add91c08eb181fea1bf@syzkaller.appspotmail.com, Nikolay Aleksandrov , "David S. Miller" Subject: [PATCH 4.9 176/199] net: bridge: deny dev_set_mac_address() when unregistering Date: Thu, 19 Dec 2019 19:34:18 +0100 Message-Id: <20191219183225.312964208@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191219183214.629503389@linuxfoundation.org> References: <20191219183214.629503389@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: Nikolay Aleksandrov [ Upstream commit c4b4c421857dc7b1cf0dccbd738472360ff2cd70 ] We have an interesting memory leak in the bridge when it is being unregistered and is a slave to a master device which would change the mac of its slaves on unregister (e.g. bond, team). This is a very unusual setup but we do end up leaking 1 fdb entry because dev_set_mac_address() would cause the bridge to insert the new mac address into its table after all fdbs are flushed, i.e. after dellink() on the bridge has finished and we call NETDEV_UNREGISTER the bond/team would release it and will call dev_set_mac_address() to restore its original address and that in turn will add an fdb in the bridge. One fix is to check for the bridge dev's reg_state in its ndo_set_mac_address callback and return an error if the bridge is not in NETREG_REGISTERED. Easy steps to reproduce: 1. add bond in mode != A/B 2. add any slave to the bond 3. add bridge dev as a slave to the bond 4. destroy the bridge device Trace: unreferenced object 0xffff888035c4d080 (size 128): comm "ip", pid 4068, jiffies 4296209429 (age 1413.753s) hex dump (first 32 bytes): 41 1d c9 36 80 88 ff ff 00 00 00 00 00 00 00 00 A..6............ d2 19 c9 5e 3f d7 00 00 00 00 00 00 00 00 00 00 ...^?........... backtrace: [<00000000ddb525dc>] kmem_cache_alloc+0x155/0x26f [<00000000633ff1e0>] fdb_create+0x21/0x486 [bridge] [<0000000092b17e9c>] fdb_insert+0x91/0xdc [bridge] [<00000000f2a0f0ff>] br_fdb_change_mac_address+0xb3/0x175 [bridge] [<000000001de02dbd>] br_stp_change_bridge_id+0xf/0xff [bridge] [<00000000ac0e32b1>] br_set_mac_address+0x76/0x99 [bridge] [<000000006846a77f>] dev_set_mac_address+0x63/0x9b [<00000000d30738fc>] __bond_release_one+0x3f6/0x455 [bonding] [<00000000fc7ec01d>] bond_netdev_event+0x2f2/0x400 [bonding] [<00000000305d7795>] notifier_call_chain+0x38/0x56 [<0000000028885d4a>] call_netdevice_notifiers+0x1e/0x23 [<000000008279477b>] rollback_registered_many+0x353/0x6a4 [<0000000018ef753a>] unregister_netdevice_many+0x17/0x6f [<00000000ba854b7a>] rtnl_delete_link+0x3c/0x43 [<00000000adf8618d>] rtnl_dellink+0x1dc/0x20a [<000000009b6395fd>] rtnetlink_rcv_msg+0x23d/0x268 Fixes: 43598813386f ("bridge: add local MAC address to forwarding table (v2)") Reported-by: syzbot+2add91c08eb181fea1bf@syzkaller.appspotmail.com Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/bridge/br_device.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/net/bridge/br_device.c +++ b/net/bridge/br_device.c @@ -210,6 +210,12 @@ static int br_set_mac_address(struct net if (!is_valid_ether_addr(addr->sa_data)) return -EADDRNOTAVAIL; + /* dev_set_mac_addr() can be called by a master device on bridge's + * NETDEV_UNREGISTER, but since it's being destroyed do nothing + */ + if (dev->reg_state != NETREG_REGISTERED) + return -EBUSY; + spin_lock_bh(&br->lock); if (!ether_addr_equal(dev->dev_addr, addr->sa_data)) { /* Mac address will be changed in br_stp_change_bridge_id(). */