From patchwork Thu Mar 14 05:47:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yue Haibing X-Patchwork-Id: 1056344 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=huawei.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44Kd6q20Cmz9s70 for ; Thu, 14 Mar 2019 16:48:35 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727241AbfCNFsa (ORCPT ); Thu, 14 Mar 2019 01:48:30 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:48930 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726303AbfCNFsa (ORCPT ); Thu, 14 Mar 2019 01:48:30 -0400 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 28900EB1611D2922C173; Thu, 14 Mar 2019 13:48:28 +0800 (CST) Received: from localhost (10.177.31.96) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.408.0; Thu, 14 Mar 2019 13:48:19 +0800 From: Yue Haibing To: , , CC: , , YueHaibing Subject: [PATCH v2] appletalk: Fix potential NULL pointer dereference in unregister_snap_client Date: Thu, 14 Mar 2019 13:47:59 +0800 Message-ID: <20190314054759.17848-1-yuehaibing@huawei.com> X-Mailer: git-send-email 2.10.2.windows.1 MIME-Version: 1.0 X-Originating-IP: [10.177.31.96] X-CFilter-Loop: Reflected Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: YueHaibing register_snap_client may return NULL, all the callers check it, but only print a warning. This will result in NULL pointer dereference in unregister_snap_client and other places. It has always been used like this since v2.6 Reported-by: Dan Carpenter Signed-off-by: YueHaibing --- v2: del timer in aarp_proto_init error patch --- include/linux/atalk.h | 2 +- net/appletalk/aarp.c | 15 ++++++++++++--- net/appletalk/ddp.c | 20 ++++++++++++-------- 3 files changed, 25 insertions(+), 12 deletions(-) diff --git a/include/linux/atalk.h b/include/linux/atalk.h index d5cfc0b..f6034ba 100644 --- a/include/linux/atalk.h +++ b/include/linux/atalk.h @@ -108,7 +108,7 @@ static __inline__ struct elapaarp *aarp_hdr(struct sk_buff *skb) #define AARP_RESOLVE_TIME (10 * HZ) extern struct datalink_proto *ddp_dl, *aarp_dl; -extern void aarp_proto_init(void); +extern int aarp_proto_init(void); /* Inter module exports */ diff --git a/net/appletalk/aarp.c b/net/appletalk/aarp.c index 49a16ce..420a98b 100644 --- a/net/appletalk/aarp.c +++ b/net/appletalk/aarp.c @@ -879,15 +879,24 @@ static struct notifier_block aarp_notifier = { static unsigned char aarp_snap_id[] = { 0x00, 0x00, 0x00, 0x80, 0xF3 }; -void __init aarp_proto_init(void) +int __init aarp_proto_init(void) { + int rc; + aarp_dl = register_snap_client(aarp_snap_id, aarp_rcv); - if (!aarp_dl) + if (!aarp_dl) { printk(KERN_CRIT "Unable to register AARP with SNAP.\n"); + return -ENOMEM; + } timer_setup(&aarp_timer, aarp_expire_timeout, 0); aarp_timer.expires = jiffies + sysctl_aarp_expiry_time; add_timer(&aarp_timer); - register_netdevice_notifier(&aarp_notifier); + rc = register_netdevice_notifier(&aarp_notifier); + if (rc) { + del_timer_sync(&aarp_timer); + unregister_snap_client(aarp_dl); + } + return rc; } /* Remove the AARP entries associated with a device. */ diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c index 795fbc6..709d254 100644 --- a/net/appletalk/ddp.c +++ b/net/appletalk/ddp.c @@ -1904,9 +1904,6 @@ static unsigned char ddp_snap_id[] = { 0x08, 0x00, 0x07, 0x80, 0x9B }; EXPORT_SYMBOL(atrtr_get_dev); EXPORT_SYMBOL(atalk_find_dev_addr); -static const char atalk_err_snap[] __initconst = - KERN_CRIT "Unable to register DDP with SNAP.\n"; - /* Called by proto.c on kernel start up */ static int __init atalk_init(void) { @@ -1921,17 +1918,22 @@ static int __init atalk_init(void) goto out_proto; ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv); - if (!ddp_dl) - printk(atalk_err_snap); + if (!ddp_dl) { + pr_crit("Unable to register DDP with SNAP.\n"); + goto out_sock; + } dev_add_pack(<alk_packet_type); dev_add_pack(&ppptalk_packet_type); rc = register_netdevice_notifier(&ddp_notifier); if (rc) - goto out_sock; + goto out_snap; + + rc = aarp_proto_init(); + if (rc) + goto out_dev; - aarp_proto_init(); rc = atalk_proc_init(); if (rc) goto out_aarp; @@ -1945,11 +1947,13 @@ static int __init atalk_init(void) atalk_proc_exit(); out_aarp: aarp_cleanup_module(); +out_dev: unregister_netdevice_notifier(&ddp_notifier); -out_sock: +out_snap: dev_remove_pack(&ppptalk_packet_type); dev_remove_pack(<alk_packet_type); unregister_snap_client(ddp_dl); +out_sock: sock_unregister(PF_APPLETALK); out_proto: proto_unregister(&ddp_proto);