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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 4E064C43603 for ; Sun, 8 Dec 2019 13:55:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2B83E206E0 for ; Sun, 8 Dec 2019 13:55:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726795AbfLHNz0 (ORCPT ); Sun, 8 Dec 2019 08:55:26 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:60536 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726916AbfLHNyq (ORCPT ); Sun, 8 Dec 2019 08:54:46 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1idx1G-0007he-Ij; Sun, 08 Dec 2019 13:54:42 +0000 Received: from ben by deadeye with local (Exim 4.93-RC1) (envelope-from ) id 1idx1E-0002PF-Vg; Sun, 08 Dec 2019 13:54:40 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "David S. Miller" , "YueHaibing" , "Dan Carpenter" Date: Sun, 08 Dec 2019 13:53:44 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 60/72] appletalk: Fix potential NULL pointer dereference in unregister_snap_client In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 3.16.79-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: YueHaibing commit 9804501fa1228048857910a6bf23e085aade37cc upstream. 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 Signed-off-by: David S. Miller [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- include/linux/atalk.h | 2 +- net/appletalk/aarp.c | 15 ++++++++++++--- net/appletalk/ddp.c | 20 ++++++++++++-------- 3 files changed, 25 insertions(+), 12 deletions(-) --- a/include/linux/atalk.h +++ b/include/linux/atalk.h @@ -107,7 +107,7 @@ static __inline__ struct elapaarp *aarp_ #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 */ --- a/net/appletalk/aarp.c +++ b/net/appletalk/aarp.c @@ -879,15 +879,24 @@ static struct notifier_block aarp_notifi 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; + } setup_timer(&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. */ --- a/net/appletalk/ddp.c +++ b/net/appletalk/ddp.c @@ -1912,9 +1912,6 @@ static unsigned char ddp_snap_id[] = { 0 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) { @@ -1929,17 +1926,22 @@ 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; @@ -1953,11 +1955,13 @@ out_proc: 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);