From 39de8cc3678f5cd1f4e0ae274c20acabbd85a8b1 Mon Sep 17 00:00:00 2001 From: YueHaibing Date: Thu, 14 Mar 2019 13:47:59 +0800 Subject: appletalk: Fix potential NULL pointer dereference in unregister_snap_client 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 <4.15: adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- net/appletalk/aarp.c | 15 ++++++++++++--- net/appletalk/ddp.c | 20 ++++++++++++-------- 2 files changed, 24 insertions(+), 11 deletions(-) (limited to 'net/appletalk') diff --git a/net/appletalk/aarp.c b/net/appletalk/aarp.c index 8ad3ec2610b6..b9e85a4751a6 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; + } 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. */ diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c index 475f332b1ad2..ab59c56e0513 100644 --- a/net/appletalk/ddp.c +++ b/net/appletalk/ddp.c @@ -1911,9 +1911,6 @@ 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) { @@ -1928,17 +1925,22 @@ 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; @@ -1952,11 +1954,13 @@ 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); -- cgit v1.2.3