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56b08fdcf6
To repeat:
$ sudo ip link del hsr0
BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
IP: [<ffffffff8187f495>] hsr_del_port+0x15/0xa0
etc...
Bug description:
As part of the hsr master device destruction, hsr_del_port() is called for each of
the hsr ports. At each such call, the master device is updated regarding features
and mtu. When the master device is freed before the slave interfaces, master will
be NULL in hsr_del_port(), which led to a NULL pointer dereference.
Additionally, dev_put() was called on the master device itself in hsr_del_port(),
causing a refcnt error.
A third bug in the same code path was that the rtnl lock was not taken before
hsr_del_port() was called as part of hsr_dev_destroy().
The reporter (Nicolas Dichtel) also said: "hsr_netdev_notify() supposes that the
port will always be available when the notification is for an hsr interface. It's
wrong. For example, netdev_wait_allrefs() may resend NETDEV_UNREGISTER.". As a
precaution against this, a check for port == NULL was added in hsr_dev_notify().
Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Fixes: 51f3c60531 ("net/hsr: Move slave init to hsr_slave.c.")
Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
137 lines
3.2 KiB
C
137 lines
3.2 KiB
C
/* Copyright 2011-2014 Autronica Fire and Security AS
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* Author(s):
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* 2011-2014 Arvid Brodin, arvid.brodin@alten.se
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*/
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#include <linux/netdevice.h>
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#include <linux/rculist.h>
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#include <linux/timer.h>
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#include <linux/etherdevice.h>
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#include "hsr_main.h"
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#include "hsr_device.h"
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#include "hsr_netlink.h"
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#include "hsr_framereg.h"
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#include "hsr_slave.h"
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static int hsr_netdev_notify(struct notifier_block *nb, unsigned long event,
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void *ptr)
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{
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struct net_device *dev;
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struct hsr_port *port, *master;
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struct hsr_priv *hsr;
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int mtu_max;
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int res;
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dev = netdev_notifier_info_to_dev(ptr);
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port = hsr_port_get_rtnl(dev);
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if (port == NULL) {
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if (!is_hsr_master(dev))
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return NOTIFY_DONE; /* Not an HSR device */
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hsr = netdev_priv(dev);
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port = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
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if (port == NULL) {
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/* Resend of notification concerning removed device? */
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return NOTIFY_DONE;
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}
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} else {
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hsr = port->hsr;
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}
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switch (event) {
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case NETDEV_UP: /* Administrative state DOWN */
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case NETDEV_DOWN: /* Administrative state UP */
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case NETDEV_CHANGE: /* Link (carrier) state changes */
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hsr_check_carrier_and_operstate(hsr);
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break;
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case NETDEV_CHANGEADDR:
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if (port->type == HSR_PT_MASTER) {
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/* This should not happen since there's no
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* ndo_set_mac_address() for HSR devices - i.e. not
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* supported.
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*/
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break;
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}
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master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
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if (port->type == HSR_PT_SLAVE_A) {
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ether_addr_copy(master->dev->dev_addr, dev->dev_addr);
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call_netdevice_notifiers(NETDEV_CHANGEADDR, master->dev);
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}
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/* Make sure we recognize frames from ourselves in hsr_rcv() */
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port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
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res = hsr_create_self_node(&hsr->self_node_db,
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master->dev->dev_addr,
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port ?
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port->dev->dev_addr :
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master->dev->dev_addr);
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if (res)
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netdev_warn(master->dev,
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"Could not update HSR node address.\n");
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break;
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case NETDEV_CHANGEMTU:
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if (port->type == HSR_PT_MASTER)
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break; /* Handled in ndo_change_mtu() */
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mtu_max = hsr_get_max_mtu(port->hsr);
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master = hsr_port_get_hsr(port->hsr, HSR_PT_MASTER);
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master->dev->mtu = mtu_max;
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break;
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case NETDEV_UNREGISTER:
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hsr_del_port(port);
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break;
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case NETDEV_PRE_TYPE_CHANGE:
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/* HSR works only on Ethernet devices. Refuse slave to change
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* its type.
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*/
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return NOTIFY_BAD;
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}
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return NOTIFY_DONE;
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}
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struct hsr_port *hsr_port_get_hsr(struct hsr_priv *hsr, enum hsr_port_type pt)
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{
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struct hsr_port *port;
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hsr_for_each_port(hsr, port)
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if (port->type == pt)
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return port;
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return NULL;
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}
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static struct notifier_block hsr_nb = {
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.notifier_call = hsr_netdev_notify, /* Slave event notifications */
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};
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static int __init hsr_init(void)
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{
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int res;
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BUILD_BUG_ON(sizeof(struct hsr_tag) != HSR_HLEN);
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register_netdevice_notifier(&hsr_nb);
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res = hsr_netlink_init();
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return res;
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}
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static void __exit hsr_exit(void)
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{
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unregister_netdevice_notifier(&hsr_nb);
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hsr_netlink_exit();
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}
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module_init(hsr_init);
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module_exit(hsr_exit);
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MODULE_LICENSE("GPL");
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