linux/net/mctp/device.c
Lin Ma b561275d63 mctp: defer the kfree of object mdev->addrs
The function mctp_unregister() reclaims the device's relevant resource
when a netcard detaches. However, a running routine may be unaware of
this and cause the use-after-free of the mdev->addrs object.

The race condition can be demonstrated below

 cleanup thread               another thread
                          |
unregister_netdev()       |  mctp_sendmsg()
...                       |    ...
  mctp_unregister()       |    rt = mctp_route_lookup()
    ...                   |    mctl_local_output()
    kfree(mdev->addrs)    |      ...
                          |      saddr = rt->dev->addrs[0];
                          |

An attacker can adopt the (recent provided) mtcpserial driver with pty
to fake the device detaching and use the userfaultfd to increase the
race success chance (in mctp_sendmsg). The KASan report for such a POC
is shown below:

[   86.051955] ==================================================================
[   86.051955] BUG: KASAN: use-after-free in mctp_local_output+0x4e9/0xb7d
[   86.051955] Read of size 1 at addr ffff888005f298c0 by task poc/295
[   86.051955]
[   86.051955] Call Trace:
[   86.051955]  <TASK>
[   86.051955]  dump_stack_lvl+0x33/0x42
[   86.051955]  print_report.cold.13+0xb2/0x6b3
[   86.051955]  ? preempt_schedule_irq+0x57/0x80
[   86.051955]  ? mctp_local_output+0x4e9/0xb7d
[   86.051955]  kasan_report+0xa5/0x120
[   86.051955]  ? mctp_local_output+0x4e9/0xb7d
[   86.051955]  mctp_local_output+0x4e9/0xb7d
[   86.051955]  ? mctp_dev_set_key+0x79/0x79
[   86.051955]  ? copyin+0x38/0x50
[   86.051955]  ? _copy_from_iter+0x1b6/0xf20
[   86.051955]  ? sysvec_apic_timer_interrupt+0x97/0xb0
[   86.051955]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
[   86.051955]  ? mctp_local_output+0x1/0xb7d
[   86.051955]  mctp_sendmsg+0x64d/0xdb0
[   86.051955]  ? mctp_sk_close+0x20/0x20
[   86.051955]  ? __fget_light+0x2fd/0x4f0
[   86.051955]  ? mctp_sk_close+0x20/0x20
[   86.051955]  sock_sendmsg+0xdd/0x110
[   86.051955]  __sys_sendto+0x1cc/0x2a0
[   86.051955]  ? __ia32_sys_getpeername+0xa0/0xa0
[   86.051955]  ? new_sync_write+0x335/0x550
[   86.051955]  ? alloc_file+0x22f/0x500
[   86.051955]  ? __ip_do_redirect+0x820/0x1820
[   86.051955]  ? vfs_write+0x44d/0x7b0
[   86.051955]  ? vfs_write+0x44d/0x7b0
[   86.051955]  ? fput_many+0x15/0x120
[   86.051955]  ? ksys_write+0x155/0x1b0
[   86.051955]  ? __ia32_sys_read+0xa0/0xa0
[   86.051955]  __x64_sys_sendto+0xd8/0x1b0
[   86.051955]  ? exit_to_user_mode_prepare+0x2f/0x120
[   86.051955]  ? syscall_exit_to_user_mode+0x12/0x20
[   86.051955]  do_syscall_64+0x3a/0x80
[   86.051955]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   86.051955] RIP: 0033:0x7f82118a56b3
[   86.051955] RSP: 002b:00007ffdb154b110 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
[   86.051955] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f82118a56b3
[   86.051955] RDX: 0000000000000010 RSI: 00007f8211cd4000 RDI: 0000000000000007
[   86.051955] RBP: 00007ffdb154c1d0 R08: 00007ffdb154b164 R09: 000000000000000c
[   86.051955] R10: 0000000000000000 R11: 0000000000000293 R12: 000055d779800db0
[   86.051955] R13: 00007ffdb154c2b0 R14: 0000000000000000 R15: 0000000000000000
[   86.051955]  </TASK>
[   86.051955]
[   86.051955] Allocated by task 295:
[   86.051955]  kasan_save_stack+0x1c/0x40
[   86.051955]  __kasan_kmalloc+0x84/0xa0
[   86.051955]  mctp_rtm_newaddr+0x242/0x610
[   86.051955]  rtnetlink_rcv_msg+0x2fd/0x8b0
[   86.051955]  netlink_rcv_skb+0x11c/0x340
[   86.051955]  netlink_unicast+0x439/0x630
[   86.051955]  netlink_sendmsg+0x752/0xc00
[   86.051955]  sock_sendmsg+0xdd/0x110
[   86.051955]  __sys_sendto+0x1cc/0x2a0
[   86.051955]  __x64_sys_sendto+0xd8/0x1b0
[   86.051955]  do_syscall_64+0x3a/0x80
[   86.051955]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   86.051955]
[   86.051955] Freed by task 301:
[   86.051955]  kasan_save_stack+0x1c/0x40
[   86.051955]  kasan_set_track+0x21/0x30
[   86.051955]  kasan_set_free_info+0x20/0x30
[   86.051955]  __kasan_slab_free+0x104/0x170
[   86.051955]  kfree+0x8c/0x290
[   86.051955]  mctp_dev_notify+0x161/0x2c0
[   86.051955]  raw_notifier_call_chain+0x8b/0xc0
[   86.051955]  unregister_netdevice_many+0x299/0x1180
[   86.051955]  unregister_netdevice_queue+0x210/0x2f0
[   86.051955]  unregister_netdev+0x13/0x20
[   86.051955]  mctp_serial_close+0x6d/0xa0
[   86.051955]  tty_ldisc_kill+0x31/0xa0
[   86.051955]  tty_ldisc_hangup+0x24f/0x560
[   86.051955]  __tty_hangup.part.28+0x2ce/0x6b0
[   86.051955]  tty_release+0x327/0xc70
[   86.051955]  __fput+0x1df/0x8b0
[   86.051955]  task_work_run+0xca/0x150
[   86.051955]  exit_to_user_mode_prepare+0x114/0x120
[   86.051955]  syscall_exit_to_user_mode+0x12/0x20
[   86.051955]  do_syscall_64+0x46/0x80
[   86.051955]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   86.051955]
[   86.051955] The buggy address belongs to the object at ffff888005f298c0
[   86.051955]  which belongs to the cache kmalloc-8 of size 8
[   86.051955] The buggy address is located 0 bytes inside of
[   86.051955]  8-byte region [ffff888005f298c0, ffff888005f298c8)
[   86.051955]
[   86.051955] The buggy address belongs to the physical page:
[   86.051955] flags: 0x100000000000200(slab|node=0|zone=1)
[   86.051955] raw: 0100000000000200 dead000000000100 dead000000000122 ffff888005c42280
[   86.051955] raw: 0000000000000000 0000000080660066 00000001ffffffff 0000000000000000
[   86.051955] page dumped because: kasan: bad access detected
[   86.051955]
[   86.051955] Memory state around the buggy address:
[   86.051955]  ffff888005f29780: 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00
[   86.051955]  ffff888005f29800: fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc
[   86.051955] >ffff888005f29880: fc fc fc fb fc fc fc fc fa fc fc fc fc fa fc fc
[   86.051955]                                            ^
[   86.051955]  ffff888005f29900: fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc
[   86.051955]  ffff888005f29980: fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc
[   86.051955] ==================================================================

To this end, just like the commit e04480920d ("Bluetooth: defer
cleanup of resources in hci_unregister_dev()")  this patch defers the
destructive kfree(mdev->addrs) in mctp_unregister to the mctp_dev_put,
where the refcount of mdev is zero and the entire device is reclaimed.
This prevents the use-after-free because the sendmsg thread holds the
reference of mdev in the mctp_route object.

Fixes: 583be982d9 (mctp: Add device handling and netlink interface)
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Acked-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://lore.kernel.org/r/20220422114340.32346-1-linma@zju.edu.cn
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-04-26 09:14:47 +02:00

561 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Management Component Transport Protocol (MCTP) - device implementation.
*
* Copyright (c) 2021 Code Construct
* Copyright (c) 2021 Google
*/
#include <linux/if_arp.h>
#include <linux/if_link.h>
#include <linux/mctp.h>
#include <linux/netdevice.h>
#include <linux/rcupdate.h>
#include <linux/rtnetlink.h>
#include <net/addrconf.h>
#include <net/netlink.h>
#include <net/mctp.h>
#include <net/mctpdevice.h>
#include <net/sock.h>
struct mctp_dump_cb {
int h;
int idx;
size_t a_idx;
};
/* unlocked: caller must hold rcu_read_lock.
* Returned mctp_dev has its refcount incremented, or NULL if unset.
*/
struct mctp_dev *__mctp_dev_get(const struct net_device *dev)
{
struct mctp_dev *mdev = rcu_dereference(dev->mctp_ptr);
/* RCU guarantees that any mdev is still live.
* Zero refcount implies a pending free, return NULL.
*/
if (mdev)
if (!refcount_inc_not_zero(&mdev->refs))
return NULL;
return mdev;
}
/* Returned mctp_dev does not have refcount incremented. The returned pointer
* remains live while rtnl_lock is held, as that prevents mctp_unregister()
*/
struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev)
{
return rtnl_dereference(dev->mctp_ptr);
}
static int mctp_addrinfo_size(void)
{
return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
+ nla_total_size(1) // IFA_LOCAL
+ nla_total_size(1) // IFA_ADDRESS
;
}
/* flag should be NLM_F_MULTI for dump calls */
static int mctp_fill_addrinfo(struct sk_buff *skb,
struct mctp_dev *mdev, mctp_eid_t eid,
int msg_type, u32 portid, u32 seq, int flag)
{
struct ifaddrmsg *hdr;
struct nlmsghdr *nlh;
nlh = nlmsg_put(skb, portid, seq,
msg_type, sizeof(*hdr), flag);
if (!nlh)
return -EMSGSIZE;
hdr = nlmsg_data(nlh);
hdr->ifa_family = AF_MCTP;
hdr->ifa_prefixlen = 0;
hdr->ifa_flags = 0;
hdr->ifa_scope = 0;
hdr->ifa_index = mdev->dev->ifindex;
if (nla_put_u8(skb, IFA_LOCAL, eid))
goto cancel;
if (nla_put_u8(skb, IFA_ADDRESS, eid))
goto cancel;
nlmsg_end(skb, nlh);
return 0;
cancel:
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
static int mctp_dump_dev_addrinfo(struct mctp_dev *mdev, struct sk_buff *skb,
struct netlink_callback *cb)
{
struct mctp_dump_cb *mcb = (void *)cb->ctx;
u32 portid, seq;
int rc = 0;
portid = NETLINK_CB(cb->skb).portid;
seq = cb->nlh->nlmsg_seq;
for (; mcb->a_idx < mdev->num_addrs; mcb->a_idx++) {
rc = mctp_fill_addrinfo(skb, mdev, mdev->addrs[mcb->a_idx],
RTM_NEWADDR, portid, seq, NLM_F_MULTI);
if (rc < 0)
break;
}
return rc;
}
static int mctp_dump_addrinfo(struct sk_buff *skb, struct netlink_callback *cb)
{
struct mctp_dump_cb *mcb = (void *)cb->ctx;
struct net *net = sock_net(skb->sk);
struct hlist_head *head;
struct net_device *dev;
struct ifaddrmsg *hdr;
struct mctp_dev *mdev;
int ifindex;
int idx = 0, rc;
hdr = nlmsg_data(cb->nlh);
// filter by ifindex if requested
ifindex = hdr->ifa_index;
rcu_read_lock();
for (; mcb->h < NETDEV_HASHENTRIES; mcb->h++, mcb->idx = 0) {
idx = 0;
head = &net->dev_index_head[mcb->h];
hlist_for_each_entry_rcu(dev, head, index_hlist) {
if (idx >= mcb->idx &&
(ifindex == 0 || ifindex == dev->ifindex)) {
mdev = __mctp_dev_get(dev);
if (mdev) {
rc = mctp_dump_dev_addrinfo(mdev,
skb, cb);
mctp_dev_put(mdev);
// Error indicates full buffer, this
// callback will get retried.
if (rc < 0)
goto out;
}
}
idx++;
// reset for next iteration
mcb->a_idx = 0;
}
}
out:
rcu_read_unlock();
mcb->idx = idx;
return skb->len;
}
static void mctp_addr_notify(struct mctp_dev *mdev, mctp_eid_t eid, int msg_type,
struct sk_buff *req_skb, struct nlmsghdr *req_nlh)
{
u32 portid = NETLINK_CB(req_skb).portid;
struct net *net = dev_net(mdev->dev);
struct sk_buff *skb;
int rc = -ENOBUFS;
skb = nlmsg_new(mctp_addrinfo_size(), GFP_KERNEL);
if (!skb)
goto out;
rc = mctp_fill_addrinfo(skb, mdev, eid, msg_type,
portid, req_nlh->nlmsg_seq, 0);
if (rc < 0) {
WARN_ON_ONCE(rc == -EMSGSIZE);
goto out;
}
rtnl_notify(skb, net, portid, RTNLGRP_MCTP_IFADDR, req_nlh, GFP_KERNEL);
return;
out:
kfree_skb(skb);
rtnl_set_sk_err(net, RTNLGRP_MCTP_IFADDR, rc);
}
static const struct nla_policy ifa_mctp_policy[IFA_MAX + 1] = {
[IFA_ADDRESS] = { .type = NLA_U8 },
[IFA_LOCAL] = { .type = NLA_U8 },
};
static int mctp_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct nlattr *tb[IFA_MAX + 1];
struct net_device *dev;
struct mctp_addr *addr;
struct mctp_dev *mdev;
struct ifaddrmsg *ifm;
unsigned long flags;
u8 *tmp_addrs;
int rc;
rc = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_mctp_policy,
extack);
if (rc < 0)
return rc;
ifm = nlmsg_data(nlh);
if (tb[IFA_LOCAL])
addr = nla_data(tb[IFA_LOCAL]);
else if (tb[IFA_ADDRESS])
addr = nla_data(tb[IFA_ADDRESS]);
else
return -EINVAL;
/* find device */
dev = __dev_get_by_index(net, ifm->ifa_index);
if (!dev)
return -ENODEV;
mdev = mctp_dev_get_rtnl(dev);
if (!mdev)
return -ENODEV;
if (!mctp_address_unicast(addr->s_addr))
return -EINVAL;
/* Prevent duplicates. Under RTNL so don't need to lock for reading */
if (memchr(mdev->addrs, addr->s_addr, mdev->num_addrs))
return -EEXIST;
tmp_addrs = kmalloc(mdev->num_addrs + 1, GFP_KERNEL);
if (!tmp_addrs)
return -ENOMEM;
memcpy(tmp_addrs, mdev->addrs, mdev->num_addrs);
tmp_addrs[mdev->num_addrs] = addr->s_addr;
/* Lock to write */
spin_lock_irqsave(&mdev->addrs_lock, flags);
mdev->num_addrs++;
swap(mdev->addrs, tmp_addrs);
spin_unlock_irqrestore(&mdev->addrs_lock, flags);
kfree(tmp_addrs);
mctp_addr_notify(mdev, addr->s_addr, RTM_NEWADDR, skb, nlh);
mctp_route_add_local(mdev, addr->s_addr);
return 0;
}
static int mctp_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct nlattr *tb[IFA_MAX + 1];
struct net_device *dev;
struct mctp_addr *addr;
struct mctp_dev *mdev;
struct ifaddrmsg *ifm;
unsigned long flags;
u8 *pos;
int rc;
rc = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_mctp_policy,
extack);
if (rc < 0)
return rc;
ifm = nlmsg_data(nlh);
if (tb[IFA_LOCAL])
addr = nla_data(tb[IFA_LOCAL]);
else if (tb[IFA_ADDRESS])
addr = nla_data(tb[IFA_ADDRESS]);
else
return -EINVAL;
/* find device */
dev = __dev_get_by_index(net, ifm->ifa_index);
if (!dev)
return -ENODEV;
mdev = mctp_dev_get_rtnl(dev);
if (!mdev)
return -ENODEV;
pos = memchr(mdev->addrs, addr->s_addr, mdev->num_addrs);
if (!pos)
return -ENOENT;
rc = mctp_route_remove_local(mdev, addr->s_addr);
// we can ignore -ENOENT in the case a route was already removed
if (rc < 0 && rc != -ENOENT)
return rc;
spin_lock_irqsave(&mdev->addrs_lock, flags);
memmove(pos, pos + 1, mdev->num_addrs - 1 - (pos - mdev->addrs));
mdev->num_addrs--;
spin_unlock_irqrestore(&mdev->addrs_lock, flags);
mctp_addr_notify(mdev, addr->s_addr, RTM_DELADDR, skb, nlh);
return 0;
}
void mctp_dev_hold(struct mctp_dev *mdev)
{
refcount_inc(&mdev->refs);
}
void mctp_dev_put(struct mctp_dev *mdev)
{
if (mdev && refcount_dec_and_test(&mdev->refs)) {
kfree(mdev->addrs);
dev_put(mdev->dev);
kfree_rcu(mdev, rcu);
}
}
void mctp_dev_release_key(struct mctp_dev *dev, struct mctp_sk_key *key)
__must_hold(&key->lock)
{
if (!dev)
return;
if (dev->ops && dev->ops->release_flow)
dev->ops->release_flow(dev, key);
key->dev = NULL;
mctp_dev_put(dev);
}
void mctp_dev_set_key(struct mctp_dev *dev, struct mctp_sk_key *key)
__must_hold(&key->lock)
{
mctp_dev_hold(dev);
key->dev = dev;
}
static struct mctp_dev *mctp_add_dev(struct net_device *dev)
{
struct mctp_dev *mdev;
ASSERT_RTNL();
mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
if (!mdev)
return ERR_PTR(-ENOMEM);
spin_lock_init(&mdev->addrs_lock);
mdev->net = mctp_default_net(dev_net(dev));
/* associate to net_device */
refcount_set(&mdev->refs, 1);
rcu_assign_pointer(dev->mctp_ptr, mdev);
dev_hold(dev);
mdev->dev = dev;
return mdev;
}
static int mctp_fill_link_af(struct sk_buff *skb,
const struct net_device *dev, u32 ext_filter_mask)
{
struct mctp_dev *mdev;
mdev = mctp_dev_get_rtnl(dev);
if (!mdev)
return -ENODATA;
if (nla_put_u32(skb, IFLA_MCTP_NET, mdev->net))
return -EMSGSIZE;
return 0;
}
static size_t mctp_get_link_af_size(const struct net_device *dev,
u32 ext_filter_mask)
{
struct mctp_dev *mdev;
unsigned int ret;
/* caller holds RCU */
mdev = __mctp_dev_get(dev);
if (!mdev)
return 0;
ret = nla_total_size(4); /* IFLA_MCTP_NET */
mctp_dev_put(mdev);
return ret;
}
static const struct nla_policy ifla_af_mctp_policy[IFLA_MCTP_MAX + 1] = {
[IFLA_MCTP_NET] = { .type = NLA_U32 },
};
static int mctp_set_link_af(struct net_device *dev, const struct nlattr *attr,
struct netlink_ext_ack *extack)
{
struct nlattr *tb[IFLA_MCTP_MAX + 1];
struct mctp_dev *mdev;
int rc;
rc = nla_parse_nested(tb, IFLA_MCTP_MAX, attr, ifla_af_mctp_policy,
NULL);
if (rc)
return rc;
mdev = mctp_dev_get_rtnl(dev);
if (!mdev)
return 0;
if (tb[IFLA_MCTP_NET])
WRITE_ONCE(mdev->net, nla_get_u32(tb[IFLA_MCTP_NET]));
return 0;
}
/* Matches netdev types that should have MCTP handling */
static bool mctp_known(struct net_device *dev)
{
/* only register specific types (inc. NONE for TUN devices) */
return dev->type == ARPHRD_MCTP ||
dev->type == ARPHRD_LOOPBACK ||
dev->type == ARPHRD_NONE;
}
static void mctp_unregister(struct net_device *dev)
{
struct mctp_dev *mdev;
mdev = mctp_dev_get_rtnl(dev);
if (mdev && !mctp_known(dev)) {
// Sanity check, should match what was set in mctp_register
netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d",
__func__, dev->type);
return;
}
if (!mdev)
return;
RCU_INIT_POINTER(mdev->dev->mctp_ptr, NULL);
mctp_route_remove_dev(mdev);
mctp_neigh_remove_dev(mdev);
mctp_dev_put(mdev);
}
static int mctp_register(struct net_device *dev)
{
struct mctp_dev *mdev;
/* Already registered? */
mdev = rtnl_dereference(dev->mctp_ptr);
if (mdev) {
if (!mctp_known(dev))
netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d",
__func__, dev->type);
return 0;
}
/* only register specific types */
if (!mctp_known(dev))
return 0;
mdev = mctp_add_dev(dev);
if (IS_ERR(mdev))
return PTR_ERR(mdev);
return 0;
}
static int mctp_dev_notify(struct notifier_block *this, unsigned long event,
void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
int rc;
switch (event) {
case NETDEV_REGISTER:
rc = mctp_register(dev);
if (rc)
return notifier_from_errno(rc);
break;
case NETDEV_UNREGISTER:
mctp_unregister(dev);
break;
}
return NOTIFY_OK;
}
static int mctp_register_netdevice(struct net_device *dev,
const struct mctp_netdev_ops *ops)
{
struct mctp_dev *mdev;
mdev = mctp_add_dev(dev);
if (IS_ERR(mdev))
return PTR_ERR(mdev);
mdev->ops = ops;
return register_netdevice(dev);
}
int mctp_register_netdev(struct net_device *dev,
const struct mctp_netdev_ops *ops)
{
int rc;
rtnl_lock();
rc = mctp_register_netdevice(dev, ops);
rtnl_unlock();
return rc;
}
EXPORT_SYMBOL_GPL(mctp_register_netdev);
void mctp_unregister_netdev(struct net_device *dev)
{
unregister_netdev(dev);
}
EXPORT_SYMBOL_GPL(mctp_unregister_netdev);
static struct rtnl_af_ops mctp_af_ops = {
.family = AF_MCTP,
.fill_link_af = mctp_fill_link_af,
.get_link_af_size = mctp_get_link_af_size,
.set_link_af = mctp_set_link_af,
};
static struct notifier_block mctp_dev_nb = {
.notifier_call = mctp_dev_notify,
.priority = ADDRCONF_NOTIFY_PRIORITY,
};
void __init mctp_device_init(void)
{
register_netdevice_notifier(&mctp_dev_nb);
rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_GETADDR,
NULL, mctp_dump_addrinfo, 0);
rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_NEWADDR,
mctp_rtm_newaddr, NULL, 0);
rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_DELADDR,
mctp_rtm_deladdr, NULL, 0);
rtnl_af_register(&mctp_af_ops);
}
void __exit mctp_device_exit(void)
{
rtnl_af_unregister(&mctp_af_ops);
rtnl_unregister(PF_MCTP, RTM_DELADDR);
rtnl_unregister(PF_MCTP, RTM_NEWADDR);
rtnl_unregister(PF_MCTP, RTM_GETADDR);
unregister_netdevice_notifier(&mctp_dev_nb);
}