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linux/net/netlink/af_netlink.c
Daniel Borkmann 5ffd5cddd4 net: netlink: filter particular protocols from analyzers 
Fix finer-grained control and let only a whitelist of allowed netlink
protocols pass, in our case related to networking. If later on, other
subsystems decide they want to add their protocol as well to the list
of allowed protocols they shall simply add it. While at it, we also
need to tell what protocol is in use otherwise BPF_S_ANC_PROTOCOL can
not pick it up (as it's not filled out).

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-09-06 14:43:48 -04:00

3116 lines
70 KiB
C
Raw Blame History

/*
* NETLINK Kernel-user communication protocol.
*
* Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
* Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
* Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
* added netlink_proto_exit
* Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
* use nlk_sk, as sk->protinfo is on a diet 8)
* Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
* - inc module use count of module that owns
* the kernel socket in case userspace opens
* socket of same protocol
* - remove all module support, since netlink is
* mandatory if CONFIG_NET=y these days
*/
#include <linux/module.h>
#include <linux/capability.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/socket.h>
#include <linux/un.h>
#include <linux/fcntl.h>
#include <linux/termios.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/notifier.h>
#include <linux/security.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/random.h>
#include <linux/bitops.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/audit.h>
#include <linux/mutex.h>
#include <linux/vmalloc.h>
#include <linux/if_arp.h>
#include <asm/cacheflush.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/scm.h>
#include <net/netlink.h>
#include "af_netlink.h"
struct listeners {
struct rcu_head rcu;
unsigned long masks[0];
};
/* state bits */
#define NETLINK_CONGESTED 0x0
/* flags */
#define NETLINK_KERNEL_SOCKET 0x1
#define NETLINK_RECV_PKTINFO 0x2
#define NETLINK_BROADCAST_SEND_ERROR 0x4
#define NETLINK_RECV_NO_ENOBUFS 0x8
static inline int netlink_is_kernel(struct sock *sk)
{
return nlk_sk(sk)->flags & NETLINK_KERNEL_SOCKET;
}
struct netlink_table *nl_table;
EXPORT_SYMBOL_GPL(nl_table);
static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
static int netlink_dump(struct sock *sk);
static void netlink_skb_destructor(struct sk_buff *skb);
DEFINE_RWLOCK(nl_table_lock);
EXPORT_SYMBOL_GPL(nl_table_lock);
static atomic_t nl_table_users = ATOMIC_INIT(0);
#define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
static ATOMIC_NOTIFIER_HEAD(netlink_chain);
static DEFINE_SPINLOCK(netlink_tap_lock);
static struct list_head netlink_tap_all __read_mostly;
static inline u32 netlink_group_mask(u32 group)
{
return group ? 1 << (group - 1) : 0;
}
static inline struct hlist_head *nl_portid_hashfn(struct nl_portid_hash *hash, u32 portid)
{
return &hash->table[jhash_1word(portid, hash->rnd) & hash->mask];
}
int netlink_add_tap(struct netlink_tap *nt)
{
if (unlikely(nt->dev->type != ARPHRD_NETLINK))
return -EINVAL;
spin_lock(&netlink_tap_lock);
list_add_rcu(&nt->list, &netlink_tap_all);
spin_unlock(&netlink_tap_lock);
if (nt->module)
__module_get(nt->module);
return 0;
}
EXPORT_SYMBOL_GPL(netlink_add_tap);
int __netlink_remove_tap(struct netlink_tap *nt)
{
bool found = false;
struct netlink_tap *tmp;
spin_lock(&netlink_tap_lock);
list_for_each_entry(tmp, &netlink_tap_all, list) {
if (nt == tmp) {
list_del_rcu(&nt->list);
found = true;
goto out;
}
}
pr_warn("__netlink_remove_tap: %p not found\n", nt);
out:
spin_unlock(&netlink_tap_lock);
if (found && nt->module)
module_put(nt->module);
return found ? 0 : -ENODEV;
}
EXPORT_SYMBOL_GPL(__netlink_remove_tap);
int netlink_remove_tap(struct netlink_tap *nt)
{
int ret;
ret = __netlink_remove_tap(nt);
synchronize_net();
return ret;
}
EXPORT_SYMBOL_GPL(netlink_remove_tap);
static bool netlink_filter_tap(const struct sk_buff *skb)
{
struct sock *sk = skb->sk;
bool pass = false;
/* We take the more conservative approach and
* whitelist socket protocols that may pass.
*/
switch (sk->sk_protocol) {
case NETLINK_ROUTE:
case NETLINK_USERSOCK:
case NETLINK_SOCK_DIAG:
case NETLINK_NFLOG:
case NETLINK_XFRM:
case NETLINK_FIB_LOOKUP:
case NETLINK_NETFILTER:
case NETLINK_GENERIC:
pass = true;
break;
}
return pass;
}
static int __netlink_deliver_tap_skb(struct sk_buff *skb,
struct net_device *dev)
{
struct sk_buff *nskb;
struct sock *sk = skb->sk;
int ret = -ENOMEM;
dev_hold(dev);
nskb = skb_clone(skb, GFP_ATOMIC);
if (nskb) {
nskb->dev = dev;
nskb->protocol = htons((u16) sk->sk_protocol);
ret = dev_queue_xmit(nskb);
if (unlikely(ret > 0))
ret = net_xmit_errno(ret);
}
dev_put(dev);
return ret;
}
static void __netlink_deliver_tap(struct sk_buff *skb)
{
int ret;
struct netlink_tap *tmp;
if (!netlink_filter_tap(skb))
return;
list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
ret = __netlink_deliver_tap_skb(skb, tmp->dev);
if (unlikely(ret))
break;
}
}
static void netlink_deliver_tap(struct sk_buff *skb)
{
rcu_read_lock();
if (unlikely(!list_empty(&netlink_tap_all)))
__netlink_deliver_tap(skb);
rcu_read_unlock();
}
static void netlink_overrun(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
if (!test_and_set_bit(NETLINK_CONGESTED, &nlk_sk(sk)->state)) {
sk->sk_err = ENOBUFS;
sk->sk_error_report(sk);
}
}
atomic_inc(&sk->sk_drops);
}
static void netlink_rcv_wake(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (skb_queue_empty(&sk->sk_receive_queue))
clear_bit(NETLINK_CONGESTED, &nlk->state);
if (!test_bit(NETLINK_CONGESTED, &nlk->state))
wake_up_interruptible(&nlk->wait);
}
#ifdef CONFIG_NETLINK_MMAP
static bool netlink_skb_is_mmaped(const struct sk_buff *skb)
{
return NETLINK_CB(skb).flags & NETLINK_SKB_MMAPED;
}
static bool netlink_rx_is_mmaped(struct sock *sk)
{
return nlk_sk(sk)->rx_ring.pg_vec != NULL;
}
static bool netlink_tx_is_mmaped(struct sock *sk)
{
return nlk_sk(sk)->tx_ring.pg_vec != NULL;
}
static __pure struct page *pgvec_to_page(const void *addr)
{
if (is_vmalloc_addr(addr))
return vmalloc_to_page(addr);
else
return virt_to_page(addr);
}
static void free_pg_vec(void **pg_vec, unsigned int order, unsigned int len)
{
unsigned int i;
for (i = 0; i < len; i++) {
if (pg_vec[i] != NULL) {
if (is_vmalloc_addr(pg_vec[i]))
vfree(pg_vec[i]);
else
free_pages((unsigned long)pg_vec[i], order);
}
}
kfree(pg_vec);
}
static void *alloc_one_pg_vec_page(unsigned long order)
{
void *buffer;
gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO |
__GFP_NOWARN | __GFP_NORETRY;
buffer = (void *)__get_free_pages(gfp_flags, order);
if (buffer != NULL)
return buffer;
buffer = vzalloc((1 << order) * PAGE_SIZE);
if (buffer != NULL)
return buffer;
gfp_flags &= ~__GFP_NORETRY;
return (void *)__get_free_pages(gfp_flags, order);
}
static void **alloc_pg_vec(struct netlink_sock *nlk,
struct nl_mmap_req *req, unsigned int order)
{
unsigned int block_nr = req->nm_block_nr;
unsigned int i;
void **pg_vec;
pg_vec = kcalloc(block_nr, sizeof(void *), GFP_KERNEL);
if (pg_vec == NULL)
return NULL;
for (i = 0; i < block_nr; i++) {
pg_vec[i] = alloc_one_pg_vec_page(order);
if (pg_vec[i] == NULL)
goto err1;
}
return pg_vec;
err1:
free_pg_vec(pg_vec, order, block_nr);
return NULL;
}
static int netlink_set_ring(struct sock *sk, struct nl_mmap_req *req,
bool closing, bool tx_ring)
{
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_ring *ring;
struct sk_buff_head *queue;
void **pg_vec = NULL;
unsigned int order = 0;
int err;
ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring;
queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
if (!closing) {
if (atomic_read(&nlk->mapped))
return -EBUSY;
if (atomic_read(&ring->pending))
return -EBUSY;
}
if (req->nm_block_nr) {
if (ring->pg_vec != NULL)
return -EBUSY;
if ((int)req->nm_block_size <= 0)
return -EINVAL;
if (!IS_ALIGNED(req->nm_block_size, PAGE_SIZE))
return -EINVAL;
if (req->nm_frame_size < NL_MMAP_HDRLEN)
return -EINVAL;
if (!IS_ALIGNED(req->nm_frame_size, NL_MMAP_MSG_ALIGNMENT))
return -EINVAL;
ring->frames_per_block = req->nm_block_size /
req->nm_frame_size;
if (ring->frames_per_block == 0)
return -EINVAL;
if (ring->frames_per_block * req->nm_block_nr !=
req->nm_frame_nr)
return -EINVAL;
order = get_order(req->nm_block_size);
pg_vec = alloc_pg_vec(nlk, req, order);
if (pg_vec == NULL)
return -ENOMEM;
} else {
if (req->nm_frame_nr)
return -EINVAL;
}
err = -EBUSY;
mutex_lock(&nlk->pg_vec_lock);
if (closing || atomic_read(&nlk->mapped) == 0) {
err = 0;
spin_lock_bh(&queue->lock);
ring->frame_max = req->nm_frame_nr - 1;
ring->head = 0;
ring->frame_size = req->nm_frame_size;
ring->pg_vec_pages = req->nm_block_size / PAGE_SIZE;
swap(ring->pg_vec_len, req->nm_block_nr);
swap(ring->pg_vec_order, order);
swap(ring->pg_vec, pg_vec);
__skb_queue_purge(queue);
spin_unlock_bh(&queue->lock);
WARN_ON(atomic_read(&nlk->mapped));
}
mutex_unlock(&nlk->pg_vec_lock);
if (pg_vec)
free_pg_vec(pg_vec, order, req->nm_block_nr);
return err;
}
static void netlink_mm_open(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct socket *sock = file->private_data;
struct sock *sk = sock->sk;
if (sk)
atomic_inc(&nlk_sk(sk)->mapped);
}
static void netlink_mm_close(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct socket *sock = file->private_data;
struct sock *sk = sock->sk;
if (sk)
atomic_dec(&nlk_sk(sk)->mapped);
}
static const struct vm_operations_struct netlink_mmap_ops = {
.open = netlink_mm_open,
.close = netlink_mm_close,
};
static int netlink_mmap(struct file *file, struct socket *sock,
struct vm_area_struct *vma)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_ring *ring;
unsigned long start, size, expected;
unsigned int i;
int err = -EINVAL;
if (vma->vm_pgoff)
return -EINVAL;
mutex_lock(&nlk->pg_vec_lock);
expected = 0;
for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
if (ring->pg_vec == NULL)
continue;
expected += ring->pg_vec_len * ring->pg_vec_pages * PAGE_SIZE;
}
if (expected == 0)
goto out;
size = vma->vm_end - vma->vm_start;
if (size != expected)
goto out;
start = vma->vm_start;
for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
if (ring->pg_vec == NULL)
continue;
for (i = 0; i < ring->pg_vec_len; i++) {
struct page *page;
void *kaddr = ring->pg_vec[i];
unsigned int pg_num;
for (pg_num = 0; pg_num < ring->pg_vec_pages; pg_num++) {
page = pgvec_to_page(kaddr);
err = vm_insert_page(vma, start, page);
if (err < 0)
goto out;
start += PAGE_SIZE;
kaddr += PAGE_SIZE;
}
}
}
atomic_inc(&nlk->mapped);
vma->vm_ops = &netlink_mmap_ops;
err = 0;
out:
mutex_unlock(&nlk->pg_vec_lock);
return err;
}
static void netlink_frame_flush_dcache(const struct nl_mmap_hdr *hdr)
{
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
struct page *p_start, *p_end;
/* First page is flushed through netlink_{get,set}_status */
p_start = pgvec_to_page(hdr + PAGE_SIZE);
p_end = pgvec_to_page((void *)hdr + NL_MMAP_HDRLEN + hdr->nm_len - 1);
while (p_start <= p_end) {
flush_dcache_page(p_start);
p_start++;
}
#endif
}
static enum nl_mmap_status netlink_get_status(const struct nl_mmap_hdr *hdr)
{
smp_rmb();
flush_dcache_page(pgvec_to_page(hdr));
return hdr->nm_status;
}
static void netlink_set_status(struct nl_mmap_hdr *hdr,
enum nl_mmap_status status)
{
hdr->nm_status = status;
flush_dcache_page(pgvec_to_page(hdr));
smp_wmb();
}
static struct nl_mmap_hdr *
__netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos)
{
unsigned int pg_vec_pos, frame_off;
pg_vec_pos = pos / ring->frames_per_block;
frame_off = pos % ring->frames_per_block;
return ring->pg_vec[pg_vec_pos] + (frame_off * ring->frame_size);
}
static struct nl_mmap_hdr *
netlink_lookup_frame(const struct netlink_ring *ring, unsigned int pos,
enum nl_mmap_status status)
{
struct nl_mmap_hdr *hdr;
hdr = __netlink_lookup_frame(ring, pos);
if (netlink_get_status(hdr) != status)
return NULL;
return hdr;
}
static struct nl_mmap_hdr *
netlink_current_frame(const struct netlink_ring *ring,
enum nl_mmap_status status)
{
return netlink_lookup_frame(ring, ring->head, status);
}
static struct nl_mmap_hdr *
netlink_previous_frame(const struct netlink_ring *ring,
enum nl_mmap_status status)
{
unsigned int prev;
prev = ring->head ? ring->head - 1 : ring->frame_max;
return netlink_lookup_frame(ring, prev, status);
}
static void netlink_increment_head(struct netlink_ring *ring)
{
ring->head = ring->head != ring->frame_max ? ring->head + 1 : 0;
}
static void netlink_forward_ring(struct netlink_ring *ring)
{
unsigned int head = ring->head, pos = head;
const struct nl_mmap_hdr *hdr;
do {
hdr = __netlink_lookup_frame(ring, pos);
if (hdr->nm_status == NL_MMAP_STATUS_UNUSED)
break;
if (hdr->nm_status != NL_MMAP_STATUS_SKIP)
break;
netlink_increment_head(ring);
} while (ring->head != head);
}
static bool netlink_dump_space(struct netlink_sock *nlk)
{
struct netlink_ring *ring = &nlk->rx_ring;
struct nl_mmap_hdr *hdr;
unsigned int n;
hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
if (hdr == NULL)
return false;
n = ring->head + ring->frame_max / 2;
if (n > ring->frame_max)
n -= ring->frame_max;
hdr = __netlink_lookup_frame(ring, n);
return hdr->nm_status == NL_MMAP_STATUS_UNUSED;
}
static unsigned int netlink_poll(struct file *file, struct socket *sock,
poll_table *wait)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
unsigned int mask;
int err;
if (nlk->rx_ring.pg_vec != NULL) {
/* Memory mapped sockets don't call recvmsg(), so flow control
* for dumps is performed here. A dump is allowed to continue
* if at least half the ring is unused.
*/
while (nlk->cb_running && netlink_dump_space(nlk)) {
err = netlink_dump(sk);
if (err < 0) {
sk->sk_err = err;
sk->sk_error_report(sk);
break;
}
}
netlink_rcv_wake(sk);
}
mask = datagram_poll(file, sock, wait);
spin_lock_bh(&sk->sk_receive_queue.lock);
if (nlk->rx_ring.pg_vec) {
netlink_forward_ring(&nlk->rx_ring);
if (!netlink_previous_frame(&nlk->rx_ring, NL_MMAP_STATUS_UNUSED))
mask |= POLLIN | POLLRDNORM;
}
spin_unlock_bh(&sk->sk_receive_queue.lock);
spin_lock_bh(&sk->sk_write_queue.lock);
if (nlk->tx_ring.pg_vec) {
if (netlink_current_frame(&nlk->tx_ring, NL_MMAP_STATUS_UNUSED))
mask |= POLLOUT | POLLWRNORM;
}
spin_unlock_bh(&sk->sk_write_queue.lock);
return mask;
}
static struct nl_mmap_hdr *netlink_mmap_hdr(struct sk_buff *skb)
{
return (struct nl_mmap_hdr *)(skb->head - NL_MMAP_HDRLEN);
}
static void netlink_ring_setup_skb(struct sk_buff *skb, struct sock *sk,
struct netlink_ring *ring,
struct nl_mmap_hdr *hdr)
{
unsigned int size;
void *data;
size = ring->frame_size - NL_MMAP_HDRLEN;
data = (void *)hdr + NL_MMAP_HDRLEN;
skb->head = data;
skb->data = data;
skb_reset_tail_pointer(skb);
skb->end = skb->tail + size;
skb->len = 0;
skb->destructor = netlink_skb_destructor;
NETLINK_CB(skb).flags |= NETLINK_SKB_MMAPED;
NETLINK_CB(skb).sk = sk;
}
static int netlink_mmap_sendmsg(struct sock *sk, struct msghdr *msg,
u32 dst_portid, u32 dst_group,
struct sock_iocb *siocb)
{
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_ring *ring;
struct nl_mmap_hdr *hdr;
struct sk_buff *skb;
unsigned int maxlen;
bool excl = true;
int err = 0, len = 0;
/* Netlink messages are validated by the receiver before processing.
* In order to avoid userspace changing the contents of the message
* after validation, the socket and the ring may only be used by a
* single process, otherwise we fall back to copying.
*/
if (atomic_long_read(&sk->sk_socket->file->f_count) > 2 ||
atomic_read(&nlk->mapped) > 1)
excl = false;
mutex_lock(&nlk->pg_vec_lock);
ring = &nlk->tx_ring;
maxlen = ring->frame_size - NL_MMAP_HDRLEN;
do {
hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID);
if (hdr == NULL) {
if (!(msg->msg_flags & MSG_DONTWAIT) &&
atomic_read(&nlk->tx_ring.pending))
schedule();
continue;
}
if (hdr->nm_len > maxlen) {
err = -EINVAL;
goto out;
}
netlink_frame_flush_dcache(hdr);
if (likely(dst_portid == 0 && dst_group == 0 && excl)) {
skb = alloc_skb_head(GFP_KERNEL);
if (skb == NULL) {
err = -ENOBUFS;
goto out;
}
sock_hold(sk);
netlink_ring_setup_skb(skb, sk, ring, hdr);
NETLINK_CB(skb).flags |= NETLINK_SKB_TX;
__skb_put(skb, hdr->nm_len);
netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
atomic_inc(&ring->pending);
} else {
skb = alloc_skb(hdr->nm_len, GFP_KERNEL);
if (skb == NULL) {
err = -ENOBUFS;
goto out;
}
__skb_put(skb, hdr->nm_len);
memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, hdr->nm_len);
netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
}
netlink_increment_head(ring);
NETLINK_CB(skb).portid = nlk->portid;
NETLINK_CB(skb).dst_group = dst_group;
NETLINK_CB(skb).creds = siocb->scm->creds;
err = security_netlink_send(sk, skb);
if (err) {
kfree_skb(skb);
goto out;
}
if (unlikely(dst_group)) {
atomic_inc(&skb->users);
netlink_broadcast(sk, skb, dst_portid, dst_group,
GFP_KERNEL);
}
err = netlink_unicast(sk, skb, dst_portid,
msg->msg_flags & MSG_DONTWAIT);
if (err < 0)
goto out;
len += err;
} while (hdr != NULL ||
(!(msg->msg_flags & MSG_DONTWAIT) &&
atomic_read(&nlk->tx_ring.pending)));
if (len > 0)
err = len;
out:
mutex_unlock(&nlk->pg_vec_lock);
return err;
}
static void netlink_queue_mmaped_skb(struct sock *sk, struct sk_buff *skb)
{
struct nl_mmap_hdr *hdr;
hdr = netlink_mmap_hdr(skb);
hdr->nm_len = skb->len;
hdr->nm_group = NETLINK_CB(skb).dst_group;
hdr->nm_pid = NETLINK_CB(skb).creds.pid;
hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
netlink_frame_flush_dcache(hdr);
netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
NETLINK_CB(skb).flags |= NETLINK_SKB_DELIVERED;
kfree_skb(skb);
}
static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb)
{
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_ring *ring = &nlk->rx_ring;
struct nl_mmap_hdr *hdr;
spin_lock_bh(&sk->sk_receive_queue.lock);
hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
if (hdr == NULL) {
spin_unlock_bh(&sk->sk_receive_queue.lock);
kfree_skb(skb);
netlink_overrun(sk);
return;
}
netlink_increment_head(ring);
__skb_queue_tail(&sk->sk_receive_queue, skb);
spin_unlock_bh(&sk->sk_receive_queue.lock);
hdr->nm_len = skb->len;
hdr->nm_group = NETLINK_CB(skb).dst_group;
hdr->nm_pid = NETLINK_CB(skb).creds.pid;
hdr->nm_uid = from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
hdr->nm_gid = from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
netlink_set_status(hdr, NL_MMAP_STATUS_COPY);
}
#else /* CONFIG_NETLINK_MMAP */
#define netlink_skb_is_mmaped(skb) false
#define netlink_rx_is_mmaped(sk) false
#define netlink_tx_is_mmaped(sk) false
#define netlink_mmap sock_no_mmap
#define netlink_poll datagram_poll
#define netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group, siocb) 0
#endif /* CONFIG_NETLINK_MMAP */
static void netlink_skb_destructor(struct sk_buff *skb)
{
#ifdef CONFIG_NETLINK_MMAP
struct nl_mmap_hdr *hdr;
struct netlink_ring *ring;
struct sock *sk;
/* If a packet from the kernel to userspace was freed because of an
* error without being delivered to userspace, the kernel must reset
* the status. In the direction userspace to kernel, the status is
* always reset here after the packet was processed and freed.
*/
if (netlink_skb_is_mmaped(skb)) {
hdr = netlink_mmap_hdr(skb);
sk = NETLINK_CB(skb).sk;
if (NETLINK_CB(skb).flags & NETLINK_SKB_TX) {
netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
ring = &nlk_sk(sk)->tx_ring;
} else {
if (!(NETLINK_CB(skb).flags & NETLINK_SKB_DELIVERED)) {
hdr->nm_len = 0;
netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
}
ring = &nlk_sk(sk)->rx_ring;
}
WARN_ON(atomic_read(&ring->pending) == 0);
atomic_dec(&ring->pending);
sock_put(sk);
skb->head = NULL;
}
#endif
if (is_vmalloc_addr(skb->head)) {
if (!skb->cloned ||
!atomic_dec_return(&(skb_shinfo(skb)->dataref)))
vfree(skb->head);
skb->head = NULL;
}
if (skb->sk != NULL)
sock_rfree(skb);
}
static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
{
WARN_ON(skb->sk != NULL);
skb->sk = sk;
skb->destructor = netlink_skb_destructor;
atomic_add(skb->truesize, &sk->sk_rmem_alloc);
sk_mem_charge(sk, skb->truesize);
}
static void netlink_sock_destruct(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (nlk->cb_running) {
if (nlk->cb.done)
nlk->cb.done(&nlk->cb);
module_put(nlk->cb.module);
kfree_skb(nlk->cb.skb);
}
skb_queue_purge(&sk->sk_receive_queue);
#ifdef CONFIG_NETLINK_MMAP
if (1) {
struct nl_mmap_req req;
memset(&req, 0, sizeof(req));
if (nlk->rx_ring.pg_vec)
netlink_set_ring(sk, &req, true, false);
memset(&req, 0, sizeof(req));
if (nlk->tx_ring.pg_vec)
netlink_set_ring(sk, &req, true, true);
}
#endif /* CONFIG_NETLINK_MMAP */
if (!sock_flag(sk, SOCK_DEAD)) {
printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
return;
}
WARN_ON(atomic_read(&sk->sk_rmem_alloc));
WARN_ON(atomic_read(&sk->sk_wmem_alloc));
WARN_ON(nlk_sk(sk)->groups);
}
/* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
* SMP. Look, when several writers sleep and reader wakes them up, all but one
* immediately hit write lock and grab all the cpus. Exclusive sleep solves
* this, _but_ remember, it adds useless work on UP machines.
*/
void netlink_table_grab(void)
__acquires(nl_table_lock)
{
might_sleep();
write_lock_irq(&nl_table_lock);
if (atomic_read(&nl_table_users)) {
DECLARE_WAITQUEUE(wait, current);
add_wait_queue_exclusive(&nl_table_wait, &wait);
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (atomic_read(&nl_table_users) == 0)
break;
write_unlock_irq(&nl_table_lock);
schedule();
write_lock_irq(&nl_table_lock);
}
__set_current_state(TASK_RUNNING);
remove_wait_queue(&nl_table_wait, &wait);
}
}
void netlink_table_ungrab(void)
__releases(nl_table_lock)
{
write_unlock_irq(&nl_table_lock);
wake_up(&nl_table_wait);
}
static inline void
netlink_lock_table(void)
{
/* read_lock() synchronizes us to netlink_table_grab */
read_lock(&nl_table_lock);
atomic_inc(&nl_table_users);
read_unlock(&nl_table_lock);
}
static inline void
netlink_unlock_table(void)
{
if (atomic_dec_and_test(&nl_table_users))
wake_up(&nl_table_wait);
}
static bool netlink_compare(struct net *net, struct sock *sk)
{
return net_eq(sock_net(sk), net);
}
static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
{
struct netlink_table *table = &nl_table[protocol];
struct nl_portid_hash *hash = &table->hash;
struct hlist_head *head;
struct sock *sk;
read_lock(&nl_table_lock);
head = nl_portid_hashfn(hash, portid);
sk_for_each(sk, head) {
if (table->compare(net, sk) &&
(nlk_sk(sk)->portid == portid)) {
sock_hold(sk);
goto found;
}
}
sk = NULL;
found:
read_unlock(&nl_table_lock);
return sk;
}
static struct hlist_head *nl_portid_hash_zalloc(size_t size)
{
if (size <= PAGE_SIZE)
return kzalloc(size, GFP_ATOMIC);
else
return (struct hlist_head *)
__get_free_pages(GFP_ATOMIC | __GFP_ZERO,
get_order(size));
}
static void nl_portid_hash_free(struct hlist_head *table, size_t size)
{
if (size <= PAGE_SIZE)
kfree(table);
else
free_pages((unsigned long)table, get_order(size));
}
static int nl_portid_hash_rehash(struct nl_portid_hash *hash, int grow)
{
unsigned int omask, mask, shift;
size_t osize, size;
struct hlist_head *otable, *table;
int i;
omask = mask = hash->mask;
osize = size = (mask + 1) * sizeof(*table);
shift = hash->shift;
if (grow) {
if (++shift > hash->max_shift)
return 0;
mask = mask * 2 + 1;
size *= 2;
}
table = nl_portid_hash_zalloc(size);
if (!table)
return 0;
otable = hash->table;
hash->table = table;
hash->mask = mask;
hash->shift = shift;
get_random_bytes(&hash->rnd, sizeof(hash->rnd));
for (i = 0; i <= omask; i++) {
struct sock *sk;
struct hlist_node *tmp;
sk_for_each_safe(sk, tmp, &otable[i])
__sk_add_node(sk, nl_portid_hashfn(hash, nlk_sk(sk)->portid));
}
nl_portid_hash_free(otable, osize);
hash->rehash_time = jiffies + 10 * 60 * HZ;
return 1;
}
static inline int nl_portid_hash_dilute(struct nl_portid_hash *hash, int len)
{
int avg = hash->entries >> hash->shift;
if (unlikely(avg > 1) && nl_portid_hash_rehash(hash, 1))
return 1;
if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
nl_portid_hash_rehash(hash, 0);
return 1;
}
return 0;
}
static const struct proto_ops netlink_ops;
static void
netlink_update_listeners(struct sock *sk)
{
struct netlink_table *tbl = &nl_table[sk->sk_protocol];
unsigned long mask;
unsigned int i;
struct listeners *listeners;
listeners = nl_deref_protected(tbl->listeners);
if (!listeners)
return;
for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
mask = 0;
sk_for_each_bound(sk, &tbl->mc_list) {
if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
mask |= nlk_sk(sk)->groups[i];
}
listeners->masks[i] = mask;
}
/* this function is only called with the netlink table "grabbed", which
* makes sure updates are visible before bind or setsockopt return. */
}
static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
{
struct netlink_table *table = &nl_table[sk->sk_protocol];
struct nl_portid_hash *hash = &table->hash;
struct hlist_head *head;
int err = -EADDRINUSE;
struct sock *osk;
int len;
netlink_table_grab();
head = nl_portid_hashfn(hash, portid);
len = 0;
sk_for_each(osk, head) {
if (table->compare(net, osk) &&
(nlk_sk(osk)->portid == portid))
break;
len++;
}
if (osk)
goto err;
err = -EBUSY;
if (nlk_sk(sk)->portid)
goto err;
err = -ENOMEM;
if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
goto err;
if (len && nl_portid_hash_dilute(hash, len))
head = nl_portid_hashfn(hash, portid);
hash->entries++;
nlk_sk(sk)->portid = portid;
sk_add_node(sk, head);
err = 0;
err:
netlink_table_ungrab();
return err;
}
static void netlink_remove(struct sock *sk)
{
netlink_table_grab();
if (sk_del_node_init(sk))
nl_table[sk->sk_protocol].hash.entries--;
if (nlk_sk(sk)->subscriptions)
__sk_del_bind_node(sk);
netlink_table_ungrab();
}
static struct proto netlink_proto = {
.name = "NETLINK",
.owner = THIS_MODULE,
.obj_size = sizeof(struct netlink_sock),
};
static int __netlink_create(struct net *net, struct socket *sock,
struct mutex *cb_mutex, int protocol)
{
struct sock *sk;
struct netlink_sock *nlk;
sock->ops = &netlink_ops;
sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto);
if (!sk)
return -ENOMEM;
sock_init_data(sock, sk);
nlk = nlk_sk(sk);
if (cb_mutex) {
nlk->cb_mutex = cb_mutex;
} else {
nlk->cb_mutex = &nlk->cb_def_mutex;
mutex_init(nlk->cb_mutex);
}
init_waitqueue_head(&nlk->wait);
#ifdef CONFIG_NETLINK_MMAP
mutex_init(&nlk->pg_vec_lock);
#endif
sk->sk_destruct = netlink_sock_destruct;
sk->sk_protocol = protocol;
return 0;
}
static int netlink_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
struct module *module = NULL;
struct mutex *cb_mutex;
struct netlink_sock *nlk;
void (*bind)(int group);
int err = 0;
sock->state = SS_UNCONNECTED;
if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
return -ESOCKTNOSUPPORT;
if (protocol < 0 || protocol >= MAX_LINKS)
return -EPROTONOSUPPORT;
netlink_lock_table();
#ifdef CONFIG_MODULES
if (!nl_table[protocol].registered) {
netlink_unlock_table();
request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
netlink_lock_table();
}
#endif
if (nl_table[protocol].registered &&
try_module_get(nl_table[protocol].module))
module = nl_table[protocol].module;
else
err = -EPROTONOSUPPORT;
cb_mutex = nl_table[protocol].cb_mutex;
bind = nl_table[protocol].bind;
netlink_unlock_table();
if (err < 0)
goto out;
err = __netlink_create(net, sock, cb_mutex, protocol);
if (err < 0)
goto out_module;
local_bh_disable();
sock_prot_inuse_add(net, &netlink_proto, 1);
local_bh_enable();
nlk = nlk_sk(sock->sk);
nlk->module = module;
nlk->netlink_bind = bind;
out:
return err;
out_module:
module_put(module);
goto out;
}
static int netlink_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk;
if (!sk)
return 0;
netlink_remove(sk);
sock_orphan(sk);
nlk = nlk_sk(sk);
/*
* OK. Socket is unlinked, any packets that arrive now
* will be purged.
*/
sock->sk = NULL;
wake_up_interruptible_all(&nlk->wait);
skb_queue_purge(&sk->sk_write_queue);
if (nlk->portid) {
struct netlink_notify n = {
.net = sock_net(sk),
.protocol = sk->sk_protocol,
.portid = nlk->portid,
};
atomic_notifier_call_chain(&netlink_chain,
NETLINK_URELEASE, &n);
}
module_put(nlk->module);
netlink_table_grab();
if (netlink_is_kernel(sk)) {
BUG_ON(nl_table[sk->sk_protocol].registered == 0);
if (--nl_table[sk->sk_protocol].registered == 0) {
struct listeners *old;
old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
kfree_rcu(old, rcu);
nl_table[sk->sk_protocol].module = NULL;
nl_table[sk->sk_protocol].bind = NULL;
nl_table[sk->sk_protocol].flags = 0;
nl_table[sk->sk_protocol].registered = 0;
}
} else if (nlk->subscriptions) {
netlink_update_listeners(sk);
}
netlink_table_ungrab();
kfree(nlk->groups);
nlk->groups = NULL;
local_bh_disable();
sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
local_bh_enable();
sock_put(sk);
return 0;
}
static int netlink_autobind(struct socket *sock)
{
struct sock *sk = sock->sk;
struct net *net = sock_net(sk);
struct netlink_table *table = &nl_table[sk->sk_protocol];
struct nl_portid_hash *hash = &table->hash;
struct hlist_head *head;
struct sock *osk;
s32 portid = task_tgid_vnr(current);
int err;
static s32 rover = -4097;
retry:
cond_resched();
netlink_table_grab();
head = nl_portid_hashfn(hash, portid);
sk_for_each(osk, head) {
if (!table->compare(net, osk))
continue;
if (nlk_sk(osk)->portid == portid) {
/* Bind collision, search negative portid values. */
portid = rover--;
if (rover > -4097)
rover = -4097;
netlink_table_ungrab();
goto retry;
}
}
netlink_table_ungrab();
err = netlink_insert(sk, net, portid);
if (err == -EADDRINUSE)
goto retry;
/* If 2 threads race to autobind, that is fine. */
if (err == -EBUSY)
err = 0;
return err;
}
static inline int netlink_capable(const struct socket *sock, unsigned int flag)
{
return (nl_table[sock->sk->sk_protocol].flags & flag) ||
ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
}
static void
netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (nlk->subscriptions && !subscriptions)
__sk_del_bind_node(sk);
else if (!nlk->subscriptions && subscriptions)
sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
nlk->subscriptions = subscriptions;
}
static int netlink_realloc_groups(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
unsigned int groups;
unsigned long *new_groups;
int err = 0;
netlink_table_grab();
groups = nl_table[sk->sk_protocol].groups;
if (!nl_table[sk->sk_protocol].registered) {
err = -ENOENT;
goto out_unlock;
}
if (nlk->ngroups >= groups)
goto out_unlock;
new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
if (new_groups == NULL) {
err = -ENOMEM;
goto out_unlock;
}
memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
nlk->groups = new_groups;
nlk->ngroups = groups;
out_unlock:
netlink_table_ungrab();
return err;
}
static int netlink_bind(struct socket *sock, struct sockaddr *addr,
int addr_len)
{
struct sock *sk = sock->sk;
struct net *net = sock_net(sk);
struct netlink_sock *nlk = nlk_sk(sk);
struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
int err;
if (addr_len < sizeof(struct sockaddr_nl))
return -EINVAL;
if (nladdr->nl_family != AF_NETLINK)
return -EINVAL;
/* Only superuser is allowed to listen multicasts */
if (nladdr->nl_groups) {
if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV))
return -EPERM;
err = netlink_realloc_groups(sk);
if (err)
return err;
}
if (nlk->portid) {
if (nladdr->nl_pid != nlk->portid)
return -EINVAL;
} else {
err = nladdr->nl_pid ?
netlink_insert(sk, net, nladdr->nl_pid) :
netlink_autobind(sock);
if (err)
return err;
}
if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
return 0;
netlink_table_grab();
netlink_update_subscriptions(sk, nlk->subscriptions +
hweight32(nladdr->nl_groups) -
hweight32(nlk->groups[0]));
nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | nladdr->nl_groups;
netlink_update_listeners(sk);
netlink_table_ungrab();
if (nlk->netlink_bind && nlk->groups[0]) {
int i;
for (i=0; i<nlk->ngroups; i++) {
if (test_bit(i, nlk->groups))
nlk->netlink_bind(i);
}
}
return 0;
}
static int netlink_connect(struct socket *sock, struct sockaddr *addr,
int alen, int flags)
{
int err = 0;
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
if (alen < sizeof(addr->sa_family))
return -EINVAL;
if (addr->sa_family == AF_UNSPEC) {
sk->sk_state = NETLINK_UNCONNECTED;
nlk->dst_portid = 0;
nlk->dst_group = 0;
return 0;
}
if (addr->sa_family != AF_NETLINK)
return -EINVAL;
/* Only superuser is allowed to send multicasts */
if (nladdr->nl_groups && !netlink_capable(sock, NL_CFG_F_NONROOT_SEND))
return -EPERM;
if (!nlk->portid)
err = netlink_autobind(sock);
if (err == 0) {
sk->sk_state = NETLINK_CONNECTED;
nlk->dst_portid = nladdr->nl_pid;
nlk->dst_group = ffs(nladdr->nl_groups);
}
return err;
}
static int netlink_getname(struct socket *sock, struct sockaddr *addr,
int *addr_len, int peer)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
nladdr->nl_family = AF_NETLINK;
nladdr->nl_pad = 0;
*addr_len = sizeof(*nladdr);
if (peer) {
nladdr->nl_pid = nlk->dst_portid;
nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
} else {
nladdr->nl_pid = nlk->portid;
nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
}
return 0;
}
static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
{
struct sock *sock;
struct netlink_sock *nlk;
sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
if (!sock)
return ERR_PTR(-ECONNREFUSED);
/* Don't bother queuing skb if kernel socket has no input function */
nlk = nlk_sk(sock);
if (sock->sk_state == NETLINK_CONNECTED &&
nlk->dst_portid != nlk_sk(ssk)->portid) {
sock_put(sock);
return ERR_PTR(-ECONNREFUSED);
}
return sock;
}
struct sock *netlink_getsockbyfilp(struct file *filp)
{
struct inode *inode = file_inode(filp);
struct sock *sock;
if (!S_ISSOCK(inode->i_mode))
return ERR_PTR(-ENOTSOCK);
sock = SOCKET_I(inode)->sk;
if (sock->sk_family != AF_NETLINK)
return ERR_PTR(-EINVAL);
sock_hold(sock);
return sock;
}
static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
int broadcast)
{
struct sk_buff *skb;
void *data;
if (size <= NLMSG_GOODSIZE || broadcast)
return alloc_skb(size, GFP_KERNEL);
size = SKB_DATA_ALIGN(size) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
data = vmalloc(size);
if (data == NULL)
return NULL;
skb = build_skb(data, size);
if (skb == NULL)
vfree(data);
else {
skb->head_frag = 0;
skb->destructor = netlink_skb_destructor;
}
return skb;
}
/*
* Attach a skb to a netlink socket.
* The caller must hold a reference to the destination socket. On error, the
* reference is dropped. The skb is not send to the destination, just all
* all error checks are performed and memory in the queue is reserved.
* Return values:
* < 0: error. skb freed, reference to sock dropped.
* 0: continue
* 1: repeat lookup - reference dropped while waiting for socket memory.
*/
int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
long *timeo, struct sock *ssk)
{
struct netlink_sock *nlk;
nlk = nlk_sk(sk);
if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
test_bit(NETLINK_CONGESTED, &nlk->state)) &&
!netlink_skb_is_mmaped(skb)) {
DECLARE_WAITQUEUE(wait, current);
if (!*timeo) {
if (!ssk || netlink_is_kernel(ssk))
netlink_overrun(sk);
sock_put(sk);
kfree_skb(skb);
return -EAGAIN;
}
__set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&nlk->wait, &wait);
if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
test_bit(NETLINK_CONGESTED, &nlk->state)) &&
!sock_flag(sk, SOCK_DEAD))
*timeo = schedule_timeout(*timeo);
__set_current_state(TASK_RUNNING);
remove_wait_queue(&nlk->wait, &wait);
sock_put(sk);
if (signal_pending(current)) {
kfree_skb(skb);
return sock_intr_errno(*timeo);
}
return 1;
}
netlink_skb_set_owner_r(skb, sk);
return 0;
}
static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
{
int len = skb->len;
netlink_deliver_tap(skb);
#ifdef CONFIG_NETLINK_MMAP
if (netlink_skb_is_mmaped(skb))
netlink_queue_mmaped_skb(sk, skb);
else if (netlink_rx_is_mmaped(sk))
netlink_ring_set_copied(sk, skb);
else
#endif /* CONFIG_NETLINK_MMAP */
skb_queue_tail(&sk->sk_receive_queue, skb);
sk->sk_data_ready(sk, len);
return len;
}
int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
{
int len = __netlink_sendskb(sk, skb);
sock_put(sk);
return len;
}
void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
{
kfree_skb(skb);
sock_put(sk);
}
static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
{
int delta;
WARN_ON(skb->sk != NULL);
if (netlink_skb_is_mmaped(skb))
return skb;
delta = skb->end - skb->tail;
if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
return skb;
if (skb_shared(skb)) {
struct sk_buff *nskb = skb_clone(skb, allocation);
if (!nskb)
return skb;
consume_skb(skb);
skb = nskb;
}
if (!pskb_expand_head(skb, 0, -delta, allocation))
skb->truesize -= delta;
return skb;
}
static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
struct sock *ssk)
{
int ret;
struct netlink_sock *nlk = nlk_sk(sk);
ret = -ECONNREFUSED;
if (nlk->netlink_rcv != NULL) {
/* We could do a netlink_deliver_tap(skb) here as well
* but since this is intended for the kernel only, we
* should rather let it stay under the hood.
*/
ret = skb->len;
netlink_skb_set_owner_r(skb, sk);
NETLINK_CB(skb).sk = ssk;
nlk->netlink_rcv(skb);
consume_skb(skb);
} else {
kfree_skb(skb);
}
sock_put(sk);
return ret;
}
int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
u32 portid, int nonblock)
{
struct sock *sk;
int err;
long timeo;
skb = netlink_trim(skb, gfp_any());
timeo = sock_sndtimeo(ssk, nonblock);
retry:
sk = netlink_getsockbyportid(ssk, portid);
if (IS_ERR(sk)) {
kfree_skb(skb);
return PTR_ERR(sk);
}
if (netlink_is_kernel(sk))
return netlink_unicast_kernel(sk, skb, ssk);
if (sk_filter(sk, skb)) {
err = skb->len;
kfree_skb(skb);
sock_put(sk);
return err;
}
err = netlink_attachskb(sk, skb, &timeo, ssk);
if (err == 1)
goto retry;
if (err)
return err;
return netlink_sendskb(sk, skb);
}
EXPORT_SYMBOL(netlink_unicast);
struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
u32 dst_portid, gfp_t gfp_mask)
{
#ifdef CONFIG_NETLINK_MMAP
struct sock *sk = NULL;
struct sk_buff *skb;
struct netlink_ring *ring;
struct nl_mmap_hdr *hdr;
unsigned int maxlen;
sk = netlink_getsockbyportid(ssk, dst_portid);
if (IS_ERR(sk))
goto out;
ring = &nlk_sk(sk)->rx_ring;
/* fast-path without atomic ops for common case: non-mmaped receiver */
if (ring->pg_vec == NULL)
goto out_put;
skb = alloc_skb_head(gfp_mask);
if (skb == NULL)
goto err1;
spin_lock_bh(&sk->sk_receive_queue.lock);
/* check again under lock */
if (ring->pg_vec == NULL)
goto out_free;
maxlen = ring->frame_size - NL_MMAP_HDRLEN;
if (maxlen < size)
goto out_free;
netlink_forward_ring(ring);
hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED);
if (hdr == NULL)
goto err2;
netlink_ring_setup_skb(skb, sk, ring, hdr);
netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
atomic_inc(&ring->pending);
netlink_increment_head(ring);
spin_unlock_bh(&sk->sk_receive_queue.lock);
return skb;
err2:
kfree_skb(skb);
spin_unlock_bh(&sk->sk_receive_queue.lock);
netlink_overrun(sk);
err1:
sock_put(sk);
return NULL;
out_free:
kfree_skb(skb);
spin_unlock_bh(&sk->sk_receive_queue.lock);
out_put:
sock_put(sk);
out:
#endif
return alloc_skb(size, gfp_mask);
}
EXPORT_SYMBOL_GPL(netlink_alloc_skb);
int netlink_has_listeners(struct sock *sk, unsigned int group)
{
int res = 0;
struct listeners *listeners;
BUG_ON(!netlink_is_kernel(sk));
rcu_read_lock();
listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
res = test_bit(group - 1, listeners->masks);
rcu_read_unlock();
return res;
}
EXPORT_SYMBOL_GPL(netlink_has_listeners);
static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
!test_bit(NETLINK_CONGESTED, &nlk->state)) {
netlink_skb_set_owner_r(skb, sk);
__netlink_sendskb(sk, skb);
return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
}
return -1;
}
struct netlink_broadcast_data {
struct sock *exclude_sk;
struct net *net;
u32 portid;
u32 group;
int failure;
int delivery_failure;
int congested;
int delivered;
gfp_t allocation;
struct sk_buff *skb, *skb2;
int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
void *tx_data;
};
static int do_one_broadcast(struct sock *sk,
struct netlink_broadcast_data *p)
{
struct netlink_sock *nlk = nlk_sk(sk);
int val;
if (p->exclude_sk == sk)
goto out;
if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
!test_bit(p->group - 1, nlk->groups))
goto out;
if (!net_eq(sock_net(sk), p->net))
goto out;
if (p->failure) {
netlink_overrun(sk);
goto out;
}
sock_hold(sk);
if (p->skb2 == NULL) {
if (skb_shared(p->skb)) {
p->skb2 = skb_clone(p->skb, p->allocation);
} else {
p->skb2 = skb_get(p->skb);
/*
* skb ownership may have been set when
* delivered to a previous socket.
*/
skb_orphan(p->skb2);
}
}
if (p->skb2 == NULL) {
netlink_overrun(sk);
/* Clone failed. Notify ALL listeners. */
p->failure = 1;
if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
p->delivery_failure = 1;
} else if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
kfree_skb(p->skb2);
p->skb2 = NULL;
} else if (sk_filter(sk, p->skb2)) {
kfree_skb(p->skb2);
p->skb2 = NULL;
} else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
netlink_overrun(sk);
if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
p->delivery_failure = 1;
} else {
p->congested |= val;
p->delivered = 1;
p->skb2 = NULL;
}
sock_put(sk);
out:
return 0;
}
int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
u32 group, gfp_t allocation,
int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
void *filter_data)
{
struct net *net = sock_net(ssk);
struct netlink_broadcast_data info;
struct sock *sk;
skb = netlink_trim(skb, allocation);
info.exclude_sk = ssk;
info.net = net;
info.portid = portid;
info.group = group;
info.failure = 0;
info.delivery_failure = 0;
info.congested = 0;
info.delivered = 0;
info.allocation = allocation;
info.skb = skb;
info.skb2 = NULL;
info.tx_filter = filter;
info.tx_data = filter_data;
/* While we sleep in clone, do not allow to change socket list */
netlink_lock_table();
sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
do_one_broadcast(sk, &info);
consume_skb(skb);
netlink_unlock_table();
if (info.delivery_failure) {
kfree_skb(info.skb2);
return -ENOBUFS;
}
consume_skb(info.skb2);
if (info.delivered) {
if (info.congested && (allocation & __GFP_WAIT))
yield();
return 0;
}
return -ESRCH;
}
EXPORT_SYMBOL(netlink_broadcast_filtered);
int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
u32 group, gfp_t allocation)
{
return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
NULL, NULL);
}
EXPORT_SYMBOL(netlink_broadcast);
struct netlink_set_err_data {
struct sock *exclude_sk;
u32 portid;
u32 group;
int code;
};
static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
{
struct netlink_sock *nlk = nlk_sk(sk);
int ret = 0;
if (sk == p->exclude_sk)
goto out;
if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
goto out;
if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
!test_bit(p->group - 1, nlk->groups))
goto out;
if (p->code == ENOBUFS && nlk->flags & NETLINK_RECV_NO_ENOBUFS) {
ret = 1;
goto out;
}
sk->sk_err = p->code;
sk->sk_error_report(sk);
out:
return ret;
}
/**
* netlink_set_err - report error to broadcast listeners
* @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
* @portid: the PORTID of a process that we want to skip (if any)
* @groups: the broadcast group that will notice the error
* @code: error code, must be negative (as usual in kernelspace)
*
* This function returns the number of broadcast listeners that have set the
* NETLINK_RECV_NO_ENOBUFS socket option.
*/
int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
{
struct netlink_set_err_data info;
struct sock *sk;
int ret = 0;
info.exclude_sk = ssk;
info.portid = portid;
info.group = group;
/* sk->sk_err wants a positive error value */
info.code = -code;
read_lock(&nl_table_lock);
sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
ret += do_one_set_err(sk, &info);
read_unlock(&nl_table_lock);
return ret;
}
EXPORT_SYMBOL(netlink_set_err);
/* must be called with netlink table grabbed */
static void netlink_update_socket_mc(struct netlink_sock *nlk,
unsigned int group,
int is_new)
{
int old, new = !!is_new, subscriptions;
old = test_bit(group - 1, nlk->groups);
subscriptions = nlk->subscriptions - old + new;
if (new)
__set_bit(group - 1, nlk->groups);
else
__clear_bit(group - 1, nlk->groups);
netlink_update_subscriptions(&nlk->sk, subscriptions);
netlink_update_listeners(&nlk->sk);
}
static int netlink_setsockopt(struct socket *sock, int level, int optname,
char __user *optval, unsigned int optlen)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
unsigned int val = 0;
int err;
if (level != SOL_NETLINK)
return -ENOPROTOOPT;
if (optname != NETLINK_RX_RING && optname != NETLINK_TX_RING &&
optlen >= sizeof(int) &&
get_user(val, (unsigned int __user *)optval))
return -EFAULT;
switch (optname) {
case NETLINK_PKTINFO:
if (val)
nlk->flags |= NETLINK_RECV_PKTINFO;
else
nlk->flags &= ~NETLINK_RECV_PKTINFO;
err = 0;
break;
case NETLINK_ADD_MEMBERSHIP:
case NETLINK_DROP_MEMBERSHIP: {
if (!netlink_capable(sock, NL_CFG_F_NONROOT_RECV))
return -EPERM;
err = netlink_realloc_groups(sk);
if (err)
return err;
if (!val || val - 1 >= nlk->ngroups)
return -EINVAL;
netlink_table_grab();
netlink_update_socket_mc(nlk, val,
optname == NETLINK_ADD_MEMBERSHIP);
netlink_table_ungrab();
if (nlk->netlink_bind)
nlk->netlink_bind(val);
err = 0;
break;
}
case NETLINK_BROADCAST_ERROR:
if (val)
nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
else
nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
err = 0;
break;
case NETLINK_NO_ENOBUFS:
if (val) {
nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
clear_bit(NETLINK_CONGESTED, &nlk->state);
wake_up_interruptible(&nlk->wait);
} else {
nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
}
err = 0;
break;
#ifdef CONFIG_NETLINK_MMAP
case NETLINK_RX_RING:
case NETLINK_TX_RING: {
struct nl_mmap_req req;
/* Rings might consume more memory than queue limits, require
* CAP_NET_ADMIN.
*/
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (optlen < sizeof(req))
return -EINVAL;
if (copy_from_user(&req, optval, sizeof(req)))
return -EFAULT;
err = netlink_set_ring(sk, &req, false,
optname == NETLINK_TX_RING);
break;
}
#endif /* CONFIG_NETLINK_MMAP */
default:
err = -ENOPROTOOPT;
}
return err;
}
static int netlink_getsockopt(struct socket *sock, int level, int optname,
char __user *optval, int __user *optlen)
{
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
int len, val, err;
if (level != SOL_NETLINK)
return -ENOPROTOOPT;
if (get_user(len, optlen))
return -EFAULT;
if (len < 0)
return -EINVAL;
switch (optname) {
case NETLINK_PKTINFO:
if (len < sizeof(int))
return -EINVAL;
len = sizeof(int);
val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;
if (put_user(len, optlen) ||
put_user(val, optval))
return -EFAULT;
err = 0;
break;
case NETLINK_BROADCAST_ERROR:
if (len < sizeof(int))
return -EINVAL;
len = sizeof(int);
val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
if (put_user(len, optlen) ||
put_user(val, optval))
return -EFAULT;
err = 0;
break;
case NETLINK_NO_ENOBUFS:
if (len < sizeof(int))
return -EINVAL;
len = sizeof(int);
val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
if (put_user(len, optlen) ||
put_user(val, optval))
return -EFAULT;
err = 0;
break;
default:
err = -ENOPROTOOPT;
}
return err;
}
static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
{
struct nl_pktinfo info;
info.group = NETLINK_CB(skb).dst_group;
put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
}
static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
struct msghdr *msg, size_t len)
{
struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
struct sockaddr_nl *addr = msg->msg_name;
u32 dst_portid;
u32 dst_group;
struct sk_buff *skb;
int err;
struct scm_cookie scm;
if (msg->msg_flags&MSG_OOB)
return -EOPNOTSUPP;
if (NULL == siocb->scm)
siocb->scm = &scm;
err = scm_send(sock, msg, siocb->scm, true);
if (err < 0)
return err;
if (msg->msg_namelen) {
err = -EINVAL;
if (addr->nl_family != AF_NETLINK)
goto out;
dst_portid = addr->nl_pid;
dst_group = ffs(addr->nl_groups);
err = -EPERM;
if ((dst_group || dst_portid) &&
!netlink_capable(sock, NL_CFG_F_NONROOT_SEND))
goto out;
} else {
dst_portid = nlk->dst_portid;
dst_group = nlk->dst_group;
}
if (!nlk->portid) {
err = netlink_autobind(sock);
if (err)
goto out;
}
if (netlink_tx_is_mmaped(sk) &&
msg->msg_iov->iov_base == NULL) {
err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
siocb);
goto out;
}
err = -EMSGSIZE;
if (len > sk->sk_sndbuf - 32)
goto out;
err = -ENOBUFS;
skb = netlink_alloc_large_skb(len, dst_group);
if (skb == NULL)
goto out;
NETLINK_CB(skb).portid = nlk->portid;
NETLINK_CB(skb).dst_group = dst_group;
NETLINK_CB(skb).creds = siocb->scm->creds;
err = -EFAULT;
if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
kfree_skb(skb);
goto out;
}
err = security_netlink_send(sk, skb);
if (err) {
kfree_skb(skb);
goto out;
}
if (dst_group) {
atomic_inc(&skb->users);
netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
}
err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
out:
scm_destroy(siocb->scm);
return err;
}
static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock,
struct msghdr *msg, size_t len,
int flags)
{
struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
struct scm_cookie scm;
struct sock *sk = sock->sk;
struct netlink_sock *nlk = nlk_sk(sk);
int noblock = flags&MSG_DONTWAIT;
size_t copied;
struct sk_buff *skb, *data_skb;
int err, ret;
if (flags&MSG_OOB)
return -EOPNOTSUPP;
copied = 0;
skb = skb_recv_datagram(sk, flags, noblock, &err);
if (skb == NULL)
goto out;
data_skb = skb;
#ifdef CONFIG_COMPAT_NETLINK_MESSAGES
if (unlikely(skb_shinfo(skb)->frag_list)) {
/*
* If this skb has a frag_list, then here that means that we
* will have to use the frag_list skb's data for compat tasks
* and the regular skb's data for normal (non-compat) tasks.
*
* If we need to send the compat skb, assign it to the
* 'data_skb' variable so that it will be used below for data
* copying. We keep 'skb' for everything else, including
* freeing both later.
*/
if (flags & MSG_CMSG_COMPAT)
data_skb = skb_shinfo(skb)->frag_list;
}
#endif
msg->msg_namelen = 0;
copied = data_skb->len;
if (len < copied) {
msg->msg_flags |= MSG_TRUNC;
copied = len;
}
skb_reset_transport_header(data_skb);
err = skb_copy_datagram_iovec(data_skb, 0, msg->msg_iov, copied);
if (msg->msg_name) {
struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name;
addr->nl_family = AF_NETLINK;
addr->nl_pad = 0;
addr->nl_pid = NETLINK_CB(skb).portid;
addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
msg->msg_namelen = sizeof(*addr);
}
if (nlk->flags & NETLINK_RECV_PKTINFO)
netlink_cmsg_recv_pktinfo(msg, skb);
if (NULL == siocb->scm) {
memset(&scm, 0, sizeof(scm));
siocb->scm = &scm;
}
siocb->scm->creds = *NETLINK_CREDS(skb);
if (flags & MSG_TRUNC)
copied = data_skb->len;
skb_free_datagram(sk, skb);
if (nlk->cb_running &&
atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
ret = netlink_dump(sk);
if (ret) {
sk->sk_err = ret;
sk->sk_error_report(sk);
}
}
scm_recv(sock, msg, siocb->scm, flags);
out:
netlink_rcv_wake(sk);
return err ? : copied;
}
static void netlink_data_ready(struct sock *sk, int len)
{
BUG();
}
/*
* We export these functions to other modules. They provide a
* complete set of kernel non-blocking support for message
* queueing.
*/
struct sock *
__netlink_kernel_create(struct net *net, int unit, struct module *module,
struct netlink_kernel_cfg *cfg)
{
struct socket *sock;
struct sock *sk;
struct netlink_sock *nlk;
struct listeners *listeners = NULL;
struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
unsigned int groups;
BUG_ON(!nl_table);
if (unit < 0 || unit >= MAX_LINKS)
return NULL;
if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
return NULL;
/*
* We have to just have a reference on the net from sk, but don't
* get_net it. Besides, we cannot get and then put the net here.
* So we create one inside init_net and the move it to net.
*/
if (__netlink_create(&init_net, sock, cb_mutex, unit) < 0)
goto out_sock_release_nosk;
sk = sock->sk;
sk_change_net(sk, net);
if (!cfg || cfg->groups < 32)
groups = 32;
else
groups = cfg->groups;
listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
if (!listeners)
goto out_sock_release;
sk->sk_data_ready = netlink_data_ready;
if (cfg && cfg->input)
nlk_sk(sk)->netlink_rcv = cfg->input;
if (netlink_insert(sk, net, 0))
goto out_sock_release;
nlk = nlk_sk(sk);
nlk->flags |= NETLINK_KERNEL_SOCKET;
netlink_table_grab();
if (!nl_table[unit].registered) {
nl_table[unit].groups = groups;
rcu_assign_pointer(nl_table[unit].listeners, listeners);
nl_table[unit].cb_mutex = cb_mutex;
nl_table[unit].module = module;
if (cfg) {
nl_table[unit].bind = cfg->bind;
nl_table[unit].flags = cfg->flags;
if (cfg->compare)
nl_table[unit].compare = cfg->compare;
}
nl_table[unit].registered = 1;
} else {
kfree(listeners);
nl_table[unit].registered++;
}
netlink_table_ungrab();
return sk;
out_sock_release:
kfree(listeners);
netlink_kernel_release(sk);
return NULL;
out_sock_release_nosk:
sock_release(sock);
return NULL;
}
EXPORT_SYMBOL(__netlink_kernel_create);
void
netlink_kernel_release(struct sock *sk)
{
sk_release_kernel(sk);
}
EXPORT_SYMBOL(netlink_kernel_release);
int __netlink_change_ngroups(struct sock *sk, unsigned int groups)
{
struct listeners *new, *old;
struct netlink_table *tbl = &nl_table[sk->sk_protocol];
if (groups < 32)
groups = 32;
if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) {
new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC);
if (!new)
return -ENOMEM;
old = nl_deref_protected(tbl->listeners);
memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups));
rcu_assign_pointer(tbl->listeners, new);
kfree_rcu(old, rcu);
}
tbl->groups = groups;
return 0;
}
/**
* netlink_change_ngroups - change number of multicast groups
*
* This changes the number of multicast groups that are available
* on a certain netlink family. Note that it is not possible to
* change the number of groups to below 32. Also note that it does
* not implicitly call netlink_clear_multicast_users() when the
* number of groups is reduced.
*
* @sk: The kernel netlink socket, as returned by netlink_kernel_create().
* @groups: The new number of groups.
*/
int netlink_change_ngroups(struct sock *sk, unsigned int groups)
{
int err;
netlink_table_grab();
err = __netlink_change_ngroups(sk, groups);
netlink_table_ungrab();
return err;
}
void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
{
struct sock *sk;
struct netlink_table *tbl = &nl_table[ksk->sk_protocol];
sk_for_each_bound(sk, &tbl->mc_list)
netlink_update_socket_mc(nlk_sk(sk), group, 0);
}
/**
* netlink_clear_multicast_users - kick off multicast listeners
*
* This function removes all listeners from the given group.
* @ksk: The kernel netlink socket, as returned by
* netlink_kernel_create().
* @group: The multicast group to clear.
*/
void netlink_clear_multicast_users(struct sock *ksk, unsigned int group)
{
netlink_table_grab();
__netlink_clear_multicast_users(ksk, group);
netlink_table_ungrab();
}
struct nlmsghdr *
__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags)
{
struct nlmsghdr *nlh;
int size = nlmsg_msg_size(len);
nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
nlh->nlmsg_type = type;
nlh->nlmsg_len = size;
nlh->nlmsg_flags = flags;
nlh->nlmsg_pid = portid;
nlh->nlmsg_seq = seq;
if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0)
memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size);
return nlh;
}
EXPORT_SYMBOL(__nlmsg_put);
/*
* It looks a bit ugly.
* It would be better to create kernel thread.
*/
static int netlink_dump(struct sock *sk)
{
struct netlink_sock *nlk = nlk_sk(sk);
struct netlink_callback *cb;
struct sk_buff *skb = NULL;
struct nlmsghdr *nlh;
int len, err = -ENOBUFS;
int alloc_size;
mutex_lock(nlk->cb_mutex);
if (!nlk->cb_running) {
err = -EINVAL;
goto errout_skb;
}
cb = &nlk->cb;
alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE);
if (!netlink_rx_is_mmaped(sk) &&
atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
goto errout_skb;
skb = netlink_alloc_skb(sk, alloc_size, nlk->portid, GFP_KERNEL);
if (!skb)
goto errout_skb;
netlink_skb_set_owner_r(skb, sk);
len = cb->dump(skb, cb);
if (len > 0) {
mutex_unlock(nlk->cb_mutex);
if (sk_filter(sk, skb))
kfree_skb(skb);
else
__netlink_sendskb(sk, skb);
return 0;
}
nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(len), NLM_F_MULTI);
if (!nlh)
goto errout_skb;
nl_dump_check_consistent(cb, nlh);
memcpy(nlmsg_data(nlh), &len, sizeof(len));
if (sk_filter(sk, skb))
kfree_skb(skb);
else
__netlink_sendskb(sk, skb);
if (cb->done)
cb->done(cb);
nlk->cb_running = false;
mutex_unlock(nlk->cb_mutex);
module_put(cb->module);
consume_skb(cb->skb);
return 0;
errout_skb:
mutex_unlock(nlk->cb_mutex);
kfree_skb(skb);
return err;
}
int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
const struct nlmsghdr *nlh,
struct netlink_dump_control *control)
{
struct netlink_callback *cb;
struct sock *sk;
struct netlink_sock *nlk;
int ret;
/* Memory mapped dump requests need to be copied to avoid looping
* on the pending state in netlink_mmap_sendmsg() while the CB hold
* a reference to the skb.
*/
if (netlink_skb_is_mmaped(skb)) {
skb = skb_copy(skb, GFP_KERNEL);
if (skb == NULL)
return -ENOBUFS;
} else
atomic_inc(&skb->users);
sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid);
if (sk == NULL) {
ret = -ECONNREFUSED;
goto error_free;
}
nlk = nlk_sk(sk);
mutex_lock(nlk->cb_mutex);
/* A dump is in progress... */
if (nlk->cb_running) {
ret = -EBUSY;
goto error_unlock;
}
/* add reference of module which cb->dump belongs to */
if (!try_module_get(control->module)) {
ret = -EPROTONOSUPPORT;
goto error_unlock;
}
cb = &nlk->cb;
memset(cb, 0, sizeof(*cb));
cb->dump = control->dump;
cb->done = control->done;
cb->nlh = nlh;
cb->data = control->data;
cb->module = control->module;
cb->min_dump_alloc = control->min_dump_alloc;
cb->skb = skb;
nlk->cb_running = true;
mutex_unlock(nlk->cb_mutex);
ret = netlink_dump(sk);
sock_put(sk);
if (ret)
return ret;
/* We successfully started a dump, by returning -EINTR we
* signal not to send ACK even if it was requested.
*/
return -EINTR;
error_unlock:
sock_put(sk);
mutex_unlock(nlk->cb_mutex);
error_free:
kfree_skb(skb);
return ret;
}
EXPORT_SYMBOL(__netlink_dump_start);
void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
{
struct sk_buff *skb;
struct nlmsghdr *rep;
struct nlmsgerr *errmsg;
size_t payload = sizeof(*errmsg);
/* error messages get the original request appened */
if (err)
payload += nlmsg_len(nlh);
skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload),
NETLINK_CB(in_skb).portid, GFP_KERNEL);
if (!skb) {
struct sock *sk;
sk = netlink_lookup(sock_net(in_skb->sk),
in_skb->sk->sk_protocol,
NETLINK_CB(in_skb).portid);
if (sk) {
sk->sk_err = ENOBUFS;
sk->sk_error_report(sk);
sock_put(sk);
}
return;
}
rep = __nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
NLMSG_ERROR, payload, 0);
errmsg = nlmsg_data(rep);
errmsg->error = err;
memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
}
EXPORT_SYMBOL(netlink_ack);
int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
struct nlmsghdr *))
{
struct nlmsghdr *nlh;
int err;
while (skb->len >= nlmsg_total_size(0)) {
int msglen;
nlh = nlmsg_hdr(skb);
err = 0;
if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len)
return 0;
/* Only requests are handled by the kernel */
if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
goto ack;
/* Skip control messages */
if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
goto ack;
err = cb(skb, nlh);
if (err == -EINTR)
goto skip;
ack:
if (nlh->nlmsg_flags & NLM_F_ACK || err)
netlink_ack(skb, nlh, err);
skip:
msglen = NLMSG_ALIGN(nlh->nlmsg_len);
if (msglen > skb->len)
msglen = skb->len;
skb_pull(skb, msglen);
}
return 0;
}
EXPORT_SYMBOL(netlink_rcv_skb);
/**
* nlmsg_notify - send a notification netlink message
* @sk: netlink socket to use
* @skb: notification message
* @portid: destination netlink portid for reports or 0
* @group: destination multicast group or 0
* @report: 1 to report back, 0 to disable
* @flags: allocation flags
*/
int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
unsigned int group, int report, gfp_t flags)
{
int err = 0;
if (group) {
int exclude_portid = 0;
if (report) {
atomic_inc(&skb->users);
exclude_portid = portid;
}
/* errors reported via destination sk->sk_err, but propagate
* delivery errors if NETLINK_BROADCAST_ERROR flag is set */
err = nlmsg_multicast(sk, skb, exclude_portid, group, flags);
}
if (report) {
int err2;
err2 = nlmsg_unicast(sk, skb, portid);
if (!err || err == -ESRCH)
err = err2;
}
return err;
}
EXPORT_SYMBOL(nlmsg_notify);
#ifdef CONFIG_PROC_FS
struct nl_seq_iter {
struct seq_net_private p;
int link;
int hash_idx;
};
static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
{
struct nl_seq_iter *iter = seq->private;
int i, j;
struct sock *s;
loff_t off = 0;
for (i = 0; i < MAX_LINKS; i++) {
struct nl_portid_hash *hash = &nl_table[i].hash;
for (j = 0; j <= hash->mask; j++) {
sk_for_each(s, &hash->table[j]) {
if (sock_net(s) != seq_file_net(seq))
continue;
if (off == pos) {
iter->link = i;
iter->hash_idx = j;
return s;
}
++off;
}
}
}
return NULL;
}
static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(nl_table_lock)
{
read_lock(&nl_table_lock);
return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}
static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct sock *s;
struct nl_seq_iter *iter;
struct net *net;
int i, j;
++*pos;
if (v == SEQ_START_TOKEN)
return netlink_seq_socket_idx(seq, 0);
net = seq_file_net(seq);
iter = seq->private;
s = v;
do {
s = sk_next(s);
} while (s && !nl_table[s->sk_protocol].compare(net, s));
if (s)
return s;
i = iter->link;
j = iter->hash_idx + 1;
do {
struct nl_portid_hash *hash = &nl_table[i].hash;
for (; j <= hash->mask; j++) {
s = sk_head(&hash->table[j]);
while (s && !nl_table[s->sk_protocol].compare(net, s))
s = sk_next(s);
if (s) {
iter->link = i;
iter->hash_idx = j;
return s;
}
}
j = 0;
} while (++i < MAX_LINKS);
return NULL;
}
static void netlink_seq_stop(struct seq_file *seq, void *v)
__releases(nl_table_lock)
{
read_unlock(&nl_table_lock);
}
static int netlink_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN) {
seq_puts(seq,
"sk Eth Pid Groups "
"Rmem Wmem Dump Locks Drops Inode\n");
} else {
struct sock *s = v;
struct netlink_sock *nlk = nlk_sk(s);
seq_printf(seq, "%pK %-3d %-6u %08x %-8d %-8d %d %-8d %-8d %-8lu\n",
s,
s->sk_protocol,
nlk->portid,
nlk->groups ? (u32)nlk->groups[0] : 0,
sk_rmem_alloc_get(s),
sk_wmem_alloc_get(s),
nlk->cb_running,
atomic_read(&s->sk_refcnt),
atomic_read(&s->sk_drops),
sock_i_ino(s)
);
}
return 0;
}
static const struct seq_operations netlink_seq_ops = {
.start = netlink_seq_start,
.next = netlink_seq_next,
.stop = netlink_seq_stop,
.show = netlink_seq_show,
};
static int netlink_seq_open(struct inode *inode, struct file *file)
{
return seq_open_net(inode, file, &netlink_seq_ops,
sizeof(struct nl_seq_iter));
}
static const struct file_operations netlink_seq_fops = {
.owner = THIS_MODULE,
.open = netlink_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_net,
};
#endif
int netlink_register_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&netlink_chain, nb);
}
EXPORT_SYMBOL(netlink_register_notifier);
int netlink_unregister_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&netlink_chain, nb);
}
EXPORT_SYMBOL(netlink_unregister_notifier);
static const struct proto_ops netlink_ops = {
.family = PF_NETLINK,
.owner = THIS_MODULE,
.release = netlink_release,
.bind = netlink_bind,
.connect = netlink_connect,
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = netlink_getname,
.poll = netlink_poll,
.ioctl = sock_no_ioctl,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.setsockopt = netlink_setsockopt,
.getsockopt = netlink_getsockopt,
.sendmsg = netlink_sendmsg,
.recvmsg = netlink_recvmsg,
.mmap = netlink_mmap,
.sendpage = sock_no_sendpage,
};
static const struct net_proto_family netlink_family_ops = {
.family = PF_NETLINK,
.create = netlink_create,
.owner = THIS_MODULE, /* for consistency 8) */
};
static int __net_init netlink_net_init(struct net *net)
{
#ifdef CONFIG_PROC_FS
if (!proc_create("netlink", 0, net->proc_net, &netlink_seq_fops))
return -ENOMEM;
#endif
return 0;
}
static void __net_exit netlink_net_exit(struct net *net)
{
#ifdef CONFIG_PROC_FS
remove_proc_entry("netlink", net->proc_net);
#endif
}
static void __init netlink_add_usersock_entry(void)
{
struct listeners *listeners;
int groups = 32;
listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
if (!listeners)
panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
netlink_table_grab();
nl_table[NETLINK_USERSOCK].groups = groups;
rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners);
nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
nl_table[NETLINK_USERSOCK].registered = 1;
nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND;
netlink_table_ungrab();
}
static struct pernet_operations __net_initdata netlink_net_ops = {
.init = netlink_net_init,
.exit = netlink_net_exit,
};
static int __init netlink_proto_init(void)
{
int i;
unsigned long limit;
unsigned int order;
int err = proto_register(&netlink_proto, 0);
if (err != 0)
goto out;
BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL);
if (!nl_table)
goto panic;
if (totalram_pages >= (128 * 1024))
limit = totalram_pages >> (21 - PAGE_SHIFT);
else
limit = totalram_pages >> (23 - PAGE_SHIFT);
order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
limit = (1UL << order) / sizeof(struct hlist_head);
order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
for (i = 0; i < MAX_LINKS; i++) {
struct nl_portid_hash *hash = &nl_table[i].hash;
hash->table = nl_portid_hash_zalloc(1 * sizeof(*hash->table));
if (!hash->table) {
while (i-- > 0)
nl_portid_hash_free(nl_table[i].hash.table,
1 * sizeof(*hash->table));
kfree(nl_table);
goto panic;
}
hash->max_shift = order;
hash->shift = 0;
hash->mask = 0;
hash->rehash_time = jiffies;
nl_table[i].compare = netlink_compare;
}
INIT_LIST_HEAD(&netlink_tap_all);
netlink_add_usersock_entry();
sock_register(&netlink_family_ops);
register_pernet_subsys(&netlink_net_ops);
/* The netlink device handler may be needed early. */
rtnetlink_init();
out:
return err;
panic:
panic("netlink_init: Cannot allocate nl_table\n");
}
core_initcall(netlink_proto_init);
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