Commit 097e66c5 authored by Denis V. Lunev's avatar Denis V. Lunev Committed by David S. Miller
Browse files

[NET]: Make AF_UNIX per network namespace safe [v2] 



Because of the global nature of garbage collection, and because of the
cost of per namespace hash tables unix_socket_table has been kept
global.  With a filter added on lookups so we don't see sockets from
the wrong namespace.

Currently I don't fold the namesapce into the hash so multiple
namespaces using the same socket name will be guaranteed a hash
collision.

Changes from v1:
- fixed unix_seq_open

Signed-off-by: default avatarDenis V. Lunev <den@openvz.org>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d12d01d6

net/unix/af_unix.c

+92 −26
Original line number Diff line number Diff line
@@ -270,7 +270,8 @@ static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk) 
	spin_unlock(&unix_table_lock);

}



static struct sock *__unix_find_socket_byname(struct sockaddr_un *sunname,

static struct sock *__unix_find_socket_byname(struct net *net,

					      struct sockaddr_un *sunname,

					      int len, int type, unsigned hash)

{

	struct sock *s;
@@ -279,6 +280,9 @@ static struct sock *__unix_find_socket_byname(struct sockaddr_un *sunname, 
	sk_for_each(s, node, &unix_socket_table[hash ^ type]) {

		struct unix_sock *u = unix_sk(s);



		if (s->sk_net != net)

			continue;



		if (u->addr->len == len &&

		    !memcmp(u->addr->name, sunname, len))

			goto found;
@@ -288,21 +292,22 @@ found: 
	return s;

}



static inline struct sock *unix_find_socket_byname(struct sockaddr_un *sunname,

static inline struct sock *unix_find_socket_byname(struct net *net,

						   struct sockaddr_un *sunname,

						   int len, int type,

						   unsigned hash)

{

	struct sock *s;



	spin_lock(&unix_table_lock);

	s = __unix_find_socket_byname(sunname, len, type, hash);

	s = __unix_find_socket_byname(net, sunname, len, type, hash);

	if (s)

		sock_hold(s);

	spin_unlock(&unix_table_lock);

	return s;

}



static struct sock *unix_find_socket_byinode(struct inode *i)

static struct sock *unix_find_socket_byinode(struct net *net, struct inode *i)

{

	struct sock *s;

	struct hlist_node *node;
@@ -312,6 +317,9 @@ static struct sock *unix_find_socket_byinode(struct inode *i) 
		    &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {

		struct dentry *dentry = unix_sk(s)->dentry;



		if (s->sk_net != net)

			continue;



		if(dentry && dentry->d_inode == i)

		{

			sock_hold(s);
@@ -631,9 +639,6 @@ out: 


static int unix_create(struct net *net, struct socket *sock, int protocol)

{

	if (net != &init_net)

		return -EAFNOSUPPORT;



	if (protocol && protocol != PF_UNIX)

		return -EPROTONOSUPPORT;
@@ -677,6 +682,7 @@ static int unix_release(struct socket *sock) 
static int unix_autobind(struct socket *sock)

{

	struct sock *sk = sock->sk;

	struct net *net = sk->sk_net;

	struct unix_sock *u = unix_sk(sk);

	static u32 ordernum = 1;

	struct unix_address * addr;
@@ -703,7 +709,7 @@ retry: 
	spin_lock(&unix_table_lock);

	ordernum = (ordernum+1)&0xFFFFF;



	if (__unix_find_socket_byname(addr->name, addr->len, sock->type,

	if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,

				      addr->hash)) {

		spin_unlock(&unix_table_lock);

		/* Sanity yield. It is unusual case, but yet... */
@@ -723,7 +729,8 @@ out: mutex_unlock(&u->readlock); 
	return err;

}



static struct sock *unix_find_other(struct sockaddr_un *sunname, int len,

static struct sock *unix_find_other(struct net *net,

				    struct sockaddr_un *sunname, int len,

				    int type, unsigned hash, int *error)

{

	struct sock *u;
@@ -741,7 +748,7 @@ static struct sock *unix_find_other(struct sockaddr_un *sunname, int len, 
		err = -ECONNREFUSED;

		if (!S_ISSOCK(nd.dentry->d_inode->i_mode))

			goto put_fail;

		u=unix_find_socket_byinode(nd.dentry->d_inode);

		u=unix_find_socket_byinode(net, nd.dentry->d_inode);

		if (!u)

			goto put_fail;
@@ -757,7 +764,7 @@ static struct sock *unix_find_other(struct sockaddr_un *sunname, int len, 
		}

	} else {

		err = -ECONNREFUSED;

		u=unix_find_socket_byname(sunname, len, type, hash);

		u=unix_find_socket_byname(net, sunname, len, type, hash);

		if (u) {

			struct dentry *dentry;

			dentry = unix_sk(u)->dentry;
@@ -779,6 +786,7 @@ fail: 
static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)

{

	struct sock *sk = sock->sk;

	struct net *net = sk->sk_net;

	struct unix_sock *u = unix_sk(sk);

	struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;

	struct dentry * dentry = NULL;
@@ -853,7 +861,7 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 


	if (!sunaddr->sun_path[0]) {

		err = -EADDRINUSE;

		if (__unix_find_socket_byname(sunaddr, addr_len,

		if (__unix_find_socket_byname(net, sunaddr, addr_len,

					      sk->sk_type, hash)) {

			unix_release_addr(addr);

			goto out_unlock;
@@ -919,6 +927,7 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, 
			      int alen, int flags)

{

	struct sock *sk = sock->sk;

	struct net *net = sk->sk_net;

	struct sockaddr_un *sunaddr=(struct sockaddr_un*)addr;

	struct sock *other;

	unsigned hash;
@@ -935,7 +944,7 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, 
			goto out;



restart:

		other=unix_find_other(sunaddr, alen, sock->type, hash, &err);

		other=unix_find_other(net, sunaddr, alen, sock->type, hash, &err);

		if (!other)

			goto out;
@@ -1015,6 +1024,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 
{

	struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;

	struct sock *sk = sock->sk;

	struct net *net = sk->sk_net;

	struct unix_sock *u = unix_sk(sk), *newu, *otheru;

	struct sock *newsk = NULL;

	struct sock *other = NULL;
@@ -1054,7 +1064,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 


restart:

	/*  Find listening sock. */

	other = unix_find_other(sunaddr, addr_len, sk->sk_type, hash, &err);

	other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);

	if (!other)

		goto out;
@@ -1330,6 +1340,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 
{

	struct sock_iocb *siocb = kiocb_to_siocb(kiocb);

	struct sock *sk = sock->sk;

	struct net *net = sk->sk_net;

	struct unix_sock *u = unix_sk(sk);

	struct sockaddr_un *sunaddr=msg->msg_name;

	struct sock *other = NULL;
@@ -1393,7 +1404,7 @@ restart: 
		if (sunaddr == NULL)

			goto out_free;



		other = unix_find_other(sunaddr, namelen, sk->sk_type,

		other = unix_find_other(net, sunaddr, namelen, sk->sk_type,

					hash, &err);

		if (other==NULL)

			goto out_free;
@@ -2006,12 +2017,18 @@ static unsigned int unix_poll(struct file * file, struct socket *sock, poll_tabl 




#ifdef CONFIG_PROC_FS

static struct sock *unix_seq_idx(int *iter, loff_t pos)

struct unix_iter_state {

	struct net *net;

	int i;

};

static struct sock *unix_seq_idx(struct unix_iter_state *iter, loff_t pos)

{

	loff_t off = 0;

	struct sock *s;



	for (s = first_unix_socket(iter); s; s = next_unix_socket(iter, s)) {

	for (s = first_unix_socket(&iter->i); s; s = next_unix_socket(&iter->i, s)) {

		if (s->sk_net != iter->net)

			continue;

		if (off == pos)

			return s;

		++off;
@@ -2022,17 +2039,24 @@ static struct sock *unix_seq_idx(int *iter, loff_t pos) 


static void *unix_seq_start(struct seq_file *seq, loff_t *pos)

{

	struct unix_iter_state *iter = seq->private;

	spin_lock(&unix_table_lock);

	return *pos ? unix_seq_idx(seq->private, *pos - 1) : ((void *) 1);

	return *pos ? unix_seq_idx(iter, *pos - 1) : ((void *) 1);

}



static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)

{

	struct unix_iter_state *iter = seq->private;

	struct sock *sk = v;

	++*pos;



	if (v == (void *)1)

		return first_unix_socket(seq->private);

	return next_unix_socket(seq->private, v);

		sk = first_unix_socket(&iter->i);

	else

		sk = next_unix_socket(&iter->i, sk);

	while (sk && (sk->sk_net != iter->net))

		sk = next_unix_socket(&iter->i, sk);

	return sk;

}



static void unix_seq_stop(struct seq_file *seq, void *v)
@@ -2094,7 +2118,27 @@ static const struct seq_operations unix_seq_ops = { 


static int unix_seq_open(struct inode *inode, struct file *file)

{

	return seq_open_private(file, &unix_seq_ops, sizeof(int));

	struct unix_iter_state *it;



	it = __seq_open_private(file, &unix_seq_ops,

				sizeof(struct unix_iter_state));

	if (it == NULL)

		return -ENOMEM;



	it->net = get_proc_net(inode);

	if (it->net == NULL) {

		seq_release_private(inode, file);

		return -ENXIO;

	}

	return 0;

}



static int unix_seq_release(struct inode *inode, struct file *file)

{

	struct seq_file *seq = file->private_data;

	struct unix_iter_state *iter = seq->private;

	put_net(iter->net);

	return seq_release_private(inode, file);

}



static const struct file_operations unix_seq_fops = {
@@ -2102,7 +2146,7 @@ static const struct file_operations unix_seq_fops = { 
	.open		= unix_seq_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= seq_release_private,

	.release	= unix_seq_release,

};



#endif
@@ -2113,6 +2157,30 @@ static struct net_proto_family unix_family_ops = { 
	.owner	= THIS_MODULE,

};





static int unix_net_init(struct net *net)

{

	int error = -ENOMEM;



#ifdef CONFIG_PROC_FS

	if (!proc_net_fops_create(net, "unix", 0, &unix_seq_fops))

		goto out;

#endif

	error = 0;

out:

	return 0;

}



static void unix_net_exit(struct net *net)

{

	proc_net_remove(net, "unix");

}



static struct pernet_operations unix_net_ops = {

	.init = unix_net_init,

	.exit = unix_net_exit,

};



static int __init af_unix_init(void)

{

	int rc = -1;
@@ -2128,9 +2196,7 @@ static int __init af_unix_init(void) 
	}



	sock_register(&unix_family_ops);

#ifdef CONFIG_PROC_FS

	proc_net_fops_create(&init_net, "unix", 0, &unix_seq_fops);

#endif

	register_pernet_subsys(&unix_net_ops);

	unix_sysctl_register();

out:

	return rc;
@@ -2140,8 +2206,8 @@ static void __exit af_unix_exit(void) 
{

	sock_unregister(PF_UNIX);

	unix_sysctl_unregister();

	proc_net_remove(&init_net, "unix");

	proto_unregister(&unix_proto);

	unregister_pernet_subsys(&unix_net_ops);

}



module_init(af_unix_init);

CRA Git | Maintained and supported by SUSTech CRA and CCSE