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[NET]: Make AF_UNIX per network namespace safe [v2]
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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: Denis V. Lunev <den@openvz.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Denis V. Lunev authored and David S. Miller committed Jan 28, 2008
1 parent d12d01d commit 097e66c
Showing 1 changed file with 92 additions and 26 deletions.
118 changes: 92 additions & 26 deletions net/unix/af_unix.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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;
Expand All @@ -288,21 +292,22 @@ static struct sock *__unix_find_socket_byname(struct sockaddr_un *sunname,
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;
Expand All @@ -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);
Expand Down Expand Up @@ -631,9 +639,6 @@ static struct sock * unix_create1(struct net *net, struct socket *sock)

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;

Expand Down Expand Up @@ -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;
Expand All @@ -703,7 +709,7 @@ static int unix_autobind(struct socket *sock)
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... */
Expand All @@ -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;
Expand All @@ -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;

Expand All @@ -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;
Expand All @@ -779,6 +786,7 @@ static struct sock *unix_find_other(struct sockaddr_un *sunname, int len,
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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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;

Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -1393,7 +1404,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
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;
Expand Down Expand Up @@ -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;
Expand All @@ -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)
Expand Down Expand Up @@ -2094,15 +2118,35 @@ 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 = {
.owner = THIS_MODULE,
.open = unix_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
.release = unix_seq_release,
};

#endif
Expand All @@ -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;
Expand All @@ -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;
Expand All @@ -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);
Expand Down

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