af_unix.c 67.6 KB
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/*
 * NET4:	Implementation of BSD Unix domain sockets.
 *
4
 * Authors:	Alan Cox, <alan@lxorguk.ukuu.org.uk>
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 *
 *		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.
 *
 * Fixes:
 *		Linus Torvalds	:	Assorted bug cures.
 *		Niibe Yutaka	:	async I/O support.
 *		Carsten Paeth	:	PF_UNIX check, address fixes.
 *		Alan Cox	:	Limit size of allocated blocks.
 *		Alan Cox	:	Fixed the stupid socketpair bug.
 *		Alan Cox	:	BSD compatibility fine tuning.
 *		Alan Cox	:	Fixed a bug in connect when interrupted.
 *		Alan Cox	:	Sorted out a proper draft version of
 *					file descriptor passing hacked up from
 *					Mike Shaver's work.
 *		Marty Leisner	:	Fixes to fd passing
 *		Nick Nevin	:	recvmsg bugfix.
 *		Alan Cox	:	Started proper garbage collector
 *		Heiko EiBfeldt	:	Missing verify_area check
 *		Alan Cox	:	Started POSIXisms
 *		Andreas Schwab	:	Replace inode by dentry for proper
 *					reference counting
 *		Kirk Petersen	:	Made this a module
 *	    Christoph Rohland	:	Elegant non-blocking accept/connect algorithm.
 *					Lots of bug fixes.
 *	     Alexey Kuznetosv	:	Repaired (I hope) bugs introduces
 *					by above two patches.
 *	     Andrea Arcangeli	:	If possible we block in connect(2)
 *					if the max backlog of the listen socket
 *					is been reached. This won't break
 *					old apps and it will avoid huge amount
 *					of socks hashed (this for unix_gc()
 *					performances reasons).
 *					Security fix that limits the max
 *					number of socks to 2*max_files and
 *					the number of skb queueable in the
 *					dgram receiver.
 *		Artur Skawina   :	Hash function optimizations
 *	     Alexey Kuznetsov   :	Full scale SMP. Lot of bugs are introduced 8)
 *	      Malcolm Beattie   :	Set peercred for socketpair
 *	     Michal Ostrowski   :       Module initialization cleanup.
 *	     Arnaldo C. Melo	:	Remove MOD_{INC,DEC}_USE_COUNT,
 *	     				the core infrastructure is doing that
 *	     				for all net proto families now (2.5.69+)
 *
 *
 * Known differences from reference BSD that was tested:
 *
 *	[TO FIX]
 *	ECONNREFUSED is not returned from one end of a connected() socket to the
 *		other the moment one end closes.
 *	fstat() doesn't return st_dev=0, and give the blksize as high water mark
 *		and a fake inode identifier (nor the BSD first socket fstat twice bug).
 *	[NOT TO FIX]
 *	accept() returns a path name even if the connecting socket has closed
 *		in the meantime (BSD loses the path and gives up).
 *	accept() returns 0 length path for an unbound connector. BSD returns 16
 *		and a null first byte in the path (but not for gethost/peername - BSD bug ??)
 *	socketpair(...SOCK_RAW..) doesn't panic the kernel.
 *	BSD af_unix apparently has connect forgetting to block properly.
 *		(need to check this with the POSIX spec in detail)
 *
 * Differences from 2.0.0-11-... (ANK)
 *	Bug fixes and improvements.
 *		- client shutdown killed server socket.
 *		- removed all useless cli/sti pairs.
 *
 *	Semantic changes/extensions.
 *		- generic control message passing.
 *		- SCM_CREDENTIALS control message.
 *		- "Abstract" (not FS based) socket bindings.
 *		  Abstract names are sequences of bytes (not zero terminated)
 *		  started by 0, so that this name space does not intersect
 *		  with BSD names.
 */

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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/dcache.h>
#include <linux/namei.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/in.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
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#include <net/net_namespace.h>
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#include <net/sock.h>
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#include <net/tcp_states.h>
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#include <net/af_unix.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/scm.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/rtnetlink.h>
#include <linux/mount.h>
#include <net/checksum.h>
#include <linux/security.h>
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#include <linux/freezer.h>
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struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
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EXPORT_SYMBOL_GPL(unix_socket_table);
DEFINE_SPINLOCK(unix_table_lock);
EXPORT_SYMBOL_GPL(unix_table_lock);
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static atomic_long_t unix_nr_socks;
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static struct hlist_head *unix_sockets_unbound(void *addr)
{
	unsigned long hash = (unsigned long)addr;

	hash ^= hash >> 16;
	hash ^= hash >> 8;
	hash %= UNIX_HASH_SIZE;
	return &unix_socket_table[UNIX_HASH_SIZE + hash];
}

#define UNIX_ABSTRACT(sk)	(unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
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#ifdef CONFIG_SECURITY_NETWORK
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static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
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{
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	UNIXCB(skb).secid = scm->secid;
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}

static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
{
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	scm->secid = UNIXCB(skb).secid;
}

static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
{
	return (scm->secid == UNIXCB(skb).secid);
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}
#else
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static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
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{ }

static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
{ }
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static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
{
	return true;
}
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#endif /* CONFIG_SECURITY_NETWORK */

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/*
 *  SMP locking strategy:
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 *    hash table is protected with spinlock unix_table_lock
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 *    each socket state is protected by separate spin lock.
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 */

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static inline unsigned int unix_hash_fold(__wsum n)
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{
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	unsigned int hash = (__force unsigned int)csum_fold(n);
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	hash ^= hash>>8;
	return hash&(UNIX_HASH_SIZE-1);
}

#define unix_peer(sk) (unix_sk(sk)->peer)

static inline int unix_our_peer(struct sock *sk, struct sock *osk)
{
	return unix_peer(osk) == sk;
}

static inline int unix_may_send(struct sock *sk, struct sock *osk)
{
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	return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
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}

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static inline int unix_recvq_full(struct sock const *sk)
{
	return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
}

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struct sock *unix_peer_get(struct sock *s)
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{
	struct sock *peer;

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	unix_state_lock(s);
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	peer = unix_peer(s);
	if (peer)
		sock_hold(peer);
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	unix_state_unlock(s);
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	return peer;
}
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EXPORT_SYMBOL_GPL(unix_peer_get);
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static inline void unix_release_addr(struct unix_address *addr)
{
	if (atomic_dec_and_test(&addr->refcnt))
		kfree(addr);
}

/*
 *	Check unix socket name:
 *		- should be not zero length.
 *	        - if started by not zero, should be NULL terminated (FS object)
 *		- if started by zero, it is abstract name.
 */
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static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
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{
	if (len <= sizeof(short) || len > sizeof(*sunaddr))
		return -EINVAL;
	if (!sunaddr || sunaddr->sun_family != AF_UNIX)
		return -EINVAL;
	if (sunaddr->sun_path[0]) {
		/*
		 * This may look like an off by one error but it is a bit more
		 * subtle. 108 is the longest valid AF_UNIX path for a binding.
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		 * sun_path[108] doesn't as such exist.  However in kernel space
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		 * we are guaranteed that it is a valid memory location in our
		 * kernel address buffer.
		 */
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		((char *)sunaddr)[len] = 0;
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		len = strlen(sunaddr->sun_path)+1+sizeof(short);
		return len;
	}

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	*hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
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	return len;
}

static void __unix_remove_socket(struct sock *sk)
{
	sk_del_node_init(sk);
}

static void __unix_insert_socket(struct hlist_head *list, struct sock *sk)
{
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	WARN_ON(!sk_unhashed(sk));
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	sk_add_node(sk, list);
}

static inline void unix_remove_socket(struct sock *sk)
{
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	spin_lock(&unix_table_lock);
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	__unix_remove_socket(sk);
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	spin_unlock(&unix_table_lock);
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}

static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
{
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	spin_lock(&unix_table_lock);
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	__unix_insert_socket(list, sk);
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	spin_unlock(&unix_table_lock);
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}

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static struct sock *__unix_find_socket_byname(struct net *net,
					      struct sockaddr_un *sunname,
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					      int len, int type, unsigned int hash)
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{
	struct sock *s;

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	sk_for_each(s, &unix_socket_table[hash ^ type]) {
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		struct unix_sock *u = unix_sk(s);

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		if (!net_eq(sock_net(s), net))
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			continue;

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		if (u->addr->len == len &&
		    !memcmp(u->addr->name, sunname, len))
			goto found;
	}
	s = NULL;
found:
	return s;
}

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static inline struct sock *unix_find_socket_byname(struct net *net,
						   struct sockaddr_un *sunname,
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						   int len, int type,
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						   unsigned int hash)
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{
	struct sock *s;

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	spin_lock(&unix_table_lock);
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	s = __unix_find_socket_byname(net, sunname, len, type, hash);
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	if (s)
		sock_hold(s);
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	spin_unlock(&unix_table_lock);
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	return s;
}

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static struct sock *unix_find_socket_byinode(struct inode *i)
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{
	struct sock *s;

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	spin_lock(&unix_table_lock);
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	sk_for_each(s,
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		    &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
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		struct dentry *dentry = unix_sk(s)->path.dentry;
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		if (dentry && d_backing_inode(dentry) == i) {
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			sock_hold(s);
			goto found;
		}
	}
	s = NULL;
found:
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	spin_unlock(&unix_table_lock);
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	return s;
}

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/* Support code for asymmetrically connected dgram sockets
 *
 * If a datagram socket is connected to a socket not itself connected
 * to the first socket (eg, /dev/log), clients may only enqueue more
 * messages if the present receive queue of the server socket is not
 * "too large". This means there's a second writeability condition
 * poll and sendmsg need to test. The dgram recv code will do a wake
 * up on the peer_wait wait queue of a socket upon reception of a
 * datagram which needs to be propagated to sleeping would-be writers
 * since these might not have sent anything so far. This can't be
 * accomplished via poll_wait because the lifetime of the server
 * socket might be less than that of its clients if these break their
 * association with it or if the server socket is closed while clients
 * are still connected to it and there's no way to inform "a polling
 * implementation" that it should let go of a certain wait queue
 *
 * In order to propagate a wake up, a wait_queue_t of the client
 * socket is enqueued on the peer_wait queue of the server socket
 * whose wake function does a wake_up on the ordinary client socket
 * wait queue. This connection is established whenever a write (or
 * poll for write) hit the flow control condition and broken when the
 * association to the server socket is dissolved or after a wake up
 * was relayed.
 */

static int unix_dgram_peer_wake_relay(wait_queue_t *q, unsigned mode, int flags,
				      void *key)
{
	struct unix_sock *u;
	wait_queue_head_t *u_sleep;

	u = container_of(q, struct unix_sock, peer_wake);

	__remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
			    q);
	u->peer_wake.private = NULL;

	/* relaying can only happen while the wq still exists */
	u_sleep = sk_sleep(&u->sk);
	if (u_sleep)
		wake_up_interruptible_poll(u_sleep, key);

	return 0;
}

static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other)
{
	struct unix_sock *u, *u_other;
	int rc;

	u = unix_sk(sk);
	u_other = unix_sk(other);
	rc = 0;
	spin_lock(&u_other->peer_wait.lock);

	if (!u->peer_wake.private) {
		u->peer_wake.private = other;
		__add_wait_queue(&u_other->peer_wait, &u->peer_wake);

		rc = 1;
	}

	spin_unlock(&u_other->peer_wait.lock);
	return rc;
}

static void unix_dgram_peer_wake_disconnect(struct sock *sk,
					    struct sock *other)
{
	struct unix_sock *u, *u_other;

	u = unix_sk(sk);
	u_other = unix_sk(other);
	spin_lock(&u_other->peer_wait.lock);

	if (u->peer_wake.private == other) {
		__remove_wait_queue(&u_other->peer_wait, &u->peer_wake);
		u->peer_wake.private = NULL;
	}

	spin_unlock(&u_other->peer_wait.lock);
}

static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk,
						   struct sock *other)
{
	unix_dgram_peer_wake_disconnect(sk, other);
	wake_up_interruptible_poll(sk_sleep(sk),
				   POLLOUT |
				   POLLWRNORM |
				   POLLWRBAND);
}

/* preconditions:
 *	- unix_peer(sk) == other
 *	- association is stable
 */
static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other)
{
	int connected;

	connected = unix_dgram_peer_wake_connect(sk, other);

	if (unix_recvq_full(other))
		return 1;

	if (connected)
		unix_dgram_peer_wake_disconnect(sk, other);

	return 0;
}

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static int unix_writable(const struct sock *sk)
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{
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	return sk->sk_state != TCP_LISTEN &&
	       (atomic_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
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}

static void unix_write_space(struct sock *sk)
{
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	struct socket_wq *wq;

	rcu_read_lock();
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	if (unix_writable(sk)) {
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		wq = rcu_dereference(sk->sk_wq);
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		if (skwq_has_sleeper(wq))
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			wake_up_interruptible_sync_poll(&wq->wait,
				POLLOUT | POLLWRNORM | POLLWRBAND);
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		sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
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	}
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	rcu_read_unlock();
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}

/* When dgram socket disconnects (or changes its peer), we clear its receive
 * queue of packets arrived from previous peer. First, it allows to do
 * flow control based only on wmem_alloc; second, sk connected to peer
 * may receive messages only from that peer. */
static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
{
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	if (!skb_queue_empty(&sk->sk_receive_queue)) {
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		skb_queue_purge(&sk->sk_receive_queue);
		wake_up_interruptible_all(&unix_sk(sk)->peer_wait);

		/* If one link of bidirectional dgram pipe is disconnected,
		 * we signal error. Messages are lost. Do not make this,
		 * when peer was not connected to us.
		 */
		if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
			other->sk_err = ECONNRESET;
			other->sk_error_report(other);
		}
	}
}

static void unix_sock_destructor(struct sock *sk)
{
	struct unix_sock *u = unix_sk(sk);

	skb_queue_purge(&sk->sk_receive_queue);

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	WARN_ON(atomic_read(&sk->sk_wmem_alloc));
	WARN_ON(!sk_unhashed(sk));
	WARN_ON(sk->sk_socket);
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	if (!sock_flag(sk, SOCK_DEAD)) {
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		pr_info("Attempt to release alive unix socket: %p\n", sk);
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		return;
	}

	if (u->addr)
		unix_release_addr(u->addr);

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	atomic_long_dec(&unix_nr_socks);
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	local_bh_disable();
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	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
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	local_bh_enable();
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#ifdef UNIX_REFCNT_DEBUG
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	pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
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		atomic_long_read(&unix_nr_socks));
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#endif
}

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static void unix_release_sock(struct sock *sk, int embrion)
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{
	struct unix_sock *u = unix_sk(sk);
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	struct path path;
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	struct sock *skpair;
	struct sk_buff *skb;
	int state;

	unix_remove_socket(sk);

	/* Clear state */
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	unix_state_lock(sk);
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	sock_orphan(sk);
	sk->sk_shutdown = SHUTDOWN_MASK;
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	path	     = u->path;
	u->path.dentry = NULL;
	u->path.mnt = NULL;
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	state = sk->sk_state;
	sk->sk_state = TCP_CLOSE;
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	unix_state_unlock(sk);
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	wake_up_interruptible_all(&u->peer_wait);

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	skpair = unix_peer(sk);
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	if (skpair != NULL) {
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		if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
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			unix_state_lock(skpair);
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			/* No more writes */
			skpair->sk_shutdown = SHUTDOWN_MASK;
			if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
				skpair->sk_err = ECONNRESET;
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			unix_state_unlock(skpair);
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			skpair->sk_state_change(skpair);
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			sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
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		}
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		unix_dgram_peer_wake_disconnect(sk, skpair);
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		sock_put(skpair); /* It may now die */
		unix_peer(sk) = NULL;
	}

	/* Try to flush out this socket. Throw out buffers at least */

	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
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		if (state == TCP_LISTEN)
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			unix_release_sock(skb->sk, 1);
		/* passed fds are erased in the kfree_skb hook	      */
558
		UNIXCB(skb).consumed = skb->len;
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		kfree_skb(skb);
	}

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Al Viro 已提交
562 563
	if (path.dentry)
		path_put(&path);
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564 565 566 567 568 569

	sock_put(sk);

	/* ---- Socket is dead now and most probably destroyed ---- */

	/*
A
Alan Cox 已提交
570
	 * Fixme: BSD difference: In BSD all sockets connected to us get
L
Linus Torvalds 已提交
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	 *	  ECONNRESET and we die on the spot. In Linux we behave
	 *	  like files and pipes do and wait for the last
	 *	  dereference.
	 *
	 * Can't we simply set sock->err?
	 *
	 *	  What the above comment does talk about? --ANK(980817)
	 */

580
	if (unix_tot_inflight)
581
		unix_gc();		/* Garbage collect fds */
L
Linus Torvalds 已提交
582 583
}

584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601
static void init_peercred(struct sock *sk)
{
	put_pid(sk->sk_peer_pid);
	if (sk->sk_peer_cred)
		put_cred(sk->sk_peer_cred);
	sk->sk_peer_pid  = get_pid(task_tgid(current));
	sk->sk_peer_cred = get_current_cred();
}

static void copy_peercred(struct sock *sk, struct sock *peersk)
{
	put_pid(sk->sk_peer_pid);
	if (sk->sk_peer_cred)
		put_cred(sk->sk_peer_cred);
	sk->sk_peer_pid  = get_pid(peersk->sk_peer_pid);
	sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
}

L
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602 603 604 605 606
static int unix_listen(struct socket *sock, int backlog)
{
	int err;
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
607
	struct pid *old_pid = NULL;
L
Linus Torvalds 已提交
608 609

	err = -EOPNOTSUPP;
E
Eric Dumazet 已提交
610 611
	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
		goto out;	/* Only stream/seqpacket sockets accept */
L
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612 613
	err = -EINVAL;
	if (!u->addr)
E
Eric Dumazet 已提交
614
		goto out;	/* No listens on an unbound socket */
615
	unix_state_lock(sk);
L
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	if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
		goto out_unlock;
	if (backlog > sk->sk_max_ack_backlog)
		wake_up_interruptible_all(&u->peer_wait);
	sk->sk_max_ack_backlog	= backlog;
	sk->sk_state		= TCP_LISTEN;
	/* set credentials so connect can copy them */
623
	init_peercred(sk);
L
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624 625 626
	err = 0;

out_unlock:
627
	unix_state_unlock(sk);
628
	put_pid(old_pid);
L
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629 630 631 632 633 634 635 636 637 638 639 640
out:
	return err;
}

static int unix_release(struct socket *);
static int unix_bind(struct socket *, struct sockaddr *, int);
static int unix_stream_connect(struct socket *, struct sockaddr *,
			       int addr_len, int flags);
static int unix_socketpair(struct socket *, struct socket *);
static int unix_accept(struct socket *, struct socket *, int);
static int unix_getname(struct socket *, struct sockaddr *, int *, int);
static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
641 642
static unsigned int unix_dgram_poll(struct file *, struct socket *,
				    poll_table *);
L
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static int unix_ioctl(struct socket *, unsigned int, unsigned long);
static int unix_shutdown(struct socket *, int);
645 646
static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
647 648
static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
				    size_t size, int flags);
649 650 651
static ssize_t unix_stream_splice_read(struct socket *,  loff_t *ppos,
				       struct pipe_inode_info *, size_t size,
				       unsigned int flags);
652 653
static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
L
Linus Torvalds 已提交
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static int unix_dgram_connect(struct socket *, struct sockaddr *,
			      int, int);
656 657 658
static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
				  int);
L
Linus Torvalds 已提交
659

660
static int unix_set_peek_off(struct sock *sk, int val)
661 662 663
{
	struct unix_sock *u = unix_sk(sk);

664
	if (mutex_lock_interruptible(&u->iolock))
665 666
		return -EINTR;

667
	sk->sk_peek_off = val;
668
	mutex_unlock(&u->iolock);
669 670

	return 0;
671 672 673
}


674
static const struct proto_ops unix_stream_ops = {
L
Linus Torvalds 已提交
675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691
	.family =	PF_UNIX,
	.owner =	THIS_MODULE,
	.release =	unix_release,
	.bind =		unix_bind,
	.connect =	unix_stream_connect,
	.socketpair =	unix_socketpair,
	.accept =	unix_accept,
	.getname =	unix_getname,
	.poll =		unix_poll,
	.ioctl =	unix_ioctl,
	.listen =	unix_listen,
	.shutdown =	unix_shutdown,
	.setsockopt =	sock_no_setsockopt,
	.getsockopt =	sock_no_getsockopt,
	.sendmsg =	unix_stream_sendmsg,
	.recvmsg =	unix_stream_recvmsg,
	.mmap =		sock_no_mmap,
692
	.sendpage =	unix_stream_sendpage,
693
	.splice_read =	unix_stream_splice_read,
694
	.set_peek_off =	unix_set_peek_off,
L
Linus Torvalds 已提交
695 696
};

697
static const struct proto_ops unix_dgram_ops = {
L
Linus Torvalds 已提交
698 699 700 701 702 703 704 705
	.family =	PF_UNIX,
	.owner =	THIS_MODULE,
	.release =	unix_release,
	.bind =		unix_bind,
	.connect =	unix_dgram_connect,
	.socketpair =	unix_socketpair,
	.accept =	sock_no_accept,
	.getname =	unix_getname,
706
	.poll =		unix_dgram_poll,
L
Linus Torvalds 已提交
707 708 709 710 711 712 713 714 715
	.ioctl =	unix_ioctl,
	.listen =	sock_no_listen,
	.shutdown =	unix_shutdown,
	.setsockopt =	sock_no_setsockopt,
	.getsockopt =	sock_no_getsockopt,
	.sendmsg =	unix_dgram_sendmsg,
	.recvmsg =	unix_dgram_recvmsg,
	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
716
	.set_peek_off =	unix_set_peek_off,
L
Linus Torvalds 已提交
717 718
};

719
static const struct proto_ops unix_seqpacket_ops = {
L
Linus Torvalds 已提交
720 721 722 723 724 725 726 727
	.family =	PF_UNIX,
	.owner =	THIS_MODULE,
	.release =	unix_release,
	.bind =		unix_bind,
	.connect =	unix_stream_connect,
	.socketpair =	unix_socketpair,
	.accept =	unix_accept,
	.getname =	unix_getname,
728
	.poll =		unix_dgram_poll,
L
Linus Torvalds 已提交
729 730 731 732 733 734
	.ioctl =	unix_ioctl,
	.listen =	unix_listen,
	.shutdown =	unix_shutdown,
	.setsockopt =	sock_no_setsockopt,
	.getsockopt =	sock_no_getsockopt,
	.sendmsg =	unix_seqpacket_sendmsg,
735
	.recvmsg =	unix_seqpacket_recvmsg,
L
Linus Torvalds 已提交
736 737
	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
738
	.set_peek_off =	unix_set_peek_off,
L
Linus Torvalds 已提交
739 740 741
};

static struct proto unix_proto = {
742 743 744
	.name			= "UNIX",
	.owner			= THIS_MODULE,
	.obj_size		= sizeof(struct unix_sock),
L
Linus Torvalds 已提交
745 746
};

747 748 749 750 751 752 753 754
/*
 * AF_UNIX sockets do not interact with hardware, hence they
 * dont trigger interrupts - so it's safe for them to have
 * bh-unsafe locking for their sk_receive_queue.lock. Split off
 * this special lock-class by reinitializing the spinlock key:
 */
static struct lock_class_key af_unix_sk_receive_queue_lock_key;

755
static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
L
Linus Torvalds 已提交
756 757 758 759
{
	struct sock *sk = NULL;
	struct unix_sock *u;

E
Eric Dumazet 已提交
760 761
	atomic_long_inc(&unix_nr_socks);
	if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
L
Linus Torvalds 已提交
762 763
		goto out;

764
	sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
L
Linus Torvalds 已提交
765 766 767
	if (!sk)
		goto out;

E
Eric Dumazet 已提交
768
	sock_init_data(sock, sk);
769 770
	lockdep_set_class(&sk->sk_receive_queue.lock,
				&af_unix_sk_receive_queue_lock_key);
L
Linus Torvalds 已提交
771

772
	sk->sk_allocation	= GFP_KERNEL_ACCOUNT;
L
Linus Torvalds 已提交
773
	sk->sk_write_space	= unix_write_space;
774
	sk->sk_max_ack_backlog	= net->unx.sysctl_max_dgram_qlen;
L
Linus Torvalds 已提交
775 776
	sk->sk_destruct		= unix_sock_destructor;
	u	  = unix_sk(sk);
A
Al Viro 已提交
777 778
	u->path.dentry = NULL;
	u->path.mnt = NULL;
779
	spin_lock_init(&u->lock);
A
Al Viro 已提交
780
	atomic_long_set(&u->inflight, 0);
781
	INIT_LIST_HEAD(&u->link);
782 783
	mutex_init(&u->iolock); /* single task reading lock */
	mutex_init(&u->bindlock); /* single task binding lock */
L
Linus Torvalds 已提交
784
	init_waitqueue_head(&u->peer_wait);
785
	init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
E
Eric Dumazet 已提交
786
	unix_insert_socket(unix_sockets_unbound(sk), sk);
L
Linus Torvalds 已提交
787
out:
788
	if (sk == NULL)
E
Eric Dumazet 已提交
789
		atomic_long_dec(&unix_nr_socks);
790 791
	else {
		local_bh_disable();
792
		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
793 794
		local_bh_enable();
	}
L
Linus Torvalds 已提交
795 796 797
	return sk;
}

798 799
static int unix_create(struct net *net, struct socket *sock, int protocol,
		       int kern)
L
Linus Torvalds 已提交
800 801 802 803 804 805 806 807 808 809 810 811 812 813 814
{
	if (protocol && protocol != PF_UNIX)
		return -EPROTONOSUPPORT;

	sock->state = SS_UNCONNECTED;

	switch (sock->type) {
	case SOCK_STREAM:
		sock->ops = &unix_stream_ops;
		break;
		/*
		 *	Believe it or not BSD has AF_UNIX, SOCK_RAW though
		 *	nothing uses it.
		 */
	case SOCK_RAW:
815
		sock->type = SOCK_DGRAM;
L
Linus Torvalds 已提交
816 817 818 819 820 821 822 823 824 825
	case SOCK_DGRAM:
		sock->ops = &unix_dgram_ops;
		break;
	case SOCK_SEQPACKET:
		sock->ops = &unix_seqpacket_ops;
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}

826
	return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
L
Linus Torvalds 已提交
827 828 829 830 831 832 833 834 835
}

static int unix_release(struct socket *sock)
{
	struct sock *sk = sock->sk;

	if (!sk)
		return 0;

836
	unix_release_sock(sk, 0);
L
Linus Torvalds 已提交
837 838
	sock->sk = NULL;

839
	return 0;
L
Linus Torvalds 已提交
840 841 842 843 844
}

static int unix_autobind(struct socket *sock)
{
	struct sock *sk = sock->sk;
845
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
846 847
	struct unix_sock *u = unix_sk(sk);
	static u32 ordernum = 1;
E
Eric Dumazet 已提交
848
	struct unix_address *addr;
L
Linus Torvalds 已提交
849
	int err;
850
	unsigned int retries = 0;
L
Linus Torvalds 已提交
851

852
	err = mutex_lock_interruptible(&u->bindlock);
853 854
	if (err)
		return err;
L
Linus Torvalds 已提交
855 856 857 858 859 860

	err = 0;
	if (u->addr)
		goto out;

	err = -ENOMEM;
861
	addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
L
Linus Torvalds 已提交
862 863 864 865 866 867 868 869
	if (!addr)
		goto out;

	addr->name->sun_family = AF_UNIX;
	atomic_set(&addr->refcnt, 1);

retry:
	addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
870
	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
L
Linus Torvalds 已提交
871

872
	spin_lock(&unix_table_lock);
L
Linus Torvalds 已提交
873 874
	ordernum = (ordernum+1)&0xFFFFF;

875
	if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
L
Linus Torvalds 已提交
876
				      addr->hash)) {
877
		spin_unlock(&unix_table_lock);
878 879 880 881 882 883 884 885 886 887 888
		/*
		 * __unix_find_socket_byname() may take long time if many names
		 * are already in use.
		 */
		cond_resched();
		/* Give up if all names seems to be in use. */
		if (retries++ == 0xFFFFF) {
			err = -ENOSPC;
			kfree(addr);
			goto out;
		}
L
Linus Torvalds 已提交
889 890 891 892 893 894 895
		goto retry;
	}
	addr->hash ^= sk->sk_type;

	__unix_remove_socket(sk);
	u->addr = addr;
	__unix_insert_socket(&unix_socket_table[addr->hash], sk);
896
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
897 898
	err = 0;

899
out:	mutex_unlock(&u->bindlock);
L
Linus Torvalds 已提交
900 901 902
	return err;
}

903 904
static struct sock *unix_find_other(struct net *net,
				    struct sockaddr_un *sunname, int len,
905
				    int type, unsigned int hash, int *error)
L
Linus Torvalds 已提交
906 907
{
	struct sock *u;
908
	struct path path;
L
Linus Torvalds 已提交
909
	int err = 0;
910

L
Linus Torvalds 已提交
911
	if (sunname->sun_path[0]) {
912 913
		struct inode *inode;
		err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
L
Linus Torvalds 已提交
914 915
		if (err)
			goto fail;
916
		inode = d_backing_inode(path.dentry);
917
		err = inode_permission(inode, MAY_WRITE);
L
Linus Torvalds 已提交
918 919 920 921
		if (err)
			goto put_fail;

		err = -ECONNREFUSED;
922
		if (!S_ISSOCK(inode->i_mode))
L
Linus Torvalds 已提交
923
			goto put_fail;
924
		u = unix_find_socket_byinode(inode);
L
Linus Torvalds 已提交
925 926 927 928
		if (!u)
			goto put_fail;

		if (u->sk_type == type)
A
Al Viro 已提交
929
			touch_atime(&path);
L
Linus Torvalds 已提交
930

931
		path_put(&path);
L
Linus Torvalds 已提交
932

933
		err = -EPROTOTYPE;
L
Linus Torvalds 已提交
934 935 936 937 938 939
		if (u->sk_type != type) {
			sock_put(u);
			goto fail;
		}
	} else {
		err = -ECONNREFUSED;
940
		u = unix_find_socket_byname(net, sunname, len, type, hash);
L
Linus Torvalds 已提交
941 942
		if (u) {
			struct dentry *dentry;
A
Al Viro 已提交
943
			dentry = unix_sk(u)->path.dentry;
L
Linus Torvalds 已提交
944
			if (dentry)
A
Al Viro 已提交
945
				touch_atime(&unix_sk(u)->path);
L
Linus Torvalds 已提交
946 947 948 949 950 951
		} else
			goto fail;
	}
	return u;

put_fail:
952
	path_put(&path);
L
Linus Torvalds 已提交
953
fail:
954
	*error = err;
L
Linus Torvalds 已提交
955 956 957
	return NULL;
}

958
static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
A
Al Viro 已提交
959
{
960 961 962 963 964 965 966 967 968 969 970
	struct dentry *dentry;
	struct path path;
	int err = 0;
	/*
	 * Get the parent directory, calculate the hash for last
	 * component.
	 */
	dentry = kern_path_create(AT_FDCWD, sun_path, &path, 0);
	err = PTR_ERR(dentry);
	if (IS_ERR(dentry))
		return err;
A
Al Viro 已提交
971

972 973 974 975
	/*
	 * All right, let's create it.
	 */
	err = security_path_mknod(&path, dentry, mode, 0);
A
Al Viro 已提交
976
	if (!err) {
977
		err = vfs_mknod(d_inode(path.dentry), dentry, mode, 0);
A
Al Viro 已提交
978
		if (!err) {
979
			res->mnt = mntget(path.mnt);
A
Al Viro 已提交
980 981 982
			res->dentry = dget(dentry);
		}
	}
983
	done_path_create(&path, dentry);
A
Al Viro 已提交
984 985
	return err;
}
L
Linus Torvalds 已提交
986 987 988 989

static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
	struct sock *sk = sock->sk;
990
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
991
	struct unix_sock *u = unix_sk(sk);
992
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
993
	char *sun_path = sunaddr->sun_path;
994
	int err;
995
	unsigned int hash;
L
Linus Torvalds 已提交
996 997 998 999 1000 1001 1002
	struct unix_address *addr;
	struct hlist_head *list;

	err = -EINVAL;
	if (sunaddr->sun_family != AF_UNIX)
		goto out;

1003
	if (addr_len == sizeof(short)) {
L
Linus Torvalds 已提交
1004 1005 1006 1007 1008 1009 1010 1011 1012
		err = unix_autobind(sock);
		goto out;
	}

	err = unix_mkname(sunaddr, addr_len, &hash);
	if (err < 0)
		goto out;
	addr_len = err;

1013
	err = mutex_lock_interruptible(&u->bindlock);
1014
	if (err)
1015
		goto out;
L
Linus Torvalds 已提交
1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030

	err = -EINVAL;
	if (u->addr)
		goto out_up;

	err = -ENOMEM;
	addr = kmalloc(sizeof(*addr)+addr_len, GFP_KERNEL);
	if (!addr)
		goto out_up;

	memcpy(addr->name, sunaddr, addr_len);
	addr->len = addr_len;
	addr->hash = hash ^ sk->sk_type;
	atomic_set(&addr->refcnt, 1);

1031 1032
	if (sun_path[0]) {
		struct path path;
A
Al Viro 已提交
1033
		umode_t mode = S_IFSOCK |
A
Al Viro 已提交
1034
		       (SOCK_INODE(sock)->i_mode & ~current_umask());
1035
		err = unix_mknod(sun_path, mode, &path);
A
Al Viro 已提交
1036 1037 1038 1039 1040 1041
		if (err) {
			if (err == -EEXIST)
				err = -EADDRINUSE;
			unix_release_addr(addr);
			goto out_up;
		}
L
Linus Torvalds 已提交
1042
		addr->hash = UNIX_HASH_SIZE;
1043
		hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE - 1);
A
Al Viro 已提交
1044
		spin_lock(&unix_table_lock);
1045
		u->path = path;
A
Al Viro 已提交
1046 1047 1048
		list = &unix_socket_table[hash];
	} else {
		spin_lock(&unix_table_lock);
L
Linus Torvalds 已提交
1049
		err = -EADDRINUSE;
1050
		if (__unix_find_socket_byname(net, sunaddr, addr_len,
L
Linus Torvalds 已提交
1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064
					      sk->sk_type, hash)) {
			unix_release_addr(addr);
			goto out_unlock;
		}

		list = &unix_socket_table[addr->hash];
	}

	err = 0;
	__unix_remove_socket(sk);
	u->addr = addr;
	__unix_insert_socket(list, sk);

out_unlock:
1065
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
1066
out_up:
1067
	mutex_unlock(&u->bindlock);
L
Linus Torvalds 已提交
1068 1069 1070 1071
out:
	return err;
}

1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096
static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
{
	if (unlikely(sk1 == sk2) || !sk2) {
		unix_state_lock(sk1);
		return;
	}
	if (sk1 < sk2) {
		unix_state_lock(sk1);
		unix_state_lock_nested(sk2);
	} else {
		unix_state_lock(sk2);
		unix_state_lock_nested(sk1);
	}
}

static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
{
	if (unlikely(sk1 == sk2) || !sk2) {
		unix_state_unlock(sk1);
		return;
	}
	unix_state_unlock(sk1);
	unix_state_unlock(sk2);
}

L
Linus Torvalds 已提交
1097 1098 1099 1100
static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
			      int alen, int flags)
{
	struct sock *sk = sock->sk;
1101
	struct net *net = sock_net(sk);
1102
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
L
Linus Torvalds 已提交
1103
	struct sock *other;
1104
	unsigned int hash;
L
Linus Torvalds 已提交
1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116
	int err;

	if (addr->sa_family != AF_UNSPEC) {
		err = unix_mkname(sunaddr, alen, &hash);
		if (err < 0)
			goto out;
		alen = err;

		if (test_bit(SOCK_PASSCRED, &sock->flags) &&
		    !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
			goto out;

1117
restart:
1118
		other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
L
Linus Torvalds 已提交
1119 1120 1121
		if (!other)
			goto out;

1122 1123 1124 1125 1126 1127 1128 1129
		unix_state_double_lock(sk, other);

		/* Apparently VFS overslept socket death. Retry. */
		if (sock_flag(other, SOCK_DEAD)) {
			unix_state_double_unlock(sk, other);
			sock_put(other);
			goto restart;
		}
L
Linus Torvalds 已提交
1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143

		err = -EPERM;
		if (!unix_may_send(sk, other))
			goto out_unlock;

		err = security_unix_may_send(sk->sk_socket, other->sk_socket);
		if (err)
			goto out_unlock;

	} else {
		/*
		 *	1003.1g breaking connected state with AF_UNSPEC
		 */
		other = NULL;
1144
		unix_state_double_lock(sk, other);
L
Linus Torvalds 已提交
1145 1146 1147 1148 1149 1150 1151
	}

	/*
	 * If it was connected, reconnect.
	 */
	if (unix_peer(sk)) {
		struct sock *old_peer = unix_peer(sk);
1152
		unix_peer(sk) = other;
1153 1154
		unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);

1155
		unix_state_double_unlock(sk, other);
L
Linus Torvalds 已提交
1156 1157 1158 1159 1160

		if (other != old_peer)
			unix_dgram_disconnected(sk, old_peer);
		sock_put(old_peer);
	} else {
1161
		unix_peer(sk) = other;
1162
		unix_state_double_unlock(sk, other);
L
Linus Torvalds 已提交
1163
	}
1164
	return 0;
L
Linus Torvalds 已提交
1165 1166

out_unlock:
1167
	unix_state_double_unlock(sk, other);
L
Linus Torvalds 已提交
1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182
	sock_put(other);
out:
	return err;
}

static long unix_wait_for_peer(struct sock *other, long timeo)
{
	struct unix_sock *u = unix_sk(other);
	int sched;
	DEFINE_WAIT(wait);

	prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE);

	sched = !sock_flag(other, SOCK_DEAD) &&
		!(other->sk_shutdown & RCV_SHUTDOWN) &&
1183
		unix_recvq_full(other);
L
Linus Torvalds 已提交
1184

1185
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196

	if (sched)
		timeo = schedule_timeout(timeo);

	finish_wait(&u->peer_wait, &wait);
	return timeo;
}

static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
			       int addr_len, int flags)
{
1197
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
L
Linus Torvalds 已提交
1198
	struct sock *sk = sock->sk;
1199
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1200 1201 1202 1203
	struct unix_sock *u = unix_sk(sk), *newu, *otheru;
	struct sock *newsk = NULL;
	struct sock *other = NULL;
	struct sk_buff *skb = NULL;
1204
	unsigned int hash;
L
Linus Torvalds 已提交
1205 1206 1207 1208 1209 1210 1211 1212 1213
	int st;
	int err;
	long timeo;

	err = unix_mkname(sunaddr, addr_len, &hash);
	if (err < 0)
		goto out;
	addr_len = err;

1214 1215
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
	    (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227
		goto out;

	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);

	/* First of all allocate resources.
	   If we will make it after state is locked,
	   we will have to recheck all again in any case.
	 */

	err = -ENOMEM;

	/* create new sock for complete connection */
1228
	newsk = unix_create1(sock_net(sk), NULL, 0);
L
Linus Torvalds 已提交
1229 1230 1231 1232 1233 1234 1235 1236 1237 1238
	if (newsk == NULL)
		goto out;

	/* Allocate skb for sending to listening sock */
	skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);
	if (skb == NULL)
		goto out;

restart:
	/*  Find listening sock. */
1239
	other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
L
Linus Torvalds 已提交
1240 1241 1242 1243
	if (!other)
		goto out;

	/* Latch state of peer */
1244
	unix_state_lock(other);
L
Linus Torvalds 已提交
1245 1246 1247

	/* Apparently VFS overslept socket death. Retry. */
	if (sock_flag(other, SOCK_DEAD)) {
1248
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1249 1250 1251 1252 1253 1254 1255
		sock_put(other);
		goto restart;
	}

	err = -ECONNREFUSED;
	if (other->sk_state != TCP_LISTEN)
		goto out_unlock;
1256 1257
	if (other->sk_shutdown & RCV_SHUTDOWN)
		goto out_unlock;
L
Linus Torvalds 已提交
1258

1259
	if (unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270
		err = -EAGAIN;
		if (!timeo)
			goto out_unlock;

		timeo = unix_wait_for_peer(other, timeo);

		err = sock_intr_errno(timeo);
		if (signal_pending(current))
			goto out;
		sock_put(other);
		goto restart;
1271
	}
L
Linus Torvalds 已提交
1272 1273 1274

	/* Latch our state.

D
Daniel Baluta 已提交
1275
	   It is tricky place. We need to grab our state lock and cannot
L
Linus Torvalds 已提交
1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298
	   drop lock on peer. It is dangerous because deadlock is
	   possible. Connect to self case and simultaneous
	   attempt to connect are eliminated by checking socket
	   state. other is TCP_LISTEN, if sk is TCP_LISTEN we
	   check this before attempt to grab lock.

	   Well, and we have to recheck the state after socket locked.
	 */
	st = sk->sk_state;

	switch (st) {
	case TCP_CLOSE:
		/* This is ok... continue with connect */
		break;
	case TCP_ESTABLISHED:
		/* Socket is already connected */
		err = -EISCONN;
		goto out_unlock;
	default:
		err = -EINVAL;
		goto out_unlock;
	}

1299
	unix_state_lock_nested(sk);
L
Linus Torvalds 已提交
1300 1301

	if (sk->sk_state != st) {
1302 1303
		unix_state_unlock(sk);
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1304 1305 1306 1307
		sock_put(other);
		goto restart;
	}

1308
	err = security_unix_stream_connect(sk, other, newsk);
L
Linus Torvalds 已提交
1309
	if (err) {
1310
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1311 1312 1313 1314 1315 1316 1317 1318 1319
		goto out_unlock;
	}

	/* The way is open! Fastly set all the necessary fields... */

	sock_hold(sk);
	unix_peer(newsk)	= sk;
	newsk->sk_state		= TCP_ESTABLISHED;
	newsk->sk_type		= sk->sk_type;
1320
	init_peercred(newsk);
L
Linus Torvalds 已提交
1321
	newu = unix_sk(newsk);
1322
	RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
L
Linus Torvalds 已提交
1323 1324 1325 1326 1327 1328 1329
	otheru = unix_sk(other);

	/* copy address information from listening to new sock*/
	if (otheru->addr) {
		atomic_inc(&otheru->addr->refcnt);
		newu->addr = otheru->addr;
	}
A
Al Viro 已提交
1330 1331 1332
	if (otheru->path.dentry) {
		path_get(&otheru->path);
		newu->path = otheru->path;
L
Linus Torvalds 已提交
1333 1334 1335
	}

	/* Set credentials */
1336
	copy_peercred(sk, other);
L
Linus Torvalds 已提交
1337 1338 1339

	sock->state	= SS_CONNECTED;
	sk->sk_state	= TCP_ESTABLISHED;
1340 1341
	sock_hold(newsk);

1342
	smp_mb__after_atomic();	/* sock_hold() does an atomic_inc() */
1343
	unix_peer(sk)	= newsk;
L
Linus Torvalds 已提交
1344

1345
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1346 1347 1348 1349 1350

	/* take ten and and send info to listening sock */
	spin_lock(&other->sk_receive_queue.lock);
	__skb_queue_tail(&other->sk_receive_queue, skb);
	spin_unlock(&other->sk_receive_queue.lock);
1351
	unix_state_unlock(other);
1352
	other->sk_data_ready(other);
L
Linus Torvalds 已提交
1353 1354 1355 1356 1357
	sock_put(other);
	return 0;

out_unlock:
	if (other)
1358
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1359 1360

out:
1361
	kfree_skb(skb);
L
Linus Torvalds 已提交
1362 1363 1364 1365 1366 1367 1368 1369 1370
	if (newsk)
		unix_release_sock(newsk, 0);
	if (other)
		sock_put(other);
	return err;
}

static int unix_socketpair(struct socket *socka, struct socket *sockb)
{
1371
	struct sock *ska = socka->sk, *skb = sockb->sk;
L
Linus Torvalds 已提交
1372 1373 1374 1375

	/* Join our sockets back to back */
	sock_hold(ska);
	sock_hold(skb);
1376 1377
	unix_peer(ska) = skb;
	unix_peer(skb) = ska;
1378 1379
	init_peercred(ska);
	init_peercred(skb);
L
Linus Torvalds 已提交
1380 1381 1382 1383 1384 1385 1386 1387 1388 1389

	if (ska->sk_type != SOCK_DGRAM) {
		ska->sk_state = TCP_ESTABLISHED;
		skb->sk_state = TCP_ESTABLISHED;
		socka->state  = SS_CONNECTED;
		sockb->state  = SS_CONNECTED;
	}
	return 0;
}

1390 1391 1392 1393 1394 1395 1396 1397 1398
static void unix_sock_inherit_flags(const struct socket *old,
				    struct socket *new)
{
	if (test_bit(SOCK_PASSCRED, &old->flags))
		set_bit(SOCK_PASSCRED, &new->flags);
	if (test_bit(SOCK_PASSSEC, &old->flags))
		set_bit(SOCK_PASSSEC, &new->flags);
}

L
Linus Torvalds 已提交
1399 1400 1401 1402 1403 1404 1405 1406
static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
{
	struct sock *sk = sock->sk;
	struct sock *tsk;
	struct sk_buff *skb;
	int err;

	err = -EOPNOTSUPP;
E
Eric Dumazet 已提交
1407
	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
L
Linus Torvalds 已提交
1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430
		goto out;

	err = -EINVAL;
	if (sk->sk_state != TCP_LISTEN)
		goto out;

	/* If socket state is TCP_LISTEN it cannot change (for now...),
	 * so that no locks are necessary.
	 */

	skb = skb_recv_datagram(sk, 0, flags&O_NONBLOCK, &err);
	if (!skb) {
		/* This means receive shutdown. */
		if (err == 0)
			err = -EINVAL;
		goto out;
	}

	tsk = skb->sk;
	skb_free_datagram(sk, skb);
	wake_up_interruptible(&unix_sk(sk)->peer_wait);

	/* attach accepted sock to socket */
1431
	unix_state_lock(tsk);
L
Linus Torvalds 已提交
1432
	newsock->state = SS_CONNECTED;
1433
	unix_sock_inherit_flags(sock, newsock);
L
Linus Torvalds 已提交
1434
	sock_graft(tsk, newsock);
1435
	unix_state_unlock(tsk);
L
Linus Torvalds 已提交
1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446
	return 0;

out:
	return err;
}


static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_len, int peer)
{
	struct sock *sk = sock->sk;
	struct unix_sock *u;
1447
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
L
Linus Torvalds 已提交
1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461
	int err = 0;

	if (peer) {
		sk = unix_peer_get(sk);

		err = -ENOTCONN;
		if (!sk)
			goto out;
		err = 0;
	} else {
		sock_hold(sk);
	}

	u = unix_sk(sk);
1462
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1463 1464 1465 1466 1467 1468 1469 1470 1471 1472
	if (!u->addr) {
		sunaddr->sun_family = AF_UNIX;
		sunaddr->sun_path[0] = 0;
		*uaddr_len = sizeof(short);
	} else {
		struct unix_address *addr = u->addr;

		*uaddr_len = addr->len;
		memcpy(sunaddr, addr->name, *uaddr_len);
	}
1473
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485
	sock_put(sk);
out:
	return err;
}

static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
{
	int i;

	scm->fp = UNIXCB(skb).fp;
	UNIXCB(skb).fp = NULL;

E
Eric Dumazet 已提交
1486
	for (i = scm->fp->count-1; i >= 0; i--)
1487
		unix_notinflight(scm->fp->user, scm->fp->fp[i]);
L
Linus Torvalds 已提交
1488 1489
}

1490
static void unix_destruct_scm(struct sk_buff *skb)
L
Linus Torvalds 已提交
1491 1492 1493
{
	struct scm_cookie scm;
	memset(&scm, 0, sizeof(scm));
1494 1495 1496
	scm.pid  = UNIXCB(skb).pid;
	if (UNIXCB(skb).fp)
		unix_detach_fds(&scm, skb);
L
Linus Torvalds 已提交
1497 1498 1499 1500 1501 1502 1503

	/* Alas, it calls VFS */
	/* So fscking what? fput() had been SMP-safe since the last Summer */
	scm_destroy(&scm);
	sock_wfree(skb);
}

1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518
/*
 * The "user->unix_inflight" variable is protected by the garbage
 * collection lock, and we just read it locklessly here. If you go
 * over the limit, there might be a tiny race in actually noticing
 * it across threads. Tough.
 */
static inline bool too_many_unix_fds(struct task_struct *p)
{
	struct user_struct *user = current_user();

	if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))
		return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
	return false;
}

E
Eric Dumazet 已提交
1519 1520
#define MAX_RECURSION_LEVEL 4

1521
static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
L
Linus Torvalds 已提交
1522 1523
{
	int i;
E
Eric Dumazet 已提交
1524 1525
	unsigned char max_level = 0;

1526 1527 1528
	if (too_many_unix_fds(current))
		return -ETOOMANYREFS;

E
Eric Dumazet 已提交
1529 1530 1531
	for (i = scm->fp->count - 1; i >= 0; i--) {
		struct sock *sk = unix_get_socket(scm->fp->fp[i]);

1532
		if (sk)
E
Eric Dumazet 已提交
1533 1534 1535 1536 1537
			max_level = max(max_level,
					unix_sk(sk)->recursion_level);
	}
	if (unlikely(max_level > MAX_RECURSION_LEVEL))
		return -ETOOMANYREFS;
1538 1539 1540 1541 1542 1543 1544 1545 1546 1547

	/*
	 * Need to duplicate file references for the sake of garbage
	 * collection.  Otherwise a socket in the fps might become a
	 * candidate for GC while the skb is not yet queued.
	 */
	UNIXCB(skb).fp = scm_fp_dup(scm->fp);
	if (!UNIXCB(skb).fp)
		return -ENOMEM;

1548
	for (i = scm->fp->count - 1; i >= 0; i--)
1549
		unix_inflight(scm->fp->user, scm->fp->fp[i]);
E
Eric Dumazet 已提交
1550
	return max_level;
L
Linus Torvalds 已提交
1551 1552
}

1553
static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1554 1555
{
	int err = 0;
1556

1557
	UNIXCB(skb).pid  = get_pid(scm->pid);
1558 1559
	UNIXCB(skb).uid = scm->creds.uid;
	UNIXCB(skb).gid = scm->creds.gid;
1560
	UNIXCB(skb).fp = NULL;
1561
	unix_get_secdata(scm, skb);
1562 1563 1564 1565 1566 1567 1568
	if (scm->fp && send_fds)
		err = unix_attach_fds(scm, skb);

	skb->destructor = unix_destruct_scm;
	return err;
}

1569 1570 1571 1572 1573 1574 1575 1576
static bool unix_passcred_enabled(const struct socket *sock,
				  const struct sock *other)
{
	return test_bit(SOCK_PASSCRED, &sock->flags) ||
	       !other->sk_socket ||
	       test_bit(SOCK_PASSCRED, &other->sk_socket->flags);
}

1577 1578 1579 1580 1581 1582 1583 1584
/*
 * Some apps rely on write() giving SCM_CREDENTIALS
 * We include credentials if source or destination socket
 * asserted SOCK_PASSCRED.
 */
static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
			    const struct sock *other)
{
1585
	if (UNIXCB(skb).pid)
1586
		return;
1587
	if (unix_passcred_enabled(sock, other)) {
1588
		UNIXCB(skb).pid  = get_pid(task_tgid(current));
1589
		current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1590 1591 1592
	}
}

1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621
static int maybe_init_creds(struct scm_cookie *scm,
			    struct socket *socket,
			    const struct sock *other)
{
	int err;
	struct msghdr msg = { .msg_controllen = 0 };

	err = scm_send(socket, &msg, scm, false);
	if (err)
		return err;

	if (unix_passcred_enabled(socket, other)) {
		scm->pid = get_pid(task_tgid(current));
		current_uid_gid(&scm->creds.uid, &scm->creds.gid);
	}
	return err;
}

static bool unix_skb_scm_eq(struct sk_buff *skb,
			    struct scm_cookie *scm)
{
	const struct unix_skb_parms *u = &UNIXCB(skb);

	return u->pid == scm->pid &&
	       uid_eq(u->uid, scm->creds.uid) &&
	       gid_eq(u->gid, scm->creds.gid) &&
	       unix_secdata_eq(scm, skb);
}

L
Linus Torvalds 已提交
1622 1623 1624 1625
/*
 *	Send AF_UNIX data.
 */

1626 1627
static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
			      size_t len)
L
Linus Torvalds 已提交
1628 1629
{
	struct sock *sk = sock->sk;
1630
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1631
	struct unix_sock *u = unix_sk(sk);
1632
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
L
Linus Torvalds 已提交
1633 1634 1635
	struct sock *other = NULL;
	int namelen = 0; /* fake GCC */
	int err;
1636
	unsigned int hash;
1637
	struct sk_buff *skb;
L
Linus Torvalds 已提交
1638
	long timeo;
C
Christoph Hellwig 已提交
1639
	struct scm_cookie scm;
E
Eric Dumazet 已提交
1640
	int max_level;
1641
	int data_len = 0;
1642
	int sk_locked;
L
Linus Torvalds 已提交
1643

1644
	wait_for_unix_gc();
C
Christoph Hellwig 已提交
1645
	err = scm_send(sock, msg, &scm, false);
L
Linus Torvalds 已提交
1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665
	if (err < 0)
		return err;

	err = -EOPNOTSUPP;
	if (msg->msg_flags&MSG_OOB)
		goto out;

	if (msg->msg_namelen) {
		err = unix_mkname(sunaddr, msg->msg_namelen, &hash);
		if (err < 0)
			goto out;
		namelen = err;
	} else {
		sunaddr = NULL;
		err = -ENOTCONN;
		other = unix_peer_get(sk);
		if (!other)
			goto out;
	}

1666 1667
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
	    && (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1668 1669 1670 1671 1672 1673
		goto out;

	err = -EMSGSIZE;
	if (len > sk->sk_sndbuf - 32)
		goto out;

1674
	if (len > SKB_MAX_ALLOC) {
1675 1676 1677
		data_len = min_t(size_t,
				 len - SKB_MAX_ALLOC,
				 MAX_SKB_FRAGS * PAGE_SIZE);
1678 1679 1680 1681
		data_len = PAGE_ALIGN(data_len);

		BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
	}
1682 1683

	skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1684 1685
				   msg->msg_flags & MSG_DONTWAIT, &err,
				   PAGE_ALLOC_COSTLY_ORDER);
1686
	if (skb == NULL)
L
Linus Torvalds 已提交
1687 1688
		goto out;

C
Christoph Hellwig 已提交
1689
	err = unix_scm_to_skb(&scm, skb, true);
E
Eric Dumazet 已提交
1690
	if (err < 0)
1691
		goto out_free;
E
Eric Dumazet 已提交
1692
	max_level = err + 1;
C
Catherine Zhang 已提交
1693

1694 1695 1696
	skb_put(skb, len - data_len);
	skb->data_len = data_len;
	skb->len = len;
A
Al Viro 已提交
1697
	err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
L
Linus Torvalds 已提交
1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708
	if (err)
		goto out_free;

	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);

restart:
	if (!other) {
		err = -ECONNRESET;
		if (sunaddr == NULL)
			goto out_free;

1709
		other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
L
Linus Torvalds 已提交
1710
					hash, &err);
1711
		if (other == NULL)
L
Linus Torvalds 已提交
1712 1713 1714
			goto out_free;
	}

A
Alban Crequy 已提交
1715 1716 1717 1718 1719 1720
	if (sk_filter(other, skb) < 0) {
		/* Toss the packet but do not return any error to the sender */
		err = len;
		goto out_free;
	}

1721
	sk_locked = 0;
1722
	unix_state_lock(other);
1723
restart_locked:
L
Linus Torvalds 已提交
1724 1725 1726 1727
	err = -EPERM;
	if (!unix_may_send(sk, other))
		goto out_unlock;

1728
	if (unlikely(sock_flag(other, SOCK_DEAD))) {
L
Linus Torvalds 已提交
1729 1730 1731 1732
		/*
		 *	Check with 1003.1g - what should
		 *	datagram error
		 */
1733
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1734 1735
		sock_put(other);

1736 1737 1738
		if (!sk_locked)
			unix_state_lock(sk);

L
Linus Torvalds 已提交
1739 1740
		err = 0;
		if (unix_peer(sk) == other) {
1741
			unix_peer(sk) = NULL;
1742 1743
			unix_dgram_peer_wake_disconnect_wakeup(sk, other);

1744
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1745 1746 1747 1748 1749

			unix_dgram_disconnected(sk, other);
			sock_put(other);
			err = -ECONNREFUSED;
		} else {
1750
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768
		}

		other = NULL;
		if (err)
			goto out_free;
		goto restart;
	}

	err = -EPIPE;
	if (other->sk_shutdown & RCV_SHUTDOWN)
		goto out_unlock;

	if (sk->sk_type != SOCK_SEQPACKET) {
		err = security_unix_may_send(sk->sk_socket, other->sk_socket);
		if (err)
			goto out_unlock;
	}

1769 1770 1771 1772 1773 1774
	/* other == sk && unix_peer(other) != sk if
	 * - unix_peer(sk) == NULL, destination address bound to sk
	 * - unix_peer(sk) == sk by time of get but disconnected before lock
	 */
	if (other != sk &&
	    unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
1775 1776 1777 1778 1779 1780 1781 1782
		if (timeo) {
			timeo = unix_wait_for_peer(other, timeo);

			err = sock_intr_errno(timeo);
			if (signal_pending(current))
				goto out_free;

			goto restart;
L
Linus Torvalds 已提交
1783 1784
		}

1785 1786 1787 1788
		if (!sk_locked) {
			unix_state_unlock(other);
			unix_state_double_lock(sk, other);
		}
L
Linus Torvalds 已提交
1789

1790 1791 1792 1793 1794 1795
		if (unix_peer(sk) != other ||
		    unix_dgram_peer_wake_me(sk, other)) {
			err = -EAGAIN;
			sk_locked = 1;
			goto out_unlock;
		}
L
Linus Torvalds 已提交
1796

1797 1798 1799 1800
		if (!sk_locked) {
			sk_locked = 1;
			goto restart_locked;
		}
L
Linus Torvalds 已提交
1801 1802
	}

1803 1804 1805
	if (unlikely(sk_locked))
		unix_state_unlock(sk);

1806 1807
	if (sock_flag(other, SOCK_RCVTSTAMP))
		__net_timestamp(skb);
1808
	maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1809
	skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1810 1811
	if (max_level > unix_sk(other)->recursion_level)
		unix_sk(other)->recursion_level = max_level;
1812
	unix_state_unlock(other);
1813
	other->sk_data_ready(other);
L
Linus Torvalds 已提交
1814
	sock_put(other);
C
Christoph Hellwig 已提交
1815
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1816 1817 1818
	return len;

out_unlock:
1819 1820
	if (sk_locked)
		unix_state_unlock(sk);
1821
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1822 1823 1824 1825 1826
out_free:
	kfree_skb(skb);
out:
	if (other)
		sock_put(other);
C
Christoph Hellwig 已提交
1827
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1828 1829 1830
	return err;
}

1831 1832 1833 1834
/* We use paged skbs for stream sockets, and limit occupancy to 32768
 * bytes, and a minimun of a full page.
 */
#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
1835

1836 1837
static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
			       size_t len)
L
Linus Torvalds 已提交
1838 1839 1840
{
	struct sock *sk = sock->sk;
	struct sock *other = NULL;
E
Eric Dumazet 已提交
1841
	int err, size;
1842
	struct sk_buff *skb;
1843
	int sent = 0;
C
Christoph Hellwig 已提交
1844
	struct scm_cookie scm;
1845
	bool fds_sent = false;
E
Eric Dumazet 已提交
1846
	int max_level;
1847
	int data_len;
L
Linus Torvalds 已提交
1848

1849
	wait_for_unix_gc();
C
Christoph Hellwig 已提交
1850
	err = scm_send(sock, msg, &scm, false);
L
Linus Torvalds 已提交
1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862
	if (err < 0)
		return err;

	err = -EOPNOTSUPP;
	if (msg->msg_flags&MSG_OOB)
		goto out_err;

	if (msg->msg_namelen) {
		err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
		goto out_err;
	} else {
		err = -ENOTCONN;
1863
		other = unix_peer(sk);
L
Linus Torvalds 已提交
1864 1865 1866 1867 1868 1869 1870
		if (!other)
			goto out_err;
	}

	if (sk->sk_shutdown & SEND_SHUTDOWN)
		goto pipe_err;

E
Eric Dumazet 已提交
1871
	while (sent < len) {
1872
		size = len - sent;
L
Linus Torvalds 已提交
1873 1874

		/* Keep two messages in the pipe so it schedules better */
1875
		size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
L
Linus Torvalds 已提交
1876

1877 1878
		/* allow fallback to order-0 allocations */
		size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1879

1880
		data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
L
Linus Torvalds 已提交
1881

1882 1883
		data_len = min_t(size_t, size, PAGE_ALIGN(data_len));

1884
		skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1885 1886
					   msg->msg_flags & MSG_DONTWAIT, &err,
					   get_order(UNIX_SKB_FRAGS_SZ));
1887
		if (!skb)
L
Linus Torvalds 已提交
1888 1889
			goto out_err;

1890
		/* Only send the fds in the first buffer */
C
Christoph Hellwig 已提交
1891
		err = unix_scm_to_skb(&scm, skb, !fds_sent);
E
Eric Dumazet 已提交
1892
		if (err < 0) {
1893
			kfree_skb(skb);
1894
			goto out_err;
1895
		}
E
Eric Dumazet 已提交
1896
		max_level = err + 1;
1897
		fds_sent = true;
L
Linus Torvalds 已提交
1898

1899 1900 1901
		skb_put(skb, size - data_len);
		skb->data_len = data_len;
		skb->len = size;
A
Al Viro 已提交
1902
		err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
E
Eric Dumazet 已提交
1903
		if (err) {
L
Linus Torvalds 已提交
1904
			kfree_skb(skb);
1905
			goto out_err;
L
Linus Torvalds 已提交
1906 1907
		}

1908
		unix_state_lock(other);
L
Linus Torvalds 已提交
1909 1910 1911 1912 1913

		if (sock_flag(other, SOCK_DEAD) ||
		    (other->sk_shutdown & RCV_SHUTDOWN))
			goto pipe_err_free;

1914
		maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1915
		skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1916 1917
		if (max_level > unix_sk(other)->recursion_level)
			unix_sk(other)->recursion_level = max_level;
1918
		unix_state_unlock(other);
1919
		other->sk_data_ready(other);
1920
		sent += size;
L
Linus Torvalds 已提交
1921 1922
	}

C
Christoph Hellwig 已提交
1923
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1924 1925 1926 1927

	return sent;

pipe_err_free:
1928
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1929 1930
	kfree_skb(skb);
pipe_err:
E
Eric Dumazet 已提交
1931 1932
	if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
L
Linus Torvalds 已提交
1933 1934
	err = -EPIPE;
out_err:
C
Christoph Hellwig 已提交
1935
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1936 1937 1938
	return sent ? : err;
}

1939 1940 1941
static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
				    int offset, size_t size, int flags)
{
1942 1943 1944 1945
	int err;
	bool send_sigpipe = false;
	bool init_scm = true;
	struct scm_cookie scm;
1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958
	struct sock *other, *sk = socket->sk;
	struct sk_buff *skb, *newskb = NULL, *tail = NULL;

	if (flags & MSG_OOB)
		return -EOPNOTSUPP;

	other = unix_peer(sk);
	if (!other || sk->sk_state != TCP_ESTABLISHED)
		return -ENOTCONN;

	if (false) {
alloc_skb:
		unix_state_unlock(other);
1959
		mutex_unlock(&unix_sk(other)->iolock);
1960 1961 1962
		newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
					      &err, 0);
		if (!newskb)
1963
			goto err;
1964 1965
	}

1966
	/* we must acquire iolock as we modify already present
1967 1968
	 * skbs in the sk_receive_queue and mess with skb->len
	 */
1969
	err = mutex_lock_interruptible(&unix_sk(other)->iolock);
1970 1971 1972 1973 1974 1975 1976
	if (err) {
		err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
		goto err;
	}

	if (sk->sk_shutdown & SEND_SHUTDOWN) {
		err = -EPIPE;
1977
		send_sigpipe = true;
1978 1979 1980 1981 1982 1983 1984 1985
		goto err_unlock;
	}

	unix_state_lock(other);

	if (sock_flag(other, SOCK_DEAD) ||
	    other->sk_shutdown & RCV_SHUTDOWN) {
		err = -EPIPE;
1986
		send_sigpipe = true;
1987 1988 1989
		goto err_state_unlock;
	}

1990 1991 1992 1993 1994 1995 1996
	if (init_scm) {
		err = maybe_init_creds(&scm, socket, other);
		if (err)
			goto err_state_unlock;
		init_scm = false;
	}

1997 1998 1999
	skb = skb_peek_tail(&other->sk_receive_queue);
	if (tail && tail == skb) {
		skb = newskb;
2000 2001
	} else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
		if (newskb) {
2002
			skb = newskb;
2003 2004
		} else {
			tail = skb;
2005
			goto alloc_skb;
2006
		}
2007 2008 2009 2010 2011 2012
	} else if (newskb) {
		/* this is fast path, we don't necessarily need to
		 * call to kfree_skb even though with newskb == NULL
		 * this - does no harm
		 */
		consume_skb(newskb);
2013
		newskb = NULL;
2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025
	}

	if (skb_append_pagefrags(skb, page, offset, size)) {
		tail = skb;
		goto alloc_skb;
	}

	skb->len += size;
	skb->data_len += size;
	skb->truesize += size;
	atomic_add(size, &sk->sk_wmem_alloc);

2026
	if (newskb) {
2027 2028 2029
		err = unix_scm_to_skb(&scm, skb, false);
		if (err)
			goto err_state_unlock;
2030
		spin_lock(&other->sk_receive_queue.lock);
2031
		__skb_queue_tail(&other->sk_receive_queue, newskb);
2032 2033
		spin_unlock(&other->sk_receive_queue.lock);
	}
2034 2035

	unix_state_unlock(other);
2036
	mutex_unlock(&unix_sk(other)->iolock);
2037 2038

	other->sk_data_ready(other);
2039
	scm_destroy(&scm);
2040 2041 2042 2043 2044
	return size;

err_state_unlock:
	unix_state_unlock(other);
err_unlock:
2045
	mutex_unlock(&unix_sk(other)->iolock);
2046 2047 2048 2049
err:
	kfree_skb(newskb);
	if (send_sigpipe && !(flags & MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
2050 2051
	if (!init_scm)
		scm_destroy(&scm);
2052 2053 2054
	return err;
}

2055 2056
static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
				  size_t len)
L
Linus Torvalds 已提交
2057 2058 2059
{
	int err;
	struct sock *sk = sock->sk;
2060

L
Linus Torvalds 已提交
2061 2062 2063 2064 2065 2066 2067 2068 2069 2070
	err = sock_error(sk);
	if (err)
		return err;

	if (sk->sk_state != TCP_ESTABLISHED)
		return -ENOTCONN;

	if (msg->msg_namelen)
		msg->msg_namelen = 0;

2071
	return unix_dgram_sendmsg(sock, msg, len);
L
Linus Torvalds 已提交
2072
}
2073

2074 2075
static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
				  size_t size, int flags)
2076 2077 2078 2079 2080 2081
{
	struct sock *sk = sock->sk;

	if (sk->sk_state != TCP_ESTABLISHED)
		return -ENOTCONN;

2082
	return unix_dgram_recvmsg(sock, msg, size, flags);
2083 2084
}

L
Linus Torvalds 已提交
2085 2086 2087 2088 2089 2090 2091 2092 2093 2094
static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
{
	struct unix_sock *u = unix_sk(sk);

	if (u->addr) {
		msg->msg_namelen = u->addr->len;
		memcpy(msg->msg_name, u->addr->name, u->addr->len);
	}
}

2095 2096
static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
			      size_t size, int flags)
L
Linus Torvalds 已提交
2097
{
C
Christoph Hellwig 已提交
2098
	struct scm_cookie scm;
L
Linus Torvalds 已提交
2099 2100
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
2101 2102
	struct sk_buff *skb, *last;
	long timeo;
L
Linus Torvalds 已提交
2103
	int err;
2104
	int peeked, skip;
L
Linus Torvalds 已提交
2105 2106 2107 2108 2109

	err = -EOPNOTSUPP;
	if (flags&MSG_OOB)
		goto out;

2110
	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
L
Linus Torvalds 已提交
2111

2112
	do {
2113
		mutex_lock(&u->iolock);
2114

2115
		skip = sk_peek_offset(sk, flags);
2116 2117
		skb = __skb_try_recv_datagram(sk, flags, NULL, &peeked, &skip,
					      &err, &last);
2118 2119 2120
		if (skb)
			break;

2121
		mutex_unlock(&u->iolock);
2122 2123 2124 2125 2126 2127

		if (err != -EAGAIN)
			break;
	} while (timeo &&
		 !__skb_wait_for_more_packets(sk, &err, &timeo, last));

2128
	if (!skb) { /* implies iolock unlocked */
2129 2130 2131 2132 2133 2134
		unix_state_lock(sk);
		/* Signal EOF on disconnected non-blocking SEQPACKET socket. */
		if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN &&
		    (sk->sk_shutdown & RCV_SHUTDOWN))
			err = 0;
		unix_state_unlock(sk);
2135
		goto out;
2136
	}
L
Linus Torvalds 已提交
2137

2138 2139 2140 2141
	if (wq_has_sleeper(&u->peer_wait))
		wake_up_interruptible_sync_poll(&u->peer_wait,
						POLLOUT | POLLWRNORM |
						POLLWRBAND);
L
Linus Torvalds 已提交
2142 2143 2144 2145

	if (msg->msg_name)
		unix_copy_addr(msg, skb->sk);

2146 2147 2148
	if (size > skb->len - skip)
		size = skb->len - skip;
	else if (size < skb->len - skip)
L
Linus Torvalds 已提交
2149 2150
		msg->msg_flags |= MSG_TRUNC;

2151
	err = skb_copy_datagram_msg(skb, skip, msg, size);
L
Linus Torvalds 已提交
2152 2153 2154
	if (err)
		goto out_free;

2155 2156 2157
	if (sock_flag(sk, SOCK_RCVTSTAMP))
		__sock_recv_timestamp(msg, sk, skb);

C
Christoph Hellwig 已提交
2158 2159 2160 2161
	memset(&scm, 0, sizeof(scm));

	scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
	unix_set_secdata(&scm, skb);
L
Linus Torvalds 已提交
2162

E
Eric Dumazet 已提交
2163
	if (!(flags & MSG_PEEK)) {
L
Linus Torvalds 已提交
2164
		if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
2165
			unix_detach_fds(&scm, skb);
2166 2167

		sk_peek_offset_bwd(sk, skb->len);
E
Eric Dumazet 已提交
2168
	} else {
L
Linus Torvalds 已提交
2169 2170 2171 2172 2173 2174
		/* It is questionable: on PEEK we could:
		   - do not return fds - good, but too simple 8)
		   - return fds, and do not return them on read (old strategy,
		     apparently wrong)
		   - clone fds (I chose it for now, it is the most universal
		     solution)
2175 2176 2177 2178 2179

		   POSIX 1003.1g does not actually define this clearly
		   at all. POSIX 1003.1g doesn't define a lot of things
		   clearly however!

L
Linus Torvalds 已提交
2180
		*/
2181 2182 2183

		sk_peek_offset_fwd(sk, size);

L
Linus Torvalds 已提交
2184
		if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
2185
			scm.fp = scm_fp_dup(UNIXCB(skb).fp);
L
Linus Torvalds 已提交
2186
	}
2187
	err = (flags & MSG_TRUNC) ? skb->len - skip : size;
L
Linus Torvalds 已提交
2188

C
Christoph Hellwig 已提交
2189
	scm_recv(sock, msg, &scm, flags);
L
Linus Torvalds 已提交
2190 2191

out_free:
E
Eric Dumazet 已提交
2192
	skb_free_datagram(sk, skb);
2193
	mutex_unlock(&u->iolock);
L
Linus Torvalds 已提交
2194 2195 2196 2197 2198
out:
	return err;
}

/*
2199
 *	Sleep until more data has arrived. But check for races..
L
Linus Torvalds 已提交
2200
 */
2201
static long unix_stream_data_wait(struct sock *sk, long timeo,
2202 2203
				  struct sk_buff *last, unsigned int last_len,
				  bool freezable)
L
Linus Torvalds 已提交
2204
{
2205
	struct sk_buff *tail;
L
Linus Torvalds 已提交
2206 2207
	DEFINE_WAIT(wait);

2208
	unix_state_lock(sk);
L
Linus Torvalds 已提交
2209 2210

	for (;;) {
E
Eric Dumazet 已提交
2211
		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
L
Linus Torvalds 已提交
2212

2213 2214 2215
		tail = skb_peek_tail(&sk->sk_receive_queue);
		if (tail != last ||
		    (tail && tail->len != last_len) ||
L
Linus Torvalds 已提交
2216 2217 2218 2219 2220 2221
		    sk->sk_err ||
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
		    signal_pending(current) ||
		    !timeo)
			break;

2222
		sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2223
		unix_state_unlock(sk);
2224 2225 2226 2227
		if (freezable)
			timeo = freezable_schedule_timeout(timeo);
		else
			timeo = schedule_timeout(timeo);
2228
		unix_state_lock(sk);
2229 2230 2231 2232

		if (sock_flag(sk, SOCK_DEAD))
			break;

2233
		sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
L
Linus Torvalds 已提交
2234 2235
	}

E
Eric Dumazet 已提交
2236
	finish_wait(sk_sleep(sk), &wait);
2237
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
2238 2239 2240
	return timeo;
}

2241 2242 2243 2244 2245
static unsigned int unix_skb_len(const struct sk_buff *skb)
{
	return skb->len - UNIXCB(skb).consumed;
}

2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256
struct unix_stream_read_state {
	int (*recv_actor)(struct sk_buff *, int, int,
			  struct unix_stream_read_state *);
	struct socket *socket;
	struct msghdr *msg;
	struct pipe_inode_info *pipe;
	size_t size;
	int flags;
	unsigned int splice_flags;
};

2257 2258
static int unix_stream_read_generic(struct unix_stream_read_state *state,
				    bool freezable)
L
Linus Torvalds 已提交
2259
{
C
Christoph Hellwig 已提交
2260
	struct scm_cookie scm;
2261
	struct socket *sock = state->socket;
L
Linus Torvalds 已提交
2262 2263 2264
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
	int copied = 0;
2265
	int flags = state->flags;
2266
	int noblock = flags & MSG_DONTWAIT;
2267
	bool check_creds = false;
L
Linus Torvalds 已提交
2268 2269 2270
	int target;
	int err = 0;
	long timeo;
2271
	int skip;
2272 2273
	size_t size = state->size;
	unsigned int last_len;
L
Linus Torvalds 已提交
2274

2275 2276
	if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
		err = -EINVAL;
L
Linus Torvalds 已提交
2277
		goto out;
2278
	}
L
Linus Torvalds 已提交
2279

2280 2281
	if (unlikely(flags & MSG_OOB)) {
		err = -EOPNOTSUPP;
L
Linus Torvalds 已提交
2282
		goto out;
2283
	}
L
Linus Torvalds 已提交
2284

2285
	target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2286
	timeo = sock_rcvtimeo(sk, noblock);
L
Linus Torvalds 已提交
2287

2288 2289
	memset(&scm, 0, sizeof(scm));

L
Linus Torvalds 已提交
2290 2291 2292
	/* Lock the socket to prevent queue disordering
	 * while sleeps in memcpy_tomsg
	 */
2293
	mutex_lock(&u->iolock);
L
Linus Torvalds 已提交
2294

2295 2296 2297 2298 2299
	if (flags & MSG_PEEK)
		skip = sk_peek_offset(sk, flags);
	else
		skip = 0;

E
Eric Dumazet 已提交
2300
	do {
L
Linus Torvalds 已提交
2301
		int chunk;
2302
		bool drop_skb;
2303
		struct sk_buff *skb, *last;
L
Linus Torvalds 已提交
2304

2305
redo:
2306
		unix_state_lock(sk);
2307 2308 2309 2310
		if (sock_flag(sk, SOCK_DEAD)) {
			err = -ECONNRESET;
			goto unlock;
		}
2311
		last = skb = skb_peek(&sk->sk_receive_queue);
2312
		last_len = last ? last->len : 0;
2313
again:
E
Eric Dumazet 已提交
2314
		if (skb == NULL) {
E
Eric Dumazet 已提交
2315
			unix_sk(sk)->recursion_level = 0;
L
Linus Torvalds 已提交
2316
			if (copied >= target)
2317
				goto unlock;
L
Linus Torvalds 已提交
2318 2319 2320 2321

			/*
			 *	POSIX 1003.1g mandates this order.
			 */
2322

E
Eric Dumazet 已提交
2323 2324
			err = sock_error(sk);
			if (err)
2325
				goto unlock;
L
Linus Torvalds 已提交
2326
			if (sk->sk_shutdown & RCV_SHUTDOWN)
2327 2328 2329
				goto unlock;

			unix_state_unlock(sk);
2330 2331
			if (!timeo) {
				err = -EAGAIN;
L
Linus Torvalds 已提交
2332
				break;
2333 2334
			}

2335
			mutex_unlock(&u->iolock);
L
Linus Torvalds 已提交
2336

2337
			timeo = unix_stream_data_wait(sk, timeo, last,
2338
						      last_len, freezable);
L
Linus Torvalds 已提交
2339

2340
			if (signal_pending(current)) {
L
Linus Torvalds 已提交
2341
				err = sock_intr_errno(timeo);
2342
				scm_destroy(&scm);
L
Linus Torvalds 已提交
2343 2344
				goto out;
			}
2345

2346
			mutex_lock(&u->iolock);
2347
			goto redo;
2348
unlock:
2349 2350
			unix_state_unlock(sk);
			break;
L
Linus Torvalds 已提交
2351
		}
2352

2353 2354
		while (skip >= unix_skb_len(skb)) {
			skip -= unix_skb_len(skb);
2355
			last = skb;
2356
			last_len = skb->len;
2357
			skb = skb_peek_next(skb, &sk->sk_receive_queue);
2358 2359
			if (!skb)
				goto again;
2360 2361
		}

2362
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
2363 2364 2365

		if (check_creds) {
			/* Never glue messages from different writers */
2366
			if (!unix_skb_scm_eq(skb, &scm))
L
Linus Torvalds 已提交
2367
				break;
2368
		} else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
L
Linus Torvalds 已提交
2369
			/* Copy credentials */
C
Christoph Hellwig 已提交
2370
			scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2371
			unix_set_secdata(&scm, skb);
2372
			check_creds = true;
L
Linus Torvalds 已提交
2373 2374 2375
		}

		/* Copy address just once */
2376 2377 2378 2379
		if (state->msg && state->msg->msg_name) {
			DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
					 state->msg->msg_name);
			unix_copy_addr(state->msg, skb->sk);
L
Linus Torvalds 已提交
2380 2381 2382
			sunaddr = NULL;
		}

2383
		chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2384
		skb_get(skb);
2385
		chunk = state->recv_actor(skb, skip, chunk, state);
2386 2387 2388
		drop_skb = !unix_skb_len(skb);
		/* skb is only safe to use if !drop_skb */
		consume_skb(skb);
2389
		if (chunk < 0) {
L
Linus Torvalds 已提交
2390 2391 2392 2393 2394 2395 2396
			if (copied == 0)
				copied = -EFAULT;
			break;
		}
		copied += chunk;
		size -= chunk;

2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408
		if (drop_skb) {
			/* the skb was touched by a concurrent reader;
			 * we should not expect anything from this skb
			 * anymore and assume it invalid - we can be
			 * sure it was dropped from the socket queue
			 *
			 * let's report a short read
			 */
			err = 0;
			break;
		}

L
Linus Torvalds 已提交
2409
		/* Mark read part of skb as used */
E
Eric Dumazet 已提交
2410
		if (!(flags & MSG_PEEK)) {
2411
			UNIXCB(skb).consumed += chunk;
L
Linus Torvalds 已提交
2412

2413 2414
			sk_peek_offset_bwd(sk, chunk);

L
Linus Torvalds 已提交
2415
			if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
2416
				unix_detach_fds(&scm, skb);
L
Linus Torvalds 已提交
2417

2418
			if (unix_skb_len(skb))
L
Linus Torvalds 已提交
2419 2420
				break;

2421
			skb_unlink(skb, &sk->sk_receive_queue);
2422
			consume_skb(skb);
L
Linus Torvalds 已提交
2423

C
Christoph Hellwig 已提交
2424
			if (scm.fp)
L
Linus Torvalds 已提交
2425
				break;
E
Eric Dumazet 已提交
2426
		} else {
L
Linus Torvalds 已提交
2427 2428 2429
			/* It is questionable, see note in unix_dgram_recvmsg.
			 */
			if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
2430
				scm.fp = scm_fp_dup(UNIXCB(skb).fp);
L
Linus Torvalds 已提交
2431

2432
			sk_peek_offset_fwd(sk, chunk);
2433

2434 2435 2436
			if (UNIXCB(skb).fp)
				break;

2437
			skip = 0;
2438 2439 2440 2441 2442 2443 2444
			last = skb;
			last_len = skb->len;
			unix_state_lock(sk);
			skb = skb_peek_next(skb, &sk->sk_receive_queue);
			if (skb)
				goto again;
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
2445 2446 2447 2448
			break;
		}
	} while (size);

2449
	mutex_unlock(&u->iolock);
2450 2451 2452 2453
	if (state->msg)
		scm_recv(sock, state->msg, &scm, flags);
	else
		scm_destroy(&scm);
L
Linus Torvalds 已提交
2454 2455 2456 2457
out:
	return copied ? : err;
}

2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479
static int unix_stream_read_actor(struct sk_buff *skb,
				  int skip, int chunk,
				  struct unix_stream_read_state *state)
{
	int ret;

	ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
				    state->msg, chunk);
	return ret ?: chunk;
}

static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
			       size_t size, int flags)
{
	struct unix_stream_read_state state = {
		.recv_actor = unix_stream_read_actor,
		.socket = sock,
		.msg = msg,
		.size = size,
		.flags = flags
	};

2480
	return unix_stream_read_generic(&state, true);
2481 2482 2483 2484 2485 2486 2487 2488
}

static int unix_stream_splice_actor(struct sk_buff *skb,
				    int skip, int chunk,
				    struct unix_stream_read_state *state)
{
	return skb_splice_bits(skb, state->socket->sk,
			       UNIXCB(skb).consumed + skip,
A
Al Viro 已提交
2489
			       state->pipe, chunk, state->splice_flags);
2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510
}

static ssize_t unix_stream_splice_read(struct socket *sock,  loff_t *ppos,
				       struct pipe_inode_info *pipe,
				       size_t size, unsigned int flags)
{
	struct unix_stream_read_state state = {
		.recv_actor = unix_stream_splice_actor,
		.socket = sock,
		.pipe = pipe,
		.size = size,
		.splice_flags = flags,
	};

	if (unlikely(*ppos))
		return -ESPIPE;

	if (sock->file->f_flags & O_NONBLOCK ||
	    flags & SPLICE_F_NONBLOCK)
		state.flags = MSG_DONTWAIT;

2511
	return unix_stream_read_generic(&state, false);
2512 2513
}

L
Linus Torvalds 已提交
2514 2515 2516 2517 2518
static int unix_shutdown(struct socket *sock, int mode)
{
	struct sock *sk = sock->sk;
	struct sock *other;

2519 2520 2521 2522 2523 2524 2525 2526
	if (mode < SHUT_RD || mode > SHUT_RDWR)
		return -EINVAL;
	/* This maps:
	 * SHUT_RD   (0) -> RCV_SHUTDOWN  (1)
	 * SHUT_WR   (1) -> SEND_SHUTDOWN (2)
	 * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
	 */
	++mode;
2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552

	unix_state_lock(sk);
	sk->sk_shutdown |= mode;
	other = unix_peer(sk);
	if (other)
		sock_hold(other);
	unix_state_unlock(sk);
	sk->sk_state_change(sk);

	if (other &&
		(sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) {

		int peer_mode = 0;

		if (mode&RCV_SHUTDOWN)
			peer_mode |= SEND_SHUTDOWN;
		if (mode&SEND_SHUTDOWN)
			peer_mode |= RCV_SHUTDOWN;
		unix_state_lock(other);
		other->sk_shutdown |= peer_mode;
		unix_state_unlock(other);
		other->sk_state_change(other);
		if (peer_mode == SHUTDOWN_MASK)
			sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
		else if (peer_mode & RCV_SHUTDOWN)
			sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
L
Linus Torvalds 已提交
2553
	}
2554 2555 2556
	if (other)
		sock_put(other);

L
Linus Torvalds 已提交
2557 2558 2559
	return 0;
}

2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571
long unix_inq_len(struct sock *sk)
{
	struct sk_buff *skb;
	long amount = 0;

	if (sk->sk_state == TCP_LISTEN)
		return -EINVAL;

	spin_lock(&sk->sk_receive_queue.lock);
	if (sk->sk_type == SOCK_STREAM ||
	    sk->sk_type == SOCK_SEQPACKET) {
		skb_queue_walk(&sk->sk_receive_queue, skb)
2572
			amount += unix_skb_len(skb);
2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589
	} else {
		skb = skb_peek(&sk->sk_receive_queue);
		if (skb)
			amount = skb->len;
	}
	spin_unlock(&sk->sk_receive_queue.lock);

	return amount;
}
EXPORT_SYMBOL_GPL(unix_inq_len);

long unix_outq_len(struct sock *sk)
{
	return sk_wmem_alloc_get(sk);
}
EXPORT_SYMBOL_GPL(unix_outq_len);

L
Linus Torvalds 已提交
2590 2591 2592
static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	struct sock *sk = sock->sk;
2593
	long amount = 0;
L
Linus Torvalds 已提交
2594 2595
	int err;

E
Eric Dumazet 已提交
2596 2597
	switch (cmd) {
	case SIOCOUTQ:
2598
		amount = unix_outq_len(sk);
E
Eric Dumazet 已提交
2599 2600 2601
		err = put_user(amount, (int __user *)arg);
		break;
	case SIOCINQ:
2602 2603 2604 2605
		amount = unix_inq_len(sk);
		if (amount < 0)
			err = amount;
		else
L
Linus Torvalds 已提交
2606
			err = put_user(amount, (int __user *)arg);
2607
		break;
E
Eric Dumazet 已提交
2608 2609 2610
	default:
		err = -ENOIOCTLCMD;
		break;
L
Linus Torvalds 已提交
2611 2612 2613 2614
	}
	return err;
}

E
Eric Dumazet 已提交
2615
static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
L
Linus Torvalds 已提交
2616 2617 2618 2619
{
	struct sock *sk = sock->sk;
	unsigned int mask;

E
Eric Dumazet 已提交
2620
	sock_poll_wait(file, sk_sleep(sk), wait);
L
Linus Torvalds 已提交
2621 2622 2623 2624 2625 2626 2627
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err)
		mask |= POLLERR;
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;
2628
	if (sk->sk_shutdown & RCV_SHUTDOWN)
E
Eric Dumazet 已提交
2629
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
L
Linus Torvalds 已提交
2630 2631

	/* readable? */
E
Eric Dumazet 已提交
2632
	if (!skb_queue_empty(&sk->sk_receive_queue))
L
Linus Torvalds 已提交
2633 2634 2635
		mask |= POLLIN | POLLRDNORM;

	/* Connection-based need to check for termination and startup */
E
Eric Dumazet 已提交
2636 2637
	if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
	    sk->sk_state == TCP_CLOSE)
L
Linus Torvalds 已提交
2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649
		mask |= POLLHUP;

	/*
	 * we set writable also when the other side has shut down the
	 * connection. This prevents stuck sockets.
	 */
	if (unix_writable(sk))
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;

	return mask;
}

2650 2651
static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
				    poll_table *wait)
2652
{
2653 2654
	struct sock *sk = sock->sk, *other;
	unsigned int mask, writable;
2655

E
Eric Dumazet 已提交
2656
	sock_poll_wait(file, sk_sleep(sk), wait);
2657 2658 2659 2660
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2661
		mask |= POLLERR |
2662
			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2663

2664
	if (sk->sk_shutdown & RCV_SHUTDOWN)
2665
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2666 2667 2668 2669
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;

	/* readable? */
2670
	if (!skb_queue_empty(&sk->sk_receive_queue))
2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681
		mask |= POLLIN | POLLRDNORM;

	/* Connection-based need to check for termination and startup */
	if (sk->sk_type == SOCK_SEQPACKET) {
		if (sk->sk_state == TCP_CLOSE)
			mask |= POLLHUP;
		/* connection hasn't started yet? */
		if (sk->sk_state == TCP_SYN_SENT)
			return mask;
	}

E
Eric Dumazet 已提交
2682
	/* No write status requested, avoid expensive OUT tests. */
2683
	if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
E
Eric Dumazet 已提交
2684 2685
		return mask;

2686
	writable = unix_writable(sk);
2687 2688 2689 2690 2691 2692 2693 2694 2695 2696
	if (writable) {
		unix_state_lock(sk);

		other = unix_peer(sk);
		if (other && unix_peer(other) != sk &&
		    unix_recvq_full(other) &&
		    unix_dgram_peer_wake_me(sk, other))
			writable = 0;

		unix_state_unlock(sk);
2697 2698 2699
	}

	if (writable)
2700 2701
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
	else
2702
		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2703 2704 2705

	return mask;
}
L
Linus Torvalds 已提交
2706 2707

#ifdef CONFIG_PROC_FS
2708

E
Eric Dumazet 已提交
2709 2710 2711 2712 2713
#define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1)

#define get_bucket(x) ((x) >> BUCKET_SPACE)
#define get_offset(x) ((x) & ((1L << BUCKET_SPACE) - 1))
#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))
2714

E
Eric Dumazet 已提交
2715
static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
L
Linus Torvalds 已提交
2716
{
E
Eric Dumazet 已提交
2717 2718 2719 2720
	unsigned long offset = get_offset(*pos);
	unsigned long bucket = get_bucket(*pos);
	struct sock *sk;
	unsigned long count = 0;
L
Linus Torvalds 已提交
2721

E
Eric Dumazet 已提交
2722 2723
	for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
		if (sock_net(sk) != seq_file_net(seq))
2724
			continue;
E
Eric Dumazet 已提交
2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743
		if (++count == offset)
			break;
	}

	return sk;
}

static struct sock *unix_next_socket(struct seq_file *seq,
				     struct sock *sk,
				     loff_t *pos)
{
	unsigned long bucket;

	while (sk > (struct sock *)SEQ_START_TOKEN) {
		sk = sk_next(sk);
		if (!sk)
			goto next_bucket;
		if (sock_net(sk) == seq_file_net(seq))
			return sk;
L
Linus Torvalds 已提交
2744
	}
E
Eric Dumazet 已提交
2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755

	do {
		sk = unix_from_bucket(seq, pos);
		if (sk)
			return sk;

next_bucket:
		bucket = get_bucket(*pos) + 1;
		*pos = set_bucket_offset(bucket, 1);
	} while (bucket < ARRAY_SIZE(unix_socket_table));

L
Linus Torvalds 已提交
2756 2757 2758 2759
	return NULL;
}

static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2760
	__acquires(unix_table_lock)
L
Linus Torvalds 已提交
2761
{
2762
	spin_lock(&unix_table_lock);
E
Eric Dumazet 已提交
2763 2764 2765 2766 2767 2768 2769 2770

	if (!*pos)
		return SEQ_START_TOKEN;

	if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
		return NULL;

	return unix_next_socket(seq, NULL, pos);
L
Linus Torvalds 已提交
2771 2772 2773 2774 2775
}

static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	++*pos;
E
Eric Dumazet 已提交
2776
	return unix_next_socket(seq, v, pos);
L
Linus Torvalds 已提交
2777 2778 2779
}

static void unix_seq_stop(struct seq_file *seq, void *v)
2780
	__releases(unix_table_lock)
L
Linus Torvalds 已提交
2781
{
2782
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
2783 2784 2785 2786
}

static int unix_seq_show(struct seq_file *seq, void *v)
{
2787

J
Joe Perches 已提交
2788
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
2789 2790 2791 2792 2793
		seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
			 "Inode Path\n");
	else {
		struct sock *s = v;
		struct unix_sock *u = unix_sk(s);
2794
		unix_state_lock(s);
L
Linus Torvalds 已提交
2795

D
Dan Rosenberg 已提交
2796
		seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
L
Linus Torvalds 已提交
2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819
			s,
			atomic_read(&s->sk_refcnt),
			0,
			s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
			s->sk_type,
			s->sk_socket ?
			(s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
			(s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
			sock_i_ino(s));

		if (u->addr) {
			int i, len;
			seq_putc(seq, ' ');

			i = 0;
			len = u->addr->len - sizeof(short);
			if (!UNIX_ABSTRACT(s))
				len--;
			else {
				seq_putc(seq, '@');
				i++;
			}
			for ( ; i < len; i++)
2820 2821
				seq_putc(seq, u->addr->name->sun_path[i] ?:
					 '@');
L
Linus Torvalds 已提交
2822
		}
2823
		unix_state_unlock(s);
L
Linus Torvalds 已提交
2824 2825 2826 2827 2828 2829
		seq_putc(seq, '\n');
	}

	return 0;
}

2830
static const struct seq_operations unix_seq_ops = {
L
Linus Torvalds 已提交
2831 2832 2833 2834 2835 2836 2837 2838
	.start  = unix_seq_start,
	.next   = unix_seq_next,
	.stop   = unix_seq_stop,
	.show   = unix_seq_show,
};

static int unix_seq_open(struct inode *inode, struct file *file)
{
2839
	return seq_open_net(inode, file, &unix_seq_ops,
E
Eric Dumazet 已提交
2840
			    sizeof(struct seq_net_private));
L
Linus Torvalds 已提交
2841 2842
}

2843
static const struct file_operations unix_seq_fops = {
L
Linus Torvalds 已提交
2844 2845 2846 2847
	.owner		= THIS_MODULE,
	.open		= unix_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
2848
	.release	= seq_release_net,
L
Linus Torvalds 已提交
2849 2850 2851 2852
};

#endif

2853
static const struct net_proto_family unix_family_ops = {
L
Linus Torvalds 已提交
2854 2855 2856 2857 2858
	.family = PF_UNIX,
	.create = unix_create,
	.owner	= THIS_MODULE,
};

2859

2860
static int __net_init unix_net_init(struct net *net)
2861 2862 2863
{
	int error = -ENOMEM;

2864
	net->unx.sysctl_max_dgram_qlen = 10;
2865 2866
	if (unix_sysctl_register(net))
		goto out;
2867

2868
#ifdef CONFIG_PROC_FS
2869
	if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2870
		unix_sysctl_unregister(net);
2871
		goto out;
2872
	}
2873 2874 2875
#endif
	error = 0;
out:
2876
	return error;
2877 2878
}

2879
static void __net_exit unix_net_exit(struct net *net)
2880
{
2881
	unix_sysctl_unregister(net);
2882
	remove_proc_entry("unix", net->proc_net);
2883 2884 2885 2886 2887 2888 2889
}

static struct pernet_operations unix_net_ops = {
	.init = unix_net_init,
	.exit = unix_net_exit,
};

L
Linus Torvalds 已提交
2890 2891 2892 2893
static int __init af_unix_init(void)
{
	int rc = -1;

2894
	BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
L
Linus Torvalds 已提交
2895 2896

	rc = proto_register(&unix_proto, 1);
2897
	if (rc != 0) {
W
wangweidong 已提交
2898
		pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
L
Linus Torvalds 已提交
2899 2900 2901 2902
		goto out;
	}

	sock_register(&unix_family_ops);
2903
	register_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2904 2905 2906 2907 2908 2909 2910 2911
out:
	return rc;
}

static void __exit af_unix_exit(void)
{
	sock_unregister(PF_UNIX);
	proto_unregister(&unix_proto);
2912
	unregister_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2913 2914
}

2915 2916 2917 2918 2919
/* Earlier than device_initcall() so that other drivers invoking
   request_module() don't end up in a loop when modprobe tries
   to use a UNIX socket. But later than subsys_initcall() because
   we depend on stuff initialised there */
fs_initcall(af_unix_init);
L
Linus Torvalds 已提交
2920 2921 2922 2923
module_exit(af_unix_exit);

MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_UNIX);