af_unix.c 67.9 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>
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#include <linux/sched/signal.h>
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#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>
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#include <linux/uaccess.h>
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#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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#include <linux/file.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)
{
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	if (refcount_dec_and_test(&addr->refcnt))
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		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
 *
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 * In order to propagate a wake up, a wait_queue_entry_t of the client
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 * 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.
 */

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static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
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				      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 &&
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	       (refcount_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(refcount_read(&sk->sk_wmem_alloc));
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	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) {
556
		if (state == TCP_LISTEN)
L
Linus Torvalds 已提交
557 558
			unix_release_sock(skb->sk, 1);
		/* passed fds are erased in the kfree_skb hook	      */
559
		UNIXCB(skb).consumed = skb->len;
L
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560 561 562
		kfree_skb(skb);
	}

A
Al Viro 已提交
563 564
	if (path.dentry)
		path_put(&path);
L
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565 566 567 568 569 570

	sock_put(sk);

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

	/*
A
Alan Cox 已提交
571
	 * Fixme: BSD difference: In BSD all sockets connected to us get
L
Linus Torvalds 已提交
572 573 574 575 576 577 578 579 580
	 *	  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)
	 */

581
	if (unix_tot_inflight)
582
		unix_gc();		/* Garbage collect fds */
L
Linus Torvalds 已提交
583 584
}

585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602
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
Linus Torvalds 已提交
603 604 605 606 607
static int unix_listen(struct socket *sock, int backlog)
{
	int err;
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
608
	struct pid *old_pid = NULL;
L
Linus Torvalds 已提交
609 610

	err = -EOPNOTSUPP;
E
Eric Dumazet 已提交
611 612
	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
		goto out;	/* Only stream/seqpacket sockets accept */
L
Linus Torvalds 已提交
613 614
	err = -EINVAL;
	if (!u->addr)
E
Eric Dumazet 已提交
615
		goto out;	/* No listens on an unbound socket */
616
	unix_state_lock(sk);
L
Linus Torvalds 已提交
617 618 619 620 621 622 623
	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 */
624
	init_peercred(sk);
L
Linus Torvalds 已提交
625 626 627
	err = 0;

out_unlock:
628
	unix_state_unlock(sk);
629
	put_pid(old_pid);
L
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630 631 632 633 634 635 636 637 638
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 *);
639
static int unix_accept(struct socket *, struct socket *, int, bool);
L
Linus Torvalds 已提交
640 641
static int unix_getname(struct socket *, struct sockaddr *, int *, int);
static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
642 643
static unsigned int unix_dgram_poll(struct file *, struct socket *,
				    poll_table *);
L
Linus Torvalds 已提交
644 645
static int unix_ioctl(struct socket *, unsigned int, unsigned long);
static int unix_shutdown(struct socket *, int);
646 647
static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
648 649
static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
				    size_t size, int flags);
650 651 652
static ssize_t unix_stream_splice_read(struct socket *,  loff_t *ppos,
				       struct pipe_inode_info *, size_t size,
				       unsigned int flags);
653 654
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
655 656
static int unix_dgram_connect(struct socket *, struct sockaddr *,
			      int, int);
657 658 659
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
660

661
static int unix_set_peek_off(struct sock *sk, int val)
662 663 664
{
	struct unix_sock *u = unix_sk(sk);

665
	if (mutex_lock_interruptible(&u->iolock))
666 667
		return -EINTR;

668
	sk->sk_peek_off = val;
669
	mutex_unlock(&u->iolock);
670 671

	return 0;
672 673 674
}


675
static const struct proto_ops unix_stream_ops = {
L
Linus Torvalds 已提交
676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692
	.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,
693
	.sendpage =	unix_stream_sendpage,
694
	.splice_read =	unix_stream_splice_read,
695
	.set_peek_off =	unix_set_peek_off,
L
Linus Torvalds 已提交
696 697
};

698
static const struct proto_ops unix_dgram_ops = {
L
Linus Torvalds 已提交
699 700 701 702 703 704 705 706
	.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,
707
	.poll =		unix_dgram_poll,
L
Linus Torvalds 已提交
708 709 710 711 712 713 714 715 716
	.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,
717
	.set_peek_off =	unix_set_peek_off,
L
Linus Torvalds 已提交
718 719
};

720
static const struct proto_ops unix_seqpacket_ops = {
L
Linus Torvalds 已提交
721 722 723 724 725 726 727 728
	.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,
729
	.poll =		unix_dgram_poll,
L
Linus Torvalds 已提交
730 731 732 733 734 735
	.ioctl =	unix_ioctl,
	.listen =	unix_listen,
	.shutdown =	unix_shutdown,
	.setsockopt =	sock_no_setsockopt,
	.getsockopt =	sock_no_getsockopt,
	.sendmsg =	unix_seqpacket_sendmsg,
736
	.recvmsg =	unix_seqpacket_recvmsg,
L
Linus Torvalds 已提交
737 738
	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
739
	.set_peek_off =	unix_set_peek_off,
L
Linus Torvalds 已提交
740 741 742
};

static struct proto unix_proto = {
743 744 745
	.name			= "UNIX",
	.owner			= THIS_MODULE,
	.obj_size		= sizeof(struct unix_sock),
L
Linus Torvalds 已提交
746 747
};

748 749 750 751 752 753 754 755
/*
 * 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;

756
static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
L
Linus Torvalds 已提交
757 758 759 760
{
	struct sock *sk = NULL;
	struct unix_sock *u;

E
Eric Dumazet 已提交
761 762
	atomic_long_inc(&unix_nr_socks);
	if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
L
Linus Torvalds 已提交
763 764
		goto out;

765
	sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
L
Linus Torvalds 已提交
766 767 768
	if (!sk)
		goto out;

E
Eric Dumazet 已提交
769
	sock_init_data(sock, sk);
770 771
	lockdep_set_class(&sk->sk_receive_queue.lock,
				&af_unix_sk_receive_queue_lock_key);
L
Linus Torvalds 已提交
772

773
	sk->sk_allocation	= GFP_KERNEL_ACCOUNT;
L
Linus Torvalds 已提交
774
	sk->sk_write_space	= unix_write_space;
775
	sk->sk_max_ack_backlog	= net->unx.sysctl_max_dgram_qlen;
L
Linus Torvalds 已提交
776 777
	sk->sk_destruct		= unix_sock_destructor;
	u	  = unix_sk(sk);
A
Al Viro 已提交
778 779
	u->path.dentry = NULL;
	u->path.mnt = NULL;
780
	spin_lock_init(&u->lock);
A
Al Viro 已提交
781
	atomic_long_set(&u->inflight, 0);
782
	INIT_LIST_HEAD(&u->link);
783 784
	mutex_init(&u->iolock); /* single task reading lock */
	mutex_init(&u->bindlock); /* single task binding lock */
L
Linus Torvalds 已提交
785
	init_waitqueue_head(&u->peer_wait);
786
	init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
E
Eric Dumazet 已提交
787
	unix_insert_socket(unix_sockets_unbound(sk), sk);
L
Linus Torvalds 已提交
788
out:
789
	if (sk == NULL)
E
Eric Dumazet 已提交
790
		atomic_long_dec(&unix_nr_socks);
791 792
	else {
		local_bh_disable();
793
		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
794 795
		local_bh_enable();
	}
L
Linus Torvalds 已提交
796 797 798
	return sk;
}

799 800
static int unix_create(struct net *net, struct socket *sock, int protocol,
		       int kern)
L
Linus Torvalds 已提交
801 802 803 804 805 806 807 808 809 810 811 812 813 814 815
{
	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:
816
		sock->type = SOCK_DGRAM;
L
Linus Torvalds 已提交
817 818 819 820 821 822 823 824 825 826
	case SOCK_DGRAM:
		sock->ops = &unix_dgram_ops;
		break;
	case SOCK_SEQPACKET:
		sock->ops = &unix_seqpacket_ops;
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}

827
	return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
L
Linus Torvalds 已提交
828 829 830 831 832 833 834 835 836
}

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

	if (!sk)
		return 0;

837
	unix_release_sock(sk, 0);
L
Linus Torvalds 已提交
838 839
	sock->sk = NULL;

840
	return 0;
L
Linus Torvalds 已提交
841 842 843 844 845
}

static int unix_autobind(struct socket *sock)
{
	struct sock *sk = sock->sk;
846
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
847 848
	struct unix_sock *u = unix_sk(sk);
	static u32 ordernum = 1;
E
Eric Dumazet 已提交
849
	struct unix_address *addr;
L
Linus Torvalds 已提交
850
	int err;
851
	unsigned int retries = 0;
L
Linus Torvalds 已提交
852

853
	err = mutex_lock_interruptible(&u->bindlock);
854 855
	if (err)
		return err;
L
Linus Torvalds 已提交
856 857 858 859 860 861

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

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

	addr->name->sun_family = AF_UNIX;
867
	refcount_set(&addr->refcnt, 1);
L
Linus Torvalds 已提交
868 869 870

retry:
	addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
871
	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
L
Linus Torvalds 已提交
872

873
	spin_lock(&unix_table_lock);
L
Linus Torvalds 已提交
874 875
	ordernum = (ordernum+1)&0xFFFFF;

876
	if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
L
Linus Torvalds 已提交
877
				      addr->hash)) {
878
		spin_unlock(&unix_table_lock);
879 880 881 882 883 884 885 886 887 888 889
		/*
		 * __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
890 891 892 893 894 895 896
		goto retry;
	}
	addr->hash ^= sk->sk_type;

	__unix_remove_socket(sk);
	u->addr = addr;
	__unix_insert_socket(&unix_socket_table[addr->hash], sk);
897
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
898 899
	err = 0;

900
out:	mutex_unlock(&u->bindlock);
L
Linus Torvalds 已提交
901 902 903
	return err;
}

904 905
static struct sock *unix_find_other(struct net *net,
				    struct sockaddr_un *sunname, int len,
906
				    int type, unsigned int hash, int *error)
L
Linus Torvalds 已提交
907 908
{
	struct sock *u;
909
	struct path path;
L
Linus Torvalds 已提交
910
	int err = 0;
911

L
Linus Torvalds 已提交
912
	if (sunname->sun_path[0]) {
913 914
		struct inode *inode;
		err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
L
Linus Torvalds 已提交
915 916
		if (err)
			goto fail;
917
		inode = d_backing_inode(path.dentry);
918
		err = inode_permission(inode, MAY_WRITE);
L
Linus Torvalds 已提交
919 920 921 922
		if (err)
			goto put_fail;

		err = -ECONNREFUSED;
923
		if (!S_ISSOCK(inode->i_mode))
L
Linus Torvalds 已提交
924
			goto put_fail;
925
		u = unix_find_socket_byinode(inode);
L
Linus Torvalds 已提交
926 927 928 929
		if (!u)
			goto put_fail;

		if (u->sk_type == type)
A
Al Viro 已提交
930
			touch_atime(&path);
L
Linus Torvalds 已提交
931

932
		path_put(&path);
L
Linus Torvalds 已提交
933

934
		err = -EPROTOTYPE;
L
Linus Torvalds 已提交
935 936 937 938 939 940
		if (u->sk_type != type) {
			sock_put(u);
			goto fail;
		}
	} else {
		err = -ECONNREFUSED;
941
		u = unix_find_socket_byname(net, sunname, len, type, hash);
L
Linus Torvalds 已提交
942 943
		if (u) {
			struct dentry *dentry;
A
Al Viro 已提交
944
			dentry = unix_sk(u)->path.dentry;
L
Linus Torvalds 已提交
945
			if (dentry)
A
Al Viro 已提交
946
				touch_atime(&unix_sk(u)->path);
L
Linus Torvalds 已提交
947 948 949 950 951 952
		} else
			goto fail;
	}
	return u;

put_fail:
953
	path_put(&path);
L
Linus Torvalds 已提交
954
fail:
955
	*error = err;
L
Linus Torvalds 已提交
956 957 958
	return NULL;
}

959
static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
A
Al Viro 已提交
960
{
961 962 963 964 965 966 967 968 969 970 971
	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
972

973 974 975 976
	/*
	 * All right, let's create it.
	 */
	err = security_path_mknod(&path, dentry, mode, 0);
A
Al Viro 已提交
977
	if (!err) {
978
		err = vfs_mknod(d_inode(path.dentry), dentry, mode, 0);
A
Al Viro 已提交
979
		if (!err) {
980
			res->mnt = mntget(path.mnt);
A
Al Viro 已提交
981 982 983
			res->dentry = dget(dentry);
		}
	}
984
	done_path_create(&path, dentry);
A
Al Viro 已提交
985 986
	return err;
}
L
Linus Torvalds 已提交
987 988 989 990

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

	err = -EINVAL;
1002 1003
	if (addr_len < offsetofend(struct sockaddr_un, sun_family) ||
	    sunaddr->sun_family != AF_UNIX)
L
Linus Torvalds 已提交
1004 1005
		goto out;

1006
	if (addr_len == sizeof(short)) {
L
Linus Torvalds 已提交
1007 1008 1009 1010 1011 1012 1013 1014 1015
		err = unix_autobind(sock);
		goto out;
	}

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

1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026
	if (sun_path[0]) {
		umode_t mode = S_IFSOCK |
		       (SOCK_INODE(sock)->i_mode & ~current_umask());
		err = unix_mknod(sun_path, mode, &path);
		if (err) {
			if (err == -EEXIST)
				err = -EADDRINUSE;
			goto out;
		}
	}

1027
	err = mutex_lock_interruptible(&u->bindlock);
1028
	if (err)
1029
		goto out_put;
L
Linus Torvalds 已提交
1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042

	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;
1043
	refcount_set(&addr->refcnt, 1);
L
Linus Torvalds 已提交
1044

1045
	if (sun_path[0]) {
L
Linus Torvalds 已提交
1046
		addr->hash = UNIX_HASH_SIZE;
1047
		hash = d_backing_inode(path.dentry)->i_ino & (UNIX_HASH_SIZE - 1);
A
Al Viro 已提交
1048
		spin_lock(&unix_table_lock);
1049
		u->path = path;
A
Al Viro 已提交
1050 1051 1052
		list = &unix_socket_table[hash];
	} else {
		spin_lock(&unix_table_lock);
L
Linus Torvalds 已提交
1053
		err = -EADDRINUSE;
1054
		if (__unix_find_socket_byname(net, sunaddr, addr_len,
L
Linus Torvalds 已提交
1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068
					      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:
1069
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
1070
out_up:
1071
	mutex_unlock(&u->bindlock);
1072 1073 1074
out_put:
	if (err)
		path_put(&path);
L
Linus Torvalds 已提交
1075 1076 1077 1078
out:
	return err;
}

1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103
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
1104 1105 1106 1107
static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
			      int alen, int flags)
{
	struct sock *sk = sock->sk;
1108
	struct net *net = sock_net(sk);
1109
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
L
Linus Torvalds 已提交
1110
	struct sock *other;
1111
	unsigned int hash;
L
Linus Torvalds 已提交
1112 1113
	int err;

1114 1115 1116 1117
	err = -EINVAL;
	if (alen < offsetofend(struct sockaddr, sa_family))
		goto out;

L
Linus Torvalds 已提交
1118 1119 1120 1121 1122 1123 1124 1125 1126 1127
	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;

1128
restart:
1129
		other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
L
Linus Torvalds 已提交
1130 1131 1132
		if (!other)
			goto out;

1133 1134 1135 1136 1137 1138 1139 1140
		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
1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154

		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;
1155
		unix_state_double_lock(sk, other);
L
Linus Torvalds 已提交
1156 1157 1158 1159 1160 1161 1162
	}

	/*
	 * If it was connected, reconnect.
	 */
	if (unix_peer(sk)) {
		struct sock *old_peer = unix_peer(sk);
1163
		unix_peer(sk) = other;
1164 1165
		unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);

1166
		unix_state_double_unlock(sk, other);
L
Linus Torvalds 已提交
1167 1168 1169 1170 1171

		if (other != old_peer)
			unix_dgram_disconnected(sk, old_peer);
		sock_put(old_peer);
	} else {
1172
		unix_peer(sk) = other;
1173
		unix_state_double_unlock(sk, other);
L
Linus Torvalds 已提交
1174
	}
1175
	return 0;
L
Linus Torvalds 已提交
1176 1177

out_unlock:
1178
	unix_state_double_unlock(sk, other);
L
Linus Torvalds 已提交
1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193
	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) &&
1194
		unix_recvq_full(other);
L
Linus Torvalds 已提交
1195

1196
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207

	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)
{
1208
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
L
Linus Torvalds 已提交
1209
	struct sock *sk = sock->sk;
1210
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1211 1212 1213 1214
	struct unix_sock *u = unix_sk(sk), *newu, *otheru;
	struct sock *newsk = NULL;
	struct sock *other = NULL;
	struct sk_buff *skb = NULL;
1215
	unsigned int hash;
L
Linus Torvalds 已提交
1216 1217 1218 1219 1220 1221 1222 1223 1224
	int st;
	int err;
	long timeo;

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

1225 1226
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
	    (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238
		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 */
1239
	newsk = unix_create1(sock_net(sk), NULL, 0);
L
Linus Torvalds 已提交
1240 1241 1242 1243 1244 1245 1246 1247 1248 1249
	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. */
1250
	other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
L
Linus Torvalds 已提交
1251 1252 1253 1254
	if (!other)
		goto out;

	/* Latch state of peer */
1255
	unix_state_lock(other);
L
Linus Torvalds 已提交
1256 1257 1258

	/* Apparently VFS overslept socket death. Retry. */
	if (sock_flag(other, SOCK_DEAD)) {
1259
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1260 1261 1262 1263 1264 1265 1266
		sock_put(other);
		goto restart;
	}

	err = -ECONNREFUSED;
	if (other->sk_state != TCP_LISTEN)
		goto out_unlock;
1267 1268
	if (other->sk_shutdown & RCV_SHUTDOWN)
		goto out_unlock;
L
Linus Torvalds 已提交
1269

1270
	if (unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281
		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;
1282
	}
L
Linus Torvalds 已提交
1283 1284 1285

	/* Latch our state.

D
Daniel Baluta 已提交
1286
	   It is tricky place. We need to grab our state lock and cannot
L
Linus Torvalds 已提交
1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309
	   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;
	}

1310
	unix_state_lock_nested(sk);
L
Linus Torvalds 已提交
1311 1312

	if (sk->sk_state != st) {
1313 1314
		unix_state_unlock(sk);
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1315 1316 1317 1318
		sock_put(other);
		goto restart;
	}

1319
	err = security_unix_stream_connect(sk, other, newsk);
L
Linus Torvalds 已提交
1320
	if (err) {
1321
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1322 1323 1324 1325 1326 1327 1328 1329 1330
		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;
1331
	init_peercred(newsk);
L
Linus Torvalds 已提交
1332
	newu = unix_sk(newsk);
1333
	RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
L
Linus Torvalds 已提交
1334 1335 1336 1337
	otheru = unix_sk(other);

	/* copy address information from listening to new sock*/
	if (otheru->addr) {
1338
		refcount_inc(&otheru->addr->refcnt);
L
Linus Torvalds 已提交
1339 1340
		newu->addr = otheru->addr;
	}
A
Al Viro 已提交
1341 1342 1343
	if (otheru->path.dentry) {
		path_get(&otheru->path);
		newu->path = otheru->path;
L
Linus Torvalds 已提交
1344 1345 1346
	}

	/* Set credentials */
1347
	copy_peercred(sk, other);
L
Linus Torvalds 已提交
1348 1349 1350

	sock->state	= SS_CONNECTED;
	sk->sk_state	= TCP_ESTABLISHED;
1351 1352
	sock_hold(newsk);

1353
	smp_mb__after_atomic();	/* sock_hold() does an atomic_inc() */
1354
	unix_peer(sk)	= newsk;
L
Linus Torvalds 已提交
1355

1356
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1357 1358 1359 1360 1361

	/* 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);
1362
	unix_state_unlock(other);
1363
	other->sk_data_ready(other);
L
Linus Torvalds 已提交
1364 1365 1366 1367 1368
	sock_put(other);
	return 0;

out_unlock:
	if (other)
1369
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1370 1371

out:
1372
	kfree_skb(skb);
L
Linus Torvalds 已提交
1373 1374 1375 1376 1377 1378 1379 1380 1381
	if (newsk)
		unix_release_sock(newsk, 0);
	if (other)
		sock_put(other);
	return err;
}

static int unix_socketpair(struct socket *socka, struct socket *sockb)
{
1382
	struct sock *ska = socka->sk, *skb = sockb->sk;
L
Linus Torvalds 已提交
1383 1384 1385 1386

	/* Join our sockets back to back */
	sock_hold(ska);
	sock_hold(skb);
1387 1388
	unix_peer(ska) = skb;
	unix_peer(skb) = ska;
1389 1390
	init_peercred(ska);
	init_peercred(skb);
L
Linus Torvalds 已提交
1391 1392 1393 1394 1395 1396 1397 1398 1399 1400

	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;
}

1401 1402 1403 1404 1405 1406 1407 1408 1409
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);
}

1410 1411
static int unix_accept(struct socket *sock, struct socket *newsock, int flags,
		       bool kern)
L
Linus Torvalds 已提交
1412 1413 1414 1415 1416 1417 1418
{
	struct sock *sk = sock->sk;
	struct sock *tsk;
	struct sk_buff *skb;
	int err;

	err = -EOPNOTSUPP;
E
Eric Dumazet 已提交
1419
	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
L
Linus Torvalds 已提交
1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442
		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 */
1443
	unix_state_lock(tsk);
L
Linus Torvalds 已提交
1444
	newsock->state = SS_CONNECTED;
1445
	unix_sock_inherit_flags(sock, newsock);
L
Linus Torvalds 已提交
1446
	sock_graft(tsk, newsock);
1447
	unix_state_unlock(tsk);
L
Linus Torvalds 已提交
1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458
	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;
1459
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
L
Linus Torvalds 已提交
1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473
	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);
1474
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1475 1476 1477 1478 1479 1480 1481 1482 1483 1484
	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);
	}
1485
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497
	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
1498
	for (i = scm->fp->count-1; i >= 0; i--)
1499
		unix_notinflight(scm->fp->user, scm->fp->fp[i]);
L
Linus Torvalds 已提交
1500 1501
}

1502
static void unix_destruct_scm(struct sk_buff *skb)
L
Linus Torvalds 已提交
1503 1504 1505
{
	struct scm_cookie scm;
	memset(&scm, 0, sizeof(scm));
1506 1507 1508
	scm.pid  = UNIXCB(skb).pid;
	if (UNIXCB(skb).fp)
		unix_detach_fds(&scm, skb);
L
Linus Torvalds 已提交
1509 1510 1511 1512 1513 1514 1515

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

1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530
/*
 * 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;
}

1531
static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
L
Linus Torvalds 已提交
1532 1533
{
	int i;
E
Eric Dumazet 已提交
1534

1535 1536 1537
	if (too_many_unix_fds(current))
		return -ETOOMANYREFS;

1538 1539 1540 1541 1542 1543 1544 1545 1546
	/*
	 * 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;

1547
	for (i = scm->fp->count - 1; i >= 0; i--)
1548
		unix_inflight(scm->fp->user, scm->fp->fp[i]);
1549
	return 0;
L
Linus Torvalds 已提交
1550 1551
}

1552
static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1553 1554
{
	int err = 0;
1555

1556
	UNIXCB(skb).pid  = get_pid(scm->pid);
1557 1558
	UNIXCB(skb).uid = scm->creds.uid;
	UNIXCB(skb).gid = scm->creds.gid;
1559
	UNIXCB(skb).fp = NULL;
1560
	unix_get_secdata(scm, skb);
1561 1562 1563 1564 1565 1566 1567
	if (scm->fp && send_fds)
		err = unix_attach_fds(scm, skb);

	skb->destructor = unix_destruct_scm;
	return err;
}

1568 1569 1570 1571 1572 1573 1574 1575
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);
}

1576 1577 1578 1579 1580 1581 1582 1583
/*
 * 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)
{
1584
	if (UNIXCB(skb).pid)
1585
		return;
1586
	if (unix_passcred_enabled(sock, other)) {
1587
		UNIXCB(skb).pid  = get_pid(task_tgid(current));
1588
		current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1589 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
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
1621 1622 1623 1624
/*
 *	Send AF_UNIX data.
 */

1625 1626
static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
			      size_t len)
L
Linus Torvalds 已提交
1627 1628
{
	struct sock *sk = sock->sk;
1629
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1630
	struct unix_sock *u = unix_sk(sk);
1631
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
L
Linus Torvalds 已提交
1632 1633 1634
	struct sock *other = NULL;
	int namelen = 0; /* fake GCC */
	int err;
1635
	unsigned int hash;
1636
	struct sk_buff *skb;
L
Linus Torvalds 已提交
1637
	long timeo;
C
Christoph Hellwig 已提交
1638
	struct scm_cookie scm;
1639
	int data_len = 0;
1640
	int sk_locked;
L
Linus Torvalds 已提交
1641

1642
	wait_for_unix_gc();
C
Christoph Hellwig 已提交
1643
	err = scm_send(sock, msg, &scm, false);
L
Linus Torvalds 已提交
1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663
	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;
	}

1664 1665
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
	    && (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1666 1667 1668 1669 1670 1671
		goto out;

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

1672
	if (len > SKB_MAX_ALLOC) {
1673 1674 1675
		data_len = min_t(size_t,
				 len - SKB_MAX_ALLOC,
				 MAX_SKB_FRAGS * PAGE_SIZE);
1676 1677 1678 1679
		data_len = PAGE_ALIGN(data_len);

		BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
	}
1680 1681

	skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1682 1683
				   msg->msg_flags & MSG_DONTWAIT, &err,
				   PAGE_ALLOC_COSTLY_ORDER);
1684
	if (skb == NULL)
L
Linus Torvalds 已提交
1685 1686
		goto out;

C
Christoph Hellwig 已提交
1687
	err = unix_scm_to_skb(&scm, skb, true);
E
Eric Dumazet 已提交
1688
	if (err < 0)
1689
		goto out_free;
C
Catherine Zhang 已提交
1690

1691 1692 1693
	skb_put(skb, len - data_len);
	skb->data_len = data_len;
	skb->len = len;
A
Al Viro 已提交
1694
	err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
L
Linus Torvalds 已提交
1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705
	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;

1706
		other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
L
Linus Torvalds 已提交
1707
					hash, &err);
1708
		if (other == NULL)
L
Linus Torvalds 已提交
1709 1710 1711
			goto out_free;
	}

A
Alban Crequy 已提交
1712 1713 1714 1715 1716 1717
	if (sk_filter(other, skb) < 0) {
		/* Toss the packet but do not return any error to the sender */
		err = len;
		goto out_free;
	}

1718
	sk_locked = 0;
1719
	unix_state_lock(other);
1720
restart_locked:
L
Linus Torvalds 已提交
1721 1722 1723 1724
	err = -EPERM;
	if (!unix_may_send(sk, other))
		goto out_unlock;

1725
	if (unlikely(sock_flag(other, SOCK_DEAD))) {
L
Linus Torvalds 已提交
1726 1727 1728 1729
		/*
		 *	Check with 1003.1g - what should
		 *	datagram error
		 */
1730
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1731 1732
		sock_put(other);

1733 1734 1735
		if (!sk_locked)
			unix_state_lock(sk);

L
Linus Torvalds 已提交
1736 1737
		err = 0;
		if (unix_peer(sk) == other) {
1738
			unix_peer(sk) = NULL;
1739 1740
			unix_dgram_peer_wake_disconnect_wakeup(sk, other);

1741
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1742 1743 1744 1745 1746

			unix_dgram_disconnected(sk, other);
			sock_put(other);
			err = -ECONNREFUSED;
		} else {
1747
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765
		}

		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;
	}

1766 1767 1768 1769 1770 1771
	/* 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))) {
1772 1773 1774 1775 1776 1777 1778 1779
		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
1780 1781
		}

1782 1783 1784 1785
		if (!sk_locked) {
			unix_state_unlock(other);
			unix_state_double_lock(sk, other);
		}
L
Linus Torvalds 已提交
1786

1787 1788 1789 1790 1791 1792
		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
1793

1794 1795 1796 1797
		if (!sk_locked) {
			sk_locked = 1;
			goto restart_locked;
		}
L
Linus Torvalds 已提交
1798 1799
	}

1800 1801 1802
	if (unlikely(sk_locked))
		unix_state_unlock(sk);

1803 1804
	if (sock_flag(other, SOCK_RCVTSTAMP))
		__net_timestamp(skb);
1805
	maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1806
	skb_queue_tail(&other->sk_receive_queue, skb);
1807
	unix_state_unlock(other);
1808
	other->sk_data_ready(other);
L
Linus Torvalds 已提交
1809
	sock_put(other);
C
Christoph Hellwig 已提交
1810
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1811 1812 1813
	return len;

out_unlock:
1814 1815
	if (sk_locked)
		unix_state_unlock(sk);
1816
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1817 1818 1819 1820 1821
out_free:
	kfree_skb(skb);
out:
	if (other)
		sock_put(other);
C
Christoph Hellwig 已提交
1822
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1823 1824 1825
	return err;
}

1826 1827 1828 1829
/* 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))
1830

1831 1832
static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
			       size_t len)
L
Linus Torvalds 已提交
1833 1834 1835
{
	struct sock *sk = sock->sk;
	struct sock *other = NULL;
E
Eric Dumazet 已提交
1836
	int err, size;
1837
	struct sk_buff *skb;
1838
	int sent = 0;
C
Christoph Hellwig 已提交
1839
	struct scm_cookie scm;
1840
	bool fds_sent = false;
1841
	int data_len;
L
Linus Torvalds 已提交
1842

1843
	wait_for_unix_gc();
C
Christoph Hellwig 已提交
1844
	err = scm_send(sock, msg, &scm, false);
L
Linus Torvalds 已提交
1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856
	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;
1857
		other = unix_peer(sk);
L
Linus Torvalds 已提交
1858 1859 1860 1861 1862 1863 1864
		if (!other)
			goto out_err;
	}

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

E
Eric Dumazet 已提交
1865
	while (sent < len) {
1866
		size = len - sent;
L
Linus Torvalds 已提交
1867 1868

		/* Keep two messages in the pipe so it schedules better */
1869
		size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
L
Linus Torvalds 已提交
1870

1871 1872
		/* allow fallback to order-0 allocations */
		size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1873

1874
		data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
L
Linus Torvalds 已提交
1875

1876 1877
		data_len = min_t(size_t, size, PAGE_ALIGN(data_len));

1878
		skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1879 1880
					   msg->msg_flags & MSG_DONTWAIT, &err,
					   get_order(UNIX_SKB_FRAGS_SZ));
1881
		if (!skb)
L
Linus Torvalds 已提交
1882 1883
			goto out_err;

1884
		/* Only send the fds in the first buffer */
C
Christoph Hellwig 已提交
1885
		err = unix_scm_to_skb(&scm, skb, !fds_sent);
E
Eric Dumazet 已提交
1886
		if (err < 0) {
1887
			kfree_skb(skb);
1888
			goto out_err;
1889
		}
1890
		fds_sent = true;
L
Linus Torvalds 已提交
1891

1892 1893 1894
		skb_put(skb, size - data_len);
		skb->data_len = data_len;
		skb->len = size;
A
Al Viro 已提交
1895
		err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
E
Eric Dumazet 已提交
1896
		if (err) {
L
Linus Torvalds 已提交
1897
			kfree_skb(skb);
1898
			goto out_err;
L
Linus Torvalds 已提交
1899 1900
		}

1901
		unix_state_lock(other);
L
Linus Torvalds 已提交
1902 1903 1904 1905 1906

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

1907
		maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1908
		skb_queue_tail(&other->sk_receive_queue, skb);
1909
		unix_state_unlock(other);
1910
		other->sk_data_ready(other);
1911
		sent += size;
L
Linus Torvalds 已提交
1912 1913
	}

C
Christoph Hellwig 已提交
1914
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1915 1916 1917 1918

	return sent;

pipe_err_free:
1919
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1920 1921
	kfree_skb(skb);
pipe_err:
E
Eric Dumazet 已提交
1922 1923
	if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
L
Linus Torvalds 已提交
1924 1925
	err = -EPIPE;
out_err:
C
Christoph Hellwig 已提交
1926
	scm_destroy(&scm);
L
Linus Torvalds 已提交
1927 1928 1929
	return sent ? : err;
}

1930 1931 1932
static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
				    int offset, size_t size, int flags)
{
1933 1934 1935 1936
	int err;
	bool send_sigpipe = false;
	bool init_scm = true;
	struct scm_cookie scm;
1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949
	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);
1950
		mutex_unlock(&unix_sk(other)->iolock);
1951 1952 1953
		newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
					      &err, 0);
		if (!newskb)
1954
			goto err;
1955 1956
	}

1957
	/* we must acquire iolock as we modify already present
1958 1959
	 * skbs in the sk_receive_queue and mess with skb->len
	 */
1960
	err = mutex_lock_interruptible(&unix_sk(other)->iolock);
1961 1962 1963 1964 1965 1966 1967
	if (err) {
		err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
		goto err;
	}

	if (sk->sk_shutdown & SEND_SHUTDOWN) {
		err = -EPIPE;
1968
		send_sigpipe = true;
1969 1970 1971 1972 1973 1974 1975 1976
		goto err_unlock;
	}

	unix_state_lock(other);

	if (sock_flag(other, SOCK_DEAD) ||
	    other->sk_shutdown & RCV_SHUTDOWN) {
		err = -EPIPE;
1977
		send_sigpipe = true;
1978 1979 1980
		goto err_state_unlock;
	}

1981 1982 1983 1984 1985 1986 1987
	if (init_scm) {
		err = maybe_init_creds(&scm, socket, other);
		if (err)
			goto err_state_unlock;
		init_scm = false;
	}

1988 1989 1990
	skb = skb_peek_tail(&other->sk_receive_queue);
	if (tail && tail == skb) {
		skb = newskb;
1991 1992
	} else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
		if (newskb) {
1993
			skb = newskb;
1994 1995
		} else {
			tail = skb;
1996
			goto alloc_skb;
1997
		}
1998 1999 2000 2001 2002 2003
	} 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);
2004
		newskb = NULL;
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
	}

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

	skb->len += size;
	skb->data_len += size;
	skb->truesize += size;
2015
	refcount_add(size, &sk->sk_wmem_alloc);
2016

2017
	if (newskb) {
2018 2019 2020
		err = unix_scm_to_skb(&scm, skb, false);
		if (err)
			goto err_state_unlock;
2021
		spin_lock(&other->sk_receive_queue.lock);
2022
		__skb_queue_tail(&other->sk_receive_queue, newskb);
2023 2024
		spin_unlock(&other->sk_receive_queue.lock);
	}
2025 2026

	unix_state_unlock(other);
2027
	mutex_unlock(&unix_sk(other)->iolock);
2028 2029

	other->sk_data_ready(other);
2030
	scm_destroy(&scm);
2031 2032 2033 2034 2035
	return size;

err_state_unlock:
	unix_state_unlock(other);
err_unlock:
2036
	mutex_unlock(&unix_sk(other)->iolock);
2037 2038 2039 2040
err:
	kfree_skb(newskb);
	if (send_sigpipe && !(flags & MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
2041 2042
	if (!init_scm)
		scm_destroy(&scm);
2043 2044 2045
	return err;
}

2046 2047
static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
				  size_t len)
L
Linus Torvalds 已提交
2048 2049 2050
{
	int err;
	struct sock *sk = sock->sk;
2051

L
Linus Torvalds 已提交
2052 2053 2054 2055 2056 2057 2058 2059 2060 2061
	err = sock_error(sk);
	if (err)
		return err;

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

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

2062
	return unix_dgram_sendmsg(sock, msg, len);
L
Linus Torvalds 已提交
2063
}
2064

2065 2066
static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg,
				  size_t size, int flags)
2067 2068 2069 2070 2071 2072
{
	struct sock *sk = sock->sk;

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

2073
	return unix_dgram_recvmsg(sock, msg, size, flags);
2074 2075
}

L
Linus Torvalds 已提交
2076 2077 2078 2079 2080 2081 2082 2083 2084 2085
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);
	}
}

2086 2087
static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
			      size_t size, int flags)
L
Linus Torvalds 已提交
2088
{
C
Christoph Hellwig 已提交
2089
	struct scm_cookie scm;
L
Linus Torvalds 已提交
2090 2091
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
2092 2093
	struct sk_buff *skb, *last;
	long timeo;
L
Linus Torvalds 已提交
2094
	int err;
2095
	int peeked, skip;
L
Linus Torvalds 已提交
2096 2097 2098 2099 2100

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

2101
	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
L
Linus Torvalds 已提交
2102

2103
	do {
2104
		mutex_lock(&u->iolock);
2105

2106
		skip = sk_peek_offset(sk, flags);
2107 2108
		skb = __skb_try_recv_datagram(sk, flags, NULL, &peeked, &skip,
					      &err, &last);
2109 2110 2111
		if (skb)
			break;

2112
		mutex_unlock(&u->iolock);
2113 2114 2115 2116 2117 2118

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

2119
	if (!skb) { /* implies iolock unlocked */
2120 2121 2122 2123 2124 2125
		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);
2126
		goto out;
2127
	}
L
Linus Torvalds 已提交
2128

2129 2130 2131 2132
	if (wq_has_sleeper(&u->peer_wait))
		wake_up_interruptible_sync_poll(&u->peer_wait,
						POLLOUT | POLLWRNORM |
						POLLWRBAND);
L
Linus Torvalds 已提交
2133 2134 2135 2136

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

2137 2138 2139
	if (size > skb->len - skip)
		size = skb->len - skip;
	else if (size < skb->len - skip)
L
Linus Torvalds 已提交
2140 2141
		msg->msg_flags |= MSG_TRUNC;

2142
	err = skb_copy_datagram_msg(skb, skip, msg, size);
L
Linus Torvalds 已提交
2143 2144 2145
	if (err)
		goto out_free;

2146 2147 2148
	if (sock_flag(sk, SOCK_RCVTSTAMP))
		__sock_recv_timestamp(msg, sk, skb);

C
Christoph Hellwig 已提交
2149 2150 2151 2152
	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
2153

E
Eric Dumazet 已提交
2154
	if (!(flags & MSG_PEEK)) {
L
Linus Torvalds 已提交
2155
		if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
2156
			unix_detach_fds(&scm, skb);
2157 2158

		sk_peek_offset_bwd(sk, skb->len);
E
Eric Dumazet 已提交
2159
	} else {
L
Linus Torvalds 已提交
2160 2161 2162 2163 2164 2165
		/* 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)
2166 2167 2168 2169 2170

		   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
2171
		*/
2172 2173 2174

		sk_peek_offset_fwd(sk, size);

L
Linus Torvalds 已提交
2175
		if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
2176
			scm.fp = scm_fp_dup(UNIXCB(skb).fp);
L
Linus Torvalds 已提交
2177
	}
2178
	err = (flags & MSG_TRUNC) ? skb->len - skip : size;
L
Linus Torvalds 已提交
2179

C
Christoph Hellwig 已提交
2180
	scm_recv(sock, msg, &scm, flags);
L
Linus Torvalds 已提交
2181 2182

out_free:
E
Eric Dumazet 已提交
2183
	skb_free_datagram(sk, skb);
2184
	mutex_unlock(&u->iolock);
L
Linus Torvalds 已提交
2185 2186 2187 2188 2189
out:
	return err;
}

/*
2190
 *	Sleep until more data has arrived. But check for races..
L
Linus Torvalds 已提交
2191
 */
2192
static long unix_stream_data_wait(struct sock *sk, long timeo,
2193 2194
				  struct sk_buff *last, unsigned int last_len,
				  bool freezable)
L
Linus Torvalds 已提交
2195
{
2196
	struct sk_buff *tail;
L
Linus Torvalds 已提交
2197 2198
	DEFINE_WAIT(wait);

2199
	unix_state_lock(sk);
L
Linus Torvalds 已提交
2200 2201

	for (;;) {
E
Eric Dumazet 已提交
2202
		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
L
Linus Torvalds 已提交
2203

2204 2205 2206
		tail = skb_peek_tail(&sk->sk_receive_queue);
		if (tail != last ||
		    (tail && tail->len != last_len) ||
L
Linus Torvalds 已提交
2207 2208 2209 2210 2211 2212
		    sk->sk_err ||
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
		    signal_pending(current) ||
		    !timeo)
			break;

2213
		sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2214
		unix_state_unlock(sk);
2215 2216 2217 2218
		if (freezable)
			timeo = freezable_schedule_timeout(timeo);
		else
			timeo = schedule_timeout(timeo);
2219
		unix_state_lock(sk);
2220 2221 2222 2223

		if (sock_flag(sk, SOCK_DEAD))
			break;

2224
		sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
L
Linus Torvalds 已提交
2225 2226
	}

E
Eric Dumazet 已提交
2227
	finish_wait(sk_sleep(sk), &wait);
2228
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
2229 2230 2231
	return timeo;
}

2232 2233 2234 2235 2236
static unsigned int unix_skb_len(const struct sk_buff *skb)
{
	return skb->len - UNIXCB(skb).consumed;
}

2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247
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;
};

2248 2249
static int unix_stream_read_generic(struct unix_stream_read_state *state,
				    bool freezable)
L
Linus Torvalds 已提交
2250
{
C
Christoph Hellwig 已提交
2251
	struct scm_cookie scm;
2252
	struct socket *sock = state->socket;
L
Linus Torvalds 已提交
2253 2254 2255
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
	int copied = 0;
2256
	int flags = state->flags;
2257
	int noblock = flags & MSG_DONTWAIT;
2258
	bool check_creds = false;
L
Linus Torvalds 已提交
2259 2260 2261
	int target;
	int err = 0;
	long timeo;
2262
	int skip;
2263 2264
	size_t size = state->size;
	unsigned int last_len;
L
Linus Torvalds 已提交
2265

2266 2267
	if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
		err = -EINVAL;
L
Linus Torvalds 已提交
2268
		goto out;
2269
	}
L
Linus Torvalds 已提交
2270

2271 2272
	if (unlikely(flags & MSG_OOB)) {
		err = -EOPNOTSUPP;
L
Linus Torvalds 已提交
2273
		goto out;
2274
	}
L
Linus Torvalds 已提交
2275

2276
	target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
2277
	timeo = sock_rcvtimeo(sk, noblock);
L
Linus Torvalds 已提交
2278

2279 2280
	memset(&scm, 0, sizeof(scm));

L
Linus Torvalds 已提交
2281 2282 2283
	/* Lock the socket to prevent queue disordering
	 * while sleeps in memcpy_tomsg
	 */
2284
	mutex_lock(&u->iolock);
L
Linus Torvalds 已提交
2285

2286
	skip = max(sk_peek_offset(sk, flags), 0);
2287

E
Eric Dumazet 已提交
2288
	do {
L
Linus Torvalds 已提交
2289
		int chunk;
2290
		bool drop_skb;
2291
		struct sk_buff *skb, *last;
L
Linus Torvalds 已提交
2292

2293
redo:
2294
		unix_state_lock(sk);
2295 2296 2297 2298
		if (sock_flag(sk, SOCK_DEAD)) {
			err = -ECONNRESET;
			goto unlock;
		}
2299
		last = skb = skb_peek(&sk->sk_receive_queue);
2300
		last_len = last ? last->len : 0;
2301
again:
E
Eric Dumazet 已提交
2302
		if (skb == NULL) {
L
Linus Torvalds 已提交
2303
			if (copied >= target)
2304
				goto unlock;
L
Linus Torvalds 已提交
2305 2306 2307 2308

			/*
			 *	POSIX 1003.1g mandates this order.
			 */
2309

E
Eric Dumazet 已提交
2310 2311
			err = sock_error(sk);
			if (err)
2312
				goto unlock;
L
Linus Torvalds 已提交
2313
			if (sk->sk_shutdown & RCV_SHUTDOWN)
2314 2315 2316
				goto unlock;

			unix_state_unlock(sk);
2317 2318
			if (!timeo) {
				err = -EAGAIN;
L
Linus Torvalds 已提交
2319
				break;
2320 2321
			}

2322
			mutex_unlock(&u->iolock);
L
Linus Torvalds 已提交
2323

2324
			timeo = unix_stream_data_wait(sk, timeo, last,
2325
						      last_len, freezable);
L
Linus Torvalds 已提交
2326

2327
			if (signal_pending(current)) {
L
Linus Torvalds 已提交
2328
				err = sock_intr_errno(timeo);
2329
				scm_destroy(&scm);
L
Linus Torvalds 已提交
2330 2331
				goto out;
			}
2332

2333
			mutex_lock(&u->iolock);
2334
			goto redo;
2335
unlock:
2336 2337
			unix_state_unlock(sk);
			break;
L
Linus Torvalds 已提交
2338
		}
2339

2340 2341
		while (skip >= unix_skb_len(skb)) {
			skip -= unix_skb_len(skb);
2342
			last = skb;
2343
			last_len = skb->len;
2344
			skb = skb_peek_next(skb, &sk->sk_receive_queue);
2345 2346
			if (!skb)
				goto again;
2347 2348
		}

2349
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
2350 2351 2352

		if (check_creds) {
			/* Never glue messages from different writers */
2353
			if (!unix_skb_scm_eq(skb, &scm))
L
Linus Torvalds 已提交
2354
				break;
2355
		} else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
L
Linus Torvalds 已提交
2356
			/* Copy credentials */
C
Christoph Hellwig 已提交
2357
			scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
2358
			unix_set_secdata(&scm, skb);
2359
			check_creds = true;
L
Linus Torvalds 已提交
2360 2361 2362
		}

		/* Copy address just once */
2363 2364 2365 2366
		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
2367 2368 2369
			sunaddr = NULL;
		}

2370
		chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2371
		skb_get(skb);
2372
		chunk = state->recv_actor(skb, skip, chunk, state);
2373 2374 2375
		drop_skb = !unix_skb_len(skb);
		/* skb is only safe to use if !drop_skb */
		consume_skb(skb);
2376
		if (chunk < 0) {
L
Linus Torvalds 已提交
2377 2378 2379 2380 2381 2382 2383
			if (copied == 0)
				copied = -EFAULT;
			break;
		}
		copied += chunk;
		size -= chunk;

2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395
		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
2396
		/* Mark read part of skb as used */
E
Eric Dumazet 已提交
2397
		if (!(flags & MSG_PEEK)) {
2398
			UNIXCB(skb).consumed += chunk;
L
Linus Torvalds 已提交
2399

2400 2401
			sk_peek_offset_bwd(sk, chunk);

L
Linus Torvalds 已提交
2402
			if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
2403
				unix_detach_fds(&scm, skb);
L
Linus Torvalds 已提交
2404

2405
			if (unix_skb_len(skb))
L
Linus Torvalds 已提交
2406 2407
				break;

2408
			skb_unlink(skb, &sk->sk_receive_queue);
2409
			consume_skb(skb);
L
Linus Torvalds 已提交
2410

C
Christoph Hellwig 已提交
2411
			if (scm.fp)
L
Linus Torvalds 已提交
2412
				break;
E
Eric Dumazet 已提交
2413
		} else {
L
Linus Torvalds 已提交
2414 2415 2416
			/* It is questionable, see note in unix_dgram_recvmsg.
			 */
			if (UNIXCB(skb).fp)
C
Christoph Hellwig 已提交
2417
				scm.fp = scm_fp_dup(UNIXCB(skb).fp);
L
Linus Torvalds 已提交
2418

2419
			sk_peek_offset_fwd(sk, chunk);
2420

2421 2422 2423
			if (UNIXCB(skb).fp)
				break;

2424
			skip = 0;
2425 2426 2427 2428 2429 2430 2431
			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
2432 2433 2434 2435
			break;
		}
	} while (size);

2436
	mutex_unlock(&u->iolock);
2437 2438 2439 2440
	if (state->msg)
		scm_recv(sock, state->msg, &scm, flags);
	else
		scm_destroy(&scm);
L
Linus Torvalds 已提交
2441 2442 2443 2444
out:
	return copied ? : err;
}

2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466
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
	};

2467
	return unix_stream_read_generic(&state, true);
2468 2469 2470 2471 2472 2473 2474 2475
}

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
2476
			       state->pipe, chunk, state->splice_flags);
2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497
}

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;

2498
	return unix_stream_read_generic(&state, false);
2499 2500
}

L
Linus Torvalds 已提交
2501 2502 2503 2504 2505
static int unix_shutdown(struct socket *sock, int mode)
{
	struct sock *sk = sock->sk;
	struct sock *other;

2506 2507 2508 2509 2510 2511 2512 2513
	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;
2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539

	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
2540
	}
2541 2542 2543
	if (other)
		sock_put(other);

L
Linus Torvalds 已提交
2544 2545 2546
	return 0;
}

2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558
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)
2559
			amount += unix_skb_len(skb);
2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576
	} 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);

2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613
static int unix_open_file(struct sock *sk)
{
	struct path path;
	struct file *f;
	int fd;

	if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
		return -EPERM;

	unix_state_lock(sk);
	path = unix_sk(sk)->path;
	if (!path.dentry) {
		unix_state_unlock(sk);
		return -ENOENT;
	}

	path_get(&path);
	unix_state_unlock(sk);

	fd = get_unused_fd_flags(O_CLOEXEC);
	if (fd < 0)
		goto out;

	f = dentry_open(&path, O_PATH, current_cred());
	if (IS_ERR(f)) {
		put_unused_fd(fd);
		fd = PTR_ERR(f);
		goto out;
	}

	fd_install(fd, f);
out:
	path_put(&path);

	return fd;
}

L
Linus Torvalds 已提交
2614 2615 2616
static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	struct sock *sk = sock->sk;
2617
	long amount = 0;
L
Linus Torvalds 已提交
2618 2619
	int err;

E
Eric Dumazet 已提交
2620 2621
	switch (cmd) {
	case SIOCOUTQ:
2622
		amount = unix_outq_len(sk);
E
Eric Dumazet 已提交
2623 2624 2625
		err = put_user(amount, (int __user *)arg);
		break;
	case SIOCINQ:
2626 2627 2628 2629
		amount = unix_inq_len(sk);
		if (amount < 0)
			err = amount;
		else
L
Linus Torvalds 已提交
2630
			err = put_user(amount, (int __user *)arg);
2631
		break;
2632 2633 2634
	case SIOCUNIXFILE:
		err = unix_open_file(sk);
		break;
E
Eric Dumazet 已提交
2635 2636 2637
	default:
		err = -ENOIOCTLCMD;
		break;
L
Linus Torvalds 已提交
2638 2639 2640 2641
	}
	return err;
}

E
Eric Dumazet 已提交
2642
static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
L
Linus Torvalds 已提交
2643 2644 2645 2646
{
	struct sock *sk = sock->sk;
	unsigned int mask;

E
Eric Dumazet 已提交
2647
	sock_poll_wait(file, sk_sleep(sk), wait);
L
Linus Torvalds 已提交
2648 2649 2650 2651 2652 2653 2654
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err)
		mask |= POLLERR;
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;
2655
	if (sk->sk_shutdown & RCV_SHUTDOWN)
E
Eric Dumazet 已提交
2656
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
L
Linus Torvalds 已提交
2657 2658

	/* readable? */
E
Eric Dumazet 已提交
2659
	if (!skb_queue_empty(&sk->sk_receive_queue))
L
Linus Torvalds 已提交
2660 2661 2662
		mask |= POLLIN | POLLRDNORM;

	/* Connection-based need to check for termination and startup */
E
Eric Dumazet 已提交
2663 2664
	if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
	    sk->sk_state == TCP_CLOSE)
L
Linus Torvalds 已提交
2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676
		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;
}

2677 2678
static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
				    poll_table *wait)
2679
{
2680 2681
	struct sock *sk = sock->sk, *other;
	unsigned int mask, writable;
2682

E
Eric Dumazet 已提交
2683
	sock_poll_wait(file, sk_sleep(sk), wait);
2684 2685 2686 2687
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2688
		mask |= POLLERR |
2689
			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2690

2691
	if (sk->sk_shutdown & RCV_SHUTDOWN)
2692
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2693 2694 2695 2696
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;

	/* readable? */
2697
	if (!skb_queue_empty(&sk->sk_receive_queue))
2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708
		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
2709
	/* No write status requested, avoid expensive OUT tests. */
2710
	if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
E
Eric Dumazet 已提交
2711 2712
		return mask;

2713
	writable = unix_writable(sk);
2714 2715 2716 2717 2718 2719 2720 2721 2722 2723
	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);
2724 2725 2726
	}

	if (writable)
2727 2728
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
	else
2729
		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
2730 2731 2732

	return mask;
}
L
Linus Torvalds 已提交
2733 2734

#ifdef CONFIG_PROC_FS
2735

E
Eric Dumazet 已提交
2736 2737 2738 2739 2740
#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))
2741

E
Eric Dumazet 已提交
2742
static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
L
Linus Torvalds 已提交
2743
{
E
Eric Dumazet 已提交
2744 2745 2746 2747
	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
2748

E
Eric Dumazet 已提交
2749 2750
	for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
		if (sock_net(sk) != seq_file_net(seq))
2751
			continue;
E
Eric Dumazet 已提交
2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770
		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
2771
	}
E
Eric Dumazet 已提交
2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782

	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
2783 2784 2785 2786
	return NULL;
}

static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2787
	__acquires(unix_table_lock)
L
Linus Torvalds 已提交
2788
{
2789
	spin_lock(&unix_table_lock);
E
Eric Dumazet 已提交
2790 2791 2792 2793 2794 2795 2796 2797

	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
2798 2799 2800 2801 2802
}

static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	++*pos;
E
Eric Dumazet 已提交
2803
	return unix_next_socket(seq, v, pos);
L
Linus Torvalds 已提交
2804 2805 2806
}

static void unix_seq_stop(struct seq_file *seq, void *v)
2807
	__releases(unix_table_lock)
L
Linus Torvalds 已提交
2808
{
2809
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
2810 2811 2812 2813
}

static int unix_seq_show(struct seq_file *seq, void *v)
{
2814

J
Joe Perches 已提交
2815
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
2816 2817 2818 2819 2820
		seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
			 "Inode Path\n");
	else {
		struct sock *s = v;
		struct unix_sock *u = unix_sk(s);
2821
		unix_state_lock(s);
L
Linus Torvalds 已提交
2822

D
Dan Rosenberg 已提交
2823
		seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
L
Linus Torvalds 已提交
2824
			s,
2825
			refcount_read(&s->sk_refcnt),
L
Linus Torvalds 已提交
2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846
			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++)
2847 2848
				seq_putc(seq, u->addr->name->sun_path[i] ?:
					 '@');
L
Linus Torvalds 已提交
2849
		}
2850
		unix_state_unlock(s);
L
Linus Torvalds 已提交
2851 2852 2853 2854 2855 2856
		seq_putc(seq, '\n');
	}

	return 0;
}

2857
static const struct seq_operations unix_seq_ops = {
L
Linus Torvalds 已提交
2858 2859 2860 2861 2862 2863 2864 2865
	.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)
{
2866
	return seq_open_net(inode, file, &unix_seq_ops,
E
Eric Dumazet 已提交
2867
			    sizeof(struct seq_net_private));
L
Linus Torvalds 已提交
2868 2869
}

2870
static const struct file_operations unix_seq_fops = {
L
Linus Torvalds 已提交
2871 2872 2873 2874
	.owner		= THIS_MODULE,
	.open		= unix_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
2875
	.release	= seq_release_net,
L
Linus Torvalds 已提交
2876 2877 2878 2879
};

#endif

2880
static const struct net_proto_family unix_family_ops = {
L
Linus Torvalds 已提交
2881 2882 2883 2884 2885
	.family = PF_UNIX,
	.create = unix_create,
	.owner	= THIS_MODULE,
};

2886

2887
static int __net_init unix_net_init(struct net *net)
2888 2889 2890
{
	int error = -ENOMEM;

2891
	net->unx.sysctl_max_dgram_qlen = 10;
2892 2893
	if (unix_sysctl_register(net))
		goto out;
2894

2895
#ifdef CONFIG_PROC_FS
2896
	if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2897
		unix_sysctl_unregister(net);
2898
		goto out;
2899
	}
2900 2901 2902
#endif
	error = 0;
out:
2903
	return error;
2904 2905
}

2906
static void __net_exit unix_net_exit(struct net *net)
2907
{
2908
	unix_sysctl_unregister(net);
2909
	remove_proc_entry("unix", net->proc_net);
2910 2911 2912 2913 2914 2915 2916
}

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

L
Linus Torvalds 已提交
2917 2918 2919 2920
static int __init af_unix_init(void)
{
	int rc = -1;

2921
	BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
L
Linus Torvalds 已提交
2922 2923

	rc = proto_register(&unix_proto, 1);
2924
	if (rc != 0) {
W
wangweidong 已提交
2925
		pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
L
Linus Torvalds 已提交
2926 2927 2928 2929
		goto out;
	}

	sock_register(&unix_family_ops);
2930
	register_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2931 2932 2933 2934 2935 2936 2937 2938
out:
	return rc;
}

static void __exit af_unix_exit(void)
{
	sock_unregister(PF_UNIX);
	proto_unregister(&unix_proto);
2939
	unregister_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2940 2941
}

2942 2943 2944 2945 2946
/* 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
2947 2948 2949 2950
module_exit(af_unix_exit);

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