af_unix.c 57.4 KB
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/*
 * NET4:	Implementation of BSD Unix domain sockets.
 *
4
 * Authors:	Alan Cox, <alan@lxorguk.ukuu.org.uk>
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 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 * Fixes:
 *		Linus Torvalds	:	Assorted bug cures.
 *		Niibe Yutaka	:	async I/O support.
 *		Carsten Paeth	:	PF_UNIX check, address fixes.
 *		Alan Cox	:	Limit size of allocated blocks.
 *		Alan Cox	:	Fixed the stupid socketpair bug.
 *		Alan Cox	:	BSD compatibility fine tuning.
 *		Alan Cox	:	Fixed a bug in connect when interrupted.
 *		Alan Cox	:	Sorted out a proper draft version of
 *					file descriptor passing hacked up from
 *					Mike Shaver's work.
 *		Marty Leisner	:	Fixes to fd passing
 *		Nick Nevin	:	recvmsg bugfix.
 *		Alan Cox	:	Started proper garbage collector
 *		Heiko EiBfeldt	:	Missing verify_area check
 *		Alan Cox	:	Started POSIXisms
 *		Andreas Schwab	:	Replace inode by dentry for proper
 *					reference counting
 *		Kirk Petersen	:	Made this a module
 *	    Christoph Rohland	:	Elegant non-blocking accept/connect algorithm.
 *					Lots of bug fixes.
 *	     Alexey Kuznetosv	:	Repaired (I hope) bugs introduces
 *					by above two patches.
 *	     Andrea Arcangeli	:	If possible we block in connect(2)
 *					if the max backlog of the listen socket
 *					is been reached. This won't break
 *					old apps and it will avoid huge amount
 *					of socks hashed (this for unix_gc()
 *					performances reasons).
 *					Security fix that limits the max
 *					number of socks to 2*max_files and
 *					the number of skb queueable in the
 *					dgram receiver.
 *		Artur Skawina   :	Hash function optimizations
 *	     Alexey Kuznetsov   :	Full scale SMP. Lot of bugs are introduced 8)
 *	      Malcolm Beattie   :	Set peercred for socketpair
 *	     Michal Ostrowski   :       Module initialization cleanup.
 *	     Arnaldo C. Melo	:	Remove MOD_{INC,DEC}_USE_COUNT,
 *	     				the core infrastructure is doing that
 *	     				for all net proto families now (2.5.69+)
 *
 *
 * Known differences from reference BSD that was tested:
 *
 *	[TO FIX]
 *	ECONNREFUSED is not returned from one end of a connected() socket to the
 *		other the moment one end closes.
 *	fstat() doesn't return st_dev=0, and give the blksize as high water mark
 *		and a fake inode identifier (nor the BSD first socket fstat twice bug).
 *	[NOT TO FIX]
 *	accept() returns a path name even if the connecting socket has closed
 *		in the meantime (BSD loses the path and gives up).
 *	accept() returns 0 length path for an unbound connector. BSD returns 16
 *		and a null first byte in the path (but not for gethost/peername - BSD bug ??)
 *	socketpair(...SOCK_RAW..) doesn't panic the kernel.
 *	BSD af_unix apparently has connect forgetting to block properly.
 *		(need to check this with the POSIX spec in detail)
 *
 * Differences from 2.0.0-11-... (ANK)
 *	Bug fixes and improvements.
 *		- client shutdown killed server socket.
 *		- removed all useless cli/sti pairs.
 *
 *	Semantic changes/extensions.
 *		- generic control message passing.
 *		- SCM_CREDENTIALS control message.
 *		- "Abstract" (not FS based) socket bindings.
 *		  Abstract names are sequences of bytes (not zero terminated)
 *		  started by 0, so that this name space does not intersect
 *		  with BSD names.
 */

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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

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

#define UNIX_ABSTRACT(sk)	(unix_sk(sk)->addr->hash < UNIX_HASH_SIZE)
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#ifdef CONFIG_SECURITY_NETWORK
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static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
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{
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	memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
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}

static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
{
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	scm->secid = *UNIXSID(skb);
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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)
{ }
#endif /* CONFIG_SECURITY_NETWORK */

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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	spin_lock(&unix_table_lock);
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	sk_for_each(s,
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		    &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
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		struct dentry *dentry = unix_sk(s)->path.dentry;
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		if (dentry && dentry->d_inode == 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;
}

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

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);
		if (wq_has_sleeper(wq))
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			wake_up_interruptible_sync_poll(&wq->wait,
				POLLOUT | POLLWRNORM | POLLWRBAND);
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		sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
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	}
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	rcu_read_unlock();
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}

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

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

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

	skb_queue_purge(&sk->sk_receive_queue);

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

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

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

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

	unix_remove_socket(sk);

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

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

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

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

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	if (path.dentry)
		path_put(&path);
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	sock_put(sk);

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

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

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	if (unix_tot_inflight)
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		unix_gc();		/* Garbage collect fds */
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}

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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);
}

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static int unix_listen(struct socket *sock, int backlog)
{
	int err;
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
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	struct pid *old_pid = NULL;
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	err = -EOPNOTSUPP;
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	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
		goto out;	/* Only stream/seqpacket sockets accept */
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	err = -EINVAL;
	if (!u->addr)
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		goto out;	/* No listens on an unbound socket */
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	unix_state_lock(sk);
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	if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
		goto out_unlock;
	if (backlog > sk->sk_max_ack_backlog)
		wake_up_interruptible_all(&u->peer_wait);
	sk->sk_max_ack_backlog	= backlog;
	sk->sk_state		= TCP_LISTEN;
	/* set credentials so connect can copy them */
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	init_peercred(sk);
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	err = 0;

out_unlock:
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	unix_state_unlock(sk);
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	put_pid(old_pid);
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out:
	return err;
}

static int unix_release(struct socket *);
static int unix_bind(struct socket *, struct sockaddr *, int);
static int unix_stream_connect(struct socket *, struct sockaddr *,
			       int addr_len, int flags);
static int unix_socketpair(struct socket *, struct socket *);
static int unix_accept(struct socket *, struct socket *, int);
static int unix_getname(struct socket *, struct sockaddr *, int *, int);
static unsigned int unix_poll(struct file *, struct socket *, poll_table *);
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static unsigned int unix_dgram_poll(struct file *, struct socket *,
				    poll_table *);
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static int unix_ioctl(struct socket *, unsigned int, unsigned long);
static int unix_shutdown(struct socket *, int);
static int unix_stream_sendmsg(struct kiocb *, struct socket *,
			       struct msghdr *, size_t);
static int unix_stream_recvmsg(struct kiocb *, struct socket *,
			       struct msghdr *, size_t, int);
static int unix_dgram_sendmsg(struct kiocb *, struct socket *,
			      struct msghdr *, size_t);
static int unix_dgram_recvmsg(struct kiocb *, struct socket *,
			      struct msghdr *, size_t, int);
static int unix_dgram_connect(struct socket *, struct sockaddr *,
			      int, int);
static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
				  struct msghdr *, size_t);
531 532
static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
				  struct msghdr *, size_t, int);
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534
static int unix_set_peek_off(struct sock *sk, int val)
535 536 537
{
	struct unix_sock *u = unix_sk(sk);

538 539 540
	if (mutex_lock_interruptible(&u->readlock))
		return -EINTR;

541 542
	sk->sk_peek_off = val;
	mutex_unlock(&u->readlock);
543 544

	return 0;
545 546 547
}


548
static const struct proto_ops unix_stream_ops = {
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	.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,
	.sendpage =	sock_no_sendpage,
567
	.set_peek_off =	unix_set_peek_off,
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};

570
static const struct proto_ops unix_dgram_ops = {
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	.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,
579
	.poll =		unix_dgram_poll,
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	.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,
589
	.set_peek_off =	unix_set_peek_off,
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};

592
static const struct proto_ops unix_seqpacket_ops = {
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	.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,
601
	.poll =		unix_dgram_poll,
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	.ioctl =	unix_ioctl,
	.listen =	unix_listen,
	.shutdown =	unix_shutdown,
	.setsockopt =	sock_no_setsockopt,
	.getsockopt =	sock_no_getsockopt,
	.sendmsg =	unix_seqpacket_sendmsg,
608
	.recvmsg =	unix_seqpacket_recvmsg,
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	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
611
	.set_peek_off =	unix_set_peek_off,
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};

static struct proto unix_proto = {
615 616 617
	.name			= "UNIX",
	.owner			= THIS_MODULE,
	.obj_size		= sizeof(struct unix_sock),
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};

620 621 622 623 624 625 626 627
/*
 * 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;

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static struct sock *unix_create1(struct net *net, struct socket *sock)
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{
	struct sock *sk = NULL;
	struct unix_sock *u;

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	atomic_long_inc(&unix_nr_socks);
	if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
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		goto out;

637
	sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
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	if (!sk)
		goto out;

E
Eric Dumazet 已提交
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	sock_init_data(sock, sk);
642 643
	lockdep_set_class(&sk->sk_receive_queue.lock,
				&af_unix_sk_receive_queue_lock_key);
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	sk->sk_write_space	= unix_write_space;
646
	sk->sk_max_ack_backlog	= net->unx.sysctl_max_dgram_qlen;
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	sk->sk_destruct		= unix_sock_destructor;
	u	  = unix_sk(sk);
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	u->path.dentry = NULL;
	u->path.mnt = NULL;
651
	spin_lock_init(&u->lock);
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	atomic_long_set(&u->inflight, 0);
653
	INIT_LIST_HEAD(&u->link);
I
Ingo Molnar 已提交
654
	mutex_init(&u->readlock); /* single task reading lock */
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	init_waitqueue_head(&u->peer_wait);
E
Eric Dumazet 已提交
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	unix_insert_socket(unix_sockets_unbound(sk), sk);
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out:
658
	if (sk == NULL)
E
Eric Dumazet 已提交
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		atomic_long_dec(&unix_nr_socks);
660 661
	else {
		local_bh_disable();
662
		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
663 664
		local_bh_enable();
	}
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	return sk;
}

668 669
static int unix_create(struct net *net, struct socket *sock, int protocol,
		       int kern)
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{
	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:
685
		sock->type = SOCK_DGRAM;
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	case SOCK_DGRAM:
		sock->ops = &unix_dgram_ops;
		break;
	case SOCK_SEQPACKET:
		sock->ops = &unix_seqpacket_ops;
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}

696
	return unix_create1(net, sock) ? 0 : -ENOMEM;
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}

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

	if (!sk)
		return 0;

706
	unix_release_sock(sk, 0);
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	sock->sk = NULL;

709
	return 0;
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}

static int unix_autobind(struct socket *sock)
{
	struct sock *sk = sock->sk;
715
	struct net *net = sock_net(sk);
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	struct unix_sock *u = unix_sk(sk);
	static u32 ordernum = 1;
E
Eric Dumazet 已提交
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	struct unix_address *addr;
L
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719
	int err;
720
	unsigned int retries = 0;
L
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721

722 723 724
	err = mutex_lock_interruptible(&u->readlock);
	if (err)
		return err;
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	err = 0;
	if (u->addr)
		goto out;

	err = -ENOMEM;
731
	addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
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	if (!addr)
		goto out;

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

retry:
	addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
740
	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
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741

742
	spin_lock(&unix_table_lock);
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	ordernum = (ordernum+1)&0xFFFFF;

745
	if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
L
Linus Torvalds 已提交
746
				      addr->hash)) {
747
		spin_unlock(&unix_table_lock);
748 749 750 751 752 753 754 755 756 757 758
		/*
		 * __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;
		}
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		goto retry;
	}
	addr->hash ^= sk->sk_type;

	__unix_remove_socket(sk);
	u->addr = addr;
	__unix_insert_socket(&unix_socket_table[addr->hash], sk);
766
	spin_unlock(&unix_table_lock);
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	err = 0;

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out:	mutex_unlock(&u->readlock);
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	return err;
}

773 774
static struct sock *unix_find_other(struct net *net,
				    struct sockaddr_un *sunname, int len,
775
				    int type, unsigned int hash, int *error)
L
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{
	struct sock *u;
778
	struct path path;
L
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779
	int err = 0;
780

L
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	if (sunname->sun_path[0]) {
782 783
		struct inode *inode;
		err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
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		if (err)
			goto fail;
786 787
		inode = path.dentry->d_inode;
		err = inode_permission(inode, MAY_WRITE);
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		if (err)
			goto put_fail;

		err = -ECONNREFUSED;
792
		if (!S_ISSOCK(inode->i_mode))
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			goto put_fail;
794
		u = unix_find_socket_byinode(inode);
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		if (!u)
			goto put_fail;

		if (u->sk_type == type)
A
Al Viro 已提交
799
			touch_atime(&path);
L
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800

801
		path_put(&path);
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802

803
		err = -EPROTOTYPE;
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		if (u->sk_type != type) {
			sock_put(u);
			goto fail;
		}
	} else {
		err = -ECONNREFUSED;
810
		u = unix_find_socket_byname(net, sunname, len, type, hash);
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		if (u) {
			struct dentry *dentry;
A
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			dentry = unix_sk(u)->path.dentry;
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			if (dentry)
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Al Viro 已提交
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				touch_atime(&unix_sk(u)->path);
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		} else
			goto fail;
	}
	return u;

put_fail:
822
	path_put(&path);
L
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fail:
824
	*error = err;
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	return NULL;
}

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Al Viro 已提交
828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855
static int unix_mknod(const char *sun_path, umode_t mode, struct path *res)
{
	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;

	/*
	 * All right, let's create it.
	 */
	err = security_path_mknod(&path, dentry, mode, 0);
	if (!err) {
		err = vfs_mknod(path.dentry->d_inode, dentry, mode, 0);
		if (!err) {
			res->mnt = mntget(path.mnt);
			res->dentry = dget(dentry);
		}
	}
	done_path_create(&path, dentry);
	return err;
}
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static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
	struct sock *sk = sock->sk;
860
	struct net *net = sock_net(sk);
L
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	struct unix_sock *u = unix_sk(sk);
862
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
863
	char *sun_path = sunaddr->sun_path;
L
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864
	int err;
865
	unsigned int hash;
L
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	struct unix_address *addr;
	struct hlist_head *list;

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

873
	if (addr_len == sizeof(short)) {
L
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		err = unix_autobind(sock);
		goto out;
	}

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

883 884 885
	err = mutex_lock_interruptible(&u->readlock);
	if (err)
		goto out;
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886 887 888 889 890 891 892 893 894 895 896 897 898 899 900

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

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

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

901
	if (sun_path[0]) {
A
Al Viro 已提交
902 903
		struct path path;
		umode_t mode = S_IFSOCK |
A
Al Viro 已提交
904
		       (SOCK_INODE(sock)->i_mode & ~current_umask());
A
Al Viro 已提交
905 906 907 908 909 910 911
		err = unix_mknod(sun_path, mode, &path);
		if (err) {
			if (err == -EEXIST)
				err = -EADDRINUSE;
			unix_release_addr(addr);
			goto out_up;
		}
L
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912
		addr->hash = UNIX_HASH_SIZE;
A
Al Viro 已提交
913 914 915 916 917 918
		hash = path.dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1);
		spin_lock(&unix_table_lock);
		u->path = path;
		list = &unix_socket_table[hash];
	} else {
		spin_lock(&unix_table_lock);
L
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919
		err = -EADDRINUSE;
920
		if (__unix_find_socket_byname(net, sunaddr, addr_len,
L
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921 922 923 924 925 926 927 928 929 930 931 932 933 934
					      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:
935
	spin_unlock(&unix_table_lock);
L
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out_up:
I
Ingo Molnar 已提交
937
	mutex_unlock(&u->readlock);
L
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938 939 940 941
out:
	return err;
}

942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966
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);
}

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static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
			      int alen, int flags)
{
	struct sock *sk = sock->sk;
971
	struct net *net = sock_net(sk);
972
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
L
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973
	struct sock *other;
974
	unsigned int hash;
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975 976 977 978 979 980 981 982 983 984 985 986
	int err;

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

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

987
restart:
988
		other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
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989 990 991
		if (!other)
			goto out;

992 993 994 995 996 997 998 999
		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;
		}
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1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013

		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;
1014
		unix_state_double_lock(sk, other);
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1015 1016 1017 1018 1019 1020 1021
	}

	/*
	 * If it was connected, reconnect.
	 */
	if (unix_peer(sk)) {
		struct sock *old_peer = unix_peer(sk);
1022
		unix_peer(sk) = other;
1023
		unix_state_double_unlock(sk, other);
L
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1024 1025 1026 1027 1028

		if (other != old_peer)
			unix_dgram_disconnected(sk, old_peer);
		sock_put(old_peer);
	} else {
1029
		unix_peer(sk) = other;
1030
		unix_state_double_unlock(sk, other);
L
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1031
	}
1032
	return 0;
L
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1033 1034

out_unlock:
1035
	unix_state_double_unlock(sk, other);
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1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050
	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) &&
1051
		unix_recvq_full(other);
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1052

1053
	unix_state_unlock(other);
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1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064

	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)
{
1065
	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
L
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1066
	struct sock *sk = sock->sk;
1067
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1068 1069 1070 1071
	struct unix_sock *u = unix_sk(sk), *newu, *otheru;
	struct sock *newsk = NULL;
	struct sock *other = NULL;
	struct sk_buff *skb = NULL;
1072
	unsigned int hash;
L
Linus Torvalds 已提交
1073 1074 1075 1076 1077 1078 1079 1080 1081
	int st;
	int err;
	long timeo;

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

1082 1083
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
	    (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095
		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 */
1096
	newsk = unix_create1(sock_net(sk), NULL);
L
Linus Torvalds 已提交
1097 1098 1099 1100 1101 1102 1103 1104 1105 1106
	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. */
1107
	other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
L
Linus Torvalds 已提交
1108 1109 1110 1111
	if (!other)
		goto out;

	/* Latch state of peer */
1112
	unix_state_lock(other);
L
Linus Torvalds 已提交
1113 1114 1115

	/* Apparently VFS overslept socket death. Retry. */
	if (sock_flag(other, SOCK_DEAD)) {
1116
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1117 1118 1119 1120 1121 1122 1123
		sock_put(other);
		goto restart;
	}

	err = -ECONNREFUSED;
	if (other->sk_state != TCP_LISTEN)
		goto out_unlock;
1124 1125
	if (other->sk_shutdown & RCV_SHUTDOWN)
		goto out_unlock;
L
Linus Torvalds 已提交
1126

1127
	if (unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138
		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;
1139
	}
L
Linus Torvalds 已提交
1140 1141 1142

	/* Latch our state.

D
Daniel Baluta 已提交
1143
	   It is tricky place. We need to grab our state lock and cannot
L
Linus Torvalds 已提交
1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166
	   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;
	}

1167
	unix_state_lock_nested(sk);
L
Linus Torvalds 已提交
1168 1169

	if (sk->sk_state != st) {
1170 1171
		unix_state_unlock(sk);
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1172 1173 1174 1175
		sock_put(other);
		goto restart;
	}

1176
	err = security_unix_stream_connect(sk, other, newsk);
L
Linus Torvalds 已提交
1177
	if (err) {
1178
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
1179 1180 1181 1182 1183 1184 1185 1186 1187
		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;
1188
	init_peercred(newsk);
L
Linus Torvalds 已提交
1189
	newu = unix_sk(newsk);
1190
	RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
L
Linus Torvalds 已提交
1191 1192 1193 1194 1195 1196 1197
	otheru = unix_sk(other);

	/* copy address information from listening to new sock*/
	if (otheru->addr) {
		atomic_inc(&otheru->addr->refcnt);
		newu->addr = otheru->addr;
	}
A
Al Viro 已提交
1198 1199 1200
	if (otheru->path.dentry) {
		path_get(&otheru->path);
		newu->path = otheru->path;
L
Linus Torvalds 已提交
1201 1202 1203
	}

	/* Set credentials */
1204
	copy_peercred(sk, other);
L
Linus Torvalds 已提交
1205 1206 1207

	sock->state	= SS_CONNECTED;
	sk->sk_state	= TCP_ESTABLISHED;
1208 1209
	sock_hold(newsk);

1210
	smp_mb__after_atomic();	/* sock_hold() does an atomic_inc() */
1211
	unix_peer(sk)	= newsk;
L
Linus Torvalds 已提交
1212

1213
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1214 1215 1216 1217 1218

	/* 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);
1219
	unix_state_unlock(other);
1220
	other->sk_data_ready(other);
L
Linus Torvalds 已提交
1221 1222 1223 1224 1225
	sock_put(other);
	return 0;

out_unlock:
	if (other)
1226
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1227 1228

out:
1229
	kfree_skb(skb);
L
Linus Torvalds 已提交
1230 1231 1232 1233 1234 1235 1236 1237 1238
	if (newsk)
		unix_release_sock(newsk, 0);
	if (other)
		sock_put(other);
	return err;
}

static int unix_socketpair(struct socket *socka, struct socket *sockb)
{
1239
	struct sock *ska = socka->sk, *skb = sockb->sk;
L
Linus Torvalds 已提交
1240 1241 1242 1243

	/* Join our sockets back to back */
	sock_hold(ska);
	sock_hold(skb);
1244 1245
	unix_peer(ska) = skb;
	unix_peer(skb) = ska;
1246 1247
	init_peercred(ska);
	init_peercred(skb);
L
Linus Torvalds 已提交
1248 1249 1250 1251 1252 1253 1254 1255 1256 1257

	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;
}

1258 1259 1260 1261 1262 1263 1264 1265 1266
static void unix_sock_inherit_flags(const struct socket *old,
				    struct socket *new)
{
	if (test_bit(SOCK_PASSCRED, &old->flags))
		set_bit(SOCK_PASSCRED, &new->flags);
	if (test_bit(SOCK_PASSSEC, &old->flags))
		set_bit(SOCK_PASSSEC, &new->flags);
}

L
Linus Torvalds 已提交
1267 1268 1269 1270 1271 1272 1273 1274
static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
{
	struct sock *sk = sock->sk;
	struct sock *tsk;
	struct sk_buff *skb;
	int err;

	err = -EOPNOTSUPP;
E
Eric Dumazet 已提交
1275
	if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
L
Linus Torvalds 已提交
1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298
		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 */
1299
	unix_state_lock(tsk);
L
Linus Torvalds 已提交
1300
	newsock->state = SS_CONNECTED;
1301
	unix_sock_inherit_flags(sock, newsock);
L
Linus Torvalds 已提交
1302
	sock_graft(tsk, newsock);
1303
	unix_state_unlock(tsk);
L
Linus Torvalds 已提交
1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314
	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;
1315
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
L
Linus Torvalds 已提交
1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329
	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);
1330
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1331 1332 1333 1334 1335 1336 1337 1338 1339 1340
	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);
	}
1341
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353
	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
1354
	for (i = scm->fp->count-1; i >= 0; i--)
L
Linus Torvalds 已提交
1355 1356 1357
		unix_notinflight(scm->fp->fp[i]);
}

1358
static void unix_destruct_scm(struct sk_buff *skb)
L
Linus Torvalds 已提交
1359 1360 1361
{
	struct scm_cookie scm;
	memset(&scm, 0, sizeof(scm));
1362 1363 1364
	scm.pid  = UNIXCB(skb).pid;
	if (UNIXCB(skb).fp)
		unix_detach_fds(&scm, skb);
L
Linus Torvalds 已提交
1365 1366 1367 1368 1369 1370 1371

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

E
Eric Dumazet 已提交
1372 1373
#define MAX_RECURSION_LEVEL 4

1374
static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
L
Linus Torvalds 已提交
1375 1376
{
	int i;
E
Eric Dumazet 已提交
1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390
	unsigned char max_level = 0;
	int unix_sock_count = 0;

	for (i = scm->fp->count - 1; i >= 0; i--) {
		struct sock *sk = unix_get_socket(scm->fp->fp[i]);

		if (sk) {
			unix_sock_count++;
			max_level = max(max_level,
					unix_sk(sk)->recursion_level);
		}
	}
	if (unlikely(max_level > MAX_RECURSION_LEVEL))
		return -ETOOMANYREFS;
1391 1392 1393 1394 1395 1396 1397 1398 1399 1400

	/*
	 * 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;

E
Eric Dumazet 已提交
1401 1402 1403 1404 1405
	if (unix_sock_count) {
		for (i = scm->fp->count - 1; i >= 0; i--)
			unix_inflight(scm->fp->fp[i]);
	}
	return max_level;
L
Linus Torvalds 已提交
1406 1407
}

1408
static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
1409 1410
{
	int err = 0;
1411

1412
	UNIXCB(skb).pid  = get_pid(scm->pid);
1413 1414
	UNIXCB(skb).uid = scm->creds.uid;
	UNIXCB(skb).gid = scm->creds.gid;
1415 1416 1417 1418 1419 1420 1421 1422
	UNIXCB(skb).fp = NULL;
	if (scm->fp && send_fds)
		err = unix_attach_fds(scm, skb);

	skb->destructor = unix_destruct_scm;
	return err;
}

1423 1424 1425 1426 1427 1428 1429 1430
/*
 * 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)
{
1431
	if (UNIXCB(skb).pid)
1432 1433
		return;
	if (test_bit(SOCK_PASSCRED, &sock->flags) ||
1434 1435
	    !other->sk_socket ||
	    test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
1436
		UNIXCB(skb).pid  = get_pid(task_tgid(current));
1437
		current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
1438 1439 1440
	}
}

L
Linus Torvalds 已提交
1441 1442 1443 1444 1445 1446 1447 1448 1449
/*
 *	Send AF_UNIX data.
 */

static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
			      struct msghdr *msg, size_t len)
{
	struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
	struct sock *sk = sock->sk;
1450
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
1451
	struct unix_sock *u = unix_sk(sk);
1452
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
L
Linus Torvalds 已提交
1453 1454 1455
	struct sock *other = NULL;
	int namelen = 0; /* fake GCC */
	int err;
1456
	unsigned int hash;
1457
	struct sk_buff *skb;
L
Linus Torvalds 已提交
1458 1459
	long timeo;
	struct scm_cookie tmp_scm;
E
Eric Dumazet 已提交
1460
	int max_level;
1461
	int data_len = 0;
L
Linus Torvalds 已提交
1462 1463 1464

	if (NULL == siocb->scm)
		siocb->scm = &tmp_scm;
1465
	wait_for_unix_gc();
1466
	err = scm_send(sock, msg, siocb->scm, false);
L
Linus Torvalds 已提交
1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486
	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;
	}

1487 1488
	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
	    && (err = unix_autobind(sock)) != 0)
L
Linus Torvalds 已提交
1489 1490 1491 1492 1493 1494
		goto out;

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

1495
	if (len > SKB_MAX_ALLOC) {
1496 1497 1498
		data_len = min_t(size_t,
				 len - SKB_MAX_ALLOC,
				 MAX_SKB_FRAGS * PAGE_SIZE);
1499 1500 1501 1502
		data_len = PAGE_ALIGN(data_len);

		BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
	}
1503 1504

	skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
1505 1506
				   msg->msg_flags & MSG_DONTWAIT, &err,
				   PAGE_ALLOC_COSTLY_ORDER);
1507
	if (skb == NULL)
L
Linus Torvalds 已提交
1508 1509
		goto out;

1510
	err = unix_scm_to_skb(siocb->scm, skb, true);
E
Eric Dumazet 已提交
1511
	if (err < 0)
1512
		goto out_free;
E
Eric Dumazet 已提交
1513
	max_level = err + 1;
1514
	unix_get_secdata(siocb->scm, skb);
C
Catherine Zhang 已提交
1515

1516 1517 1518
	skb_put(skb, len - data_len);
	skb->data_len = data_len;
	skb->len = len;
A
Al Viro 已提交
1519
	err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
L
Linus Torvalds 已提交
1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530
	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;

1531
		other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
L
Linus Torvalds 已提交
1532
					hash, &err);
1533
		if (other == NULL)
L
Linus Torvalds 已提交
1534 1535 1536
			goto out_free;
	}

A
Alban Crequy 已提交
1537 1538 1539 1540 1541 1542
	if (sk_filter(other, skb) < 0) {
		/* Toss the packet but do not return any error to the sender */
		err = len;
		goto out_free;
	}

1543
	unix_state_lock(other);
L
Linus Torvalds 已提交
1544 1545 1546 1547 1548 1549 1550 1551 1552
	err = -EPERM;
	if (!unix_may_send(sk, other))
		goto out_unlock;

	if (sock_flag(other, SOCK_DEAD)) {
		/*
		 *	Check with 1003.1g - what should
		 *	datagram error
		 */
1553
		unix_state_unlock(other);
L
Linus Torvalds 已提交
1554 1555 1556
		sock_put(other);

		err = 0;
1557
		unix_state_lock(sk);
L
Linus Torvalds 已提交
1558
		if (unix_peer(sk) == other) {
1559
			unix_peer(sk) = NULL;
1560
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1561 1562 1563 1564 1565

			unix_dgram_disconnected(sk, other);
			sock_put(other);
			err = -ECONNREFUSED;
		} else {
1566
			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584
		}

		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;
	}

1585
	if (unix_peer(other) != sk && unix_recvq_full(other)) {
L
Linus Torvalds 已提交
1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599
		if (!timeo) {
			err = -EAGAIN;
			goto out_unlock;
		}

		timeo = unix_wait_for_peer(other, timeo);

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

		goto restart;
	}

1600 1601
	if (sock_flag(other, SOCK_RCVTSTAMP))
		__net_timestamp(skb);
1602
	maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1603
	skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1604 1605
	if (max_level > unix_sk(other)->recursion_level)
		unix_sk(other)->recursion_level = max_level;
1606
	unix_state_unlock(other);
1607
	other->sk_data_ready(other);
L
Linus Torvalds 已提交
1608
	sock_put(other);
1609
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1610 1611 1612
	return len;

out_unlock:
1613
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1614 1615 1616 1617 1618
out_free:
	kfree_skb(skb);
out:
	if (other)
		sock_put(other);
1619
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1620 1621 1622
	return err;
}

1623 1624 1625 1626
/* 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))
1627

L
Linus Torvalds 已提交
1628 1629 1630 1631 1632 1633
static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
			       struct msghdr *msg, size_t len)
{
	struct sock_iocb *siocb = kiocb_to_siocb(kiocb);
	struct sock *sk = sock->sk;
	struct sock *other = NULL;
E
Eric Dumazet 已提交
1634
	int err, size;
1635
	struct sk_buff *skb;
1636
	int sent = 0;
L
Linus Torvalds 已提交
1637
	struct scm_cookie tmp_scm;
1638
	bool fds_sent = false;
E
Eric Dumazet 已提交
1639
	int max_level;
1640
	int data_len;
L
Linus Torvalds 已提交
1641 1642 1643

	if (NULL == siocb->scm)
		siocb->scm = &tmp_scm;
1644
	wait_for_unix_gc();
1645
	err = scm_send(sock, msg, siocb->scm, false);
L
Linus Torvalds 已提交
1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657
	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;
1658
		other = unix_peer(sk);
L
Linus Torvalds 已提交
1659 1660 1661 1662 1663 1664 1665
		if (!other)
			goto out_err;
	}

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

E
Eric Dumazet 已提交
1666
	while (sent < len) {
1667
		size = len - sent;
L
Linus Torvalds 已提交
1668 1669

		/* Keep two messages in the pipe so it schedules better */
1670
		size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
L
Linus Torvalds 已提交
1671

1672 1673
		/* allow fallback to order-0 allocations */
		size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
1674

1675
		data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
L
Linus Torvalds 已提交
1676

1677 1678
		data_len = min_t(size_t, size, PAGE_ALIGN(data_len));

1679
		skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
1680 1681
					   msg->msg_flags & MSG_DONTWAIT, &err,
					   get_order(UNIX_SKB_FRAGS_SZ));
1682
		if (!skb)
L
Linus Torvalds 已提交
1683 1684
			goto out_err;

1685 1686
		/* Only send the fds in the first buffer */
		err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
E
Eric Dumazet 已提交
1687
		if (err < 0) {
1688
			kfree_skb(skb);
1689
			goto out_err;
1690
		}
E
Eric Dumazet 已提交
1691
		max_level = err + 1;
1692
		fds_sent = true;
L
Linus Torvalds 已提交
1693

1694 1695 1696
		skb_put(skb, size - data_len);
		skb->data_len = data_len;
		skb->len = size;
A
Al Viro 已提交
1697
		err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
E
Eric Dumazet 已提交
1698
		if (err) {
L
Linus Torvalds 已提交
1699
			kfree_skb(skb);
1700
			goto out_err;
L
Linus Torvalds 已提交
1701 1702
		}

1703
		unix_state_lock(other);
L
Linus Torvalds 已提交
1704 1705 1706 1707 1708

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

1709
		maybe_add_creds(skb, sock, other);
L
Linus Torvalds 已提交
1710
		skb_queue_tail(&other->sk_receive_queue, skb);
E
Eric Dumazet 已提交
1711 1712
		if (max_level > unix_sk(other)->recursion_level)
			unix_sk(other)->recursion_level = max_level;
1713
		unix_state_unlock(other);
1714
		other->sk_data_ready(other);
1715
		sent += size;
L
Linus Torvalds 已提交
1716 1717
	}

1718
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1719 1720 1721 1722 1723
	siocb->scm = NULL;

	return sent;

pipe_err_free:
1724
	unix_state_unlock(other);
L
Linus Torvalds 已提交
1725 1726
	kfree_skb(skb);
pipe_err:
E
Eric Dumazet 已提交
1727 1728
	if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
L
Linus Torvalds 已提交
1729 1730
	err = -EPIPE;
out_err:
1731
	scm_destroy(siocb->scm);
L
Linus Torvalds 已提交
1732 1733 1734 1735 1736 1737 1738 1739 1740
	siocb->scm = NULL;
	return sent ? : err;
}

static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
				  struct msghdr *msg, size_t len)
{
	int err;
	struct sock *sk = sock->sk;
1741

L
Linus Torvalds 已提交
1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753
	err = sock_error(sk);
	if (err)
		return err;

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

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

	return unix_dgram_sendmsg(kiocb, sock, msg, len);
}
1754

1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766
static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
			      struct msghdr *msg, size_t size,
			      int flags)
{
	struct sock *sk = sock->sk;

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

	return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
}

L
Linus Torvalds 已提交
1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787
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);
	}
}

static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
			      struct msghdr *msg, size_t size,
			      int flags)
{
	struct sock_iocb *siocb = kiocb_to_siocb(iocb);
	struct scm_cookie tmp_scm;
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
	int noblock = flags & MSG_DONTWAIT;
	struct sk_buff *skb;
	int err;
1788
	int peeked, skip;
L
Linus Torvalds 已提交
1789 1790 1791 1792 1793

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

1794
	err = mutex_lock_interruptible(&u->readlock);
1795 1796 1797 1798 1799
	if (unlikely(err)) {
		/* recvmsg() in non blocking mode is supposed to return -EAGAIN
		 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
		 */
		err = noblock ? -EAGAIN : -ERESTARTSYS;
1800 1801
		goto out;
	}
L
Linus Torvalds 已提交
1802

1803 1804 1805
	skip = sk_peek_offset(sk, flags);

	skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err);
1806 1807 1808 1809 1810 1811 1812
	if (!skb) {
		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);
L
Linus Torvalds 已提交
1813
		goto out_unlock;
1814
	}
L
Linus Torvalds 已提交
1815

E
Eric Dumazet 已提交
1816 1817
	wake_up_interruptible_sync_poll(&u->peer_wait,
					POLLOUT | POLLWRNORM | POLLWRBAND);
L
Linus Torvalds 已提交
1818 1819 1820 1821

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

1822 1823 1824
	if (size > skb->len - skip)
		size = skb->len - skip;
	else if (size < skb->len - skip)
L
Linus Torvalds 已提交
1825 1826
		msg->msg_flags |= MSG_TRUNC;

1827
	err = skb_copy_datagram_msg(skb, skip, msg, size);
L
Linus Torvalds 已提交
1828 1829 1830
	if (err)
		goto out_free;

1831 1832 1833
	if (sock_flag(sk, SOCK_RCVTSTAMP))
		__sock_recv_timestamp(msg, sk, skb);

L
Linus Torvalds 已提交
1834 1835 1836 1837
	if (!siocb->scm) {
		siocb->scm = &tmp_scm;
		memset(&tmp_scm, 0, sizeof(tmp_scm));
	}
1838
	scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
C
Catherine Zhang 已提交
1839
	unix_set_secdata(siocb->scm, skb);
L
Linus Torvalds 已提交
1840

E
Eric Dumazet 已提交
1841
	if (!(flags & MSG_PEEK)) {
L
Linus Torvalds 已提交
1842 1843
		if (UNIXCB(skb).fp)
			unix_detach_fds(siocb->scm, skb);
1844 1845

		sk_peek_offset_bwd(sk, skb->len);
E
Eric Dumazet 已提交
1846
	} else {
L
Linus Torvalds 已提交
1847 1848 1849 1850 1851 1852
		/* 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)
1853 1854 1855 1856 1857

		   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
1858
		*/
1859 1860 1861

		sk_peek_offset_fwd(sk, size);

L
Linus Torvalds 已提交
1862 1863 1864
		if (UNIXCB(skb).fp)
			siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
	}
1865
	err = (flags & MSG_TRUNC) ? skb->len - skip : size;
L
Linus Torvalds 已提交
1866 1867 1868 1869

	scm_recv(sock, msg, siocb->scm, flags);

out_free:
E
Eric Dumazet 已提交
1870
	skb_free_datagram(sk, skb);
L
Linus Torvalds 已提交
1871
out_unlock:
I
Ingo Molnar 已提交
1872
	mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
1873 1874 1875 1876 1877
out:
	return err;
}

/*
1878
 *	Sleep until more data has arrived. But check for races..
L
Linus Torvalds 已提交
1879
 */
1880 1881
static long unix_stream_data_wait(struct sock *sk, long timeo,
				  struct sk_buff *last)
L
Linus Torvalds 已提交
1882 1883 1884
{
	DEFINE_WAIT(wait);

1885
	unix_state_lock(sk);
L
Linus Torvalds 已提交
1886 1887

	for (;;) {
E
Eric Dumazet 已提交
1888
		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
L
Linus Torvalds 已提交
1889

1890
		if (skb_peek_tail(&sk->sk_receive_queue) != last ||
L
Linus Torvalds 已提交
1891 1892 1893 1894 1895 1896 1897
		    sk->sk_err ||
		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
		    signal_pending(current) ||
		    !timeo)
			break;

		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
1898
		unix_state_unlock(sk);
1899
		timeo = freezable_schedule_timeout(timeo);
1900
		unix_state_lock(sk);
L
Linus Torvalds 已提交
1901 1902 1903
		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
	}

E
Eric Dumazet 已提交
1904
	finish_wait(sk_sleep(sk), &wait);
1905
	unix_state_unlock(sk);
L
Linus Torvalds 已提交
1906 1907 1908
	return timeo;
}

1909 1910 1911 1912 1913
static unsigned int unix_skb_len(const struct sk_buff *skb)
{
	return skb->len - UNIXCB(skb).consumed;
}

L
Linus Torvalds 已提交
1914 1915 1916 1917 1918 1919 1920 1921
static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
			       struct msghdr *msg, size_t size,
			       int flags)
{
	struct sock_iocb *siocb = kiocb_to_siocb(iocb);
	struct scm_cookie tmp_scm;
	struct sock *sk = sock->sk;
	struct unix_sock *u = unix_sk(sk);
1922
	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
L
Linus Torvalds 已提交
1923
	int copied = 0;
1924
	int noblock = flags & MSG_DONTWAIT;
L
Linus Torvalds 已提交
1925 1926 1927 1928
	int check_creds = 0;
	int target;
	int err = 0;
	long timeo;
1929
	int skip;
L
Linus Torvalds 已提交
1930 1931 1932 1933 1934 1935 1936 1937 1938 1939

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

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

	target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
1940
	timeo = sock_rcvtimeo(sk, noblock);
L
Linus Torvalds 已提交
1941 1942 1943 1944 1945 1946 1947 1948 1949 1950

	/* Lock the socket to prevent queue disordering
	 * while sleeps in memcpy_tomsg
	 */

	if (!siocb->scm) {
		siocb->scm = &tmp_scm;
		memset(&tmp_scm, 0, sizeof(tmp_scm));
	}

1951
	err = mutex_lock_interruptible(&u->readlock);
1952 1953 1954 1955 1956
	if (unlikely(err)) {
		/* recvmsg() in non blocking mode is supposed to return -EAGAIN
		 * sk_rcvtimeo is not honored by mutex_lock_interruptible()
		 */
		err = noblock ? -EAGAIN : -ERESTARTSYS;
1957 1958
		goto out;
	}
L
Linus Torvalds 已提交
1959

E
Eric Dumazet 已提交
1960
	do {
L
Linus Torvalds 已提交
1961
		int chunk;
1962
		struct sk_buff *skb, *last;
L
Linus Torvalds 已提交
1963

1964
		unix_state_lock(sk);
1965
		last = skb = skb_peek(&sk->sk_receive_queue);
1966
again:
E
Eric Dumazet 已提交
1967
		if (skb == NULL) {
E
Eric Dumazet 已提交
1968
			unix_sk(sk)->recursion_level = 0;
L
Linus Torvalds 已提交
1969
			if (copied >= target)
1970
				goto unlock;
L
Linus Torvalds 已提交
1971 1972 1973 1974

			/*
			 *	POSIX 1003.1g mandates this order.
			 */
1975

E
Eric Dumazet 已提交
1976 1977
			err = sock_error(sk);
			if (err)
1978
				goto unlock;
L
Linus Torvalds 已提交
1979
			if (sk->sk_shutdown & RCV_SHUTDOWN)
1980 1981 1982
				goto unlock;

			unix_state_unlock(sk);
L
Linus Torvalds 已提交
1983 1984 1985
			err = -EAGAIN;
			if (!timeo)
				break;
I
Ingo Molnar 已提交
1986
			mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
1987

1988
			timeo = unix_stream_data_wait(sk, timeo, last);
L
Linus Torvalds 已提交
1989

1990 1991
			if (signal_pending(current)
			    ||  mutex_lock_interruptible(&u->readlock)) {
L
Linus Torvalds 已提交
1992 1993 1994
				err = sock_intr_errno(timeo);
				goto out;
			}
1995

L
Linus Torvalds 已提交
1996
			continue;
1997 1998 1999
 unlock:
			unix_state_unlock(sk);
			break;
L
Linus Torvalds 已提交
2000
		}
2001

2002
		skip = sk_peek_offset(sk, flags);
2003 2004
		while (skip >= unix_skb_len(skb)) {
			skip -= unix_skb_len(skb);
2005
			last = skb;
2006
			skb = skb_peek_next(skb, &sk->sk_receive_queue);
2007 2008
			if (!skb)
				goto again;
2009 2010
		}

2011
		unix_state_unlock(sk);
L
Linus Torvalds 已提交
2012 2013 2014

		if (check_creds) {
			/* Never glue messages from different writers */
2015
			if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
2016 2017
			    !uid_eq(UNIXCB(skb).uid, siocb->scm->creds.uid) ||
			    !gid_eq(UNIXCB(skb).gid, siocb->scm->creds.gid))
L
Linus Torvalds 已提交
2018
				break;
2019
		} else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
L
Linus Torvalds 已提交
2020
			/* Copy credentials */
2021
			scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
L
Linus Torvalds 已提交
2022 2023 2024 2025
			check_creds = 1;
		}

		/* Copy address just once */
E
Eric Dumazet 已提交
2026
		if (sunaddr) {
L
Linus Torvalds 已提交
2027 2028 2029 2030
			unix_copy_addr(msg, skb->sk);
			sunaddr = NULL;
		}

2031
		chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
2032 2033
		if (skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip,
					  msg, chunk)) {
L
Linus Torvalds 已提交
2034 2035 2036 2037 2038 2039 2040 2041
			if (copied == 0)
				copied = -EFAULT;
			break;
		}
		copied += chunk;
		size -= chunk;

		/* Mark read part of skb as used */
E
Eric Dumazet 已提交
2042
		if (!(flags & MSG_PEEK)) {
2043
			UNIXCB(skb).consumed += chunk;
L
Linus Torvalds 已提交
2044

2045 2046
			sk_peek_offset_bwd(sk, chunk);

L
Linus Torvalds 已提交
2047 2048 2049
			if (UNIXCB(skb).fp)
				unix_detach_fds(siocb->scm, skb);

2050
			if (unix_skb_len(skb))
L
Linus Torvalds 已提交
2051 2052
				break;

2053
			skb_unlink(skb, &sk->sk_receive_queue);
2054
			consume_skb(skb);
L
Linus Torvalds 已提交
2055 2056 2057

			if (siocb->scm->fp)
				break;
E
Eric Dumazet 已提交
2058
		} else {
L
Linus Torvalds 已提交
2059 2060 2061 2062 2063
			/* It is questionable, see note in unix_dgram_recvmsg.
			 */
			if (UNIXCB(skb).fp)
				siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);

2064 2065
			sk_peek_offset_fwd(sk, chunk);

L
Linus Torvalds 已提交
2066 2067 2068 2069
			break;
		}
	} while (size);

I
Ingo Molnar 已提交
2070
	mutex_unlock(&u->readlock);
L
Linus Torvalds 已提交
2071 2072 2073 2074 2075 2076 2077 2078 2079 2080
	scm_recv(sock, msg, siocb->scm, flags);
out:
	return copied ? : err;
}

static int unix_shutdown(struct socket *sock, int mode)
{
	struct sock *sk = sock->sk;
	struct sock *other;

2081 2082 2083 2084 2085 2086 2087 2088
	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;
2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114

	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
2115
	}
2116 2117 2118
	if (other)
		sock_put(other);

L
Linus Torvalds 已提交
2119 2120 2121
	return 0;
}

2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133
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)
2134
			amount += unix_skb_len(skb);
2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151
	} else {
		skb = skb_peek(&sk->sk_receive_queue);
		if (skb)
			amount = skb->len;
	}
	spin_unlock(&sk->sk_receive_queue.lock);

	return amount;
}
EXPORT_SYMBOL_GPL(unix_inq_len);

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

L
Linus Torvalds 已提交
2152 2153 2154
static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	struct sock *sk = sock->sk;
2155
	long amount = 0;
L
Linus Torvalds 已提交
2156 2157
	int err;

E
Eric Dumazet 已提交
2158 2159
	switch (cmd) {
	case SIOCOUTQ:
2160
		amount = unix_outq_len(sk);
E
Eric Dumazet 已提交
2161 2162 2163
		err = put_user(amount, (int __user *)arg);
		break;
	case SIOCINQ:
2164 2165 2166 2167
		amount = unix_inq_len(sk);
		if (amount < 0)
			err = amount;
		else
L
Linus Torvalds 已提交
2168
			err = put_user(amount, (int __user *)arg);
2169
		break;
E
Eric Dumazet 已提交
2170 2171 2172
	default:
		err = -ENOIOCTLCMD;
		break;
L
Linus Torvalds 已提交
2173 2174 2175 2176
	}
	return err;
}

E
Eric Dumazet 已提交
2177
static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait)
L
Linus Torvalds 已提交
2178 2179 2180 2181
{
	struct sock *sk = sock->sk;
	unsigned int mask;

E
Eric Dumazet 已提交
2182
	sock_poll_wait(file, sk_sleep(sk), wait);
L
Linus Torvalds 已提交
2183 2184 2185 2186 2187 2188 2189
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err)
		mask |= POLLERR;
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;
2190
	if (sk->sk_shutdown & RCV_SHUTDOWN)
E
Eric Dumazet 已提交
2191
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
L
Linus Torvalds 已提交
2192 2193

	/* readable? */
E
Eric Dumazet 已提交
2194
	if (!skb_queue_empty(&sk->sk_receive_queue))
L
Linus Torvalds 已提交
2195 2196 2197
		mask |= POLLIN | POLLRDNORM;

	/* Connection-based need to check for termination and startup */
E
Eric Dumazet 已提交
2198 2199
	if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
	    sk->sk_state == TCP_CLOSE)
L
Linus Torvalds 已提交
2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211
		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;
}

2212 2213
static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
				    poll_table *wait)
2214
{
2215 2216
	struct sock *sk = sock->sk, *other;
	unsigned int mask, writable;
2217

E
Eric Dumazet 已提交
2218
	sock_poll_wait(file, sk_sleep(sk), wait);
2219 2220 2221 2222
	mask = 0;

	/* exceptional events? */
	if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
2223
		mask |= POLLERR |
2224
			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0);
2225

2226
	if (sk->sk_shutdown & RCV_SHUTDOWN)
2227
		mask |= POLLRDHUP | POLLIN | POLLRDNORM;
2228 2229 2230 2231
	if (sk->sk_shutdown == SHUTDOWN_MASK)
		mask |= POLLHUP;

	/* readable? */
2232
	if (!skb_queue_empty(&sk->sk_receive_queue))
2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243
		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
2244
	/* No write status requested, avoid expensive OUT tests. */
2245
	if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT)))
E
Eric Dumazet 已提交
2246 2247
		return mask;

2248
	writable = unix_writable(sk);
2249 2250 2251 2252 2253 2254
	other = unix_peer_get(sk);
	if (other) {
		if (unix_peer(other) != sk) {
			sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
			if (unix_recvq_full(other))
				writable = 0;
2255
		}
2256
		sock_put(other);
2257 2258 2259
	}

	if (writable)
2260 2261 2262 2263 2264 2265
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
	else
		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

	return mask;
}
L
Linus Torvalds 已提交
2266 2267

#ifdef CONFIG_PROC_FS
2268

E
Eric Dumazet 已提交
2269 2270 2271 2272 2273
#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))
2274

E
Eric Dumazet 已提交
2275
static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
L
Linus Torvalds 已提交
2276
{
E
Eric Dumazet 已提交
2277 2278 2279 2280
	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
2281

E
Eric Dumazet 已提交
2282 2283
	for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
		if (sock_net(sk) != seq_file_net(seq))
2284
			continue;
E
Eric Dumazet 已提交
2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303
		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
2304
	}
E
Eric Dumazet 已提交
2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315

	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
2316 2317 2318 2319
	return NULL;
}

static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
2320
	__acquires(unix_table_lock)
L
Linus Torvalds 已提交
2321
{
2322
	spin_lock(&unix_table_lock);
E
Eric Dumazet 已提交
2323 2324 2325 2326 2327 2328 2329 2330

	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
2331 2332 2333 2334 2335
}

static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	++*pos;
E
Eric Dumazet 已提交
2336
	return unix_next_socket(seq, v, pos);
L
Linus Torvalds 已提交
2337 2338 2339
}

static void unix_seq_stop(struct seq_file *seq, void *v)
2340
	__releases(unix_table_lock)
L
Linus Torvalds 已提交
2341
{
2342
	spin_unlock(&unix_table_lock);
L
Linus Torvalds 已提交
2343 2344 2345 2346
}

static int unix_seq_show(struct seq_file *seq, void *v)
{
2347

J
Joe Perches 已提交
2348
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
2349 2350 2351 2352 2353
		seq_puts(seq, "Num       RefCount Protocol Flags    Type St "
			 "Inode Path\n");
	else {
		struct sock *s = v;
		struct unix_sock *u = unix_sk(s);
2354
		unix_state_lock(s);
L
Linus Torvalds 已提交
2355

D
Dan Rosenberg 已提交
2356
		seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
L
Linus Torvalds 已提交
2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381
			s,
			atomic_read(&s->sk_refcnt),
			0,
			s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0,
			s->sk_type,
			s->sk_socket ?
			(s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) :
			(s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING),
			sock_i_ino(s));

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

			i = 0;
			len = u->addr->len - sizeof(short);
			if (!UNIX_ABSTRACT(s))
				len--;
			else {
				seq_putc(seq, '@');
				i++;
			}
			for ( ; i < len; i++)
				seq_putc(seq, u->addr->name->sun_path[i]);
		}
2382
		unix_state_unlock(s);
L
Linus Torvalds 已提交
2383 2384 2385 2386 2387 2388
		seq_putc(seq, '\n');
	}

	return 0;
}

2389
static const struct seq_operations unix_seq_ops = {
L
Linus Torvalds 已提交
2390 2391 2392 2393 2394 2395 2396 2397
	.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)
{
2398
	return seq_open_net(inode, file, &unix_seq_ops,
E
Eric Dumazet 已提交
2399
			    sizeof(struct seq_net_private));
L
Linus Torvalds 已提交
2400 2401
}

2402
static const struct file_operations unix_seq_fops = {
L
Linus Torvalds 已提交
2403 2404 2405 2406
	.owner		= THIS_MODULE,
	.open		= unix_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
2407
	.release	= seq_release_net,
L
Linus Torvalds 已提交
2408 2409 2410 2411
};

#endif

2412
static const struct net_proto_family unix_family_ops = {
L
Linus Torvalds 已提交
2413 2414 2415 2416 2417
	.family = PF_UNIX,
	.create = unix_create,
	.owner	= THIS_MODULE,
};

2418

2419
static int __net_init unix_net_init(struct net *net)
2420 2421 2422
{
	int error = -ENOMEM;

2423
	net->unx.sysctl_max_dgram_qlen = 10;
2424 2425
	if (unix_sysctl_register(net))
		goto out;
2426

2427
#ifdef CONFIG_PROC_FS
2428
	if (!proc_create("unix", 0, net->proc_net, &unix_seq_fops)) {
2429
		unix_sysctl_unregister(net);
2430
		goto out;
2431
	}
2432 2433 2434
#endif
	error = 0;
out:
2435
	return error;
2436 2437
}

2438
static void __net_exit unix_net_exit(struct net *net)
2439
{
2440
	unix_sysctl_unregister(net);
2441
	remove_proc_entry("unix", net->proc_net);
2442 2443 2444 2445 2446 2447 2448
}

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

L
Linus Torvalds 已提交
2449 2450 2451 2452
static int __init af_unix_init(void)
{
	int rc = -1;

2453
	BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
L
Linus Torvalds 已提交
2454 2455

	rc = proto_register(&unix_proto, 1);
2456
	if (rc != 0) {
W
wangweidong 已提交
2457
		pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
L
Linus Torvalds 已提交
2458 2459 2460 2461
		goto out;
	}

	sock_register(&unix_family_ops);
2462
	register_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2463 2464 2465 2466 2467 2468 2469 2470
out:
	return rc;
}

static void __exit af_unix_exit(void)
{
	sock_unregister(PF_UNIX);
	proto_unregister(&unix_proto);
2471
	unregister_pernet_subsys(&unix_net_ops);
L
Linus Torvalds 已提交
2472 2473
}

2474 2475 2476 2477 2478
/* 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
2479 2480 2481 2482
module_exit(af_unix_exit);

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