v4.19.13 snapshot.
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
new file mode 100644
index 0000000..c754f3a
--- /dev/null
+++ b/net/unix/af_unix.c
@@ -0,0 +1,2933 @@
+/*
+ * NET4: Implementation of BSD Unix domain sockets.
+ *
+ * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk>
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/sched/signal.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 <linux/uaccess.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#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>
+#include <linux/freezer.h>
+#include <linux/file.h>
+
+struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
+EXPORT_SYMBOL_GPL(unix_socket_table);
+DEFINE_SPINLOCK(unix_table_lock);
+EXPORT_SYMBOL_GPL(unix_table_lock);
+static atomic_long_t unix_nr_socks;
+
+
+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)
+
+#ifdef CONFIG_SECURITY_NETWORK
+static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
+{
+ UNIXCB(skb).secid = scm->secid;
+}
+
+static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
+{
+ 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);
+}
+#else
+static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
+{ }
+
+static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
+{ }
+
+static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
+{
+ return true;
+}
+#endif /* CONFIG_SECURITY_NETWORK */
+
+/*
+ * SMP locking strategy:
+ * hash table is protected with spinlock unix_table_lock
+ * each socket state is protected by separate spin lock.
+ */
+
+static inline unsigned int unix_hash_fold(__wsum n)
+{
+ unsigned int hash = (__force unsigned int)csum_fold(n);
+
+ 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)
+{
+ return unix_peer(osk) == NULL || unix_our_peer(sk, osk);
+}
+
+static inline int unix_recvq_full(struct sock const *sk)
+{
+ return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog;
+}
+
+struct sock *unix_peer_get(struct sock *s)
+{
+ struct sock *peer;
+
+ unix_state_lock(s);
+ peer = unix_peer(s);
+ if (peer)
+ sock_hold(peer);
+ unix_state_unlock(s);
+ return peer;
+}
+EXPORT_SYMBOL_GPL(unix_peer_get);
+
+static inline void unix_release_addr(struct unix_address *addr)
+{
+ if (refcount_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.
+ */
+
+static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp)
+{
+ 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.
+ * sun_path[108] doesn't as such exist. However in kernel space
+ * we are guaranteed that it is a valid memory location in our
+ * kernel address buffer.
+ */
+ ((char *)sunaddr)[len] = 0;
+ len = strlen(sunaddr->sun_path)+1+sizeof(short);
+ return len;
+ }
+
+ *hashp = unix_hash_fold(csum_partial(sunaddr, len, 0));
+ 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)
+{
+ WARN_ON(!sk_unhashed(sk));
+ sk_add_node(sk, list);
+}
+
+static inline void unix_remove_socket(struct sock *sk)
+{
+ spin_lock(&unix_table_lock);
+ __unix_remove_socket(sk);
+ spin_unlock(&unix_table_lock);
+}
+
+static inline void unix_insert_socket(struct hlist_head *list, struct sock *sk)
+{
+ spin_lock(&unix_table_lock);
+ __unix_insert_socket(list, sk);
+ spin_unlock(&unix_table_lock);
+}
+
+static struct sock *__unix_find_socket_byname(struct net *net,
+ struct sockaddr_un *sunname,
+ int len, int type, unsigned int hash)
+{
+ struct sock *s;
+
+ sk_for_each(s, &unix_socket_table[hash ^ type]) {
+ struct unix_sock *u = unix_sk(s);
+
+ if (!net_eq(sock_net(s), net))
+ continue;
+
+ if (u->addr->len == len &&
+ !memcmp(u->addr->name, sunname, len))
+ goto found;
+ }
+ s = NULL;
+found:
+ return s;
+}
+
+static inline struct sock *unix_find_socket_byname(struct net *net,
+ struct sockaddr_un *sunname,
+ int len, int type,
+ unsigned int hash)
+{
+ struct sock *s;
+
+ spin_lock(&unix_table_lock);
+ s = __unix_find_socket_byname(net, sunname, len, type, hash);
+ if (s)
+ sock_hold(s);
+ spin_unlock(&unix_table_lock);
+ return s;
+}
+
+static struct sock *unix_find_socket_byinode(struct inode *i)
+{
+ struct sock *s;
+
+ spin_lock(&unix_table_lock);
+ sk_for_each(s,
+ &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
+ struct dentry *dentry = unix_sk(s)->path.dentry;
+
+ if (dentry && d_backing_inode(dentry) == i) {
+ sock_hold(s);
+ goto found;
+ }
+ }
+ s = NULL;
+found:
+ spin_unlock(&unix_table_lock);
+ return s;
+}
+
+/* Support code for asymmetrically connected dgram sockets
+ *
+ * If a datagram socket is connected to a socket not itself connected
+ * to the first socket (eg, /dev/log), clients may only enqueue more
+ * messages if the present receive queue of the server socket is not
+ * "too large". This means there's a second writeability condition
+ * poll and sendmsg need to test. The dgram recv code will do a wake
+ * up on the peer_wait wait queue of a socket upon reception of a
+ * datagram which needs to be propagated to sleeping would-be writers
+ * since these might not have sent anything so far. This can't be
+ * accomplished via poll_wait because the lifetime of the server
+ * socket might be less than that of its clients if these break their
+ * association with it or if the server socket is closed while clients
+ * are still connected to it and there's no way to inform "a polling
+ * implementation" that it should let go of a certain wait queue
+ *
+ * In order to propagate a wake up, a wait_queue_entry_t of the client
+ * socket is enqueued on the peer_wait queue of the server socket
+ * whose wake function does a wake_up on the ordinary client socket
+ * wait queue. This connection is established whenever a write (or
+ * poll for write) hit the flow control condition and broken when the
+ * association to the server socket is dissolved or after a wake up
+ * was relayed.
+ */
+
+static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags,
+ void *key)
+{
+ struct unix_sock *u;
+ wait_queue_head_t *u_sleep;
+
+ u = container_of(q, struct unix_sock, peer_wake);
+
+ __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait,
+ q);
+ u->peer_wake.private = NULL;
+
+ /* relaying can only happen while the wq still exists */
+ u_sleep = sk_sleep(&u->sk);
+ if (u_sleep)
+ wake_up_interruptible_poll(u_sleep, key_to_poll(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),
+ EPOLLOUT |
+ EPOLLWRNORM |
+ EPOLLWRBAND);
+}
+
+/* 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 other is SOCK_DEAD, we want to make sure we signal
+ * POLLOUT, such that a subsequent write() can get a
+ * -ECONNREFUSED. Otherwise, if we haven't queued any skbs
+ * to other and its full, we will hang waiting for POLLOUT.
+ */
+ if (unix_recvq_full(other) && !sock_flag(other, SOCK_DEAD))
+ return 1;
+
+ if (connected)
+ unix_dgram_peer_wake_disconnect(sk, other);
+
+ return 0;
+}
+
+static int unix_writable(const struct sock *sk)
+{
+ return sk->sk_state != TCP_LISTEN &&
+ (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf;
+}
+
+static void unix_write_space(struct sock *sk)
+{
+ struct socket_wq *wq;
+
+ rcu_read_lock();
+ if (unix_writable(sk)) {
+ wq = rcu_dereference(sk->sk_wq);
+ if (skwq_has_sleeper(wq))
+ wake_up_interruptible_sync_poll(&wq->wait,
+ EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND);
+ sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
+ }
+ rcu_read_unlock();
+}
+
+/* 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)
+{
+ if (!skb_queue_empty(&sk->sk_receive_queue)) {
+ 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);
+
+ WARN_ON(refcount_read(&sk->sk_wmem_alloc));
+ WARN_ON(!sk_unhashed(sk));
+ WARN_ON(sk->sk_socket);
+ if (!sock_flag(sk, SOCK_DEAD)) {
+ pr_info("Attempt to release alive unix socket: %p\n", sk);
+ return;
+ }
+
+ if (u->addr)
+ unix_release_addr(u->addr);
+
+ atomic_long_dec(&unix_nr_socks);
+ local_bh_disable();
+ sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+ local_bh_enable();
+#ifdef UNIX_REFCNT_DEBUG
+ pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk,
+ atomic_long_read(&unix_nr_socks));
+#endif
+}
+
+static void unix_release_sock(struct sock *sk, int embrion)
+{
+ struct unix_sock *u = unix_sk(sk);
+ struct path path;
+ struct sock *skpair;
+ struct sk_buff *skb;
+ int state;
+
+ unix_remove_socket(sk);
+
+ /* Clear state */
+ unix_state_lock(sk);
+ sock_orphan(sk);
+ sk->sk_shutdown = SHUTDOWN_MASK;
+ path = u->path;
+ u->path.dentry = NULL;
+ u->path.mnt = NULL;
+ state = sk->sk_state;
+ sk->sk_state = TCP_CLOSE;
+ unix_state_unlock(sk);
+
+ wake_up_interruptible_all(&u->peer_wait);
+
+ skpair = unix_peer(sk);
+
+ if (skpair != NULL) {
+ if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
+ unix_state_lock(skpair);
+ /* No more writes */
+ skpair->sk_shutdown = SHUTDOWN_MASK;
+ if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
+ skpair->sk_err = ECONNRESET;
+ unix_state_unlock(skpair);
+ skpair->sk_state_change(skpair);
+ sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
+ }
+
+ unix_dgram_peer_wake_disconnect(sk, skpair);
+ 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) {
+ if (state == TCP_LISTEN)
+ unix_release_sock(skb->sk, 1);
+ /* passed fds are erased in the kfree_skb hook */
+ UNIXCB(skb).consumed = skb->len;
+ kfree_skb(skb);
+ }
+
+ if (path.dentry)
+ path_put(&path);
+
+ sock_put(sk);
+
+ /* ---- Socket is dead now and most probably destroyed ---- */
+
+ /*
+ * Fixme: BSD difference: In BSD all sockets connected to us get
+ * 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)
+ */
+
+ if (unix_tot_inflight)
+ unix_gc(); /* Garbage collect fds */
+}
+
+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);
+}
+
+static int unix_listen(struct socket *sock, int backlog)
+{
+ int err;
+ struct sock *sk = sock->sk;
+ struct unix_sock *u = unix_sk(sk);
+ struct pid *old_pid = NULL;
+
+ err = -EOPNOTSUPP;
+ if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
+ goto out; /* Only stream/seqpacket sockets accept */
+ err = -EINVAL;
+ if (!u->addr)
+ goto out; /* No listens on an unbound socket */
+ unix_state_lock(sk);
+ 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 */
+ init_peercred(sk);
+ err = 0;
+
+out_unlock:
+ unix_state_unlock(sk);
+ put_pid(old_pid);
+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, bool);
+static int unix_getname(struct socket *, struct sockaddr *, int);
+static __poll_t unix_poll(struct file *, struct socket *, poll_table *);
+static __poll_t unix_dgram_poll(struct file *, struct socket *,
+ poll_table *);
+static int unix_ioctl(struct socket *, unsigned int, unsigned long);
+static int unix_shutdown(struct socket *, int);
+static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t);
+static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int);
+static ssize_t unix_stream_sendpage(struct socket *, struct page *, int offset,
+ size_t size, int flags);
+static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos,
+ struct pipe_inode_info *, size_t size,
+ unsigned int flags);
+static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
+static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
+static int unix_dgram_connect(struct socket *, struct sockaddr *,
+ int, int);
+static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
+static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t,
+ int);
+
+static int unix_set_peek_off(struct sock *sk, int val)
+{
+ struct unix_sock *u = unix_sk(sk);
+
+ if (mutex_lock_interruptible(&u->iolock))
+ return -EINTR;
+
+ sk->sk_peek_off = val;
+ mutex_unlock(&u->iolock);
+
+ return 0;
+}
+
+
+static const struct proto_ops unix_stream_ops = {
+ .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 = unix_stream_sendpage,
+ .splice_read = unix_stream_splice_read,
+ .set_peek_off = unix_set_peek_off,
+};
+
+static const struct proto_ops unix_dgram_ops = {
+ .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,
+ .poll = unix_dgram_poll,
+ .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,
+ .set_peek_off = unix_set_peek_off,
+};
+
+static const struct proto_ops unix_seqpacket_ops = {
+ .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_dgram_poll,
+ .ioctl = unix_ioctl,
+ .listen = unix_listen,
+ .shutdown = unix_shutdown,
+ .setsockopt = sock_no_setsockopt,
+ .getsockopt = sock_no_getsockopt,
+ .sendmsg = unix_seqpacket_sendmsg,
+ .recvmsg = unix_seqpacket_recvmsg,
+ .mmap = sock_no_mmap,
+ .sendpage = sock_no_sendpage,
+ .set_peek_off = unix_set_peek_off,
+};
+
+static struct proto unix_proto = {
+ .name = "UNIX",
+ .owner = THIS_MODULE,
+ .obj_size = sizeof(struct unix_sock),
+};
+
+static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
+{
+ struct sock *sk = NULL;
+ struct unix_sock *u;
+
+ atomic_long_inc(&unix_nr_socks);
+ if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
+ goto out;
+
+ sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto, kern);
+ if (!sk)
+ goto out;
+
+ sock_init_data(sock, sk);
+
+ sk->sk_allocation = GFP_KERNEL_ACCOUNT;
+ sk->sk_write_space = unix_write_space;
+ sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
+ sk->sk_destruct = unix_sock_destructor;
+ u = unix_sk(sk);
+ u->path.dentry = NULL;
+ u->path.mnt = NULL;
+ spin_lock_init(&u->lock);
+ atomic_long_set(&u->inflight, 0);
+ INIT_LIST_HEAD(&u->link);
+ mutex_init(&u->iolock); /* single task reading lock */
+ mutex_init(&u->bindlock); /* single task binding lock */
+ init_waitqueue_head(&u->peer_wait);
+ init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
+ unix_insert_socket(unix_sockets_unbound(sk), sk);
+out:
+ if (sk == NULL)
+ atomic_long_dec(&unix_nr_socks);
+ else {
+ local_bh_disable();
+ sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+ local_bh_enable();
+ }
+ return sk;
+}
+
+static int unix_create(struct net *net, struct socket *sock, int protocol,
+ int kern)
+{
+ 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:
+ sock->type = SOCK_DGRAM;
+ /* fall through */
+ case SOCK_DGRAM:
+ sock->ops = &unix_dgram_ops;
+ break;
+ case SOCK_SEQPACKET:
+ sock->ops = &unix_seqpacket_ops;
+ break;
+ default:
+ return -ESOCKTNOSUPPORT;
+ }
+
+ return unix_create1(net, sock, kern) ? 0 : -ENOMEM;
+}
+
+static int unix_release(struct socket *sock)
+{
+ struct sock *sk = sock->sk;
+
+ if (!sk)
+ return 0;
+
+ unix_release_sock(sk, 0);
+ sock->sk = NULL;
+
+ return 0;
+}
+
+static int unix_autobind(struct socket *sock)
+{
+ struct sock *sk = sock->sk;
+ struct net *net = sock_net(sk);
+ struct unix_sock *u = unix_sk(sk);
+ static u32 ordernum = 1;
+ struct unix_address *addr;
+ int err;
+ unsigned int retries = 0;
+
+ err = mutex_lock_interruptible(&u->bindlock);
+ if (err)
+ return err;
+
+ err = 0;
+ if (u->addr)
+ goto out;
+
+ err = -ENOMEM;
+ addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);
+ if (!addr)
+ goto out;
+
+ addr->name->sun_family = AF_UNIX;
+ refcount_set(&addr->refcnt, 1);
+
+retry:
+ addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
+ addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));
+
+ spin_lock(&unix_table_lock);
+ ordernum = (ordernum+1)&0xFFFFF;
+
+ if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
+ addr->hash)) {
+ spin_unlock(&unix_table_lock);
+ /*
+ * __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;
+ }
+ goto retry;
+ }
+ addr->hash ^= sk->sk_type;
+
+ __unix_remove_socket(sk);
+ u->addr = addr;
+ __unix_insert_socket(&unix_socket_table[addr->hash], sk);
+ spin_unlock(&unix_table_lock);
+ err = 0;
+
+out: mutex_unlock(&u->bindlock);
+ return err;
+}
+
+static struct sock *unix_find_other(struct net *net,
+ struct sockaddr_un *sunname, int len,
+ int type, unsigned int hash, int *error)
+{
+ struct sock *u;
+ struct path path;
+ int err = 0;
+
+ if (sunname->sun_path[0]) {
+ struct inode *inode;
+ err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path);
+ if (err)
+ goto fail;
+ inode = d_backing_inode(path.dentry);
+ err = inode_permission(inode, MAY_WRITE);
+ if (err)
+ goto put_fail;
+
+ err = -ECONNREFUSED;
+ if (!S_ISSOCK(inode->i_mode))
+ goto put_fail;
+ u = unix_find_socket_byinode(inode);
+ if (!u)
+ goto put_fail;
+
+ if (u->sk_type == type)
+ touch_atime(&path);
+
+ path_put(&path);
+
+ err = -EPROTOTYPE;
+ if (u->sk_type != type) {
+ sock_put(u);
+ goto fail;
+ }
+ } else {
+ err = -ECONNREFUSED;
+ u = unix_find_socket_byname(net, sunname, len, type, hash);
+ if (u) {
+ struct dentry *dentry;
+ dentry = unix_sk(u)->path.dentry;
+ if (dentry)
+ touch_atime(&unix_sk(u)->path);
+ } else
+ goto fail;
+ }
+ return u;
+
+put_fail:
+ path_put(&path);
+fail:
+ *error = err;
+ return NULL;
+}
+
+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(d_inode(path.dentry), dentry, mode, 0);
+ if (!err) {
+ res->mnt = mntget(path.mnt);
+ res->dentry = dget(dentry);
+ }
+ }
+ done_path_create(&path, dentry);
+ return err;
+}
+
+static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
+{
+ struct sock *sk = sock->sk;
+ struct net *net = sock_net(sk);
+ struct unix_sock *u = unix_sk(sk);
+ struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
+ char *sun_path = sunaddr->sun_path;
+ int err;
+ unsigned int hash;
+ struct unix_address *addr;
+ struct hlist_head *list;
+ struct path path = { };
+
+ err = -EINVAL;
+ if (addr_len < offsetofend(struct sockaddr_un, sun_family) ||
+ sunaddr->sun_family != AF_UNIX)
+ goto out;
+
+ if (addr_len == sizeof(short)) {
+ err = unix_autobind(sock);
+ goto out;
+ }
+
+ err = unix_mkname(sunaddr, addr_len, &hash);
+ if (err < 0)
+ goto out;
+ addr_len = err;
+
+ 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;
+ }
+ }
+
+ err = mutex_lock_interruptible(&u->bindlock);
+ if (err)
+ goto out_put;
+
+ 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;
+ refcount_set(&addr->refcnt, 1);
+
+ if (sun_path[0]) {
+ addr->hash = UNIX_HASH_SIZE;
+ hash = d_backing_inode(path.dentry)->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);
+ err = -EADDRINUSE;
+ if (__unix_find_socket_byname(net, sunaddr, addr_len,
+ 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:
+ spin_unlock(&unix_table_lock);
+out_up:
+ mutex_unlock(&u->bindlock);
+out_put:
+ if (err)
+ path_put(&path);
+out:
+ return err;
+}
+
+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);
+}
+
+static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
+ int alen, int flags)
+{
+ struct sock *sk = sock->sk;
+ struct net *net = sock_net(sk);
+ struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr;
+ struct sock *other;
+ unsigned int hash;
+ int err;
+
+ err = -EINVAL;
+ if (alen < offsetofend(struct sockaddr, sa_family))
+ goto out;
+
+ 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;
+
+restart:
+ other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
+ if (!other)
+ goto out;
+
+ 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;
+ }
+
+ 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;
+ unix_state_double_lock(sk, other);
+ }
+
+ /*
+ * If it was connected, reconnect.
+ */
+ if (unix_peer(sk)) {
+ struct sock *old_peer = unix_peer(sk);
+ unix_peer(sk) = other;
+ unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer);
+
+ unix_state_double_unlock(sk, other);
+
+ if (other != old_peer)
+ unix_dgram_disconnected(sk, old_peer);
+ sock_put(old_peer);
+ } else {
+ unix_peer(sk) = other;
+ unix_state_double_unlock(sk, other);
+ }
+ return 0;
+
+out_unlock:
+ unix_state_double_unlock(sk, other);
+ 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) &&
+ unix_recvq_full(other);
+
+ unix_state_unlock(other);
+
+ 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)
+{
+ struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
+ struct sock *sk = sock->sk;
+ struct net *net = sock_net(sk);
+ struct unix_sock *u = unix_sk(sk), *newu, *otheru;
+ struct sock *newsk = NULL;
+ struct sock *other = NULL;
+ struct sk_buff *skb = NULL;
+ unsigned int hash;
+ int st;
+ int err;
+ long timeo;
+
+ err = unix_mkname(sunaddr, addr_len, &hash);
+ if (err < 0)
+ goto out;
+ addr_len = err;
+
+ if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
+ (err = unix_autobind(sock)) != 0)
+ 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 */
+ newsk = unix_create1(sock_net(sk), NULL, 0);
+ 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. */
+ other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err);
+ if (!other)
+ goto out;
+
+ /* Latch state of peer */
+ unix_state_lock(other);
+
+ /* Apparently VFS overslept socket death. Retry. */
+ if (sock_flag(other, SOCK_DEAD)) {
+ unix_state_unlock(other);
+ sock_put(other);
+ goto restart;
+ }
+
+ err = -ECONNREFUSED;
+ if (other->sk_state != TCP_LISTEN)
+ goto out_unlock;
+ if (other->sk_shutdown & RCV_SHUTDOWN)
+ goto out_unlock;
+
+ if (unix_recvq_full(other)) {
+ 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;
+ }
+
+ /* Latch our state.
+
+ It is tricky place. We need to grab our state lock and cannot
+ 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;
+ }
+
+ unix_state_lock_nested(sk);
+
+ if (sk->sk_state != st) {
+ unix_state_unlock(sk);
+ unix_state_unlock(other);
+ sock_put(other);
+ goto restart;
+ }
+
+ err = security_unix_stream_connect(sk, other, newsk);
+ if (err) {
+ unix_state_unlock(sk);
+ 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;
+ init_peercred(newsk);
+ newu = unix_sk(newsk);
+ RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq);
+ otheru = unix_sk(other);
+
+ /* copy address information from listening to new sock*/
+ if (otheru->addr) {
+ refcount_inc(&otheru->addr->refcnt);
+ newu->addr = otheru->addr;
+ }
+ if (otheru->path.dentry) {
+ path_get(&otheru->path);
+ newu->path = otheru->path;
+ }
+
+ /* Set credentials */
+ copy_peercred(sk, other);
+
+ sock->state = SS_CONNECTED;
+ sk->sk_state = TCP_ESTABLISHED;
+ sock_hold(newsk);
+
+ smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */
+ unix_peer(sk) = newsk;
+
+ unix_state_unlock(sk);
+
+ /* 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);
+ unix_state_unlock(other);
+ other->sk_data_ready(other);
+ sock_put(other);
+ return 0;
+
+out_unlock:
+ if (other)
+ unix_state_unlock(other);
+
+out:
+ kfree_skb(skb);
+ if (newsk)
+ unix_release_sock(newsk, 0);
+ if (other)
+ sock_put(other);
+ return err;
+}
+
+static int unix_socketpair(struct socket *socka, struct socket *sockb)
+{
+ struct sock *ska = socka->sk, *skb = sockb->sk;
+
+ /* Join our sockets back to back */
+ sock_hold(ska);
+ sock_hold(skb);
+ unix_peer(ska) = skb;
+ unix_peer(skb) = ska;
+ init_peercred(ska);
+ init_peercred(skb);
+
+ 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;
+}
+
+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);
+}
+
+static int unix_accept(struct socket *sock, struct socket *newsock, int flags,
+ bool kern)
+{
+ struct sock *sk = sock->sk;
+ struct sock *tsk;
+ struct sk_buff *skb;
+ int err;
+
+ err = -EOPNOTSUPP;
+ if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
+ 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 */
+ unix_state_lock(tsk);
+ newsock->state = SS_CONNECTED;
+ unix_sock_inherit_flags(sock, newsock);
+ sock_graft(tsk, newsock);
+ unix_state_unlock(tsk);
+ return 0;
+
+out:
+ return err;
+}
+
+
+static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
+{
+ struct sock *sk = sock->sk;
+ struct unix_sock *u;
+ DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
+ 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);
+ unix_state_lock(sk);
+ if (!u->addr) {
+ sunaddr->sun_family = AF_UNIX;
+ sunaddr->sun_path[0] = 0;
+ err = sizeof(short);
+ } else {
+ struct unix_address *addr = u->addr;
+
+ err = addr->len;
+ memcpy(sunaddr, addr->name, addr->len);
+ }
+ unix_state_unlock(sk);
+ 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;
+
+ for (i = scm->fp->count-1; i >= 0; i--)
+ unix_notinflight(scm->fp->user, scm->fp->fp[i]);
+}
+
+static void unix_destruct_scm(struct sk_buff *skb)
+{
+ struct scm_cookie scm;
+ memset(&scm, 0, sizeof(scm));
+ scm.pid = UNIXCB(skb).pid;
+ if (UNIXCB(skb).fp)
+ unix_detach_fds(&scm, skb);
+
+ /* Alas, it calls VFS */
+ /* So fscking what? fput() had been SMP-safe since the last Summer */
+ scm_destroy(&scm);
+ sock_wfree(skb);
+}
+
+/*
+ * 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;
+}
+
+static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
+{
+ int i;
+
+ if (too_many_unix_fds(current))
+ return -ETOOMANYREFS;
+
+ /*
+ * 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;
+
+ for (i = scm->fp->count - 1; i >= 0; i--)
+ unix_inflight(scm->fp->user, scm->fp->fp[i]);
+ return 0;
+}
+
+static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
+{
+ int err = 0;
+
+ UNIXCB(skb).pid = get_pid(scm->pid);
+ UNIXCB(skb).uid = scm->creds.uid;
+ UNIXCB(skb).gid = scm->creds.gid;
+ UNIXCB(skb).fp = NULL;
+ unix_get_secdata(scm, skb);
+ if (scm->fp && send_fds)
+ err = unix_attach_fds(scm, skb);
+
+ skb->destructor = unix_destruct_scm;
+ return err;
+}
+
+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);
+}
+
+/*
+ * 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)
+{
+ if (UNIXCB(skb).pid)
+ return;
+ if (unix_passcred_enabled(sock, other)) {
+ UNIXCB(skb).pid = get_pid(task_tgid(current));
+ current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);
+ }
+}
+
+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);
+}
+
+/*
+ * Send AF_UNIX data.
+ */
+
+static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
+ size_t len)
+{
+ struct sock *sk = sock->sk;
+ struct net *net = sock_net(sk);
+ struct unix_sock *u = unix_sk(sk);
+ DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);
+ struct sock *other = NULL;
+ int namelen = 0; /* fake GCC */
+ int err;
+ unsigned int hash;
+ struct sk_buff *skb;
+ long timeo;
+ struct scm_cookie scm;
+ int data_len = 0;
+ int sk_locked;
+
+ wait_for_unix_gc();
+ err = scm_send(sock, msg, &scm, false);
+ 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;
+ }
+
+ if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
+ && (err = unix_autobind(sock)) != 0)
+ goto out;
+
+ err = -EMSGSIZE;
+ if (len > sk->sk_sndbuf - 32)
+ goto out;
+
+ if (len > SKB_MAX_ALLOC) {
+ data_len = min_t(size_t,
+ len - SKB_MAX_ALLOC,
+ MAX_SKB_FRAGS * PAGE_SIZE);
+ data_len = PAGE_ALIGN(data_len);
+
+ BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE);
+ }
+
+ skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
+ msg->msg_flags & MSG_DONTWAIT, &err,
+ PAGE_ALLOC_COSTLY_ORDER);
+ if (skb == NULL)
+ goto out;
+
+ err = unix_scm_to_skb(&scm, skb, true);
+ if (err < 0)
+ goto out_free;
+
+ skb_put(skb, len - data_len);
+ skb->data_len = data_len;
+ skb->len = len;
+ err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
+ 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;
+
+ other = unix_find_other(net, sunaddr, namelen, sk->sk_type,
+ hash, &err);
+ if (other == NULL)
+ goto out_free;
+ }
+
+ if (sk_filter(other, skb) < 0) {
+ /* Toss the packet but do not return any error to the sender */
+ err = len;
+ goto out_free;
+ }
+
+ sk_locked = 0;
+ unix_state_lock(other);
+restart_locked:
+ err = -EPERM;
+ if (!unix_may_send(sk, other))
+ goto out_unlock;
+
+ if (unlikely(sock_flag(other, SOCK_DEAD))) {
+ /*
+ * Check with 1003.1g - what should
+ * datagram error
+ */
+ unix_state_unlock(other);
+ sock_put(other);
+
+ if (!sk_locked)
+ unix_state_lock(sk);
+
+ err = 0;
+ if (unix_peer(sk) == other) {
+ unix_peer(sk) = NULL;
+ unix_dgram_peer_wake_disconnect_wakeup(sk, other);
+
+ unix_state_unlock(sk);
+
+ unix_dgram_disconnected(sk, other);
+ sock_put(other);
+ err = -ECONNREFUSED;
+ } else {
+ unix_state_unlock(sk);
+ }
+
+ 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;
+ }
+
+ /* 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))) {
+ if (timeo) {
+ timeo = unix_wait_for_peer(other, timeo);
+
+ err = sock_intr_errno(timeo);
+ if (signal_pending(current))
+ goto out_free;
+
+ goto restart;
+ }
+
+ if (!sk_locked) {
+ unix_state_unlock(other);
+ unix_state_double_lock(sk, other);
+ }
+
+ if (unix_peer(sk) != other ||
+ unix_dgram_peer_wake_me(sk, other)) {
+ err = -EAGAIN;
+ sk_locked = 1;
+ goto out_unlock;
+ }
+
+ if (!sk_locked) {
+ sk_locked = 1;
+ goto restart_locked;
+ }
+ }
+
+ if (unlikely(sk_locked))
+ unix_state_unlock(sk);
+
+ if (sock_flag(other, SOCK_RCVTSTAMP))
+ __net_timestamp(skb);
+ maybe_add_creds(skb, sock, other);
+ skb_queue_tail(&other->sk_receive_queue, skb);
+ unix_state_unlock(other);
+ other->sk_data_ready(other);
+ sock_put(other);
+ scm_destroy(&scm);
+ return len;
+
+out_unlock:
+ if (sk_locked)
+ unix_state_unlock(sk);
+ unix_state_unlock(other);
+out_free:
+ kfree_skb(skb);
+out:
+ if (other)
+ sock_put(other);
+ scm_destroy(&scm);
+ return err;
+}
+
+/* We use paged skbs for stream sockets, and limit occupancy to 32768
+ * bytes, and a minimum of a full page.
+ */
+#define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768))
+
+static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
+ size_t len)
+{
+ struct sock *sk = sock->sk;
+ struct sock *other = NULL;
+ int err, size;
+ struct sk_buff *skb;
+ int sent = 0;
+ struct scm_cookie scm;
+ bool fds_sent = false;
+ int data_len;
+
+ wait_for_unix_gc();
+ err = scm_send(sock, msg, &scm, false);
+ 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;
+ other = unix_peer(sk);
+ if (!other)
+ goto out_err;
+ }
+
+ if (sk->sk_shutdown & SEND_SHUTDOWN)
+ goto pipe_err;
+
+ while (sent < len) {
+ size = len - sent;
+
+ /* Keep two messages in the pipe so it schedules better */
+ size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
+
+ /* allow fallback to order-0 allocations */
+ size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ);
+
+ data_len = max_t(int, 0, size - SKB_MAX_HEAD(0));
+
+ data_len = min_t(size_t, size, PAGE_ALIGN(data_len));
+
+ skb = sock_alloc_send_pskb(sk, size - data_len, data_len,
+ msg->msg_flags & MSG_DONTWAIT, &err,
+ get_order(UNIX_SKB_FRAGS_SZ));
+ if (!skb)
+ goto out_err;
+
+ /* Only send the fds in the first buffer */
+ err = unix_scm_to_skb(&scm, skb, !fds_sent);
+ if (err < 0) {
+ kfree_skb(skb);
+ goto out_err;
+ }
+ fds_sent = true;
+
+ skb_put(skb, size - data_len);
+ skb->data_len = data_len;
+ skb->len = size;
+ err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
+ if (err) {
+ kfree_skb(skb);
+ goto out_err;
+ }
+
+ unix_state_lock(other);
+
+ if (sock_flag(other, SOCK_DEAD) ||
+ (other->sk_shutdown & RCV_SHUTDOWN))
+ goto pipe_err_free;
+
+ maybe_add_creds(skb, sock, other);
+ skb_queue_tail(&other->sk_receive_queue, skb);
+ unix_state_unlock(other);
+ other->sk_data_ready(other);
+ sent += size;
+ }
+
+ scm_destroy(&scm);
+
+ return sent;
+
+pipe_err_free:
+ unix_state_unlock(other);
+ kfree_skb(skb);
+pipe_err:
+ if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
+ send_sig(SIGPIPE, current, 0);
+ err = -EPIPE;
+out_err:
+ scm_destroy(&scm);
+ return sent ? : err;
+}
+
+static ssize_t unix_stream_sendpage(struct socket *socket, struct page *page,
+ int offset, size_t size, int flags)
+{
+ int err;
+ bool send_sigpipe = false;
+ bool init_scm = true;
+ struct scm_cookie scm;
+ 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);
+ mutex_unlock(&unix_sk(other)->iolock);
+ newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
+ &err, 0);
+ if (!newskb)
+ goto err;
+ }
+
+ /* we must acquire iolock as we modify already present
+ * skbs in the sk_receive_queue and mess with skb->len
+ */
+ err = mutex_lock_interruptible(&unix_sk(other)->iolock);
+ if (err) {
+ err = flags & MSG_DONTWAIT ? -EAGAIN : -ERESTARTSYS;
+ goto err;
+ }
+
+ if (sk->sk_shutdown & SEND_SHUTDOWN) {
+ err = -EPIPE;
+ send_sigpipe = true;
+ goto err_unlock;
+ }
+
+ unix_state_lock(other);
+
+ if (sock_flag(other, SOCK_DEAD) ||
+ other->sk_shutdown & RCV_SHUTDOWN) {
+ err = -EPIPE;
+ send_sigpipe = true;
+ goto err_state_unlock;
+ }
+
+ if (init_scm) {
+ err = maybe_init_creds(&scm, socket, other);
+ if (err)
+ goto err_state_unlock;
+ init_scm = false;
+ }
+
+ skb = skb_peek_tail(&other->sk_receive_queue);
+ if (tail && tail == skb) {
+ skb = newskb;
+ } else if (!skb || !unix_skb_scm_eq(skb, &scm)) {
+ if (newskb) {
+ skb = newskb;
+ } else {
+ tail = skb;
+ goto alloc_skb;
+ }
+ } 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);
+ newskb = NULL;
+ }
+
+ if (skb_append_pagefrags(skb, page, offset, size)) {
+ tail = skb;
+ goto alloc_skb;
+ }
+
+ skb->len += size;
+ skb->data_len += size;
+ skb->truesize += size;
+ refcount_add(size, &sk->sk_wmem_alloc);
+
+ if (newskb) {
+ err = unix_scm_to_skb(&scm, skb, false);
+ if (err)
+ goto err_state_unlock;
+ spin_lock(&other->sk_receive_queue.lock);
+ __skb_queue_tail(&other->sk_receive_queue, newskb);
+ spin_unlock(&other->sk_receive_queue.lock);
+ }
+
+ unix_state_unlock(other);
+ mutex_unlock(&unix_sk(other)->iolock);
+
+ other->sk_data_ready(other);
+ scm_destroy(&scm);
+ return size;
+
+err_state_unlock:
+ unix_state_unlock(other);
+err_unlock:
+ mutex_unlock(&unix_sk(other)->iolock);
+err:
+ kfree_skb(newskb);
+ if (send_sigpipe && !(flags & MSG_NOSIGNAL))
+ send_sig(SIGPIPE, current, 0);
+ if (!init_scm)
+ scm_destroy(&scm);
+ return err;
+}
+
+static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg,
+ size_t len)
+{
+ int err;
+ struct sock *sk = sock->sk;
+
+ 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(sock, msg, len);
+}
+
+static int unix_seqpacket_recvmsg(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(sock, msg, size, flags);
+}
+
+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 socket *sock, struct msghdr *msg,
+ size_t size, int flags)
+{
+ struct scm_cookie scm;
+ struct sock *sk = sock->sk;
+ struct unix_sock *u = unix_sk(sk);
+ struct sk_buff *skb, *last;
+ long timeo;
+ int err;
+ int peeked, skip;
+
+ err = -EOPNOTSUPP;
+ if (flags&MSG_OOB)
+ goto out;
+
+ timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+
+ do {
+ mutex_lock(&u->iolock);
+
+ skip = sk_peek_offset(sk, flags);
+ skb = __skb_try_recv_datagram(sk, flags, NULL, &peeked, &skip,
+ &err, &last);
+ if (skb)
+ break;
+
+ mutex_unlock(&u->iolock);
+
+ if (err != -EAGAIN)
+ break;
+ } while (timeo &&
+ !__skb_wait_for_more_packets(sk, &err, &timeo, last));
+
+ if (!skb) { /* implies iolock unlocked */
+ 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);
+ goto out;
+ }
+
+ if (wq_has_sleeper(&u->peer_wait))
+ wake_up_interruptible_sync_poll(&u->peer_wait,
+ EPOLLOUT | EPOLLWRNORM |
+ EPOLLWRBAND);
+
+ if (msg->msg_name)
+ unix_copy_addr(msg, skb->sk);
+
+ if (size > skb->len - skip)
+ size = skb->len - skip;
+ else if (size < skb->len - skip)
+ msg->msg_flags |= MSG_TRUNC;
+
+ err = skb_copy_datagram_msg(skb, skip, msg, size);
+ if (err)
+ goto out_free;
+
+ if (sock_flag(sk, SOCK_RCVTSTAMP))
+ __sock_recv_timestamp(msg, sk, skb);
+
+ memset(&scm, 0, sizeof(scm));
+
+ scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
+ unix_set_secdata(&scm, skb);
+
+ if (!(flags & MSG_PEEK)) {
+ if (UNIXCB(skb).fp)
+ unix_detach_fds(&scm, skb);
+
+ sk_peek_offset_bwd(sk, skb->len);
+ } else {
+ /* 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)
+
+ POSIX 1003.1g does not actually define this clearly
+ at all. POSIX 1003.1g doesn't define a lot of things
+ clearly however!
+
+ */
+
+ sk_peek_offset_fwd(sk, size);
+
+ if (UNIXCB(skb).fp)
+ scm.fp = scm_fp_dup(UNIXCB(skb).fp);
+ }
+ err = (flags & MSG_TRUNC) ? skb->len - skip : size;
+
+ scm_recv(sock, msg, &scm, flags);
+
+out_free:
+ skb_free_datagram(sk, skb);
+ mutex_unlock(&u->iolock);
+out:
+ return err;
+}
+
+/*
+ * Sleep until more data has arrived. But check for races..
+ */
+static long unix_stream_data_wait(struct sock *sk, long timeo,
+ struct sk_buff *last, unsigned int last_len,
+ bool freezable)
+{
+ struct sk_buff *tail;
+ DEFINE_WAIT(wait);
+
+ unix_state_lock(sk);
+
+ for (;;) {
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+
+ tail = skb_peek_tail(&sk->sk_receive_queue);
+ if (tail != last ||
+ (tail && tail->len != last_len) ||
+ sk->sk_err ||
+ (sk->sk_shutdown & RCV_SHUTDOWN) ||
+ signal_pending(current) ||
+ !timeo)
+ break;
+
+ sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+ unix_state_unlock(sk);
+ if (freezable)
+ timeo = freezable_schedule_timeout(timeo);
+ else
+ timeo = schedule_timeout(timeo);
+ unix_state_lock(sk);
+
+ if (sock_flag(sk, SOCK_DEAD))
+ break;
+
+ sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+ }
+
+ finish_wait(sk_sleep(sk), &wait);
+ unix_state_unlock(sk);
+ return timeo;
+}
+
+static unsigned int unix_skb_len(const struct sk_buff *skb)
+{
+ return skb->len - UNIXCB(skb).consumed;
+}
+
+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;
+};
+
+static int unix_stream_read_generic(struct unix_stream_read_state *state,
+ bool freezable)
+{
+ struct scm_cookie scm;
+ struct socket *sock = state->socket;
+ struct sock *sk = sock->sk;
+ struct unix_sock *u = unix_sk(sk);
+ int copied = 0;
+ int flags = state->flags;
+ int noblock = flags & MSG_DONTWAIT;
+ bool check_creds = false;
+ int target;
+ int err = 0;
+ long timeo;
+ int skip;
+ size_t size = state->size;
+ unsigned int last_len;
+
+ if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ if (unlikely(flags & MSG_OOB)) {
+ err = -EOPNOTSUPP;
+ goto out;
+ }
+
+ target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
+ timeo = sock_rcvtimeo(sk, noblock);
+
+ memset(&scm, 0, sizeof(scm));
+
+ /* Lock the socket to prevent queue disordering
+ * while sleeps in memcpy_tomsg
+ */
+ mutex_lock(&u->iolock);
+
+ skip = max(sk_peek_offset(sk, flags), 0);
+
+ do {
+ int chunk;
+ bool drop_skb;
+ struct sk_buff *skb, *last;
+
+redo:
+ unix_state_lock(sk);
+ if (sock_flag(sk, SOCK_DEAD)) {
+ err = -ECONNRESET;
+ goto unlock;
+ }
+ last = skb = skb_peek(&sk->sk_receive_queue);
+ last_len = last ? last->len : 0;
+again:
+ if (skb == NULL) {
+ if (copied >= target)
+ goto unlock;
+
+ /*
+ * POSIX 1003.1g mandates this order.
+ */
+
+ err = sock_error(sk);
+ if (err)
+ goto unlock;
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ goto unlock;
+
+ unix_state_unlock(sk);
+ if (!timeo) {
+ err = -EAGAIN;
+ break;
+ }
+
+ mutex_unlock(&u->iolock);
+
+ timeo = unix_stream_data_wait(sk, timeo, last,
+ last_len, freezable);
+
+ if (signal_pending(current)) {
+ err = sock_intr_errno(timeo);
+ scm_destroy(&scm);
+ goto out;
+ }
+
+ mutex_lock(&u->iolock);
+ goto redo;
+unlock:
+ unix_state_unlock(sk);
+ break;
+ }
+
+ while (skip >= unix_skb_len(skb)) {
+ skip -= unix_skb_len(skb);
+ last = skb;
+ last_len = skb->len;
+ skb = skb_peek_next(skb, &sk->sk_receive_queue);
+ if (!skb)
+ goto again;
+ }
+
+ unix_state_unlock(sk);
+
+ if (check_creds) {
+ /* Never glue messages from different writers */
+ if (!unix_skb_scm_eq(skb, &scm))
+ break;
+ } else if (test_bit(SOCK_PASSCRED, &sock->flags)) {
+ /* Copy credentials */
+ scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid);
+ unix_set_secdata(&scm, skb);
+ check_creds = true;
+ }
+
+ /* Copy address just once */
+ if (state->msg && state->msg->msg_name) {
+ DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,
+ state->msg->msg_name);
+ unix_copy_addr(state->msg, skb->sk);
+ sunaddr = NULL;
+ }
+
+ chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size);
+ skb_get(skb);
+ chunk = state->recv_actor(skb, skip, chunk, state);
+ drop_skb = !unix_skb_len(skb);
+ /* skb is only safe to use if !drop_skb */
+ consume_skb(skb);
+ if (chunk < 0) {
+ if (copied == 0)
+ copied = -EFAULT;
+ break;
+ }
+ copied += chunk;
+ size -= chunk;
+
+ 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;
+ }
+
+ /* Mark read part of skb as used */
+ if (!(flags & MSG_PEEK)) {
+ UNIXCB(skb).consumed += chunk;
+
+ sk_peek_offset_bwd(sk, chunk);
+
+ if (UNIXCB(skb).fp)
+ unix_detach_fds(&scm, skb);
+
+ if (unix_skb_len(skb))
+ break;
+
+ skb_unlink(skb, &sk->sk_receive_queue);
+ consume_skb(skb);
+
+ if (scm.fp)
+ break;
+ } else {
+ /* It is questionable, see note in unix_dgram_recvmsg.
+ */
+ if (UNIXCB(skb).fp)
+ scm.fp = scm_fp_dup(UNIXCB(skb).fp);
+
+ sk_peek_offset_fwd(sk, chunk);
+
+ if (UNIXCB(skb).fp)
+ break;
+
+ skip = 0;
+ 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);
+ break;
+ }
+ } while (size);
+
+ mutex_unlock(&u->iolock);
+ if (state->msg)
+ scm_recv(sock, state->msg, &scm, flags);
+ else
+ scm_destroy(&scm);
+out:
+ return copied ? : err;
+}
+
+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
+ };
+
+ return unix_stream_read_generic(&state, true);
+}
+
+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,
+ state->pipe, chunk, state->splice_flags);
+}
+
+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;
+
+ return unix_stream_read_generic(&state, false);
+}
+
+static int unix_shutdown(struct socket *sock, int mode)
+{
+ struct sock *sk = sock->sk;
+ struct sock *other;
+
+ 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;
+
+ 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);
+ }
+ if (other)
+ sock_put(other);
+
+ return 0;
+}
+
+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)
+ amount += unix_skb_len(skb);
+ } 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);
+
+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;
+}
+
+static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+ struct sock *sk = sock->sk;
+ long amount = 0;
+ int err;
+
+ switch (cmd) {
+ case SIOCOUTQ:
+ amount = unix_outq_len(sk);
+ err = put_user(amount, (int __user *)arg);
+ break;
+ case SIOCINQ:
+ amount = unix_inq_len(sk);
+ if (amount < 0)
+ err = amount;
+ else
+ err = put_user(amount, (int __user *)arg);
+ break;
+ case SIOCUNIXFILE:
+ err = unix_open_file(sk);
+ break;
+ default:
+ err = -ENOIOCTLCMD;
+ break;
+ }
+ return err;
+}
+
+static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait)
+{
+ struct sock *sk = sock->sk;
+ __poll_t mask;
+
+ sock_poll_wait(file, sock, wait);
+ mask = 0;
+
+ /* exceptional events? */
+ if (sk->sk_err)
+ mask |= EPOLLERR;
+ if (sk->sk_shutdown == SHUTDOWN_MASK)
+ mask |= EPOLLHUP;
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
+
+ /* readable? */
+ if (!skb_queue_empty(&sk->sk_receive_queue))
+ mask |= EPOLLIN | EPOLLRDNORM;
+
+ /* Connection-based need to check for termination and startup */
+ if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) &&
+ sk->sk_state == TCP_CLOSE)
+ mask |= EPOLLHUP;
+
+ /*
+ * we set writable also when the other side has shut down the
+ * connection. This prevents stuck sockets.
+ */
+ if (unix_writable(sk))
+ mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
+
+ return mask;
+}
+
+static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
+ poll_table *wait)
+{
+ struct sock *sk = sock->sk, *other;
+ unsigned int writable;
+ __poll_t mask;
+
+ sock_poll_wait(file, sock, wait);
+ mask = 0;
+
+ /* exceptional events? */
+ if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
+ mask |= EPOLLERR |
+ (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
+
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
+ if (sk->sk_shutdown == SHUTDOWN_MASK)
+ mask |= EPOLLHUP;
+
+ /* readable? */
+ if (!skb_queue_empty(&sk->sk_receive_queue))
+ mask |= EPOLLIN | EPOLLRDNORM;
+
+ /* Connection-based need to check for termination and startup */
+ if (sk->sk_type == SOCK_SEQPACKET) {
+ if (sk->sk_state == TCP_CLOSE)
+ mask |= EPOLLHUP;
+ /* connection hasn't started yet? */
+ if (sk->sk_state == TCP_SYN_SENT)
+ return mask;
+ }
+
+ /* No write status requested, avoid expensive OUT tests. */
+ if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT)))
+ return mask;
+
+ writable = unix_writable(sk);
+ 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);
+ }
+
+ if (writable)
+ mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
+ else
+ sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+
+ return mask;
+}
+
+#ifdef CONFIG_PROC_FS
+
+#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))
+
+static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
+{
+ unsigned long offset = get_offset(*pos);
+ unsigned long bucket = get_bucket(*pos);
+ struct sock *sk;
+ unsigned long count = 0;
+
+ for (sk = sk_head(&unix_socket_table[bucket]); sk; sk = sk_next(sk)) {
+ if (sock_net(sk) != seq_file_net(seq))
+ continue;
+ 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;
+ }
+
+ 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));
+
+ return NULL;
+}
+
+static void *unix_seq_start(struct seq_file *seq, loff_t *pos)
+ __acquires(unix_table_lock)
+{
+ spin_lock(&unix_table_lock);
+
+ if (!*pos)
+ return SEQ_START_TOKEN;
+
+ if (get_bucket(*pos) >= ARRAY_SIZE(unix_socket_table))
+ return NULL;
+
+ return unix_next_socket(seq, NULL, pos);
+}
+
+static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ ++*pos;
+ return unix_next_socket(seq, v, pos);
+}
+
+static void unix_seq_stop(struct seq_file *seq, void *v)
+ __releases(unix_table_lock)
+{
+ spin_unlock(&unix_table_lock);
+}
+
+static int unix_seq_show(struct seq_file *seq, void *v)
+{
+
+ if (v == SEQ_START_TOKEN)
+ seq_puts(seq, "Num RefCount Protocol Flags Type St "
+ "Inode Path\n");
+ else {
+ struct sock *s = v;
+ struct unix_sock *u = unix_sk(s);
+ unix_state_lock(s);
+
+ seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu",
+ s,
+ refcount_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] ?:
+ '@');
+ }
+ unix_state_unlock(s);
+ seq_putc(seq, '\n');
+ }
+
+ return 0;
+}
+
+static const struct seq_operations unix_seq_ops = {
+ .start = unix_seq_start,
+ .next = unix_seq_next,
+ .stop = unix_seq_stop,
+ .show = unix_seq_show,
+};
+#endif
+
+static const struct net_proto_family unix_family_ops = {
+ .family = PF_UNIX,
+ .create = unix_create,
+ .owner = THIS_MODULE,
+};
+
+
+static int __net_init unix_net_init(struct net *net)
+{
+ int error = -ENOMEM;
+
+ net->unx.sysctl_max_dgram_qlen = 10;
+ if (unix_sysctl_register(net))
+ goto out;
+
+#ifdef CONFIG_PROC_FS
+ if (!proc_create_net("unix", 0, net->proc_net, &unix_seq_ops,
+ sizeof(struct seq_net_private))) {
+ unix_sysctl_unregister(net);
+ goto out;
+ }
+#endif
+ error = 0;
+out:
+ return error;
+}
+
+static void __net_exit unix_net_exit(struct net *net)
+{
+ unix_sysctl_unregister(net);
+ remove_proc_entry("unix", net->proc_net);
+}
+
+static struct pernet_operations unix_net_ops = {
+ .init = unix_net_init,
+ .exit = unix_net_exit,
+};
+
+static int __init af_unix_init(void)
+{
+ int rc = -1;
+
+ BUILD_BUG_ON(sizeof(struct unix_skb_parms) > FIELD_SIZEOF(struct sk_buff, cb));
+
+ rc = proto_register(&unix_proto, 1);
+ if (rc != 0) {
+ pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__);
+ goto out;
+ }
+
+ sock_register(&unix_family_ops);
+ register_pernet_subsys(&unix_net_ops);
+out:
+ return rc;
+}
+
+static void __exit af_unix_exit(void)
+{
+ sock_unregister(PF_UNIX);
+ proto_unregister(&unix_proto);
+ unregister_pernet_subsys(&unix_net_ops);
+}
+
+/* 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);
+module_exit(af_unix_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NETPROTO(PF_UNIX);