diff options
Diffstat (limited to 'net/unix/af_unix.c')
| -rw-r--r-- | net/unix/af_unix.c | 2467 |
1 files changed, 2467 insertions, 0 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c new file mode 100644 index 000000000..06430598c --- /dev/null +++ b/net/unix/af_unix.c @@ -0,0 +1,2467 @@ +/* + * 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.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> +#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> + +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) +{ + memcpy(UNIXSID(skb), &scm->secid, sizeof(u32)); +} + +static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) +{ + scm->secid = *UNIXSID(skb); +} +#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) +{ } +#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 (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. + */ + +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; +} + +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) +{ + struct socket_wq *wq; + + rcu_read_lock(); + if (unix_writable(sk)) { + wq = rcu_dereference(sk->sk_wq); + if (wq_has_sleeper(wq)) + wake_up_interruptible_sync_poll(&wq->wait, + POLLOUT | POLLWRNORM | POLLWRBAND); + 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(atomic_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); + } + 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 */ + 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); +static int unix_getname(struct socket *, struct sockaddr *, int *, int); +static unsigned int unix_poll(struct file *, struct socket *, poll_table *); +static unsigned int 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 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->readlock)) + return -EINTR; + + sk->sk_peek_off = val; + mutex_unlock(&u->readlock); + + 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 = sock_no_sendpage, + .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), +}; + +/* + * 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; + +static struct sock *unix_create1(struct net *net, struct socket *sock) +{ + 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); + if (!sk) + goto out; + + sock_init_data(sock, sk); + lockdep_set_class(&sk->sk_receive_queue.lock, + &af_unix_sk_receive_queue_lock_key); + + 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->readlock); /* single task reading lock */ + init_waitqueue_head(&u->peer_wait); + 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; + 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) ? 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->readlock); + 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; + atomic_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->readlock); + 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; + + err = -EINVAL; + if (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; + + err = mutex_lock_interruptible(&u->readlock); + if (err) + goto out; + + 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); + + if (sun_path[0]) { + struct path path; + 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; + unix_release_addr(addr); + goto out_up; + } + 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->readlock); +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; + + 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_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); + 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) { + atomic_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) +{ + 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 *uaddr_len, 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; + *uaddr_len = sizeof(short); + } else { + struct unix_address *addr = u->addr; + + *uaddr_len = addr->len; + memcpy(sunaddr, addr->name, *uaddr_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->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); +} + +#define MAX_RECURSION_LEVEL 4 + +static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) +{ + int i; + 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; + + /* + * 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; + + if (unix_sock_count) { + for (i = scm->fp->count - 1; i >= 0; i--) + unix_inflight(scm->fp->fp[i]); + } + return max_level; +} + +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; + if (scm->fp && send_fds) + err = unix_attach_fds(scm, skb); + + skb->destructor = unix_destruct_scm; + return err; +} + +/* + * 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 (test_bit(SOCK_PASSCRED, &sock->flags) || + !other->sk_socket || + test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) { + UNIXCB(skb).pid = get_pid(task_tgid(current)); + current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid); + } +} + +/* + * 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 max_level; + int data_len = 0; + + 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; + max_level = err + 1; + unix_get_secdata(&scm, skb); + + 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; + } + + unix_state_lock(other); + 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 + */ + unix_state_unlock(other); + sock_put(other); + + err = 0; + unix_state_lock(sk); + if (unix_peer(sk) == other) { + unix_peer(sk) = NULL; + 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; + } + + if (unix_peer(other) != sk && unix_recvq_full(other)) { + 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; + } + + if (sock_flag(other, SOCK_RCVTSTAMP)) + __net_timestamp(skb); + maybe_add_creds(skb, sock, other); + skb_queue_tail(&other->sk_receive_queue, skb); + if (max_level > unix_sk(other)->recursion_level) + unix_sk(other)->recursion_level = max_level; + unix_state_unlock(other); + other->sk_data_ready(other); + sock_put(other); + scm_destroy(&scm); + return len; + +out_unlock: + 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 minimun 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 max_level; + 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; + } + max_level = err + 1; + 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); + if (max_level > unix_sk(other)->recursion_level) + unix_sk(other)->recursion_level = max_level; + 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 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); + int noblock = flags & MSG_DONTWAIT; + struct sk_buff *skb; + int err; + int peeked, skip; + + err = -EOPNOTSUPP; + if (flags&MSG_OOB) + goto out; + + err = mutex_lock_interruptible(&u->readlock); + 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; + goto out; + } + + skip = sk_peek_offset(sk, flags); + + skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err); + 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); + goto out_unlock; + } + + wake_up_interruptible_sync_poll(&u->peer_wait, + POLLOUT | POLLWRNORM | POLLWRBAND); + + 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); +out_unlock: + mutex_unlock(&u->readlock); +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) +{ + DEFINE_WAIT(wait); + + unix_state_lock(sk); + + for (;;) { + prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); + + if (skb_peek_tail(&sk->sk_receive_queue) != last || + sk->sk_err || + (sk->sk_shutdown & RCV_SHUTDOWN) || + signal_pending(current) || + !timeo) + break; + + set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); + unix_state_unlock(sk); + timeo = freezable_schedule_timeout(timeo); + unix_state_lock(sk); + + if (sock_flag(sk, SOCK_DEAD)) + break; + + clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags); + } + + 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; +} + +static int unix_stream_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); + DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name); + int copied = 0; + int noblock = flags & MSG_DONTWAIT; + int check_creds = 0; + int target; + int err = 0; + long timeo; + int skip; + + 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); + timeo = sock_rcvtimeo(sk, noblock); + + /* Lock the socket to prevent queue disordering + * while sleeps in memcpy_tomsg + */ + + memset(&scm, 0, sizeof(scm)); + + err = mutex_lock_interruptible(&u->readlock); + 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; + goto out; + } + + do { + int chunk; + struct sk_buff *skb, *last; + + unix_state_lock(sk); + if (sock_flag(sk, SOCK_DEAD)) { + err = -ECONNRESET; + goto unlock; + } + last = skb = skb_peek(&sk->sk_receive_queue); +again: + if (skb == NULL) { + unix_sk(sk)->recursion_level = 0; + 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); + err = -EAGAIN; + if (!timeo) + break; + mutex_unlock(&u->readlock); + + timeo = unix_stream_data_wait(sk, timeo, last); + + if (signal_pending(current) + || mutex_lock_interruptible(&u->readlock)) { + err = sock_intr_errno(timeo); + goto out; + } + + continue; + unlock: + unix_state_unlock(sk); + break; + } + + skip = sk_peek_offset(sk, flags); + while (skip >= unix_skb_len(skb)) { + skip -= unix_skb_len(skb); + last = skb; + 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 ((UNIXCB(skb).pid != scm.pid) || + !uid_eq(UNIXCB(skb).uid, scm.creds.uid) || + !gid_eq(UNIXCB(skb).gid, scm.creds.gid)) + break; + } else if (test_bit(SOCK_PASSCRED, &sock->flags)) { + /* Copy credentials */ + scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); + check_creds = 1; + } + + /* Copy address just once */ + if (sunaddr) { + unix_copy_addr(msg, skb->sk); + sunaddr = NULL; + } + + chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size); + if (skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip, + msg, chunk)) { + if (copied == 0) + copied = -EFAULT; + break; + } + copied += chunk; + size -= chunk; + + /* 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); + + break; + } + } while (size); + + mutex_unlock(&u->readlock); + scm_recv(sock, msg, &scm, flags); +out: + return copied ? : err; +} + +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_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; + default: + err = -ENOIOCTLCMD; + break; + } + return err; +} + +static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table *wait) +{ + struct sock *sk = sock->sk; + unsigned int mask; + + sock_poll_wait(file, sk_sleep(sk), wait); + mask = 0; + + /* exceptional events? */ + if (sk->sk_err) + mask |= POLLERR; + if (sk->sk_shutdown == SHUTDOWN_MASK) + mask |= POLLHUP; + if (sk->sk_shutdown & RCV_SHUTDOWN) + mask |= POLLRDHUP | POLLIN | POLLRDNORM; + + /* readable? */ + if (!skb_queue_empty(&sk->sk_receive_queue)) + mask |= POLLIN | POLLRDNORM; + + /* 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 |= 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; +} + +static unsigned int unix_dgram_poll(struct file *file, struct socket *sock, + poll_table *wait) +{ + struct sock *sk = sock->sk, *other; + unsigned int mask, writable; + + sock_poll_wait(file, sk_sleep(sk), wait); + mask = 0; + + /* exceptional events? */ + if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue)) + mask |= POLLERR | + (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0); + + if (sk->sk_shutdown & RCV_SHUTDOWN) + mask |= POLLRDHUP | POLLIN | POLLRDNORM; + if (sk->sk_shutdown == SHUTDOWN_MASK) + mask |= POLLHUP; + + /* readable? */ + if (!skb_queue_empty(&sk->sk_receive_queue)) + 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; + } + + /* No write status requested, avoid expensive OUT tests. */ + if (!(poll_requested_events(wait) & (POLLWRBAND|POLLWRNORM|POLLOUT))) + return mask; + + writable = unix_writable(sk); + 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; + } + sock_put(other); + } + + if (writable) + mask |= POLLOUT | POLLWRNORM | POLLWRBAND; + else + set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags); + + 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, + 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]); + } + 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, +}; + +static int unix_seq_open(struct inode *inode, struct file *file) +{ + return seq_open_net(inode, file, &unix_seq_ops, + sizeof(struct seq_net_private)); +} + +static const struct file_operations unix_seq_fops = { + .owner = THIS_MODULE, + .open = unix_seq_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_net, +}; + +#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("unix", 0, net->proc_net, &unix_seq_fops)) { + 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); |