| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * NET4: Implementation of BSD Unix domain sockets. |
| * |
| * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk> |
| * |
| * 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> |
| |
| #include "scm.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(const struct sock *sk) |
| { |
| return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog; |
| } |
| |
| static inline int unix_recvq_full_lockless(const struct sock *sk) |
| { |
| return skb_queue_len_lockless(&sk->sk_receive_queue) > |
| READ_ONCE(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) |
| { |
| *hashp = 0; |
| |
| 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)) |
| return s; |
| } |
| return NULL; |
| } |
| |
| 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); |
| #ifdef CONFIG_COMPAT |
| static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg); |
| #endif |
| 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; |
| } |
| |
| #ifdef CONFIG_PROC_FS |
| static void unix_show_fdinfo(struct seq_file *m, struct socket *sock) |
| { |
| struct sock *sk = sock->sk; |
| struct unix_sock *u; |
| |
| if (sk) { |
| u = unix_sk(sock->sk); |
| seq_printf(m, "scm_fds: %u\n", READ_ONCE(u->scm_stat.nr_fds)); |
| } |
| } |
| #else |
| #define unix_show_fdinfo NULL |
| #endif |
| |
| 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, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = unix_compat_ioctl, |
| #endif |
| .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, |
| .show_fdinfo = unix_show_fdinfo, |
| }; |
| |
| 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, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = unix_compat_ioctl, |
| #endif |
| .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, |
| .show_fdinfo = unix_show_fdinfo, |
| }; |
| |
| 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, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = unix_compat_ioctl, |
| #endif |
| .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, |
| .show_fdinfo = unix_show_fdinfo, |
| }; |
| |
| 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); |
| memset(&u->scm_stat, 0, sizeof(struct scm_stat)); |
| 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); |
| smp_store_release(&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); |
| smp_store_release(&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 |
| * |
| * The contents of *(otheru->addr) and otheru->path |
| * are seen fully set up here, since we have found |
| * otheru in hash under unix_table_lock. Insertion |
| * into the hash chain we'd found it in had been done |
| * in an earlier critical area protected by unix_table_lock, |
| * the same one where we'd set *(otheru->addr) contents, |
| * as well as otheru->path and otheru->addr itself. |
| * |
| * Using smp_store_release() here to set newu->addr |
| * is enough to make those stores, as well as stores |
| * to newu->path visible to anyone who gets newu->addr |
| * by smp_load_acquire(). IOW, the same warranties |
| * as for unix_sock instances bound in unix_bind() or |
| * in unix_autobind(). |
| */ |
| if (otheru->path.dentry) { |
| path_get(&otheru->path); |
| newu->path = otheru->path; |
| } |
| refcount_inc(&otheru->addr->refcnt); |
| smp_store_release(&newu->addr, otheru->addr); |
| |
| /* 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_address *addr; |
| 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); |
| } |
| |
| addr = smp_load_acquire(&unix_sk(sk)->addr); |
| if (!addr) { |
| sunaddr->sun_family = AF_UNIX; |
| sunaddr->sun_path[0] = 0; |
| err = sizeof(short); |
| } else { |
| err = addr->len; |
| memcpy(sunaddr, addr->name, addr->len); |
| } |
| sock_put(sk); |
| out: |
| return err; |
| } |
| |
| 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); |
| } |
| |
| static void scm_stat_add(struct sock *sk, struct sk_buff *skb) |
| { |
| struct scm_fp_list *fp = UNIXCB(skb).fp; |
| struct unix_sock *u = unix_sk(sk); |
| |
| lockdep_assert_held(&sk->sk_receive_queue.lock); |
| |
| if (unlikely(fp && fp->count)) |
| u->scm_stat.nr_fds += fp->count; |
| } |
| |
| static void scm_stat_del(struct sock *sk, struct sk_buff *skb) |
| { |
| struct scm_fp_list *fp = UNIXCB(skb).fp; |
| struct unix_sock *u = unix_sk(sk); |
| |
| lockdep_assert_held(&sk->sk_receive_queue.lock); |
| |
| if (unlikely(fp && fp->count)) |
| u->scm_stat.nr_fds -= fp->count; |
| } |
| |
| /* |
| * 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_lockless(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); |
| spin_lock(&other->sk_receive_queue.lock); |
| scm_stat_add(other, skb); |
| __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); |
| 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); |
| spin_lock(&other->sk_receive_queue.lock); |
| scm_stat_add(other, skb); |
| __skb_queue_tail(&other->sk_receive_queue, skb); |
| spin_unlock(&other->sk_receive_queue.lock); |
| 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_address *addr = smp_load_acquire(&unix_sk(sk)->addr); |
| |
| if (addr) { |
| msg->msg_namelen = addr->len; |
| memcpy(msg->msg_name, addr->name, 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 skip; |
| int err; |
| |
| 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, &sk->sk_receive_queue, flags, |
| scm_stat_del, &skip, &err, &last); |
| if (skb) |
| break; |
| |
| mutex_unlock(&u->iolock); |
| |
| if (err != -EAGAIN) |
| break; |
| } while (timeo && |
| !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue, |
| &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) { |
| spin_lock(&sk->sk_receive_queue.lock); |
| scm_stat_del(sk, skb); |
| spin_unlock(&sk->sk_receive_queue.lock); |
| 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; |
| |
| if (!smp_load_acquire(&unix_sk(sk)->addr)) |
| return -ENOENT; |
| |
| path = unix_sk(sk)->path; |
| if (!path.dentry) |
| return -ENOENT; |
| |
| path_get(&path); |
| |
| 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; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) |
| { |
| return unix_ioctl(sock, cmd, (unsigned long)compat_ptr(arg)); |
| } |
| #endif |
| |
| 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_lockless(&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_lockless(&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_lockless(&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) { // under unix_table_lock here |
| 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) > sizeof_field(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); |