| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Linus Torvalds (pre-git) | 4503 | 25.45% | 99 | 21.15% |
| Kuniyuki Iwashima | 4225 | 23.88% | 74 | 15.81% |
| David S. Miller | 958 | 5.41% | 17 | 3.63% |
| Rainer Weikusat | 782 | 4.42% | 11 | 2.35% |
| Eric Dumazet | 759 | 4.29% | 38 | 8.12% |
| Rao Shoaib | 716 | 4.05% | 4 | 0.85% |
| Hannes Frederic Sowa | 551 | 3.11% | 2 | 0.43% |
| Al Viro | 483 | 2.73% | 21 | 4.49% |
| Kirill V Tkhai | 386 | 2.18% | 5 | 1.07% |
| Eric W. Biedermann | 341 | 1.93% | 8 | 1.71% |
| Arnaldo Carvalho de Melo | 307 | 1.74% | 11 | 2.35% |
| Américo Wang | 293 | 1.66% | 7 | 1.50% |
| Pavel Emelyanov | 270 | 1.53% | 12 | 2.56% |
| Jiang Wang | 210 | 1.19% | 3 | 0.64% |
| Linus Torvalds | 204 | 1.15% | 12 | 2.56% |
| Stephen Hemminger | 196 | 1.11% | 3 | 0.64% |
| Jens Axboe | 180 | 1.02% | 6 | 1.28% |
| Andrey Vagin | 170 | 0.96% | 2 | 0.43% |
| James Morris | 168 | 0.95% | 5 | 1.07% |
| Michal Luczaj | 157 | 0.89% | 1 | 0.21% |
| Denis V. Lunev | 142 | 0.80% | 3 | 0.64% |
| Catherine Zhang | 141 | 0.80% | 2 | 0.43% |
| Daan De Meyer | 126 | 0.71% | 1 | 0.21% |
| David Howells | 117 | 0.66% | 4 | 0.85% |
| Alexander Mikhalitsyn | 111 | 0.63% | 3 | 0.64% |
| Miklos Szeredi | 87 | 0.49% | 6 | 1.28% |
| Rusty Russell | 86 | 0.49% | 1 | 0.21% |
| Benjamin LaHaise | 84 | 0.47% | 4 | 0.85% |
| Arnd Bergmann | 80 | 0.45% | 1 | 0.21% |
| Daniel Borkmann | 68 | 0.38% | 1 | 0.21% |
| Alban Crequy | 55 | 0.31% | 3 | 0.64% |
| Stephen D. Smalley | 54 | 0.31% | 1 | 0.21% |
| Steven Dake | 53 | 0.30% | 1 | 0.21% |
| Aaron Conole | 49 | 0.28% | 1 | 0.21% |
| Herbert Pötzl | 41 | 0.23% | 1 | 0.21% |
| Florian Zumbiehl | 38 | 0.21% | 1 | 0.21% |
| Christoph Hellwig | 33 | 0.19% | 6 | 1.28% |
| Paolo Abeni | 32 | 0.18% | 3 | 0.64% |
| Benjamin Poirier | 26 | 0.15% | 1 | 0.21% |
| Mateusz Jurczyk | 20 | 0.11% | 1 | 0.21% |
| Andi Kleen | 18 | 0.10% | 1 | 0.21% |
| Sabrina Dubroca | 16 | 0.09% | 2 | 0.43% |
| OGAWA Hirofumi | 16 | 0.09% | 1 | 0.21% |
| Gao Feng | 14 | 0.08% | 2 | 0.43% |
| Sasha Levin | 14 | 0.08% | 1 | 0.21% |
| Qian Cai | 14 | 0.08% | 1 | 0.21% |
| Hideaki Yoshifuji / 吉藤英明 | 13 | 0.07% | 4 | 0.85% |
| Andrew Morton | 13 | 0.07% | 2 | 0.43% |
| Jacob E Keller | 12 | 0.07% | 2 | 0.43% |
| Peter Zijlstra | 12 | 0.07% | 2 | 0.43% |
| Xi Wang | 12 | 0.07% | 1 | 0.21% |
| Solar Designer | 12 | 0.07% | 1 | 0.21% |
| Kees Cook | 12 | 0.07% | 1 | 0.21% |
| Tobias Klauser | 11 | 0.06% | 2 | 0.43% |
| Wang Weidong | 11 | 0.06% | 1 | 0.21% |
| Tomoki Sekiyama | 11 | 0.06% | 1 | 0.21% |
| Jean Sacren | 10 | 0.06% | 1 | 0.21% |
| Sjur Brændeland | 8 | 0.05% | 1 | 0.21% |
| Ingo Molnar | 8 | 0.05% | 3 | 0.64% |
| Davide Libenzi | 8 | 0.05% | 1 | 0.21% |
| Christian Brauner | 8 | 0.05% | 3 | 0.64% |
| Irenge Jules Bashizi | 8 | 0.05% | 1 | 0.21% |
| Paul Moore | 8 | 0.05% | 1 | 0.21% |
| Cyrill V. Gorcunov | 7 | 0.04% | 1 | 0.21% |
| Oliver Hartkopp | 7 | 0.04% | 1 | 0.21% |
| Greg Kroah-Hartman | 6 | 0.03% | 2 | 0.43% |
| Jakub Kiciński | 6 | 0.03% | 2 | 0.43% |
| Shaun Pereira | 6 | 0.03% | 1 | 0.21% |
| Rémi Denis-Courmont | 6 | 0.03% | 1 | 0.21% |
| Vladimir Davydov | 6 | 0.03% | 1 | 0.21% |
| Ray Lee | 5 | 0.03% | 1 | 0.21% |
| Jan Harkes | 5 | 0.03% | 1 | 0.21% |
| Denys Vlasenko | 5 | 0.03% | 1 | 0.21% |
| Karsten Graul | 4 | 0.02% | 1 | 0.21% |
| Vito Caputo | 4 | 0.02% | 1 | 0.21% |
| Elena Reshetova | 4 | 0.02% | 3 | 0.64% |
| Matthew Dawson | 4 | 0.02% | 1 | 0.21% |
| Breno Leitão | 3 | 0.02% | 1 | 0.21% |
| Colin Cross | 3 | 0.02% | 1 | 0.21% |
| Eric Paris | 3 | 0.02% | 1 | 0.21% |
| Isaac Boukris | 3 | 0.02% | 1 | 0.21% |
| Philippe De Muyter | 2 | 0.01% | 1 | 0.21% |
| Anton Blanchard | 2 | 0.01% | 1 | 0.21% |
| Tetsuo Handa | 2 | 0.01% | 1 | 0.21% |
| Gustavo A. R. Silva | 2 | 0.01% | 1 | 0.21% |
| Dipankar Sarma | 2 | 0.01% | 1 | 0.21% |
| Alexey Dobriyan | 2 | 0.01% | 1 | 0.21% |
| Jason Baron | 2 | 0.01% | 1 | 0.21% |
| Harvey Harrison | 2 | 0.01% | 1 | 0.21% |
| Ilpo Järvinen | 2 | 0.01% | 1 | 0.21% |
| Patrick McHardy | 2 | 0.01% | 1 | 0.21% |
| Thomas Gleixner | 2 | 0.01% | 1 | 0.21% |
| Pankaj Bharadiya | 1 | 0.01% | 1 | 0.21% |
| John Fastabend | 1 | 0.01% | 1 | 0.21% |
| Neil Horman | 1 | 0.01% | 1 | 0.21% |
| Jason A. Donenfeld | 1 | 0.01% | 1 | 0.21% |
| Alexey Moiseytsev | 1 | 0.01% | 1 | 0.21% |
| Dan Rosenberg | 1 | 0.01% | 1 | 0.21% |
| gushengxian | 1 | 0.01% | 1 | 0.21% |
| Herbert Xu | 1 | 0.01% | 1 | 0.21% |
| Alan Cox | 1 | 0.01% | 1 | 0.21% |
| Jan Blunck | 1 | 0.01% | 1 | 0.21% |
| Stephen Boyd | 1 | 0.01% | 1 | 0.21% |
| Joe Perches | 1 | 0.01% | 1 | 0.21% |
| David Woodhouse | 1 | 0.01% | 1 | 0.21% |
| Total | 17693 | 468 |
// 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/filter.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/splice.h> #include <linux/freezer.h> #include <linux/file.h> #include <linux/btf_ids.h> #include <linux/bpf-cgroup.h> static atomic_long_t unix_nr_socks; static struct hlist_head bsd_socket_buckets[UNIX_HASH_SIZE / 2]; static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2]; /* SMP locking strategy: * hash table is protected with spinlock. * each socket state is protected by separate spinlock. */ #ifdef CONFIG_PROVE_LOCKING #define cmp_ptr(l, r) (((l) > (r)) - ((l) < (r))) static int unix_table_lock_cmp_fn(const struct lockdep_map *a, const struct lockdep_map *b) { return cmp_ptr(a, b); } static int unix_state_lock_cmp_fn(const struct lockdep_map *_a, const struct lockdep_map *_b) { const struct unix_sock *a, *b; a = container_of(_a, struct unix_sock, lock.dep_map); b = container_of(_b, struct unix_sock, lock.dep_map); if (a->sk.sk_state == TCP_LISTEN) { /* unix_stream_connect(): Before the 2nd unix_state_lock(), * * 1. a is TCP_LISTEN. * 2. b is not a. * 3. concurrent connect(b -> a) must fail. * * Except for 2. & 3., the b's state can be any possible * value due to concurrent connect() or listen(). * * 2. is detected in debug_spin_lock_before(), and 3. cannot * be expressed as lock_cmp_fn. */ switch (b->sk.sk_state) { case TCP_CLOSE: case TCP_ESTABLISHED: case TCP_LISTEN: return -1; default: /* Invalid case. */ return 0; } } /* Should never happen. Just to be symmetric. */ if (b->sk.sk_state == TCP_LISTEN) { switch (b->sk.sk_state) { case TCP_CLOSE: case TCP_ESTABLISHED: return 1; default: return 0; } } /* unix_state_double_lock(): ascending address order. */ return cmp_ptr(a, b); } static int unix_recvq_lock_cmp_fn(const struct lockdep_map *_a, const struct lockdep_map *_b) { const struct sock *a, *b; a = container_of(_a, struct sock, sk_receive_queue.lock.dep_map); b = container_of(_b, struct sock, sk_receive_queue.lock.dep_map); /* unix_collect_skb(): listener -> embryo order. */ if (a->sk_state == TCP_LISTEN && unix_sk(b)->listener == a) return -1; /* Should never happen. Just to be symmetric. */ if (b->sk_state == TCP_LISTEN && unix_sk(a)->listener == b) return 1; return 0; } #endif static unsigned int unix_unbound_hash(struct sock *sk) { unsigned long hash = (unsigned long)sk; hash ^= hash >> 16; hash ^= hash >> 8; hash ^= sk->sk_type; return hash & UNIX_HASH_MOD; } static unsigned int unix_bsd_hash(struct inode *i) { return i->i_ino & UNIX_HASH_MOD; } static unsigned int unix_abstract_hash(struct sockaddr_un *sunaddr, int addr_len, int type) { __wsum csum = csum_partial(sunaddr, addr_len, 0); unsigned int hash; hash = (__force unsigned int)csum_fold(csum); hash ^= hash >> 8; hash ^= type; return UNIX_HASH_MOD + 1 + (hash & UNIX_HASH_MOD); } static void unix_table_double_lock(struct net *net, unsigned int hash1, unsigned int hash2) { if (hash1 == hash2) { spin_lock(&net->unx.table.locks[hash1]); return; } if (hash1 > hash2) swap(hash1, hash2); spin_lock(&net->unx.table.locks[hash1]); spin_lock(&net->unx.table.locks[hash2]); } static void unix_table_double_unlock(struct net *net, unsigned int hash1, unsigned int hash2) { if (hash1 == hash2) { spin_unlock(&net->unx.table.locks[hash1]); return; } spin_unlock(&net->unx.table.locks[hash1]); spin_unlock(&net->unx.table.locks[hash2]); } #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 */ 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_lockless(const struct sock *sk) { return skb_queue_len_lockless(&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 struct unix_address *unix_create_addr(struct sockaddr_un *sunaddr, int addr_len) { struct unix_address *addr; addr = kmalloc(sizeof(*addr) + addr_len, GFP_KERNEL); if (!addr) return NULL; refcount_set(&addr->refcnt, 1); addr->len = addr_len; memcpy(addr->name, sunaddr, addr_len); return addr; } 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_validate_addr(struct sockaddr_un *sunaddr, int addr_len) { if (addr_len <= offsetof(struct sockaddr_un, sun_path) || addr_len > sizeof(*sunaddr)) return -EINVAL; if (sunaddr->sun_family != AF_UNIX) return -EINVAL; return 0; } static int unix_mkname_bsd(struct sockaddr_un *sunaddr, int addr_len) { struct sockaddr_storage *addr = (struct sockaddr_storage *)sunaddr; short offset = offsetof(struct sockaddr_storage, __data); BUILD_BUG_ON(offset != offsetof(struct sockaddr_un, sun_path)); /* 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 because syscall functions always pass * a pointer of struct sockaddr_storage which has a bigger buffer * than 108. Also, we must terminate sun_path for strlen() in * getname_kernel(). */ addr->__data[addr_len - offset] = 0; /* Don't pass sunaddr->sun_path to strlen(). Otherwise, 108 will * cause panic if CONFIG_FORTIFY_SOURCE=y. Let __fortify_strlen() * know the actual buffer. */ return strlen(addr->__data) + offset + 1; } static void __unix_remove_socket(struct sock *sk) { sk_del_node_init(sk); } static void __unix_insert_socket(struct net *net, struct sock *sk) { DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk)); sk_add_node(sk, &net->unx.table.buckets[sk->sk_hash]); } static void __unix_set_addr_hash(struct net *net, struct sock *sk, struct unix_address *addr, unsigned int hash) { __unix_remove_socket(sk); smp_store_release(&unix_sk(sk)->addr, addr); sk->sk_hash = hash; __unix_insert_socket(net, sk); } static void unix_remove_socket(struct net *net, struct sock *sk) { spin_lock(&net->unx.table.locks[sk->sk_hash]); __unix_remove_socket(sk); spin_unlock(&net->unx.table.locks[sk->sk_hash]); } static void unix_insert_unbound_socket(struct net *net, struct sock *sk) { spin_lock(&net->unx.table.locks[sk->sk_hash]); __unix_insert_socket(net, sk); spin_unlock(&net->unx.table.locks[sk->sk_hash]); } static void unix_insert_bsd_socket(struct sock *sk) { spin_lock(&bsd_socket_locks[sk->sk_hash]); sk_add_bind_node(sk, &bsd_socket_buckets[sk->sk_hash]); spin_unlock(&bsd_socket_locks[sk->sk_hash]); } static void unix_remove_bsd_socket(struct sock *sk) { if (!hlist_unhashed(&sk->sk_bind_node)) { spin_lock(&bsd_socket_locks[sk->sk_hash]); __sk_del_bind_node(sk); spin_unlock(&bsd_socket_locks[sk->sk_hash]); sk_node_init(&sk->sk_bind_node); } } static struct sock *__unix_find_socket_byname(struct net *net, struct sockaddr_un *sunname, int len, unsigned int hash) { struct sock *s; sk_for_each(s, &net->unx.table.buckets[hash]) { struct unix_sock *u = unix_sk(s); 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, unsigned int hash) { struct sock *s; spin_lock(&net->unx.table.locks[hash]); s = __unix_find_socket_byname(net, sunname, len, hash); if (s) sock_hold(s); spin_unlock(&net->unx.table.locks[hash]); return s; } static struct sock *unix_find_socket_byinode(struct inode *i) { unsigned int hash = unix_bsd_hash(i); struct sock *s; spin_lock(&bsd_socket_locks[hash]); sk_for_each_bound(s, &bsd_socket_buckets[hash]) { struct dentry *dentry = unix_sk(s)->path.dentry; if (dentry && d_backing_inode(dentry) == i) { sock_hold(s); spin_unlock(&bsd_socket_locks[hash]); return s; } } spin_unlock(&bsd_socket_locks[hash]); return NULL; } /* 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_lockless(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, unsigned char state) { return state != TCP_LISTEN && (refcount_read(&sk->sk_wmem_alloc) << 2) <= READ_ONCE(sk->sk_sndbuf); } static void unix_write_space(struct sock *sk) { struct socket_wq *wq; rcu_read_lock(); if (unix_writable(sk, READ_ONCE(sk->sk_state))) { wq = rcu_dereference(sk->sk_wq); if (skwq_has_sleeper(wq)) wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); sk_wake_async_rcu(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) { WRITE_ONCE(other->sk_err, ECONNRESET); 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); DEBUG_NET_WARN_ON_ONCE(refcount_read(&sk->sk_wmem_alloc)); DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk)); DEBUG_NET_WARN_ON_ONCE(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); sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); #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 sock *skpair; struct sk_buff *skb; struct path path; int state; unix_remove_socket(sock_net(sk), sk); unix_remove_bsd_socket(sk); /* Clear state */ unix_state_lock(sk); sock_orphan(sk); WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); path = u->path; u->path.dentry = NULL; u->path.mnt = NULL; state = sk->sk_state; WRITE_ONCE(sk->sk_state, TCP_CLOSE); skpair = unix_peer(sk); unix_peer(sk) = NULL; unix_state_unlock(sk); #if IS_ENABLED(CONFIG_AF_UNIX_OOB) if (u->oob_skb) { kfree_skb(u->oob_skb); u->oob_skb = NULL; } #endif wake_up_interruptible_all(&u->peer_wait); if (skpair != NULL) { if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) { unix_state_lock(skpair); /* No more writes */ WRITE_ONCE(skpair->sk_shutdown, SHUTDOWN_MASK); if (!skb_queue_empty_lockless(&sk->sk_receive_queue) || embrion) WRITE_ONCE(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 */ } /* 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 (READ_ONCE(unix_tot_inflight)) unix_gc(); /* Garbage collect fds */ } static void init_peercred(struct sock *sk) { sk->sk_peer_pid = get_pid(task_tgid(current)); sk->sk_peer_cred = get_current_cred(); } static void update_peercred(struct sock *sk) { const struct cred *old_cred; struct pid *old_pid; spin_lock(&sk->sk_peer_lock); old_pid = sk->sk_peer_pid; old_cred = sk->sk_peer_cred; init_peercred(sk); spin_unlock(&sk->sk_peer_lock); put_pid(old_pid); put_cred(old_cred); } static void copy_peercred(struct sock *sk, struct sock *peersk) { lockdep_assert_held(&unix_sk(peersk)->lock); spin_lock(&sk->sk_peer_lock); sk->sk_peer_pid = get_pid(peersk->sk_peer_pid); sk->sk_peer_cred = get_cred(peersk->sk_peer_cred); spin_unlock(&sk->sk_peer_lock); } static int unix_listen(struct socket *sock, int backlog) { int err; struct sock *sk = sock->sk; struct unix_sock *u = unix_sk(sk); err = -EOPNOTSUPP; if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) goto out; /* Only stream/seqpacket sockets accept */ err = -EINVAL; if (!READ_ONCE(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; WRITE_ONCE(sk->sk_state, TCP_LISTEN); /* set credentials so connect can copy them */ update_peercred(sk); err = 0; out_unlock: unix_state_unlock(sk); 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 *, struct proto_accept_arg *arg); 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_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_read_skb(struct sock *sk, skb_read_actor_t recv_actor); static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor); 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); #ifdef CONFIG_PROC_FS static int unix_count_nr_fds(struct sock *sk) { struct sk_buff *skb; struct unix_sock *u; int nr_fds = 0; spin_lock(&sk->sk_receive_queue.lock); skb = skb_peek(&sk->sk_receive_queue); while (skb) { u = unix_sk(skb->sk); nr_fds += atomic_read(&u->scm_stat.nr_fds); skb = skb_peek_next(skb, &sk->sk_receive_queue); } spin_unlock(&sk->sk_receive_queue.lock); return nr_fds; } static void unix_show_fdinfo(struct seq_file *m, struct socket *sock) { struct sock *sk = sock->sk; unsigned char s_state; struct unix_sock *u; int nr_fds = 0; if (sk) { s_state = READ_ONCE(sk->sk_state); u = unix_sk(sk); /* SOCK_STREAM and SOCK_SEQPACKET sockets never change their * sk_state after switching to TCP_ESTABLISHED or TCP_LISTEN. * SOCK_DGRAM is ordinary. So, no lock is needed. */ if (sock->type == SOCK_DGRAM || s_state == TCP_ESTABLISHED) nr_fds = atomic_read(&u->scm_stat.nr_fds); else if (s_state == TCP_LISTEN) nr_fds = unix_count_nr_fds(sk); seq_printf(m, "scm_fds: %u\n", 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, .sendmsg = unix_stream_sendmsg, .recvmsg = unix_stream_recvmsg, .read_skb = unix_stream_read_skb, .mmap = sock_no_mmap, .splice_read = unix_stream_splice_read, .set_peek_off = sk_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, .sendmsg = unix_dgram_sendmsg, .read_skb = unix_read_skb, .recvmsg = unix_dgram_recvmsg, .mmap = sock_no_mmap, .set_peek_off = sk_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, .sendmsg = unix_seqpacket_sendmsg, .recvmsg = unix_seqpacket_recvmsg, .mmap = sock_no_mmap, .set_peek_off = sk_set_peek_off, .show_fdinfo = unix_show_fdinfo, }; static void unix_close(struct sock *sk, long timeout) { /* Nothing to do here, unix socket does not need a ->close(). * This is merely for sockmap. */ } static void unix_unhash(struct sock *sk) { /* Nothing to do here, unix socket does not need a ->unhash(). * This is merely for sockmap. */ } static bool unix_bpf_bypass_getsockopt(int level, int optname) { if (level == SOL_SOCKET) { switch (optname) { case SO_PEERPIDFD: return true; default: return false; } } return false; } struct proto unix_dgram_proto = { .name = "UNIX", .owner = THIS_MODULE, .obj_size = sizeof(struct unix_sock), .close = unix_close, .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt, #ifdef CONFIG_BPF_SYSCALL .psock_update_sk_prot = unix_dgram_bpf_update_proto, #endif }; struct proto unix_stream_proto = { .name = "UNIX-STREAM", .owner = THIS_MODULE, .obj_size = sizeof(struct unix_sock), .close = unix_close, .unhash = unix_unhash, .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt, #ifdef CONFIG_BPF_SYSCALL .psock_update_sk_prot = unix_stream_bpf_update_proto, #endif }; static struct sock *unix_create1(struct net *net, struct socket *sock, int kern, int type) { struct unix_sock *u; struct sock *sk; int err; atomic_long_inc(&unix_nr_socks); if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) { err = -ENFILE; goto err; } if (type == SOCK_STREAM) sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_stream_proto, kern); else /*dgram and seqpacket */ sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_dgram_proto, kern); if (!sk) { err = -ENOMEM; goto err; } sock_init_data(sock, sk); sk->sk_hash = unix_unbound_hash(sk); sk->sk_allocation = GFP_KERNEL_ACCOUNT; sk->sk_write_space = unix_write_space; sk->sk_max_ack_backlog = READ_ONCE(net->unx.sysctl_max_dgram_qlen); sk->sk_destruct = unix_sock_destructor; lock_set_cmp_fn(&sk->sk_receive_queue.lock, unix_recvq_lock_cmp_fn, NULL); u = unix_sk(sk); u->listener = NULL; u->vertex = NULL; u->path.dentry = NULL; u->path.mnt = NULL; spin_lock_init(&u->lock); lock_set_cmp_fn(&u->lock, unix_state_lock_cmp_fn, NULL); 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_unbound_socket(net, sk); sock_prot_inuse_add(net, sk->sk_prot, 1); return sk; err: atomic_long_dec(&unix_nr_socks); return ERR_PTR(err); } static int unix_create(struct net *net, struct socket *sock, int protocol, int kern) { struct sock *sk; 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; fallthrough; case SOCK_DGRAM: sock->ops = &unix_dgram_ops; break; case SOCK_SEQPACKET: sock->ops = &unix_seqpacket_ops; break; default: return -ESOCKTNOSUPPORT; } sk = unix_create1(net, sock, kern, sock->type); if (IS_ERR(sk)) return PTR_ERR(sk); return 0; } static int unix_release(struct socket *sock) { struct sock *sk = sock->sk; if (!sk) return 0; sk->sk_prot->close(sk, 0); unix_release_sock(sk, 0); sock->sk = NULL; return 0; } static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len, int type) { struct inode *inode; struct path path; struct sock *sk; int err; unix_mkname_bsd(sunaddr, addr_len); err = kern_path(sunaddr->sun_path, LOOKUP_FOLLOW, &path); if (err) goto fail; err = path_permission(&path, MAY_WRITE); if (err) goto path_put; err = -ECONNREFUSED; inode = d_backing_inode(path.dentry); if (!S_ISSOCK(inode->i_mode)) goto path_put; sk = unix_find_socket_byinode(inode); if (!sk) goto path_put; err = -EPROTOTYPE; if (sk->sk_type == type) touch_atime(&path); else goto sock_put; path_put(&path); return sk; sock_put: sock_put(sk); path_put: path_put(&path); fail: return ERR_PTR(err); } static struct sock *unix_find_abstract(struct net *net, struct sockaddr_un *sunaddr, int addr_len, int type) { unsigned int hash = unix_abstract_hash(sunaddr, addr_len, type); struct dentry *dentry; struct sock *sk; sk = unix_find_socket_byname(net, sunaddr, addr_len, hash); if (!sk) return ERR_PTR(-ECONNREFUSED); dentry = unix_sk(sk)->path.dentry; if (dentry) touch_atime(&unix_sk(sk)->path); return sk; } static struct sock *unix_find_other(struct net *net, struct sockaddr_un *sunaddr, int addr_len, int type) { struct sock *sk; if (sunaddr->sun_path[0]) sk = unix_find_bsd(sunaddr, addr_len, type); else sk = unix_find_abstract(net, sunaddr, addr_len, type); return sk; } static int unix_autobind(struct sock *sk) { struct unix_sock *u = unix_sk(sk); unsigned int new_hash, old_hash; struct net *net = sock_net(sk); struct unix_address *addr; u32 lastnum, ordernum; int err; err = mutex_lock_interruptible(&u->bindlock); if (err) return err; if (u->addr) goto out; err = -ENOMEM; addr = kzalloc(sizeof(*addr) + offsetof(struct sockaddr_un, sun_path) + 16, GFP_KERNEL); if (!addr) goto out; addr->len = offsetof(struct sockaddr_un, sun_path) + 6; addr->name->sun_family = AF_UNIX; refcount_set(&addr->refcnt, 1); old_hash = sk->sk_hash; ordernum = get_random_u32(); lastnum = ordernum & 0xFFFFF; retry: ordernum = (ordernum + 1) & 0xFFFFF; sprintf(addr->name->sun_path + 1, "%05x", ordernum); new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type); unix_table_double_lock(net, old_hash, new_hash); if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) { unix_table_double_unlock(net, old_hash, new_hash); /* __unix_find_socket_byname() may take long time if many names * are already in use. */ cond_resched(); if (ordernum == lastnum) { /* Give up if all names seems to be in use. */ err = -ENOSPC; unix_release_addr(addr); goto out; } goto retry; } __unix_set_addr_hash(net, sk, addr, new_hash); unix_table_double_unlock(net, old_hash, new_hash); err = 0; out: mutex_unlock(&u->bindlock); return err; } static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr, int addr_len) { umode_t mode = S_IFSOCK | (SOCK_INODE(sk->sk_socket)->i_mode & ~current_umask()); struct unix_sock *u = unix_sk(sk); unsigned int new_hash, old_hash; struct net *net = sock_net(sk); struct mnt_idmap *idmap; struct unix_address *addr; struct dentry *dentry; struct path parent; int err; addr_len = unix_mkname_bsd(sunaddr, addr_len); addr = unix_create_addr(sunaddr, addr_len); if (!addr) return -ENOMEM; /* * Get the parent directory, calculate the hash for last * component. */ dentry = kern_path_create(AT_FDCWD, addr->name->sun_path, &parent, 0); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); goto out; } /* * All right, let's create it. */ idmap = mnt_idmap(parent.mnt); err = security_path_mknod(&parent, dentry, mode, 0); if (!err) err = vfs_mknod(idmap, d_inode(parent.dentry), dentry, mode, 0); if (err) goto out_path; err = mutex_lock_interruptible(&u->bindlock); if (err) goto out_unlink; if (u->addr) goto out_unlock; old_hash = sk->sk_hash; new_hash = unix_bsd_hash(d_backing_inode(dentry)); unix_table_double_lock(net, old_hash, new_hash); u->path.mnt = mntget(parent.mnt); u->path.dentry = dget(dentry); __unix_set_addr_hash(net, sk, addr, new_hash); unix_table_double_unlock(net, old_hash, new_hash); unix_insert_bsd_socket(sk); mutex_unlock(&u->bindlock); done_path_create(&parent, dentry); return 0; out_unlock: mutex_unlock(&u->bindlock); err = -EINVAL; out_unlink: /* failed after successful mknod? unlink what we'd created... */ vfs_unlink(idmap, d_inode(parent.dentry), dentry, NULL); out_path: done_path_create(&parent, dentry); out: unix_release_addr(addr); return err == -EEXIST ? -EADDRINUSE : err; } static int unix_bind_abstract(struct sock *sk, struct sockaddr_un *sunaddr, int addr_len) { struct unix_sock *u = unix_sk(sk); unsigned int new_hash, old_hash; struct net *net = sock_net(sk); struct unix_address *addr; int err; addr = unix_create_addr(sunaddr, addr_len); if (!addr) return -ENOMEM; err = mutex_lock_interruptible(&u->bindlock); if (err) goto out; if (u->addr) { err = -EINVAL; goto out_mutex; } old_hash = sk->sk_hash; new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type); unix_table_double_lock(net, old_hash, new_hash); if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) goto out_spin; __unix_set_addr_hash(net, sk, addr, new_hash); unix_table_double_unlock(net, old_hash, new_hash); mutex_unlock(&u->bindlock); return 0; out_spin: unix_table_double_unlock(net, old_hash, new_hash); err = -EADDRINUSE; out_mutex: mutex_unlock(&u->bindlock); out: unix_release_addr(addr); return err; } static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) { struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; struct sock *sk = sock->sk; int err; if (addr_len == offsetof(struct sockaddr_un, sun_path) && sunaddr->sun_family == AF_UNIX) return unix_autobind(sk); err = unix_validate_addr(sunaddr, addr_len); if (err) return err; if (sunaddr->sun_path[0]) err = unix_bind_bsd(sk, sunaddr, addr_len); else err = unix_bind_abstract(sk, sunaddr, addr_len); 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) swap(sk1, sk2); unix_state_lock(sk1); unix_state_lock(sk2); } 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 sockaddr_un *sunaddr = (struct sockaddr_un *)addr; struct sock *sk = sock->sk; struct sock *other; int err; err = -EINVAL; if (alen < offsetofend(struct sockaddr, sa_family)) goto out; if (addr->sa_family != AF_UNSPEC) { err = unix_validate_addr(sunaddr, alen); if (err) goto out; err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, addr, &alen); if (err) goto out; if ((test_bit(SOCK_PASSCRED, &sock->flags) || test_bit(SOCK_PASSPIDFD, &sock->flags)) && !READ_ONCE(unix_sk(sk)->addr)) { err = unix_autobind(sk); if (err) goto out; } restart: other = unix_find_other(sock_net(sk), sunaddr, alen, sock->type); if (IS_ERR(other)) { err = PTR_ERR(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; WRITE_ONCE(sk->sk_state, TCP_ESTABLISHED); WRITE_ONCE(other->sk_state, TCP_ESTABLISHED); } 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; if (!other) WRITE_ONCE(sk->sk_state, TCP_CLOSE); 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); unix_state_lock(old_peer); if (!unix_peer(old_peer)) WRITE_ONCE(old_peer->sk_state, TCP_CLOSE); unix_state_unlock(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) __releases(&unix_sk(other)->lock) { 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_lockless(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, *newsk = NULL, *other = NULL; struct unix_sock *u = unix_sk(sk), *newu, *otheru; struct net *net = sock_net(sk); struct sk_buff *skb = NULL; unsigned char state; long timeo; int err; err = unix_validate_addr(sunaddr, addr_len); if (err) goto out; err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, uaddr, &addr_len); if (err) goto out; if ((test_bit(SOCK_PASSCRED, &sock->flags) || test_bit(SOCK_PASSPIDFD, &sock->flags)) && !READ_ONCE(u->addr)) { err = unix_autobind(sk); if (err) 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. */ /* create new sock for complete connection */ newsk = unix_create1(net, NULL, 0, sock->type); if (IS_ERR(newsk)) { err = PTR_ERR(newsk); newsk = NULL; goto out; } err = -ENOMEM; /* 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); if (IS_ERR(other)) { err = PTR_ERR(other); other = NULL; goto out; } 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_lockless(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; } /* self connect and simultaneous connect are eliminated * by rejecting TCP_LISTEN socket to avoid deadlock. */ state = READ_ONCE(sk->sk_state); if (unlikely(state != TCP_CLOSE)) { err = state == TCP_ESTABLISHED ? -EISCONN : -EINVAL; goto out_unlock; } unix_state_lock(sk); if (unlikely(sk->sk_state != TCP_CLOSE)) { err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EINVAL; unix_state_unlock(sk); goto out_unlock; } 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); newu->listener = other; 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 its lock. Insertion into the * hash chain we'd found it in had been done in an * earlier critical area protected by the chain's 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; WRITE_ONCE(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 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); 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_PASSPIDFD, &old->flags)) set_bit(SOCK_PASSPIDFD, &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, struct proto_accept_arg *arg) { struct sock *sk = sock->sk; struct sk_buff *skb; struct sock *tsk; arg->err = -EOPNOTSUPP; if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) goto out; arg->err = -EINVAL; if (READ_ONCE(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, (arg->flags & O_NONBLOCK) ? MSG_DONTWAIT : 0, &arg->err); if (!skb) { /* This means receive shutdown. */ if (arg->err == 0) arg->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); unix_update_edges(unix_sk(tsk)); newsock->state = SS_CONNECTED; unix_sock_inherit_flags(sock, newsock); sock_graft(tsk, newsock); unix_state_unlock(tsk); return 0; out: return arg->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 = offsetof(struct sockaddr_un, sun_path); } else { err = addr->len; memcpy(sunaddr, addr->name, addr->len); if (peer) BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err, CGROUP_UNIX_GETPEERNAME); else BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err, CGROUP_UNIX_GETSOCKNAME); } sock_put(sk); out: return err; } /* The "user->unix_inflight" variable is protected by the garbage * collection lock, and we just read it locklessly here. If you go * over the limit, there might be a tiny race in actually noticing * it across threads. Tough. */ static inline bool too_many_unix_fds(struct task_struct *p) { struct user_struct *user = current_user(); if (unlikely(READ_ONCE(user->unix_inflight) > task_rlimit(p, RLIMIT_NOFILE))) return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN); return false; } static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) { if (too_many_unix_fds(current)) return -ETOOMANYREFS; UNIXCB(skb).fp = scm->fp; scm->fp = NULL; if (unix_prepare_fpl(UNIXCB(skb).fp)) return -ENOMEM; return 0; } static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) { scm->fp = UNIXCB(skb).fp; UNIXCB(skb).fp = NULL; unix_destroy_fpl(scm->fp); } static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb) { scm->fp = scm_fp_dup(UNIXCB(skb).fp); } 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); } 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) || test_bit(SOCK_PASSPIDFD, &sock->flags) || !other->sk_socket || test_bit(SOCK_PASSCRED, &other->sk_socket->flags) || test_bit(SOCK_PASSPIDFD, &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 bool unix_skb_scm_eq(struct sk_buff *skb, struct scm_cookie *scm) { return UNIXCB(skb).pid == scm->pid && uid_eq(UNIXCB(skb).uid, scm->creds.uid) && gid_eq(UNIXCB(skb).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); if (unlikely(fp && fp->count)) { atomic_add(fp->count, &u->scm_stat.nr_fds); unix_add_edges(fp, u); } } 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); if (unlikely(fp && fp->count)) { atomic_sub(fp->count, &u->scm_stat.nr_fds); unix_del_edges(fp); } } /* * Send AF_UNIX data. */ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) { DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name); struct sock *sk = sock->sk, *other = NULL; struct unix_sock *u = unix_sk(sk); struct scm_cookie scm; struct sk_buff *skb; int data_len = 0; int sk_locked; long timeo; int err; err = scm_send(sock, msg, &scm, false); if (err < 0) return err; wait_for_unix_gc(scm.fp); err = -EOPNOTSUPP; if (msg->msg_flags&MSG_OOB) goto out; if (msg->msg_namelen) { err = unix_validate_addr(sunaddr, msg->msg_namelen); if (err) goto out; err = BPF_CGROUP_RUN_PROG_UNIX_SENDMSG_LOCK(sk, msg->msg_name, &msg->msg_namelen, NULL); if (err) goto out; } else { sunaddr = NULL; err = -ENOTCONN; other = unix_peer_get(sk); if (!other) goto out; } if ((test_bit(SOCK_PASSCRED, &sock->flags) || test_bit(SOCK_PASSPIDFD, &sock->flags)) && !READ_ONCE(u->addr)) { err = unix_autobind(sk); if (err) goto out; } err = -EMSGSIZE; if (len > READ_ONCE(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(sock_net(sk), sunaddr, msg->msg_namelen, sk->sk_type); if (IS_ERR(other)) { err = PTR_ERR(other); 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 (sk->sk_type == SOCK_SEQPACKET) { /* We are here only when racing with unix_release_sock() * is clearing @other. Never change state to TCP_CLOSE * unlike SOCK_DGRAM wants. */ unix_state_unlock(sk); err = -EPIPE; } else if (unix_peer(sk) == other) { unix_peer(sk) = NULL; unix_dgram_peer_wake_disconnect_wakeup(sk, other); WRITE_ONCE(sk->sk_state, TCP_CLOSE); 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); scm_stat_add(other, skb); skb_queue_tail(&other->sk_receive_queue, skb); unix_state_unlock(other); other->sk_data_ready(other); sock_put(other); scm_destroy(&scm); return len; out_unlock: if (sk_locked) unix_state_unlock(sk); unix_state_unlock(other); out_free: kfree_skb(skb); out: if (other) sock_put(other); scm_destroy(&scm); return err; } /* We use paged skbs for stream sockets, and limit occupancy to 32768 * bytes, and a minimum of a full page. */ #define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768)) #if IS_ENABLED(CONFIG_AF_UNIX_OOB) static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other, struct scm_cookie *scm, bool fds_sent) { struct unix_sock *ousk = unix_sk(other); struct sk_buff *skb; int err = 0; skb = sock_alloc_send_skb(sock->sk, 1, msg->msg_flags & MSG_DONTWAIT, &err); if (!skb) return err; err = unix_scm_to_skb(scm, skb, !fds_sent); if (err < 0) { kfree_skb(skb); return err; } skb_put(skb, 1); err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, 1); if (err) { kfree_skb(skb); return err; } unix_state_lock(other); if (sock_flag(other, SOCK_DEAD) || (other->sk_shutdown & RCV_SHUTDOWN)) { unix_state_unlock(other); kfree_skb(skb); return -EPIPE; } maybe_add_creds(skb, sock, other); skb_get(skb); scm_stat_add(other, skb); spin_lock(&other->sk_receive_queue.lock); if (ousk->oob_skb) consume_skb(ousk->oob_skb); WRITE_ONCE(ousk->oob_skb, skb); __skb_queue_tail(&other->sk_receive_queue, skb); spin_unlock(&other->sk_receive_queue.lock); sk_send_sigurg(other); unix_state_unlock(other); other->sk_data_ready(other); return err; } #endif 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; err = scm_send(sock, msg, &scm, false); if (err < 0) return err; wait_for_unix_gc(scm.fp); err = -EOPNOTSUPP; if (msg->msg_flags & MSG_OOB) { #if IS_ENABLED(CONFIG_AF_UNIX_OOB) if (len) len--; else #endif goto out_err; } if (msg->msg_namelen) { err = READ_ONCE(sk->sk_state) == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; goto out_err; } else { err = -ENOTCONN; other = unix_peer(sk); if (!other) goto out_err; } if (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN) goto pipe_err; while (sent < len) { size = len - sent; if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) { skb = sock_alloc_send_pskb(sk, 0, 0, msg->msg_flags & MSG_DONTWAIT, &err, 0); } else { /* Keep two messages in the pipe so it schedules better */ size = min_t(int, size, (READ_ONCE(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; if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) { err = skb_splice_from_iter(skb, &msg->msg_iter, size, sk->sk_allocation); if (err < 0) { kfree_skb(skb); goto out_err; } size = err; refcount_add(size, &sk->sk_wmem_alloc); } else { 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); scm_stat_add(other, skb); skb_queue_tail(&other->sk_receive_queue, skb); unix_state_unlock(other); other->sk_data_ready(other); sent += size; } #if IS_ENABLED(CONFIG_AF_UNIX_OOB) if (msg->msg_flags & MSG_OOB) { err = queue_oob(sock, msg, other, &scm, fds_sent); if (err) goto out_err; sent++; } #endif 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 (READ_ONCE(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 (READ_ONCE(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); } } int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, int flags) { struct scm_cookie scm; struct socket *sock = sk->sk_socket; 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, &skip, &err, &last); if (skb) { if (!(flags & MSG_PEEK)) scm_stat_del(sk, 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); BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk, msg->msg_name, &msg->msg_namelen); } 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) unix_peek_fds(&scm, skb); } err = (flags & MSG_TRUNC) ? skb->len - skip : size; scm_recv_unix(sock, msg, &scm, flags); out_free: skb_free_datagram(sk, skb); mutex_unlock(&u->iolock); out: return err; } static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int flags) { struct sock *sk = sock->sk; #ifdef CONFIG_BPF_SYSCALL const struct proto *prot = READ_ONCE(sk->sk_prot); if (prot != &unix_dgram_proto) return prot->recvmsg(sk, msg, size, flags, NULL); #endif return __unix_dgram_recvmsg(sk, msg, size, flags); } static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor) { struct unix_sock *u = unix_sk(sk); struct sk_buff *skb; int err; mutex_lock(&u->iolock); skb = skb_recv_datagram(sk, MSG_DONTWAIT, &err); mutex_unlock(&u->iolock); if (!skb) return err; return recv_actor(sk, skb); } /* * 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) { unsigned int state = TASK_INTERRUPTIBLE | freezable * TASK_FREEZABLE; struct sk_buff *tail; DEFINE_WAIT(wait); unix_state_lock(sk); for (;;) { prepare_to_wait(sk_sleep(sk), &wait, state); 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); 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; }; #if IS_ENABLED(CONFIG_AF_UNIX_OOB) static int unix_stream_recv_urg(struct unix_stream_read_state *state) { struct socket *sock = state->socket; struct sock *sk = sock->sk; struct unix_sock *u = unix_sk(sk); int chunk = 1; struct sk_buff *oob_skb; mutex_lock(&u->iolock); unix_state_lock(sk); spin_lock(&sk->sk_receive_queue.lock); if (sock_flag(sk, SOCK_URGINLINE) || !u->oob_skb) { spin_unlock(&sk->sk_receive_queue.lock); unix_state_unlock(sk); mutex_unlock(&u->iolock); return -EINVAL; } oob_skb = u->oob_skb; if (!(state->flags & MSG_PEEK)) WRITE_ONCE(u->oob_skb, NULL); else skb_get(oob_skb); spin_unlock(&sk->sk_receive_queue.lock); unix_state_unlock(sk); chunk = state->recv_actor(oob_skb, 0, chunk, state); if (!(state->flags & MSG_PEEK)) UNIXCB(oob_skb).consumed += 1; consume_skb(oob_skb); mutex_unlock(&u->iolock); if (chunk < 0) return -EFAULT; state->msg->msg_flags |= MSG_OOB; return 1; } static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk, int flags, int copied) { struct unix_sock *u = unix_sk(sk); if (!unix_skb_len(skb)) { struct sk_buff *unlinked_skb = NULL; spin_lock(&sk->sk_receive_queue.lock); if (copied && (!u->oob_skb || skb == u->oob_skb)) { skb = NULL; } else if (flags & MSG_PEEK) { skb = skb_peek_next(skb, &sk->sk_receive_queue); } else { unlinked_skb = skb; skb = skb_peek_next(skb, &sk->sk_receive_queue); __skb_unlink(unlinked_skb, &sk->sk_receive_queue); } spin_unlock(&sk->sk_receive_queue.lock); consume_skb(unlinked_skb); } else { struct sk_buff *unlinked_skb = NULL; spin_lock(&sk->sk_receive_queue.lock); if (skb == u->oob_skb) { if (copied) { skb = NULL; } else if (!(flags & MSG_PEEK)) { if (sock_flag(sk, SOCK_URGINLINE)) { WRITE_ONCE(u->oob_skb, NULL); consume_skb(skb); } else { __skb_unlink(skb, &sk->sk_receive_queue); WRITE_ONCE(u->oob_skb, NULL); unlinked_skb = skb; skb = skb_peek(&sk->sk_receive_queue); } } else if (!sock_flag(sk, SOCK_URGINLINE)) { skb = skb_peek_next(skb, &sk->sk_receive_queue); } } spin_unlock(&sk->sk_receive_queue.lock); if (unlinked_skb) { WARN_ON_ONCE(skb_unref(unlinked_skb)); kfree_skb(unlinked_skb); } } return skb; } #endif static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor) { struct unix_sock *u = unix_sk(sk); struct sk_buff *skb; int err; if (unlikely(READ_ONCE(sk->sk_state) != TCP_ESTABLISHED)) return -ENOTCONN; mutex_lock(&u->iolock); skb = skb_recv_datagram(sk, MSG_DONTWAIT, &err); mutex_unlock(&u->iolock); if (!skb) return err; #if IS_ENABLED(CONFIG_AF_UNIX_OOB) if (unlikely(skb == READ_ONCE(u->oob_skb))) { bool drop = false; unix_state_lock(sk); if (sock_flag(sk, SOCK_DEAD)) { unix_state_unlock(sk); kfree_skb(skb); return -ECONNRESET; } spin_lock(&sk->sk_receive_queue.lock); if (likely(skb == u->oob_skb)) { WRITE_ONCE(u->oob_skb, NULL); drop = true; } spin_unlock(&sk->sk_receive_queue.lock); unix_state_unlock(sk); if (drop) { WARN_ON_ONCE(skb_unref(skb)); kfree_skb(skb); return -EAGAIN; } } #endif return recv_actor(sk, skb); } 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(READ_ONCE(sk->sk_state) != TCP_ESTABLISHED)) { err = -EINVAL; goto out; } if (unlikely(flags & MSG_OOB)) { err = -EOPNOTSUPP; #if IS_ENABLED(CONFIG_AF_UNIX_OOB) err = unix_stream_recv_urg(state); #endif 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 { struct sk_buff *skb, *last; int chunk; 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 IS_ENABLED(CONFIG_AF_UNIX_OOB) if (skb) { skb = manage_oob(skb, sk, flags, copied); if (!skb && copied) { unix_state_unlock(sk); break; } } #endif 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) || test_bit(SOCK_PASSPIDFD, &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); BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk, state->msg->msg_name, &state->msg->msg_namelen); sunaddr = NULL; } chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size); chunk = state->recv_actor(skb, skip, chunk, state); if (chunk < 0) { 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) { scm_stat_del(sk, skb); 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) unix_peek_fds(&scm, skb); 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_unix(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; } int __unix_stream_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, int flags) { struct unix_stream_read_state state = { .recv_actor = unix_stream_read_actor, .socket = sk->sk_socket, .msg = msg, .size = size, .flags = flags }; return unix_stream_read_generic(&state, true); } 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 }; #ifdef CONFIG_BPF_SYSCALL struct sock *sk = sock->sk; const struct proto *prot = READ_ONCE(sk->sk_prot); if (prot != &unix_stream_proto) return prot->recvmsg(sk, msg, size, flags, NULL); #endif 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); WRITE_ONCE(sk->sk_shutdown, 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; const struct proto *prot = READ_ONCE(other->sk_prot); if (prot->unhash) prot->unhash(other); if (mode&RCV_SHUTDOWN) peer_mode |= SEND_SHUTDOWN; if (mode&SEND_SHUTDOWN) peer_mode |= RCV_SHUTDOWN; unix_state_lock(other); WRITE_ONCE(other->sk_shutdown, 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 (READ_ONCE(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; #if IS_ENABLED(CONFIG_AF_UNIX_OOB) case SIOCATMARK: { struct unix_sock *u = unix_sk(sk); struct sk_buff *skb; int answ = 0; mutex_lock(&u->iolock); skb = skb_peek(&sk->sk_receive_queue); if (skb) { struct sk_buff *oob_skb = READ_ONCE(u->oob_skb); if (skb == oob_skb || (!oob_skb && !unix_skb_len(skb))) answ = 1; } mutex_unlock(&u->iolock); err = put_user(answ, (int __user *)arg); } break; #endif 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; unsigned char state; __poll_t mask; u8 shutdown; sock_poll_wait(file, sock, wait); mask = 0; shutdown = READ_ONCE(sk->sk_shutdown); state = READ_ONCE(sk->sk_state); /* exceptional events? */ if (READ_ONCE(sk->sk_err)) mask |= EPOLLERR; if (shutdown == SHUTDOWN_MASK) mask |= EPOLLHUP; if (shutdown & RCV_SHUTDOWN) mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM; /* readable? */ if (!skb_queue_empty_lockless(&sk->sk_receive_queue)) mask |= EPOLLIN | EPOLLRDNORM; if (sk_is_readable(sk)) mask |= EPOLLIN | EPOLLRDNORM; #if IS_ENABLED(CONFIG_AF_UNIX_OOB) if (READ_ONCE(unix_sk(sk)->oob_skb)) mask |= EPOLLPRI; #endif /* Connection-based need to check for termination and startup */ if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && 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, state)) 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; unsigned char state; __poll_t mask; u8 shutdown; sock_poll_wait(file, sock, wait); mask = 0; shutdown = READ_ONCE(sk->sk_shutdown); state = READ_ONCE(sk->sk_state); /* exceptional events? */ if (READ_ONCE(sk->sk_err) || !skb_queue_empty_lockless(&sk->sk_error_queue)) mask |= EPOLLERR | (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0); if (shutdown & RCV_SHUTDOWN) mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM; if (shutdown == SHUTDOWN_MASK) mask |= EPOLLHUP; /* readable? */ if (!skb_queue_empty_lockless(&sk->sk_receive_queue)) mask |= EPOLLIN | EPOLLRDNORM; if (sk_is_readable(sk)) mask |= EPOLLIN | EPOLLRDNORM; /* Connection-based need to check for termination and startup */ if (sk->sk_type == SOCK_SEQPACKET && state == TCP_CLOSE) mask |= EPOLLHUP; /* No write status requested, avoid expensive OUT tests. */ if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT))) return mask; writable = unix_writable(sk, state); if (writable) { unix_state_lock(sk); other = unix_peer(sk); if (other && unix_peer(other) != sk && unix_recvq_full_lockless(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) & ((1UL << 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); unsigned long count = 0; struct sock *sk; for (sk = sk_head(&seq_file_net(seq)->unx.table.buckets[bucket]); sk; sk = sk_next(sk)) { if (++count == offset) break; } return sk; } static struct sock *unix_get_first(struct seq_file *seq, loff_t *pos) { unsigned long bucket = get_bucket(*pos); struct net *net = seq_file_net(seq); struct sock *sk; while (bucket < UNIX_HASH_SIZE) { spin_lock(&net->unx.table.locks[bucket]); sk = unix_from_bucket(seq, pos); if (sk) return sk; spin_unlock(&net->unx.table.locks[bucket]); *pos = set_bucket_offset(++bucket, 1); } return NULL; } static struct sock *unix_get_next(struct seq_file *seq, struct sock *sk, loff_t *pos) { unsigned long bucket = get_bucket(*pos); sk = sk_next(sk); if (sk) return sk; spin_unlock(&seq_file_net(seq)->unx.table.locks[bucket]); *pos = set_bucket_offset(++bucket, 1); return unix_get_first(seq, pos); } static void *unix_seq_start(struct seq_file *seq, loff_t *pos) { if (!*pos) return SEQ_START_TOKEN; return unix_get_first(seq, pos); } static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) { ++*pos; if (v == SEQ_START_TOKEN) return unix_get_first(seq, pos); return unix_get_next(seq, v, pos); } static void unix_seq_stop(struct seq_file *seq, void *v) { struct sock *sk = v; if (sk) spin_unlock(&seq_file_net(seq)->unx.table.locks[sk->sk_hash]); } 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 a hash table lock here int i, len; seq_putc(seq, ' '); i = 0; len = u->addr->len - offsetof(struct sockaddr_un, sun_path); if (u->addr->name->sun_path[0]) { 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, }; #ifdef CONFIG_BPF_SYSCALL struct bpf_unix_iter_state { struct seq_net_private p; unsigned int cur_sk; unsigned int end_sk; unsigned int max_sk; struct sock **batch; bool st_bucket_done; }; struct bpf_iter__unix { __bpf_md_ptr(struct bpf_iter_meta *, meta); __bpf_md_ptr(struct unix_sock *, unix_sk); uid_t uid __aligned(8); }; static int unix_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta, struct unix_sock *unix_sk, uid_t uid) { struct bpf_iter__unix ctx; meta->seq_num--; /* skip SEQ_START_TOKEN */ ctx.meta = meta; ctx.unix_sk = unix_sk; ctx.uid = uid; return bpf_iter_run_prog(prog, &ctx); } static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk) { struct bpf_unix_iter_state *iter = seq->private; unsigned int expected = 1; struct sock *sk; sock_hold(start_sk); iter->batch[iter->end_sk++] = start_sk; for (sk = sk_next(start_sk); sk; sk = sk_next(sk)) { if (iter->end_sk < iter->max_sk) { sock_hold(sk); iter->batch[iter->end_sk++] = sk; } expected++; } spin_unlock(&seq_file_net(seq)->unx.table.locks[start_sk->sk_hash]); return expected; } static void bpf_iter_unix_put_batch(struct bpf_unix_iter_state *iter) { while (iter->cur_sk < iter->end_sk) sock_put(iter->batch[iter->cur_sk++]); } static int bpf_iter_unix_realloc_batch(struct bpf_unix_iter_state *iter, unsigned int new_batch_sz) { struct sock **new_batch; new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz, GFP_USER | __GFP_NOWARN); if (!new_batch) return -ENOMEM; bpf_iter_unix_put_batch(iter); kvfree(iter->batch); iter->batch = new_batch; iter->max_sk = new_batch_sz; return 0; } static struct sock *bpf_iter_unix_batch(struct seq_file *seq, loff_t *pos) { struct bpf_unix_iter_state *iter = seq->private; unsigned int expected; bool resized = false; struct sock *sk; if (iter->st_bucket_done) *pos = set_bucket_offset(get_bucket(*pos) + 1, 1); again: /* Get a new batch */ iter->cur_sk = 0; iter->end_sk = 0; sk = unix_get_first(seq, pos); if (!sk) return NULL; /* Done */ expected = bpf_iter_unix_hold_batch(seq, sk); if (iter->end_sk == expected) { iter->st_bucket_done = true; return sk; } if (!resized && !bpf_iter_unix_realloc_batch(iter, expected * 3 / 2)) { resized = true; goto again; } return sk; } static void *bpf_iter_unix_seq_start(struct seq_file *seq, loff_t *pos) { if (!*pos) return SEQ_START_TOKEN; /* bpf iter does not support lseek, so it always * continue from where it was stop()-ped. */ return bpf_iter_unix_batch(seq, pos); } static void *bpf_iter_unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) { struct bpf_unix_iter_state *iter = seq->private; struct sock *sk; /* Whenever seq_next() is called, the iter->cur_sk is * done with seq_show(), so advance to the next sk in * the batch. */ if (iter->cur_sk < iter->end_sk) sock_put(iter->batch[iter->cur_sk++]); ++*pos; if (iter->cur_sk < iter->end_sk) sk = iter->batch[iter->cur_sk]; else sk = bpf_iter_unix_batch(seq, pos); return sk; } static int bpf_iter_unix_seq_show(struct seq_file *seq, void *v) { struct bpf_iter_meta meta; struct bpf_prog *prog; struct sock *sk = v; uid_t uid; bool slow; int ret; if (v == SEQ_START_TOKEN) return 0; slow = lock_sock_fast(sk); if (unlikely(sk_unhashed(sk))) { ret = SEQ_SKIP; goto unlock; } uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)); meta.seq = seq; prog = bpf_iter_get_info(&meta, false); ret = unix_prog_seq_show(prog, &meta, v, uid); unlock: unlock_sock_fast(sk, slow); return ret; } static void bpf_iter_unix_seq_stop(struct seq_file *seq, void *v) { struct bpf_unix_iter_state *iter = seq->private; struct bpf_iter_meta meta; struct bpf_prog *prog; if (!v) { meta.seq = seq; prog = bpf_iter_get_info(&meta, true); if (prog) (void)unix_prog_seq_show(prog, &meta, v, 0); } if (iter->cur_sk < iter->end_sk) bpf_iter_unix_put_batch(iter); } static const struct seq_operations bpf_iter_unix_seq_ops = { .start = bpf_iter_unix_seq_start, .next = bpf_iter_unix_seq_next, .stop = bpf_iter_unix_seq_stop, .show = bpf_iter_unix_seq_show, }; #endif #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 i; 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))) goto err_sysctl; #endif net->unx.table.locks = kvmalloc_array(UNIX_HASH_SIZE, sizeof(spinlock_t), GFP_KERNEL); if (!net->unx.table.locks) goto err_proc; net->unx.table.buckets = kvmalloc_array(UNIX_HASH_SIZE, sizeof(struct hlist_head), GFP_KERNEL); if (!net->unx.table.buckets) goto free_locks; for (i = 0; i < UNIX_HASH_SIZE; i++) { spin_lock_init(&net->unx.table.locks[i]); lock_set_cmp_fn(&net->unx.table.locks[i], unix_table_lock_cmp_fn, NULL); INIT_HLIST_HEAD(&net->unx.table.buckets[i]); } return 0; free_locks: kvfree(net->unx.table.locks); err_proc: #ifdef CONFIG_PROC_FS remove_proc_entry("unix", net->proc_net); err_sysctl: #endif unix_sysctl_unregister(net); out: return -ENOMEM; } static void __net_exit unix_net_exit(struct net *net) { kvfree(net->unx.table.buckets); kvfree(net->unx.table.locks); 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, }; #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) DEFINE_BPF_ITER_FUNC(unix, struct bpf_iter_meta *meta, struct unix_sock *unix_sk, uid_t uid) #define INIT_BATCH_SZ 16 static int bpf_iter_init_unix(void *priv_data, struct bpf_iter_aux_info *aux) { struct bpf_unix_iter_state *iter = priv_data; int err; err = bpf_iter_init_seq_net(priv_data, aux); if (err) return err; err = bpf_iter_unix_realloc_batch(iter, INIT_BATCH_SZ); if (err) { bpf_iter_fini_seq_net(priv_data); return err; } return 0; } static void bpf_iter_fini_unix(void *priv_data) { struct bpf_unix_iter_state *iter = priv_data; bpf_iter_fini_seq_net(priv_data); kvfree(iter->batch); } static const struct bpf_iter_seq_info unix_seq_info = { .seq_ops = &bpf_iter_unix_seq_ops, .init_seq_private = bpf_iter_init_unix, .fini_seq_private = bpf_iter_fini_unix, .seq_priv_size = sizeof(struct bpf_unix_iter_state), }; static const struct bpf_func_proto * bpf_iter_unix_get_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_setsockopt: return &bpf_sk_setsockopt_proto; case BPF_FUNC_getsockopt: return &bpf_sk_getsockopt_proto; default: return NULL; } } static struct bpf_iter_reg unix_reg_info = { .target = "unix", .ctx_arg_info_size = 1, .ctx_arg_info = { { offsetof(struct bpf_iter__unix, unix_sk), PTR_TO_BTF_ID_OR_NULL }, }, .get_func_proto = bpf_iter_unix_get_func_proto, .seq_info = &unix_seq_info, }; static void __init bpf_iter_register(void) { unix_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UNIX]; if (bpf_iter_reg_target(&unix_reg_info)) pr_warn("Warning: could not register bpf iterator unix\n"); } #endif static int __init af_unix_init(void) { int i, rc = -1; BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb)); for (i = 0; i < UNIX_HASH_SIZE / 2; i++) { spin_lock_init(&bsd_socket_locks[i]); INIT_HLIST_HEAD(&bsd_socket_buckets[i]); } rc = proto_register(&unix_dgram_proto, 1); if (rc != 0) { pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__); goto out; } rc = proto_register(&unix_stream_proto, 1); if (rc != 0) { pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__); proto_unregister(&unix_dgram_proto); goto out; } sock_register(&unix_family_ops); register_pernet_subsys(&unix_net_ops); unix_bpf_build_proto(); #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) bpf_iter_register(); #endif out: return rc; } /* Later than subsys_initcall() because we depend on stuff initialised there */ fs_initcall(af_unix_init);
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