| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | /* |
| 3 | * NET4: Implementation of BSD Unix domain sockets. |
| 4 | * |
| 5 | * Authors: Alan Cox, <alan@lxorguk.ukuu.org.uk> |
| 6 | * |
| 7 | * Fixes: |
| 8 | * Linus Torvalds : Assorted bug cures. |
| 9 | * Niibe Yutaka : async I/O support. |
| 10 | * Carsten Paeth : PF_UNIX check, address fixes. |
| 11 | * Alan Cox : Limit size of allocated blocks. |
| 12 | * Alan Cox : Fixed the stupid socketpair bug. |
| 13 | * Alan Cox : BSD compatibility fine tuning. |
| 14 | * Alan Cox : Fixed a bug in connect when interrupted. |
| 15 | * Alan Cox : Sorted out a proper draft version of |
| 16 | * file descriptor passing hacked up from |
| 17 | * Mike Shaver's work. |
| 18 | * Marty Leisner : Fixes to fd passing |
| 19 | * Nick Nevin : recvmsg bugfix. |
| 20 | * Alan Cox : Started proper garbage collector |
| 21 | * Heiko EiBfeldt : Missing verify_area check |
| 22 | * Alan Cox : Started POSIXisms |
| 23 | * Andreas Schwab : Replace inode by dentry for proper |
| 24 | * reference counting |
| 25 | * Kirk Petersen : Made this a module |
| 26 | * Christoph Rohland : Elegant non-blocking accept/connect algorithm. |
| 27 | * Lots of bug fixes. |
| 28 | * Alexey Kuznetosv : Repaired (I hope) bugs introduces |
| 29 | * by above two patches. |
| 30 | * Andrea Arcangeli : If possible we block in connect(2) |
| 31 | * if the max backlog of the listen socket |
| 32 | * is been reached. This won't break |
| 33 | * old apps and it will avoid huge amount |
| 34 | * of socks hashed (this for unix_gc() |
| 35 | * performances reasons). |
| 36 | * Security fix that limits the max |
| 37 | * number of socks to 2*max_files and |
| 38 | * the number of skb queueable in the |
| 39 | * dgram receiver. |
| 40 | * Artur Skawina : Hash function optimizations |
| 41 | * Alexey Kuznetsov : Full scale SMP. Lot of bugs are introduced 8) |
| 42 | * Malcolm Beattie : Set peercred for socketpair |
| 43 | * Michal Ostrowski : Module initialization cleanup. |
| 44 | * Arnaldo C. Melo : Remove MOD_{INC,DEC}_USE_COUNT, |
| 45 | * the core infrastructure is doing that |
| 46 | * for all net proto families now (2.5.69+) |
| 47 | * |
| 48 | * Known differences from reference BSD that was tested: |
| 49 | * |
| 50 | * [TO FIX] |
| 51 | * ECONNREFUSED is not returned from one end of a connected() socket to the |
| 52 | * other the moment one end closes. |
| 53 | * fstat() doesn't return st_dev=0, and give the blksize as high water mark |
| 54 | * and a fake inode identifier (nor the BSD first socket fstat twice bug). |
| 55 | * [NOT TO FIX] |
| 56 | * accept() returns a path name even if the connecting socket has closed |
| 57 | * in the meantime (BSD loses the path and gives up). |
| 58 | * accept() returns 0 length path for an unbound connector. BSD returns 16 |
| 59 | * and a null first byte in the path (but not for gethost/peername - BSD bug ??) |
| 60 | * socketpair(...SOCK_RAW..) doesn't panic the kernel. |
| 61 | * BSD af_unix apparently has connect forgetting to block properly. |
| 62 | * (need to check this with the POSIX spec in detail) |
| 63 | * |
| 64 | * Differences from 2.0.0-11-... (ANK) |
| 65 | * Bug fixes and improvements. |
| 66 | * - client shutdown killed server socket. |
| 67 | * - removed all useless cli/sti pairs. |
| 68 | * |
| 69 | * Semantic changes/extensions. |
| 70 | * - generic control message passing. |
| 71 | * - SCM_CREDENTIALS control message. |
| 72 | * - "Abstract" (not FS based) socket bindings. |
| 73 | * Abstract names are sequences of bytes (not zero terminated) |
| 74 | * started by 0, so that this name space does not intersect |
| 75 | * with BSD names. |
| 76 | */ |
| 77 | |
| 78 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 79 | |
| 80 | #include <linux/module.h> |
| 81 | #include <linux/kernel.h> |
| 82 | #include <linux/signal.h> |
| 83 | #include <linux/sched/signal.h> |
| 84 | #include <linux/errno.h> |
| 85 | #include <linux/string.h> |
| 86 | #include <linux/stat.h> |
| 87 | #include <linux/dcache.h> |
| 88 | #include <linux/namei.h> |
| 89 | #include <linux/socket.h> |
| 90 | #include <linux/un.h> |
| 91 | #include <linux/fcntl.h> |
| 92 | #include <linux/filter.h> |
| 93 | #include <linux/termios.h> |
| 94 | #include <linux/sockios.h> |
| 95 | #include <linux/net.h> |
| 96 | #include <linux/in.h> |
| 97 | #include <linux/fs.h> |
| 98 | #include <linux/slab.h> |
| 99 | #include <linux/uaccess.h> |
| 100 | #include <linux/skbuff.h> |
| 101 | #include <linux/netdevice.h> |
| 102 | #include <net/net_namespace.h> |
| 103 | #include <net/sock.h> |
| 104 | #include <net/tcp_states.h> |
| 105 | #include <net/af_unix.h> |
| 106 | #include <linux/proc_fs.h> |
| 107 | #include <linux/seq_file.h> |
| 108 | #include <net/scm.h> |
| 109 | #include <linux/init.h> |
| 110 | #include <linux/poll.h> |
| 111 | #include <linux/rtnetlink.h> |
| 112 | #include <linux/mount.h> |
| 113 | #include <net/checksum.h> |
| 114 | #include <linux/security.h> |
| 115 | #include <linux/splice.h> |
| 116 | #include <linux/freezer.h> |
| 117 | #include <linux/file.h> |
| 118 | #include <linux/btf_ids.h> |
| 119 | #include <linux/bpf-cgroup.h> |
| 120 | |
| 121 | #include "scm.h" |
| 122 | |
| 123 | static atomic_long_t unix_nr_socks; |
| 124 | static struct hlist_head bsd_socket_buckets[UNIX_HASH_SIZE / 2]; |
| 125 | static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2]; |
| 126 | |
| 127 | /* SMP locking strategy: |
| 128 | * hash table is protected with spinlock. |
| 129 | * each socket state is protected by separate spinlock. |
| 130 | */ |
| 131 | |
| 132 | static unsigned int unix_unbound_hash(struct sock *sk) |
| 133 | { |
| 134 | unsigned long hash = (unsigned long)sk; |
| 135 | |
| 136 | hash ^= hash >> 16; |
| 137 | hash ^= hash >> 8; |
| 138 | hash ^= sk->sk_type; |
| 139 | |
| 140 | return hash & UNIX_HASH_MOD; |
| 141 | } |
| 142 | |
| 143 | static unsigned int unix_bsd_hash(struct inode *i) |
| 144 | { |
| 145 | return i->i_ino & UNIX_HASH_MOD; |
| 146 | } |
| 147 | |
| 148 | static unsigned int unix_abstract_hash(struct sockaddr_un *sunaddr, |
| 149 | int addr_len, int type) |
| 150 | { |
| 151 | __wsum csum = csum_partial(sunaddr, addr_len, 0); |
| 152 | unsigned int hash; |
| 153 | |
| 154 | hash = (__force unsigned int)csum_fold(csum); |
| 155 | hash ^= hash >> 8; |
| 156 | hash ^= type; |
| 157 | |
| 158 | return UNIX_HASH_MOD + 1 + (hash & UNIX_HASH_MOD); |
| 159 | } |
| 160 | |
| 161 | static void unix_table_double_lock(struct net *net, |
| 162 | unsigned int hash1, unsigned int hash2) |
| 163 | { |
| 164 | if (hash1 == hash2) { |
| 165 | spin_lock(&net->unx.table.locks[hash1]); |
| 166 | return; |
| 167 | } |
| 168 | |
| 169 | if (hash1 > hash2) |
| 170 | swap(hash1, hash2); |
| 171 | |
| 172 | spin_lock(&net->unx.table.locks[hash1]); |
| 173 | spin_lock_nested(&net->unx.table.locks[hash2], SINGLE_DEPTH_NESTING); |
| 174 | } |
| 175 | |
| 176 | static void unix_table_double_unlock(struct net *net, |
| 177 | unsigned int hash1, unsigned int hash2) |
| 178 | { |
| 179 | if (hash1 == hash2) { |
| 180 | spin_unlock(&net->unx.table.locks[hash1]); |
| 181 | return; |
| 182 | } |
| 183 | |
| 184 | spin_unlock(&net->unx.table.locks[hash1]); |
| 185 | spin_unlock(&net->unx.table.locks[hash2]); |
| 186 | } |
| 187 | |
| 188 | #ifdef CONFIG_SECURITY_NETWORK |
| 189 | static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) |
| 190 | { |
| 191 | UNIXCB(skb).secid = scm->secid; |
| 192 | } |
| 193 | |
| 194 | static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) |
| 195 | { |
| 196 | scm->secid = UNIXCB(skb).secid; |
| 197 | } |
| 198 | |
| 199 | static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb) |
| 200 | { |
| 201 | return (scm->secid == UNIXCB(skb).secid); |
| 202 | } |
| 203 | #else |
| 204 | static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb) |
| 205 | { } |
| 206 | |
| 207 | static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb) |
| 208 | { } |
| 209 | |
| 210 | static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb) |
| 211 | { |
| 212 | return true; |
| 213 | } |
| 214 | #endif /* CONFIG_SECURITY_NETWORK */ |
| 215 | |
| 216 | static inline int unix_our_peer(struct sock *sk, struct sock *osk) |
| 217 | { |
| 218 | return unix_peer(osk) == sk; |
| 219 | } |
| 220 | |
| 221 | static inline int unix_may_send(struct sock *sk, struct sock *osk) |
| 222 | { |
| 223 | return unix_peer(osk) == NULL || unix_our_peer(sk, osk); |
| 224 | } |
| 225 | |
| 226 | static inline int unix_recvq_full(const struct sock *sk) |
| 227 | { |
| 228 | return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog; |
| 229 | } |
| 230 | |
| 231 | static inline int unix_recvq_full_lockless(const struct sock *sk) |
| 232 | { |
| 233 | return skb_queue_len_lockless(&sk->sk_receive_queue) > |
| 234 | READ_ONCE(sk->sk_max_ack_backlog); |
| 235 | } |
| 236 | |
| 237 | struct sock *unix_peer_get(struct sock *s) |
| 238 | { |
| 239 | struct sock *peer; |
| 240 | |
| 241 | unix_state_lock(s); |
| 242 | peer = unix_peer(s); |
| 243 | if (peer) |
| 244 | sock_hold(peer); |
| 245 | unix_state_unlock(s); |
| 246 | return peer; |
| 247 | } |
| 248 | EXPORT_SYMBOL_GPL(unix_peer_get); |
| 249 | |
| 250 | static struct unix_address *unix_create_addr(struct sockaddr_un *sunaddr, |
| 251 | int addr_len) |
| 252 | { |
| 253 | struct unix_address *addr; |
| 254 | |
| 255 | addr = kmalloc(sizeof(*addr) + addr_len, GFP_KERNEL); |
| 256 | if (!addr) |
| 257 | return NULL; |
| 258 | |
| 259 | refcount_set(&addr->refcnt, 1); |
| 260 | addr->len = addr_len; |
| 261 | memcpy(addr->name, sunaddr, addr_len); |
| 262 | |
| 263 | return addr; |
| 264 | } |
| 265 | |
| 266 | static inline void unix_release_addr(struct unix_address *addr) |
| 267 | { |
| 268 | if (refcount_dec_and_test(&addr->refcnt)) |
| 269 | kfree(addr); |
| 270 | } |
| 271 | |
| 272 | /* |
| 273 | * Check unix socket name: |
| 274 | * - should be not zero length. |
| 275 | * - if started by not zero, should be NULL terminated (FS object) |
| 276 | * - if started by zero, it is abstract name. |
| 277 | */ |
| 278 | |
| 279 | static int unix_validate_addr(struct sockaddr_un *sunaddr, int addr_len) |
| 280 | { |
| 281 | if (addr_len <= offsetof(struct sockaddr_un, sun_path) || |
| 282 | addr_len > sizeof(*sunaddr)) |
| 283 | return -EINVAL; |
| 284 | |
| 285 | if (sunaddr->sun_family != AF_UNIX) |
| 286 | return -EINVAL; |
| 287 | |
| 288 | return 0; |
| 289 | } |
| 290 | |
| 291 | static int unix_mkname_bsd(struct sockaddr_un *sunaddr, int addr_len) |
| 292 | { |
| 293 | struct sockaddr_storage *addr = (struct sockaddr_storage *)sunaddr; |
| 294 | short offset = offsetof(struct sockaddr_storage, __data); |
| 295 | |
| 296 | BUILD_BUG_ON(offset != offsetof(struct sockaddr_un, sun_path)); |
| 297 | |
| 298 | /* This may look like an off by one error but it is a bit more |
| 299 | * subtle. 108 is the longest valid AF_UNIX path for a binding. |
| 300 | * sun_path[108] doesn't as such exist. However in kernel space |
| 301 | * we are guaranteed that it is a valid memory location in our |
| 302 | * kernel address buffer because syscall functions always pass |
| 303 | * a pointer of struct sockaddr_storage which has a bigger buffer |
| 304 | * than 108. Also, we must terminate sun_path for strlen() in |
| 305 | * getname_kernel(). |
| 306 | */ |
| 307 | addr->__data[addr_len - offset] = 0; |
| 308 | |
| 309 | /* Don't pass sunaddr->sun_path to strlen(). Otherwise, 108 will |
| 310 | * cause panic if CONFIG_FORTIFY_SOURCE=y. Let __fortify_strlen() |
| 311 | * know the actual buffer. |
| 312 | */ |
| 313 | return strlen(addr->__data) + offset + 1; |
| 314 | } |
| 315 | |
| 316 | static void __unix_remove_socket(struct sock *sk) |
| 317 | { |
| 318 | sk_del_node_init(sk); |
| 319 | } |
| 320 | |
| 321 | static void __unix_insert_socket(struct net *net, struct sock *sk) |
| 322 | { |
| 323 | DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk)); |
| 324 | sk_add_node(sk, &net->unx.table.buckets[sk->sk_hash]); |
| 325 | } |
| 326 | |
| 327 | static void __unix_set_addr_hash(struct net *net, struct sock *sk, |
| 328 | struct unix_address *addr, unsigned int hash) |
| 329 | { |
| 330 | __unix_remove_socket(sk); |
| 331 | smp_store_release(&unix_sk(sk)->addr, addr); |
| 332 | |
| 333 | sk->sk_hash = hash; |
| 334 | __unix_insert_socket(net, sk); |
| 335 | } |
| 336 | |
| 337 | static void unix_remove_socket(struct net *net, struct sock *sk) |
| 338 | { |
| 339 | spin_lock(&net->unx.table.locks[sk->sk_hash]); |
| 340 | __unix_remove_socket(sk); |
| 341 | spin_unlock(&net->unx.table.locks[sk->sk_hash]); |
| 342 | } |
| 343 | |
| 344 | static void unix_insert_unbound_socket(struct net *net, struct sock *sk) |
| 345 | { |
| 346 | spin_lock(&net->unx.table.locks[sk->sk_hash]); |
| 347 | __unix_insert_socket(net, sk); |
| 348 | spin_unlock(&net->unx.table.locks[sk->sk_hash]); |
| 349 | } |
| 350 | |
| 351 | static void unix_insert_bsd_socket(struct sock *sk) |
| 352 | { |
| 353 | spin_lock(&bsd_socket_locks[sk->sk_hash]); |
| 354 | sk_add_bind_node(sk, &bsd_socket_buckets[sk->sk_hash]); |
| 355 | spin_unlock(&bsd_socket_locks[sk->sk_hash]); |
| 356 | } |
| 357 | |
| 358 | static void unix_remove_bsd_socket(struct sock *sk) |
| 359 | { |
| 360 | if (!hlist_unhashed(&sk->sk_bind_node)) { |
| 361 | spin_lock(&bsd_socket_locks[sk->sk_hash]); |
| 362 | __sk_del_bind_node(sk); |
| 363 | spin_unlock(&bsd_socket_locks[sk->sk_hash]); |
| 364 | |
| 365 | sk_node_init(&sk->sk_bind_node); |
| 366 | } |
| 367 | } |
| 368 | |
| 369 | static struct sock *__unix_find_socket_byname(struct net *net, |
| 370 | struct sockaddr_un *sunname, |
| 371 | int len, unsigned int hash) |
| 372 | { |
| 373 | struct sock *s; |
| 374 | |
| 375 | sk_for_each(s, &net->unx.table.buckets[hash]) { |
| 376 | struct unix_sock *u = unix_sk(s); |
| 377 | |
| 378 | if (u->addr->len == len && |
| 379 | !memcmp(u->addr->name, sunname, len)) |
| 380 | return s; |
| 381 | } |
| 382 | return NULL; |
| 383 | } |
| 384 | |
| 385 | static inline struct sock *unix_find_socket_byname(struct net *net, |
| 386 | struct sockaddr_un *sunname, |
| 387 | int len, unsigned int hash) |
| 388 | { |
| 389 | struct sock *s; |
| 390 | |
| 391 | spin_lock(&net->unx.table.locks[hash]); |
| 392 | s = __unix_find_socket_byname(net, sunname, len, hash); |
| 393 | if (s) |
| 394 | sock_hold(s); |
| 395 | spin_unlock(&net->unx.table.locks[hash]); |
| 396 | return s; |
| 397 | } |
| 398 | |
| 399 | static struct sock *unix_find_socket_byinode(struct inode *i) |
| 400 | { |
| 401 | unsigned int hash = unix_bsd_hash(i); |
| 402 | struct sock *s; |
| 403 | |
| 404 | spin_lock(&bsd_socket_locks[hash]); |
| 405 | sk_for_each_bound(s, &bsd_socket_buckets[hash]) { |
| 406 | struct dentry *dentry = unix_sk(s)->path.dentry; |
| 407 | |
| 408 | if (dentry && d_backing_inode(dentry) == i) { |
| 409 | sock_hold(s); |
| 410 | spin_unlock(&bsd_socket_locks[hash]); |
| 411 | return s; |
| 412 | } |
| 413 | } |
| 414 | spin_unlock(&bsd_socket_locks[hash]); |
| 415 | return NULL; |
| 416 | } |
| 417 | |
| 418 | /* Support code for asymmetrically connected dgram sockets |
| 419 | * |
| 420 | * If a datagram socket is connected to a socket not itself connected |
| 421 | * to the first socket (eg, /dev/log), clients may only enqueue more |
| 422 | * messages if the present receive queue of the server socket is not |
| 423 | * "too large". This means there's a second writeability condition |
| 424 | * poll and sendmsg need to test. The dgram recv code will do a wake |
| 425 | * up on the peer_wait wait queue of a socket upon reception of a |
| 426 | * datagram which needs to be propagated to sleeping would-be writers |
| 427 | * since these might not have sent anything so far. This can't be |
| 428 | * accomplished via poll_wait because the lifetime of the server |
| 429 | * socket might be less than that of its clients if these break their |
| 430 | * association with it or if the server socket is closed while clients |
| 431 | * are still connected to it and there's no way to inform "a polling |
| 432 | * implementation" that it should let go of a certain wait queue |
| 433 | * |
| 434 | * In order to propagate a wake up, a wait_queue_entry_t of the client |
| 435 | * socket is enqueued on the peer_wait queue of the server socket |
| 436 | * whose wake function does a wake_up on the ordinary client socket |
| 437 | * wait queue. This connection is established whenever a write (or |
| 438 | * poll for write) hit the flow control condition and broken when the |
| 439 | * association to the server socket is dissolved or after a wake up |
| 440 | * was relayed. |
| 441 | */ |
| 442 | |
| 443 | static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int flags, |
| 444 | void *key) |
| 445 | { |
| 446 | struct unix_sock *u; |
| 447 | wait_queue_head_t *u_sleep; |
| 448 | |
| 449 | u = container_of(q, struct unix_sock, peer_wake); |
| 450 | |
| 451 | __remove_wait_queue(&unix_sk(u->peer_wake.private)->peer_wait, |
| 452 | q); |
| 453 | u->peer_wake.private = NULL; |
| 454 | |
| 455 | /* relaying can only happen while the wq still exists */ |
| 456 | u_sleep = sk_sleep(&u->sk); |
| 457 | if (u_sleep) |
| 458 | wake_up_interruptible_poll(u_sleep, key_to_poll(key)); |
| 459 | |
| 460 | return 0; |
| 461 | } |
| 462 | |
| 463 | static int unix_dgram_peer_wake_connect(struct sock *sk, struct sock *other) |
| 464 | { |
| 465 | struct unix_sock *u, *u_other; |
| 466 | int rc; |
| 467 | |
| 468 | u = unix_sk(sk); |
| 469 | u_other = unix_sk(other); |
| 470 | rc = 0; |
| 471 | spin_lock(&u_other->peer_wait.lock); |
| 472 | |
| 473 | if (!u->peer_wake.private) { |
| 474 | u->peer_wake.private = other; |
| 475 | __add_wait_queue(&u_other->peer_wait, &u->peer_wake); |
| 476 | |
| 477 | rc = 1; |
| 478 | } |
| 479 | |
| 480 | spin_unlock(&u_other->peer_wait.lock); |
| 481 | return rc; |
| 482 | } |
| 483 | |
| 484 | static void unix_dgram_peer_wake_disconnect(struct sock *sk, |
| 485 | struct sock *other) |
| 486 | { |
| 487 | struct unix_sock *u, *u_other; |
| 488 | |
| 489 | u = unix_sk(sk); |
| 490 | u_other = unix_sk(other); |
| 491 | spin_lock(&u_other->peer_wait.lock); |
| 492 | |
| 493 | if (u->peer_wake.private == other) { |
| 494 | __remove_wait_queue(&u_other->peer_wait, &u->peer_wake); |
| 495 | u->peer_wake.private = NULL; |
| 496 | } |
| 497 | |
| 498 | spin_unlock(&u_other->peer_wait.lock); |
| 499 | } |
| 500 | |
| 501 | static void unix_dgram_peer_wake_disconnect_wakeup(struct sock *sk, |
| 502 | struct sock *other) |
| 503 | { |
| 504 | unix_dgram_peer_wake_disconnect(sk, other); |
| 505 | wake_up_interruptible_poll(sk_sleep(sk), |
| 506 | EPOLLOUT | |
| 507 | EPOLLWRNORM | |
| 508 | EPOLLWRBAND); |
| 509 | } |
| 510 | |
| 511 | /* preconditions: |
| 512 | * - unix_peer(sk) == other |
| 513 | * - association is stable |
| 514 | */ |
| 515 | static int unix_dgram_peer_wake_me(struct sock *sk, struct sock *other) |
| 516 | { |
| 517 | int connected; |
| 518 | |
| 519 | connected = unix_dgram_peer_wake_connect(sk, other); |
| 520 | |
| 521 | /* If other is SOCK_DEAD, we want to make sure we signal |
| 522 | * POLLOUT, such that a subsequent write() can get a |
| 523 | * -ECONNREFUSED. Otherwise, if we haven't queued any skbs |
| 524 | * to other and its full, we will hang waiting for POLLOUT. |
| 525 | */ |
| 526 | if (unix_recvq_full_lockless(other) && !sock_flag(other, SOCK_DEAD)) |
| 527 | return 1; |
| 528 | |
| 529 | if (connected) |
| 530 | unix_dgram_peer_wake_disconnect(sk, other); |
| 531 | |
| 532 | return 0; |
| 533 | } |
| 534 | |
| 535 | static int unix_writable(const struct sock *sk) |
| 536 | { |
| 537 | return sk->sk_state != TCP_LISTEN && |
| 538 | (refcount_read(&sk->sk_wmem_alloc) << 2) <= sk->sk_sndbuf; |
| 539 | } |
| 540 | |
| 541 | static void unix_write_space(struct sock *sk) |
| 542 | { |
| 543 | struct socket_wq *wq; |
| 544 | |
| 545 | rcu_read_lock(); |
| 546 | if (unix_writable(sk)) { |
| 547 | wq = rcu_dereference(sk->sk_wq); |
| 548 | if (skwq_has_sleeper(wq)) |
| 549 | wake_up_interruptible_sync_poll(&wq->wait, |
| 550 | EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); |
| 551 | sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); |
| 552 | } |
| 553 | rcu_read_unlock(); |
| 554 | } |
| 555 | |
| 556 | /* When dgram socket disconnects (or changes its peer), we clear its receive |
| 557 | * queue of packets arrived from previous peer. First, it allows to do |
| 558 | * flow control based only on wmem_alloc; second, sk connected to peer |
| 559 | * may receive messages only from that peer. */ |
| 560 | static void unix_dgram_disconnected(struct sock *sk, struct sock *other) |
| 561 | { |
| 562 | if (!skb_queue_empty(&sk->sk_receive_queue)) { |
| 563 | skb_queue_purge(&sk->sk_receive_queue); |
| 564 | wake_up_interruptible_all(&unix_sk(sk)->peer_wait); |
| 565 | |
| 566 | /* If one link of bidirectional dgram pipe is disconnected, |
| 567 | * we signal error. Messages are lost. Do not make this, |
| 568 | * when peer was not connected to us. |
| 569 | */ |
| 570 | if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) { |
| 571 | WRITE_ONCE(other->sk_err, ECONNRESET); |
| 572 | sk_error_report(other); |
| 573 | } |
| 574 | } |
| 575 | other->sk_state = TCP_CLOSE; |
| 576 | } |
| 577 | |
| 578 | static void unix_sock_destructor(struct sock *sk) |
| 579 | { |
| 580 | struct unix_sock *u = unix_sk(sk); |
| 581 | |
| 582 | skb_queue_purge(&sk->sk_receive_queue); |
| 583 | |
| 584 | DEBUG_NET_WARN_ON_ONCE(refcount_read(&sk->sk_wmem_alloc)); |
| 585 | DEBUG_NET_WARN_ON_ONCE(!sk_unhashed(sk)); |
| 586 | DEBUG_NET_WARN_ON_ONCE(sk->sk_socket); |
| 587 | if (!sock_flag(sk, SOCK_DEAD)) { |
| 588 | pr_info("Attempt to release alive unix socket: %p\n", sk); |
| 589 | return; |
| 590 | } |
| 591 | |
| 592 | if (u->addr) |
| 593 | unix_release_addr(u->addr); |
| 594 | |
| 595 | atomic_long_dec(&unix_nr_socks); |
| 596 | sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); |
| 597 | #ifdef UNIX_REFCNT_DEBUG |
| 598 | pr_debug("UNIX %p is destroyed, %ld are still alive.\n", sk, |
| 599 | atomic_long_read(&unix_nr_socks)); |
| 600 | #endif |
| 601 | } |
| 602 | |
| 603 | static void unix_release_sock(struct sock *sk, int embrion) |
| 604 | { |
| 605 | struct unix_sock *u = unix_sk(sk); |
| 606 | struct sock *skpair; |
| 607 | struct sk_buff *skb; |
| 608 | struct path path; |
| 609 | int state; |
| 610 | |
| 611 | unix_remove_socket(sock_net(sk), sk); |
| 612 | unix_remove_bsd_socket(sk); |
| 613 | |
| 614 | /* Clear state */ |
| 615 | unix_state_lock(sk); |
| 616 | sock_orphan(sk); |
| 617 | WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); |
| 618 | path = u->path; |
| 619 | u->path.dentry = NULL; |
| 620 | u->path.mnt = NULL; |
| 621 | state = sk->sk_state; |
| 622 | sk->sk_state = TCP_CLOSE; |
| 623 | |
| 624 | skpair = unix_peer(sk); |
| 625 | unix_peer(sk) = NULL; |
| 626 | |
| 627 | unix_state_unlock(sk); |
| 628 | |
| 629 | #if IS_ENABLED(CONFIG_AF_UNIX_OOB) |
| 630 | if (u->oob_skb) { |
| 631 | kfree_skb(u->oob_skb); |
| 632 | u->oob_skb = NULL; |
| 633 | } |
| 634 | #endif |
| 635 | |
| 636 | wake_up_interruptible_all(&u->peer_wait); |
| 637 | |
| 638 | if (skpair != NULL) { |
| 639 | if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) { |
| 640 | unix_state_lock(skpair); |
| 641 | /* No more writes */ |
| 642 | WRITE_ONCE(skpair->sk_shutdown, SHUTDOWN_MASK); |
| 643 | if (!skb_queue_empty(&sk->sk_receive_queue) || embrion) |
| 644 | WRITE_ONCE(skpair->sk_err, ECONNRESET); |
| 645 | unix_state_unlock(skpair); |
| 646 | skpair->sk_state_change(skpair); |
| 647 | sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP); |
| 648 | } |
| 649 | |
| 650 | unix_dgram_peer_wake_disconnect(sk, skpair); |
| 651 | sock_put(skpair); /* It may now die */ |
| 652 | } |
| 653 | |
| 654 | /* Try to flush out this socket. Throw out buffers at least */ |
| 655 | |
| 656 | while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) { |
| 657 | if (state == TCP_LISTEN) |
| 658 | unix_release_sock(skb->sk, 1); |
| 659 | /* passed fds are erased in the kfree_skb hook */ |
| 660 | UNIXCB(skb).consumed = skb->len; |
| 661 | kfree_skb(skb); |
| 662 | } |
| 663 | |
| 664 | if (path.dentry) |
| 665 | path_put(&path); |
| 666 | |
| 667 | sock_put(sk); |
| 668 | |
| 669 | /* ---- Socket is dead now and most probably destroyed ---- */ |
| 670 | |
| 671 | /* |
| 672 | * Fixme: BSD difference: In BSD all sockets connected to us get |
| 673 | * ECONNRESET and we die on the spot. In Linux we behave |
| 674 | * like files and pipes do and wait for the last |
| 675 | * dereference. |
| 676 | * |
| 677 | * Can't we simply set sock->err? |
| 678 | * |
| 679 | * What the above comment does talk about? --ANK(980817) |
| 680 | */ |
| 681 | |
| 682 | if (READ_ONCE(unix_tot_inflight)) |
| 683 | unix_gc(); /* Garbage collect fds */ |
| 684 | } |
| 685 | |
| 686 | static void init_peercred(struct sock *sk) |
| 687 | { |
| 688 | const struct cred *old_cred; |
| 689 | struct pid *old_pid; |
| 690 | |
| 691 | spin_lock(&sk->sk_peer_lock); |
| 692 | old_pid = sk->sk_peer_pid; |
| 693 | old_cred = sk->sk_peer_cred; |
| 694 | sk->sk_peer_pid = get_pid(task_tgid(current)); |
| 695 | sk->sk_peer_cred = get_current_cred(); |
| 696 | spin_unlock(&sk->sk_peer_lock); |
| 697 | |
| 698 | put_pid(old_pid); |
| 699 | put_cred(old_cred); |
| 700 | } |
| 701 | |
| 702 | static void copy_peercred(struct sock *sk, struct sock *peersk) |
| 703 | { |
| 704 | const struct cred *old_cred; |
| 705 | struct pid *old_pid; |
| 706 | |
| 707 | if (sk < peersk) { |
| 708 | spin_lock(&sk->sk_peer_lock); |
| 709 | spin_lock_nested(&peersk->sk_peer_lock, SINGLE_DEPTH_NESTING); |
| 710 | } else { |
| 711 | spin_lock(&peersk->sk_peer_lock); |
| 712 | spin_lock_nested(&sk->sk_peer_lock, SINGLE_DEPTH_NESTING); |
| 713 | } |
| 714 | old_pid = sk->sk_peer_pid; |
| 715 | old_cred = sk->sk_peer_cred; |
| 716 | sk->sk_peer_pid = get_pid(peersk->sk_peer_pid); |
| 717 | sk->sk_peer_cred = get_cred(peersk->sk_peer_cred); |
| 718 | |
| 719 | spin_unlock(&sk->sk_peer_lock); |
| 720 | spin_unlock(&peersk->sk_peer_lock); |
| 721 | |
| 722 | put_pid(old_pid); |
| 723 | put_cred(old_cred); |
| 724 | } |
| 725 | |
| 726 | static int unix_listen(struct socket *sock, int backlog) |
| 727 | { |
| 728 | int err; |
| 729 | struct sock *sk = sock->sk; |
| 730 | struct unix_sock *u = unix_sk(sk); |
| 731 | |
| 732 | err = -EOPNOTSUPP; |
| 733 | if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) |
| 734 | goto out; /* Only stream/seqpacket sockets accept */ |
| 735 | err = -EINVAL; |
| 736 | if (!u->addr) |
| 737 | goto out; /* No listens on an unbound socket */ |
| 738 | unix_state_lock(sk); |
| 739 | if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN) |
| 740 | goto out_unlock; |
| 741 | if (backlog > sk->sk_max_ack_backlog) |
| 742 | wake_up_interruptible_all(&u->peer_wait); |
| 743 | sk->sk_max_ack_backlog = backlog; |
| 744 | sk->sk_state = TCP_LISTEN; |
| 745 | /* set credentials so connect can copy them */ |
| 746 | init_peercred(sk); |
| 747 | err = 0; |
| 748 | |
| 749 | out_unlock: |
| 750 | unix_state_unlock(sk); |
| 751 | out: |
| 752 | return err; |
| 753 | } |
| 754 | |
| 755 | static int unix_release(struct socket *); |
| 756 | static int unix_bind(struct socket *, struct sockaddr *, int); |
| 757 | static int unix_stream_connect(struct socket *, struct sockaddr *, |
| 758 | int addr_len, int flags); |
| 759 | static int unix_socketpair(struct socket *, struct socket *); |
| 760 | static int unix_accept(struct socket *, struct socket *, int, bool); |
| 761 | static int unix_getname(struct socket *, struct sockaddr *, int); |
| 762 | static __poll_t unix_poll(struct file *, struct socket *, poll_table *); |
| 763 | static __poll_t unix_dgram_poll(struct file *, struct socket *, |
| 764 | poll_table *); |
| 765 | static int unix_ioctl(struct socket *, unsigned int, unsigned long); |
| 766 | #ifdef CONFIG_COMPAT |
| 767 | static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg); |
| 768 | #endif |
| 769 | static int unix_shutdown(struct socket *, int); |
| 770 | static int unix_stream_sendmsg(struct socket *, struct msghdr *, size_t); |
| 771 | static int unix_stream_recvmsg(struct socket *, struct msghdr *, size_t, int); |
| 772 | static ssize_t unix_stream_splice_read(struct socket *, loff_t *ppos, |
| 773 | struct pipe_inode_info *, size_t size, |
| 774 | unsigned int flags); |
| 775 | static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t); |
| 776 | static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int); |
| 777 | static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor); |
| 778 | static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor); |
| 779 | static int unix_dgram_connect(struct socket *, struct sockaddr *, |
| 780 | int, int); |
| 781 | static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t); |
| 782 | static int unix_seqpacket_recvmsg(struct socket *, struct msghdr *, size_t, |
| 783 | int); |
| 784 | |
| 785 | #ifdef CONFIG_PROC_FS |
| 786 | static int unix_count_nr_fds(struct sock *sk) |
| 787 | { |
| 788 | struct sk_buff *skb; |
| 789 | struct unix_sock *u; |
| 790 | int nr_fds = 0; |
| 791 | |
| 792 | spin_lock(&sk->sk_receive_queue.lock); |
| 793 | skb = skb_peek(&sk->sk_receive_queue); |
| 794 | while (skb) { |
| 795 | u = unix_sk(skb->sk); |
| 796 | nr_fds += atomic_read(&u->scm_stat.nr_fds); |
| 797 | skb = skb_peek_next(skb, &sk->sk_receive_queue); |
| 798 | } |
| 799 | spin_unlock(&sk->sk_receive_queue.lock); |
| 800 | |
| 801 | return nr_fds; |
| 802 | } |
| 803 | |
| 804 | static void unix_show_fdinfo(struct seq_file *m, struct socket *sock) |
| 805 | { |
| 806 | struct sock *sk = sock->sk; |
| 807 | unsigned char s_state; |
| 808 | struct unix_sock *u; |
| 809 | int nr_fds = 0; |
| 810 | |
| 811 | if (sk) { |
| 812 | s_state = READ_ONCE(sk->sk_state); |
| 813 | u = unix_sk(sk); |
| 814 | |
| 815 | /* SOCK_STREAM and SOCK_SEQPACKET sockets never change their |
| 816 | * sk_state after switching to TCP_ESTABLISHED or TCP_LISTEN. |
| 817 | * SOCK_DGRAM is ordinary. So, no lock is needed. |
| 818 | */ |
| 819 | if (sock->type == SOCK_DGRAM || s_state == TCP_ESTABLISHED) |
| 820 | nr_fds = atomic_read(&u->scm_stat.nr_fds); |
| 821 | else if (s_state == TCP_LISTEN) |
| 822 | nr_fds = unix_count_nr_fds(sk); |
| 823 | |
| 824 | seq_printf(m, "scm_fds: %u\n", nr_fds); |
| 825 | } |
| 826 | } |
| 827 | #else |
| 828 | #define unix_show_fdinfo NULL |
| 829 | #endif |
| 830 | |
| 831 | static const struct proto_ops unix_stream_ops = { |
| 832 | .family = PF_UNIX, |
| 833 | .owner = THIS_MODULE, |
| 834 | .release = unix_release, |
| 835 | .bind = unix_bind, |
| 836 | .connect = unix_stream_connect, |
| 837 | .socketpair = unix_socketpair, |
| 838 | .accept = unix_accept, |
| 839 | .getname = unix_getname, |
| 840 | .poll = unix_poll, |
| 841 | .ioctl = unix_ioctl, |
| 842 | #ifdef CONFIG_COMPAT |
| 843 | .compat_ioctl = unix_compat_ioctl, |
| 844 | #endif |
| 845 | .listen = unix_listen, |
| 846 | .shutdown = unix_shutdown, |
| 847 | .sendmsg = unix_stream_sendmsg, |
| 848 | .recvmsg = unix_stream_recvmsg, |
| 849 | .read_skb = unix_stream_read_skb, |
| 850 | .mmap = sock_no_mmap, |
| 851 | .splice_read = unix_stream_splice_read, |
| 852 | .set_peek_off = sk_set_peek_off, |
| 853 | .show_fdinfo = unix_show_fdinfo, |
| 854 | }; |
| 855 | |
| 856 | static const struct proto_ops unix_dgram_ops = { |
| 857 | .family = PF_UNIX, |
| 858 | .owner = THIS_MODULE, |
| 859 | .release = unix_release, |
| 860 | .bind = unix_bind, |
| 861 | .connect = unix_dgram_connect, |
| 862 | .socketpair = unix_socketpair, |
| 863 | .accept = sock_no_accept, |
| 864 | .getname = unix_getname, |
| 865 | .poll = unix_dgram_poll, |
| 866 | .ioctl = unix_ioctl, |
| 867 | #ifdef CONFIG_COMPAT |
| 868 | .compat_ioctl = unix_compat_ioctl, |
| 869 | #endif |
| 870 | .listen = sock_no_listen, |
| 871 | .shutdown = unix_shutdown, |
| 872 | .sendmsg = unix_dgram_sendmsg, |
| 873 | .read_skb = unix_read_skb, |
| 874 | .recvmsg = unix_dgram_recvmsg, |
| 875 | .mmap = sock_no_mmap, |
| 876 | .set_peek_off = sk_set_peek_off, |
| 877 | .show_fdinfo = unix_show_fdinfo, |
| 878 | }; |
| 879 | |
| 880 | static const struct proto_ops unix_seqpacket_ops = { |
| 881 | .family = PF_UNIX, |
| 882 | .owner = THIS_MODULE, |
| 883 | .release = unix_release, |
| 884 | .bind = unix_bind, |
| 885 | .connect = unix_stream_connect, |
| 886 | .socketpair = unix_socketpair, |
| 887 | .accept = unix_accept, |
| 888 | .getname = unix_getname, |
| 889 | .poll = unix_dgram_poll, |
| 890 | .ioctl = unix_ioctl, |
| 891 | #ifdef CONFIG_COMPAT |
| 892 | .compat_ioctl = unix_compat_ioctl, |
| 893 | #endif |
| 894 | .listen = unix_listen, |
| 895 | .shutdown = unix_shutdown, |
| 896 | .sendmsg = unix_seqpacket_sendmsg, |
| 897 | .recvmsg = unix_seqpacket_recvmsg, |
| 898 | .mmap = sock_no_mmap, |
| 899 | .set_peek_off = sk_set_peek_off, |
| 900 | .show_fdinfo = unix_show_fdinfo, |
| 901 | }; |
| 902 | |
| 903 | static void unix_close(struct sock *sk, long timeout) |
| 904 | { |
| 905 | /* Nothing to do here, unix socket does not need a ->close(). |
| 906 | * This is merely for sockmap. |
| 907 | */ |
| 908 | } |
| 909 | |
| 910 | static void unix_unhash(struct sock *sk) |
| 911 | { |
| 912 | /* Nothing to do here, unix socket does not need a ->unhash(). |
| 913 | * This is merely for sockmap. |
| 914 | */ |
| 915 | } |
| 916 | |
| 917 | static bool unix_bpf_bypass_getsockopt(int level, int optname) |
| 918 | { |
| 919 | if (level == SOL_SOCKET) { |
| 920 | switch (optname) { |
| 921 | case SO_PEERPIDFD: |
| 922 | return true; |
| 923 | default: |
| 924 | return false; |
| 925 | } |
| 926 | } |
| 927 | |
| 928 | return false; |
| 929 | } |
| 930 | |
| 931 | struct proto unix_dgram_proto = { |
| 932 | .name = "UNIX", |
| 933 | .owner = THIS_MODULE, |
| 934 | .obj_size = sizeof(struct unix_sock), |
| 935 | .close = unix_close, |
| 936 | .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt, |
| 937 | #ifdef CONFIG_BPF_SYSCALL |
| 938 | .psock_update_sk_prot = unix_dgram_bpf_update_proto, |
| 939 | #endif |
| 940 | }; |
| 941 | |
| 942 | struct proto unix_stream_proto = { |
| 943 | .name = "UNIX-STREAM", |
| 944 | .owner = THIS_MODULE, |
| 945 | .obj_size = sizeof(struct unix_sock), |
| 946 | .close = unix_close, |
| 947 | .unhash = unix_unhash, |
| 948 | .bpf_bypass_getsockopt = unix_bpf_bypass_getsockopt, |
| 949 | #ifdef CONFIG_BPF_SYSCALL |
| 950 | .psock_update_sk_prot = unix_stream_bpf_update_proto, |
| 951 | #endif |
| 952 | }; |
| 953 | |
| 954 | static struct sock *unix_create1(struct net *net, struct socket *sock, int kern, int type) |
| 955 | { |
| 956 | struct unix_sock *u; |
| 957 | struct sock *sk; |
| 958 | int err; |
| 959 | |
| 960 | atomic_long_inc(&unix_nr_socks); |
| 961 | if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files()) { |
| 962 | err = -ENFILE; |
| 963 | goto err; |
| 964 | } |
| 965 | |
| 966 | if (type == SOCK_STREAM) |
| 967 | sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_stream_proto, kern); |
| 968 | else /*dgram and seqpacket */ |
| 969 | sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_dgram_proto, kern); |
| 970 | |
| 971 | if (!sk) { |
| 972 | err = -ENOMEM; |
| 973 | goto err; |
| 974 | } |
| 975 | |
| 976 | sock_init_data(sock, sk); |
| 977 | |
| 978 | sk->sk_hash = unix_unbound_hash(sk); |
| 979 | sk->sk_allocation = GFP_KERNEL_ACCOUNT; |
| 980 | sk->sk_write_space = unix_write_space; |
| 981 | sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen; |
| 982 | sk->sk_destruct = unix_sock_destructor; |
| 983 | u = unix_sk(sk); |
| 984 | u->path.dentry = NULL; |
| 985 | u->path.mnt = NULL; |
| 986 | spin_lock_init(&u->lock); |
| 987 | atomic_long_set(&u->inflight, 0); |
| 988 | INIT_LIST_HEAD(&u->link); |
| 989 | mutex_init(&u->iolock); /* single task reading lock */ |
| 990 | mutex_init(&u->bindlock); /* single task binding lock */ |
| 991 | init_waitqueue_head(&u->peer_wait); |
| 992 | init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay); |
| 993 | memset(&u->scm_stat, 0, sizeof(struct scm_stat)); |
| 994 | unix_insert_unbound_socket(net, sk); |
| 995 | |
| 996 | sock_prot_inuse_add(net, sk->sk_prot, 1); |
| 997 | |
| 998 | return sk; |
| 999 | |
| 1000 | err: |
| 1001 | atomic_long_dec(&unix_nr_socks); |
| 1002 | return ERR_PTR(err); |
| 1003 | } |
| 1004 | |
| 1005 | static int unix_create(struct net *net, struct socket *sock, int protocol, |
| 1006 | int kern) |
| 1007 | { |
| 1008 | struct sock *sk; |
| 1009 | |
| 1010 | if (protocol && protocol != PF_UNIX) |
| 1011 | return -EPROTONOSUPPORT; |
| 1012 | |
| 1013 | sock->state = SS_UNCONNECTED; |
| 1014 | |
| 1015 | switch (sock->type) { |
| 1016 | case SOCK_STREAM: |
| 1017 | sock->ops = &unix_stream_ops; |
| 1018 | break; |
| 1019 | /* |
| 1020 | * Believe it or not BSD has AF_UNIX, SOCK_RAW though |
| 1021 | * nothing uses it. |
| 1022 | */ |
| 1023 | case SOCK_RAW: |
| 1024 | sock->type = SOCK_DGRAM; |
| 1025 | fallthrough; |
| 1026 | case SOCK_DGRAM: |
| 1027 | sock->ops = &unix_dgram_ops; |
| 1028 | break; |
| 1029 | case SOCK_SEQPACKET: |
| 1030 | sock->ops = &unix_seqpacket_ops; |
| 1031 | break; |
| 1032 | default: |
| 1033 | return -ESOCKTNOSUPPORT; |
| 1034 | } |
| 1035 | |
| 1036 | sk = unix_create1(net, sock, kern, sock->type); |
| 1037 | if (IS_ERR(sk)) |
| 1038 | return PTR_ERR(sk); |
| 1039 | |
| 1040 | return 0; |
| 1041 | } |
| 1042 | |
| 1043 | static int unix_release(struct socket *sock) |
| 1044 | { |
| 1045 | struct sock *sk = sock->sk; |
| 1046 | |
| 1047 | if (!sk) |
| 1048 | return 0; |
| 1049 | |
| 1050 | sk->sk_prot->close(sk, 0); |
| 1051 | unix_release_sock(sk, 0); |
| 1052 | sock->sk = NULL; |
| 1053 | |
| 1054 | return 0; |
| 1055 | } |
| 1056 | |
| 1057 | static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len, |
| 1058 | int type) |
| 1059 | { |
| 1060 | struct inode *inode; |
| 1061 | struct path path; |
| 1062 | struct sock *sk; |
| 1063 | int err; |
| 1064 | |
| 1065 | unix_mkname_bsd(sunaddr, addr_len); |
| 1066 | err = kern_path(sunaddr->sun_path, LOOKUP_FOLLOW, &path); |
| 1067 | if (err) |
| 1068 | goto fail; |
| 1069 | |
| 1070 | err = path_permission(&path, MAY_WRITE); |
| 1071 | if (err) |
| 1072 | goto path_put; |
| 1073 | |
| 1074 | err = -ECONNREFUSED; |
| 1075 | inode = d_backing_inode(path.dentry); |
| 1076 | if (!S_ISSOCK(inode->i_mode)) |
| 1077 | goto path_put; |
| 1078 | |
| 1079 | sk = unix_find_socket_byinode(inode); |
| 1080 | if (!sk) |
| 1081 | goto path_put; |
| 1082 | |
| 1083 | err = -EPROTOTYPE; |
| 1084 | if (sk->sk_type == type) |
| 1085 | touch_atime(&path); |
| 1086 | else |
| 1087 | goto sock_put; |
| 1088 | |
| 1089 | path_put(&path); |
| 1090 | |
| 1091 | return sk; |
| 1092 | |
| 1093 | sock_put: |
| 1094 | sock_put(sk); |
| 1095 | path_put: |
| 1096 | path_put(&path); |
| 1097 | fail: |
| 1098 | return ERR_PTR(err); |
| 1099 | } |
| 1100 | |
| 1101 | static struct sock *unix_find_abstract(struct net *net, |
| 1102 | struct sockaddr_un *sunaddr, |
| 1103 | int addr_len, int type) |
| 1104 | { |
| 1105 | unsigned int hash = unix_abstract_hash(sunaddr, addr_len, type); |
| 1106 | struct dentry *dentry; |
| 1107 | struct sock *sk; |
| 1108 | |
| 1109 | sk = unix_find_socket_byname(net, sunaddr, addr_len, hash); |
| 1110 | if (!sk) |
| 1111 | return ERR_PTR(-ECONNREFUSED); |
| 1112 | |
| 1113 | dentry = unix_sk(sk)->path.dentry; |
| 1114 | if (dentry) |
| 1115 | touch_atime(&unix_sk(sk)->path); |
| 1116 | |
| 1117 | return sk; |
| 1118 | } |
| 1119 | |
| 1120 | static struct sock *unix_find_other(struct net *net, |
| 1121 | struct sockaddr_un *sunaddr, |
| 1122 | int addr_len, int type) |
| 1123 | { |
| 1124 | struct sock *sk; |
| 1125 | |
| 1126 | if (sunaddr->sun_path[0]) |
| 1127 | sk = unix_find_bsd(sunaddr, addr_len, type); |
| 1128 | else |
| 1129 | sk = unix_find_abstract(net, sunaddr, addr_len, type); |
| 1130 | |
| 1131 | return sk; |
| 1132 | } |
| 1133 | |
| 1134 | static int unix_autobind(struct sock *sk) |
| 1135 | { |
| 1136 | unsigned int new_hash, old_hash = sk->sk_hash; |
| 1137 | struct unix_sock *u = unix_sk(sk); |
| 1138 | struct net *net = sock_net(sk); |
| 1139 | struct unix_address *addr; |
| 1140 | u32 lastnum, ordernum; |
| 1141 | int err; |
| 1142 | |
| 1143 | err = mutex_lock_interruptible(&u->bindlock); |
| 1144 | if (err) |
| 1145 | return err; |
| 1146 | |
| 1147 | if (u->addr) |
| 1148 | goto out; |
| 1149 | |
| 1150 | err = -ENOMEM; |
| 1151 | addr = kzalloc(sizeof(*addr) + |
| 1152 | offsetof(struct sockaddr_un, sun_path) + 16, GFP_KERNEL); |
| 1153 | if (!addr) |
| 1154 | goto out; |
| 1155 | |
| 1156 | addr->len = offsetof(struct sockaddr_un, sun_path) + 6; |
| 1157 | addr->name->sun_family = AF_UNIX; |
| 1158 | refcount_set(&addr->refcnt, 1); |
| 1159 | |
| 1160 | ordernum = get_random_u32(); |
| 1161 | lastnum = ordernum & 0xFFFFF; |
| 1162 | retry: |
| 1163 | ordernum = (ordernum + 1) & 0xFFFFF; |
| 1164 | sprintf(addr->name->sun_path + 1, "%05x", ordernum); |
| 1165 | |
| 1166 | new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type); |
| 1167 | unix_table_double_lock(net, old_hash, new_hash); |
| 1168 | |
| 1169 | if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) { |
| 1170 | unix_table_double_unlock(net, old_hash, new_hash); |
| 1171 | |
| 1172 | /* __unix_find_socket_byname() may take long time if many names |
| 1173 | * are already in use. |
| 1174 | */ |
| 1175 | cond_resched(); |
| 1176 | |
| 1177 | if (ordernum == lastnum) { |
| 1178 | /* Give up if all names seems to be in use. */ |
| 1179 | err = -ENOSPC; |
| 1180 | unix_release_addr(addr); |
| 1181 | goto out; |
| 1182 | } |
| 1183 | |
| 1184 | goto retry; |
| 1185 | } |
| 1186 | |
| 1187 | __unix_set_addr_hash(net, sk, addr, new_hash); |
| 1188 | unix_table_double_unlock(net, old_hash, new_hash); |
| 1189 | err = 0; |
| 1190 | |
| 1191 | out: mutex_unlock(&u->bindlock); |
| 1192 | return err; |
| 1193 | } |
| 1194 | |
| 1195 | static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr, |
| 1196 | int addr_len) |
| 1197 | { |
| 1198 | umode_t mode = S_IFSOCK | |
| 1199 | (SOCK_INODE(sk->sk_socket)->i_mode & ~current_umask()); |
| 1200 | unsigned int new_hash, old_hash = sk->sk_hash; |
| 1201 | struct unix_sock *u = unix_sk(sk); |
| 1202 | struct net *net = sock_net(sk); |
| 1203 | struct mnt_idmap *idmap; |
| 1204 | struct unix_address *addr; |
| 1205 | struct dentry *dentry; |
| 1206 | struct path parent; |
| 1207 | int err; |
| 1208 | |
| 1209 | addr_len = unix_mkname_bsd(sunaddr, addr_len); |
| 1210 | addr = unix_create_addr(sunaddr, addr_len); |
| 1211 | if (!addr) |
| 1212 | return -ENOMEM; |
| 1213 | |
| 1214 | /* |
| 1215 | * Get the parent directory, calculate the hash for last |
| 1216 | * component. |
| 1217 | */ |
| 1218 | dentry = kern_path_create(AT_FDCWD, addr->name->sun_path, &parent, 0); |
| 1219 | if (IS_ERR(dentry)) { |
| 1220 | err = PTR_ERR(dentry); |
| 1221 | goto out; |
| 1222 | } |
| 1223 | |
| 1224 | /* |
| 1225 | * All right, let's create it. |
| 1226 | */ |
| 1227 | idmap = mnt_idmap(parent.mnt); |
| 1228 | err = security_path_mknod(&parent, dentry, mode, 0); |
| 1229 | if (!err) |
| 1230 | err = vfs_mknod(idmap, d_inode(parent.dentry), dentry, mode, 0); |
| 1231 | if (err) |
| 1232 | goto out_path; |
| 1233 | err = mutex_lock_interruptible(&u->bindlock); |
| 1234 | if (err) |
| 1235 | goto out_unlink; |
| 1236 | if (u->addr) |
| 1237 | goto out_unlock; |
| 1238 | |
| 1239 | new_hash = unix_bsd_hash(d_backing_inode(dentry)); |
| 1240 | unix_table_double_lock(net, old_hash, new_hash); |
| 1241 | u->path.mnt = mntget(parent.mnt); |
| 1242 | u->path.dentry = dget(dentry); |
| 1243 | __unix_set_addr_hash(net, sk, addr, new_hash); |
| 1244 | unix_table_double_unlock(net, old_hash, new_hash); |
| 1245 | unix_insert_bsd_socket(sk); |
| 1246 | mutex_unlock(&u->bindlock); |
| 1247 | done_path_create(&parent, dentry); |
| 1248 | return 0; |
| 1249 | |
| 1250 | out_unlock: |
| 1251 | mutex_unlock(&u->bindlock); |
| 1252 | err = -EINVAL; |
| 1253 | out_unlink: |
| 1254 | /* failed after successful mknod? unlink what we'd created... */ |
| 1255 | vfs_unlink(idmap, d_inode(parent.dentry), dentry, NULL); |
| 1256 | out_path: |
| 1257 | done_path_create(&parent, dentry); |
| 1258 | out: |
| 1259 | unix_release_addr(addr); |
| 1260 | return err == -EEXIST ? -EADDRINUSE : err; |
| 1261 | } |
| 1262 | |
| 1263 | static int unix_bind_abstract(struct sock *sk, struct sockaddr_un *sunaddr, |
| 1264 | int addr_len) |
| 1265 | { |
| 1266 | unsigned int new_hash, old_hash = sk->sk_hash; |
| 1267 | struct unix_sock *u = unix_sk(sk); |
| 1268 | struct net *net = sock_net(sk); |
| 1269 | struct unix_address *addr; |
| 1270 | int err; |
| 1271 | |
| 1272 | addr = unix_create_addr(sunaddr, addr_len); |
| 1273 | if (!addr) |
| 1274 | return -ENOMEM; |
| 1275 | |
| 1276 | err = mutex_lock_interruptible(&u->bindlock); |
| 1277 | if (err) |
| 1278 | goto out; |
| 1279 | |
| 1280 | if (u->addr) { |
| 1281 | err = -EINVAL; |
| 1282 | goto out_mutex; |
| 1283 | } |
| 1284 | |
| 1285 | new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type); |
| 1286 | unix_table_double_lock(net, old_hash, new_hash); |
| 1287 | |
| 1288 | if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) |
| 1289 | goto out_spin; |
| 1290 | |
| 1291 | __unix_set_addr_hash(net, sk, addr, new_hash); |
| 1292 | unix_table_double_unlock(net, old_hash, new_hash); |
| 1293 | mutex_unlock(&u->bindlock); |
| 1294 | return 0; |
| 1295 | |
| 1296 | out_spin: |
| 1297 | unix_table_double_unlock(net, old_hash, new_hash); |
| 1298 | err = -EADDRINUSE; |
| 1299 | out_mutex: |
| 1300 | mutex_unlock(&u->bindlock); |
| 1301 | out: |
| 1302 | unix_release_addr(addr); |
| 1303 | return err; |
| 1304 | } |
| 1305 | |
| 1306 | static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) |
| 1307 | { |
| 1308 | struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; |
| 1309 | struct sock *sk = sock->sk; |
| 1310 | int err; |
| 1311 | |
| 1312 | if (addr_len == offsetof(struct sockaddr_un, sun_path) && |
| 1313 | sunaddr->sun_family == AF_UNIX) |
| 1314 | return unix_autobind(sk); |
| 1315 | |
| 1316 | err = unix_validate_addr(sunaddr, addr_len); |
| 1317 | if (err) |
| 1318 | return err; |
| 1319 | |
| 1320 | if (sunaddr->sun_path[0]) |
| 1321 | err = unix_bind_bsd(sk, sunaddr, addr_len); |
| 1322 | else |
| 1323 | err = unix_bind_abstract(sk, sunaddr, addr_len); |
| 1324 | |
| 1325 | return err; |
| 1326 | } |
| 1327 | |
| 1328 | static void unix_state_double_lock(struct sock *sk1, struct sock *sk2) |
| 1329 | { |
| 1330 | if (unlikely(sk1 == sk2) || !sk2) { |
| 1331 | unix_state_lock(sk1); |
| 1332 | return; |
| 1333 | } |
| 1334 | if (sk1 > sk2) |
| 1335 | swap(sk1, sk2); |
| 1336 | |
| 1337 | unix_state_lock(sk1); |
| 1338 | unix_state_lock_nested(sk2, U_LOCK_SECOND); |
| 1339 | } |
| 1340 | |
| 1341 | static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2) |
| 1342 | { |
| 1343 | if (unlikely(sk1 == sk2) || !sk2) { |
| 1344 | unix_state_unlock(sk1); |
| 1345 | return; |
| 1346 | } |
| 1347 | unix_state_unlock(sk1); |
| 1348 | unix_state_unlock(sk2); |
| 1349 | } |
| 1350 | |
| 1351 | static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, |
| 1352 | int alen, int flags) |
| 1353 | { |
| 1354 | struct sockaddr_un *sunaddr = (struct sockaddr_un *)addr; |
| 1355 | struct sock *sk = sock->sk; |
| 1356 | struct sock *other; |
| 1357 | int err; |
| 1358 | |
| 1359 | err = -EINVAL; |
| 1360 | if (alen < offsetofend(struct sockaddr, sa_family)) |
| 1361 | goto out; |
| 1362 | |
| 1363 | if (addr->sa_family != AF_UNSPEC) { |
| 1364 | err = unix_validate_addr(sunaddr, alen); |
| 1365 | if (err) |
| 1366 | goto out; |
| 1367 | |
| 1368 | err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, addr, &alen); |
| 1369 | if (err) |
| 1370 | goto out; |
| 1371 | |
| 1372 | if ((test_bit(SOCK_PASSCRED, &sock->flags) || |
| 1373 | test_bit(SOCK_PASSPIDFD, &sock->flags)) && |
| 1374 | !unix_sk(sk)->addr) { |
| 1375 | err = unix_autobind(sk); |
| 1376 | if (err) |
| 1377 | goto out; |
| 1378 | } |
| 1379 | |
| 1380 | restart: |
| 1381 | other = unix_find_other(sock_net(sk), sunaddr, alen, sock->type); |
| 1382 | if (IS_ERR(other)) { |
| 1383 | err = PTR_ERR(other); |
| 1384 | goto out; |
| 1385 | } |
| 1386 | |
| 1387 | unix_state_double_lock(sk, other); |
| 1388 | |
| 1389 | /* Apparently VFS overslept socket death. Retry. */ |
| 1390 | if (sock_flag(other, SOCK_DEAD)) { |
| 1391 | unix_state_double_unlock(sk, other); |
| 1392 | sock_put(other); |
| 1393 | goto restart; |
| 1394 | } |
| 1395 | |
| 1396 | err = -EPERM; |
| 1397 | if (!unix_may_send(sk, other)) |
| 1398 | goto out_unlock; |
| 1399 | |
| 1400 | err = security_unix_may_send(sk->sk_socket, other->sk_socket); |
| 1401 | if (err) |
| 1402 | goto out_unlock; |
| 1403 | |
| 1404 | sk->sk_state = other->sk_state = TCP_ESTABLISHED; |
| 1405 | } else { |
| 1406 | /* |
| 1407 | * 1003.1g breaking connected state with AF_UNSPEC |
| 1408 | */ |
| 1409 | other = NULL; |
| 1410 | unix_state_double_lock(sk, other); |
| 1411 | } |
| 1412 | |
| 1413 | /* |
| 1414 | * If it was connected, reconnect. |
| 1415 | */ |
| 1416 | if (unix_peer(sk)) { |
| 1417 | struct sock *old_peer = unix_peer(sk); |
| 1418 | |
| 1419 | unix_peer(sk) = other; |
| 1420 | if (!other) |
| 1421 | sk->sk_state = TCP_CLOSE; |
| 1422 | unix_dgram_peer_wake_disconnect_wakeup(sk, old_peer); |
| 1423 | |
| 1424 | unix_state_double_unlock(sk, other); |
| 1425 | |
| 1426 | if (other != old_peer) |
| 1427 | unix_dgram_disconnected(sk, old_peer); |
| 1428 | sock_put(old_peer); |
| 1429 | } else { |
| 1430 | unix_peer(sk) = other; |
| 1431 | unix_state_double_unlock(sk, other); |
| 1432 | } |
| 1433 | |
| 1434 | return 0; |
| 1435 | |
| 1436 | out_unlock: |
| 1437 | unix_state_double_unlock(sk, other); |
| 1438 | sock_put(other); |
| 1439 | out: |
| 1440 | return err; |
| 1441 | } |
| 1442 | |
| 1443 | static long unix_wait_for_peer(struct sock *other, long timeo) |
| 1444 | __releases(&unix_sk(other)->lock) |
| 1445 | { |
| 1446 | struct unix_sock *u = unix_sk(other); |
| 1447 | int sched; |
| 1448 | DEFINE_WAIT(wait); |
| 1449 | |
| 1450 | prepare_to_wait_exclusive(&u->peer_wait, &wait, TASK_INTERRUPTIBLE); |
| 1451 | |
| 1452 | sched = !sock_flag(other, SOCK_DEAD) && |
| 1453 | !(other->sk_shutdown & RCV_SHUTDOWN) && |
| 1454 | unix_recvq_full_lockless(other); |
| 1455 | |
| 1456 | unix_state_unlock(other); |
| 1457 | |
| 1458 | if (sched) |
| 1459 | timeo = schedule_timeout(timeo); |
| 1460 | |
| 1461 | finish_wait(&u->peer_wait, &wait); |
| 1462 | return timeo; |
| 1463 | } |
| 1464 | |
| 1465 | static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, |
| 1466 | int addr_len, int flags) |
| 1467 | { |
| 1468 | struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; |
| 1469 | struct sock *sk = sock->sk, *newsk = NULL, *other = NULL; |
| 1470 | struct unix_sock *u = unix_sk(sk), *newu, *otheru; |
| 1471 | struct net *net = sock_net(sk); |
| 1472 | struct sk_buff *skb = NULL; |
| 1473 | long timeo; |
| 1474 | int err; |
| 1475 | int st; |
| 1476 | |
| 1477 | err = unix_validate_addr(sunaddr, addr_len); |
| 1478 | if (err) |
| 1479 | goto out; |
| 1480 | |
| 1481 | err = BPF_CGROUP_RUN_PROG_UNIX_CONNECT_LOCK(sk, uaddr, &addr_len); |
| 1482 | if (err) |
| 1483 | goto out; |
| 1484 | |
| 1485 | if ((test_bit(SOCK_PASSCRED, &sock->flags) || |
| 1486 | test_bit(SOCK_PASSPIDFD, &sock->flags)) && !u->addr) { |
| 1487 | err = unix_autobind(sk); |
| 1488 | if (err) |
| 1489 | goto out; |
| 1490 | } |
| 1491 | |
| 1492 | timeo = sock_sndtimeo(sk, flags & O_NONBLOCK); |
| 1493 | |
| 1494 | /* First of all allocate resources. |
| 1495 | If we will make it after state is locked, |
| 1496 | we will have to recheck all again in any case. |
| 1497 | */ |
| 1498 | |
| 1499 | /* create new sock for complete connection */ |
| 1500 | newsk = unix_create1(net, NULL, 0, sock->type); |
| 1501 | if (IS_ERR(newsk)) { |
| 1502 | err = PTR_ERR(newsk); |
| 1503 | newsk = NULL; |
| 1504 | goto out; |
| 1505 | } |
| 1506 | |
| 1507 | err = -ENOMEM; |
| 1508 | |
| 1509 | /* Allocate skb for sending to listening sock */ |
| 1510 | skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL); |
| 1511 | if (skb == NULL) |
| 1512 | goto out; |
| 1513 | |
| 1514 | restart: |
| 1515 | /* Find listening sock. */ |
| 1516 | other = unix_find_other(net, sunaddr, addr_len, sk->sk_type); |
| 1517 | if (IS_ERR(other)) { |
| 1518 | err = PTR_ERR(other); |
| 1519 | other = NULL; |
| 1520 | goto out; |
| 1521 | } |
| 1522 | |
| 1523 | /* Latch state of peer */ |
| 1524 | unix_state_lock(other); |
| 1525 | |
| 1526 | /* Apparently VFS overslept socket death. Retry. */ |
| 1527 | if (sock_flag(other, SOCK_DEAD)) { |
| 1528 | unix_state_unlock(other); |
| 1529 | sock_put(other); |
| 1530 | goto restart; |
| 1531 | } |
| 1532 | |
| 1533 | err = -ECONNREFUSED; |
| 1534 | if (other->sk_state != TCP_LISTEN) |
| 1535 | goto out_unlock; |
| 1536 | if (other->sk_shutdown & RCV_SHUTDOWN) |
| 1537 | goto out_unlock; |
| 1538 | |
| 1539 | if (unix_recvq_full(other)) { |
| 1540 | err = -EAGAIN; |
| 1541 | if (!timeo) |
| 1542 | goto out_unlock; |
| 1543 | |
| 1544 | timeo = unix_wait_for_peer(other, timeo); |
| 1545 | |
| 1546 | err = sock_intr_errno(timeo); |
| 1547 | if (signal_pending(current)) |
| 1548 | goto out; |
| 1549 | sock_put(other); |
| 1550 | goto restart; |
| 1551 | } |
| 1552 | |
| 1553 | /* Latch our state. |
| 1554 | |
| 1555 | It is tricky place. We need to grab our state lock and cannot |
| 1556 | drop lock on peer. It is dangerous because deadlock is |
| 1557 | possible. Connect to self case and simultaneous |
| 1558 | attempt to connect are eliminated by checking socket |
| 1559 | state. other is TCP_LISTEN, if sk is TCP_LISTEN we |
| 1560 | check this before attempt to grab lock. |
| 1561 | |
| 1562 | Well, and we have to recheck the state after socket locked. |
| 1563 | */ |
| 1564 | st = sk->sk_state; |
| 1565 | |
| 1566 | switch (st) { |
| 1567 | case TCP_CLOSE: |
| 1568 | /* This is ok... continue with connect */ |
| 1569 | break; |
| 1570 | case TCP_ESTABLISHED: |
| 1571 | /* Socket is already connected */ |
| 1572 | err = -EISCONN; |
| 1573 | goto out_unlock; |
| 1574 | default: |
| 1575 | err = -EINVAL; |
| 1576 | goto out_unlock; |
| 1577 | } |
| 1578 | |
| 1579 | unix_state_lock_nested(sk, U_LOCK_SECOND); |
| 1580 | |
| 1581 | if (sk->sk_state != st) { |
| 1582 | unix_state_unlock(sk); |
| 1583 | unix_state_unlock(other); |
| 1584 | sock_put(other); |
| 1585 | goto restart; |
| 1586 | } |
| 1587 | |
| 1588 | err = security_unix_stream_connect(sk, other, newsk); |
| 1589 | if (err) { |
| 1590 | unix_state_unlock(sk); |
| 1591 | goto out_unlock; |
| 1592 | } |
| 1593 | |
| 1594 | /* The way is open! Fastly set all the necessary fields... */ |
| 1595 | |
| 1596 | sock_hold(sk); |
| 1597 | unix_peer(newsk) = sk; |
| 1598 | newsk->sk_state = TCP_ESTABLISHED; |
| 1599 | newsk->sk_type = sk->sk_type; |
| 1600 | init_peercred(newsk); |
| 1601 | newu = unix_sk(newsk); |
| 1602 | RCU_INIT_POINTER(newsk->sk_wq, &newu->peer_wq); |
| 1603 | otheru = unix_sk(other); |
| 1604 | |
| 1605 | /* copy address information from listening to new sock |
| 1606 | * |
| 1607 | * The contents of *(otheru->addr) and otheru->path |
| 1608 | * are seen fully set up here, since we have found |
| 1609 | * otheru in hash under its lock. Insertion into the |
| 1610 | * hash chain we'd found it in had been done in an |
| 1611 | * earlier critical area protected by the chain's lock, |
| 1612 | * the same one where we'd set *(otheru->addr) contents, |
| 1613 | * as well as otheru->path and otheru->addr itself. |
| 1614 | * |
| 1615 | * Using smp_store_release() here to set newu->addr |
| 1616 | * is enough to make those stores, as well as stores |
| 1617 | * to newu->path visible to anyone who gets newu->addr |
| 1618 | * by smp_load_acquire(). IOW, the same warranties |
| 1619 | * as for unix_sock instances bound in unix_bind() or |
| 1620 | * in unix_autobind(). |
| 1621 | */ |
| 1622 | if (otheru->path.dentry) { |
| 1623 | path_get(&otheru->path); |
| 1624 | newu->path = otheru->path; |
| 1625 | } |
| 1626 | refcount_inc(&otheru->addr->refcnt); |
| 1627 | smp_store_release(&newu->addr, otheru->addr); |
| 1628 | |
| 1629 | /* Set credentials */ |
| 1630 | copy_peercred(sk, other); |
| 1631 | |
| 1632 | sock->state = SS_CONNECTED; |
| 1633 | sk->sk_state = TCP_ESTABLISHED; |
| 1634 | sock_hold(newsk); |
| 1635 | |
| 1636 | smp_mb__after_atomic(); /* sock_hold() does an atomic_inc() */ |
| 1637 | unix_peer(sk) = newsk; |
| 1638 | |
| 1639 | unix_state_unlock(sk); |
| 1640 | |
| 1641 | /* take ten and send info to listening sock */ |
| 1642 | spin_lock(&other->sk_receive_queue.lock); |
| 1643 | __skb_queue_tail(&other->sk_receive_queue, skb); |
| 1644 | spin_unlock(&other->sk_receive_queue.lock); |
| 1645 | unix_state_unlock(other); |
| 1646 | other->sk_data_ready(other); |
| 1647 | sock_put(other); |
| 1648 | return 0; |
| 1649 | |
| 1650 | out_unlock: |
| 1651 | if (other) |
| 1652 | unix_state_unlock(other); |
| 1653 | |
| 1654 | out: |
| 1655 | kfree_skb(skb); |
| 1656 | if (newsk) |
| 1657 | unix_release_sock(newsk, 0); |
| 1658 | if (other) |
| 1659 | sock_put(other); |
| 1660 | return err; |
| 1661 | } |
| 1662 | |
| 1663 | static int unix_socketpair(struct socket *socka, struct socket *sockb) |
| 1664 | { |
| 1665 | struct sock *ska = socka->sk, *skb = sockb->sk; |
| 1666 | |
| 1667 | /* Join our sockets back to back */ |
| 1668 | sock_hold(ska); |
| 1669 | sock_hold(skb); |
| 1670 | unix_peer(ska) = skb; |
| 1671 | unix_peer(skb) = ska; |
| 1672 | init_peercred(ska); |
| 1673 | init_peercred(skb); |
| 1674 | |
| 1675 | ska->sk_state = TCP_ESTABLISHED; |
| 1676 | skb->sk_state = TCP_ESTABLISHED; |
| 1677 | socka->state = SS_CONNECTED; |
| 1678 | sockb->state = SS_CONNECTED; |
| 1679 | return 0; |
| 1680 | } |
| 1681 | |
| 1682 | static void unix_sock_inherit_flags(const struct socket *old, |
| 1683 | struct socket *new) |
| 1684 | { |
| 1685 | if (test_bit(SOCK_PASSCRED, &old->flags)) |
| 1686 | set_bit(SOCK_PASSCRED, &new->flags); |
| 1687 | if (test_bit(SOCK_PASSPIDFD, &old->flags)) |
| 1688 | set_bit(SOCK_PASSPIDFD, &new->flags); |
| 1689 | if (test_bit(SOCK_PASSSEC, &old->flags)) |
| 1690 | set_bit(SOCK_PASSSEC, &new->flags); |
| 1691 | } |
| 1692 | |
| 1693 | static int unix_accept(struct socket *sock, struct socket *newsock, int flags, |
| 1694 | bool kern) |
| 1695 | { |
| 1696 | struct sock *sk = sock->sk; |
| 1697 | struct sock *tsk; |
| 1698 | struct sk_buff *skb; |
| 1699 | int err; |
| 1700 | |
| 1701 | err = -EOPNOTSUPP; |
| 1702 | if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET) |
| 1703 | goto out; |
| 1704 | |
| 1705 | err = -EINVAL; |
| 1706 | if (sk->sk_state != TCP_LISTEN) |
| 1707 | goto out; |
| 1708 | |
| 1709 | /* If socket state is TCP_LISTEN it cannot change (for now...), |
| 1710 | * so that no locks are necessary. |
| 1711 | */ |
| 1712 | |
| 1713 | skb = skb_recv_datagram(sk, (flags & O_NONBLOCK) ? MSG_DONTWAIT : 0, |
| 1714 | &err); |
| 1715 | if (!skb) { |
| 1716 | /* This means receive shutdown. */ |
| 1717 | if (err == 0) |
| 1718 | err = -EINVAL; |
| 1719 | goto out; |
| 1720 | } |
| 1721 | |
| 1722 | tsk = skb->sk; |
| 1723 | skb_free_datagram(sk, skb); |
| 1724 | wake_up_interruptible(&unix_sk(sk)->peer_wait); |
| 1725 | |
| 1726 | /* attach accepted sock to socket */ |
| 1727 | unix_state_lock(tsk); |
| 1728 | newsock->state = SS_CONNECTED; |
| 1729 | unix_sock_inherit_flags(sock, newsock); |
| 1730 | sock_graft(tsk, newsock); |
| 1731 | unix_state_unlock(tsk); |
| 1732 | return 0; |
| 1733 | |
| 1734 | out: |
| 1735 | return err; |
| 1736 | } |
| 1737 | |
| 1738 | |
| 1739 | static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer) |
| 1740 | { |
| 1741 | struct sock *sk = sock->sk; |
| 1742 | struct unix_address *addr; |
| 1743 | DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr); |
| 1744 | int err = 0; |
| 1745 | |
| 1746 | if (peer) { |
| 1747 | sk = unix_peer_get(sk); |
| 1748 | |
| 1749 | err = -ENOTCONN; |
| 1750 | if (!sk) |
| 1751 | goto out; |
| 1752 | err = 0; |
| 1753 | } else { |
| 1754 | sock_hold(sk); |
| 1755 | } |
| 1756 | |
| 1757 | addr = smp_load_acquire(&unix_sk(sk)->addr); |
| 1758 | if (!addr) { |
| 1759 | sunaddr->sun_family = AF_UNIX; |
| 1760 | sunaddr->sun_path[0] = 0; |
| 1761 | err = offsetof(struct sockaddr_un, sun_path); |
| 1762 | } else { |
| 1763 | err = addr->len; |
| 1764 | memcpy(sunaddr, addr->name, addr->len); |
| 1765 | |
| 1766 | if (peer) |
| 1767 | BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err, |
| 1768 | CGROUP_UNIX_GETPEERNAME); |
| 1769 | else |
| 1770 | BPF_CGROUP_RUN_SA_PROG(sk, uaddr, &err, |
| 1771 | CGROUP_UNIX_GETSOCKNAME); |
| 1772 | } |
| 1773 | sock_put(sk); |
| 1774 | out: |
| 1775 | return err; |
| 1776 | } |
| 1777 | |
| 1778 | static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb) |
| 1779 | { |
| 1780 | scm->fp = scm_fp_dup(UNIXCB(skb).fp); |
| 1781 | |
| 1782 | /* |
| 1783 | * Garbage collection of unix sockets starts by selecting a set of |
| 1784 | * candidate sockets which have reference only from being in flight |
| 1785 | * (total_refs == inflight_refs). This condition is checked once during |
| 1786 | * the candidate collection phase, and candidates are marked as such, so |
| 1787 | * that non-candidates can later be ignored. While inflight_refs is |
| 1788 | * protected by unix_gc_lock, total_refs (file count) is not, hence this |
| 1789 | * is an instantaneous decision. |
| 1790 | * |
| 1791 | * Once a candidate, however, the socket must not be reinstalled into a |
| 1792 | * file descriptor while the garbage collection is in progress. |
| 1793 | * |
| 1794 | * If the above conditions are met, then the directed graph of |
| 1795 | * candidates (*) does not change while unix_gc_lock is held. |
| 1796 | * |
| 1797 | * Any operations that changes the file count through file descriptors |
| 1798 | * (dup, close, sendmsg) does not change the graph since candidates are |
| 1799 | * not installed in fds. |
| 1800 | * |
| 1801 | * Dequeing a candidate via recvmsg would install it into an fd, but |
| 1802 | * that takes unix_gc_lock to decrement the inflight count, so it's |
| 1803 | * serialized with garbage collection. |
| 1804 | * |
| 1805 | * MSG_PEEK is special in that it does not change the inflight count, |
| 1806 | * yet does install the socket into an fd. The following lock/unlock |
| 1807 | * pair is to ensure serialization with garbage collection. It must be |
| 1808 | * done between incrementing the file count and installing the file into |
| 1809 | * an fd. |
| 1810 | * |
| 1811 | * If garbage collection starts after the barrier provided by the |
| 1812 | * lock/unlock, then it will see the elevated refcount and not mark this |
| 1813 | * as a candidate. If a garbage collection is already in progress |
| 1814 | * before the file count was incremented, then the lock/unlock pair will |
| 1815 | * ensure that garbage collection is finished before progressing to |
| 1816 | * installing the fd. |
| 1817 | * |
| 1818 | * (*) A -> B where B is on the queue of A or B is on the queue of C |
| 1819 | * which is on the queue of listening socket A. |
| 1820 | */ |
| 1821 | spin_lock(&unix_gc_lock); |
| 1822 | spin_unlock(&unix_gc_lock); |
| 1823 | } |
| 1824 | |
| 1825 | static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds) |
| 1826 | { |
| 1827 | int err = 0; |
| 1828 | |
| 1829 | UNIXCB(skb).pid = get_pid(scm->pid); |
| 1830 | UNIXCB(skb).uid = scm->creds.uid; |
| 1831 | UNIXCB(skb).gid = scm->creds.gid; |
| 1832 | UNIXCB(skb).fp = NULL; |
| 1833 | unix_get_secdata(scm, skb); |
| 1834 | if (scm->fp && send_fds) |
| 1835 | err = unix_attach_fds(scm, skb); |
| 1836 | |
| 1837 | skb->destructor = unix_destruct_scm; |
| 1838 | return err; |
| 1839 | } |
| 1840 | |
| 1841 | static bool unix_passcred_enabled(const struct socket *sock, |
| 1842 | const struct sock *other) |
| 1843 | { |
| 1844 | return test_bit(SOCK_PASSCRED, &sock->flags) || |
| 1845 | test_bit(SOCK_PASSPIDFD, &sock->flags) || |
| 1846 | !other->sk_socket || |
| 1847 | test_bit(SOCK_PASSCRED, &other->sk_socket->flags) || |
| 1848 | test_bit(SOCK_PASSPIDFD, &other->sk_socket->flags); |
| 1849 | } |
| 1850 | |
| 1851 | /* |
| 1852 | * Some apps rely on write() giving SCM_CREDENTIALS |
| 1853 | * We include credentials if source or destination socket |
| 1854 | * asserted SOCK_PASSCRED. |
| 1855 | */ |
| 1856 | static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock, |
| 1857 | const struct sock *other) |
| 1858 | { |
| 1859 | if (UNIXCB(skb).pid) |
| 1860 | return; |
| 1861 | if (unix_passcred_enabled(sock, other)) { |
| 1862 | UNIXCB(skb).pid = get_pid(task_tgid(current)); |
| 1863 | current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid); |
| 1864 | } |
| 1865 | } |
| 1866 | |
| 1867 | static bool unix_skb_scm_eq(struct sk_buff *skb, |
| 1868 | struct scm_cookie *scm) |
| 1869 | { |
| 1870 | return UNIXCB(skb).pid == scm->pid && |
| 1871 | uid_eq(UNIXCB(skb).uid, scm->creds.uid) && |
| 1872 | gid_eq(UNIXCB(skb).gid, scm->creds.gid) && |
| 1873 | unix_secdata_eq(scm, skb); |
| 1874 | } |
| 1875 | |
| 1876 | static void scm_stat_add(struct sock *sk, struct sk_buff *skb) |
| 1877 | { |
| 1878 | struct scm_fp_list *fp = UNIXCB(skb).fp; |
| 1879 | struct unix_sock *u = unix_sk(sk); |
| 1880 | |
| 1881 | if (unlikely(fp && fp->count)) |
| 1882 | atomic_add(fp->count, &u->scm_stat.nr_fds); |
| 1883 | } |
| 1884 | |
| 1885 | static void scm_stat_del(struct sock *sk, struct sk_buff *skb) |
| 1886 | { |
| 1887 | struct scm_fp_list *fp = UNIXCB(skb).fp; |
| 1888 | struct unix_sock *u = unix_sk(sk); |
| 1889 | |
| 1890 | if (unlikely(fp && fp->count)) |
| 1891 | atomic_sub(fp->count, &u->scm_stat.nr_fds); |
| 1892 | } |
| 1893 | |
| 1894 | /* |
| 1895 | * Send AF_UNIX data. |
| 1896 | */ |
| 1897 | |
| 1898 | static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, |
| 1899 | size_t len) |
| 1900 | { |
| 1901 | DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name); |
| 1902 | struct sock *sk = sock->sk, *other = NULL; |
| 1903 | struct unix_sock *u = unix_sk(sk); |
| 1904 | struct scm_cookie scm; |
| 1905 | struct sk_buff *skb; |
| 1906 | int data_len = 0; |
| 1907 | int sk_locked; |
| 1908 | long timeo; |
| 1909 | int err; |
| 1910 | |
| 1911 | wait_for_unix_gc(); |
| 1912 | err = scm_send(sock, msg, &scm, false); |
| 1913 | if (err < 0) |
| 1914 | return err; |
| 1915 | |
| 1916 | err = -EOPNOTSUPP; |
| 1917 | if (msg->msg_flags&MSG_OOB) |
| 1918 | goto out; |
| 1919 | |
| 1920 | if (msg->msg_namelen) { |
| 1921 | err = unix_validate_addr(sunaddr, msg->msg_namelen); |
| 1922 | if (err) |
| 1923 | goto out; |
| 1924 | |
| 1925 | err = BPF_CGROUP_RUN_PROG_UNIX_SENDMSG_LOCK(sk, |
| 1926 | msg->msg_name, |
| 1927 | &msg->msg_namelen, |
| 1928 | NULL); |
| 1929 | if (err) |
| 1930 | goto out; |
| 1931 | } else { |
| 1932 | sunaddr = NULL; |
| 1933 | err = -ENOTCONN; |
| 1934 | other = unix_peer_get(sk); |
| 1935 | if (!other) |
| 1936 | goto out; |
| 1937 | } |
| 1938 | |
| 1939 | if ((test_bit(SOCK_PASSCRED, &sock->flags) || |
| 1940 | test_bit(SOCK_PASSPIDFD, &sock->flags)) && !u->addr) { |
| 1941 | err = unix_autobind(sk); |
| 1942 | if (err) |
| 1943 | goto out; |
| 1944 | } |
| 1945 | |
| 1946 | err = -EMSGSIZE; |
| 1947 | if (len > sk->sk_sndbuf - 32) |
| 1948 | goto out; |
| 1949 | |
| 1950 | if (len > SKB_MAX_ALLOC) { |
| 1951 | data_len = min_t(size_t, |
| 1952 | len - SKB_MAX_ALLOC, |
| 1953 | MAX_SKB_FRAGS * PAGE_SIZE); |
| 1954 | data_len = PAGE_ALIGN(data_len); |
| 1955 | |
| 1956 | BUILD_BUG_ON(SKB_MAX_ALLOC < PAGE_SIZE); |
| 1957 | } |
| 1958 | |
| 1959 | skb = sock_alloc_send_pskb(sk, len - data_len, data_len, |
| 1960 | msg->msg_flags & MSG_DONTWAIT, &err, |
| 1961 | PAGE_ALLOC_COSTLY_ORDER); |
| 1962 | if (skb == NULL) |
| 1963 | goto out; |
| 1964 | |
| 1965 | err = unix_scm_to_skb(&scm, skb, true); |
| 1966 | if (err < 0) |
| 1967 | goto out_free; |
| 1968 | |
| 1969 | skb_put(skb, len - data_len); |
| 1970 | skb->data_len = data_len; |
| 1971 | skb->len = len; |
| 1972 | err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len); |
| 1973 | if (err) |
| 1974 | goto out_free; |
| 1975 | |
| 1976 | timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); |
| 1977 | |
| 1978 | restart: |
| 1979 | if (!other) { |
| 1980 | err = -ECONNRESET; |
| 1981 | if (sunaddr == NULL) |
| 1982 | goto out_free; |
| 1983 | |
| 1984 | other = unix_find_other(sock_net(sk), sunaddr, msg->msg_namelen, |
| 1985 | sk->sk_type); |
| 1986 | if (IS_ERR(other)) { |
| 1987 | err = PTR_ERR(other); |
| 1988 | other = NULL; |
| 1989 | goto out_free; |
| 1990 | } |
| 1991 | } |
| 1992 | |
| 1993 | if (sk_filter(other, skb) < 0) { |
| 1994 | /* Toss the packet but do not return any error to the sender */ |
| 1995 | err = len; |
| 1996 | goto out_free; |
| 1997 | } |
| 1998 | |
| 1999 | sk_locked = 0; |
| 2000 | unix_state_lock(other); |
| 2001 | restart_locked: |
| 2002 | err = -EPERM; |
| 2003 | if (!unix_may_send(sk, other)) |
| 2004 | goto out_unlock; |
| 2005 | |
| 2006 | if (unlikely(sock_flag(other, SOCK_DEAD))) { |
| 2007 | /* |
| 2008 | * Check with 1003.1g - what should |
| 2009 | * datagram error |
| 2010 | */ |
| 2011 | unix_state_unlock(other); |
| 2012 | sock_put(other); |
| 2013 | |
| 2014 | if (!sk_locked) |
| 2015 | unix_state_lock(sk); |
| 2016 | |
| 2017 | err = 0; |
| 2018 | if (sk->sk_type == SOCK_SEQPACKET) { |
| 2019 | /* We are here only when racing with unix_release_sock() |
| 2020 | * is clearing @other. Never change state to TCP_CLOSE |
| 2021 | * unlike SOCK_DGRAM wants. |
| 2022 | */ |
| 2023 | unix_state_unlock(sk); |
| 2024 | err = -EPIPE; |
| 2025 | } else if (unix_peer(sk) == other) { |
| 2026 | unix_peer(sk) = NULL; |
| 2027 | unix_dgram_peer_wake_disconnect_wakeup(sk, other); |
| 2028 | |
| 2029 | sk->sk_state = TCP_CLOSE; |
| 2030 | unix_state_unlock(sk); |
| 2031 | |
| 2032 | unix_dgram_disconnected(sk, other); |
| 2033 | sock_put(other); |
| 2034 | err = -ECONNREFUSED; |
| 2035 | } else { |
| 2036 | unix_state_unlock(sk); |
| 2037 | } |
| 2038 | |
| 2039 | other = NULL; |
| 2040 | if (err) |
| 2041 | goto out_free; |
| 2042 | goto restart; |
| 2043 | } |
| 2044 | |
| 2045 | err = -EPIPE; |
| 2046 | if (other->sk_shutdown & RCV_SHUTDOWN) |
| 2047 | goto out_unlock; |
| 2048 | |
| 2049 | if (sk->sk_type != SOCK_SEQPACKET) { |
| 2050 | err = security_unix_may_send(sk->sk_socket, other->sk_socket); |
| 2051 | if (err) |
| 2052 | goto out_unlock; |
| 2053 | } |
| 2054 | |
| 2055 | /* other == sk && unix_peer(other) != sk if |
| 2056 | * - unix_peer(sk) == NULL, destination address bound to sk |
| 2057 | * - unix_peer(sk) == sk by time of get but disconnected before lock |
| 2058 | */ |
| 2059 | if (other != sk && |
| 2060 | unlikely(unix_peer(other) != sk && |
| 2061 | unix_recvq_full_lockless(other))) { |
| 2062 | if (timeo) { |
| 2063 | timeo = unix_wait_for_peer(other, timeo); |
| 2064 | |
| 2065 | err = sock_intr_errno(timeo); |
| 2066 | if (signal_pending(current)) |
| 2067 | goto out_free; |
| 2068 | |
| 2069 | goto restart; |
| 2070 | } |
| 2071 | |
| 2072 | if (!sk_locked) { |
| 2073 | unix_state_unlock(other); |
| 2074 | unix_state_double_lock(sk, other); |
| 2075 | } |
| 2076 | |
| 2077 | if (unix_peer(sk) != other || |
| 2078 | unix_dgram_peer_wake_me(sk, other)) { |
| 2079 | err = -EAGAIN; |
| 2080 | sk_locked = 1; |
| 2081 | goto out_unlock; |
| 2082 | } |
| 2083 | |
| 2084 | if (!sk_locked) { |
| 2085 | sk_locked = 1; |
| 2086 | goto restart_locked; |
| 2087 | } |
| 2088 | } |
| 2089 | |
| 2090 | if (unlikely(sk_locked)) |
| 2091 | unix_state_unlock(sk); |
| 2092 | |
| 2093 | if (sock_flag(other, SOCK_RCVTSTAMP)) |
| 2094 | __net_timestamp(skb); |
| 2095 | maybe_add_creds(skb, sock, other); |
| 2096 | scm_stat_add(other, skb); |
| 2097 | skb_queue_tail(&other->sk_receive_queue, skb); |
| 2098 | unix_state_unlock(other); |
| 2099 | other->sk_data_ready(other); |
| 2100 | sock_put(other); |
| 2101 | scm_destroy(&scm); |
| 2102 | return len; |
| 2103 | |
| 2104 | out_unlock: |
| 2105 | if (sk_locked) |
| 2106 | unix_state_unlock(sk); |
| 2107 | unix_state_unlock(other); |
| 2108 | out_free: |
| 2109 | kfree_skb(skb); |
| 2110 | out: |
| 2111 | if (other) |
| 2112 | sock_put(other); |
| 2113 | scm_destroy(&scm); |
| 2114 | return err; |
| 2115 | } |
| 2116 | |
| 2117 | /* We use paged skbs for stream sockets, and limit occupancy to 32768 |
| 2118 | * bytes, and a minimum of a full page. |
| 2119 | */ |
| 2120 | #define UNIX_SKB_FRAGS_SZ (PAGE_SIZE << get_order(32768)) |
| 2121 | |
| 2122 | #if IS_ENABLED(CONFIG_AF_UNIX_OOB) |
| 2123 | static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other, |
| 2124 | struct scm_cookie *scm, bool fds_sent) |
| 2125 | { |
| 2126 | struct unix_sock *ousk = unix_sk(other); |
| 2127 | struct sk_buff *skb; |
| 2128 | int err = 0; |
| 2129 | |
| 2130 | skb = sock_alloc_send_skb(sock->sk, 1, msg->msg_flags & MSG_DONTWAIT, &err); |
| 2131 | |
| 2132 | if (!skb) |
| 2133 | return err; |
| 2134 | |
| 2135 | err = unix_scm_to_skb(scm, skb, !fds_sent); |
| 2136 | if (err < 0) { |
| 2137 | kfree_skb(skb); |
| 2138 | return err; |
| 2139 | } |
| 2140 | skb_put(skb, 1); |
| 2141 | err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, 1); |
| 2142 | |
| 2143 | if (err) { |
| 2144 | kfree_skb(skb); |
| 2145 | return err; |
| 2146 | } |
| 2147 | |
| 2148 | unix_state_lock(other); |
| 2149 | |
| 2150 | if (sock_flag(other, SOCK_DEAD) || |
| 2151 | (other->sk_shutdown & RCV_SHUTDOWN)) { |
| 2152 | unix_state_unlock(other); |
| 2153 | kfree_skb(skb); |
| 2154 | return -EPIPE; |
| 2155 | } |
| 2156 | |
| 2157 | maybe_add_creds(skb, sock, other); |
| 2158 | skb_get(skb); |
| 2159 | |
| 2160 | if (ousk->oob_skb) |
| 2161 | consume_skb(ousk->oob_skb); |
| 2162 | |
| 2163 | WRITE_ONCE(ousk->oob_skb, skb); |
| 2164 | |
| 2165 | scm_stat_add(other, skb); |
| 2166 | skb_queue_tail(&other->sk_receive_queue, skb); |
| 2167 | sk_send_sigurg(other); |
| 2168 | unix_state_unlock(other); |
| 2169 | other->sk_data_ready(other); |
| 2170 | |
| 2171 | return err; |
| 2172 | } |
| 2173 | #endif |
| 2174 | |
| 2175 | static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, |
| 2176 | size_t len) |
| 2177 | { |
| 2178 | struct sock *sk = sock->sk; |
| 2179 | struct sock *other = NULL; |
| 2180 | int err, size; |
| 2181 | struct sk_buff *skb; |
| 2182 | int sent = 0; |
| 2183 | struct scm_cookie scm; |
| 2184 | bool fds_sent = false; |
| 2185 | int data_len; |
| 2186 | |
| 2187 | wait_for_unix_gc(); |
| 2188 | err = scm_send(sock, msg, &scm, false); |
| 2189 | if (err < 0) |
| 2190 | return err; |
| 2191 | |
| 2192 | err = -EOPNOTSUPP; |
| 2193 | if (msg->msg_flags & MSG_OOB) { |
| 2194 | #if IS_ENABLED(CONFIG_AF_UNIX_OOB) |
| 2195 | if (len) |
| 2196 | len--; |
| 2197 | else |
| 2198 | #endif |
| 2199 | goto out_err; |
| 2200 | } |
| 2201 | |
| 2202 | if (msg->msg_namelen) { |
| 2203 | err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP; |
| 2204 | goto out_err; |
| 2205 | } else { |
| 2206 | err = -ENOTCONN; |
| 2207 | other = unix_peer(sk); |
| 2208 | if (!other) |
| 2209 | goto out_err; |
| 2210 | } |
| 2211 | |
| 2212 | if (sk->sk_shutdown & SEND_SHUTDOWN) |
| 2213 | goto pipe_err; |
| 2214 | |
| 2215 | while (sent < len) { |
| 2216 | size = len - sent; |
| 2217 | |
| 2218 | if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) { |
| 2219 | skb = sock_alloc_send_pskb(sk, 0, 0, |
| 2220 | msg->msg_flags & MSG_DONTWAIT, |
| 2221 | &err, 0); |
| 2222 | } else { |
| 2223 | /* Keep two messages in the pipe so it schedules better */ |
| 2224 | size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64); |
| 2225 | |
| 2226 | /* allow fallback to order-0 allocations */ |
| 2227 | size = min_t(int, size, SKB_MAX_HEAD(0) + UNIX_SKB_FRAGS_SZ); |
| 2228 | |
| 2229 | data_len = max_t(int, 0, size - SKB_MAX_HEAD(0)); |
| 2230 | |
| 2231 | data_len = min_t(size_t, size, PAGE_ALIGN(data_len)); |
| 2232 | |
| 2233 | skb = sock_alloc_send_pskb(sk, size - data_len, data_len, |
| 2234 | msg->msg_flags & MSG_DONTWAIT, &err, |
| 2235 | get_order(UNIX_SKB_FRAGS_SZ)); |
| 2236 | } |
| 2237 | if (!skb) |
| 2238 | goto out_err; |
| 2239 | |
| 2240 | /* Only send the fds in the first buffer */ |
| 2241 | err = unix_scm_to_skb(&scm, skb, !fds_sent); |
| 2242 | if (err < 0) { |
| 2243 | kfree_skb(skb); |
| 2244 | goto out_err; |
| 2245 | } |
| 2246 | fds_sent = true; |
| 2247 | |
| 2248 | if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) { |
| 2249 | err = skb_splice_from_iter(skb, &msg->msg_iter, size, |
| 2250 | sk->sk_allocation); |
| 2251 | if (err < 0) { |
| 2252 | kfree_skb(skb); |
| 2253 | goto out_err; |
| 2254 | } |
| 2255 | size = err; |
| 2256 | refcount_add(size, &sk->sk_wmem_alloc); |
| 2257 | } else { |
| 2258 | skb_put(skb, size - data_len); |
| 2259 | skb->data_len = data_len; |
| 2260 | skb->len = size; |
| 2261 | err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size); |
| 2262 | if (err) { |
| 2263 | kfree_skb(skb); |
| 2264 | goto out_err; |
| 2265 | } |
| 2266 | } |
| 2267 | |
| 2268 | unix_state_lock(other); |
| 2269 | |
| 2270 | if (sock_flag(other, SOCK_DEAD) || |
| 2271 | (other->sk_shutdown & RCV_SHUTDOWN)) |
| 2272 | goto pipe_err_free; |
| 2273 | |
| 2274 | maybe_add_creds(skb, sock, other); |
| 2275 | scm_stat_add(other, skb); |
| 2276 | skb_queue_tail(&other->sk_receive_queue, skb); |
| 2277 | unix_state_unlock(other); |
| 2278 | other->sk_data_ready(other); |
| 2279 | sent += size; |
| 2280 | } |
| 2281 | |
| 2282 | #if IS_ENABLED(CONFIG_AF_UNIX_OOB) |
| 2283 | if (msg->msg_flags & MSG_OOB) { |
| 2284 | err = queue_oob(sock, msg, other, &scm, fds_sent); |
| 2285 | if (err) |
| 2286 | goto out_err; |
| 2287 | sent++; |
| 2288 | } |
| 2289 | #endif |
| 2290 | |
| 2291 | scm_destroy(&scm); |
| 2292 | |
| 2293 | return sent; |
| 2294 | |
| 2295 | pipe_err_free: |
| 2296 | unix_state_unlock(other); |
| 2297 | kfree_skb(skb); |
| 2298 | pipe_err: |
| 2299 | if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL)) |
| 2300 | send_sig(SIGPIPE, current, 0); |
| 2301 | err = -EPIPE; |
| 2302 | out_err: |
| 2303 | scm_destroy(&scm); |
| 2304 | return sent ? : err; |
| 2305 | } |
| 2306 | |
| 2307 | static int unix_seqpacket_sendmsg(struct socket *sock, struct msghdr *msg, |
| 2308 | size_t len) |
| 2309 | { |
| 2310 | int err; |
| 2311 | struct sock *sk = sock->sk; |
| 2312 | |
| 2313 | err = sock_error(sk); |
| 2314 | if (err) |
| 2315 | return err; |
| 2316 | |
| 2317 | if (sk->sk_state != TCP_ESTABLISHED) |
| 2318 | return -ENOTCONN; |
| 2319 | |
| 2320 | if (msg->msg_namelen) |
| 2321 | msg->msg_namelen = 0; |
| 2322 | |
| 2323 | return unix_dgram_sendmsg(sock, msg, len); |
| 2324 | } |
| 2325 | |
| 2326 | static int unix_seqpacket_recvmsg(struct socket *sock, struct msghdr *msg, |
| 2327 | size_t size, int flags) |
| 2328 | { |
| 2329 | struct sock *sk = sock->sk; |
| 2330 | |
| 2331 | if (sk->sk_state != TCP_ESTABLISHED) |
| 2332 | return -ENOTCONN; |
| 2333 | |
| 2334 | return unix_dgram_recvmsg(sock, msg, size, flags); |
| 2335 | } |
| 2336 | |
| 2337 | static void unix_copy_addr(struct msghdr *msg, struct sock *sk) |
| 2338 | { |
| 2339 | struct unix_address *addr = smp_load_acquire(&unix_sk(sk)->addr); |
| 2340 | |
| 2341 | if (addr) { |
| 2342 | msg->msg_namelen = addr->len; |
| 2343 | memcpy(msg->msg_name, addr->name, addr->len); |
| 2344 | } |
| 2345 | } |
| 2346 | |
| 2347 | int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, |
| 2348 | int flags) |
| 2349 | { |
| 2350 | struct scm_cookie scm; |
| 2351 | struct socket *sock = sk->sk_socket; |
| 2352 | struct unix_sock *u = unix_sk(sk); |
| 2353 | struct sk_buff *skb, *last; |
| 2354 | long timeo; |
| 2355 | int skip; |
| 2356 | int err; |
| 2357 | |
| 2358 | err = -EOPNOTSUPP; |
| 2359 | if (flags&MSG_OOB) |
| 2360 | goto out; |
| 2361 | |
| 2362 | timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); |
| 2363 | |
| 2364 | do { |
| 2365 | mutex_lock(&u->iolock); |
| 2366 | |
| 2367 | skip = sk_peek_offset(sk, flags); |
| 2368 | skb = __skb_try_recv_datagram(sk, &sk->sk_receive_queue, flags, |
| 2369 | &skip, &err, &last); |
| 2370 | if (skb) { |
| 2371 | if (!(flags & MSG_PEEK)) |
| 2372 | scm_stat_del(sk, skb); |
| 2373 | break; |
| 2374 | } |
| 2375 | |
| 2376 | mutex_unlock(&u->iolock); |
| 2377 | |
| 2378 | if (err != -EAGAIN) |
| 2379 | break; |
| 2380 | } while (timeo && |
| 2381 | !__skb_wait_for_more_packets(sk, &sk->sk_receive_queue, |
| 2382 | &err, &timeo, last)); |
| 2383 | |
| 2384 | if (!skb) { /* implies iolock unlocked */ |
| 2385 | unix_state_lock(sk); |
| 2386 | /* Signal EOF on disconnected non-blocking SEQPACKET socket. */ |
| 2387 | if (sk->sk_type == SOCK_SEQPACKET && err == -EAGAIN && |
| 2388 | (sk->sk_shutdown & RCV_SHUTDOWN)) |
| 2389 | err = 0; |
| 2390 | unix_state_unlock(sk); |
| 2391 | goto out; |
| 2392 | } |
| 2393 | |
| 2394 | if (wq_has_sleeper(&u->peer_wait)) |
| 2395 | wake_up_interruptible_sync_poll(&u->peer_wait, |
| 2396 | EPOLLOUT | EPOLLWRNORM | |
| 2397 | EPOLLWRBAND); |
| 2398 | |
| 2399 | if (msg->msg_name) { |
| 2400 | unix_copy_addr(msg, skb->sk); |
| 2401 | |
| 2402 | BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk, |
| 2403 | msg->msg_name, |
| 2404 | &msg->msg_namelen); |
| 2405 | } |
| 2406 | |
| 2407 | if (size > skb->len - skip) |
| 2408 | size = skb->len - skip; |
| 2409 | else if (size < skb->len - skip) |
| 2410 | msg->msg_flags |= MSG_TRUNC; |
| 2411 | |
| 2412 | err = skb_copy_datagram_msg(skb, skip, msg, size); |
| 2413 | if (err) |
| 2414 | goto out_free; |
| 2415 | |
| 2416 | if (sock_flag(sk, SOCK_RCVTSTAMP)) |
| 2417 | __sock_recv_timestamp(msg, sk, skb); |
| 2418 | |
| 2419 | memset(&scm, 0, sizeof(scm)); |
| 2420 | |
| 2421 | scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); |
| 2422 | unix_set_secdata(&scm, skb); |
| 2423 | |
| 2424 | if (!(flags & MSG_PEEK)) { |
| 2425 | if (UNIXCB(skb).fp) |
| 2426 | unix_detach_fds(&scm, skb); |
| 2427 | |
| 2428 | sk_peek_offset_bwd(sk, skb->len); |
| 2429 | } else { |
| 2430 | /* It is questionable: on PEEK we could: |
| 2431 | - do not return fds - good, but too simple 8) |
| 2432 | - return fds, and do not return them on read (old strategy, |
| 2433 | apparently wrong) |
| 2434 | - clone fds (I chose it for now, it is the most universal |
| 2435 | solution) |
| 2436 | |
| 2437 | POSIX 1003.1g does not actually define this clearly |
| 2438 | at all. POSIX 1003.1g doesn't define a lot of things |
| 2439 | clearly however! |
| 2440 | |
| 2441 | */ |
| 2442 | |
| 2443 | sk_peek_offset_fwd(sk, size); |
| 2444 | |
| 2445 | if (UNIXCB(skb).fp) |
| 2446 | unix_peek_fds(&scm, skb); |
| 2447 | } |
| 2448 | err = (flags & MSG_TRUNC) ? skb->len - skip : size; |
| 2449 | |
| 2450 | scm_recv_unix(sock, msg, &scm, flags); |
| 2451 | |
| 2452 | out_free: |
| 2453 | skb_free_datagram(sk, skb); |
| 2454 | mutex_unlock(&u->iolock); |
| 2455 | out: |
| 2456 | return err; |
| 2457 | } |
| 2458 | |
| 2459 | static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, |
| 2460 | int flags) |
| 2461 | { |
| 2462 | struct sock *sk = sock->sk; |
| 2463 | |
| 2464 | #ifdef CONFIG_BPF_SYSCALL |
| 2465 | const struct proto *prot = READ_ONCE(sk->sk_prot); |
| 2466 | |
| 2467 | if (prot != &unix_dgram_proto) |
| 2468 | return prot->recvmsg(sk, msg, size, flags, NULL); |
| 2469 | #endif |
| 2470 | return __unix_dgram_recvmsg(sk, msg, size, flags); |
| 2471 | } |
| 2472 | |
| 2473 | static int unix_read_skb(struct sock *sk, skb_read_actor_t recv_actor) |
| 2474 | { |
| 2475 | struct unix_sock *u = unix_sk(sk); |
| 2476 | struct sk_buff *skb; |
| 2477 | int err; |
| 2478 | |
| 2479 | mutex_lock(&u->iolock); |
| 2480 | skb = skb_recv_datagram(sk, MSG_DONTWAIT, &err); |
| 2481 | mutex_unlock(&u->iolock); |
| 2482 | if (!skb) |
| 2483 | return err; |
| 2484 | |
| 2485 | return recv_actor(sk, skb); |
| 2486 | } |
| 2487 | |
| 2488 | /* |
| 2489 | * Sleep until more data has arrived. But check for races.. |
| 2490 | */ |
| 2491 | static long unix_stream_data_wait(struct sock *sk, long timeo, |
| 2492 | struct sk_buff *last, unsigned int last_len, |
| 2493 | bool freezable) |
| 2494 | { |
| 2495 | unsigned int state = TASK_INTERRUPTIBLE | freezable * TASK_FREEZABLE; |
| 2496 | struct sk_buff *tail; |
| 2497 | DEFINE_WAIT(wait); |
| 2498 | |
| 2499 | unix_state_lock(sk); |
| 2500 | |
| 2501 | for (;;) { |
| 2502 | prepare_to_wait(sk_sleep(sk), &wait, state); |
| 2503 | |
| 2504 | tail = skb_peek_tail(&sk->sk_receive_queue); |
| 2505 | if (tail != last || |
| 2506 | (tail && tail->len != last_len) || |
| 2507 | sk->sk_err || |
| 2508 | (sk->sk_shutdown & RCV_SHUTDOWN) || |
| 2509 | signal_pending(current) || |
| 2510 | !timeo) |
| 2511 | break; |
| 2512 | |
| 2513 | sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); |
| 2514 | unix_state_unlock(sk); |
| 2515 | timeo = schedule_timeout(timeo); |
| 2516 | unix_state_lock(sk); |
| 2517 | |
| 2518 | if (sock_flag(sk, SOCK_DEAD)) |
| 2519 | break; |
| 2520 | |
| 2521 | sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); |
| 2522 | } |
| 2523 | |
| 2524 | finish_wait(sk_sleep(sk), &wait); |
| 2525 | unix_state_unlock(sk); |
| 2526 | return timeo; |
| 2527 | } |
| 2528 | |
| 2529 | static unsigned int unix_skb_len(const struct sk_buff *skb) |
| 2530 | { |
| 2531 | return skb->len - UNIXCB(skb).consumed; |
| 2532 | } |
| 2533 | |
| 2534 | struct unix_stream_read_state { |
| 2535 | int (*recv_actor)(struct sk_buff *, int, int, |
| 2536 | struct unix_stream_read_state *); |
| 2537 | struct socket *socket; |
| 2538 | struct msghdr *msg; |
| 2539 | struct pipe_inode_info *pipe; |
| 2540 | size_t size; |
| 2541 | int flags; |
| 2542 | unsigned int splice_flags; |
| 2543 | }; |
| 2544 | |
| 2545 | #if IS_ENABLED(CONFIG_AF_UNIX_OOB) |
| 2546 | static int unix_stream_recv_urg(struct unix_stream_read_state *state) |
| 2547 | { |
| 2548 | struct socket *sock = state->socket; |
| 2549 | struct sock *sk = sock->sk; |
| 2550 | struct unix_sock *u = unix_sk(sk); |
| 2551 | int chunk = 1; |
| 2552 | struct sk_buff *oob_skb; |
| 2553 | |
| 2554 | mutex_lock(&u->iolock); |
| 2555 | unix_state_lock(sk); |
| 2556 | |
| 2557 | if (sock_flag(sk, SOCK_URGINLINE) || !u->oob_skb) { |
| 2558 | unix_state_unlock(sk); |
| 2559 | mutex_unlock(&u->iolock); |
| 2560 | return -EINVAL; |
| 2561 | } |
| 2562 | |
| 2563 | oob_skb = u->oob_skb; |
| 2564 | |
| 2565 | if (!(state->flags & MSG_PEEK)) |
| 2566 | WRITE_ONCE(u->oob_skb, NULL); |
| 2567 | else |
| 2568 | skb_get(oob_skb); |
| 2569 | unix_state_unlock(sk); |
| 2570 | |
| 2571 | chunk = state->recv_actor(oob_skb, 0, chunk, state); |
| 2572 | |
| 2573 | if (!(state->flags & MSG_PEEK)) |
| 2574 | UNIXCB(oob_skb).consumed += 1; |
| 2575 | |
| 2576 | consume_skb(oob_skb); |
| 2577 | |
| 2578 | mutex_unlock(&u->iolock); |
| 2579 | |
| 2580 | if (chunk < 0) |
| 2581 | return -EFAULT; |
| 2582 | |
| 2583 | state->msg->msg_flags |= MSG_OOB; |
| 2584 | return 1; |
| 2585 | } |
| 2586 | |
| 2587 | static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk, |
| 2588 | int flags, int copied) |
| 2589 | { |
| 2590 | struct unix_sock *u = unix_sk(sk); |
| 2591 | |
| 2592 | if (!unix_skb_len(skb) && !(flags & MSG_PEEK)) { |
| 2593 | skb_unlink(skb, &sk->sk_receive_queue); |
| 2594 | consume_skb(skb); |
| 2595 | skb = NULL; |
| 2596 | } else { |
| 2597 | if (skb == u->oob_skb) { |
| 2598 | if (copied) { |
| 2599 | skb = NULL; |
| 2600 | } else if (sock_flag(sk, SOCK_URGINLINE)) { |
| 2601 | if (!(flags & MSG_PEEK)) { |
| 2602 | WRITE_ONCE(u->oob_skb, NULL); |
| 2603 | consume_skb(skb); |
| 2604 | } |
| 2605 | } else if (!(flags & MSG_PEEK)) { |
| 2606 | skb_unlink(skb, &sk->sk_receive_queue); |
| 2607 | consume_skb(skb); |
| 2608 | skb = skb_peek(&sk->sk_receive_queue); |
| 2609 | } |
| 2610 | } |
| 2611 | } |
| 2612 | return skb; |
| 2613 | } |
| 2614 | #endif |
| 2615 | |
| 2616 | static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor) |
| 2617 | { |
| 2618 | if (unlikely(sk->sk_state != TCP_ESTABLISHED)) |
| 2619 | return -ENOTCONN; |
| 2620 | |
| 2621 | return unix_read_skb(sk, recv_actor); |
| 2622 | } |
| 2623 | |
| 2624 | static int unix_stream_read_generic(struct unix_stream_read_state *state, |
| 2625 | bool freezable) |
| 2626 | { |
| 2627 | struct scm_cookie scm; |
| 2628 | struct socket *sock = state->socket; |
| 2629 | struct sock *sk = sock->sk; |
| 2630 | struct unix_sock *u = unix_sk(sk); |
| 2631 | int copied = 0; |
| 2632 | int flags = state->flags; |
| 2633 | int noblock = flags & MSG_DONTWAIT; |
| 2634 | bool check_creds = false; |
| 2635 | int target; |
| 2636 | int err = 0; |
| 2637 | long timeo; |
| 2638 | int skip; |
| 2639 | size_t size = state->size; |
| 2640 | unsigned int last_len; |
| 2641 | |
| 2642 | if (unlikely(sk->sk_state != TCP_ESTABLISHED)) { |
| 2643 | err = -EINVAL; |
| 2644 | goto out; |
| 2645 | } |
| 2646 | |
| 2647 | if (unlikely(flags & MSG_OOB)) { |
| 2648 | err = -EOPNOTSUPP; |
| 2649 | #if IS_ENABLED(CONFIG_AF_UNIX_OOB) |
| 2650 | err = unix_stream_recv_urg(state); |
| 2651 | #endif |
| 2652 | goto out; |
| 2653 | } |
| 2654 | |
| 2655 | target = sock_rcvlowat(sk, flags & MSG_WAITALL, size); |
| 2656 | timeo = sock_rcvtimeo(sk, noblock); |
| 2657 | |
| 2658 | memset(&scm, 0, sizeof(scm)); |
| 2659 | |
| 2660 | /* Lock the socket to prevent queue disordering |
| 2661 | * while sleeps in memcpy_tomsg |
| 2662 | */ |
| 2663 | mutex_lock(&u->iolock); |
| 2664 | |
| 2665 | skip = max(sk_peek_offset(sk, flags), 0); |
| 2666 | |
| 2667 | do { |
| 2668 | int chunk; |
| 2669 | bool drop_skb; |
| 2670 | struct sk_buff *skb, *last; |
| 2671 | |
| 2672 | redo: |
| 2673 | unix_state_lock(sk); |
| 2674 | if (sock_flag(sk, SOCK_DEAD)) { |
| 2675 | err = -ECONNRESET; |
| 2676 | goto unlock; |
| 2677 | } |
| 2678 | last = skb = skb_peek(&sk->sk_receive_queue); |
| 2679 | last_len = last ? last->len : 0; |
| 2680 | |
| 2681 | #if IS_ENABLED(CONFIG_AF_UNIX_OOB) |
| 2682 | if (skb) { |
| 2683 | skb = manage_oob(skb, sk, flags, copied); |
| 2684 | if (!skb) { |
| 2685 | unix_state_unlock(sk); |
| 2686 | if (copied) |
| 2687 | break; |
| 2688 | goto redo; |
| 2689 | } |
| 2690 | } |
| 2691 | #endif |
| 2692 | again: |
| 2693 | if (skb == NULL) { |
| 2694 | if (copied >= target) |
| 2695 | goto unlock; |
| 2696 | |
| 2697 | /* |
| 2698 | * POSIX 1003.1g mandates this order. |
| 2699 | */ |
| 2700 | |
| 2701 | err = sock_error(sk); |
| 2702 | if (err) |
| 2703 | goto unlock; |
| 2704 | if (sk->sk_shutdown & RCV_SHUTDOWN) |
| 2705 | goto unlock; |
| 2706 | |
| 2707 | unix_state_unlock(sk); |
| 2708 | if (!timeo) { |
| 2709 | err = -EAGAIN; |
| 2710 | break; |
| 2711 | } |
| 2712 | |
| 2713 | mutex_unlock(&u->iolock); |
| 2714 | |
| 2715 | timeo = unix_stream_data_wait(sk, timeo, last, |
| 2716 | last_len, freezable); |
| 2717 | |
| 2718 | if (signal_pending(current)) { |
| 2719 | err = sock_intr_errno(timeo); |
| 2720 | scm_destroy(&scm); |
| 2721 | goto out; |
| 2722 | } |
| 2723 | |
| 2724 | mutex_lock(&u->iolock); |
| 2725 | goto redo; |
| 2726 | unlock: |
| 2727 | unix_state_unlock(sk); |
| 2728 | break; |
| 2729 | } |
| 2730 | |
| 2731 | while (skip >= unix_skb_len(skb)) { |
| 2732 | skip -= unix_skb_len(skb); |
| 2733 | last = skb; |
| 2734 | last_len = skb->len; |
| 2735 | skb = skb_peek_next(skb, &sk->sk_receive_queue); |
| 2736 | if (!skb) |
| 2737 | goto again; |
| 2738 | } |
| 2739 | |
| 2740 | unix_state_unlock(sk); |
| 2741 | |
| 2742 | if (check_creds) { |
| 2743 | /* Never glue messages from different writers */ |
| 2744 | if (!unix_skb_scm_eq(skb, &scm)) |
| 2745 | break; |
| 2746 | } else if (test_bit(SOCK_PASSCRED, &sock->flags) || |
| 2747 | test_bit(SOCK_PASSPIDFD, &sock->flags)) { |
| 2748 | /* Copy credentials */ |
| 2749 | scm_set_cred(&scm, UNIXCB(skb).pid, UNIXCB(skb).uid, UNIXCB(skb).gid); |
| 2750 | unix_set_secdata(&scm, skb); |
| 2751 | check_creds = true; |
| 2752 | } |
| 2753 | |
| 2754 | /* Copy address just once */ |
| 2755 | if (state->msg && state->msg->msg_name) { |
| 2756 | DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, |
| 2757 | state->msg->msg_name); |
| 2758 | unix_copy_addr(state->msg, skb->sk); |
| 2759 | |
| 2760 | BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk, |
| 2761 | state->msg->msg_name, |
| 2762 | &state->msg->msg_namelen); |
| 2763 | |
| 2764 | sunaddr = NULL; |
| 2765 | } |
| 2766 | |
| 2767 | chunk = min_t(unsigned int, unix_skb_len(skb) - skip, size); |
| 2768 | skb_get(skb); |
| 2769 | chunk = state->recv_actor(skb, skip, chunk, state); |
| 2770 | drop_skb = !unix_skb_len(skb); |
| 2771 | /* skb is only safe to use if !drop_skb */ |
| 2772 | consume_skb(skb); |
| 2773 | if (chunk < 0) { |
| 2774 | if (copied == 0) |
| 2775 | copied = -EFAULT; |
| 2776 | break; |
| 2777 | } |
| 2778 | copied += chunk; |
| 2779 | size -= chunk; |
| 2780 | |
| 2781 | if (drop_skb) { |
| 2782 | /* the skb was touched by a concurrent reader; |
| 2783 | * we should not expect anything from this skb |
| 2784 | * anymore and assume it invalid - we can be |
| 2785 | * sure it was dropped from the socket queue |
| 2786 | * |
| 2787 | * let's report a short read |
| 2788 | */ |
| 2789 | err = 0; |
| 2790 | break; |
| 2791 | } |
| 2792 | |
| 2793 | /* Mark read part of skb as used */ |
| 2794 | if (!(flags & MSG_PEEK)) { |
| 2795 | UNIXCB(skb).consumed += chunk; |
| 2796 | |
| 2797 | sk_peek_offset_bwd(sk, chunk); |
| 2798 | |
| 2799 | if (UNIXCB(skb).fp) { |
| 2800 | scm_stat_del(sk, skb); |
| 2801 | unix_detach_fds(&scm, skb); |
| 2802 | } |
| 2803 | |
| 2804 | if (unix_skb_len(skb)) |
| 2805 | break; |
| 2806 | |
| 2807 | skb_unlink(skb, &sk->sk_receive_queue); |
| 2808 | consume_skb(skb); |
| 2809 | |
| 2810 | if (scm.fp) |
| 2811 | break; |
| 2812 | } else { |
| 2813 | /* It is questionable, see note in unix_dgram_recvmsg. |
| 2814 | */ |
| 2815 | if (UNIXCB(skb).fp) |
| 2816 | unix_peek_fds(&scm, skb); |
| 2817 | |
| 2818 | sk_peek_offset_fwd(sk, chunk); |
| 2819 | |
| 2820 | if (UNIXCB(skb).fp) |
| 2821 | break; |
| 2822 | |
| 2823 | skip = 0; |
| 2824 | last = skb; |
| 2825 | last_len = skb->len; |
| 2826 | unix_state_lock(sk); |
| 2827 | skb = skb_peek_next(skb, &sk->sk_receive_queue); |
| 2828 | if (skb) |
| 2829 | goto again; |
| 2830 | unix_state_unlock(sk); |
| 2831 | break; |
| 2832 | } |
| 2833 | } while (size); |
| 2834 | |
| 2835 | mutex_unlock(&u->iolock); |
| 2836 | if (state->msg) |
| 2837 | scm_recv_unix(sock, state->msg, &scm, flags); |
| 2838 | else |
| 2839 | scm_destroy(&scm); |
| 2840 | out: |
| 2841 | return copied ? : err; |
| 2842 | } |
| 2843 | |
| 2844 | static int unix_stream_read_actor(struct sk_buff *skb, |
| 2845 | int skip, int chunk, |
| 2846 | struct unix_stream_read_state *state) |
| 2847 | { |
| 2848 | int ret; |
| 2849 | |
| 2850 | ret = skb_copy_datagram_msg(skb, UNIXCB(skb).consumed + skip, |
| 2851 | state->msg, chunk); |
| 2852 | return ret ?: chunk; |
| 2853 | } |
| 2854 | |
| 2855 | int __unix_stream_recvmsg(struct sock *sk, struct msghdr *msg, |
| 2856 | size_t size, int flags) |
| 2857 | { |
| 2858 | struct unix_stream_read_state state = { |
| 2859 | .recv_actor = unix_stream_read_actor, |
| 2860 | .socket = sk->sk_socket, |
| 2861 | .msg = msg, |
| 2862 | .size = size, |
| 2863 | .flags = flags |
| 2864 | }; |
| 2865 | |
| 2866 | return unix_stream_read_generic(&state, true); |
| 2867 | } |
| 2868 | |
| 2869 | static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg, |
| 2870 | size_t size, int flags) |
| 2871 | { |
| 2872 | struct unix_stream_read_state state = { |
| 2873 | .recv_actor = unix_stream_read_actor, |
| 2874 | .socket = sock, |
| 2875 | .msg = msg, |
| 2876 | .size = size, |
| 2877 | .flags = flags |
| 2878 | }; |
| 2879 | |
| 2880 | #ifdef CONFIG_BPF_SYSCALL |
| 2881 | struct sock *sk = sock->sk; |
| 2882 | const struct proto *prot = READ_ONCE(sk->sk_prot); |
| 2883 | |
| 2884 | if (prot != &unix_stream_proto) |
| 2885 | return prot->recvmsg(sk, msg, size, flags, NULL); |
| 2886 | #endif |
| 2887 | return unix_stream_read_generic(&state, true); |
| 2888 | } |
| 2889 | |
| 2890 | static int unix_stream_splice_actor(struct sk_buff *skb, |
| 2891 | int skip, int chunk, |
| 2892 | struct unix_stream_read_state *state) |
| 2893 | { |
| 2894 | return skb_splice_bits(skb, state->socket->sk, |
| 2895 | UNIXCB(skb).consumed + skip, |
| 2896 | state->pipe, chunk, state->splice_flags); |
| 2897 | } |
| 2898 | |
| 2899 | static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos, |
| 2900 | struct pipe_inode_info *pipe, |
| 2901 | size_t size, unsigned int flags) |
| 2902 | { |
| 2903 | struct unix_stream_read_state state = { |
| 2904 | .recv_actor = unix_stream_splice_actor, |
| 2905 | .socket = sock, |
| 2906 | .pipe = pipe, |
| 2907 | .size = size, |
| 2908 | .splice_flags = flags, |
| 2909 | }; |
| 2910 | |
| 2911 | if (unlikely(*ppos)) |
| 2912 | return -ESPIPE; |
| 2913 | |
| 2914 | if (sock->file->f_flags & O_NONBLOCK || |
| 2915 | flags & SPLICE_F_NONBLOCK) |
| 2916 | state.flags = MSG_DONTWAIT; |
| 2917 | |
| 2918 | return unix_stream_read_generic(&state, false); |
| 2919 | } |
| 2920 | |
| 2921 | static int unix_shutdown(struct socket *sock, int mode) |
| 2922 | { |
| 2923 | struct sock *sk = sock->sk; |
| 2924 | struct sock *other; |
| 2925 | |
| 2926 | if (mode < SHUT_RD || mode > SHUT_RDWR) |
| 2927 | return -EINVAL; |
| 2928 | /* This maps: |
| 2929 | * SHUT_RD (0) -> RCV_SHUTDOWN (1) |
| 2930 | * SHUT_WR (1) -> SEND_SHUTDOWN (2) |
| 2931 | * SHUT_RDWR (2) -> SHUTDOWN_MASK (3) |
| 2932 | */ |
| 2933 | ++mode; |
| 2934 | |
| 2935 | unix_state_lock(sk); |
| 2936 | WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | mode); |
| 2937 | other = unix_peer(sk); |
| 2938 | if (other) |
| 2939 | sock_hold(other); |
| 2940 | unix_state_unlock(sk); |
| 2941 | sk->sk_state_change(sk); |
| 2942 | |
| 2943 | if (other && |
| 2944 | (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET)) { |
| 2945 | |
| 2946 | int peer_mode = 0; |
| 2947 | const struct proto *prot = READ_ONCE(other->sk_prot); |
| 2948 | |
| 2949 | if (prot->unhash) |
| 2950 | prot->unhash(other); |
| 2951 | if (mode&RCV_SHUTDOWN) |
| 2952 | peer_mode |= SEND_SHUTDOWN; |
| 2953 | if (mode&SEND_SHUTDOWN) |
| 2954 | peer_mode |= RCV_SHUTDOWN; |
| 2955 | unix_state_lock(other); |
| 2956 | WRITE_ONCE(other->sk_shutdown, other->sk_shutdown | peer_mode); |
| 2957 | unix_state_unlock(other); |
| 2958 | other->sk_state_change(other); |
| 2959 | if (peer_mode == SHUTDOWN_MASK) |
| 2960 | sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP); |
| 2961 | else if (peer_mode & RCV_SHUTDOWN) |
| 2962 | sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN); |
| 2963 | } |
| 2964 | if (other) |
| 2965 | sock_put(other); |
| 2966 | |
| 2967 | return 0; |
| 2968 | } |
| 2969 | |
| 2970 | long unix_inq_len(struct sock *sk) |
| 2971 | { |
| 2972 | struct sk_buff *skb; |
| 2973 | long amount = 0; |
| 2974 | |
| 2975 | if (sk->sk_state == TCP_LISTEN) |
| 2976 | return -EINVAL; |
| 2977 | |
| 2978 | spin_lock(&sk->sk_receive_queue.lock); |
| 2979 | if (sk->sk_type == SOCK_STREAM || |
| 2980 | sk->sk_type == SOCK_SEQPACKET) { |
| 2981 | skb_queue_walk(&sk->sk_receive_queue, skb) |
| 2982 | amount += unix_skb_len(skb); |
| 2983 | } else { |
| 2984 | skb = skb_peek(&sk->sk_receive_queue); |
| 2985 | if (skb) |
| 2986 | amount = skb->len; |
| 2987 | } |
| 2988 | spin_unlock(&sk->sk_receive_queue.lock); |
| 2989 | |
| 2990 | return amount; |
| 2991 | } |
| 2992 | EXPORT_SYMBOL_GPL(unix_inq_len); |
| 2993 | |
| 2994 | long unix_outq_len(struct sock *sk) |
| 2995 | { |
| 2996 | return sk_wmem_alloc_get(sk); |
| 2997 | } |
| 2998 | EXPORT_SYMBOL_GPL(unix_outq_len); |
| 2999 | |
| 3000 | static int unix_open_file(struct sock *sk) |
| 3001 | { |
| 3002 | struct path path; |
| 3003 | struct file *f; |
| 3004 | int fd; |
| 3005 | |
| 3006 | if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) |
| 3007 | return -EPERM; |
| 3008 | |
| 3009 | if (!smp_load_acquire(&unix_sk(sk)->addr)) |
| 3010 | return -ENOENT; |
| 3011 | |
| 3012 | path = unix_sk(sk)->path; |
| 3013 | if (!path.dentry) |
| 3014 | return -ENOENT; |
| 3015 | |
| 3016 | path_get(&path); |
| 3017 | |
| 3018 | fd = get_unused_fd_flags(O_CLOEXEC); |
| 3019 | if (fd < 0) |
| 3020 | goto out; |
| 3021 | |
| 3022 | f = dentry_open(&path, O_PATH, current_cred()); |
| 3023 | if (IS_ERR(f)) { |
| 3024 | put_unused_fd(fd); |
| 3025 | fd = PTR_ERR(f); |
| 3026 | goto out; |
| 3027 | } |
| 3028 | |
| 3029 | fd_install(fd, f); |
| 3030 | out: |
| 3031 | path_put(&path); |
| 3032 | |
| 3033 | return fd; |
| 3034 | } |
| 3035 | |
| 3036 | static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) |
| 3037 | { |
| 3038 | struct sock *sk = sock->sk; |
| 3039 | long amount = 0; |
| 3040 | int err; |
| 3041 | |
| 3042 | switch (cmd) { |
| 3043 | case SIOCOUTQ: |
| 3044 | amount = unix_outq_len(sk); |
| 3045 | err = put_user(amount, (int __user *)arg); |
| 3046 | break; |
| 3047 | case SIOCINQ: |
| 3048 | amount = unix_inq_len(sk); |
| 3049 | if (amount < 0) |
| 3050 | err = amount; |
| 3051 | else |
| 3052 | err = put_user(amount, (int __user *)arg); |
| 3053 | break; |
| 3054 | case SIOCUNIXFILE: |
| 3055 | err = unix_open_file(sk); |
| 3056 | break; |
| 3057 | #if IS_ENABLED(CONFIG_AF_UNIX_OOB) |
| 3058 | case SIOCATMARK: |
| 3059 | { |
| 3060 | struct sk_buff *skb; |
| 3061 | int answ = 0; |
| 3062 | |
| 3063 | skb = skb_peek(&sk->sk_receive_queue); |
| 3064 | if (skb && skb == READ_ONCE(unix_sk(sk)->oob_skb)) |
| 3065 | answ = 1; |
| 3066 | err = put_user(answ, (int __user *)arg); |
| 3067 | } |
| 3068 | break; |
| 3069 | #endif |
| 3070 | default: |
| 3071 | err = -ENOIOCTLCMD; |
| 3072 | break; |
| 3073 | } |
| 3074 | return err; |
| 3075 | } |
| 3076 | |
| 3077 | #ifdef CONFIG_COMPAT |
| 3078 | static int unix_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) |
| 3079 | { |
| 3080 | return unix_ioctl(sock, cmd, (unsigned long)compat_ptr(arg)); |
| 3081 | } |
| 3082 | #endif |
| 3083 | |
| 3084 | static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wait) |
| 3085 | { |
| 3086 | struct sock *sk = sock->sk; |
| 3087 | __poll_t mask; |
| 3088 | u8 shutdown; |
| 3089 | |
| 3090 | sock_poll_wait(file, sock, wait); |
| 3091 | mask = 0; |
| 3092 | shutdown = READ_ONCE(sk->sk_shutdown); |
| 3093 | |
| 3094 | /* exceptional events? */ |
| 3095 | if (READ_ONCE(sk->sk_err)) |
| 3096 | mask |= EPOLLERR; |
| 3097 | if (shutdown == SHUTDOWN_MASK) |
| 3098 | mask |= EPOLLHUP; |
| 3099 | if (shutdown & RCV_SHUTDOWN) |
| 3100 | mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM; |
| 3101 | |
| 3102 | /* readable? */ |
| 3103 | if (!skb_queue_empty_lockless(&sk->sk_receive_queue)) |
| 3104 | mask |= EPOLLIN | EPOLLRDNORM; |
| 3105 | if (sk_is_readable(sk)) |
| 3106 | mask |= EPOLLIN | EPOLLRDNORM; |
| 3107 | #if IS_ENABLED(CONFIG_AF_UNIX_OOB) |
| 3108 | if (READ_ONCE(unix_sk(sk)->oob_skb)) |
| 3109 | mask |= EPOLLPRI; |
| 3110 | #endif |
| 3111 | |
| 3112 | /* Connection-based need to check for termination and startup */ |
| 3113 | if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && |
| 3114 | sk->sk_state == TCP_CLOSE) |
| 3115 | mask |= EPOLLHUP; |
| 3116 | |
| 3117 | /* |
| 3118 | * we set writable also when the other side has shut down the |
| 3119 | * connection. This prevents stuck sockets. |
| 3120 | */ |
| 3121 | if (unix_writable(sk)) |
| 3122 | mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND; |
| 3123 | |
| 3124 | return mask; |
| 3125 | } |
| 3126 | |
| 3127 | static __poll_t unix_dgram_poll(struct file *file, struct socket *sock, |
| 3128 | poll_table *wait) |
| 3129 | { |
| 3130 | struct sock *sk = sock->sk, *other; |
| 3131 | unsigned int writable; |
| 3132 | __poll_t mask; |
| 3133 | u8 shutdown; |
| 3134 | |
| 3135 | sock_poll_wait(file, sock, wait); |
| 3136 | mask = 0; |
| 3137 | shutdown = READ_ONCE(sk->sk_shutdown); |
| 3138 | |
| 3139 | /* exceptional events? */ |
| 3140 | if (READ_ONCE(sk->sk_err) || |
| 3141 | !skb_queue_empty_lockless(&sk->sk_error_queue)) |
| 3142 | mask |= EPOLLERR | |
| 3143 | (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0); |
| 3144 | |
| 3145 | if (shutdown & RCV_SHUTDOWN) |
| 3146 | mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM; |
| 3147 | if (shutdown == SHUTDOWN_MASK) |
| 3148 | mask |= EPOLLHUP; |
| 3149 | |
| 3150 | /* readable? */ |
| 3151 | if (!skb_queue_empty_lockless(&sk->sk_receive_queue)) |
| 3152 | mask |= EPOLLIN | EPOLLRDNORM; |
| 3153 | if (sk_is_readable(sk)) |
| 3154 | mask |= EPOLLIN | EPOLLRDNORM; |
| 3155 | |
| 3156 | /* Connection-based need to check for termination and startup */ |
| 3157 | if (sk->sk_type == SOCK_SEQPACKET) { |
| 3158 | if (sk->sk_state == TCP_CLOSE) |
| 3159 | mask |= EPOLLHUP; |
| 3160 | /* connection hasn't started yet? */ |
| 3161 | if (sk->sk_state == TCP_SYN_SENT) |
| 3162 | return mask; |
| 3163 | } |
| 3164 | |
| 3165 | /* No write status requested, avoid expensive OUT tests. */ |
| 3166 | if (!(poll_requested_events(wait) & (EPOLLWRBAND|EPOLLWRNORM|EPOLLOUT))) |
| 3167 | return mask; |
| 3168 | |
| 3169 | writable = unix_writable(sk); |
| 3170 | if (writable) { |
| 3171 | unix_state_lock(sk); |
| 3172 | |
| 3173 | other = unix_peer(sk); |
| 3174 | if (other && unix_peer(other) != sk && |
| 3175 | unix_recvq_full_lockless(other) && |
| 3176 | unix_dgram_peer_wake_me(sk, other)) |
| 3177 | writable = 0; |
| 3178 | |
| 3179 | unix_state_unlock(sk); |
| 3180 | } |
| 3181 | |
| 3182 | if (writable) |
| 3183 | mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND; |
| 3184 | else |
| 3185 | sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk); |
| 3186 | |
| 3187 | return mask; |
| 3188 | } |
| 3189 | |
| 3190 | #ifdef CONFIG_PROC_FS |
| 3191 | |
| 3192 | #define BUCKET_SPACE (BITS_PER_LONG - (UNIX_HASH_BITS + 1) - 1) |
| 3193 | |
| 3194 | #define get_bucket(x) ((x) >> BUCKET_SPACE) |
| 3195 | #define get_offset(x) ((x) & ((1UL << BUCKET_SPACE) - 1)) |
| 3196 | #define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o)) |
| 3197 | |
| 3198 | static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos) |
| 3199 | { |
| 3200 | unsigned long offset = get_offset(*pos); |
| 3201 | unsigned long bucket = get_bucket(*pos); |
| 3202 | unsigned long count = 0; |
| 3203 | struct sock *sk; |
| 3204 | |
| 3205 | for (sk = sk_head(&seq_file_net(seq)->unx.table.buckets[bucket]); |
| 3206 | sk; sk = sk_next(sk)) { |
| 3207 | if (++count == offset) |
| 3208 | break; |
| 3209 | } |
| 3210 | |
| 3211 | return sk; |
| 3212 | } |
| 3213 | |
| 3214 | static struct sock *unix_get_first(struct seq_file *seq, loff_t *pos) |
| 3215 | { |
| 3216 | unsigned long bucket = get_bucket(*pos); |
| 3217 | struct net *net = seq_file_net(seq); |
| 3218 | struct sock *sk; |
| 3219 | |
| 3220 | while (bucket < UNIX_HASH_SIZE) { |
| 3221 | spin_lock(&net->unx.table.locks[bucket]); |
| 3222 | |
| 3223 | sk = unix_from_bucket(seq, pos); |
| 3224 | if (sk) |
| 3225 | return sk; |
| 3226 | |
| 3227 | spin_unlock(&net->unx.table.locks[bucket]); |
| 3228 | |
| 3229 | *pos = set_bucket_offset(++bucket, 1); |
| 3230 | } |
| 3231 | |
| 3232 | return NULL; |
| 3233 | } |
| 3234 | |
| 3235 | static struct sock *unix_get_next(struct seq_file *seq, struct sock *sk, |
| 3236 | loff_t *pos) |
| 3237 | { |
| 3238 | unsigned long bucket = get_bucket(*pos); |
| 3239 | |
| 3240 | sk = sk_next(sk); |
| 3241 | if (sk) |
| 3242 | return sk; |
| 3243 | |
| 3244 | |
| 3245 | spin_unlock(&seq_file_net(seq)->unx.table.locks[bucket]); |
| 3246 | |
| 3247 | *pos = set_bucket_offset(++bucket, 1); |
| 3248 | |
| 3249 | return unix_get_first(seq, pos); |
| 3250 | } |
| 3251 | |
| 3252 | static void *unix_seq_start(struct seq_file *seq, loff_t *pos) |
| 3253 | { |
| 3254 | if (!*pos) |
| 3255 | return SEQ_START_TOKEN; |
| 3256 | |
| 3257 | return unix_get_first(seq, pos); |
| 3258 | } |
| 3259 | |
| 3260 | static void *unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) |
| 3261 | { |
| 3262 | ++*pos; |
| 3263 | |
| 3264 | if (v == SEQ_START_TOKEN) |
| 3265 | return unix_get_first(seq, pos); |
| 3266 | |
| 3267 | return unix_get_next(seq, v, pos); |
| 3268 | } |
| 3269 | |
| 3270 | static void unix_seq_stop(struct seq_file *seq, void *v) |
| 3271 | { |
| 3272 | struct sock *sk = v; |
| 3273 | |
| 3274 | if (sk) |
| 3275 | spin_unlock(&seq_file_net(seq)->unx.table.locks[sk->sk_hash]); |
| 3276 | } |
| 3277 | |
| 3278 | static int unix_seq_show(struct seq_file *seq, void *v) |
| 3279 | { |
| 3280 | |
| 3281 | if (v == SEQ_START_TOKEN) |
| 3282 | seq_puts(seq, "Num RefCount Protocol Flags Type St " |
| 3283 | "Inode Path\n"); |
| 3284 | else { |
| 3285 | struct sock *s = v; |
| 3286 | struct unix_sock *u = unix_sk(s); |
| 3287 | unix_state_lock(s); |
| 3288 | |
| 3289 | seq_printf(seq, "%pK: %08X %08X %08X %04X %02X %5lu", |
| 3290 | s, |
| 3291 | refcount_read(&s->sk_refcnt), |
| 3292 | 0, |
| 3293 | s->sk_state == TCP_LISTEN ? __SO_ACCEPTCON : 0, |
| 3294 | s->sk_type, |
| 3295 | s->sk_socket ? |
| 3296 | (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTED : SS_UNCONNECTED) : |
| 3297 | (s->sk_state == TCP_ESTABLISHED ? SS_CONNECTING : SS_DISCONNECTING), |
| 3298 | sock_i_ino(s)); |
| 3299 | |
| 3300 | if (u->addr) { // under a hash table lock here |
| 3301 | int i, len; |
| 3302 | seq_putc(seq, ' '); |
| 3303 | |
| 3304 | i = 0; |
| 3305 | len = u->addr->len - |
| 3306 | offsetof(struct sockaddr_un, sun_path); |
| 3307 | if (u->addr->name->sun_path[0]) { |
| 3308 | len--; |
| 3309 | } else { |
| 3310 | seq_putc(seq, '@'); |
| 3311 | i++; |
| 3312 | } |
| 3313 | for ( ; i < len; i++) |
| 3314 | seq_putc(seq, u->addr->name->sun_path[i] ?: |
| 3315 | '@'); |
| 3316 | } |
| 3317 | unix_state_unlock(s); |
| 3318 | seq_putc(seq, '\n'); |
| 3319 | } |
| 3320 | |
| 3321 | return 0; |
| 3322 | } |
| 3323 | |
| 3324 | static const struct seq_operations unix_seq_ops = { |
| 3325 | .start = unix_seq_start, |
| 3326 | .next = unix_seq_next, |
| 3327 | .stop = unix_seq_stop, |
| 3328 | .show = unix_seq_show, |
| 3329 | }; |
| 3330 | |
| 3331 | #ifdef CONFIG_BPF_SYSCALL |
| 3332 | struct bpf_unix_iter_state { |
| 3333 | struct seq_net_private p; |
| 3334 | unsigned int cur_sk; |
| 3335 | unsigned int end_sk; |
| 3336 | unsigned int max_sk; |
| 3337 | struct sock **batch; |
| 3338 | bool st_bucket_done; |
| 3339 | }; |
| 3340 | |
| 3341 | struct bpf_iter__unix { |
| 3342 | __bpf_md_ptr(struct bpf_iter_meta *, meta); |
| 3343 | __bpf_md_ptr(struct unix_sock *, unix_sk); |
| 3344 | uid_t uid __aligned(8); |
| 3345 | }; |
| 3346 | |
| 3347 | static int unix_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta, |
| 3348 | struct unix_sock *unix_sk, uid_t uid) |
| 3349 | { |
| 3350 | struct bpf_iter__unix ctx; |
| 3351 | |
| 3352 | meta->seq_num--; /* skip SEQ_START_TOKEN */ |
| 3353 | ctx.meta = meta; |
| 3354 | ctx.unix_sk = unix_sk; |
| 3355 | ctx.uid = uid; |
| 3356 | return bpf_iter_run_prog(prog, &ctx); |
| 3357 | } |
| 3358 | |
| 3359 | static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk) |
| 3360 | |
| 3361 | { |
| 3362 | struct bpf_unix_iter_state *iter = seq->private; |
| 3363 | unsigned int expected = 1; |
| 3364 | struct sock *sk; |
| 3365 | |
| 3366 | sock_hold(start_sk); |
| 3367 | iter->batch[iter->end_sk++] = start_sk; |
| 3368 | |
| 3369 | for (sk = sk_next(start_sk); sk; sk = sk_next(sk)) { |
| 3370 | if (iter->end_sk < iter->max_sk) { |
| 3371 | sock_hold(sk); |
| 3372 | iter->batch[iter->end_sk++] = sk; |
| 3373 | } |
| 3374 | |
| 3375 | expected++; |
| 3376 | } |
| 3377 | |
| 3378 | spin_unlock(&seq_file_net(seq)->unx.table.locks[start_sk->sk_hash]); |
| 3379 | |
| 3380 | return expected; |
| 3381 | } |
| 3382 | |
| 3383 | static void bpf_iter_unix_put_batch(struct bpf_unix_iter_state *iter) |
| 3384 | { |
| 3385 | while (iter->cur_sk < iter->end_sk) |
| 3386 | sock_put(iter->batch[iter->cur_sk++]); |
| 3387 | } |
| 3388 | |
| 3389 | static int bpf_iter_unix_realloc_batch(struct bpf_unix_iter_state *iter, |
| 3390 | unsigned int new_batch_sz) |
| 3391 | { |
| 3392 | struct sock **new_batch; |
| 3393 | |
| 3394 | new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz, |
| 3395 | GFP_USER | __GFP_NOWARN); |
| 3396 | if (!new_batch) |
| 3397 | return -ENOMEM; |
| 3398 | |
| 3399 | bpf_iter_unix_put_batch(iter); |
| 3400 | kvfree(iter->batch); |
| 3401 | iter->batch = new_batch; |
| 3402 | iter->max_sk = new_batch_sz; |
| 3403 | |
| 3404 | return 0; |
| 3405 | } |
| 3406 | |
| 3407 | static struct sock *bpf_iter_unix_batch(struct seq_file *seq, |
| 3408 | loff_t *pos) |
| 3409 | { |
| 3410 | struct bpf_unix_iter_state *iter = seq->private; |
| 3411 | unsigned int expected; |
| 3412 | bool resized = false; |
| 3413 | struct sock *sk; |
| 3414 | |
| 3415 | if (iter->st_bucket_done) |
| 3416 | *pos = set_bucket_offset(get_bucket(*pos) + 1, 1); |
| 3417 | |
| 3418 | again: |
| 3419 | /* Get a new batch */ |
| 3420 | iter->cur_sk = 0; |
| 3421 | iter->end_sk = 0; |
| 3422 | |
| 3423 | sk = unix_get_first(seq, pos); |
| 3424 | if (!sk) |
| 3425 | return NULL; /* Done */ |
| 3426 | |
| 3427 | expected = bpf_iter_unix_hold_batch(seq, sk); |
| 3428 | |
| 3429 | if (iter->end_sk == expected) { |
| 3430 | iter->st_bucket_done = true; |
| 3431 | return sk; |
| 3432 | } |
| 3433 | |
| 3434 | if (!resized && !bpf_iter_unix_realloc_batch(iter, expected * 3 / 2)) { |
| 3435 | resized = true; |
| 3436 | goto again; |
| 3437 | } |
| 3438 | |
| 3439 | return sk; |
| 3440 | } |
| 3441 | |
| 3442 | static void *bpf_iter_unix_seq_start(struct seq_file *seq, loff_t *pos) |
| 3443 | { |
| 3444 | if (!*pos) |
| 3445 | return SEQ_START_TOKEN; |
| 3446 | |
| 3447 | /* bpf iter does not support lseek, so it always |
| 3448 | * continue from where it was stop()-ped. |
| 3449 | */ |
| 3450 | return bpf_iter_unix_batch(seq, pos); |
| 3451 | } |
| 3452 | |
| 3453 | static void *bpf_iter_unix_seq_next(struct seq_file *seq, void *v, loff_t *pos) |
| 3454 | { |
| 3455 | struct bpf_unix_iter_state *iter = seq->private; |
| 3456 | struct sock *sk; |
| 3457 | |
| 3458 | /* Whenever seq_next() is called, the iter->cur_sk is |
| 3459 | * done with seq_show(), so advance to the next sk in |
| 3460 | * the batch. |
| 3461 | */ |
| 3462 | if (iter->cur_sk < iter->end_sk) |
| 3463 | sock_put(iter->batch[iter->cur_sk++]); |
| 3464 | |
| 3465 | ++*pos; |
| 3466 | |
| 3467 | if (iter->cur_sk < iter->end_sk) |
| 3468 | sk = iter->batch[iter->cur_sk]; |
| 3469 | else |
| 3470 | sk = bpf_iter_unix_batch(seq, pos); |
| 3471 | |
| 3472 | return sk; |
| 3473 | } |
| 3474 | |
| 3475 | static int bpf_iter_unix_seq_show(struct seq_file *seq, void *v) |
| 3476 | { |
| 3477 | struct bpf_iter_meta meta; |
| 3478 | struct bpf_prog *prog; |
| 3479 | struct sock *sk = v; |
| 3480 | uid_t uid; |
| 3481 | bool slow; |
| 3482 | int ret; |
| 3483 | |
| 3484 | if (v == SEQ_START_TOKEN) |
| 3485 | return 0; |
| 3486 | |
| 3487 | slow = lock_sock_fast(sk); |
| 3488 | |
| 3489 | if (unlikely(sk_unhashed(sk))) { |
| 3490 | ret = SEQ_SKIP; |
| 3491 | goto unlock; |
| 3492 | } |
| 3493 | |
| 3494 | uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)); |
| 3495 | meta.seq = seq; |
| 3496 | prog = bpf_iter_get_info(&meta, false); |
| 3497 | ret = unix_prog_seq_show(prog, &meta, v, uid); |
| 3498 | unlock: |
| 3499 | unlock_sock_fast(sk, slow); |
| 3500 | return ret; |
| 3501 | } |
| 3502 | |
| 3503 | static void bpf_iter_unix_seq_stop(struct seq_file *seq, void *v) |
| 3504 | { |
| 3505 | struct bpf_unix_iter_state *iter = seq->private; |
| 3506 | struct bpf_iter_meta meta; |
| 3507 | struct bpf_prog *prog; |
| 3508 | |
| 3509 | if (!v) { |
| 3510 | meta.seq = seq; |
| 3511 | prog = bpf_iter_get_info(&meta, true); |
| 3512 | if (prog) |
| 3513 | (void)unix_prog_seq_show(prog, &meta, v, 0); |
| 3514 | } |
| 3515 | |
| 3516 | if (iter->cur_sk < iter->end_sk) |
| 3517 | bpf_iter_unix_put_batch(iter); |
| 3518 | } |
| 3519 | |
| 3520 | static const struct seq_operations bpf_iter_unix_seq_ops = { |
| 3521 | .start = bpf_iter_unix_seq_start, |
| 3522 | .next = bpf_iter_unix_seq_next, |
| 3523 | .stop = bpf_iter_unix_seq_stop, |
| 3524 | .show = bpf_iter_unix_seq_show, |
| 3525 | }; |
| 3526 | #endif |
| 3527 | #endif |
| 3528 | |
| 3529 | static const struct net_proto_family unix_family_ops = { |
| 3530 | .family = PF_UNIX, |
| 3531 | .create = unix_create, |
| 3532 | .owner = THIS_MODULE, |
| 3533 | }; |
| 3534 | |
| 3535 | |
| 3536 | static int __net_init unix_net_init(struct net *net) |
| 3537 | { |
| 3538 | int i; |
| 3539 | |
| 3540 | net->unx.sysctl_max_dgram_qlen = 10; |
| 3541 | if (unix_sysctl_register(net)) |
| 3542 | goto out; |
| 3543 | |
| 3544 | #ifdef CONFIG_PROC_FS |
| 3545 | if (!proc_create_net("unix", 0, net->proc_net, &unix_seq_ops, |
| 3546 | sizeof(struct seq_net_private))) |
| 3547 | goto err_sysctl; |
| 3548 | #endif |
| 3549 | |
| 3550 | net->unx.table.locks = kvmalloc_array(UNIX_HASH_SIZE, |
| 3551 | sizeof(spinlock_t), GFP_KERNEL); |
| 3552 | if (!net->unx.table.locks) |
| 3553 | goto err_proc; |
| 3554 | |
| 3555 | net->unx.table.buckets = kvmalloc_array(UNIX_HASH_SIZE, |
| 3556 | sizeof(struct hlist_head), |
| 3557 | GFP_KERNEL); |
| 3558 | if (!net->unx.table.buckets) |
| 3559 | goto free_locks; |
| 3560 | |
| 3561 | for (i = 0; i < UNIX_HASH_SIZE; i++) { |
| 3562 | spin_lock_init(&net->unx.table.locks[i]); |
| 3563 | INIT_HLIST_HEAD(&net->unx.table.buckets[i]); |
| 3564 | } |
| 3565 | |
| 3566 | return 0; |
| 3567 | |
| 3568 | free_locks: |
| 3569 | kvfree(net->unx.table.locks); |
| 3570 | err_proc: |
| 3571 | #ifdef CONFIG_PROC_FS |
| 3572 | remove_proc_entry("unix", net->proc_net); |
| 3573 | err_sysctl: |
| 3574 | #endif |
| 3575 | unix_sysctl_unregister(net); |
| 3576 | out: |
| 3577 | return -ENOMEM; |
| 3578 | } |
| 3579 | |
| 3580 | static void __net_exit unix_net_exit(struct net *net) |
| 3581 | { |
| 3582 | kvfree(net->unx.table.buckets); |
| 3583 | kvfree(net->unx.table.locks); |
| 3584 | unix_sysctl_unregister(net); |
| 3585 | remove_proc_entry("unix", net->proc_net); |
| 3586 | } |
| 3587 | |
| 3588 | static struct pernet_operations unix_net_ops = { |
| 3589 | .init = unix_net_init, |
| 3590 | .exit = unix_net_exit, |
| 3591 | }; |
| 3592 | |
| 3593 | #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) |
| 3594 | DEFINE_BPF_ITER_FUNC(unix, struct bpf_iter_meta *meta, |
| 3595 | struct unix_sock *unix_sk, uid_t uid) |
| 3596 | |
| 3597 | #define INIT_BATCH_SZ 16 |
| 3598 | |
| 3599 | static int bpf_iter_init_unix(void *priv_data, struct bpf_iter_aux_info *aux) |
| 3600 | { |
| 3601 | struct bpf_unix_iter_state *iter = priv_data; |
| 3602 | int err; |
| 3603 | |
| 3604 | err = bpf_iter_init_seq_net(priv_data, aux); |
| 3605 | if (err) |
| 3606 | return err; |
| 3607 | |
| 3608 | err = bpf_iter_unix_realloc_batch(iter, INIT_BATCH_SZ); |
| 3609 | if (err) { |
| 3610 | bpf_iter_fini_seq_net(priv_data); |
| 3611 | return err; |
| 3612 | } |
| 3613 | |
| 3614 | return 0; |
| 3615 | } |
| 3616 | |
| 3617 | static void bpf_iter_fini_unix(void *priv_data) |
| 3618 | { |
| 3619 | struct bpf_unix_iter_state *iter = priv_data; |
| 3620 | |
| 3621 | bpf_iter_fini_seq_net(priv_data); |
| 3622 | kvfree(iter->batch); |
| 3623 | } |
| 3624 | |
| 3625 | static const struct bpf_iter_seq_info unix_seq_info = { |
| 3626 | .seq_ops = &bpf_iter_unix_seq_ops, |
| 3627 | .init_seq_private = bpf_iter_init_unix, |
| 3628 | .fini_seq_private = bpf_iter_fini_unix, |
| 3629 | .seq_priv_size = sizeof(struct bpf_unix_iter_state), |
| 3630 | }; |
| 3631 | |
| 3632 | static const struct bpf_func_proto * |
| 3633 | bpf_iter_unix_get_func_proto(enum bpf_func_id func_id, |
| 3634 | const struct bpf_prog *prog) |
| 3635 | { |
| 3636 | switch (func_id) { |
| 3637 | case BPF_FUNC_setsockopt: |
| 3638 | return &bpf_sk_setsockopt_proto; |
| 3639 | case BPF_FUNC_getsockopt: |
| 3640 | return &bpf_sk_getsockopt_proto; |
| 3641 | default: |
| 3642 | return NULL; |
| 3643 | } |
| 3644 | } |
| 3645 | |
| 3646 | static struct bpf_iter_reg unix_reg_info = { |
| 3647 | .target = "unix", |
| 3648 | .ctx_arg_info_size = 1, |
| 3649 | .ctx_arg_info = { |
| 3650 | { offsetof(struct bpf_iter__unix, unix_sk), |
| 3651 | PTR_TO_BTF_ID_OR_NULL }, |
| 3652 | }, |
| 3653 | .get_func_proto = bpf_iter_unix_get_func_proto, |
| 3654 | .seq_info = &unix_seq_info, |
| 3655 | }; |
| 3656 | |
| 3657 | static void __init bpf_iter_register(void) |
| 3658 | { |
| 3659 | unix_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_UNIX]; |
| 3660 | if (bpf_iter_reg_target(&unix_reg_info)) |
| 3661 | pr_warn("Warning: could not register bpf iterator unix\n"); |
| 3662 | } |
| 3663 | #endif |
| 3664 | |
| 3665 | static int __init af_unix_init(void) |
| 3666 | { |
| 3667 | int i, rc = -1; |
| 3668 | |
| 3669 | BUILD_BUG_ON(sizeof(struct unix_skb_parms) > sizeof_field(struct sk_buff, cb)); |
| 3670 | |
| 3671 | for (i = 0; i < UNIX_HASH_SIZE / 2; i++) { |
| 3672 | spin_lock_init(&bsd_socket_locks[i]); |
| 3673 | INIT_HLIST_HEAD(&bsd_socket_buckets[i]); |
| 3674 | } |
| 3675 | |
| 3676 | rc = proto_register(&unix_dgram_proto, 1); |
| 3677 | if (rc != 0) { |
| 3678 | pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__); |
| 3679 | goto out; |
| 3680 | } |
| 3681 | |
| 3682 | rc = proto_register(&unix_stream_proto, 1); |
| 3683 | if (rc != 0) { |
| 3684 | pr_crit("%s: Cannot create unix_sock SLAB cache!\n", __func__); |
| 3685 | proto_unregister(&unix_dgram_proto); |
| 3686 | goto out; |
| 3687 | } |
| 3688 | |
| 3689 | sock_register(&unix_family_ops); |
| 3690 | register_pernet_subsys(&unix_net_ops); |
| 3691 | unix_bpf_build_proto(); |
| 3692 | |
| 3693 | #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) |
| 3694 | bpf_iter_register(); |
| 3695 | #endif |
| 3696 | |
| 3697 | out: |
| 3698 | return rc; |
| 3699 | } |
| 3700 | |
| 3701 | /* Later than subsys_initcall() because we depend on stuff initialised there */ |
| 3702 | fs_initcall(af_unix_init); |