1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1991, 1993 3 * The Regents of the University of California. 4 * Copyright 2004-2006 Robert N. M. Watson 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 4. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * From: @(#)uipc_usrreq.c 8.3 (Berkeley) 1/4/94 32 */ 33 34 /* 35 * UNIX Domain (Local) Sockets 36 * 37 * This is an implementation of UNIX (local) domain sockets. Each socket has 38 * an associated struct unpcb (UNIX protocol control block). Stream sockets 39 * may be connected to 0 or 1 other socket. Datagram sockets may be 40 * connected to 0, 1, or many other sockets. Sockets may be created and 41 * connected in pairs (socketpair(2)), or bound/connected to using the file 42 * system name space. For most purposes, only the receive socket buffer is 43 * used, as sending on one socket delivers directly to the receive socket 44 * buffer of a second socket. The implementation is substantially 45 * complicated by the fact that "ancillary data", such as file descriptors or 46 * credentials, may be passed across UNIX domain sockets. The potential for 47 * passing UNIX domain sockets over other UNIX domain sockets requires the 48 * implementation of a simple garbage collector to find and tear down cycles 49 * of disconnected sockets. 50 */ 51 52 #include <sys/cdefs.h> 53 __FBSDID("$FreeBSD$"); 54 55 #include "opt_mac.h" 56 57 #include <sys/param.h> 58 #include <sys/domain.h> 59 #include <sys/fcntl.h> 60 #include <sys/malloc.h> /* XXX must be before <sys/file.h> */ 61 #include <sys/eventhandler.h> 62 #include <sys/file.h> 63 #include <sys/filedesc.h> 64 #include <sys/jail.h> 65 #include <sys/kernel.h> 66 #include <sys/lock.h> 67 #include <sys/mac.h> 68 #include <sys/mbuf.h> 69 #include <sys/mount.h> 70 #include <sys/mutex.h> 71 #include <sys/namei.h> 72 #include <sys/proc.h> 73 #include <sys/protosw.h> 74 #include <sys/resourcevar.h> 75 #include <sys/socket.h> 76 #include <sys/socketvar.h> 77 #include <sys/signalvar.h> 78 #include <sys/stat.h> 79 #include <sys/sx.h> 80 #include <sys/sysctl.h> 81 #include <sys/systm.h> 82 #include <sys/taskqueue.h> 83 #include <sys/un.h> 84 #include <sys/unpcb.h> 85 #include <sys/vnode.h> 86 87 #include <vm/uma.h> 88 89 static uma_zone_t unp_zone; 90 static unp_gen_t unp_gencnt; 91 static u_int unp_count; 92 93 static struct unp_head unp_shead, unp_dhead; 94 95 /* 96 * Unix communications domain. 97 * 98 * TODO: 99 * SEQPACKET, RDM 100 * rethink name space problems 101 * need a proper out-of-band 102 * lock pushdown 103 */ 104 static const struct sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL }; 105 static ino_t unp_ino; /* prototype for fake inode numbers */ 106 struct mbuf *unp_addsockcred(struct thread *, struct mbuf *); 107 108 /* 109 * Both send and receive buffers are allocated PIPSIZ bytes of buffering for 110 * stream sockets, although the total for sender and receiver is actually 111 * only PIPSIZ. 112 * 113 * Datagram sockets really use the sendspace as the maximum datagram size, 114 * and don't really want to reserve the sendspace. Their recvspace should be 115 * large enough for at least one max-size datagram plus address. 116 */ 117 #ifndef PIPSIZ 118 #define PIPSIZ 8192 119 #endif 120 static u_long unpst_sendspace = PIPSIZ; 121 static u_long unpst_recvspace = PIPSIZ; 122 static u_long unpdg_sendspace = 2*1024; /* really max datagram size */ 123 static u_long unpdg_recvspace = 4*1024; 124 125 static int unp_rights; /* file descriptors in flight */ 126 127 SYSCTL_DECL(_net_local_stream); 128 SYSCTL_ULONG(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW, 129 &unpst_sendspace, 0, ""); 130 SYSCTL_ULONG(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW, 131 &unpst_recvspace, 0, ""); 132 SYSCTL_DECL(_net_local_dgram); 133 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW, 134 &unpdg_sendspace, 0, ""); 135 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW, 136 &unpdg_recvspace, 0, ""); 137 SYSCTL_DECL(_net_local); 138 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0, ""); 139 140 /* 141 * Currently, UNIX domain sockets are protected by a single subsystem lock, 142 * which covers global data structures and variables, the contents of each 143 * per-socket unpcb structure, and the so_pcb field in sockets attached to 144 * the UNIX domain. This provides for a moderate degree of paralellism, as 145 * receive operations on UNIX domain sockets do not need to acquire the 146 * subsystem lock. Finer grained locking to permit send() without acquiring 147 * a global lock would be a logical next step. 148 * 149 * The UNIX domain socket lock preceds all socket layer locks, including the 150 * socket lock and socket buffer lock, permitting UNIX domain socket code to 151 * call into socket support routines without releasing its locks. 152 * 153 * Some caution is required in areas where the UNIX domain socket code enters 154 * VFS in order to create or find rendezvous points. This results in 155 * dropping of the UNIX domain socket subsystem lock, acquisition of the 156 * Giant lock, and potential sleeping. This increases the chances of races, 157 * and exposes weaknesses in the socket->protocol API by offering poor 158 * failure modes. 159 */ 160 static struct mtx unp_mtx; 161 #define UNP_LOCK_INIT() \ 162 mtx_init(&unp_mtx, "unp", NULL, MTX_DEF) 163 #define UNP_LOCK() mtx_lock(&unp_mtx) 164 #define UNP_UNLOCK() mtx_unlock(&unp_mtx) 165 #define UNP_LOCK_ASSERT() mtx_assert(&unp_mtx, MA_OWNED) 166 #define UNP_UNLOCK_ASSERT() mtx_assert(&unp_mtx, MA_NOTOWNED) 167 168 /* 169 * Garbage collection of cyclic file descriptor/socket references occurs 170 * asynchronously in a taskqueue context in order to avoid recursion and 171 * reentrance in the UNIX domain socket, file descriptor, and socket layer 172 * code. See unp_gc() for a full description. 173 */ 174 static struct task unp_gc_task; 175 176 static int unp_connect(struct socket *,struct sockaddr *, struct thread *); 177 static int unp_connect2(struct socket *so, struct socket *so2, int); 178 static void unp_disconnect(struct unpcb *); 179 static void unp_shutdown(struct unpcb *); 180 static void unp_drop(struct unpcb *, int); 181 static void unp_gc(__unused void *, int); 182 static void unp_scan(struct mbuf *, void (*)(struct file *)); 183 static void unp_mark(struct file *); 184 static void unp_discard(struct file *); 185 static void unp_freerights(struct file **, int); 186 static int unp_internalize(struct mbuf **, struct thread *); 187 static int unp_listen(struct socket *, struct unpcb *, int, 188 struct thread *); 189 190 static void 191 uipc_abort(struct socket *so) 192 { 193 struct unpcb *unp; 194 195 unp = sotounpcb(so); 196 KASSERT(unp != NULL, ("uipc_abort: unp == NULL")); 197 UNP_LOCK(); 198 unp_drop(unp, ECONNABORTED); 199 UNP_UNLOCK(); 200 } 201 202 static int 203 uipc_accept(struct socket *so, struct sockaddr **nam) 204 { 205 struct unpcb *unp; 206 const struct sockaddr *sa; 207 208 /* 209 * Pass back name of connected socket, if it was bound and we are 210 * still connected (our peer may have closed already!). 211 */ 212 unp = sotounpcb(so); 213 KASSERT(unp != NULL, ("uipc_accept: unp == NULL")); 214 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 215 UNP_LOCK(); 216 if (unp->unp_conn != NULL && unp->unp_conn->unp_addr != NULL) 217 sa = (struct sockaddr *) unp->unp_conn->unp_addr; 218 else 219 sa = &sun_noname; 220 bcopy(sa, *nam, sa->sa_len); 221 UNP_UNLOCK(); 222 return (0); 223 } 224 225 static int 226 uipc_attach(struct socket *so, int proto, struct thread *td) 227 { 228 struct unpcb *unp; 229 int error; 230 231 KASSERT(so->so_pcb == NULL, ("uipc_attach: so_pcb != NULL")); 232 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 233 switch (so->so_type) { 234 235 case SOCK_STREAM: 236 error = soreserve(so, unpst_sendspace, unpst_recvspace); 237 break; 238 239 case SOCK_DGRAM: 240 error = soreserve(so, unpdg_sendspace, unpdg_recvspace); 241 break; 242 243 default: 244 panic("unp_attach"); 245 } 246 if (error) 247 return (error); 248 } 249 unp = uma_zalloc(unp_zone, M_WAITOK | M_ZERO); 250 if (unp == NULL) 251 return (ENOBUFS); 252 LIST_INIT(&unp->unp_refs); 253 unp->unp_socket = so; 254 so->so_pcb = unp; 255 256 UNP_LOCK(); 257 unp->unp_gencnt = ++unp_gencnt; 258 unp_count++; 259 LIST_INSERT_HEAD(so->so_type == SOCK_DGRAM ? &unp_dhead 260 : &unp_shead, unp, unp_link); 261 UNP_UNLOCK(); 262 263 return (0); 264 } 265 266 static int 267 uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td) 268 { 269 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 270 struct vattr vattr; 271 int error, namelen; 272 struct nameidata nd; 273 struct unpcb *unp; 274 struct vnode *vp; 275 struct mount *mp; 276 char *buf; 277 278 unp = sotounpcb(so); 279 KASSERT(unp != NULL, ("uipc_bind: unp == NULL")); 280 281 namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path); 282 if (namelen <= 0) 283 return (EINVAL); 284 285 /* 286 * We don't allow simultaneous bind() calls on a single UNIX domain 287 * socket, so flag in-progress operations, and return an error if an 288 * operation is already in progress. 289 * 290 * Historically, we have not allowed a socket to be rebound, so this 291 * also returns an error. Not allowing re-binding certainly 292 * simplifies the implementation and avoids a great many possible 293 * failure modes. 294 */ 295 UNP_LOCK(); 296 if (unp->unp_vnode != NULL) { 297 UNP_UNLOCK(); 298 return (EINVAL); 299 } 300 if (unp->unp_flags & UNP_BINDING) { 301 UNP_UNLOCK(); 302 return (EALREADY); 303 } 304 unp->unp_flags |= UNP_BINDING; 305 UNP_UNLOCK(); 306 307 buf = malloc(namelen + 1, M_TEMP, M_WAITOK); 308 strlcpy(buf, soun->sun_path, namelen + 1); 309 310 mtx_lock(&Giant); 311 restart: 312 mtx_assert(&Giant, MA_OWNED); 313 NDINIT(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME, UIO_SYSSPACE, 314 buf, td); 315 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 316 error = namei(&nd); 317 if (error) 318 goto error; 319 vp = nd.ni_vp; 320 if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) { 321 NDFREE(&nd, NDF_ONLY_PNBUF); 322 if (nd.ni_dvp == vp) 323 vrele(nd.ni_dvp); 324 else 325 vput(nd.ni_dvp); 326 if (vp != NULL) { 327 vrele(vp); 328 error = EADDRINUSE; 329 goto error; 330 } 331 error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH); 332 if (error) 333 goto error; 334 goto restart; 335 } 336 VATTR_NULL(&vattr); 337 vattr.va_type = VSOCK; 338 vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask); 339 #ifdef MAC 340 error = mac_check_vnode_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd, 341 &vattr); 342 #endif 343 if (error == 0) { 344 VOP_LEASE(nd.ni_dvp, td, td->td_ucred, LEASE_WRITE); 345 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 346 } 347 NDFREE(&nd, NDF_ONLY_PNBUF); 348 vput(nd.ni_dvp); 349 if (error) { 350 vn_finished_write(mp); 351 goto error; 352 } 353 vp = nd.ni_vp; 354 ASSERT_VOP_LOCKED(vp, "uipc_bind"); 355 soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK); 356 UNP_LOCK(); 357 vp->v_socket = unp->unp_socket; 358 unp->unp_vnode = vp; 359 unp->unp_addr = soun; 360 unp->unp_flags &= ~UNP_BINDING; 361 UNP_UNLOCK(); 362 VOP_UNLOCK(vp, 0, td); 363 vn_finished_write(mp); 364 mtx_unlock(&Giant); 365 free(buf, M_TEMP); 366 return (0); 367 error: 368 UNP_LOCK(); 369 unp->unp_flags &= ~UNP_BINDING; 370 UNP_UNLOCK(); 371 mtx_unlock(&Giant); 372 free(buf, M_TEMP); 373 return (error); 374 } 375 376 static int 377 uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 378 { 379 int error; 380 381 KASSERT(td == curthread, ("uipc_connect: td != curthread")); 382 UNP_LOCK(); 383 error = unp_connect(so, nam, td); 384 UNP_UNLOCK(); 385 return (error); 386 } 387 388 /* 389 * XXXRW: Should also unbind? 390 */ 391 static void 392 uipc_close(struct socket *so) 393 { 394 struct unpcb *unp; 395 396 unp = sotounpcb(so); 397 KASSERT(unp != NULL, ("uipc_close: unp == NULL")); 398 UNP_LOCK(); 399 unp_disconnect(unp); 400 UNP_UNLOCK(); 401 } 402 403 int 404 uipc_connect2(struct socket *so1, struct socket *so2) 405 { 406 struct unpcb *unp; 407 int error; 408 409 unp = sotounpcb(so1); 410 KASSERT(unp != NULL, ("uipc_connect2: unp == NULL")); 411 UNP_LOCK(); 412 error = unp_connect2(so1, so2, PRU_CONNECT2); 413 UNP_UNLOCK(); 414 return (error); 415 } 416 417 /* control is EOPNOTSUPP */ 418 419 static void 420 uipc_detach(struct socket *so) 421 { 422 int local_unp_rights; 423 struct unpcb *unp; 424 struct vnode *vp; 425 426 unp = sotounpcb(so); 427 KASSERT(unp != NULL, ("uipc_detach: unp == NULL")); 428 UNP_LOCK(); 429 LIST_REMOVE(unp, unp_link); 430 unp->unp_gencnt = ++unp_gencnt; 431 --unp_count; 432 if ((vp = unp->unp_vnode) != NULL) { 433 /* 434 * XXXRW: should v_socket be frobbed only while holding 435 * Giant? 436 */ 437 unp->unp_vnode->v_socket = NULL; 438 unp->unp_vnode = NULL; 439 } 440 if (unp->unp_conn != NULL) 441 unp_disconnect(unp); 442 while (!LIST_EMPTY(&unp->unp_refs)) { 443 struct unpcb *ref = LIST_FIRST(&unp->unp_refs); 444 unp_drop(ref, ECONNRESET); 445 } 446 unp->unp_socket->so_pcb = NULL; 447 local_unp_rights = unp_rights; 448 UNP_UNLOCK(); 449 if (unp->unp_addr != NULL) 450 FREE(unp->unp_addr, M_SONAME); 451 uma_zfree(unp_zone, unp); 452 if (vp) { 453 int vfslocked; 454 455 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 456 vrele(vp); 457 VFS_UNLOCK_GIANT(vfslocked); 458 } 459 if (local_unp_rights) 460 taskqueue_enqueue(taskqueue_thread, &unp_gc_task); 461 } 462 463 static int 464 uipc_disconnect(struct socket *so) 465 { 466 struct unpcb *unp; 467 468 unp = sotounpcb(so); 469 KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL")); 470 UNP_LOCK(); 471 unp_disconnect(unp); 472 UNP_UNLOCK(); 473 return (0); 474 } 475 476 static int 477 uipc_listen(struct socket *so, int backlog, struct thread *td) 478 { 479 struct unpcb *unp; 480 int error; 481 482 unp = sotounpcb(so); 483 KASSERT(unp != NULL, ("uipc_listen: unp == NULL")); 484 UNP_LOCK(); 485 if (unp->unp_vnode == NULL) { 486 UNP_UNLOCK(); 487 return (EINVAL); 488 } 489 error = unp_listen(so, unp, backlog, td); 490 UNP_UNLOCK(); 491 return (error); 492 } 493 494 static int 495 uipc_peeraddr(struct socket *so, struct sockaddr **nam) 496 { 497 struct unpcb *unp; 498 const struct sockaddr *sa; 499 500 unp = sotounpcb(so); 501 KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL")); 502 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 503 UNP_LOCK(); 504 if (unp->unp_conn != NULL && unp->unp_conn->unp_addr!= NULL) 505 sa = (struct sockaddr *) unp->unp_conn->unp_addr; 506 else { 507 /* 508 * XXX: It seems that this test always fails even when 509 * connection is established. So, this else clause is 510 * added as workaround to return PF_LOCAL sockaddr. 511 */ 512 sa = &sun_noname; 513 } 514 bcopy(sa, *nam, sa->sa_len); 515 UNP_UNLOCK(); 516 return (0); 517 } 518 519 static int 520 uipc_rcvd(struct socket *so, int flags) 521 { 522 struct unpcb *unp; 523 struct socket *so2; 524 u_int mbcnt, sbcc; 525 u_long newhiwat; 526 527 unp = sotounpcb(so); 528 KASSERT(unp != NULL, ("uipc_rcvd: unp == NULL")); 529 switch (so->so_type) { 530 case SOCK_DGRAM: 531 panic("uipc_rcvd DGRAM?"); 532 /*NOTREACHED*/ 533 534 case SOCK_STREAM: 535 /* 536 * Adjust backpressure on sender and wakeup any waiting to 537 * write. 538 */ 539 SOCKBUF_LOCK(&so->so_rcv); 540 mbcnt = so->so_rcv.sb_mbcnt; 541 sbcc = so->so_rcv.sb_cc; 542 SOCKBUF_UNLOCK(&so->so_rcv); 543 UNP_LOCK(); 544 if (unp->unp_conn == NULL) { 545 UNP_UNLOCK(); 546 break; 547 } 548 so2 = unp->unp_conn->unp_socket; 549 SOCKBUF_LOCK(&so2->so_snd); 550 so2->so_snd.sb_mbmax += unp->unp_mbcnt - mbcnt; 551 newhiwat = so2->so_snd.sb_hiwat + unp->unp_cc - sbcc; 552 (void)chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.sb_hiwat, 553 newhiwat, RLIM_INFINITY); 554 sowwakeup_locked(so2); 555 unp->unp_mbcnt = mbcnt; 556 unp->unp_cc = sbcc; 557 UNP_UNLOCK(); 558 break; 559 560 default: 561 panic("uipc_rcvd unknown socktype"); 562 } 563 return (0); 564 } 565 566 /* pru_rcvoob is EOPNOTSUPP */ 567 568 static int 569 uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, 570 struct mbuf *control, struct thread *td) 571 { 572 struct unpcb *unp, *unp2; 573 struct socket *so2; 574 u_int mbcnt, sbcc; 575 u_long newhiwat; 576 int error = 0; 577 578 unp = sotounpcb(so); 579 KASSERT(unp != NULL, ("uipc_send: unp == NULL")); 580 if (flags & PRUS_OOB) { 581 error = EOPNOTSUPP; 582 goto release; 583 } 584 585 if (control != NULL && (error = unp_internalize(&control, td))) 586 goto release; 587 588 UNP_LOCK(); 589 switch (so->so_type) { 590 case SOCK_DGRAM: 591 { 592 const struct sockaddr *from; 593 594 if (nam != NULL) { 595 if (unp->unp_conn != NULL) { 596 error = EISCONN; 597 break; 598 } 599 error = unp_connect(so, nam, td); 600 if (error) 601 break; 602 } else { 603 if (unp->unp_conn == NULL) { 604 error = ENOTCONN; 605 break; 606 } 607 } 608 unp2 = unp->unp_conn; 609 so2 = unp2->unp_socket; 610 if (unp->unp_addr != NULL) 611 from = (struct sockaddr *)unp->unp_addr; 612 else 613 from = &sun_noname; 614 if (unp2->unp_flags & UNP_WANTCRED) 615 control = unp_addsockcred(td, control); 616 SOCKBUF_LOCK(&so2->so_rcv); 617 if (sbappendaddr_locked(&so2->so_rcv, from, m, control)) { 618 sorwakeup_locked(so2); 619 m = NULL; 620 control = NULL; 621 } else { 622 SOCKBUF_UNLOCK(&so2->so_rcv); 623 error = ENOBUFS; 624 } 625 if (nam != NULL) 626 unp_disconnect(unp); 627 break; 628 } 629 630 case SOCK_STREAM: 631 /* 632 * Connect if not connected yet. 633 * 634 * Note: A better implementation would complain if not equal 635 * to the peer's address. 636 */ 637 if ((so->so_state & SS_ISCONNECTED) == 0) { 638 if (nam != NULL) { 639 error = unp_connect(so, nam, td); 640 if (error) 641 break; /* XXX */ 642 } else { 643 error = ENOTCONN; 644 break; 645 } 646 } 647 648 /* Lockless read. */ 649 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 650 error = EPIPE; 651 break; 652 } 653 unp2 = unp->unp_conn; 654 if (unp2 == NULL) 655 panic("uipc_send connected but no connection?"); 656 so2 = unp2->unp_socket; 657 SOCKBUF_LOCK(&so2->so_rcv); 658 if (unp2->unp_flags & UNP_WANTCRED) { 659 /* 660 * Credentials are passed only once on 661 * SOCK_STREAM. 662 */ 663 unp2->unp_flags &= ~UNP_WANTCRED; 664 control = unp_addsockcred(td, control); 665 } 666 /* 667 * Send to paired receive port, and then reduce send buffer 668 * hiwater marks to maintain backpressure. Wake up readers. 669 */ 670 if (control != NULL) { 671 if (sbappendcontrol_locked(&so2->so_rcv, m, control)) 672 control = NULL; 673 } else { 674 sbappend_locked(&so2->so_rcv, m); 675 } 676 mbcnt = so2->so_rcv.sb_mbcnt - unp2->unp_mbcnt; 677 unp2->unp_mbcnt = so2->so_rcv.sb_mbcnt; 678 sbcc = so2->so_rcv.sb_cc; 679 sorwakeup_locked(so2); 680 681 SOCKBUF_LOCK(&so->so_snd); 682 newhiwat = so->so_snd.sb_hiwat - (sbcc - unp2->unp_cc); 683 (void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat, 684 newhiwat, RLIM_INFINITY); 685 so->so_snd.sb_mbmax -= mbcnt; 686 SOCKBUF_UNLOCK(&so->so_snd); 687 688 unp2->unp_cc = sbcc; 689 m = NULL; 690 break; 691 692 default: 693 panic("uipc_send unknown socktype"); 694 } 695 696 /* 697 * SEND_EOF is equivalent to a SEND followed by 698 * a SHUTDOWN. 699 */ 700 if (flags & PRUS_EOF) { 701 socantsendmore(so); 702 unp_shutdown(unp); 703 } 704 UNP_UNLOCK(); 705 706 if (control != NULL && error != 0) 707 unp_dispose(control); 708 709 release: 710 if (control != NULL) 711 m_freem(control); 712 if (m != NULL) 713 m_freem(m); 714 return (error); 715 } 716 717 static int 718 uipc_sense(struct socket *so, struct stat *sb) 719 { 720 struct unpcb *unp; 721 struct socket *so2; 722 723 unp = sotounpcb(so); 724 KASSERT(unp != NULL, ("uipc_sense: unp == NULL")); 725 UNP_LOCK(); 726 sb->st_blksize = so->so_snd.sb_hiwat; 727 if (so->so_type == SOCK_STREAM && unp->unp_conn != NULL) { 728 so2 = unp->unp_conn->unp_socket; 729 sb->st_blksize += so2->so_rcv.sb_cc; 730 } 731 sb->st_dev = NODEV; 732 if (unp->unp_ino == 0) 733 unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino; 734 sb->st_ino = unp->unp_ino; 735 UNP_UNLOCK(); 736 return (0); 737 } 738 739 static int 740 uipc_shutdown(struct socket *so) 741 { 742 struct unpcb *unp; 743 744 unp = sotounpcb(so); 745 KASSERT(unp != NULL, ("uipc_shutdown: unp == NULL")); 746 UNP_LOCK(); 747 socantsendmore(so); 748 unp_shutdown(unp); 749 UNP_UNLOCK(); 750 return (0); 751 } 752 753 static int 754 uipc_sockaddr(struct socket *so, struct sockaddr **nam) 755 { 756 struct unpcb *unp; 757 const struct sockaddr *sa; 758 759 unp = sotounpcb(so); 760 KASSERT(unp != NULL, ("uipc_sockaddr: unp == NULL")); 761 *nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 762 UNP_LOCK(); 763 if (unp->unp_addr != NULL) 764 sa = (struct sockaddr *) unp->unp_addr; 765 else 766 sa = &sun_noname; 767 bcopy(sa, *nam, sa->sa_len); 768 UNP_UNLOCK(); 769 return (0); 770 } 771 772 struct pr_usrreqs uipc_usrreqs = { 773 .pru_abort = uipc_abort, 774 .pru_accept = uipc_accept, 775 .pru_attach = uipc_attach, 776 .pru_bind = uipc_bind, 777 .pru_connect = uipc_connect, 778 .pru_connect2 = uipc_connect2, 779 .pru_detach = uipc_detach, 780 .pru_disconnect = uipc_disconnect, 781 .pru_listen = uipc_listen, 782 .pru_peeraddr = uipc_peeraddr, 783 .pru_rcvd = uipc_rcvd, 784 .pru_send = uipc_send, 785 .pru_sense = uipc_sense, 786 .pru_shutdown = uipc_shutdown, 787 .pru_sockaddr = uipc_sockaddr, 788 .pru_sosend = sosend_generic, 789 .pru_soreceive = soreceive_generic, 790 .pru_sopoll = sopoll_generic, 791 .pru_close = uipc_close, 792 }; 793 794 int 795 uipc_ctloutput(struct socket *so, struct sockopt *sopt) 796 { 797 struct unpcb *unp; 798 struct xucred xu; 799 int error, optval; 800 801 if (sopt->sopt_level != 0) 802 return (EINVAL); 803 804 unp = sotounpcb(so); 805 KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL")); 806 UNP_LOCK(); 807 error = 0; 808 switch (sopt->sopt_dir) { 809 case SOPT_GET: 810 switch (sopt->sopt_name) { 811 case LOCAL_PEERCRED: 812 if (unp->unp_flags & UNP_HAVEPC) 813 xu = unp->unp_peercred; 814 else { 815 if (so->so_type == SOCK_STREAM) 816 error = ENOTCONN; 817 else 818 error = EINVAL; 819 } 820 if (error == 0) 821 error = sooptcopyout(sopt, &xu, sizeof(xu)); 822 break; 823 case LOCAL_CREDS: 824 optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0; 825 error = sooptcopyout(sopt, &optval, sizeof(optval)); 826 break; 827 case LOCAL_CONNWAIT: 828 optval = unp->unp_flags & UNP_CONNWAIT ? 1 : 0; 829 error = sooptcopyout(sopt, &optval, sizeof(optval)); 830 break; 831 default: 832 error = EOPNOTSUPP; 833 break; 834 } 835 break; 836 case SOPT_SET: 837 switch (sopt->sopt_name) { 838 case LOCAL_CREDS: 839 case LOCAL_CONNWAIT: 840 error = sooptcopyin(sopt, &optval, sizeof(optval), 841 sizeof(optval)); 842 if (error) 843 break; 844 845 #define OPTSET(bit) \ 846 if (optval) \ 847 unp->unp_flags |= bit; \ 848 else \ 849 unp->unp_flags &= ~bit; 850 851 switch (sopt->sopt_name) { 852 case LOCAL_CREDS: 853 OPTSET(UNP_WANTCRED); 854 break; 855 case LOCAL_CONNWAIT: 856 OPTSET(UNP_CONNWAIT); 857 break; 858 default: 859 break; 860 } 861 break; 862 #undef OPTSET 863 default: 864 error = ENOPROTOOPT; 865 break; 866 } 867 break; 868 default: 869 error = EOPNOTSUPP; 870 break; 871 } 872 UNP_UNLOCK(); 873 return (error); 874 } 875 876 static int 877 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td) 878 { 879 struct sockaddr_un *soun = (struct sockaddr_un *)nam; 880 struct vnode *vp; 881 struct socket *so2, *so3; 882 struct unpcb *unp, *unp2, *unp3; 883 int error, len; 884 struct nameidata nd; 885 char buf[SOCK_MAXADDRLEN]; 886 struct sockaddr *sa; 887 888 UNP_LOCK_ASSERT(); 889 890 unp = sotounpcb(so); 891 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 892 len = nam->sa_len - offsetof(struct sockaddr_un, sun_path); 893 if (len <= 0) 894 return (EINVAL); 895 strlcpy(buf, soun->sun_path, len + 1); 896 if (unp->unp_flags & UNP_CONNECTING) { 897 UNP_UNLOCK(); 898 return (EALREADY); 899 } 900 UNP_UNLOCK(); 901 sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK); 902 mtx_lock(&Giant); 903 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, buf, td); 904 error = namei(&nd); 905 if (error) 906 vp = NULL; 907 else 908 vp = nd.ni_vp; 909 ASSERT_VOP_LOCKED(vp, "unp_connect"); 910 NDFREE(&nd, NDF_ONLY_PNBUF); 911 if (error) 912 goto bad; 913 914 if (vp->v_type != VSOCK) { 915 error = ENOTSOCK; 916 goto bad; 917 } 918 error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td); 919 if (error) 920 goto bad; 921 mtx_unlock(&Giant); 922 UNP_LOCK(); 923 unp = sotounpcb(so); 924 KASSERT(unp != NULL, ("unp_connect: unp == NULL")); 925 so2 = vp->v_socket; 926 if (so2 == NULL) { 927 error = ECONNREFUSED; 928 goto bad2; 929 } 930 if (so->so_type != so2->so_type) { 931 error = EPROTOTYPE; 932 goto bad2; 933 } 934 if (so->so_proto->pr_flags & PR_CONNREQUIRED) { 935 if (so2->so_options & SO_ACCEPTCONN) { 936 /* 937 * NB: drop locks here so unp_attach is entered w/o 938 * locks; this avoids a recursive lock of the head 939 * and holding sleep locks across a (potentially) 940 * blocking malloc. 941 */ 942 UNP_UNLOCK(); 943 so3 = sonewconn(so2, 0); 944 UNP_LOCK(); 945 } else 946 so3 = NULL; 947 if (so3 == NULL) { 948 error = ECONNREFUSED; 949 goto bad2; 950 } 951 unp = sotounpcb(so); 952 unp2 = sotounpcb(so2); 953 unp3 = sotounpcb(so3); 954 if (unp2->unp_addr != NULL) { 955 bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len); 956 unp3->unp_addr = (struct sockaddr_un *) sa; 957 sa = NULL; 958 } 959 /* 960 * unp_peercred management: 961 * 962 * The connecter's (client's) credentials are copied from its 963 * process structure at the time of connect() (which is now). 964 */ 965 cru2x(td->td_ucred, &unp3->unp_peercred); 966 unp3->unp_flags |= UNP_HAVEPC; 967 /* 968 * The receiver's (server's) credentials are copied from the 969 * unp_peercred member of socket on which the former called 970 * listen(); unp_listen() cached that process's credentials 971 * at that time so we can use them now. 972 */ 973 KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED, 974 ("unp_connect: listener without cached peercred")); 975 memcpy(&unp->unp_peercred, &unp2->unp_peercred, 976 sizeof(unp->unp_peercred)); 977 unp->unp_flags |= UNP_HAVEPC; 978 if (unp2->unp_flags & UNP_WANTCRED) 979 unp3->unp_flags |= UNP_WANTCRED; 980 #ifdef MAC 981 SOCK_LOCK(so); 982 mac_set_socket_peer_from_socket(so, so3); 983 mac_set_socket_peer_from_socket(so3, so); 984 SOCK_UNLOCK(so); 985 #endif 986 987 so2 = so3; 988 } 989 error = unp_connect2(so, so2, PRU_CONNECT); 990 bad2: 991 UNP_UNLOCK(); 992 mtx_lock(&Giant); 993 bad: 994 mtx_assert(&Giant, MA_OWNED); 995 if (vp != NULL) 996 vput(vp); 997 mtx_unlock(&Giant); 998 free(sa, M_SONAME); 999 UNP_LOCK(); 1000 unp->unp_flags &= ~UNP_CONNECTING; 1001 return (error); 1002 } 1003 1004 static int 1005 unp_connect2(struct socket *so, struct socket *so2, int req) 1006 { 1007 struct unpcb *unp = sotounpcb(so); 1008 struct unpcb *unp2; 1009 1010 UNP_LOCK_ASSERT(); 1011 1012 if (so2->so_type != so->so_type) 1013 return (EPROTOTYPE); 1014 unp2 = sotounpcb(so2); 1015 KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL")); 1016 unp->unp_conn = unp2; 1017 switch (so->so_type) { 1018 1019 case SOCK_DGRAM: 1020 LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink); 1021 soisconnected(so); 1022 break; 1023 1024 case SOCK_STREAM: 1025 unp2->unp_conn = unp; 1026 if (req == PRU_CONNECT && 1027 ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT)) 1028 soisconnecting(so); 1029 else 1030 soisconnected(so); 1031 soisconnected(so2); 1032 break; 1033 1034 default: 1035 panic("unp_connect2"); 1036 } 1037 return (0); 1038 } 1039 1040 static void 1041 unp_disconnect(struct unpcb *unp) 1042 { 1043 struct unpcb *unp2 = unp->unp_conn; 1044 struct socket *so; 1045 1046 UNP_LOCK_ASSERT(); 1047 1048 if (unp2 == NULL) 1049 return; 1050 unp->unp_conn = NULL; 1051 switch (unp->unp_socket->so_type) { 1052 case SOCK_DGRAM: 1053 LIST_REMOVE(unp, unp_reflink); 1054 so = unp->unp_socket; 1055 SOCK_LOCK(so); 1056 so->so_state &= ~SS_ISCONNECTED; 1057 SOCK_UNLOCK(so); 1058 break; 1059 1060 case SOCK_STREAM: 1061 soisdisconnected(unp->unp_socket); 1062 unp2->unp_conn = NULL; 1063 soisdisconnected(unp2->unp_socket); 1064 break; 1065 } 1066 } 1067 1068 /* 1069 * unp_pcblist() assumes that UNIX domain socket memory is never reclaimed by 1070 * the zone (UMA_ZONE_NOFREE), and as such potentially stale pointers are 1071 * safe to reference. It first scans the list of struct unpcb's to generate 1072 * a pointer list, then it rescans its list one entry at a time to 1073 * externalize and copyout. It checks the generation number to see if a 1074 * struct unpcb has been reused, and will skip it if so. 1075 */ 1076 static int 1077 unp_pcblist(SYSCTL_HANDLER_ARGS) 1078 { 1079 int error, i, n; 1080 struct unpcb *unp, **unp_list; 1081 unp_gen_t gencnt; 1082 struct xunpgen *xug; 1083 struct unp_head *head; 1084 struct xunpcb *xu; 1085 1086 head = ((intptr_t)arg1 == SOCK_DGRAM ? &unp_dhead : &unp_shead); 1087 1088 /* 1089 * The process of preparing the PCB list is too time-consuming and 1090 * resource-intensive to repeat twice on every request. 1091 */ 1092 if (req->oldptr == NULL) { 1093 n = unp_count; 1094 req->oldidx = 2 * (sizeof *xug) 1095 + (n + n/8) * sizeof(struct xunpcb); 1096 return (0); 1097 } 1098 1099 if (req->newptr != NULL) 1100 return (EPERM); 1101 1102 /* 1103 * OK, now we're committed to doing something. 1104 */ 1105 xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK); 1106 UNP_LOCK(); 1107 gencnt = unp_gencnt; 1108 n = unp_count; 1109 UNP_UNLOCK(); 1110 1111 xug->xug_len = sizeof *xug; 1112 xug->xug_count = n; 1113 xug->xug_gen = gencnt; 1114 xug->xug_sogen = so_gencnt; 1115 error = SYSCTL_OUT(req, xug, sizeof *xug); 1116 if (error) { 1117 free(xug, M_TEMP); 1118 return (error); 1119 } 1120 1121 unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK); 1122 1123 UNP_LOCK(); 1124 for (unp = LIST_FIRST(head), i = 0; unp && i < n; 1125 unp = LIST_NEXT(unp, unp_link)) { 1126 if (unp->unp_gencnt <= gencnt) { 1127 if (cr_cansee(req->td->td_ucred, 1128 unp->unp_socket->so_cred)) 1129 continue; 1130 unp_list[i++] = unp; 1131 } 1132 } 1133 UNP_UNLOCK(); 1134 n = i; /* In case we lost some during malloc. */ 1135 1136 error = 0; 1137 xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO); 1138 for (i = 0; i < n; i++) { 1139 unp = unp_list[i]; 1140 if (unp->unp_gencnt <= gencnt) { 1141 xu->xu_len = sizeof *xu; 1142 xu->xu_unpp = unp; 1143 /* 1144 * XXX - need more locking here to protect against 1145 * connect/disconnect races for SMP. 1146 */ 1147 if (unp->unp_addr != NULL) 1148 bcopy(unp->unp_addr, &xu->xu_addr, 1149 unp->unp_addr->sun_len); 1150 if (unp->unp_conn != NULL && 1151 unp->unp_conn->unp_addr != NULL) 1152 bcopy(unp->unp_conn->unp_addr, 1153 &xu->xu_caddr, 1154 unp->unp_conn->unp_addr->sun_len); 1155 bcopy(unp, &xu->xu_unp, sizeof *unp); 1156 sotoxsocket(unp->unp_socket, &xu->xu_socket); 1157 error = SYSCTL_OUT(req, xu, sizeof *xu); 1158 } 1159 } 1160 free(xu, M_TEMP); 1161 if (!error) { 1162 /* 1163 * Give the user an updated idea of our state. If the 1164 * generation differs from what we told her before, she knows 1165 * that something happened while we were processing this 1166 * request, and it might be necessary to retry. 1167 */ 1168 xug->xug_gen = unp_gencnt; 1169 xug->xug_sogen = so_gencnt; 1170 xug->xug_count = unp_count; 1171 error = SYSCTL_OUT(req, xug, sizeof *xug); 1172 } 1173 free(unp_list, M_TEMP); 1174 free(xug, M_TEMP); 1175 return (error); 1176 } 1177 1178 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLFLAG_RD, 1179 (caddr_t)(long)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb", 1180 "List of active local datagram sockets"); 1181 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLFLAG_RD, 1182 (caddr_t)(long)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb", 1183 "List of active local stream sockets"); 1184 1185 static void 1186 unp_shutdown(struct unpcb *unp) 1187 { 1188 struct socket *so; 1189 1190 UNP_LOCK_ASSERT(); 1191 1192 if (unp->unp_socket->so_type == SOCK_STREAM && unp->unp_conn && 1193 (so = unp->unp_conn->unp_socket)) 1194 socantrcvmore(so); 1195 } 1196 1197 static void 1198 unp_drop(struct unpcb *unp, int errno) 1199 { 1200 struct socket *so = unp->unp_socket; 1201 1202 UNP_LOCK_ASSERT(); 1203 1204 so->so_error = errno; 1205 unp_disconnect(unp); 1206 } 1207 1208 static void 1209 unp_freerights(struct file **rp, int fdcount) 1210 { 1211 int i; 1212 struct file *fp; 1213 1214 for (i = 0; i < fdcount; i++) { 1215 fp = *rp; 1216 /* 1217 * Zero the pointer before calling unp_discard since it may 1218 * end up in unp_gc().. 1219 * 1220 * XXXRW: This is less true than it used to be. 1221 */ 1222 *rp++ = 0; 1223 unp_discard(fp); 1224 } 1225 } 1226 1227 int 1228 unp_externalize(struct mbuf *control, struct mbuf **controlp) 1229 { 1230 struct thread *td = curthread; /* XXX */ 1231 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1232 int i; 1233 int *fdp; 1234 struct file **rp; 1235 struct file *fp; 1236 void *data; 1237 socklen_t clen = control->m_len, datalen; 1238 int error, newfds; 1239 int f; 1240 u_int newlen; 1241 1242 UNP_UNLOCK_ASSERT(); 1243 1244 error = 0; 1245 if (controlp != NULL) /* controlp == NULL => free control messages */ 1246 *controlp = NULL; 1247 1248 while (cm != NULL) { 1249 if (sizeof(*cm) > clen || cm->cmsg_len > clen) { 1250 error = EINVAL; 1251 break; 1252 } 1253 1254 data = CMSG_DATA(cm); 1255 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1256 1257 if (cm->cmsg_level == SOL_SOCKET 1258 && cm->cmsg_type == SCM_RIGHTS) { 1259 newfds = datalen / sizeof(struct file *); 1260 rp = data; 1261 1262 /* If we're not outputting the descriptors free them. */ 1263 if (error || controlp == NULL) { 1264 unp_freerights(rp, newfds); 1265 goto next; 1266 } 1267 FILEDESC_LOCK(td->td_proc->p_fd); 1268 /* if the new FD's will not fit free them. */ 1269 if (!fdavail(td, newfds)) { 1270 FILEDESC_UNLOCK(td->td_proc->p_fd); 1271 error = EMSGSIZE; 1272 unp_freerights(rp, newfds); 1273 goto next; 1274 } 1275 /* 1276 * Now change each pointer to an fd in the global 1277 * table to an integer that is the index to the local 1278 * fd table entry that we set up to point to the 1279 * global one we are transferring. 1280 */ 1281 newlen = newfds * sizeof(int); 1282 *controlp = sbcreatecontrol(NULL, newlen, 1283 SCM_RIGHTS, SOL_SOCKET); 1284 if (*controlp == NULL) { 1285 FILEDESC_UNLOCK(td->td_proc->p_fd); 1286 error = E2BIG; 1287 unp_freerights(rp, newfds); 1288 goto next; 1289 } 1290 1291 fdp = (int *) 1292 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1293 for (i = 0; i < newfds; i++) { 1294 if (fdalloc(td, 0, &f)) 1295 panic("unp_externalize fdalloc failed"); 1296 fp = *rp++; 1297 td->td_proc->p_fd->fd_ofiles[f] = fp; 1298 FILE_LOCK(fp); 1299 fp->f_msgcount--; 1300 FILE_UNLOCK(fp); 1301 unp_rights--; 1302 *fdp++ = f; 1303 } 1304 FILEDESC_UNLOCK(td->td_proc->p_fd); 1305 } else { 1306 /* We can just copy anything else across. */ 1307 if (error || controlp == NULL) 1308 goto next; 1309 *controlp = sbcreatecontrol(NULL, datalen, 1310 cm->cmsg_type, cm->cmsg_level); 1311 if (*controlp == NULL) { 1312 error = ENOBUFS; 1313 goto next; 1314 } 1315 bcopy(data, 1316 CMSG_DATA(mtod(*controlp, struct cmsghdr *)), 1317 datalen); 1318 } 1319 1320 controlp = &(*controlp)->m_next; 1321 1322 next: 1323 if (CMSG_SPACE(datalen) < clen) { 1324 clen -= CMSG_SPACE(datalen); 1325 cm = (struct cmsghdr *) 1326 ((caddr_t)cm + CMSG_SPACE(datalen)); 1327 } else { 1328 clen = 0; 1329 cm = NULL; 1330 } 1331 } 1332 1333 m_freem(control); 1334 1335 return (error); 1336 } 1337 1338 static void 1339 unp_zone_change(void *tag) 1340 { 1341 1342 uma_zone_set_max(unp_zone, maxsockets); 1343 } 1344 1345 void 1346 unp_init(void) 1347 { 1348 1349 unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL, 1350 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 1351 if (unp_zone == NULL) 1352 panic("unp_init"); 1353 uma_zone_set_max(unp_zone, maxsockets); 1354 EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change, 1355 NULL, EVENTHANDLER_PRI_ANY); 1356 LIST_INIT(&unp_dhead); 1357 LIST_INIT(&unp_shead); 1358 TASK_INIT(&unp_gc_task, 0, unp_gc, NULL); 1359 UNP_LOCK_INIT(); 1360 } 1361 1362 static int 1363 unp_internalize(struct mbuf **controlp, struct thread *td) 1364 { 1365 struct mbuf *control = *controlp; 1366 struct proc *p = td->td_proc; 1367 struct filedesc *fdescp = p->p_fd; 1368 struct cmsghdr *cm = mtod(control, struct cmsghdr *); 1369 struct cmsgcred *cmcred; 1370 struct file **rp; 1371 struct file *fp; 1372 struct timeval *tv; 1373 int i, fd, *fdp; 1374 void *data; 1375 socklen_t clen = control->m_len, datalen; 1376 int error, oldfds; 1377 u_int newlen; 1378 1379 UNP_UNLOCK_ASSERT(); 1380 1381 error = 0; 1382 *controlp = NULL; 1383 1384 while (cm != NULL) { 1385 if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET 1386 || cm->cmsg_len > clen) { 1387 error = EINVAL; 1388 goto out; 1389 } 1390 1391 data = CMSG_DATA(cm); 1392 datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data; 1393 1394 switch (cm->cmsg_type) { 1395 /* 1396 * Fill in credential information. 1397 */ 1398 case SCM_CREDS: 1399 *controlp = sbcreatecontrol(NULL, sizeof(*cmcred), 1400 SCM_CREDS, SOL_SOCKET); 1401 if (*controlp == NULL) { 1402 error = ENOBUFS; 1403 goto out; 1404 } 1405 1406 cmcred = (struct cmsgcred *) 1407 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1408 cmcred->cmcred_pid = p->p_pid; 1409 cmcred->cmcred_uid = td->td_ucred->cr_ruid; 1410 cmcred->cmcred_gid = td->td_ucred->cr_rgid; 1411 cmcred->cmcred_euid = td->td_ucred->cr_uid; 1412 cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups, 1413 CMGROUP_MAX); 1414 for (i = 0; i < cmcred->cmcred_ngroups; i++) 1415 cmcred->cmcred_groups[i] = 1416 td->td_ucred->cr_groups[i]; 1417 break; 1418 1419 case SCM_RIGHTS: 1420 oldfds = datalen / sizeof (int); 1421 /* 1422 * Check that all the FDs passed in refer to legal 1423 * files. If not, reject the entire operation. 1424 */ 1425 fdp = data; 1426 FILEDESC_LOCK(fdescp); 1427 for (i = 0; i < oldfds; i++) { 1428 fd = *fdp++; 1429 if ((unsigned)fd >= fdescp->fd_nfiles || 1430 fdescp->fd_ofiles[fd] == NULL) { 1431 FILEDESC_UNLOCK(fdescp); 1432 error = EBADF; 1433 goto out; 1434 } 1435 fp = fdescp->fd_ofiles[fd]; 1436 if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) { 1437 FILEDESC_UNLOCK(fdescp); 1438 error = EOPNOTSUPP; 1439 goto out; 1440 } 1441 1442 } 1443 /* 1444 * Now replace the integer FDs with pointers to the 1445 * associated global file table entry.. 1446 */ 1447 newlen = oldfds * sizeof(struct file *); 1448 *controlp = sbcreatecontrol(NULL, newlen, 1449 SCM_RIGHTS, SOL_SOCKET); 1450 if (*controlp == NULL) { 1451 FILEDESC_UNLOCK(fdescp); 1452 error = E2BIG; 1453 goto out; 1454 } 1455 1456 fdp = data; 1457 rp = (struct file **) 1458 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1459 for (i = 0; i < oldfds; i++) { 1460 fp = fdescp->fd_ofiles[*fdp++]; 1461 *rp++ = fp; 1462 FILE_LOCK(fp); 1463 fp->f_count++; 1464 fp->f_msgcount++; 1465 FILE_UNLOCK(fp); 1466 unp_rights++; 1467 } 1468 FILEDESC_UNLOCK(fdescp); 1469 break; 1470 1471 case SCM_TIMESTAMP: 1472 *controlp = sbcreatecontrol(NULL, sizeof(*tv), 1473 SCM_TIMESTAMP, SOL_SOCKET); 1474 if (*controlp == NULL) { 1475 error = ENOBUFS; 1476 goto out; 1477 } 1478 tv = (struct timeval *) 1479 CMSG_DATA(mtod(*controlp, struct cmsghdr *)); 1480 microtime(tv); 1481 break; 1482 1483 default: 1484 error = EINVAL; 1485 goto out; 1486 } 1487 1488 controlp = &(*controlp)->m_next; 1489 1490 if (CMSG_SPACE(datalen) < clen) { 1491 clen -= CMSG_SPACE(datalen); 1492 cm = (struct cmsghdr *) 1493 ((caddr_t)cm + CMSG_SPACE(datalen)); 1494 } else { 1495 clen = 0; 1496 cm = NULL; 1497 } 1498 } 1499 1500 out: 1501 m_freem(control); 1502 1503 return (error); 1504 } 1505 1506 struct mbuf * 1507 unp_addsockcred(struct thread *td, struct mbuf *control) 1508 { 1509 struct mbuf *m, *n, *n_prev; 1510 struct sockcred *sc; 1511 const struct cmsghdr *cm; 1512 int ngroups; 1513 int i; 1514 1515 ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX); 1516 1517 m = sbcreatecontrol(NULL, SOCKCREDSIZE(ngroups), SCM_CREDS, SOL_SOCKET); 1518 if (m == NULL) 1519 return (control); 1520 1521 sc = (struct sockcred *) CMSG_DATA(mtod(m, struct cmsghdr *)); 1522 sc->sc_uid = td->td_ucred->cr_ruid; 1523 sc->sc_euid = td->td_ucred->cr_uid; 1524 sc->sc_gid = td->td_ucred->cr_rgid; 1525 sc->sc_egid = td->td_ucred->cr_gid; 1526 sc->sc_ngroups = ngroups; 1527 for (i = 0; i < sc->sc_ngroups; i++) 1528 sc->sc_groups[i] = td->td_ucred->cr_groups[i]; 1529 1530 /* 1531 * Unlink SCM_CREDS control messages (struct cmsgcred), since just 1532 * created SCM_CREDS control message (struct sockcred) has another 1533 * format. 1534 */ 1535 if (control != NULL) 1536 for (n = control, n_prev = NULL; n != NULL;) { 1537 cm = mtod(n, struct cmsghdr *); 1538 if (cm->cmsg_level == SOL_SOCKET && 1539 cm->cmsg_type == SCM_CREDS) { 1540 if (n_prev == NULL) 1541 control = n->m_next; 1542 else 1543 n_prev->m_next = n->m_next; 1544 n = m_free(n); 1545 } else { 1546 n_prev = n; 1547 n = n->m_next; 1548 } 1549 } 1550 1551 /* Prepend it to the head. */ 1552 m->m_next = control; 1553 1554 return (m); 1555 } 1556 1557 /* 1558 * unp_defer indicates whether additional work has been defered for a future 1559 * pass through unp_gc(). It is thread local and does not require explicit 1560 * synchronization. 1561 */ 1562 static int unp_defer; 1563 1564 static int unp_taskcount; 1565 SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0, ""); 1566 1567 static int unp_recycled; 1568 SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0, ""); 1569 1570 static void 1571 unp_gc(__unused void *arg, int pending) 1572 { 1573 struct file *fp, *nextfp; 1574 struct socket *so; 1575 struct file **extra_ref, **fpp; 1576 int nunref, i; 1577 int nfiles_snap; 1578 int nfiles_slack = 20; 1579 1580 unp_taskcount++; 1581 unp_defer = 0; 1582 /* 1583 * Before going through all this, set all FDs to be NOT defered and 1584 * NOT externally accessible. 1585 */ 1586 sx_slock(&filelist_lock); 1587 LIST_FOREACH(fp, &filehead, f_list) 1588 fp->f_gcflag &= ~(FMARK|FDEFER); 1589 do { 1590 KASSERT(unp_defer >= 0, ("unp_gc: unp_defer %d", unp_defer)); 1591 LIST_FOREACH(fp, &filehead, f_list) { 1592 FILE_LOCK(fp); 1593 /* 1594 * If the file is not open, skip it -- could be a 1595 * file in the process of being opened, or in the 1596 * process of being closed. If the file is 1597 * "closing", it may have been marked for deferred 1598 * consideration. Clear the flag now if so. 1599 */ 1600 if (fp->f_count == 0) { 1601 if (fp->f_gcflag & FDEFER) 1602 unp_defer--; 1603 fp->f_gcflag &= ~(FMARK|FDEFER); 1604 FILE_UNLOCK(fp); 1605 continue; 1606 } 1607 /* 1608 * If we already marked it as 'defer' in a previous 1609 * pass, then try process it this time and un-mark 1610 * it. 1611 */ 1612 if (fp->f_gcflag & FDEFER) { 1613 fp->f_gcflag &= ~FDEFER; 1614 unp_defer--; 1615 } else { 1616 /* 1617 * if it's not defered, then check if it's 1618 * already marked.. if so skip it 1619 */ 1620 if (fp->f_gcflag & FMARK) { 1621 FILE_UNLOCK(fp); 1622 continue; 1623 } 1624 /* 1625 * If all references are from messages in 1626 * transit, then skip it. it's not externally 1627 * accessible. 1628 */ 1629 if (fp->f_count == fp->f_msgcount) { 1630 FILE_UNLOCK(fp); 1631 continue; 1632 } 1633 /* 1634 * If it got this far then it must be 1635 * externally accessible. 1636 */ 1637 fp->f_gcflag |= FMARK; 1638 } 1639 /* 1640 * Either it was defered, or it is externally 1641 * accessible and not already marked so. Now check 1642 * if it is possibly one of OUR sockets. 1643 */ 1644 if (fp->f_type != DTYPE_SOCKET || 1645 (so = fp->f_data) == NULL) { 1646 FILE_UNLOCK(fp); 1647 continue; 1648 } 1649 FILE_UNLOCK(fp); 1650 if (so->so_proto->pr_domain != &localdomain || 1651 (so->so_proto->pr_flags&PR_RIGHTS) == 0) 1652 continue; 1653 /* 1654 * So, Ok, it's one of our sockets and it IS 1655 * externally accessible (or was defered). Now we 1656 * look to see if we hold any file descriptors in its 1657 * message buffers. Follow those links and mark them 1658 * as accessible too. 1659 */ 1660 SOCKBUF_LOCK(&so->so_rcv); 1661 unp_scan(so->so_rcv.sb_mb, unp_mark); 1662 SOCKBUF_UNLOCK(&so->so_rcv); 1663 } 1664 } while (unp_defer); 1665 sx_sunlock(&filelist_lock); 1666 /* 1667 * XXXRW: The following comments need updating for a post-SMPng and 1668 * deferred unp_gc() world, but are still generally accurate. 1669 * 1670 * We grab an extra reference to each of the file table entries that 1671 * are not otherwise accessible and then free the rights that are 1672 * stored in messages on them. 1673 * 1674 * The bug in the orginal code is a little tricky, so I'll describe 1675 * what's wrong with it here. 1676 * 1677 * It is incorrect to simply unp_discard each entry for f_msgcount 1678 * times -- consider the case of sockets A and B that contain 1679 * references to each other. On a last close of some other socket, 1680 * we trigger a gc since the number of outstanding rights (unp_rights) 1681 * is non-zero. If during the sweep phase the gc code unp_discards, 1682 * we end up doing a (full) closef on the descriptor. A closef on A 1683 * results in the following chain. Closef calls soo_close, which 1684 * calls soclose. Soclose calls first (through the switch 1685 * uipc_usrreq) unp_detach, which re-invokes unp_gc. Unp_gc simply 1686 * returns because the previous instance had set unp_gcing, and we 1687 * return all the way back to soclose, which marks the socket with 1688 * SS_NOFDREF, and then calls sofree. Sofree calls sorflush to free 1689 * up the rights that are queued in messages on the socket A, i.e., 1690 * the reference on B. The sorflush calls via the dom_dispose switch 1691 * unp_dispose, which unp_scans with unp_discard. This second 1692 * instance of unp_discard just calls closef on B. 1693 * 1694 * Well, a similar chain occurs on B, resulting in a sorflush on B, 1695 * which results in another closef on A. Unfortunately, A is already 1696 * being closed, and the descriptor has already been marked with 1697 * SS_NOFDREF, and soclose panics at this point. 1698 * 1699 * Here, we first take an extra reference to each inaccessible 1700 * descriptor. Then, we call sorflush ourself, since we know it is a 1701 * Unix domain socket anyhow. After we destroy all the rights 1702 * carried in messages, we do a last closef to get rid of our extra 1703 * reference. This is the last close, and the unp_detach etc will 1704 * shut down the socket. 1705 * 1706 * 91/09/19, bsy@cs.cmu.edu 1707 */ 1708 again: 1709 nfiles_snap = openfiles + nfiles_slack; /* some slack */ 1710 extra_ref = malloc(nfiles_snap * sizeof(struct file *), M_TEMP, 1711 M_WAITOK); 1712 sx_slock(&filelist_lock); 1713 if (nfiles_snap < openfiles) { 1714 sx_sunlock(&filelist_lock); 1715 free(extra_ref, M_TEMP); 1716 nfiles_slack += 20; 1717 goto again; 1718 } 1719 for (nunref = 0, fp = LIST_FIRST(&filehead), fpp = extra_ref; 1720 fp != NULL; fp = nextfp) { 1721 nextfp = LIST_NEXT(fp, f_list); 1722 FILE_LOCK(fp); 1723 /* 1724 * If it's not open, skip it 1725 */ 1726 if (fp->f_count == 0) { 1727 FILE_UNLOCK(fp); 1728 continue; 1729 } 1730 /* 1731 * If all refs are from msgs, and it's not marked accessible 1732 * then it must be referenced from some unreachable cycle of 1733 * (shut-down) FDs, so include it in our list of FDs to 1734 * remove. 1735 */ 1736 if (fp->f_count == fp->f_msgcount && !(fp->f_gcflag & FMARK)) { 1737 *fpp++ = fp; 1738 nunref++; 1739 fp->f_count++; 1740 } 1741 FILE_UNLOCK(fp); 1742 } 1743 sx_sunlock(&filelist_lock); 1744 /* 1745 * For each FD on our hit list, do the following two things: 1746 */ 1747 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 1748 struct file *tfp = *fpp; 1749 FILE_LOCK(tfp); 1750 if (tfp->f_type == DTYPE_SOCKET && 1751 tfp->f_data != NULL) { 1752 FILE_UNLOCK(tfp); 1753 sorflush(tfp->f_data); 1754 } else { 1755 FILE_UNLOCK(tfp); 1756 } 1757 } 1758 for (i = nunref, fpp = extra_ref; --i >= 0; ++fpp) { 1759 closef(*fpp, (struct thread *) NULL); 1760 unp_recycled++; 1761 } 1762 free(extra_ref, M_TEMP); 1763 } 1764 1765 void 1766 unp_dispose(struct mbuf *m) 1767 { 1768 1769 if (m) 1770 unp_scan(m, unp_discard); 1771 } 1772 1773 static int 1774 unp_listen(struct socket *so, struct unpcb *unp, int backlog, 1775 struct thread *td) 1776 { 1777 int error; 1778 1779 UNP_LOCK_ASSERT(); 1780 1781 SOCK_LOCK(so); 1782 error = solisten_proto_check(so); 1783 if (error == 0) { 1784 cru2x(td->td_ucred, &unp->unp_peercred); 1785 unp->unp_flags |= UNP_HAVEPCCACHED; 1786 solisten_proto(so, backlog); 1787 } 1788 SOCK_UNLOCK(so); 1789 return (error); 1790 } 1791 1792 static void 1793 unp_scan(struct mbuf *m0, void (*op)(struct file *)) 1794 { 1795 struct mbuf *m; 1796 struct file **rp; 1797 struct cmsghdr *cm; 1798 void *data; 1799 int i; 1800 socklen_t clen, datalen; 1801 int qfds; 1802 1803 while (m0 != NULL) { 1804 for (m = m0; m; m = m->m_next) { 1805 if (m->m_type != MT_CONTROL) 1806 continue; 1807 1808 cm = mtod(m, struct cmsghdr *); 1809 clen = m->m_len; 1810 1811 while (cm != NULL) { 1812 if (sizeof(*cm) > clen || cm->cmsg_len > clen) 1813 break; 1814 1815 data = CMSG_DATA(cm); 1816 datalen = (caddr_t)cm + cm->cmsg_len 1817 - (caddr_t)data; 1818 1819 if (cm->cmsg_level == SOL_SOCKET && 1820 cm->cmsg_type == SCM_RIGHTS) { 1821 qfds = datalen / sizeof (struct file *); 1822 rp = data; 1823 for (i = 0; i < qfds; i++) 1824 (*op)(*rp++); 1825 } 1826 1827 if (CMSG_SPACE(datalen) < clen) { 1828 clen -= CMSG_SPACE(datalen); 1829 cm = (struct cmsghdr *) 1830 ((caddr_t)cm + CMSG_SPACE(datalen)); 1831 } else { 1832 clen = 0; 1833 cm = NULL; 1834 } 1835 } 1836 } 1837 m0 = m0->m_act; 1838 } 1839 } 1840 1841 static void 1842 unp_mark(struct file *fp) 1843 { 1844 if (fp->f_gcflag & FMARK) 1845 return; 1846 unp_defer++; 1847 fp->f_gcflag |= (FMARK|FDEFER); 1848 } 1849 1850 static void 1851 unp_discard(struct file *fp) 1852 { 1853 UNP_LOCK(); 1854 FILE_LOCK(fp); 1855 fp->f_msgcount--; 1856 unp_rights--; 1857 FILE_UNLOCK(fp); 1858 UNP_UNLOCK(); 1859 (void) closef(fp, (struct thread *)NULL); 1860 } 1861