1 /* $NetBSD: uipc_usrreq.c,v 1.146 2013/10/08 17:21:24 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2000, 2004, 2008, 2009 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center, and by Andrew Doran. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 1982, 1986, 1989, 1991, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 3. Neither the name of the University nor the names of its contributors 46 * may be used to endorse or promote products derived from this software 47 * without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 * 61 * @(#)uipc_usrreq.c 8.9 (Berkeley) 5/14/95 62 */ 63 64 /* 65 * Copyright (c) 1997 Christopher G. Demetriou. All rights reserved. 66 * 67 * Redistribution and use in source and binary forms, with or without 68 * modification, are permitted provided that the following conditions 69 * are met: 70 * 1. Redistributions of source code must retain the above copyright 71 * notice, this list of conditions and the following disclaimer. 72 * 2. Redistributions in binary form must reproduce the above copyright 73 * notice, this list of conditions and the following disclaimer in the 74 * documentation and/or other materials provided with the distribution. 75 * 3. All advertising materials mentioning features or use of this software 76 * must display the following acknowledgement: 77 * This product includes software developed by the University of 78 * California, Berkeley and its contributors. 79 * 4. Neither the name of the University nor the names of its contributors 80 * may be used to endorse or promote products derived from this software 81 * without specific prior written permission. 82 * 83 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 84 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 85 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 86 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 87 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 88 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 89 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 90 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 91 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 92 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 93 * SUCH DAMAGE. 94 * 95 * @(#)uipc_usrreq.c 8.9 (Berkeley) 5/14/95 96 */ 97 98 #include <sys/cdefs.h> 99 __KERNEL_RCSID(0, "$NetBSD: uipc_usrreq.c,v 1.146 2013/10/08 17:21:24 christos Exp $"); 100 101 #include <sys/param.h> 102 #include <sys/systm.h> 103 #include <sys/proc.h> 104 #include <sys/filedesc.h> 105 #include <sys/domain.h> 106 #include <sys/protosw.h> 107 #include <sys/socket.h> 108 #include <sys/socketvar.h> 109 #include <sys/unpcb.h> 110 #include <sys/un.h> 111 #include <sys/namei.h> 112 #include <sys/vnode.h> 113 #include <sys/file.h> 114 #include <sys/stat.h> 115 #include <sys/mbuf.h> 116 #include <sys/kauth.h> 117 #include <sys/kmem.h> 118 #include <sys/atomic.h> 119 #include <sys/uidinfo.h> 120 #include <sys/kernel.h> 121 #include <sys/kthread.h> 122 123 /* 124 * Unix communications domain. 125 * 126 * TODO: 127 * RDM 128 * rethink name space problems 129 * need a proper out-of-band 130 * 131 * Notes on locking: 132 * 133 * The generic rules noted in uipc_socket2.c apply. In addition: 134 * 135 * o We have a global lock, uipc_lock. 136 * 137 * o All datagram sockets are locked by uipc_lock. 138 * 139 * o For stream socketpairs, the two endpoints are created sharing the same 140 * independent lock. Sockets presented to PRU_CONNECT2 must already have 141 * matching locks. 142 * 143 * o Stream sockets created via socket() start life with their own 144 * independent lock. 145 * 146 * o Stream connections to a named endpoint are slightly more complicated. 147 * Sockets that have called listen() have their lock pointer mutated to 148 * the global uipc_lock. When establishing a connection, the connecting 149 * socket also has its lock mutated to uipc_lock, which matches the head 150 * (listening socket). We create a new socket for accept() to return, and 151 * that also shares the head's lock. Until the connection is completely 152 * done on both ends, all three sockets are locked by uipc_lock. Once the 153 * connection is complete, the association with the head's lock is broken. 154 * The connecting socket and the socket returned from accept() have their 155 * lock pointers mutated away from uipc_lock, and back to the connecting 156 * socket's original, independent lock. The head continues to be locked 157 * by uipc_lock. 158 * 159 * o If uipc_lock is determined to be a significant source of contention, 160 * it could easily be hashed out. It is difficult to simply make it an 161 * independent lock because of visibility / garbage collection issues: 162 * if a socket has been associated with a lock at any point, that lock 163 * must remain valid until the socket is no longer visible in the system. 164 * The lock must not be freed or otherwise destroyed until any sockets 165 * that had referenced it have also been destroyed. 166 */ 167 const struct sockaddr_un sun_noname = { 168 .sun_len = offsetof(struct sockaddr_un, sun_path), 169 .sun_family = AF_LOCAL, 170 }; 171 ino_t unp_ino; /* prototype for fake inode numbers */ 172 173 struct mbuf *unp_addsockcred(struct lwp *, struct mbuf *); 174 static void unp_mark(file_t *); 175 static void unp_scan(struct mbuf *, void (*)(file_t *), int); 176 static void unp_discard_now(file_t *); 177 static void unp_discard_later(file_t *); 178 static void unp_thread(void *); 179 static void unp_thread_kick(void); 180 static kmutex_t *uipc_lock; 181 182 static kcondvar_t unp_thread_cv; 183 static lwp_t *unp_thread_lwp; 184 static SLIST_HEAD(,file) unp_thread_discard; 185 static int unp_defer; 186 187 /* 188 * Initialize Unix protocols. 189 */ 190 void 191 uipc_init(void) 192 { 193 int error; 194 195 uipc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE); 196 cv_init(&unp_thread_cv, "unpgc"); 197 198 error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL, unp_thread, 199 NULL, &unp_thread_lwp, "unpgc"); 200 if (error != 0) 201 panic("uipc_init %d", error); 202 } 203 204 /* 205 * A connection succeeded: disassociate both endpoints from the head's 206 * lock, and make them share their own lock. There is a race here: for 207 * a very brief time one endpoint will be locked by a different lock 208 * than the other end. However, since the current thread holds the old 209 * lock (the listening socket's lock, the head) access can still only be 210 * made to one side of the connection. 211 */ 212 static void 213 unp_setpeerlocks(struct socket *so, struct socket *so2) 214 { 215 struct unpcb *unp; 216 kmutex_t *lock; 217 218 KASSERT(solocked2(so, so2)); 219 220 /* 221 * Bail out if either end of the socket is not yet fully 222 * connected or accepted. We only break the lock association 223 * with the head when the pair of sockets stand completely 224 * on their own. 225 */ 226 KASSERT(so->so_head == NULL); 227 if (so2->so_head != NULL) 228 return; 229 230 /* 231 * Drop references to old lock. A third reference (from the 232 * queue head) must be held as we still hold its lock. Bonus: 233 * we don't need to worry about garbage collecting the lock. 234 */ 235 lock = so->so_lock; 236 KASSERT(lock == uipc_lock); 237 mutex_obj_free(lock); 238 mutex_obj_free(lock); 239 240 /* 241 * Grab stream lock from the initiator and share between the two 242 * endpoints. Issue memory barrier to ensure all modifications 243 * become globally visible before the lock change. so2 is 244 * assumed not to have a stream lock, because it was created 245 * purely for the server side to accept this connection and 246 * started out life using the domain-wide lock. 247 */ 248 unp = sotounpcb(so); 249 KASSERT(unp->unp_streamlock != NULL); 250 KASSERT(sotounpcb(so2)->unp_streamlock == NULL); 251 lock = unp->unp_streamlock; 252 unp->unp_streamlock = NULL; 253 mutex_obj_hold(lock); 254 membar_exit(); 255 /* 256 * possible race if lock is not held - see comment in 257 * uipc_usrreq(PRU_ACCEPT). 258 */ 259 KASSERT(mutex_owned(lock)); 260 solockreset(so, lock); 261 solockreset(so2, lock); 262 } 263 264 /* 265 * Reset a socket's lock back to the domain-wide lock. 266 */ 267 static void 268 unp_resetlock(struct socket *so) 269 { 270 kmutex_t *olock, *nlock; 271 struct unpcb *unp; 272 273 KASSERT(solocked(so)); 274 275 olock = so->so_lock; 276 nlock = uipc_lock; 277 if (olock == nlock) 278 return; 279 unp = sotounpcb(so); 280 KASSERT(unp->unp_streamlock == NULL); 281 unp->unp_streamlock = olock; 282 mutex_obj_hold(nlock); 283 mutex_enter(nlock); 284 solockreset(so, nlock); 285 mutex_exit(olock); 286 } 287 288 static void 289 unp_free(struct unpcb *unp) 290 { 291 292 if (unp->unp_addr) 293 free(unp->unp_addr, M_SONAME); 294 if (unp->unp_streamlock != NULL) 295 mutex_obj_free(unp->unp_streamlock); 296 free(unp, M_PCB); 297 } 298 299 int 300 unp_output(struct mbuf *m, struct mbuf *control, struct unpcb *unp, 301 struct lwp *l) 302 { 303 struct socket *so2; 304 const struct sockaddr_un *sun; 305 306 so2 = unp->unp_conn->unp_socket; 307 308 KASSERT(solocked(so2)); 309 310 if (unp->unp_addr) 311 sun = unp->unp_addr; 312 else 313 sun = &sun_noname; 314 if (unp->unp_conn->unp_flags & UNP_WANTCRED) 315 control = unp_addsockcred(l, control); 316 if (sbappendaddr(&so2->so_rcv, (const struct sockaddr *)sun, m, 317 control) == 0) { 318 so2->so_rcv.sb_overflowed++; 319 unp_dispose(control); 320 m_freem(control); 321 m_freem(m); 322 return (ENOBUFS); 323 } else { 324 sorwakeup(so2); 325 return (0); 326 } 327 } 328 329 void 330 unp_setaddr(struct socket *so, struct mbuf *nam, bool peeraddr) 331 { 332 const struct sockaddr_un *sun; 333 struct unpcb *unp; 334 bool ext; 335 336 KASSERT(solocked(so)); 337 unp = sotounpcb(so); 338 ext = false; 339 340 for (;;) { 341 sun = NULL; 342 if (peeraddr) { 343 if (unp->unp_conn && unp->unp_conn->unp_addr) 344 sun = unp->unp_conn->unp_addr; 345 } else { 346 if (unp->unp_addr) 347 sun = unp->unp_addr; 348 } 349 if (sun == NULL) 350 sun = &sun_noname; 351 nam->m_len = sun->sun_len; 352 if (nam->m_len > MLEN && !ext) { 353 sounlock(so); 354 MEXTMALLOC(nam, MAXPATHLEN * 2, M_WAITOK); 355 solock(so); 356 ext = true; 357 } else { 358 KASSERT(nam->m_len <= MAXPATHLEN * 2); 359 memcpy(mtod(nam, void *), sun, (size_t)nam->m_len); 360 break; 361 } 362 } 363 } 364 365 /*ARGSUSED*/ 366 int 367 uipc_usrreq(struct socket *so, int req, struct mbuf *m, struct mbuf *nam, 368 struct mbuf *control, struct lwp *l) 369 { 370 struct unpcb *unp = sotounpcb(so); 371 struct socket *so2; 372 struct proc *p; 373 u_int newhiwat; 374 int error = 0; 375 376 if (req == PRU_CONTROL) 377 return (EOPNOTSUPP); 378 379 #ifdef DIAGNOSTIC 380 if (req != PRU_SEND && req != PRU_SENDOOB && control) 381 panic("uipc_usrreq: unexpected control mbuf"); 382 #endif 383 p = l ? l->l_proc : NULL; 384 if (req != PRU_ATTACH) { 385 if (unp == NULL) { 386 error = EINVAL; 387 goto release; 388 } 389 KASSERT(solocked(so)); 390 } 391 392 switch (req) { 393 394 case PRU_ATTACH: 395 if (unp != NULL) { 396 error = EISCONN; 397 break; 398 } 399 error = unp_attach(so); 400 break; 401 402 case PRU_DETACH: 403 unp_detach(unp); 404 break; 405 406 case PRU_BIND: 407 KASSERT(l != NULL); 408 error = unp_bind(so, nam, l); 409 break; 410 411 case PRU_LISTEN: 412 /* 413 * If the socket can accept a connection, it must be 414 * locked by uipc_lock. 415 */ 416 unp_resetlock(so); 417 if (unp->unp_vnode == NULL) 418 error = EINVAL; 419 break; 420 421 case PRU_CONNECT: 422 KASSERT(l != NULL); 423 error = unp_connect(so, nam, l); 424 break; 425 426 case PRU_CONNECT2: 427 error = unp_connect2(so, (struct socket *)nam, PRU_CONNECT2); 428 break; 429 430 case PRU_DISCONNECT: 431 unp_disconnect(unp); 432 break; 433 434 case PRU_ACCEPT: 435 KASSERT(so->so_lock == uipc_lock); 436 /* 437 * Mark the initiating STREAM socket as connected *ONLY* 438 * after it's been accepted. This prevents a client from 439 * overrunning a server and receiving ECONNREFUSED. 440 */ 441 if (unp->unp_conn == NULL) { 442 /* 443 * This will use the empty socket and will not 444 * allocate. 445 */ 446 unp_setaddr(so, nam, true); 447 break; 448 } 449 so2 = unp->unp_conn->unp_socket; 450 if (so2->so_state & SS_ISCONNECTING) { 451 KASSERT(solocked2(so, so->so_head)); 452 KASSERT(solocked2(so2, so->so_head)); 453 soisconnected(so2); 454 } 455 /* 456 * If the connection is fully established, break the 457 * association with uipc_lock and give the connected 458 * pair a seperate lock to share. 459 * There is a race here: sotounpcb(so2)->unp_streamlock 460 * is not locked, so when changing so2->so_lock 461 * another thread can grab it while so->so_lock is still 462 * pointing to the (locked) uipc_lock. 463 * this should be harmless, except that this makes 464 * solocked2() and solocked() unreliable. 465 * Another problem is that unp_setaddr() expects the 466 * the socket locked. Grabing sotounpcb(so2)->unp_streamlock 467 * fixes both issues. 468 */ 469 mutex_enter(sotounpcb(so2)->unp_streamlock); 470 unp_setpeerlocks(so2, so); 471 /* 472 * Only now return peer's address, as we may need to 473 * block in order to allocate memory. 474 * 475 * XXX Minor race: connection can be broken while 476 * lock is dropped in unp_setaddr(). We will return 477 * error == 0 and sun_noname as the peer address. 478 */ 479 unp_setaddr(so, nam, true); 480 /* so_lock now points to unp_streamlock */ 481 mutex_exit(so2->so_lock); 482 break; 483 484 case PRU_SHUTDOWN: 485 socantsendmore(so); 486 unp_shutdown(unp); 487 break; 488 489 case PRU_RCVD: 490 switch (so->so_type) { 491 492 case SOCK_DGRAM: 493 panic("uipc 1"); 494 /*NOTREACHED*/ 495 496 case SOCK_SEQPACKET: /* FALLTHROUGH */ 497 case SOCK_STREAM: 498 #define rcv (&so->so_rcv) 499 #define snd (&so2->so_snd) 500 if (unp->unp_conn == 0) 501 break; 502 so2 = unp->unp_conn->unp_socket; 503 KASSERT(solocked2(so, so2)); 504 /* 505 * Adjust backpressure on sender 506 * and wakeup any waiting to write. 507 */ 508 snd->sb_mbmax += unp->unp_mbcnt - rcv->sb_mbcnt; 509 unp->unp_mbcnt = rcv->sb_mbcnt; 510 newhiwat = snd->sb_hiwat + unp->unp_cc - rcv->sb_cc; 511 (void)chgsbsize(so2->so_uidinfo, 512 &snd->sb_hiwat, newhiwat, RLIM_INFINITY); 513 unp->unp_cc = rcv->sb_cc; 514 sowwakeup(so2); 515 #undef snd 516 #undef rcv 517 break; 518 519 default: 520 panic("uipc 2"); 521 } 522 break; 523 524 case PRU_SEND: 525 /* 526 * Note: unp_internalize() rejects any control message 527 * other than SCM_RIGHTS, and only allows one. This 528 * has the side-effect of preventing a caller from 529 * forging SCM_CREDS. 530 */ 531 if (control) { 532 sounlock(so); 533 error = unp_internalize(&control); 534 solock(so); 535 if (error != 0) { 536 m_freem(control); 537 m_freem(m); 538 break; 539 } 540 } 541 switch (so->so_type) { 542 543 case SOCK_DGRAM: { 544 KASSERT(so->so_lock == uipc_lock); 545 if (nam) { 546 if ((so->so_state & SS_ISCONNECTED) != 0) 547 error = EISCONN; 548 else { 549 /* 550 * Note: once connected, the 551 * socket's lock must not be 552 * dropped until we have sent 553 * the message and disconnected. 554 * This is necessary to prevent 555 * intervening control ops, like 556 * another connection. 557 */ 558 error = unp_connect(so, nam, l); 559 } 560 } else { 561 if ((so->so_state & SS_ISCONNECTED) == 0) 562 error = ENOTCONN; 563 } 564 if (error) { 565 unp_dispose(control); 566 m_freem(control); 567 m_freem(m); 568 break; 569 } 570 KASSERT(p != NULL); 571 error = unp_output(m, control, unp, l); 572 if (nam) 573 unp_disconnect(unp); 574 break; 575 } 576 577 case SOCK_SEQPACKET: /* FALLTHROUGH */ 578 case SOCK_STREAM: 579 #define rcv (&so2->so_rcv) 580 #define snd (&so->so_snd) 581 if (unp->unp_conn == NULL) { 582 error = ENOTCONN; 583 break; 584 } 585 so2 = unp->unp_conn->unp_socket; 586 KASSERT(solocked2(so, so2)); 587 if (unp->unp_conn->unp_flags & UNP_WANTCRED) { 588 /* 589 * Credentials are passed only once on 590 * SOCK_STREAM and SOCK_SEQPACKET. 591 */ 592 unp->unp_conn->unp_flags &= ~UNP_WANTCRED; 593 control = unp_addsockcred(l, control); 594 } 595 /* 596 * Send to paired receive port, and then reduce 597 * send buffer hiwater marks to maintain backpressure. 598 * Wake up readers. 599 */ 600 if (control) { 601 if (sbappendcontrol(rcv, m, control) != 0) 602 control = NULL; 603 } else { 604 switch(so->so_type) { 605 case SOCK_SEQPACKET: 606 sbappendrecord(rcv, m); 607 break; 608 case SOCK_STREAM: 609 sbappend(rcv, m); 610 break; 611 default: 612 panic("uipc_usrreq"); 613 break; 614 } 615 } 616 snd->sb_mbmax -= 617 rcv->sb_mbcnt - unp->unp_conn->unp_mbcnt; 618 unp->unp_conn->unp_mbcnt = rcv->sb_mbcnt; 619 newhiwat = snd->sb_hiwat - 620 (rcv->sb_cc - unp->unp_conn->unp_cc); 621 (void)chgsbsize(so->so_uidinfo, 622 &snd->sb_hiwat, newhiwat, RLIM_INFINITY); 623 unp->unp_conn->unp_cc = rcv->sb_cc; 624 sorwakeup(so2); 625 #undef snd 626 #undef rcv 627 if (control != NULL) { 628 unp_dispose(control); 629 m_freem(control); 630 } 631 break; 632 633 default: 634 panic("uipc 4"); 635 } 636 break; 637 638 case PRU_ABORT: 639 (void)unp_drop(unp, ECONNABORTED); 640 641 KASSERT(so->so_head == NULL); 642 #ifdef DIAGNOSTIC 643 if (so->so_pcb == NULL) 644 panic("uipc 5: drop killed pcb"); 645 #endif 646 unp_detach(unp); 647 break; 648 649 case PRU_SENSE: 650 ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat; 651 switch (so->so_type) { 652 case SOCK_SEQPACKET: /* FALLTHROUGH */ 653 case SOCK_STREAM: 654 if (unp->unp_conn == 0) 655 break; 656 657 so2 = unp->unp_conn->unp_socket; 658 KASSERT(solocked2(so, so2)); 659 ((struct stat *) m)->st_blksize += so2->so_rcv.sb_cc; 660 break; 661 default: 662 break; 663 } 664 ((struct stat *) m)->st_dev = NODEV; 665 if (unp->unp_ino == 0) 666 unp->unp_ino = unp_ino++; 667 ((struct stat *) m)->st_atimespec = 668 ((struct stat *) m)->st_mtimespec = 669 ((struct stat *) m)->st_ctimespec = unp->unp_ctime; 670 ((struct stat *) m)->st_ino = unp->unp_ino; 671 return (0); 672 673 case PRU_RCVOOB: 674 error = EOPNOTSUPP; 675 break; 676 677 case PRU_SENDOOB: 678 m_freem(control); 679 m_freem(m); 680 error = EOPNOTSUPP; 681 break; 682 683 case PRU_SOCKADDR: 684 unp_setaddr(so, nam, false); 685 break; 686 687 case PRU_PEERADDR: 688 unp_setaddr(so, nam, true); 689 break; 690 691 default: 692 panic("piusrreq"); 693 } 694 695 release: 696 return (error); 697 } 698 699 /* 700 * Unix domain socket option processing. 701 */ 702 int 703 uipc_ctloutput(int op, struct socket *so, struct sockopt *sopt) 704 { 705 struct unpcb *unp = sotounpcb(so); 706 int optval = 0, error = 0; 707 708 KASSERT(solocked(so)); 709 710 if (sopt->sopt_level != 0) { 711 error = ENOPROTOOPT; 712 } else switch (op) { 713 714 case PRCO_SETOPT: 715 switch (sopt->sopt_name) { 716 case LOCAL_CREDS: 717 case LOCAL_CONNWAIT: 718 error = sockopt_getint(sopt, &optval); 719 if (error) 720 break; 721 switch (sopt->sopt_name) { 722 #define OPTSET(bit) \ 723 if (optval) \ 724 unp->unp_flags |= (bit); \ 725 else \ 726 unp->unp_flags &= ~(bit); 727 728 case LOCAL_CREDS: 729 OPTSET(UNP_WANTCRED); 730 break; 731 case LOCAL_CONNWAIT: 732 OPTSET(UNP_CONNWAIT); 733 break; 734 } 735 break; 736 #undef OPTSET 737 738 default: 739 error = ENOPROTOOPT; 740 break; 741 } 742 break; 743 744 case PRCO_GETOPT: 745 sounlock(so); 746 switch (sopt->sopt_name) { 747 case LOCAL_PEEREID: 748 if (unp->unp_flags & UNP_EIDSVALID) { 749 error = sockopt_set(sopt, 750 &unp->unp_connid, sizeof(unp->unp_connid)); 751 } else { 752 error = EINVAL; 753 } 754 break; 755 case LOCAL_CREDS: 756 #define OPTBIT(bit) (unp->unp_flags & (bit) ? 1 : 0) 757 758 optval = OPTBIT(UNP_WANTCRED); 759 error = sockopt_setint(sopt, optval); 760 break; 761 #undef OPTBIT 762 763 default: 764 error = ENOPROTOOPT; 765 break; 766 } 767 solock(so); 768 break; 769 } 770 return (error); 771 } 772 773 /* 774 * Both send and receive buffers are allocated PIPSIZ bytes of buffering 775 * for stream sockets, although the total for sender and receiver is 776 * actually only PIPSIZ. 777 * Datagram sockets really use the sendspace as the maximum datagram size, 778 * and don't really want to reserve the sendspace. Their recvspace should 779 * be large enough for at least one max-size datagram plus address. 780 */ 781 #define PIPSIZ 4096 782 u_long unpst_sendspace = PIPSIZ; 783 u_long unpst_recvspace = PIPSIZ; 784 u_long unpdg_sendspace = 2*1024; /* really max datagram size */ 785 u_long unpdg_recvspace = 4*1024; 786 787 u_int unp_rights; /* files in flight */ 788 u_int unp_rights_ratio = 2; /* limit, fraction of maxfiles */ 789 790 int 791 unp_attach(struct socket *so) 792 { 793 struct unpcb *unp; 794 int error; 795 796 switch (so->so_type) { 797 case SOCK_SEQPACKET: /* FALLTHROUGH */ 798 case SOCK_STREAM: 799 if (so->so_lock == NULL) { 800 /* 801 * XXX Assuming that no socket locks are held, 802 * as this call may sleep. 803 */ 804 so->so_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE); 805 solock(so); 806 } 807 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 808 error = soreserve(so, unpst_sendspace, unpst_recvspace); 809 if (error != 0) 810 return (error); 811 } 812 break; 813 814 case SOCK_DGRAM: 815 if (so->so_lock == NULL) { 816 mutex_obj_hold(uipc_lock); 817 so->so_lock = uipc_lock; 818 solock(so); 819 } 820 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 821 error = soreserve(so, unpdg_sendspace, unpdg_recvspace); 822 if (error != 0) 823 return (error); 824 } 825 break; 826 827 default: 828 panic("unp_attach"); 829 } 830 KASSERT(solocked(so)); 831 unp = malloc(sizeof(*unp), M_PCB, M_NOWAIT); 832 if (unp == NULL) 833 return (ENOBUFS); 834 memset(unp, 0, sizeof(*unp)); 835 unp->unp_socket = so; 836 so->so_pcb = unp; 837 nanotime(&unp->unp_ctime); 838 return (0); 839 } 840 841 void 842 unp_detach(struct unpcb *unp) 843 { 844 struct socket *so; 845 vnode_t *vp; 846 847 so = unp->unp_socket; 848 849 retry: 850 if ((vp = unp->unp_vnode) != NULL) { 851 sounlock(so); 852 /* Acquire v_interlock to protect against unp_connect(). */ 853 /* XXXAD racy */ 854 mutex_enter(vp->v_interlock); 855 vp->v_socket = NULL; 856 vrelel(vp, 0); 857 solock(so); 858 unp->unp_vnode = NULL; 859 } 860 if (unp->unp_conn) 861 unp_disconnect(unp); 862 while (unp->unp_refs) { 863 KASSERT(solocked2(so, unp->unp_refs->unp_socket)); 864 if (unp_drop(unp->unp_refs, ECONNRESET)) { 865 solock(so); 866 goto retry; 867 } 868 } 869 soisdisconnected(so); 870 so->so_pcb = NULL; 871 if (unp_rights) { 872 /* 873 * Normally the receive buffer is flushed later, in sofree, 874 * but if our receive buffer holds references to files that 875 * are now garbage, we will enqueue those file references to 876 * the garbage collector and kick it into action. 877 */ 878 sorflush(so); 879 unp_free(unp); 880 unp_thread_kick(); 881 } else 882 unp_free(unp); 883 } 884 885 /* 886 * Allocate the new sockaddr. We have to allocate one 887 * extra byte so that we can ensure that the pathname 888 * is nul-terminated. Note that unlike linux, we don't 889 * include in the address length the NUL in the path 890 * component, because doing so, would exceed sizeof(sockaddr_un) 891 * for fully occupied pathnames. Linux is also inconsistent, 892 * because it does not include the NUL in the length of 893 * what it calls "abstract" unix sockets. 894 */ 895 static struct sockaddr_un * 896 makeun(struct mbuf *nam, size_t *addrlen) { 897 struct sockaddr_un *sun; 898 899 *addrlen = nam->m_len + 1; 900 sun = malloc(*addrlen, M_SONAME, M_WAITOK); 901 m_copydata(nam, 0, nam->m_len, (void *)sun); 902 *(((char *)sun) + nam->m_len) = '\0'; 903 sun->sun_len = strlen(sun->sun_path) + 904 offsetof(struct sockaddr_un, sun_path); 905 return sun; 906 } 907 908 int 909 unp_bind(struct socket *so, struct mbuf *nam, struct lwp *l) 910 { 911 struct sockaddr_un *sun; 912 struct unpcb *unp; 913 vnode_t *vp; 914 struct vattr vattr; 915 size_t addrlen; 916 int error; 917 struct pathbuf *pb; 918 struct nameidata nd; 919 proc_t *p; 920 921 unp = sotounpcb(so); 922 if (unp->unp_vnode != NULL) 923 return (EINVAL); 924 if ((unp->unp_flags & UNP_BUSY) != 0) { 925 /* 926 * EALREADY may not be strictly accurate, but since this 927 * is a major application error it's hardly a big deal. 928 */ 929 return (EALREADY); 930 } 931 unp->unp_flags |= UNP_BUSY; 932 sounlock(so); 933 934 p = l->l_proc; 935 sun = makeun(nam, &addrlen); 936 937 pb = pathbuf_create(sun->sun_path); 938 if (pb == NULL) { 939 error = ENOMEM; 940 goto bad; 941 } 942 NDINIT(&nd, CREATE, FOLLOW | LOCKPARENT | TRYEMULROOT, pb); 943 944 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 945 if ((error = namei(&nd)) != 0) { 946 pathbuf_destroy(pb); 947 goto bad; 948 } 949 vp = nd.ni_vp; 950 if (vp != NULL) { 951 VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd); 952 if (nd.ni_dvp == vp) 953 vrele(nd.ni_dvp); 954 else 955 vput(nd.ni_dvp); 956 vrele(vp); 957 pathbuf_destroy(pb); 958 error = EADDRINUSE; 959 goto bad; 960 } 961 vattr_null(&vattr); 962 vattr.va_type = VSOCK; 963 vattr.va_mode = ACCESSPERMS & ~(p->p_cwdi->cwdi_cmask); 964 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 965 if (error) { 966 pathbuf_destroy(pb); 967 goto bad; 968 } 969 vp = nd.ni_vp; 970 solock(so); 971 vp->v_socket = unp->unp_socket; 972 unp->unp_vnode = vp; 973 unp->unp_addrlen = addrlen; 974 unp->unp_addr = sun; 975 unp->unp_connid.unp_pid = p->p_pid; 976 unp->unp_connid.unp_euid = kauth_cred_geteuid(l->l_cred); 977 unp->unp_connid.unp_egid = kauth_cred_getegid(l->l_cred); 978 unp->unp_flags |= UNP_EIDSBIND; 979 VOP_UNLOCK(vp); 980 unp->unp_flags &= ~UNP_BUSY; 981 pathbuf_destroy(pb); 982 return (0); 983 984 bad: 985 free(sun, M_SONAME); 986 solock(so); 987 unp->unp_flags &= ~UNP_BUSY; 988 return (error); 989 } 990 991 int 992 unp_connect(struct socket *so, struct mbuf *nam, struct lwp *l) 993 { 994 struct sockaddr_un *sun; 995 vnode_t *vp; 996 struct socket *so2, *so3; 997 struct unpcb *unp, *unp2, *unp3; 998 size_t addrlen; 999 int error; 1000 struct pathbuf *pb; 1001 struct nameidata nd; 1002 1003 unp = sotounpcb(so); 1004 if ((unp->unp_flags & UNP_BUSY) != 0) { 1005 /* 1006 * EALREADY may not be strictly accurate, but since this 1007 * is a major application error it's hardly a big deal. 1008 */ 1009 return (EALREADY); 1010 } 1011 unp->unp_flags |= UNP_BUSY; 1012 sounlock(so); 1013 1014 sun = makeun(nam, &addrlen); 1015 pb = pathbuf_create(sun->sun_path); 1016 if (pb == NULL) { 1017 error = ENOMEM; 1018 goto bad2; 1019 } 1020 1021 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb); 1022 1023 if ((error = namei(&nd)) != 0) { 1024 pathbuf_destroy(pb); 1025 goto bad2; 1026 } 1027 vp = nd.ni_vp; 1028 if (vp->v_type != VSOCK) { 1029 error = ENOTSOCK; 1030 goto bad; 1031 } 1032 pathbuf_destroy(pb); 1033 if ((error = VOP_ACCESS(vp, VWRITE, l->l_cred)) != 0) 1034 goto bad; 1035 /* Acquire v_interlock to protect against unp_detach(). */ 1036 mutex_enter(vp->v_interlock); 1037 so2 = vp->v_socket; 1038 if (so2 == NULL) { 1039 mutex_exit(vp->v_interlock); 1040 error = ECONNREFUSED; 1041 goto bad; 1042 } 1043 if (so->so_type != so2->so_type) { 1044 mutex_exit(vp->v_interlock); 1045 error = EPROTOTYPE; 1046 goto bad; 1047 } 1048 solock(so); 1049 unp_resetlock(so); 1050 mutex_exit(vp->v_interlock); 1051 if ((so->so_proto->pr_flags & PR_CONNREQUIRED) != 0) { 1052 /* 1053 * This may seem somewhat fragile but is OK: if we can 1054 * see SO_ACCEPTCONN set on the endpoint, then it must 1055 * be locked by the domain-wide uipc_lock. 1056 */ 1057 KASSERT((so2->so_options & SO_ACCEPTCONN) == 0 || 1058 so2->so_lock == uipc_lock); 1059 if ((so2->so_options & SO_ACCEPTCONN) == 0 || 1060 (so3 = sonewconn(so2, false)) == NULL) { 1061 error = ECONNREFUSED; 1062 sounlock(so); 1063 goto bad; 1064 } 1065 unp2 = sotounpcb(so2); 1066 unp3 = sotounpcb(so3); 1067 if (unp2->unp_addr) { 1068 unp3->unp_addr = malloc(unp2->unp_addrlen, 1069 M_SONAME, M_WAITOK); 1070 memcpy(unp3->unp_addr, unp2->unp_addr, 1071 unp2->unp_addrlen); 1072 unp3->unp_addrlen = unp2->unp_addrlen; 1073 } 1074 unp3->unp_flags = unp2->unp_flags; 1075 unp3->unp_connid.unp_pid = l->l_proc->p_pid; 1076 unp3->unp_connid.unp_euid = kauth_cred_geteuid(l->l_cred); 1077 unp3->unp_connid.unp_egid = kauth_cred_getegid(l->l_cred); 1078 unp3->unp_flags |= UNP_EIDSVALID; 1079 if (unp2->unp_flags & UNP_EIDSBIND) { 1080 unp->unp_connid = unp2->unp_connid; 1081 unp->unp_flags |= UNP_EIDSVALID; 1082 } 1083 so2 = so3; 1084 } 1085 error = unp_connect2(so, so2, PRU_CONNECT); 1086 sounlock(so); 1087 bad: 1088 vput(vp); 1089 bad2: 1090 free(sun, M_SONAME); 1091 solock(so); 1092 unp->unp_flags &= ~UNP_BUSY; 1093 return (error); 1094 } 1095 1096 int 1097 unp_connect2(struct socket *so, struct socket *so2, int req) 1098 { 1099 struct unpcb *unp = sotounpcb(so); 1100 struct unpcb *unp2; 1101 1102 if (so2->so_type != so->so_type) 1103 return (EPROTOTYPE); 1104 1105 /* 1106 * All three sockets involved must be locked by same lock: 1107 * 1108 * local endpoint (so) 1109 * remote endpoint (so2) 1110 * queue head (so2->so_head, only if PR_CONNREQUIRED) 1111 */ 1112 KASSERT(solocked2(so, so2)); 1113 KASSERT(so->so_head == NULL); 1114 if (so2->so_head != NULL) { 1115 KASSERT(so2->so_lock == uipc_lock); 1116 KASSERT(solocked2(so2, so2->so_head)); 1117 } 1118 1119 unp2 = sotounpcb(so2); 1120 unp->unp_conn = unp2; 1121 switch (so->so_type) { 1122 1123 case SOCK_DGRAM: 1124 unp->unp_nextref = unp2->unp_refs; 1125 unp2->unp_refs = unp; 1126 soisconnected(so); 1127 break; 1128 1129 case SOCK_SEQPACKET: /* FALLTHROUGH */ 1130 case SOCK_STREAM: 1131 unp2->unp_conn = unp; 1132 if (req == PRU_CONNECT && 1133 ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT)) 1134 soisconnecting(so); 1135 else 1136 soisconnected(so); 1137 soisconnected(so2); 1138 /* 1139 * If the connection is fully established, break the 1140 * association with uipc_lock and give the connected 1141 * pair a seperate lock to share. For CONNECT2, we 1142 * require that the locks already match (the sockets 1143 * are created that way). 1144 */ 1145 if (req == PRU_CONNECT) { 1146 KASSERT(so2->so_head != NULL); 1147 unp_setpeerlocks(so, so2); 1148 } 1149 break; 1150 1151 default: 1152 panic("unp_connect2"); 1153 } 1154 return (0); 1155 } 1156 1157 void 1158 unp_disconnect(struct unpcb *unp) 1159 { 1160 struct unpcb *unp2 = unp->unp_conn; 1161 struct socket *so; 1162 1163 if (unp2 == 0) 1164 return; 1165 unp->unp_conn = 0; 1166 so = unp->unp_socket; 1167 switch (so->so_type) { 1168 case SOCK_DGRAM: 1169 if (unp2->unp_refs == unp) 1170 unp2->unp_refs = unp->unp_nextref; 1171 else { 1172 unp2 = unp2->unp_refs; 1173 for (;;) { 1174 KASSERT(solocked2(so, unp2->unp_socket)); 1175 if (unp2 == 0) 1176 panic("unp_disconnect"); 1177 if (unp2->unp_nextref == unp) 1178 break; 1179 unp2 = unp2->unp_nextref; 1180 } 1181 unp2->unp_nextref = unp->unp_nextref; 1182 } 1183 unp->unp_nextref = 0; 1184 so->so_state &= ~SS_ISCONNECTED; 1185 break; 1186 1187 case SOCK_SEQPACKET: /* FALLTHROUGH */ 1188 case SOCK_STREAM: 1189 KASSERT(solocked2(so, unp2->unp_socket)); 1190 soisdisconnected(so); 1191 unp2->unp_conn = 0; 1192 soisdisconnected(unp2->unp_socket); 1193 break; 1194 } 1195 } 1196 1197 #ifdef notdef 1198 unp_abort(struct unpcb *unp) 1199 { 1200 unp_detach(unp); 1201 } 1202 #endif 1203 1204 void 1205 unp_shutdown(struct unpcb *unp) 1206 { 1207 struct socket *so; 1208 1209 switch(unp->unp_socket->so_type) { 1210 case SOCK_SEQPACKET: /* FALLTHROUGH */ 1211 case SOCK_STREAM: 1212 if (unp->unp_conn && (so = unp->unp_conn->unp_socket)) 1213 socantrcvmore(so); 1214 break; 1215 default: 1216 break; 1217 } 1218 } 1219 1220 bool 1221 unp_drop(struct unpcb *unp, int errno) 1222 { 1223 struct socket *so = unp->unp_socket; 1224 1225 KASSERT(solocked(so)); 1226 1227 so->so_error = errno; 1228 unp_disconnect(unp); 1229 if (so->so_head) { 1230 so->so_pcb = NULL; 1231 /* sofree() drops the socket lock */ 1232 sofree(so); 1233 unp_free(unp); 1234 return true; 1235 } 1236 return false; 1237 } 1238 1239 #ifdef notdef 1240 unp_drain(void) 1241 { 1242 1243 } 1244 #endif 1245 1246 int 1247 unp_externalize(struct mbuf *rights, struct lwp *l, int flags) 1248 { 1249 struct cmsghdr * const cm = mtod(rights, struct cmsghdr *); 1250 struct proc * const p = l->l_proc; 1251 file_t **rp; 1252 int error = 0; 1253 1254 const size_t nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) / 1255 sizeof(file_t *); 1256 if (nfds == 0) 1257 goto noop; 1258 1259 int * const fdp = kmem_alloc(nfds * sizeof(int), KM_SLEEP); 1260 rw_enter(&p->p_cwdi->cwdi_lock, RW_READER); 1261 1262 /* Make sure the recipient should be able to see the files.. */ 1263 rp = (file_t **)CMSG_DATA(cm); 1264 for (size_t i = 0; i < nfds; i++) { 1265 file_t * const fp = *rp++; 1266 if (fp == NULL) { 1267 error = EINVAL; 1268 goto out; 1269 } 1270 /* 1271 * If we are in a chroot'ed directory, and 1272 * someone wants to pass us a directory, make 1273 * sure it's inside the subtree we're allowed 1274 * to access. 1275 */ 1276 if (p->p_cwdi->cwdi_rdir != NULL && fp->f_type == DTYPE_VNODE) { 1277 vnode_t *vp = (vnode_t *)fp->f_data; 1278 if ((vp->v_type == VDIR) && 1279 !vn_isunder(vp, p->p_cwdi->cwdi_rdir, l)) { 1280 error = EPERM; 1281 goto out; 1282 } 1283 } 1284 } 1285 1286 restart: 1287 /* 1288 * First loop -- allocate file descriptor table slots for the 1289 * new files. 1290 */ 1291 for (size_t i = 0; i < nfds; i++) { 1292 if ((error = fd_alloc(p, 0, &fdp[i])) != 0) { 1293 /* 1294 * Back out what we've done so far. 1295 */ 1296 while (i-- > 0) { 1297 fd_abort(p, NULL, fdp[i]); 1298 } 1299 if (error == ENOSPC) { 1300 fd_tryexpand(p); 1301 error = 0; 1302 goto restart; 1303 } 1304 /* 1305 * This is the error that has historically 1306 * been returned, and some callers may 1307 * expect it. 1308 */ 1309 error = EMSGSIZE; 1310 goto out; 1311 } 1312 } 1313 1314 /* 1315 * Now that adding them has succeeded, update all of the 1316 * file passing state and affix the descriptors. 1317 */ 1318 rp = (file_t **)CMSG_DATA(cm); 1319 int *ofdp = (int *)CMSG_DATA(cm); 1320 for (size_t i = 0; i < nfds; i++) { 1321 file_t * const fp = *rp++; 1322 const int fd = fdp[i]; 1323 atomic_dec_uint(&unp_rights); 1324 fd_set_exclose(l, fd, (flags & O_CLOEXEC) != 0); 1325 fd_affix(p, fp, fd); 1326 /* 1327 * Done with this file pointer, replace it with a fd; 1328 */ 1329 *ofdp++ = fd; 1330 mutex_enter(&fp->f_lock); 1331 fp->f_msgcount--; 1332 mutex_exit(&fp->f_lock); 1333 /* 1334 * Note that fd_affix() adds a reference to the file. 1335 * The file may already have been closed by another 1336 * LWP in the process, so we must drop the reference 1337 * added by unp_internalize() with closef(). 1338 */ 1339 closef(fp); 1340 } 1341 1342 /* 1343 * Adjust length, in case of transition from large file_t 1344 * pointers to ints. 1345 */ 1346 if (sizeof(file_t *) != sizeof(int)) { 1347 cm->cmsg_len = CMSG_LEN(nfds * sizeof(int)); 1348 rights->m_len = CMSG_SPACE(nfds * sizeof(int)); 1349 } 1350 out: 1351 if (__predict_false(error != 0)) { 1352 file_t **const fpp = (file_t **)CMSG_DATA(cm); 1353 for (size_t i = 0; i < nfds; i++) 1354 unp_discard_now(fpp[i]); 1355 /* 1356 * Truncate the array so that nobody will try to interpret 1357 * what is now garbage in it. 1358 */ 1359 cm->cmsg_len = CMSG_LEN(0); 1360 rights->m_len = CMSG_SPACE(0); 1361 } 1362 rw_exit(&p->p_cwdi->cwdi_lock); 1363 kmem_free(fdp, nfds * sizeof(int)); 1364 1365 noop: 1366 /* 1367 * Don't disclose kernel memory in the alignment space. 1368 */ 1369 KASSERT(cm->cmsg_len <= rights->m_len); 1370 memset(&mtod(rights, char *)[cm->cmsg_len], 0, rights->m_len - 1371 cm->cmsg_len); 1372 return error; 1373 } 1374 1375 int 1376 unp_internalize(struct mbuf **controlp) 1377 { 1378 filedesc_t *fdescp = curlwp->l_fd; 1379 struct mbuf *control = *controlp; 1380 struct cmsghdr *newcm, *cm = mtod(control, struct cmsghdr *); 1381 file_t **rp, **files; 1382 file_t *fp; 1383 int i, fd, *fdp; 1384 int nfds, error; 1385 u_int maxmsg; 1386 1387 error = 0; 1388 newcm = NULL; 1389 1390 /* Sanity check the control message header. */ 1391 if (cm->cmsg_type != SCM_RIGHTS || cm->cmsg_level != SOL_SOCKET || 1392 cm->cmsg_len > control->m_len || 1393 cm->cmsg_len < CMSG_ALIGN(sizeof(*cm))) 1394 return (EINVAL); 1395 1396 /* 1397 * Verify that the file descriptors are valid, and acquire 1398 * a reference to each. 1399 */ 1400 nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) / sizeof(int); 1401 fdp = (int *)CMSG_DATA(cm); 1402 maxmsg = maxfiles / unp_rights_ratio; 1403 for (i = 0; i < nfds; i++) { 1404 fd = *fdp++; 1405 if (atomic_inc_uint_nv(&unp_rights) > maxmsg) { 1406 atomic_dec_uint(&unp_rights); 1407 nfds = i; 1408 error = EAGAIN; 1409 goto out; 1410 } 1411 if ((fp = fd_getfile(fd)) == NULL 1412 || fp->f_type == DTYPE_KQUEUE) { 1413 if (fp) 1414 fd_putfile(fd); 1415 atomic_dec_uint(&unp_rights); 1416 nfds = i; 1417 error = EBADF; 1418 goto out; 1419 } 1420 } 1421 1422 /* Allocate new space and copy header into it. */ 1423 newcm = malloc(CMSG_SPACE(nfds * sizeof(file_t *)), M_MBUF, M_WAITOK); 1424 if (newcm == NULL) { 1425 error = E2BIG; 1426 goto out; 1427 } 1428 memcpy(newcm, cm, sizeof(struct cmsghdr)); 1429 files = (file_t **)CMSG_DATA(newcm); 1430 1431 /* 1432 * Transform the file descriptors into file_t pointers, in 1433 * reverse order so that if pointers are bigger than ints, the 1434 * int won't get until we're done. No need to lock, as we have 1435 * already validated the descriptors with fd_getfile(). 1436 */ 1437 fdp = (int *)CMSG_DATA(cm) + nfds; 1438 rp = files + nfds; 1439 for (i = 0; i < nfds; i++) { 1440 fp = fdescp->fd_dt->dt_ff[*--fdp]->ff_file; 1441 KASSERT(fp != NULL); 1442 mutex_enter(&fp->f_lock); 1443 *--rp = fp; 1444 fp->f_count++; 1445 fp->f_msgcount++; 1446 mutex_exit(&fp->f_lock); 1447 } 1448 1449 out: 1450 /* Release descriptor references. */ 1451 fdp = (int *)CMSG_DATA(cm); 1452 for (i = 0; i < nfds; i++) { 1453 fd_putfile(*fdp++); 1454 if (error != 0) { 1455 atomic_dec_uint(&unp_rights); 1456 } 1457 } 1458 1459 if (error == 0) { 1460 if (control->m_flags & M_EXT) { 1461 m_freem(control); 1462 *controlp = control = m_get(M_WAIT, MT_CONTROL); 1463 } 1464 MEXTADD(control, newcm, CMSG_SPACE(nfds * sizeof(file_t *)), 1465 M_MBUF, NULL, NULL); 1466 cm = newcm; 1467 /* 1468 * Adjust message & mbuf to note amount of space 1469 * actually used. 1470 */ 1471 cm->cmsg_len = CMSG_LEN(nfds * sizeof(file_t *)); 1472 control->m_len = CMSG_SPACE(nfds * sizeof(file_t *)); 1473 } 1474 1475 return error; 1476 } 1477 1478 struct mbuf * 1479 unp_addsockcred(struct lwp *l, struct mbuf *control) 1480 { 1481 struct sockcred *sc; 1482 struct mbuf *m; 1483 void *p; 1484 1485 m = sbcreatecontrol1(&p, SOCKCREDSIZE(kauth_cred_ngroups(l->l_cred)), 1486 SCM_CREDS, SOL_SOCKET, M_WAITOK); 1487 if (m == NULL) 1488 return control; 1489 1490 sc = p; 1491 sc->sc_uid = kauth_cred_getuid(l->l_cred); 1492 sc->sc_euid = kauth_cred_geteuid(l->l_cred); 1493 sc->sc_gid = kauth_cred_getgid(l->l_cred); 1494 sc->sc_egid = kauth_cred_getegid(l->l_cred); 1495 sc->sc_ngroups = kauth_cred_ngroups(l->l_cred); 1496 1497 for (int i = 0; i < sc->sc_ngroups; i++) 1498 sc->sc_groups[i] = kauth_cred_group(l->l_cred, i); 1499 1500 return m_add(control, m); 1501 } 1502 1503 /* 1504 * Do a mark-sweep GC of files in the system, to free up any which are 1505 * caught in flight to an about-to-be-closed socket. Additionally, 1506 * process deferred file closures. 1507 */ 1508 static void 1509 unp_gc(file_t *dp) 1510 { 1511 extern struct domain unixdomain; 1512 file_t *fp, *np; 1513 struct socket *so, *so1; 1514 u_int i, old, new; 1515 bool didwork; 1516 1517 KASSERT(curlwp == unp_thread_lwp); 1518 KASSERT(mutex_owned(&filelist_lock)); 1519 1520 /* 1521 * First, process deferred file closures. 1522 */ 1523 while (!SLIST_EMPTY(&unp_thread_discard)) { 1524 fp = SLIST_FIRST(&unp_thread_discard); 1525 KASSERT(fp->f_unpcount > 0); 1526 KASSERT(fp->f_count > 0); 1527 KASSERT(fp->f_msgcount > 0); 1528 KASSERT(fp->f_count >= fp->f_unpcount); 1529 KASSERT(fp->f_count >= fp->f_msgcount); 1530 KASSERT(fp->f_msgcount >= fp->f_unpcount); 1531 SLIST_REMOVE_HEAD(&unp_thread_discard, f_unplist); 1532 i = fp->f_unpcount; 1533 fp->f_unpcount = 0; 1534 mutex_exit(&filelist_lock); 1535 for (; i != 0; i--) { 1536 unp_discard_now(fp); 1537 } 1538 mutex_enter(&filelist_lock); 1539 } 1540 1541 /* 1542 * Clear mark bits. Ensure that we don't consider new files 1543 * entering the file table during this loop (they will not have 1544 * FSCAN set). 1545 */ 1546 unp_defer = 0; 1547 LIST_FOREACH(fp, &filehead, f_list) { 1548 for (old = fp->f_flag;; old = new) { 1549 new = atomic_cas_uint(&fp->f_flag, old, 1550 (old | FSCAN) & ~(FMARK|FDEFER)); 1551 if (__predict_true(old == new)) { 1552 break; 1553 } 1554 } 1555 } 1556 1557 /* 1558 * Iterate over the set of sockets, marking ones believed (based on 1559 * refcount) to be referenced from a process, and marking for rescan 1560 * sockets which are queued on a socket. Recan continues descending 1561 * and searching for sockets referenced by sockets (FDEFER), until 1562 * there are no more socket->socket references to be discovered. 1563 */ 1564 do { 1565 didwork = false; 1566 for (fp = LIST_FIRST(&filehead); fp != NULL; fp = np) { 1567 KASSERT(mutex_owned(&filelist_lock)); 1568 np = LIST_NEXT(fp, f_list); 1569 mutex_enter(&fp->f_lock); 1570 if ((fp->f_flag & FDEFER) != 0) { 1571 atomic_and_uint(&fp->f_flag, ~FDEFER); 1572 unp_defer--; 1573 KASSERT(fp->f_count != 0); 1574 } else { 1575 if (fp->f_count == 0 || 1576 (fp->f_flag & FMARK) != 0 || 1577 fp->f_count == fp->f_msgcount || 1578 fp->f_unpcount != 0) { 1579 mutex_exit(&fp->f_lock); 1580 continue; 1581 } 1582 } 1583 atomic_or_uint(&fp->f_flag, FMARK); 1584 1585 if (fp->f_type != DTYPE_SOCKET || 1586 (so = fp->f_data) == NULL || 1587 so->so_proto->pr_domain != &unixdomain || 1588 (so->so_proto->pr_flags & PR_RIGHTS) == 0) { 1589 mutex_exit(&fp->f_lock); 1590 continue; 1591 } 1592 1593 /* Gain file ref, mark our position, and unlock. */ 1594 didwork = true; 1595 LIST_INSERT_AFTER(fp, dp, f_list); 1596 fp->f_count++; 1597 mutex_exit(&fp->f_lock); 1598 mutex_exit(&filelist_lock); 1599 1600 /* 1601 * Mark files referenced from sockets queued on the 1602 * accept queue as well. 1603 */ 1604 solock(so); 1605 unp_scan(so->so_rcv.sb_mb, unp_mark, 0); 1606 if ((so->so_options & SO_ACCEPTCONN) != 0) { 1607 TAILQ_FOREACH(so1, &so->so_q0, so_qe) { 1608 unp_scan(so1->so_rcv.sb_mb, unp_mark, 0); 1609 } 1610 TAILQ_FOREACH(so1, &so->so_q, so_qe) { 1611 unp_scan(so1->so_rcv.sb_mb, unp_mark, 0); 1612 } 1613 } 1614 sounlock(so); 1615 1616 /* Re-lock and restart from where we left off. */ 1617 closef(fp); 1618 mutex_enter(&filelist_lock); 1619 np = LIST_NEXT(dp, f_list); 1620 LIST_REMOVE(dp, f_list); 1621 } 1622 /* 1623 * Bail early if we did nothing in the loop above. Could 1624 * happen because of concurrent activity causing unp_defer 1625 * to get out of sync. 1626 */ 1627 } while (unp_defer != 0 && didwork); 1628 1629 /* 1630 * Sweep pass. 1631 * 1632 * We grab an extra reference to each of the files that are 1633 * not otherwise accessible and then free the rights that are 1634 * stored in messages on them. 1635 */ 1636 for (fp = LIST_FIRST(&filehead); fp != NULL; fp = np) { 1637 KASSERT(mutex_owned(&filelist_lock)); 1638 np = LIST_NEXT(fp, f_list); 1639 mutex_enter(&fp->f_lock); 1640 1641 /* 1642 * Ignore non-sockets. 1643 * Ignore dead sockets, or sockets with pending close. 1644 * Ignore sockets obviously referenced elsewhere. 1645 * Ignore sockets marked as referenced by our scan. 1646 * Ignore new sockets that did not exist during the scan. 1647 */ 1648 if (fp->f_type != DTYPE_SOCKET || 1649 fp->f_count == 0 || fp->f_unpcount != 0 || 1650 fp->f_count != fp->f_msgcount || 1651 (fp->f_flag & (FMARK | FSCAN)) != FSCAN) { 1652 mutex_exit(&fp->f_lock); 1653 continue; 1654 } 1655 1656 /* Gain file ref, mark our position, and unlock. */ 1657 LIST_INSERT_AFTER(fp, dp, f_list); 1658 fp->f_count++; 1659 mutex_exit(&fp->f_lock); 1660 mutex_exit(&filelist_lock); 1661 1662 /* 1663 * Flush all data from the socket's receive buffer. 1664 * This will cause files referenced only by the 1665 * socket to be queued for close. 1666 */ 1667 so = fp->f_data; 1668 solock(so); 1669 sorflush(so); 1670 sounlock(so); 1671 1672 /* Re-lock and restart from where we left off. */ 1673 closef(fp); 1674 mutex_enter(&filelist_lock); 1675 np = LIST_NEXT(dp, f_list); 1676 LIST_REMOVE(dp, f_list); 1677 } 1678 } 1679 1680 /* 1681 * Garbage collector thread. While SCM_RIGHTS messages are in transit, 1682 * wake once per second to garbage collect. Run continually while we 1683 * have deferred closes to process. 1684 */ 1685 static void 1686 unp_thread(void *cookie) 1687 { 1688 file_t *dp; 1689 1690 /* Allocate a dummy file for our scans. */ 1691 if ((dp = fgetdummy()) == NULL) { 1692 panic("unp_thread"); 1693 } 1694 1695 mutex_enter(&filelist_lock); 1696 for (;;) { 1697 KASSERT(mutex_owned(&filelist_lock)); 1698 if (SLIST_EMPTY(&unp_thread_discard)) { 1699 if (unp_rights != 0) { 1700 (void)cv_timedwait(&unp_thread_cv, 1701 &filelist_lock, hz); 1702 } else { 1703 cv_wait(&unp_thread_cv, &filelist_lock); 1704 } 1705 } 1706 unp_gc(dp); 1707 } 1708 /* NOTREACHED */ 1709 } 1710 1711 /* 1712 * Kick the garbage collector into action if there is something for 1713 * it to process. 1714 */ 1715 static void 1716 unp_thread_kick(void) 1717 { 1718 1719 if (!SLIST_EMPTY(&unp_thread_discard) || unp_rights != 0) { 1720 mutex_enter(&filelist_lock); 1721 cv_signal(&unp_thread_cv); 1722 mutex_exit(&filelist_lock); 1723 } 1724 } 1725 1726 void 1727 unp_dispose(struct mbuf *m) 1728 { 1729 1730 if (m) 1731 unp_scan(m, unp_discard_later, 1); 1732 } 1733 1734 void 1735 unp_scan(struct mbuf *m0, void (*op)(file_t *), int discard) 1736 { 1737 struct mbuf *m; 1738 file_t **rp, *fp; 1739 struct cmsghdr *cm; 1740 int i, qfds; 1741 1742 while (m0) { 1743 for (m = m0; m; m = m->m_next) { 1744 if (m->m_type != MT_CONTROL || 1745 m->m_len < sizeof(*cm)) { 1746 continue; 1747 } 1748 cm = mtod(m, struct cmsghdr *); 1749 if (cm->cmsg_level != SOL_SOCKET || 1750 cm->cmsg_type != SCM_RIGHTS) 1751 continue; 1752 qfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) 1753 / sizeof(file_t *); 1754 rp = (file_t **)CMSG_DATA(cm); 1755 for (i = 0; i < qfds; i++) { 1756 fp = *rp; 1757 if (discard) { 1758 *rp = 0; 1759 } 1760 (*op)(fp); 1761 rp++; 1762 } 1763 } 1764 m0 = m0->m_nextpkt; 1765 } 1766 } 1767 1768 void 1769 unp_mark(file_t *fp) 1770 { 1771 1772 if (fp == NULL) 1773 return; 1774 1775 /* If we're already deferred, don't screw up the defer count */ 1776 mutex_enter(&fp->f_lock); 1777 if (fp->f_flag & (FMARK | FDEFER)) { 1778 mutex_exit(&fp->f_lock); 1779 return; 1780 } 1781 1782 /* 1783 * Minimize the number of deferrals... Sockets are the only type of 1784 * file which can hold references to another file, so just mark 1785 * other files, and defer unmarked sockets for the next pass. 1786 */ 1787 if (fp->f_type == DTYPE_SOCKET) { 1788 unp_defer++; 1789 KASSERT(fp->f_count != 0); 1790 atomic_or_uint(&fp->f_flag, FDEFER); 1791 } else { 1792 atomic_or_uint(&fp->f_flag, FMARK); 1793 } 1794 mutex_exit(&fp->f_lock); 1795 } 1796 1797 static void 1798 unp_discard_now(file_t *fp) 1799 { 1800 1801 if (fp == NULL) 1802 return; 1803 1804 KASSERT(fp->f_count > 0); 1805 KASSERT(fp->f_msgcount > 0); 1806 1807 mutex_enter(&fp->f_lock); 1808 fp->f_msgcount--; 1809 mutex_exit(&fp->f_lock); 1810 atomic_dec_uint(&unp_rights); 1811 (void)closef(fp); 1812 } 1813 1814 static void 1815 unp_discard_later(file_t *fp) 1816 { 1817 1818 if (fp == NULL) 1819 return; 1820 1821 KASSERT(fp->f_count > 0); 1822 KASSERT(fp->f_msgcount > 0); 1823 1824 mutex_enter(&filelist_lock); 1825 if (fp->f_unpcount++ == 0) { 1826 SLIST_INSERT_HEAD(&unp_thread_discard, fp, f_unplist); 1827 } 1828 mutex_exit(&filelist_lock); 1829 } 1830