uipc_usrreq.c revision 1.174
1 /* $NetBSD: uipc_usrreq.c,v 1.174 2015/02/28 21:42:01 rtr 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 1.174 2015/02/28 21:42:01 rtr 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 static struct mbuf * unp_addsockcred(struct lwp *, struct mbuf *); 174 static void unp_discard_later(file_t *); 175 static void unp_discard_now(file_t *); 176 static void unp_disconnect1(struct unpcb *); 177 static bool unp_drop(struct unpcb *, int); 178 static int unp_internalize(struct mbuf **); 179 static void unp_mark(file_t *); 180 static void unp_scan(struct mbuf *, void (*)(file_t *), int); 181 static void unp_shutdown1(struct unpcb *); 182 static void unp_thread(void *); 183 static void unp_thread_kick(void); 184 185 static kmutex_t *uipc_lock; 186 187 static kcondvar_t unp_thread_cv; 188 static lwp_t *unp_thread_lwp; 189 static SLIST_HEAD(,file) unp_thread_discard; 190 static int unp_defer; 191 192 /* 193 * Initialize Unix protocols. 194 */ 195 void 196 uipc_init(void) 197 { 198 int error; 199 200 uipc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE); 201 cv_init(&unp_thread_cv, "unpgc"); 202 203 error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL, unp_thread, 204 NULL, &unp_thread_lwp, "unpgc"); 205 if (error != 0) 206 panic("uipc_init %d", error); 207 } 208 209 /* 210 * A connection succeeded: disassociate both endpoints from the head's 211 * lock, and make them share their own lock. There is a race here: for 212 * a very brief time one endpoint will be locked by a different lock 213 * than the other end. However, since the current thread holds the old 214 * lock (the listening socket's lock, the head) access can still only be 215 * made to one side of the connection. 216 */ 217 static void 218 unp_setpeerlocks(struct socket *so, struct socket *so2) 219 { 220 struct unpcb *unp; 221 kmutex_t *lock; 222 223 KASSERT(solocked2(so, so2)); 224 225 /* 226 * Bail out if either end of the socket is not yet fully 227 * connected or accepted. We only break the lock association 228 * with the head when the pair of sockets stand completely 229 * on their own. 230 */ 231 KASSERT(so->so_head == NULL); 232 if (so2->so_head != NULL) 233 return; 234 235 /* 236 * Drop references to old lock. A third reference (from the 237 * queue head) must be held as we still hold its lock. Bonus: 238 * we don't need to worry about garbage collecting the lock. 239 */ 240 lock = so->so_lock; 241 KASSERT(lock == uipc_lock); 242 mutex_obj_free(lock); 243 mutex_obj_free(lock); 244 245 /* 246 * Grab stream lock from the initiator and share between the two 247 * endpoints. Issue memory barrier to ensure all modifications 248 * become globally visible before the lock change. so2 is 249 * assumed not to have a stream lock, because it was created 250 * purely for the server side to accept this connection and 251 * started out life using the domain-wide lock. 252 */ 253 unp = sotounpcb(so); 254 KASSERT(unp->unp_streamlock != NULL); 255 KASSERT(sotounpcb(so2)->unp_streamlock == NULL); 256 lock = unp->unp_streamlock; 257 unp->unp_streamlock = NULL; 258 mutex_obj_hold(lock); 259 membar_exit(); 260 /* 261 * possible race if lock is not held - see comment in 262 * uipc_usrreq(PRU_ACCEPT). 263 */ 264 KASSERT(mutex_owned(lock)); 265 solockreset(so, lock); 266 solockreset(so2, lock); 267 } 268 269 /* 270 * Reset a socket's lock back to the domain-wide lock. 271 */ 272 static void 273 unp_resetlock(struct socket *so) 274 { 275 kmutex_t *olock, *nlock; 276 struct unpcb *unp; 277 278 KASSERT(solocked(so)); 279 280 olock = so->so_lock; 281 nlock = uipc_lock; 282 if (olock == nlock) 283 return; 284 unp = sotounpcb(so); 285 KASSERT(unp->unp_streamlock == NULL); 286 unp->unp_streamlock = olock; 287 mutex_obj_hold(nlock); 288 mutex_enter(nlock); 289 solockreset(so, nlock); 290 mutex_exit(olock); 291 } 292 293 static void 294 unp_free(struct unpcb *unp) 295 { 296 if (unp->unp_addr) 297 free(unp->unp_addr, M_SONAME); 298 if (unp->unp_streamlock != NULL) 299 mutex_obj_free(unp->unp_streamlock); 300 kmem_free(unp, sizeof(*unp)); 301 } 302 303 static int 304 unp_output(struct mbuf *m, struct mbuf *control, struct unpcb *unp) 305 { 306 struct socket *so2; 307 const struct sockaddr_un *sun; 308 309 /* XXX: server side closed the socket */ 310 if (unp->unp_conn == NULL) 311 return ECONNREFUSED; 312 so2 = unp->unp_conn->unp_socket; 313 314 KASSERT(solocked(so2)); 315 316 if (unp->unp_addr) 317 sun = unp->unp_addr; 318 else 319 sun = &sun_noname; 320 if (unp->unp_conn->unp_flags & UNP_WANTCRED) 321 control = unp_addsockcred(curlwp, control); 322 if (sbappendaddr(&so2->so_rcv, (const struct sockaddr *)sun, m, 323 control) == 0) { 324 so2->so_rcv.sb_overflowed++; 325 unp_dispose(control); 326 m_freem(control); 327 m_freem(m); 328 return (ENOBUFS); 329 } else { 330 sorwakeup(so2); 331 return (0); 332 } 333 } 334 335 static void 336 unp_setaddr(struct socket *so, struct mbuf *nam, bool peeraddr) 337 { 338 const struct sockaddr_un *sun; 339 struct unpcb *unp; 340 bool ext; 341 342 KASSERT(solocked(so)); 343 unp = sotounpcb(so); 344 ext = false; 345 346 for (;;) { 347 sun = NULL; 348 if (peeraddr) { 349 if (unp->unp_conn && unp->unp_conn->unp_addr) 350 sun = unp->unp_conn->unp_addr; 351 } else { 352 if (unp->unp_addr) 353 sun = unp->unp_addr; 354 } 355 if (sun == NULL) 356 sun = &sun_noname; 357 nam->m_len = sun->sun_len; 358 if (nam->m_len > MLEN && !ext) { 359 sounlock(so); 360 MEXTMALLOC(nam, MAXPATHLEN * 2, M_WAITOK); 361 solock(so); 362 ext = true; 363 } else { 364 KASSERT(nam->m_len <= MAXPATHLEN * 2); 365 memcpy(mtod(nam, void *), sun, (size_t)nam->m_len); 366 break; 367 } 368 } 369 } 370 371 static int 372 unp_rcvd(struct socket *so, int flags, struct lwp *l) 373 { 374 struct unpcb *unp = sotounpcb(so); 375 struct socket *so2; 376 u_int newhiwat; 377 378 KASSERT(solocked(so)); 379 KASSERT(unp != NULL); 380 381 switch (so->so_type) { 382 383 case SOCK_DGRAM: 384 panic("uipc 1"); 385 /*NOTREACHED*/ 386 387 case SOCK_SEQPACKET: /* FALLTHROUGH */ 388 case SOCK_STREAM: 389 #define rcv (&so->so_rcv) 390 #define snd (&so2->so_snd) 391 if (unp->unp_conn == 0) 392 break; 393 so2 = unp->unp_conn->unp_socket; 394 KASSERT(solocked2(so, so2)); 395 /* 396 * Adjust backpressure on sender 397 * and wakeup any waiting to write. 398 */ 399 snd->sb_mbmax += unp->unp_mbcnt - rcv->sb_mbcnt; 400 unp->unp_mbcnt = rcv->sb_mbcnt; 401 newhiwat = snd->sb_hiwat + unp->unp_cc - rcv->sb_cc; 402 (void)chgsbsize(so2->so_uidinfo, 403 &snd->sb_hiwat, newhiwat, RLIM_INFINITY); 404 unp->unp_cc = rcv->sb_cc; 405 sowwakeup(so2); 406 #undef snd 407 #undef rcv 408 break; 409 410 default: 411 panic("uipc 2"); 412 } 413 414 return 0; 415 } 416 417 static int 418 unp_recvoob(struct socket *so, struct mbuf *m, int flags) 419 { 420 KASSERT(solocked(so)); 421 422 return EOPNOTSUPP; 423 } 424 425 static int 426 unp_send(struct socket *so, struct mbuf *m, struct mbuf *nam, 427 struct mbuf *control, struct lwp *l) 428 { 429 struct unpcb *unp = sotounpcb(so); 430 int error = 0; 431 u_int newhiwat; 432 struct socket *so2; 433 434 KASSERT(solocked(so)); 435 KASSERT(unp != NULL); 436 KASSERT(m != NULL); 437 438 /* 439 * Note: unp_internalize() rejects any control message 440 * other than SCM_RIGHTS, and only allows one. This 441 * has the side-effect of preventing a caller from 442 * forging SCM_CREDS. 443 */ 444 if (control) { 445 sounlock(so); 446 error = unp_internalize(&control); 447 solock(so); 448 if (error != 0) { 449 m_freem(control); 450 m_freem(m); 451 return error; 452 } 453 } 454 455 switch (so->so_type) { 456 457 case SOCK_DGRAM: { 458 KASSERT(so->so_lock == uipc_lock); 459 if (nam) { 460 if ((so->so_state & SS_ISCONNECTED) != 0) 461 error = EISCONN; 462 else { 463 /* 464 * Note: once connected, the 465 * socket's lock must not be 466 * dropped until we have sent 467 * the message and disconnected. 468 * This is necessary to prevent 469 * intervening control ops, like 470 * another connection. 471 */ 472 error = unp_connect(so, nam, l); 473 } 474 } else { 475 if ((so->so_state & SS_ISCONNECTED) == 0) 476 error = ENOTCONN; 477 } 478 if (error) { 479 unp_dispose(control); 480 m_freem(control); 481 m_freem(m); 482 return error; 483 } 484 error = unp_output(m, control, unp); 485 if (nam) 486 unp_disconnect1(unp); 487 break; 488 } 489 490 case SOCK_SEQPACKET: /* FALLTHROUGH */ 491 case SOCK_STREAM: 492 #define rcv (&so2->so_rcv) 493 #define snd (&so->so_snd) 494 if (unp->unp_conn == NULL) { 495 error = ENOTCONN; 496 break; 497 } 498 so2 = unp->unp_conn->unp_socket; 499 KASSERT(solocked2(so, so2)); 500 if (unp->unp_conn->unp_flags & UNP_WANTCRED) { 501 /* 502 * Credentials are passed only once on 503 * SOCK_STREAM and SOCK_SEQPACKET. 504 */ 505 unp->unp_conn->unp_flags &= ~UNP_WANTCRED; 506 control = unp_addsockcred(l, control); 507 } 508 /* 509 * Send to paired receive port, and then reduce 510 * send buffer hiwater marks to maintain backpressure. 511 * Wake up readers. 512 */ 513 if (control) { 514 if (sbappendcontrol(rcv, m, control) != 0) 515 control = NULL; 516 } else { 517 switch(so->so_type) { 518 case SOCK_SEQPACKET: 519 sbappendrecord(rcv, m); 520 break; 521 case SOCK_STREAM: 522 sbappend(rcv, m); 523 break; 524 default: 525 panic("uipc_usrreq"); 526 break; 527 } 528 } 529 snd->sb_mbmax -= 530 rcv->sb_mbcnt - unp->unp_conn->unp_mbcnt; 531 unp->unp_conn->unp_mbcnt = rcv->sb_mbcnt; 532 newhiwat = snd->sb_hiwat - 533 (rcv->sb_cc - unp->unp_conn->unp_cc); 534 (void)chgsbsize(so->so_uidinfo, 535 &snd->sb_hiwat, newhiwat, RLIM_INFINITY); 536 unp->unp_conn->unp_cc = rcv->sb_cc; 537 sorwakeup(so2); 538 #undef snd 539 #undef rcv 540 if (control != NULL) { 541 unp_dispose(control); 542 m_freem(control); 543 } 544 break; 545 546 default: 547 panic("uipc 4"); 548 } 549 550 return error; 551 } 552 553 static int 554 unp_sendoob(struct socket *so, struct mbuf *m, struct mbuf * control) 555 { 556 KASSERT(solocked(so)); 557 558 m_freem(m); 559 m_freem(control); 560 561 return EOPNOTSUPP; 562 } 563 564 static int 565 unp_usrreq(struct socket *so, int req, struct mbuf *m, struct mbuf *nam, 566 struct mbuf *control, struct lwp *l) 567 { 568 569 KASSERT(req != PRU_ATTACH); 570 KASSERT(req != PRU_DETACH); 571 KASSERT(req != PRU_ACCEPT); 572 KASSERT(req != PRU_BIND); 573 KASSERT(req != PRU_LISTEN); 574 KASSERT(req != PRU_CONNECT); 575 KASSERT(req != PRU_CONNECT2); 576 KASSERT(req != PRU_DISCONNECT); 577 KASSERT(req != PRU_SHUTDOWN); 578 KASSERT(req != PRU_ABORT); 579 KASSERT(req != PRU_CONTROL); 580 KASSERT(req != PRU_SENSE); 581 KASSERT(req != PRU_PEERADDR); 582 KASSERT(req != PRU_SOCKADDR); 583 KASSERT(req != PRU_RCVD); 584 KASSERT(req != PRU_RCVOOB); 585 KASSERT(req != PRU_SEND); 586 KASSERT(req != PRU_SENDOOB); 587 KASSERT(req != PRU_PURGEIF); 588 589 KASSERT(solocked(so)); 590 591 if (sotounpcb(so) == NULL) 592 return EINVAL; 593 594 panic("piusrreq"); 595 596 return 0; 597 } 598 599 /* 600 * Unix domain socket option processing. 601 */ 602 int 603 uipc_ctloutput(int op, struct socket *so, struct sockopt *sopt) 604 { 605 struct unpcb *unp = sotounpcb(so); 606 int optval = 0, error = 0; 607 608 KASSERT(solocked(so)); 609 610 if (sopt->sopt_level != 0) { 611 error = ENOPROTOOPT; 612 } else switch (op) { 613 614 case PRCO_SETOPT: 615 switch (sopt->sopt_name) { 616 case LOCAL_CREDS: 617 case LOCAL_CONNWAIT: 618 error = sockopt_getint(sopt, &optval); 619 if (error) 620 break; 621 switch (sopt->sopt_name) { 622 #define OPTSET(bit) \ 623 if (optval) \ 624 unp->unp_flags |= (bit); \ 625 else \ 626 unp->unp_flags &= ~(bit); 627 628 case LOCAL_CREDS: 629 OPTSET(UNP_WANTCRED); 630 break; 631 case LOCAL_CONNWAIT: 632 OPTSET(UNP_CONNWAIT); 633 break; 634 } 635 break; 636 #undef OPTSET 637 638 default: 639 error = ENOPROTOOPT; 640 break; 641 } 642 break; 643 644 case PRCO_GETOPT: 645 sounlock(so); 646 switch (sopt->sopt_name) { 647 case LOCAL_PEEREID: 648 if (unp->unp_flags & UNP_EIDSVALID) { 649 error = sockopt_set(sopt, 650 &unp->unp_connid, sizeof(unp->unp_connid)); 651 } else { 652 error = EINVAL; 653 } 654 break; 655 case LOCAL_CREDS: 656 #define OPTBIT(bit) (unp->unp_flags & (bit) ? 1 : 0) 657 658 optval = OPTBIT(UNP_WANTCRED); 659 error = sockopt_setint(sopt, optval); 660 break; 661 #undef OPTBIT 662 663 default: 664 error = ENOPROTOOPT; 665 break; 666 } 667 solock(so); 668 break; 669 } 670 return (error); 671 } 672 673 /* 674 * Both send and receive buffers are allocated PIPSIZ bytes of buffering 675 * for stream sockets, although the total for sender and receiver is 676 * actually only PIPSIZ. 677 * Datagram sockets really use the sendspace as the maximum datagram size, 678 * and don't really want to reserve the sendspace. Their recvspace should 679 * be large enough for at least one max-size datagram plus address. 680 */ 681 #define PIPSIZ 4096 682 u_long unpst_sendspace = PIPSIZ; 683 u_long unpst_recvspace = PIPSIZ; 684 u_long unpdg_sendspace = 2*1024; /* really max datagram size */ 685 u_long unpdg_recvspace = 4*1024; 686 687 u_int unp_rights; /* files in flight */ 688 u_int unp_rights_ratio = 2; /* limit, fraction of maxfiles */ 689 690 static int 691 unp_attach(struct socket *so, int proto) 692 { 693 struct unpcb *unp = sotounpcb(so); 694 u_long sndspc, rcvspc; 695 int error; 696 697 KASSERT(unp == NULL); 698 699 switch (so->so_type) { 700 case SOCK_SEQPACKET: 701 /* FALLTHROUGH */ 702 case SOCK_STREAM: 703 if (so->so_lock == NULL) { 704 so->so_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE); 705 solock(so); 706 } 707 sndspc = unpst_sendspace; 708 rcvspc = unpst_recvspace; 709 break; 710 711 case SOCK_DGRAM: 712 if (so->so_lock == NULL) { 713 mutex_obj_hold(uipc_lock); 714 so->so_lock = uipc_lock; 715 solock(so); 716 } 717 sndspc = unpdg_sendspace; 718 rcvspc = unpdg_recvspace; 719 break; 720 721 default: 722 panic("unp_attach"); 723 } 724 725 if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) { 726 error = soreserve(so, sndspc, rcvspc); 727 if (error) { 728 return error; 729 } 730 } 731 732 unp = kmem_zalloc(sizeof(*unp), KM_SLEEP); 733 nanotime(&unp->unp_ctime); 734 unp->unp_socket = so; 735 so->so_pcb = unp; 736 737 KASSERT(solocked(so)); 738 return 0; 739 } 740 741 static void 742 unp_detach(struct socket *so) 743 { 744 struct unpcb *unp; 745 vnode_t *vp; 746 747 unp = sotounpcb(so); 748 KASSERT(unp != NULL); 749 KASSERT(solocked(so)); 750 retry: 751 if ((vp = unp->unp_vnode) != NULL) { 752 sounlock(so); 753 /* Acquire v_interlock to protect against unp_connect(). */ 754 /* XXXAD racy */ 755 mutex_enter(vp->v_interlock); 756 vp->v_socket = NULL; 757 mutex_exit(vp->v_interlock); 758 vrele(vp); 759 solock(so); 760 unp->unp_vnode = NULL; 761 } 762 if (unp->unp_conn) 763 unp_disconnect1(unp); 764 while (unp->unp_refs) { 765 KASSERT(solocked2(so, unp->unp_refs->unp_socket)); 766 if (unp_drop(unp->unp_refs, ECONNRESET)) { 767 solock(so); 768 goto retry; 769 } 770 } 771 soisdisconnected(so); 772 so->so_pcb = NULL; 773 if (unp_rights) { 774 /* 775 * Normally the receive buffer is flushed later, in sofree, 776 * but if our receive buffer holds references to files that 777 * are now garbage, we will enqueue those file references to 778 * the garbage collector and kick it into action. 779 */ 780 sorflush(so); 781 unp_free(unp); 782 unp_thread_kick(); 783 } else 784 unp_free(unp); 785 } 786 787 static int 788 unp_accept(struct socket *so, struct mbuf *nam) 789 { 790 struct unpcb *unp = sotounpcb(so); 791 struct socket *so2; 792 793 KASSERT(solocked(so)); 794 KASSERT(nam != NULL); 795 796 /* XXX code review required to determine if unp can ever be NULL */ 797 if (unp == NULL) 798 return EINVAL; 799 800 KASSERT(so->so_lock == uipc_lock); 801 /* 802 * Mark the initiating STREAM socket as connected *ONLY* 803 * after it's been accepted. This prevents a client from 804 * overrunning a server and receiving ECONNREFUSED. 805 */ 806 if (unp->unp_conn == NULL) { 807 /* 808 * This will use the empty socket and will not 809 * allocate. 810 */ 811 unp_setaddr(so, nam, true); 812 return 0; 813 } 814 so2 = unp->unp_conn->unp_socket; 815 if (so2->so_state & SS_ISCONNECTING) { 816 KASSERT(solocked2(so, so->so_head)); 817 KASSERT(solocked2(so2, so->so_head)); 818 soisconnected(so2); 819 } 820 /* 821 * If the connection is fully established, break the 822 * association with uipc_lock and give the connected 823 * pair a separate lock to share. 824 * There is a race here: sotounpcb(so2)->unp_streamlock 825 * is not locked, so when changing so2->so_lock 826 * another thread can grab it while so->so_lock is still 827 * pointing to the (locked) uipc_lock. 828 * this should be harmless, except that this makes 829 * solocked2() and solocked() unreliable. 830 * Another problem is that unp_setaddr() expects the 831 * the socket locked. Grabing sotounpcb(so2)->unp_streamlock 832 * fixes both issues. 833 */ 834 mutex_enter(sotounpcb(so2)->unp_streamlock); 835 unp_setpeerlocks(so2, so); 836 /* 837 * Only now return peer's address, as we may need to 838 * block in order to allocate memory. 839 * 840 * XXX Minor race: connection can be broken while 841 * lock is dropped in unp_setaddr(). We will return 842 * error == 0 and sun_noname as the peer address. 843 */ 844 unp_setaddr(so, nam, true); 845 /* so_lock now points to unp_streamlock */ 846 mutex_exit(so2->so_lock); 847 return 0; 848 } 849 850 static int 851 unp_ioctl(struct socket *so, u_long cmd, void *nam, struct ifnet *ifp) 852 { 853 return EOPNOTSUPP; 854 } 855 856 static int 857 unp_stat(struct socket *so, struct stat *ub) 858 { 859 struct unpcb *unp; 860 struct socket *so2; 861 862 KASSERT(solocked(so)); 863 864 unp = sotounpcb(so); 865 if (unp == NULL) 866 return EINVAL; 867 868 ub->st_blksize = so->so_snd.sb_hiwat; 869 switch (so->so_type) { 870 case SOCK_SEQPACKET: /* FALLTHROUGH */ 871 case SOCK_STREAM: 872 if (unp->unp_conn == 0) 873 break; 874 875 so2 = unp->unp_conn->unp_socket; 876 KASSERT(solocked2(so, so2)); 877 ub->st_blksize += so2->so_rcv.sb_cc; 878 break; 879 default: 880 break; 881 } 882 ub->st_dev = NODEV; 883 if (unp->unp_ino == 0) 884 unp->unp_ino = unp_ino++; 885 ub->st_atimespec = ub->st_mtimespec = ub->st_ctimespec = unp->unp_ctime; 886 ub->st_ino = unp->unp_ino; 887 return (0); 888 } 889 890 static int 891 unp_peeraddr(struct socket *so, struct mbuf *nam) 892 { 893 KASSERT(solocked(so)); 894 KASSERT(sotounpcb(so) != NULL); 895 KASSERT(nam != NULL); 896 897 unp_setaddr(so, nam, true); 898 return 0; 899 } 900 901 static int 902 unp_sockaddr(struct socket *so, struct mbuf *nam) 903 { 904 KASSERT(solocked(so)); 905 KASSERT(sotounpcb(so) != NULL); 906 KASSERT(nam != NULL); 907 908 unp_setaddr(so, nam, false); 909 return 0; 910 } 911 912 /* 913 * Allocate the new sockaddr. We have to allocate one 914 * extra byte so that we can ensure that the pathname 915 * is nul-terminated. Note that unlike linux, we don't 916 * include in the address length the NUL in the path 917 * component, because doing so, would exceed sizeof(sockaddr_un) 918 * for fully occupied pathnames. Linux is also inconsistent, 919 * because it does not include the NUL in the length of 920 * what it calls "abstract" unix sockets. 921 */ 922 static struct sockaddr_un * 923 makeun(struct mbuf *nam, size_t *addrlen) 924 { 925 struct sockaddr_un *sun; 926 927 *addrlen = nam->m_len + 1; 928 sun = malloc(*addrlen, M_SONAME, M_WAITOK); 929 m_copydata(nam, 0, nam->m_len, (void *)sun); 930 *(((char *)sun) + nam->m_len) = '\0'; 931 return sun; 932 } 933 934 static int 935 unp_bind(struct socket *so, struct mbuf *nam, struct lwp *l) 936 { 937 struct sockaddr_un *sun; 938 struct unpcb *unp; 939 vnode_t *vp; 940 struct vattr vattr; 941 size_t addrlen; 942 int error; 943 struct pathbuf *pb; 944 struct nameidata nd; 945 proc_t *p; 946 947 unp = sotounpcb(so); 948 949 KASSERT(solocked(so)); 950 KASSERT(unp != NULL); 951 KASSERT(nam != NULL); 952 953 if (unp->unp_vnode != NULL) 954 return (EINVAL); 955 if ((unp->unp_flags & UNP_BUSY) != 0) { 956 /* 957 * EALREADY may not be strictly accurate, but since this 958 * is a major application error it's hardly a big deal. 959 */ 960 return (EALREADY); 961 } 962 unp->unp_flags |= UNP_BUSY; 963 sounlock(so); 964 965 p = l->l_proc; 966 sun = makeun(nam, &addrlen); 967 968 pb = pathbuf_create(sun->sun_path); 969 if (pb == NULL) { 970 error = ENOMEM; 971 goto bad; 972 } 973 NDINIT(&nd, CREATE, FOLLOW | LOCKPARENT | TRYEMULROOT, pb); 974 975 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */ 976 if ((error = namei(&nd)) != 0) { 977 pathbuf_destroy(pb); 978 goto bad; 979 } 980 vp = nd.ni_vp; 981 if (vp != NULL) { 982 VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd); 983 if (nd.ni_dvp == vp) 984 vrele(nd.ni_dvp); 985 else 986 vput(nd.ni_dvp); 987 vrele(vp); 988 pathbuf_destroy(pb); 989 error = EADDRINUSE; 990 goto bad; 991 } 992 vattr_null(&vattr); 993 vattr.va_type = VSOCK; 994 vattr.va_mode = ACCESSPERMS & ~(p->p_cwdi->cwdi_cmask); 995 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr); 996 if (error) { 997 vput(nd.ni_dvp); 998 pathbuf_destroy(pb); 999 goto bad; 1000 } 1001 vp = nd.ni_vp; 1002 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1003 solock(so); 1004 vp->v_socket = unp->unp_socket; 1005 unp->unp_vnode = vp; 1006 unp->unp_addrlen = addrlen; 1007 unp->unp_addr = sun; 1008 unp->unp_connid.unp_pid = p->p_pid; 1009 unp->unp_connid.unp_euid = kauth_cred_geteuid(l->l_cred); 1010 unp->unp_connid.unp_egid = kauth_cred_getegid(l->l_cred); 1011 unp->unp_flags |= UNP_EIDSBIND; 1012 VOP_UNLOCK(vp); 1013 vput(nd.ni_dvp); 1014 unp->unp_flags &= ~UNP_BUSY; 1015 pathbuf_destroy(pb); 1016 return (0); 1017 1018 bad: 1019 free(sun, M_SONAME); 1020 solock(so); 1021 unp->unp_flags &= ~UNP_BUSY; 1022 return (error); 1023 } 1024 1025 static int 1026 unp_listen(struct socket *so, struct lwp *l) 1027 { 1028 struct unpcb *unp = sotounpcb(so); 1029 1030 KASSERT(solocked(so)); 1031 KASSERT(unp != NULL); 1032 1033 /* 1034 * If the socket can accept a connection, it must be 1035 * locked by uipc_lock. 1036 */ 1037 unp_resetlock(so); 1038 if (unp->unp_vnode == NULL) 1039 return EINVAL; 1040 1041 return 0; 1042 } 1043 1044 static int 1045 unp_disconnect(struct socket *so) 1046 { 1047 KASSERT(solocked(so)); 1048 KASSERT(sotounpcb(so) != NULL); 1049 1050 unp_disconnect1(sotounpcb(so)); 1051 return 0; 1052 } 1053 1054 static int 1055 unp_shutdown(struct socket *so) 1056 { 1057 KASSERT(solocked(so)); 1058 KASSERT(sotounpcb(so) != NULL); 1059 1060 socantsendmore(so); 1061 unp_shutdown1(sotounpcb(so)); 1062 return 0; 1063 } 1064 1065 static int 1066 unp_abort(struct socket *so) 1067 { 1068 KASSERT(solocked(so)); 1069 KASSERT(sotounpcb(so) != NULL); 1070 1071 (void)unp_drop(sotounpcb(so), ECONNABORTED); 1072 KASSERT(so->so_head == NULL); 1073 KASSERT(so->so_pcb != NULL); 1074 unp_detach(so); 1075 return 0; 1076 } 1077 1078 static int 1079 unp_connect1(struct socket *so, struct socket *so2, struct lwp *l) 1080 { 1081 struct unpcb *unp = sotounpcb(so); 1082 struct unpcb *unp2; 1083 1084 if (so2->so_type != so->so_type) 1085 return EPROTOTYPE; 1086 1087 /* 1088 * All three sockets involved must be locked by same lock: 1089 * 1090 * local endpoint (so) 1091 * remote endpoint (so2) 1092 * queue head (so2->so_head, only if PR_CONNREQUIRED) 1093 */ 1094 KASSERT(solocked2(so, so2)); 1095 KASSERT(so->so_head == NULL); 1096 if (so2->so_head != NULL) { 1097 KASSERT(so2->so_lock == uipc_lock); 1098 KASSERT(solocked2(so2, so2->so_head)); 1099 } 1100 1101 unp2 = sotounpcb(so2); 1102 unp->unp_conn = unp2; 1103 1104 if ((so->so_proto->pr_flags & PR_CONNREQUIRED) != 0) { 1105 unp2->unp_connid.unp_pid = l->l_proc->p_pid; 1106 unp2->unp_connid.unp_euid = kauth_cred_geteuid(l->l_cred); 1107 unp2->unp_connid.unp_egid = kauth_cred_getegid(l->l_cred); 1108 unp2->unp_flags |= UNP_EIDSVALID; 1109 if (unp2->unp_flags & UNP_EIDSBIND) { 1110 unp->unp_connid = unp2->unp_connid; 1111 unp->unp_flags |= UNP_EIDSVALID; 1112 } 1113 } 1114 1115 switch (so->so_type) { 1116 1117 case SOCK_DGRAM: 1118 unp->unp_nextref = unp2->unp_refs; 1119 unp2->unp_refs = unp; 1120 soisconnected(so); 1121 break; 1122 1123 case SOCK_SEQPACKET: /* FALLTHROUGH */ 1124 case SOCK_STREAM: 1125 1126 /* 1127 * SOCK_SEQPACKET and SOCK_STREAM cases are handled by callers 1128 * which are unp_connect() or unp_connect2(). 1129 */ 1130 1131 break; 1132 1133 default: 1134 panic("unp_connect1"); 1135 } 1136 1137 return 0; 1138 } 1139 1140 int 1141 unp_connect(struct socket *so, struct mbuf *nam, struct lwp *l) 1142 { 1143 struct sockaddr_un *sun; 1144 vnode_t *vp; 1145 struct socket *so2, *so3; 1146 struct unpcb *unp, *unp2, *unp3; 1147 size_t addrlen; 1148 int error; 1149 struct pathbuf *pb; 1150 struct nameidata nd; 1151 1152 unp = sotounpcb(so); 1153 if ((unp->unp_flags & UNP_BUSY) != 0) { 1154 /* 1155 * EALREADY may not be strictly accurate, but since this 1156 * is a major application error it's hardly a big deal. 1157 */ 1158 return (EALREADY); 1159 } 1160 unp->unp_flags |= UNP_BUSY; 1161 sounlock(so); 1162 1163 sun = makeun(nam, &addrlen); 1164 pb = pathbuf_create(sun->sun_path); 1165 if (pb == NULL) { 1166 error = ENOMEM; 1167 goto bad2; 1168 } 1169 1170 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb); 1171 1172 if ((error = namei(&nd)) != 0) { 1173 pathbuf_destroy(pb); 1174 goto bad2; 1175 } 1176 vp = nd.ni_vp; 1177 if (vp->v_type != VSOCK) { 1178 error = ENOTSOCK; 1179 goto bad; 1180 } 1181 pathbuf_destroy(pb); 1182 if ((error = VOP_ACCESS(vp, VWRITE, l->l_cred)) != 0) 1183 goto bad; 1184 /* Acquire v_interlock to protect against unp_detach(). */ 1185 mutex_enter(vp->v_interlock); 1186 so2 = vp->v_socket; 1187 if (so2 == NULL) { 1188 mutex_exit(vp->v_interlock); 1189 error = ECONNREFUSED; 1190 goto bad; 1191 } 1192 if (so->so_type != so2->so_type) { 1193 mutex_exit(vp->v_interlock); 1194 error = EPROTOTYPE; 1195 goto bad; 1196 } 1197 solock(so); 1198 unp_resetlock(so); 1199 mutex_exit(vp->v_interlock); 1200 if ((so->so_proto->pr_flags & PR_CONNREQUIRED) != 0) { 1201 /* 1202 * This may seem somewhat fragile but is OK: if we can 1203 * see SO_ACCEPTCONN set on the endpoint, then it must 1204 * be locked by the domain-wide uipc_lock. 1205 */ 1206 KASSERT((so2->so_options & SO_ACCEPTCONN) == 0 || 1207 so2->so_lock == uipc_lock); 1208 if ((so2->so_options & SO_ACCEPTCONN) == 0 || 1209 (so3 = sonewconn(so2, false)) == NULL) { 1210 error = ECONNREFUSED; 1211 sounlock(so); 1212 goto bad; 1213 } 1214 unp2 = sotounpcb(so2); 1215 unp3 = sotounpcb(so3); 1216 if (unp2->unp_addr) { 1217 unp3->unp_addr = malloc(unp2->unp_addrlen, 1218 M_SONAME, M_WAITOK); 1219 memcpy(unp3->unp_addr, unp2->unp_addr, 1220 unp2->unp_addrlen); 1221 unp3->unp_addrlen = unp2->unp_addrlen; 1222 } 1223 unp3->unp_flags = unp2->unp_flags; 1224 so2 = so3; 1225 } 1226 error = unp_connect1(so, so2, l); 1227 if (error) { 1228 sounlock(so); 1229 goto bad; 1230 } 1231 unp2 = sotounpcb(so2); 1232 switch (so->so_type) { 1233 1234 /* 1235 * SOCK_DGRAM and default cases are handled in prior call to 1236 * unp_connect1(), do not add a default case without fixing 1237 * unp_connect1(). 1238 */ 1239 1240 case SOCK_SEQPACKET: /* FALLTHROUGH */ 1241 case SOCK_STREAM: 1242 unp2->unp_conn = unp; 1243 if ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT) 1244 soisconnecting(so); 1245 else 1246 soisconnected(so); 1247 soisconnected(so2); 1248 /* 1249 * If the connection is fully established, break the 1250 * association with uipc_lock and give the connected 1251 * pair a seperate lock to share. 1252 */ 1253 KASSERT(so2->so_head != NULL); 1254 unp_setpeerlocks(so, so2); 1255 break; 1256 1257 } 1258 sounlock(so); 1259 bad: 1260 vput(vp); 1261 bad2: 1262 free(sun, M_SONAME); 1263 solock(so); 1264 unp->unp_flags &= ~UNP_BUSY; 1265 return (error); 1266 } 1267 1268 int 1269 unp_connect2(struct socket *so, struct socket *so2) 1270 { 1271 struct unpcb *unp = sotounpcb(so); 1272 struct unpcb *unp2; 1273 int error = 0; 1274 1275 KASSERT(solocked2(so, so2)); 1276 1277 error = unp_connect1(so, so2, curlwp); 1278 if (error) 1279 return error; 1280 1281 unp2 = sotounpcb(so2); 1282 switch (so->so_type) { 1283 1284 /* 1285 * SOCK_DGRAM and default cases are handled in prior call to 1286 * unp_connect1(), do not add a default case without fixing 1287 * unp_connect1(). 1288 */ 1289 1290 case SOCK_SEQPACKET: /* FALLTHROUGH */ 1291 case SOCK_STREAM: 1292 unp2->unp_conn = unp; 1293 if ((so->so_proto->pr_flags & PR_CONNREQUIRED) != 0) { 1294 unp->unp_connid = unp2->unp_connid; 1295 unp->unp_flags |= UNP_EIDSVALID; 1296 } 1297 soisconnected(so); 1298 soisconnected(so2); 1299 break; 1300 1301 } 1302 return error; 1303 } 1304 1305 static void 1306 unp_disconnect1(struct unpcb *unp) 1307 { 1308 struct unpcb *unp2 = unp->unp_conn; 1309 struct socket *so; 1310 1311 if (unp2 == 0) 1312 return; 1313 unp->unp_conn = 0; 1314 so = unp->unp_socket; 1315 switch (so->so_type) { 1316 case SOCK_DGRAM: 1317 if (unp2->unp_refs == unp) 1318 unp2->unp_refs = unp->unp_nextref; 1319 else { 1320 unp2 = unp2->unp_refs; 1321 for (;;) { 1322 KASSERT(solocked2(so, unp2->unp_socket)); 1323 if (unp2 == 0) 1324 panic("unp_disconnect1"); 1325 if (unp2->unp_nextref == unp) 1326 break; 1327 unp2 = unp2->unp_nextref; 1328 } 1329 unp2->unp_nextref = unp->unp_nextref; 1330 } 1331 unp->unp_nextref = 0; 1332 so->so_state &= ~SS_ISCONNECTED; 1333 break; 1334 1335 case SOCK_SEQPACKET: /* FALLTHROUGH */ 1336 case SOCK_STREAM: 1337 KASSERT(solocked2(so, unp2->unp_socket)); 1338 soisdisconnected(so); 1339 unp2->unp_conn = 0; 1340 soisdisconnected(unp2->unp_socket); 1341 break; 1342 } 1343 } 1344 1345 static void 1346 unp_shutdown1(struct unpcb *unp) 1347 { 1348 struct socket *so; 1349 1350 switch(unp->unp_socket->so_type) { 1351 case SOCK_SEQPACKET: /* FALLTHROUGH */ 1352 case SOCK_STREAM: 1353 if (unp->unp_conn && (so = unp->unp_conn->unp_socket)) 1354 socantrcvmore(so); 1355 break; 1356 default: 1357 break; 1358 } 1359 } 1360 1361 static bool 1362 unp_drop(struct unpcb *unp, int errno) 1363 { 1364 struct socket *so = unp->unp_socket; 1365 1366 KASSERT(solocked(so)); 1367 1368 so->so_error = errno; 1369 unp_disconnect1(unp); 1370 if (so->so_head) { 1371 so->so_pcb = NULL; 1372 /* sofree() drops the socket lock */ 1373 sofree(so); 1374 unp_free(unp); 1375 return true; 1376 } 1377 return false; 1378 } 1379 1380 #ifdef notdef 1381 unp_drain(void) 1382 { 1383 1384 } 1385 #endif 1386 1387 int 1388 unp_externalize(struct mbuf *rights, struct lwp *l, int flags) 1389 { 1390 struct cmsghdr * const cm = mtod(rights, struct cmsghdr *); 1391 struct proc * const p = l->l_proc; 1392 file_t **rp; 1393 int error = 0; 1394 1395 const size_t nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) / 1396 sizeof(file_t *); 1397 if (nfds == 0) 1398 goto noop; 1399 1400 int * const fdp = kmem_alloc(nfds * sizeof(int), KM_SLEEP); 1401 rw_enter(&p->p_cwdi->cwdi_lock, RW_READER); 1402 1403 /* Make sure the recipient should be able to see the files.. */ 1404 rp = (file_t **)CMSG_DATA(cm); 1405 for (size_t i = 0; i < nfds; i++) { 1406 file_t * const fp = *rp++; 1407 if (fp == NULL) { 1408 error = EINVAL; 1409 goto out; 1410 } 1411 /* 1412 * If we are in a chroot'ed directory, and 1413 * someone wants to pass us a directory, make 1414 * sure it's inside the subtree we're allowed 1415 * to access. 1416 */ 1417 if (p->p_cwdi->cwdi_rdir != NULL && fp->f_type == DTYPE_VNODE) { 1418 vnode_t *vp = fp->f_vnode; 1419 if ((vp->v_type == VDIR) && 1420 !vn_isunder(vp, p->p_cwdi->cwdi_rdir, l)) { 1421 error = EPERM; 1422 goto out; 1423 } 1424 } 1425 } 1426 1427 restart: 1428 /* 1429 * First loop -- allocate file descriptor table slots for the 1430 * new files. 1431 */ 1432 for (size_t i = 0; i < nfds; i++) { 1433 if ((error = fd_alloc(p, 0, &fdp[i])) != 0) { 1434 /* 1435 * Back out what we've done so far. 1436 */ 1437 while (i-- > 0) { 1438 fd_abort(p, NULL, fdp[i]); 1439 } 1440 if (error == ENOSPC) { 1441 fd_tryexpand(p); 1442 error = 0; 1443 goto restart; 1444 } 1445 /* 1446 * This is the error that has historically 1447 * been returned, and some callers may 1448 * expect it. 1449 */ 1450 error = EMSGSIZE; 1451 goto out; 1452 } 1453 } 1454 1455 /* 1456 * Now that adding them has succeeded, update all of the 1457 * file passing state and affix the descriptors. 1458 */ 1459 rp = (file_t **)CMSG_DATA(cm); 1460 int *ofdp = (int *)CMSG_DATA(cm); 1461 for (size_t i = 0; i < nfds; i++) { 1462 file_t * const fp = *rp++; 1463 const int fd = fdp[i]; 1464 atomic_dec_uint(&unp_rights); 1465 fd_set_exclose(l, fd, (flags & O_CLOEXEC) != 0); 1466 fd_affix(p, fp, fd); 1467 /* 1468 * Done with this file pointer, replace it with a fd; 1469 */ 1470 *ofdp++ = fd; 1471 mutex_enter(&fp->f_lock); 1472 fp->f_msgcount--; 1473 mutex_exit(&fp->f_lock); 1474 /* 1475 * Note that fd_affix() adds a reference to the file. 1476 * The file may already have been closed by another 1477 * LWP in the process, so we must drop the reference 1478 * added by unp_internalize() with closef(). 1479 */ 1480 closef(fp); 1481 } 1482 1483 /* 1484 * Adjust length, in case of transition from large file_t 1485 * pointers to ints. 1486 */ 1487 if (sizeof(file_t *) != sizeof(int)) { 1488 cm->cmsg_len = CMSG_LEN(nfds * sizeof(int)); 1489 rights->m_len = CMSG_SPACE(nfds * sizeof(int)); 1490 } 1491 out: 1492 if (__predict_false(error != 0)) { 1493 file_t **const fpp = (file_t **)CMSG_DATA(cm); 1494 for (size_t i = 0; i < nfds; i++) 1495 unp_discard_now(fpp[i]); 1496 /* 1497 * Truncate the array so that nobody will try to interpret 1498 * what is now garbage in it. 1499 */ 1500 cm->cmsg_len = CMSG_LEN(0); 1501 rights->m_len = CMSG_SPACE(0); 1502 } 1503 rw_exit(&p->p_cwdi->cwdi_lock); 1504 kmem_free(fdp, nfds * sizeof(int)); 1505 1506 noop: 1507 /* 1508 * Don't disclose kernel memory in the alignment space. 1509 */ 1510 KASSERT(cm->cmsg_len <= rights->m_len); 1511 memset(&mtod(rights, char *)[cm->cmsg_len], 0, rights->m_len - 1512 cm->cmsg_len); 1513 return error; 1514 } 1515 1516 static int 1517 unp_internalize(struct mbuf **controlp) 1518 { 1519 filedesc_t *fdescp = curlwp->l_fd; 1520 struct mbuf *control = *controlp; 1521 struct cmsghdr *newcm, *cm = mtod(control, struct cmsghdr *); 1522 file_t **rp, **files; 1523 file_t *fp; 1524 int i, fd, *fdp; 1525 int nfds, error; 1526 u_int maxmsg; 1527 1528 error = 0; 1529 newcm = NULL; 1530 1531 /* Sanity check the control message header. */ 1532 if (cm->cmsg_type != SCM_RIGHTS || cm->cmsg_level != SOL_SOCKET || 1533 cm->cmsg_len > control->m_len || 1534 cm->cmsg_len < CMSG_ALIGN(sizeof(*cm))) 1535 return (EINVAL); 1536 1537 /* 1538 * Verify that the file descriptors are valid, and acquire 1539 * a reference to each. 1540 */ 1541 nfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) / sizeof(int); 1542 fdp = (int *)CMSG_DATA(cm); 1543 maxmsg = maxfiles / unp_rights_ratio; 1544 for (i = 0; i < nfds; i++) { 1545 fd = *fdp++; 1546 if (atomic_inc_uint_nv(&unp_rights) > maxmsg) { 1547 atomic_dec_uint(&unp_rights); 1548 nfds = i; 1549 error = EAGAIN; 1550 goto out; 1551 } 1552 if ((fp = fd_getfile(fd)) == NULL 1553 || fp->f_type == DTYPE_KQUEUE) { 1554 if (fp) 1555 fd_putfile(fd); 1556 atomic_dec_uint(&unp_rights); 1557 nfds = i; 1558 error = EBADF; 1559 goto out; 1560 } 1561 } 1562 1563 /* Allocate new space and copy header into it. */ 1564 newcm = malloc(CMSG_SPACE(nfds * sizeof(file_t *)), M_MBUF, M_WAITOK); 1565 if (newcm == NULL) { 1566 error = E2BIG; 1567 goto out; 1568 } 1569 memcpy(newcm, cm, sizeof(struct cmsghdr)); 1570 files = (file_t **)CMSG_DATA(newcm); 1571 1572 /* 1573 * Transform the file descriptors into file_t pointers, in 1574 * reverse order so that if pointers are bigger than ints, the 1575 * int won't get until we're done. No need to lock, as we have 1576 * already validated the descriptors with fd_getfile(). 1577 */ 1578 fdp = (int *)CMSG_DATA(cm) + nfds; 1579 rp = files + nfds; 1580 for (i = 0; i < nfds; i++) { 1581 fp = fdescp->fd_dt->dt_ff[*--fdp]->ff_file; 1582 KASSERT(fp != NULL); 1583 mutex_enter(&fp->f_lock); 1584 *--rp = fp; 1585 fp->f_count++; 1586 fp->f_msgcount++; 1587 mutex_exit(&fp->f_lock); 1588 } 1589 1590 out: 1591 /* Release descriptor references. */ 1592 fdp = (int *)CMSG_DATA(cm); 1593 for (i = 0; i < nfds; i++) { 1594 fd_putfile(*fdp++); 1595 if (error != 0) { 1596 atomic_dec_uint(&unp_rights); 1597 } 1598 } 1599 1600 if (error == 0) { 1601 if (control->m_flags & M_EXT) { 1602 m_freem(control); 1603 *controlp = control = m_get(M_WAIT, MT_CONTROL); 1604 } 1605 MEXTADD(control, newcm, CMSG_SPACE(nfds * sizeof(file_t *)), 1606 M_MBUF, NULL, NULL); 1607 cm = newcm; 1608 /* 1609 * Adjust message & mbuf to note amount of space 1610 * actually used. 1611 */ 1612 cm->cmsg_len = CMSG_LEN(nfds * sizeof(file_t *)); 1613 control->m_len = CMSG_SPACE(nfds * sizeof(file_t *)); 1614 } 1615 1616 return error; 1617 } 1618 1619 struct mbuf * 1620 unp_addsockcred(struct lwp *l, struct mbuf *control) 1621 { 1622 struct sockcred *sc; 1623 struct mbuf *m; 1624 void *p; 1625 1626 m = sbcreatecontrol1(&p, SOCKCREDSIZE(kauth_cred_ngroups(l->l_cred)), 1627 SCM_CREDS, SOL_SOCKET, M_WAITOK); 1628 if (m == NULL) 1629 return control; 1630 1631 sc = p; 1632 sc->sc_uid = kauth_cred_getuid(l->l_cred); 1633 sc->sc_euid = kauth_cred_geteuid(l->l_cred); 1634 sc->sc_gid = kauth_cred_getgid(l->l_cred); 1635 sc->sc_egid = kauth_cred_getegid(l->l_cred); 1636 sc->sc_ngroups = kauth_cred_ngroups(l->l_cred); 1637 1638 for (int i = 0; i < sc->sc_ngroups; i++) 1639 sc->sc_groups[i] = kauth_cred_group(l->l_cred, i); 1640 1641 return m_add(control, m); 1642 } 1643 1644 /* 1645 * Do a mark-sweep GC of files in the system, to free up any which are 1646 * caught in flight to an about-to-be-closed socket. Additionally, 1647 * process deferred file closures. 1648 */ 1649 static void 1650 unp_gc(file_t *dp) 1651 { 1652 extern struct domain unixdomain; 1653 file_t *fp, *np; 1654 struct socket *so, *so1; 1655 u_int i, oflags, rflags; 1656 bool didwork; 1657 1658 KASSERT(curlwp == unp_thread_lwp); 1659 KASSERT(mutex_owned(&filelist_lock)); 1660 1661 /* 1662 * First, process deferred file closures. 1663 */ 1664 while (!SLIST_EMPTY(&unp_thread_discard)) { 1665 fp = SLIST_FIRST(&unp_thread_discard); 1666 KASSERT(fp->f_unpcount > 0); 1667 KASSERT(fp->f_count > 0); 1668 KASSERT(fp->f_msgcount > 0); 1669 KASSERT(fp->f_count >= fp->f_unpcount); 1670 KASSERT(fp->f_count >= fp->f_msgcount); 1671 KASSERT(fp->f_msgcount >= fp->f_unpcount); 1672 SLIST_REMOVE_HEAD(&unp_thread_discard, f_unplist); 1673 i = fp->f_unpcount; 1674 fp->f_unpcount = 0; 1675 mutex_exit(&filelist_lock); 1676 for (; i != 0; i--) { 1677 unp_discard_now(fp); 1678 } 1679 mutex_enter(&filelist_lock); 1680 } 1681 1682 /* 1683 * Clear mark bits. Ensure that we don't consider new files 1684 * entering the file table during this loop (they will not have 1685 * FSCAN set). 1686 */ 1687 unp_defer = 0; 1688 LIST_FOREACH(fp, &filehead, f_list) { 1689 for (oflags = fp->f_flag;; oflags = rflags) { 1690 rflags = atomic_cas_uint(&fp->f_flag, oflags, 1691 (oflags | FSCAN) & ~(FMARK|FDEFER)); 1692 if (__predict_true(oflags == rflags)) { 1693 break; 1694 } 1695 } 1696 } 1697 1698 /* 1699 * Iterate over the set of sockets, marking ones believed (based on 1700 * refcount) to be referenced from a process, and marking for rescan 1701 * sockets which are queued on a socket. Recan continues descending 1702 * and searching for sockets referenced by sockets (FDEFER), until 1703 * there are no more socket->socket references to be discovered. 1704 */ 1705 do { 1706 didwork = false; 1707 for (fp = LIST_FIRST(&filehead); fp != NULL; fp = np) { 1708 KASSERT(mutex_owned(&filelist_lock)); 1709 np = LIST_NEXT(fp, f_list); 1710 mutex_enter(&fp->f_lock); 1711 if ((fp->f_flag & FDEFER) != 0) { 1712 atomic_and_uint(&fp->f_flag, ~FDEFER); 1713 unp_defer--; 1714 KASSERT(fp->f_count != 0); 1715 } else { 1716 if (fp->f_count == 0 || 1717 (fp->f_flag & FMARK) != 0 || 1718 fp->f_count == fp->f_msgcount || 1719 fp->f_unpcount != 0) { 1720 mutex_exit(&fp->f_lock); 1721 continue; 1722 } 1723 } 1724 atomic_or_uint(&fp->f_flag, FMARK); 1725 1726 if (fp->f_type != DTYPE_SOCKET || 1727 (so = fp->f_socket) == NULL || 1728 so->so_proto->pr_domain != &unixdomain || 1729 (so->so_proto->pr_flags & PR_RIGHTS) == 0) { 1730 mutex_exit(&fp->f_lock); 1731 continue; 1732 } 1733 1734 /* Gain file ref, mark our position, and unlock. */ 1735 didwork = true; 1736 LIST_INSERT_AFTER(fp, dp, f_list); 1737 fp->f_count++; 1738 mutex_exit(&fp->f_lock); 1739 mutex_exit(&filelist_lock); 1740 1741 /* 1742 * Mark files referenced from sockets queued on the 1743 * accept queue as well. 1744 */ 1745 solock(so); 1746 unp_scan(so->so_rcv.sb_mb, unp_mark, 0); 1747 if ((so->so_options & SO_ACCEPTCONN) != 0) { 1748 TAILQ_FOREACH(so1, &so->so_q0, so_qe) { 1749 unp_scan(so1->so_rcv.sb_mb, unp_mark, 0); 1750 } 1751 TAILQ_FOREACH(so1, &so->so_q, so_qe) { 1752 unp_scan(so1->so_rcv.sb_mb, unp_mark, 0); 1753 } 1754 } 1755 sounlock(so); 1756 1757 /* Re-lock and restart from where we left off. */ 1758 closef(fp); 1759 mutex_enter(&filelist_lock); 1760 np = LIST_NEXT(dp, f_list); 1761 LIST_REMOVE(dp, f_list); 1762 } 1763 /* 1764 * Bail early if we did nothing in the loop above. Could 1765 * happen because of concurrent activity causing unp_defer 1766 * to get out of sync. 1767 */ 1768 } while (unp_defer != 0 && didwork); 1769 1770 /* 1771 * Sweep pass. 1772 * 1773 * We grab an extra reference to each of the files that are 1774 * not otherwise accessible and then free the rights that are 1775 * stored in messages on them. 1776 */ 1777 for (fp = LIST_FIRST(&filehead); fp != NULL; fp = np) { 1778 KASSERT(mutex_owned(&filelist_lock)); 1779 np = LIST_NEXT(fp, f_list); 1780 mutex_enter(&fp->f_lock); 1781 1782 /* 1783 * Ignore non-sockets. 1784 * Ignore dead sockets, or sockets with pending close. 1785 * Ignore sockets obviously referenced elsewhere. 1786 * Ignore sockets marked as referenced by our scan. 1787 * Ignore new sockets that did not exist during the scan. 1788 */ 1789 if (fp->f_type != DTYPE_SOCKET || 1790 fp->f_count == 0 || fp->f_unpcount != 0 || 1791 fp->f_count != fp->f_msgcount || 1792 (fp->f_flag & (FMARK | FSCAN)) != FSCAN) { 1793 mutex_exit(&fp->f_lock); 1794 continue; 1795 } 1796 1797 /* Gain file ref, mark our position, and unlock. */ 1798 LIST_INSERT_AFTER(fp, dp, f_list); 1799 fp->f_count++; 1800 mutex_exit(&fp->f_lock); 1801 mutex_exit(&filelist_lock); 1802 1803 /* 1804 * Flush all data from the socket's receive buffer. 1805 * This will cause files referenced only by the 1806 * socket to be queued for close. 1807 */ 1808 so = fp->f_socket; 1809 solock(so); 1810 sorflush(so); 1811 sounlock(so); 1812 1813 /* Re-lock and restart from where we left off. */ 1814 closef(fp); 1815 mutex_enter(&filelist_lock); 1816 np = LIST_NEXT(dp, f_list); 1817 LIST_REMOVE(dp, f_list); 1818 } 1819 } 1820 1821 /* 1822 * Garbage collector thread. While SCM_RIGHTS messages are in transit, 1823 * wake once per second to garbage collect. Run continually while we 1824 * have deferred closes to process. 1825 */ 1826 static void 1827 unp_thread(void *cookie) 1828 { 1829 file_t *dp; 1830 1831 /* Allocate a dummy file for our scans. */ 1832 if ((dp = fgetdummy()) == NULL) { 1833 panic("unp_thread"); 1834 } 1835 1836 mutex_enter(&filelist_lock); 1837 for (;;) { 1838 KASSERT(mutex_owned(&filelist_lock)); 1839 if (SLIST_EMPTY(&unp_thread_discard)) { 1840 if (unp_rights != 0) { 1841 (void)cv_timedwait(&unp_thread_cv, 1842 &filelist_lock, hz); 1843 } else { 1844 cv_wait(&unp_thread_cv, &filelist_lock); 1845 } 1846 } 1847 unp_gc(dp); 1848 } 1849 /* NOTREACHED */ 1850 } 1851 1852 /* 1853 * Kick the garbage collector into action if there is something for 1854 * it to process. 1855 */ 1856 static void 1857 unp_thread_kick(void) 1858 { 1859 1860 if (!SLIST_EMPTY(&unp_thread_discard) || unp_rights != 0) { 1861 mutex_enter(&filelist_lock); 1862 cv_signal(&unp_thread_cv); 1863 mutex_exit(&filelist_lock); 1864 } 1865 } 1866 1867 void 1868 unp_dispose(struct mbuf *m) 1869 { 1870 1871 if (m) 1872 unp_scan(m, unp_discard_later, 1); 1873 } 1874 1875 void 1876 unp_scan(struct mbuf *m0, void (*op)(file_t *), int discard) 1877 { 1878 struct mbuf *m; 1879 file_t **rp, *fp; 1880 struct cmsghdr *cm; 1881 int i, qfds; 1882 1883 while (m0) { 1884 for (m = m0; m; m = m->m_next) { 1885 if (m->m_type != MT_CONTROL || 1886 m->m_len < sizeof(*cm)) { 1887 continue; 1888 } 1889 cm = mtod(m, struct cmsghdr *); 1890 if (cm->cmsg_level != SOL_SOCKET || 1891 cm->cmsg_type != SCM_RIGHTS) 1892 continue; 1893 qfds = (cm->cmsg_len - CMSG_ALIGN(sizeof(*cm))) 1894 / sizeof(file_t *); 1895 rp = (file_t **)CMSG_DATA(cm); 1896 for (i = 0; i < qfds; i++) { 1897 fp = *rp; 1898 if (discard) { 1899 *rp = 0; 1900 } 1901 (*op)(fp); 1902 rp++; 1903 } 1904 } 1905 m0 = m0->m_nextpkt; 1906 } 1907 } 1908 1909 void 1910 unp_mark(file_t *fp) 1911 { 1912 1913 if (fp == NULL) 1914 return; 1915 1916 /* If we're already deferred, don't screw up the defer count */ 1917 mutex_enter(&fp->f_lock); 1918 if (fp->f_flag & (FMARK | FDEFER)) { 1919 mutex_exit(&fp->f_lock); 1920 return; 1921 } 1922 1923 /* 1924 * Minimize the number of deferrals... Sockets are the only type of 1925 * file which can hold references to another file, so just mark 1926 * other files, and defer unmarked sockets for the next pass. 1927 */ 1928 if (fp->f_type == DTYPE_SOCKET) { 1929 unp_defer++; 1930 KASSERT(fp->f_count != 0); 1931 atomic_or_uint(&fp->f_flag, FDEFER); 1932 } else { 1933 atomic_or_uint(&fp->f_flag, FMARK); 1934 } 1935 mutex_exit(&fp->f_lock); 1936 } 1937 1938 static void 1939 unp_discard_now(file_t *fp) 1940 { 1941 1942 if (fp == NULL) 1943 return; 1944 1945 KASSERT(fp->f_count > 0); 1946 KASSERT(fp->f_msgcount > 0); 1947 1948 mutex_enter(&fp->f_lock); 1949 fp->f_msgcount--; 1950 mutex_exit(&fp->f_lock); 1951 atomic_dec_uint(&unp_rights); 1952 (void)closef(fp); 1953 } 1954 1955 static void 1956 unp_discard_later(file_t *fp) 1957 { 1958 1959 if (fp == NULL) 1960 return; 1961 1962 KASSERT(fp->f_count > 0); 1963 KASSERT(fp->f_msgcount > 0); 1964 1965 mutex_enter(&filelist_lock); 1966 if (fp->f_unpcount++ == 0) { 1967 SLIST_INSERT_HEAD(&unp_thread_discard, fp, f_unplist); 1968 } 1969 mutex_exit(&filelist_lock); 1970 } 1971 1972 const struct pr_usrreqs unp_usrreqs = { 1973 .pr_attach = unp_attach, 1974 .pr_detach = unp_detach, 1975 .pr_accept = unp_accept, 1976 .pr_bind = unp_bind, 1977 .pr_listen = unp_listen, 1978 .pr_connect = unp_connect, 1979 .pr_connect2 = unp_connect2, 1980 .pr_disconnect = unp_disconnect, 1981 .pr_shutdown = unp_shutdown, 1982 .pr_abort = unp_abort, 1983 .pr_ioctl = unp_ioctl, 1984 .pr_stat = unp_stat, 1985 .pr_peeraddr = unp_peeraddr, 1986 .pr_sockaddr = unp_sockaddr, 1987 .pr_rcvd = unp_rcvd, 1988 .pr_recvoob = unp_recvoob, 1989 .pr_send = unp_send, 1990 .pr_sendoob = unp_sendoob, 1991 .pr_generic = unp_usrreq, 1992 }; 1993
Indexes created Mon Sep 22 13:09:51 GMT 2025