1 /* 2 * Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_prot.c 8.6 (Berkeley) 1/21/94 39 * $FreeBSD: src/sys/kern/kern_prot.c,v 1.53.2.9 2002/03/09 05:20:26 dd Exp $ 40 * $DragonFly: src/sys/kern/kern_prot.c,v 1.26 2006/06/05 07:26:10 dillon Exp $ 41 */ 42 43 /* 44 * System calls related to processes and protection 45 */ 46 47 #include "opt_compat.h" 48 49 #include <sys/param.h> 50 #include <sys/acct.h> 51 #include <sys/systm.h> 52 #include <sys/sysproto.h> 53 #include <sys/kernel.h> 54 #include <sys/lock.h> 55 #include <sys/proc.h> 56 #include <sys/malloc.h> 57 #include <sys/pioctl.h> 58 #include <sys/resourcevar.h> 59 #include <sys/jail.h> 60 #include <sys/lockf.h> 61 #include <sys/spinlock.h> 62 63 #include <sys/thread2.h> 64 #include <sys/spinlock2.h> 65 66 static MALLOC_DEFINE(M_CRED, "cred", "credentials"); 67 68 /* 69 * NOT MP SAFE due to p_pptr access 70 */ 71 /* ARGSUSED */ 72 int 73 sys_getpid(struct getpid_args *uap) 74 { 75 struct proc *p = curproc; 76 77 uap->sysmsg_fds[0] = p->p_pid; 78 #if defined(COMPAT_43) || defined(COMPAT_SUNOS) 79 uap->sysmsg_fds[1] = p->p_pptr->p_pid; 80 #endif 81 return (0); 82 } 83 84 /* ARGSUSED */ 85 int 86 sys_getppid(struct getppid_args *uap) 87 { 88 struct proc *p = curproc; 89 90 uap->sysmsg_result = p->p_pptr->p_pid; 91 return (0); 92 } 93 94 /* 95 * Get process group ID; note that POSIX getpgrp takes no parameter 96 * 97 * MP SAFE 98 */ 99 int 100 sys_getpgrp(struct getpgrp_args *uap) 101 { 102 struct proc *p = curproc; 103 104 uap->sysmsg_result = p->p_pgrp->pg_id; 105 return (0); 106 } 107 108 /* 109 * Get an arbitary pid's process group id 110 */ 111 int 112 sys_getpgid(struct getpgid_args *uap) 113 { 114 struct proc *p = curproc; 115 struct proc *pt; 116 117 pt = p; 118 if (uap->pid == 0) 119 goto found; 120 121 if ((pt = pfind(uap->pid)) == 0) 122 return ESRCH; 123 found: 124 uap->sysmsg_result = pt->p_pgrp->pg_id; 125 return 0; 126 } 127 128 /* 129 * Get an arbitary pid's session id. 130 */ 131 int 132 sys_getsid(struct getsid_args *uap) 133 { 134 struct proc *p = curproc; 135 struct proc *pt; 136 137 pt = p; 138 if (uap->pid == 0) 139 goto found; 140 141 if ((pt = pfind(uap->pid)) == 0) 142 return ESRCH; 143 found: 144 uap->sysmsg_result = pt->p_session->s_sid; 145 return 0; 146 } 147 148 149 /* 150 * getuid() - MP SAFE 151 */ 152 /* ARGSUSED */ 153 int 154 sys_getuid(struct getuid_args *uap) 155 { 156 struct proc *p = curproc; 157 158 uap->sysmsg_fds[0] = p->p_ucred->cr_ruid; 159 #if defined(COMPAT_43) || defined(COMPAT_SUNOS) 160 uap->sysmsg_fds[1] = p->p_ucred->cr_uid; 161 #endif 162 return (0); 163 } 164 165 /* 166 * geteuid() - MP SAFE 167 */ 168 /* ARGSUSED */ 169 int 170 sys_geteuid(struct geteuid_args *uap) 171 { 172 struct proc *p = curproc; 173 174 uap->sysmsg_result = p->p_ucred->cr_uid; 175 return (0); 176 } 177 178 /* 179 * getgid() - MP SAFE 180 */ 181 /* ARGSUSED */ 182 int 183 sys_getgid(struct getgid_args *uap) 184 { 185 struct proc *p = curproc; 186 187 uap->sysmsg_fds[0] = p->p_ucred->cr_rgid; 188 #if defined(COMPAT_43) || defined(COMPAT_SUNOS) 189 uap->sysmsg_fds[1] = p->p_ucred->cr_groups[0]; 190 #endif 191 return (0); 192 } 193 194 /* 195 * Get effective group ID. The "egid" is groups[0], and could be obtained 196 * via getgroups. This syscall exists because it is somewhat painful to do 197 * correctly in a library function. 198 * 199 * MP SAFE 200 */ 201 /* ARGSUSED */ 202 int 203 sys_getegid(struct getegid_args *uap) 204 { 205 struct proc *p = curproc; 206 207 uap->sysmsg_result = p->p_ucred->cr_groups[0]; 208 return (0); 209 } 210 211 int 212 sys_getgroups(struct getgroups_args *uap) 213 { 214 struct proc *p = curproc; 215 struct ucred *cr; 216 u_int ngrp; 217 int error; 218 219 if (p == NULL) /* API enforcement */ 220 return(EPERM); 221 cr = p->p_ucred; 222 223 if ((ngrp = uap->gidsetsize) == 0) { 224 uap->sysmsg_result = cr->cr_ngroups; 225 return (0); 226 } 227 if (ngrp < cr->cr_ngroups) 228 return (EINVAL); 229 ngrp = cr->cr_ngroups; 230 if ((error = copyout((caddr_t)cr->cr_groups, 231 (caddr_t)uap->gidset, ngrp * sizeof(gid_t)))) 232 return (error); 233 uap->sysmsg_result = ngrp; 234 return (0); 235 } 236 237 /* ARGSUSED */ 238 int 239 sys_setsid(struct setsid_args *uap) 240 { 241 struct proc *p = curproc; 242 243 if (p->p_pgid == p->p_pid || pgfind(p->p_pid)) { 244 return (EPERM); 245 } else { 246 (void)enterpgrp(p, p->p_pid, 1); 247 uap->sysmsg_result = p->p_pid; 248 return (0); 249 } 250 } 251 252 /* 253 * set process group (setpgid/old setpgrp) 254 * 255 * caller does setpgid(targpid, targpgid) 256 * 257 * pid must be caller or child of caller (ESRCH) 258 * if a child 259 * pid must be in same session (EPERM) 260 * pid can't have done an exec (EACCES) 261 * if pgid != pid 262 * there must exist some pid in same session having pgid (EPERM) 263 * pid must not be session leader (EPERM) 264 */ 265 /* ARGSUSED */ 266 int 267 sys_setpgid(struct setpgid_args *uap) 268 { 269 struct proc *curp = curproc; 270 struct proc *targp; /* target process */ 271 struct pgrp *pgrp; /* target pgrp */ 272 273 if (uap->pgid < 0) 274 return (EINVAL); 275 if (uap->pid != 0 && uap->pid != curp->p_pid) { 276 if ((targp = pfind(uap->pid)) == 0 || !inferior(targp)) 277 return (ESRCH); 278 if (targp->p_pgrp == NULL || targp->p_session != curp->p_session) 279 return (EPERM); 280 if (targp->p_flag & P_EXEC) 281 return (EACCES); 282 } else 283 targp = curp; 284 if (SESS_LEADER(targp)) 285 return (EPERM); 286 if (uap->pgid == 0) 287 uap->pgid = targp->p_pid; 288 else if (uap->pgid != targp->p_pid) 289 if ((pgrp = pgfind(uap->pgid)) == 0 || 290 pgrp->pg_session != curp->p_session) 291 return (EPERM); 292 return (enterpgrp(targp, uap->pgid, 0)); 293 } 294 295 /* 296 * Use the clause in B.4.2.2 that allows setuid/setgid to be 4.2/4.3BSD 297 * compatible. It says that setting the uid/gid to euid/egid is a special 298 * case of "appropriate privilege". Once the rules are expanded out, this 299 * basically means that setuid(nnn) sets all three id's, in all permitted 300 * cases unless _POSIX_SAVED_IDS is enabled. In that case, setuid(getuid()) 301 * does not set the saved id - this is dangerous for traditional BSD 302 * programs. For this reason, we *really* do not want to set 303 * _POSIX_SAVED_IDS and do not want to clear POSIX_APPENDIX_B_4_2_2. 304 */ 305 #define POSIX_APPENDIX_B_4_2_2 306 307 /* ARGSUSED */ 308 int 309 sys_setuid(struct setuid_args *uap) 310 { 311 struct proc *p = curproc; 312 struct ucred *cr; 313 uid_t uid; 314 int error; 315 316 if (p == NULL) /* API enforcement */ 317 return(EPERM); 318 cr = p->p_ucred; 319 320 /* 321 * See if we have "permission" by POSIX 1003.1 rules. 322 * 323 * Note that setuid(geteuid()) is a special case of 324 * "appropriate privileges" in appendix B.4.2.2. We need 325 * to use this clause to be compatible with traditional BSD 326 * semantics. Basically, it means that "setuid(xx)" sets all 327 * three id's (assuming you have privs). 328 * 329 * Notes on the logic. We do things in three steps. 330 * 1: We determine if the euid is going to change, and do EPERM 331 * right away. We unconditionally change the euid later if this 332 * test is satisfied, simplifying that part of the logic. 333 * 2: We determine if the real and/or saved uid's are going to 334 * change. Determined by compile options. 335 * 3: Change euid last. (after tests in #2 for "appropriate privs") 336 */ 337 uid = uap->uid; 338 if (uid != cr->cr_ruid && /* allow setuid(getuid()) */ 339 #ifdef _POSIX_SAVED_IDS 340 uid != crc->cr_svuid && /* allow setuid(saved gid) */ 341 #endif 342 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */ 343 uid != cr->cr_uid && /* allow setuid(geteuid()) */ 344 #endif 345 (error = suser_cred(cr, PRISON_ROOT))) 346 return (error); 347 348 #ifdef _POSIX_SAVED_IDS 349 /* 350 * Do we have "appropriate privileges" (are we root or uid == euid) 351 * If so, we are changing the real uid and/or saved uid. 352 */ 353 if ( 354 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use the clause from B.4.2.2 */ 355 uid == cr->cr_uid || 356 #endif 357 suser_cred(cr, PRISON_ROOT) == 0) /* we are using privs */ 358 #endif 359 { 360 /* 361 * Set the real uid and transfer proc count to new user. 362 */ 363 if (uid != cr->cr_ruid) { 364 change_ruid(uid); 365 setsugid(); 366 } 367 /* 368 * Set saved uid 369 * 370 * XXX always set saved uid even if not _POSIX_SAVED_IDS, as 371 * the security of seteuid() depends on it. B.4.2.2 says it 372 * is important that we should do this. 373 */ 374 if (cr->cr_svuid != uid) { 375 cr = cratom(&p->p_ucred); 376 cr->cr_svuid = uid; 377 setsugid(); 378 } 379 } 380 381 /* 382 * In all permitted cases, we are changing the euid. 383 * Copy credentials so other references do not see our changes. 384 */ 385 if (cr->cr_uid != uid) { 386 change_euid(uid); 387 setsugid(); 388 } 389 return (0); 390 } 391 392 /* ARGSUSED */ 393 int 394 sys_seteuid(struct seteuid_args *uap) 395 { 396 struct proc *p = curproc; 397 struct ucred *cr; 398 uid_t euid; 399 int error; 400 401 if (p == NULL) /* API enforcement */ 402 return(EPERM); 403 404 cr = p->p_ucred; 405 euid = uap->euid; 406 if (euid != cr->cr_ruid && /* allow seteuid(getuid()) */ 407 euid != cr->cr_svuid && /* allow seteuid(saved uid) */ 408 (error = suser_cred(cr, PRISON_ROOT))) 409 return (error); 410 /* 411 * Everything's okay, do it. Copy credentials so other references do 412 * not see our changes. 413 */ 414 if (cr->cr_uid != euid) { 415 change_euid(euid); 416 setsugid(); 417 } 418 return (0); 419 } 420 421 /* ARGSUSED */ 422 int 423 sys_setgid(struct setgid_args *uap) 424 { 425 struct proc *p = curproc; 426 struct ucred *cr; 427 gid_t gid; 428 int error; 429 430 if (p == NULL) /* API enforcement */ 431 return(EPERM); 432 cr = p->p_ucred; 433 434 /* 435 * See if we have "permission" by POSIX 1003.1 rules. 436 * 437 * Note that setgid(getegid()) is a special case of 438 * "appropriate privileges" in appendix B.4.2.2. We need 439 * to use this clause to be compatible with traditional BSD 440 * semantics. Basically, it means that "setgid(xx)" sets all 441 * three id's (assuming you have privs). 442 * 443 * For notes on the logic here, see setuid() above. 444 */ 445 gid = uap->gid; 446 if (gid != cr->cr_rgid && /* allow setgid(getgid()) */ 447 #ifdef _POSIX_SAVED_IDS 448 gid != cr->cr_svgid && /* allow setgid(saved gid) */ 449 #endif 450 #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */ 451 gid != cr->cr_groups[0] && /* allow setgid(getegid()) */ 452 #endif 453 (error = suser_cred(cr, PRISON_ROOT))) 454 return (error); 455 456 #ifdef _POSIX_SAVED_IDS 457 /* 458 * Do we have "appropriate privileges" (are we root or gid == egid) 459 * If so, we are changing the real uid and saved gid. 460 */ 461 if ( 462 #ifdef POSIX_APPENDIX_B_4_2_2 /* use the clause from B.4.2.2 */ 463 gid == cr->cr_groups[0] || 464 #endif 465 suser_cred(cr, PRISON_ROOT) == 0) /* we are using privs */ 466 #endif 467 { 468 /* 469 * Set real gid 470 */ 471 if (cr->cr_rgid != gid) { 472 cr = cratom(&p->p_ucred); 473 cr->cr_rgid = gid; 474 setsugid(); 475 } 476 /* 477 * Set saved gid 478 * 479 * XXX always set saved gid even if not _POSIX_SAVED_IDS, as 480 * the security of setegid() depends on it. B.4.2.2 says it 481 * is important that we should do this. 482 */ 483 if (cr->cr_svgid != gid) { 484 cr = cratom(&p->p_ucred); 485 cr->cr_svgid = gid; 486 setsugid(); 487 } 488 } 489 /* 490 * In all cases permitted cases, we are changing the egid. 491 * Copy credentials so other references do not see our changes. 492 */ 493 if (cr->cr_groups[0] != gid) { 494 cr = cratom(&p->p_ucred); 495 cr->cr_groups[0] = gid; 496 setsugid(); 497 } 498 return (0); 499 } 500 501 /* ARGSUSED */ 502 int 503 sys_setegid(struct setegid_args *uap) 504 { 505 struct proc *p = curproc; 506 struct ucred *cr; 507 gid_t egid; 508 int error; 509 510 if (p == NULL) /* API enforcement */ 511 return(EPERM); 512 cr = p->p_ucred; 513 514 egid = uap->egid; 515 if (egid != cr->cr_rgid && /* allow setegid(getgid()) */ 516 egid != cr->cr_svgid && /* allow setegid(saved gid) */ 517 (error = suser_cred(cr, PRISON_ROOT))) 518 return (error); 519 if (cr->cr_groups[0] != egid) { 520 cr = cratom(&p->p_ucred); 521 cr->cr_groups[0] = egid; 522 setsugid(); 523 } 524 return (0); 525 } 526 527 /* ARGSUSED */ 528 int 529 sys_setgroups(struct setgroups_args *uap) 530 { 531 struct proc *p = curproc; 532 struct ucred *cr; 533 u_int ngrp; 534 int error; 535 536 if (p == NULL) /* API enforcement */ 537 return(EPERM); 538 cr = p->p_ucred; 539 540 if ((error = suser_cred(cr, PRISON_ROOT))) 541 return (error); 542 ngrp = uap->gidsetsize; 543 if (ngrp > NGROUPS) 544 return (EINVAL); 545 /* 546 * XXX A little bit lazy here. We could test if anything has 547 * changed before cratom() and setting P_SUGID. 548 */ 549 cr = cratom(&p->p_ucred); 550 if (ngrp < 1) { 551 /* 552 * setgroups(0, NULL) is a legitimate way of clearing the 553 * groups vector on non-BSD systems (which generally do not 554 * have the egid in the groups[0]). We risk security holes 555 * when running non-BSD software if we do not do the same. 556 */ 557 cr->cr_ngroups = 1; 558 } else { 559 if ((error = copyin((caddr_t)uap->gidset, 560 (caddr_t)cr->cr_groups, ngrp * sizeof(gid_t)))) 561 return (error); 562 cr->cr_ngroups = ngrp; 563 } 564 setsugid(); 565 return (0); 566 } 567 568 /* ARGSUSED */ 569 int 570 sys_setreuid(struct setreuid_args *uap) 571 { 572 struct proc *p = curproc; 573 struct ucred *cr; 574 uid_t ruid, euid; 575 int error; 576 577 if (p == NULL) /* API enforcement */ 578 return(EPERM); 579 cr = p->p_ucred; 580 581 ruid = uap->ruid; 582 euid = uap->euid; 583 if (((ruid != (uid_t)-1 && ruid != cr->cr_ruid && ruid != cr->cr_svuid) || 584 (euid != (uid_t)-1 && euid != cr->cr_uid && 585 euid != cr->cr_ruid && euid != cr->cr_svuid)) && 586 (error = suser_cred(cr, PRISON_ROOT)) != 0) 587 return (error); 588 589 if (euid != (uid_t)-1 && cr->cr_uid != euid) { 590 change_euid(euid); 591 setsugid(); 592 } 593 if (ruid != (uid_t)-1 && cr->cr_ruid != ruid) { 594 change_ruid(ruid); 595 setsugid(); 596 } 597 if ((ruid != (uid_t)-1 || cr->cr_uid != cr->cr_ruid) && 598 cr->cr_svuid != cr->cr_uid) { 599 cr = cratom(&p->p_ucred); 600 cr->cr_svuid = cr->cr_uid; 601 setsugid(); 602 } 603 return (0); 604 } 605 606 /* ARGSUSED */ 607 int 608 sys_setregid(struct setregid_args *uap) 609 { 610 struct proc *p = curproc; 611 struct ucred *cr; 612 gid_t rgid, egid; 613 int error; 614 615 if (p == NULL) /* API enforcement */ 616 return(EPERM); 617 cr = p->p_ucred; 618 619 rgid = uap->rgid; 620 egid = uap->egid; 621 if (((rgid != (gid_t)-1 && rgid != cr->cr_rgid && rgid != cr->cr_svgid) || 622 (egid != (gid_t)-1 && egid != cr->cr_groups[0] && 623 egid != cr->cr_rgid && egid != cr->cr_svgid)) && 624 (error = suser_cred(cr, PRISON_ROOT)) != 0) 625 return (error); 626 627 if (egid != (gid_t)-1 && cr->cr_groups[0] != egid) { 628 cr = cratom(&p->p_ucred); 629 cr->cr_groups[0] = egid; 630 setsugid(); 631 } 632 if (rgid != (gid_t)-1 && cr->cr_rgid != rgid) { 633 cr = cratom(&p->p_ucred); 634 cr->cr_rgid = rgid; 635 setsugid(); 636 } 637 if ((rgid != (gid_t)-1 || cr->cr_groups[0] != cr->cr_rgid) && 638 cr->cr_svgid != cr->cr_groups[0]) { 639 cr = cratom(&p->p_ucred); 640 cr->cr_svgid = cr->cr_groups[0]; 641 setsugid(); 642 } 643 return (0); 644 } 645 646 /* 647 * setresuid(ruid, euid, suid) is like setreuid except control over the 648 * saved uid is explicit. 649 */ 650 651 /* ARGSUSED */ 652 int 653 sys_setresuid(struct setresuid_args *uap) 654 { 655 struct proc *p = curproc; 656 struct ucred *cr; 657 uid_t ruid, euid, suid; 658 int error; 659 660 cr = p->p_ucred; 661 ruid = uap->ruid; 662 euid = uap->euid; 663 suid = uap->suid; 664 if (((ruid != (uid_t)-1 && ruid != cr->cr_ruid && ruid != cr->cr_svuid && 665 ruid != cr->cr_uid) || 666 (euid != (uid_t)-1 && euid != cr->cr_ruid && euid != cr->cr_svuid && 667 euid != cr->cr_uid) || 668 (suid != (uid_t)-1 && suid != cr->cr_ruid && suid != cr->cr_svuid && 669 suid != cr->cr_uid)) && 670 (error = suser_cred(cr, PRISON_ROOT)) != 0) 671 return (error); 672 if (euid != (uid_t)-1 && cr->cr_uid != euid) { 673 change_euid(euid); 674 setsugid(); 675 } 676 if (ruid != (uid_t)-1 && cr->cr_ruid != ruid) { 677 change_ruid(ruid); 678 setsugid(); 679 } 680 if (suid != (uid_t)-1 && cr->cr_svuid != suid) { 681 cr = cratom(&p->p_ucred); 682 cr->cr_svuid = suid; 683 setsugid(); 684 } 685 return (0); 686 } 687 688 /* 689 * setresgid(rgid, egid, sgid) is like setregid except control over the 690 * saved gid is explicit. 691 */ 692 693 /* ARGSUSED */ 694 int 695 sys_setresgid(struct setresgid_args *uap) 696 { 697 struct proc *p = curproc; 698 struct ucred *cr; 699 gid_t rgid, egid, sgid; 700 int error; 701 702 cr = p->p_ucred; 703 rgid = uap->rgid; 704 egid = uap->egid; 705 sgid = uap->sgid; 706 if (((rgid != (gid_t)-1 && rgid != cr->cr_rgid && rgid != cr->cr_svgid && 707 rgid != cr->cr_groups[0]) || 708 (egid != (gid_t)-1 && egid != cr->cr_rgid && egid != cr->cr_svgid && 709 egid != cr->cr_groups[0]) || 710 (sgid != (gid_t)-1 && sgid != cr->cr_rgid && sgid != cr->cr_svgid && 711 sgid != cr->cr_groups[0])) && 712 (error = suser_cred(cr, PRISON_ROOT)) != 0) 713 return (error); 714 715 if (egid != (gid_t)-1 && cr->cr_groups[0] != egid) { 716 cr = cratom(&p->p_ucred); 717 cr->cr_groups[0] = egid; 718 setsugid(); 719 } 720 if (rgid != (gid_t)-1 && cr->cr_rgid != rgid) { 721 cr = cratom(&p->p_ucred); 722 cr->cr_rgid = rgid; 723 setsugid(); 724 } 725 if (sgid != (gid_t)-1 && cr->cr_svgid != sgid) { 726 cr = cratom(&p->p_ucred); 727 cr->cr_svgid = sgid; 728 setsugid(); 729 } 730 return (0); 731 } 732 733 /* ARGSUSED */ 734 int 735 sys_getresuid(struct getresuid_args *uap) 736 { 737 struct proc *p = curproc; 738 struct ucred *cr = p->p_ucred; 739 int error1 = 0, error2 = 0, error3 = 0; 740 741 if (uap->ruid) 742 error1 = copyout((caddr_t)&cr->cr_ruid, 743 (caddr_t)uap->ruid, sizeof(cr->cr_ruid)); 744 if (uap->euid) 745 error2 = copyout((caddr_t)&cr->cr_uid, 746 (caddr_t)uap->euid, sizeof(cr->cr_uid)); 747 if (uap->suid) 748 error3 = copyout((caddr_t)&cr->cr_svuid, 749 (caddr_t)uap->suid, sizeof(cr->cr_svuid)); 750 return error1 ? error1 : (error2 ? error2 : error3); 751 } 752 753 /* ARGSUSED */ 754 int 755 sys_getresgid(struct getresgid_args *uap) 756 { 757 struct proc *p = curproc; 758 struct ucred *cr = p->p_ucred; 759 int error1 = 0, error2 = 0, error3 = 0; 760 761 if (uap->rgid) 762 error1 = copyout((caddr_t)&cr->cr_rgid, 763 (caddr_t)uap->rgid, sizeof(cr->cr_rgid)); 764 if (uap->egid) 765 error2 = copyout((caddr_t)&cr->cr_groups[0], 766 (caddr_t)uap->egid, sizeof(cr->cr_groups[0])); 767 if (uap->sgid) 768 error3 = copyout((caddr_t)&cr->cr_svgid, 769 (caddr_t)uap->sgid, sizeof(cr->cr_svgid)); 770 return error1 ? error1 : (error2 ? error2 : error3); 771 } 772 773 774 /* ARGSUSED */ 775 int 776 sys_issetugid(struct issetugid_args *uap) 777 { 778 struct proc *p = curproc; 779 /* 780 * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time, 781 * we use P_SUGID because we consider changing the owners as 782 * "tainting" as well. 783 * This is significant for procs that start as root and "become" 784 * a user without an exec - programs cannot know *everything* 785 * that libc *might* have put in their data segment. 786 */ 787 uap->sysmsg_result = (p->p_flag & P_SUGID) ? 1 : 0; 788 return (0); 789 } 790 791 /* 792 * Check if gid is a member of the group set. 793 */ 794 int 795 groupmember(gid_t gid, struct ucred *cred) 796 { 797 gid_t *gp; 798 gid_t *egp; 799 800 egp = &(cred->cr_groups[cred->cr_ngroups]); 801 for (gp = cred->cr_groups; gp < egp; gp++) { 802 if (*gp == gid) 803 return (1); 804 } 805 return (0); 806 } 807 808 /* 809 * Test whether the specified credentials imply "super-user" 810 * privilege; if so, and we have accounting info, set the flag 811 * indicating use of super-powers. A kernel thread without a process 812 * context is assumed to have super user capabilities. In situations 813 * where the caller always expect a cred to exist, the cred should be 814 * passed separately and suser_cred()should be used instead of suser(). 815 * 816 * Returns 0 or error. 817 */ 818 int 819 suser(struct thread *td) 820 { 821 struct proc *p = td->td_proc; 822 823 if (p != NULL) { 824 return suser_cred(p->p_ucred, 0); 825 } else { 826 return (0); 827 } 828 } 829 830 /* 831 * A non-null credential is expected unless NULL_CRED_OKAY is set. 832 */ 833 int 834 suser_cred(struct ucred *cred, int flag) 835 { 836 KASSERT(cred != NULL || flag & NULL_CRED_OKAY, 837 ("suser_cred: NULL cred!")); 838 839 if (cred == NULL) { 840 if (flag & NULL_CRED_OKAY) 841 return (0); 842 else 843 return (EPERM); 844 } 845 if (cred->cr_uid != 0) 846 return (EPERM); 847 if (cred->cr_prison && !(flag & PRISON_ROOT)) 848 return (EPERM); 849 /* NOTE: accounting for suser access (p_acflag/ASU) removed */ 850 return (0); 851 } 852 853 /* 854 * Return zero if p1 can fondle p2, return errno (EPERM/ESRCH) otherwise. 855 */ 856 int 857 p_trespass(struct ucred *cr1, struct ucred *cr2) 858 { 859 if (cr1 == cr2) 860 return (0); 861 if (!PRISON_CHECK(cr1, cr2)) 862 return (ESRCH); 863 if (cr1->cr_ruid == cr2->cr_ruid) 864 return (0); 865 if (cr1->cr_uid == cr2->cr_ruid) 866 return (0); 867 if (cr1->cr_ruid == cr2->cr_uid) 868 return (0); 869 if (cr1->cr_uid == cr2->cr_uid) 870 return (0); 871 if (suser_cred(cr1, PRISON_ROOT) == 0) 872 return (0); 873 return (EPERM); 874 } 875 876 /* 877 * MPSAFE 878 */ 879 static __inline void 880 _crinit(struct ucred *cr) 881 { 882 bzero(cr, sizeof(*cr)); 883 cr->cr_ref = 1; 884 spin_init(&cr->cr_spin); 885 } 886 887 /* 888 * MPSAFE 889 */ 890 void 891 crinit(struct ucred *cr) 892 { 893 _crinit(cr); 894 } 895 896 /* 897 * Allocate a zeroed cred structure. 898 * 899 * MPSAFE 900 */ 901 struct ucred * 902 crget(void) 903 { 904 struct ucred *cr; 905 906 MALLOC(cr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK); 907 _crinit(cr); 908 return (cr); 909 } 910 911 /* 912 * Claim another reference to a ucred structure. Can be used with special 913 * creds. 914 * 915 * It must be possible to call this routine with spinlocks held, meaning 916 * that this routine itself cannot obtain a spinlock. 917 * 918 * MPSAFE 919 */ 920 struct ucred * 921 crhold(struct ucred *cr) 922 { 923 if (cr != NOCRED && cr != FSCRED) 924 atomic_add_int(&cr->cr_ref, 1); 925 return(cr); 926 } 927 928 /* 929 * Drop a reference from the cred structure, free it if the reference count 930 * reaches 0. 931 * 932 * NOTE: because we used atomic_add_int() above, without a spinlock, we 933 * must also use atomic_subtract_int() below. A spinlock is required 934 * in crfree() to handle multiple callers racing the refcount to 0. 935 * 936 * MPALMOSTSAFE - acquires mplock on 1->0 transition of ref count 937 */ 938 void 939 crfree(struct ucred *cr) 940 { 941 if (cr->cr_ref <= 0) 942 panic("Freeing already free credential! %p", cr); 943 spin_lock_wr(&cr->cr_spin); 944 atomic_subtract_int(&cr->cr_ref, 1); 945 if (cr->cr_ref == 0) { 946 spin_unlock_wr(&cr->cr_spin); 947 /* 948 * Some callers of crget(), such as nfs_statfs(), 949 * allocate a temporary credential, but don't 950 * allocate a uidinfo structure. 951 */ 952 get_mplock(); 953 if (cr->cr_uidinfo != NULL) { 954 uidrop(cr->cr_uidinfo); 955 cr->cr_uidinfo = NULL; 956 } 957 if (cr->cr_ruidinfo != NULL) { 958 uidrop(cr->cr_ruidinfo); 959 cr->cr_ruidinfo = NULL; 960 } 961 962 /* 963 * Destroy empty prisons 964 */ 965 if (jailed(cr)) 966 prison_free(cr->cr_prison); 967 cr->cr_prison = NULL; /* safety */ 968 969 FREE((caddr_t)cr, M_CRED); 970 rel_mplock(); 971 } else { 972 spin_unlock_wr(&cr->cr_spin); 973 } 974 } 975 976 /* 977 * Atomize a cred structure so it can be modified without polluting 978 * other references to it. 979 */ 980 struct ucred * 981 cratom(struct ucred **pcr) 982 { 983 struct ucred *oldcr; 984 struct ucred *newcr; 985 986 oldcr = *pcr; 987 if (oldcr->cr_ref == 1) 988 return (oldcr); 989 newcr = crget(); 990 *newcr = *oldcr; 991 if (newcr->cr_uidinfo) 992 uihold(newcr->cr_uidinfo); 993 if (newcr->cr_ruidinfo) 994 uihold(newcr->cr_ruidinfo); 995 if (jailed(newcr)) 996 prison_hold(newcr->cr_prison); 997 newcr->cr_ref = 1; 998 crfree(oldcr); 999 *pcr = newcr; 1000 return (newcr); 1001 } 1002 1003 #if 0 /* no longer used but keep around for a little while */ 1004 /* 1005 * Copy cred structure to a new one and free the old one. 1006 */ 1007 struct ucred * 1008 crcopy(struct ucred *cr) 1009 { 1010 struct ucred *newcr; 1011 1012 if (cr->cr_ref == 1) 1013 return (cr); 1014 newcr = crget(); 1015 *newcr = *cr; 1016 if (newcr->cr_uidinfo) 1017 uihold(newcr->cr_uidinfo); 1018 if (newcr->cr_ruidinfo) 1019 uihold(newcr->cr_ruidinfo); 1020 if (jailed(newcr)) 1021 prison_hold(newcr->cr_prison); 1022 newcr->cr_ref = 1; 1023 crfree(cr); 1024 return (newcr); 1025 } 1026 #endif 1027 1028 /* 1029 * Dup cred struct to a new held one. 1030 */ 1031 struct ucred * 1032 crdup(struct ucred *cr) 1033 { 1034 struct ucred *newcr; 1035 1036 newcr = crget(); 1037 *newcr = *cr; 1038 if (newcr->cr_uidinfo) 1039 uihold(newcr->cr_uidinfo); 1040 if (newcr->cr_ruidinfo) 1041 uihold(newcr->cr_ruidinfo); 1042 if (jailed(newcr)) 1043 prison_hold(newcr->cr_prison); 1044 newcr->cr_ref = 1; 1045 return (newcr); 1046 } 1047 1048 /* 1049 * Fill in a struct xucred based on a struct ucred. 1050 */ 1051 void 1052 cru2x(struct ucred *cr, struct xucred *xcr) 1053 { 1054 1055 bzero(xcr, sizeof(*xcr)); 1056 xcr->cr_version = XUCRED_VERSION; 1057 xcr->cr_uid = cr->cr_uid; 1058 xcr->cr_ngroups = cr->cr_ngroups; 1059 bcopy(cr->cr_groups, xcr->cr_groups, sizeof(cr->cr_groups)); 1060 } 1061 1062 /* 1063 * Get login name, if available. 1064 */ 1065 /* ARGSUSED */ 1066 int 1067 sys_getlogin(struct getlogin_args *uap) 1068 { 1069 struct proc *p = curproc; 1070 1071 if (uap->namelen > MAXLOGNAME) 1072 uap->namelen = MAXLOGNAME; 1073 return (copyout((caddr_t) p->p_pgrp->pg_session->s_login, 1074 (caddr_t) uap->namebuf, uap->namelen)); 1075 } 1076 1077 /* 1078 * Set login name. 1079 */ 1080 /* ARGSUSED */ 1081 int 1082 sys_setlogin(struct setlogin_args *uap) 1083 { 1084 struct proc *p = curproc; 1085 int error; 1086 char logintmp[MAXLOGNAME]; 1087 1088 KKASSERT(p != NULL); 1089 if ((error = suser_cred(p->p_ucred, PRISON_ROOT))) 1090 return (error); 1091 error = copyinstr((caddr_t) uap->namebuf, (caddr_t) logintmp, 1092 sizeof(logintmp), (size_t *)0); 1093 if (error == ENAMETOOLONG) 1094 error = EINVAL; 1095 else if (!error) 1096 (void) memcpy(p->p_pgrp->pg_session->s_login, logintmp, 1097 sizeof(logintmp)); 1098 return (error); 1099 } 1100 1101 void 1102 setsugid(void) 1103 { 1104 struct proc *p = curproc; 1105 1106 KKASSERT(p != NULL); 1107 p->p_flag |= P_SUGID; 1108 if (!(p->p_pfsflags & PF_ISUGID)) 1109 p->p_stops = 0; 1110 } 1111 1112 /* 1113 * Helper function to change the effective uid of a process 1114 */ 1115 void 1116 change_euid(uid_t euid) 1117 { 1118 struct proc *p = curproc; 1119 struct ucred *cr; 1120 1121 KKASSERT(p != NULL); 1122 lf_count_adjust(p, 0); 1123 cr = cratom(&p->p_ucred); 1124 cr->cr_uid = euid; 1125 uireplace(&cr->cr_uidinfo, uifind(euid)); 1126 lf_count_adjust(p, 1); 1127 } 1128 1129 /* 1130 * Helper function to change the real uid of a process 1131 * 1132 * The per-uid process count for this process is transfered from 1133 * the old uid to the new uid. 1134 */ 1135 void 1136 change_ruid(uid_t ruid) 1137 { 1138 struct proc *p = curproc; 1139 struct ucred *cr; 1140 1141 KKASSERT(p != NULL); 1142 1143 cr = cratom(&p->p_ucred); 1144 (void)chgproccnt(cr->cr_ruidinfo, -1, 0); 1145 /* It is assumed that pcred is not shared between processes */ 1146 cr->cr_ruid = ruid; 1147 uireplace(&cr->cr_ruidinfo, uifind(ruid)); 1148 (void)chgproccnt(cr->cr_ruidinfo, 1, 0); 1149 } 1150