kern_prot.c revision 1.58
1 /* $NetBSD: kern_prot.c,v 1.58 2000/05/27 00:40:46 sommerfeld Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)kern_prot.c 8.9 (Berkeley) 2/14/95 41 */ 42 43 /* 44 * System calls related to processes and protection 45 */ 46 47 #include "opt_compat_freebsd.h" 48 #include "opt_compat_ibcs2.h" 49 #include "opt_compat_sunos.h" 50 #include "opt_compat_linux.h" 51 #include "opt_compat_43.h" 52 #include "opt_compat_osf1.h" 53 54 #include <sys/param.h> 55 #include <sys/acct.h> 56 #include <sys/systm.h> 57 #include <sys/ucred.h> 58 #include <sys/proc.h> 59 #include <sys/timeb.h> 60 #include <sys/times.h> 61 #include <sys/malloc.h> 62 63 #include <sys/mount.h> 64 #include <sys/syscallargs.h> 65 66 /* ARGSUSED */ 67 int 68 sys_getpid(p, v, retval) 69 struct proc *p; 70 void *v; 71 register_t *retval; 72 { 73 74 *retval = p->p_pid; 75 #if defined(COMPAT_43) || defined(COMPAT_SUNOS) || defined(COMPAT_IBCS2) || \ 76 defined(COMPAT_FREEBSD) || defined(COMPAT_OSF1) || \ 77 (defined(COMPAT_LINUX) && defined(__alpha__)) 78 retval[1] = p->p_pptr->p_pid; 79 #endif 80 return (0); 81 } 82 83 /* ARGSUSED */ 84 int 85 sys_getppid(p, v, retval) 86 struct proc *p; 87 void *v; 88 register_t *retval; 89 { 90 91 *retval = p->p_pptr->p_pid; 92 return (0); 93 } 94 95 /* Get process group ID; note that POSIX getpgrp takes no parameter */ 96 int 97 sys_getpgrp(p, v, retval) 98 struct proc *p; 99 void *v; 100 register_t *retval; 101 { 102 103 *retval = p->p_pgrp->pg_id; 104 return (0); 105 } 106 107 /* 108 * Return the process group ID of the session leader (session ID) 109 * for the specified process. 110 */ 111 int 112 sys_getsid(p, v, retval) 113 struct proc *p; 114 void *v; 115 register_t *retval; 116 { 117 struct sys_getsid_args /* { 118 syscalldarg(pid_t) pid; 119 } */ *uap = v; 120 121 if (SCARG(uap, pid) == 0) 122 goto found; 123 if ((p = pfind(SCARG(uap, pid))) == 0) 124 return (ESRCH); 125 found: 126 *retval = p->p_session->s_sid; 127 return 0; 128 } 129 130 int 131 sys_getpgid(p, v, retval) 132 struct proc *p; 133 void *v; 134 register_t *retval; 135 { 136 struct sys_getpgid_args /* { 137 syscallarg(pid_t) pid; 138 } */ *uap = v; 139 140 if (SCARG(uap, pid) == 0) 141 goto found; 142 if ((p = pfind(SCARG(uap, pid))) == 0) 143 return (ESRCH); 144 found: 145 *retval = p->p_pgid; 146 return 0; 147 } 148 149 /* ARGSUSED */ 150 int 151 sys_getuid(p, v, retval) 152 struct proc *p; 153 void *v; 154 register_t *retval; 155 { 156 157 *retval = p->p_cred->p_ruid; 158 #if defined(COMPAT_43) || defined(COMPAT_SUNOS) || defined(COMPAT_IBCS2) || \ 159 defined(COMPAT_FREEBSD) || defined(COMPAT_OSF1) || \ 160 (defined(COMPAT_LINUX) && defined(__alpha__)) 161 retval[1] = p->p_ucred->cr_uid; 162 #endif 163 return (0); 164 } 165 166 /* ARGSUSED */ 167 int 168 sys_geteuid(p, v, retval) 169 struct proc *p; 170 void *v; 171 register_t *retval; 172 { 173 174 *retval = p->p_ucred->cr_uid; 175 return (0); 176 } 177 178 /* ARGSUSED */ 179 int 180 sys_getgid(p, v, retval) 181 struct proc *p; 182 void *v; 183 register_t *retval; 184 { 185 186 *retval = p->p_cred->p_rgid; 187 #if defined(COMPAT_43) || defined(COMPAT_SUNOS) || defined(COMPAT_FREEBSD) || \ 188 defined(COMPAT_OSF1) || (defined(COMPAT_LINUX) && defined(alpha)) 189 retval[1] = p->p_ucred->cr_gid; 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 /* ARGSUSED */ 200 int 201 sys_getegid(p, v, retval) 202 struct proc *p; 203 void *v; 204 register_t *retval; 205 { 206 207 *retval = p->p_ucred->cr_gid; 208 return (0); 209 } 210 211 int 212 sys_getgroups(p, v, retval) 213 struct proc *p; 214 void *v; 215 register_t *retval; 216 { 217 struct sys_getgroups_args /* { 218 syscallarg(int) gidsetsize; 219 syscallarg(gid_t *) gidset; 220 } */ *uap = v; 221 struct pcred *pc = p->p_cred; 222 int ngrp; 223 int error; 224 225 ngrp = SCARG(uap, gidsetsize); 226 if (ngrp == 0) { 227 *retval = pc->pc_ucred->cr_ngroups; 228 return (0); 229 } 230 if (ngrp < pc->pc_ucred->cr_ngroups) 231 return (EINVAL); 232 ngrp = pc->pc_ucred->cr_ngroups; 233 error = copyout((caddr_t)pc->pc_ucred->cr_groups, 234 (caddr_t)SCARG(uap, gidset), ngrp * sizeof(gid_t)); 235 if (error) 236 return (error); 237 *retval = ngrp; 238 return (0); 239 } 240 241 /* ARGSUSED */ 242 int 243 sys_setsid(p, v, retval) 244 struct proc *p; 245 void *v; 246 register_t *retval; 247 { 248 249 if (p->p_pgid == p->p_pid || pgfind(p->p_pid)) { 250 return (EPERM); 251 } else { 252 (void)enterpgrp(p, p->p_pid, 1); 253 *retval = p->p_pid; 254 return (0); 255 } 256 } 257 258 /* 259 * set process group (setpgid/old setpgrp) 260 * 261 * caller does setpgid(targpid, targpgid) 262 * 263 * pgid must be in valid range (EINVAL) 264 * pid must be caller or child of caller (ESRCH) 265 * if a child 266 * pid must be in same session (EPERM) 267 * pid can't have done an exec (EACCES) 268 * if pgid != pid 269 * there must exist some pid in same session having pgid (EPERM) 270 * pid must not be session leader (EPERM) 271 */ 272 /* ARGSUSED */ 273 int 274 sys_setpgid(curp, v, retval) 275 struct proc *curp; 276 void *v; 277 register_t *retval; 278 { 279 struct sys_setpgid_args /* { 280 syscallarg(int) pid; 281 syscallarg(int) pgid; 282 } */ *uap = v; 283 struct proc *targp; /* target process */ 284 struct pgrp *pgrp; /* target pgrp */ 285 286 if (SCARG(uap, pgid) < 0) 287 return (EINVAL); 288 289 if (SCARG(uap, pid) != 0 && SCARG(uap, pid) != curp->p_pid) { 290 if ((targp = pfind(SCARG(uap, pid))) == 0 291 || !inferior(targp, curp)) 292 return (ESRCH); 293 if (targp->p_session != curp->p_session) 294 return (EPERM); 295 if (targp->p_flag & P_EXEC) 296 return (EACCES); 297 } else 298 targp = curp; 299 if (SESS_LEADER(targp)) 300 return (EPERM); 301 if (SCARG(uap, pgid) == 0) 302 SCARG(uap, pgid) = targp->p_pid; 303 else if (SCARG(uap, pgid) != targp->p_pid) 304 if ((pgrp = pgfind(SCARG(uap, pgid))) == 0 || 305 pgrp->pg_session != curp->p_session) 306 return (EPERM); 307 return (enterpgrp(targp, SCARG(uap, pgid), 0)); 308 } 309 310 /* ARGSUSED */ 311 int 312 sys_setuid(p, v, retval) 313 struct proc *p; 314 void *v; 315 register_t *retval; 316 { 317 struct sys_setuid_args /* { 318 syscallarg(uid_t) uid; 319 } */ *uap = v; 320 struct pcred *pc = p->p_cred; 321 uid_t uid; 322 int error; 323 324 uid = SCARG(uap, uid); 325 if (uid != pc->p_ruid && 326 (error = suser(pc->pc_ucred, &p->p_acflag))) 327 return (error); 328 /* 329 * Everything's okay, do it. 330 * Transfer proc count to new user. 331 * Copy credentials so other references do not see our changes. 332 */ 333 (void)chgproccnt(pc->p_ruid, -1); 334 (void)chgproccnt(uid, 1); 335 pc->pc_ucred = crcopy(pc->pc_ucred); 336 pc->pc_ucred->cr_uid = uid; 337 pc->p_ruid = uid; 338 pc->p_svuid = uid; 339 p_sugid(p); 340 return (0); 341 } 342 343 /* ARGSUSED */ 344 int 345 sys_seteuid(p, v, retval) 346 struct proc *p; 347 void *v; 348 register_t *retval; 349 { 350 struct sys_seteuid_args /* { 351 syscallarg(uid_t) euid; 352 } */ *uap = v; 353 struct pcred *pc = p->p_cred; 354 uid_t euid; 355 int error; 356 357 euid = SCARG(uap, euid); 358 if (euid != pc->p_ruid && euid != pc->p_svuid && 359 (error = suser(pc->pc_ucred, &p->p_acflag))) 360 return (error); 361 /* 362 * Everything's okay, do it. Copy credentials so other references do 363 * not see our changes. 364 */ 365 pc->pc_ucred = crcopy(pc->pc_ucred); 366 pc->pc_ucred->cr_uid = euid; 367 p_sugid(p); 368 return (0); 369 } 370 371 int 372 sys_setreuid(p, v, retval) 373 struct proc *p; 374 void *v; 375 register_t *retval; 376 { 377 struct sys_setreuid_args /* { 378 syscallarg(uid_t) ruid; 379 syscallarg(uid_t) euid; 380 } */ *uap = v; 381 struct pcred *pc = p->p_cred; 382 uid_t ruid, euid; 383 int error; 384 385 ruid = SCARG(uap, ruid); 386 euid = SCARG(uap, euid); 387 388 if (ruid != (uid_t)-1 && 389 ruid != pc->p_ruid && ruid != pc->pc_ucred->cr_uid && 390 (error = suser(pc->pc_ucred, &p->p_acflag))) 391 return (error); 392 393 if (euid != (uid_t)-1 && 394 euid != pc->p_ruid && euid != pc->pc_ucred->cr_uid && 395 euid != pc->p_svuid && 396 (error = suser(pc->pc_ucred, &p->p_acflag))) 397 return (error); 398 399 if (euid != (uid_t)-1) { 400 pc->pc_ucred = crcopy(pc->pc_ucred); 401 pc->pc_ucred->cr_uid = euid; 402 } 403 404 if (ruid != (uid_t)-1) { 405 (void)chgproccnt(pc->p_ruid, -1); 406 (void)chgproccnt(ruid, 1); 407 pc->p_ruid = ruid; 408 pc->p_svuid = pc->pc_ucred->cr_uid; 409 } 410 411 if (euid != (uid_t)-1 && ruid != (uid_t)-1) 412 p_sugid(p); 413 return (0); 414 } 415 416 /* ARGSUSED */ 417 int 418 sys_setgid(p, v, retval) 419 struct proc *p; 420 void *v; 421 register_t *retval; 422 { 423 struct sys_setgid_args /* { 424 syscallarg(gid_t) gid; 425 } */ *uap = v; 426 struct pcred *pc = p->p_cred; 427 gid_t gid; 428 int error; 429 430 gid = SCARG(uap, gid); 431 if (gid != pc->p_rgid && 432 (error = suser(pc->pc_ucred, &p->p_acflag))) 433 return (error); 434 pc->pc_ucred = crcopy(pc->pc_ucred); 435 pc->pc_ucred->cr_gid = gid; 436 pc->p_rgid = gid; 437 pc->p_svgid = gid; 438 p_sugid(p); 439 return (0); 440 } 441 442 /* ARGSUSED */ 443 int 444 sys_setegid(p, v, retval) 445 struct proc *p; 446 void *v; 447 register_t *retval; 448 { 449 struct sys_setegid_args /* { 450 syscallarg(gid_t) egid; 451 } */ *uap = v; 452 struct pcred *pc = p->p_cred; 453 gid_t egid; 454 int error; 455 456 egid = SCARG(uap, egid); 457 if (egid != pc->p_rgid && egid != pc->p_svgid && 458 (error = suser(pc->pc_ucred, &p->p_acflag))) 459 return (error); 460 pc->pc_ucred = crcopy(pc->pc_ucred); 461 pc->pc_ucred->cr_gid = egid; 462 p_sugid(p); 463 return (0); 464 } 465 466 int 467 sys_setregid(p, v, retval) 468 struct proc *p; 469 void *v; 470 register_t *retval; 471 { 472 struct sys_setregid_args /* { 473 syscallarg(gid_t) rgid; 474 syscallarg(gid_t) egid; 475 } */ *uap = v; 476 struct pcred *pc = p->p_cred; 477 gid_t rgid, egid; 478 int error; 479 480 rgid = SCARG(uap, rgid); 481 egid = SCARG(uap, egid); 482 483 if (rgid != (gid_t)-1 && 484 rgid != pc->p_rgid && rgid != pc->pc_ucred->cr_gid && 485 (error = suser(pc->pc_ucred, &p->p_acflag))) 486 return (error); 487 488 if (egid != (gid_t)-1 && 489 egid != pc->p_rgid && egid != pc->pc_ucred->cr_gid && 490 egid != pc->p_svgid && 491 (error = suser(pc->pc_ucred, &p->p_acflag))) 492 return (error); 493 494 if (egid != (gid_t)-1) { 495 pc->pc_ucred = crcopy(pc->pc_ucred); 496 pc->pc_ucred->cr_gid = egid; 497 } 498 499 if (rgid != (gid_t)-1) { 500 pc->p_rgid = rgid; 501 pc->p_svgid = pc->pc_ucred->cr_gid; 502 } 503 504 if (egid != (gid_t)-1 && rgid != (gid_t)-1) 505 p_sugid(p); 506 return (0); 507 } 508 509 int 510 sys_issetugid(p, v, retval) 511 struct proc *p; 512 void *v; 513 register_t *retval; 514 { 515 /* 516 * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time, 517 * we use P_SUGID because we consider changing the owners as 518 * "tainting" as well. 519 * This is significant for procs that start as root and "become" 520 * a user without an exec - programs cannot know *everything* 521 * that libc *might* have put in their data segment. 522 */ 523 *retval = (p->p_flag & P_SUGID) != 0; 524 return 0; 525 } 526 527 /* ARGSUSED */ 528 int 529 sys_setgroups(p, v, retval) 530 struct proc *p; 531 void *v; 532 register_t *retval; 533 { 534 struct sys_setgroups_args /* { 535 syscallarg(int) gidsetsize; 536 syscallarg(const gid_t *) gidset; 537 } */ *uap = v; 538 struct pcred *pc = p->p_cred; 539 int ngrp; 540 int error; 541 542 if ((error = suser(pc->pc_ucred, &p->p_acflag)) != 0) 543 return (error); 544 ngrp = SCARG(uap, gidsetsize); 545 if ((u_int)ngrp > NGROUPS) 546 return (EINVAL); 547 pc->pc_ucred = crcopy(pc->pc_ucred); 548 error = copyin(SCARG(uap, gidset), pc->pc_ucred->cr_groups, 549 ngrp * sizeof(gid_t)); 550 if (error) 551 return (error); 552 pc->pc_ucred->cr_ngroups = ngrp; 553 p_sugid(p); 554 return (0); 555 } 556 557 /* 558 * Check if gid is a member of the group set. 559 */ 560 int 561 groupmember(gid, cred) 562 gid_t gid; 563 struct ucred *cred; 564 { 565 gid_t *gp; 566 gid_t *egp; 567 568 egp = &(cred->cr_groups[cred->cr_ngroups]); 569 for (gp = cred->cr_groups; gp < egp; gp++) 570 if (*gp == gid) 571 return (1); 572 return (0); 573 } 574 575 /* 576 * Test whether the specified credentials imply "super-user" 577 * privilege; if so, and we have accounting info, set the flag 578 * indicating use of super-powers. 579 * Returns 0 or error. 580 */ 581 int 582 suser(cred, acflag) 583 struct ucred *cred; 584 u_short *acflag; 585 { 586 if (cred->cr_uid == 0) { 587 if (acflag) 588 *acflag |= ASU; 589 return (0); 590 } 591 return (EPERM); 592 } 593 594 /* 595 * Allocate a zeroed cred structure. 596 */ 597 struct ucred * 598 crget() 599 { 600 struct ucred *cr; 601 602 MALLOC(cr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK); 603 memset((caddr_t)cr, 0, sizeof(*cr)); 604 cr->cr_ref = 1; 605 return (cr); 606 } 607 608 /* 609 * Free a cred structure. 610 * Throws away space when ref count gets to 0. 611 */ 612 void 613 crfree(cr) 614 struct ucred *cr; 615 { 616 int s; 617 618 s = splimp(); /* ??? */ 619 if (--cr->cr_ref == 0) 620 FREE((caddr_t)cr, M_CRED); 621 (void) splx(s); 622 } 623 624 /* 625 * Copy cred structure to a new one and free the old one. 626 */ 627 struct ucred * 628 crcopy(cr) 629 struct ucred *cr; 630 { 631 struct ucred *newcr; 632 633 if (cr->cr_ref == 1) 634 return (cr); 635 newcr = crget(); 636 *newcr = *cr; 637 crfree(cr); 638 newcr->cr_ref = 1; 639 return (newcr); 640 } 641 642 /* 643 * Dup cred struct to a new held one. 644 */ 645 struct ucred * 646 crdup(cr) 647 struct ucred *cr; 648 { 649 struct ucred *newcr; 650 651 newcr = crget(); 652 *newcr = *cr; 653 newcr->cr_ref = 1; 654 return (newcr); 655 } 656 657 /* 658 * Get login name, if available. 659 */ 660 /* ARGSUSED */ 661 int 662 sys___getlogin(p, v, retval) 663 struct proc *p; 664 void *v; 665 register_t *retval; 666 { 667 struct sys___getlogin_args /* { 668 syscallarg(char *) namebuf; 669 syscallarg(size_t) namelen; 670 } */ *uap = v; 671 672 if (SCARG(uap, namelen) > sizeof(p->p_pgrp->pg_session->s_login)) 673 SCARG(uap, namelen) = sizeof(p->p_pgrp->pg_session->s_login); 674 return (copyout((caddr_t) p->p_pgrp->pg_session->s_login, 675 (caddr_t) SCARG(uap, namebuf), SCARG(uap, namelen))); 676 } 677 678 /* 679 * Set login name. 680 */ 681 /* ARGSUSED */ 682 int 683 sys_setlogin(p, v, retval) 684 struct proc *p; 685 void *v; 686 register_t *retval; 687 { 688 struct sys_setlogin_args /* { 689 syscallarg(const char *) namebuf; 690 } */ *uap = v; 691 int error; 692 693 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 694 return (error); 695 error = copyinstr(SCARG(uap, namebuf), p->p_pgrp->pg_session->s_login, 696 sizeof(p->p_pgrp->pg_session->s_login) - 1, (size_t *)0); 697 if (error == ENAMETOOLONG) 698 error = EINVAL; 699 return (error); 700 } 701
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