Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_prot.c
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1 /* $OpenBSD: kern_prot.c,v 1.82 2023/01/09 02:12:13 guenther Exp $ */ 2 /* $NetBSD: kern_prot.c,v 1.33 1996/02/09 18:59:42 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)kern_prot.c 8.6 (Berkeley) 1/21/94 38 */ 39 40 /* 41 * System calls related to processes and protection 42 */ 43 44 #include <sys/param.h> 45 #include <sys/atomic.h> 46 #include <sys/systm.h> 47 #include <sys/ucred.h> 48 #include <sys/proc.h> 49 #include <sys/filedesc.h> 50 #include <sys/pool.h> 51 52 #include <sys/mount.h> 53 #include <sys/syscallargs.h> 54 #include <machine/tcb.h> 55 56 inline void 57 crset(struct ucred *newcr, const struct ucred *cr) 58 { 59 KASSERT(cr->cr_refcnt.r_refs > 0); 60 memcpy( 61 (char *)newcr + offsetof(struct ucred, cr_startcopy), 62 (const char *)cr + offsetof(struct ucred, cr_startcopy), 63 sizeof(*cr) - offsetof(struct ucred, cr_startcopy)); 64 } 65 66 int 67 sys_getpid(struct proc *p, void *v, register_t *retval) 68 { 69 70 *retval = p->p_p->ps_pid; 71 return (0); 72 } 73 74 int 75 sys_getthrid(struct proc *p, void *v, register_t *retval) 76 { 77 78 *retval = p->p_tid + THREAD_PID_OFFSET; 79 return (0); 80 } 81 82 int 83 sys_getppid(struct proc *p, void *v, register_t *retval) 84 { 85 86 *retval = p->p_p->ps_ppid; 87 return (0); 88 } 89 90 /* Get process group ID; note that POSIX getpgrp takes no parameter */ 91 int 92 sys_getpgrp(struct proc *p, void *v, register_t *retval) 93 { 94 95 *retval = p->p_p->ps_pgrp->pg_id; 96 return (0); 97 } 98 99 /* 100 * SysVR.4 compatible getpgid() 101 */ 102 int 103 sys_getpgid(struct proc *curp, void *v, register_t *retval) 104 { 105 struct sys_getpgid_args /* { 106 syscallarg(pid_t) pid; 107 } */ *uap = v; 108 struct process *targpr = curp->p_p; 109 110 if (SCARG(uap, pid) == 0 || SCARG(uap, pid) == targpr->ps_pid) 111 goto found; 112 if ((targpr = prfind(SCARG(uap, pid))) == NULL) 113 return (ESRCH); 114 if (targpr->ps_session != curp->p_p->ps_session) 115 return (EPERM); 116 found: 117 *retval = targpr->ps_pgid; 118 return (0); 119 } 120 121 int 122 sys_getsid(struct proc *curp, void *v, register_t *retval) 123 { 124 struct sys_getsid_args /* { 125 syscallarg(pid_t) pid; 126 } */ *uap = v; 127 struct process *targpr = curp->p_p; 128 129 if (SCARG(uap, pid) == 0 || SCARG(uap, pid) == targpr->ps_pid) 130 goto found; 131 if ((targpr = prfind(SCARG(uap, pid))) == NULL) 132 return (ESRCH); 133 if (targpr->ps_session != curp->p_p->ps_session) 134 return (EPERM); 135 found: 136 /* Skip exiting processes */ 137 if (targpr->ps_pgrp->pg_session->s_leader == NULL) 138 return (ESRCH); 139 *retval = targpr->ps_pgrp->pg_session->s_leader->ps_pid; 140 return (0); 141 } 142 143 int 144 sys_getuid(struct proc *p, void *v, register_t *retval) 145 { 146 147 *retval = p->p_ucred->cr_ruid; 148 return (0); 149 } 150 151 int 152 sys_geteuid(struct proc *p, void *v, register_t *retval) 153 { 154 155 *retval = p->p_ucred->cr_uid; 156 return (0); 157 } 158 159 int 160 sys_issetugid(struct proc *p, void *v, register_t *retval) 161 { 162 if (p->p_p->ps_flags & PS_SUGIDEXEC) 163 *retval = 1; 164 else 165 *retval = 0; 166 return (0); 167 } 168 169 int 170 sys_getgid(struct proc *p, void *v, register_t *retval) 171 { 172 173 *retval = p->p_ucred->cr_rgid; 174 return (0); 175 } 176 177 /* 178 * Get effective group ID. The "egid" is groups[0], and could be obtained 179 * via getgroups. This syscall exists because it is somewhat painful to do 180 * correctly in a library function. 181 */ 182 int 183 sys_getegid(struct proc *p, void *v, register_t *retval) 184 { 185 186 *retval = p->p_ucred->cr_gid; 187 return (0); 188 } 189 190 int 191 sys_getgroups(struct proc *p, void *v, register_t *retval) 192 { 193 struct sys_getgroups_args /* { 194 syscallarg(int) gidsetsize; 195 syscallarg(gid_t *) gidset; 196 } */ *uap = v; 197 struct ucred *uc = p->p_ucred; 198 int ngrp; 199 int error; 200 201 if ((ngrp = SCARG(uap, gidsetsize)) == 0) { 202 *retval = uc->cr_ngroups; 203 return (0); 204 } 205 if (ngrp < uc->cr_ngroups) 206 return (EINVAL); 207 ngrp = uc->cr_ngroups; 208 error = copyout(uc->cr_groups, SCARG(uap, gidset), 209 ngrp * sizeof(gid_t)); 210 if (error) 211 return (error); 212 *retval = ngrp; 213 return (0); 214 } 215 216 int 217 sys_setsid(struct proc *p, void *v, register_t *retval) 218 { 219 struct session *newsess; 220 struct pgrp *newpgrp; 221 struct process *pr = p->p_p; 222 pid_t pid = pr->ps_pid; 223 224 newsess = pool_get(&session_pool, PR_WAITOK); 225 newpgrp = pool_get(&pgrp_pool, PR_WAITOK); 226 227 if (pr->ps_pgid == pid || pgfind(pid) != NULL) { 228 pool_put(&pgrp_pool, newpgrp); 229 pool_put(&session_pool, newsess); 230 return (EPERM); 231 } else { 232 enternewpgrp(pr, newpgrp, newsess); 233 *retval = pid; 234 return (0); 235 } 236 } 237 238 /* 239 * set process group (setpgid/old setpgrp) 240 * 241 * caller does setpgid(targpid, targpgid) 242 * 243 * pid must be caller or child of caller (ESRCH) 244 * if a child 245 * pid must be in same session (EPERM) 246 * pid can't have done an exec (EACCES) 247 * if pgid != pid 248 * there must exist some pid in same session having pgid (EPERM) 249 * pid must not be session leader (EPERM) 250 */ 251 int 252 sys_setpgid(struct proc *curp, void *v, register_t *retval) 253 { 254 struct sys_setpgid_args /* { 255 syscallarg(pid_t) pid; 256 syscallarg(pid_t) pgid; 257 } */ *uap = v; 258 struct process *curpr = curp->p_p; 259 struct process *targpr; /* target process */ 260 struct pgrp *pgrp, *newpgrp; /* target pgrp */ 261 pid_t pid, pgid; 262 int error; 263 264 pid = SCARG(uap, pid); 265 pgid = SCARG(uap, pgid); 266 267 if (pgid < 0) 268 return (EINVAL); 269 270 newpgrp = pool_get(&pgrp_pool, PR_WAITOK); 271 272 if (pid != 0 && pid != curpr->ps_pid) { 273 if ((targpr = prfind(pid)) == NULL || 274 !inferior(targpr, curpr)) { 275 error = ESRCH; 276 goto out; 277 } 278 if (targpr->ps_session != curpr->ps_session) { 279 error = EPERM; 280 goto out; 281 } 282 if (targpr->ps_flags & PS_EXEC) { 283 error = EACCES; 284 goto out; 285 } 286 } else 287 targpr = curpr; 288 if (SESS_LEADER(targpr)) { 289 error = EPERM; 290 goto out; 291 } 292 if (pgid == 0) 293 pgid = targpr->ps_pid; 294 295 error = 0; 296 if ((pgrp = pgfind(pgid)) == NULL) { 297 /* can only create a new process group with pgid == pid */ 298 if (pgid != targpr->ps_pid) 299 error = EPERM; 300 else { 301 enternewpgrp(targpr, newpgrp, NULL); 302 newpgrp = NULL; 303 } 304 } else if (pgrp != targpr->ps_pgrp) { /* anything to do? */ 305 if (pgid != targpr->ps_pid && 306 pgrp->pg_session != curpr->ps_session) 307 error = EPERM; 308 else 309 enterthispgrp(targpr, pgrp); 310 } 311 out: 312 if (newpgrp != NULL) 313 pool_put(&pgrp_pool, newpgrp); 314 return (error); 315 } 316 317 int 318 sys_getresuid(struct proc *p, void *v, register_t *retval) 319 { 320 struct sys_getresuid_args /* { 321 syscallarg(uid_t *) ruid; 322 syscallarg(uid_t *) euid; 323 syscallarg(uid_t *) suid; 324 } */ *uap = v; 325 struct ucred *uc = p->p_ucred; 326 uid_t *ruid, *euid, *suid; 327 int error1 = 0, error2 = 0, error3 = 0; 328 329 ruid = SCARG(uap, ruid); 330 euid = SCARG(uap, euid); 331 suid = SCARG(uap, suid); 332 333 if (ruid != NULL) 334 error1 = copyout(&uc->cr_ruid, ruid, sizeof(*ruid)); 335 if (euid != NULL) 336 error2 = copyout(&uc->cr_uid, euid, sizeof(*euid)); 337 if (suid != NULL) 338 error3 = copyout(&uc->cr_svuid, suid, sizeof(*suid)); 339 340 return (error1 ? error1 : error2 ? error2 : error3); 341 } 342 343 int 344 sys_setresuid(struct proc *p, void *v, register_t *retval) 345 { 346 struct sys_setresuid_args /* { 347 syscallarg(uid_t) ruid; 348 syscallarg(uid_t) euid; 349 syscallarg(uid_t) suid; 350 } */ *uap = v; 351 struct process *pr = p->p_p; 352 struct ucred *pruc, *newcred, *uc = p->p_ucred; 353 uid_t ruid, euid, suid; 354 int error; 355 356 ruid = SCARG(uap, ruid); 357 euid = SCARG(uap, euid); 358 suid = SCARG(uap, suid); 359 360 /* 361 * make permission checks against the thread's ucred, 362 * but the actual changes will be to the process's ucred 363 */ 364 pruc = pr->ps_ucred; 365 if ((ruid == (uid_t)-1 || ruid == pruc->cr_ruid) && 366 (euid == (uid_t)-1 || euid == pruc->cr_uid) && 367 (suid == (uid_t)-1 || suid == pruc->cr_svuid)) 368 return (0); /* no change */ 369 370 /* 371 * Any of the real, effective, and saved uids may be changed 372 * to the current value of one of the three (root is not limited). 373 */ 374 if (ruid != (uid_t)-1 && 375 ruid != uc->cr_ruid && 376 ruid != uc->cr_uid && 377 ruid != uc->cr_svuid && 378 (error = suser(p))) 379 return (error); 380 381 if (euid != (uid_t)-1 && 382 euid != uc->cr_ruid && 383 euid != uc->cr_uid && 384 euid != uc->cr_svuid && 385 (error = suser(p))) 386 return (error); 387 388 if (suid != (uid_t)-1 && 389 suid != uc->cr_ruid && 390 suid != uc->cr_uid && 391 suid != uc->cr_svuid && 392 (error = suser(p))) 393 return (error); 394 395 /* 396 * Copy credentials so other references do not see our changes. 397 * ps_ucred may change during the crget(). 398 */ 399 newcred = crget(); 400 pruc = pr->ps_ucred; 401 crset(newcred, pruc); 402 403 /* 404 * Note that unlike the other set*uid() calls, each 405 * uid type is set independently of the others. 406 */ 407 if (ruid != (uid_t)-1) 408 newcred->cr_ruid = ruid; 409 if (euid != (uid_t)-1) 410 newcred->cr_uid = euid; 411 if (suid != (uid_t)-1) 412 newcred->cr_svuid = suid; 413 pr->ps_ucred = newcred; 414 atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); 415 416 /* now that we can sleep, transfer proc count to new user */ 417 if (ruid != (uid_t)-1 && ruid != pruc->cr_ruid) { 418 chgproccnt(pruc->cr_ruid, -1); 419 chgproccnt(ruid, 1); 420 } 421 crfree(pruc); 422 423 return (0); 424 } 425 426 int 427 sys_getresgid(struct proc *p, void *v, register_t *retval) 428 { 429 struct sys_getresgid_args /* { 430 syscallarg(gid_t *) rgid; 431 syscallarg(gid_t *) egid; 432 syscallarg(gid_t *) sgid; 433 } */ *uap = v; 434 struct ucred *uc = p->p_ucred; 435 gid_t *rgid, *egid, *sgid; 436 int error1 = 0, error2 = 0, error3 = 0; 437 438 rgid = SCARG(uap, rgid); 439 egid = SCARG(uap, egid); 440 sgid = SCARG(uap, sgid); 441 442 if (rgid != NULL) 443 error1 = copyout(&uc->cr_rgid, rgid, sizeof(*rgid)); 444 if (egid != NULL) 445 error2 = copyout(&uc->cr_gid, egid, sizeof(*egid)); 446 if (sgid != NULL) 447 error3 = copyout(&uc->cr_svgid, sgid, sizeof(*sgid)); 448 449 return (error1 ? error1 : error2 ? error2 : error3); 450 } 451 452 int 453 sys_setresgid(struct proc *p, void *v, register_t *retval) 454 { 455 struct sys_setresgid_args /* { 456 syscallarg(gid_t) rgid; 457 syscallarg(gid_t) egid; 458 syscallarg(gid_t) sgid; 459 } */ *uap = v; 460 struct process *pr = p->p_p; 461 struct ucred *pruc, *newcred, *uc = p->p_ucred; 462 gid_t rgid, egid, sgid; 463 int error; 464 465 rgid = SCARG(uap, rgid); 466 egid = SCARG(uap, egid); 467 sgid = SCARG(uap, sgid); 468 469 /* 470 * make permission checks against the thread's ucred, 471 * but the actual changes will be to the process's ucred 472 */ 473 pruc = pr->ps_ucred; 474 if ((rgid == (gid_t)-1 || rgid == pruc->cr_rgid) && 475 (egid == (gid_t)-1 || egid == pruc->cr_gid) && 476 (sgid == (gid_t)-1 || sgid == pruc->cr_svgid)) 477 return (0); /* no change */ 478 479 /* 480 * Any of the real, effective, and saved gids may be changed 481 * to the current value of one of the three (root is not limited). 482 */ 483 if (rgid != (gid_t)-1 && 484 rgid != uc->cr_rgid && 485 rgid != uc->cr_gid && 486 rgid != uc->cr_svgid && 487 (error = suser(p))) 488 return (error); 489 490 if (egid != (gid_t)-1 && 491 egid != uc->cr_rgid && 492 egid != uc->cr_gid && 493 egid != uc->cr_svgid && 494 (error = suser(p))) 495 return (error); 496 497 if (sgid != (gid_t)-1 && 498 sgid != uc->cr_rgid && 499 sgid != uc->cr_gid && 500 sgid != uc->cr_svgid && 501 (error = suser(p))) 502 return (error); 503 504 /* 505 * Copy credentials so other references do not see our changes. 506 * ps_ucred may change during the crget(). 507 */ 508 newcred = crget(); 509 pruc = pr->ps_ucred; 510 crset(newcred, pruc); 511 512 /* 513 * Note that unlike the other set*gid() calls, each 514 * gid type is set independently of the others. 515 */ 516 if (rgid != (gid_t)-1) 517 newcred->cr_rgid = rgid; 518 if (egid != (gid_t)-1) 519 newcred->cr_gid = egid; 520 if (sgid != (gid_t)-1) 521 newcred->cr_svgid = sgid; 522 pr->ps_ucred = newcred; 523 atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); 524 crfree(pruc); 525 return (0); 526 } 527 528 int 529 sys_setregid(struct proc *p, void *v, register_t *retval) 530 { 531 struct sys_setregid_args /* { 532 syscallarg(gid_t) rgid; 533 syscallarg(gid_t) egid; 534 } */ *uap = v; 535 struct process *pr = p->p_p; 536 struct ucred *pruc, *newcred, *uc = p->p_ucred; 537 gid_t rgid, egid; 538 int error; 539 540 rgid = SCARG(uap, rgid); 541 egid = SCARG(uap, egid); 542 543 /* 544 * make permission checks against the thread's ucred, 545 * but the actual changes will be to the process's ucred 546 * 547 * The saved gid check here is complicated: we reset the 548 * saved gid to the real gid if the real gid is specified 549 * *and* either it's changing _or_ the saved gid won't equal 550 * the effective gid. So, the svgid *won't* change when 551 * the rgid isn't specified or when the rgid isn't changing 552 * and the svgid equals the requested egid. 553 */ 554 pruc = pr->ps_ucred; 555 if ((rgid == (gid_t)-1 || rgid == pruc->cr_rgid) && 556 (egid == (gid_t)-1 || egid == pruc->cr_gid) && 557 (rgid == (gid_t)-1 || (rgid == pruc->cr_rgid && 558 pruc->cr_svgid == (egid != (gid_t)-1 ? egid : pruc->cr_gid)))) 559 return (0); /* no change */ 560 561 /* 562 * Any of the real, effective, and saved gids may be changed 563 * to the current value of one of the three (root is not limited). 564 */ 565 if (rgid != (gid_t)-1 && 566 rgid != uc->cr_rgid && 567 rgid != uc->cr_gid && 568 rgid != uc->cr_svgid && 569 (error = suser(p))) 570 return (error); 571 572 if (egid != (gid_t)-1 && 573 egid != uc->cr_rgid && 574 egid != uc->cr_gid && 575 egid != uc->cr_svgid && 576 (error = suser(p))) 577 return (error); 578 579 /* 580 * Copy credentials so other references do not see our changes. 581 * ps_ucred may change during the crget(). 582 */ 583 newcred = crget(); 584 pruc = pr->ps_ucred; 585 crset(newcred, pruc); 586 587 if (rgid != (gid_t)-1) 588 newcred->cr_rgid = rgid; 589 if (egid != (gid_t)-1) 590 newcred->cr_gid = egid; 591 592 /* 593 * The saved gid presents a bit of a dilemma, as it did not 594 * exist when setregid(2) was conceived. We only set the saved 595 * gid when the real gid is specified and either its value would 596 * change, or where the saved and effective gids are different. 597 */ 598 if (rgid != (gid_t)-1 && (rgid != pruc->cr_rgid || 599 pruc->cr_svgid != (egid != (gid_t)-1 ? egid : pruc->cr_gid))) 600 newcred->cr_svgid = rgid; 601 pr->ps_ucred = newcred; 602 atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); 603 crfree(pruc); 604 return (0); 605 } 606 607 int 608 sys_setreuid(struct proc *p, void *v, register_t *retval) 609 { 610 struct sys_setreuid_args /* { 611 syscallarg(uid_t) ruid; 612 syscallarg(uid_t) euid; 613 } */ *uap = v; 614 struct process *pr = p->p_p; 615 struct ucred *pruc, *newcred, *uc = p->p_ucred; 616 uid_t ruid, euid; 617 int error; 618 619 ruid = SCARG(uap, ruid); 620 euid = SCARG(uap, euid); 621 622 /* 623 * make permission checks against the thread's ucred, 624 * but the actual changes will be to the process's ucred 625 * 626 * The saved uid check here is complicated: we reset the 627 * saved uid to the real uid if the real uid is specified 628 * *and* either it's changing _or_ the saved uid won't equal 629 * the effective uid. So, the svuid *won't* change when 630 * the ruid isn't specified or when the ruid isn't changing 631 * and the svuid equals the requested euid. 632 */ 633 pruc = pr->ps_ucred; 634 if ((ruid == (uid_t)-1 || ruid == pruc->cr_ruid) && 635 (euid == (uid_t)-1 || euid == pruc->cr_uid) && 636 (ruid == (uid_t)-1 || (ruid == pruc->cr_ruid && 637 pruc->cr_svuid == (euid != (uid_t)-1 ? euid : pruc->cr_uid)))) 638 return (0); /* no change */ 639 640 /* 641 * Any of the real, effective, and saved uids may be changed 642 * to the current value of one of the three (root is not limited). 643 */ 644 if (ruid != (uid_t)-1 && 645 ruid != uc->cr_ruid && 646 ruid != uc->cr_uid && 647 ruid != uc->cr_svuid && 648 (error = suser(p))) 649 return (error); 650 651 if (euid != (uid_t)-1 && 652 euid != uc->cr_ruid && 653 euid != uc->cr_uid && 654 euid != uc->cr_svuid && 655 (error = suser(p))) 656 return (error); 657 658 /* 659 * Copy credentials so other references do not see our changes. 660 * ps_ucred may change during the crget(). 661 */ 662 newcred = crget(); 663 pruc = pr->ps_ucred; 664 crset(newcred, pruc); 665 666 if (ruid != (uid_t)-1) 667 newcred->cr_ruid = ruid; 668 if (euid != (uid_t)-1) 669 newcred->cr_uid = euid; 670 671 /* 672 * The saved uid presents a bit of a dilemma, as it did not 673 * exist when setreuid(2) was conceived. We only set the saved 674 * uid when the real uid is specified and either its value would 675 * change, or where the saved and effective uids are different. 676 */ 677 if (ruid != (uid_t)-1 && (ruid != pruc->cr_ruid || 678 pruc->cr_svuid != (euid != (uid_t)-1 ? euid : pruc->cr_uid))) 679 newcred->cr_svuid = ruid; 680 pr->ps_ucred = newcred; 681 atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); 682 683 /* now that we can sleep, transfer proc count to new user */ 684 if (ruid != (uid_t)-1 && ruid != pruc->cr_ruid) { 685 chgproccnt(pruc->cr_ruid, -1); 686 chgproccnt(ruid, 1); 687 } 688 crfree(pruc); 689 690 return (0); 691 } 692 693 int 694 sys_setuid(struct proc *p, void *v, register_t *retval) 695 { 696 struct sys_setuid_args /* { 697 syscallarg(uid_t) uid; 698 } */ *uap = v; 699 struct process *pr = p->p_p; 700 struct ucred *pruc, *newcred, *uc = p->p_ucred; 701 uid_t uid; 702 int did_real, error; 703 704 uid = SCARG(uap, uid); 705 706 pruc = pr->ps_ucred; 707 if (pruc->cr_uid == uid && 708 pruc->cr_ruid == uid && 709 pruc->cr_svuid == uid) 710 return (0); 711 712 if (uid != uc->cr_ruid && 713 uid != uc->cr_svuid && 714 uid != uc->cr_uid && 715 (error = suser(p))) 716 return (error); 717 718 /* 719 * Copy credentials so other references do not see our changes. 720 * ps_ucred may change during the crget(). 721 */ 722 newcred = crget(); 723 pruc = pr->ps_ucred; 724 crset(newcred, pruc); 725 726 /* 727 * Everything's okay, do it. 728 */ 729 if (uid == pruc->cr_uid || suser(p) == 0) { 730 did_real = 1; 731 newcred->cr_ruid = uid; 732 newcred->cr_svuid = uid; 733 } else 734 did_real = 0; 735 newcred->cr_uid = uid; 736 pr->ps_ucred = newcred; 737 atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); 738 739 /* 740 * Transfer proc count to new user. 741 */ 742 if (did_real && uid != pruc->cr_ruid) { 743 chgproccnt(pruc->cr_ruid, -1); 744 chgproccnt(uid, 1); 745 } 746 crfree(pruc); 747 748 return (0); 749 } 750 751 int 752 sys_seteuid(struct proc *p, void *v, register_t *retval) 753 { 754 struct sys_seteuid_args /* { 755 syscallarg(uid_t) euid; 756 } */ *uap = v; 757 struct process *pr = p->p_p; 758 struct ucred *pruc, *newcred, *uc = p->p_ucred; 759 uid_t euid; 760 int error; 761 762 euid = SCARG(uap, euid); 763 764 if (pr->ps_ucred->cr_uid == euid) 765 return (0); 766 767 if (euid != uc->cr_ruid && euid != uc->cr_svuid && 768 (error = suser(p))) 769 return (error); 770 771 /* 772 * Copy credentials so other references do not see our changes. 773 * ps_ucred may change during the crget(). 774 */ 775 newcred = crget(); 776 pruc = pr->ps_ucred; 777 crset(newcred, pruc); 778 newcred->cr_uid = euid; 779 pr->ps_ucred = newcred; 780 atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); 781 crfree(pruc); 782 return (0); 783 } 784 785 int 786 sys_setgid(struct proc *p, void *v, register_t *retval) 787 { 788 struct sys_setgid_args /* { 789 syscallarg(gid_t) gid; 790 } */ *uap = v; 791 struct process *pr = p->p_p; 792 struct ucred *pruc, *newcred, *uc = p->p_ucred; 793 gid_t gid; 794 int error; 795 796 gid = SCARG(uap, gid); 797 798 pruc = pr->ps_ucred; 799 if (pruc->cr_gid == gid && 800 pruc->cr_rgid == gid && 801 pruc->cr_svgid == gid) 802 return (0); 803 804 if (gid != uc->cr_rgid && 805 gid != uc->cr_svgid && 806 gid != uc->cr_gid && 807 (error = suser(p))) 808 return (error); 809 810 /* 811 * Copy credentials so other references do not see our changes. 812 * ps_ucred may change during the crget(). 813 */ 814 newcred = crget(); 815 pruc = pr->ps_ucred; 816 crset(newcred, pruc); 817 818 if (gid == pruc->cr_gid || suser(p) == 0) { 819 newcred->cr_rgid = gid; 820 newcred->cr_svgid = gid; 821 } 822 newcred->cr_gid = gid; 823 pr->ps_ucred = newcred; 824 atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); 825 crfree(pruc); 826 return (0); 827 } 828 829 int 830 sys_setegid(struct proc *p, void *v, register_t *retval) 831 { 832 struct sys_setegid_args /* { 833 syscallarg(gid_t) egid; 834 } */ *uap = v; 835 struct process *pr = p->p_p; 836 struct ucred *pruc, *newcred, *uc = p->p_ucred; 837 gid_t egid; 838 int error; 839 840 egid = SCARG(uap, egid); 841 842 if (pr->ps_ucred->cr_gid == egid) 843 return (0); 844 845 if (egid != uc->cr_rgid && egid != uc->cr_svgid && 846 (error = suser(p))) 847 return (error); 848 849 /* 850 * Copy credentials so other references do not see our changes. 851 * ps_ucred may change during the crget(). 852 */ 853 newcred = crget(); 854 pruc = pr->ps_ucred; 855 crset(newcred, pruc); 856 newcred->cr_gid = egid; 857 pr->ps_ucred = newcred; 858 atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); 859 crfree(pruc); 860 return (0); 861 } 862 863 int 864 sys_setgroups(struct proc *p, void *v, register_t *retval) 865 { 866 struct sys_setgroups_args /* { 867 syscallarg(int) gidsetsize; 868 syscallarg(const gid_t *) gidset; 869 } */ *uap = v; 870 struct process *pr = p->p_p; 871 struct ucred *pruc, *newcred; 872 gid_t groups[NGROUPS_MAX]; 873 int ngrp; 874 int error; 875 876 if ((error = suser(p)) != 0) 877 return (error); 878 ngrp = SCARG(uap, gidsetsize); 879 if (ngrp > NGROUPS_MAX || ngrp < 0) 880 return (EINVAL); 881 error = copyin(SCARG(uap, gidset), groups, ngrp * sizeof(gid_t)); 882 if (error == 0) { 883 newcred = crget(); 884 pruc = pr->ps_ucred; 885 crset(newcred, pruc); 886 memcpy(newcred->cr_groups, groups, ngrp * sizeof(gid_t)); 887 newcred->cr_ngroups = ngrp; 888 pr->ps_ucred = newcred; 889 atomic_setbits_int(&p->p_p->ps_flags, PS_SUGID); 890 crfree(pruc); 891 } 892 return (error); 893 } 894 895 /* 896 * Check if gid is a member of the group set. 897 */ 898 int 899 groupmember(gid_t gid, struct ucred *cred) 900 { 901 gid_t *gp; 902 gid_t *egp; 903 904 if (cred->cr_gid == gid) 905 return (1); 906 egp = &(cred->cr_groups[cred->cr_ngroups]); 907 for (gp = cred->cr_groups; gp < egp; gp++) 908 if (*gp == gid) 909 return (1); 910 return (0); 911 } 912 913 /* 914 * Test whether this process has special user powers. 915 * Returns 0 or error. 916 */ 917 int 918 suser(struct proc *p) 919 { 920 struct ucred *cred = p->p_ucred; 921 922 if (cred->cr_uid == 0) 923 return (0); 924 return (EPERM); 925 } 926 927 /* 928 * replacement for old suser, for callers who don't have a process 929 */ 930 int 931 suser_ucred(struct ucred *cred) 932 { 933 if (cred->cr_uid == 0) 934 return (0); 935 return (EPERM); 936 } 937 938 /* 939 * Allocate a zeroed cred structure. 940 */ 941 struct ucred * 942 crget(void) 943 { 944 struct ucred *cr; 945 946 cr = pool_get(&ucred_pool, PR_WAITOK|PR_ZERO); 947 refcnt_init(&cr->cr_refcnt); 948 return (cr); 949 } 950 951 /* 952 * Increment the reference count of a cred structure. 953 * Returns the passed structure. 954 */ 955 struct ucred * 956 crhold(struct ucred *cr) 957 { 958 refcnt_take(&cr->cr_refcnt); 959 return (cr); 960 } 961 962 /* 963 * Free a cred structure. 964 * Throws away space when ref count gets to 0. 965 */ 966 void 967 crfree(struct ucred *cr) 968 { 969 if (refcnt_rele(&cr->cr_refcnt)) 970 pool_put(&ucred_pool, cr); 971 } 972 973 /* 974 * Copy cred structure to a new one and free the old one. 975 */ 976 struct ucred * 977 crcopy(struct ucred *cr) 978 { 979 struct ucred *newcr; 980 981 if (!refcnt_shared(&cr->cr_refcnt)) 982 return (cr); 983 newcr = crget(); 984 *newcr = *cr; 985 crfree(cr); 986 refcnt_init(&newcr->cr_refcnt); 987 return (newcr); 988 } 989 990 /* 991 * Dup cred struct to a new held one. 992 */ 993 struct ucred * 994 crdup(struct ucred *cr) 995 { 996 struct ucred *newcr; 997 998 newcr = crget(); 999 *newcr = *cr; 1000 refcnt_init(&newcr->cr_refcnt); 1001 return (newcr); 1002 } 1003 1004 /* 1005 * Convert the userspace xucred to a kernel ucred 1006 */ 1007 int 1008 crfromxucred(struct ucred *cr, const struct xucred *xcr) 1009 { 1010 if (xcr->cr_ngroups < 0 || xcr->cr_ngroups > NGROUPS_MAX) 1011 return (EINVAL); 1012 refcnt_init(&cr->cr_refcnt); 1013 cr->cr_uid = xcr->cr_uid; 1014 cr->cr_gid = xcr->cr_gid; 1015 cr->cr_ngroups = xcr->cr_ngroups; 1016 memcpy(cr->cr_groups, xcr->cr_groups, 1017 sizeof(cr->cr_groups[0]) * xcr->cr_ngroups); 1018 return (0); 1019 } 1020 1021 /* 1022 * Get login name, if available. 1023 */ 1024 int 1025 sys_getlogin_r(struct proc *p, void *v, register_t *retval) 1026 { 1027 struct sys_getlogin_r_args /* { 1028 syscallarg(char *) namebuf; 1029 syscallarg(size_t) namelen; 1030 } */ *uap = v; 1031 size_t namelen = SCARG(uap, namelen); 1032 struct session *s = p->p_p->ps_pgrp->pg_session; 1033 int error; 1034 1035 if (namelen > sizeof(s->s_login)) 1036 namelen = sizeof(s->s_login); 1037 error = copyoutstr(s->s_login, SCARG(uap, namebuf), namelen, NULL); 1038 if (error == ENAMETOOLONG) 1039 error = ERANGE; 1040 *retval = error; 1041 return (0); 1042 } 1043 1044 /* 1045 * Set login name. 1046 */ 1047 int 1048 sys_setlogin(struct proc *p, void *v, register_t *retval) 1049 { 1050 struct sys_setlogin_args /* { 1051 syscallarg(const char *) namebuf; 1052 } */ *uap = v; 1053 struct session *s = p->p_p->ps_pgrp->pg_session; 1054 char buf[sizeof(s->s_login)]; 1055 int error; 1056 1057 if ((error = suser(p)) != 0) 1058 return (error); 1059 error = copyinstr(SCARG(uap, namebuf), buf, sizeof(buf), NULL); 1060 if (error == 0) 1061 strlcpy(s->s_login, buf, sizeof(s->s_login)); 1062 else if (error == ENAMETOOLONG) 1063 error = EINVAL; 1064 return (error); 1065 } 1066 1067 /* 1068 * Check if a process is allowed to raise its privileges. 1069 */ 1070 int 1071 proc_cansugid(struct proc *p) 1072 { 1073 /* ptrace(2)d processes shouldn't. */ 1074 if ((p->p_p->ps_flags & PS_TRACED) != 0) 1075 return (0); 1076 1077 /* processes with shared filedescriptors shouldn't. */ 1078 if (p->p_fd->fd_refcnt > 1) 1079 return (0); 1080 1081 /* Allow. */ 1082 return (1); 1083 } 1084 1085 /* 1086 * Set address of the proc's thread-control-block 1087 */ 1088 int 1089 sys___set_tcb(struct proc *p, void *v, register_t *retval) 1090 { 1091 struct sys___set_tcb_args /* { 1092 syscallarg(void *) tcb; 1093 } */ *uap = v; 1094 void *tcb = SCARG(uap, tcb); 1095 1096 #ifdef TCB_INVALID 1097 if (TCB_INVALID(tcb)) 1098 return EINVAL; 1099 #endif /* TCB_INVALID */ 1100 TCB_SET(p, tcb); 1101 return (0); 1102 } 1103 1104 /* 1105 * Get address of the proc's thread-control-block 1106 */ 1107 int 1108 sys___get_tcb(struct proc *p, void *v, register_t *retval) 1109 { 1110 *retval = (register_t)TCB_GET(p); 1111 return (0); 1112 } 1113 1114 int 1115 sys_getthrname(struct proc *curp, void *v, register_t *retval) 1116 { 1117 struct sys_getthrname_args /* { 1118 syscallarg(pid_t) tid; 1119 syscallarg(char *) name; 1120 syscallarg(size_t) len; 1121 } */ *uap = v; 1122 struct proc *p; 1123 size_t len; 1124 int tid = SCARG(uap, tid); 1125 int error; 1126 1127 p = tid ? tfind_user(tid, curp->p_p) : curp; 1128 if (p == NULL) 1129 return ESRCH; 1130 1131 len = SCARG(uap, len); 1132 if (len > sizeof(p->p_name)) 1133 len = sizeof(p->p_name); 1134 error = copyoutstr(p->p_name, SCARG(uap, name), len, NULL); 1135 if (error == ENAMETOOLONG) 1136 error = ERANGE; 1137 *retval = error; 1138 return 0; 1139 } 1140 1141 int 1142 sys_setthrname(struct proc *curp, void *v, register_t *retval) 1143 { 1144 struct sys_setthrname_args /* { 1145 syscallarg(pid_t) tid; 1146 syscallarg(const char *) name; 1147 } */ *uap = v; 1148 struct proc *p; 1149 char buf[sizeof p->p_name]; 1150 int tid = SCARG(uap, tid); 1151 int error; 1152 1153 p = tid ? tfind_user(tid, curp->p_p) : curp; 1154 if (p == NULL) 1155 return ESRCH; 1156 1157 error = copyinstr(SCARG(uap, name), buf, sizeof buf, NULL); 1158 if (error == 0) 1159 strlcpy(p->p_name, buf, sizeof(p->p_name)); 1160 else if (error == ENAMETOOLONG) 1161 error = EINVAL; 1162 *retval = error; 1163 return 0; 1164 } 1165 1166 /* 1167 * Refresh the thread's reference to the process's credentials 1168 */ 1169 void 1170 dorefreshcreds(struct process *pr, struct proc *p) 1171 { 1172 struct ucred *uc = p->p_ucred; 1173 1174 KERNEL_LOCK(); /* XXX should be PROCESS_RLOCK(pr) */ 1175 if (uc != pr->ps_ucred) { 1176 p->p_ucred = pr->ps_ucred; 1177 crhold(p->p_ucred); 1178 crfree(uc); 1179 } 1180 KERNEL_UNLOCK(); 1181 }
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