1 /* $NetBSD: kern_prot.c,v 1.108 2008/10/11 13:40:57 pooka 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. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)kern_prot.c 8.9 (Berkeley) 2/14/95 37 */ 38 39 /* 40 * System calls related to processes and protection 41 */ 42 43 #include <sys/cdefs.h> 44 __KERNEL_RCSID(0, "$NetBSD: kern_prot.c,v 1.108 2008/10/11 13:40:57 pooka Exp $"); 45 46 #include "opt_compat_43.h" 47 48 #include <sys/param.h> 49 #include <sys/acct.h> 50 #include <sys/systm.h> 51 #include <sys/ucred.h> 52 #include <sys/proc.h> 53 #include <sys/timeb.h> 54 #include <sys/times.h> 55 #include <sys/pool.h> 56 #include <sys/prot.h> 57 #include <sys/syslog.h> 58 #include <sys/uidinfo.h> 59 #include <sys/kauth.h> 60 61 #include <sys/mount.h> 62 #include <sys/syscallargs.h> 63 64 int sys_getpid(struct lwp *, const void *, register_t *); 65 int sys_getpid_with_ppid(struct lwp *, const void *, register_t *); 66 int sys_getuid(struct lwp *, const void *, register_t *); 67 int sys_getuid_with_euid(struct lwp *, const void *, register_t *); 68 int sys_getgid(struct lwp *, const void *, register_t *); 69 int sys_getgid_with_egid(struct lwp *, const void *, register_t *); 70 71 /* ARGSUSED */ 72 int 73 sys_getpid(struct lwp *l, const void *v, register_t *retval) 74 { 75 struct proc *p = l->l_proc; 76 77 *retval = p->p_pid; 78 return (0); 79 } 80 81 /* ARGSUSED */ 82 int 83 sys_getpid_with_ppid(struct lwp *l, const void *v, register_t *retval) 84 { 85 struct proc *p = l->l_proc; 86 87 retval[0] = p->p_pid; 88 retval[1] = p->p_ppid; 89 return (0); 90 } 91 92 /* ARGSUSED */ 93 int 94 sys_getppid(struct lwp *l, const void *v, register_t *retval) 95 { 96 struct proc *p = l->l_proc; 97 98 *retval = p->p_ppid; 99 return (0); 100 } 101 102 /* Get process group ID; note that POSIX getpgrp takes no parameter */ 103 int 104 sys_getpgrp(struct lwp *l, const void *v, register_t *retval) 105 { 106 struct proc *p = l->l_proc; 107 108 mutex_enter(proc_lock); 109 *retval = p->p_pgrp->pg_id; 110 mutex_exit(proc_lock); 111 return (0); 112 } 113 114 /* 115 * Return the process group ID of the session leader (session ID) 116 * for the specified process. 117 */ 118 int 119 sys_getsid(struct lwp *l, const struct sys_getsid_args *uap, register_t *retval) 120 { 121 /* { 122 syscalldarg(pid_t) pid; 123 } */ 124 pid_t pid = SCARG(uap, pid); 125 struct proc *p; 126 int error = 0; 127 128 mutex_enter(proc_lock); 129 if (pid == 0) 130 *retval = l->l_proc->p_session->s_sid; 131 else if ((p = p_find(pid, PFIND_LOCKED)) != NULL) 132 *retval = p->p_session->s_sid; 133 else 134 error = ESRCH; 135 mutex_exit(proc_lock); 136 137 return error; 138 } 139 140 int 141 sys_getpgid(struct lwp *l, const struct sys_getpgid_args *uap, register_t *retval) 142 { 143 /* { 144 syscallarg(pid_t) pid; 145 } */ 146 pid_t pid = SCARG(uap, pid); 147 struct proc *p; 148 int error = 0; 149 150 mutex_enter(proc_lock); 151 if (pid == 0) 152 *retval = l->l_proc->p_pgid; 153 else if ((p = p_find(pid, PFIND_LOCKED)) != NULL) 154 *retval = p->p_pgid; 155 else 156 error = ESRCH; 157 mutex_exit(proc_lock); 158 159 return error; 160 } 161 162 /* ARGSUSED */ 163 int 164 sys_getuid(struct lwp *l, const void *v, register_t *retval) 165 { 166 167 *retval = kauth_cred_getuid(l->l_cred); 168 return (0); 169 } 170 171 /* ARGSUSED */ 172 int 173 sys_getuid_with_euid(struct lwp *l, const void *v, register_t *retval) 174 { 175 176 retval[0] = kauth_cred_getuid(l->l_cred); 177 retval[1] = kauth_cred_geteuid(l->l_cred); 178 return (0); 179 } 180 181 /* ARGSUSED */ 182 int 183 sys_geteuid(struct lwp *l, const void *v, register_t *retval) 184 { 185 186 *retval = kauth_cred_geteuid(l->l_cred); 187 return (0); 188 } 189 190 /* ARGSUSED */ 191 int 192 sys_getgid(struct lwp *l, const void *v, register_t *retval) 193 { 194 195 *retval = kauth_cred_getgid(l->l_cred); 196 return (0); 197 } 198 199 /* ARGSUSED */ 200 int 201 sys_getgid_with_egid(struct lwp *l, const void *v, register_t *retval) 202 { 203 204 retval[0] = kauth_cred_getgid(l->l_cred); 205 retval[1] = kauth_cred_getegid(l->l_cred); 206 return (0); 207 } 208 209 /* 210 * Get effective group ID. The "egid" is groups[0], and could be obtained 211 * via getgroups. This syscall exists because it is somewhat painful to do 212 * correctly in a library function. 213 */ 214 /* ARGSUSED */ 215 int 216 sys_getegid(struct lwp *l, const void *v, register_t *retval) 217 { 218 219 *retval = kauth_cred_getegid(l->l_cred); 220 return (0); 221 } 222 223 int 224 sys_getgroups(struct lwp *l, const struct sys_getgroups_args *uap, register_t *retval) 225 { 226 /* { 227 syscallarg(int) gidsetsize; 228 syscallarg(gid_t *) gidset; 229 } */ 230 231 *retval = kauth_cred_ngroups(l->l_cred); 232 if (SCARG(uap, gidsetsize) == 0) 233 return 0; 234 if (SCARG(uap, gidsetsize) < *retval) 235 return EINVAL; 236 237 return kauth_cred_getgroups(l->l_cred, SCARG(uap, gidset), *retval, 238 UIO_USERSPACE); 239 } 240 241 /* ARGSUSED */ 242 int 243 sys_setsid(struct lwp *l, const void *v, register_t *retval) 244 { 245 struct proc *p = l->l_proc; 246 int error; 247 248 error = enterpgrp(p, p->p_pid, p->p_pid, 1); 249 *retval = p->p_pid; 250 return (error); 251 } 252 253 254 /* 255 * set process group (setpgid/old setpgrp) 256 * 257 * caller does setpgid(targpid, targpgid) 258 * 259 * pgid must be in valid range (EINVAL) 260 * pid must be caller or child of caller (ESRCH) 261 * if a child 262 * pid must be in same session (EPERM) 263 * pid can't have done an exec (EACCES) 264 * if pgid != pid 265 * there must exist some pid in same session having pgid (EPERM) 266 * pid must not be session leader (EPERM) 267 * 268 * Permission checks now in enterpgrp() 269 */ 270 /* ARGSUSED */ 271 int 272 sys_setpgid(struct lwp *l, const struct sys_setpgid_args *uap, register_t *retval) 273 { 274 /* { 275 syscallarg(int) pid; 276 syscallarg(int) pgid; 277 } */ 278 struct proc *p = l->l_proc; 279 pid_t targp, pgid; 280 281 if (SCARG(uap, pgid) < 0) 282 return EINVAL; 283 if ((targp = SCARG(uap, pid)) == 0) 284 targp = p->p_pid; 285 if ((pgid = SCARG(uap, pgid)) == 0) 286 pgid = targp; 287 288 return enterpgrp(p, targp, pgid, 0); 289 } 290 291 /* 292 * Set real, effective and saved uids to the requested values. 293 * non-root callers can only ever change uids to values that match 294 * one of the processes current uid values. 295 * This is further restricted by the flags argument. 296 */ 297 298 int 299 do_setresuid(struct lwp *l, uid_t r, uid_t e, uid_t sv, u_int flags) 300 { 301 struct proc *p = l->l_proc; 302 kauth_cred_t cred, ncred; 303 304 ncred = kauth_cred_alloc(); 305 306 /* Get a write lock on the process credential. */ 307 proc_crmod_enter(); 308 cred = p->p_cred; 309 310 /* 311 * Check that the new value is one of the allowed existing values, 312 * or that we have root privilege. 313 */ 314 if ((r != -1 315 && !((flags & ID_R_EQ_R) && r == kauth_cred_getuid(cred)) 316 && !((flags & ID_R_EQ_E) && r == kauth_cred_geteuid(cred)) 317 && !((flags & ID_R_EQ_S) && r == kauth_cred_getsvuid(cred))) || 318 (e != -1 319 && !((flags & ID_E_EQ_R) && e == kauth_cred_getuid(cred)) 320 && !((flags & ID_E_EQ_E) && e == kauth_cred_geteuid(cred)) 321 && !((flags & ID_E_EQ_S) && e == kauth_cred_getsvuid(cred))) || 322 (sv != -1 323 && !((flags & ID_S_EQ_R) && sv == kauth_cred_getuid(cred)) 324 && !((flags & ID_S_EQ_E) && sv == kauth_cred_geteuid(cred)) 325 && !((flags & ID_S_EQ_S) && sv == kauth_cred_getsvuid(cred)))) { 326 int error; 327 328 error = kauth_authorize_process(cred, KAUTH_PROCESS_SETID, 329 p, NULL, NULL, NULL); 330 if (error != 0) { 331 proc_crmod_leave(cred, ncred, false); 332 return error; 333 } 334 } 335 336 /* If nothing has changed, short circuit the request */ 337 if ((r == -1 || r == kauth_cred_getuid(cred)) 338 && (e == -1 || e == kauth_cred_geteuid(cred)) 339 && (sv == -1 || sv == kauth_cred_getsvuid(cred))) { 340 proc_crmod_leave(cred, ncred, false); 341 return 0; 342 } 343 344 kauth_cred_clone(cred, ncred); 345 346 if (r != -1 && r != kauth_cred_getuid(ncred)) { 347 /* Update count of processes for this user */ 348 (void)chgproccnt(kauth_cred_getuid(ncred), -1); 349 (void)chgproccnt(r, 1); 350 kauth_cred_setuid(ncred, r); 351 } 352 if (sv != -1) 353 kauth_cred_setsvuid(ncred, sv); 354 if (e != -1) 355 kauth_cred_seteuid(ncred, e); 356 357 /* Broadcast our credentials to the process and other LWPs. */ 358 proc_crmod_leave(ncred, cred, true); 359 360 return 0; 361 } 362 363 /* 364 * Set real, effective and saved gids to the requested values. 365 * non-root callers can only ever change gids to values that match 366 * one of the processes current gid values. 367 * This is further restricted by the flags argument. 368 */ 369 370 int 371 do_setresgid(struct lwp *l, gid_t r, gid_t e, gid_t sv, u_int flags) 372 { 373 struct proc *p = l->l_proc; 374 kauth_cred_t cred, ncred; 375 376 ncred = kauth_cred_alloc(); 377 378 /* Get a write lock on the process credential. */ 379 proc_crmod_enter(); 380 cred = p->p_cred; 381 382 /* 383 * check new value is one of the allowed existing values. 384 * otherwise, check if we have root privilege. 385 */ 386 if ((r != -1 387 && !((flags & ID_R_EQ_R) && r == kauth_cred_getgid(cred)) 388 && !((flags & ID_R_EQ_E) && r == kauth_cred_getegid(cred)) 389 && !((flags & ID_R_EQ_S) && r == kauth_cred_getsvgid(cred))) || 390 (e != -1 391 && !((flags & ID_E_EQ_R) && e == kauth_cred_getgid(cred)) 392 && !((flags & ID_E_EQ_E) && e == kauth_cred_getegid(cred)) 393 && !((flags & ID_E_EQ_S) && e == kauth_cred_getsvgid(cred))) || 394 (sv != -1 395 && !((flags & ID_S_EQ_R) && sv == kauth_cred_getgid(cred)) 396 && !((flags & ID_S_EQ_E) && sv == kauth_cred_getegid(cred)) 397 && !((flags & ID_S_EQ_S) && sv == kauth_cred_getsvgid(cred)))) { 398 int error; 399 400 error = kauth_authorize_process(cred, KAUTH_PROCESS_SETID, 401 p, NULL, NULL, NULL); 402 if (error != 0) { 403 proc_crmod_leave(cred, ncred, false); 404 return error; 405 } 406 } 407 408 /* If nothing has changed, short circuit the request */ 409 if ((r == -1 || r == kauth_cred_getgid(cred)) 410 && (e == -1 || e == kauth_cred_getegid(cred)) 411 && (sv == -1 || sv == kauth_cred_getsvgid(cred))) { 412 proc_crmod_leave(cred, ncred, false); 413 return 0; 414 } 415 416 kauth_cred_clone(cred, ncred); 417 418 if (r != -1) 419 kauth_cred_setgid(ncred, r); 420 if (sv != -1) 421 kauth_cred_setsvgid(ncred, sv); 422 if (e != -1) 423 kauth_cred_setegid(ncred, e); 424 425 /* Broadcast our credentials to the process and other LWPs. */ 426 proc_crmod_leave(ncred, cred, true); 427 428 return 0; 429 } 430 431 /* ARGSUSED */ 432 int 433 sys_setuid(struct lwp *l, const struct sys_setuid_args *uap, register_t *retval) 434 { 435 /* { 436 syscallarg(uid_t) uid; 437 } */ 438 uid_t uid = SCARG(uap, uid); 439 440 return do_setresuid(l, uid, uid, uid, 441 ID_R_EQ_R | ID_E_EQ_R | ID_S_EQ_R); 442 } 443 444 /* ARGSUSED */ 445 int 446 sys_seteuid(struct lwp *l, const struct sys_seteuid_args *uap, register_t *retval) 447 { 448 /* { 449 syscallarg(uid_t) euid; 450 } */ 451 452 return do_setresuid(l, -1, SCARG(uap, euid), -1, ID_E_EQ_R | ID_E_EQ_S); 453 } 454 455 int 456 sys_setreuid(struct lwp *l, const struct sys_setreuid_args *uap, register_t *retval) 457 { 458 /* { 459 syscallarg(uid_t) ruid; 460 syscallarg(uid_t) euid; 461 } */ 462 kauth_cred_t cred = l->l_cred; 463 uid_t ruid, euid, svuid; 464 465 ruid = SCARG(uap, ruid); 466 euid = SCARG(uap, euid); 467 468 if (ruid == -1) 469 ruid = kauth_cred_getuid(cred); 470 if (euid == -1) 471 euid = kauth_cred_geteuid(cred); 472 473 /* Saved uid is set to the new euid if the ruid changed */ 474 svuid = (ruid == kauth_cred_getuid(cred)) ? -1 : euid; 475 476 return do_setresuid(l, ruid, euid, svuid, 477 ID_R_EQ_R | ID_R_EQ_E | 478 ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S | 479 ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S); 480 } 481 482 /* ARGSUSED */ 483 int 484 sys_setgid(struct lwp *l, const struct sys_setgid_args *uap, register_t *retval) 485 { 486 /* { 487 syscallarg(gid_t) gid; 488 } */ 489 gid_t gid = SCARG(uap, gid); 490 491 return do_setresgid(l, gid, gid, gid, 492 ID_R_EQ_R | ID_E_EQ_R | ID_S_EQ_R); 493 } 494 495 /* ARGSUSED */ 496 int 497 sys_setegid(struct lwp *l, const struct sys_setegid_args *uap, register_t *retval) 498 { 499 /* { 500 syscallarg(gid_t) egid; 501 } */ 502 503 return do_setresgid(l, -1, SCARG(uap, egid), -1, ID_E_EQ_R | ID_E_EQ_S); 504 } 505 506 int 507 sys_setregid(struct lwp *l, const struct sys_setregid_args *uap, register_t *retval) 508 { 509 /* { 510 syscallarg(gid_t) rgid; 511 syscallarg(gid_t) egid; 512 } */ 513 kauth_cred_t cred = l->l_cred; 514 gid_t rgid, egid, svgid; 515 516 rgid = SCARG(uap, rgid); 517 egid = SCARG(uap, egid); 518 519 if (rgid == -1) 520 rgid = kauth_cred_getgid(cred); 521 if (egid == -1) 522 egid = kauth_cred_getegid(cred); 523 524 /* Saved gid is set to the new egid if the rgid changed */ 525 svgid = rgid == kauth_cred_getgid(cred) ? -1 : egid; 526 527 return do_setresgid(l, rgid, egid, svgid, 528 ID_R_EQ_R | ID_R_EQ_E | 529 ID_E_EQ_R | ID_E_EQ_E | ID_E_EQ_S | 530 ID_S_EQ_R | ID_S_EQ_E | ID_S_EQ_S); 531 } 532 533 int 534 sys_issetugid(struct lwp *l, const void *v, register_t *retval) 535 { 536 struct proc *p = l->l_proc; 537 538 /* 539 * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time, 540 * we use PK_SUGID because we consider changing the owners as 541 * "tainting" as well. 542 * This is significant for procs that start as root and "become" 543 * a user without an exec - programs cannot know *everything* 544 * that libc *might* have put in their data segment. 545 */ 546 *retval = (p->p_flag & PK_SUGID) != 0; 547 return (0); 548 } 549 550 /* ARGSUSED */ 551 int 552 sys_setgroups(struct lwp *l, const struct sys_setgroups_args *uap, register_t *retval) 553 { 554 /* { 555 syscallarg(int) gidsetsize; 556 syscallarg(const gid_t *) gidset; 557 } */ 558 kauth_cred_t ncred; 559 int error; 560 561 ncred = kauth_cred_alloc(); 562 error = kauth_cred_setgroups(ncred, SCARG(uap, gidset), 563 SCARG(uap, gidsetsize), -1, UIO_USERSPACE); 564 if (error != 0) { 565 kauth_cred_free(ncred); 566 return error; 567 } 568 569 return kauth_proc_setgroups(l, ncred); 570 } 571 572 /* 573 * Get login name, if available. 574 */ 575 /* ARGSUSED */ 576 int 577 sys___getlogin(struct lwp *l, const struct sys___getlogin_args *uap, register_t *retval) 578 { 579 /* { 580 syscallarg(char *) namebuf; 581 syscallarg(size_t) namelen; 582 } */ 583 struct proc *p = l->l_proc; 584 char login[sizeof(p->p_session->s_login)]; 585 int namelen = SCARG(uap, namelen); 586 587 if (namelen > sizeof(login)) 588 namelen = sizeof(login); 589 mutex_enter(proc_lock); 590 memcpy(login, p->p_session->s_login, namelen); 591 mutex_exit(proc_lock); 592 return (copyout(login, (void *)SCARG(uap, namebuf), namelen)); 593 } 594 595 /* 596 * Set login name. 597 */ 598 /* ARGSUSED */ 599 int 600 sys___setlogin(struct lwp *l, const struct sys___setlogin_args *uap, register_t *retval) 601 { 602 /* { 603 syscallarg(const char *) namebuf; 604 } */ 605 struct proc *p = l->l_proc; 606 struct session *sp; 607 char newname[sizeof sp->s_login + 1]; 608 int error; 609 610 if ((error = kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SETID, 611 p, NULL, NULL, NULL)) != 0) 612 return (error); 613 error = copyinstr(SCARG(uap, namebuf), &newname, sizeof newname, NULL); 614 if (error != 0) 615 return (error == ENAMETOOLONG ? EINVAL : error); 616 617 mutex_enter(proc_lock); 618 sp = p->p_session; 619 if (sp->s_flags & S_LOGIN_SET && p->p_pid != sp->s_sid && 620 strncmp(newname, sp->s_login, sizeof sp->s_login) != 0) 621 log(LOG_WARNING, "%s (pid %d) changing logname from " 622 "%.*s to %s\n", p->p_comm, p->p_pid, 623 (int)sizeof sp->s_login, sp->s_login, newname); 624 sp->s_flags |= S_LOGIN_SET; 625 strncpy(sp->s_login, newname, sizeof sp->s_login); 626 mutex_exit(proc_lock); 627 return (0); 628 } 629 630