| 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 1.15 2004/03/05 16:57:15 hsu 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/proc.h> |
| 55 | #include <sys/malloc.h> |
| 56 | #include <sys/pioctl.h> |
| 57 | #include <sys/resourcevar.h> |
| 58 | #include <sys/thread2.h> |
| 59 | #include <sys/jail.h> |
| 60 | |
| 61 | static MALLOC_DEFINE(M_CRED, "cred", "credentials"); |
| 62 | |
| 63 | /* |
| 64 | * NOT MP SAFE due to p_pptr access |
| 65 | */ |
| 66 | /* ARGSUSED */ |
| 67 | int |
| 68 | getpid(struct getpid_args *uap) |
| 69 | { |
| 70 | struct proc *p = curproc; |
| 71 | |
| 72 | uap->sysmsg_fds[0] = p->p_pid; |
| 73 | #if defined(COMPAT_43) || defined(COMPAT_SUNOS) |
| 74 | uap->sysmsg_fds[1] = p->p_pptr->p_pid; |
| 75 | #endif |
| 76 | return (0); |
| 77 | } |
| 78 | |
| 79 | /* ARGSUSED */ |
| 80 | int |
| 81 | getppid(struct getppid_args *uap) |
| 82 | { |
| 83 | struct proc *p = curproc; |
| 84 | |
| 85 | uap->sysmsg_result = p->p_pptr->p_pid; |
| 86 | return (0); |
| 87 | } |
| 88 | |
| 89 | /* |
| 90 | * Get process group ID; note that POSIX getpgrp takes no parameter |
| 91 | * |
| 92 | * MP SAFE |
| 93 | */ |
| 94 | int |
| 95 | getpgrp(struct getpgrp_args *uap) |
| 96 | { |
| 97 | struct proc *p = curproc; |
| 98 | |
| 99 | uap->sysmsg_result = p->p_pgrp->pg_id; |
| 100 | return (0); |
| 101 | } |
| 102 | |
| 103 | /* |
| 104 | * Get an arbitary pid's process group id |
| 105 | */ |
| 106 | int |
| 107 | getpgid(struct getpgid_args *uap) |
| 108 | { |
| 109 | struct proc *p = curproc; |
| 110 | struct proc *pt; |
| 111 | |
| 112 | pt = p; |
| 113 | if (uap->pid == 0) |
| 114 | goto found; |
| 115 | |
| 116 | if ((pt = pfind(uap->pid)) == 0) |
| 117 | return ESRCH; |
| 118 | found: |
| 119 | uap->sysmsg_result = pt->p_pgrp->pg_id; |
| 120 | return 0; |
| 121 | } |
| 122 | |
| 123 | /* |
| 124 | * Get an arbitary pid's session id. |
| 125 | */ |
| 126 | int |
| 127 | getsid(struct getsid_args *uap) |
| 128 | { |
| 129 | struct proc *p = curproc; |
| 130 | struct proc *pt; |
| 131 | |
| 132 | pt = p; |
| 133 | if (uap->pid == 0) |
| 134 | goto found; |
| 135 | |
| 136 | if ((pt = pfind(uap->pid)) == 0) |
| 137 | return ESRCH; |
| 138 | found: |
| 139 | uap->sysmsg_result = pt->p_session->s_sid; |
| 140 | return 0; |
| 141 | } |
| 142 | |
| 143 | |
| 144 | /* |
| 145 | * getuid() - MP SAFE |
| 146 | */ |
| 147 | /* ARGSUSED */ |
| 148 | int |
| 149 | getuid(struct getuid_args *uap) |
| 150 | { |
| 151 | struct proc *p = curproc; |
| 152 | |
| 153 | uap->sysmsg_fds[0] = p->p_ucred->cr_ruid; |
| 154 | #if defined(COMPAT_43) || defined(COMPAT_SUNOS) |
| 155 | uap->sysmsg_fds[1] = p->p_ucred->cr_uid; |
| 156 | #endif |
| 157 | return (0); |
| 158 | } |
| 159 | |
| 160 | /* |
| 161 | * geteuid() - MP SAFE |
| 162 | */ |
| 163 | /* ARGSUSED */ |
| 164 | int |
| 165 | geteuid(struct geteuid_args *uap) |
| 166 | { |
| 167 | struct proc *p = curproc; |
| 168 | |
| 169 | uap->sysmsg_result = p->p_ucred->cr_uid; |
| 170 | return (0); |
| 171 | } |
| 172 | |
| 173 | /* |
| 174 | * getgid() - MP SAFE |
| 175 | */ |
| 176 | /* ARGSUSED */ |
| 177 | int |
| 178 | getgid(struct getgid_args *uap) |
| 179 | { |
| 180 | struct proc *p = curproc; |
| 181 | |
| 182 | uap->sysmsg_fds[0] = p->p_ucred->cr_rgid; |
| 183 | #if defined(COMPAT_43) || defined(COMPAT_SUNOS) |
| 184 | uap->sysmsg_fds[1] = p->p_ucred->cr_groups[0]; |
| 185 | #endif |
| 186 | return (0); |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * Get effective group ID. The "egid" is groups[0], and could be obtained |
| 191 | * via getgroups. This syscall exists because it is somewhat painful to do |
| 192 | * correctly in a library function. |
| 193 | */ |
| 194 | /* ARGSUSED */ |
| 195 | int |
| 196 | getegid(struct getegid_args *uap) |
| 197 | { |
| 198 | struct proc *p = curproc; |
| 199 | |
| 200 | uap->sysmsg_result = p->p_ucred->cr_groups[0]; |
| 201 | return (0); |
| 202 | } |
| 203 | |
| 204 | int |
| 205 | getgroups(struct getgroups_args *uap) |
| 206 | { |
| 207 | struct proc *p = curproc; |
| 208 | struct ucred *cr; |
| 209 | u_int ngrp; |
| 210 | int error; |
| 211 | |
| 212 | if (p == NULL) /* API enforcement */ |
| 213 | return(EPERM); |
| 214 | cr = p->p_ucred; |
| 215 | |
| 216 | if ((ngrp = uap->gidsetsize) == 0) { |
| 217 | uap->sysmsg_result = cr->cr_ngroups; |
| 218 | return (0); |
| 219 | } |
| 220 | if (ngrp < cr->cr_ngroups) |
| 221 | return (EINVAL); |
| 222 | ngrp = cr->cr_ngroups; |
| 223 | if ((error = copyout((caddr_t)cr->cr_groups, |
| 224 | (caddr_t)uap->gidset, ngrp * sizeof(gid_t)))) |
| 225 | return (error); |
| 226 | uap->sysmsg_result = ngrp; |
| 227 | return (0); |
| 228 | } |
| 229 | |
| 230 | /* ARGSUSED */ |
| 231 | int |
| 232 | setsid(struct setsid_args *uap) |
| 233 | { |
| 234 | struct proc *p = curproc; |
| 235 | |
| 236 | if (p->p_pgid == p->p_pid || pgfind(p->p_pid)) { |
| 237 | return (EPERM); |
| 238 | } else { |
| 239 | (void)enterpgrp(p, p->p_pid, 1); |
| 240 | uap->sysmsg_result = p->p_pid; |
| 241 | return (0); |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | /* |
| 246 | * set process group (setpgid/old setpgrp) |
| 247 | * |
| 248 | * caller does setpgid(targpid, targpgid) |
| 249 | * |
| 250 | * pid must be caller or child of caller (ESRCH) |
| 251 | * if a child |
| 252 | * pid must be in same session (EPERM) |
| 253 | * pid can't have done an exec (EACCES) |
| 254 | * if pgid != pid |
| 255 | * there must exist some pid in same session having pgid (EPERM) |
| 256 | * pid must not be session leader (EPERM) |
| 257 | */ |
| 258 | /* ARGSUSED */ |
| 259 | int |
| 260 | setpgid(struct setpgid_args *uap) |
| 261 | { |
| 262 | struct proc *curp = curproc; |
| 263 | struct proc *targp; /* target process */ |
| 264 | struct pgrp *pgrp; /* target pgrp */ |
| 265 | |
| 266 | if (uap->pgid < 0) |
| 267 | return (EINVAL); |
| 268 | if (uap->pid != 0 && uap->pid != curp->p_pid) { |
| 269 | if ((targp = pfind(uap->pid)) == 0 || !inferior(targp)) |
| 270 | return (ESRCH); |
| 271 | if (targp->p_pgrp == NULL || targp->p_session != curp->p_session) |
| 272 | return (EPERM); |
| 273 | if (targp->p_flag & P_EXEC) |
| 274 | return (EACCES); |
| 275 | } else |
| 276 | targp = curp; |
| 277 | if (SESS_LEADER(targp)) |
| 278 | return (EPERM); |
| 279 | if (uap->pgid == 0) |
| 280 | uap->pgid = targp->p_pid; |
| 281 | else if (uap->pgid != targp->p_pid) |
| 282 | if ((pgrp = pgfind(uap->pgid)) == 0 || |
| 283 | pgrp->pg_session != curp->p_session) |
| 284 | return (EPERM); |
| 285 | return (enterpgrp(targp, uap->pgid, 0)); |
| 286 | } |
| 287 | |
| 288 | /* |
| 289 | * Use the clause in B.4.2.2 that allows setuid/setgid to be 4.2/4.3BSD |
| 290 | * compatible. It says that setting the uid/gid to euid/egid is a special |
| 291 | * case of "appropriate privilege". Once the rules are expanded out, this |
| 292 | * basically means that setuid(nnn) sets all three id's, in all permitted |
| 293 | * cases unless _POSIX_SAVED_IDS is enabled. In that case, setuid(getuid()) |
| 294 | * does not set the saved id - this is dangerous for traditional BSD |
| 295 | * programs. For this reason, we *really* do not want to set |
| 296 | * _POSIX_SAVED_IDS and do not want to clear POSIX_APPENDIX_B_4_2_2. |
| 297 | */ |
| 298 | #define POSIX_APPENDIX_B_4_2_2 |
| 299 | |
| 300 | /* ARGSUSED */ |
| 301 | int |
| 302 | setuid(struct setuid_args *uap) |
| 303 | { |
| 304 | struct proc *p = curproc; |
| 305 | struct ucred *cr; |
| 306 | uid_t uid; |
| 307 | int error; |
| 308 | |
| 309 | if (p == NULL) /* API enforcement */ |
| 310 | return(EPERM); |
| 311 | cr = p->p_ucred; |
| 312 | |
| 313 | /* |
| 314 | * See if we have "permission" by POSIX 1003.1 rules. |
| 315 | * |
| 316 | * Note that setuid(geteuid()) is a special case of |
| 317 | * "appropriate privileges" in appendix B.4.2.2. We need |
| 318 | * to use this clause to be compatible with traditional BSD |
| 319 | * semantics. Basically, it means that "setuid(xx)" sets all |
| 320 | * three id's (assuming you have privs). |
| 321 | * |
| 322 | * Notes on the logic. We do things in three steps. |
| 323 | * 1: We determine if the euid is going to change, and do EPERM |
| 324 | * right away. We unconditionally change the euid later if this |
| 325 | * test is satisfied, simplifying that part of the logic. |
| 326 | * 2: We determine if the real and/or saved uid's are going to |
| 327 | * change. Determined by compile options. |
| 328 | * 3: Change euid last. (after tests in #2 for "appropriate privs") |
| 329 | */ |
| 330 | uid = uap->uid; |
| 331 | if (uid != cr->cr_ruid && /* allow setuid(getuid()) */ |
| 332 | #ifdef _POSIX_SAVED_IDS |
| 333 | uid != crc->cr_svuid && /* allow setuid(saved gid) */ |
| 334 | #endif |
| 335 | #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */ |
| 336 | uid != cr->cr_uid && /* allow setuid(geteuid()) */ |
| 337 | #endif |
| 338 | (error = suser_cred(cr, PRISON_ROOT))) |
| 339 | return (error); |
| 340 | |
| 341 | #ifdef _POSIX_SAVED_IDS |
| 342 | /* |
| 343 | * Do we have "appropriate privileges" (are we root or uid == euid) |
| 344 | * If so, we are changing the real uid and/or saved uid. |
| 345 | */ |
| 346 | if ( |
| 347 | #ifdef POSIX_APPENDIX_B_4_2_2 /* Use the clause from B.4.2.2 */ |
| 348 | uid == cr->cr_uid || |
| 349 | #endif |
| 350 | suser_cred(cr, PRISON_ROOT) == 0) /* we are using privs */ |
| 351 | #endif |
| 352 | { |
| 353 | /* |
| 354 | * Set the real uid and transfer proc count to new user. |
| 355 | */ |
| 356 | if (uid != cr->cr_ruid) { |
| 357 | change_ruid(uid); |
| 358 | setsugid(); |
| 359 | } |
| 360 | /* |
| 361 | * Set saved uid |
| 362 | * |
| 363 | * XXX always set saved uid even if not _POSIX_SAVED_IDS, as |
| 364 | * the security of seteuid() depends on it. B.4.2.2 says it |
| 365 | * is important that we should do this. |
| 366 | */ |
| 367 | if (cr->cr_svuid != uid) { |
| 368 | cr = cratom(&p->p_ucred); |
| 369 | cr->cr_svuid = uid; |
| 370 | setsugid(); |
| 371 | } |
| 372 | } |
| 373 | |
| 374 | /* |
| 375 | * In all permitted cases, we are changing the euid. |
| 376 | * Copy credentials so other references do not see our changes. |
| 377 | */ |
| 378 | if (cr->cr_uid != uid) { |
| 379 | change_euid(uid); |
| 380 | setsugid(); |
| 381 | } |
| 382 | return (0); |
| 383 | } |
| 384 | |
| 385 | /* ARGSUSED */ |
| 386 | int |
| 387 | seteuid(struct seteuid_args *uap) |
| 388 | { |
| 389 | struct proc *p = curproc; |
| 390 | struct ucred *cr; |
| 391 | uid_t euid; |
| 392 | int error; |
| 393 | |
| 394 | if (p == NULL) /* API enforcement */ |
| 395 | return(EPERM); |
| 396 | |
| 397 | cr = p->p_ucred; |
| 398 | euid = uap->euid; |
| 399 | if (euid != cr->cr_ruid && /* allow seteuid(getuid()) */ |
| 400 | euid != cr->cr_svuid && /* allow seteuid(saved uid) */ |
| 401 | (error = suser_cred(cr, PRISON_ROOT))) |
| 402 | return (error); |
| 403 | /* |
| 404 | * Everything's okay, do it. Copy credentials so other references do |
| 405 | * not see our changes. |
| 406 | */ |
| 407 | if (cr->cr_uid != euid) { |
| 408 | change_euid(euid); |
| 409 | setsugid(); |
| 410 | } |
| 411 | return (0); |
| 412 | } |
| 413 | |
| 414 | /* ARGSUSED */ |
| 415 | int |
| 416 | setgid(struct setgid_args *uap) |
| 417 | { |
| 418 | struct proc *p = curproc; |
| 419 | struct ucred *cr; |
| 420 | gid_t gid; |
| 421 | int error; |
| 422 | |
| 423 | if (p == NULL) /* API enforcement */ |
| 424 | return(EPERM); |
| 425 | cr = p->p_ucred; |
| 426 | |
| 427 | /* |
| 428 | * See if we have "permission" by POSIX 1003.1 rules. |
| 429 | * |
| 430 | * Note that setgid(getegid()) is a special case of |
| 431 | * "appropriate privileges" in appendix B.4.2.2. We need |
| 432 | * to use this clause to be compatible with traditional BSD |
| 433 | * semantics. Basically, it means that "setgid(xx)" sets all |
| 434 | * three id's (assuming you have privs). |
| 435 | * |
| 436 | * For notes on the logic here, see setuid() above. |
| 437 | */ |
| 438 | gid = uap->gid; |
| 439 | if (gid != cr->cr_rgid && /* allow setgid(getgid()) */ |
| 440 | #ifdef _POSIX_SAVED_IDS |
| 441 | gid != cr->cr_svgid && /* allow setgid(saved gid) */ |
| 442 | #endif |
| 443 | #ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */ |
| 444 | gid != cr->cr_groups[0] && /* allow setgid(getegid()) */ |
| 445 | #endif |
| 446 | (error = suser_cred(cr, PRISON_ROOT))) |
| 447 | return (error); |
| 448 | |
| 449 | #ifdef _POSIX_SAVED_IDS |
| 450 | /* |
| 451 | * Do we have "appropriate privileges" (are we root or gid == egid) |
| 452 | * If so, we are changing the real uid and saved gid. |
| 453 | */ |
| 454 | if ( |
| 455 | #ifdef POSIX_APPENDIX_B_4_2_2 /* use the clause from B.4.2.2 */ |
| 456 | gid == cr->cr_groups[0] || |
| 457 | #endif |
| 458 | suser_cred(cr, PRISON_ROOT) == 0) /* we are using privs */ |
| 459 | #endif |
| 460 | { |
| 461 | /* |
| 462 | * Set real gid |
| 463 | */ |
| 464 | if (cr->cr_rgid != gid) { |
| 465 | cr = cratom(&p->p_ucred); |
| 466 | cr->cr_rgid = gid; |
| 467 | setsugid(); |
| 468 | } |
| 469 | /* |
| 470 | * Set saved gid |
| 471 | * |
| 472 | * XXX always set saved gid even if not _POSIX_SAVED_IDS, as |
| 473 | * the security of setegid() depends on it. B.4.2.2 says it |
| 474 | * is important that we should do this. |
| 475 | */ |
| 476 | if (cr->cr_svgid != gid) { |
| 477 | cr = cratom(&p->p_ucred); |
| 478 | cr->cr_svgid = gid; |
| 479 | setsugid(); |
| 480 | } |
| 481 | } |
| 482 | /* |
| 483 | * In all cases permitted cases, we are changing the egid. |
| 484 | * Copy credentials so other references do not see our changes. |
| 485 | */ |
| 486 | if (cr->cr_groups[0] != gid) { |
| 487 | cr = cratom(&p->p_ucred); |
| 488 | cr->cr_groups[0] = gid; |
| 489 | setsugid(); |
| 490 | } |
| 491 | return (0); |
| 492 | } |
| 493 | |
| 494 | /* ARGSUSED */ |
| 495 | int |
| 496 | setegid(struct setegid_args *uap) |
| 497 | { |
| 498 | struct proc *p = curproc; |
| 499 | struct ucred *cr; |
| 500 | gid_t egid; |
| 501 | int error; |
| 502 | |
| 503 | if (p == NULL) /* API enforcement */ |
| 504 | return(EPERM); |
| 505 | cr = p->p_ucred; |
| 506 | |
| 507 | egid = uap->egid; |
| 508 | if (egid != cr->cr_rgid && /* allow setegid(getgid()) */ |
| 509 | egid != cr->cr_svgid && /* allow setegid(saved gid) */ |
| 510 | (error = suser_cred(cr, PRISON_ROOT))) |
| 511 | return (error); |
| 512 | if (cr->cr_groups[0] != egid) { |
| 513 | cr = cratom(&p->p_ucred); |
| 514 | cr->cr_groups[0] = egid; |
| 515 | setsugid(); |
| 516 | } |
| 517 | return (0); |
| 518 | } |
| 519 | |
| 520 | /* ARGSUSED */ |
| 521 | int |
| 522 | setgroups(struct setgroups_args *uap) |
| 523 | { |
| 524 | struct proc *p = curproc; |
| 525 | struct ucred *cr; |
| 526 | u_int ngrp; |
| 527 | int error; |
| 528 | |
| 529 | if (p == NULL) /* API enforcement */ |
| 530 | return(EPERM); |
| 531 | cr = p->p_ucred; |
| 532 | |
| 533 | if ((error = suser_cred(cr, PRISON_ROOT))) |
| 534 | return (error); |
| 535 | ngrp = uap->gidsetsize; |
| 536 | if (ngrp > NGROUPS) |
| 537 | return (EINVAL); |
| 538 | /* |
| 539 | * XXX A little bit lazy here. We could test if anything has |
| 540 | * changed before cratom() and setting P_SUGID. |
| 541 | */ |
| 542 | cr = cratom(&p->p_ucred); |
| 543 | if (ngrp < 1) { |
| 544 | /* |
| 545 | * setgroups(0, NULL) is a legitimate way of clearing the |
| 546 | * groups vector on non-BSD systems (which generally do not |
| 547 | * have the egid in the groups[0]). We risk security holes |
| 548 | * when running non-BSD software if we do not do the same. |
| 549 | */ |
| 550 | cr->cr_ngroups = 1; |
| 551 | } else { |
| 552 | if ((error = copyin((caddr_t)uap->gidset, |
| 553 | (caddr_t)cr->cr_groups, ngrp * sizeof(gid_t)))) |
| 554 | return (error); |
| 555 | cr->cr_ngroups = ngrp; |
| 556 | } |
| 557 | setsugid(); |
| 558 | return (0); |
| 559 | } |
| 560 | |
| 561 | /* ARGSUSED */ |
| 562 | int |
| 563 | setreuid(struct setreuid_args *uap) |
| 564 | { |
| 565 | struct proc *p = curproc; |
| 566 | struct ucred *cr; |
| 567 | uid_t ruid, euid; |
| 568 | int error; |
| 569 | |
| 570 | if (p == NULL) /* API enforcement */ |
| 571 | return(EPERM); |
| 572 | cr = p->p_ucred; |
| 573 | |
| 574 | ruid = uap->ruid; |
| 575 | euid = uap->euid; |
| 576 | if (((ruid != (uid_t)-1 && ruid != cr->cr_ruid && ruid != cr->cr_svuid) || |
| 577 | (euid != (uid_t)-1 && euid != cr->cr_uid && |
| 578 | euid != cr->cr_ruid && euid != cr->cr_svuid)) && |
| 579 | (error = suser_cred(cr, PRISON_ROOT)) != 0) |
| 580 | return (error); |
| 581 | |
| 582 | if (euid != (uid_t)-1 && cr->cr_uid != euid) { |
| 583 | change_euid(euid); |
| 584 | setsugid(); |
| 585 | } |
| 586 | if (ruid != (uid_t)-1 && cr->cr_ruid != ruid) { |
| 587 | change_ruid(ruid); |
| 588 | setsugid(); |
| 589 | } |
| 590 | if ((ruid != (uid_t)-1 || cr->cr_uid != cr->cr_ruid) && |
| 591 | cr->cr_svuid != cr->cr_uid) { |
| 592 | cr = cratom(&p->p_ucred); |
| 593 | cr->cr_svuid = cr->cr_uid; |
| 594 | setsugid(); |
| 595 | } |
| 596 | return (0); |
| 597 | } |
| 598 | |
| 599 | /* ARGSUSED */ |
| 600 | int |
| 601 | setregid(struct setregid_args *uap) |
| 602 | { |
| 603 | struct proc *p = curproc; |
| 604 | struct ucred *cr; |
| 605 | gid_t rgid, egid; |
| 606 | int error; |
| 607 | |
| 608 | if (p == NULL) /* API enforcement */ |
| 609 | return(EPERM); |
| 610 | cr = p->p_ucred; |
| 611 | |
| 612 | rgid = uap->rgid; |
| 613 | egid = uap->egid; |
| 614 | if (((rgid != (gid_t)-1 && rgid != cr->cr_rgid && rgid != cr->cr_svgid) || |
| 615 | (egid != (gid_t)-1 && egid != cr->cr_groups[0] && |
| 616 | egid != cr->cr_rgid && egid != cr->cr_svgid)) && |
| 617 | (error = suser_cred(cr, PRISON_ROOT)) != 0) |
| 618 | return (error); |
| 619 | |
| 620 | if (egid != (gid_t)-1 && cr->cr_groups[0] != egid) { |
| 621 | cr = cratom(&p->p_ucred); |
| 622 | cr->cr_groups[0] = egid; |
| 623 | setsugid(); |
| 624 | } |
| 625 | if (rgid != (gid_t)-1 && cr->cr_rgid != rgid) { |
| 626 | cr = cratom(&p->p_ucred); |
| 627 | cr->cr_rgid = rgid; |
| 628 | setsugid(); |
| 629 | } |
| 630 | if ((rgid != (gid_t)-1 || cr->cr_groups[0] != cr->cr_rgid) && |
| 631 | cr->cr_svgid != cr->cr_groups[0]) { |
| 632 | cr = cratom(&p->p_ucred); |
| 633 | cr->cr_svgid = cr->cr_groups[0]; |
| 634 | setsugid(); |
| 635 | } |
| 636 | return (0); |
| 637 | } |
| 638 | |
| 639 | /* |
| 640 | * setresuid(ruid, euid, suid) is like setreuid except control over the |
| 641 | * saved uid is explicit. |
| 642 | */ |
| 643 | |
| 644 | /* ARGSUSED */ |
| 645 | int |
| 646 | setresuid(struct setresuid_args *uap) |
| 647 | { |
| 648 | struct proc *p = curproc; |
| 649 | struct ucred *cr; |
| 650 | uid_t ruid, euid, suid; |
| 651 | int error; |
| 652 | |
| 653 | cr = p->p_ucred; |
| 654 | ruid = uap->ruid; |
| 655 | euid = uap->euid; |
| 656 | suid = uap->suid; |
| 657 | if (((ruid != (uid_t)-1 && ruid != cr->cr_ruid && ruid != cr->cr_svuid && |
| 658 | ruid != cr->cr_uid) || |
| 659 | (euid != (uid_t)-1 && euid != cr->cr_ruid && euid != cr->cr_svuid && |
| 660 | euid != cr->cr_uid) || |
| 661 | (suid != (uid_t)-1 && suid != cr->cr_ruid && suid != cr->cr_svuid && |
| 662 | suid != cr->cr_uid)) && |
| 663 | (error = suser_cred(cr, PRISON_ROOT)) != 0) |
| 664 | return (error); |
| 665 | if (euid != (uid_t)-1 && cr->cr_uid != euid) { |
| 666 | change_euid(euid); |
| 667 | setsugid(); |
| 668 | } |
| 669 | if (ruid != (uid_t)-1 && cr->cr_ruid != ruid) { |
| 670 | change_ruid(ruid); |
| 671 | setsugid(); |
| 672 | } |
| 673 | if (suid != (uid_t)-1 && cr->cr_svuid != suid) { |
| 674 | cr = cratom(&p->p_ucred); |
| 675 | cr->cr_svuid = suid; |
| 676 | setsugid(); |
| 677 | } |
| 678 | return (0); |
| 679 | } |
| 680 | |
| 681 | /* |
| 682 | * setresgid(rgid, egid, sgid) is like setregid except control over the |
| 683 | * saved gid is explicit. |
| 684 | */ |
| 685 | |
| 686 | /* ARGSUSED */ |
| 687 | int |
| 688 | setresgid(struct setresgid_args *uap) |
| 689 | { |
| 690 | struct proc *p = curproc; |
| 691 | struct ucred *cr; |
| 692 | gid_t rgid, egid, sgid; |
| 693 | int error; |
| 694 | |
| 695 | cr = p->p_ucred; |
| 696 | rgid = uap->rgid; |
| 697 | egid = uap->egid; |
| 698 | sgid = uap->sgid; |
| 699 | if (((rgid != (gid_t)-1 && rgid != cr->cr_rgid && rgid != cr->cr_svgid && |
| 700 | rgid != cr->cr_groups[0]) || |
| 701 | (egid != (gid_t)-1 && egid != cr->cr_rgid && egid != cr->cr_svgid && |
| 702 | egid != cr->cr_groups[0]) || |
| 703 | (sgid != (gid_t)-1 && sgid != cr->cr_rgid && sgid != cr->cr_svgid && |
| 704 | sgid != cr->cr_groups[0])) && |
| 705 | (error = suser_cred(cr, PRISON_ROOT)) != 0) |
| 706 | return (error); |
| 707 | |
| 708 | if (egid != (gid_t)-1 && cr->cr_groups[0] != egid) { |
| 709 | cr = cratom(&p->p_ucred); |
| 710 | cr->cr_groups[0] = egid; |
| 711 | setsugid(); |
| 712 | } |
| 713 | if (rgid != (gid_t)-1 && cr->cr_rgid != rgid) { |
| 714 | cr = cratom(&p->p_ucred); |
| 715 | cr->cr_rgid = rgid; |
| 716 | setsugid(); |
| 717 | } |
| 718 | if (sgid != (gid_t)-1 && cr->cr_svgid != sgid) { |
| 719 | cr = cratom(&p->p_ucred); |
| 720 | cr->cr_svgid = sgid; |
| 721 | setsugid(); |
| 722 | } |
| 723 | return (0); |
| 724 | } |
| 725 | |
| 726 | /* ARGSUSED */ |
| 727 | int |
| 728 | getresuid(struct getresuid_args *uap) |
| 729 | { |
| 730 | struct proc *p = curproc; |
| 731 | struct ucred *cr = p->p_ucred; |
| 732 | int error1 = 0, error2 = 0, error3 = 0; |
| 733 | |
| 734 | if (uap->ruid) |
| 735 | error1 = copyout((caddr_t)&cr->cr_ruid, |
| 736 | (caddr_t)uap->ruid, sizeof(cr->cr_ruid)); |
| 737 | if (uap->euid) |
| 738 | error2 = copyout((caddr_t)&cr->cr_uid, |
| 739 | (caddr_t)uap->euid, sizeof(cr->cr_uid)); |
| 740 | if (uap->suid) |
| 741 | error3 = copyout((caddr_t)&cr->cr_svuid, |
| 742 | (caddr_t)uap->suid, sizeof(cr->cr_svuid)); |
| 743 | return error1 ? error1 : (error2 ? error2 : error3); |
| 744 | } |
| 745 | |
| 746 | /* ARGSUSED */ |
| 747 | int |
| 748 | getresgid(struct getresgid_args *uap) |
| 749 | { |
| 750 | struct proc *p = curproc; |
| 751 | struct ucred *cr = p->p_ucred; |
| 752 | int error1 = 0, error2 = 0, error3 = 0; |
| 753 | |
| 754 | if (uap->rgid) |
| 755 | error1 = copyout((caddr_t)&cr->cr_rgid, |
| 756 | (caddr_t)uap->rgid, sizeof(cr->cr_rgid)); |
| 757 | if (uap->egid) |
| 758 | error2 = copyout((caddr_t)&cr->cr_groups[0], |
| 759 | (caddr_t)uap->egid, sizeof(cr->cr_groups[0])); |
| 760 | if (uap->sgid) |
| 761 | error3 = copyout((caddr_t)&cr->cr_svgid, |
| 762 | (caddr_t)uap->sgid, sizeof(cr->cr_svgid)); |
| 763 | return error1 ? error1 : (error2 ? error2 : error3); |
| 764 | } |
| 765 | |
| 766 | |
| 767 | /* ARGSUSED */ |
| 768 | int |
| 769 | issetugid(struct issetugid_args *uap) |
| 770 | { |
| 771 | struct proc *p = curproc; |
| 772 | /* |
| 773 | * Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time, |
| 774 | * we use P_SUGID because we consider changing the owners as |
| 775 | * "tainting" as well. |
| 776 | * This is significant for procs that start as root and "become" |
| 777 | * a user without an exec - programs cannot know *everything* |
| 778 | * that libc *might* have put in their data segment. |
| 779 | */ |
| 780 | uap->sysmsg_result = (p->p_flag & P_SUGID) ? 1 : 0; |
| 781 | return (0); |
| 782 | } |
| 783 | |
| 784 | /* |
| 785 | * Check if gid is a member of the group set. |
| 786 | */ |
| 787 | int |
| 788 | groupmember(gid_t gid, struct ucred *cred) |
| 789 | { |
| 790 | gid_t *gp; |
| 791 | gid_t *egp; |
| 792 | |
| 793 | egp = &(cred->cr_groups[cred->cr_ngroups]); |
| 794 | for (gp = cred->cr_groups; gp < egp; gp++) { |
| 795 | if (*gp == gid) |
| 796 | return (1); |
| 797 | } |
| 798 | return (0); |
| 799 | } |
| 800 | |
| 801 | /* |
| 802 | * Test whether the specified credentials imply "super-user" |
| 803 | * privilege; if so, and we have accounting info, set the flag |
| 804 | * indicating use of super-powers. A kernel thread without a process |
| 805 | * context is assumed to have super user capabilities. In situations |
| 806 | * where the caller always expect a cred to exist, the cred should be |
| 807 | * passed separately and suser_cred()should be used instead of suser(). |
| 808 | * |
| 809 | * Returns 0 or error. |
| 810 | */ |
| 811 | int |
| 812 | suser(struct thread *td) |
| 813 | { |
| 814 | struct proc *p = td->td_proc; |
| 815 | |
| 816 | if (p != NULL) { |
| 817 | return suser_cred(p->p_ucred, 0); |
| 818 | } else { |
| 819 | return (0); |
| 820 | } |
| 821 | } |
| 822 | |
| 823 | /* |
| 824 | * A non-null credential is expected unless NULL_CRED_OKAY is set. |
| 825 | */ |
| 826 | int |
| 827 | suser_cred(struct ucred *cred, int flag) |
| 828 | { |
| 829 | KASSERT(cred != NULL || flag & NULL_CRED_OKAY, |
| 830 | ("suser_cred: NULL cred!")); |
| 831 | |
| 832 | if (cred == NULL) { |
| 833 | if (flag & NULL_CRED_OKAY) |
| 834 | return (0); |
| 835 | else |
| 836 | return (EPERM); |
| 837 | } |
| 838 | if (cred->cr_uid != 0) |
| 839 | return (EPERM); |
| 840 | if (cred->cr_prison && !(flag & PRISON_ROOT)) |
| 841 | return (EPERM); |
| 842 | /* NOTE: accounting for suser access (p_acflag/ASU) removed */ |
| 843 | return (0); |
| 844 | } |
| 845 | |
| 846 | /* |
| 847 | * Return zero if p1 can fondle p2, return errno (EPERM/ESRCH) otherwise. |
| 848 | */ |
| 849 | int |
| 850 | p_trespass(struct ucred *cr1, struct ucred *cr2) |
| 851 | { |
| 852 | if (cr1 == cr2) |
| 853 | return (0); |
| 854 | if (!PRISON_CHECK(cr1, cr2)) |
| 855 | return (ESRCH); |
| 856 | if (cr1->cr_ruid == cr2->cr_ruid) |
| 857 | return (0); |
| 858 | if (cr1->cr_uid == cr2->cr_ruid) |
| 859 | return (0); |
| 860 | if (cr1->cr_ruid == cr2->cr_uid) |
| 861 | return (0); |
| 862 | if (cr1->cr_uid == cr2->cr_uid) |
| 863 | return (0); |
| 864 | if (suser_cred(cr1, PRISON_ROOT) == 0) |
| 865 | return (0); |
| 866 | return (EPERM); |
| 867 | } |
| 868 | |
| 869 | /* |
| 870 | * Allocate a zeroed cred structure. |
| 871 | */ |
| 872 | struct ucred * |
| 873 | crget() |
| 874 | { |
| 875 | struct ucred *cr; |
| 876 | |
| 877 | MALLOC(cr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK); |
| 878 | bzero((caddr_t)cr, sizeof(*cr)); |
| 879 | cr->cr_ref = 1; |
| 880 | return (cr); |
| 881 | } |
| 882 | |
| 883 | /* |
| 884 | * Claim another reference to a ucred structure. Can be used with special |
| 885 | * creds. |
| 886 | */ |
| 887 | struct ucred * |
| 888 | crhold(struct ucred *cr) |
| 889 | { |
| 890 | if (cr != NOCRED && cr != FSCRED) |
| 891 | cr->cr_ref++; |
| 892 | return(cr); |
| 893 | } |
| 894 | |
| 895 | /* |
| 896 | * Free a cred structure. |
| 897 | * Throws away space when ref count gets to 0. |
| 898 | * MPSAFE |
| 899 | */ |
| 900 | void |
| 901 | crfree(struct ucred *cr) |
| 902 | { |
| 903 | /* Protect crfree() as a critical section as there |
| 904 | * appears to be a crfree race which can occur on |
| 905 | * SMP systems. |
| 906 | */ |
| 907 | crit_enter(); |
| 908 | if (cr->cr_ref == 0) |
| 909 | panic("Freeing already free credential! %p", cr); |
| 910 | |
| 911 | if (--cr->cr_ref == 0) { |
| 912 | /* |
| 913 | * Some callers of crget(), such as nfs_statfs(), |
| 914 | * allocate a temporary credential, but don't |
| 915 | * allocate a uidinfo structure. |
| 916 | */ |
| 917 | if (cr->cr_uidinfo != NULL) { |
| 918 | uidrop(cr->cr_uidinfo); |
| 919 | cr->cr_uidinfo = NULL; |
| 920 | } |
| 921 | if (cr->cr_ruidinfo != NULL) { |
| 922 | uidrop(cr->cr_ruidinfo); |
| 923 | cr->cr_ruidinfo = NULL; |
| 924 | } |
| 925 | |
| 926 | /* |
| 927 | * Destroy empty prisons |
| 928 | */ |
| 929 | if (cr->cr_prison && !--cr->cr_prison->pr_ref) { |
| 930 | if (cr->cr_prison->pr_linux != NULL) |
| 931 | FREE(cr->cr_prison->pr_linux, M_PRISON); |
| 932 | FREE(cr->cr_prison, M_PRISON); |
| 933 | } |
| 934 | cr->cr_prison = NULL; /* safety */ |
| 935 | |
| 936 | FREE((caddr_t)cr, M_CRED); |
| 937 | } |
| 938 | crit_exit(); |
| 939 | } |
| 940 | |
| 941 | /* |
| 942 | * Atomize a cred structure so it can be modified without polluting |
| 943 | * other references to it. |
| 944 | */ |
| 945 | struct ucred * |
| 946 | cratom(struct ucred **pcr) |
| 947 | { |
| 948 | struct ucred *oldcr; |
| 949 | struct ucred *newcr; |
| 950 | |
| 951 | oldcr = *pcr; |
| 952 | if (oldcr->cr_ref == 1) |
| 953 | return (oldcr); |
| 954 | newcr = crget(); |
| 955 | *newcr = *oldcr; |
| 956 | if (newcr->cr_uidinfo) |
| 957 | uihold(newcr->cr_uidinfo); |
| 958 | if (newcr->cr_ruidinfo) |
| 959 | uihold(newcr->cr_ruidinfo); |
| 960 | if (newcr->cr_prison) |
| 961 | ++newcr->cr_prison->pr_ref; |
| 962 | newcr->cr_ref = 1; |
| 963 | crfree(oldcr); |
| 964 | *pcr = newcr; |
| 965 | return (newcr); |
| 966 | } |
| 967 | |
| 968 | #if 0 /* no longer used but keep around for a little while */ |
| 969 | /* |
| 970 | * Copy cred structure to a new one and free the old one. |
| 971 | */ |
| 972 | struct ucred * |
| 973 | crcopy(struct ucred *cr) |
| 974 | { |
| 975 | struct ucred *newcr; |
| 976 | |
| 977 | if (cr->cr_ref == 1) |
| 978 | return (cr); |
| 979 | newcr = crget(); |
| 980 | *newcr = *cr; |
| 981 | if (newcr->cr_uidinfo) |
| 982 | uihold(newcr->cr_uidinfo); |
| 983 | if (newcr->cr_ruidinfo) |
| 984 | uihold(newcr->cr_ruidinfo); |
| 985 | if (newcr->cr_prison) |
| 986 | ++newcr->cr_prison->pr_ref; |
| 987 | newcr->cr_ref = 1; |
| 988 | crfree(cr); |
| 989 | return (newcr); |
| 990 | } |
| 991 | #endif |
| 992 | |
| 993 | /* |
| 994 | * Dup cred struct to a new held one. |
| 995 | */ |
| 996 | struct ucred * |
| 997 | crdup(cr) |
| 998 | struct ucred *cr; |
| 999 | { |
| 1000 | struct ucred *newcr; |
| 1001 | |
| 1002 | newcr = crget(); |
| 1003 | *newcr = *cr; |
| 1004 | if (newcr->cr_uidinfo) |
| 1005 | uihold(newcr->cr_uidinfo); |
| 1006 | if (newcr->cr_ruidinfo) |
| 1007 | uihold(newcr->cr_ruidinfo); |
| 1008 | if (newcr->cr_prison) |
| 1009 | ++newcr->cr_prison->pr_ref; |
| 1010 | newcr->cr_ref = 1; |
| 1011 | return (newcr); |
| 1012 | } |
| 1013 | |
| 1014 | /* |
| 1015 | * Fill in a struct xucred based on a struct ucred. |
| 1016 | */ |
| 1017 | void |
| 1018 | cru2x(cr, xcr) |
| 1019 | struct ucred *cr; |
| 1020 | struct xucred *xcr; |
| 1021 | { |
| 1022 | |
| 1023 | bzero(xcr, sizeof(*xcr)); |
| 1024 | xcr->cr_version = XUCRED_VERSION; |
| 1025 | xcr->cr_uid = cr->cr_uid; |
| 1026 | xcr->cr_ngroups = cr->cr_ngroups; |
| 1027 | bcopy(cr->cr_groups, xcr->cr_groups, sizeof(cr->cr_groups)); |
| 1028 | } |
| 1029 | |
| 1030 | /* |
| 1031 | * Get login name, if available. |
| 1032 | */ |
| 1033 | /* ARGSUSED */ |
| 1034 | int |
| 1035 | getlogin(struct getlogin_args *uap) |
| 1036 | { |
| 1037 | struct proc *p = curproc; |
| 1038 | |
| 1039 | if (uap->namelen > MAXLOGNAME) |
| 1040 | uap->namelen = MAXLOGNAME; |
| 1041 | return (copyout((caddr_t) p->p_pgrp->pg_session->s_login, |
| 1042 | (caddr_t) uap->namebuf, uap->namelen)); |
| 1043 | } |
| 1044 | |
| 1045 | /* |
| 1046 | * Set login name. |
| 1047 | */ |
| 1048 | /* ARGSUSED */ |
| 1049 | int |
| 1050 | setlogin(struct setlogin_args *uap) |
| 1051 | { |
| 1052 | struct proc *p = curproc; |
| 1053 | int error; |
| 1054 | char logintmp[MAXLOGNAME]; |
| 1055 | |
| 1056 | KKASSERT(p != NULL); |
| 1057 | if ((error = suser_cred(p->p_ucred, PRISON_ROOT))) |
| 1058 | return (error); |
| 1059 | error = copyinstr((caddr_t) uap->namebuf, (caddr_t) logintmp, |
| 1060 | sizeof(logintmp), (size_t *)0); |
| 1061 | if (error == ENAMETOOLONG) |
| 1062 | error = EINVAL; |
| 1063 | else if (!error) |
| 1064 | (void) memcpy(p->p_pgrp->pg_session->s_login, logintmp, |
| 1065 | sizeof(logintmp)); |
| 1066 | return (error); |
| 1067 | } |
| 1068 | |
| 1069 | void |
| 1070 | setsugid() |
| 1071 | { |
| 1072 | struct proc *p = curproc; |
| 1073 | |
| 1074 | KKASSERT(p != NULL); |
| 1075 | p->p_flag |= P_SUGID; |
| 1076 | if (!(p->p_pfsflags & PF_ISUGID)) |
| 1077 | p->p_stops = 0; |
| 1078 | } |
| 1079 | |
| 1080 | /* |
| 1081 | * Helper function to change the effective uid of a process |
| 1082 | */ |
| 1083 | void |
| 1084 | change_euid(uid_t euid) |
| 1085 | { |
| 1086 | struct proc *p = curproc; |
| 1087 | struct ucred *cr; |
| 1088 | |
| 1089 | KKASSERT(p != NULL); |
| 1090 | cr = cratom(&p->p_ucred); |
| 1091 | cr->cr_uid = euid; |
| 1092 | uireplace(&cr->cr_uidinfo, uifind(euid)); |
| 1093 | } |
| 1094 | |
| 1095 | /* |
| 1096 | * Helper function to change the real uid of a process |
| 1097 | * |
| 1098 | * The per-uid process count for this process is transfered from |
| 1099 | * the old uid to the new uid. |
| 1100 | */ |
| 1101 | void |
| 1102 | change_ruid(uid_t ruid) |
| 1103 | { |
| 1104 | struct proc *p = curproc; |
| 1105 | struct ucred *cr; |
| 1106 | |
| 1107 | KKASSERT(p != NULL); |
| 1108 | |
| 1109 | cr = cratom(&p->p_ucred); |
| 1110 | (void)chgproccnt(cr->cr_ruidinfo, -1, 0); |
| 1111 | /* It is assumed that pcred is not shared between processes */ |
| 1112 | cr->cr_ruid = ruid; |
| 1113 | uireplace(&cr->cr_ruidinfo, uifind(ruid)); |
| 1114 | (void)chgproccnt(cr->cr_ruidinfo, 1, 0); |
| 1115 | } |