1/*- 2 * Copyright (c) 1996 by 3 * Sean Eric Fagan <sef@kithrup.com> 4 * David Nugent <davidn@blaze.net.au> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, is permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice immediately at the beginning of the file, without modification, 12 * this list of conditions, and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. This work was done expressly for inclusion into FreeBSD. Other use 17 * is permitted provided this notation is included. 18 * 4. Absolutely no warranty of function or purpose is made by the authors. 19 * 5. Modifications may be freely made to this file providing the above 20 * conditions are met. 21 * 22 * High-level routines relating to use of the user capabilities database 23 */ 24 25#include <sys/param.h> 26#include <sys/cpuset.h> 27#include <sys/mac.h> 28#include <sys/resource.h> 29#include <sys/rtprio.h> 30#include <sys/stat.h> 31#include <sys/time.h> 32 33#include <ctype.h> 34#include <err.h> 35#include <errno.h> 36#include <fcntl.h> 37#include <login_cap.h> 38#include <paths.h> 39#include <pwd.h> 40#include <stdint.h> 41#include <stdio.h> 42#include <stdlib.h> 43#include <string.h> 44#include <syslog.h> 45#include <unistd.h> 46 47 48static struct login_res { 49 const char *what; 50 rlim_t (*who)(login_cap_t *, const char *, rlim_t, rlim_t); 51 int why; 52} resources[] = { 53 { "cputime", login_getcaptime, RLIMIT_CPU }, 54 { "filesize", login_getcapsize, RLIMIT_FSIZE }, 55 { "datasize", login_getcapsize, RLIMIT_DATA }, 56 { "stacksize", login_getcapsize, RLIMIT_STACK }, 57 { "memoryuse", login_getcapsize, RLIMIT_RSS }, 58 { "memorylocked", login_getcapsize, RLIMIT_MEMLOCK }, 59 { "maxproc", login_getcapnum, RLIMIT_NPROC }, 60 { "openfiles", login_getcapnum, RLIMIT_NOFILE }, 61 { "coredumpsize", login_getcapsize, RLIMIT_CORE }, 62 { "sbsize", login_getcapsize, RLIMIT_SBSIZE }, 63 { "vmemoryuse", login_getcapsize, RLIMIT_VMEM }, 64 { "pseudoterminals", login_getcapnum, RLIMIT_NPTS }, 65 { "swapuse", login_getcapsize, RLIMIT_SWAP }, 66 { "kqueues", login_getcapsize, RLIMIT_KQUEUES }, 67 { "umtxp", login_getcapnum, RLIMIT_UMTXP }, 68 { NULL, 0, 0 } 69}; 70 71 72void 73setclassresources(login_cap_t *lc) 74{ 75 struct login_res *lr; 76 77 if (lc == NULL) 78 return; 79 80 for (lr = resources; lr->what != NULL; ++lr) { 81 struct rlimit rlim; 82 83 /* 84 * The login.conf file can have <limit>, <limit>-max, and 85 * <limit>-cur entries. 86 * What we do is get the current current- and maximum- limits. 87 * Then, we try to get an entry for <limit> from the capability, 88 * using the current and max limits we just got as the 89 * default/error values. 90 * *Then*, we try looking for <limit>-cur and <limit>-max, 91 * again using the appropriate values as the default/error 92 * conditions. 93 */ 94 95 if (getrlimit(lr->why, &rlim) != 0) 96 syslog(LOG_ERR, "getting %s resource limit: %m", lr->what); 97 else { 98 char name_cur[40]; 99 char name_max[40]; 100 rlim_t rcur = rlim.rlim_cur; 101 rlim_t rmax = rlim.rlim_max; 102 103 sprintf(name_cur, "%s-cur", lr->what); 104 sprintf(name_max, "%s-max", lr->what); 105 106 rcur = (*lr->who)(lc, lr->what, rcur, rcur); 107 rmax = (*lr->who)(lc, lr->what, rmax, rmax); 108 rlim.rlim_cur = (*lr->who)(lc, name_cur, rcur, rcur); 109 rlim.rlim_max = (*lr->who)(lc, name_max, rmax, rmax); 110 111 if (setrlimit(lr->why, &rlim) == -1) 112 syslog(LOG_WARNING, "set class '%s' resource limit %s: %m", lc->lc_class, lr->what); 113 } 114 } 115} 116 117 118 119static struct login_vars { 120 const char *tag; 121 const char *var; 122 const char *def; 123 int overwrite; 124} pathvars[] = { 125 { "path", "PATH", NULL, 1}, 126 { "cdpath", "CDPATH", NULL, 1}, 127 { "manpath", "MANPATH", NULL, 1}, 128 { NULL, NULL, NULL, 0} 129}, envars[] = { 130 { "lang", "LANG", NULL, 1}, 131 { "charset", "MM_CHARSET", NULL, 1}, 132 { "mail", "MAIL", NULL, 1}, 133 { "timezone", "TZ", NULL, 1}, 134 { "term", "TERM", NULL, 0}, 135 { NULL, NULL, NULL, 0} 136}; 137 138static char * 139substvar(const char * var, const struct passwd * pwd, int hlen, int pch, int nlen) 140{ 141 char *np = NULL; 142 143 if (var != NULL) { 144 int tildes = 0; 145 int dollas = 0; 146 char *p; 147 const char *q; 148 149 if (pwd != NULL) { 150 for (q = var; *q != '\0'; ++q) { 151 tildes += (*q == '~'); 152 dollas += (*q == '$'); 153 } 154 } 155 156 np = malloc(strlen(var) + (dollas * nlen) 157 - dollas + (tildes * (pch+hlen)) 158 - tildes + 1); 159 160 if (np != NULL) { 161 p = strcpy(np, var); 162 163 if (pwd != NULL) { 164 /* 165 * This loop does user username and homedir substitutions 166 * for unescaped $ (username) and ~ (homedir) 167 */ 168 while (*(p += strcspn(p, "~$")) != '\0') { 169 int l = strlen(p); 170 171 if (p > np && *(p-1) == '\\') /* Escaped: */ 172 memmove(p - 1, p, l + 1); /* Slide-out the backslash */ 173 else if (*p == '~') { 174 int v = pch && *(p+1) != '/'; /* Avoid double // */ 175 memmove(p + hlen + v, p + 1, l); /* Subst homedir */ 176 memmove(p, pwd->pw_dir, hlen); 177 if (v) 178 p[hlen] = '/'; 179 p += hlen + v; 180 } 181 else /* if (*p == '$') */ { 182 memmove(p + nlen, p + 1, l); /* Subst username */ 183 memmove(p, pwd->pw_name, nlen); 184 p += nlen; 185 } 186 } 187 } 188 } 189 } 190 191 return (np); 192} 193 194 195void 196setclassenvironment(login_cap_t *lc, const struct passwd * pwd, int paths) 197{ 198 struct login_vars *vars = paths ? pathvars : envars; 199 int hlen = pwd ? strlen(pwd->pw_dir) : 0; 200 int nlen = pwd ? strlen(pwd->pw_name) : 0; 201 char pch = 0; 202 203 if (hlen && pwd->pw_dir[hlen-1] != '/') 204 ++pch; 205 206 while (vars->tag != NULL) { 207 const char * var = paths ? login_getpath(lc, vars->tag, NULL) 208 : login_getcapstr(lc, vars->tag, NULL, NULL); 209 210 char * np = substvar(var, pwd, hlen, pch, nlen); 211 212 if (np != NULL) { 213 setenv(vars->var, np, vars->overwrite); 214 free(np); 215 } else if (vars->def != NULL) { 216 setenv(vars->var, vars->def, 0); 217 } 218 ++vars; 219 } 220 221 /* 222 * If we're not processing paths, then see if there is a setenv list by 223 * which the admin and/or user may set an arbitrary set of env vars. 224 */ 225 if (!paths) { 226 const char **set_env = login_getcaplist(lc, "setenv", ","); 227 228 if (set_env != NULL) { 229 while (*set_env != NULL) { 230 char *p = strchr(*set_env, '='); 231 232 if (p != NULL && p != *set_env) { /* Discard invalid entries */ 233 const char *ep; 234 char *np; 235 236 *p++ = '\0'; 237 /* Strip leading spaces from variable name */ 238 ep = *set_env; 239 while (*ep == ' ' || *ep == '\t') 240 ep++; 241 if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) { 242 setenv(ep, np, 1); 243 free(np); 244 } 245 } 246 ++set_env; 247 } 248 } 249 } 250} 251 252 253static int 254list2cpuset(const char *list, cpuset_t *mask) 255{ 256 enum { NONE, NUM, DASH } state; 257 int lastnum; 258 int curnum; 259 const char *l; 260 261 state = NONE; 262 curnum = lastnum = 0; 263 for (l = list; *l != '\0';) { 264 if (isdigit(*l)) { 265 curnum = atoi(l); 266 if (curnum > CPU_SETSIZE) 267 errx(EXIT_FAILURE, 268 "Only %d cpus supported", CPU_SETSIZE); 269 while (isdigit(*l)) 270 l++; 271 switch (state) { 272 case NONE: 273 lastnum = curnum; 274 state = NUM; 275 break; 276 case DASH: 277 for (; lastnum <= curnum; lastnum++) 278 CPU_SET(lastnum, mask); 279 state = NONE; 280 break; 281 case NUM: 282 default: 283 return (0); 284 } 285 continue; 286 } 287 switch (*l) { 288 case ',': 289 switch (state) { 290 case NONE: 291 break; 292 case NUM: 293 CPU_SET(curnum, mask); 294 state = NONE; 295 break; 296 case DASH: 297 return (0); 298 break; 299 } 300 break; 301 case '-': 302 if (state != NUM) 303 return (0); 304 state = DASH; 305 break; 306 default: 307 return (0); 308 } 309 l++; 310 } 311 switch (state) { 312 case NONE: 313 break; 314 case NUM: 315 CPU_SET(curnum, mask); 316 break; 317 case DASH: 318 return (0); 319 } 320 return (1); 321} 322 323 324void 325setclasscpumask(login_cap_t *lc) 326{ 327 const char *maskstr; 328 cpuset_t maskset; 329 cpusetid_t setid; 330 331 maskstr = login_getcapstr(lc, "cpumask", NULL, NULL); 332 CPU_ZERO(&maskset); 333 if (maskstr == NULL) 334 return; 335 if (strcasecmp("default", maskstr) == 0) 336 return; 337 if (!list2cpuset(maskstr, &maskset)) { 338 syslog(LOG_WARNING, 339 "list2cpuset(%s) invalid mask specification", maskstr); 340 return; 341 } 342 343 if (cpuset(&setid) != 0) { 344 syslog(LOG_ERR, "cpuset(): %s", strerror(errno)); 345 return; 346 } 347 348 if (cpuset_setaffinity(CPU_LEVEL_CPUSET, CPU_WHICH_PID, -1, 349 sizeof(maskset), &maskset) != 0) 350 syslog(LOG_ERR, "cpuset_setaffinity(%s): %s", maskstr, 351 strerror(errno)); 352} 353 354 355/* 356 * setclasscontext() 357 * 358 * For the login class <class>, set various class context values 359 * (limits, mainly) to the values for that class. Which values are 360 * set are controlled by <flags> -- see <login_class.h> for the 361 * possible values. 362 * 363 * setclasscontext() can only set resources, priority, and umask. 364 */ 365 366int 367setclasscontext(const char *classname, unsigned int flags) 368{ 369 int rc; 370 login_cap_t *lc; 371 372 lc = login_getclassbyname(classname, NULL); 373 374 flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY | 375 LOGIN_SETUMASK | LOGIN_SETPATH; 376 377 rc = lc ? setusercontext(lc, NULL, 0, flags) : -1; 378 login_close(lc); 379 return (rc); 380} 381 382 383static const char * const inherit_enum[] = { 384 "inherit", 385 NULL 386}; 387 388/* 389 * Private function setting umask from the login class. 390 */ 391static void 392setclassumask(login_cap_t *lc, const struct passwd *pwd) 393{ 394 /* 395 * Make it unlikely that someone would input our default sentinel 396 * indicating no specification. 397 */ 398 const rlim_t def_val = INT64_MIN + 1, err_val = INT64_MIN; 399 rlim_t val; 400 401 /* If value is "inherit", nothing to change. */ 402 if (login_getcapenum(lc, "umask", inherit_enum) == 0) 403 return; 404 405 val = login_getcapnum(lc, "umask", def_val, err_val); 406 407 if (val != def_val) { 408 if (val < 0 || val > UINT16_MAX) { 409 /* We get here also on 'err_val'. */ 410 syslog(LOG_WARNING, 411 "%s%s%sLogin class '%s': " 412 "Invalid umask specification: '%s'", 413 pwd ? "Login '" : "", 414 pwd ? pwd->pw_name : "", 415 pwd ? "': " : "", 416 lc->lc_class, 417 login_getcapstr(lc, "umask", "", "")); 418 } else { 419 const mode_t mode = val; 420 421 umask(mode); 422 } 423 } 424} 425 426/* 427 * Private function which takes care of processing 428 */ 429 430static void 431setlogincontext(login_cap_t *lc, const struct passwd *pwd, unsigned long flags) 432{ 433 if (lc == NULL) 434 return; 435 436 /* Set resources. */ 437 if ((flags & LOGIN_SETRESOURCES) != 0) 438 setclassresources(lc); 439 440 /* See if there's a umask override. */ 441 if ((flags & LOGIN_SETUMASK) != 0) 442 setclassumask(lc, pwd); 443 444 /* Set paths. */ 445 if ((flags & LOGIN_SETPATH) != 0) 446 setclassenvironment(lc, pwd, 1); 447 448 /* Set environment. */ 449 if ((flags & LOGIN_SETENV) != 0) 450 setclassenvironment(lc, pwd, 0); 451 452 /* Set cpu affinity. */ 453 if ((flags & LOGIN_SETCPUMASK) != 0) 454 setclasscpumask(lc); 455} 456 457 458/* 459 * Private function to set process priority. 460 */ 461static void 462setclasspriority(login_cap_t * const lc, struct passwd const * const pwd) 463{ 464 const rlim_t def_val = 0, err_val = INT64_MIN; 465 rlim_t p; 466 int rc; 467 468 /* If value is "inherit", nothing to change. */ 469 if (login_getcapenum(lc, "priority", inherit_enum) == 0) 470 return; 471 472 p = login_getcapnum(lc, "priority", def_val, err_val); 473 474 if (p == err_val) { 475 /* Invariant: 'lc' != NULL. */ 476 syslog(LOG_WARNING, 477 "%s%s%sLogin class '%s': " 478 "Invalid priority specification: '%s'", 479 pwd ? "Login '" : "", 480 pwd ? pwd->pw_name : "", 481 pwd ? "': " : "", 482 lc->lc_class, 483 login_getcapstr(lc, "priority", "", "")); 484 /* Reset the priority, as if the capability was not present. */ 485 p = def_val; 486 } 487 488 if (p > PRIO_MAX) { 489 struct rtprio rtp; 490 491 rtp.type = RTP_PRIO_IDLE; 492 p += RTP_PRIO_MIN - (PRIO_MAX + 1); 493 rtp.prio = p > RTP_PRIO_MAX ? RTP_PRIO_MAX : p; 494 rc = rtprio(RTP_SET, 0, &rtp); 495 } else if (p < PRIO_MIN) { 496 struct rtprio rtp; 497 498 rtp.type = RTP_PRIO_REALTIME; 499 p += RTP_PRIO_MAX - (PRIO_MIN - 1); 500 rtp.prio = p < RTP_PRIO_MIN ? RTP_PRIO_MIN : p; 501 rc = rtprio(RTP_SET, 0, &rtp); 502 } else 503 rc = setpriority(PRIO_PROCESS, 0, (int)p); 504 505 if (rc != 0) 506 syslog(LOG_WARNING, 507 "%s%s%sLogin class '%s': " 508 "Setting priority failed: %m", 509 pwd ? "Login '" : "", 510 pwd ? pwd->pw_name : "", 511 pwd ? "': " : "", 512 lc ? lc->lc_class : "<none>"); 513} 514 515/* 516 * setusercontext() 517 * 518 * Given a login class <lc> and a user in <pwd>, with a uid <uid>, 519 * set the context as in setclasscontext(). <flags> controls which 520 * values are set. 521 * 522 * The difference between setclasscontext() and setusercontext() is 523 * that the former sets things up for an already-existing process, 524 * while the latter sets things up from a root context. Such as might 525 * be called from login(1). 526 * 527 */ 528 529int 530setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags) 531{ 532 login_cap_t *llc = NULL; 533 int error; 534 535 if (lc == NULL) { 536 if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL) 537 llc = lc; /* free this when we're done */ 538 } 539 540 if (flags & LOGIN_SETPATH) 541 pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH; 542 543 /* we need a passwd entry to set these */ 544 if (pwd == NULL) 545 flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN | LOGIN_SETMAC); 546 547 /* Set the process priority */ 548 if (flags & LOGIN_SETPRIORITY) 549 setclasspriority(lc, pwd); 550 551 /* Setup the user's group permissions */ 552 if (flags & LOGIN_SETGROUP) { 553 if (setgid(pwd->pw_gid) != 0) { 554 syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid); 555 login_close(llc); 556 return (-1); 557 } 558 if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) { 559 syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name, 560 (u_long)pwd->pw_gid); 561 login_close(llc); 562 return (-1); 563 } 564 } 565 566 /* Set up the user's MAC label. */ 567 if ((flags & LOGIN_SETMAC) && mac_is_present(NULL) == 1) { 568 const char *label_string; 569 mac_t label; 570 571 label_string = login_getcapstr(lc, "label", NULL, NULL); 572 if (label_string != NULL) { 573 if (mac_from_text(&label, label_string) == -1) { 574 syslog(LOG_ERR, "mac_from_text('%s') for %s: %m", 575 pwd->pw_name, label_string); 576 return (-1); 577 } 578 if (mac_set_proc(label) == -1) 579 error = errno; 580 else 581 error = 0; 582 mac_free(label); 583 if (error != 0) { 584 syslog(LOG_ERR, "mac_set_proc('%s') for %s: %s", 585 label_string, pwd->pw_name, strerror(error)); 586 return (-1); 587 } 588 } 589 } 590 591 /* Set the sessions login */ 592 if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) { 593 syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name); 594 login_close(llc); 595 return (-1); 596 } 597 598 /* Inform the kernel about current login class */ 599 if (lc != NULL && lc->lc_class != NULL && (flags & LOGIN_SETLOGINCLASS)) { 600 error = setloginclass(lc->lc_class); 601 if (error != 0) { 602 syslog(LOG_ERR, "setloginclass(%s): %m", lc->lc_class); 603#ifdef notyet 604 login_close(llc); 605 return (-1); 606#endif 607 } 608 } 609 610 setlogincontext(lc, pwd, flags); 611 login_close(llc); 612 613 /* This needs to be done after anything that needs root privs */ 614 if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) { 615 syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid); 616 return (-1); /* Paranoia again */ 617 } 618 619 /* 620 * Now, we repeat some of the above for the user's private entries 621 */ 622 if (geteuid() == uid && (lc = login_getuserclass(pwd)) != NULL) { 623 setlogincontext(lc, pwd, flags); 624 if (flags & LOGIN_SETPRIORITY) 625 setclasspriority(lc, pwd); 626 login_close(lc); 627 } 628 629 return (0); 630} 631