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