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