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 <stdio.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <syslog.h> 47 #include <unistd.h> 48 49 50 static struct login_res { 51 const char *what; 52 rlim_t (*who)(login_cap_t *, const char *, rlim_t, rlim_t); 53 int why; 54 } resources[] = { 55 { "cputime", login_getcaptime, RLIMIT_CPU }, 56 { "filesize", login_getcapsize, RLIMIT_FSIZE }, 57 { "datasize", login_getcapsize, RLIMIT_DATA }, 58 { "stacksize", login_getcapsize, RLIMIT_STACK }, 59 { "memoryuse", login_getcapsize, RLIMIT_RSS }, 60 { "memorylocked", login_getcapsize, RLIMIT_MEMLOCK }, 61 { "maxproc", login_getcapnum, RLIMIT_NPROC }, 62 { "openfiles", login_getcapnum, RLIMIT_NOFILE }, 63 { "coredumpsize", login_getcapsize, RLIMIT_CORE }, 64 { "sbsize", login_getcapsize, RLIMIT_SBSIZE }, 65 { "vmemoryuse", login_getcapsize, RLIMIT_VMEM }, 66 { "pseudoterminals", login_getcapnum, RLIMIT_NPTS }, 67 { "swapuse", login_getcapsize, RLIMIT_SWAP }, 68 { "kqueues", login_getcapsize, RLIMIT_KQUEUES }, 69 { "umtxp", login_getcapnum, RLIMIT_UMTXP }, 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 { "mail", "MAIL", 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 && p != *set_env) { /* Discard invalid entries */ 235 const char *ep; 236 char *np; 237 238 *p++ = '\0'; 239 /* Strip leading spaces from variable name */ 240 ep = *set_env; 241 while (*ep == ' ' || *ep == '\t') 242 ep++; 243 if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) { 244 setenv(ep, np, 1); 245 free(np); 246 } 247 } 248 ++set_env; 249 } 250 } 251 } 252 } 253 254 255 static int 256 list2cpuset(const char *list, cpuset_t *mask) 257 { 258 enum { NONE, NUM, DASH } state; 259 int lastnum; 260 int curnum; 261 const char *l; 262 263 state = NONE; 264 curnum = lastnum = 0; 265 for (l = list; *l != '\0';) { 266 if (isdigit(*l)) { 267 curnum = atoi(l); 268 if (curnum > CPU_SETSIZE) 269 errx(EXIT_FAILURE, 270 "Only %d cpus supported", CPU_SETSIZE); 271 while (isdigit(*l)) 272 l++; 273 switch (state) { 274 case NONE: 275 lastnum = curnum; 276 state = NUM; 277 break; 278 case DASH: 279 for (; lastnum <= curnum; lastnum++) 280 CPU_SET(lastnum, mask); 281 state = NONE; 282 break; 283 case NUM: 284 default: 285 return (0); 286 } 287 continue; 288 } 289 switch (*l) { 290 case ',': 291 switch (state) { 292 case NONE: 293 break; 294 case NUM: 295 CPU_SET(curnum, mask); 296 state = NONE; 297 break; 298 case DASH: 299 return (0); 300 break; 301 } 302 break; 303 case '-': 304 if (state != NUM) 305 return (0); 306 state = DASH; 307 break; 308 default: 309 return (0); 310 } 311 l++; 312 } 313 switch (state) { 314 case NONE: 315 break; 316 case NUM: 317 CPU_SET(curnum, mask); 318 break; 319 case DASH: 320 return (0); 321 } 322 return (1); 323 } 324 325 326 void 327 setclasscpumask(login_cap_t *lc) 328 { 329 const char *maskstr; 330 cpuset_t maskset; 331 cpusetid_t setid; 332 333 maskstr = login_getcapstr(lc, "cpumask", NULL, NULL); 334 CPU_ZERO(&maskset); 335 if (maskstr == NULL) 336 return; 337 if (strcasecmp("default", maskstr) == 0) 338 return; 339 if (!list2cpuset(maskstr, &maskset)) { 340 syslog(LOG_WARNING, 341 "list2cpuset(%s) invalid mask specification", maskstr); 342 return; 343 } 344 345 if (cpuset(&setid) != 0) { 346 syslog(LOG_ERR, "cpuset(): %s", strerror(errno)); 347 return; 348 } 349 350 if (cpuset_setaffinity(CPU_LEVEL_CPUSET, CPU_WHICH_PID, -1, 351 sizeof(maskset), &maskset) != 0) 352 syslog(LOG_ERR, "cpuset_setaffinity(%s): %s", maskstr, 353 strerror(errno)); 354 } 355 356 357 /* 358 * setclasscontext() 359 * 360 * For the login class <class>, set various class context values 361 * (limits, mainly) to the values for that class. Which values are 362 * set are controlled by <flags> -- see <login_class.h> for the 363 * possible values. 364 * 365 * setclasscontext() can only set resources, priority, and umask. 366 */ 367 368 int 369 setclasscontext(const char *classname, unsigned int flags) 370 { 371 int rc; 372 login_cap_t *lc; 373 374 lc = login_getclassbyname(classname, NULL); 375 376 flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY | 377 LOGIN_SETUMASK | LOGIN_SETPATH; 378 379 rc = lc ? setusercontext(lc, NULL, 0, flags) : -1; 380 login_close(lc); 381 return (rc); 382 } 383 384 385 386 /* 387 * Private function which takes care of processing 388 */ 389 390 static mode_t 391 setlogincontext(login_cap_t *lc, const struct passwd *pwd, 392 mode_t mymask, unsigned long flags) 393 { 394 if (lc) { 395 /* Set resources */ 396 if (flags & LOGIN_SETRESOURCES) 397 setclassresources(lc); 398 /* See if there's a umask override */ 399 if (flags & LOGIN_SETUMASK) 400 mymask = (mode_t)login_getcapnum(lc, "umask", mymask, mymask); 401 /* Set paths */ 402 if (flags & LOGIN_SETPATH) 403 setclassenvironment(lc, pwd, 1); 404 /* Set environment */ 405 if (flags & LOGIN_SETENV) 406 setclassenvironment(lc, pwd, 0); 407 /* Set cpu affinity */ 408 if (flags & LOGIN_SETCPUMASK) 409 setclasscpumask(lc); 410 } 411 return (mymask); 412 } 413 414 415 416 /* 417 * setusercontext() 418 * 419 * Given a login class <lc> and a user in <pwd>, with a uid <uid>, 420 * set the context as in setclasscontext(). <flags> controls which 421 * values are set. 422 * 423 * The difference between setclasscontext() and setusercontext() is 424 * that the former sets things up for an already-existing process, 425 * while the latter sets things up from a root context. Such as might 426 * be called from login(1). 427 * 428 */ 429 430 int 431 setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags) 432 { 433 rlim_t p; 434 mode_t mymask; 435 login_cap_t *llc = NULL; 436 struct rtprio rtp; 437 int error; 438 439 if (lc == NULL) { 440 if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL) 441 llc = lc; /* free this when we're done */ 442 } 443 444 if (flags & LOGIN_SETPATH) 445 pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH; 446 447 /* we need a passwd entry to set these */ 448 if (pwd == NULL) 449 flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN | LOGIN_SETMAC); 450 451 /* Set the process priority */ 452 if (flags & LOGIN_SETPRIORITY) { 453 p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI); 454 455 if (p > PRIO_MAX) { 456 rtp.type = RTP_PRIO_IDLE; 457 p -= PRIO_MAX + 1; 458 rtp.prio = p > RTP_PRIO_MAX ? RTP_PRIO_MAX : p; 459 if (rtprio(RTP_SET, 0, &rtp)) 460 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 461 pwd ? pwd->pw_name : "-", 462 lc ? lc->lc_class : LOGIN_DEFCLASS); 463 } else if (p < PRIO_MIN) { 464 rtp.type = RTP_PRIO_REALTIME; 465 p -= PRIO_MIN - RTP_PRIO_MAX; 466 rtp.prio = p < RTP_PRIO_MIN ? RTP_PRIO_MIN : p; 467 if (rtprio(RTP_SET, 0, &rtp)) 468 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 469 pwd ? pwd->pw_name : "-", 470 lc ? lc->lc_class : LOGIN_DEFCLASS); 471 } else { 472 if (setpriority(PRIO_PROCESS, 0, (int)p) != 0) 473 syslog(LOG_WARNING, "setpriority '%s' (%s): %m", 474 pwd ? pwd->pw_name : "-", 475 lc ? lc->lc_class : LOGIN_DEFCLASS); 476 } 477 } 478 479 /* Setup the user's group permissions */ 480 if (flags & LOGIN_SETGROUP) { 481 if (setgid(pwd->pw_gid) != 0) { 482 syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid); 483 login_close(llc); 484 return (-1); 485 } 486 if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) { 487 syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name, 488 (u_long)pwd->pw_gid); 489 login_close(llc); 490 return (-1); 491 } 492 } 493 494 /* Set up the user's MAC label. */ 495 if ((flags & LOGIN_SETMAC) && mac_is_present(NULL) == 1) { 496 const char *label_string; 497 mac_t label; 498 499 label_string = login_getcapstr(lc, "label", NULL, NULL); 500 if (label_string != NULL) { 501 if (mac_from_text(&label, label_string) == -1) { 502 syslog(LOG_ERR, "mac_from_text('%s') for %s: %m", 503 pwd->pw_name, label_string); 504 return (-1); 505 } 506 if (mac_set_proc(label) == -1) 507 error = errno; 508 else 509 error = 0; 510 mac_free(label); 511 if (error != 0) { 512 syslog(LOG_ERR, "mac_set_proc('%s') for %s: %s", 513 label_string, pwd->pw_name, strerror(error)); 514 return (-1); 515 } 516 } 517 } 518 519 /* Set the sessions login */ 520 if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) { 521 syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name); 522 login_close(llc); 523 return (-1); 524 } 525 526 /* Inform the kernel about current login class */ 527 if (lc != NULL && lc->lc_class != NULL && (flags & LOGIN_SETLOGINCLASS)) { 528 error = setloginclass(lc->lc_class); 529 if (error != 0) { 530 syslog(LOG_ERR, "setloginclass(%s): %m", lc->lc_class); 531 #ifdef notyet 532 login_close(llc); 533 return (-1); 534 #endif 535 } 536 } 537 538 mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0; 539 mymask = setlogincontext(lc, pwd, mymask, flags); 540 login_close(llc); 541 542 /* This needs to be done after anything that needs root privs */ 543 if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) { 544 syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid); 545 return (-1); /* Paranoia again */ 546 } 547 548 /* 549 * Now, we repeat some of the above for the user's private entries 550 */ 551 if (getuid() == uid && (lc = login_getuserclass(pwd)) != NULL) { 552 mymask = setlogincontext(lc, pwd, mymask, flags); 553 login_close(lc); 554 } 555 556 /* Finally, set any umask we've found */ 557 if (flags & LOGIN_SETUMASK) 558 umask(mymask); 559 560 return (0); 561 } 562