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 { NULL, 0, 0 } 69 }; 70 71 72 void 73 setclassresources(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 } 116 117 118 119 static 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 { "timezone", "TZ", NULL, 1}, 133 { "term", "TERM", NULL, 0}, 134 { NULL, NULL, NULL, 0} 135 }; 136 137 static char * 138 substvar(const char * var, const struct passwd * pwd, int hlen, int pch, int nlen) 139 { 140 char *np = NULL; 141 142 if (var != NULL) { 143 int tildes = 0; 144 int dollas = 0; 145 char *p; 146 const char *q; 147 148 if (pwd != NULL) { 149 for (q = var; *q != '\0'; ++q) { 150 tildes += (*q == '~'); 151 dollas += (*q == '$'); 152 } 153 } 154 155 np = malloc(strlen(var) + (dollas * nlen) 156 - dollas + (tildes * (pch+hlen)) 157 - tildes + 1); 158 159 if (np != NULL) { 160 p = strcpy(np, var); 161 162 if (pwd != NULL) { 163 /* 164 * This loop does user username and homedir substitutions 165 * for unescaped $ (username) and ~ (homedir) 166 */ 167 while (*(p += strcspn(p, "~$")) != '\0') { 168 int l = strlen(p); 169 170 if (p > np && *(p-1) == '\\') /* Escaped: */ 171 memmove(p - 1, p, l + 1); /* Slide-out the backslash */ 172 else if (*p == '~') { 173 int v = pch && *(p+1) != '/'; /* Avoid double // */ 174 memmove(p + hlen + v, p + 1, l); /* Subst homedir */ 175 memmove(p, pwd->pw_dir, hlen); 176 if (v) 177 p[hlen] = '/'; 178 p += hlen + v; 179 } 180 else /* if (*p == '$') */ { 181 memmove(p + nlen, p + 1, l); /* Subst username */ 182 memmove(p, pwd->pw_name, nlen); 183 p += nlen; 184 } 185 } 186 } 187 } 188 } 189 190 return (np); 191 } 192 193 194 void 195 setclassenvironment(login_cap_t *lc, const struct passwd * pwd, int paths) 196 { 197 struct login_vars *vars = paths ? pathvars : envars; 198 int hlen = pwd ? strlen(pwd->pw_dir) : 0; 199 int nlen = pwd ? strlen(pwd->pw_name) : 0; 200 char pch = 0; 201 202 if (hlen && pwd->pw_dir[hlen-1] != '/') 203 ++pch; 204 205 while (vars->tag != NULL) { 206 const char * var = paths ? login_getpath(lc, vars->tag, NULL) 207 : login_getcapstr(lc, vars->tag, NULL, NULL); 208 209 char * np = substvar(var, pwd, hlen, pch, nlen); 210 211 if (np != NULL) { 212 setenv(vars->var, np, vars->overwrite); 213 free(np); 214 } else if (vars->def != NULL) { 215 setenv(vars->var, vars->def, 0); 216 } 217 ++vars; 218 } 219 220 /* 221 * If we're not processing paths, then see if there is a setenv list by 222 * which the admin and/or user may set an arbitrary set of env vars. 223 */ 224 if (!paths) { 225 const char **set_env = login_getcaplist(lc, "setenv", ","); 226 227 if (set_env != NULL) { 228 while (*set_env != NULL) { 229 char *p = strchr(*set_env, '='); 230 231 if (p != NULL) { /* Discard invalid entries */ 232 char *np; 233 234 *p++ = '\0'; 235 if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) { 236 setenv(*set_env, np, 1); 237 free(np); 238 } 239 } 240 ++set_env; 241 } 242 } 243 } 244 } 245 246 247 static int 248 list2cpuset(const char *list, cpuset_t *mask) 249 { 250 enum { NONE, NUM, DASH } state; 251 int lastnum; 252 int curnum; 253 const char *l; 254 255 state = NONE; 256 curnum = lastnum = 0; 257 for (l = list; *l != '\0';) { 258 if (isdigit(*l)) { 259 curnum = atoi(l); 260 if (curnum > CPU_SETSIZE) 261 errx(EXIT_FAILURE, 262 "Only %d cpus supported", CPU_SETSIZE); 263 while (isdigit(*l)) 264 l++; 265 switch (state) { 266 case NONE: 267 lastnum = curnum; 268 state = NUM; 269 break; 270 case DASH: 271 for (; lastnum <= curnum; lastnum++) 272 CPU_SET(lastnum, mask); 273 state = NONE; 274 break; 275 case NUM: 276 default: 277 return (0); 278 } 279 continue; 280 } 281 switch (*l) { 282 case ',': 283 switch (state) { 284 case NONE: 285 break; 286 case NUM: 287 CPU_SET(curnum, mask); 288 state = NONE; 289 break; 290 case DASH: 291 return (0); 292 break; 293 } 294 break; 295 case '-': 296 if (state != NUM) 297 return (0); 298 state = DASH; 299 break; 300 default: 301 return (0); 302 } 303 l++; 304 } 305 switch (state) { 306 case NONE: 307 break; 308 case NUM: 309 CPU_SET(curnum, mask); 310 break; 311 case DASH: 312 return (0); 313 } 314 return (1); 315 } 316 317 318 void 319 setclasscpumask(login_cap_t *lc) 320 { 321 const char *maskstr; 322 cpuset_t maskset; 323 cpusetid_t setid; 324 325 maskstr = login_getcapstr(lc, "cpumask", NULL, NULL); 326 CPU_ZERO(&maskset); 327 if (maskstr == NULL) 328 return; 329 if (strcasecmp("default", maskstr) == 0) 330 return; 331 if (!list2cpuset(maskstr, &maskset)) { 332 syslog(LOG_WARNING, 333 "list2cpuset(%s) invalid mask specification", maskstr); 334 return; 335 } 336 337 if (cpuset(&setid) != 0) { 338 syslog(LOG_ERR, "cpuset(): %s", strerror(errno)); 339 return; 340 } 341 342 if (cpuset_setaffinity(CPU_LEVEL_CPUSET, CPU_WHICH_PID, -1, 343 sizeof(maskset), &maskset) != 0) 344 syslog(LOG_ERR, "cpuset_setaffinity(%s): %s", maskstr, 345 strerror(errno)); 346 } 347 348 349 /* 350 * setclasscontext() 351 * 352 * For the login class <class>, set various class context values 353 * (limits, mainly) to the values for that class. Which values are 354 * set are controlled by <flags> -- see <login_class.h> for the 355 * possible values. 356 * 357 * setclasscontext() can only set resources, priority, and umask. 358 */ 359 360 int 361 setclasscontext(const char *classname, unsigned int flags) 362 { 363 int rc; 364 login_cap_t *lc; 365 366 lc = login_getclassbyname(classname, NULL); 367 368 flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY | 369 LOGIN_SETUMASK | LOGIN_SETPATH; 370 371 rc = lc ? setusercontext(lc, NULL, 0, flags) : -1; 372 login_close(lc); 373 return (rc); 374 } 375 376 377 378 /* 379 * Private function which takes care of processing 380 */ 381 382 static mode_t 383 setlogincontext(login_cap_t *lc, const struct passwd *pwd, 384 mode_t mymask, unsigned long flags) 385 { 386 if (lc) { 387 /* Set resources */ 388 if (flags & LOGIN_SETRESOURCES) 389 setclassresources(lc); 390 /* See if there's a umask override */ 391 if (flags & LOGIN_SETUMASK) 392 mymask = (mode_t)login_getcapnum(lc, "umask", mymask, mymask); 393 /* Set paths */ 394 if (flags & LOGIN_SETPATH) 395 setclassenvironment(lc, pwd, 1); 396 /* Set environment */ 397 if (flags & LOGIN_SETENV) 398 setclassenvironment(lc, pwd, 0); 399 /* Set cpu affinity */ 400 if (flags & LOGIN_SETCPUMASK) 401 setclasscpumask(lc); 402 } 403 return (mymask); 404 } 405 406 407 408 /* 409 * setusercontext() 410 * 411 * Given a login class <lc> and a user in <pwd>, with a uid <uid>, 412 * set the context as in setclasscontext(). <flags> controls which 413 * values are set. 414 * 415 * The difference between setclasscontext() and setusercontext() is 416 * that the former sets things up for an already-existing process, 417 * while the latter sets things up from a root context. Such as might 418 * be called from login(1). 419 * 420 */ 421 422 int 423 setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags) 424 { 425 quad_t p; 426 mode_t mymask; 427 login_cap_t *llc = NULL; 428 struct rtprio rtp; 429 int error; 430 431 if (lc == NULL) { 432 if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL) 433 llc = lc; /* free this when we're done */ 434 } 435 436 if (flags & LOGIN_SETPATH) 437 pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH; 438 439 /* we need a passwd entry to set these */ 440 if (pwd == NULL) 441 flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN | LOGIN_SETMAC); 442 443 /* Set the process priority */ 444 if (flags & LOGIN_SETPRIORITY) { 445 p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI); 446 447 if (p > PRIO_MAX) { 448 rtp.type = RTP_PRIO_IDLE; 449 rtp.prio = p - PRIO_MAX - 1; 450 p = (rtp.prio > RTP_PRIO_MAX) ? 31 : p; 451 if (rtprio(RTP_SET, 0, &rtp)) 452 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 453 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 454 } else if (p < PRIO_MIN) { 455 rtp.type = RTP_PRIO_REALTIME; 456 rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX); 457 p = (rtp.prio > RTP_PRIO_MAX) ? 1 : p; 458 if (rtprio(RTP_SET, 0, &rtp)) 459 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 460 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 461 } else { 462 if (setpriority(PRIO_PROCESS, 0, (int)p) != 0) 463 syslog(LOG_WARNING, "setpriority '%s' (%s): %m", 464 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 465 } 466 } 467 468 /* Setup the user's group permissions */ 469 if (flags & LOGIN_SETGROUP) { 470 if (setgid(pwd->pw_gid) != 0) { 471 syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid); 472 login_close(llc); 473 return (-1); 474 } 475 if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) { 476 syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name, 477 (u_long)pwd->pw_gid); 478 login_close(llc); 479 return (-1); 480 } 481 } 482 483 /* Set up the user's MAC label. */ 484 if ((flags & LOGIN_SETMAC) && mac_is_present(NULL) == 1) { 485 const char *label_string; 486 mac_t label; 487 488 label_string = login_getcapstr(lc, "label", NULL, NULL); 489 if (label_string != NULL) { 490 if (mac_from_text(&label, label_string) == -1) { 491 syslog(LOG_ERR, "mac_from_text('%s') for %s: %m", 492 pwd->pw_name, label_string); 493 return (-1); 494 } 495 if (mac_set_proc(label) == -1) 496 error = errno; 497 else 498 error = 0; 499 mac_free(label); 500 if (error != 0) { 501 syslog(LOG_ERR, "mac_set_proc('%s') for %s: %s", 502 label_string, pwd->pw_name, strerror(error)); 503 return (-1); 504 } 505 } 506 } 507 508 /* Set the sessions login */ 509 if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) { 510 syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name); 511 login_close(llc); 512 return (-1); 513 } 514 515 mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0; 516 mymask = setlogincontext(lc, pwd, mymask, flags); 517 login_close(llc); 518 519 /* This needs to be done after anything that needs root privs */ 520 if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) { 521 syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid); 522 return (-1); /* Paranoia again */ 523 } 524 525 /* 526 * Now, we repeat some of the above for the user's private entries 527 */ 528 if ((lc = login_getuserclass(pwd)) != NULL) { 529 mymask = setlogincontext(lc, pwd, mymask, flags); 530 login_close(lc); 531 } 532 533 /* Finally, set any umask we've found */ 534 if (flags & LOGIN_SETUMASK) 535 umask(mymask); 536 537 return (0); 538 } 539