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