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 * $FreeBSD: src/lib/libutil/login_class.c,v 1.14.2.3 2002/08/06 07:07:52 ache Exp $ 25 * $DragonFly: src/lib/libutil/login_class.c,v 1.5 2006/01/12 13:43:10 corecode Exp $ 26 */ 27 28 #include <sys/types.h> 29 #include <sys/stat.h> 30 #include <sys/time.h> 31 #include <sys/resource.h> 32 #include <sys/rtprio.h> 33 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <paths.h> 37 #include <pwd.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <syslog.h> 42 #include <unistd.h> 43 44 #include "login_cap.h" 45 46 47 static struct login_res { 48 const char *what; 49 rlim_t (*who)(login_cap_t *, const char *, rlim_t, rlim_t); 50 int why; 51 } resources[] = { 52 { "cputime", login_getcaptime, RLIMIT_CPU }, 53 { "filesize", login_getcapsize, RLIMIT_FSIZE }, 54 { "datasize", login_getcapsize, RLIMIT_DATA }, 55 { "stacksize", login_getcapsize, RLIMIT_STACK }, 56 { "memoryuse", login_getcapsize, RLIMIT_RSS }, 57 { "memorylocked", login_getcapsize, RLIMIT_MEMLOCK }, 58 { "maxproc", login_getcapnum, RLIMIT_NPROC }, 59 { "openfiles", login_getcapnum, RLIMIT_NOFILE }, 60 { "coredumpsize", login_getcapsize, RLIMIT_CORE }, 61 { "sbsize", login_getcapsize, RLIMIT_SBSIZE }, 62 { "vmemoryuse", login_getcapsize, RLIMIT_VMEM }, 63 #ifdef RLIMIT_POSIXLOCKS 64 { "posixlocks", login_getcapnum, RLIMIT_POSIXLOCKS }, 65 #endif 66 { NULL, 0, 0 } 67 }; 68 69 70 void 71 setclassresources(login_cap_t *lc) 72 { 73 struct login_res *lr; 74 75 if (lc == NULL) 76 return; 77 78 for (lr = resources; lr->what != NULL; ++lr) { 79 struct rlimit rlim; 80 81 /* 82 * The login.conf file can have <limit>, <limit>-max, and 83 * <limit>-cur entries. 84 * What we do is get the current current- and maximum- limits. 85 * Then, we try to get an entry for <limit> from the capability, 86 * using the current and max limits we just got as the 87 * default/error values. 88 * *Then*, we try looking for <limit>-cur and <limit>-max, 89 * again using the appropriate values as the default/error 90 * conditions. 91 */ 92 93 if (getrlimit(lr->why, &rlim) != 0) 94 syslog(LOG_ERR, "getting %s resource limit: %m", lr->what); 95 else { 96 char name_cur[40]; 97 char name_max[40]; 98 rlim_t rcur = rlim.rlim_cur; 99 rlim_t rmax = rlim.rlim_max; 100 101 sprintf(name_cur, "%s-cur", lr->what); 102 sprintf(name_max, "%s-max", lr->what); 103 104 rcur = (*lr->who)(lc, lr->what, rcur, rcur); 105 rmax = (*lr->who)(lc, lr->what, rmax, rmax); 106 rlim.rlim_cur = (*lr->who)(lc, name_cur, rcur, rcur); 107 rlim.rlim_max = (*lr->who)(lc, name_max, rmax, rmax); 108 109 if (setrlimit(lr->why, &rlim) == -1) 110 syslog(LOG_WARNING, "set class '%s' resource limit %s: %m", lc->lc_class, lr->what); 111 } 112 } 113 } 114 115 116 117 static struct login_vars { 118 const char *tag; 119 const char *var; 120 const char *def; 121 int overwrite; 122 } pathvars[] = { 123 { "path", "PATH", NULL, 1}, 124 { "cdpath", "CDPATH", NULL, 1}, 125 { "manpath", "MANPATH", NULL, 1}, 126 { NULL, NULL, NULL, 0} 127 }, envars[] = { 128 { "lang", "LANG", NULL, 1}, 129 { "charset", "MM_CHARSET", NULL, 1}, 130 { "timezone", "TZ", NULL, 1}, 131 { "term", "TERM", NULL, 0}, 132 { NULL, NULL, NULL, 0} 133 }; 134 135 static char * 136 substvar(char * var, const struct passwd * pwd, int hlen, int pch, int nlen) 137 { 138 char *np = NULL; 139 140 if (var != NULL) { 141 int tildes = 0; 142 int dollas = 0; 143 char *p; 144 145 if (pwd != NULL) { 146 /* Count the number of ~'s in var to substitute */ 147 p = var; 148 for (p = var; (p = strchr(p, '~')) != NULL; p++) 149 ++tildes; 150 /* Count the number of $'s in var to substitute */ 151 p = var; 152 for (p = var; (p = strchr(p, '$')) != NULL; p++) 153 ++dollas; 154 } 155 156 np = malloc(strlen(var) + (dollas * nlen) 157 - dollas + (tildes * (pch+hlen)) 158 - tildes + 1); 159 160 if (np != NULL) { 161 p = strcpy(np, var); 162 163 if (pwd != NULL) { 164 /* 165 * This loop does user username and homedir substitutions 166 * for unescaped $ (username) and ~ (homedir) 167 */ 168 while (*(p += strcspn(p, "~$")) != '\0') { 169 int l = strlen(p); 170 171 if (p > np && *(p-1) == '\\') /* Escaped: */ 172 memmove(p - 1, p, l + 1); /* Slide-out the backslash */ 173 else if (*p == '~') { 174 int v = pch && *(p+1) != '/'; /* Avoid double // */ 175 memmove(p + hlen + v, p + 1, l); /* Subst homedir */ 176 memmove(p, pwd->pw_dir, hlen); 177 if (v) 178 p[hlen] = '/'; 179 p += hlen + v; 180 } 181 else /* if (*p == '$') */ { 182 memmove(p + nlen, p + 1, l); /* Subst username */ 183 memmove(p, pwd->pw_name, nlen); 184 p += nlen; 185 } 186 } 187 } 188 } 189 } 190 191 return np; 192 } 193 194 195 int 196 setclassenvironment(login_cap_t *lc, const struct passwd * pwd, int paths) 197 { 198 struct login_vars *vars = paths ? pathvars : envars; 199 int hlen = pwd ? strlen(pwd->pw_dir) : 0; 200 int nlen = pwd ? strlen(pwd->pw_name) : 0; 201 char pch = 0; 202 203 if (hlen && pwd->pw_dir[hlen-1] != '/') 204 ++pch; 205 206 while (vars->tag != NULL) { 207 char * var = paths ? login_getpath(lc, vars->tag, NULL) 208 : login_getcapstr(lc, vars->tag, NULL, NULL); 209 210 char * np = substvar(var, pwd, hlen, pch, nlen); 211 212 if (np != NULL) { 213 if (setenv(vars->var, np, vars->overwrite) == -1) { 214 syslog(LOG_ERR, "setclassenvironment: %m"); 215 free(np); 216 return -1; 217 } 218 free(np); 219 } else if (vars->def != NULL) { 220 if (setenv(vars->var, vars->def, 0) == -1) { 221 syslog(LOG_ERR, "setclassenvironment: %m"); 222 return -1; 223 } 224 } 225 ++vars; 226 } 227 228 /* 229 * If we're not processing paths, then see if there is a setenv list by 230 * which the admin and/or user may set an arbitrary set of env vars. 231 */ 232 if (!paths) { 233 char **set_env = login_getcaplist(lc, "setenv", ","); 234 235 if (set_env != NULL) { 236 while (*set_env != NULL) { 237 char *p = strchr(*set_env, '='); 238 239 if (p != NULL) { /* Discard invalid entries */ 240 char *np; 241 242 *p++ = '\0'; 243 if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) { 244 if (setenv(*set_env, np, 1) == -1) { 245 free(np); 246 return -1; 247 } 248 free(np); 249 } 250 } 251 ++set_env; 252 } 253 } 254 } 255 return 0; 256 } 257 258 259 /* 260 * setclasscontext() 261 * 262 * For the login class <class>, set various class context values 263 * (limits, mainly) to the values for that class. Which values are 264 * set are controlled by <flags> -- see <login_class.h> for the 265 * possible values. 266 * 267 * setclasscontext() can only set resources, priority, and umask. 268 */ 269 270 int 271 setclasscontext(const char *classname, unsigned int flags) 272 { 273 int rc; 274 login_cap_t *lc; 275 276 lc = login_getclassbyname(classname, NULL); 277 278 flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY | 279 LOGIN_SETUMASK | LOGIN_SETPATH; 280 281 rc = lc ? setusercontext(lc, NULL, 0, flags) : -1; 282 login_close(lc); 283 return rc; 284 } 285 286 287 288 /* 289 * Private functionw which takes care of processing 290 */ 291 292 static mode_t 293 setlogincontext(login_cap_t *lc, const struct passwd *pwd, 294 mode_t mymask, unsigned long flags, int *errcode) 295 { 296 *errcode = 0; 297 if (lc) { 298 /* Set resources */ 299 if (flags & LOGIN_SETRESOURCES) 300 setclassresources(lc); 301 /* See if there's a umask override */ 302 if (flags & LOGIN_SETUMASK) 303 mymask = (mode_t)login_getcapnum(lc, "umask", mymask, mymask); 304 /* Set paths */ 305 if (flags & LOGIN_SETPATH) { 306 if (setclassenvironment(lc, pwd, 1) == -1) 307 *errcode = -1; 308 } 309 /* Set environment */ 310 if (flags & LOGIN_SETENV) { 311 if (setclassenvironment(lc, pwd, 0) == -1) 312 *errcode = -1; 313 } 314 } 315 return mymask; 316 } 317 318 319 320 /* 321 * setusercontext() 322 * 323 * Given a login class <lc> and a user in <pwd>, with a uid <uid>, 324 * set the context as in setclasscontext(). <flags> controls which 325 * values are set. 326 * 327 * The difference between setclasscontext() and setusercontext() is 328 * that the former sets things up for an already-existing process, 329 * while the latter sets things up from a root context. Such as might 330 * be called from login(1). 331 * 332 */ 333 334 int 335 setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags) 336 { 337 quad_t p; 338 mode_t mymask; 339 login_cap_t *llc = NULL; 340 #ifndef __NETBSD_SYSCALLS 341 struct rtprio rtp; 342 #endif 343 int errcode; 344 345 if (lc == NULL) { 346 if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL) 347 llc = lc; /* free this when we're done */ 348 } 349 350 if (flags & LOGIN_SETPATH) 351 pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH; 352 353 /* we need a passwd entry to set these */ 354 if (pwd == NULL) 355 flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN); 356 357 /* Set the process priority */ 358 if (flags & LOGIN_SETPRIORITY) { 359 p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI); 360 361 if(p > PRIO_MAX) { 362 #ifndef __NETBSD_SYSCALLS 363 rtp.type = RTP_PRIO_IDLE; 364 rtp.prio = p - PRIO_MAX - 1; 365 p = (rtp.prio > RTP_PRIO_MAX) ? 31 : p; 366 if(rtprio(RTP_SET, 0, &rtp)) 367 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 368 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 369 #endif 370 } else if(p < PRIO_MIN) { 371 #ifndef __NETBSD_SYSCALLS 372 rtp.type = RTP_PRIO_REALTIME; 373 rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX); 374 p = (rtp.prio > RTP_PRIO_MAX) ? 1 : p; 375 if(rtprio(RTP_SET, 0, &rtp)) 376 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 377 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 378 #endif 379 } else { 380 if (setpriority(PRIO_PROCESS, 0, (int)p) != 0) 381 syslog(LOG_WARNING, "setpriority '%s' (%s): %m", 382 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 383 } 384 } 385 386 /* Setup the user's group permissions */ 387 if (flags & LOGIN_SETGROUP) { 388 if (setgid(pwd->pw_gid) != 0) { 389 syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid); 390 login_close(llc); 391 return -1; 392 } 393 if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) { 394 syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name, 395 (u_long)pwd->pw_gid); 396 login_close(llc); 397 return -1; 398 } 399 } 400 401 /* Set the sessions login */ 402 if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) { 403 syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name); 404 login_close(llc); 405 return -1; 406 } 407 408 mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0; 409 mymask = setlogincontext(lc, pwd, mymask, flags, &errcode); 410 if (errcode == -1) { 411 login_close(llc); 412 return -1; 413 } 414 login_close(llc); 415 416 /* This needs to be done after anything that needs root privs */ 417 if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) { 418 syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid); 419 return -1; /* Paranoia again */ 420 } 421 422 /* 423 * Now, we repeat some of the above for the user's private entries 424 */ 425 if ((lc = login_getuserclass(pwd)) != NULL) { 426 mymask = setlogincontext(lc, pwd, mymask, flags, &errcode); 427 if (errcode == -1) { 428 login_close(lc); 429 return -1; 430 } 431 login_close(lc); 432 } 433 434 /* Finally, set any umask we've found */ 435 if (flags & LOGIN_SETUMASK) 436 umask(mymask); 437 438 return 0; 439 } 440 441