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 for (p = var; (p = strchr(p, '~')) != NULL; p++) 148 ++tildes; 149 /* Count the number of $'s in var to substitute */ 150 for (p = var; (p = strchr(p, '$')) != NULL; p++) 151 ++dollas; 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 int 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 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 if (setenv(vars->var, np, vars->overwrite) == -1) { 212 syslog(LOG_ERR, "setclassenvironment: %m"); 213 free(np); 214 return -1; 215 } 216 free(np); 217 } else if (vars->def != NULL) { 218 if (setenv(vars->var, vars->def, 0) == -1) { 219 syslog(LOG_ERR, "setclassenvironment: %m"); 220 return -1; 221 } 222 } 223 ++vars; 224 } 225 226 /* 227 * If we're not processing paths, then see if there is a setenv list by 228 * which the admin and/or user may set an arbitrary set of env vars. 229 */ 230 if (!paths) { 231 char **set_env = login_getcaplist(lc, "setenv", ","); 232 233 if (set_env != NULL) { 234 while (*set_env != NULL) { 235 char *p = strchr(*set_env, '='); 236 237 if (p != NULL) { /* Discard invalid entries */ 238 char *np; 239 240 *p++ = '\0'; 241 if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) { 242 if (setenv(*set_env, np, 1) == -1) { 243 free(np); 244 return -1; 245 } 246 free(np); 247 } 248 } 249 ++set_env; 250 } 251 } 252 } 253 return 0; 254 } 255 256 257 /* 258 * setclasscontext() 259 * 260 * For the login class <class>, set various class context values 261 * (limits, mainly) to the values for that class. Which values are 262 * set are controlled by <flags> -- see <login_class.h> for the 263 * possible values. 264 * 265 * setclasscontext() can only set resources, priority, and umask. 266 */ 267 268 int 269 setclasscontext(const char *classname, unsigned int flags) 270 { 271 int rc; 272 login_cap_t *lc; 273 274 lc = login_getclassbyname(classname, NULL); 275 276 flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY | 277 LOGIN_SETUMASK | LOGIN_SETPATH; 278 279 rc = lc ? setusercontext(lc, NULL, 0, flags) : -1; 280 login_close(lc); 281 return rc; 282 } 283 284 285 286 /* 287 * Private functionw which takes care of processing 288 */ 289 290 static mode_t 291 setlogincontext(login_cap_t *lc, const struct passwd *pwd, 292 mode_t mymask, unsigned long flags, int *errcode) 293 { 294 *errcode = 0; 295 if (lc) { 296 /* Set resources */ 297 if (flags & LOGIN_SETRESOURCES) 298 setclassresources(lc); 299 /* See if there's a umask override */ 300 if (flags & LOGIN_SETUMASK) 301 mymask = (mode_t)login_getcapnum(lc, "umask", mymask, mymask); 302 /* Set paths */ 303 if (flags & LOGIN_SETPATH) { 304 if (setclassenvironment(lc, pwd, 1) == -1) 305 *errcode = -1; 306 } 307 /* Set environment */ 308 if (flags & LOGIN_SETENV) { 309 if (setclassenvironment(lc, pwd, 0) == -1) 310 *errcode = -1; 311 } 312 } 313 return mymask; 314 } 315 316 317 318 /* 319 * setusercontext() 320 * 321 * Given a login class <lc> and a user in <pwd>, with a uid <uid>, 322 * set the context as in setclasscontext(). <flags> controls which 323 * values are set. 324 * 325 * The difference between setclasscontext() and setusercontext() is 326 * that the former sets things up for an already-existing process, 327 * while the latter sets things up from a root context. Such as might 328 * be called from login(1). 329 * 330 */ 331 332 int 333 setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags) 334 { 335 quad_t p; 336 mode_t mymask; 337 login_cap_t *llc = NULL; 338 #ifndef __NETBSD_SYSCALLS 339 struct rtprio rtp; 340 #endif 341 int errcode; 342 343 if (lc == NULL) { 344 if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL) 345 llc = lc; /* free this when we're done */ 346 } 347 348 if (flags & LOGIN_SETPATH) 349 pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH; 350 351 /* we need a passwd entry to set these */ 352 if (pwd == NULL) 353 flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN); 354 355 /* Set the process priority */ 356 if (flags & LOGIN_SETPRIORITY) { 357 p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI); 358 359 if(p > PRIO_MAX) { 360 #ifndef __NETBSD_SYSCALLS 361 rtp.type = RTP_PRIO_IDLE; 362 rtp.prio = p - PRIO_MAX - 1; 363 if(rtprio(RTP_SET, 0, &rtp)) 364 syslog(LOG_WARNING, "rtprio (%s): %m", 365 lc ? lc->lc_class : LOGIN_DEFCLASS); 366 #endif 367 } else if(p < PRIO_MIN) { 368 #ifndef __NETBSD_SYSCALLS 369 rtp.type = RTP_PRIO_REALTIME; 370 rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX); 371 if(rtprio(RTP_SET, 0, &rtp)) 372 syslog(LOG_WARNING, "rtprio (%s): %m", 373 lc ? lc->lc_class : LOGIN_DEFCLASS); 374 #endif 375 } else { 376 if (setpriority(PRIO_PROCESS, 0, (int)p) != 0) 377 syslog(LOG_WARNING, "setpriority (%s): %m", 378 lc ? lc->lc_class : LOGIN_DEFCLASS); 379 } 380 } 381 382 /* Setup the user's group permissions */ 383 if (flags & LOGIN_SETGROUP) { 384 if (setgid(pwd->pw_gid) != 0) { 385 syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid); 386 login_close(llc); 387 return -1; 388 } 389 if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) { 390 syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name, 391 (u_long)pwd->pw_gid); 392 login_close(llc); 393 return -1; 394 } 395 } 396 397 /* Set the sessions login */ 398 if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) { 399 syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name); 400 login_close(llc); 401 return -1; 402 } 403 404 mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0; 405 mymask = setlogincontext(lc, pwd, mymask, flags, &errcode); 406 if (errcode == -1) { 407 login_close(llc); 408 return -1; 409 } 410 login_close(llc); 411 412 /* This needs to be done after anything that needs root privs */ 413 if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) { 414 syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid); 415 return -1; /* Paranoia again */ 416 } 417 418 /* 419 * Now, we repeat some of the above for the user's private entries 420 */ 421 if ((lc = login_getuserclass(pwd)) != NULL) { 422 mymask = setlogincontext(lc, pwd, mymask, flags, &errcode); 423 if (errcode == -1) { 424 login_close(lc); 425 return -1; 426 } 427 login_close(lc); 428 } 429 430 /* Finally, set any umask we've found */ 431 if (flags & LOGIN_SETUMASK) 432 umask(mymask); 433 434 return 0; 435 } 436 437