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 1.4 2005/03/04 04:31:11 cpressey 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 void 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 setenv(vars->var, np, vars->overwrite); 214 free(np); 215 } else if (vars->def != NULL) { 216 setenv(vars->var, vars->def, 0); 217 } 218 ++vars; 219 } 220 221 /* 222 * If we're not processing paths, then see if there is a setenv list by 223 * which the admin and/or user may set an arbitrary set of env vars. 224 */ 225 if (!paths) { 226 char **set_env = login_getcaplist(lc, "setenv", ","); 227 228 if (set_env != NULL) { 229 while (*set_env != NULL) { 230 char *p = strchr(*set_env, '='); 231 232 if (p != NULL) { /* Discard invalid entries */ 233 char *np; 234 235 *p++ = '\0'; 236 if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) { 237 setenv(*set_env, np, 1); 238 free(np); 239 } 240 } 241 ++set_env; 242 } 243 } 244 } 245 } 246 247 248 /* 249 * setclasscontext() 250 * 251 * For the login class <class>, set various class context values 252 * (limits, mainly) to the values for that class. Which values are 253 * set are controlled by <flags> -- see <login_class.h> for the 254 * possible values. 255 * 256 * setclasscontext() can only set resources, priority, and umask. 257 */ 258 259 int 260 setclasscontext(const char *classname, unsigned int flags) 261 { 262 int rc; 263 login_cap_t *lc; 264 265 lc = login_getclassbyname(classname, NULL); 266 267 flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY | 268 LOGIN_SETUMASK | LOGIN_SETPATH; 269 270 rc = lc ? setusercontext(lc, NULL, 0, flags) : -1; 271 login_close(lc); 272 return rc; 273 } 274 275 276 277 /* 278 * Private functionw which takes care of processing 279 */ 280 281 static mode_t 282 setlogincontext(login_cap_t *lc, const struct passwd *pwd, 283 mode_t mymask, unsigned long flags) 284 { 285 if (lc) { 286 /* Set resources */ 287 if (flags & LOGIN_SETRESOURCES) 288 setclassresources(lc); 289 /* See if there's a umask override */ 290 if (flags & LOGIN_SETUMASK) 291 mymask = (mode_t)login_getcapnum(lc, "umask", mymask, mymask); 292 /* Set paths */ 293 if (flags & LOGIN_SETPATH) 294 setclassenvironment(lc, pwd, 1); 295 /* Set environment */ 296 if (flags & LOGIN_SETENV) 297 setclassenvironment(lc, pwd, 0); 298 } 299 return mymask; 300 } 301 302 303 304 /* 305 * setusercontext() 306 * 307 * Given a login class <lc> and a user in <pwd>, with a uid <uid>, 308 * set the context as in setclasscontext(). <flags> controls which 309 * values are set. 310 * 311 * The difference between setclasscontext() and setusercontext() is 312 * that the former sets things up for an already-existing process, 313 * while the latter sets things up from a root context. Such as might 314 * be called from login(1). 315 * 316 */ 317 318 int 319 setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags) 320 { 321 quad_t p; 322 mode_t mymask; 323 login_cap_t *llc = NULL; 324 #ifndef __NETBSD_SYSCALLS 325 struct rtprio rtp; 326 #endif 327 328 if (lc == NULL) { 329 if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL) 330 llc = lc; /* free this when we're done */ 331 } 332 333 if (flags & LOGIN_SETPATH) 334 pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH; 335 336 /* we need a passwd entry to set these */ 337 if (pwd == NULL) 338 flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN); 339 340 /* Set the process priority */ 341 if (flags & LOGIN_SETPRIORITY) { 342 p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI); 343 344 if(p > PRIO_MAX) { 345 #ifndef __NETBSD_SYSCALLS 346 rtp.type = RTP_PRIO_IDLE; 347 rtp.prio = p - PRIO_MAX - 1; 348 p = (rtp.prio > RTP_PRIO_MAX) ? 31 : p; 349 if(rtprio(RTP_SET, 0, &rtp)) 350 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 351 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 352 #endif 353 } else if(p < PRIO_MIN) { 354 #ifndef __NETBSD_SYSCALLS 355 rtp.type = RTP_PRIO_REALTIME; 356 rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX); 357 p = (rtp.prio > RTP_PRIO_MAX) ? 1 : p; 358 if(rtprio(RTP_SET, 0, &rtp)) 359 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 360 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 361 #endif 362 } else { 363 if (setpriority(PRIO_PROCESS, 0, (int)p) != 0) 364 syslog(LOG_WARNING, "setpriority '%s' (%s): %m", 365 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 366 } 367 } 368 369 /* Setup the user's group permissions */ 370 if (flags & LOGIN_SETGROUP) { 371 if (setgid(pwd->pw_gid) != 0) { 372 syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid); 373 login_close(llc); 374 return -1; 375 } 376 if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) { 377 syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name, 378 (u_long)pwd->pw_gid); 379 login_close(llc); 380 return -1; 381 } 382 } 383 384 /* Set the sessions login */ 385 if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) { 386 syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name); 387 login_close(llc); 388 return -1; 389 } 390 391 mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0; 392 mymask = setlogincontext(lc, pwd, mymask, flags); 393 login_close(llc); 394 395 /* This needs to be done after anything that needs root privs */ 396 if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) { 397 syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid); 398 return -1; /* Paranoia again */ 399 } 400 401 /* 402 * Now, we repeat some of the above for the user's private entries 403 */ 404 if ((lc = login_getuserclass(pwd)) != NULL) { 405 mymask = setlogincontext(lc, pwd, mymask, flags); 406 login_close(lc); 407 } 408 409 /* Finally, set any umask we've found */ 410 if (flags & LOGIN_SETUMASK) 411 umask(mymask); 412 413 return 0; 414 } 415 416