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 * $Id: login_class.c,v 1.9 1998/07/28 01:30:16 ache Exp $ 25 */ 26 27 #include <stdio.h> 28 #include <stdlib.h> 29 #include <string.h> 30 #include <unistd.h> 31 #include <errno.h> 32 #include <sys/types.h> 33 #include <sys/stat.h> 34 #include <sys/time.h> 35 #include <sys/resource.h> 36 #include <fcntl.h> 37 #include <pwd.h> 38 #include <syslog.h> 39 #include <login_cap.h> 40 #include <paths.h> 41 #include <sys/rtprio.h> 42 43 44 #undef UNKNOWN 45 #define UNKNOWN "su" 46 47 48 static struct login_res { 49 const char *what; 50 rlim_t (*who)(login_cap_t *, const char *, rlim_t, rlim_t); 51 int why; 52 } resources[] = { 53 { "cputime", login_getcaptime, RLIMIT_CPU }, 54 { "filesize", login_getcapsize, RLIMIT_FSIZE }, 55 { "datasize", login_getcapsize, RLIMIT_DATA }, 56 { "stacksize", login_getcapsize, RLIMIT_STACK }, 57 { "memoryuse", login_getcapsize, RLIMIT_RSS }, 58 { "memorylocked", login_getcapsize, RLIMIT_MEMLOCK }, 59 { "maxproc", login_getcapnum, RLIMIT_NPROC }, 60 { "openfiles", login_getcapnum, RLIMIT_NOFILE }, 61 { "coredumpsize", login_getcapsize, RLIMIT_CORE }, 62 { NULL, 0, 0 } 63 }; 64 65 66 void 67 setclassresources(login_cap_t *lc) 68 { 69 struct login_res *lr; 70 71 if (lc == NULL) 72 return; 73 74 for (lr = resources; lr->what != NULL; ++lr) { 75 struct rlimit rlim; 76 77 /* 78 * The login.conf file can have <limit>, <limit>-max, and 79 * <limit>-cur entries. 80 * What we do is get the current current- and maximum- limits. 81 * Then, we try to get an entry for <limit> from the capability, 82 * using the current and max limits we just got as the 83 * default/error values. 84 * *Then*, we try looking for <limit>-cur and <limit>-max, 85 * again using the appropriate values as the default/error 86 * conditions. 87 */ 88 89 if (getrlimit(lr->why, &rlim) != 0) 90 syslog(LOG_ERR, "getting %s resource limit: %m", lr->what); 91 else { 92 char name_cur[40]; 93 char name_max[40]; 94 rlim_t rcur = rlim.rlim_cur; 95 rlim_t rmax = rlim.rlim_max; 96 97 sprintf(name_cur, "%s-cur", lr->what); 98 sprintf(name_max, "%s-max", lr->what); 99 100 rcur = (*lr->who)(lc, lr->what, rcur, rcur); 101 rmax = (*lr->who)(lc, lr->what, rmax, rmax); 102 rlim.rlim_cur = (*lr->who)(lc, name_cur, rcur, rcur); 103 rlim.rlim_max = (*lr->who)(lc, name_max, rmax, rmax); 104 105 if (setrlimit(lr->why, &rlim) == -1) 106 syslog(LOG_WARNING, "set class '%s' resource limit %s: %m", lc->lc_class, lr->what); 107 } 108 } 109 } 110 111 112 113 static struct login_vars { 114 const char *tag; 115 const char *var; 116 const char *def; 117 } pathvars[] = { 118 { "path", "PATH", NULL }, 119 { "cdpath", "CDPATH", NULL }, 120 { "manpath", "MANPATH", NULL }, 121 { NULL, NULL, NULL } 122 }, envars[] = { 123 { "lang", "LANG", NULL }, 124 { "charset", "MM_CHARSET", NULL }, 125 { "timezone", "TZ", NULL }, 126 { "term", "TERM", UNKNOWN }, 127 { NULL, NULL, NULL } 128 }; 129 130 static char * 131 substvar(char * var, const struct passwd * pwd, int hlen, int pch, int nlen) 132 { 133 char *np = NULL; 134 135 if (var != NULL) { 136 int tildes = 0; 137 int dollas = 0; 138 char *p; 139 140 if (pwd != NULL) { 141 /* Count the number of ~'s in var to substitute */ 142 p = var; 143 for (p = var; (p = strchr(p, '~')) != NULL; p++) 144 ++tildes; 145 /* Count the number of $'s in var to substitute */ 146 p = var; 147 for (p = var; (p = strchr(p, '$')) != NULL; p++) 148 ++dollas; 149 } 150 151 np = malloc(strlen(var) + (dollas * nlen) 152 - dollas + (tildes * (pch+hlen)) 153 - tildes + 1); 154 155 if (np != NULL) { 156 p = strcpy(np, var); 157 158 if (pwd != NULL) { 159 /* 160 * This loop does user username and homedir substitutions 161 * for unescaped $ (username) and ~ (homedir) 162 */ 163 while (*(p += strcspn(p, "~$")) != '\0') { 164 int l = strlen(p); 165 166 if (p > var && *(p-1) == '\\') /* Escaped: */ 167 memmove(p - 1, p, l + 1); /* Slide-out the backslash */ 168 else if (*p == '~') { 169 int v = pch && *(p+1) != '/'; /* Avoid double // */ 170 memmove(p + hlen + v, p + 1, l); /* Subst homedir */ 171 memmove(p, pwd->pw_dir, hlen); 172 if (v) 173 p[hlen] = '/'; 174 p += hlen + v; 175 } 176 else /* if (*p == '$') */ { 177 memmove(p + nlen, p + 1, l); /* Subst username */ 178 memmove(p, pwd->pw_name, nlen); 179 p += nlen; 180 } 181 } 182 } 183 } 184 } 185 186 return np; 187 } 188 189 190 void 191 setclassenvironment(login_cap_t *lc, const struct passwd * pwd, int paths) 192 { 193 struct login_vars *vars = paths ? pathvars : envars; 194 int hlen = pwd ? strlen(pwd->pw_dir) : 0; 195 int nlen = pwd ? strlen(pwd->pw_name) : 0; 196 char pch = 0; 197 198 if (hlen && pwd->pw_dir[hlen-1] != '/') 199 ++pch; 200 201 while (vars->tag != NULL) { 202 char * var = paths ? login_getpath(lc, vars->tag, NULL) 203 : login_getcapstr(lc, vars->tag, NULL, NULL); 204 205 char * np = substvar(var, pwd, hlen, pch, nlen); 206 207 if (np != NULL) { 208 setenv(vars->var, np, 1); 209 free(np); 210 } else if (vars->def != NULL) { 211 setenv(vars->var, vars->def, 0); 212 } 213 ++vars; 214 } 215 216 /* 217 * If we're not processing paths, then see if there is a setenv list by 218 * which the admin and/or user may set an arbitrary set of env vars. 219 */ 220 if (!paths) { 221 char **set_env = login_getcaplist(lc, "setenv", ","); 222 223 if (set_env != NULL) { 224 while (*set_env != NULL) { 225 char *p = strchr(*set_env, '='); 226 227 if (p != NULL) { /* Discard invalid entries */ 228 char *np; 229 230 *p++ = '\0'; 231 if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) { 232 setenv(*set_env, np, 1); 233 free(np); 234 } 235 } 236 ++set_env; 237 } 238 } 239 } 240 } 241 242 243 /* 244 * setclasscontext() 245 * 246 * For the login class <class>, set various class context values 247 * (limits, mainly) to the values for that class. Which values are 248 * set are controlled by <flags> -- see <login_class.h> for the 249 * possible values. 250 * 251 * setclasscontext() can only set resources, priority, and umask. 252 */ 253 254 int 255 setclasscontext(const char *classname, unsigned int flags) 256 { 257 int rc; 258 login_cap_t *lc; 259 260 lc = login_getclassbyname(classname, NULL); 261 262 flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY | 263 LOGIN_SETUMASK | LOGIN_SETPATH; 264 265 rc = lc ? setusercontext(lc, NULL, 0, flags) : -1; 266 login_close(lc); 267 return rc; 268 } 269 270 271 272 /* 273 * Private functionw which takes care of processing 274 */ 275 276 static mode_t 277 setlogincontext(login_cap_t *lc, const struct passwd *pwd, 278 mode_t mymask, unsigned long flags) 279 { 280 if (lc) { 281 /* Set resources */ 282 if (flags & LOGIN_SETRESOURCES) 283 setclassresources(lc); 284 /* See if there's a umask override */ 285 if (flags & LOGIN_SETUMASK) 286 mymask = (mode_t)login_getcapnum(lc, "umask", mymask, mymask); 287 /* Set paths */ 288 if (flags & LOGIN_SETPATH) 289 setclassenvironment(lc, pwd, 1); 290 /* Set environment */ 291 if (flags & LOGIN_SETENV) 292 setclassenvironment(lc, pwd, 0); 293 } 294 return mymask; 295 } 296 297 298 299 /* 300 * setusercontext() 301 * 302 * Given a login class <lc> and a user in <pwd>, with a uid <uid>, 303 * set the context as in setclasscontext(). <flags> controls which 304 * values are set. 305 * 306 * The difference between setclasscontext() and setusercontext() is 307 * that the former sets things up for an already-existing process, 308 * while the latter sets things up from a root context. Such as might 309 * be called from login(1). 310 * 311 */ 312 313 int 314 setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags) 315 { 316 quad_t p; 317 mode_t mymask; 318 login_cap_t *llc = NULL; 319 #ifndef __NETBSD_SYSCALLS 320 struct rtprio rtp; 321 #endif 322 323 if (lc == NULL) { 324 if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL) 325 llc = lc; /* free this when we're done */ 326 } 327 328 if (flags & LOGIN_SETPATH) 329 pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH; 330 331 /* we need a passwd entry to set these */ 332 if (pwd == NULL) 333 flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN); 334 335 /* Set the process priority */ 336 if (flags & LOGIN_SETPRIORITY) { 337 p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI); 338 339 if(p > PRIO_MAX) { 340 #ifndef __NETBSD_SYSCALLS 341 rtp.type = RTP_PRIO_IDLE; 342 rtp.prio = p - PRIO_MAX - 1; 343 p = (rtp.prio > RTP_PRIO_MAX) ? 31 : p; 344 if(rtprio(RTP_SET, 0, &rtp)) 345 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 346 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 347 #endif 348 } else if(p < PRIO_MIN) { 349 #ifndef __NETBSD_SYSCALLS 350 rtp.type = RTP_PRIO_REALTIME; 351 rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX); 352 p = (rtp.prio > RTP_PRIO_MAX) ? 1 : p; 353 if(rtprio(RTP_SET, 0, &rtp)) 354 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 355 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 356 #endif 357 } else { 358 if (setpriority(PRIO_PROCESS, 0, (int)p) != 0) 359 syslog(LOG_WARNING, "setpriority '%s' (%s): %m", 360 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 361 } 362 } 363 364 /* Setup the user's group permissions */ 365 if (flags & LOGIN_SETGROUP) { 366 if (setgid(pwd->pw_gid) != 0) { 367 syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid); 368 login_close(llc); 369 return -1; 370 } 371 if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) { 372 syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name, 373 (u_long)pwd->pw_gid); 374 login_close(llc); 375 return -1; 376 } 377 } 378 379 /* Set the sessions login */ 380 if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) { 381 syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name); 382 login_close(llc); 383 return -1; 384 } 385 386 mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0; 387 mymask = setlogincontext(lc, pwd, mymask, flags); 388 login_close(llc); 389 390 /* This needs to be done after anything that needs root privs */ 391 if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) { 392 syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid); 393 return -1; /* Paranoia again */ 394 } 395 396 /* 397 * Now, we repeat some of the above for the user's private entries 398 */ 399 if ((lc = login_getuserclass(pwd)) != NULL) { 400 mymask = setlogincontext(lc, pwd, mymask, flags); 401 login_close(lc); 402 } 403 404 /* Finally, set any umask we've found */ 405 if (flags & LOGIN_SETUMASK) 406 umask(mymask); 407 408 return 0; 409 } 410 411