su.c revision 1.29
1 /* $NetBSD: su.c,v 1.29 1999/02/20 00:20:59 scottr Exp $ */ 2 3 /* 4 * Copyright (c) 1988 The Regents of the University of California. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #ifndef lint 38 __COPYRIGHT( 39 "@(#) Copyright (c) 1988 The Regents of the University of California.\n\ 40 All rights reserved.\n"); 41 #endif /* not lint */ 42 43 #ifndef lint 44 #if 0 45 static char sccsid[] = "@(#)su.c 8.3 (Berkeley) 4/2/94";*/ 46 #else 47 __RCSID("$NetBSD: su.c,v 1.29 1999/02/20 00:20:59 scottr Exp $"); 48 #endif 49 #endif /* not lint */ 50 51 #include <sys/param.h> 52 #include <sys/time.h> 53 #include <sys/resource.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <grp.h> 57 #include <paths.h> 58 #include <pwd.h> 59 #include <stdio.h> 60 #ifdef SKEY 61 #include <skey.h> 62 #endif 63 #include <stdlib.h> 64 #include <string.h> 65 #include <syslog.h> 66 #include <time.h> 67 #include <tzfile.h> 68 #include <unistd.h> 69 70 #ifdef KERBEROS 71 #include <kerberosIV/des.h> 72 #include <kerberosIV/krb.h> 73 #include <netdb.h> 74 75 #define ARGSTR "-Kflm" 76 77 int use_kerberos = 1; 78 79 static int kerberos __P((char *, char *, int)); 80 static int koktologin __P((char *, char *, char *)); 81 82 #else 83 #define ARGSTR "-flm" 84 #endif 85 86 #ifndef SUGROUP 87 #define SUGROUP "wheel" 88 #endif 89 90 91 int main __P((int, char **)); 92 93 static int chshell __P((const char *)); 94 static char *ontty __P((void)); 95 96 97 int 98 main(argc, argv) 99 int argc; 100 char **argv; 101 { 102 extern char *__progname; 103 extern char **environ; 104 struct passwd *pwd; 105 char *p; 106 struct group *gr; 107 #ifdef BSD4_4 108 struct timeval tp; 109 #endif 110 uid_t ruid; 111 int asme, ch, asthem, fastlogin, prio; 112 enum { UNSET, YES, NO } iscsh = UNSET; 113 char *user, *shell, *avshell, *username, *cleanenv[10], **np; 114 char shellbuf[MAXPATHLEN], avshellbuf[MAXPATHLEN]; 115 116 asme = asthem = fastlogin = 0; 117 shell = NULL; 118 while ((ch = getopt(argc, argv, ARGSTR)) != -1) 119 switch((char)ch) { 120 #ifdef KERBEROS 121 case 'K': 122 use_kerberos = 0; 123 break; 124 #endif 125 case 'f': 126 fastlogin = 1; 127 break; 128 case '-': 129 case 'l': 130 asme = 0; 131 asthem = 1; 132 break; 133 case 'm': 134 asme = 1; 135 asthem = 0; 136 break; 137 case '?': 138 default: 139 (void)fprintf(stderr, 140 "Usage: %s [%s] [login [shell arguments]]\n", 141 __progname, ARGSTR); 142 exit(1); 143 } 144 argv += optind; 145 146 errno = 0; 147 prio = getpriority(PRIO_PROCESS, 0); 148 if (errno) 149 prio = 0; 150 (void)setpriority(PRIO_PROCESS, 0, -2); 151 openlog("su", LOG_CONS, 0); 152 153 /* get current login name and shell */ 154 ruid = getuid(); 155 username = getlogin(); 156 if (username == NULL || (pwd = getpwnam(username)) == NULL || 157 pwd->pw_uid != ruid) 158 pwd = getpwuid(ruid); 159 if (pwd == NULL) 160 errx(1, "who are you?"); 161 username = strdup(pwd->pw_name); 162 if (username == NULL) 163 err(1, "strdup"); 164 165 if (asme) { 166 if (pwd->pw_shell && *pwd->pw_shell) { 167 shell = strncpy(shellbuf, pwd->pw_shell, 168 sizeof(shellbuf) - 1); 169 shellbuf[sizeof(shellbuf) - 1] = '\0'; 170 } else { 171 shell = _PATH_BSHELL; 172 iscsh = NO; 173 } 174 } 175 /* get target login information, default to root */ 176 user = *argv ? *argv : "root"; 177 np = *argv ? argv : argv-1; 178 179 if ((pwd = getpwnam(user)) == NULL) 180 errx(1, "unknown login %s", user); 181 182 if (ruid 183 #ifdef KERBEROS 184 && (!use_kerberos || kerberos(username, user, pwd->pw_uid)) 185 #endif 186 ) { 187 /* 188 * Only allow those in group SUGROUP to su to root, 189 * but only if that group has any members. 190 * If SUGROUP has no members, allow anyone to su root 191 */ 192 if (pwd->pw_uid == 0 && 193 (gr = getgrnam(SUGROUP)) && *gr->gr_mem) { 194 char **g; 195 196 for (g = gr->gr_mem; ; g++) { 197 if (*g == NULL) 198 errx(1, 199 "you are not listed in the correct secondary group (%s) to su %s.", 200 SUGROUP, user); 201 if (strcmp(username, *g) == 0) 202 break; 203 } 204 } 205 /* if target requires a password, verify it */ 206 if (*pwd->pw_passwd) { 207 p = getpass("Password:"); 208 #ifdef SKEY 209 if (strcasecmp(p, "s/key") == 0) { 210 if (skey_haskey(user)) 211 errx(1, "Sorry, you have no s/key."); 212 else { 213 if (skey_authenticate(user)) { 214 goto badlogin; 215 } 216 } 217 218 } else 219 #endif 220 if (strcmp(pwd->pw_passwd, crypt(p, pwd->pw_passwd))) { 221 #ifdef SKEY 222 badlogin: 223 #endif 224 fprintf(stderr, "Sorry\n"); 225 syslog(LOG_AUTH|LOG_WARNING, 226 "BAD SU %s to %s%s", username, 227 user, ontty()); 228 exit(1); 229 } 230 } 231 } 232 233 if (asme) { 234 /* if asme and non-standard target shell, must be root */ 235 if (!chshell(pwd->pw_shell) && ruid) 236 errx(1,"permission denied (shell)."); 237 } else if (pwd->pw_shell && *pwd->pw_shell) { 238 shell = pwd->pw_shell; 239 iscsh = UNSET; 240 } else { 241 shell = _PATH_BSHELL; 242 iscsh = NO; 243 } 244 245 if ((p = strrchr(shell, '/')) != NULL) 246 avshell = p+1; 247 else 248 avshell = shell; 249 250 /* if we're forking a csh, we want to slightly muck the args */ 251 if (iscsh == UNSET) 252 iscsh = strstr(avshell, "csh") ? YES : NO; 253 254 /* set permissions */ 255 if (setgid(pwd->pw_gid) < 0) 256 err(1, "setgid"); 257 if (initgroups(user, pwd->pw_gid)) 258 errx(1, "initgroups failed"); 259 if (setuid(pwd->pw_uid) < 0) 260 err(1, "setuid"); 261 262 if (!asme) { 263 if (asthem) { 264 p = getenv("TERM"); 265 cleanenv[0] = NULL; 266 environ = cleanenv; 267 (void)setenv("PATH", _PATH_DEFPATH, 1); 268 if (p) 269 (void)setenv("TERM", p, 1); 270 if (chdir(pwd->pw_dir) < 0) 271 errx(1, "no directory"); 272 } 273 if (asthem || pwd->pw_uid) 274 (void)setenv("USER", pwd->pw_name, 1); 275 (void)setenv("HOME", pwd->pw_dir, 1); 276 (void)setenv("SHELL", shell, 1); 277 } 278 279 if (iscsh == YES) { 280 if (fastlogin) 281 *np-- = "-f"; 282 if (asme) 283 *np-- = "-m"; 284 } 285 286 if (asthem) { 287 avshellbuf[0] = '-'; 288 (void)strncpy(avshellbuf+1, avshell, sizeof(avshellbuf) - 2); 289 avshell = avshellbuf; 290 } else if (iscsh == YES) { 291 /* csh strips the first character... */ 292 avshellbuf[0] = '_'; 293 (void)strncpy(avshellbuf+1, avshell, sizeof(avshellbuf) - 2); 294 avshell = avshellbuf; 295 } 296 *np = avshell; 297 298 #ifdef BSD4_4 299 if (pwd->pw_change || pwd->pw_expire) 300 (void)gettimeofday(&tp, (struct timezone *)NULL); 301 if (pwd->pw_change) { 302 if (tp.tv_sec >= pwd->pw_change) { 303 (void)printf("%s -- %s's password has expired.\n", 304 (ruid ? "Sorry" : "Note"), user); 305 if (ruid != 0) 306 exit(1); 307 } else if (pwd->pw_change - tp.tv_sec < 308 _PASSWORD_WARNDAYS * SECSPERDAY) 309 (void)printf("Warning: %s's password expires on %s", 310 user, ctime(&pwd->pw_change)); 311 } 312 if (pwd->pw_expire) { 313 if (tp.tv_sec >= pwd->pw_expire) { 314 (void)printf("%s -- %s's account has expired.\n", 315 (ruid ? "Sorry" : "Note"), user); 316 if (ruid != 0) 317 exit(1); 318 } else if (pwd->pw_expire - tp.tv_sec < 319 _PASSWORD_WARNDAYS * SECSPERDAY) 320 (void)printf("Warning: %s's account expires on %s", 321 user, ctime(&pwd->pw_expire)); 322 } 323 #endif 324 if (ruid != 0) 325 syslog(LOG_NOTICE|LOG_AUTH, "%s to %s%s", 326 username, user, ontty()); 327 328 (void)setpriority(PRIO_PROCESS, 0, prio); 329 330 execv(shell, np); 331 err(1, "%s", shell); 332 /* NOTREACHED */ 333 } 334 335 static int 336 chshell(sh) 337 const char *sh; 338 { 339 const char *cp; 340 341 while ((cp = getusershell()) != NULL) 342 if (!strcmp(cp, sh)) 343 return (1); 344 return (0); 345 } 346 347 static char * 348 ontty() 349 { 350 char *p; 351 static char buf[MAXPATHLEN + 4]; 352 353 buf[0] = 0; 354 if ((p = ttyname(STDERR_FILENO)) != NULL) 355 (void)snprintf(buf, sizeof buf, " on %s", p); 356 return (buf); 357 } 358 359 #ifdef KERBEROS 360 static int 361 kerberos(username, user, uid) 362 char *username, *user; 363 int uid; 364 { 365 KTEXT_ST ticket; 366 AUTH_DAT authdata; 367 struct hostent *hp; 368 int kerno; 369 u_long faddr; 370 char lrealm[REALM_SZ], krbtkfile[MAXPATHLEN]; 371 char hostname[MAXHOSTNAMELEN + 1], savehost[MAXHOSTNAMELEN + 1]; 372 373 if (krb_get_lrealm(lrealm, 1) != KSUCCESS || 374 strcmp(lrealm, KRB_REALM) == 0) 375 return (1); 376 if (koktologin(username, lrealm, user) && !uid) { 377 warnx("kerberos: not in %s's ACL.", user); 378 return (1); 379 } 380 (void)snprintf(krbtkfile, sizeof krbtkfile, "%s_%s_%d", TKT_ROOT, 381 user, getuid()); 382 383 (void)setenv("KRBTKFILE", krbtkfile, 1); 384 (void)krb_set_tkt_string(krbtkfile); 385 /* 386 * Set real as well as effective ID to 0 for the moment, 387 * to make the kerberos library do the right thing. 388 */ 389 if (setuid(0) < 0) { 390 warn("setuid"); 391 return (1); 392 } 393 394 /* 395 * Little trick here -- if we are su'ing to root, 396 * we need to get a ticket for "xxx.root", where xxx represents 397 * the name of the person su'ing. Otherwise (non-root case), 398 * we need to get a ticket for "yyy.", where yyy represents 399 * the name of the person being su'd to, and the instance is null 400 * 401 * We should have a way to set the ticket lifetime, 402 * with a system default for root. 403 */ 404 kerno = krb_get_pw_in_tkt((uid == 0 ? username : user), 405 (uid == 0 ? "root" : ""), lrealm, 406 "krbtgt", lrealm, DEFAULT_TKT_LIFE, 0); 407 408 if (kerno != KSUCCESS) { 409 if (kerno == KDC_PR_UNKNOWN) { 410 warnx("kerberos: principal unknown: %s.%s@%s", 411 (uid == 0 ? username : user), 412 (uid == 0 ? "root" : ""), lrealm); 413 return (1); 414 } 415 warnx("kerberos: unable to su: %s", krb_err_txt[kerno]); 416 syslog(LOG_NOTICE|LOG_AUTH, 417 "BAD Kerberos SU: %s to %s%s: %s", 418 username, user, ontty(), krb_err_txt[kerno]); 419 return (1); 420 } 421 422 if (chown(krbtkfile, uid, -1) < 0) { 423 warn("chown"); 424 (void)unlink(krbtkfile); 425 return (1); 426 } 427 428 (void)setpriority(PRIO_PROCESS, 0, -2); 429 430 if (gethostname(hostname, sizeof(hostname)) == -1) { 431 warn("gethostname"); 432 dest_tkt(); 433 return (1); 434 } 435 hostname[sizeof(hostname) - 1] = '\0'; 436 437 (void)strncpy(savehost, krb_get_phost(hostname), sizeof(savehost)); 438 savehost[sizeof(savehost) - 1] = '\0'; 439 440 kerno = krb_mk_req(&ticket, "rcmd", savehost, lrealm, 33); 441 442 if (kerno == KDC_PR_UNKNOWN) { 443 warnx("Warning: TGT not verified."); 444 syslog(LOG_NOTICE|LOG_AUTH, 445 "%s to %s%s, TGT not verified (%s); %s.%s not registered?", 446 username, user, ontty(), krb_err_txt[kerno], 447 "rcmd", savehost); 448 } else if (kerno != KSUCCESS) { 449 warnx("Unable to use TGT: %s", krb_err_txt[kerno]); 450 syslog(LOG_NOTICE|LOG_AUTH, "failed su: %s to %s%s: %s", 451 username, user, ontty(), krb_err_txt[kerno]); 452 dest_tkt(); 453 return (1); 454 } else { 455 if (!(hp = gethostbyname(hostname))) { 456 warnx("can't get addr of %s", hostname); 457 dest_tkt(); 458 return (1); 459 } 460 memmove((char *)&faddr, (char *)hp->h_addr, sizeof(faddr)); 461 462 if ((kerno = krb_rd_req(&ticket, "rcmd", savehost, faddr, 463 &authdata, "")) != KSUCCESS) { 464 warnx("kerberos: unable to verify rcmd ticket: %s\n", 465 krb_err_txt[kerno]); 466 syslog(LOG_NOTICE|LOG_AUTH, 467 "failed su: %s to %s%s: %s", username, 468 user, ontty(), krb_err_txt[kerno]); 469 dest_tkt(); 470 return (1); 471 } 472 } 473 return (0); 474 } 475 476 static int 477 koktologin(name, realm, toname) 478 char *name, *realm, *toname; 479 { 480 AUTH_DAT *kdata; 481 AUTH_DAT kdata_st; 482 483 kdata = &kdata_st; 484 memset((char *)kdata, 0, sizeof(*kdata)); 485 (void)strncpy(kdata->pname, name, sizeof(kdata->pname) - 1); 486 (void)strncpy(kdata->pinst, 487 ((strcmp(toname, "root") == 0) ? "root" : ""), sizeof(kdata->pinst) - 1); 488 (void)strncpy(kdata->prealm, realm, sizeof(kdata->prealm) - 1); 489 return (kuserok(kdata, toname)); 490 } 491 #endif 492
Indexes created Fri Sep 26 20:09:58 GMT 2025