1 /* 2 * 3 * Copyright (c) 2001 Gert Doering. All rights reserved. 4 * Copyright (c) 2003,2004,2005,2006 Darren Tucker. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 */ 27 #include "includes.h" 28 29 #include "xmalloc.h" 30 #include "sshbuf.h" 31 #include "ssherr.h" 32 #include "sshkey.h" 33 #include "hostfile.h" 34 #include "auth.h" 35 #include "ssh.h" 36 #include "ssh_api.h" 37 #include "log.h" 38 39 #ifdef _AIX 40 41 #include <errno.h> 42 #if defined(HAVE_NETDB_H) 43 # include <netdb.h> 44 #endif 45 #include <uinfo.h> 46 #include <stdarg.h> 47 #include <string.h> 48 #include <unistd.h> 49 #include <sys/socket.h> 50 51 #ifdef WITH_AIXAUTHENTICATE 52 # include <login.h> 53 # include <userpw.h> 54 # if defined(HAVE_SYS_AUDIT_H) && defined(AIX_LOGINFAILED_4ARG) 55 # include <sys/audit.h> 56 # endif 57 # include <usersec.h> 58 #endif 59 60 #include "port-aix.h" 61 62 static char *lastlogin_msg = NULL; 63 64 # ifdef HAVE_SETAUTHDB 65 static char old_registry[REGISTRY_SIZE] = ""; 66 # endif 67 68 /* 69 * AIX has a "usrinfo" area where logname and other stuff is stored - 70 * a few applications actually use this and die if it's not set 71 * 72 * NOTE: TTY= should be set, but since no one uses it and it's hard to 73 * acquire due to privsep code. We will just drop support. 74 */ 75 void 76 aix_usrinfo(struct passwd *pw) 77 { 78 u_int i; 79 size_t len; 80 char *cp; 81 82 len = sizeof("LOGNAME= NAME= ") + (2 * strlen(pw->pw_name)); 83 cp = xmalloc(len); 84 85 i = snprintf(cp, len, "LOGNAME=%s%cNAME=%s%c", pw->pw_name, '\0', 86 pw->pw_name, '\0'); 87 if (usrinfo(SETUINFO, cp, i) == -1) 88 fatal("Couldn't set usrinfo: %s", strerror(errno)); 89 debug3("AIX/UsrInfo: set len %d", i); 90 91 free(cp); 92 } 93 94 # ifdef WITH_AIXAUTHENTICATE 95 /* 96 * Remove embedded newlines in string (if any). 97 * Used before logging messages returned by AIX authentication functions 98 * so the message is logged on one line. 99 */ 100 void 101 aix_remove_embedded_newlines(char *p) 102 { 103 if (p == NULL) 104 return; 105 106 for (; *p; p++) { 107 if (*p == '\n') 108 *p = ' '; 109 } 110 /* Remove trailing whitespace */ 111 if (*--p == ' ') 112 *p = '\0'; 113 } 114 115 /* 116 * Test specifically for the case where SYSTEM == NONE and AUTH1 contains 117 * anything other than NONE or SYSTEM, which indicates that the admin has 118 * configured the account for purely AUTH1-type authentication. 119 * 120 * Since authenticate() doesn't check AUTH1, and sshd can't sanely support 121 * AUTH1 itself, in such a case authenticate() will allow access without 122 * authentation, which is almost certainly not what the admin intends. 123 * 124 * (The native tools, eg login, will process the AUTH1 list in addition to 125 * the SYSTEM list by using ckuserID(), however ckuserID() and AUTH1 methods 126 * have been deprecated since AIX 4.2.x and would be very difficult for sshd 127 * to support. 128 * 129 * Returns 0 if an unsupportable combination is found, 1 otherwise. 130 */ 131 static int 132 aix_valid_authentications(const char *user) 133 { 134 char *auth1, *sys, *p; 135 int valid = 1; 136 137 if (getuserattr((char *)user, S_AUTHSYSTEM, &sys, SEC_CHAR) != 0) { 138 logit("Can't retrieve attribute SYSTEM for %s: %.100s", 139 user, strerror(errno)); 140 return 0; 141 } 142 143 debug3("AIX SYSTEM attribute %s", sys); 144 if (strcmp(sys, "NONE") != 0) 145 return 1; /* not "NONE", so is OK */ 146 147 if (getuserattr((char *)user, S_AUTH1, &auth1, SEC_LIST) != 0) { 148 logit("Can't retrieve attribute auth1 for %s: %.100s", 149 user, strerror(errno)); 150 return 0; 151 } 152 153 p = auth1; 154 /* A SEC_LIST is concatenated strings, ending with two NULs. */ 155 while (p[0] != '\0' && p[1] != '\0') { 156 debug3("AIX auth1 attribute list member %s", p); 157 if (strcmp(p, "NONE") != 0 && strcmp(p, "SYSTEM")) { 158 logit("Account %s has unsupported auth1 value '%s'", 159 user, p); 160 valid = 0; 161 } 162 p += strlen(p) + 1; 163 } 164 165 return (valid); 166 } 167 168 /* 169 * Do authentication via AIX's authenticate routine. We loop until the 170 * reenter parameter is 0, but normally authenticate is called only once. 171 * 172 * Note: this function returns 1 on success, whereas AIX's authenticate() 173 * returns 0. 174 */ 175 int 176 sys_auth_passwd(struct ssh *ssh, const char *password) 177 { 178 Authctxt *ctxt = ssh->authctxt; 179 char *authmsg = NULL, *msg = NULL, *name = ctxt->pw->pw_name; 180 int r, authsuccess = 0, expired, reenter, result; 181 182 do { 183 result = authenticate((char *)name, (char *)password, &reenter, 184 &authmsg); 185 aix_remove_embedded_newlines(authmsg); 186 debug3("AIX/authenticate result %d, authmsg %.100s", result, 187 authmsg); 188 } while (reenter); 189 190 if (!aix_valid_authentications(name)) 191 result = -1; 192 193 if (result == 0) { 194 authsuccess = 1; 195 196 /* 197 * Record successful login. We don't have a pty yet, so just 198 * label the line as "ssh" 199 */ 200 aix_setauthdb(name); 201 202 /* 203 * Check if the user's password is expired. 204 */ 205 expired = passwdexpired(name, &msg); 206 if (msg && *msg) { 207 if ((r = sshbuf_put(ctxt->loginmsg, 208 msg, strlen(msg))) != 0) 209 fatal("%s: buffer error: %s", 210 __func__, ssh_err(r)); 211 aix_remove_embedded_newlines(msg); 212 } 213 debug3("AIX/passwdexpired returned %d msg %.100s", expired, msg); 214 215 switch (expired) { 216 case 0: /* password not expired */ 217 break; 218 case 1: /* expired, password change required */ 219 ctxt->force_pwchange = 1; 220 break; 221 default: /* user can't change(2) or other error (-1) */ 222 logit("Password can't be changed for user %s: %.100s", 223 name, msg); 224 free(msg); 225 authsuccess = 0; 226 } 227 228 aix_restoreauthdb(); 229 } 230 231 free(authmsg); 232 233 return authsuccess; 234 } 235 236 /* 237 * Check if specified account is permitted to log in. 238 * Returns 1 if login is allowed, 0 if not allowed. 239 */ 240 int 241 sys_auth_allowed_user(struct passwd *pw, struct sshbuf *loginmsg) 242 { 243 char *msg = NULL; 244 int r, result, permitted = 0; 245 struct stat st; 246 247 /* 248 * Don't perform checks for root account (PermitRootLogin controls 249 * logins via ssh) or if running as non-root user (since 250 * loginrestrictions will always fail due to insufficient privilege). 251 */ 252 if (pw->pw_uid == 0 || geteuid() != 0) { 253 debug3("%s: not checking", __func__); 254 return 1; 255 } 256 257 result = loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &msg); 258 if (result == 0) 259 permitted = 1; 260 /* 261 * If restricted because /etc/nologin exists, the login will be denied 262 * in session.c after the nologin message is sent, so allow for now 263 * and do not append the returned message. 264 */ 265 if (result == -1 && errno == EPERM && stat(_PATH_NOLOGIN, &st) == 0) 266 permitted = 1; 267 else if (msg != NULL) { 268 if ((r = sshbuf_put(loginmsg, msg, strlen(msg))) != 0) 269 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 270 } 271 if (msg == NULL) 272 msg = xstrdup("(none)"); 273 aix_remove_embedded_newlines(msg); 274 debug3("AIX/loginrestrictions returned %d msg %.100s", result, msg); 275 276 if (!permitted) 277 logit("Login restricted for %s: %.100s", pw->pw_name, msg); 278 free(msg); 279 return permitted; 280 } 281 282 int 283 sys_auth_record_login(const char *user, const char *host, const char *ttynm, 284 struct sshbuf *loginmsg) 285 { 286 char *msg = NULL; 287 int success = 0; 288 289 aix_setauthdb(user); 290 if (loginsuccess((char *)user, (char *)host, (char *)ttynm, &msg) == 0) { 291 success = 1; 292 if (msg != NULL) { 293 debug("AIX/loginsuccess: msg %s", msg); 294 if (lastlogin_msg == NULL) 295 lastlogin_msg = msg; 296 } 297 } 298 aix_restoreauthdb(); 299 return (success); 300 } 301 302 char * 303 sys_auth_get_lastlogin_msg(const char *user, uid_t uid) 304 { 305 char *msg = lastlogin_msg; 306 307 lastlogin_msg = NULL; 308 return msg; 309 } 310 311 # ifdef CUSTOM_FAILED_LOGIN 312 /* 313 * record_failed_login: generic "login failed" interface function 314 */ 315 void 316 record_failed_login(const char *user, const char *hostname, const char *ttyname) 317 { 318 if (geteuid() != 0) 319 return; 320 321 aix_setauthdb(user); 322 # ifdef AIX_LOGINFAILED_4ARG 323 loginfailed((char *)user, (char *)hostname, (char *)ttyname, 324 AUDIT_FAIL_AUTH); 325 # else 326 loginfailed((char *)user, (char *)hostname, (char *)ttyname); 327 # endif 328 aix_restoreauthdb(); 329 } 330 # endif /* CUSTOM_FAILED_LOGIN */ 331 332 /* 333 * If we have setauthdb, retrieve the password registry for the user's 334 * account then feed it to setauthdb. This will mean that subsequent AIX auth 335 * functions will only use the specified loadable module. If we don't have 336 * setauthdb this is a no-op. 337 */ 338 void 339 aix_setauthdb(const char *user) 340 { 341 # ifdef HAVE_SETAUTHDB 342 char *registry; 343 344 if (setuserdb(S_READ) == -1) { 345 debug3("%s: Could not open userdb to read", __func__); 346 return; 347 } 348 349 if (getuserattr((char *)user, S_REGISTRY, ®istry, SEC_CHAR) == 0) { 350 if (setauthdb(registry, old_registry) == 0) 351 debug3("AIX/setauthdb set registry '%s'", registry); 352 else 353 debug3("AIX/setauthdb set registry '%s' failed: %s", 354 registry, strerror(errno)); 355 } else 356 debug3("%s: Could not read S_REGISTRY for user: %s", __func__, 357 strerror(errno)); 358 enduserdb(); 359 # endif /* HAVE_SETAUTHDB */ 360 } 361 362 /* 363 * Restore the user's registry settings from old_registry. 364 * Note that if the first aix_setauthdb fails, setauthdb("") is still safe 365 * (it restores the system default behaviour). If we don't have setauthdb, 366 * this is a no-op. 367 */ 368 void 369 aix_restoreauthdb(void) 370 { 371 # ifdef HAVE_SETAUTHDB 372 if (setauthdb(old_registry, NULL) == 0) 373 debug3("%s: restoring old registry '%s'", __func__, 374 old_registry); 375 else 376 debug3("%s: failed to restore old registry %s", __func__, 377 old_registry); 378 # endif /* HAVE_SETAUTHDB */ 379 } 380 381 # endif /* WITH_AIXAUTHENTICATE */ 382 383 # ifdef USE_AIX_KRB_NAME 384 /* 385 * aix_krb5_get_principal_name: returns the user's kerberos client principal name if 386 * configured, otherwise NULL. Caller must free returned string. 387 */ 388 char * 389 aix_krb5_get_principal_name(char *pw_name) 390 { 391 char *authname = NULL, *authdomain = NULL, *principal = NULL; 392 393 setuserdb(S_READ); 394 if (getuserattr(pw_name, S_AUTHDOMAIN, &authdomain, SEC_CHAR) != 0) 395 debug("AIX getuserattr S_AUTHDOMAIN: %s", strerror(errno)); 396 if (getuserattr(pw_name, S_AUTHNAME, &authname, SEC_CHAR) != 0) 397 debug("AIX getuserattr S_AUTHNAME: %s", strerror(errno)); 398 399 if (authdomain != NULL) 400 xasprintf(&principal, "%s@%s", authname ? authname : pw_name, authdomain); 401 else if (authname != NULL) 402 principal = xstrdup(authname); 403 enduserdb(); 404 return principal; 405 } 406 # endif /* USE_AIX_KRB_NAME */ 407 408 # if defined(AIX_GETNAMEINFO_HACK) && !defined(BROKEN_ADDRINFO) 409 # undef getnameinfo 410 /* 411 * For some reason, AIX's getnameinfo will refuse to resolve the all-zeros 412 * IPv6 address into its textual representation ("::"), so we wrap it 413 * with a function that will. 414 */ 415 int 416 sshaix_getnameinfo(const struct sockaddr *sa, size_t salen, char *host, 417 size_t hostlen, char *serv, size_t servlen, int flags) 418 { 419 struct sockaddr_in6 *sa6; 420 u_int32_t *a6; 421 422 if (flags & (NI_NUMERICHOST|NI_NUMERICSERV) && 423 sa->sa_family == AF_INET6) { 424 sa6 = (struct sockaddr_in6 *)sa; 425 a6 = sa6->sin6_addr.u6_addr.u6_addr32; 426 427 if (a6[0] == 0 && a6[1] == 0 && a6[2] == 0 && a6[3] == 0) { 428 strlcpy(host, "::", hostlen); 429 snprintf(serv, servlen, "%d", sa6->sin6_port); 430 return 0; 431 } 432 } 433 return getnameinfo(sa, salen, host, hostlen, serv, servlen, flags); 434 } 435 # endif /* AIX_GETNAMEINFO_HACK */ 436 437 # if defined(USE_GETGRSET) 438 # include <stdlib.h> 439 int 440 getgrouplist(const char *user, gid_t pgid, gid_t *groups, int *grpcnt) 441 { 442 char *cp, *grplist, *grp; 443 gid_t gid; 444 int ret = 0, ngroups = 0, maxgroups; 445 long l; 446 447 maxgroups = *grpcnt; 448 449 if ((cp = grplist = getgrset(user)) == NULL) 450 return -1; 451 452 /* handle zero-length case */ 453 if (maxgroups <= 0) { 454 *grpcnt = 0; 455 return -1; 456 } 457 458 /* copy primary group */ 459 groups[ngroups++] = pgid; 460 461 /* copy each entry from getgrset into group list */ 462 while ((grp = strsep(&grplist, ",")) != NULL) { 463 l = strtol(grp, NULL, 10); 464 if (ngroups >= maxgroups || l == LONG_MIN || l == LONG_MAX) { 465 ret = -1; 466 goto out; 467 } 468 gid = (gid_t)l; 469 if (gid == pgid) 470 continue; /* we have already added primary gid */ 471 groups[ngroups++] = gid; 472 } 473 out: 474 free(cp); 475 *grpcnt = ngroups; 476 return ret; 477 } 478 # endif /* USE_GETGRSET */ 479 480 #endif /* _AIX */ 481