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