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