1 /* 2 * 3 * Copyright (c) 2001 Gert Doering. All rights reserved. 4 * Copyright (c) 2003,2004,2005 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 # ifdef HAVE_SETAUTHDB 61 static char old_registry[REGISTRY_SIZE] = ""; 62 # endif 63 64 /* 65 * AIX has a "usrinfo" area where logname and other stuff is stored - 66 * a few applications actually use this and die if it's not set 67 * 68 * NOTE: TTY= should be set, but since no one uses it and it's hard to 69 * acquire due to privsep code. We will just drop support. 70 */ 71 void 72 aix_usrinfo(struct passwd *pw) 73 { 74 u_int i; 75 size_t len; 76 char *cp; 77 78 len = sizeof("LOGNAME= NAME= ") + (2 * strlen(pw->pw_name)); 79 cp = xmalloc(len); 80 81 i = snprintf(cp, len, "LOGNAME=%s%cNAME=%s%c", pw->pw_name, '\0', 82 pw->pw_name, '\0'); 83 if (usrinfo(SETUINFO, cp, i) == -1) 84 fatal("Couldn't set usrinfo: %s", strerror(errno)); 85 debug3("AIX/UsrInfo: set len %d", i); 86 87 xfree(cp); 88 } 89 90 # ifdef WITH_AIXAUTHENTICATE 91 /* 92 * Remove embedded newlines in string (if any). 93 * Used before logging messages returned by AIX authentication functions 94 * so the message is logged on one line. 95 */ 96 void 97 aix_remove_embedded_newlines(char *p) 98 { 99 if (p == NULL) 100 return; 101 102 for (; *p; p++) { 103 if (*p == '\n') 104 *p = ' '; 105 } 106 /* Remove trailing whitespace */ 107 if (*--p == ' ') 108 *p = '\0'; 109 } 110 111 /* 112 * Test specifically for the case where SYSTEM == NONE and AUTH1 contains 113 * anything other than NONE or SYSTEM, which indicates that the admin has 114 * configured the account for purely AUTH1-type authentication. 115 * 116 * Since authenticate() doesn't check AUTH1, and sshd can't sanely support 117 * AUTH1 itself, in such a case authenticate() will allow access without 118 * authentation, which is almost certainly not what the admin intends. 119 * 120 * (The native tools, eg login, will process the AUTH1 list in addition to 121 * the SYSTEM list by using ckuserID(), however ckuserID() and AUTH1 methods 122 * have been deprecated since AIX 4.2.x and would be very difficult for sshd 123 * to support. 124 * 125 * Returns 0 if an unsupportable combination is found, 1 otherwise. 126 */ 127 static int 128 aix_valid_authentications(const char *user) 129 { 130 char *auth1, *sys, *p; 131 int valid = 1; 132 133 if (getuserattr((char *)user, S_AUTHSYSTEM, &sys, SEC_CHAR) != 0) { 134 logit("Can't retrieve attribute SYSTEM for %s: %.100s", 135 user, strerror(errno)); 136 return 0; 137 } 138 139 debug3("AIX SYSTEM attribute %s", sys); 140 if (strcmp(sys, "NONE") != 0) 141 return 1; /* not "NONE", so is OK */ 142 143 if (getuserattr((char *)user, S_AUTH1, &auth1, SEC_LIST) != 0) { 144 logit("Can't retrieve attribute auth1 for %s: %.100s", 145 user, strerror(errno)); 146 return 0; 147 } 148 149 p = auth1; 150 /* A SEC_LIST is concatenated strings, ending with two NULs. */ 151 while (p[0] != '\0' && p[1] != '\0') { 152 debug3("AIX auth1 attribute list member %s", p); 153 if (strcmp(p, "NONE") != 0 && strcmp(p, "SYSTEM")) { 154 logit("Account %s has unsupported auth1 value '%s'", 155 user, p); 156 valid = 0; 157 } 158 p += strlen(p) + 1; 159 } 160 161 return (valid); 162 } 163 164 /* 165 * Do authentication via AIX's authenticate routine. We loop until the 166 * reenter parameter is 0, but normally authenticate is called only once. 167 * 168 * Note: this function returns 1 on success, whereas AIX's authenticate() 169 * returns 0. 170 */ 171 int 172 sys_auth_passwd(Authctxt *ctxt, const char *password) 173 { 174 char *authmsg = NULL, *msg = NULL, *name = ctxt->pw->pw_name; 175 int authsuccess = 0, expired, reenter, result; 176 177 do { 178 result = authenticate((char *)name, (char *)password, &reenter, 179 &authmsg); 180 aix_remove_embedded_newlines(authmsg); 181 debug3("AIX/authenticate result %d, authmsg %.100s", result, 182 authmsg); 183 } while (reenter); 184 185 if (!aix_valid_authentications(name)) 186 result = -1; 187 188 if (result == 0) { 189 authsuccess = 1; 190 191 /* 192 * Record successful login. We don't have a pty yet, so just 193 * label the line as "ssh" 194 */ 195 aix_setauthdb(name); 196 197 /* 198 * Check if the user's password is expired. 199 */ 200 expired = passwdexpired(name, &msg); 201 if (msg && *msg) { 202 buffer_append(ctxt->loginmsg, msg, strlen(msg)); 203 aix_remove_embedded_newlines(msg); 204 } 205 debug3("AIX/passwdexpired returned %d msg %.100s", expired, msg); 206 207 switch (expired) { 208 case 0: /* password not expired */ 209 break; 210 case 1: /* expired, password change required */ 211 ctxt->force_pwchange = 1; 212 break; 213 default: /* user can't change(2) or other error (-1) */ 214 logit("Password can't be changed for user %s: %.100s", 215 name, msg); 216 if (msg) 217 xfree(msg); 218 authsuccess = 0; 219 } 220 221 aix_restoreauthdb(); 222 } 223 224 if (authmsg != NULL) 225 xfree(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 xfree(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 static int msg_done = 0; 280 int success = 0; 281 282 aix_setauthdb(user); 283 if (loginsuccess((char *)user, (char *)host, (char *)ttynm, &msg) == 0) { 284 success = 1; 285 if (msg != NULL && loginmsg != NULL && !msg_done) { 286 debug("AIX/loginsuccess: msg %s", msg); 287 buffer_append(loginmsg, msg, strlen(msg)); 288 xfree(msg); 289 msg_done = 1; 290 } 291 } 292 aix_restoreauthdb(); 293 return (success); 294 } 295 296 # ifdef CUSTOM_FAILED_LOGIN 297 /* 298 * record_failed_login: generic "login failed" interface function 299 */ 300 void 301 record_failed_login(const char *user, const char *hostname, const char *ttyname) 302 { 303 if (geteuid() != 0) 304 return; 305 306 aix_setauthdb(user); 307 # ifdef AIX_LOGINFAILED_4ARG 308 loginfailed((char *)user, (char *)hostname, (char *)ttyname, 309 AUDIT_FAIL_AUTH); 310 # else 311 loginfailed((char *)user, (char *)hostname, (char *)ttyname); 312 # endif 313 aix_restoreauthdb(); 314 } 315 # endif /* CUSTOM_FAILED_LOGIN */ 316 317 /* 318 * If we have setauthdb, retrieve the password registry for the user's 319 * account then feed it to setauthdb. This will mean that subsequent AIX auth 320 * functions will only use the specified loadable module. If we don't have 321 * setauthdb this is a no-op. 322 */ 323 void 324 aix_setauthdb(const char *user) 325 { 326 # ifdef HAVE_SETAUTHDB 327 char *registry; 328 329 if (setuserdb(S_READ) == -1) { 330 debug3("%s: Could not open userdb to read", __func__); 331 return; 332 } 333 334 if (getuserattr((char *)user, S_REGISTRY, ®istry, SEC_CHAR) == 0) { 335 if (setauthdb(registry, old_registry) == 0) 336 debug3("AIX/setauthdb set registry '%s'", registry); 337 else 338 debug3("AIX/setauthdb set registry '%s' failed: %s", 339 registry, strerror(errno)); 340 } else 341 debug3("%s: Could not read S_REGISTRY for user: %s", __func__, 342 strerror(errno)); 343 enduserdb(); 344 # endif /* HAVE_SETAUTHDB */ 345 } 346 347 /* 348 * Restore the user's registry settings from old_registry. 349 * Note that if the first aix_setauthdb fails, setauthdb("") is still safe 350 * (it restores the system default behaviour). If we don't have setauthdb, 351 * this is a no-op. 352 */ 353 void 354 aix_restoreauthdb(void) 355 { 356 # ifdef HAVE_SETAUTHDB 357 if (setauthdb(old_registry, NULL) == 0) 358 debug3("%s: restoring old registry '%s'", __func__, 359 old_registry); 360 else 361 debug3("%s: failed to restore old registry %s", __func__, 362 old_registry); 363 # endif /* HAVE_SETAUTHDB */ 364 } 365 366 # endif /* WITH_AIXAUTHENTICATE */ 367 368 # if defined(AIX_GETNAMEINFO_HACK) && !defined(BROKEN_ADDRINFO) 369 # undef getnameinfo 370 /* 371 * For some reason, AIX's getnameinfo will refuse to resolve the all-zeros 372 * IPv6 address into its textual representation ("::"), so we wrap it 373 * with a function that will. 374 */ 375 int 376 sshaix_getnameinfo(const struct sockaddr *sa, size_t salen, char *host, 377 size_t hostlen, char *serv, size_t servlen, int flags) 378 { 379 struct sockaddr_in6 *sa6; 380 u_int32_t *a6; 381 382 if (flags & (NI_NUMERICHOST|NI_NUMERICSERV) && 383 sa->sa_family == AF_INET6) { 384 sa6 = (struct sockaddr_in6 *)sa; 385 a6 = sa6->sin6_addr.u6_addr.u6_addr32; 386 387 if (a6[0] == 0 && a6[1] == 0 && a6[2] == 0 && a6[3] == 0) { 388 strlcpy(host, "::", hostlen); 389 snprintf(serv, servlen, "%d", sa6->sin6_port); 390 return 0; 391 } 392 } 393 return getnameinfo(sa, salen, host, hostlen, serv, servlen, flags); 394 } 395 # endif /* AIX_GETNAMEINFO_HACK */ 396 397 #endif /* _AIX */ 398