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 #include "auth.h" 29 #include "ssh.h" 30 #include "log.h" 31 #include "xmalloc.h" 32 #include "buffer.h" 33 34 #ifdef _AIX 35 36 #include <errno.h> 37 #if defined(HAVE_NETDB_H) 38 # include <netdb.h> 39 #endif 40 #include <uinfo.h> 41 #include <sys/socket.h> 42 #include "port-aix.h" 43 44 # ifdef HAVE_SETAUTHDB 45 static char old_registry[REGISTRY_SIZE] = ""; 46 # endif 47 48 /* 49 * AIX has a "usrinfo" area where logname and other stuff is stored - 50 * a few applications actually use this and die if it's not set 51 * 52 * NOTE: TTY= should be set, but since no one uses it and it's hard to 53 * acquire due to privsep code. We will just drop support. 54 */ 55 void 56 aix_usrinfo(struct passwd *pw) 57 { 58 u_int i; 59 size_t len; 60 char *cp; 61 62 len = sizeof("LOGNAME= NAME= ") + (2 * strlen(pw->pw_name)); 63 cp = xmalloc(len); 64 65 i = snprintf(cp, len, "LOGNAME=%s%cNAME=%s%c", pw->pw_name, '\0', 66 pw->pw_name, '\0'); 67 if (usrinfo(SETUINFO, cp, i) == -1) 68 fatal("Couldn't set usrinfo: %s", strerror(errno)); 69 debug3("AIX/UsrInfo: set len %d", i); 70 71 xfree(cp); 72 } 73 74 # ifdef WITH_AIXAUTHENTICATE 75 /* 76 * Remove embedded newlines in string (if any). 77 * Used before logging messages returned by AIX authentication functions 78 * so the message is logged on one line. 79 */ 80 void 81 aix_remove_embedded_newlines(char *p) 82 { 83 if (p == NULL) 84 return; 85 86 for (; *p; p++) { 87 if (*p == '\n') 88 *p = ' '; 89 } 90 /* Remove trailing whitespace */ 91 if (*--p == ' ') 92 *p = '\0'; 93 } 94 95 /* 96 * Test specifically for the case where SYSTEM == NONE and AUTH1 contains 97 * anything other than NONE or SYSTEM, which indicates that the admin has 98 * configured the account for purely AUTH1-type authentication. 99 * 100 * Since authenticate() doesn't check AUTH1, and sshd can't sanely support 101 * AUTH1 itself, in such a case authenticate() will allow access without 102 * authentation, which is almost certainly not what the admin intends. 103 * 104 * (The native tools, eg login, will process the AUTH1 list in addition to 105 * the SYSTEM list by using ckuserID(), however ckuserID() and AUTH1 methods 106 * have been deprecated since AIX 4.2.x and would be very difficult for sshd 107 * to support. 108 * 109 * Returns 0 if an unsupportable combination is found, 1 otherwise. 110 */ 111 static int 112 aix_valid_authentications(const char *user) 113 { 114 char *auth1, *sys, *p; 115 int valid = 1; 116 117 if (getuserattr((char *)user, S_AUTHSYSTEM, &sys, SEC_CHAR) != 0) { 118 logit("Can't retrieve attribute SYSTEM for %s: %.100s", 119 user, strerror(errno)); 120 return 0; 121 } 122 123 debug3("AIX SYSTEM attribute %s", sys); 124 if (strcmp(sys, "NONE") != 0) 125 return 1; /* not "NONE", so is OK */ 126 127 if (getuserattr((char *)user, S_AUTH1, &auth1, SEC_LIST) != 0) { 128 logit("Can't retrieve attribute auth1 for %s: %.100s", 129 user, strerror(errno)); 130 return 0; 131 } 132 133 p = auth1; 134 /* A SEC_LIST is concatenated strings, ending with two NULs. */ 135 while (p[0] != '\0' && p[1] != '\0') { 136 debug3("AIX auth1 attribute list member %s", p); 137 if (strcmp(p, "NONE") != 0 && strcmp(p, "SYSTEM")) { 138 logit("Account %s has unsupported auth1 value '%s'", 139 user, p); 140 valid = 0; 141 } 142 p += strlen(p) + 1; 143 } 144 145 return (valid); 146 } 147 148 /* 149 * Do authentication via AIX's authenticate routine. We loop until the 150 * reenter parameter is 0, but normally authenticate is called only once. 151 * 152 * Note: this function returns 1 on success, whereas AIX's authenticate() 153 * returns 0. 154 */ 155 int 156 sys_auth_passwd(Authctxt *ctxt, const char *password) 157 { 158 char *authmsg = NULL, *msg = NULL, *name = ctxt->pw->pw_name; 159 int authsuccess = 0, expired, reenter, result; 160 161 do { 162 result = authenticate((char *)name, (char *)password, &reenter, 163 &authmsg); 164 aix_remove_embedded_newlines(authmsg); 165 debug3("AIX/authenticate result %d, authmsg %.100s", result, 166 authmsg); 167 } while (reenter); 168 169 if (!aix_valid_authentications(name)) 170 result = -1; 171 172 if (result == 0) { 173 authsuccess = 1; 174 175 /* 176 * Record successful login. We don't have a pty yet, so just 177 * label the line as "ssh" 178 */ 179 aix_setauthdb(name); 180 181 /* 182 * Check if the user's password is expired. 183 */ 184 expired = passwdexpired(name, &msg); 185 if (msg && *msg) { 186 buffer_append(ctxt->loginmsg, msg, strlen(msg)); 187 aix_remove_embedded_newlines(msg); 188 } 189 debug3("AIX/passwdexpired returned %d msg %.100s", expired, msg); 190 191 switch (expired) { 192 case 0: /* password not expired */ 193 break; 194 case 1: /* expired, password change required */ 195 ctxt->force_pwchange = 1; 196 break; 197 default: /* user can't change(2) or other error (-1) */ 198 logit("Password can't be changed for user %s: %.100s", 199 name, msg); 200 if (msg) 201 xfree(msg); 202 authsuccess = 0; 203 } 204 205 aix_restoreauthdb(); 206 } 207 208 if (authmsg != NULL) 209 xfree(authmsg); 210 211 return authsuccess; 212 } 213 214 /* 215 * Check if specified account is permitted to log in. 216 * Returns 1 if login is allowed, 0 if not allowed. 217 */ 218 int 219 sys_auth_allowed_user(struct passwd *pw, Buffer *loginmsg) 220 { 221 char *msg = NULL; 222 int result, permitted = 0; 223 struct stat st; 224 225 /* 226 * Don't perform checks for root account (PermitRootLogin controls 227 * logins via * ssh) or if running as non-root user (since 228 * loginrestrictions will always fail due to insufficient privilege). 229 */ 230 if (pw->pw_uid == 0 || geteuid() != 0) { 231 debug3("%s: not checking", __func__); 232 return 1; 233 } 234 235 result = loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &msg); 236 if (result == 0) 237 permitted = 1; 238 /* 239 * If restricted because /etc/nologin exists, the login will be denied 240 * in session.c after the nologin message is sent, so allow for now 241 * and do not append the returned message. 242 */ 243 if (result == -1 && errno == EPERM && stat(_PATH_NOLOGIN, &st) == 0) 244 permitted = 1; 245 else if (msg != NULL) 246 buffer_append(loginmsg, msg, strlen(msg)); 247 if (msg == NULL) 248 msg = xstrdup("(none)"); 249 aix_remove_embedded_newlines(msg); 250 debug3("AIX/loginrestrictions returned %d msg %.100s", result, msg); 251 252 if (!permitted) 253 logit("Login restricted for %s: %.100s", pw->pw_name, msg); 254 xfree(msg); 255 return permitted; 256 } 257 258 int 259 sys_auth_record_login(const char *user, const char *host, const char *ttynm, 260 Buffer *loginmsg) 261 { 262 char *msg = NULL; 263 int success = 0; 264 265 aix_setauthdb(user); 266 if (loginsuccess((char *)user, (char *)host, (char *)ttynm, &msg) == 0) { 267 success = 1; 268 if (msg != NULL) { 269 debug("AIX/loginsuccess: msg %s", msg); 270 buffer_append(loginmsg, msg, strlen(msg)); 271 xfree(msg); 272 } 273 } 274 aix_restoreauthdb(); 275 return (success); 276 } 277 278 # ifdef CUSTOM_FAILED_LOGIN 279 /* 280 * record_failed_login: generic "login failed" interface function 281 */ 282 void 283 record_failed_login(const char *user, const char *hostname, const char *ttyname) 284 { 285 if (geteuid() != 0) 286 return; 287 288 aix_setauthdb(user); 289 # ifdef AIX_LOGINFAILED_4ARG 290 loginfailed((char *)user, (char *)hostname, (char *)ttyname, 291 AUDIT_FAIL_AUTH); 292 # else 293 loginfailed((char *)user, (char *)hostname, (char *)ttyname); 294 # endif 295 aix_restoreauthdb(); 296 } 297 # endif /* CUSTOM_FAILED_LOGIN */ 298 299 /* 300 * If we have setauthdb, retrieve the password registry for the user's 301 * account then feed it to setauthdb. This will mean that subsequent AIX auth 302 * functions will only use the specified loadable module. If we don't have 303 * setauthdb this is a no-op. 304 */ 305 void 306 aix_setauthdb(const char *user) 307 { 308 # ifdef HAVE_SETAUTHDB 309 char *registry; 310 311 if (setuserdb(S_READ) == -1) { 312 debug3("%s: Could not open userdb to read", __func__); 313 return; 314 } 315 316 if (getuserattr((char *)user, S_REGISTRY, ®istry, SEC_CHAR) == 0) { 317 if (setauthdb(registry, old_registry) == 0) 318 debug3("AIX/setauthdb set registry '%s'", registry); 319 else 320 debug3("AIX/setauthdb set registry '%s' failed: %s", 321 registry, strerror(errno)); 322 } else 323 debug3("%s: Could not read S_REGISTRY for user: %s", __func__, 324 strerror(errno)); 325 enduserdb(); 326 # endif /* HAVE_SETAUTHDB */ 327 } 328 329 /* 330 * Restore the user's registry settings from old_registry. 331 * Note that if the first aix_setauthdb fails, setauthdb("") is still safe 332 * (it restores the system default behaviour). If we don't have setauthdb, 333 * this is a no-op. 334 */ 335 void 336 aix_restoreauthdb(void) 337 { 338 # ifdef HAVE_SETAUTHDB 339 if (setauthdb(old_registry, NULL) == 0) 340 debug3("%s: restoring old registry '%s'", __func__, 341 old_registry); 342 else 343 debug3("%s: failed to restore old registry %s", __func__, 344 old_registry); 345 # endif /* HAVE_SETAUTHDB */ 346 } 347 348 # endif /* WITH_AIXAUTHENTICATE */ 349 350 # if defined(AIX_GETNAMEINFO_HACK) && !defined(BROKEN_ADDRINFO) 351 # undef getnameinfo 352 /* 353 * For some reason, AIX's getnameinfo will refuse to resolve the all-zeros 354 * IPv6 address into its textual representation ("::"), so we wrap it 355 * with a function that will. 356 */ 357 int 358 sshaix_getnameinfo(const struct sockaddr *sa, size_t salen, char *host, 359 size_t hostlen, char *serv, size_t servlen, int flags) 360 { 361 struct sockaddr_in6 *sa6; 362 u_int32_t *a6; 363 364 if (flags & (NI_NUMERICHOST|NI_NUMERICSERV) && 365 sa->sa_family == AF_INET6) { 366 sa6 = (struct sockaddr_in6 *)sa; 367 a6 = sa6->sin6_addr.u6_addr.u6_addr32; 368 369 if (a6[0] == 0 && a6[1] == 0 && a6[2] == 0 && a6[3] == 0) { 370 strlcpy(host, "::", hostlen); 371 snprintf(serv, servlen, "%d", sa6->sin6_port); 372 return 0; 373 } 374 } 375 return getnameinfo(sa, salen, host, hostlen, serv, servlen, flags); 376 } 377 # endif /* AIX_GETNAMEINFO_HACK */ 378 379 #endif /* _AIX */ 380