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 #ifdef _AIX
30
31 #include "xmalloc.h"
32 #include "sshbuf.h"
33 #include "ssherr.h"
34 #include "sshkey.h"
35 #include "hostfile.h"
36 #include "auth.h"
37 #include "ssh.h"
38 #include "ssh_api.h"
39 #include "log.h"
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
aix_usrinfo(struct passwd * pw)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
aix_remove_embedded_newlines(char * p)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
aix_valid_authentications(const char * user)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
sys_auth_passwd(struct ssh * ssh,const char * password)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
sys_auth_allowed_user(struct passwd * pw,struct sshbuf * loginmsg)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
sys_auth_record_login(const char * user,const char * host,const char * ttynm,struct sshbuf * loginmsg)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 *
sys_auth_get_lastlogin_msg(const char * user,uid_t uid)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
record_failed_login(struct ssh * ssh,const char * user,const char * hostname,const char * ttyname)316 record_failed_login(struct ssh *ssh, const char *user, const char *hostname,
317 const char *ttyname)
318 {
319 if (geteuid() != 0)
320 return;
321
322 aix_setauthdb(user);
323 # ifdef AIX_LOGINFAILED_4ARG
324 loginfailed((char *)user, (char *)hostname, (char *)ttyname,
325 AUDIT_FAIL_AUTH);
326 # else
327 loginfailed((char *)user, (char *)hostname, (char *)ttyname);
328 # endif
329 aix_restoreauthdb();
330 }
331 # endif /* CUSTOM_FAILED_LOGIN */
332
333 /*
334 * If we have setauthdb, retrieve the password registry for the user's
335 * account then feed it to setauthdb. This will mean that subsequent AIX auth
336 * functions will only use the specified loadable module. If we don't have
337 * setauthdb this is a no-op.
338 */
339 void
aix_setauthdb(const char * user)340 aix_setauthdb(const char *user)
341 {
342 # ifdef HAVE_SETAUTHDB
343 char *registry;
344
345 if (setuserdb(S_READ) == -1) {
346 debug3("%s: Could not open userdb to read", __func__);
347 return;
348 }
349
350 if (getuserattr((char *)user, S_REGISTRY, ®istry, SEC_CHAR) == 0) {
351 if (setauthdb(registry, old_registry) == 0)
352 debug3("AIX/setauthdb set registry '%s'", registry);
353 else
354 debug3("AIX/setauthdb set registry '%s' failed: %s",
355 registry, strerror(errno));
356 } else
357 debug3("%s: Could not read S_REGISTRY for user: %s", __func__,
358 strerror(errno));
359 enduserdb();
360 # endif /* HAVE_SETAUTHDB */
361 }
362
363 /*
364 * Restore the user's registry settings from old_registry.
365 * Note that if the first aix_setauthdb fails, setauthdb("") is still safe
366 * (it restores the system default behaviour). If we don't have setauthdb,
367 * this is a no-op.
368 */
369 void
aix_restoreauthdb(void)370 aix_restoreauthdb(void)
371 {
372 # ifdef HAVE_SETAUTHDB
373 if (setauthdb(old_registry, NULL) == 0)
374 debug3("%s: restoring old registry '%s'", __func__,
375 old_registry);
376 else
377 debug3("%s: failed to restore old registry %s", __func__,
378 old_registry);
379 # endif /* HAVE_SETAUTHDB */
380 }
381
382 # endif /* WITH_AIXAUTHENTICATE */
383
384 # ifdef USE_AIX_KRB_NAME
385 /*
386 * aix_krb5_get_principal_name: returns the user's kerberos client principal
387 * name if configured, otherwise NULL. Caller must free returned string.
388 */
389 char *
aix_krb5_get_principal_name(const char * const_pw_name)390 aix_krb5_get_principal_name(const char *const_pw_name)
391 {
392 char *pw_name = (char *)const_pw_name;
393 char *authname = NULL, *authdomain = NULL, *principal = NULL;
394
395 setuserdb(S_READ);
396 if (getuserattr(pw_name, S_AUTHDOMAIN, &authdomain, SEC_CHAR) != 0)
397 debug("AIX getuserattr S_AUTHDOMAIN: %s", strerror(errno));
398 if (getuserattr(pw_name, S_AUTHNAME, &authname, SEC_CHAR) != 0)
399 debug("AIX getuserattr S_AUTHNAME: %s", strerror(errno));
400
401 if (authdomain != NULL)
402 xasprintf(&principal, "%s@%s", authname ? authname : pw_name,
403 authdomain);
404 else if (authname != NULL)
405 principal = xstrdup(authname);
406 enduserdb();
407 return principal;
408 }
409 # endif /* USE_AIX_KRB_NAME */
410
411 # if defined(AIX_GETNAMEINFO_HACK) && !defined(BROKEN_ADDRINFO)
412 # undef getnameinfo
413 /*
414 * For some reason, AIX's getnameinfo will refuse to resolve the all-zeros
415 * IPv6 address into its textual representation ("::"), so we wrap it
416 * with a function that will.
417 */
418 int
sshaix_getnameinfo(const struct sockaddr * sa,size_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)419 sshaix_getnameinfo(const struct sockaddr *sa, size_t salen, char *host,
420 size_t hostlen, char *serv, size_t servlen, int flags)
421 {
422 struct sockaddr_in6 *sa6;
423 u_int32_t *a6;
424
425 if (flags & (NI_NUMERICHOST|NI_NUMERICSERV) &&
426 sa->sa_family == AF_INET6) {
427 sa6 = (struct sockaddr_in6 *)sa;
428 a6 = sa6->sin6_addr.u6_addr.u6_addr32;
429
430 if (a6[0] == 0 && a6[1] == 0 && a6[2] == 0 && a6[3] == 0) {
431 strlcpy(host, "::", hostlen);
432 snprintf(serv, servlen, "%d", sa6->sin6_port);
433 return 0;
434 }
435 }
436 return getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
437 }
438 # endif /* AIX_GETNAMEINFO_HACK */
439
440 # if defined(USE_GETGRSET)
441 # include <stdlib.h>
442 int
getgrouplist(const char * user,gid_t pgid,gid_t * groups,int * grpcnt)443 getgrouplist(const char *user, gid_t pgid, gid_t *groups, int *grpcnt)
444 {
445 char *cp, *grplist, *grp;
446 gid_t gid;
447 int ret = 0, ngroups = 0, maxgroups;
448 long long ll;
449
450 maxgroups = *grpcnt;
451
452 if ((cp = grplist = getgrset(user)) == NULL)
453 return -1;
454
455 /* handle zero-length case */
456 if (maxgroups <= 0) {
457 *grpcnt = 0;
458 return -1;
459 }
460
461 /* copy primary group */
462 groups[ngroups++] = pgid;
463
464 /* copy each entry from getgrset into group list */
465 while ((grp = strsep(&grplist, ",")) != NULL) {
466 ll = strtoll(grp, NULL, 10);
467 if (ngroups >= maxgroups || ll < 0 || ll > UID_MAX) {
468 ret = -1;
469 goto out;
470 }
471 gid = (gid_t)ll;
472 if (gid == pgid)
473 continue; /* we have already added primary gid */
474 groups[ngroups++] = gid;
475 }
476 out:
477 free(cp);
478 *grpcnt = ngroups;
479 return ret;
480 }
481 # endif /* USE_GETGRSET */
482
483 #endif /* _AIX */
484