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
aix_usrinfo(struct passwd * pw)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
aix_remove_embedded_newlines(char * p)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
aix_valid_authentications(const char * user)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
sys_auth_passwd(Authctxt * ctxt,const char * password)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
sys_auth_allowed_user(struct passwd * pw,Buffer * loginmsg)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
sys_auth_record_login(const char * user,const char * host,const char * ttynm,Buffer * loginmsg)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 *
sys_auth_get_lastlogin_msg(const char * user,uid_t uid)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
record_failed_login(const char * user,const char * hostname,const char * ttyname)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
aix_setauthdb(const char * user)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
aix_restoreauthdb(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 *
aix_krb5_get_principal_name(char * pw_name)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
sshaix_getnameinfo(const struct sockaddr * sa,size_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)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
getgrouplist(const char * user,gid_t pgid,gid_t * groups,int * grpcnt)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