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, &registry, 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