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
60static char *lastlogin_msg = NULL;
61
62# ifdef HAVE_SETAUTHDB
63static 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 */
73void
74aix_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 */
98void
99aix_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 */
129static int
130aix_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 */
173int
174sys_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 */
234int
235sys_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
274int
275sys_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
294char *
295sys_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 */
307void
308record_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 */
330void
331aix_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 */
360void
361aix_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 */
380char *
381aix_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 */
407int
408sshaix_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>
431int
432getgrouplist(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	}
465out:
466	free(cp);
467	*grpcnt = ngroups;
468	return ret;
469}
470# endif	/* USE_GETGRSET */
471
472#endif /* _AIX */
473