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
62static char *lastlogin_msg = NULL;
63
64# ifdef HAVE_SETAUTHDB
65static 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 */
75void
76aix_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 */
100void
101aix_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 */
131static int
132aix_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 */
175int
176sys_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 */
240int
241sys_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
282int
283sys_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
302char *
303sys_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 */
315void
316record_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 */
339void
340aix_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, &registry, 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 */
369void
370aix_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 */
389char *
390aix_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 */
418int
419sshaix_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>
442int
443getgrouplist(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	}
476out:
477	free(cp);
478	*grpcnt = ngroups;
479	return ret;
480}
481# endif	/* USE_GETGRSET */
482
483#endif /* _AIX */
484