xref: /freebsd/contrib/openpam/lib/libpam/openpam_dispatch.c (revision 734e82fe33aa764367791a7d603b383996c6b40b)
1 /*-
2  * Copyright (c) 2002-2003 Networks Associates Technology, Inc.
3  * Copyright (c) 2004-2017 Dag-Erling Smørgrav
4  * All rights reserved.
5  *
6  * This software was developed for the FreeBSD Project by ThinkSec AS and
7  * Network Associates Laboratories, the Security Research Division of
8  * Network Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
9  * ("CBOSS"), as part of the DARPA CHATS research program.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. The name of the author may not be used to endorse or promote
20  *    products derived from this software without specific prior written
21  *    permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #ifdef HAVE_CONFIG_H
37 # include "config.h"
38 #endif
39 
40 #include <sys/param.h>
41 
42 #include <stdint.h>
43 
44 #include <security/pam_appl.h>
45 
46 #include "openpam_impl.h"
47 
48 #if !defined(OPENPAM_RELAX_CHECKS)
49 static void openpam_check_error_code(int, int);
50 #else
51 #define openpam_check_error_code(a, b)
52 #endif /* !defined(OPENPAM_RELAX_CHECKS) */
53 
54 /*
55  * OpenPAM internal
56  *
57  * Execute a module chain
58  */
59 
60 int
61 openpam_dispatch(pam_handle_t *pamh,
62 	int primitive,
63 	int flags)
64 {
65 	pam_chain_t *chain;
66 	int err, fail, nsuccess, r;
67 	int debug;
68 
69 	ENTER();
70 
71 	/* prevent recursion */
72 	if (pamh->current != NULL) {
73 		openpam_log(PAM_LOG_ERROR,
74 		    "%s() called while %s::%s() is in progress",
75 		    pam_func_name[primitive],
76 		    pamh->current->module->path,
77 		    pam_sm_func_name[pamh->primitive]);
78 		RETURNC(PAM_ABORT);
79 	}
80 
81 	/* pick a chain */
82 	switch (primitive) {
83 	case PAM_SM_AUTHENTICATE:
84 	case PAM_SM_SETCRED:
85 		chain = pamh->chains[PAM_AUTH];
86 		break;
87 	case PAM_SM_ACCT_MGMT:
88 		chain = pamh->chains[PAM_ACCOUNT];
89 		break;
90 	case PAM_SM_OPEN_SESSION:
91 	case PAM_SM_CLOSE_SESSION:
92 		chain = pamh->chains[PAM_SESSION];
93 		break;
94 	case PAM_SM_CHAUTHTOK:
95 		chain = pamh->chains[PAM_PASSWORD];
96 		break;
97 	default:
98 		RETURNC(PAM_SYSTEM_ERR);
99 	}
100 
101 	/* execute */
102 	err = PAM_SUCCESS;
103 	fail = nsuccess = 0;
104 	for (; chain != NULL; chain = chain->next) {
105 		if (chain->module->func[primitive] == NULL) {
106 			openpam_log(PAM_LOG_ERROR, "%s: no %s()",
107 			    chain->module->path, pam_sm_func_name[primitive]);
108 			r = PAM_SYMBOL_ERR;
109 		} else {
110 			pamh->primitive = primitive;
111 			pamh->current = chain;
112 			debug = (openpam_get_option(pamh, "debug") != NULL);
113 			if (debug)
114 				++openpam_debug;
115 			openpam_log(PAM_LOG_LIBDEBUG, "calling %s() in %s",
116 			    pam_sm_func_name[primitive], chain->module->path);
117 			r = (chain->module->func[primitive])(pamh, flags,
118 			    chain->optc, (const char **)(intptr_t)chain->optv);
119 			pamh->current = NULL;
120 			openpam_log(PAM_LOG_LIBDEBUG, "%s: %s(): %s",
121 			    chain->module->path, pam_sm_func_name[primitive],
122 			    pam_strerror(pamh, r));
123 			if (debug)
124 				--openpam_debug;
125 		}
126 
127 		if (r == PAM_IGNORE)
128 			continue;
129 		if (r == PAM_SUCCESS) {
130 			++nsuccess;
131 			/*
132 			 * For pam_setcred() and pam_chauthtok() with the
133 			 * PAM_PRELIM_CHECK flag, treat "sufficient" as
134 			 * "optional".
135 			 */
136 			if ((chain->flag == PAM_SUFFICIENT ||
137 			    chain->flag == PAM_BINDING) && !fail &&
138 			    primitive != PAM_SM_SETCRED &&
139 			    !(primitive == PAM_SM_CHAUTHTOK &&
140 				(flags & PAM_PRELIM_CHECK)))
141 				break;
142 			continue;
143 		}
144 
145 		openpam_check_error_code(primitive, r);
146 
147 		/*
148 		 * Record the return code from the first module to
149 		 * fail.  If a required module fails, record the
150 		 * return code from the first required module to fail.
151 		 */
152 		if (err == PAM_SUCCESS)
153 			err = r;
154 		if ((chain->flag == PAM_REQUIRED ||
155 		    chain->flag == PAM_BINDING) && !fail) {
156 			openpam_log(PAM_LOG_LIBDEBUG, "required module failed");
157 			fail = 1;
158 			err = r;
159 		}
160 
161 		/*
162 		 * If a requisite module fails, terminate the chain
163 		 * immediately.
164 		 */
165 		if (chain->flag == PAM_REQUISITE) {
166 			openpam_log(PAM_LOG_LIBDEBUG, "requisite module failed");
167 			fail = 1;
168 			break;
169 		}
170 	}
171 
172 	if (!fail && err != PAM_NEW_AUTHTOK_REQD)
173 		err = PAM_SUCCESS;
174 
175 	/*
176 	 * Require the chain to be non-empty, and at least one module
177 	 * in the chain to be successful, so that we don't fail open.
178 	 */
179 	if (err == PAM_SUCCESS && nsuccess < 1) {
180 		openpam_log(PAM_LOG_ERROR,
181 		    "all modules were unsuccessful for %s()",
182 		    pam_sm_func_name[primitive]);
183 		err = PAM_SYSTEM_ERR;
184 	}
185 
186 	RETURNC(err);
187 }
188 
189 #if !defined(OPENPAM_RELAX_CHECKS)
190 static void
191 openpam_check_error_code(int primitive, int r)
192 {
193 	/* common error codes */
194 	if (r == PAM_SUCCESS ||
195 	    r == PAM_SYSTEM_ERR ||
196 	    r == PAM_SERVICE_ERR ||
197 	    r == PAM_BUF_ERR ||
198 	    r == PAM_CONV_ERR ||
199 	    r == PAM_PERM_DENIED ||
200 	    r == PAM_ABORT)
201 		return;
202 
203 	/* specific error codes */
204 	switch (primitive) {
205 	case PAM_SM_AUTHENTICATE:
206 		if (r == PAM_AUTH_ERR ||
207 		    r == PAM_CRED_INSUFFICIENT ||
208 		    r == PAM_AUTHINFO_UNAVAIL ||
209 		    r == PAM_USER_UNKNOWN ||
210 		    r == PAM_MAXTRIES)
211 			return;
212 		break;
213 	case PAM_SM_SETCRED:
214 		if (r == PAM_CRED_UNAVAIL ||
215 		    r == PAM_CRED_EXPIRED ||
216 		    r == PAM_USER_UNKNOWN ||
217 		    r == PAM_CRED_ERR)
218 			return;
219 		break;
220 	case PAM_SM_ACCT_MGMT:
221 		if (r == PAM_USER_UNKNOWN ||
222 		    r == PAM_AUTH_ERR ||
223 		    r == PAM_NEW_AUTHTOK_REQD ||
224 		    r == PAM_ACCT_EXPIRED)
225 			return;
226 		break;
227 	case PAM_SM_OPEN_SESSION:
228 	case PAM_SM_CLOSE_SESSION:
229 		if (r == PAM_SESSION_ERR)
230 			return;
231 		break;
232 	case PAM_SM_CHAUTHTOK:
233 		if (r == PAM_PERM_DENIED ||
234 		    r == PAM_AUTHTOK_ERR ||
235 		    r == PAM_AUTHTOK_RECOVERY_ERR ||
236 		    r == PAM_AUTHTOK_LOCK_BUSY ||
237 		    r == PAM_AUTHTOK_DISABLE_AGING ||
238 		    r == PAM_TRY_AGAIN)
239 			return;
240 		break;
241 	}
242 
243 	openpam_log(PAM_LOG_ERROR, "%s(): unexpected return value %d",
244 	    pam_sm_func_name[primitive], r);
245 }
246 #endif /* !defined(OPENPAM_RELAX_CHECKS) */
247 
248 /*
249  * NODOC
250  *
251  * Error codes:
252  */
253