openpam_load.c revision 91100 
1/*-
2 * Copyright (c) 2002 Networks Associates Technologies, Inc.
3 * All rights reserved.
4 *
5 * This software was developed for the FreeBSD Project by ThinkSec AS and
6 * NAI Labs, the Security Research Division of Network Associates, Inc.
7 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
8 * DARPA CHATS research program.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote
19 *    products derived from this software without specific prior written
20 *    permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * $Id$
35 */
36
37#include <dlfcn.h>
38#include <stdlib.h>
39#include <string.h>
40
41#include <security/pam_appl.h>
42
43#include "openpam_impl.h"
44
45const char *_pam_sm_func_name[PAM_NUM_PRIMITIVES] = {
46	"pam_sm_authenticate",
47	"pam_sm_setcred",
48	"pam_sm_acct_mgmt",
49	"pam_sm_open_session",
50	"pam_sm_close_session",
51	"pam_sm_chauthtok"
52};
53
54static pam_module_t *modules;
55
56/*
57 * Load a dynamic module, or locate a static one.  Keep a list of
58 * previously found modules to speed up the process.
59 */
60
61static pam_module_t *
62openpam_load_module(const char *path)
63{
64	pam_module_t *module;
65	void *dlh;
66	int i;
67
68	/* check cache first */
69	for (module = modules; module != NULL; module = module->next)
70		if (strcmp(module->path, path) == 0)
71			goto found;
72
73	/* nope; try to load */
74	if ((dlh = dlopen(path, RTLD_NOW)) == NULL) {
75		openpam_log(PAM_LOG_ERROR, "dlopen(): %s", dlerror());
76	} else {
77		if ((module = calloc(1, sizeof *module)) == NULL)
78			goto buf_err;
79		if ((module->path = strdup(path)) == NULL)
80			goto buf_err;
81		module->dlh = dlh;
82		for (i = 0; i < PAM_NUM_PRIMITIVES; ++i)
83			module->func[i] = dlsym(dlh, _pam_sm_func_name[i]);
84	}
85	openpam_log(PAM_LOG_DEBUG, "%s dynamic %s",
86	    (module == NULL) ? "no" : "using", path);
87
88#ifdef OPENPAM_STATIC_MODULES
89	/* look for a static module */
90	if (module == NULL && strchr(path, '/') == NULL) {
91		module = openpam_static(path);
92		openpam_log(PAM_LOG_DEBUG, "%s static %s",
93		    (module == NULL) ? "no" : "using", path);
94	}
95#endif
96	if (module == NULL)
97		return (NULL);
98	module->next = modules;
99	module->prev = NULL;
100	modules = module;
101 found:
102	++module->refcount;
103	return (module);
104 buf_err:
105	openpam_log(PAM_LOG_ERROR, "malloc(): %m");
106	dlclose(dlh);
107	free(module);
108	return (NULL);
109}
110
111
112/*
113 * Release a module.
114 * XXX highly thread-unsafe
115 */
116
117static void
118openpam_release_module(pam_module_t *module)
119{
120	if (module == NULL)
121		return;
122	--module->refcount;
123	if (module->refcount > 0)
124		/* still in use */
125		return;
126	if (module->refcount < 0) {
127		openpam_log(PAM_LOG_ERROR, "module %s has negative refcount",
128		    module->path);
129		module->refcount = 0;
130	}
131	if (module->dlh == NULL)
132		/* static module */
133		return;
134	dlclose(module->dlh);
135	if (module->prev != NULL)
136		module->prev->next = module->next;
137	if (module->next != NULL)
138		module->next->prev = module->prev;
139	free(module);
140}
141
142
143/*
144 * Destroy a chain, freeing all its links and releasing the modules
145 * they point to.
146 */
147
148static void
149openpam_destroy_chain(pam_chain_t *chain)
150{
151	if (chain == NULL)
152		return;
153	openpam_destroy_chain(chain->next);
154	chain->next = NULL;
155	while (chain->optc--)
156		free(chain->optv[chain->optc]);
157	free(chain->optv);
158	openpam_release_module(chain->module);
159	free(chain);
160}
161
162/*
163 * Add a module to a chain.
164 */
165
166int
167openpam_add_module(pam_handle_t *pamh,
168	int chain,
169	int flag,
170	const char *modpath,
171	int optc,
172	const char *optv[])
173{
174	pam_chain_t *new, *iterator;
175
176	if ((new = calloc(1, sizeof *new)) == NULL)
177		goto buf_err;
178	if ((new->optv = malloc(sizeof(char *) * (optc + 1))) == NULL)
179		goto buf_err;
180	while (optc--)
181		if ((new->optv[new->optc++] = strdup(*optv++)) == NULL)
182			goto buf_err;
183	new->optv[new->optc] = NULL;
184	new->flag = flag;
185	if ((new->module = openpam_load_module(modpath)) == NULL) {
186		openpam_destroy_chain(new);
187		return (PAM_OPEN_ERR);
188	}
189	if ((iterator = pamh->chains[chain]) != NULL) {
190		while (iterator->next != NULL)
191			iterator = iterator->next;
192		iterator->next = new;
193	} else {
194		pamh->chains[chain] = new;
195	}
196	return (PAM_SUCCESS);
197
198 buf_err:
199	openpam_log(PAM_LOG_ERROR, "%m");
200	openpam_destroy_chain(new);
201	return (PAM_BUF_ERR);
202}
203
204
205/*
206 * Clear the chains and release the modules
207 */
208
209void
210openpam_clear_chains(pam_handle_t *pamh)
211{
212	int i;
213
214	for (i = 0; i < PAM_NUM_CHAINS; ++i)
215		openpam_destroy_chain(pamh->chains[i]);
216}
217
218/*
219 * NOPARSE
220 */
221