source: openpam/trunk/lib/openpam_load.c @ 63

Last change on this file since 63 was 63, checked in by des, 13 years ago

Add in-line documentation. Some functions still lack descriptions.

Sponsored by: DARPA, NAI Labs

File size: 5.6 KB
Line 
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
45#ifdef OPENPAM_STATIC_MODULES
46SET_DECLARE(_openpam_modules, pam_module_t);
47#endif
48
49const char *_pam_sm_func_name[PAM_NUM_PRIMITIVES] = {
50        "pam_sm_authenticate",
51        "pam_sm_setcred",
52        "pam_sm_acct_mgmt",
53        "pam_sm_open_session",
54        "pam_sm_close_session",
55        "pam_sm_chauthtok"
56};
57
58static pam_module_t *modules;
59
60/*
61 * Load a dynamic module, or locate a static one.  Keep a list of
62 * previously found modules to speed up the process.
63 */
64
65static pam_module_t *
66openpam_load_module(const char *path)
67{
68        pam_module_t *module;
69        void *dlh;
70        int i;
71
72        /* check cache first */
73        for (module = modules; module != NULL; module = module->next)
74                if (strcmp(module->path, path) == 0)
75                        goto found;
76
77        /* nope; try to load */
78        if ((dlh = dlopen(path, RTLD_NOW)) == NULL) {
79                openpam_log(PAM_LOG_ERROR, "dlopen(): %s", dlerror());
80        } else {
81                if ((module = calloc(1, sizeof *module)) == NULL)
82                        goto buf_err;
83                if ((module->path = strdup(path)) == NULL)
84                        goto buf_err;
85                module->dlh = dlh;
86                for (i = 0; i < PAM_NUM_PRIMITIVES; ++i)
87                        module->func[i] = dlsym(dlh, _pam_sm_func_name[i]);
88        }
89        openpam_log(PAM_LOG_DEBUG, "%s dynamic %s",
90            (module == NULL) ? "no" : "using", path);
91
92#ifdef OPENPAM_STATIC_MODULES
93        /* look for a static module */
94        if (module == NULL && strchr(path, '/') == NULL) {
95                pam_module_t **modp;
96               
97                SET_FOREACH(modp, _openpam_modules) {
98                        if (strcmp((*modp)->path, path) == 0) {
99                                module = *modp;
100                                break;
101                        }
102                }
103                openpam_log(PAM_LOG_DEBUG, "%s static %s",
104                    (module == NULL) ? "no" : "using", path);
105        }
106#endif
107        if (module == NULL)
108                return (NULL);
109        module->next = modules;
110        module->prev = NULL;
111        modules = module;
112 found:
113        ++module->refcount;
114        return (module);
115 buf_err:
116        openpam_log(PAM_LOG_ERROR, "malloc(): %m");
117        dlclose(dlh);
118        free(module);
119        return (NULL);
120}
121
122
123/*
124 * Release a module.
125 * XXX highly thread-unsafe
126 */
127
128static void
129openpam_release_module(pam_module_t *module)
130{
131        if (module == NULL)
132                return;
133        --module->refcount;
134        if (module->refcount > 0)
135                /* still in use */
136                return;
137        if (module->refcount < 0) {
138                openpam_log(PAM_LOG_ERROR, "module %s has negative refcount",
139                    module->path);
140                module->refcount = 0;
141        }
142        if (module->dlh == NULL)
143                /* static module */
144                return;
145        dlclose(module->dlh);
146        if (module->prev != NULL)
147                module->prev->next = module->next;
148        if (module->next != NULL)
149                module->next->prev = module->prev;
150        free(module);
151}
152
153
154/*
155 * Destroy a chain, freeing all its links and releasing the modules
156 * they point to.
157 */
158
159static void
160openpam_destroy_chain(pam_chain_t *chain)
161{
162        if (chain == NULL)
163                return;
164        openpam_destroy_chain(chain->next);
165        chain->next = NULL;
166        while (chain->optc--)
167                free(chain->optv[chain->optc]);
168        free(chain->optv);
169        openpam_release_module(chain->module);
170        free(chain);
171}
172
173/*
174 * Add a module to a chain.
175 */
176
177int
178openpam_add_module(pam_handle_t *pamh,
179        int chain,
180        int flag,
181        const char *modpath,
182        int optc,
183        const char *optv[])
184{
185        pam_chain_t *new, *iterator;
186
187        if ((new = calloc(1, sizeof *new)) == NULL)
188                goto buf_err;
189        if ((new->optv = malloc(sizeof(char *) * (optc + 1))) == NULL)
190                goto buf_err;
191        while (optc--)
192                if ((new->optv[new->optc++] = strdup(*optv++)) == NULL)
193                        goto buf_err;
194        new->optv[new->optc] = NULL;
195        new->flag = flag;
196        if ((new->module = openpam_load_module(modpath)) == NULL) {
197                openpam_destroy_chain(new);
198                return (PAM_OPEN_ERR);
199        }
200        if ((iterator = pamh->chains[chain]) != NULL) {
201                while (iterator->next != NULL)
202                        iterator = iterator->next;
203                iterator->next = new;
204        } else {
205                pamh->chains[chain] = new;
206        }
207        return (PAM_SUCCESS);
208
209 buf_err:
210        openpam_log(PAM_LOG_ERROR, "%m");
211        openpam_destroy_chain(new);
212        return (PAM_BUF_ERR);
213}
214
215
216/*
217 * Clear the chains and release the modules
218 */
219
220void
221openpam_clear_chains(pam_handle_t *pamh)
222{
223        int i;
224
225        for (i = 0; i < PAM_NUM_CHAINS; ++i)
226                openpam_destroy_chain(pamh->chains[i]);
227}
228
229/*
230 * NOPARSE
231 */
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