1 /* $NetBSD: secmodel.c,v 1.2 2014/11/04 16:01:58 maxv Exp $ */
2 /*-
3 * Copyright (c) 2011 Elad Efrat <elad@NetBSD.org>
4 * 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 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/types.h>
30 #include <sys/param.h>
31 #include <sys/errno.h>
32
33 #include <sys/atomic.h>
34 #include <sys/kauth.h>
35 #include <sys/kmem.h>
36 #include <sys/queue.h>
37 #include <sys/rwlock.h>
38 #include <secmodel/secmodel.h>
39 #include <prop/proplib.h>
40
41 /* List of secmodels, parameters, and lock. */
42 static LIST_HEAD(, secmodel_descr) secmodels =
43 LIST_HEAD_INITIALIZER(secmodels);
44 static unsigned int secmodel_copy_cred_on_fork = false;
45 static krwlock_t secmodels_lock;
46 static int nsecmodels = 0; /* number of registered secmodels */
47
48 static int secmodel_plug(secmodel_t);
49 static int secmodel_unplug(secmodel_t);
50
51 int
secmodel_nsecmodels(void)52 secmodel_nsecmodels(void)
53 {
54
55 return nsecmodels;
56 }
57
58 void
secmodel_init(void)59 secmodel_init(void)
60 {
61
62 rw_init(&secmodels_lock);
63
64 secmodel_copy_cred_on_fork = false;
65 }
66
67 /*
68 * Register a new secmodel.
69 */
70 int
secmodel_register(secmodel_t * secmodel,const char * id,const char * name,prop_dictionary_t behavior,secmodel_eval_t eval,secmodel_setinfo_t setinfo)71 secmodel_register(secmodel_t *secmodel, const char *id, const char *name,
72 prop_dictionary_t behavior,
73 secmodel_eval_t eval, secmodel_setinfo_t setinfo)
74 {
75 int err;
76 secmodel_t sm;
77
78 sm = kmem_alloc(sizeof(*sm), KM_SLEEP);
79
80 sm->sm_id = id;
81 sm->sm_name = name;
82 sm->sm_behavior = behavior;
83 sm->sm_eval = eval;
84 sm->sm_setinfo = setinfo;
85
86 err = secmodel_plug(sm);
87 if (err == 0) {
88 atomic_inc_uint(&nsecmodels);
89 } else {
90 kmem_free(sm, sizeof(*sm));
91 sm = NULL;
92 }
93
94 *secmodel = sm;
95 return err;
96 }
97
98 /*
99 * Deregister a secmodel.
100 */
101 int
secmodel_deregister(secmodel_t sm)102 secmodel_deregister(secmodel_t sm)
103 {
104 int error;
105
106 error = secmodel_unplug(sm);
107 if (error == 0) {
108 atomic_dec_uint(&nsecmodels);
109 kmem_free(sm, sizeof(*sm));
110 }
111
112 return error;
113 }
114
115 /*
116 * Lookup a secmodel by its id.
117 *
118 * Requires "secmodels_lock" handling by the caller.
119 */
120 static secmodel_t
secmodel_lookup(const char * id)121 secmodel_lookup(const char *id)
122 {
123 secmodel_t tsm;
124
125 KASSERT(rw_lock_held(&secmodels_lock));
126
127 LIST_FOREACH(tsm, &secmodels, sm_list) {
128 if (strcasecmp(tsm->sm_id, id) == 0) {
129 return tsm;
130 }
131 }
132
133 return NULL;
134 }
135
136 /*
137 * Adjust system-global secmodel behavior following the addition
138 * or removal of a secmodel.
139 *
140 * Requires "secmodels_lock" to be held by the caller.
141 */
142 static void
secmodel_adjust_behavior(secmodel_t sm,bool added)143 secmodel_adjust_behavior(secmodel_t sm, bool added)
144 {
145 bool r, b;
146
147 KASSERT(rw_write_held(&secmodels_lock));
148
149 #define ADJUST_COUNTER(which, added) \
150 do { \
151 if (added) { \
152 (which)++; \
153 } else { \
154 if ((which) > 0) \
155 (which)--; \
156 } \
157 } while (/*CONSTCOND*/0)
158
159 /* Copy credentials on fork? */
160 r = prop_dictionary_get_bool(sm->sm_behavior, "copy-cred-on-fork", &b);
161 if (r) {
162 ADJUST_COUNTER(secmodel_copy_cred_on_fork, added);
163 }
164
165 #undef ADJUST_COUNTER
166 }
167
168 static int
secmodel_plug(secmodel_t sm)169 secmodel_plug(secmodel_t sm)
170 {
171 secmodel_t tsm;
172 int error = 0;
173
174 if (sm == NULL)
175 return EFAULT;
176
177 /* Check if the secmodel is already present. */
178 rw_enter(&secmodels_lock, RW_WRITER);
179 tsm = secmodel_lookup(sm->sm_id);
180 if (tsm != NULL) {
181 error = EEXIST;
182 goto out;
183 }
184
185 /* Add the secmodel. */
186 LIST_INSERT_HEAD(&secmodels, sm, sm_list);
187
188 /* Adjust behavior. */
189 secmodel_adjust_behavior(sm, true);
190
191 out:
192 /* Unlock the secmodels list. */
193 rw_exit(&secmodels_lock);
194
195 return error;
196 }
197
198 static int
secmodel_unplug(secmodel_t sm)199 secmodel_unplug(secmodel_t sm)
200 {
201 secmodel_t tsm;
202 int error = 0;
203
204 if (sm == NULL)
205 return EFAULT;
206
207 /* Make sure the secmodel is present. */
208 rw_enter(&secmodels_lock, RW_WRITER);
209 tsm = secmodel_lookup(sm->sm_id);
210 if (tsm == NULL) {
211 error = ENOENT;
212 goto out;
213 }
214
215 /* Remove the secmodel. */
216 LIST_REMOVE(tsm, sm_list);
217
218 /* Adjust behavior. */
219 secmodel_adjust_behavior(tsm, false);
220
221 out:
222 /* Unlock the secmodels list. */
223 rw_exit(&secmodels_lock);
224
225 return error;
226 }
227
228 /* XXX TODO */
229 int
secmodel_setinfo(const char * id,void * v,int * err)230 secmodel_setinfo(const char *id, void *v, int *err)
231 {
232
233 return EOPNOTSUPP;
234 }
235
236 int
secmodel_eval(const char * id,const char * what,void * arg,void * ret)237 secmodel_eval(const char *id, const char *what, void *arg, void *ret)
238 {
239 secmodel_t sm;
240 int error = 0;
241
242 rw_enter(&secmodels_lock, RW_READER);
243 sm = secmodel_lookup(id);
244 if (sm == NULL) {
245 error = EINVAL;
246 goto out;
247 }
248
249 if (sm->sm_eval == NULL) {
250 error = ENOENT;
251 goto out;
252 }
253
254 if (ret == NULL) {
255 error = EFAULT;
256 goto out;
257 }
258
259 error = sm->sm_eval(what, arg, ret);
260 /* pass error from a secmodel(9) callback as a negative value */
261 error = -error;
262
263 out:
264 rw_exit(&secmodels_lock);
265
266 return error;
267 }
268