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 |
52 | secmodel_nsecmodels(void) |
53 | { |
54 | |
55 | return nsecmodels; |
56 | } |
57 | |
58 | 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 |
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 |
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 |
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 |
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 |
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 |
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 |
230 | secmodel_setinfo(const char *id, void *v, int *err) |
231 | { |
232 | |
233 | return EOPNOTSUPP; |
234 | } |
235 | |
236 | int |
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 | |