1 | /*- |
2 | * Copyright (c) 2004 Networks Associates Technology, Inc. |
3 | * Copyright (c) 2005 SPARTA, Inc. |
4 | * All rights reserved. |
5 | * |
6 | * This software was developed for the FreeBSD Project in part by Network |
7 | * Associates Laboratories, the Security Research Division of Network |
8 | * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), |
9 | * 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 | * |
20 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
21 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
24 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
25 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
26 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
29 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
30 | * SUCH DAMAGE. |
31 | */ |
32 | |
33 | #include <kern/zalloc.h> |
34 | #include <security/_label.h> |
35 | #include <sys/param.h> |
36 | #include <sys/queue.h> |
37 | #include <sys/systm.h> |
38 | #include <security/mac_internal.h> |
39 | |
40 | ZONE_DEFINE_ID(ZONE_ID_MAC_LABEL, "MAC Labels" , struct label, |
41 | ZC_READONLY | ZC_ZFREE_CLEARMEM); |
42 | |
43 | /* |
44 | * Number of initial values matches logic in security/_label.h |
45 | */ |
46 | const struct label empty_label = { |
47 | .l_perpolicy[0 ... MAC_MAX_SLOTS - 1] = MAC_LABEL_NULL_SLOT, |
48 | }; |
49 | |
50 | static struct label * |
51 | label_alloc_noinit(int flags) |
52 | { |
53 | static_assert(MAC_NOWAIT == Z_NOWAIT); |
54 | return zalloc_ro(ZONE_ID_MAC_LABEL, Z_ZERO | (flags & MAC_NOWAIT)); |
55 | } |
56 | |
57 | struct label * |
58 | mac_labelzone_alloc(int flags) |
59 | { |
60 | struct label *label; |
61 | |
62 | label = label_alloc_noinit(flags); |
63 | if (label) { |
64 | zalloc_ro_update_elem(ZONE_ID_MAC_LABEL, label, &empty_label); |
65 | } |
66 | |
67 | return label; |
68 | } |
69 | |
70 | struct label * |
71 | mac_labelzone_alloc_for_owner(struct label **labelp, int flags, |
72 | void (^)(struct label *)) |
73 | { |
74 | struct label *label; |
75 | |
76 | if (labelp) { |
77 | struct label tmp_label = empty_label; |
78 | |
79 | label = zalloc_ro(ZONE_ID_MAC_LABEL, Z_ZERO | (flags & MAC_NOWAIT)); |
80 | |
81 | tmp_label.l_owner = labelp; |
82 | zalloc_ro_update_elem(ZONE_ID_MAC_LABEL, label, &tmp_label); |
83 | } else { |
84 | label = mac_labelzone_alloc(flags); |
85 | } |
86 | |
87 | if (label && extra_setup) { |
88 | extra_setup(label); |
89 | } |
90 | |
91 | return label; |
92 | } |
93 | |
94 | struct label * |
95 | mac_labelzone_alloc_owned(struct label **labelp, int flags, |
96 | void (^)(struct label *)) |
97 | { |
98 | struct label *label; |
99 | |
100 | label = mac_labelzone_alloc_for_owner(labelp, flags, extra_setup); |
101 | |
102 | if (labelp) { |
103 | *labelp = label; |
104 | } |
105 | |
106 | return label; |
107 | } |
108 | |
109 | void |
110 | mac_labelzone_free(struct label *label) |
111 | { |
112 | if (label == NULL) { |
113 | panic("Free of NULL MAC label" ); |
114 | } |
115 | |
116 | zfree_ro(ZONE_ID_MAC_LABEL, label); |
117 | } |
118 | |
119 | void |
120 | mac_labelzone_free_owned(struct label **labelp, |
121 | void (^)(struct label *)) |
122 | { |
123 | struct label *label; |
124 | |
125 | label = mac_label_verify(labelp); |
126 | if (label) { |
127 | if (extra_deinit) { |
128 | extra_deinit(label); |
129 | } |
130 | |
131 | *labelp = NULL; |
132 | mac_labelzone_free(label); |
133 | } |
134 | } |
135 | |
136 | __abortlike |
137 | static void |
138 | mac_label_verify_panic(struct label **labelp) |
139 | { |
140 | panic("label backref mismatch: labelp:%p label:%p l_owner:%p" , labelp, |
141 | *labelp, (*labelp)->l_owner); |
142 | } |
143 | |
144 | struct label * |
145 | mac_label_verify(struct label **labelp) |
146 | { |
147 | struct label *label = *labelp; |
148 | |
149 | if (label != NULL) { |
150 | zone_require_ro(zone_id: ZONE_ID_MAC_LABEL, elem_size: sizeof(struct label), addr: label); |
151 | |
152 | if (__improbable(label->l_owner != labelp)) { |
153 | mac_label_verify_panic(labelp); |
154 | } |
155 | } |
156 | |
157 | return label; |
158 | } |
159 | |
160 | static intptr_t |
161 | mac_label_slot_encode(intptr_t p) |
162 | { |
163 | return p ?: MAC_LABEL_NULL_SLOT; |
164 | } |
165 | |
166 | static intptr_t |
167 | mac_label_slot_decode(intptr_t p) |
168 | { |
169 | switch (p) { |
170 | case 0: |
171 | /* make sure 0 doesn't mean NULL and causes crashes */ |
172 | return MAC_LABEL_NULL_SLOT; |
173 | case MAC_LABEL_NULL_SLOT: |
174 | return 0l; |
175 | default: |
176 | return p; |
177 | } |
178 | } |
179 | |
180 | /* |
181 | * Functions used by policy modules to get and set label values. |
182 | */ |
183 | intptr_t |
184 | mac_label_get(struct label *label, int slot) |
185 | { |
186 | KASSERT(label != NULL, ("mac_label_get: NULL label" )); |
187 | |
188 | zone_require_ro(zone_id: ZONE_ID_MAC_LABEL, elem_size: sizeof(struct label), addr: label); |
189 | return mac_label_slot_decode(p: (intptr_t) label->l_perpolicy[slot]); |
190 | } |
191 | |
192 | __abortlike |
193 | static void |
194 | panic_label_set_sentinel(void) |
195 | { |
196 | panic("cannot set mac label to ~0" ); |
197 | } |
198 | |
199 | void |
200 | mac_label_set(struct label *label, int slot, intptr_t v) |
201 | { |
202 | KASSERT(label != NULL, ("mac_label_set: NULL label" )); |
203 | |
204 | #if DEVELOPMENT || DEBUG |
205 | /* can't modify a sealed label, see mac_cred_label_seal() */ |
206 | assertf(label->l_owner != (struct label **)-1, |
207 | "mac_label_set(%p, %d, 0x%lx) is sealed" , |
208 | label, slot, v); |
209 | #endif |
210 | if (v == MAC_LABEL_NULL_SLOT) { |
211 | panic_label_set_sentinel(); |
212 | } |
213 | v = mac_label_slot_encode(p: v); |
214 | zalloc_ro_update_field(ZONE_ID_MAC_LABEL, label, l_perpolicy[slot], &v); |
215 | } |
216 | |