FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_aes.c
1 /*-
2 * Copyright (c) 2002 Poul-Henning Kamp
3 * Copyright (c) 2002 Networks Associates Technology, Inc.
4 * All rights reserved.
5 *
6 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
7 * and NAI Labs, the Security Research Division of Network Associates, Inc.
8 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
9 * 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 * 3. The names of the authors may not be used to endorse or promote
20 * products derived from this software without specific prior written
21 * permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * This method provides AES encryption with a compiled in key (default
36 * all zeroes).
37 *
38 * XXX: This could probably save a lot of code by pretending to be a slicer.
39 */
40
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD: releng/5.2/sys/geom/geom_aes.c 116196 2003-06-11 06:49:16Z obrien $");
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/conf.h>
48 #include <sys/bio.h>
49 #include <sys/malloc.h>
50 #include <sys/lock.h>
51 #include <sys/mutex.h>
52 #include <sys/libkern.h>
53 #include <sys/endian.h>
54 #include <sys/md5.h>
55 #include <sys/errno.h>
56 #include <geom/geom.h>
57
58 #include <crypto/rijndael/rijndael.h>
59
60 #include <crypto/rijndael/rijndael.h>
61
62 #define AES_CLASS_NAME "AES"
63
64 #define MASTER_KEY_LENGTH (1024/8)
65
66 static const u_char *aes_magic = "<<FreeBSD-GEOM-AES>>";
67 static const u_char *aes_magic_random = "<<FreeBSD-GEOM-AES-RANDOM>>";
68 static const u_char *aes_magic_test = "<<FreeBSD-GEOM-AES-TEST>>";
69
70
71 struct g_aes_softc {
72 enum {
73 KEY_ZERO,
74 KEY_RANDOM,
75 KEY_TEST
76 } keying;
77 u_int sectorsize;
78 off_t mediasize;
79 cipherInstance ci;
80 u_char master_key[MASTER_KEY_LENGTH];
81 };
82
83 /*
84 * Generate a sectorkey from the masterkey and the offset position.
85 *
86 * For KEY_ZERO we just return a key of all zeros.
87 *
88 * We feed the sector byte offset, 16 bytes of the master-key and
89 * the sector byte offset once more to MD5.
90 * The sector byte offset is converted to little-endian format first
91 * to support multi-architecture operation.
92 * We use 16 bytes from the master-key starting at the logical sector
93 * number modulus he length of the master-key. If need be we wrap
94 * around to the start of the master-key.
95 */
96
97 static void
98 g_aes_makekey(struct g_aes_softc *sc, off_t off, keyInstance *ki, int dir)
99 {
100 MD5_CTX cx;
101 u_int64_t u64;
102 u_int u, u1;
103 u_char *p, buf[16];
104
105 if (sc->keying == KEY_ZERO) {
106 rijndael_makeKey(ki, dir, 128, sc->master_key);
107 return;
108 }
109 MD5Init(&cx);
110 u64 = htole64(off);
111 MD5Update(&cx, (u_char *)&u64, sizeof(u64));
112 u = off / sc->sectorsize;
113 u %= sizeof sc->master_key;
114 p = sc->master_key + u;
115 if (u + 16 <= sizeof(sc->master_key)) {
116 MD5Update(&cx, p, 16);
117 } else {
118 u1 = sizeof sc->master_key - u;
119 MD5Update(&cx, p, u1);
120 MD5Update(&cx, sc->master_key, 16 - u1);
121 u1 = 0; /* destroy evidence */
122 }
123 u = 0; /* destroy evidence */
124 MD5Update(&cx, (u_char *)&u64, sizeof(u64));
125 u64 = 0; /* destroy evidence */
126 MD5Final(buf, &cx);
127 bzero(&cx, sizeof cx); /* destroy evidence */
128 rijndael_makeKey(ki, dir, 128, buf);
129 bzero(buf, sizeof buf); /* destroy evidence */
130
131 }
132
133 static void
134 g_aes_read_done(struct bio *bp)
135 {
136 struct g_geom *gp;
137 struct g_aes_softc *sc;
138 u_char *p, *b, *e, *sb;
139 keyInstance dkey;
140 off_t o;
141
142 gp = bp->bio_from->geom;
143 sc = gp->softc;
144 sb = g_malloc(sc->sectorsize, M_WAITOK);
145 b = bp->bio_data;
146 e = bp->bio_data;
147 e += bp->bio_length;
148 o = bp->bio_offset - sc->sectorsize;
149 for (p = b; p < e; p += sc->sectorsize) {
150 g_aes_makekey(sc, o, &dkey, DIR_DECRYPT);
151 rijndael_blockDecrypt(&sc->ci, &dkey, p, sc->sectorsize * 8, sb);
152 bcopy(sb, p, sc->sectorsize);
153 o += sc->sectorsize;
154 }
155 bzero(&dkey, sizeof dkey); /* destroy evidence */
156 bzero(sb, sc->sectorsize); /* destroy evidence */
157 g_free(sb);
158 g_std_done(bp);
159 }
160
161 static void
162 g_aes_write_done(struct bio *bp)
163 {
164
165 bzero(bp->bio_data, bp->bio_length); /* destroy evidence */
166 g_free(bp->bio_data);
167 g_std_done(bp);
168 }
169
170 static void
171 g_aes_start(struct bio *bp)
172 {
173 struct g_geom *gp;
174 struct g_consumer *cp;
175 struct g_aes_softc *sc;
176 struct bio *bp2;
177 u_char *p1, *p2, *b, *e;
178 keyInstance ekey;
179 off_t o;
180
181 gp = bp->bio_to->geom;
182 cp = LIST_FIRST(&gp->consumer);
183 sc = gp->softc;
184 switch (bp->bio_cmd) {
185 case BIO_READ:
186 bp2 = g_clone_bio(bp);
187 if (bp2 == NULL) {
188 g_io_deliver(bp, ENOMEM);
189 return;
190 }
191 bp2->bio_done = g_aes_read_done;
192 bp2->bio_offset += sc->sectorsize;
193 g_io_request(bp2, cp);
194 break;
195 case BIO_WRITE:
196 bp2 = g_clone_bio(bp);
197 if (bp2 == NULL) {
198 g_io_deliver(bp, ENOMEM);
199 return;
200 }
201 bp2->bio_done = g_aes_write_done;
202 bp2->bio_offset += sc->sectorsize;
203 bp2->bio_data = g_malloc(bp->bio_length, M_WAITOK);
204 b = bp->bio_data;
205 e = bp->bio_data;
206 e += bp->bio_length;
207 p2 = bp2->bio_data;
208 o = bp->bio_offset;
209 for (p1 = b; p1 < e; p1 += sc->sectorsize) {
210 g_aes_makekey(sc, o, &ekey, DIR_ENCRYPT);
211 rijndael_blockEncrypt(&sc->ci, &ekey,
212 p1, sc->sectorsize * 8, p2);
213 p2 += sc->sectorsize;
214 o += sc->sectorsize;
215 }
216 bzero(&ekey, sizeof ekey); /* destroy evidence */
217 g_io_request(bp2, cp);
218 break;
219 case BIO_GETATTR:
220 bp2 = g_clone_bio(bp);
221 if (bp2 == NULL) {
222 g_io_deliver(bp, ENOMEM);
223 return;
224 }
225 bp2->bio_done = g_std_done;
226 bp2->bio_offset += sc->sectorsize;
227 g_io_request(bp2, cp);
228 break;
229 default:
230 g_io_deliver(bp, EOPNOTSUPP);
231 return;
232 }
233 return;
234 }
235
236 static void
237 g_aes_orphan(struct g_consumer *cp)
238 {
239 struct g_geom *gp;
240 struct g_aes_softc *sc;
241
242 g_trace(G_T_TOPOLOGY, "g_aes_orphan(%p/%s)", cp, cp->provider->name);
243 g_topology_assert();
244 KASSERT(cp->provider->error != 0,
245 ("g_aes_orphan with error == 0"));
246
247 gp = cp->geom;
248 sc = gp->softc;
249 g_wither_geom(gp, cp->provider->error);
250 bzero(sc, sizeof(struct g_aes_softc)); /* destroy evidence */
251 g_free(sc);
252 return;
253 }
254
255 static int
256 g_aes_access(struct g_provider *pp, int dr, int dw, int de)
257 {
258 struct g_geom *gp;
259 struct g_consumer *cp;
260
261 gp = pp->geom;
262 cp = LIST_FIRST(&gp->consumer);
263 /* On first open, grab an extra "exclusive" bit */
264 if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0)
265 de++;
266 /* ... and let go of it on last close */
267 if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1)
268 de--;
269 return (g_access_rel(cp, dr, dw, de));
270 }
271
272 static struct g_geom *
273 g_aes_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
274 {
275 struct g_geom *gp;
276 struct g_consumer *cp;
277 struct g_aes_softc *sc;
278 int error;
279 u_int sectorsize;
280 off_t mediasize;
281 u_char *buf;
282
283 g_trace(G_T_TOPOLOGY, "aes_taste(%s,%s)", mp->name, pp->name);
284 g_topology_assert();
285 gp = g_new_geomf(mp, "%s.aes", pp->name);
286 gp->start = g_aes_start;
287 gp->orphan = g_aes_orphan;
288 gp->spoiled = g_std_spoiled;
289 cp = g_new_consumer(gp);
290 g_attach(cp, pp);
291 error = g_access_rel(cp, 1, 0, 0);
292 if (error) {
293 g_detach(cp);
294 g_destroy_consumer(cp);
295 g_destroy_geom(gp);
296 return (NULL);
297 }
298 buf = NULL;
299 g_topology_unlock();
300 do {
301 if (gp->rank != 2)
302 break;
303 sectorsize = cp->provider->sectorsize;
304 mediasize = cp->provider->mediasize;
305 buf = g_read_data(cp, 0, sectorsize, &error);
306 if (buf == NULL || error != 0) {
307 break;
308 }
309 sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO);
310 if (!memcmp(buf, aes_magic, strlen(aes_magic))) {
311 sc->keying = KEY_ZERO;
312 } else if (!memcmp(buf, aes_magic_random,
313 strlen(aes_magic_random))) {
314 sc->keying = KEY_RANDOM;
315 } else if (!memcmp(buf, aes_magic_test,
316 strlen(aes_magic_test))) {
317 sc->keying = KEY_TEST;
318 } else {
319 g_free(sc);
320 break;
321 }
322 g_free(buf);
323 gp->softc = sc;
324 gp->access = g_aes_access;
325 sc->sectorsize = sectorsize;
326 sc->mediasize = mediasize - sectorsize;
327 rijndael_cipherInit(&sc->ci, MODE_CBC, NULL);
328 if (sc->keying == KEY_TEST) {
329 int i;
330 u_char *p;
331
332 p = sc->master_key;
333 for (i = 0; i < (int)sizeof sc->master_key; i ++)
334 *p++ = i;
335 }
336 if (sc->keying == KEY_RANDOM) {
337 int i;
338 u_int32_t u;
339 u_char *p;
340
341 p = sc->master_key;
342 for (i = 0; i < (int)sizeof sc->master_key; i += sizeof u) {
343 u = arc4random();
344 *p++ = u;
345 *p++ = u >> 8;
346 *p++ = u >> 16;
347 *p++ = u >> 24;
348 }
349 }
350 g_topology_lock();
351 pp = g_new_providerf(gp, gp->name);
352 pp->mediasize = mediasize - sectorsize;
353 pp->sectorsize = sectorsize;
354 g_error_provider(pp, 0);
355 g_topology_unlock();
356 } while(0);
357 g_topology_lock();
358 if (buf)
359 g_free(buf);
360 g_access_rel(cp, -1, 0, 0);
361 if (gp->softc != NULL)
362 return (gp);
363 g_detach(cp);
364 g_destroy_consumer(cp);
365 g_destroy_geom(gp);
366 return (NULL);
367 }
368
369 static struct g_class g_aes_class = {
370 .name = AES_CLASS_NAME,
371 .taste = g_aes_taste,
372 };
373
374 DECLARE_GEOM_CLASS(g_aes_class, g_aes);
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