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 * $FreeBSD: releng/5.1/sys/geom/geom_aes.c 114736 2003-05-05 15:52:11Z phk $
36 *
37 * This method provides AES encryption with a compiled in key (default
38 * all zeroes).
39 *
40 * XXX: This could probably save a lot of code by pretending to be a slicer.
41 */
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
46 #include <sys/conf.h>
47 #include <sys/bio.h>
48 #include <sys/malloc.h>
49 #include <sys/lock.h>
50 #include <sys/mutex.h>
51 #include <sys/libkern.h>
52 #include <sys/endian.h>
53 #include <sys/md5.h>
54 #include <sys/errno.h>
55 #include <geom/geom.h>
56
57 #include <crypto/rijndael/rijndael.h>
58
59 #include <crypto/rijndael/rijndael.h>
60
61 #define AES_CLASS_NAME "AES"
62
63 #define MASTER_KEY_LENGTH (1024/8)
64
65 static const u_char *aes_magic = "<<FreeBSD-GEOM-AES>>";
66 static const u_char *aes_magic_random = "<<FreeBSD-GEOM-AES-RANDOM>>";
67 static const u_char *aes_magic_test = "<<FreeBSD-GEOM-AES-TEST>>";
68
69
70 struct g_aes_softc {
71 enum {
72 KEY_ZERO,
73 KEY_RANDOM,
74 KEY_TEST
75 } keying;
76 u_int sectorsize;
77 off_t mediasize;
78 cipherInstance ci;
79 u_char master_key[MASTER_KEY_LENGTH];
80 };
81
82 /*
83 * Generate a sectorkey from the masterkey and the offset position.
84 *
85 * For KEY_ZERO we just return a key of all zeros.
86 *
87 * We feed the sector byte offset, 16 bytes of the master-key and
88 * the sector byte offset once more to MD5.
89 * The sector byte offset is converted to little-endian format first
90 * to support multi-architecture operation.
91 * We use 16 bytes from the master-key starting at the logical sector
92 * number modulus he length of the master-key. If need be we wrap
93 * around to the start of the master-key.
94 */
95
96 static void
97 g_aes_makekey(struct g_aes_softc *sc, off_t off, keyInstance *ki, int dir)
98 {
99 MD5_CTX cx;
100 u_int64_t u64;
101 u_int u, u1;
102 u_char *p, buf[16];
103
104 if (sc->keying == KEY_ZERO) {
105 rijndael_makeKey(ki, dir, 128, sc->master_key);
106 return;
107 }
108 MD5Init(&cx);
109 u64 = htole64(off);
110 MD5Update(&cx, (u_char *)&u64, sizeof(u64));
111 u = off / sc->sectorsize;
112 u %= sizeof sc->master_key;
113 p = sc->master_key + u;
114 if (u + 16 <= sizeof(sc->master_key)) {
115 MD5Update(&cx, p, 16);
116 } else {
117 u1 = sizeof sc->master_key - u;
118 MD5Update(&cx, p, u1);
119 MD5Update(&cx, sc->master_key, 16 - u1);
120 u1 = 0; /* destroy evidence */
121 }
122 u = 0; /* destroy evidence */
123 MD5Update(&cx, (u_char *)&u64, sizeof(u64));
124 u64 = 0; /* destroy evidence */
125 MD5Final(buf, &cx);
126 bzero(&cx, sizeof cx); /* destroy evidence */
127 rijndael_makeKey(ki, dir, 128, buf);
128 bzero(buf, sizeof buf); /* destroy evidence */
129
130 }
131
132 static void
133 g_aes_read_done(struct bio *bp)
134 {
135 struct g_geom *gp;
136 struct g_aes_softc *sc;
137 u_char *p, *b, *e, *sb;
138 keyInstance dkey;
139 off_t o;
140
141 gp = bp->bio_from->geom;
142 sc = gp->softc;
143 sb = g_malloc(sc->sectorsize, M_WAITOK);
144 b = bp->bio_data;
145 e = bp->bio_data;
146 e += bp->bio_length;
147 o = bp->bio_offset - sc->sectorsize;
148 for (p = b; p < e; p += sc->sectorsize) {
149 g_aes_makekey(sc, o, &dkey, DIR_DECRYPT);
150 rijndael_blockDecrypt(&sc->ci, &dkey, p, sc->sectorsize * 8, sb);
151 bcopy(sb, p, sc->sectorsize);
152 o += sc->sectorsize;
153 }
154 bzero(&dkey, sizeof dkey); /* destroy evidence */
155 bzero(sb, sc->sectorsize); /* destroy evidence */
156 g_free(sb);
157 g_std_done(bp);
158 }
159
160 static void
161 g_aes_write_done(struct bio *bp)
162 {
163 struct g_aes_softc *sc;
164 struct g_geom *gp;
165
166 gp = bp->bio_to->geom;
167 sc = gp->softc;
168 bzero(bp->bio_data, bp->bio_length); /* destroy evidence */
169 g_free(bp->bio_data);
170 g_std_done(bp);
171 }
172
173 static void
174 g_aes_start(struct bio *bp)
175 {
176 struct g_geom *gp;
177 struct g_consumer *cp;
178 struct g_aes_softc *sc;
179 struct bio *bp2;
180 u_char *p1, *p2, *b, *e;
181 keyInstance ekey;
182 off_t o;
183
184 gp = bp->bio_to->geom;
185 cp = LIST_FIRST(&gp->consumer);
186 sc = gp->softc;
187 switch (bp->bio_cmd) {
188 case BIO_READ:
189 bp2 = g_clone_bio(bp);
190 if (bp2 == NULL) {
191 g_io_deliver(bp, ENOMEM);
192 return;
193 }
194 bp2->bio_done = g_aes_read_done;
195 bp2->bio_offset += sc->sectorsize;
196 g_io_request(bp2, cp);
197 break;
198 case BIO_WRITE:
199 bp2 = g_clone_bio(bp);
200 if (bp2 == NULL) {
201 g_io_deliver(bp, ENOMEM);
202 return;
203 }
204 bp2->bio_done = g_aes_write_done;
205 bp2->bio_offset += sc->sectorsize;
206 bp2->bio_data = g_malloc(bp->bio_length, M_WAITOK);
207 b = bp->bio_data;
208 e = bp->bio_data;
209 e += bp->bio_length;
210 p2 = bp2->bio_data;
211 o = bp->bio_offset;
212 for (p1 = b; p1 < e; p1 += sc->sectorsize) {
213 g_aes_makekey(sc, o, &ekey, DIR_ENCRYPT);
214 rijndael_blockEncrypt(&sc->ci, &ekey,
215 p1, sc->sectorsize * 8, p2);
216 p2 += sc->sectorsize;
217 o += sc->sectorsize;
218 }
219 bzero(&ekey, sizeof ekey); /* destroy evidence */
220 g_io_request(bp2, cp);
221 break;
222 case BIO_GETATTR:
223 bp2 = g_clone_bio(bp);
224 if (bp2 == NULL) {
225 g_io_deliver(bp, ENOMEM);
226 return;
227 }
228 bp2->bio_done = g_std_done;
229 bp2->bio_offset += sc->sectorsize;
230 g_io_request(bp2, cp);
231 break;
232 default:
233 g_io_deliver(bp, EOPNOTSUPP);
234 return;
235 }
236 return;
237 }
238
239 static void
240 g_aes_orphan(struct g_consumer *cp)
241 {
242 struct g_geom *gp;
243 struct g_aes_softc *sc;
244
245 g_trace(G_T_TOPOLOGY, "g_aes_orphan(%p/%s)", cp, cp->provider->name);
246 g_topology_assert();
247 KASSERT(cp->provider->error != 0,
248 ("g_aes_orphan with error == 0"));
249
250 gp = cp->geom;
251 sc = gp->softc;
252 g_wither_geom(gp, cp->provider->error);
253 bzero(sc, sizeof(struct g_aes_softc)); /* destroy evidence */
254 g_free(sc);
255 return;
256 }
257
258 static int
259 g_aes_access(struct g_provider *pp, int dr, int dw, int de)
260 {
261 struct g_geom *gp;
262 struct g_consumer *cp;
263
264 gp = pp->geom;
265 cp = LIST_FIRST(&gp->consumer);
266 /* On first open, grab an extra "exclusive" bit */
267 if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0)
268 de++;
269 /* ... and let go of it on last close */
270 if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1)
271 de--;
272 return (g_access_rel(cp, dr, dw, de));
273 }
274
275 static struct g_geom *
276 g_aes_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
277 {
278 struct g_geom *gp;
279 struct g_consumer *cp;
280 struct g_aes_softc *sc;
281 int error;
282 u_int sectorsize;
283 off_t mediasize;
284 u_char *buf;
285
286 g_trace(G_T_TOPOLOGY, "aes_taste(%s,%s)", mp->name, pp->name);
287 g_topology_assert();
288 gp = g_new_geomf(mp, "%s.aes", pp->name);
289 gp->start = g_aes_start;
290 gp->orphan = g_aes_orphan;
291 gp->spoiled = g_std_spoiled;
292 cp = g_new_consumer(gp);
293 g_attach(cp, pp);
294 error = g_access_rel(cp, 1, 0, 0);
295 if (error) {
296 g_detach(cp);
297 g_destroy_consumer(cp);
298 g_destroy_geom(gp);
299 return (NULL);
300 }
301 buf = NULL;
302 g_topology_unlock();
303 do {
304 if (gp->rank != 2)
305 break;
306 sectorsize = cp->provider->sectorsize;
307 mediasize = cp->provider->mediasize;
308 buf = g_read_data(cp, 0, sectorsize, &error);
309 if (buf == NULL || error != 0) {
310 break;
311 }
312 sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO);
313 if (!memcmp(buf, aes_magic, strlen(aes_magic))) {
314 sc->keying = KEY_ZERO;
315 } else if (!memcmp(buf, aes_magic_random,
316 strlen(aes_magic_random))) {
317 sc->keying = KEY_RANDOM;
318 } else if (!memcmp(buf, aes_magic_test,
319 strlen(aes_magic_test))) {
320 sc->keying = KEY_TEST;
321 } else {
322 g_free(sc);
323 break;
324 }
325 g_free(buf);
326 gp->softc = sc;
327 gp->access = g_aes_access;
328 sc->sectorsize = sectorsize;
329 sc->mediasize = mediasize - sectorsize;
330 rijndael_cipherInit(&sc->ci, MODE_CBC, NULL);
331 if (sc->keying == KEY_TEST) {
332 int i;
333 u_char *p;
334
335 p = sc->master_key;
336 for (i = 0; i < (int)sizeof sc->master_key; i ++)
337 *p++ = i;
338 }
339 if (sc->keying == KEY_RANDOM) {
340 int i;
341 u_int32_t u;
342 u_char *p;
343
344 p = sc->master_key;
345 for (i = 0; i < (int)sizeof sc->master_key; i += sizeof u) {
346 u = arc4random();
347 *p++ = u;
348 *p++ = u >> 8;
349 *p++ = u >> 16;
350 *p++ = u >> 24;
351 }
352 }
353 g_topology_lock();
354 pp = g_new_providerf(gp, gp->name);
355 pp->mediasize = mediasize - sectorsize;
356 pp->sectorsize = sectorsize;
357 g_error_provider(pp, 0);
358 g_topology_unlock();
359 } while(0);
360 g_topology_lock();
361 if (buf)
362 g_free(buf);
363 g_access_rel(cp, -1, 0, 0);
364 if (gp->softc != NULL)
365 return (gp);
366 g_detach(cp);
367 g_destroy_consumer(cp);
368 g_destroy_geom(gp);
369 return (NULL);
370 }
371
372 static struct g_class g_aes_class = {
373 .name = AES_CLASS_NAME,
374 .taste = g_aes_taste,
375 G_CLASS_INITIALIZER
376 };
377
378 DECLARE_GEOM_CLASS(g_aes_class, g_aes);
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