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