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-api-fst.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 static int g_aes_once;
71
72 struct g_aes_softc {
73 enum {
74 KEY_ZERO,
75 KEY_RANDOM,
76 KEY_TEST
77 } keying;
78 u_int sectorsize;
79 off_t mediasize;
80 cipherInstance ci;
81 u_char master_key[MASTER_KEY_LENGTH];
82 };
83
84 /*
85 * Generate a sectorkey from the masterkey and the offset position.
86 *
87 * For KEY_ZERO we just return a key of all zeros.
88 *
89 * We feed the sector byte offset, 16 bytes of the master-key and
90 * the sector byte offset once more to MD5.
91 * The sector byte offset is converted to little-endian format first
92 * to support multi-architecture operation.
93 * We use 16 bytes from the master-key starting at the logical sector
94 * number modulus he length of the master-key. If need be we wrap
95 * around to the start of the master-key.
96 */
97
98 static void
g_aes_makekey(struct g_aes_softc * sc,off_t off,keyInstance * ki,int dir)99 g_aes_makekey(struct g_aes_softc *sc, off_t off, keyInstance *ki, int dir)
100 {
101 MD5_CTX cx;
102 u_int64_t u64;
103 u_int u, u1;
104 u_char *p, buf[16];
105
106 if (sc->keying == KEY_ZERO) {
107 rijndael_makeKey(ki, dir, 128, sc->master_key);
108 return;
109 }
110 MD5Init(&cx);
111 u64 = htole64(off);
112 MD5Update(&cx, (u_char *)&u64, sizeof(u64));
113 u = off / sc->sectorsize;
114 u %= sizeof sc->master_key;
115 p = sc->master_key + u;
116 if (u + 16 <= sizeof(sc->master_key)) {
117 MD5Update(&cx, p, 16);
118 } else {
119 u1 = sizeof sc->master_key - u;
120 MD5Update(&cx, p, u1);
121 MD5Update(&cx, sc->master_key, 16 - u1);
122 u1 = 0; /* destroy evidence */
123 }
124 u = 0; /* destroy evidence */
125 MD5Update(&cx, (u_char *)&u64, sizeof(u64));
126 u64 = 0; /* destroy evidence */
127 MD5Final(buf, &cx);
128 bzero(&cx, sizeof cx); /* destroy evidence */
129 rijndael_makeKey(ki, dir, 128, buf);
130 bzero(buf, sizeof buf); /* destroy evidence */
131
132 }
133
134 static void
g_aes_read_done(struct bio * bp)135 g_aes_read_done(struct bio *bp)
136 {
137 struct g_geom *gp;
138 struct g_aes_softc *sc;
139 u_char *p, *b, *e, *sb;
140 keyInstance dkey;
141 off_t o;
142
143 gp = bp->bio_from->geom;
144 sc = gp->softc;
145 sb = g_malloc(sc->sectorsize, M_WAITOK);
146 b = bp->bio_data;
147 e = bp->bio_data;
148 e += bp->bio_length;
149 o = bp->bio_offset - sc->sectorsize;
150 for (p = b; p < e; p += sc->sectorsize) {
151 g_aes_makekey(sc, o, &dkey, DIR_DECRYPT);
152 rijndael_blockDecrypt(&sc->ci, &dkey, p, sc->sectorsize * 8, sb);
153 bcopy(sb, p, sc->sectorsize);
154 o += sc->sectorsize;
155 }
156 bzero(&dkey, sizeof dkey); /* destroy evidence */
157 bzero(sb, sc->sectorsize); /* destroy evidence */
158 g_free(sb);
159 g_std_done(bp);
160 }
161
162 static void
g_aes_write_done(struct bio * bp)163 g_aes_write_done(struct bio *bp)
164 {
165
166 bzero(bp->bio_data, bp->bio_length); /* destroy evidence */
167 g_free(bp->bio_data);
168 g_std_done(bp);
169 }
170
171 static void
g_aes_start(struct bio * bp)172 g_aes_start(struct bio *bp)
173 {
174 struct g_geom *gp;
175 struct g_consumer *cp;
176 struct g_aes_softc *sc;
177 struct bio *bp2;
178 u_char *p1, *p2, *b, *e;
179 keyInstance ekey;
180 off_t o;
181
182 gp = bp->bio_to->geom;
183 cp = LIST_FIRST(&gp->consumer);
184 sc = gp->softc;
185 switch (bp->bio_cmd) {
186 case BIO_READ:
187 bp2 = g_clone_bio(bp);
188 if (bp2 == NULL) {
189 g_io_deliver(bp, ENOMEM);
190 return;
191 }
192 bp2->bio_done = g_aes_read_done;
193 bp2->bio_offset += sc->sectorsize;
194 g_io_request(bp2, cp);
195 break;
196 case BIO_WRITE:
197 bp2 = g_clone_bio(bp);
198 if (bp2 == NULL) {
199 g_io_deliver(bp, ENOMEM);
200 return;
201 }
202 bp2->bio_done = g_aes_write_done;
203 bp2->bio_offset += sc->sectorsize;
204 bp2->bio_data = g_malloc(bp->bio_length, M_WAITOK);
205 b = bp->bio_data;
206 e = bp->bio_data;
207 e += bp->bio_length;
208 p2 = bp2->bio_data;
209 o = bp->bio_offset;
210 for (p1 = b; p1 < e; p1 += sc->sectorsize) {
211 g_aes_makekey(sc, o, &ekey, DIR_ENCRYPT);
212 rijndael_blockEncrypt(&sc->ci, &ekey,
213 p1, sc->sectorsize * 8, p2);
214 p2 += sc->sectorsize;
215 o += sc->sectorsize;
216 }
217 bzero(&ekey, sizeof ekey); /* destroy evidence */
218 g_io_request(bp2, cp);
219 break;
220 case BIO_GETATTR:
221 bp2 = g_clone_bio(bp);
222 if (bp2 == NULL) {
223 g_io_deliver(bp, ENOMEM);
224 return;
225 }
226 bp2->bio_done = g_std_done;
227 bp2->bio_offset += sc->sectorsize;
228 g_io_request(bp2, cp);
229 break;
230 default:
231 g_io_deliver(bp, EOPNOTSUPP);
232 return;
233 }
234 return;
235 }
236
237 static void
g_aes_orphan(struct g_consumer * cp)238 g_aes_orphan(struct g_consumer *cp)
239 {
240 struct g_geom *gp;
241 struct g_aes_softc *sc;
242
243 g_trace(G_T_TOPOLOGY, "g_aes_orphan(%p/%s)", cp, cp->provider->name);
244 g_topology_assert();
245
246 gp = cp->geom;
247 sc = gp->softc;
248 g_wither_geom(gp, ENXIO);
249 bzero(sc, sizeof(struct g_aes_softc)); /* destroy evidence */
250 g_free(sc);
251 return;
252 }
253
254 static int
g_aes_access(struct g_provider * pp,int dr,int dw,int de)255 g_aes_access(struct g_provider *pp, int dr, int dw, int de)
256 {
257 struct g_geom *gp;
258 struct g_consumer *cp;
259
260 gp = pp->geom;
261 cp = LIST_FIRST(&gp->consumer);
262 /* On first open, grab an extra "exclusive" bit */
263 if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0)
264 de++;
265 /* ... and let go of it on last close */
266 if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1)
267 de--;
268 return (g_access(cp, dr, dw, de));
269 }
270
271 static struct g_geom *
g_aes_taste(struct g_class * mp,struct g_provider * pp,int flags __unused)272 g_aes_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
273 {
274 struct g_geom *gp;
275 struct g_consumer *cp;
276 struct g_aes_softc *sc;
277 int error;
278 u_int sectorsize;
279 off_t mediasize;
280 u_char *buf;
281
282 g_trace(G_T_TOPOLOGY, "aes_taste(%s,%s)", mp->name, pp->name);
283 g_topology_assert();
284 gp = g_new_geomf(mp, "%s.aes", pp->name);
285 cp = g_new_consumer(gp);
286 g_attach(cp, pp);
287 error = g_access(cp, 1, 0, 0);
288 if (error) {
289 g_detach(cp);
290 g_destroy_consumer(cp);
291 g_destroy_geom(gp);
292 return (NULL);
293 }
294 buf = NULL;
295 g_topology_unlock();
296 do {
297 if (gp->rank != 2)
298 break;
299 sectorsize = cp->provider->sectorsize;
300 mediasize = cp->provider->mediasize;
301 buf = g_read_data(cp, 0, sectorsize, NULL);
302 if (buf == NULL) {
303 break;
304 }
305 sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO);
306 if (!memcmp(buf, aes_magic, strlen(aes_magic))) {
307 sc->keying = KEY_ZERO;
308 } else if (!memcmp(buf, aes_magic_random,
309 strlen(aes_magic_random))) {
310 sc->keying = KEY_RANDOM;
311 } else if (!memcmp(buf, aes_magic_test,
312 strlen(aes_magic_test))) {
313 sc->keying = KEY_TEST;
314 } else {
315 g_free(sc);
316 break;
317 }
318 g_free(buf);
319 gp->softc = sc;
320 sc->sectorsize = sectorsize;
321 sc->mediasize = mediasize - sectorsize;
322 rijndael_cipherInit(&sc->ci, MODE_CBC, NULL);
323 if (sc->keying == KEY_TEST) {
324 int i;
325 u_char *p;
326
327 p = sc->master_key;
328 for (i = 0; i < (int)sizeof sc->master_key; i ++)
329 *p++ = i;
330 }
331 if (sc->keying == KEY_RANDOM) {
332 int i;
333 u_int32_t u;
334 u_char *p;
335
336 p = sc->master_key;
337 for (i = 0; i < (int)sizeof sc->master_key; i += sizeof u) {
338 u = arc4random();
339 *p++ = u;
340 *p++ = u >> 8;
341 *p++ = u >> 16;
342 *p++ = u >> 24;
343 }
344 }
345 g_topology_lock();
346 pp = g_new_providerf(gp, "%s", gp->name);
347 pp->mediasize = mediasize - sectorsize;
348 pp->sectorsize = sectorsize;
349 g_error_provider(pp, 0);
350 g_topology_unlock();
351 } while(0);
352 g_topology_lock();
353 if (buf)
354 g_free(buf);
355 g_access(cp, -1, 0, 0);
356 if (gp->softc != NULL) {
357 if (!g_aes_once) {
358 g_aes_once = 1;
359 printf("WARNING: geom_aes (geom %s) is deprecated.",
360 gp->name);
361 }
362 return (gp);
363 }
364 g_detach(cp);
365 g_destroy_consumer(cp);
366 g_destroy_geom(gp);
367 return (NULL);
368 }
369
370 static struct g_class g_aes_class = {
371 .name = AES_CLASS_NAME,
372 .version = G_VERSION,
373 .taste = g_aes_taste,
374 .start = g_aes_start,
375 .orphan = g_aes_orphan,
376 .spoiled = g_std_spoiled,
377 .access = g_aes_access,
378 };
379
380 DECLARE_GEOM_CLASS(g_aes_class, g_aes);
381