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
66static const u_char *aes_magic = "<<FreeBSD-GEOM-AES>>";
67static const u_char *aes_magic_random = "<<FreeBSD-GEOM-AES-RANDOM>>";
68static const u_char *aes_magic_test = "<<FreeBSD-GEOM-AES-TEST>>";
69
70
71struct 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
97static void
98g_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
133static void
134g_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
161static void
162g_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
170static void
171g_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
236static void
237g_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
245	gp = cp->geom;
246	sc = gp->softc;
247	g_wither_geom(gp, ENXIO);
248	bzero(sc, sizeof(struct g_aes_softc));	/* destroy evidence */
249	g_free(sc);
250	return;
251}
252
253static int
254g_aes_access(struct g_provider *pp, int dr, int dw, int de)
255{
256	struct g_geom *gp;
257	struct g_consumer *cp;
258
259	gp = pp->geom;
260	cp = LIST_FIRST(&gp->consumer);
261	/* On first open, grab an extra "exclusive" bit */
262	if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0)
263		de++;
264	/* ... and let go of it on last close */
265	if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1)
266		de--;
267	return (g_access(cp, dr, dw, de));
268}
269
270static struct g_geom *
271g_aes_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
272{
273	struct g_geom *gp;
274	struct g_consumer *cp;
275	struct g_aes_softc *sc;
276	int error;
277	u_int sectorsize;
278	off_t mediasize;
279	u_char *buf;
280
281	g_trace(G_T_TOPOLOGY, "aes_taste(%s,%s)", mp->name, pp->name);
282	g_topology_assert();
283	gp = g_new_geomf(mp, "%s.aes", pp->name);
284	cp = g_new_consumer(gp);
285	g_attach(cp, pp);
286	error = g_access(cp, 1, 0, 0);
287	if (error) {
288		g_detach(cp);
289		g_destroy_consumer(cp);
290		g_destroy_geom(gp);
291		return (NULL);
292	}
293	buf = NULL;
294	g_topology_unlock();
295	do {
296		if (gp->rank != 2)
297			break;
298		sectorsize = cp->provider->sectorsize;
299		mediasize = cp->provider->mediasize;
300		buf = g_read_data(cp, 0, sectorsize, NULL);
301		if (buf == NULL) {
302			break;
303		}
304		sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO);
305		if (!memcmp(buf, aes_magic, strlen(aes_magic))) {
306			sc->keying = KEY_ZERO;
307		} else if (!memcmp(buf, aes_magic_random,
308		    strlen(aes_magic_random))) {
309			sc->keying = KEY_RANDOM;
310		} else if (!memcmp(buf, aes_magic_test,
311		    strlen(aes_magic_test))) {
312			sc->keying = KEY_TEST;
313		} else {
314			g_free(sc);
315			break;
316		}
317		g_free(buf);
318		gp->softc = sc;
319		sc->sectorsize = sectorsize;
320		sc->mediasize = mediasize - sectorsize;
321		rijndael_cipherInit(&sc->ci, MODE_CBC, NULL);
322		if (sc->keying == KEY_TEST) {
323			int i;
324			u_char *p;
325
326			p = sc->master_key;
327			for (i = 0; i < (int)sizeof sc->master_key; i ++)
328				*p++ = i;
329		}
330		if (sc->keying == KEY_RANDOM) {
331			int i;
332			u_int32_t u;
333			u_char *p;
334
335			p = sc->master_key;
336			for (i = 0; i < (int)sizeof sc->master_key; i += sizeof u) {
337				u = arc4random();
338				*p++ = u;
339				*p++ = u >> 8;
340				*p++ = u >> 16;
341				*p++ = u >> 24;
342			}
343		}
344		g_topology_lock();
345		pp = g_new_providerf(gp, "%s", gp->name);
346		pp->mediasize = mediasize - sectorsize;
347		pp->sectorsize = sectorsize;
348		g_error_provider(pp, 0);
349		g_topology_unlock();
350	} while(0);
351	g_topology_lock();
352	if (buf)
353		g_free(buf);
354	g_access(cp, -1, 0, 0);
355	if (gp->softc != NULL)
356		return (gp);
357	g_detach(cp);
358	g_destroy_consumer(cp);
359	g_destroy_geom(gp);
360	return (NULL);
361}
362
363static struct g_class g_aes_class	= {
364	.name = AES_CLASS_NAME,
365	.version = G_VERSION,
366	.taste = g_aes_taste,
367	.start = g_aes_start,
368	.orphan = g_aes_orphan,
369	.spoiled = g_std_spoiled,
370	.access = g_aes_access,
371};
372
373DECLARE_GEOM_CLASS(g_aes_class, g_aes);
374