geom_aes.c revision 113032
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: head/sys/geom/geom_aes.c 113032 2003-04-03 19:19:36Z 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#ifndef _KERNEL 45#include <stdio.h> 46#include <string.h> 47#include <stdlib.h> 48#include <signal.h> 49#include <err.h> 50#else 51#include <sys/systm.h> 52#include <sys/kernel.h> 53#include <sys/conf.h> 54#include <sys/bio.h> 55#include <sys/malloc.h> 56#include <sys/lock.h> 57#include <sys/mutex.h> 58#include <sys/libkern.h> 59#endif 60#include <sys/endian.h> 61#include <sys/md5.h> 62#include <sys/errno.h> 63#include <geom/geom.h> 64 65#include <crypto/rijndael/rijndael.h> 66 67#include <crypto/rijndael/rijndael.h> 68 69#define AES_CLASS_NAME "AES" 70 71#define MASTER_KEY_LENGTH (1024/8) 72 73static const u_char *aes_magic = "<<FreeBSD-GEOM-AES>>"; 74static const u_char *aes_magic_random = "<<FreeBSD-GEOM-AES-RANDOM>>"; 75static const u_char *aes_magic_test = "<<FreeBSD-GEOM-AES-TEST>>"; 76 77 78struct g_aes_softc { 79 enum { 80 KEY_ZERO, 81 KEY_RANDOM, 82 KEY_TEST 83 } keying; 84 u_int sectorsize; 85 off_t mediasize; 86 cipherInstance ci; 87 u_char master_key[MASTER_KEY_LENGTH]; 88}; 89 90/* 91 * Generate a sectorkey from the masterkey and the offset position. 92 * 93 * For KEY_ZERO we just return a key of all zeros. 94 * 95 * We feed the sector byte offset, 16 bytes of the master-key and 96 * the sector byte offset once more to MD5. 97 * The sector byte offset is converted to little-endian format first 98 * to support multi-architecture operation. 99 * We use 16 bytes from the master-key starting at the logical sector 100 * number modulus he length of the master-key. If need be we wrap 101 * around to the start of the master-key. 102 */ 103 104static void 105g_aes_makekey(struct g_aes_softc *sc, off_t off, keyInstance *ki, int dir) 106{ 107 MD5_CTX cx; 108 u_int64_t u64; 109 u_int u, u1; 110 u_char *p, buf[16]; 111 112 if (sc->keying == KEY_ZERO) { 113 rijndael_makeKey(ki, dir, 128, sc->master_key); 114 return; 115 } 116 MD5Init(&cx); 117 u64 = htole64(off); 118 MD5Update(&cx, (u_char *)&u64, sizeof(u64)); 119 u = off / sc->sectorsize; 120 u %= sizeof sc->master_key; 121 p = sc->master_key + u; 122 if (u + 16 <= sizeof(sc->master_key)) { 123 MD5Update(&cx, p, 16); 124 } else { 125 u1 = sizeof sc->master_key - u; 126 MD5Update(&cx, p, u1); 127 MD5Update(&cx, sc->master_key, 16 - u1); 128 u1 = 0; /* destroy evidence */ 129 } 130 u = 0; /* destroy evidence */ 131 MD5Update(&cx, (u_char *)&u64, sizeof(u64)); 132 u64 = 0; /* destroy evidence */ 133 MD5Final(buf, &cx); 134 bzero(&cx, sizeof cx); /* destroy evidence */ 135 rijndael_makeKey(ki, dir, 128, buf); 136 bzero(buf, sizeof buf); /* destroy evidence */ 137 138} 139 140static void 141g_aes_read_done(struct bio *bp) 142{ 143 struct g_geom *gp; 144 struct g_aes_softc *sc; 145 u_char *p, *b, *e, *sb; 146 keyInstance dkey; 147 off_t o; 148 149 gp = bp->bio_from->geom; 150 sc = gp->softc; 151 sb = g_malloc(sc->sectorsize, M_WAITOK); 152 b = bp->bio_data; 153 e = bp->bio_data; 154 e += bp->bio_length; 155 o = bp->bio_offset - sc->sectorsize; 156 for (p = b; p < e; p += sc->sectorsize) { 157 g_aes_makekey(sc, o, &dkey, DIR_DECRYPT); 158 rijndael_blockDecrypt(&sc->ci, &dkey, p, sc->sectorsize * 8, sb); 159 bcopy(sb, p, sc->sectorsize); 160 o += sc->sectorsize; 161 } 162 bzero(&dkey, sizeof dkey); /* destroy evidence */ 163 bzero(sb, sc->sectorsize); /* destroy evidence */ 164 g_free(sb); 165 g_std_done(bp); 166} 167 168static void 169g_aes_write_done(struct bio *bp) 170{ 171 struct g_aes_softc *sc; 172 struct g_geom *gp; 173 174 gp = bp->bio_to->geom; 175 sc = gp->softc; 176 bzero(bp->bio_data, bp->bio_length); /* destroy evidence */ 177 g_free(bp->bio_data); 178 g_std_done(bp); 179} 180 181static void 182g_aes_start(struct bio *bp) 183{ 184 struct g_geom *gp; 185 struct g_consumer *cp; 186 struct g_aes_softc *sc; 187 struct bio *bp2; 188 u_char *p1, *p2, *b, *e; 189 keyInstance ekey; 190 off_t o; 191 192 gp = bp->bio_to->geom; 193 cp = LIST_FIRST(&gp->consumer); 194 sc = gp->softc; 195 switch (bp->bio_cmd) { 196 case BIO_READ: 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_read_done; 203 bp2->bio_offset += sc->sectorsize; 204 g_io_request(bp2, cp); 205 break; 206 case BIO_WRITE: 207 bp2 = g_clone_bio(bp); 208 if (bp2 == NULL) { 209 g_io_deliver(bp, ENOMEM); 210 return; 211 } 212 bp2->bio_done = g_aes_write_done; 213 bp2->bio_offset += sc->sectorsize; 214 bp2->bio_data = g_malloc(bp->bio_length, M_WAITOK); 215 b = bp->bio_data; 216 e = bp->bio_data; 217 e += bp->bio_length; 218 p2 = bp2->bio_data; 219 o = bp->bio_offset; 220 for (p1 = b; p1 < e; p1 += sc->sectorsize) { 221 g_aes_makekey(sc, o, &ekey, DIR_ENCRYPT); 222 rijndael_blockEncrypt(&sc->ci, &ekey, 223 p1, sc->sectorsize * 8, p2); 224 p2 += sc->sectorsize; 225 o += sc->sectorsize; 226 } 227 bzero(&ekey, sizeof ekey); /* destroy evidence */ 228 g_io_request(bp2, cp); 229 break; 230 case BIO_GETATTR: 231 bp2 = g_clone_bio(bp); 232 if (bp2 == NULL) { 233 g_io_deliver(bp, ENOMEM); 234 return; 235 } 236 bp2->bio_done = g_std_done; 237 bp2->bio_offset += sc->sectorsize; 238 g_io_request(bp2, cp); 239 break; 240 default: 241 g_io_deliver(bp, EOPNOTSUPP); 242 return; 243 } 244 return; 245} 246 247static void 248g_aes_orphan(struct g_consumer *cp) 249{ 250 struct g_geom *gp; 251 struct g_provider *pp; 252 struct g_aes_softc *sc; 253 int error; 254 255 g_trace(G_T_TOPOLOGY, "g_aes_orphan(%p/%s)", cp, cp->provider->name); 256 g_topology_assert(); 257 KASSERT(cp->provider->error != 0, 258 ("g_aes_orphan with error == 0")); 259 260 gp = cp->geom; 261 sc = gp->softc; 262 gp->flags |= G_GEOM_WITHER; 263 error = cp->provider->error; 264 LIST_FOREACH(pp, &gp->provider, provider) 265 g_orphan_provider(pp, error); 266 bzero(sc, sizeof(struct g_aes_softc)); /* destroy evidence */ 267 return; 268} 269 270static int 271g_aes_access(struct g_provider *pp, int dr, int dw, int de) 272{ 273 struct g_geom *gp; 274 struct g_consumer *cp; 275 276 gp = pp->geom; 277 cp = LIST_FIRST(&gp->consumer); 278 /* On first open, grab an extra "exclusive" bit */ 279 if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0) 280 de++; 281 /* ... and let go of it on last close */ 282 if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1) 283 de--; 284 return (g_access_rel(cp, dr, dw, de)); 285} 286 287static struct g_geom * 288g_aes_taste(struct g_class *mp, struct g_provider *pp, int flags __unused) 289{ 290 struct g_geom *gp; 291 struct g_consumer *cp; 292 struct g_aes_softc *sc; 293 int error; 294 u_int sectorsize; 295 off_t mediasize; 296 u_char *buf; 297 298 g_trace(G_T_TOPOLOGY, "aes_taste(%s,%s)", mp->name, pp->name); 299 g_topology_assert(); 300 gp = g_new_geomf(mp, "%s.aes", pp->name); 301 gp->start = g_aes_start; 302 gp->orphan = g_aes_orphan; 303 gp->spoiled = g_std_spoiled; 304 cp = g_new_consumer(gp); 305 g_attach(cp, pp); 306 error = g_access_rel(cp, 1, 0, 0); 307 if (error) { 308 g_detach(cp); 309 g_destroy_consumer(cp); 310 g_destroy_geom(gp); 311 return (NULL); 312 } 313 buf = NULL; 314 g_topology_unlock(); 315 while (1) { 316 if (gp->rank != 2) 317 break; 318 sectorsize = cp->provider->sectorsize; 319 mediasize = cp->provider->mediasize; 320 buf = g_read_data(cp, 0, sectorsize, &error); 321 if (buf == NULL || error != 0) { 322 break; 323 } 324 sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO); 325 if (!memcmp(buf, aes_magic, strlen(aes_magic))) { 326 sc->keying = KEY_ZERO; 327 } else if (!memcmp(buf, aes_magic_random, 328 strlen(aes_magic_random))) { 329 sc->keying = KEY_RANDOM; 330 } else if (!memcmp(buf, aes_magic_test, 331 strlen(aes_magic_test))) { 332 sc->keying = KEY_TEST; 333 } else { 334 g_free(sc); 335 break; 336 } 337 gp->softc = sc; 338 gp->access = g_aes_access; 339 sc->sectorsize = sectorsize; 340 sc->mediasize = mediasize - sectorsize; 341 rijndael_cipherInit(&sc->ci, MODE_CBC, NULL); 342 if (sc->keying == KEY_TEST) { 343 int i; 344 u_char *p; 345 346 p = sc->master_key; 347 for (i = 0; i < (int)sizeof sc->master_key; i ++) 348 *p++ = i; 349 } 350 if (sc->keying == KEY_RANDOM) { 351 int i; 352 u_int32_t u; 353 u_char *p; 354 355 p = sc->master_key; 356 for (i = 0; i < (int)sizeof sc->master_key; i += sizeof u) { 357 u = arc4random(); 358 *p++ = u; 359 *p++ = u >> 8; 360 *p++ = u >> 16; 361 *p++ = u >> 24; 362 } 363 } 364 g_topology_lock(); 365 pp = g_new_providerf(gp, gp->name); 366 pp->mediasize = mediasize - sectorsize; 367 pp->sectorsize = sectorsize; 368 g_error_provider(pp, 0); 369 g_topology_unlock(); 370 break; 371 } 372 g_topology_lock(); 373 if (buf) 374 g_free(buf); 375 g_access_rel(cp, -1, 0, 0); 376 if (gp->softc != NULL) 377 return (gp); 378 g_detach(cp); 379 g_destroy_consumer(cp); 380 g_destroy_geom(gp); 381 return (NULL); 382} 383 384static struct g_class g_aes_class = { 385 .name = AES_CLASS_NAME, 386 .taste = g_aes_taste, 387 G_CLASS_INITIALIZER 388}; 389 390DECLARE_GEOM_CLASS(g_aes_class, g_aes); 391