geom_aes.c revision 152971
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: head/sys/geom/geom_aes.c 152971 2005-11-30 22:15:00Z sobomax $"); 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 KASSERT(cp->provider->error != 0, 245 ("g_aes_orphan with error == 0")); 246 247 gp = cp->geom; 248 sc = gp->softc; 249 g_wither_geom(gp, cp->provider->error); 250 bzero(sc, sizeof(struct g_aes_softc)); /* destroy evidence */ 251 g_free(sc); 252 return; 253} 254 255static int 256g_aes_access(struct g_provider *pp, int dr, int dw, int de) 257{ 258 struct g_geom *gp; 259 struct g_consumer *cp; 260 261 gp = pp->geom; 262 cp = LIST_FIRST(&gp->consumer); 263 /* On first open, grab an extra "exclusive" bit */ 264 if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0) 265 de++; 266 /* ... and let go of it on last close */ 267 if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1) 268 de--; 269 return (g_access(cp, dr, dw, de)); 270} 271 272static struct g_geom * 273g_aes_taste(struct g_class *mp, struct g_provider *pp, int flags __unused) 274{ 275 struct g_geom *gp; 276 struct g_consumer *cp; 277 struct g_aes_softc *sc; 278 int error; 279 u_int sectorsize; 280 off_t mediasize; 281 u_char *buf; 282 283 g_trace(G_T_TOPOLOGY, "aes_taste(%s,%s)", mp->name, pp->name); 284 g_topology_assert(); 285 gp = g_new_geomf(mp, "%s.aes", pp->name); 286 cp = g_new_consumer(gp); 287 g_attach(cp, pp); 288 error = g_access(cp, 1, 0, 0); 289 if (error) { 290 g_detach(cp); 291 g_destroy_consumer(cp); 292 g_destroy_geom(gp); 293 return (NULL); 294 } 295 buf = NULL; 296 g_topology_unlock(); 297 do { 298 if (gp->rank != 2) 299 break; 300 sectorsize = cp->provider->sectorsize; 301 mediasize = cp->provider->mediasize; 302 buf = g_read_data(cp, 0, sectorsize, NULL); 303 if (buf == NULL) { 304 break; 305 } 306 sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO); 307 if (!memcmp(buf, aes_magic, strlen(aes_magic))) { 308 sc->keying = KEY_ZERO; 309 } else if (!memcmp(buf, aes_magic_random, 310 strlen(aes_magic_random))) { 311 sc->keying = KEY_RANDOM; 312 } else if (!memcmp(buf, aes_magic_test, 313 strlen(aes_magic_test))) { 314 sc->keying = KEY_TEST; 315 } else { 316 g_free(sc); 317 break; 318 } 319 g_free(buf); 320 gp->softc = sc; 321 sc->sectorsize = sectorsize; 322 sc->mediasize = mediasize - sectorsize; 323 rijndael_cipherInit(&sc->ci, MODE_CBC, NULL); 324 if (sc->keying == KEY_TEST) { 325 int i; 326 u_char *p; 327 328 p = sc->master_key; 329 for (i = 0; i < (int)sizeof sc->master_key; i ++) 330 *p++ = i; 331 } 332 if (sc->keying == KEY_RANDOM) { 333 int i; 334 u_int32_t u; 335 u_char *p; 336 337 p = sc->master_key; 338 for (i = 0; i < (int)sizeof sc->master_key; i += sizeof u) { 339 u = arc4random(); 340 *p++ = u; 341 *p++ = u >> 8; 342 *p++ = u >> 16; 343 *p++ = u >> 24; 344 } 345 } 346 g_topology_lock(); 347 pp = g_new_providerf(gp, gp->name); 348 pp->mediasize = mediasize - sectorsize; 349 pp->sectorsize = sectorsize; 350 g_error_provider(pp, 0); 351 g_topology_unlock(); 352 } while(0); 353 g_topology_lock(); 354 if (buf) 355 g_free(buf); 356 g_access(cp, -1, 0, 0); 357 if (gp->softc != NULL) 358 return (gp); 359 g_detach(cp); 360 g_destroy_consumer(cp); 361 g_destroy_geom(gp); 362 return (NULL); 363} 364 365static struct g_class g_aes_class = { 366 .name = AES_CLASS_NAME, 367 .version = G_VERSION, 368 .taste = g_aes_taste, 369 .start = g_aes_start, 370 .orphan = g_aes_orphan, 371 .spoiled = g_std_spoiled, 372 .access = g_aes_access, 373}; 374 375DECLARE_GEOM_CLASS(g_aes_class, g_aes); 376