1 /*- 2 * Copyright (c) 2005-2011 Pawel Jakub Dawidek <pawel@dawidek.net> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/kernel.h> 33 #include <sys/linker.h> 34 #include <sys/module.h> 35 #include <sys/lock.h> 36 #include <sys/mutex.h> 37 #include <sys/bio.h> 38 #include <sys/sysctl.h> 39 #include <sys/malloc.h> 40 #include <sys/kthread.h> 41 #include <sys/proc.h> 42 #include <sys/sched.h> 43 #include <sys/smp.h> 44 #include <sys/vnode.h> 45 46 #include <vm/uma.h> 47 48 #include <geom/geom.h> 49 #include <geom/eli/g_eli.h> 50 #include <geom/eli/pkcs5v2.h> 51 52 /* 53 * The data layout description when integrity verification is configured. 54 * 55 * One of the most important assumption here is that authenticated data and its 56 * HMAC has to be stored in the same place (namely in the same sector) to make 57 * it work reliable. 58 * The problem is that file systems work only with sectors that are multiple of 59 * 512 bytes and a power of two number. 60 * My idea to implement it is as follows. 61 * Let's store HMAC in sector. This is a must. This leaves us 480 bytes for 62 * data. We can't use that directly (ie. we can't create provider with 480 bytes 63 * sector size). We need another sector from where we take only 32 bytes of data 64 * and we store HMAC of this data as well. This takes two sectors from the 65 * original provider at the input and leaves us one sector of authenticated data 66 * at the output. Not very efficient, but you got the idea. 67 * Now, let's assume, we want to create provider with 4096 bytes sector. 68 * To output 4096 bytes of authenticated data we need 8x480 plus 1x256, so we 69 * need nine 512-bytes sectors at the input to get one 4096-bytes sector at the 70 * output. That's better. With 4096 bytes sector we can use 89% of size of the 71 * original provider. I find it as an acceptable cost. 72 * The reliability comes from the fact, that every HMAC stored inside the sector 73 * is calculated only for the data in the same sector, so its impossible to 74 * write new data and leave old HMAC or vice versa. 75 * 76 * And here is the picture: 77 * 78 * da0: +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+-----+ 79 * |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |256b | 80 * |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data | 81 * +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+-----+ 82 * |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |288 bytes | 83 * +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ |224 unused| 84 * +----------+ 85 * da0.eli: +----+----+----+----+----+----+----+----+----+ 86 * |480b|480b|480b|480b|480b|480b|480b|480b|256b| 87 * +----+----+----+----+----+----+----+----+----+ 88 * | 4096 bytes | 89 * +--------------------------------------------+ 90 * 91 * PS. You can use any sector size with geli(8). My example is using 4kB, 92 * because it's most efficient. For 8kB sectors you need 2 extra sectors, 93 * so the cost is the same as for 4kB sectors. 94 */ 95 96 /* 97 * Code paths: 98 * BIO_READ: 99 * g_eli_start -> g_eli_auth_read -> g_io_request -> g_eli_read_done -> g_eli_auth_run -> g_eli_auth_read_done -> g_io_deliver 100 * BIO_WRITE: 101 * g_eli_start -> g_eli_auth_run -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver 102 */ 103 104 MALLOC_DECLARE(M_ELI); 105 106 /* 107 * Here we generate key for HMAC. Every sector has its own HMAC key, so it is 108 * not possible to copy sectors. 109 * We cannot depend on fact, that every sector has its own IV, because different 110 * IV doesn't change HMAC, when we use encrypt-then-authenticate method. 111 */ 112 static void 113 g_eli_auth_keygen(struct g_eli_softc *sc, off_t offset, u_char *key) 114 { 115 SHA256_CTX ctx; 116 117 /* Copy precalculated SHA256 context. */ 118 bcopy(&sc->sc_akeyctx, &ctx, sizeof(ctx)); 119 SHA256_Update(&ctx, (uint8_t *)&offset, sizeof(offset)); 120 SHA256_Final(key, &ctx); 121 } 122 123 /* 124 * The function is called after we read and decrypt data. 125 * 126 * g_eli_start -> g_eli_auth_read -> g_io_request -> g_eli_read_done -> g_eli_auth_run -> G_ELI_AUTH_READ_DONE -> g_io_deliver 127 */ 128 static int 129 g_eli_auth_read_done(struct cryptop *crp) 130 { 131 struct g_eli_softc *sc; 132 struct bio *bp; 133 134 if (crp->crp_etype == EAGAIN) { 135 if (g_eli_crypto_rerun(crp) == 0) 136 return (0); 137 } 138 bp = (struct bio *)crp->crp_opaque; 139 bp->bio_inbed++; 140 if (crp->crp_etype == 0) { 141 bp->bio_completed += crp->crp_olen; 142 G_ELI_DEBUG(3, "Crypto READ request done (%d/%d) (add=%jd completed=%jd).", 143 bp->bio_inbed, bp->bio_children, (intmax_t)crp->crp_olen, (intmax_t)bp->bio_completed); 144 } else { 145 G_ELI_DEBUG(1, "Crypto READ request failed (%d/%d) error=%d.", 146 bp->bio_inbed, bp->bio_children, crp->crp_etype); 147 if (bp->bio_error == 0) 148 bp->bio_error = crp->crp_etype; 149 } 150 sc = bp->bio_to->geom->softc; 151 g_eli_key_drop(sc, crp->crp_desc->crd_next->crd_key); 152 /* 153 * Do we have all sectors already? 154 */ 155 if (bp->bio_inbed < bp->bio_children) 156 return (0); 157 if (bp->bio_error == 0) { 158 u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize; 159 u_char *srcdata, *dstdata, *auth; 160 off_t coroff, corsize; 161 162 /* 163 * Verify data integrity based on calculated and read HMACs. 164 */ 165 /* Sectorsize of decrypted provider eg. 4096. */ 166 decr_secsize = bp->bio_to->sectorsize; 167 /* The real sectorsize of encrypted provider, eg. 512. */ 168 encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize; 169 /* Number of data bytes in one encrypted sector, eg. 480. */ 170 data_secsize = sc->sc_data_per_sector; 171 /* Number of sectors from decrypted provider, eg. 2. */ 172 nsec = bp->bio_length / decr_secsize; 173 /* Number of sectors from encrypted provider, eg. 18. */ 174 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize; 175 /* Last sector number in every big sector, eg. 9. */ 176 lsec = sc->sc_bytes_per_sector / encr_secsize; 177 178 srcdata = bp->bio_driver2; 179 dstdata = bp->bio_data; 180 auth = srcdata + encr_secsize * nsec; 181 coroff = -1; 182 corsize = 0; 183 184 for (i = 1; i <= nsec; i++) { 185 data_secsize = sc->sc_data_per_sector; 186 if ((i % lsec) == 0) 187 data_secsize = decr_secsize % data_secsize; 188 if (bcmp(srcdata, auth, sc->sc_alen) != 0) { 189 /* 190 * Curruption detected, remember the offset if 191 * this is the first corrupted sector and 192 * increase size. 193 */ 194 if (bp->bio_error == 0) 195 bp->bio_error = -1; 196 if (coroff == -1) { 197 coroff = bp->bio_offset + 198 (dstdata - (u_char *)bp->bio_data); 199 } 200 corsize += data_secsize; 201 } else { 202 /* 203 * No curruption, good. 204 * Report previous corruption if there was one. 205 */ 206 if (coroff != -1) { 207 G_ELI_DEBUG(0, "%s: Failed to authenticate %jd " 208 "bytes of data at offset %jd.", 209 sc->sc_name, (intmax_t)corsize, 210 (intmax_t)coroff); 211 coroff = -1; 212 corsize = 0; 213 } 214 bcopy(srcdata + sc->sc_alen, dstdata, 215 data_secsize); 216 } 217 srcdata += encr_secsize; 218 dstdata += data_secsize; 219 auth += sc->sc_alen; 220 } 221 /* Report previous corruption if there was one. */ 222 if (coroff != -1) { 223 G_ELI_DEBUG(0, "%s: Failed to authenticate %jd " 224 "bytes of data at offset %jd.", 225 sc->sc_name, (intmax_t)corsize, (intmax_t)coroff); 226 } 227 } 228 free(bp->bio_driver2, M_ELI); 229 bp->bio_driver2 = NULL; 230 if (bp->bio_error != 0) { 231 if (bp->bio_error == -1) 232 bp->bio_error = EINVAL; 233 else { 234 G_ELI_LOGREQ(0, bp, 235 "Crypto READ request failed (error=%d).", 236 bp->bio_error); 237 } 238 bp->bio_completed = 0; 239 } 240 /* 241 * Read is finished, send it up. 242 */ 243 g_io_deliver(bp, bp->bio_error); 244 atomic_subtract_int(&sc->sc_inflight, 1); 245 return (0); 246 } 247 248 /* 249 * The function is called after data encryption. 250 * 251 * g_eli_start -> g_eli_auth_run -> G_ELI_AUTH_WRITE_DONE -> g_io_request -> g_eli_write_done -> g_io_deliver 252 */ 253 static int 254 g_eli_auth_write_done(struct cryptop *crp) 255 { 256 struct g_eli_softc *sc; 257 struct g_consumer *cp; 258 struct bio *bp, *cbp, *cbp2; 259 u_int nsec; 260 261 if (crp->crp_etype == EAGAIN) { 262 if (g_eli_crypto_rerun(crp) == 0) 263 return (0); 264 } 265 bp = (struct bio *)crp->crp_opaque; 266 bp->bio_inbed++; 267 if (crp->crp_etype == 0) { 268 G_ELI_DEBUG(3, "Crypto WRITE request done (%d/%d).", 269 bp->bio_inbed, bp->bio_children); 270 } else { 271 G_ELI_DEBUG(1, "Crypto WRITE request failed (%d/%d) error=%d.", 272 bp->bio_inbed, bp->bio_children, crp->crp_etype); 273 if (bp->bio_error == 0) 274 bp->bio_error = crp->crp_etype; 275 } 276 sc = bp->bio_to->geom->softc; 277 g_eli_key_drop(sc, crp->crp_desc->crd_key); 278 /* 279 * All sectors are already encrypted? 280 */ 281 if (bp->bio_inbed < bp->bio_children) 282 return (0); 283 if (bp->bio_error != 0) { 284 G_ELI_LOGREQ(0, bp, "Crypto WRITE request failed (error=%d).", 285 bp->bio_error); 286 free(bp->bio_driver2, M_ELI); 287 bp->bio_driver2 = NULL; 288 cbp = bp->bio_driver1; 289 bp->bio_driver1 = NULL; 290 g_destroy_bio(cbp); 291 g_io_deliver(bp, bp->bio_error); 292 atomic_subtract_int(&sc->sc_inflight, 1); 293 return (0); 294 } 295 cp = LIST_FIRST(&sc->sc_geom->consumer); 296 cbp = bp->bio_driver1; 297 bp->bio_driver1 = NULL; 298 cbp->bio_to = cp->provider; 299 cbp->bio_done = g_eli_write_done; 300 301 /* Number of sectors from decrypted provider, eg. 1. */ 302 nsec = bp->bio_length / bp->bio_to->sectorsize; 303 /* Number of sectors from encrypted provider, eg. 9. */ 304 nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize; 305 306 cbp->bio_length = cp->provider->sectorsize * nsec; 307 cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector; 308 cbp->bio_data = bp->bio_driver2; 309 310 /* 311 * We write more than what is requested, so we have to be ready to write 312 * more than MAXPHYS. 313 */ 314 cbp2 = NULL; 315 if (cbp->bio_length > MAXPHYS) { 316 cbp2 = g_duplicate_bio(bp); 317 cbp2->bio_length = cbp->bio_length - MAXPHYS; 318 cbp2->bio_data = cbp->bio_data + MAXPHYS; 319 cbp2->bio_offset = cbp->bio_offset + MAXPHYS; 320 cbp2->bio_to = cp->provider; 321 cbp2->bio_done = g_eli_write_done; 322 cbp->bio_length = MAXPHYS; 323 } 324 /* 325 * Send encrypted data to the provider. 326 */ 327 G_ELI_LOGREQ(2, cbp, "Sending request."); 328 bp->bio_inbed = 0; 329 bp->bio_children = (cbp2 != NULL ? 2 : 1); 330 g_io_request(cbp, cp); 331 if (cbp2 != NULL) { 332 G_ELI_LOGREQ(2, cbp2, "Sending request."); 333 g_io_request(cbp2, cp); 334 } 335 return (0); 336 } 337 338 void 339 g_eli_auth_read(struct g_eli_softc *sc, struct bio *bp) 340 { 341 struct g_consumer *cp; 342 struct bio *cbp, *cbp2; 343 size_t size; 344 off_t nsec; 345 346 bp->bio_pflags = 0; 347 348 cp = LIST_FIRST(&sc->sc_geom->consumer); 349 cbp = bp->bio_driver1; 350 bp->bio_driver1 = NULL; 351 cbp->bio_to = cp->provider; 352 cbp->bio_done = g_eli_read_done; 353 354 /* Number of sectors from decrypted provider, eg. 1. */ 355 nsec = bp->bio_length / bp->bio_to->sectorsize; 356 /* Number of sectors from encrypted provider, eg. 9. */ 357 nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize; 358 359 cbp->bio_length = cp->provider->sectorsize * nsec; 360 size = cbp->bio_length; 361 size += sc->sc_alen * nsec; 362 size += sizeof(struct cryptop) * nsec; 363 size += sizeof(struct cryptodesc) * nsec * 2; 364 size += G_ELI_AUTH_SECKEYLEN * nsec; 365 cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector; 366 bp->bio_driver2 = malloc(size, M_ELI, M_WAITOK); 367 cbp->bio_data = bp->bio_driver2; 368 369 /* 370 * We read more than what is requested, so we have to be ready to read 371 * more than MAXPHYS. 372 */ 373 cbp2 = NULL; 374 if (cbp->bio_length > MAXPHYS) { 375 cbp2 = g_duplicate_bio(bp); 376 cbp2->bio_length = cbp->bio_length - MAXPHYS; 377 cbp2->bio_data = cbp->bio_data + MAXPHYS; 378 cbp2->bio_offset = cbp->bio_offset + MAXPHYS; 379 cbp2->bio_to = cp->provider; 380 cbp2->bio_done = g_eli_read_done; 381 cbp->bio_length = MAXPHYS; 382 } 383 /* 384 * Read encrypted data from provider. 385 */ 386 G_ELI_LOGREQ(2, cbp, "Sending request."); 387 g_io_request(cbp, cp); 388 if (cbp2 != NULL) { 389 G_ELI_LOGREQ(2, cbp2, "Sending request."); 390 g_io_request(cbp2, cp); 391 } 392 } 393 394 /* 395 * This is the main function responsible for cryptography (ie. communication 396 * with crypto(9) subsystem). 397 * 398 * BIO_READ: 399 * g_eli_start -> g_eli_auth_read -> g_io_request -> g_eli_read_done -> G_ELI_AUTH_RUN -> g_eli_auth_read_done -> g_io_deliver 400 * BIO_WRITE: 401 * g_eli_start -> G_ELI_AUTH_RUN -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver 402 */ 403 void 404 g_eli_auth_run(struct g_eli_worker *wr, struct bio *bp) 405 { 406 struct g_eli_softc *sc; 407 struct cryptop *crp; 408 struct cryptodesc *crde, *crda; 409 u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize; 410 off_t dstoff; 411 u_char *p, *data, *auth, *authkey, *plaindata; 412 int error; 413 414 G_ELI_LOGREQ(3, bp, "%s", __func__); 415 416 bp->bio_pflags = wr->w_number; 417 sc = wr->w_softc; 418 /* Sectorsize of decrypted provider eg. 4096. */ 419 decr_secsize = bp->bio_to->sectorsize; 420 /* The real sectorsize of encrypted provider, eg. 512. */ 421 encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize; 422 /* Number of data bytes in one encrypted sector, eg. 480. */ 423 data_secsize = sc->sc_data_per_sector; 424 /* Number of sectors from decrypted provider, eg. 2. */ 425 nsec = bp->bio_length / decr_secsize; 426 /* Number of sectors from encrypted provider, eg. 18. */ 427 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize; 428 /* Last sector number in every big sector, eg. 9. */ 429 lsec = sc->sc_bytes_per_sector / encr_secsize; 430 /* Destination offset, used for IV generation. */ 431 dstoff = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector; 432 433 auth = NULL; /* Silence compiler warning. */ 434 plaindata = bp->bio_data; 435 if (bp->bio_cmd == BIO_READ) { 436 data = bp->bio_driver2; 437 auth = data + encr_secsize * nsec; 438 p = auth + sc->sc_alen * nsec; 439 } else { 440 size_t size; 441 442 size = encr_secsize * nsec; 443 size += sizeof(*crp) * nsec; 444 size += sizeof(*crde) * nsec; 445 size += sizeof(*crda) * nsec; 446 size += G_ELI_AUTH_SECKEYLEN * nsec; 447 data = malloc(size, M_ELI, M_WAITOK); 448 bp->bio_driver2 = data; 449 p = data + encr_secsize * nsec; 450 } 451 bp->bio_inbed = 0; 452 bp->bio_children = nsec; 453 454 for (i = 1; i <= nsec; i++, dstoff += encr_secsize) { 455 crp = (struct cryptop *)p; p += sizeof(*crp); 456 crde = (struct cryptodesc *)p; p += sizeof(*crde); 457 crda = (struct cryptodesc *)p; p += sizeof(*crda); 458 authkey = (u_char *)p; p += G_ELI_AUTH_SECKEYLEN; 459 460 data_secsize = sc->sc_data_per_sector; 461 if ((i % lsec) == 0) 462 data_secsize = decr_secsize % data_secsize; 463 464 if (bp->bio_cmd == BIO_READ) { 465 /* Remember read HMAC. */ 466 bcopy(data, auth, sc->sc_alen); 467 auth += sc->sc_alen; 468 /* TODO: bzero(9) can be commented out later. */ 469 bzero(data, sc->sc_alen); 470 } else { 471 bcopy(plaindata, data + sc->sc_alen, data_secsize); 472 plaindata += data_secsize; 473 } 474 475 crp->crp_sid = wr->w_sid; 476 crp->crp_ilen = sc->sc_alen + data_secsize; 477 crp->crp_olen = data_secsize; 478 crp->crp_opaque = (void *)bp; 479 crp->crp_buf = (void *)data; 480 data += encr_secsize; 481 crp->crp_flags = CRYPTO_F_CBIFSYNC; 482 if (g_eli_batch) 483 crp->crp_flags |= CRYPTO_F_BATCH; 484 if (bp->bio_cmd == BIO_WRITE) { 485 crp->crp_callback = g_eli_auth_write_done; 486 crp->crp_desc = crde; 487 crde->crd_next = crda; 488 crda->crd_next = NULL; 489 } else { 490 crp->crp_callback = g_eli_auth_read_done; 491 crp->crp_desc = crda; 492 crda->crd_next = crde; 493 crde->crd_next = NULL; 494 } 495 496 crde->crd_skip = sc->sc_alen; 497 crde->crd_len = data_secsize; 498 crde->crd_flags = CRD_F_IV_EXPLICIT | CRD_F_IV_PRESENT; 499 if ((sc->sc_flags & G_ELI_FLAG_FIRST_KEY) == 0) 500 crde->crd_flags |= CRD_F_KEY_EXPLICIT; 501 if (bp->bio_cmd == BIO_WRITE) 502 crde->crd_flags |= CRD_F_ENCRYPT; 503 crde->crd_alg = sc->sc_ealgo; 504 crde->crd_key = g_eli_key_hold(sc, dstoff, encr_secsize); 505 crde->crd_klen = sc->sc_ekeylen; 506 if (sc->sc_ealgo == CRYPTO_AES_XTS) 507 crde->crd_klen <<= 1; 508 g_eli_crypto_ivgen(sc, dstoff, crde->crd_iv, 509 sizeof(crde->crd_iv)); 510 511 crda->crd_skip = sc->sc_alen; 512 crda->crd_len = data_secsize; 513 crda->crd_inject = 0; 514 crda->crd_flags = CRD_F_KEY_EXPLICIT; 515 crda->crd_alg = sc->sc_aalgo; 516 g_eli_auth_keygen(sc, dstoff, authkey); 517 crda->crd_key = authkey; 518 crda->crd_klen = G_ELI_AUTH_SECKEYLEN * 8; 519 520 crp->crp_etype = 0; 521 error = crypto_dispatch(crp); 522 KASSERT(error == 0, ("crypto_dispatch() failed (error=%d)", 523 error)); 524 } 525 } 526