1 /*- 2 * Copyright (c) 2005-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org> 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/uio.h> 45 #include <sys/vnode.h> 46 47 #include <vm/uma.h> 48 49 #include <geom/geom.h> 50 #include <geom/eli/g_eli.h> 51 #include <geom/eli/pkcs5v2.h> 52 53 /* 54 * The data layout description when integrity verification is configured. 55 * 56 * One of the most important assumption here is that authenticated data and its 57 * HMAC has to be stored in the same place (namely in the same sector) to make 58 * it work reliable. 59 * The problem is that file systems work only with sectors that are multiple of 60 * 512 bytes and a power of two number. 61 * My idea to implement it is as follows. 62 * Let's store HMAC in sector. This is a must. This leaves us 480 bytes for 63 * data. We can't use that directly (ie. we can't create provider with 480 bytes 64 * sector size). We need another sector from where we take only 32 bytes of data 65 * and we store HMAC of this data as well. This takes two sectors from the 66 * original provider at the input and leaves us one sector of authenticated data 67 * at the output. Not very efficient, but you got the idea. 68 * Now, let's assume, we want to create provider with 4096 bytes sector. 69 * To output 4096 bytes of authenticated data we need 8x480 plus 1x256, so we 70 * need nine 512-bytes sectors at the input to get one 4096-bytes sector at the 71 * output. That's better. With 4096 bytes sector we can use 89% of size of the 72 * original provider. I find it as an acceptable cost. 73 * The reliability comes from the fact, that every HMAC stored inside the sector 74 * is calculated only for the data in the same sector, so its impossible to 75 * write new data and leave old HMAC or vice versa. 76 * 77 * And here is the picture: 78 * 79 * da0: +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+-----+ 80 * |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |256b | 81 * |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data | 82 * +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+-----+ 83 * |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |288 bytes | 84 * +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ |224 unused| 85 * +----------+ 86 * da0.eli: +----+----+----+----+----+----+----+----+----+ 87 * |480b|480b|480b|480b|480b|480b|480b|480b|256b| 88 * +----+----+----+----+----+----+----+----+----+ 89 * | 4096 bytes | 90 * +--------------------------------------------+ 91 * 92 * PS. You can use any sector size with geli(8). My example is using 4kB, 93 * because it's most efficient. For 8kB sectors you need 2 extra sectors, 94 * so the cost is the same as for 4kB sectors. 95 */ 96 97 /* 98 * Code paths: 99 * BIO_READ: 100 * 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 101 * BIO_WRITE: 102 * g_eli_start -> g_eli_auth_run -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver 103 */ 104 105 MALLOC_DECLARE(M_ELI); 106 107 /* 108 * Here we generate key for HMAC. Every sector has its own HMAC key, so it is 109 * not possible to copy sectors. 110 * We cannot depend on fact, that every sector has its own IV, because different 111 * IV doesn't change HMAC, when we use encrypt-then-authenticate method. 112 */ 113 static void 114 g_eli_auth_keygen(struct g_eli_softc *sc, off_t offset, u_char *key) 115 { 116 SHA256_CTX ctx; 117 118 /* Copy precalculated SHA256 context. */ 119 bcopy(&sc->sc_akeyctx, &ctx, sizeof(ctx)); 120 SHA256_Update(&ctx, (uint8_t *)&offset, sizeof(offset)); 121 SHA256_Final(key, &ctx); 122 } 123 124 /* 125 * The function is called after we read and decrypt data. 126 * 127 * 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 128 */ 129 static int 130 g_eli_auth_read_done(struct cryptop *crp) 131 { 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 /* 151 * Do we have all sectors already? 152 */ 153 if (bp->bio_inbed < bp->bio_children) 154 return (0); 155 if (bp->bio_error == 0) { 156 struct g_eli_softc *sc; 157 u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize; 158 u_char *srcdata, *dstdata, *auth; 159 off_t coroff, corsize; 160 161 /* 162 * Verify data integrity based on calculated and read HMACs. 163 */ 164 sc = bp->bio_to->geom->softc; 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: %jd bytes " 208 "corrupted 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: %jd bytes corrupted at offset %jd.", 224 sc->sc_name, (intmax_t)corsize, (intmax_t)coroff); 225 } 226 } 227 free(bp->bio_driver2, M_ELI); 228 bp->bio_driver2 = NULL; 229 if (bp->bio_error != 0) { 230 if (bp->bio_error == -1) 231 bp->bio_error = EINVAL; 232 else { 233 G_ELI_LOGREQ(0, bp, 234 "Crypto READ request failed (error=%d).", 235 bp->bio_error); 236 } 237 bp->bio_completed = 0; 238 } 239 /* 240 * Read is finished, send it up. 241 */ 242 g_io_deliver(bp, bp->bio_error); 243 return (0); 244 } 245 246 /* 247 * The function is called after data encryption. 248 * 249 * g_eli_start -> g_eli_auth_run -> G_ELI_AUTH_WRITE_DONE -> g_io_request -> g_eli_write_done -> g_io_deliver 250 */ 251 static int 252 g_eli_auth_write_done(struct cryptop *crp) 253 { 254 struct g_eli_softc *sc; 255 struct g_consumer *cp; 256 struct bio *bp, *cbp, *cbp2; 257 u_int nsec; 258 259 if (crp->crp_etype == EAGAIN) { 260 if (g_eli_crypto_rerun(crp) == 0) 261 return (0); 262 } 263 bp = (struct bio *)crp->crp_opaque; 264 bp->bio_inbed++; 265 if (crp->crp_etype == 0) { 266 G_ELI_DEBUG(3, "Crypto WRITE request done (%d/%d).", 267 bp->bio_inbed, bp->bio_children); 268 } else { 269 G_ELI_DEBUG(1, "Crypto WRITE request failed (%d/%d) error=%d.", 270 bp->bio_inbed, bp->bio_children, crp->crp_etype); 271 if (bp->bio_error == 0) 272 bp->bio_error = crp->crp_etype; 273 } 274 /* 275 * All sectors are already encrypted? 276 */ 277 if (bp->bio_inbed < bp->bio_children) 278 return (0); 279 if (bp->bio_error != 0) { 280 G_ELI_LOGREQ(0, bp, "Crypto WRITE request failed (error=%d).", 281 bp->bio_error); 282 free(bp->bio_driver2, M_ELI); 283 bp->bio_driver2 = NULL; 284 cbp = bp->bio_driver1; 285 bp->bio_driver1 = NULL; 286 g_destroy_bio(cbp); 287 g_io_deliver(bp, bp->bio_error); 288 return (0); 289 } 290 sc = bp->bio_to->geom->softc; 291 cp = LIST_FIRST(&sc->sc_geom->consumer); 292 cbp = bp->bio_driver1; 293 bp->bio_driver1 = NULL; 294 cbp->bio_to = cp->provider; 295 cbp->bio_done = g_eli_write_done; 296 297 /* Number of sectors from decrypted provider, eg. 1. */ 298 nsec = bp->bio_length / bp->bio_to->sectorsize; 299 /* Number of sectors from encrypted provider, eg. 9. */ 300 nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize; 301 302 cbp->bio_length = cp->provider->sectorsize * nsec; 303 cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector; 304 cbp->bio_data = bp->bio_driver2; 305 306 /* 307 * We write more than what is requested, so we have to be ready to write 308 * more than MAXPHYS. 309 */ 310 cbp2 = NULL; 311 if (cbp->bio_length > MAXPHYS) { 312 cbp2 = g_duplicate_bio(bp); 313 cbp2->bio_length = cbp->bio_length - MAXPHYS; 314 cbp2->bio_data = cbp->bio_data + MAXPHYS; 315 cbp2->bio_offset = cbp->bio_offset + MAXPHYS; 316 cbp2->bio_to = cp->provider; 317 cbp2->bio_done = g_eli_write_done; 318 cbp->bio_length = MAXPHYS; 319 } 320 /* 321 * Send encrypted data to the provider. 322 */ 323 G_ELI_LOGREQ(2, cbp, "Sending request."); 324 bp->bio_inbed = 0; 325 bp->bio_children = (cbp2 != NULL ? 2 : 1); 326 g_io_request(cbp, cp); 327 if (cbp2 != NULL) { 328 G_ELI_LOGREQ(2, cbp2, "Sending request."); 329 g_io_request(cbp2, cp); 330 } 331 return (0); 332 } 333 334 void 335 g_eli_auth_read(struct g_eli_softc *sc, struct bio *bp) 336 { 337 struct g_consumer *cp; 338 struct bio *cbp, *cbp2; 339 size_t size; 340 off_t nsec; 341 342 bp->bio_pflags = 0; 343 344 cp = LIST_FIRST(&sc->sc_geom->consumer); 345 cbp = bp->bio_driver1; 346 bp->bio_driver1 = NULL; 347 cbp->bio_to = cp->provider; 348 cbp->bio_done = g_eli_read_done; 349 350 /* Number of sectors from decrypted provider, eg. 1. */ 351 nsec = bp->bio_length / bp->bio_to->sectorsize; 352 /* Number of sectors from encrypted provider, eg. 9. */ 353 nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize; 354 355 cbp->bio_length = cp->provider->sectorsize * nsec; 356 size = cbp->bio_length; 357 size += sc->sc_alen * nsec; 358 size += sizeof(struct cryptop) * nsec; 359 size += sizeof(struct cryptodesc) * nsec * 2; 360 size += G_ELI_AUTH_SECKEYLEN * nsec; 361 size += sizeof(struct uio) * nsec; 362 size += sizeof(struct iovec) * nsec; 363 cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector; 364 bp->bio_driver2 = malloc(size, M_ELI, M_WAITOK); 365 cbp->bio_data = bp->bio_driver2; 366 367 /* 368 * We read more than what is requested, so we have to be ready to read 369 * more than MAXPHYS. 370 */ 371 cbp2 = NULL; 372 if (cbp->bio_length > MAXPHYS) { 373 cbp2 = g_duplicate_bio(bp); 374 cbp2->bio_length = cbp->bio_length - MAXPHYS; 375 cbp2->bio_data = cbp->bio_data + MAXPHYS; 376 cbp2->bio_offset = cbp->bio_offset + MAXPHYS; 377 cbp2->bio_to = cp->provider; 378 cbp2->bio_done = g_eli_read_done; 379 cbp->bio_length = MAXPHYS; 380 } 381 /* 382 * Read encrypted data from provider. 383 */ 384 G_ELI_LOGREQ(2, cbp, "Sending request."); 385 g_io_request(cbp, cp); 386 if (cbp2 != NULL) { 387 G_ELI_LOGREQ(2, cbp2, "Sending request."); 388 g_io_request(cbp2, cp); 389 } 390 } 391 392 /* 393 * This is the main function responsible for cryptography (ie. communication 394 * with crypto(9) subsystem). 395 */ 396 void 397 g_eli_auth_run(struct g_eli_worker *wr, struct bio *bp) 398 { 399 struct g_eli_softc *sc; 400 struct cryptop *crp; 401 struct cryptodesc *crde, *crda; 402 struct uio *uio; 403 struct iovec *iov; 404 u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize; 405 off_t dstoff; 406 int err, error; 407 u_char *p, *data, *auth, *authkey, *plaindata; 408 409 G_ELI_LOGREQ(3, bp, "%s", __func__); 410 411 bp->bio_pflags = wr->w_number; 412 sc = wr->w_softc; 413 /* Sectorsize of decrypted provider eg. 4096. */ 414 decr_secsize = bp->bio_to->sectorsize; 415 /* The real sectorsize of encrypted provider, eg. 512. */ 416 encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize; 417 /* Number of data bytes in one encrypted sector, eg. 480. */ 418 data_secsize = sc->sc_data_per_sector; 419 /* Number of sectors from decrypted provider, eg. 2. */ 420 nsec = bp->bio_length / decr_secsize; 421 /* Number of sectors from encrypted provider, eg. 18. */ 422 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize; 423 /* Last sector number in every big sector, eg. 9. */ 424 lsec = sc->sc_bytes_per_sector / encr_secsize; 425 /* Destination offset, used for IV generation. */ 426 dstoff = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector; 427 428 auth = NULL; /* Silence compiler warning. */ 429 plaindata = bp->bio_data; 430 if (bp->bio_cmd == BIO_READ) { 431 data = bp->bio_driver2; 432 auth = data + encr_secsize * nsec; 433 p = auth + sc->sc_alen * nsec; 434 } else { 435 size_t size; 436 437 size = encr_secsize * nsec; 438 size += sizeof(*crp) * nsec; 439 size += sizeof(*crde) * nsec; 440 size += sizeof(*crda) * nsec; 441 size += G_ELI_AUTH_SECKEYLEN * nsec; 442 size += sizeof(*uio) * nsec; 443 size += sizeof(*iov) * nsec; 444 data = malloc(size, M_ELI, M_WAITOK); 445 bp->bio_driver2 = data; 446 p = data + encr_secsize * nsec; 447 } 448 bp->bio_inbed = 0; 449 bp->bio_children = nsec; 450 451 error = 0; 452 for (i = 1; i <= nsec; i++, dstoff += encr_secsize) { 453 crp = (struct cryptop *)p; p += sizeof(*crp); 454 crde = (struct cryptodesc *)p; p += sizeof(*crde); 455 crda = (struct cryptodesc *)p; p += sizeof(*crda); 456 authkey = (u_char *)p; p += G_ELI_AUTH_SECKEYLEN; 457 uio = (struct uio *)p; p += sizeof(*uio); 458 iov = (struct iovec *)p; p += sizeof(*iov); 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 iov->iov_len = sc->sc_alen + data_secsize; 476 iov->iov_base = data; 477 data += encr_secsize; 478 479 uio->uio_iov = iov; 480 uio->uio_iovcnt = 1; 481 uio->uio_segflg = UIO_SYSSPACE; 482 uio->uio_resid = iov->iov_len; 483 484 crp->crp_sid = wr->w_sid; 485 crp->crp_ilen = uio->uio_resid; 486 crp->crp_olen = data_secsize; 487 crp->crp_opaque = (void *)bp; 488 crp->crp_buf = (void *)uio; 489 crp->crp_flags = CRYPTO_F_IOV | CRYPTO_F_CBIFSYNC | CRYPTO_F_REL; 490 if (g_eli_batch) 491 crp->crp_flags |= CRYPTO_F_BATCH; 492 if (bp->bio_cmd == BIO_WRITE) { 493 crp->crp_callback = g_eli_auth_write_done; 494 crp->crp_desc = crde; 495 crde->crd_next = crda; 496 crda->crd_next = NULL; 497 } else { 498 crp->crp_callback = g_eli_auth_read_done; 499 crp->crp_desc = crda; 500 crda->crd_next = crde; 501 crde->crd_next = NULL; 502 } 503 504 crde->crd_skip = sc->sc_alen; 505 crde->crd_len = data_secsize; 506 crde->crd_flags = CRD_F_IV_EXPLICIT | CRD_F_IV_PRESENT; 507 if (bp->bio_cmd == BIO_WRITE) 508 crde->crd_flags |= CRD_F_ENCRYPT; 509 crde->crd_alg = sc->sc_ealgo; 510 crde->crd_key = sc->sc_ekey; 511 crde->crd_klen = sc->sc_ekeylen; 512 g_eli_crypto_ivgen(sc, dstoff, crde->crd_iv, 513 sizeof(crde->crd_iv)); 514 515 crda->crd_skip = sc->sc_alen; 516 crda->crd_len = data_secsize; 517 crda->crd_inject = 0; 518 crda->crd_flags = CRD_F_KEY_EXPLICIT; 519 crda->crd_alg = sc->sc_aalgo; 520 g_eli_auth_keygen(sc, dstoff, authkey); 521 crda->crd_key = authkey; 522 crda->crd_klen = G_ELI_AUTH_SECKEYLEN * 8; 523 524 crp->crp_etype = 0; 525 err = crypto_dispatch(crp); 526 if (err != 0 && error == 0) 527 error = err; 528 } 529 if (bp->bio_error == 0) 530 bp->bio_error = error; 531 } 532