2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2005-2011 Pawel Jakub Dawidek <pawel@dawidek.net>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/linker.h>
36 #include <sys/module.h>
38 #include <sys/mutex.h>
40 #include <sys/sysctl.h>
41 #include <sys/malloc.h>
42 #include <sys/kthread.h>
44 #include <sys/sched.h>
46 #include <sys/vnode.h>
50 #include <geom/geom.h>
51 #include <geom/geom_dbg.h>
52 #include <geom/eli/g_eli.h>
53 #include <geom/eli/pkcs5v2.h>
56 * The data layout description when integrity verification is configured.
58 * One of the most important assumption here is that authenticated data and its
59 * HMAC has to be stored in the same place (namely in the same sector) to make
61 * The problem is that file systems work only with sectors that are multiple of
62 * 512 bytes and a power of two number.
63 * My idea to implement it is as follows.
64 * Let's store HMAC in sector. This is a must. This leaves us 480 bytes for
65 * data. We can't use that directly (ie. we can't create provider with 480 bytes
66 * sector size). We need another sector from where we take only 32 bytes of data
67 * and we store HMAC of this data as well. This takes two sectors from the
68 * original provider at the input and leaves us one sector of authenticated data
69 * at the output. Not very efficient, but you got the idea.
70 * Now, let's assume, we want to create provider with 4096 bytes sector.
71 * To output 4096 bytes of authenticated data we need 8x480 plus 1x256, so we
72 * need nine 512-bytes sectors at the input to get one 4096-bytes sector at the
73 * output. That's better. With 4096 bytes sector we can use 89% of size of the
74 * original provider. I find it as an acceptable cost.
75 * The reliability comes from the fact, that every HMAC stored inside the sector
76 * is calculated only for the data in the same sector, so its impossible to
77 * write new data and leave old HMAC or vice versa.
79 * And here is the picture:
81 * da0: +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+-----+
82 * |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |256b |
83 * |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data |
84 * +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+-----+
85 * |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |288 bytes |
86 * +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ |224 unused|
88 * da0.eli: +----+----+----+----+----+----+----+----+----+
89 * |480b|480b|480b|480b|480b|480b|480b|480b|256b|
90 * +----+----+----+----+----+----+----+----+----+
92 * +--------------------------------------------+
94 * PS. You can use any sector size with geli(8). My example is using 4kB,
95 * because it's most efficient. For 8kB sectors you need 2 extra sectors,
96 * so the cost is the same as for 4kB sectors.
102 * 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
104 * g_eli_start -> g_eli_auth_run -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver
107 MALLOC_DECLARE(M_ELI);
110 * Here we generate key for HMAC. Every sector has its own HMAC key, so it is
111 * not possible to copy sectors.
112 * We cannot depend on fact, that every sector has its own IV, because different
113 * IV doesn't change HMAC, when we use encrypt-then-authenticate method.
116 g_eli_auth_keygen(struct g_eli_softc *sc, off_t offset, u_char *key)
120 /* Copy precalculated SHA256 context. */
121 bcopy(&sc->sc_akeyctx, &ctx, sizeof(ctx));
122 SHA256_Update(&ctx, (uint8_t *)&offset, sizeof(offset));
123 SHA256_Final(key, &ctx);
127 * The function is called after we read and decrypt data.
129 * 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
132 g_eli_auth_read_done(struct cryptop *crp)
134 struct g_eli_softc *sc;
137 if (crp->crp_etype == EAGAIN) {
138 if (g_eli_crypto_rerun(crp) == 0)
141 bp = (struct bio *)crp->crp_opaque;
143 sc = bp->bio_to->geom->softc;
144 if (crp->crp_etype == 0) {
145 bp->bio_completed += crp->crp_payload_length;
146 G_ELI_DEBUG(3, "Crypto READ request done (%d/%d) (add=%d completed=%jd).",
147 bp->bio_inbed, bp->bio_children, crp->crp_payload_length, (intmax_t)bp->bio_completed);
149 u_int nsec, decr_secsize, encr_secsize, rel_sec;
152 /* Sectorsize of decrypted provider eg. 4096. */
153 decr_secsize = bp->bio_to->sectorsize;
154 /* The real sectorsize of encrypted provider, eg. 512. */
156 LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
157 /* Number of sectors from decrypted provider, eg. 2. */
158 nsec = bp->bio_length / decr_secsize;
159 /* Number of sectors from encrypted provider, eg. 18. */
160 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
161 /* Which relative sector this request decrypted. */
162 rel_sec = ((crp->crp_buf.cb_buf + crp->crp_payload_start) -
163 (char *)bp->bio_driver2) / encr_secsize;
165 errorp = (int *)((char *)bp->bio_driver2 + encr_secsize * nsec +
166 sizeof(int) * rel_sec);
167 *errorp = crp->crp_etype;
169 "Crypto READ request failed (%d/%d) error=%d.",
170 bp->bio_inbed, bp->bio_children, crp->crp_etype);
171 if (bp->bio_error == 0 || bp->bio_error == EINTEGRITY)
172 bp->bio_error = crp->crp_etype == EBADMSG ?
173 EINTEGRITY : crp->crp_etype;
175 if (crp->crp_cipher_key != NULL)
176 g_eli_key_drop(sc, __DECONST(void *, crp->crp_cipher_key));
179 * Do we have all sectors already?
181 if (bp->bio_inbed < bp->bio_children)
184 if (bp->bio_error == 0) {
185 u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
186 u_char *srcdata, *dstdata;
188 /* Sectorsize of decrypted provider eg. 4096. */
189 decr_secsize = bp->bio_to->sectorsize;
190 /* The real sectorsize of encrypted provider, eg. 512. */
191 encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
192 /* Number of data bytes in one encrypted sector, eg. 480. */
193 data_secsize = sc->sc_data_per_sector;
194 /* Number of sectors from decrypted provider, eg. 2. */
195 nsec = bp->bio_length / decr_secsize;
196 /* Number of sectors from encrypted provider, eg. 18. */
197 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
198 /* Last sector number in every big sector, eg. 9. */
199 lsec = sc->sc_bytes_per_sector / encr_secsize;
201 srcdata = bp->bio_driver2;
202 dstdata = bp->bio_data;
204 for (i = 1; i <= nsec; i++) {
205 data_secsize = sc->sc_data_per_sector;
207 data_secsize = decr_secsize % data_secsize;
208 bcopy(srcdata + sc->sc_alen, dstdata, data_secsize);
209 srcdata += encr_secsize;
210 dstdata += data_secsize;
212 } else if (bp->bio_error == EINTEGRITY) {
213 u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
215 off_t coroff, corsize, dstoff;
217 /* Sectorsize of decrypted provider eg. 4096. */
218 decr_secsize = bp->bio_to->sectorsize;
219 /* The real sectorsize of encrypted provider, eg. 512. */
220 encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
221 /* Number of data bytes in one encrypted sector, eg. 480. */
222 data_secsize = sc->sc_data_per_sector;
223 /* Number of sectors from decrypted provider, eg. 2. */
224 nsec = bp->bio_length / decr_secsize;
225 /* Number of sectors from encrypted provider, eg. 18. */
226 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
227 /* Last sector number in every big sector, eg. 9. */
228 lsec = sc->sc_bytes_per_sector / encr_secsize;
230 errorp = (int *)((char *)bp->bio_driver2 + encr_secsize * nsec);
233 dstoff = bp->bio_offset;
235 for (i = 1; i <= nsec; i++) {
236 data_secsize = sc->sc_data_per_sector;
238 data_secsize = decr_secsize % data_secsize;
239 if (errorp[i - 1] == EBADMSG) {
241 * Corruption detected, remember the offset if
242 * this is the first corrupted sector and
247 corsize += data_secsize;
250 * No corruption, good.
251 * Report previous corruption if there was one.
254 G_ELI_DEBUG(0, "%s: Failed to authenticate %jd "
255 "bytes of data at offset %jd.",
256 sc->sc_name, (intmax_t)corsize,
262 dstoff += data_secsize;
264 /* Report previous corruption if there was one. */
266 G_ELI_DEBUG(0, "%s: Failed to authenticate %jd "
267 "bytes of data at offset %jd.",
268 sc->sc_name, (intmax_t)corsize, (intmax_t)coroff);
271 free(bp->bio_driver2, M_ELI);
272 bp->bio_driver2 = NULL;
273 if (bp->bio_error != 0) {
274 if (bp->bio_error != EINTEGRITY) {
276 "Crypto READ request failed (error=%d).",
279 bp->bio_completed = 0;
282 * Read is finished, send it up.
284 g_io_deliver(bp, bp->bio_error);
285 atomic_subtract_int(&sc->sc_inflight, 1);
290 * The function is called after data encryption.
292 * g_eli_start -> g_eli_auth_run -> G_ELI_AUTH_WRITE_DONE -> g_io_request -> g_eli_write_done -> g_io_deliver
295 g_eli_auth_write_done(struct cryptop *crp)
297 struct g_eli_softc *sc;
298 struct g_consumer *cp;
299 struct bio *bp, *cbp, *cbp2;
302 if (crp->crp_etype == EAGAIN) {
303 if (g_eli_crypto_rerun(crp) == 0)
306 bp = (struct bio *)crp->crp_opaque;
308 if (crp->crp_etype == 0) {
309 G_ELI_DEBUG(3, "Crypto WRITE request done (%d/%d).",
310 bp->bio_inbed, bp->bio_children);
312 G_ELI_DEBUG(1, "Crypto WRITE request failed (%d/%d) error=%d.",
313 bp->bio_inbed, bp->bio_children, crp->crp_etype);
314 if (bp->bio_error == 0)
315 bp->bio_error = crp->crp_etype;
317 sc = bp->bio_to->geom->softc;
318 if (crp->crp_cipher_key != NULL)
319 g_eli_key_drop(sc, __DECONST(void *, crp->crp_cipher_key));
322 * All sectors are already encrypted?
324 if (bp->bio_inbed < bp->bio_children)
326 if (bp->bio_error != 0) {
327 G_ELI_LOGREQ(0, bp, "Crypto WRITE request failed (error=%d).",
329 free(bp->bio_driver2, M_ELI);
330 bp->bio_driver2 = NULL;
331 cbp = bp->bio_driver1;
332 bp->bio_driver1 = NULL;
334 g_io_deliver(bp, bp->bio_error);
335 atomic_subtract_int(&sc->sc_inflight, 1);
338 cp = LIST_FIRST(&sc->sc_geom->consumer);
339 cbp = bp->bio_driver1;
340 bp->bio_driver1 = NULL;
341 cbp->bio_to = cp->provider;
342 cbp->bio_done = g_eli_write_done;
344 /* Number of sectors from decrypted provider, eg. 1. */
345 nsec = bp->bio_length / bp->bio_to->sectorsize;
346 /* Number of sectors from encrypted provider, eg. 9. */
347 nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize;
349 cbp->bio_length = cp->provider->sectorsize * nsec;
350 cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
351 cbp->bio_data = bp->bio_driver2;
354 * We write more than what is requested, so we have to be ready to write
358 if (cbp->bio_length > maxphys) {
359 cbp2 = g_duplicate_bio(bp);
360 cbp2->bio_length = cbp->bio_length - maxphys;
361 cbp2->bio_data = cbp->bio_data + maxphys;
362 cbp2->bio_offset = cbp->bio_offset + maxphys;
363 cbp2->bio_to = cp->provider;
364 cbp2->bio_done = g_eli_write_done;
365 cbp->bio_length = maxphys;
368 * Send encrypted data to the provider.
370 G_ELI_LOGREQ(2, cbp, "Sending request.");
372 bp->bio_children = (cbp2 != NULL ? 2 : 1);
373 g_io_request(cbp, cp);
375 G_ELI_LOGREQ(2, cbp2, "Sending request.");
376 g_io_request(cbp2, cp);
382 g_eli_auth_read(struct g_eli_softc *sc, struct bio *bp)
384 struct g_consumer *cp;
385 struct bio *cbp, *cbp2;
391 cp = LIST_FIRST(&sc->sc_geom->consumer);
392 cbp = bp->bio_driver1;
393 bp->bio_driver1 = NULL;
394 cbp->bio_to = cp->provider;
395 cbp->bio_done = g_eli_read_done;
397 /* Number of sectors from decrypted provider, eg. 1. */
398 nsec = bp->bio_length / bp->bio_to->sectorsize;
399 /* Number of sectors from encrypted provider, eg. 9. */
400 nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize;
402 cbp->bio_length = cp->provider->sectorsize * nsec;
403 size = cbp->bio_length;
404 size += sizeof(int) * nsec;
405 size += G_ELI_AUTH_SECKEYLEN * nsec;
406 cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
407 bp->bio_driver2 = malloc(size, M_ELI, M_WAITOK);
408 cbp->bio_data = bp->bio_driver2;
410 /* Clear the error array. */
411 memset((char *)bp->bio_driver2 + cbp->bio_length, 0,
415 * We read more than what is requested, so we have to be ready to read
419 if (cbp->bio_length > maxphys) {
420 cbp2 = g_duplicate_bio(bp);
421 cbp2->bio_length = cbp->bio_length - maxphys;
422 cbp2->bio_data = cbp->bio_data + maxphys;
423 cbp2->bio_offset = cbp->bio_offset + maxphys;
424 cbp2->bio_to = cp->provider;
425 cbp2->bio_done = g_eli_read_done;
426 cbp->bio_length = maxphys;
429 * Read encrypted data from provider.
431 G_ELI_LOGREQ(2, cbp, "Sending request.");
432 g_io_request(cbp, cp);
434 G_ELI_LOGREQ(2, cbp2, "Sending request.");
435 g_io_request(cbp2, cp);
440 * This is the main function responsible for cryptography (ie. communication
441 * with crypto(9) subsystem).
444 * 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
446 * g_eli_start -> G_ELI_AUTH_RUN -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver
449 g_eli_auth_run(struct g_eli_worker *wr, struct bio *bp)
451 struct g_eli_softc *sc;
453 u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
455 u_char *p, *data, *authkey, *plaindata;
458 G_ELI_LOGREQ(3, bp, "%s", __func__);
460 bp->bio_pflags = wr->w_number;
462 /* Sectorsize of decrypted provider eg. 4096. */
463 decr_secsize = bp->bio_to->sectorsize;
464 /* The real sectorsize of encrypted provider, eg. 512. */
465 encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
466 /* Number of data bytes in one encrypted sector, eg. 480. */
467 data_secsize = sc->sc_data_per_sector;
468 /* Number of sectors from decrypted provider, eg. 2. */
469 nsec = bp->bio_length / decr_secsize;
470 /* Number of sectors from encrypted provider, eg. 18. */
471 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
472 /* Last sector number in every big sector, eg. 9. */
473 lsec = sc->sc_bytes_per_sector / encr_secsize;
474 /* Destination offset, used for IV generation. */
475 dstoff = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
477 plaindata = bp->bio_data;
478 if (bp->bio_cmd == BIO_READ) {
479 data = bp->bio_driver2;
480 p = data + encr_secsize * nsec;
481 p += sizeof(int) * nsec;
485 size = encr_secsize * nsec;
486 size += G_ELI_AUTH_SECKEYLEN * nsec;
487 size += sizeof(uintptr_t); /* Space for alignment. */
488 data = malloc(size, M_ELI, M_WAITOK);
489 bp->bio_driver2 = data;
490 p = data + encr_secsize * nsec;
493 bp->bio_children = nsec;
495 #if defined(__mips_n64) || defined(__mips_o64)
496 p = (char *)roundup((uintptr_t)p, sizeof(uintptr_t));
499 for (i = 1; i <= nsec; i++, dstoff += encr_secsize) {
500 crp = crypto_getreq(wr->w_sid, M_WAITOK);
501 authkey = (u_char *)p; p += G_ELI_AUTH_SECKEYLEN;
503 data_secsize = sc->sc_data_per_sector;
504 if ((i % lsec) == 0) {
505 data_secsize = decr_secsize % data_secsize;
507 * Last encrypted sector of each decrypted sector is
508 * only partially filled.
510 if (bp->bio_cmd == BIO_WRITE)
511 memset(data + sc->sc_alen + data_secsize, 0,
512 encr_secsize - sc->sc_alen - data_secsize);
515 if (bp->bio_cmd == BIO_WRITE) {
516 bcopy(plaindata, data + sc->sc_alen, data_secsize);
517 plaindata += data_secsize;
520 crypto_use_buf(crp, data, sc->sc_alen + data_secsize);
521 crp->crp_opaque = (void *)bp;
522 data += encr_secsize;
523 crp->crp_flags = CRYPTO_F_CBIFSYNC;
525 crp->crp_flags |= CRYPTO_F_BATCH;
526 if (bp->bio_cmd == BIO_WRITE) {
527 crp->crp_callback = g_eli_auth_write_done;
528 crp->crp_op = CRYPTO_OP_ENCRYPT |
529 CRYPTO_OP_COMPUTE_DIGEST;
531 crp->crp_callback = g_eli_auth_read_done;
532 crp->crp_op = CRYPTO_OP_DECRYPT |
533 CRYPTO_OP_VERIFY_DIGEST;
536 crp->crp_digest_start = 0;
537 crp->crp_payload_start = sc->sc_alen;
538 crp->crp_payload_length = data_secsize;
539 if ((sc->sc_flags & G_ELI_FLAG_FIRST_KEY) == 0) {
540 crp->crp_cipher_key = g_eli_key_hold(sc, dstoff,
543 if (g_eli_ivlen(sc->sc_ealgo) != 0) {
544 crp->crp_flags |= CRYPTO_F_IV_SEPARATE;
545 g_eli_crypto_ivgen(sc, dstoff, crp->crp_iv,
546 sizeof(crp->crp_iv));
549 g_eli_auth_keygen(sc, dstoff, authkey);
550 crp->crp_auth_key = authkey;
552 error = crypto_dispatch(crp);
553 KASSERT(error == 0, ("crypto_dispatch() failed (error=%d)",