2 * SPDX-License-Identifier: BSD-2-Clause
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 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
33 #include <sys/linker.h>
34 #include <sys/module.h>
36 #include <sys/mutex.h>
38 #include <sys/sysctl.h>
39 #include <sys/kthread.h>
41 #include <sys/sched.h>
43 #include <sys/vnode.h>
47 #include <geom/geom.h>
48 #include <geom/geom_dbg.h>
49 #include <geom/eli/g_eli.h>
50 #include <geom/eli/pkcs5v2.h>
53 * The data layout description when integrity verification is configured.
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
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.
76 * And here is the picture:
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|
85 * da0.eli: +----+----+----+----+----+----+----+----+----+
86 * |480b|480b|480b|480b|480b|480b|480b|480b|256b|
87 * +----+----+----+----+----+----+----+----+----+
89 * +--------------------------------------------+
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.
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
101 * g_eli_start -> g_eli_auth_run -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver
105 * Here we generate key for HMAC. Every sector has its own HMAC key, so it is
106 * not possible to copy sectors.
107 * We cannot depend on fact, that every sector has its own IV, because different
108 * IV doesn't change HMAC, when we use encrypt-then-authenticate method.
111 g_eli_auth_keygen(struct g_eli_softc *sc, off_t offset, u_char *key)
115 /* Copy precalculated SHA256 context. */
116 bcopy(&sc->sc_akeyctx, &ctx, sizeof(ctx));
117 SHA256_Update(&ctx, (uint8_t *)&offset, sizeof(offset));
118 SHA256_Final(key, &ctx);
122 * The function is called after we read and decrypt data.
124 * 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 g_eli_auth_read_done(struct cryptop *crp)
129 struct g_eli_softc *sc;
132 if (crp->crp_etype == EAGAIN) {
133 if (g_eli_crypto_rerun(crp) == 0)
136 bp = (struct bio *)crp->crp_opaque;
138 sc = bp->bio_to->geom->softc;
139 if (crp->crp_etype == 0) {
140 bp->bio_completed += crp->crp_payload_length;
141 G_ELI_DEBUG(3, "Crypto READ request done (%d/%d) (add=%d completed=%jd).",
142 bp->bio_inbed, bp->bio_children, crp->crp_payload_length, (intmax_t)bp->bio_completed);
144 u_int nsec, decr_secsize, encr_secsize, rel_sec;
147 /* Sectorsize of decrypted provider eg. 4096. */
148 decr_secsize = bp->bio_to->sectorsize;
149 /* The real sectorsize of encrypted provider, eg. 512. */
151 LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
152 /* Number of sectors from decrypted provider, eg. 2. */
153 nsec = bp->bio_length / decr_secsize;
154 /* Number of sectors from encrypted provider, eg. 18. */
155 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
156 /* Which relative sector this request decrypted. */
157 rel_sec = ((crp->crp_buf.cb_buf + crp->crp_payload_start) -
158 (char *)bp->bio_driver2) / encr_secsize;
160 errorp = (int *)((char *)bp->bio_driver2 + encr_secsize * nsec +
161 sizeof(int) * rel_sec);
162 *errorp = crp->crp_etype;
164 "Crypto READ request failed (%d/%d) error=%d.",
165 bp->bio_inbed, bp->bio_children, crp->crp_etype);
166 if (bp->bio_error == 0 || bp->bio_error == EINTEGRITY)
167 bp->bio_error = crp->crp_etype == EBADMSG ?
168 EINTEGRITY : crp->crp_etype;
170 if (crp->crp_cipher_key != NULL)
171 g_eli_key_drop(sc, __DECONST(void *, crp->crp_cipher_key));
174 * Do we have all sectors already?
176 if (bp->bio_inbed < bp->bio_children)
179 if (bp->bio_error == 0) {
180 u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
181 u_char *srcdata, *dstdata;
183 /* Sectorsize of decrypted provider eg. 4096. */
184 decr_secsize = bp->bio_to->sectorsize;
185 /* The real sectorsize of encrypted provider, eg. 512. */
186 encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
187 /* Number of data bytes in one encrypted sector, eg. 480. */
188 data_secsize = sc->sc_data_per_sector;
189 /* Number of sectors from decrypted provider, eg. 2. */
190 nsec = bp->bio_length / decr_secsize;
191 /* Number of sectors from encrypted provider, eg. 18. */
192 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
193 /* Last sector number in every big sector, eg. 9. */
194 lsec = sc->sc_bytes_per_sector / encr_secsize;
196 srcdata = bp->bio_driver2;
197 dstdata = bp->bio_data;
199 for (i = 1; i <= nsec; i++) {
200 data_secsize = sc->sc_data_per_sector;
202 data_secsize = decr_secsize % data_secsize;
203 bcopy(srcdata + sc->sc_alen, dstdata, data_secsize);
204 srcdata += encr_secsize;
205 dstdata += data_secsize;
207 } else if (bp->bio_error == EINTEGRITY) {
208 u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
210 off_t coroff, corsize, dstoff;
212 /* Sectorsize of decrypted provider eg. 4096. */
213 decr_secsize = bp->bio_to->sectorsize;
214 /* The real sectorsize of encrypted provider, eg. 512. */
215 encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
216 /* Number of data bytes in one encrypted sector, eg. 480. */
217 data_secsize = sc->sc_data_per_sector;
218 /* Number of sectors from decrypted provider, eg. 2. */
219 nsec = bp->bio_length / decr_secsize;
220 /* Number of sectors from encrypted provider, eg. 18. */
221 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
222 /* Last sector number in every big sector, eg. 9. */
223 lsec = sc->sc_bytes_per_sector / encr_secsize;
225 errorp = (int *)((char *)bp->bio_driver2 + encr_secsize * nsec);
228 dstoff = bp->bio_offset;
230 for (i = 1; i <= nsec; i++) {
231 data_secsize = sc->sc_data_per_sector;
233 data_secsize = decr_secsize % data_secsize;
234 if (errorp[i - 1] == EBADMSG) {
236 * Corruption detected, remember the offset if
237 * this is the first corrupted sector and
242 corsize += data_secsize;
245 * No corruption, good.
246 * Report previous corruption if there was one.
249 G_ELI_DEBUG(0, "%s: Failed to authenticate %jd "
250 "bytes of data at offset %jd.",
251 sc->sc_name, (intmax_t)corsize,
257 dstoff += data_secsize;
259 /* Report previous corruption if there was one. */
261 G_ELI_DEBUG(0, "%s: Failed to authenticate %jd "
262 "bytes of data at offset %jd.",
263 sc->sc_name, (intmax_t)corsize, (intmax_t)coroff);
267 if (bp->bio_error != 0) {
268 if (bp->bio_error != EINTEGRITY) {
270 "Crypto READ request failed (error=%d).",
273 bp->bio_completed = 0;
276 * Read is finished, send it up.
278 g_io_deliver(bp, bp->bio_error);
279 atomic_subtract_int(&sc->sc_inflight, 1);
284 * The function is called after data encryption.
286 * g_eli_start -> g_eli_auth_run -> G_ELI_AUTH_WRITE_DONE -> g_io_request -> g_eli_write_done -> g_io_deliver
289 g_eli_auth_write_done(struct cryptop *crp)
291 struct g_eli_softc *sc;
292 struct g_consumer *cp;
293 struct bio *bp, *cbp, *cbp2;
296 if (crp->crp_etype == EAGAIN) {
297 if (g_eli_crypto_rerun(crp) == 0)
300 bp = (struct bio *)crp->crp_opaque;
302 if (crp->crp_etype == 0) {
303 G_ELI_DEBUG(3, "Crypto WRITE request done (%d/%d).",
304 bp->bio_inbed, bp->bio_children);
306 G_ELI_DEBUG(1, "Crypto WRITE request failed (%d/%d) error=%d.",
307 bp->bio_inbed, bp->bio_children, crp->crp_etype);
308 if (bp->bio_error == 0)
309 bp->bio_error = crp->crp_etype;
311 sc = bp->bio_to->geom->softc;
312 if (crp->crp_cipher_key != NULL)
313 g_eli_key_drop(sc, __DECONST(void *, crp->crp_cipher_key));
316 * All sectors are already encrypted?
318 if (bp->bio_inbed < bp->bio_children)
320 if (bp->bio_error != 0) {
321 G_ELI_LOGREQ(0, bp, "Crypto WRITE request failed (error=%d).",
324 cbp = bp->bio_driver1;
325 bp->bio_driver1 = NULL;
327 g_io_deliver(bp, bp->bio_error);
328 atomic_subtract_int(&sc->sc_inflight, 1);
331 cp = LIST_FIRST(&sc->sc_geom->consumer);
332 cbp = bp->bio_driver1;
333 bp->bio_driver1 = NULL;
334 cbp->bio_to = cp->provider;
335 cbp->bio_done = g_eli_write_done;
337 /* Number of sectors from decrypted provider, eg. 1. */
338 nsec = bp->bio_length / bp->bio_to->sectorsize;
339 /* Number of sectors from encrypted provider, eg. 9. */
340 nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize;
342 cbp->bio_length = cp->provider->sectorsize * nsec;
343 cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
344 cbp->bio_data = bp->bio_driver2;
347 * We write more than what is requested, so we have to be ready to write
351 if (cbp->bio_length > maxphys) {
352 cbp2 = g_duplicate_bio(bp);
353 cbp2->bio_length = cbp->bio_length - maxphys;
354 cbp2->bio_data = cbp->bio_data + maxphys;
355 cbp2->bio_offset = cbp->bio_offset + maxphys;
356 cbp2->bio_to = cp->provider;
357 cbp2->bio_done = g_eli_write_done;
358 cbp->bio_length = maxphys;
361 * Send encrypted data to the provider.
363 G_ELI_LOGREQ(2, cbp, "Sending request.");
365 bp->bio_children = (cbp2 != NULL ? 2 : 1);
366 g_io_request(cbp, cp);
368 G_ELI_LOGREQ(2, cbp2, "Sending request.");
369 g_io_request(cbp2, cp);
375 g_eli_auth_read(struct g_eli_softc *sc, struct bio *bp)
377 struct g_consumer *cp;
378 struct bio *cbp, *cbp2;
382 G_ELI_SETWORKER(bp->bio_pflags, 0);
384 cp = LIST_FIRST(&sc->sc_geom->consumer);
385 cbp = bp->bio_driver1;
386 bp->bio_driver1 = NULL;
387 cbp->bio_to = cp->provider;
388 cbp->bio_done = g_eli_read_done;
390 /* Number of sectors from decrypted provider, eg. 1. */
391 nsec = bp->bio_length / bp->bio_to->sectorsize;
392 /* Number of sectors from encrypted provider, eg. 9. */
393 nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize;
395 cbp->bio_length = cp->provider->sectorsize * nsec;
396 size = cbp->bio_length;
397 size += sizeof(int) * nsec;
398 size += G_ELI_AUTH_SECKEYLEN * nsec;
399 cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
400 if (!g_eli_alloc_data(bp, size)) {
401 G_ELI_LOGREQ(0, bp, "Crypto auth read request failed (ENOMEM)");
403 bp->bio_error = ENOMEM;
404 g_io_deliver(bp, bp->bio_error);
405 atomic_subtract_int(&sc->sc_inflight, 1);
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;
452 struct cryptopq crpq;
454 u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
456 u_char *p, *data, *authkey, *plaindata;
457 int error __diagused;
460 G_ELI_LOGREQ(3, bp, "%s", __func__);
462 G_ELI_SETWORKER(bp->bio_pflags, wr->w_number);
464 /* Sectorsize of decrypted provider eg. 4096. */
465 decr_secsize = bp->bio_to->sectorsize;
466 /* The real sectorsize of encrypted provider, eg. 512. */
467 encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
468 /* Number of data bytes in one encrypted sector, eg. 480. */
469 data_secsize = sc->sc_data_per_sector;
470 /* Number of sectors from decrypted provider, eg. 2. */
471 nsec = bp->bio_length / decr_secsize;
472 /* Number of sectors from encrypted provider, eg. 18. */
473 nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
474 /* Last sector number in every big sector, eg. 9. */
475 lsec = sc->sc_bytes_per_sector / encr_secsize;
476 /* Destination offset, used for IV generation. */
477 dstoff = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
479 plaindata = bp->bio_data;
480 if (bp->bio_cmd == BIO_READ) {
481 data = bp->bio_driver2;
482 p = data + encr_secsize * nsec;
483 p += sizeof(int) * nsec;
487 size = encr_secsize * nsec;
488 size += G_ELI_AUTH_SECKEYLEN * nsec;
489 size += sizeof(uintptr_t); /* Space for alignment. */
490 if (!g_eli_alloc_data(bp, size)) {
491 G_ELI_LOGREQ(0, bp, "Crypto request failed (ENOMEM)");
492 if (bp->bio_driver1 != NULL) {
493 g_destroy_bio(bp->bio_driver1);
494 bp->bio_driver1 = NULL;
496 bp->bio_error = ENOMEM;
497 g_io_deliver(bp, bp->bio_error);
499 atomic_subtract_int(&sc->sc_inflight, 1);
502 data = bp->bio_driver2;
503 p = data + encr_secsize * nsec;
506 bp->bio_children = nsec;
508 #if defined(__mips_n64) || defined(__mips_o64)
509 p = (char *)roundup((uintptr_t)p, sizeof(uintptr_t));
513 batch = atomic_load_int(&g_eli_batch) != 0;
515 for (i = 1; i <= nsec; i++, dstoff += encr_secsize) {
516 crp = crypto_getreq(wr->w_sid, M_WAITOK);
517 authkey = (u_char *)p; p += G_ELI_AUTH_SECKEYLEN;
519 data_secsize = sc->sc_data_per_sector;
520 if ((i % lsec) == 0) {
521 data_secsize = decr_secsize % data_secsize;
523 * Last encrypted sector of each decrypted sector is
524 * only partially filled.
526 if (bp->bio_cmd == BIO_WRITE)
527 memset(data + sc->sc_alen + data_secsize, 0,
528 encr_secsize - sc->sc_alen - data_secsize);
529 } else if (data_secsize + sc->sc_alen != encr_secsize) {
531 * If the HMAC size is not a multiple of 128 bits, the
532 * per-sector data size is rounded down to ensure that
533 * encryption can be performed without requiring any
534 * padding. In this case, each sector contains unused
537 if (bp->bio_cmd == BIO_WRITE)
538 memset(data + sc->sc_alen + data_secsize, 0,
539 encr_secsize - sc->sc_alen - data_secsize);
542 if (bp->bio_cmd == BIO_WRITE) {
543 bcopy(plaindata, data + sc->sc_alen, data_secsize);
544 plaindata += data_secsize;
547 crypto_use_buf(crp, data, sc->sc_alen + data_secsize);
548 crp->crp_opaque = (void *)bp;
549 data += encr_secsize;
550 crp->crp_flags = CRYPTO_F_CBIFSYNC;
551 if (bp->bio_cmd == BIO_WRITE) {
552 crp->crp_callback = g_eli_auth_write_done;
553 crp->crp_op = CRYPTO_OP_ENCRYPT |
554 CRYPTO_OP_COMPUTE_DIGEST;
556 crp->crp_callback = g_eli_auth_read_done;
557 crp->crp_op = CRYPTO_OP_DECRYPT |
558 CRYPTO_OP_VERIFY_DIGEST;
561 crp->crp_digest_start = 0;
562 crp->crp_payload_start = sc->sc_alen;
563 crp->crp_payload_length = data_secsize;
564 if ((sc->sc_flags & G_ELI_FLAG_FIRST_KEY) == 0) {
565 crp->crp_cipher_key = g_eli_key_hold(sc, dstoff,
568 if (g_eli_ivlen(sc->sc_ealgo) != 0) {
569 crp->crp_flags |= CRYPTO_F_IV_SEPARATE;
570 g_eli_crypto_ivgen(sc, dstoff, crp->crp_iv,
571 sizeof(crp->crp_iv));
574 g_eli_auth_keygen(sc, dstoff, authkey);
575 crp->crp_auth_key = authkey;
578 TAILQ_INSERT_TAIL(&crpq, crp, crp_next);
580 error = crypto_dispatch(crp);
582 ("crypto_dispatch() failed (error=%d)", error));
587 crypto_dispatch_batch(&crpq, 0);