xref: /freebsd/sys/geom/eli/g_eli_integrity.c (revision 1a498d2e689f9e8220e2ad64b018eb1f0d11127e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2005-2011 Pawel Jakub Dawidek <pawel@dawidek.net>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
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.
15  *
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
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
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>
37 #include <sys/lock.h>
38 #include <sys/mutex.h>
39 #include <sys/bio.h>
40 #include <sys/sysctl.h>
41 #include <sys/malloc.h>
42 #include <sys/kthread.h>
43 #include <sys/proc.h>
44 #include <sys/sched.h>
45 #include <sys/smp.h>
46 #include <sys/vnode.h>
47 
48 #include <vm/uma.h>
49 
50 #include <geom/geom.h>
51 #include <geom/eli/g_eli.h>
52 #include <geom/eli/pkcs5v2.h>
53 
54 /*
55  * The data layout description when integrity verification is configured.
56  *
57  * One of the most important assumption here is that authenticated data and its
58  * HMAC has to be stored in the same place (namely in the same sector) to make
59  * it work reliable.
60  * The problem is that file systems work only with sectors that are multiple of
61  * 512 bytes and a power of two number.
62  * My idea to implement it is as follows.
63  * Let's store HMAC in sector. This is a must. This leaves us 480 bytes for
64  * data. We can't use that directly (ie. we can't create provider with 480 bytes
65  * sector size). We need another sector from where we take only 32 bytes of data
66  * and we store HMAC of this data as well. This takes two sectors from the
67  * original provider at the input and leaves us one sector of authenticated data
68  * at the output. Not very efficient, but you got the idea.
69  * Now, let's assume, we want to create provider with 4096 bytes sector.
70  * To output 4096 bytes of authenticated data we need 8x480 plus 1x256, so we
71  * need nine 512-bytes sectors at the input to get one 4096-bytes sector at the
72  * output. That's better. With 4096 bytes sector we can use 89% of size of the
73  * original provider. I find it as an acceptable cost.
74  * The reliability comes from the fact, that every HMAC stored inside the sector
75  * is calculated only for the data in the same sector, so its impossible to
76  * write new data and leave old HMAC or vice versa.
77  *
78  * And here is the picture:
79  *
80  * da0: +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+-----+
81  *      |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |480b| |32b |256b |
82  *      |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data| |HMAC|Data |
83  *      +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+----+ +----+-----+
84  *      |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |512 bytes| |288 bytes |
85  *      +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ +---------+ |224 unused|
86  *                                                                                                      +----------+
87  * da0.eli: +----+----+----+----+----+----+----+----+----+
88  *          |480b|480b|480b|480b|480b|480b|480b|480b|256b|
89  *          +----+----+----+----+----+----+----+----+----+
90  *          |                 4096 bytes                 |
91  *          +--------------------------------------------+
92  *
93  * PS. You can use any sector size with geli(8). My example is using 4kB,
94  *     because it's most efficient. For 8kB sectors you need 2 extra sectors,
95  *     so the cost is the same as for 4kB sectors.
96  */
97 
98 /*
99  * Code paths:
100  * BIO_READ:
101  *	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
102  * BIO_WRITE:
103  *	g_eli_start -> g_eli_auth_run -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver
104  */
105 
106 MALLOC_DECLARE(M_ELI);
107 
108 /*
109  * Here we generate key for HMAC. Every sector has its own HMAC key, so it is
110  * not possible to copy sectors.
111  * We cannot depend on fact, that every sector has its own IV, because different
112  * IV doesn't change HMAC, when we use encrypt-then-authenticate method.
113  */
114 static void
115 g_eli_auth_keygen(struct g_eli_softc *sc, off_t offset, u_char *key)
116 {
117 	SHA256_CTX ctx;
118 
119 	/* Copy precalculated SHA256 context. */
120 	bcopy(&sc->sc_akeyctx, &ctx, sizeof(ctx));
121 	SHA256_Update(&ctx, (uint8_t *)&offset, sizeof(offset));
122 	SHA256_Final(key, &ctx);
123 }
124 
125 /*
126  * The function is called after we read and decrypt data.
127  *
128  * 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
129  */
130 static int
131 g_eli_auth_read_done(struct cryptop *crp)
132 {
133 	struct g_eli_softc *sc;
134 	struct bio *bp;
135 
136 	if (crp->crp_etype == EAGAIN) {
137 		if (g_eli_crypto_rerun(crp) == 0)
138 			return (0);
139 	}
140 	bp = (struct bio *)crp->crp_opaque;
141 	bp->bio_inbed++;
142 	if (crp->crp_etype == 0) {
143 		bp->bio_completed += crp->crp_olen;
144 		G_ELI_DEBUG(3, "Crypto READ request done (%d/%d) (add=%jd completed=%jd).",
145 		    bp->bio_inbed, bp->bio_children, (intmax_t)crp->crp_olen, (intmax_t)bp->bio_completed);
146 	} else {
147 		G_ELI_DEBUG(1, "Crypto READ request failed (%d/%d) error=%d.",
148 		    bp->bio_inbed, bp->bio_children, crp->crp_etype);
149 		if (bp->bio_error == 0)
150 			bp->bio_error = crp->crp_etype;
151 	}
152 	sc = bp->bio_to->geom->softc;
153 	g_eli_key_drop(sc, crp->crp_desc->crd_next->crd_key);
154 	/*
155 	 * Do we have all sectors already?
156 	 */
157 	if (bp->bio_inbed < bp->bio_children)
158 		return (0);
159 	if (bp->bio_error == 0) {
160 		u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
161 		u_char *srcdata, *dstdata, *auth;
162 		off_t coroff, corsize;
163 
164 		/*
165 		 * Verify data integrity based on calculated and read HMACs.
166 		 */
167 		/* Sectorsize of decrypted provider eg. 4096. */
168 		decr_secsize = bp->bio_to->sectorsize;
169 		/* The real sectorsize of encrypted provider, eg. 512. */
170 		encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
171 		/* Number of data bytes in one encrypted sector, eg. 480. */
172 		data_secsize = sc->sc_data_per_sector;
173 		/* Number of sectors from decrypted provider, eg. 2. */
174 		nsec = bp->bio_length / decr_secsize;
175 		/* Number of sectors from encrypted provider, eg. 18. */
176 		nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
177 		/* Last sector number in every big sector, eg. 9. */
178 		lsec = sc->sc_bytes_per_sector / encr_secsize;
179 
180 		srcdata = bp->bio_driver2;
181 		dstdata = bp->bio_data;
182 		auth = srcdata + encr_secsize * nsec;
183 		coroff = -1;
184 		corsize = 0;
185 
186 		for (i = 1; i <= nsec; i++) {
187 			data_secsize = sc->sc_data_per_sector;
188 			if ((i % lsec) == 0)
189 				data_secsize = decr_secsize % data_secsize;
190 			if (bcmp(srcdata, auth, sc->sc_alen) != 0) {
191 				/*
192 				 * Curruption detected, remember the offset if
193 				 * this is the first corrupted sector and
194 				 * increase size.
195 				 */
196 				if (bp->bio_error == 0)
197 					bp->bio_error = -1;
198 				if (coroff == -1) {
199 					coroff = bp->bio_offset +
200 					    (dstdata - (u_char *)bp->bio_data);
201 				}
202 				corsize += data_secsize;
203 			} else {
204 				/*
205 				 * No curruption, good.
206 				 * Report previous corruption if there was one.
207 				 */
208 				if (coroff != -1) {
209 					G_ELI_DEBUG(0, "%s: Failed to authenticate %jd "
210 					    "bytes of data at offset %jd.",
211 					    sc->sc_name, (intmax_t)corsize,
212 					    (intmax_t)coroff);
213 					coroff = -1;
214 					corsize = 0;
215 				}
216 				bcopy(srcdata + sc->sc_alen, dstdata,
217 				    data_secsize);
218 			}
219 			srcdata += encr_secsize;
220 			dstdata += data_secsize;
221 			auth += sc->sc_alen;
222 		}
223 		/* Report previous corruption if there was one. */
224 		if (coroff != -1) {
225 			G_ELI_DEBUG(0, "%s: Failed to authenticate %jd "
226 			    "bytes of data at offset %jd.",
227 			    sc->sc_name, (intmax_t)corsize, (intmax_t)coroff);
228 		}
229 	}
230 	free(bp->bio_driver2, M_ELI);
231 	bp->bio_driver2 = NULL;
232 	if (bp->bio_error != 0) {
233 		if (bp->bio_error == -1)
234 			bp->bio_error = EINVAL;
235 		else {
236 			G_ELI_LOGREQ(0, bp,
237 			    "Crypto READ request failed (error=%d).",
238 			    bp->bio_error);
239 		}
240 		bp->bio_completed = 0;
241 	}
242 	/*
243 	 * Read is finished, send it up.
244 	 */
245 	g_io_deliver(bp, bp->bio_error);
246 	atomic_subtract_int(&sc->sc_inflight, 1);
247 	return (0);
248 }
249 
250 /*
251  * The function is called after data encryption.
252  *
253  * g_eli_start -> g_eli_auth_run -> G_ELI_AUTH_WRITE_DONE -> g_io_request -> g_eli_write_done -> g_io_deliver
254  */
255 static int
256 g_eli_auth_write_done(struct cryptop *crp)
257 {
258 	struct g_eli_softc *sc;
259 	struct g_consumer *cp;
260 	struct bio *bp, *cbp, *cbp2;
261 	u_int nsec;
262 
263 	if (crp->crp_etype == EAGAIN) {
264 		if (g_eli_crypto_rerun(crp) == 0)
265 			return (0);
266 	}
267 	bp = (struct bio *)crp->crp_opaque;
268 	bp->bio_inbed++;
269 	if (crp->crp_etype == 0) {
270 		G_ELI_DEBUG(3, "Crypto WRITE request done (%d/%d).",
271 		    bp->bio_inbed, bp->bio_children);
272 	} else {
273 		G_ELI_DEBUG(1, "Crypto WRITE request failed (%d/%d) error=%d.",
274 		    bp->bio_inbed, bp->bio_children, crp->crp_etype);
275 		if (bp->bio_error == 0)
276 			bp->bio_error = crp->crp_etype;
277 	}
278 	sc = bp->bio_to->geom->softc;
279 	g_eli_key_drop(sc, crp->crp_desc->crd_key);
280 	/*
281 	 * All sectors are already encrypted?
282 	 */
283 	if (bp->bio_inbed < bp->bio_children)
284 		return (0);
285 	if (bp->bio_error != 0) {
286 		G_ELI_LOGREQ(0, bp, "Crypto WRITE request failed (error=%d).",
287 		    bp->bio_error);
288 		free(bp->bio_driver2, M_ELI);
289 		bp->bio_driver2 = NULL;
290 		cbp = bp->bio_driver1;
291 		bp->bio_driver1 = NULL;
292 		g_destroy_bio(cbp);
293 		g_io_deliver(bp, bp->bio_error);
294 		atomic_subtract_int(&sc->sc_inflight, 1);
295 		return (0);
296 	}
297 	cp = LIST_FIRST(&sc->sc_geom->consumer);
298 	cbp = bp->bio_driver1;
299 	bp->bio_driver1 = NULL;
300 	cbp->bio_to = cp->provider;
301 	cbp->bio_done = g_eli_write_done;
302 
303 	/* Number of sectors from decrypted provider, eg. 1. */
304 	nsec = bp->bio_length / bp->bio_to->sectorsize;
305 	/* Number of sectors from encrypted provider, eg. 9. */
306 	nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize;
307 
308 	cbp->bio_length = cp->provider->sectorsize * nsec;
309 	cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
310 	cbp->bio_data = bp->bio_driver2;
311 
312 	/*
313 	 * We write more than what is requested, so we have to be ready to write
314 	 * more than MAXPHYS.
315 	 */
316 	cbp2 = NULL;
317 	if (cbp->bio_length > MAXPHYS) {
318 		cbp2 = g_duplicate_bio(bp);
319 		cbp2->bio_length = cbp->bio_length - MAXPHYS;
320 		cbp2->bio_data = cbp->bio_data + MAXPHYS;
321 		cbp2->bio_offset = cbp->bio_offset + MAXPHYS;
322 		cbp2->bio_to = cp->provider;
323 		cbp2->bio_done = g_eli_write_done;
324 		cbp->bio_length = MAXPHYS;
325 	}
326 	/*
327 	 * Send encrypted data to the provider.
328 	 */
329 	G_ELI_LOGREQ(2, cbp, "Sending request.");
330 	bp->bio_inbed = 0;
331 	bp->bio_children = (cbp2 != NULL ? 2 : 1);
332 	g_io_request(cbp, cp);
333 	if (cbp2 != NULL) {
334 		G_ELI_LOGREQ(2, cbp2, "Sending request.");
335 		g_io_request(cbp2, cp);
336 	}
337 	return (0);
338 }
339 
340 void
341 g_eli_auth_read(struct g_eli_softc *sc, struct bio *bp)
342 {
343 	struct g_consumer *cp;
344 	struct bio *cbp, *cbp2;
345 	size_t size;
346 	off_t nsec;
347 
348 	bp->bio_pflags = 0;
349 
350 	cp = LIST_FIRST(&sc->sc_geom->consumer);
351 	cbp = bp->bio_driver1;
352 	bp->bio_driver1 = NULL;
353 	cbp->bio_to = cp->provider;
354 	cbp->bio_done = g_eli_read_done;
355 
356 	/* Number of sectors from decrypted provider, eg. 1. */
357 	nsec = bp->bio_length / bp->bio_to->sectorsize;
358 	/* Number of sectors from encrypted provider, eg. 9. */
359 	nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize;
360 
361 	cbp->bio_length = cp->provider->sectorsize * nsec;
362 	size = cbp->bio_length;
363 	size += sc->sc_alen * nsec;
364 	size += sizeof(struct cryptop) * nsec;
365 	size += sizeof(struct cryptodesc) * nsec * 2;
366 	size += G_ELI_AUTH_SECKEYLEN * nsec;
367 	cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
368 	bp->bio_driver2 = malloc(size, M_ELI, M_WAITOK);
369 	cbp->bio_data = bp->bio_driver2;
370 
371 	/*
372 	 * We read more than what is requested, so we have to be ready to read
373 	 * more than MAXPHYS.
374 	 */
375 	cbp2 = NULL;
376 	if (cbp->bio_length > MAXPHYS) {
377 		cbp2 = g_duplicate_bio(bp);
378 		cbp2->bio_length = cbp->bio_length - MAXPHYS;
379 		cbp2->bio_data = cbp->bio_data + MAXPHYS;
380 		cbp2->bio_offset = cbp->bio_offset + MAXPHYS;
381 		cbp2->bio_to = cp->provider;
382 		cbp2->bio_done = g_eli_read_done;
383 		cbp->bio_length = MAXPHYS;
384 	}
385 	/*
386 	 * Read encrypted data from provider.
387 	 */
388 	G_ELI_LOGREQ(2, cbp, "Sending request.");
389 	g_io_request(cbp, cp);
390 	if (cbp2 != NULL) {
391 		G_ELI_LOGREQ(2, cbp2, "Sending request.");
392 		g_io_request(cbp2, cp);
393 	}
394 }
395 
396 /*
397  * This is the main function responsible for cryptography (ie. communication
398  * with crypto(9) subsystem).
399  *
400  * BIO_READ:
401  *	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
402  * BIO_WRITE:
403  *	g_eli_start -> G_ELI_AUTH_RUN -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver
404  */
405 void
406 g_eli_auth_run(struct g_eli_worker *wr, struct bio *bp)
407 {
408 	struct g_eli_softc *sc;
409 	struct cryptop *crp;
410 	struct cryptodesc *crde, *crda;
411 	u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
412 	off_t dstoff;
413 	u_char *p, *data, *auth, *authkey, *plaindata;
414 	int error;
415 
416 	G_ELI_LOGREQ(3, bp, "%s", __func__);
417 
418 	bp->bio_pflags = wr->w_number;
419 	sc = wr->w_softc;
420 	/* Sectorsize of decrypted provider eg. 4096. */
421 	decr_secsize = bp->bio_to->sectorsize;
422 	/* The real sectorsize of encrypted provider, eg. 512. */
423 	encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
424 	/* Number of data bytes in one encrypted sector, eg. 480. */
425 	data_secsize = sc->sc_data_per_sector;
426 	/* Number of sectors from decrypted provider, eg. 2. */
427 	nsec = bp->bio_length / decr_secsize;
428 	/* Number of sectors from encrypted provider, eg. 18. */
429 	nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
430 	/* Last sector number in every big sector, eg. 9. */
431 	lsec = sc->sc_bytes_per_sector / encr_secsize;
432 	/* Destination offset, used for IV generation. */
433 	dstoff = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
434 
435 	auth = NULL;	/* Silence compiler warning. */
436 	plaindata = bp->bio_data;
437 	if (bp->bio_cmd == BIO_READ) {
438 		data = bp->bio_driver2;
439 		auth = data + encr_secsize * nsec;
440 		p = auth + sc->sc_alen * nsec;
441 	} else {
442 		size_t size;
443 
444 		size = encr_secsize * nsec;
445 		size += sizeof(*crp) * nsec;
446 		size += sizeof(*crde) * nsec;
447 		size += sizeof(*crda) * nsec;
448 		size += G_ELI_AUTH_SECKEYLEN * nsec;
449 		size += sizeof(uintptr_t);	/* Space for alignment. */
450 		data = malloc(size, M_ELI, M_WAITOK);
451 		bp->bio_driver2 = data;
452 		p = data + encr_secsize * nsec;
453 	}
454 	bp->bio_inbed = 0;
455 	bp->bio_children = nsec;
456 
457 #if defined(__mips_n64) || defined(__mips_o64)
458 	p = (char *)roundup((uintptr_t)p, sizeof(uintptr_t));
459 #endif
460 
461 	for (i = 1; i <= nsec; i++, dstoff += encr_secsize) {
462 		crp = (struct cryptop *)p;	p += sizeof(*crp);
463 		crde = (struct cryptodesc *)p;	p += sizeof(*crde);
464 		crda = (struct cryptodesc *)p;	p += sizeof(*crda);
465 		authkey = (u_char *)p;		p += G_ELI_AUTH_SECKEYLEN;
466 
467 		data_secsize = sc->sc_data_per_sector;
468 		if ((i % lsec) == 0) {
469 			data_secsize = decr_secsize % data_secsize;
470 			/*
471 			 * Last encrypted sector of each decrypted sector is
472 			 * only partially filled.
473 			 */
474 			if (bp->bio_cmd == BIO_WRITE)
475 				memset(data + sc->sc_alen + data_secsize, 0,
476 				    encr_secsize - sc->sc_alen - data_secsize);
477 		}
478 
479 		if (bp->bio_cmd == BIO_READ) {
480 			/* Remember read HMAC. */
481 			bcopy(data, auth, sc->sc_alen);
482 			auth += sc->sc_alen;
483 			/* TODO: bzero(9) can be commented out later. */
484 			bzero(data, sc->sc_alen);
485 		} else {
486 			bcopy(plaindata, data + sc->sc_alen, data_secsize);
487 			plaindata += data_secsize;
488 		}
489 
490 		crp->crp_session = wr->w_sid;
491 		crp->crp_ilen = sc->sc_alen + data_secsize;
492 		crp->crp_olen = data_secsize;
493 		crp->crp_opaque = (void *)bp;
494 		crp->crp_buf = (void *)data;
495 		data += encr_secsize;
496 		crp->crp_flags = CRYPTO_F_CBIFSYNC;
497 		if (g_eli_batch)
498 			crp->crp_flags |= CRYPTO_F_BATCH;
499 		if (bp->bio_cmd == BIO_WRITE) {
500 			crp->crp_callback = g_eli_auth_write_done;
501 			crp->crp_desc = crde;
502 			crde->crd_next = crda;
503 			crda->crd_next = NULL;
504 		} else {
505 			crp->crp_callback = g_eli_auth_read_done;
506 			crp->crp_desc = crda;
507 			crda->crd_next = crde;
508 			crde->crd_next = NULL;
509 		}
510 
511 		crde->crd_skip = sc->sc_alen;
512 		crde->crd_len = data_secsize;
513 		crde->crd_flags = CRD_F_IV_EXPLICIT | CRD_F_IV_PRESENT;
514 		if ((sc->sc_flags & G_ELI_FLAG_FIRST_KEY) == 0)
515 			crde->crd_flags |= CRD_F_KEY_EXPLICIT;
516 		if (bp->bio_cmd == BIO_WRITE)
517 			crde->crd_flags |= CRD_F_ENCRYPT;
518 		crde->crd_alg = sc->sc_ealgo;
519 		crde->crd_key = g_eli_key_hold(sc, dstoff, encr_secsize);
520 		crde->crd_klen = sc->sc_ekeylen;
521 		if (sc->sc_ealgo == CRYPTO_AES_XTS)
522 			crde->crd_klen <<= 1;
523 		g_eli_crypto_ivgen(sc, dstoff, crde->crd_iv,
524 		    sizeof(crde->crd_iv));
525 
526 		crda->crd_skip = sc->sc_alen;
527 		crda->crd_len = data_secsize;
528 		crda->crd_inject = 0;
529 		crda->crd_flags = CRD_F_KEY_EXPLICIT;
530 		crda->crd_alg = sc->sc_aalgo;
531 		g_eli_auth_keygen(sc, dstoff, authkey);
532 		crda->crd_key = authkey;
533 		crda->crd_klen = G_ELI_AUTH_SECKEYLEN * 8;
534 
535 		crp->crp_etype = 0;
536 		error = crypto_dispatch(crp);
537 		KASSERT(error == 0, ("crypto_dispatch() failed (error=%d)",
538 		    error));
539 	}
540 }
541