xref: /freebsd/sys/geom/eli/g_eli_integrity.c (revision d4eeb02986980bf33dd56c41ceb9fc5f180c0d47)
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/kthread.h>
42 #include <sys/proc.h>
43 #include <sys/sched.h>
44 #include <sys/smp.h>
45 #include <sys/vnode.h>
46 
47 #include <vm/uma.h>
48 
49 #include <geom/geom.h>
50 #include <geom/geom_dbg.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 /*
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 	sc = bp->bio_to->geom->softc;
141 	if (crp->crp_etype == 0) {
142 		bp->bio_completed += crp->crp_payload_length;
143 		G_ELI_DEBUG(3, "Crypto READ request done (%d/%d) (add=%d completed=%jd).",
144 		    bp->bio_inbed, bp->bio_children, crp->crp_payload_length, (intmax_t)bp->bio_completed);
145 	} else {
146 		u_int nsec, decr_secsize, encr_secsize, rel_sec;
147 		int *errorp;
148 
149 		/* Sectorsize of decrypted provider eg. 4096. */
150 		decr_secsize = bp->bio_to->sectorsize;
151 		/* The real sectorsize of encrypted provider, eg. 512. */
152 		encr_secsize =
153 		    LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
154 		/* Number of sectors from decrypted provider, eg. 2. */
155 		nsec = bp->bio_length / decr_secsize;
156 		/* Number of sectors from encrypted provider, eg. 18. */
157 		nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
158 		/* Which relative sector this request decrypted. */
159 		rel_sec = ((crp->crp_buf.cb_buf + crp->crp_payload_start) -
160 		    (char *)bp->bio_driver2) / encr_secsize;
161 
162 		errorp = (int *)((char *)bp->bio_driver2 + encr_secsize * nsec +
163 		    sizeof(int) * rel_sec);
164 		*errorp = crp->crp_etype;
165 		G_ELI_DEBUG(1,
166 		    "Crypto READ request failed (%d/%d) error=%d.",
167 		    bp->bio_inbed, bp->bio_children, crp->crp_etype);
168 		if (bp->bio_error == 0 || bp->bio_error == EINTEGRITY)
169 			bp->bio_error = crp->crp_etype == EBADMSG ?
170 			    EINTEGRITY : crp->crp_etype;
171 	}
172 	if (crp->crp_cipher_key != NULL)
173 		g_eli_key_drop(sc, __DECONST(void *, crp->crp_cipher_key));
174 	crypto_freereq(crp);
175 	/*
176 	 * Do we have all sectors already?
177 	 */
178 	if (bp->bio_inbed < bp->bio_children)
179 		return (0);
180 
181 	if (bp->bio_error == 0) {
182 		u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
183 		u_char *srcdata, *dstdata;
184 
185 		/* Sectorsize of decrypted provider eg. 4096. */
186 		decr_secsize = bp->bio_to->sectorsize;
187 		/* The real sectorsize of encrypted provider, eg. 512. */
188 		encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
189 		/* Number of data bytes in one encrypted sector, eg. 480. */
190 		data_secsize = sc->sc_data_per_sector;
191 		/* Number of sectors from decrypted provider, eg. 2. */
192 		nsec = bp->bio_length / decr_secsize;
193 		/* Number of sectors from encrypted provider, eg. 18. */
194 		nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
195 		/* Last sector number in every big sector, eg. 9. */
196 		lsec = sc->sc_bytes_per_sector / encr_secsize;
197 
198 		srcdata = bp->bio_driver2;
199 		dstdata = bp->bio_data;
200 
201 		for (i = 1; i <= nsec; i++) {
202 			data_secsize = sc->sc_data_per_sector;
203 			if ((i % lsec) == 0)
204 				data_secsize = decr_secsize % data_secsize;
205 			bcopy(srcdata + sc->sc_alen, dstdata, data_secsize);
206 			srcdata += encr_secsize;
207 			dstdata += data_secsize;
208 		}
209 	} else if (bp->bio_error == EINTEGRITY) {
210 		u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
211 		int *errorp;
212 		off_t coroff, corsize, dstoff;
213 
214 		/* Sectorsize of decrypted provider eg. 4096. */
215 		decr_secsize = bp->bio_to->sectorsize;
216 		/* The real sectorsize of encrypted provider, eg. 512. */
217 		encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
218 		/* Number of data bytes in one encrypted sector, eg. 480. */
219 		data_secsize = sc->sc_data_per_sector;
220 		/* Number of sectors from decrypted provider, eg. 2. */
221 		nsec = bp->bio_length / decr_secsize;
222 		/* Number of sectors from encrypted provider, eg. 18. */
223 		nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
224 		/* Last sector number in every big sector, eg. 9. */
225 		lsec = sc->sc_bytes_per_sector / encr_secsize;
226 
227 		errorp = (int *)((char *)bp->bio_driver2 + encr_secsize * nsec);
228 		coroff = -1;
229 		corsize = 0;
230 		dstoff = bp->bio_offset;
231 
232 		for (i = 1; i <= nsec; i++) {
233 			data_secsize = sc->sc_data_per_sector;
234 			if ((i % lsec) == 0)
235 				data_secsize = decr_secsize % data_secsize;
236 			if (errorp[i - 1] == EBADMSG) {
237 				/*
238 				 * Corruption detected, remember the offset if
239 				 * this is the first corrupted sector and
240 				 * increase size.
241 				 */
242 				if (coroff == -1)
243 					coroff = dstoff;
244 				corsize += data_secsize;
245 			} else {
246 				/*
247 				 * No corruption, good.
248 				 * Report previous corruption if there was one.
249 				 */
250 				if (coroff != -1) {
251 					G_ELI_DEBUG(0, "%s: Failed to authenticate %jd "
252 					    "bytes of data at offset %jd.",
253 					    sc->sc_name, (intmax_t)corsize,
254 					    (intmax_t)coroff);
255 					coroff = -1;
256 					corsize = 0;
257 				}
258 			}
259 			dstoff += data_secsize;
260 		}
261 		/* Report previous corruption if there was one. */
262 		if (coroff != -1) {
263 			G_ELI_DEBUG(0, "%s: Failed to authenticate %jd "
264 			    "bytes of data at offset %jd.",
265 			    sc->sc_name, (intmax_t)corsize, (intmax_t)coroff);
266 		}
267 	}
268 	g_eli_free_data(bp);
269 	if (bp->bio_error != 0) {
270 		if (bp->bio_error != EINTEGRITY) {
271 			G_ELI_LOGREQ(0, bp,
272 			    "Crypto READ request failed (error=%d).",
273 			    bp->bio_error);
274 		}
275 		bp->bio_completed = 0;
276 	}
277 	/*
278 	 * Read is finished, send it up.
279 	 */
280 	g_io_deliver(bp, bp->bio_error);
281 	atomic_subtract_int(&sc->sc_inflight, 1);
282 	return (0);
283 }
284 
285 /*
286  * The function is called after data encryption.
287  *
288  * g_eli_start -> g_eli_auth_run -> G_ELI_AUTH_WRITE_DONE -> g_io_request -> g_eli_write_done -> g_io_deliver
289  */
290 static int
291 g_eli_auth_write_done(struct cryptop *crp)
292 {
293 	struct g_eli_softc *sc;
294 	struct g_consumer *cp;
295 	struct bio *bp, *cbp, *cbp2;
296 	u_int nsec;
297 
298 	if (crp->crp_etype == EAGAIN) {
299 		if (g_eli_crypto_rerun(crp) == 0)
300 			return (0);
301 	}
302 	bp = (struct bio *)crp->crp_opaque;
303 	bp->bio_inbed++;
304 	if (crp->crp_etype == 0) {
305 		G_ELI_DEBUG(3, "Crypto WRITE request done (%d/%d).",
306 		    bp->bio_inbed, bp->bio_children);
307 	} else {
308 		G_ELI_DEBUG(1, "Crypto WRITE request failed (%d/%d) error=%d.",
309 		    bp->bio_inbed, bp->bio_children, crp->crp_etype);
310 		if (bp->bio_error == 0)
311 			bp->bio_error = crp->crp_etype;
312 	}
313 	sc = bp->bio_to->geom->softc;
314 	if (crp->crp_cipher_key != NULL)
315 		g_eli_key_drop(sc, __DECONST(void *, crp->crp_cipher_key));
316 	crypto_freereq(crp);
317 	/*
318 	 * All sectors are already encrypted?
319 	 */
320 	if (bp->bio_inbed < bp->bio_children)
321 		return (0);
322 	if (bp->bio_error != 0) {
323 		G_ELI_LOGREQ(0, bp, "Crypto WRITE request failed (error=%d).",
324 		    bp->bio_error);
325 		g_eli_free_data(bp);
326 		cbp = bp->bio_driver1;
327 		bp->bio_driver1 = NULL;
328 		g_destroy_bio(cbp);
329 		g_io_deliver(bp, bp->bio_error);
330 		atomic_subtract_int(&sc->sc_inflight, 1);
331 		return (0);
332 	}
333 	cp = LIST_FIRST(&sc->sc_geom->consumer);
334 	cbp = bp->bio_driver1;
335 	bp->bio_driver1 = NULL;
336 	cbp->bio_to = cp->provider;
337 	cbp->bio_done = g_eli_write_done;
338 
339 	/* Number of sectors from decrypted provider, eg. 1. */
340 	nsec = bp->bio_length / bp->bio_to->sectorsize;
341 	/* Number of sectors from encrypted provider, eg. 9. */
342 	nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize;
343 
344 	cbp->bio_length = cp->provider->sectorsize * nsec;
345 	cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
346 	cbp->bio_data = bp->bio_driver2;
347 
348 	/*
349 	 * We write more than what is requested, so we have to be ready to write
350 	 * more than maxphys.
351 	 */
352 	cbp2 = NULL;
353 	if (cbp->bio_length > maxphys) {
354 		cbp2 = g_duplicate_bio(bp);
355 		cbp2->bio_length = cbp->bio_length - maxphys;
356 		cbp2->bio_data = cbp->bio_data + maxphys;
357 		cbp2->bio_offset = cbp->bio_offset + maxphys;
358 		cbp2->bio_to = cp->provider;
359 		cbp2->bio_done = g_eli_write_done;
360 		cbp->bio_length = maxphys;
361 	}
362 	/*
363 	 * Send encrypted data to the provider.
364 	 */
365 	G_ELI_LOGREQ(2, cbp, "Sending request.");
366 	bp->bio_inbed = 0;
367 	bp->bio_children = (cbp2 != NULL ? 2 : 1);
368 	g_io_request(cbp, cp);
369 	if (cbp2 != NULL) {
370 		G_ELI_LOGREQ(2, cbp2, "Sending request.");
371 		g_io_request(cbp2, cp);
372 	}
373 	return (0);
374 }
375 
376 void
377 g_eli_auth_read(struct g_eli_softc *sc, struct bio *bp)
378 {
379 	struct g_consumer *cp;
380 	struct bio *cbp, *cbp2;
381 	size_t size;
382 	off_t nsec;
383 
384 	G_ELI_SETWORKER(bp->bio_pflags, 0);
385 
386 	cp = LIST_FIRST(&sc->sc_geom->consumer);
387 	cbp = bp->bio_driver1;
388 	bp->bio_driver1 = NULL;
389 	cbp->bio_to = cp->provider;
390 	cbp->bio_done = g_eli_read_done;
391 
392 	/* Number of sectors from decrypted provider, eg. 1. */
393 	nsec = bp->bio_length / bp->bio_to->sectorsize;
394 	/* Number of sectors from encrypted provider, eg. 9. */
395 	nsec = (nsec * sc->sc_bytes_per_sector) / cp->provider->sectorsize;
396 
397 	cbp->bio_length = cp->provider->sectorsize * nsec;
398 	size = cbp->bio_length;
399 	size += sizeof(int) * nsec;
400 	size += G_ELI_AUTH_SECKEYLEN * nsec;
401 	cbp->bio_offset = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
402 	if (!g_eli_alloc_data(bp, size)) {
403 		G_ELI_LOGREQ(0, bp, "Crypto auth read request failed (ENOMEM)");
404 		g_destroy_bio(cbp);
405 		bp->bio_error = ENOMEM;
406 		g_io_deliver(bp, bp->bio_error);
407 		atomic_subtract_int(&sc->sc_inflight, 1);
408 		return;
409 	}
410 	cbp->bio_data = bp->bio_driver2;
411 
412 	/* Clear the error array. */
413 	memset((char *)bp->bio_driver2 + cbp->bio_length, 0,
414 	    sizeof(int) * nsec);
415 
416 	/*
417 	 * We read more than what is requested, so we have to be ready to read
418 	 * more than maxphys.
419 	 */
420 	cbp2 = NULL;
421 	if (cbp->bio_length > maxphys) {
422 		cbp2 = g_duplicate_bio(bp);
423 		cbp2->bio_length = cbp->bio_length - maxphys;
424 		cbp2->bio_data = cbp->bio_data + maxphys;
425 		cbp2->bio_offset = cbp->bio_offset + maxphys;
426 		cbp2->bio_to = cp->provider;
427 		cbp2->bio_done = g_eli_read_done;
428 		cbp->bio_length = maxphys;
429 	}
430 	/*
431 	 * Read encrypted data from provider.
432 	 */
433 	G_ELI_LOGREQ(2, cbp, "Sending request.");
434 	g_io_request(cbp, cp);
435 	if (cbp2 != NULL) {
436 		G_ELI_LOGREQ(2, cbp2, "Sending request.");
437 		g_io_request(cbp2, cp);
438 	}
439 }
440 
441 /*
442  * This is the main function responsible for cryptography (ie. communication
443  * with crypto(9) subsystem).
444  *
445  * BIO_READ:
446  *	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
447  * BIO_WRITE:
448  *	g_eli_start -> G_ELI_AUTH_RUN -> g_eli_auth_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver
449  */
450 void
451 g_eli_auth_run(struct g_eli_worker *wr, struct bio *bp)
452 {
453 	struct g_eli_softc *sc;
454 	struct cryptopq crpq;
455 	struct cryptop *crp;
456 	u_int i, lsec, nsec, data_secsize, decr_secsize, encr_secsize;
457 	off_t dstoff;
458 	u_char *p, *data, *authkey, *plaindata;
459 	int error __diagused;
460 	bool batch;
461 
462 	G_ELI_LOGREQ(3, bp, "%s", __func__);
463 
464 	G_ELI_SETWORKER(bp->bio_pflags, wr->w_number);
465 	sc = wr->w_softc;
466 	/* Sectorsize of decrypted provider eg. 4096. */
467 	decr_secsize = bp->bio_to->sectorsize;
468 	/* The real sectorsize of encrypted provider, eg. 512. */
469 	encr_secsize = LIST_FIRST(&sc->sc_geom->consumer)->provider->sectorsize;
470 	/* Number of data bytes in one encrypted sector, eg. 480. */
471 	data_secsize = sc->sc_data_per_sector;
472 	/* Number of sectors from decrypted provider, eg. 2. */
473 	nsec = bp->bio_length / decr_secsize;
474 	/* Number of sectors from encrypted provider, eg. 18. */
475 	nsec = (nsec * sc->sc_bytes_per_sector) / encr_secsize;
476 	/* Last sector number in every big sector, eg. 9. */
477 	lsec = sc->sc_bytes_per_sector / encr_secsize;
478 	/* Destination offset, used for IV generation. */
479 	dstoff = (bp->bio_offset / bp->bio_to->sectorsize) * sc->sc_bytes_per_sector;
480 
481 	plaindata = bp->bio_data;
482 	if (bp->bio_cmd == BIO_READ) {
483 		data = bp->bio_driver2;
484 		p = data + encr_secsize * nsec;
485 		p += sizeof(int) * nsec;
486 	} else {
487 		size_t size;
488 
489 		size = encr_secsize * nsec;
490 		size += G_ELI_AUTH_SECKEYLEN * nsec;
491 		size += sizeof(uintptr_t);	/* Space for alignment. */
492 		if (!g_eli_alloc_data(bp, size)) {
493 			G_ELI_LOGREQ(0, bp, "Crypto request failed (ENOMEM)");
494 			if (bp->bio_driver1 != NULL) {
495 				g_destroy_bio(bp->bio_driver1);
496 				bp->bio_driver1 = NULL;
497 			}
498 			bp->bio_error = ENOMEM;
499 			g_io_deliver(bp, bp->bio_error);
500 			if (sc != NULL)
501 				atomic_subtract_int(&sc->sc_inflight, 1);
502 			return;
503 		}
504 		data = bp->bio_driver2;
505 		p = data + encr_secsize * nsec;
506 	}
507 	bp->bio_inbed = 0;
508 	bp->bio_children = nsec;
509 
510 #if defined(__mips_n64) || defined(__mips_o64)
511 	p = (char *)roundup((uintptr_t)p, sizeof(uintptr_t));
512 #endif
513 
514 	TAILQ_INIT(&crpq);
515 	batch = atomic_load_int(&g_eli_batch) != 0;
516 
517 	for (i = 1; i <= nsec; i++, dstoff += encr_secsize) {
518 		crp = crypto_getreq(wr->w_sid, M_WAITOK);
519 		authkey = (u_char *)p;		p += G_ELI_AUTH_SECKEYLEN;
520 
521 		data_secsize = sc->sc_data_per_sector;
522 		if ((i % lsec) == 0) {
523 			data_secsize = decr_secsize % data_secsize;
524 			/*
525 			 * Last encrypted sector of each decrypted sector is
526 			 * only partially filled.
527 			 */
528 			if (bp->bio_cmd == BIO_WRITE)
529 				memset(data + sc->sc_alen + data_secsize, 0,
530 				    encr_secsize - sc->sc_alen - data_secsize);
531 		} else if (data_secsize + sc->sc_alen != encr_secsize) {
532 			/*
533 			 * If the HMAC size is not a multiple of 128 bits, the
534 			 * per-sector data size is rounded down to ensure that
535 			 * encryption can be performed without requiring any
536 			 * padding.  In this case, each sector contains unused
537 			 * bytes.
538 			 */
539 			if (bp->bio_cmd == BIO_WRITE)
540 				memset(data + sc->sc_alen + data_secsize, 0,
541 				    encr_secsize - sc->sc_alen - data_secsize);
542 		}
543 
544 		if (bp->bio_cmd == BIO_WRITE) {
545 			bcopy(plaindata, data + sc->sc_alen, data_secsize);
546 			plaindata += data_secsize;
547 		}
548 
549 		crypto_use_buf(crp, data, sc->sc_alen + data_secsize);
550 		crp->crp_opaque = (void *)bp;
551 		data += encr_secsize;
552 		crp->crp_flags = CRYPTO_F_CBIFSYNC;
553 		if (bp->bio_cmd == BIO_WRITE) {
554 			crp->crp_callback = g_eli_auth_write_done;
555 			crp->crp_op = CRYPTO_OP_ENCRYPT |
556 			    CRYPTO_OP_COMPUTE_DIGEST;
557 		} else {
558 			crp->crp_callback = g_eli_auth_read_done;
559 			crp->crp_op = CRYPTO_OP_DECRYPT |
560 			    CRYPTO_OP_VERIFY_DIGEST;
561 		}
562 
563 		crp->crp_digest_start = 0;
564 		crp->crp_payload_start = sc->sc_alen;
565 		crp->crp_payload_length = data_secsize;
566 		if ((sc->sc_flags & G_ELI_FLAG_FIRST_KEY) == 0) {
567 			crp->crp_cipher_key = g_eli_key_hold(sc, dstoff,
568 			    encr_secsize);
569 		}
570 		if (g_eli_ivlen(sc->sc_ealgo) != 0) {
571 			crp->crp_flags |= CRYPTO_F_IV_SEPARATE;
572 			g_eli_crypto_ivgen(sc, dstoff, crp->crp_iv,
573 			    sizeof(crp->crp_iv));
574 		}
575 
576 		g_eli_auth_keygen(sc, dstoff, authkey);
577 		crp->crp_auth_key = authkey;
578 
579 		if (batch) {
580 			TAILQ_INSERT_TAIL(&crpq, crp, crp_next);
581 		} else {
582 			error = crypto_dispatch(crp);
583 			KASSERT(error == 0,
584 			    ("crypto_dispatch() failed (error=%d)", error));
585 		}
586 	}
587 
588 	if (batch)
589 		crypto_dispatch_batch(&crpq, 0);
590 }
591