xref: /netbsd-src/sys/dev/cgd.c (revision 267197ec1eebfcb9810ea27a89625b6ddf68e3e7)
1 /* $NetBSD: cgd.c,v 1.50 2008/01/04 21:17:46 ad Exp $ */
2 
3 /*-
4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Roland C. Dowdeswell.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 __KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.50 2008/01/04 21:17:46 ad Exp $");
41 
42 #include <sys/types.h>
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/proc.h>
46 #include <sys/errno.h>
47 #include <sys/buf.h>
48 #include <sys/bufq.h>
49 #include <sys/malloc.h>
50 #include <sys/pool.h>
51 #include <sys/ioctl.h>
52 #include <sys/device.h>
53 #include <sys/disk.h>
54 #include <sys/disklabel.h>
55 #include <sys/fcntl.h>
56 #include <sys/vnode.h>
57 #include <sys/conf.h>
58 
59 #include <dev/dkvar.h>
60 #include <dev/cgdvar.h>
61 
62 /* Entry Point Functions */
63 
64 void	cgdattach(int);
65 
66 static dev_type_open(cgdopen);
67 static dev_type_close(cgdclose);
68 static dev_type_read(cgdread);
69 static dev_type_write(cgdwrite);
70 static dev_type_ioctl(cgdioctl);
71 static dev_type_strategy(cgdstrategy);
72 static dev_type_dump(cgddump);
73 static dev_type_size(cgdsize);
74 
75 const struct bdevsw cgd_bdevsw = {
76 	cgdopen, cgdclose, cgdstrategy, cgdioctl,
77 	cgddump, cgdsize, D_DISK
78 };
79 
80 const struct cdevsw cgd_cdevsw = {
81 	cgdopen, cgdclose, cgdread, cgdwrite, cgdioctl,
82 	nostop, notty, nopoll, nommap, nokqfilter, D_DISK
83 };
84 
85 /* Internal Functions */
86 
87 static int	cgdstart(struct dk_softc *, struct buf *);
88 static void	cgdiodone(struct buf *);
89 
90 static int	cgd_ioctl_set(struct cgd_softc *, void *, struct lwp *);
91 static int	cgd_ioctl_clr(struct cgd_softc *, void *, struct lwp *);
92 static int	cgdinit(struct cgd_softc *, const char *, struct vnode *,
93 			struct lwp *);
94 static void	cgd_cipher(struct cgd_softc *, void *, void *,
95 			   size_t, daddr_t, size_t, int);
96 
97 /* Pseudo-disk Interface */
98 
99 static struct dk_intf the_dkintf = {
100 	DTYPE_CGD,
101 	"cgd",
102 	cgdopen,
103 	cgdclose,
104 	cgdstrategy,
105 	cgdstart,
106 };
107 static struct dk_intf *di = &the_dkintf;
108 
109 static struct dkdriver cgddkdriver = {
110 	.d_strategy = cgdstrategy,
111 	.d_minphys = minphys,
112 };
113 
114 /* DIAGNOSTIC and DEBUG definitions */
115 
116 #if defined(CGDDEBUG) && !defined(DEBUG)
117 #define DEBUG
118 #endif
119 
120 #ifdef DEBUG
121 int cgddebug = 0;
122 
123 #define CGDB_FOLLOW	0x1
124 #define CGDB_IO	0x2
125 #define CGDB_CRYPTO	0x4
126 
127 #define IFDEBUG(x,y)		if (cgddebug & (x)) y
128 #define DPRINTF(x,y)		IFDEBUG(x, printf y)
129 #define DPRINTF_FOLLOW(y)	DPRINTF(CGDB_FOLLOW, y)
130 
131 static void	hexprint(const char *, void *, int);
132 
133 #else
134 #define IFDEBUG(x,y)
135 #define DPRINTF(x,y)
136 #define DPRINTF_FOLLOW(y)
137 #endif
138 
139 #ifdef DIAGNOSTIC
140 #define DIAGPANIC(x)		panic x
141 #define DIAGCONDPANIC(x,y)	if (x) panic y
142 #else
143 #define DIAGPANIC(x)
144 #define DIAGCONDPANIC(x,y)
145 #endif
146 
147 /* Global variables */
148 
149 struct	cgd_softc *cgd_softc;
150 int	numcgd = 0;
151 
152 /* Utility Functions */
153 
154 #define CGDUNIT(x)		DISKUNIT(x)
155 #define GETCGD_SOFTC(_cs, x)	if (!((_cs) = getcgd_softc(x))) return ENXIO
156 
157 static struct cgd_softc *
158 getcgd_softc(dev_t dev)
159 {
160 	int	unit = CGDUNIT(dev);
161 
162 	DPRINTF_FOLLOW(("getcgd_softc(0x%x): unit = %d\n", dev, unit));
163 	if (unit >= numcgd)
164 		return NULL;
165 	return &cgd_softc[unit];
166 }
167 
168 /* The code */
169 
170 static void
171 cgdsoftc_init(struct cgd_softc *cs, int num)
172 {
173 	char	sbuf[DK_XNAME_SIZE];
174 
175 	memset(cs, 0x0, sizeof(*cs));
176 	snprintf(sbuf, DK_XNAME_SIZE, "cgd%d", num);
177 	simple_lock_init(&cs->sc_slock);
178 	dk_sc_init(&cs->sc_dksc, cs, sbuf);
179 	disk_init(&cs->sc_dksc.sc_dkdev, cs->sc_dksc.sc_xname, &cgddkdriver);
180 }
181 
182 void
183 cgdattach(int num)
184 {
185 	int	i;
186 
187 	DPRINTF_FOLLOW(("cgdattach(%d)\n", num));
188 	if (num <= 0) {
189 		DIAGPANIC(("cgdattach: count <= 0"));
190 		return;
191 	}
192 
193 	cgd_softc = (void *)malloc(num * sizeof(*cgd_softc), M_DEVBUF, M_NOWAIT);
194 	if (!cgd_softc) {
195 		printf("WARNING: unable to malloc(9) memory for crypt disks\n");
196 		DIAGPANIC(("cgdattach: cannot malloc(9) enough memory"));
197 		return;
198 	}
199 
200 	numcgd = num;
201 	for (i=0; i<num; i++)
202 		cgdsoftc_init(&cgd_softc[i], i);
203 }
204 
205 static int
206 cgdopen(dev_t dev, int flags, int fmt, struct lwp *l)
207 {
208 	struct	cgd_softc *cs;
209 
210 	DPRINTF_FOLLOW(("cgdopen(%d, %d)\n", dev, flags));
211 	GETCGD_SOFTC(cs, dev);
212 	return dk_open(di, &cs->sc_dksc, dev, flags, fmt, l);
213 }
214 
215 static int
216 cgdclose(dev_t dev, int flags, int fmt, struct lwp *l)
217 {
218 	struct	cgd_softc *cs;
219 
220 	DPRINTF_FOLLOW(("cgdclose(%d, %d)\n", dev, flags));
221 	GETCGD_SOFTC(cs, dev);
222 	return dk_close(di, &cs->sc_dksc, dev, flags, fmt, l);
223 }
224 
225 static void
226 cgdstrategy(struct buf *bp)
227 {
228 	struct	cgd_softc *cs = getcgd_softc(bp->b_dev);
229 
230 	DPRINTF_FOLLOW(("cgdstrategy(%p): b_bcount = %ld\n", bp,
231 	    (long)bp->b_bcount));
232 	/* XXXrcd: Should we test for (cs != NULL)? */
233 	dk_strategy(di, &cs->sc_dksc, bp);
234 	return;
235 }
236 
237 static int
238 cgdsize(dev_t dev)
239 {
240 	struct cgd_softc *cs = getcgd_softc(dev);
241 
242 	DPRINTF_FOLLOW(("cgdsize(%d)\n", dev));
243 	if (!cs)
244 		return -1;
245 	return dk_size(di, &cs->sc_dksc, dev);
246 }
247 
248 /*
249  * cgd_{get,put}data are functions that deal with getting a buffer
250  * for the new encrypted data.  We have a buffer per device so that
251  * we can ensure that we can always have a transaction in flight.
252  * We use this buffer first so that we have one less piece of
253  * malloc'ed data at any given point.
254  */
255 
256 static void *
257 cgd_getdata(struct dk_softc *dksc, unsigned long size)
258 {
259 	struct	cgd_softc *cs =dksc->sc_osc;
260 	void *	data = NULL;
261 
262 	simple_lock(&cs->sc_slock);
263 	if (cs->sc_data_used == 0) {
264 		cs->sc_data_used = 1;
265 		data = cs->sc_data;
266 	}
267 	simple_unlock(&cs->sc_slock);
268 
269 	if (data)
270 		return data;
271 
272 	return malloc(size, M_DEVBUF, M_NOWAIT);
273 }
274 
275 static void
276 cgd_putdata(struct dk_softc *dksc, void *data)
277 {
278 	struct	cgd_softc *cs =dksc->sc_osc;
279 
280 	if (data == cs->sc_data) {
281 		simple_lock(&cs->sc_slock);
282 		cs->sc_data_used = 0;
283 		simple_unlock(&cs->sc_slock);
284 	} else {
285 		free(data, M_DEVBUF);
286 	}
287 }
288 
289 static int
290 cgdstart(struct dk_softc *dksc, struct buf *bp)
291 {
292 	struct	cgd_softc *cs = dksc->sc_osc;
293 	struct	buf *nbp;
294 	void *	addr;
295 	void *	newaddr;
296 	daddr_t	bn;
297 	struct	vnode *vp;
298 
299 	DPRINTF_FOLLOW(("cgdstart(%p, %p)\n", dksc, bp));
300 	disk_busy(&dksc->sc_dkdev); /* XXX: put in dksubr.c */
301 
302 	bn = bp->b_rawblkno;
303 
304 	/*
305 	 * We attempt to allocate all of our resources up front, so that
306 	 * we can fail quickly if they are unavailable.
307 	 */
308 
309 	nbp = getiobuf(cs->sc_tvn, false);
310 	if (nbp == NULL) {
311 		disk_unbusy(&dksc->sc_dkdev, 0, (bp->b_flags & B_READ));
312 		return -1;
313 	}
314 
315 	/*
316 	 * If we are writing, then we need to encrypt the outgoing
317 	 * block into a new block of memory.  If we fail, then we
318 	 * return an error and let the dksubr framework deal with it.
319 	 */
320 	newaddr = addr = bp->b_data;
321 	if ((bp->b_flags & B_READ) == 0) {
322 		newaddr = cgd_getdata(dksc, bp->b_bcount);
323 		if (!newaddr) {
324 			putiobuf(nbp);
325 			disk_unbusy(&dksc->sc_dkdev, 0, (bp->b_flags & B_READ));
326 			return -1;
327 		}
328 		cgd_cipher(cs, newaddr, addr, bp->b_bcount, bn,
329 		    DEV_BSIZE, CGD_CIPHER_ENCRYPT);
330 	}
331 
332 	nbp->b_data = newaddr;
333 	nbp->b_flags = bp->b_flags;
334 	nbp->b_oflags = bp->b_oflags;
335 	nbp->b_cflags = bp->b_cflags;
336 	nbp->b_iodone = cgdiodone;
337 	nbp->b_proc = bp->b_proc;
338 	nbp->b_blkno = bn;
339 	nbp->b_bcount = bp->b_bcount;
340 	nbp->b_private = bp;
341 
342 	BIO_COPYPRIO(nbp, bp);
343 
344 	if ((nbp->b_flags & B_READ) == 0) {
345 		vp = nbp->b_vp;
346 		mutex_enter(&vp->v_interlock);
347 		vp->v_numoutput++;
348 		mutex_exit(&vp->v_interlock);
349 	}
350 	VOP_STRATEGY(cs->sc_tvn, nbp);
351 	return 0;
352 }
353 
354 /* expected to be called at splbio() */
355 static void
356 cgdiodone(struct buf *nbp)
357 {
358 	struct	buf *obp = nbp->b_private;
359 	struct	cgd_softc *cs = getcgd_softc(obp->b_dev);
360 	struct	dk_softc *dksc = &cs->sc_dksc;
361 
362 	KDASSERT(cs);
363 
364 	DPRINTF_FOLLOW(("cgdiodone(%p)\n", nbp));
365 	DPRINTF(CGDB_IO, ("cgdiodone: bp %p bcount %d resid %d\n",
366 	    obp, obp->b_bcount, obp->b_resid));
367 	DPRINTF(CGDB_IO, (" dev 0x%x, nbp %p bn %" PRId64 " addr %p bcnt %d\n",
368 	    nbp->b_dev, nbp, nbp->b_blkno, nbp->b_data,
369 	    nbp->b_bcount));
370 	if (nbp->b_error != 0) {
371 		obp->b_error = nbp->b_error;
372 		printf("%s: error %d\n", dksc->sc_xname, obp->b_error);
373 	}
374 
375 	/* Perform the decryption if we are reading.
376 	 *
377 	 * Note: use the blocknumber from nbp, since it is what
378 	 *       we used to encrypt the blocks.
379 	 */
380 
381 	if (nbp->b_flags & B_READ)
382 		cgd_cipher(cs, obp->b_data, obp->b_data, obp->b_bcount,
383 		    nbp->b_blkno, DEV_BSIZE, CGD_CIPHER_DECRYPT);
384 
385 	/* If we allocated memory, free it now... */
386 	if (nbp->b_data != obp->b_data)
387 		cgd_putdata(dksc, nbp->b_data);
388 
389 	putiobuf(nbp);
390 
391 	/* Request is complete for whatever reason */
392 	obp->b_resid = 0;
393 	if (obp->b_error != 0)
394 		obp->b_resid = obp->b_bcount;
395 	disk_unbusy(&dksc->sc_dkdev, obp->b_bcount - obp->b_resid,
396 	    (obp->b_flags & B_READ));
397 	biodone(obp);
398 	dk_iodone(di, dksc);
399 }
400 
401 /* XXX: we should probably put these into dksubr.c, mostly */
402 static int
403 cgdread(dev_t dev, struct uio *uio, int flags)
404 {
405 	struct	cgd_softc *cs;
406 	struct	dk_softc *dksc;
407 
408 	DPRINTF_FOLLOW(("cgdread(%d, %p, %d)\n", dev, uio, flags));
409 	GETCGD_SOFTC(cs, dev);
410 	dksc = &cs->sc_dksc;
411 	if ((dksc->sc_flags & DKF_INITED) == 0)
412 		return ENXIO;
413 	return physio(cgdstrategy, NULL, dev, B_READ, minphys, uio);
414 }
415 
416 /* XXX: we should probably put these into dksubr.c, mostly */
417 static int
418 cgdwrite(dev_t dev, struct uio *uio, int flags)
419 {
420 	struct	cgd_softc *cs;
421 	struct	dk_softc *dksc;
422 
423 	DPRINTF_FOLLOW(("cgdwrite(%d, %p, %d)\n", dev, uio, flags));
424 	GETCGD_SOFTC(cs, dev);
425 	dksc = &cs->sc_dksc;
426 	if ((dksc->sc_flags & DKF_INITED) == 0)
427 		return ENXIO;
428 	return physio(cgdstrategy, NULL, dev, B_WRITE, minphys, uio);
429 }
430 
431 static int
432 cgdioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
433 {
434 	struct	cgd_softc *cs;
435 	struct	dk_softc *dksc;
436 	struct	disk *dk;
437 	int	ret;
438 	int	part = DISKPART(dev);
439 	int	pmask = 1 << part;
440 
441 	DPRINTF_FOLLOW(("cgdioctl(%d, %ld, %p, %d, %p)\n",
442 	    dev, cmd, data, flag, l));
443 	GETCGD_SOFTC(cs, dev);
444 	dksc = &cs->sc_dksc;
445 	dk = &dksc->sc_dkdev;
446 	switch (cmd) {
447 	case CGDIOCSET:
448 	case CGDIOCCLR:
449 		if ((flag & FWRITE) == 0)
450 			return EBADF;
451 	}
452 
453 	switch (cmd) {
454 	case CGDIOCSET:
455 		if (dksc->sc_flags & DKF_INITED)
456 			ret = EBUSY;
457 		else
458 			ret = cgd_ioctl_set(cs, data, l);
459 		break;
460 	case CGDIOCCLR:
461 		if (!(dksc->sc_flags & DKF_INITED)) {
462 			ret = ENXIO;
463 			break;
464 		}
465 		if (DK_BUSY(&cs->sc_dksc, pmask)) {
466 			ret = EBUSY;
467 			break;
468 		}
469 		ret = cgd_ioctl_clr(cs, data, l);
470 		break;
471 	default:
472 		ret = dk_ioctl(di, dksc, dev, cmd, data, flag, l);
473 		break;
474 	}
475 
476 	return ret;
477 }
478 
479 static int
480 cgddump(dev_t dev, daddr_t blkno, void *va, size_t size)
481 {
482 	struct	cgd_softc *cs;
483 
484 	DPRINTF_FOLLOW(("cgddump(%d, %" PRId64 ", %p, %lu)\n", dev, blkno, va,
485 	    (unsigned long)size));
486 	GETCGD_SOFTC(cs, dev);
487 	return dk_dump(di, &cs->sc_dksc, dev, blkno, va, size);
488 }
489 
490 /*
491  * XXXrcd:
492  *  for now we hardcode the maximum key length.
493  */
494 #define MAX_KEYSIZE	1024
495 
496 /* ARGSUSED */
497 static int
498 cgd_ioctl_set(struct cgd_softc *cs, void *data, struct lwp *l)
499 {
500 	struct	 cgd_ioctl *ci = data;
501 	struct	 vnode *vp;
502 	int	 ret;
503 	size_t	 keybytes;			/* key length in bytes */
504 	const char *cp;
505 	char	 *inbuf;
506 
507 	cp = ci->ci_disk;
508 	if ((ret = dk_lookup(cp, l, &vp, UIO_USERSPACE)) != 0)
509 		return ret;
510 
511 	inbuf = malloc(MAX_KEYSIZE, M_TEMP, M_WAITOK);
512 
513 	if ((ret = cgdinit(cs, cp, vp, l)) != 0)
514 		goto bail;
515 
516 	(void)memset(inbuf, 0, MAX_KEYSIZE);
517 	ret = copyinstr(ci->ci_alg, inbuf, 256, NULL);
518 	if (ret)
519 		goto bail;
520 	cs->sc_cfuncs = cryptfuncs_find(inbuf);
521 	if (!cs->sc_cfuncs) {
522 		ret = EINVAL;
523 		goto bail;
524 	}
525 
526 	/* right now we only support encblkno, so hard-code it */
527 	(void)memset(inbuf, 0, MAX_KEYSIZE);
528 	ret = copyinstr(ci->ci_ivmethod, inbuf, MAX_KEYSIZE, NULL);
529 	if (ret)
530 		goto bail;
531 	if (strcmp("encblkno", inbuf)) {
532 		ret = EINVAL;
533 		goto bail;
534 	}
535 
536 	keybytes = ci->ci_keylen / 8 + 1;
537 	if (keybytes > MAX_KEYSIZE) {
538 		ret = EINVAL;
539 		goto bail;
540 	}
541 	(void)memset(inbuf, 0, MAX_KEYSIZE);
542 	ret = copyin(ci->ci_key, inbuf, keybytes);
543 	if (ret)
544 		goto bail;
545 
546 	cs->sc_cdata.cf_blocksize = ci->ci_blocksize;
547 	cs->sc_cdata.cf_mode = CGD_CIPHER_CBC_ENCBLKNO;
548 	cs->sc_cdata.cf_priv = cs->sc_cfuncs->cf_init(ci->ci_keylen, inbuf,
549 	    &cs->sc_cdata.cf_blocksize);
550 	(void)memset(inbuf, 0, MAX_KEYSIZE);
551 	if (!cs->sc_cdata.cf_priv) {
552 		printf("cgd: unable to initialize cipher\n");
553 		ret = EINVAL;		/* XXX is this the right error? */
554 		goto bail;
555 	}
556 	free(inbuf, M_TEMP);
557 
558 	bufq_alloc(&cs->sc_dksc.sc_bufq, "fcfs", 0);
559 
560 	cs->sc_data = malloc(MAXPHYS, M_DEVBUF, M_WAITOK);
561 	cs->sc_data_used = 0;
562 
563 	cs->sc_dksc.sc_flags |= DKF_INITED;
564 
565 	/* Attach the disk. */
566 	disk_attach(&cs->sc_dksc.sc_dkdev);
567 
568 	/* Try and read the disklabel. */
569 	dk_getdisklabel(di, &cs->sc_dksc, 0 /* XXX ? */);
570 
571 	/* Discover wedges on this disk. */
572 	dkwedge_discover(&cs->sc_dksc.sc_dkdev);
573 
574 	return 0;
575 
576 bail:
577 	free(inbuf, M_TEMP);
578 	(void)vn_close(vp, FREAD|FWRITE, l->l_cred, l);
579 	return ret;
580 }
581 
582 /* ARGSUSED */
583 static int
584 cgd_ioctl_clr(struct cgd_softc *cs, void *data, struct lwp *l)
585 {
586 	int	s;
587 
588 	/* Delete all of our wedges. */
589 	dkwedge_delall(&cs->sc_dksc.sc_dkdev);
590 
591 	/* Kill off any queued buffers. */
592 	s = splbio();
593 	bufq_drain(cs->sc_dksc.sc_bufq);
594 	splx(s);
595 	bufq_free(cs->sc_dksc.sc_bufq);
596 
597 	(void)vn_close(cs->sc_tvn, FREAD|FWRITE, l->l_cred, l);
598 	cs->sc_cfuncs->cf_destroy(cs->sc_cdata.cf_priv);
599 	free(cs->sc_tpath, M_DEVBUF);
600 	free(cs->sc_data, M_DEVBUF);
601 	cs->sc_data_used = 0;
602 	cs->sc_dksc.sc_flags &= ~DKF_INITED;
603 	disk_detach(&cs->sc_dksc.sc_dkdev);
604 
605 	return 0;
606 }
607 
608 static int
609 cgdinit(struct cgd_softc *cs, const char *cpath, struct vnode *vp,
610 	struct lwp *l)
611 {
612 	struct	dk_geom *pdg;
613 	struct	partinfo dpart;
614 	struct	vattr va;
615 	size_t	size;
616 	int	maxsecsize = 0;
617 	int	ret;
618 	char	*tmppath;
619 
620 	cs->sc_dksc.sc_size = 0;
621 	cs->sc_tvn = vp;
622 	cs->sc_tpath = NULL;
623 
624 	tmppath = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
625 	ret = copyinstr(cpath, tmppath, MAXPATHLEN, &cs->sc_tpathlen);
626 	if (ret)
627 		goto bail;
628 	cs->sc_tpath = malloc(cs->sc_tpathlen, M_DEVBUF, M_WAITOK);
629 	memcpy(cs->sc_tpath, tmppath, cs->sc_tpathlen);
630 
631 	if ((ret = VOP_GETATTR(vp, &va, l->l_cred)) != 0)
632 		goto bail;
633 
634 	cs->sc_tdev = va.va_rdev;
635 
636 	ret = VOP_IOCTL(vp, DIOCGPART, &dpart, FREAD, l->l_cred);
637 	if (ret)
638 		goto bail;
639 
640 	maxsecsize =
641 	    ((dpart.disklab->d_secsize > maxsecsize) ?
642 	    dpart.disklab->d_secsize : maxsecsize);
643 	size = dpart.part->p_size;
644 
645 	if (!size) {
646 		ret = ENODEV;
647 		goto bail;
648 	}
649 
650 	cs->sc_dksc.sc_size = size;
651 
652 	/*
653 	 * XXX here we should probe the underlying device.  If we
654 	 *     are accessing a partition of type RAW_PART, then
655 	 *     we should populate our initial geometry with the
656 	 *     geometry that we discover from the device.
657 	 */
658 	pdg = &cs->sc_dksc.sc_geom;
659 	pdg->pdg_secsize = DEV_BSIZE;
660 	pdg->pdg_ntracks = 1;
661 	pdg->pdg_nsectors = 1024 * (1024 / pdg->pdg_secsize);
662 	pdg->pdg_ncylinders = cs->sc_dksc.sc_size / pdg->pdg_nsectors;
663 
664 bail:
665 	free(tmppath, M_TEMP);
666 	if (ret && cs->sc_tpath)
667 		free(cs->sc_tpath, M_DEVBUF);
668 	return ret;
669 }
670 
671 /*
672  * Our generic cipher entry point.  This takes care of the
673  * IV mode and passes off the work to the specific cipher.
674  * We implement here the IV method ``encrypted block
675  * number''.
676  *
677  * For the encryption case, we accomplish this by setting
678  * up a struct uio where the first iovec of the source is
679  * the blocknumber and the first iovec of the dest is a
680  * sink.  We then call the cipher with an IV of zero, and
681  * the right thing happens.
682  *
683  * For the decryption case, we use the same basic mechanism
684  * for symmetry, but we encrypt the block number in the
685  * first iovec.
686  *
687  * We mainly do this to avoid requiring the definition of
688  * an ECB mode.
689  *
690  * XXXrcd: for now we rely on our own crypto framework defined
691  *         in dev/cgd_crypto.c.  This will change when we
692  *         get a generic kernel crypto framework.
693  */
694 
695 static void
696 blkno2blkno_buf(char *sbuf, daddr_t blkno)
697 {
698 	int	i;
699 
700 	/* Set up the blkno in blkno_buf, here we do not care much
701 	 * about the final layout of the information as long as we
702 	 * can guarantee that each sector will have a different IV
703 	 * and that the endianness of the machine will not affect
704 	 * the representation that we have chosen.
705 	 *
706 	 * We choose this representation, because it does not rely
707 	 * on the size of buf (which is the blocksize of the cipher),
708 	 * but allows daddr_t to grow without breaking existing
709 	 * disks.
710 	 *
711 	 * Note that blkno2blkno_buf does not take a size as input,
712 	 * and hence must be called on a pre-zeroed buffer of length
713 	 * greater than or equal to sizeof(daddr_t).
714 	 */
715 	for (i=0; i < sizeof(daddr_t); i++) {
716 		*sbuf++ = blkno & 0xff;
717 		blkno >>= 8;
718 	}
719 }
720 
721 static void
722 cgd_cipher(struct cgd_softc *cs, void *dstv, void *srcv,
723     size_t len, daddr_t blkno, size_t secsize, int dir)
724 {
725 	char		*dst = dstv;
726 	char 		*src = srcv;
727 	cfunc_cipher	*cipher = cs->sc_cfuncs->cf_cipher;
728 	struct uio	dstuio;
729 	struct uio	srcuio;
730 	struct iovec	dstiov[2];
731 	struct iovec	srciov[2];
732 	size_t		blocksize = cs->sc_cdata.cf_blocksize;
733 	char		sink[blocksize];
734 	char		zero_iv[blocksize];
735 	char		blkno_buf[blocksize];
736 
737 	DPRINTF_FOLLOW(("cgd_cipher() dir=%d\n", dir));
738 
739 	DIAGCONDPANIC(len % blocksize != 0,
740 	    ("cgd_cipher: len %% blocksize != 0"));
741 
742 	/* ensure that sizeof(daddr_t) <= blocksize (for encblkno IVing) */
743 	DIAGCONDPANIC(sizeof(daddr_t) > blocksize,
744 	    ("cgd_cipher: sizeof(daddr_t) > blocksize"));
745 
746 	memset(zero_iv, 0x0, sizeof(zero_iv));
747 
748 	dstuio.uio_iov = dstiov;
749 	dstuio.uio_iovcnt = 2;
750 
751 	srcuio.uio_iov = srciov;
752 	srcuio.uio_iovcnt = 2;
753 
754 	dstiov[0].iov_base = sink;
755 	dstiov[0].iov_len  = blocksize;
756 	srciov[0].iov_base = blkno_buf;
757 	srciov[0].iov_len  = blocksize;
758 	dstiov[1].iov_len  = secsize;
759 	srciov[1].iov_len  = secsize;
760 
761 	for (; len > 0; len -= secsize) {
762 		dstiov[1].iov_base = dst;
763 		srciov[1].iov_base = src;
764 
765 		memset(blkno_buf, 0x0, sizeof(blkno_buf));
766 		blkno2blkno_buf(blkno_buf, blkno);
767 		if (dir == CGD_CIPHER_DECRYPT) {
768 			dstuio.uio_iovcnt = 1;
769 			srcuio.uio_iovcnt = 1;
770 			IFDEBUG(CGDB_CRYPTO, hexprint("step 0: blkno_buf",
771 			    blkno_buf, sizeof(blkno_buf)));
772 			cipher(cs->sc_cdata.cf_priv, &dstuio, &srcuio,
773 			    zero_iv, CGD_CIPHER_ENCRYPT);
774 			memcpy(blkno_buf, sink, blocksize);
775 			dstuio.uio_iovcnt = 2;
776 			srcuio.uio_iovcnt = 2;
777 		}
778 
779 		IFDEBUG(CGDB_CRYPTO, hexprint("step 1: blkno_buf",
780 		    blkno_buf, sizeof(blkno_buf)));
781 		cipher(cs->sc_cdata.cf_priv, &dstuio, &srcuio, zero_iv, dir);
782 		IFDEBUG(CGDB_CRYPTO, hexprint("step 2: sink",
783 		    sink, sizeof(sink)));
784 
785 		dst += secsize;
786 		src += secsize;
787 		blkno++;
788 	}
789 }
790 
791 #ifdef DEBUG
792 static void
793 hexprint(const char *start, void *buf, int len)
794 {
795 	char	*c = buf;
796 
797 	DIAGCONDPANIC(len < 0, ("hexprint: called with len < 0"));
798 	printf("%s: len=%06d 0x", start, len);
799 	while (len--)
800 		printf("%02x", (unsigned char) *c++);
801 }
802 #endif
803