xref: /openbsd-src/sys/dev/vnd.c (revision 3374c67d44f9b75b98444cbf63020f777792342e)
1 /*	$OpenBSD: vnd.c,v 1.179 2022/10/23 14:39:19 krw Exp $	*/
2 /*	$NetBSD: vnd.c,v 1.26 1996/03/30 23:06:11 christos Exp $	*/
3 
4 /*
5  * Copyright (c) 1988 University of Utah.
6  * Copyright (c) 1990, 1993
7  *	The Regents of the University of California.  All rights reserved.
8  *
9  * This code is derived from software contributed to Berkeley by
10  * the Systems Programming Group of the University of Utah Computer
11  * Science Department.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  */
37 
38 /*
39  * There is a security issue involved with this driver.
40  *
41  * Once mounted all access to the contents of the "mapped" file via
42  * the special file is controlled by the permissions on the special
43  * file, the protection of the mapped file is ignored (effectively,
44  * by using root credentials in all transactions).
45  *
46  */
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/namei.h>
51 #include <sys/proc.h>
52 #include <sys/errno.h>
53 #include <sys/limits.h>
54 #include <sys/buf.h>
55 #include <sys/malloc.h>
56 #include <sys/ioctl.h>
57 #include <sys/disklabel.h>
58 #include <sys/device.h>
59 #include <sys/disk.h>
60 #include <sys/stat.h>
61 #include <sys/vnode.h>
62 #include <sys/fcntl.h>
63 #include <sys/uio.h>
64 #include <sys/conf.h>
65 #include <sys/dkio.h>
66 #include <sys/specdev.h>
67 
68 #include <crypto/blf.h>
69 
70 #include <dev/vndioctl.h>
71 
72 #ifdef VNDDEBUG
73 int vnddebug = 0x00;
74 #define	VDB_FOLLOW	0x01
75 #define	VDB_INIT	0x02
76 #define	VDB_IO		0x04
77 #define	DNPRINTF(f, p...)	do { if ((f) & vnddebug) printf(p); } while (0)
78 #else
79 #define	DNPRINTF(f, p...)	/* nothing */
80 #endif	/* VNDDEBUG */
81 
82 struct vnd_softc {
83 	struct device	 sc_dev;
84 	struct disk	 sc_dk;
85 
86 	char		 sc_file[VNDNLEN];	/* file we're covering */
87 	int		 sc_flags;		/* flags */
88 	size_t		 sc_size;		/* size of vnd in sectors */
89 	size_t		 sc_secsize;		/* sector size in bytes */
90 	size_t		 sc_nsectors;		/* # of sectors per track */
91 	size_t		 sc_ntracks;		/* # of tracks per cylinder */
92 	struct vnode	*sc_vp;			/* vnode */
93 	struct ucred	*sc_cred;		/* credentials */
94 	blf_ctx		*sc_keyctx;		/* key context */
95 };
96 
97 /* sc_flags */
98 #define	VNF_INITED	0x0001
99 #define	VNF_HAVELABEL	0x0002
100 #define	VNF_READONLY	0x0004
101 
102 #define	VNDRW(v)	((v)->sc_flags & VNF_READONLY ? FREAD : FREAD|FWRITE)
103 
104 struct vnd_softc *vnd_softc;
105 int numvnd = 0;
106 
107 /* called by main() at boot time */
108 void	vndattach(int);
109 
110 void	vndclear(struct vnd_softc *);
111 int	vndsetcred(struct proc *p, struct vnode *, struct vnd_ioctl *,
112 	    struct ucred **);
113 int	vndgetdisklabel(dev_t, struct vnd_softc *, struct disklabel *, int);
114 void	vndencrypt(struct vnd_softc *, caddr_t, size_t, daddr_t, int);
115 void	vndencryptbuf(struct vnd_softc *, struct buf *, int);
116 size_t	vndbdevsize(struct vnode *, struct proc *);
117 
118 void
119 vndencrypt(struct vnd_softc *sc, caddr_t addr, size_t size, daddr_t off,
120     int encrypt)
121 {
122 	int i, bsize;
123 	u_char iv[8];
124 
125 	bsize = dbtob(1);
126 	for (i = 0; i < size/bsize; i++) {
127 		memset(iv, 0, sizeof(iv));
128 		memcpy(iv, &off, sizeof(off));
129 		blf_ecb_encrypt(sc->sc_keyctx, iv, sizeof(iv));
130 		if (encrypt)
131 			blf_cbc_encrypt(sc->sc_keyctx, iv, addr, bsize);
132 		else
133 			blf_cbc_decrypt(sc->sc_keyctx, iv, addr, bsize);
134 
135 		addr += bsize;
136 		off++;
137 	}
138 }
139 
140 void
141 vndencryptbuf(struct vnd_softc *sc, struct buf *bp, int encrypt)
142 {
143 	vndencrypt(sc, bp->b_data, bp->b_bcount, bp->b_blkno, encrypt);
144 }
145 
146 void
147 vndattach(int num)
148 {
149 	char *mem;
150 	int i;
151 
152 	if (num <= 0)
153 		return;
154 	mem = mallocarray(num, sizeof(struct vnd_softc), M_DEVBUF,
155 	    M_NOWAIT | M_ZERO);
156 	if (mem == NULL) {
157 		printf("WARNING: no memory for vnode disks\n");
158 		return;
159 	}
160 	vnd_softc = (struct vnd_softc *)mem;
161 	for (i = 0; i < num; i++) {
162 		struct vnd_softc *sc = &vnd_softc[i];
163 
164 		sc->sc_dev.dv_unit = i;
165 		snprintf(sc->sc_dev.dv_xname, sizeof(sc->sc_dev.dv_xname),
166 		    "vnd%d", i);
167 		disk_construct(&sc->sc_dk);
168 		device_ref(&sc->sc_dev);
169 	}
170 	numvnd = num;
171 }
172 
173 int
174 vndopen(dev_t dev, int flags, int mode, struct proc *p)
175 {
176 	int unit = DISKUNIT(dev);
177 	struct vnd_softc *sc;
178 	int error = 0, part;
179 
180 	DNPRINTF(VDB_FOLLOW, "vndopen(%x, %x, %x, %p)\n", dev, flags, mode, p);
181 
182 	if (unit >= numvnd)
183 		return (ENXIO);
184 	sc = &vnd_softc[unit];
185 
186 	if ((error = disk_lock(&sc->sc_dk)) != 0)
187 		return (error);
188 
189 	if ((flags & FWRITE) && (sc->sc_flags & VNF_READONLY)) {
190 		error = EROFS;
191 		goto bad;
192 	}
193 
194 	if ((sc->sc_flags & VNF_INITED) &&
195 	    (sc->sc_flags & VNF_HAVELABEL) == 0 &&
196 	    sc->sc_dk.dk_openmask == 0) {
197 		sc->sc_flags |= VNF_HAVELABEL;
198 		vndgetdisklabel(dev, sc, sc->sc_dk.dk_label, 0);
199 	}
200 
201 	part = DISKPART(dev);
202 	error = disk_openpart(&sc->sc_dk, part, mode,
203 	    (sc->sc_flags & VNF_HAVELABEL) != 0);
204 
205 bad:
206 	disk_unlock(&sc->sc_dk);
207 	return (error);
208 }
209 
210 /*
211  * Load the label information on the named device
212  */
213 int
214 vndgetdisklabel(dev_t dev, struct vnd_softc *sc, struct disklabel *lp,
215     int spoofonly)
216 {
217 	memset(lp, 0, sizeof(struct disklabel));
218 
219 	lp->d_secsize = sc->sc_secsize;
220 	lp->d_nsectors = sc->sc_nsectors;
221 	lp->d_ntracks = sc->sc_ntracks;
222 	lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;
223 	if (lp->d_secpercyl)
224 		lp->d_ncylinders = sc->sc_size / lp->d_secpercyl;
225 
226 	strncpy(lp->d_typename, "vnd device", sizeof(lp->d_typename));
227 	lp->d_type = DTYPE_VND;
228 	strncpy(lp->d_packname, "fictitious", sizeof(lp->d_packname));
229 	DL_SETDSIZE(lp, sc->sc_size);
230 	lp->d_version = 1;
231 
232 	lp->d_magic = DISKMAGIC;
233 	lp->d_magic2 = DISKMAGIC;
234 	lp->d_checksum = dkcksum(lp);
235 
236 	/* Call the generic disklabel extraction routine */
237 	return readdisklabel(DISKLABELDEV(dev), vndstrategy, lp, spoofonly);
238 }
239 
240 int
241 vndclose(dev_t dev, int flags, int mode, struct proc *p)
242 {
243 	int unit = DISKUNIT(dev);
244 	struct vnd_softc *sc;
245 	int part;
246 
247 	DNPRINTF(VDB_FOLLOW, "vndclose(%x, %x, %x, %p)\n", dev, flags, mode, p);
248 
249 	if (unit >= numvnd)
250 		return (ENXIO);
251 	sc = &vnd_softc[unit];
252 
253 	disk_lock_nointr(&sc->sc_dk);
254 
255 	part = DISKPART(dev);
256 
257 	disk_closepart(&sc->sc_dk, part, mode);
258 
259 #if 0
260 	if (sc->sc_dk.dk_openmask == 0)
261 		sc->sc_flags &= ~VNF_HAVELABEL;
262 #endif
263 
264 	disk_unlock(&sc->sc_dk);
265 	return (0);
266 }
267 
268 void
269 vndstrategy(struct buf *bp)
270 {
271 	int unit = DISKUNIT(bp->b_dev);
272 	struct vnd_softc *sc;
273 	struct partition *p;
274 	off_t off;
275 	long origbcount;
276 	int s;
277 
278 	DNPRINTF(VDB_FOLLOW, "vndstrategy(%p): unit %d\n", bp, unit);
279 
280 	if (unit >= numvnd) {
281 		bp->b_error = ENXIO;
282 		goto bad;
283 	}
284 	sc = &vnd_softc[unit];
285 
286 	if ((sc->sc_flags & VNF_HAVELABEL) == 0) {
287 		bp->b_error = ENXIO;
288 		goto bad;
289 	}
290 
291 	/*
292 	 * Many of the distrib scripts assume they can issue arbitrary
293 	 * sized requests to raw vnd devices irrespective of the
294 	 * emulated disk geometry.
295 	 *
296 	 * To continue supporting this, round the block count up to a
297 	 * multiple of d_secsize for bounds_check_with_label(), and
298 	 * then restore afterwards.
299 	 *
300 	 * We only do this for non-encrypted vnd, because encryption
301 	 * requires operating on blocks at a time.
302 	 */
303 	origbcount = bp->b_bcount;
304 	if (sc->sc_keyctx == NULL) {
305 		u_int32_t secsize = sc->sc_dk.dk_label->d_secsize;
306 		bp->b_bcount = ((origbcount + secsize - 1) & ~(secsize - 1));
307 #ifdef DIAGNOSTIC
308 		if (bp->b_bcount != origbcount) {
309 			struct process *curpr = curproc->p_p;
310 			printf("%s: sloppy %s from proc %d (%s): "
311 			    "blkno %lld bcount %ld\n", sc->sc_dev.dv_xname,
312 			    (bp->b_flags & B_READ) ? "read" : "write",
313 			    curpr->ps_pid, curpr->ps_comm,
314 			    (long long)bp->b_blkno, origbcount);
315 		}
316 #endif
317 	}
318 
319 	if (bounds_check_with_label(bp, sc->sc_dk.dk_label) == -1) {
320 		bp->b_resid = bp->b_bcount = origbcount;
321 		goto done;
322 	}
323 
324 	if (origbcount < bp->b_bcount)
325 		bp->b_bcount = origbcount;
326 
327 	p = &sc->sc_dk.dk_label->d_partitions[DISKPART(bp->b_dev)];
328 	off = DL_GETPOFFSET(p) * sc->sc_dk.dk_label->d_secsize +
329 	    (u_int64_t)bp->b_blkno * DEV_BSIZE;
330 
331 	if (sc->sc_keyctx && !(bp->b_flags & B_READ))
332 		vndencryptbuf(sc, bp, 1);
333 
334 	/*
335 	 * Use IO_NOLIMIT because upper layer has already checked I/O
336 	 * for limits, so there is no need to do it again.
337 	 *
338 	 * We use IO_NOCACHE because this data should be cached at the
339 	 * upper layer, so there is no need to cache it again.
340 	 */
341 	bp->b_error = vn_rdwr((bp->b_flags & B_READ) ? UIO_READ : UIO_WRITE,
342 	    sc->sc_vp, bp->b_data, bp->b_bcount, off, UIO_SYSSPACE,
343 	    IO_NOCACHE | IO_SYNC | IO_NOLIMIT, sc->sc_cred, &bp->b_resid, curproc);
344 	if (bp->b_error)
345 		bp->b_flags |= B_ERROR;
346 
347 	/* Data in buffer cache needs to be in clear */
348 	if (sc->sc_keyctx)
349 		vndencryptbuf(sc, bp, 0);
350 
351 	goto done;
352 
353  bad:
354 	bp->b_flags |= B_ERROR;
355 	bp->b_resid = bp->b_bcount;
356  done:
357 	s = splbio();
358 	biodone(bp);
359 	splx(s);
360 }
361 
362 /* ARGSUSED */
363 int
364 vndread(dev_t dev, struct uio *uio, int flags)
365 {
366 	return (physio(vndstrategy, dev, B_READ, minphys, uio));
367 }
368 
369 /* ARGSUSED */
370 int
371 vndwrite(dev_t dev, struct uio *uio, int flags)
372 {
373 	return (physio(vndstrategy, dev, B_WRITE, minphys, uio));
374 }
375 
376 size_t
377 vndbdevsize(struct vnode *vp, struct proc *p)
378 {
379 	struct partinfo pi;
380 	struct bdevsw *bsw;
381 	dev_t dev;
382 
383 	dev = vp->v_rdev;
384 	bsw = bdevsw_lookup(dev);
385 	if (bsw->d_ioctl == NULL)
386 		return (0);
387 	if (bsw->d_ioctl(dev, DIOCGPART, (caddr_t)&pi, FREAD, p))
388 		return (0);
389 	DNPRINTF(VDB_INIT, "vndbdevsize: size %llu secsize %u\n",
390 	    DL_GETPSIZE(pi.part), pi.disklab->d_secsize);
391 	return (DL_GETPSIZE(pi.part));
392 }
393 
394 /* ARGSUSED */
395 int
396 vndioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
397 {
398 	int unit = DISKUNIT(dev);
399 	struct disklabel *lp;
400 	struct vnd_softc *sc;
401 	struct vnd_ioctl *vio;
402 	struct vnd_user *vnu;
403 	struct vattr vattr;
404 	int error, part, pmask;
405 
406 	DNPRINTF(VDB_FOLLOW, "vndioctl(%x, %lx, %p, %x, %p): unit %d\n",
407 	    dev, cmd, addr, flag, p, unit);
408 
409 	error = suser(p);
410 	if (error)
411 		return (error);
412 	if (unit >= numvnd)
413 		return (ENXIO);
414 
415 	sc = &vnd_softc[unit];
416 	vio = (struct vnd_ioctl *)addr;
417 	switch (cmd) {
418 
419 	case VNDIOCSET:
420 	    {
421 		char name[VNDNLEN], key[BLF_MAXUTILIZED];
422 		struct nameidata nd;
423 		struct ucred *cred = NULL;
424 		size_t size;
425 		int vplocked;
426 		int rw;
427 
428 		if (sc->sc_flags & VNF_INITED)
429 			return (EBUSY);
430 
431 		/* Geometry eventually has to fit into label fields */
432 		if (vio->vnd_secsize > UINT_MAX ||
433 		    vio->vnd_secsize == 0 ||
434 		    vio->vnd_ntracks > UINT_MAX ||
435 		    vio->vnd_nsectors > UINT_MAX)
436 			return (EINVAL);
437 
438 		if ((error = copyinstr(vio->vnd_file, name,
439 		    sizeof(name), NULL)))
440 			return (error);
441 
442 		if (vio->vnd_keylen > 0) {
443 			if (vio->vnd_keylen > sizeof(key))
444 				vio->vnd_keylen = sizeof(key);
445 
446 			if ((error = copyin(vio->vnd_key, key,
447 			    vio->vnd_keylen)) != 0)
448 				return (error);
449 		}
450 
451 		/*
452 		 * Open for read and write first. This lets vn_open() weed out
453 		 * directories, sockets, etc. so we don't have to worry about
454 		 * them.
455 		 */
456 		NDINIT(&nd, 0, 0, UIO_SYSSPACE, name, p);
457 		nd.ni_unveil = UNVEIL_READ | UNVEIL_WRITE;
458 		rw = FREAD|FWRITE;
459 		error = vn_open(&nd, FREAD|FWRITE, 0);
460 		if (error == EROFS) {
461 			NDINIT(&nd, 0, 0, UIO_SYSSPACE, name, p);
462 			nd.ni_unveil = UNVEIL_READ | UNVEIL_WRITE;
463 			rw = FREAD;
464 			error = vn_open(&nd, FREAD, 0);
465 		}
466 		if (error)
467 			return (error);
468 		vplocked = 1;
469 
470 		error = VOP_GETATTR(nd.ni_vp, &vattr, p->p_ucred, p);
471 		if (error) {
472 fail:
473 			if (vplocked)
474 				VOP_UNLOCK(nd.ni_vp);
475 			vn_close(nd.ni_vp, rw, p->p_ucred, p);
476 			if (cred != NULL)
477 				crfree(cred);
478 			return (error);
479 		}
480 
481 		/* Cannot put a vnd on top of a vnd */
482 		if (major(vattr.va_fsid) == major(dev)) {
483 			error = EINVAL;
484 			goto fail;
485 		}
486 
487 		if ((error = vndsetcred(p, nd.ni_vp, vio, &cred)) != 0)
488 			goto fail;
489 
490 		VOP_UNLOCK(nd.ni_vp);
491 		vplocked = 0;
492 
493 		if (nd.ni_vp->v_type == VBLK) {
494 			size = vndbdevsize(nd.ni_vp, p);
495 			/* XXX is size 0 ok? */
496 		} else
497 			size = vattr.va_size / vio->vnd_secsize;
498 
499 		if ((error = disk_lock(&sc->sc_dk)) != 0)
500 			goto fail;
501 		if (sc->sc_flags & VNF_INITED) {
502 			disk_unlock(&sc->sc_dk);
503 			error = EBUSY;
504 			goto fail;
505 		}
506 
507 		/* Set geometry for device. */
508 		sc->sc_secsize = vio->vnd_secsize;
509 		sc->sc_ntracks = vio->vnd_ntracks;
510 		sc->sc_nsectors = vio->vnd_nsectors;
511 		sc->sc_size = size;
512 
513 		if (rw == FREAD)
514 			sc->sc_flags |= VNF_READONLY;
515 		else
516 			sc->sc_flags &= ~VNF_READONLY;
517 
518 		memcpy(sc->sc_file, name, sizeof(sc->sc_file));
519 
520 		if (vio->vnd_keylen > 0) {
521 			sc->sc_keyctx = malloc(sizeof(*sc->sc_keyctx), M_DEVBUF,
522 			    M_WAITOK);
523 			blf_key(sc->sc_keyctx, key, vio->vnd_keylen);
524 			explicit_bzero(key, vio->vnd_keylen);
525 		} else
526 			sc->sc_keyctx = NULL;
527 
528 		sc->sc_vp = nd.ni_vp;
529 		sc->sc_cred = cred;
530 		vio->vnd_size = sc->sc_size * sc->sc_secsize;
531 		sc->sc_flags |= VNF_INITED;
532 
533 		DNPRINTF(VDB_INIT, "vndioctl: SET vp %p size %llx\n",
534 		    sc->sc_vp, (unsigned long long)sc->sc_size);
535 
536 		/* Attach the disk. */
537 		sc->sc_dk.dk_name = sc->sc_dev.dv_xname;
538 		disk_attach(&sc->sc_dev, &sc->sc_dk);
539 
540 		disk_unlock(&sc->sc_dk);
541 
542 		break;
543 	    }
544 	case VNDIOCCLR:
545 		if ((error = disk_lock(&sc->sc_dk)) != 0)
546 			return (error);
547 		if ((sc->sc_flags & VNF_INITED) == 0) {
548 			disk_unlock(&sc->sc_dk);
549 			return (ENXIO);
550 		}
551 
552 		/*
553 		 * Don't unconfigure if any other partitions are open
554 		 * or if both the character and block flavors of this
555 		 * partition are open.
556 		 */
557 		part = DISKPART(dev);
558 		pmask = (1 << part);
559 		if ((sc->sc_dk.dk_openmask & ~pmask) ||
560 		    ((sc->sc_dk.dk_bopenmask & pmask) &&
561 		    (sc->sc_dk.dk_copenmask & pmask))) {
562 			disk_unlock(&sc->sc_dk);
563 			return (EBUSY);
564 		}
565 
566 		vndclear(sc);
567 		DNPRINTF(VDB_INIT, "vndioctl: CLRed\n");
568 
569 		/* Free crypto key */
570 		if (sc->sc_keyctx) {
571 			explicit_bzero(sc->sc_keyctx, sizeof(*sc->sc_keyctx));
572 			free(sc->sc_keyctx, M_DEVBUF, sizeof(*sc->sc_keyctx));
573 		}
574 
575 		/* Detach the disk. */
576 		disk_detach(&sc->sc_dk);
577 		disk_unlock(&sc->sc_dk);
578 		break;
579 
580 	case VNDIOCGET:
581 		vnu = (struct vnd_user *)addr;
582 
583 		if (vnu->vnu_unit == -1)
584 			vnu->vnu_unit = unit;
585 		if (vnu->vnu_unit >= numvnd)
586 			return (ENXIO);
587 		if (vnu->vnu_unit < 0)
588 			return (EINVAL);
589 
590 		sc = &vnd_softc[vnu->vnu_unit];
591 
592 		if (sc->sc_flags & VNF_INITED) {
593 			error = VOP_GETATTR(sc->sc_vp, &vattr, p->p_ucred, p);
594 			if (error)
595 				return (error);
596 
597 			strlcpy(vnu->vnu_file, sc->sc_file,
598 			    sizeof(vnu->vnu_file));
599 			vnu->vnu_dev = vattr.va_fsid;
600 			vnu->vnu_ino = vattr.va_fileid;
601 		} else {
602 			vnu->vnu_dev = 0;
603 			vnu->vnu_ino = 0;
604 		}
605 
606 		break;
607 
608 	case DIOCRLDINFO:
609 		if ((sc->sc_flags & VNF_HAVELABEL) == 0)
610 			return (ENOTTY);
611 		lp = malloc(sizeof(*lp), M_TEMP, M_WAITOK);
612 		vndgetdisklabel(dev, sc, lp, 0);
613 		*(sc->sc_dk.dk_label) = *lp;
614 		free(lp, M_TEMP, sizeof(*lp));
615 		return (0);
616 
617 	case DIOCGPDINFO:
618 		if ((sc->sc_flags & VNF_HAVELABEL) == 0)
619 			return (ENOTTY);
620 		vndgetdisklabel(dev, sc, (struct disklabel *)addr, 1);
621 		return (0);
622 
623 	case DIOCGDINFO:
624 		if ((sc->sc_flags & VNF_HAVELABEL) == 0)
625 			return (ENOTTY);
626 		*(struct disklabel *)addr = *(sc->sc_dk.dk_label);
627 		return (0);
628 
629 	case DIOCGPART:
630 		if ((sc->sc_flags & VNF_HAVELABEL) == 0)
631 			return (ENOTTY);
632 		((struct partinfo *)addr)->disklab = sc->sc_dk.dk_label;
633 		((struct partinfo *)addr)->part =
634 		    &sc->sc_dk.dk_label->d_partitions[DISKPART(dev)];
635 		return (0);
636 
637 	case DIOCWDINFO:
638 	case DIOCSDINFO:
639 		if ((sc->sc_flags & VNF_HAVELABEL) == 0)
640 			return (ENOTTY);
641 		if ((flag & FWRITE) == 0)
642 			return (EBADF);
643 
644 		if ((error = disk_lock(&sc->sc_dk)) != 0)
645 			return (error);
646 
647 		error = setdisklabel(sc->sc_dk.dk_label,
648 		    (struct disklabel *)addr, /* sc->sc_dk.dk_openmask */ 0);
649 		if (error == 0) {
650 			if (cmd == DIOCWDINFO)
651 				error = writedisklabel(DISKLABELDEV(dev),
652 				    vndstrategy, sc->sc_dk.dk_label);
653 		}
654 
655 		disk_unlock(&sc->sc_dk);
656 		return (error);
657 
658 	default:
659 		return (ENOTTY);
660 	}
661 
662 	return (0);
663 }
664 
665 /*
666  * Duplicate the current processes' credentials.  Since we are called only
667  * as the result of a SET ioctl and only root can do that, any future access
668  * to this "disk" is essentially as root.  Note that credentials may change
669  * if some other uid can write directly to the mapped file (NFS).
670  */
671 int
672 vndsetcred(struct proc *p, struct vnode *vp, struct vnd_ioctl *vio,
673     struct ucred **newcredp)
674 {
675 	void *buf;
676 	size_t size;
677 	struct ucred *new;
678 	int error;
679 
680 	new = crdup(p->p_ucred);
681 	buf = malloc(DEV_BSIZE, M_TEMP, M_WAITOK);
682 	size = DEV_BSIZE;
683 
684 	/* XXX: Horrible kludge to establish credentials for NFS */
685 	error = vn_rdwr(UIO_READ, vp, buf, size, 0, UIO_SYSSPACE, 0,
686 	    new, NULL, curproc);
687 
688 	free(buf, M_TEMP, DEV_BSIZE);
689 	if (error == 0)
690 		*newcredp = new;
691 	else
692 		crfree(new);
693 	return (error);
694 }
695 
696 void
697 vndclear(struct vnd_softc *sc)
698 {
699 	struct vnode *vp = sc->sc_vp;
700 	struct proc *p = curproc;		/* XXX */
701 
702 	DNPRINTF(VDB_FOLLOW, "vndclear(%p): vp %p\n", sc, vp);
703 
704 	if (vp == NULL)
705 		panic("vndioctl: null vp");
706 	(void) vn_close(vp, VNDRW(sc), sc->sc_cred, p);
707 	crfree(sc->sc_cred);
708 	sc->sc_flags = 0;
709 	sc->sc_vp = NULL;
710 	sc->sc_cred = NULL;
711 	sc->sc_size = 0;
712 	memset(sc->sc_file, 0, sizeof(sc->sc_file));
713 }
714 
715 daddr_t
716 vndsize(dev_t dev)
717 {
718 	/* We don't support swapping to vnd anymore. */
719 	return (-1);
720 }
721 
722 int
723 vnddump(dev_t dev, daddr_t blkno, caddr_t va, size_t size)
724 {
725 	/* Not implemented. */
726 	return (ENXIO);
727 }
728