1/*-
2 * Copyright (c) 2002 Poul-Henning Kamp
3 * Copyright (c) 2002 Networks Associates Technology, Inc.
4 * All rights reserved.
5 *
6 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
7 * and NAI Labs, the Security Research Division of Network Associates, Inc.
8 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
9 * DARPA CHATS research program.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: releng/11.0/sys/geom/geom_mbr.c 300288 2016-05-20 08:25:37Z kib $");
35
36#include <sys/param.h>
37#include <sys/errno.h>
38#include <sys/endian.h>
39#include <sys/systm.h>
40#include <sys/sysctl.h>
41#include <sys/kernel.h>
42#include <sys/fcntl.h>
43#include <sys/malloc.h>
44#include <sys/bio.h>
45#include <sys/lock.h>
46#include <sys/mutex.h>
47#include <sys/md5.h>
48#include <sys/proc.h>
49
50#include <sys/diskmbr.h>
51#include <sys/sbuf.h>
52#include <geom/geom.h>
53#include <geom/geom_slice.h>
54
55FEATURE(geom_mbr, "GEOM DOS/MBR partitioning support");
56
57#define MBR_CLASS_NAME "MBR"
58#define MBREXT_CLASS_NAME "MBREXT"
59
60static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
61        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
62        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
63        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
64        { 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
65};
66
67static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
68        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
69        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
70        { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
71        { 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, },
72};
73
74static void
75g_mbr_print(int i, struct dos_partition *dp)
76{
77
78	printf("[%d] f:%02x typ:%d", i, dp->dp_flag, dp->dp_typ);
79	printf(" s(CHS):%d/%d/%d", DPCYL(dp->dp_scyl, dp->dp_ssect),
80	    dp->dp_shd, DPSECT(dp->dp_ssect));
81	printf(" e(CHS):%d/%d/%d", DPCYL(dp->dp_ecyl, dp->dp_esect),
82	    dp->dp_ehd, DPSECT(dp->dp_esect));
83	printf(" s:%d l:%d\n", dp->dp_start, dp->dp_size);
84}
85
86struct g_mbr_softc {
87	int		type [NDOSPART];
88	u_int		sectorsize;
89	u_char		sec0[512];
90	u_char		slicesum[16];
91};
92
93/*
94 * XXX: Add gctl_req arg and give good error msgs.
95 * XXX: Check that length argument does not bring boot code inside any slice.
96 */
97static int
98g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, u_char *sec0, int len __unused)
99{
100	int i, error;
101	off_t l[NDOSPART];
102	struct dos_partition ndp[NDOSPART], *dp;
103	MD5_CTX md5sum;
104
105	g_topology_assert();
106
107	if (sec0[0x1fe] != 0x55 && sec0[0x1ff] != 0xaa)
108		return (EBUSY);
109
110	dp = ndp;
111	for (i = 0; i < NDOSPART; i++) {
112		dos_partition_dec(
113		    sec0 + DOSPARTOFF + i * sizeof(struct dos_partition),
114		    dp + i);
115	}
116	if ((!bcmp(dp, historical_bogus_partition_table,
117	    sizeof historical_bogus_partition_table)) ||
118	    (!bcmp(dp, historical_bogus_partition_table_fixed,
119	    sizeof historical_bogus_partition_table_fixed))) {
120		/*
121		 * We will not allow people to write these from "the inside",
122		 * Since properly selfdestructing takes too much code.  If
123		 * people really want to do this, they cannot have any
124		 * providers of this geom open, and in that case they can just
125		 * as easily overwrite the MBR in the parent device.
126		 */
127		return(EBUSY);
128	}
129	for (i = 0; i < NDOSPART; i++) {
130		/*
131		 * A Protective MBR (PMBR) has a single partition of
132		 * type 0xEE spanning the whole disk. Such a MBR
133		 * protects a GPT on the disk from MBR tools that
134		 * don't know anything about GPT. We're interpreting
135		 * it a bit more loosely: any partition of type 0xEE
136		 * is to be skipped as it doesn't contain any data
137		 * that we should care about. We still allow other
138		 * partitions to be present in the MBR. A PMBR will
139		 * be handled correctly anyway.
140		 */
141		if (dp[i].dp_typ == DOSPTYP_PMBR)
142			l[i] = 0;
143		else if (dp[i].dp_flag != 0 && dp[i].dp_flag != 0x80)
144			l[i] = 0;
145		else if (dp[i].dp_typ == 0)
146			l[i] = 0;
147		else
148			l[i] = (off_t)dp[i].dp_size * ms->sectorsize;
149		error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
150		    (off_t)dp[i].dp_start * ms->sectorsize, l[i],
151		    ms->sectorsize, "%ss%d", gp->name, 1 + i);
152		if (error)
153			return (error);
154	}
155	for (i = 0; i < NDOSPART; i++) {
156		ms->type[i] = dp[i].dp_typ;
157		g_slice_config(gp, i, G_SLICE_CONFIG_SET,
158		    (off_t)dp[i].dp_start * ms->sectorsize, l[i],
159		    ms->sectorsize, "%ss%d", gp->name, 1 + i);
160	}
161	bcopy(sec0, ms->sec0, 512);
162
163	/*
164	 * Calculate MD5 from the first sector and use it for avoiding
165	 * recursive slices creation.
166	 */
167	MD5Init(&md5sum);
168	MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0));
169	MD5Final(ms->slicesum, &md5sum);
170
171	return (0);
172}
173
174static int
175g_mbr_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td)
176{
177	struct g_geom *gp;
178	struct g_mbr_softc *ms;
179	struct g_slicer *gsp;
180	struct g_consumer *cp;
181	int error, opened;
182
183	gp = pp->geom;
184	gsp = gp->softc;
185	ms = gsp->softc;
186
187	opened = 0;
188	error = 0;
189	switch(cmd) {
190	case DIOCSMBR: {
191		if (!(fflag & FWRITE))
192			return (EPERM);
193		g_topology_lock();
194		cp = LIST_FIRST(&gp->consumer);
195		if (cp->acw == 0) {
196			error = g_access(cp, 0, 1, 0);
197			if (error == 0)
198				opened = 1;
199		}
200		if (!error)
201			error = g_mbr_modify(gp, ms, data, 512);
202		if (!error)
203			error = g_write_data(cp, 0, data, 512);
204		if (opened)
205			g_access(cp, 0, -1 , 0);
206		g_topology_unlock();
207		return(error);
208	}
209	default:
210		return (ENOIOCTL);
211	}
212}
213
214static int
215g_mbr_start(struct bio *bp)
216{
217	struct g_provider *pp;
218	struct g_geom *gp;
219	struct g_mbr_softc *mp;
220	struct g_slicer *gsp;
221	int idx;
222
223	pp = bp->bio_to;
224	idx = pp->index;
225	gp = pp->geom;
226	gsp = gp->softc;
227	mp = gsp->softc;
228	if (bp->bio_cmd == BIO_GETATTR) {
229		if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
230			return (1);
231		if (g_handleattr_off_t(bp, "MBR::offset",
232		    gsp->slices[idx].offset))
233			return (1);
234		if (g_handleattr(bp, "MBR::slicesum", mp->slicesum,
235		    sizeof(mp->slicesum)))
236			return (1);
237	}
238
239	return (0);
240}
241
242static void
243g_mbr_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
244{
245	struct g_mbr_softc *mp;
246	struct g_slicer *gsp;
247
248	gsp = gp->softc;
249	mp = gsp->softc;
250	g_slice_dumpconf(sb, indent, gp, cp, pp);
251	if (pp != NULL) {
252		if (indent == NULL)
253			sbuf_printf(sb, " ty %d", mp->type[pp->index]);
254		else
255			sbuf_printf(sb, "%s<type>%d</type>\n", indent,
256			    mp->type[pp->index]);
257	}
258}
259
260static struct g_geom *
261g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist)
262{
263	struct g_geom *gp;
264	struct g_consumer *cp;
265	int error;
266	struct g_mbr_softc *ms;
267	u_int fwsectors, sectorsize;
268	u_char *buf;
269	u_char hash[16];
270	MD5_CTX md5sum;
271
272	g_trace(G_T_TOPOLOGY, "mbr_taste(%s,%s)", mp->name, pp->name);
273	g_topology_assert();
274	if (!strcmp(pp->geom->class->name, MBR_CLASS_NAME))
275		return (NULL);
276	gp = g_slice_new(mp, NDOSPART, pp, &cp, &ms, sizeof *ms, g_mbr_start);
277	if (gp == NULL)
278		return (NULL);
279	g_topology_unlock();
280	do {
281		error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
282		if (error)
283			fwsectors = 17;
284		sectorsize = cp->provider->sectorsize;
285		if (sectorsize < 512)
286			break;
287		ms->sectorsize = sectorsize;
288		buf = g_read_data(cp, 0, sectorsize, NULL);
289		if (buf == NULL)
290			break;
291
292		/*
293		 * Calculate MD5 from the first sector and use it for avoiding
294		 * recursive slices creation.
295		 */
296		bcopy(buf, ms->sec0, 512);
297		MD5Init(&md5sum);
298		MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0));
299		MD5Final(ms->slicesum, &md5sum);
300
301		error = g_getattr("MBR::slicesum", cp, &hash);
302		if (!error && !bcmp(ms->slicesum, hash, sizeof(hash))) {
303			g_free(buf);
304			break;
305		}
306
307		g_topology_lock();
308		g_mbr_modify(gp, ms, buf, 512);
309		g_topology_unlock();
310		g_free(buf);
311		break;
312	} while (0);
313	g_topology_lock();
314	g_access(cp, -1, 0, 0);
315	if (LIST_EMPTY(&gp->provider)) {
316		g_slice_spoiled(cp);
317		return (NULL);
318	}
319	return (gp);
320}
321
322static void
323g_mbr_config(struct gctl_req *req, struct g_class *mp, const char *verb)
324{
325	struct g_geom *gp;
326	struct g_consumer *cp;
327	struct g_mbr_softc *ms;
328	struct g_slicer *gsp;
329	int opened = 0, error = 0;
330	void *data;
331	int len;
332
333	g_topology_assert();
334	gp = gctl_get_geom(req, mp, "geom");
335	if (gp == NULL)
336		return;
337	if (strcmp(verb, "write MBR")) {
338		gctl_error(req, "Unknown verb");
339		return;
340	}
341	gsp = gp->softc;
342	ms = gsp->softc;
343	data = gctl_get_param(req, "data", &len);
344	if (data == NULL)
345		return;
346	if (len < 512 || (len % 512)) {
347		gctl_error(req, "Wrong request length");
348		return;
349	}
350	cp = LIST_FIRST(&gp->consumer);
351	if (cp->acw == 0) {
352		error = g_access(cp, 0, 1, 0);
353		if (error == 0)
354			opened = 1;
355	}
356	if (!error)
357		error = g_mbr_modify(gp, ms, data, len);
358	if (error)
359		gctl_error(req, "conflict with open slices");
360	if (!error)
361		error = g_write_data(cp, 0, data, len);
362	if (error)
363		gctl_error(req, "sector zero write failed");
364	if (opened)
365		g_access(cp, 0, -1 , 0);
366	return;
367}
368
369static struct g_class g_mbr_class	= {
370	.name = MBR_CLASS_NAME,
371	.version = G_VERSION,
372	.taste = g_mbr_taste,
373	.dumpconf = g_mbr_dumpconf,
374	.ctlreq = g_mbr_config,
375	.ioctl = g_mbr_ioctl,
376};
377
378DECLARE_GEOM_CLASS(g_mbr_class, g_mbr);
379
380#define NDOSEXTPART		32
381struct g_mbrext_softc {
382	int		type [NDOSEXTPART];
383};
384
385static int
386g_mbrext_start(struct bio *bp)
387{
388	struct g_provider *pp;
389	struct g_geom *gp;
390	struct g_mbrext_softc *mp;
391	struct g_slicer *gsp;
392	int idx;
393
394	pp = bp->bio_to;
395	idx = pp->index;
396	gp = pp->geom;
397	gsp = gp->softc;
398	mp = gsp->softc;
399	if (bp->bio_cmd == BIO_GETATTR) {
400		if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
401			return (1);
402	}
403	return (0);
404}
405
406static void
407g_mbrext_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
408{
409	struct g_mbrext_softc *mp;
410	struct g_slicer *gsp;
411
412	g_slice_dumpconf(sb, indent, gp, cp, pp);
413	gsp = gp->softc;
414	mp = gsp->softc;
415	if (pp != NULL) {
416		if (indent == NULL)
417			sbuf_printf(sb, " ty %d", mp->type[pp->index]);
418		else
419			sbuf_printf(sb, "%s<type>%d</type>\n", indent,
420			    mp->type[pp->index]);
421	}
422}
423
424static struct g_geom *
425g_mbrext_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
426{
427	struct g_geom *gp;
428	struct g_consumer *cp;
429	int error, i, slice;
430	struct g_mbrext_softc *ms;
431	off_t off;
432	u_char *buf;
433	struct dos_partition dp[4];
434	u_int fwsectors, sectorsize;
435
436	g_trace(G_T_TOPOLOGY, "g_mbrext_taste(%s,%s)", mp->name, pp->name);
437	g_topology_assert();
438	if (strcmp(pp->geom->class->name, MBR_CLASS_NAME))
439		return (NULL);
440	gp = g_slice_new(mp, NDOSEXTPART, pp, &cp, &ms, sizeof *ms,
441	    g_mbrext_start);
442	if (gp == NULL)
443		return (NULL);
444	g_topology_unlock();
445	off = 0;
446	slice = 0;
447	do {
448		error = g_getattr("MBR::type", cp, &i);
449		if (error || (i != DOSPTYP_EXT && i != DOSPTYP_EXTLBA))
450			break;
451		error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
452		if (error)
453			fwsectors = 17;
454		sectorsize = cp->provider->sectorsize;
455		if (sectorsize != 512)
456			break;
457		for (;;) {
458			buf = g_read_data(cp, off, sectorsize, NULL);
459			if (buf == NULL)
460				break;
461			if (buf[0x1fe] != 0x55 && buf[0x1ff] != 0xaa) {
462				g_free(buf);
463				break;
464			}
465			for (i = 0; i < NDOSPART; i++)
466				dos_partition_dec(
467				    buf + DOSPARTOFF +
468				    i * sizeof(struct dos_partition), dp + i);
469			g_free(buf);
470			if (0 && bootverbose) {
471				printf("MBREXT Slice %d on %s:\n",
472				    slice + 5, gp->name);
473				g_mbr_print(0, dp);
474				g_mbr_print(1, dp + 1);
475			}
476			if ((dp[0].dp_flag & 0x7f) == 0 &&
477			     dp[0].dp_size != 0 && dp[0].dp_typ != 0) {
478				g_topology_lock();
479				g_slice_config(gp, slice, G_SLICE_CONFIG_SET,
480				    (((off_t)dp[0].dp_start) << 9ULL) + off,
481				    ((off_t)dp[0].dp_size) << 9ULL,
482				    sectorsize,
483				    "%*.*s%d",
484				    (int)strlen(gp->name) - 1,
485				    (int)strlen(gp->name) - 1,
486				    gp->name,
487				    slice + 5);
488				g_topology_unlock();
489				ms->type[slice] = dp[0].dp_typ;
490				slice++;
491			}
492			if (dp[1].dp_flag != 0)
493				break;
494			if (dp[1].dp_typ != DOSPTYP_EXT &&
495			    dp[1].dp_typ != DOSPTYP_EXTLBA)
496				break;
497			if (dp[1].dp_size == 0)
498				break;
499			off = ((off_t)dp[1].dp_start) << 9ULL;
500		}
501		break;
502	} while (0);
503	g_topology_lock();
504	g_access(cp, -1, 0, 0);
505	if (LIST_EMPTY(&gp->provider)) {
506		g_slice_spoiled(cp);
507		return (NULL);
508	}
509	return (gp);
510}
511
512
513static struct g_class g_mbrext_class	= {
514	.name = MBREXT_CLASS_NAME,
515	.version = G_VERSION,
516	.taste = g_mbrext_taste,
517	.dumpconf = g_mbrext_dumpconf,
518};
519
520DECLARE_GEOM_CLASS(g_mbrext_class, g_mbrext);
521