FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_mbr.c
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2002 Poul-Henning Kamp
5 * Copyright (c) 2002 Networks Associates Technology, Inc.
6 * All rights reserved.
7 *
8 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
9 * and NAI Labs, the Security Research Division of Network Associates, Inc.
10 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
11 * DARPA CHATS research program.
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 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD: releng/12.0/sys/geom/geom_mbr.c 332387 2018-04-10 19:18:16Z kevans $");
37
38 #include <sys/param.h>
39 #include <sys/errno.h>
40 #include <sys/endian.h>
41 #include <sys/systm.h>
42 #include <sys/sysctl.h>
43 #include <sys/kernel.h>
44 #include <sys/fcntl.h>
45 #include <sys/malloc.h>
46 #include <sys/bio.h>
47 #include <sys/lock.h>
48 #include <sys/mutex.h>
49 #include <sys/md5.h>
50 #include <sys/proc.h>
51
52 #include <sys/diskmbr.h>
53 #include <sys/sbuf.h>
54 #include <geom/geom.h>
55 #include <geom/geom_slice.h>
56
57 FEATURE(geom_mbr, "GEOM DOS/MBR partitioning support");
58
59 #define MBR_CLASS_NAME "MBR"
60 #define MBREXT_CLASS_NAME "MBREXT"
61
62 static int g_mbr_once = 0;
63
64 static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
65 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
66 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
67 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
68 { 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
69 };
70
71 static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
72 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
73 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
74 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
75 { 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, },
76 };
77
78 static void
79 g_mbr_print(int i, struct dos_partition *dp)
80 {
81
82 printf("[%d] f:%02x typ:%d", i, dp->dp_flag, dp->dp_typ);
83 printf(" s(CHS):%d/%d/%d", DPCYL(dp->dp_scyl, dp->dp_ssect),
84 dp->dp_shd, DPSECT(dp->dp_ssect));
85 printf(" e(CHS):%d/%d/%d", DPCYL(dp->dp_ecyl, dp->dp_esect),
86 dp->dp_ehd, DPSECT(dp->dp_esect));
87 printf(" s:%d l:%d\n", dp->dp_start, dp->dp_size);
88 }
89
90 struct g_mbr_softc {
91 int type [NDOSPART];
92 u_int sectorsize;
93 u_char sec0[512];
94 u_char slicesum[16];
95 };
96
97 /*
98 * XXX: Add gctl_req arg and give good error msgs.
99 * XXX: Check that length argument does not bring boot code inside any slice.
100 */
101 static int
102 g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, u_char *sec0, int len __unused)
103 {
104 int i, error;
105 off_t l[NDOSPART];
106 struct dos_partition ndp[NDOSPART], *dp;
107 MD5_CTX md5sum;
108
109 g_topology_assert();
110
111 if (sec0[0x1fe] != 0x55 && sec0[0x1ff] != 0xaa)
112 return (EBUSY);
113
114 dp = ndp;
115 for (i = 0; i < NDOSPART; i++) {
116 dos_partition_dec(
117 sec0 + DOSPARTOFF + i * sizeof(struct dos_partition),
118 dp + i);
119 }
120 if ((!bcmp(dp, historical_bogus_partition_table,
121 sizeof historical_bogus_partition_table)) ||
122 (!bcmp(dp, historical_bogus_partition_table_fixed,
123 sizeof historical_bogus_partition_table_fixed))) {
124 /*
125 * We will not allow people to write these from "the inside",
126 * Since properly selfdestructing takes too much code. If
127 * people really want to do this, they cannot have any
128 * providers of this geom open, and in that case they can just
129 * as easily overwrite the MBR in the parent device.
130 */
131 return(EBUSY);
132 }
133 for (i = 0; i < NDOSPART; i++) {
134 /*
135 * A Protective MBR (PMBR) has a single partition of
136 * type 0xEE spanning the whole disk. Such a MBR
137 * protects a GPT on the disk from MBR tools that
138 * don't know anything about GPT. We're interpreting
139 * it a bit more loosely: any partition of type 0xEE
140 * is to be skipped as it doesn't contain any data
141 * that we should care about. We still allow other
142 * partitions to be present in the MBR. A PMBR will
143 * be handled correctly anyway.
144 */
145 if (dp[i].dp_typ == DOSPTYP_PMBR)
146 l[i] = 0;
147 else if (dp[i].dp_flag != 0 && dp[i].dp_flag != 0x80)
148 l[i] = 0;
149 else if (dp[i].dp_typ == 0)
150 l[i] = 0;
151 else
152 l[i] = (off_t)dp[i].dp_size * ms->sectorsize;
153 error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
154 (off_t)dp[i].dp_start * ms->sectorsize, l[i],
155 ms->sectorsize, "%ss%d", gp->name, 1 + i);
156 if (error)
157 return (error);
158 }
159 for (i = 0; i < NDOSPART; i++) {
160 ms->type[i] = dp[i].dp_typ;
161 g_slice_config(gp, i, G_SLICE_CONFIG_SET,
162 (off_t)dp[i].dp_start * ms->sectorsize, l[i],
163 ms->sectorsize, "%ss%d", gp->name, 1 + i);
164 }
165 bcopy(sec0, ms->sec0, 512);
166
167 /*
168 * Calculate MD5 from the first sector and use it for avoiding
169 * recursive slices creation.
170 */
171 MD5Init(&md5sum);
172 MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0));
173 MD5Final(ms->slicesum, &md5sum);
174
175 return (0);
176 }
177
178 static int
179 g_mbr_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td)
180 {
181 struct g_geom *gp;
182 struct g_mbr_softc *ms;
183 struct g_slicer *gsp;
184 struct g_consumer *cp;
185 int error, opened;
186
187 gp = pp->geom;
188 gsp = gp->softc;
189 ms = gsp->softc;
190
191 opened = 0;
192 error = 0;
193 switch(cmd) {
194 case DIOCSMBR: {
195 if (!(fflag & FWRITE))
196 return (EPERM);
197 g_topology_lock();
198 cp = LIST_FIRST(&gp->consumer);
199 if (cp->acw == 0) {
200 error = g_access(cp, 0, 1, 0);
201 if (error == 0)
202 opened = 1;
203 }
204 if (!error)
205 error = g_mbr_modify(gp, ms, data, 512);
206 if (!error)
207 error = g_write_data(cp, 0, data, 512);
208 if (opened)
209 g_access(cp, 0, -1 , 0);
210 g_topology_unlock();
211 return(error);
212 }
213 default:
214 return (ENOIOCTL);
215 }
216 }
217
218 static int
219 g_mbr_start(struct bio *bp)
220 {
221 struct g_provider *pp;
222 struct g_geom *gp;
223 struct g_mbr_softc *mp;
224 struct g_slicer *gsp;
225 int idx;
226
227 pp = bp->bio_to;
228 idx = pp->index;
229 gp = pp->geom;
230 gsp = gp->softc;
231 mp = gsp->softc;
232 if (bp->bio_cmd == BIO_GETATTR) {
233 if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
234 return (1);
235 if (g_handleattr_off_t(bp, "MBR::offset",
236 gsp->slices[idx].offset))
237 return (1);
238 if (g_handleattr(bp, "MBR::slicesum", mp->slicesum,
239 sizeof(mp->slicesum)))
240 return (1);
241 }
242
243 return (0);
244 }
245
246 static void
247 g_mbr_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
248 {
249 struct g_mbr_softc *mp;
250 struct g_slicer *gsp;
251
252 gsp = gp->softc;
253 mp = gsp->softc;
254 g_slice_dumpconf(sb, indent, gp, cp, pp);
255 if (pp != NULL) {
256 if (indent == NULL)
257 sbuf_printf(sb, " ty %d", mp->type[pp->index]);
258 else
259 sbuf_printf(sb, "%s<type>%d</type>\n", indent,
260 mp->type[pp->index]);
261 }
262 }
263
264 static struct g_geom *
265 g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist)
266 {
267 struct g_geom *gp;
268 struct g_consumer *cp;
269 int error;
270 struct g_mbr_softc *ms;
271 u_int fwsectors, sectorsize;
272 u_char *buf;
273 u_char hash[16];
274 MD5_CTX md5sum;
275
276 g_trace(G_T_TOPOLOGY, "mbr_taste(%s,%s)", mp->name, pp->name);
277 g_topology_assert();
278 if (!strcmp(pp->geom->class->name, MBR_CLASS_NAME))
279 return (NULL);
280 gp = g_slice_new(mp, NDOSPART, pp, &cp, &ms, sizeof *ms, g_mbr_start);
281 if (gp == NULL)
282 return (NULL);
283 g_topology_unlock();
284 do {
285 error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
286 if (error)
287 fwsectors = 17;
288 sectorsize = cp->provider->sectorsize;
289 if (sectorsize < 512)
290 break;
291 ms->sectorsize = sectorsize;
292 buf = g_read_data(cp, 0, sectorsize, NULL);
293 if (buf == NULL)
294 break;
295
296 /*
297 * Calculate MD5 from the first sector and use it for avoiding
298 * recursive slices creation.
299 */
300 bcopy(buf, ms->sec0, 512);
301 MD5Init(&md5sum);
302 MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0));
303 MD5Final(ms->slicesum, &md5sum);
304
305 error = g_getattr("MBR::slicesum", cp, &hash);
306 if (!error && !bcmp(ms->slicesum, hash, sizeof(hash))) {
307 g_free(buf);
308 break;
309 }
310
311 g_topology_lock();
312 g_mbr_modify(gp, ms, buf, 512);
313 g_topology_unlock();
314 g_free(buf);
315 break;
316 } while (0);
317 g_topology_lock();
318 g_access(cp, -1, 0, 0);
319 if (LIST_EMPTY(&gp->provider)) {
320 g_slice_spoiled(cp);
321 return (NULL);
322 }
323 if (!g_mbr_once) {
324 g_mbr_once = 1;
325 printf(
326 "WARNING: geom_mbr (geom %s) is deprecated, "
327 "use gpart instead.\n", gp->name);
328 }
329 return (gp);
330 }
331
332 static void
333 g_mbr_config(struct gctl_req *req, struct g_class *mp, const char *verb)
334 {
335 struct g_geom *gp;
336 struct g_consumer *cp;
337 struct g_mbr_softc *ms;
338 struct g_slicer *gsp;
339 int opened = 0, error = 0;
340 void *data;
341 int len;
342
343 g_topology_assert();
344 gp = gctl_get_geom(req, mp, "geom");
345 if (gp == NULL)
346 return;
347 if (strcmp(verb, "write MBR")) {
348 gctl_error(req, "Unknown verb");
349 return;
350 }
351 gsp = gp->softc;
352 ms = gsp->softc;
353 data = gctl_get_param(req, "data", &len);
354 if (data == NULL)
355 return;
356 if (len < 512 || (len % 512)) {
357 gctl_error(req, "Wrong request length");
358 return;
359 }
360 cp = LIST_FIRST(&gp->consumer);
361 if (cp->acw == 0) {
362 error = g_access(cp, 0, 1, 0);
363 if (error == 0)
364 opened = 1;
365 }
366 if (!error)
367 error = g_mbr_modify(gp, ms, data, len);
368 if (error)
369 gctl_error(req, "conflict with open slices");
370 if (!error)
371 error = g_write_data(cp, 0, data, len);
372 if (error)
373 gctl_error(req, "sector zero write failed");
374 if (opened)
375 g_access(cp, 0, -1 , 0);
376 return;
377 }
378
379 static struct g_class g_mbr_class = {
380 .name = MBR_CLASS_NAME,
381 .version = G_VERSION,
382 .taste = g_mbr_taste,
383 .dumpconf = g_mbr_dumpconf,
384 .ctlreq = g_mbr_config,
385 .ioctl = g_mbr_ioctl,
386 };
387
388 DECLARE_GEOM_CLASS(g_mbr_class, g_mbr);
389
390 #define NDOSEXTPART 32
391 struct g_mbrext_softc {
392 int type [NDOSEXTPART];
393 };
394
395 static int
396 g_mbrext_start(struct bio *bp)
397 {
398 struct g_provider *pp;
399 struct g_geom *gp;
400 struct g_mbrext_softc *mp;
401 struct g_slicer *gsp;
402 int idx;
403
404 pp = bp->bio_to;
405 idx = pp->index;
406 gp = pp->geom;
407 gsp = gp->softc;
408 mp = gsp->softc;
409 if (bp->bio_cmd == BIO_GETATTR) {
410 if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
411 return (1);
412 }
413 return (0);
414 }
415
416 static void
417 g_mbrext_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
418 {
419 struct g_mbrext_softc *mp;
420 struct g_slicer *gsp;
421
422 g_slice_dumpconf(sb, indent, gp, cp, pp);
423 gsp = gp->softc;
424 mp = gsp->softc;
425 if (pp != NULL) {
426 if (indent == NULL)
427 sbuf_printf(sb, " ty %d", mp->type[pp->index]);
428 else
429 sbuf_printf(sb, "%s<type>%d</type>\n", indent,
430 mp->type[pp->index]);
431 }
432 }
433
434 static struct g_geom *
435 g_mbrext_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
436 {
437 struct g_geom *gp;
438 struct g_consumer *cp;
439 int error, i, slice;
440 struct g_mbrext_softc *ms;
441 off_t off;
442 u_char *buf;
443 struct dos_partition dp[4];
444 u_int fwsectors, sectorsize;
445
446 g_trace(G_T_TOPOLOGY, "g_mbrext_taste(%s,%s)", mp->name, pp->name);
447 g_topology_assert();
448 if (strcmp(pp->geom->class->name, MBR_CLASS_NAME))
449 return (NULL);
450 gp = g_slice_new(mp, NDOSEXTPART, pp, &cp, &ms, sizeof *ms,
451 g_mbrext_start);
452 if (gp == NULL)
453 return (NULL);
454 g_topology_unlock();
455 off = 0;
456 slice = 0;
457 do {
458 error = g_getattr("MBR::type", cp, &i);
459 if (error || (i != DOSPTYP_EXT && i != DOSPTYP_EXTLBA))
460 break;
461 error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
462 if (error)
463 fwsectors = 17;
464 sectorsize = cp->provider->sectorsize;
465 if (sectorsize != 512)
466 break;
467 for (;;) {
468 buf = g_read_data(cp, off, sectorsize, NULL);
469 if (buf == NULL)
470 break;
471 if (buf[0x1fe] != 0x55 && buf[0x1ff] != 0xaa) {
472 g_free(buf);
473 break;
474 }
475 for (i = 0; i < NDOSPART; i++)
476 dos_partition_dec(
477 buf + DOSPARTOFF +
478 i * sizeof(struct dos_partition), dp + i);
479 g_free(buf);
480 if (0 && bootverbose) {
481 printf("MBREXT Slice %d on %s:\n",
482 slice + 5, gp->name);
483 g_mbr_print(0, dp);
484 g_mbr_print(1, dp + 1);
485 }
486 if ((dp[0].dp_flag & 0x7f) == 0 &&
487 dp[0].dp_size != 0 && dp[0].dp_typ != 0) {
488 g_topology_lock();
489 g_slice_config(gp, slice, G_SLICE_CONFIG_SET,
490 (((off_t)dp[0].dp_start) << 9ULL) + off,
491 ((off_t)dp[0].dp_size) << 9ULL,
492 sectorsize,
493 "%*.*s%d",
494 (int)strlen(gp->name) - 1,
495 (int)strlen(gp->name) - 1,
496 gp->name,
497 slice + 5);
498 g_topology_unlock();
499 ms->type[slice] = dp[0].dp_typ;
500 slice++;
501 }
502 if (dp[1].dp_flag != 0)
503 break;
504 if (dp[1].dp_typ != DOSPTYP_EXT &&
505 dp[1].dp_typ != DOSPTYP_EXTLBA)
506 break;
507 if (dp[1].dp_size == 0)
508 break;
509 off = ((off_t)dp[1].dp_start) << 9ULL;
510 }
511 break;
512 } while (0);
513 g_topology_lock();
514 g_access(cp, -1, 0, 0);
515 if (LIST_EMPTY(&gp->provider)) {
516 g_slice_spoiled(cp);
517 return (NULL);
518 }
519 return (gp);
520 }
521
522
523 static struct g_class g_mbrext_class = {
524 .name = MBREXT_CLASS_NAME,
525 .version = G_VERSION,
526 .taste = g_mbrext_taste,
527 .dumpconf = g_mbrext_dumpconf,
528 };
529
530 DECLARE_GEOM_CLASS(g_mbrext_class, g_mbrext);
531 MODULE_VERSION(geom_mbr, 0);
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