FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_mbr.c
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: src/sys/geom/geom_mbr.c,v 1.68 2005/11/30 22:15:00 sobomax Exp $");
35
36 #include <sys/param.h>
37 #include <sys/errno.h>
38 #include <sys/endian.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
41 #include <sys/fcntl.h>
42 #include <sys/malloc.h>
43 #include <sys/bio.h>
44 #include <sys/lock.h>
45 #include <sys/mutex.h>
46 #include <sys/md5.h>
47
48 #include <sys/diskmbr.h>
49 #include <sys/sbuf.h>
50 #include <geom/geom.h>
51 #include <geom/geom_slice.h>
52
53 #define MBR_CLASS_NAME "MBR"
54 #define MBREXT_CLASS_NAME "MBREXT"
55
56 static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
57 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
58 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
59 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
60 { 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
61 };
62
63 static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
64 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
65 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
66 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
67 { 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, },
68 };
69
70 static void
71 g_mbr_print(int i, struct dos_partition *dp)
72 {
73
74 printf("[%d] f:%02x typ:%d", i, dp->dp_flag, dp->dp_typ);
75 printf(" s(CHS):%d/%d/%d", DPCYL(dp->dp_scyl, dp->dp_ssect),
76 dp->dp_shd, DPSECT(dp->dp_ssect));
77 printf(" e(CHS):%d/%d/%d", DPCYL(dp->dp_ecyl, dp->dp_esect),
78 dp->dp_ehd, DPSECT(dp->dp_esect));
79 printf(" s:%d l:%d\n", dp->dp_start, dp->dp_size);
80 }
81
82 struct g_mbr_softc {
83 int type [NDOSPART];
84 u_int sectorsize;
85 u_char sec0[512];
86 u_char slicesum[16];
87 };
88
89 /*
90 * XXX: Add gctl_req arg and give good error msgs.
91 * XXX: Check that length argument does not bring boot code inside any slice.
92 */
93 static int
94 g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, u_char *sec0, int len __unused)
95 {
96 int i, error;
97 off_t l[NDOSPART];
98 struct dos_partition ndp[NDOSPART], *dp;
99 MD5_CTX md5sum;
100
101 g_topology_assert();
102
103 if (sec0[0x1fe] != 0x55 && sec0[0x1ff] != 0xaa)
104 return (EBUSY);
105
106 dp = ndp;
107 for (i = 0; i < NDOSPART; i++) {
108 dos_partition_dec(
109 sec0 + DOSPARTOFF + i * sizeof(struct dos_partition),
110 dp + i);
111 }
112 if ((!bcmp(dp, historical_bogus_partition_table,
113 sizeof historical_bogus_partition_table)) ||
114 (!bcmp(dp, historical_bogus_partition_table_fixed,
115 sizeof historical_bogus_partition_table_fixed))) {
116 /*
117 * We will not allow people to write these from "the inside",
118 * Since properly selfdestructing takes too much code. If
119 * people really want to do this, they cannot have any
120 * providers of this geom open, and in that case they can just
121 * as easily overwrite the MBR in the parent device.
122 */
123 return(EBUSY);
124 }
125 for (i = 0; i < NDOSPART; i++) {
126 /*
127 * A Protective MBR (PMBR) has a single partition of
128 * type 0xEE spanning the whole disk. Such a MBR
129 * protects a GPT on the disk from MBR tools that
130 * don't know anything about GPT. We're interpreting
131 * it a bit more loosely: any partition of type 0xEE
132 * is to be skipped as it doesn't contain any data
133 * that we should care about. We still allow other
134 * partitions to be present in the MBR. A PMBR will
135 * be handled correctly anyway.
136 */
137 if (dp[i].dp_typ == DOSPTYP_PMBR)
138 l[i] = 0;
139 else if (dp[i].dp_flag != 0 && dp[i].dp_flag != 0x80)
140 l[i] = 0;
141 else if (dp[i].dp_typ == 0)
142 l[i] = 0;
143 else
144 l[i] = (off_t)dp[i].dp_size * ms->sectorsize;
145 error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
146 (off_t)dp[i].dp_start * ms->sectorsize, l[i],
147 ms->sectorsize, "%ss%d", gp->name, 1 + i);
148 if (error)
149 return (error);
150 }
151 for (i = 0; i < NDOSPART; i++) {
152 ms->type[i] = dp[i].dp_typ;
153 g_slice_config(gp, i, G_SLICE_CONFIG_SET,
154 (off_t)dp[i].dp_start * ms->sectorsize, l[i],
155 ms->sectorsize, "%ss%d", gp->name, 1 + i);
156 }
157 bcopy(sec0, ms->sec0, 512);
158
159 /*
160 * Calculate MD5 from the first sector and use it for avoiding
161 * recursive slices creation.
162 */
163 MD5Init(&md5sum);
164 MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0));
165 MD5Final(ms->slicesum, &md5sum);
166
167 return (0);
168 }
169
170 static int
171 g_mbr_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td)
172 {
173 struct g_geom *gp;
174 struct g_mbr_softc *ms;
175 struct g_slicer *gsp;
176 struct g_consumer *cp;
177 int error, opened;
178
179 gp = pp->geom;
180 gsp = gp->softc;
181 ms = gsp->softc;
182
183 opened = 0;
184 error = 0;
185 switch(cmd) {
186 case DIOCSMBR: {
187 if (!(fflag & FWRITE))
188 return (EPERM);
189 DROP_GIANT();
190 g_topology_lock();
191 cp = LIST_FIRST(&gp->consumer);
192 if (cp->acw == 0) {
193 error = g_access(cp, 0, 1, 0);
194 if (error == 0)
195 opened = 1;
196 }
197 if (!error)
198 error = g_mbr_modify(gp, ms, data, 512);
199 if (!error)
200 error = g_write_data(cp, 0, data, 512);
201 if (opened)
202 g_access(cp, 0, -1 , 0);
203 g_topology_unlock();
204 PICKUP_GIANT();
205 return(error);
206 }
207 default:
208 return (ENOIOCTL);
209 }
210 }
211
212 static int
213 g_mbr_start(struct bio *bp)
214 {
215 struct g_provider *pp;
216 struct g_geom *gp;
217 struct g_mbr_softc *mp;
218 struct g_slicer *gsp;
219 int idx;
220
221 pp = bp->bio_to;
222 idx = pp->index;
223 gp = pp->geom;
224 gsp = gp->softc;
225 mp = gsp->softc;
226 if (bp->bio_cmd == BIO_GETATTR) {
227 if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
228 return (1);
229 if (g_handleattr_off_t(bp, "MBR::offset",
230 gsp->slices[idx].offset))
231 return (1);
232 if (g_handleattr(bp, "MBR::slicesum", mp->slicesum,
233 sizeof(mp->slicesum)))
234 return (1);
235 }
236
237 return (0);
238 }
239
240 static void
241 g_mbr_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
242 {
243 struct g_mbr_softc *mp;
244 struct g_slicer *gsp;
245
246 gsp = gp->softc;
247 mp = gsp->softc;
248 g_slice_dumpconf(sb, indent, gp, cp, pp);
249 if (pp != NULL) {
250 if (indent == NULL)
251 sbuf_printf(sb, " ty %d", mp->type[pp->index]);
252 else
253 sbuf_printf(sb, "%s<type>%d</type>\n", indent,
254 mp->type[pp->index]);
255 }
256 }
257
258 static struct g_geom *
259 g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist)
260 {
261 struct g_geom *gp;
262 struct g_consumer *cp;
263 int error;
264 struct g_mbr_softc *ms;
265 u_int fwsectors, sectorsize;
266 u_char *buf;
267 u_char hash[16];
268 MD5_CTX md5sum;
269
270 g_trace(G_T_TOPOLOGY, "mbr_taste(%s,%s)", mp->name, pp->name);
271 g_topology_assert();
272 if (!strcmp(pp->geom->class->name, MBR_CLASS_NAME))
273 return (NULL);
274 gp = g_slice_new(mp, NDOSPART, pp, &cp, &ms, sizeof *ms, g_mbr_start);
275 if (gp == NULL)
276 return (NULL);
277 g_topology_unlock();
278 do {
279 error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
280 if (error)
281 fwsectors = 17;
282 sectorsize = cp->provider->sectorsize;
283 if (sectorsize < 512)
284 break;
285 ms->sectorsize = sectorsize;
286 buf = g_read_data(cp, 0, sectorsize, NULL);
287 if (buf == NULL)
288 break;
289
290 /*
291 * Calculate MD5 from the first sector and use it for avoiding
292 * recursive slices creation.
293 */
294 bcopy(buf, ms->sec0, 512);
295 MD5Init(&md5sum);
296 MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0));
297 MD5Final(ms->slicesum, &md5sum);
298
299 error = g_getattr("MBR::slicesum", cp, &hash);
300 if (!error && !bcmp(ms->slicesum, hash, sizeof(hash))) {
301 g_free(buf);
302 break;
303 }
304
305 g_topology_lock();
306 g_mbr_modify(gp, ms, buf, 512);
307 g_topology_unlock();
308 g_free(buf);
309 break;
310 } while (0);
311 g_topology_lock();
312 g_access(cp, -1, 0, 0);
313 if (LIST_EMPTY(&gp->provider)) {
314 g_slice_spoiled(cp);
315 return (NULL);
316 }
317 return (gp);
318 }
319
320 static void
321 g_mbr_config(struct gctl_req *req, struct g_class *mp, const char *verb)
322 {
323 struct g_geom *gp;
324 struct g_consumer *cp;
325 struct g_mbr_softc *ms;
326 struct g_slicer *gsp;
327 int opened = 0, error = 0;
328 void *data;
329 int len;
330
331 g_topology_assert();
332 gp = gctl_get_geom(req, mp, "geom");
333 if (gp == NULL)
334 return;
335 if (strcmp(verb, "write MBR")) {
336 gctl_error(req, "Unknown verb");
337 return;
338 }
339 gsp = gp->softc;
340 ms = gsp->softc;
341 data = gctl_get_param(req, "data", &len);
342 if (data == NULL)
343 return;
344 if (len < 512 || (len % 512)) {
345 gctl_error(req, "Wrong request length");
346 return;
347 }
348 cp = LIST_FIRST(&gp->consumer);
349 if (cp->acw == 0) {
350 error = g_access(cp, 0, 1, 0);
351 if (error == 0)
352 opened = 1;
353 }
354 if (!error)
355 error = g_mbr_modify(gp, ms, data, len);
356 if (error)
357 gctl_error(req, "conflict with open slices");
358 if (!error)
359 error = g_write_data(cp, 0, data, len);
360 if (error)
361 gctl_error(req, "sector zero write failed");
362 if (opened)
363 g_access(cp, 0, -1 , 0);
364 return;
365 }
366
367 static struct g_class g_mbr_class = {
368 .name = MBR_CLASS_NAME,
369 .version = G_VERSION,
370 .taste = g_mbr_taste,
371 .dumpconf = g_mbr_dumpconf,
372 .ctlreq = g_mbr_config,
373 .ioctl = g_mbr_ioctl,
374 };
375
376 DECLARE_GEOM_CLASS(g_mbr_class, g_mbr);
377
378 #define NDOSEXTPART 32
379 struct g_mbrext_softc {
380 int type [NDOSEXTPART];
381 };
382
383 static int
384 g_mbrext_start(struct bio *bp)
385 {
386 struct g_provider *pp;
387 struct g_geom *gp;
388 struct g_mbrext_softc *mp;
389 struct g_slicer *gsp;
390 int idx;
391
392 pp = bp->bio_to;
393 idx = pp->index;
394 gp = pp->geom;
395 gsp = gp->softc;
396 mp = gsp->softc;
397 if (bp->bio_cmd == BIO_GETATTR) {
398 if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
399 return (1);
400 }
401 return (0);
402 }
403
404 static void
405 g_mbrext_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
406 {
407 struct g_mbrext_softc *mp;
408 struct g_slicer *gsp;
409
410 g_slice_dumpconf(sb, indent, gp, cp, pp);
411 gsp = gp->softc;
412 mp = gsp->softc;
413 if (pp != NULL) {
414 if (indent == NULL)
415 sbuf_printf(sb, " ty %d", mp->type[pp->index]);
416 else
417 sbuf_printf(sb, "%s<type>%d</type>\n", indent,
418 mp->type[pp->index]);
419 }
420 }
421
422 static struct g_geom *
423 g_mbrext_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
424 {
425 struct g_geom *gp;
426 struct g_consumer *cp;
427 int error, i, slice;
428 struct g_mbrext_softc *ms;
429 off_t off;
430 u_char *buf;
431 struct dos_partition dp[4];
432 u_int fwsectors, sectorsize;
433
434 g_trace(G_T_TOPOLOGY, "g_mbrext_taste(%s,%s)", mp->name, pp->name);
435 g_topology_assert();
436 if (strcmp(pp->geom->class->name, MBR_CLASS_NAME))
437 return (NULL);
438 gp = g_slice_new(mp, NDOSEXTPART, pp, &cp, &ms, sizeof *ms,
439 g_mbrext_start);
440 if (gp == NULL)
441 return (NULL);
442 g_topology_unlock();
443 off = 0;
444 slice = 0;
445 do {
446 error = g_getattr("MBR::type", cp, &i);
447 if (error || (i != DOSPTYP_EXT && i != DOSPTYP_EXTLBA))
448 break;
449 error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
450 if (error)
451 fwsectors = 17;
452 sectorsize = cp->provider->sectorsize;
453 if (sectorsize != 512)
454 break;
455 for (;;) {
456 buf = g_read_data(cp, off, sectorsize, NULL);
457 if (buf == NULL)
458 break;
459 if (buf[0x1fe] != 0x55 && buf[0x1ff] != 0xaa) {
460 g_free(buf);
461 break;
462 }
463 for (i = 0; i < NDOSPART; i++)
464 dos_partition_dec(
465 buf + DOSPARTOFF +
466 i * sizeof(struct dos_partition), dp + i);
467 g_free(buf);
468 if (0 && bootverbose) {
469 printf("MBREXT Slice %d on %s:\n",
470 slice + 5, gp->name);
471 g_mbr_print(0, dp);
472 g_mbr_print(1, dp + 1);
473 }
474 if ((dp[0].dp_flag & 0x7f) == 0 &&
475 dp[0].dp_size != 0 && dp[0].dp_typ != 0) {
476 g_topology_lock();
477 g_slice_config(gp, slice, G_SLICE_CONFIG_SET,
478 (((off_t)dp[0].dp_start) << 9ULL) + off,
479 ((off_t)dp[0].dp_size) << 9ULL,
480 sectorsize,
481 "%*.*s%d",
482 strlen(gp->name) - 1,
483 strlen(gp->name) - 1,
484 gp->name,
485 slice + 5);
486 g_topology_unlock();
487 ms->type[slice] = dp[0].dp_typ;
488 slice++;
489 }
490 if (dp[1].dp_flag != 0)
491 break;
492 if (dp[1].dp_typ != DOSPTYP_EXT &&
493 dp[1].dp_typ != DOSPTYP_EXTLBA)
494 break;
495 if (dp[1].dp_size == 0)
496 break;
497 off = ((off_t)dp[1].dp_start) << 9ULL;
498 }
499 break;
500 } while (0);
501 g_topology_lock();
502 g_access(cp, -1, 0, 0);
503 if (LIST_EMPTY(&gp->provider)) {
504 g_slice_spoiled(cp);
505 return (NULL);
506 }
507 return (gp);
508 }
509
510
511 static struct g_class g_mbrext_class = {
512 .name = MBREXT_CLASS_NAME,
513 .version = G_VERSION,
514 .taste = g_mbrext_taste,
515 .dumpconf = g_mbrext_dumpconf,
516 };
517
518 DECLARE_GEOM_CLASS(g_mbrext_class, g_mbrext);
519
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