Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_mbr.c
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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/9.0/sys/geom/geom_mbr.c 219029 2011-02-25 10:24:35Z netchild $"); 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 49 #include <sys/diskmbr.h> 50 #include <sys/sbuf.h> 51 #include <geom/geom.h> 52 #include <geom/geom_slice.h> 53 54 FEATURE(geom_mbr, "GEOM DOS/MBR partitioning support"); 55 56 #define MBR_CLASS_NAME "MBR" 57 #define MBREXT_CLASS_NAME "MBREXT" 58 59 static struct dos_partition historical_bogus_partition_table[NDOSPART] = { 60 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, }, 61 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, }, 62 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, }, 63 { 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, }, 64 }; 65 66 static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = { 67 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, }, 68 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, }, 69 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, }, 70 { 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, }, 71 }; 72 73 static void 74 g_mbr_print(int i, struct dos_partition *dp) 75 { 76 77 printf("[%d] f:%02x typ:%d", i, dp->dp_flag, dp->dp_typ); 78 printf(" s(CHS):%d/%d/%d", DPCYL(dp->dp_scyl, dp->dp_ssect), 79 dp->dp_shd, DPSECT(dp->dp_ssect)); 80 printf(" e(CHS):%d/%d/%d", DPCYL(dp->dp_ecyl, dp->dp_esect), 81 dp->dp_ehd, DPSECT(dp->dp_esect)); 82 printf(" s:%d l:%d\n", dp->dp_start, dp->dp_size); 83 } 84 85 struct g_mbr_softc { 86 int type [NDOSPART]; 87 u_int sectorsize; 88 u_char sec0[512]; 89 u_char slicesum[16]; 90 }; 91 92 /* 93 * XXX: Add gctl_req arg and give good error msgs. 94 * XXX: Check that length argument does not bring boot code inside any slice. 95 */ 96 static int 97 g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, u_char *sec0, int len __unused) 98 { 99 int i, error; 100 off_t l[NDOSPART]; 101 struct dos_partition ndp[NDOSPART], *dp; 102 MD5_CTX md5sum; 103 104 g_topology_assert(); 105 106 if (sec0[0x1fe] != 0x55 && sec0[0x1ff] != 0xaa) 107 return (EBUSY); 108 109 dp = ndp; 110 for (i = 0; i < NDOSPART; i++) { 111 dos_partition_dec( 112 sec0 + DOSPARTOFF + i * sizeof(struct dos_partition), 113 dp + i); 114 } 115 if ((!bcmp(dp, historical_bogus_partition_table, 116 sizeof historical_bogus_partition_table)) || 117 (!bcmp(dp, historical_bogus_partition_table_fixed, 118 sizeof historical_bogus_partition_table_fixed))) { 119 /* 120 * We will not allow people to write these from "the inside", 121 * Since properly selfdestructing takes too much code. If 122 * people really want to do this, they cannot have any 123 * providers of this geom open, and in that case they can just 124 * as easily overwrite the MBR in the parent device. 125 */ 126 return(EBUSY); 127 } 128 for (i = 0; i < NDOSPART; i++) { 129 /* 130 * A Protective MBR (PMBR) has a single partition of 131 * type 0xEE spanning the whole disk. Such a MBR 132 * protects a GPT on the disk from MBR tools that 133 * don't know anything about GPT. We're interpreting 134 * it a bit more loosely: any partition of type 0xEE 135 * is to be skipped as it doesn't contain any data 136 * that we should care about. We still allow other 137 * partitions to be present in the MBR. A PMBR will 138 * be handled correctly anyway. 139 */ 140 if (dp[i].dp_typ == DOSPTYP_PMBR) 141 l[i] = 0; 142 else if (dp[i].dp_flag != 0 && dp[i].dp_flag != 0x80) 143 l[i] = 0; 144 else if (dp[i].dp_typ == 0) 145 l[i] = 0; 146 else 147 l[i] = (off_t)dp[i].dp_size * ms->sectorsize; 148 error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK, 149 (off_t)dp[i].dp_start * ms->sectorsize, l[i], 150 ms->sectorsize, "%ss%d", gp->name, 1 + i); 151 if (error) 152 return (error); 153 } 154 for (i = 0; i < NDOSPART; i++) { 155 ms->type[i] = dp[i].dp_typ; 156 g_slice_config(gp, i, G_SLICE_CONFIG_SET, 157 (off_t)dp[i].dp_start * ms->sectorsize, l[i], 158 ms->sectorsize, "%ss%d", gp->name, 1 + i); 159 } 160 bcopy(sec0, ms->sec0, 512); 161 162 /* 163 * Calculate MD5 from the first sector and use it for avoiding 164 * recursive slices creation. 165 */ 166 MD5Init(&md5sum); 167 MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0)); 168 MD5Final(ms->slicesum, &md5sum); 169 170 return (0); 171 } 172 173 static int 174 g_mbr_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td) 175 { 176 struct g_geom *gp; 177 struct g_mbr_softc *ms; 178 struct g_slicer *gsp; 179 struct g_consumer *cp; 180 int error, opened; 181 182 gp = pp->geom; 183 gsp = gp->softc; 184 ms = gsp->softc; 185 186 opened = 0; 187 error = 0; 188 switch(cmd) { 189 case DIOCSMBR: { 190 if (!(fflag & FWRITE)) 191 return (EPERM); 192 DROP_GIANT(); 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 PICKUP_GIANT(); 208 return(error); 209 } 210 default: 211 return (ENOIOCTL); 212 } 213 } 214 215 static int 216 g_mbr_start(struct bio *bp) 217 { 218 struct g_provider *pp; 219 struct g_geom *gp; 220 struct g_mbr_softc *mp; 221 struct g_slicer *gsp; 222 int idx; 223 224 pp = bp->bio_to; 225 idx = pp->index; 226 gp = pp->geom; 227 gsp = gp->softc; 228 mp = gsp->softc; 229 if (bp->bio_cmd == BIO_GETATTR) { 230 if (g_handleattr_int(bp, "MBR::type", mp->type[idx])) 231 return (1); 232 if (g_handleattr_off_t(bp, "MBR::offset", 233 gsp->slices[idx].offset)) 234 return (1); 235 if (g_handleattr(bp, "MBR::slicesum", mp->slicesum, 236 sizeof(mp->slicesum))) 237 return (1); 238 } 239 240 return (0); 241 } 242 243 static void 244 g_mbr_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp) 245 { 246 struct g_mbr_softc *mp; 247 struct g_slicer *gsp; 248 249 gsp = gp->softc; 250 mp = gsp->softc; 251 g_slice_dumpconf(sb, indent, gp, cp, pp); 252 if (pp != NULL) { 253 if (indent == NULL) 254 sbuf_printf(sb, " ty %d", mp->type[pp->index]); 255 else 256 sbuf_printf(sb, "%s<type>%d</type>\n", indent, 257 mp->type[pp->index]); 258 } 259 } 260 261 static struct g_geom * 262 g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist) 263 { 264 struct g_geom *gp; 265 struct g_consumer *cp; 266 int error; 267 struct g_mbr_softc *ms; 268 u_int fwsectors, sectorsize; 269 u_char *buf; 270 u_char hash[16]; 271 MD5_CTX md5sum; 272 273 g_trace(G_T_TOPOLOGY, "mbr_taste(%s,%s)", mp->name, pp->name); 274 g_topology_assert(); 275 if (!strcmp(pp->geom->class->name, MBR_CLASS_NAME)) 276 return (NULL); 277 gp = g_slice_new(mp, NDOSPART, pp, &cp, &ms, sizeof *ms, g_mbr_start); 278 if (gp == NULL) 279 return (NULL); 280 g_topology_unlock(); 281 do { 282 error = g_getattr("GEOM::fwsectors", cp, &fwsectors); 283 if (error) 284 fwsectors = 17; 285 sectorsize = cp->provider->sectorsize; 286 if (sectorsize < 512) 287 break; 288 ms->sectorsize = sectorsize; 289 buf = g_read_data(cp, 0, sectorsize, NULL); 290 if (buf == NULL) 291 break; 292 293 /* 294 * Calculate MD5 from the first sector and use it for avoiding 295 * recursive slices creation. 296 */ 297 bcopy(buf, ms->sec0, 512); 298 MD5Init(&md5sum); 299 MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0)); 300 MD5Final(ms->slicesum, &md5sum); 301 302 error = g_getattr("MBR::slicesum", cp, &hash); 303 if (!error && !bcmp(ms->slicesum, hash, sizeof(hash))) { 304 g_free(buf); 305 break; 306 } 307 308 g_topology_lock(); 309 g_mbr_modify(gp, ms, buf, 512); 310 g_topology_unlock(); 311 g_free(buf); 312 break; 313 } while (0); 314 g_topology_lock(); 315 g_access(cp, -1, 0, 0); 316 if (LIST_EMPTY(&gp->provider)) { 317 g_slice_spoiled(cp); 318 return (NULL); 319 } 320 return (gp); 321 } 322 323 static void 324 g_mbr_config(struct gctl_req *req, struct g_class *mp, const char *verb) 325 { 326 struct g_geom *gp; 327 struct g_consumer *cp; 328 struct g_mbr_softc *ms; 329 struct g_slicer *gsp; 330 int opened = 0, error = 0; 331 void *data; 332 int len; 333 334 g_topology_assert(); 335 gp = gctl_get_geom(req, mp, "geom"); 336 if (gp == NULL) 337 return; 338 if (strcmp(verb, "write MBR")) { 339 gctl_error(req, "Unknown verb"); 340 return; 341 } 342 gsp = gp->softc; 343 ms = gsp->softc; 344 data = gctl_get_param(req, "data", &len); 345 if (data == NULL) 346 return; 347 if (len < 512 || (len % 512)) { 348 gctl_error(req, "Wrong request length"); 349 return; 350 } 351 cp = LIST_FIRST(&gp->consumer); 352 if (cp->acw == 0) { 353 error = g_access(cp, 0, 1, 0); 354 if (error == 0) 355 opened = 1; 356 } 357 if (!error) 358 error = g_mbr_modify(gp, ms, data, len); 359 if (error) 360 gctl_error(req, "conflict with open slices"); 361 if (!error) 362 error = g_write_data(cp, 0, data, len); 363 if (error) 364 gctl_error(req, "sector zero write failed"); 365 if (opened) 366 g_access(cp, 0, -1 , 0); 367 return; 368 } 369 370 static struct g_class g_mbr_class = { 371 .name = MBR_CLASS_NAME, 372 .version = G_VERSION, 373 .taste = g_mbr_taste, 374 .dumpconf = g_mbr_dumpconf, 375 .ctlreq = g_mbr_config, 376 .ioctl = g_mbr_ioctl, 377 }; 378 379 DECLARE_GEOM_CLASS(g_mbr_class, g_mbr); 380 381 #define NDOSEXTPART 32 382 struct g_mbrext_softc { 383 int type [NDOSEXTPART]; 384 }; 385 386 static int 387 g_mbrext_start(struct bio *bp) 388 { 389 struct g_provider *pp; 390 struct g_geom *gp; 391 struct g_mbrext_softc *mp; 392 struct g_slicer *gsp; 393 int idx; 394 395 pp = bp->bio_to; 396 idx = pp->index; 397 gp = pp->geom; 398 gsp = gp->softc; 399 mp = gsp->softc; 400 if (bp->bio_cmd == BIO_GETATTR) { 401 if (g_handleattr_int(bp, "MBR::type", mp->type[idx])) 402 return (1); 403 } 404 return (0); 405 } 406 407 static void 408 g_mbrext_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp) 409 { 410 struct g_mbrext_softc *mp; 411 struct g_slicer *gsp; 412 413 g_slice_dumpconf(sb, indent, gp, cp, pp); 414 gsp = gp->softc; 415 mp = gsp->softc; 416 if (pp != NULL) { 417 if (indent == NULL) 418 sbuf_printf(sb, " ty %d", mp->type[pp->index]); 419 else 420 sbuf_printf(sb, "%s<type>%d</type>\n", indent, 421 mp->type[pp->index]); 422 } 423 } 424 425 static struct g_geom * 426 g_mbrext_taste(struct g_class *mp, struct g_provider *pp, int insist __unused) 427 { 428 struct g_geom *gp; 429 struct g_consumer *cp; 430 int error, i, slice; 431 struct g_mbrext_softc *ms; 432 off_t off; 433 u_char *buf; 434 struct dos_partition dp[4]; 435 u_int fwsectors, sectorsize; 436 437 g_trace(G_T_TOPOLOGY, "g_mbrext_taste(%s,%s)", mp->name, pp->name); 438 g_topology_assert(); 439 if (strcmp(pp->geom->class->name, MBR_CLASS_NAME)) 440 return (NULL); 441 gp = g_slice_new(mp, NDOSEXTPART, pp, &cp, &ms, sizeof *ms, 442 g_mbrext_start); 443 if (gp == NULL) 444 return (NULL); 445 g_topology_unlock(); 446 off = 0; 447 slice = 0; 448 do { 449 error = g_getattr("MBR::type", cp, &i); 450 if (error || (i != DOSPTYP_EXT && i != DOSPTYP_EXTLBA)) 451 break; 452 error = g_getattr("GEOM::fwsectors", cp, &fwsectors); 453 if (error) 454 fwsectors = 17; 455 sectorsize = cp->provider->sectorsize; 456 if (sectorsize != 512) 457 break; 458 for (;;) { 459 buf = g_read_data(cp, off, sectorsize, NULL); 460 if (buf == NULL) 461 break; 462 if (buf[0x1fe] != 0x55 && buf[0x1ff] != 0xaa) { 463 g_free(buf); 464 break; 465 } 466 for (i = 0; i < NDOSPART; i++) 467 dos_partition_dec( 468 buf + DOSPARTOFF + 469 i * sizeof(struct dos_partition), dp + i); 470 g_free(buf); 471 if (0 && bootverbose) { 472 printf("MBREXT Slice %d on %s:\n", 473 slice + 5, gp->name); 474 g_mbr_print(0, dp); 475 g_mbr_print(1, dp + 1); 476 } 477 if ((dp[0].dp_flag & 0x7f) == 0 && 478 dp[0].dp_size != 0 && dp[0].dp_typ != 0) { 479 g_topology_lock(); 480 g_slice_config(gp, slice, G_SLICE_CONFIG_SET, 481 (((off_t)dp[0].dp_start) << 9ULL) + off, 482 ((off_t)dp[0].dp_size) << 9ULL, 483 sectorsize, 484 "%*.*s%d", 485 strlen(gp->name) - 1, 486 strlen(gp->name) - 1, 487 gp->name, 488 slice + 5); 489 g_topology_unlock(); 490 ms->type[slice] = dp[0].dp_typ; 491 slice++; 492 } 493 if (dp[1].dp_flag != 0) 494 break; 495 if (dp[1].dp_typ != DOSPTYP_EXT && 496 dp[1].dp_typ != DOSPTYP_EXTLBA) 497 break; 498 if (dp[1].dp_size == 0) 499 break; 500 off = ((off_t)dp[1].dp_start) << 9ULL; 501 } 502 break; 503 } while (0); 504 g_topology_lock(); 505 g_access(cp, -1, 0, 0); 506 if (LIST_EMPTY(&gp->provider)) { 507 g_slice_spoiled(cp); 508 return (NULL); 509 } 510 return (gp); 511 } 512 513 514 static struct g_class g_mbrext_class = { 515 .name = MBREXT_CLASS_NAME, 516 .version = G_VERSION, 517 .taste = g_mbrext_taste, 518 .dumpconf = g_mbrext_dumpconf, 519 }; 520 521 DECLARE_GEOM_CLASS(g_mbrext_class, g_mbrext);
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