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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * fs/partitions/msdos.c
4 *
5 * Code extracted from drivers/block/genhd.c
6 * Copyright (C) 1991-1998 Linus Torvalds
7 *
8 * Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
9 * in the early extended-partition checks and added DM partitions
10 *
11 * Support for DiskManager v6.0x added by Mark Lord,
12 * with information provided by OnTrack. This now works for linux fdisk
13 * and LILO, as well as loadlin and bootln. Note that disks other than
14 * /dev/hda *must* have a "DOS" type 0x51 partition in the first slot (hda1).
15 *
16 * More flexible handling of extended partitions - aeb, 950831
17 *
18 * Check partition table on IDE disks for common CHS translations
19 *
20 * Re-organised Feb 1998 Russell King
21 *
22 * BSD disklabel support by Yossi Gottlieb <yogo@math.tau.ac.il>
23 * updated by Marc Espie <Marc.Espie@openbsd.org>
24 *
25 * Unixware slices support by Andrzej Krzysztofowicz <ankry@mif.pg.gda.pl>
26 * and Krzysztof G. Baranowski <kgb@knm.org.pl>
27 */
28#include <linux/msdos_fs.h>
29#include <linux/msdos_partition.h>
30
31#include "check.h"
32#include "efi.h"
33
34/*
35 * Many architectures don't like unaligned accesses, while
36 * the nr_sects and start_sect partition table entries are
37 * at a 2 (mod 4) address.
38 */
39#include <asm/unaligned.h>
40
41static inline sector_t nr_sects(struct msdos_partition *p)
42{
43 return (sector_t)get_unaligned_le32(&p->nr_sects);
44}
45
46static inline sector_t start_sect(struct msdos_partition *p)
47{
48 return (sector_t)get_unaligned_le32(&p->start_sect);
49}
50
51static inline int is_extended_partition(struct msdos_partition *p)
52{
53 return (p->sys_ind == DOS_EXTENDED_PARTITION ||
54 p->sys_ind == WIN98_EXTENDED_PARTITION ||
55 p->sys_ind == LINUX_EXTENDED_PARTITION);
56}
57
58#define MSDOS_LABEL_MAGIC1 0x55
59#define MSDOS_LABEL_MAGIC2 0xAA
60
61static inline int
62msdos_magic_present(unsigned char *p)
63{
64 return (p[0] == MSDOS_LABEL_MAGIC1 && p[1] == MSDOS_LABEL_MAGIC2);
65}
66
67/* Value is EBCDIC 'IBMA' */
68#define AIX_LABEL_MAGIC1 0xC9
69#define AIX_LABEL_MAGIC2 0xC2
70#define AIX_LABEL_MAGIC3 0xD4
71#define AIX_LABEL_MAGIC4 0xC1
72static int aix_magic_present(struct parsed_partitions *state, unsigned char *p)
73{
74 struct msdos_partition *pt = (struct msdos_partition *) (p + 0x1be);
75 Sector sect;
76 unsigned char *d;
77 int slot, ret = 0;
78
79 if (!(p[0] == AIX_LABEL_MAGIC1 &&
80 p[1] == AIX_LABEL_MAGIC2 &&
81 p[2] == AIX_LABEL_MAGIC3 &&
82 p[3] == AIX_LABEL_MAGIC4))
83 return 0;
84
85 /*
86 * Assume the partition table is valid if Linux partitions exists.
87 * Note that old Solaris/x86 partitions use the same indicator as
88 * Linux swap partitions, so we consider that a Linux partition as
89 * well.
90 */
91 for (slot = 1; slot <= 4; slot++, pt++) {
92 if (pt->sys_ind == SOLARIS_X86_PARTITION ||
93 pt->sys_ind == LINUX_RAID_PARTITION ||
94 pt->sys_ind == LINUX_DATA_PARTITION ||
95 pt->sys_ind == LINUX_LVM_PARTITION ||
96 is_extended_partition(pt))
97 return 0;
98 }
99 d = read_part_sector(state, 7, §);
100 if (d) {
101 if (d[0] == '_' && d[1] == 'L' && d[2] == 'V' && d[3] == 'M')
102 ret = 1;
103 put_dev_sector(sect);
104 }
105 return ret;
106}
107
108static void set_info(struct parsed_partitions *state, int slot,
109 u32 disksig)
110{
111 struct partition_meta_info *info = &state->parts[slot].info;
112
113 snprintf(info->uuid, sizeof(info->uuid), "%08x-%02x", disksig,
114 slot);
115 info->volname[0] = 0;
116 state->parts[slot].has_info = true;
117}
118
119/*
120 * Create devices for each logical partition in an extended partition.
121 * The logical partitions form a linked list, with each entry being
122 * a partition table with two entries. The first entry
123 * is the real data partition (with a start relative to the partition
124 * table start). The second is a pointer to the next logical partition
125 * (with a start relative to the entire extended partition).
126 * We do not create a Linux partition for the partition tables, but
127 * only for the actual data partitions.
128 */
129
130static void parse_extended(struct parsed_partitions *state,
131 sector_t first_sector, sector_t first_size,
132 u32 disksig)
133{
134 struct msdos_partition *p;
135 Sector sect;
136 unsigned char *data;
137 sector_t this_sector, this_size;
138 sector_t sector_size;
139 int loopct = 0; /* number of links followed
140 without finding a data partition */
141 int i;
142
143 sector_size = queue_logical_block_size(state->disk->queue) / 512;
144 this_sector = first_sector;
145 this_size = first_size;
146
147 while (1) {
148 if (++loopct > 100)
149 return;
150 if (state->next == state->limit)
151 return;
152 data = read_part_sector(state, this_sector, §);
153 if (!data)
154 return;
155
156 if (!msdos_magic_present(data + 510))
157 goto done;
158
159 p = (struct msdos_partition *) (data + 0x1be);
160
161 /*
162 * Usually, the first entry is the real data partition,
163 * the 2nd entry is the next extended partition, or empty,
164 * and the 3rd and 4th entries are unused.
165 * However, DRDOS sometimes has the extended partition as
166 * the first entry (when the data partition is empty),
167 * and OS/2 seems to use all four entries.
168 */
169
170 /*
171 * First process the data partition(s)
172 */
173 for (i = 0; i < 4; i++, p++) {
174 sector_t offs, size, next;
175
176 if (!nr_sects(p) || is_extended_partition(p))
177 continue;
178
179 /* Check the 3rd and 4th entries -
180 these sometimes contain random garbage */
181 offs = start_sect(p)*sector_size;
182 size = nr_sects(p)*sector_size;
183 next = this_sector + offs;
184 if (i >= 2) {
185 if (offs + size > this_size)
186 continue;
187 if (next < first_sector)
188 continue;
189 if (next + size > first_sector + first_size)
190 continue;
191 }
192
193 put_partition(state, state->next, next, size);
194 set_info(state, state->next, disksig);
195 if (p->sys_ind == LINUX_RAID_PARTITION)
196 state->parts[state->next].flags = ADDPART_FLAG_RAID;
197 loopct = 0;
198 if (++state->next == state->limit)
199 goto done;
200 }
201 /*
202 * Next, process the (first) extended partition, if present.
203 * (So far, there seems to be no reason to make
204 * parse_extended() recursive and allow a tree
205 * of extended partitions.)
206 * It should be a link to the next logical partition.
207 */
208 p -= 4;
209 for (i = 0; i < 4; i++, p++)
210 if (nr_sects(p) && is_extended_partition(p))
211 break;
212 if (i == 4)
213 goto done; /* nothing left to do */
214
215 this_sector = first_sector + start_sect(p) * sector_size;
216 this_size = nr_sects(p) * sector_size;
217 put_dev_sector(sect);
218 }
219done:
220 put_dev_sector(sect);
221}
222
223#define SOLARIS_X86_NUMSLICE 16
224#define SOLARIS_X86_VTOC_SANE (0x600DDEEEUL)
225
226struct solaris_x86_slice {
227 __le16 s_tag; /* ID tag of partition */
228 __le16 s_flag; /* permission flags */
229 __le32 s_start; /* start sector no of partition */
230 __le32 s_size; /* # of blocks in partition */
231};
232
233struct solaris_x86_vtoc {
234 unsigned int v_bootinfo[3]; /* info needed by mboot */
235 __le32 v_sanity; /* to verify vtoc sanity */
236 __le32 v_version; /* layout version */
237 char v_volume[8]; /* volume name */
238 __le16 v_sectorsz; /* sector size in bytes */
239 __le16 v_nparts; /* number of partitions */
240 unsigned int v_reserved[10]; /* free space */
241 struct solaris_x86_slice
242 v_slice[SOLARIS_X86_NUMSLICE]; /* slice headers */
243 unsigned int timestamp[SOLARIS_X86_NUMSLICE]; /* timestamp */
244 char v_asciilabel[128]; /* for compatibility */
245};
246
247/* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also
248 indicates linux swap. Be careful before believing this is Solaris. */
249
250static void parse_solaris_x86(struct parsed_partitions *state,
251 sector_t offset, sector_t size, int origin)
252{
253#ifdef CONFIG_SOLARIS_X86_PARTITION
254 Sector sect;
255 struct solaris_x86_vtoc *v;
256 int i;
257 short max_nparts;
258
259 v = read_part_sector(state, offset + 1, §);
260 if (!v)
261 return;
262 if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) {
263 put_dev_sector(sect);
264 return;
265 }
266 {
267 char tmp[1 + BDEVNAME_SIZE + 10 + 11 + 1];
268
269 snprintf(tmp, sizeof(tmp), " %s%d: <solaris:", state->name, origin);
270 strlcat(state->pp_buf, tmp, PAGE_SIZE);
271 }
272 if (le32_to_cpu(v->v_version) != 1) {
273 char tmp[64];
274
275 snprintf(tmp, sizeof(tmp), " cannot handle version %d vtoc>\n",
276 le32_to_cpu(v->v_version));
277 strlcat(state->pp_buf, tmp, PAGE_SIZE);
278 put_dev_sector(sect);
279 return;
280 }
281 /* Ensure we can handle previous case of VTOC with 8 entries gracefully */
282 max_nparts = le16_to_cpu(v->v_nparts) > 8 ? SOLARIS_X86_NUMSLICE : 8;
283 for (i = 0; i < max_nparts && state->next < state->limit; i++) {
284 struct solaris_x86_slice *s = &v->v_slice[i];
285 char tmp[3 + 10 + 1 + 1];
286
287 if (s->s_size == 0)
288 continue;
289 snprintf(tmp, sizeof(tmp), " [s%d]", i);
290 strlcat(state->pp_buf, tmp, PAGE_SIZE);
291 /* solaris partitions are relative to current MS-DOS
292 * one; must add the offset of the current partition */
293 put_partition(state, state->next++,
294 le32_to_cpu(s->s_start)+offset,
295 le32_to_cpu(s->s_size));
296 }
297 put_dev_sector(sect);
298 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
299#endif
300}
301
302/* check against BSD src/sys/sys/disklabel.h for consistency */
303#define BSD_DISKMAGIC (0x82564557UL) /* The disk magic number */
304#define BSD_MAXPARTITIONS 16
305#define OPENBSD_MAXPARTITIONS 16
306#define BSD_FS_UNUSED 0 /* disklabel unused partition entry ID */
307struct bsd_disklabel {
308 __le32 d_magic; /* the magic number */
309 __s16 d_type; /* drive type */
310 __s16 d_subtype; /* controller/d_type specific */
311 char d_typename[16]; /* type name, e.g. "eagle" */
312 char d_packname[16]; /* pack identifier */
313 __u32 d_secsize; /* # of bytes per sector */
314 __u32 d_nsectors; /* # of data sectors per track */
315 __u32 d_ntracks; /* # of tracks per cylinder */
316 __u32 d_ncylinders; /* # of data cylinders per unit */
317 __u32 d_secpercyl; /* # of data sectors per cylinder */
318 __u32 d_secperunit; /* # of data sectors per unit */
319 __u16 d_sparespertrack; /* # of spare sectors per track */
320 __u16 d_sparespercyl; /* # of spare sectors per cylinder */
321 __u32 d_acylinders; /* # of alt. cylinders per unit */
322 __u16 d_rpm; /* rotational speed */
323 __u16 d_interleave; /* hardware sector interleave */
324 __u16 d_trackskew; /* sector 0 skew, per track */
325 __u16 d_cylskew; /* sector 0 skew, per cylinder */
326 __u32 d_headswitch; /* head switch time, usec */
327 __u32 d_trkseek; /* track-to-track seek, usec */
328 __u32 d_flags; /* generic flags */
329#define NDDATA 5
330 __u32 d_drivedata[NDDATA]; /* drive-type specific information */
331#define NSPARE 5
332 __u32 d_spare[NSPARE]; /* reserved for future use */
333 __le32 d_magic2; /* the magic number (again) */
334 __le16 d_checksum; /* xor of data incl. partitions */
335
336 /* filesystem and partition information: */
337 __le16 d_npartitions; /* number of partitions in following */
338 __le32 d_bbsize; /* size of boot area at sn0, bytes */
339 __le32 d_sbsize; /* max size of fs superblock, bytes */
340 struct bsd_partition { /* the partition table */
341 __le32 p_size; /* number of sectors in partition */
342 __le32 p_offset; /* starting sector */
343 __le32 p_fsize; /* filesystem basic fragment size */
344 __u8 p_fstype; /* filesystem type, see below */
345 __u8 p_frag; /* filesystem fragments per block */
346 __le16 p_cpg; /* filesystem cylinders per group */
347 } d_partitions[BSD_MAXPARTITIONS]; /* actually may be more */
348};
349
350#if defined(CONFIG_BSD_DISKLABEL)
351/*
352 * Create devices for BSD partitions listed in a disklabel, under a
353 * dos-like partition. See parse_extended() for more information.
354 */
355static void parse_bsd(struct parsed_partitions *state,
356 sector_t offset, sector_t size, int origin, char *flavour,
357 int max_partitions)
358{
359 Sector sect;
360 struct bsd_disklabel *l;
361 struct bsd_partition *p;
362 char tmp[64];
363
364 l = read_part_sector(state, offset + 1, §);
365 if (!l)
366 return;
367 if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) {
368 put_dev_sector(sect);
369 return;
370 }
371
372 snprintf(tmp, sizeof(tmp), " %s%d: <%s:", state->name, origin, flavour);
373 strlcat(state->pp_buf, tmp, PAGE_SIZE);
374
375 if (le16_to_cpu(l->d_npartitions) < max_partitions)
376 max_partitions = le16_to_cpu(l->d_npartitions);
377 for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) {
378 sector_t bsd_start, bsd_size;
379
380 if (state->next == state->limit)
381 break;
382 if (p->p_fstype == BSD_FS_UNUSED)
383 continue;
384 bsd_start = le32_to_cpu(p->p_offset);
385 bsd_size = le32_to_cpu(p->p_size);
386 /* FreeBSD has relative offset if C partition offset is zero */
387 if (memcmp(flavour, "bsd\0", 4) == 0 &&
388 le32_to_cpu(l->d_partitions[2].p_offset) == 0)
389 bsd_start += offset;
390 if (offset == bsd_start && size == bsd_size)
391 /* full parent partition, we have it already */
392 continue;
393 if (offset > bsd_start || offset+size < bsd_start+bsd_size) {
394 strlcat(state->pp_buf, "bad subpartition - ignored\n", PAGE_SIZE);
395 continue;
396 }
397 put_partition(state, state->next++, bsd_start, bsd_size);
398 }
399 put_dev_sector(sect);
400 if (le16_to_cpu(l->d_npartitions) > max_partitions) {
401 snprintf(tmp, sizeof(tmp), " (ignored %d more)",
402 le16_to_cpu(l->d_npartitions) - max_partitions);
403 strlcat(state->pp_buf, tmp, PAGE_SIZE);
404 }
405 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
406}
407#endif
408
409static void parse_freebsd(struct parsed_partitions *state,
410 sector_t offset, sector_t size, int origin)
411{
412#ifdef CONFIG_BSD_DISKLABEL
413 parse_bsd(state, offset, size, origin, "bsd", BSD_MAXPARTITIONS);
414#endif
415}
416
417static void parse_netbsd(struct parsed_partitions *state,
418 sector_t offset, sector_t size, int origin)
419{
420#ifdef CONFIG_BSD_DISKLABEL
421 parse_bsd(state, offset, size, origin, "netbsd", BSD_MAXPARTITIONS);
422#endif
423}
424
425static void parse_openbsd(struct parsed_partitions *state,
426 sector_t offset, sector_t size, int origin)
427{
428#ifdef CONFIG_BSD_DISKLABEL
429 parse_bsd(state, offset, size, origin, "openbsd",
430 OPENBSD_MAXPARTITIONS);
431#endif
432}
433
434#define UNIXWARE_DISKMAGIC (0xCA5E600DUL) /* The disk magic number */
435#define UNIXWARE_DISKMAGIC2 (0x600DDEEEUL) /* The slice table magic nr */
436#define UNIXWARE_NUMSLICE 16
437#define UNIXWARE_FS_UNUSED 0 /* Unused slice entry ID */
438
439struct unixware_slice {
440 __le16 s_label; /* label */
441 __le16 s_flags; /* permission flags */
442 __le32 start_sect; /* starting sector */
443 __le32 nr_sects; /* number of sectors in slice */
444};
445
446struct unixware_disklabel {
447 __le32 d_type; /* drive type */
448 __le32 d_magic; /* the magic number */
449 __le32 d_version; /* version number */
450 char d_serial[12]; /* serial number of the device */
451 __le32 d_ncylinders; /* # of data cylinders per device */
452 __le32 d_ntracks; /* # of tracks per cylinder */
453 __le32 d_nsectors; /* # of data sectors per track */
454 __le32 d_secsize; /* # of bytes per sector */
455 __le32 d_part_start; /* # of first sector of this partition*/
456 __le32 d_unknown1[12]; /* ? */
457 __le32 d_alt_tbl; /* byte offset of alternate table */
458 __le32 d_alt_len; /* byte length of alternate table */
459 __le32 d_phys_cyl; /* # of physical cylinders per device */
460 __le32 d_phys_trk; /* # of physical tracks per cylinder */
461 __le32 d_phys_sec; /* # of physical sectors per track */
462 __le32 d_phys_bytes; /* # of physical bytes per sector */
463 __le32 d_unknown2; /* ? */
464 __le32 d_unknown3; /* ? */
465 __le32 d_pad[8]; /* pad */
466
467 struct unixware_vtoc {
468 __le32 v_magic; /* the magic number */
469 __le32 v_version; /* version number */
470 char v_name[8]; /* volume name */
471 __le16 v_nslices; /* # of slices */
472 __le16 v_unknown1; /* ? */
473 __le32 v_reserved[10]; /* reserved */
474 struct unixware_slice
475 v_slice[UNIXWARE_NUMSLICE]; /* slice headers */
476 } vtoc;
477}; /* 408 */
478
479/*
480 * Create devices for Unixware partitions listed in a disklabel, under a
481 * dos-like partition. See parse_extended() for more information.
482 */
483static void parse_unixware(struct parsed_partitions *state,
484 sector_t offset, sector_t size, int origin)
485{
486#ifdef CONFIG_UNIXWARE_DISKLABEL
487 Sector sect;
488 struct unixware_disklabel *l;
489 struct unixware_slice *p;
490
491 l = read_part_sector(state, offset + 29, §);
492 if (!l)
493 return;
494 if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC ||
495 le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) {
496 put_dev_sector(sect);
497 return;
498 }
499 {
500 char tmp[1 + BDEVNAME_SIZE + 10 + 12 + 1];
501
502 snprintf(tmp, sizeof(tmp), " %s%d: <unixware:", state->name, origin);
503 strlcat(state->pp_buf, tmp, PAGE_SIZE);
504 }
505 p = &l->vtoc.v_slice[1];
506 /* I omit the 0th slice as it is the same as whole disk. */
507 while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) {
508 if (state->next == state->limit)
509 break;
510
511 if (p->s_label != UNIXWARE_FS_UNUSED)
512 put_partition(state, state->next++,
513 le32_to_cpu(p->start_sect),
514 le32_to_cpu(p->nr_sects));
515 p++;
516 }
517 put_dev_sector(sect);
518 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
519#endif
520}
521
522#define MINIX_NR_SUBPARTITIONS 4
523
524/*
525 * Minix 2.0.0/2.0.2 subpartition support.
526 * Anand Krishnamurthy <anandk@wiproge.med.ge.com>
527 * Rajeev V. Pillai <rajeevvp@yahoo.com>
528 */
529static void parse_minix(struct parsed_partitions *state,
530 sector_t offset, sector_t size, int origin)
531{
532#ifdef CONFIG_MINIX_SUBPARTITION
533 Sector sect;
534 unsigned char *data;
535 struct msdos_partition *p;
536 int i;
537
538 data = read_part_sector(state, offset, §);
539 if (!data)
540 return;
541
542 p = (struct msdos_partition *)(data + 0x1be);
543
544 /* The first sector of a Minix partition can have either
545 * a secondary MBR describing its subpartitions, or
546 * the normal boot sector. */
547 if (msdos_magic_present(data + 510) &&
548 p->sys_ind == MINIX_PARTITION) { /* subpartition table present */
549 char tmp[1 + BDEVNAME_SIZE + 10 + 9 + 1];
550
551 snprintf(tmp, sizeof(tmp), " %s%d: <minix:", state->name, origin);
552 strlcat(state->pp_buf, tmp, PAGE_SIZE);
553 for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) {
554 if (state->next == state->limit)
555 break;
556 /* add each partition in use */
557 if (p->sys_ind == MINIX_PARTITION)
558 put_partition(state, state->next++,
559 start_sect(p), nr_sects(p));
560 }
561 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
562 }
563 put_dev_sector(sect);
564#endif /* CONFIG_MINIX_SUBPARTITION */
565}
566
567static struct {
568 unsigned char id;
569 void (*parse)(struct parsed_partitions *, sector_t, sector_t, int);
570} subtypes[] = {
571 {FREEBSD_PARTITION, parse_freebsd},
572 {NETBSD_PARTITION, parse_netbsd},
573 {OPENBSD_PARTITION, parse_openbsd},
574 {MINIX_PARTITION, parse_minix},
575 {UNIXWARE_PARTITION, parse_unixware},
576 {SOLARIS_X86_PARTITION, parse_solaris_x86},
577 {NEW_SOLARIS_X86_PARTITION, parse_solaris_x86},
578 {0, NULL},
579};
580
581int msdos_partition(struct parsed_partitions *state)
582{
583 sector_t sector_size;
584 Sector sect;
585 unsigned char *data;
586 struct msdos_partition *p;
587 struct fat_boot_sector *fb;
588 int slot;
589 u32 disksig;
590
591 sector_size = queue_logical_block_size(state->disk->queue) / 512;
592 data = read_part_sector(state, 0, §);
593 if (!data)
594 return -1;
595
596 /*
597 * Note order! (some AIX disks, e.g. unbootable kind,
598 * have no MSDOS 55aa)
599 */
600 if (aix_magic_present(state, data)) {
601 put_dev_sector(sect);
602#ifdef CONFIG_AIX_PARTITION
603 return aix_partition(state);
604#else
605 strlcat(state->pp_buf, " [AIX]", PAGE_SIZE);
606 return 0;
607#endif
608 }
609
610 if (!msdos_magic_present(data + 510)) {
611 put_dev_sector(sect);
612 return 0;
613 }
614
615 /*
616 * Now that the 55aa signature is present, this is probably
617 * either the boot sector of a FAT filesystem or a DOS-type
618 * partition table. Reject this in case the boot indicator
619 * is not 0 or 0x80.
620 */
621 p = (struct msdos_partition *) (data + 0x1be);
622 for (slot = 1; slot <= 4; slot++, p++) {
623 if (p->boot_ind != 0 && p->boot_ind != 0x80) {
624 /*
625 * Even without a valid boot indicator value
626 * its still possible this is valid FAT filesystem
627 * without a partition table.
628 */
629 fb = (struct fat_boot_sector *) data;
630 if (slot == 1 && fb->reserved && fb->fats
631 && fat_valid_media(fb->media)) {
632 strlcat(state->pp_buf, "\n", PAGE_SIZE);
633 put_dev_sector(sect);
634 return 1;
635 } else {
636 put_dev_sector(sect);
637 return 0;
638 }
639 }
640 }
641
642#ifdef CONFIG_EFI_PARTITION
643 p = (struct msdos_partition *) (data + 0x1be);
644 for (slot = 1 ; slot <= 4 ; slot++, p++) {
645 /* If this is an EFI GPT disk, msdos should ignore it. */
646 if (p->sys_ind == EFI_PMBR_OSTYPE_EFI_GPT) {
647 put_dev_sector(sect);
648 return 0;
649 }
650 }
651#endif
652 p = (struct msdos_partition *) (data + 0x1be);
653
654 disksig = le32_to_cpup((__le32 *)(data + 0x1b8));
655
656 /*
657 * Look for partitions in two passes:
658 * First find the primary and DOS-type extended partitions.
659 * On the second pass look inside *BSD, Unixware and Solaris partitions.
660 */
661
662 state->next = 5;
663 for (slot = 1 ; slot <= 4 ; slot++, p++) {
664 sector_t start = start_sect(p)*sector_size;
665 sector_t size = nr_sects(p)*sector_size;
666
667 if (!size)
668 continue;
669 if (is_extended_partition(p)) {
670 /*
671 * prevent someone doing mkfs or mkswap on an
672 * extended partition, but leave room for LILO
673 * FIXME: this uses one logical sector for > 512b
674 * sector, although it may not be enough/proper.
675 */
676 sector_t n = 2;
677
678 n = min(size, max(sector_size, n));
679 put_partition(state, slot, start, n);
680
681 strlcat(state->pp_buf, " <", PAGE_SIZE);
682 parse_extended(state, start, size, disksig);
683 strlcat(state->pp_buf, " >", PAGE_SIZE);
684 continue;
685 }
686 put_partition(state, slot, start, size);
687 set_info(state, slot, disksig);
688 if (p->sys_ind == LINUX_RAID_PARTITION)
689 state->parts[slot].flags = ADDPART_FLAG_RAID;
690 if (p->sys_ind == DM6_PARTITION)
691 strlcat(state->pp_buf, "[DM]", PAGE_SIZE);
692 if (p->sys_ind == EZD_PARTITION)
693 strlcat(state->pp_buf, "[EZD]", PAGE_SIZE);
694 }
695
696 strlcat(state->pp_buf, "\n", PAGE_SIZE);
697
698 /* second pass - output for each on a separate line */
699 p = (struct msdos_partition *) (0x1be + data);
700 for (slot = 1 ; slot <= 4 ; slot++, p++) {
701 unsigned char id = p->sys_ind;
702 int n;
703
704 if (!nr_sects(p))
705 continue;
706
707 for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
708 ;
709
710 if (!subtypes[n].parse)
711 continue;
712 subtypes[n].parse(state, start_sect(p) * sector_size,
713 nr_sects(p) * sector_size, slot);
714 }
715 put_dev_sector(sect);
716 return 1;
717}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * fs/partitions/msdos.c
4 *
5 * Code extracted from drivers/block/genhd.c
6 * Copyright (C) 1991-1998 Linus Torvalds
7 *
8 * Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
9 * in the early extended-partition checks and added DM partitions
10 *
11 * Support for DiskManager v6.0x added by Mark Lord,
12 * with information provided by OnTrack. This now works for linux fdisk
13 * and LILO, as well as loadlin and bootln. Note that disks other than
14 * /dev/hda *must* have a "DOS" type 0x51 partition in the first slot (hda1).
15 *
16 * More flexible handling of extended partitions - aeb, 950831
17 *
18 * Check partition table on IDE disks for common CHS translations
19 *
20 * Re-organised Feb 1998 Russell King
21 */
22#include <linux/msdos_fs.h>
23
24#include "check.h"
25#include "msdos.h"
26#include "efi.h"
27#include "aix.h"
28
29/*
30 * Many architectures don't like unaligned accesses, while
31 * the nr_sects and start_sect partition table entries are
32 * at a 2 (mod 4) address.
33 */
34#include <asm/unaligned.h>
35
36#define SYS_IND(p) get_unaligned(&p->sys_ind)
37
38static inline sector_t nr_sects(struct partition *p)
39{
40 return (sector_t)get_unaligned_le32(&p->nr_sects);
41}
42
43static inline sector_t start_sect(struct partition *p)
44{
45 return (sector_t)get_unaligned_le32(&p->start_sect);
46}
47
48static inline int is_extended_partition(struct partition *p)
49{
50 return (SYS_IND(p) == DOS_EXTENDED_PARTITION ||
51 SYS_IND(p) == WIN98_EXTENDED_PARTITION ||
52 SYS_IND(p) == LINUX_EXTENDED_PARTITION);
53}
54
55#define MSDOS_LABEL_MAGIC1 0x55
56#define MSDOS_LABEL_MAGIC2 0xAA
57
58static inline int
59msdos_magic_present(unsigned char *p)
60{
61 return (p[0] == MSDOS_LABEL_MAGIC1 && p[1] == MSDOS_LABEL_MAGIC2);
62}
63
64/* Value is EBCDIC 'IBMA' */
65#define AIX_LABEL_MAGIC1 0xC9
66#define AIX_LABEL_MAGIC2 0xC2
67#define AIX_LABEL_MAGIC3 0xD4
68#define AIX_LABEL_MAGIC4 0xC1
69static int aix_magic_present(struct parsed_partitions *state, unsigned char *p)
70{
71 struct partition *pt = (struct partition *) (p + 0x1be);
72 Sector sect;
73 unsigned char *d;
74 int slot, ret = 0;
75
76 if (!(p[0] == AIX_LABEL_MAGIC1 &&
77 p[1] == AIX_LABEL_MAGIC2 &&
78 p[2] == AIX_LABEL_MAGIC3 &&
79 p[3] == AIX_LABEL_MAGIC4))
80 return 0;
81 /* Assume the partition table is valid if Linux partitions exists */
82 for (slot = 1; slot <= 4; slot++, pt++) {
83 if (pt->sys_ind == LINUX_SWAP_PARTITION ||
84 pt->sys_ind == LINUX_RAID_PARTITION ||
85 pt->sys_ind == LINUX_DATA_PARTITION ||
86 pt->sys_ind == LINUX_LVM_PARTITION ||
87 is_extended_partition(pt))
88 return 0;
89 }
90 d = read_part_sector(state, 7, §);
91 if (d) {
92 if (d[0] == '_' && d[1] == 'L' && d[2] == 'V' && d[3] == 'M')
93 ret = 1;
94 put_dev_sector(sect);
95 }
96 return ret;
97}
98
99static void set_info(struct parsed_partitions *state, int slot,
100 u32 disksig)
101{
102 struct partition_meta_info *info = &state->parts[slot].info;
103
104 snprintf(info->uuid, sizeof(info->uuid), "%08x-%02x", disksig,
105 slot);
106 info->volname[0] = 0;
107 state->parts[slot].has_info = true;
108}
109
110/*
111 * Create devices for each logical partition in an extended partition.
112 * The logical partitions form a linked list, with each entry being
113 * a partition table with two entries. The first entry
114 * is the real data partition (with a start relative to the partition
115 * table start). The second is a pointer to the next logical partition
116 * (with a start relative to the entire extended partition).
117 * We do not create a Linux partition for the partition tables, but
118 * only for the actual data partitions.
119 */
120
121static void parse_extended(struct parsed_partitions *state,
122 sector_t first_sector, sector_t first_size,
123 u32 disksig)
124{
125 struct partition *p;
126 Sector sect;
127 unsigned char *data;
128 sector_t this_sector, this_size;
129 sector_t sector_size = bdev_logical_block_size(state->bdev) / 512;
130 int loopct = 0; /* number of links followed
131 without finding a data partition */
132 int i;
133
134 this_sector = first_sector;
135 this_size = first_size;
136
137 while (1) {
138 if (++loopct > 100)
139 return;
140 if (state->next == state->limit)
141 return;
142 data = read_part_sector(state, this_sector, §);
143 if (!data)
144 return;
145
146 if (!msdos_magic_present(data + 510))
147 goto done;
148
149 p = (struct partition *) (data + 0x1be);
150
151 /*
152 * Usually, the first entry is the real data partition,
153 * the 2nd entry is the next extended partition, or empty,
154 * and the 3rd and 4th entries are unused.
155 * However, DRDOS sometimes has the extended partition as
156 * the first entry (when the data partition is empty),
157 * and OS/2 seems to use all four entries.
158 */
159
160 /*
161 * First process the data partition(s)
162 */
163 for (i = 0; i < 4; i++, p++) {
164 sector_t offs, size, next;
165
166 if (!nr_sects(p) || is_extended_partition(p))
167 continue;
168
169 /* Check the 3rd and 4th entries -
170 these sometimes contain random garbage */
171 offs = start_sect(p)*sector_size;
172 size = nr_sects(p)*sector_size;
173 next = this_sector + offs;
174 if (i >= 2) {
175 if (offs + size > this_size)
176 continue;
177 if (next < first_sector)
178 continue;
179 if (next + size > first_sector + first_size)
180 continue;
181 }
182
183 put_partition(state, state->next, next, size);
184 set_info(state, state->next, disksig);
185 if (SYS_IND(p) == LINUX_RAID_PARTITION)
186 state->parts[state->next].flags = ADDPART_FLAG_RAID;
187 loopct = 0;
188 if (++state->next == state->limit)
189 goto done;
190 }
191 /*
192 * Next, process the (first) extended partition, if present.
193 * (So far, there seems to be no reason to make
194 * parse_extended() recursive and allow a tree
195 * of extended partitions.)
196 * It should be a link to the next logical partition.
197 */
198 p -= 4;
199 for (i = 0; i < 4; i++, p++)
200 if (nr_sects(p) && is_extended_partition(p))
201 break;
202 if (i == 4)
203 goto done; /* nothing left to do */
204
205 this_sector = first_sector + start_sect(p) * sector_size;
206 this_size = nr_sects(p) * sector_size;
207 put_dev_sector(sect);
208 }
209done:
210 put_dev_sector(sect);
211}
212
213/* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also
214 indicates linux swap. Be careful before believing this is Solaris. */
215
216static void parse_solaris_x86(struct parsed_partitions *state,
217 sector_t offset, sector_t size, int origin)
218{
219#ifdef CONFIG_SOLARIS_X86_PARTITION
220 Sector sect;
221 struct solaris_x86_vtoc *v;
222 int i;
223 short max_nparts;
224
225 v = read_part_sector(state, offset + 1, §);
226 if (!v)
227 return;
228 if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) {
229 put_dev_sector(sect);
230 return;
231 }
232 {
233 char tmp[1 + BDEVNAME_SIZE + 10 + 11 + 1];
234
235 snprintf(tmp, sizeof(tmp), " %s%d: <solaris:", state->name, origin);
236 strlcat(state->pp_buf, tmp, PAGE_SIZE);
237 }
238 if (le32_to_cpu(v->v_version) != 1) {
239 char tmp[64];
240
241 snprintf(tmp, sizeof(tmp), " cannot handle version %d vtoc>\n",
242 le32_to_cpu(v->v_version));
243 strlcat(state->pp_buf, tmp, PAGE_SIZE);
244 put_dev_sector(sect);
245 return;
246 }
247 /* Ensure we can handle previous case of VTOC with 8 entries gracefully */
248 max_nparts = le16_to_cpu(v->v_nparts) > 8 ? SOLARIS_X86_NUMSLICE : 8;
249 for (i = 0; i < max_nparts && state->next < state->limit; i++) {
250 struct solaris_x86_slice *s = &v->v_slice[i];
251 char tmp[3 + 10 + 1 + 1];
252
253 if (s->s_size == 0)
254 continue;
255 snprintf(tmp, sizeof(tmp), " [s%d]", i);
256 strlcat(state->pp_buf, tmp, PAGE_SIZE);
257 /* solaris partitions are relative to current MS-DOS
258 * one; must add the offset of the current partition */
259 put_partition(state, state->next++,
260 le32_to_cpu(s->s_start)+offset,
261 le32_to_cpu(s->s_size));
262 }
263 put_dev_sector(sect);
264 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
265#endif
266}
267
268#if defined(CONFIG_BSD_DISKLABEL)
269/*
270 * Create devices for BSD partitions listed in a disklabel, under a
271 * dos-like partition. See parse_extended() for more information.
272 */
273static void parse_bsd(struct parsed_partitions *state,
274 sector_t offset, sector_t size, int origin, char *flavour,
275 int max_partitions)
276{
277 Sector sect;
278 struct bsd_disklabel *l;
279 struct bsd_partition *p;
280 char tmp[64];
281
282 l = read_part_sector(state, offset + 1, §);
283 if (!l)
284 return;
285 if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) {
286 put_dev_sector(sect);
287 return;
288 }
289
290 snprintf(tmp, sizeof(tmp), " %s%d: <%s:", state->name, origin, flavour);
291 strlcat(state->pp_buf, tmp, PAGE_SIZE);
292
293 if (le16_to_cpu(l->d_npartitions) < max_partitions)
294 max_partitions = le16_to_cpu(l->d_npartitions);
295 for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) {
296 sector_t bsd_start, bsd_size;
297
298 if (state->next == state->limit)
299 break;
300 if (p->p_fstype == BSD_FS_UNUSED)
301 continue;
302 bsd_start = le32_to_cpu(p->p_offset);
303 bsd_size = le32_to_cpu(p->p_size);
304 /* FreeBSD has relative offset if C partition offset is zero */
305 if (memcmp(flavour, "bsd\0", 4) == 0 &&
306 le32_to_cpu(l->d_partitions[2].p_offset) == 0)
307 bsd_start += offset;
308 if (offset == bsd_start && size == bsd_size)
309 /* full parent partition, we have it already */
310 continue;
311 if (offset > bsd_start || offset+size < bsd_start+bsd_size) {
312 strlcat(state->pp_buf, "bad subpartition - ignored\n", PAGE_SIZE);
313 continue;
314 }
315 put_partition(state, state->next++, bsd_start, bsd_size);
316 }
317 put_dev_sector(sect);
318 if (le16_to_cpu(l->d_npartitions) > max_partitions) {
319 snprintf(tmp, sizeof(tmp), " (ignored %d more)",
320 le16_to_cpu(l->d_npartitions) - max_partitions);
321 strlcat(state->pp_buf, tmp, PAGE_SIZE);
322 }
323 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
324}
325#endif
326
327static void parse_freebsd(struct parsed_partitions *state,
328 sector_t offset, sector_t size, int origin)
329{
330#ifdef CONFIG_BSD_DISKLABEL
331 parse_bsd(state, offset, size, origin, "bsd", BSD_MAXPARTITIONS);
332#endif
333}
334
335static void parse_netbsd(struct parsed_partitions *state,
336 sector_t offset, sector_t size, int origin)
337{
338#ifdef CONFIG_BSD_DISKLABEL
339 parse_bsd(state, offset, size, origin, "netbsd", BSD_MAXPARTITIONS);
340#endif
341}
342
343static void parse_openbsd(struct parsed_partitions *state,
344 sector_t offset, sector_t size, int origin)
345{
346#ifdef CONFIG_BSD_DISKLABEL
347 parse_bsd(state, offset, size, origin, "openbsd",
348 OPENBSD_MAXPARTITIONS);
349#endif
350}
351
352/*
353 * Create devices for Unixware partitions listed in a disklabel, under a
354 * dos-like partition. See parse_extended() for more information.
355 */
356static void parse_unixware(struct parsed_partitions *state,
357 sector_t offset, sector_t size, int origin)
358{
359#ifdef CONFIG_UNIXWARE_DISKLABEL
360 Sector sect;
361 struct unixware_disklabel *l;
362 struct unixware_slice *p;
363
364 l = read_part_sector(state, offset + 29, §);
365 if (!l)
366 return;
367 if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC ||
368 le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) {
369 put_dev_sector(sect);
370 return;
371 }
372 {
373 char tmp[1 + BDEVNAME_SIZE + 10 + 12 + 1];
374
375 snprintf(tmp, sizeof(tmp), " %s%d: <unixware:", state->name, origin);
376 strlcat(state->pp_buf, tmp, PAGE_SIZE);
377 }
378 p = &l->vtoc.v_slice[1];
379 /* I omit the 0th slice as it is the same as whole disk. */
380 while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) {
381 if (state->next == state->limit)
382 break;
383
384 if (p->s_label != UNIXWARE_FS_UNUSED)
385 put_partition(state, state->next++,
386 le32_to_cpu(p->start_sect),
387 le32_to_cpu(p->nr_sects));
388 p++;
389 }
390 put_dev_sector(sect);
391 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
392#endif
393}
394
395/*
396 * Minix 2.0.0/2.0.2 subpartition support.
397 * Anand Krishnamurthy <anandk@wiproge.med.ge.com>
398 * Rajeev V. Pillai <rajeevvp@yahoo.com>
399 */
400static void parse_minix(struct parsed_partitions *state,
401 sector_t offset, sector_t size, int origin)
402{
403#ifdef CONFIG_MINIX_SUBPARTITION
404 Sector sect;
405 unsigned char *data;
406 struct partition *p;
407 int i;
408
409 data = read_part_sector(state, offset, §);
410 if (!data)
411 return;
412
413 p = (struct partition *)(data + 0x1be);
414
415 /* The first sector of a Minix partition can have either
416 * a secondary MBR describing its subpartitions, or
417 * the normal boot sector. */
418 if (msdos_magic_present(data + 510) &&
419 SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */
420 char tmp[1 + BDEVNAME_SIZE + 10 + 9 + 1];
421
422 snprintf(tmp, sizeof(tmp), " %s%d: <minix:", state->name, origin);
423 strlcat(state->pp_buf, tmp, PAGE_SIZE);
424 for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) {
425 if (state->next == state->limit)
426 break;
427 /* add each partition in use */
428 if (SYS_IND(p) == MINIX_PARTITION)
429 put_partition(state, state->next++,
430 start_sect(p), nr_sects(p));
431 }
432 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
433 }
434 put_dev_sector(sect);
435#endif /* CONFIG_MINIX_SUBPARTITION */
436}
437
438static struct {
439 unsigned char id;
440 void (*parse)(struct parsed_partitions *, sector_t, sector_t, int);
441} subtypes[] = {
442 {FREEBSD_PARTITION, parse_freebsd},
443 {NETBSD_PARTITION, parse_netbsd},
444 {OPENBSD_PARTITION, parse_openbsd},
445 {MINIX_PARTITION, parse_minix},
446 {UNIXWARE_PARTITION, parse_unixware},
447 {SOLARIS_X86_PARTITION, parse_solaris_x86},
448 {NEW_SOLARIS_X86_PARTITION, parse_solaris_x86},
449 {0, NULL},
450};
451
452int msdos_partition(struct parsed_partitions *state)
453{
454 sector_t sector_size = bdev_logical_block_size(state->bdev) / 512;
455 Sector sect;
456 unsigned char *data;
457 struct partition *p;
458 struct fat_boot_sector *fb;
459 int slot;
460 u32 disksig;
461
462 data = read_part_sector(state, 0, §);
463 if (!data)
464 return -1;
465
466 /*
467 * Note order! (some AIX disks, e.g. unbootable kind,
468 * have no MSDOS 55aa)
469 */
470 if (aix_magic_present(state, data)) {
471 put_dev_sector(sect);
472#ifdef CONFIG_AIX_PARTITION
473 return aix_partition(state);
474#else
475 strlcat(state->pp_buf, " [AIX]", PAGE_SIZE);
476 return 0;
477#endif
478 }
479
480 if (!msdos_magic_present(data + 510)) {
481 put_dev_sector(sect);
482 return 0;
483 }
484
485 /*
486 * Now that the 55aa signature is present, this is probably
487 * either the boot sector of a FAT filesystem or a DOS-type
488 * partition table. Reject this in case the boot indicator
489 * is not 0 or 0x80.
490 */
491 p = (struct partition *) (data + 0x1be);
492 for (slot = 1; slot <= 4; slot++, p++) {
493 if (p->boot_ind != 0 && p->boot_ind != 0x80) {
494 /*
495 * Even without a valid boot inidicator value
496 * its still possible this is valid FAT filesystem
497 * without a partition table.
498 */
499 fb = (struct fat_boot_sector *) data;
500 if (slot == 1 && fb->reserved && fb->fats
501 && fat_valid_media(fb->media)) {
502 strlcat(state->pp_buf, "\n", PAGE_SIZE);
503 put_dev_sector(sect);
504 return 1;
505 } else {
506 put_dev_sector(sect);
507 return 0;
508 }
509 }
510 }
511
512#ifdef CONFIG_EFI_PARTITION
513 p = (struct partition *) (data + 0x1be);
514 for (slot = 1 ; slot <= 4 ; slot++, p++) {
515 /* If this is an EFI GPT disk, msdos should ignore it. */
516 if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) {
517 put_dev_sector(sect);
518 return 0;
519 }
520 }
521#endif
522 p = (struct partition *) (data + 0x1be);
523
524 disksig = le32_to_cpup((__le32 *)(data + 0x1b8));
525
526 /*
527 * Look for partitions in two passes:
528 * First find the primary and DOS-type extended partitions.
529 * On the second pass look inside *BSD, Unixware and Solaris partitions.
530 */
531
532 state->next = 5;
533 for (slot = 1 ; slot <= 4 ; slot++, p++) {
534 sector_t start = start_sect(p)*sector_size;
535 sector_t size = nr_sects(p)*sector_size;
536
537 if (!size)
538 continue;
539 if (is_extended_partition(p)) {
540 /*
541 * prevent someone doing mkfs or mkswap on an
542 * extended partition, but leave room for LILO
543 * FIXME: this uses one logical sector for > 512b
544 * sector, although it may not be enough/proper.
545 */
546 sector_t n = 2;
547
548 n = min(size, max(sector_size, n));
549 put_partition(state, slot, start, n);
550
551 strlcat(state->pp_buf, " <", PAGE_SIZE);
552 parse_extended(state, start, size, disksig);
553 strlcat(state->pp_buf, " >", PAGE_SIZE);
554 continue;
555 }
556 put_partition(state, slot, start, size);
557 set_info(state, slot, disksig);
558 if (SYS_IND(p) == LINUX_RAID_PARTITION)
559 state->parts[slot].flags = ADDPART_FLAG_RAID;
560 if (SYS_IND(p) == DM6_PARTITION)
561 strlcat(state->pp_buf, "[DM]", PAGE_SIZE);
562 if (SYS_IND(p) == EZD_PARTITION)
563 strlcat(state->pp_buf, "[EZD]", PAGE_SIZE);
564 }
565
566 strlcat(state->pp_buf, "\n", PAGE_SIZE);
567
568 /* second pass - output for each on a separate line */
569 p = (struct partition *) (0x1be + data);
570 for (slot = 1 ; slot <= 4 ; slot++, p++) {
571 unsigned char id = SYS_IND(p);
572 int n;
573
574 if (!nr_sects(p))
575 continue;
576
577 for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
578 ;
579
580 if (!subtypes[n].parse)
581 continue;
582 subtypes[n].parse(state, start_sect(p) * sector_size,
583 nr_sects(p) * sector_size, slot);
584 }
585 put_dev_sector(sect);
586 return 1;
587}