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1// SPDX-License-Identifier: GPL-2.0-or-later
2/************************************************************
3 * EFI GUID Partition Table handling
4 *
5 * http://www.uefi.org/specs/
6 * http://www.intel.com/technology/efi/
7 *
8 * efi.[ch] by Matt Domsch <[email protected]>
9 * Copyright 2000,2001,2002,2004 Dell Inc.
10 *
11 * TODO:
12 *
13 * Changelog:
14 * Mon August 5th, 2013 Davidlohr Bueso <[email protected]>
15 * - detect hybrid MBRs, tighter pMBR checking & cleanups.
16 *
17 * Mon Nov 09 2004 Matt Domsch <[email protected]>
18 * - test for valid PMBR and valid PGPT before ever reading
19 * AGPT, allow override with 'gpt' kernel command line option.
20 * - check for first/last_usable_lba outside of size of disk
21 *
22 * Tue Mar 26 2002 Matt Domsch <[email protected]>
23 * - Ported to 2.5.7-pre1 and 2.5.7-dj2
24 * - Applied patch to avoid fault in alternate header handling
25 * - cleaned up find_valid_gpt
26 * - On-disk structure and copy in memory is *always* LE now -
27 * swab fields as needed
28 * - remove print_gpt_header()
29 * - only use first max_p partition entries, to keep the kernel minor number
30 * and partition numbers tied.
31 *
32 * Mon Feb 04 2002 Matt Domsch <[email protected]>
33 * - Removed __PRIPTR_PREFIX - not being used
34 *
35 * Mon Jan 14 2002 Matt Domsch <[email protected]>
36 * - Ported to 2.5.2-pre11 + library crc32 patch Linus applied
37 *
38 * Thu Dec 6 2001 Matt Domsch <[email protected]>
39 * - Added compare_gpts().
40 * - moved le_efi_guid_to_cpus() back into this file. GPT is the only
41 * thing that keeps EFI GUIDs on disk.
42 * - Changed gpt structure names and members to be simpler and more Linux-like.
43 *
44 * Wed Oct 17 2001 Matt Domsch <[email protected]>
45 * - Removed CONFIG_DEVFS_VOLUMES_UUID code entirely per Martin Wilck
46 *
47 * Wed Oct 10 2001 Matt Domsch <[email protected]>
48 * - Changed function comments to DocBook style per Andreas Dilger suggestion.
49 *
50 * Mon Oct 08 2001 Matt Domsch <[email protected]>
51 * - Change read_lba() to use the page cache per Al Viro's work.
52 * - print u64s properly on all architectures
53 * - fixed debug_printk(), now Dprintk()
54 *
55 * Mon Oct 01 2001 Matt Domsch <[email protected]>
56 * - Style cleanups
57 * - made most functions static
58 * - Endianness addition
59 * - remove test for second alternate header, as it's not per spec,
60 * and is unnecessary. There's now a method to read/write the last
61 * sector of an odd-sized disk from user space. No tools have ever
62 * been released which used this code, so it's effectively dead.
63 * - Per Asit Mallick of Intel, added a test for a valid PMBR.
64 * - Added kernel command line option 'gpt' to override valid PMBR test.
65 *
66 * Wed Jun 6 2001 Martin Wilck <[email protected]>
67 * - added devfs volume UUID support (/dev/volumes/uuids) for
68 * mounting file systems by the partition GUID.
69 *
70 * Tue Dec 5 2000 Matt Domsch <[email protected]>
71 * - Moved crc32() to linux/lib, added efi_crc32().
72 *
73 * Thu Nov 30 2000 Matt Domsch <[email protected]>
74 * - Replaced Intel's CRC32 function with an equivalent
75 * non-license-restricted version.
76 *
77 * Wed Oct 25 2000 Matt Domsch <[email protected]>
78 * - Fixed the last_lba() call to return the proper last block
79 *
80 * Thu Oct 12 2000 Matt Domsch <[email protected]>
81 * - Thanks to Andries Brouwer for his debugging assistance.
82 * - Code works, detects all the partitions.
83 *
84 ************************************************************/
85#include <linux/kernel.h>
86#include <linux/crc32.h>
87#include <linux/ctype.h>
88#include <linux/math64.h>
89#include <linux/slab.h>
90#include "check.h"
91#include "efi.h"
92
93/* This allows a kernel command line option 'gpt' to override
94 * the test for invalid PMBR. Not __initdata because reloading
95 * the partition tables happens after init too.
96 */
97static int force_gpt;
98static int __init
99force_gpt_fn(char *str)
100{
101 force_gpt = 1;
102 return 1;
103}
104__setup("gpt", force_gpt_fn);
105
106
107/**
108 * efi_crc32() - EFI version of crc32 function
109 * @buf: buffer to calculate crc32 of
110 * @len: length of buf
111 *
112 * Description: Returns EFI-style CRC32 value for @buf
113 *
114 * This function uses the little endian Ethernet polynomial
115 * but seeds the function with ~0, and xor's with ~0 at the end.
116 * Note, the EFI Specification, v1.02, has a reference to
117 * Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
118 */
119static inline u32
120efi_crc32(const void *buf, unsigned long len)
121{
122 return (crc32(~0L, buf, len) ^ ~0L);
123}
124
125/**
126 * last_lba(): return number of last logical block of device
127 * @disk: block device
128 *
129 * Description: Returns last LBA value on success, 0 on error.
130 * This is stored (by sd and ide-geometry) in
131 * the part[0] entry for this disk, and is the number of
132 * physical sectors available on the disk.
133 */
134static u64 last_lba(struct gendisk *disk)
135{
136 return div_u64(bdev_nr_bytes(disk->part0),
137 queue_logical_block_size(disk->queue)) - 1ULL;
138}
139
140static inline int pmbr_part_valid(gpt_mbr_record *part)
141{
142 if (part->os_type != EFI_PMBR_OSTYPE_EFI_GPT)
143 goto invalid;
144
145 /* set to 0x00000001 (i.e., the LBA of the GPT Partition Header) */
146 if (le32_to_cpu(part->starting_lba) != GPT_PRIMARY_PARTITION_TABLE_LBA)
147 goto invalid;
148
149 return GPT_MBR_PROTECTIVE;
150invalid:
151 return 0;
152}
153
154/**
155 * is_pmbr_valid(): test Protective MBR for validity
156 * @mbr: pointer to a legacy mbr structure
157 * @total_sectors: amount of sectors in the device
158 *
159 * Description: Checks for a valid protective or hybrid
160 * master boot record (MBR). The validity of a pMBR depends
161 * on all of the following properties:
162 * 1) MSDOS signature is in the last two bytes of the MBR
163 * 2) One partition of type 0xEE is found
164 *
165 * In addition, a hybrid MBR will have up to three additional
166 * primary partitions, which point to the same space that's
167 * marked out by up to three GPT partitions.
168 *
169 * Returns 0 upon invalid MBR, or GPT_MBR_PROTECTIVE or
170 * GPT_MBR_HYBRID depending on the device layout.
171 */
172static int is_pmbr_valid(legacy_mbr *mbr, sector_t total_sectors)
173{
174 uint32_t sz = 0;
175 int i, part = 0, ret = 0; /* invalid by default */
176
177 if (!mbr || le16_to_cpu(mbr->signature) != MSDOS_MBR_SIGNATURE)
178 goto done;
179
180 for (i = 0; i < 4; i++) {
181 ret = pmbr_part_valid(&mbr->partition_record[i]);
182 if (ret == GPT_MBR_PROTECTIVE) {
183 part = i;
184 /*
185 * Ok, we at least know that there's a protective MBR,
186 * now check if there are other partition types for
187 * hybrid MBR.
188 */
189 goto check_hybrid;
190 }
191 }
192
193 if (ret != GPT_MBR_PROTECTIVE)
194 goto done;
195check_hybrid:
196 for (i = 0; i < 4; i++)
197 if ((mbr->partition_record[i].os_type !=
198 EFI_PMBR_OSTYPE_EFI_GPT) &&
199 (mbr->partition_record[i].os_type != 0x00))
200 ret = GPT_MBR_HYBRID;
201
202 /*
203 * Protective MBRs take up the lesser of the whole disk
204 * or 2 TiB (32bit LBA), ignoring the rest of the disk.
205 * Some partitioning programs, nonetheless, choose to set
206 * the size to the maximum 32-bit limitation, disregarding
207 * the disk size.
208 *
209 * Hybrid MBRs do not necessarily comply with this.
210 *
211 * Consider a bad value here to be a warning to support dd'ing
212 * an image from a smaller disk to a larger disk.
213 */
214 if (ret == GPT_MBR_PROTECTIVE) {
215 sz = le32_to_cpu(mbr->partition_record[part].size_in_lba);
216 if (sz != (uint32_t) total_sectors - 1 && sz != 0xFFFFFFFF)
217 pr_debug("GPT: mbr size in lba (%u) different than whole disk (%u).\n",
218 sz, (uint32_t)min(total_sectors - 1, 0xFFFFFFFF));
219 }
220done:
221 return ret;
222}
223
224/**
225 * read_lba(): Read bytes from disk, starting at given LBA
226 * @state: disk parsed partitions
227 * @lba: the Logical Block Address of the partition table
228 * @buffer: destination buffer
229 * @count: bytes to read
230 *
231 * Description: Reads @count bytes from @state->disk into @buffer.
232 * Returns number of bytes read on success, 0 on error.
233 */
234static size_t read_lba(struct parsed_partitions *state,
235 u64 lba, u8 *buffer, size_t count)
236{
237 size_t totalreadcount = 0;
238 sector_t n = lba *
239 (queue_logical_block_size(state->disk->queue) / 512);
240
241 if (!buffer || lba > last_lba(state->disk))
242 return 0;
243
244 while (count) {
245 int copied = 512;
246 Sector sect;
247 unsigned char *data = read_part_sector(state, n++, &sect);
248 if (!data)
249 break;
250 if (copied > count)
251 copied = count;
252 memcpy(buffer, data, copied);
253 put_dev_sector(sect);
254 buffer += copied;
255 totalreadcount +=copied;
256 count -= copied;
257 }
258 return totalreadcount;
259}
260
261/**
262 * alloc_read_gpt_entries(): reads partition entries from disk
263 * @state: disk parsed partitions
264 * @gpt: GPT header
265 *
266 * Description: Returns ptes on success, NULL on error.
267 * Allocates space for PTEs based on information found in @gpt.
268 * Notes: remember to free pte when you're done!
269 */
270static gpt_entry *alloc_read_gpt_entries(struct parsed_partitions *state,
271 gpt_header *gpt)
272{
273 size_t count;
274 gpt_entry *pte;
275
276 if (!gpt)
277 return NULL;
278
279 count = (size_t)le32_to_cpu(gpt->num_partition_entries) *
280 le32_to_cpu(gpt->sizeof_partition_entry);
281 if (!count)
282 return NULL;
283 pte = kmalloc(count, GFP_KERNEL);
284 if (!pte)
285 return NULL;
286
287 if (read_lba(state, le64_to_cpu(gpt->partition_entry_lba),
288 (u8 *) pte, count) < count) {
289 kfree(pte);
290 pte=NULL;
291 return NULL;
292 }
293 return pte;
294}
295
296/**
297 * alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
298 * @state: disk parsed partitions
299 * @lba: the Logical Block Address of the partition table
300 *
301 * Description: returns GPT header on success, NULL on error. Allocates
302 * and fills a GPT header starting at @ from @state->disk.
303 * Note: remember to free gpt when finished with it.
304 */
305static gpt_header *alloc_read_gpt_header(struct parsed_partitions *state,
306 u64 lba)
307{
308 gpt_header *gpt;
309 unsigned ssz = queue_logical_block_size(state->disk->queue);
310
311 gpt = kmalloc(ssz, GFP_KERNEL);
312 if (!gpt)
313 return NULL;
314
315 if (read_lba(state, lba, (u8 *) gpt, ssz) < ssz) {
316 kfree(gpt);
317 gpt=NULL;
318 return NULL;
319 }
320
321 return gpt;
322}
323
324/**
325 * is_gpt_valid() - tests one GPT header and PTEs for validity
326 * @state: disk parsed partitions
327 * @lba: logical block address of the GPT header to test
328 * @gpt: GPT header ptr, filled on return.
329 * @ptes: PTEs ptr, filled on return.
330 *
331 * Description: returns 1 if valid, 0 on error.
332 * If valid, returns pointers to newly allocated GPT header and PTEs.
333 */
334static int is_gpt_valid(struct parsed_partitions *state, u64 lba,
335 gpt_header **gpt, gpt_entry **ptes)
336{
337 u32 crc, origcrc;
338 u64 lastlba, pt_size;
339
340 if (!ptes)
341 return 0;
342 if (!(*gpt = alloc_read_gpt_header(state, lba)))
343 return 0;
344
345 /* Check the GUID Partition Table signature */
346 if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
347 pr_debug("GUID Partition Table Header signature is wrong:"
348 "%lld != %lld\n",
349 (unsigned long long)le64_to_cpu((*gpt)->signature),
350 (unsigned long long)GPT_HEADER_SIGNATURE);
351 goto fail;
352 }
353
354 /* Check the GUID Partition Table header size is too big */
355 if (le32_to_cpu((*gpt)->header_size) >
356 queue_logical_block_size(state->disk->queue)) {
357 pr_debug("GUID Partition Table Header size is too large: %u > %u\n",
358 le32_to_cpu((*gpt)->header_size),
359 queue_logical_block_size(state->disk->queue));
360 goto fail;
361 }
362
363 /* Check the GUID Partition Table header size is too small */
364 if (le32_to_cpu((*gpt)->header_size) < sizeof(gpt_header)) {
365 pr_debug("GUID Partition Table Header size is too small: %u < %zu\n",
366 le32_to_cpu((*gpt)->header_size),
367 sizeof(gpt_header));
368 goto fail;
369 }
370
371 /* Check the GUID Partition Table CRC */
372 origcrc = le32_to_cpu((*gpt)->header_crc32);
373 (*gpt)->header_crc32 = 0;
374 crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
375
376 if (crc != origcrc) {
377 pr_debug("GUID Partition Table Header CRC is wrong: %x != %x\n",
378 crc, origcrc);
379 goto fail;
380 }
381 (*gpt)->header_crc32 = cpu_to_le32(origcrc);
382
383 /* Check that the my_lba entry points to the LBA that contains
384 * the GUID Partition Table */
385 if (le64_to_cpu((*gpt)->my_lba) != lba) {
386 pr_debug("GPT my_lba incorrect: %lld != %lld\n",
387 (unsigned long long)le64_to_cpu((*gpt)->my_lba),
388 (unsigned long long)lba);
389 goto fail;
390 }
391
392 /* Check the first_usable_lba and last_usable_lba are
393 * within the disk.
394 */
395 lastlba = last_lba(state->disk);
396 if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
397 pr_debug("GPT: first_usable_lba incorrect: %lld > %lld\n",
398 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
399 (unsigned long long)lastlba);
400 goto fail;
401 }
402 if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
403 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
404 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
405 (unsigned long long)lastlba);
406 goto fail;
407 }
408 if (le64_to_cpu((*gpt)->last_usable_lba) < le64_to_cpu((*gpt)->first_usable_lba)) {
409 pr_debug("GPT: last_usable_lba incorrect: %lld > %lld\n",
410 (unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
411 (unsigned long long)le64_to_cpu((*gpt)->first_usable_lba));
412 goto fail;
413 }
414 /* Check that sizeof_partition_entry has the correct value */
415 if (le32_to_cpu((*gpt)->sizeof_partition_entry) != sizeof(gpt_entry)) {
416 pr_debug("GUID Partition Entry Size check failed.\n");
417 goto fail;
418 }
419
420 /* Sanity check partition table size */
421 pt_size = (u64)le32_to_cpu((*gpt)->num_partition_entries) *
422 le32_to_cpu((*gpt)->sizeof_partition_entry);
423 if (pt_size > KMALLOC_MAX_SIZE) {
424 pr_debug("GUID Partition Table is too large: %llu > %lu bytes\n",
425 (unsigned long long)pt_size, KMALLOC_MAX_SIZE);
426 goto fail;
427 }
428
429 if (!(*ptes = alloc_read_gpt_entries(state, *gpt)))
430 goto fail;
431
432 /* Check the GUID Partition Entry Array CRC */
433 crc = efi_crc32((const unsigned char *) (*ptes), pt_size);
434
435 if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
436 pr_debug("GUID Partition Entry Array CRC check failed.\n");
437 goto fail_ptes;
438 }
439
440 /* We're done, all's well */
441 return 1;
442
443 fail_ptes:
444 kfree(*ptes);
445 *ptes = NULL;
446 fail:
447 kfree(*gpt);
448 *gpt = NULL;
449 return 0;
450}
451
452/**
453 * is_pte_valid() - tests one PTE for validity
454 * @pte:pte to check
455 * @lastlba: last lba of the disk
456 *
457 * Description: returns 1 if valid, 0 on error.
458 */
459static inline int
460is_pte_valid(const gpt_entry *pte, const u64 lastlba)
461{
462 if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
463 le64_to_cpu(pte->starting_lba) > lastlba ||
464 le64_to_cpu(pte->ending_lba) > lastlba)
465 return 0;
466 return 1;
467}
468
469/**
470 * compare_gpts() - Search disk for valid GPT headers and PTEs
471 * @pgpt: primary GPT header
472 * @agpt: alternate GPT header
473 * @lastlba: last LBA number
474 *
475 * Description: Returns nothing. Sanity checks pgpt and agpt fields
476 * and prints warnings on discrepancies.
477 *
478 */
479static void
480compare_gpts(gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
481{
482 int error_found = 0;
483 if (!pgpt || !agpt)
484 return;
485 if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
486 pr_warn("GPT:Primary header LBA != Alt. header alternate_lba\n");
487 pr_warn("GPT:%lld != %lld\n",
488 (unsigned long long)le64_to_cpu(pgpt->my_lba),
489 (unsigned long long)le64_to_cpu(agpt->alternate_lba));
490 error_found++;
491 }
492 if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
493 pr_warn("GPT:Primary header alternate_lba != Alt. header my_lba\n");
494 pr_warn("GPT:%lld != %lld\n",
495 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
496 (unsigned long long)le64_to_cpu(agpt->my_lba));
497 error_found++;
498 }
499 if (le64_to_cpu(pgpt->first_usable_lba) !=
500 le64_to_cpu(agpt->first_usable_lba)) {
501 pr_warn("GPT:first_usable_lbas don't match.\n");
502 pr_warn("GPT:%lld != %lld\n",
503 (unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
504 (unsigned long long)le64_to_cpu(agpt->first_usable_lba));
505 error_found++;
506 }
507 if (le64_to_cpu(pgpt->last_usable_lba) !=
508 le64_to_cpu(agpt->last_usable_lba)) {
509 pr_warn("GPT:last_usable_lbas don't match.\n");
510 pr_warn("GPT:%lld != %lld\n",
511 (unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
512 (unsigned long long)le64_to_cpu(agpt->last_usable_lba));
513 error_found++;
514 }
515 if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
516 pr_warn("GPT:disk_guids don't match.\n");
517 error_found++;
518 }
519 if (le32_to_cpu(pgpt->num_partition_entries) !=
520 le32_to_cpu(agpt->num_partition_entries)) {
521 pr_warn("GPT:num_partition_entries don't match: "
522 "0x%x != 0x%x\n",
523 le32_to_cpu(pgpt->num_partition_entries),
524 le32_to_cpu(agpt->num_partition_entries));
525 error_found++;
526 }
527 if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
528 le32_to_cpu(agpt->sizeof_partition_entry)) {
529 pr_warn("GPT:sizeof_partition_entry values don't match: "
530 "0x%x != 0x%x\n",
531 le32_to_cpu(pgpt->sizeof_partition_entry),
532 le32_to_cpu(agpt->sizeof_partition_entry));
533 error_found++;
534 }
535 if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
536 le32_to_cpu(agpt->partition_entry_array_crc32)) {
537 pr_warn("GPT:partition_entry_array_crc32 values don't match: "
538 "0x%x != 0x%x\n",
539 le32_to_cpu(pgpt->partition_entry_array_crc32),
540 le32_to_cpu(agpt->partition_entry_array_crc32));
541 error_found++;
542 }
543 if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
544 pr_warn("GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
545 pr_warn("GPT:%lld != %lld\n",
546 (unsigned long long)le64_to_cpu(pgpt->alternate_lba),
547 (unsigned long long)lastlba);
548 error_found++;
549 }
550
551 if (le64_to_cpu(agpt->my_lba) != lastlba) {
552 pr_warn("GPT:Alternate GPT header not at the end of the disk.\n");
553 pr_warn("GPT:%lld != %lld\n",
554 (unsigned long long)le64_to_cpu(agpt->my_lba),
555 (unsigned long long)lastlba);
556 error_found++;
557 }
558
559 if (error_found)
560 pr_warn("GPT: Use GNU Parted to correct GPT errors.\n");
561 return;
562}
563
564/**
565 * find_valid_gpt() - Search disk for valid GPT headers and PTEs
566 * @state: disk parsed partitions
567 * @gpt: GPT header ptr, filled on return.
568 * @ptes: PTEs ptr, filled on return.
569 *
570 * Description: Returns 1 if valid, 0 on error.
571 * If valid, returns pointers to newly allocated GPT header and PTEs.
572 * Validity depends on PMBR being valid (or being overridden by the
573 * 'gpt' kernel command line option) and finding either the Primary
574 * GPT header and PTEs valid, or the Alternate GPT header and PTEs
575 * valid. If the Primary GPT header is not valid, the Alternate GPT header
576 * is not checked unless the 'gpt' kernel command line option is passed.
577 * This protects against devices which misreport their size, and forces
578 * the user to decide to use the Alternate GPT.
579 */
580static int find_valid_gpt(struct parsed_partitions *state, gpt_header **gpt,
581 gpt_entry **ptes)
582{
583 int good_pgpt = 0, good_agpt = 0, good_pmbr = 0;
584 gpt_header *pgpt = NULL, *agpt = NULL;
585 gpt_entry *pptes = NULL, *aptes = NULL;
586 legacy_mbr *legacymbr;
587 struct gendisk *disk = state->disk;
588 const struct block_device_operations *fops = disk->fops;
589 sector_t total_sectors = get_capacity(state->disk);
590 u64 lastlba;
591
592 if (!ptes)
593 return 0;
594
595 lastlba = last_lba(state->disk);
596 if (!force_gpt) {
597 /* This will be added to the EFI Spec. per Intel after v1.02. */
598 legacymbr = kzalloc_obj(*legacymbr);
599 if (!legacymbr)
600 goto fail;
601
602 read_lba(state, 0, (u8 *)legacymbr, sizeof(*legacymbr));
603 good_pmbr = is_pmbr_valid(legacymbr, total_sectors);
604 kfree(legacymbr);
605
606 if (!good_pmbr)
607 goto fail;
608
609 pr_debug("Device has a %s MBR\n",
610 good_pmbr == GPT_MBR_PROTECTIVE ?
611 "protective" : "hybrid");
612 }
613
614 good_pgpt = is_gpt_valid(state, GPT_PRIMARY_PARTITION_TABLE_LBA,
615 &pgpt, &pptes);
616 if (good_pgpt)
617 good_agpt = is_gpt_valid(state,
618 le64_to_cpu(pgpt->alternate_lba),
619 &agpt, &aptes);
620 if (!good_agpt && force_gpt)
621 good_agpt = is_gpt_valid(state, lastlba, &agpt, &aptes);
622
623 if (!good_agpt && force_gpt && fops->alternative_gpt_sector) {
624 sector_t agpt_sector;
625 int err;
626
627 err = fops->alternative_gpt_sector(disk, &agpt_sector);
628 if (!err)
629 good_agpt = is_gpt_valid(state, agpt_sector,
630 &agpt, &aptes);
631 }
632
633 /* The obviously unsuccessful case */
634 if (!good_pgpt && !good_agpt)
635 goto fail;
636
637 compare_gpts(pgpt, agpt, lastlba);
638
639 /* The good cases */
640 if (good_pgpt) {
641 *gpt = pgpt;
642 *ptes = pptes;
643 kfree(agpt);
644 kfree(aptes);
645 if (!good_agpt)
646 pr_warn("Alternate GPT is invalid, using primary GPT.\n");
647 return 1;
648 }
649 else if (good_agpt) {
650 *gpt = agpt;
651 *ptes = aptes;
652 kfree(pgpt);
653 kfree(pptes);
654 pr_warn("Primary GPT is invalid, using alternate GPT.\n");
655 return 1;
656 }
657
658 fail:
659 kfree(pgpt);
660 kfree(agpt);
661 kfree(pptes);
662 kfree(aptes);
663 *gpt = NULL;
664 *ptes = NULL;
665 return 0;
666}
667
668/**
669 * utf16_le_to_7bit(): Naively converts a UTF-16LE string to 7-bit ASCII characters
670 * @in: input UTF-16LE string
671 * @size: size of the input string
672 * @out: output string ptr, should be capable to store @size+1 characters
673 *
674 * Description: Converts @size UTF16-LE symbols from @in string to 7-bit
675 * ASCII characters and stores them to @out. Adds trailing zero to @out array.
676 */
677static void utf16_le_to_7bit(const __le16 *in, unsigned int size, u8 *out)
678{
679 unsigned int i = 0;
680
681 out[size] = 0;
682
683 while (i < size) {
684 u8 c = le16_to_cpu(in[i]) & 0x7f;
685
686 if (c && !isprint(c))
687 c = '!';
688 out[i] = c;
689 i++;
690 }
691}
692
693/**
694 * efi_partition - scan for GPT partitions
695 * @state: disk parsed partitions
696 *
697 * Description: called from check.c, if the disk contains GPT
698 * partitions, sets up partition entries in the kernel.
699 *
700 * If the first block on the disk is a legacy MBR,
701 * it will get handled by msdos_partition().
702 * If it's a Protective MBR, we'll handle it here.
703 *
704 * We do not create a Linux partition for GPT, but
705 * only for the actual data partitions.
706 * Returns:
707 * -1 if unable to read the partition table
708 * 0 if this isn't our partition table
709 * 1 if successful
710 *
711 */
712int efi_partition(struct parsed_partitions *state)
713{
714 gpt_header *gpt = NULL;
715 gpt_entry *ptes = NULL;
716 u32 i;
717 unsigned ssz = queue_logical_block_size(state->disk->queue) / 512;
718
719 if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) {
720 kfree(gpt);
721 kfree(ptes);
722 return 0;
723 }
724
725 pr_debug("GUID Partition Table is valid! Yea!\n");
726
727 for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
728 struct partition_meta_info *info;
729 unsigned label_max;
730 u64 start = le64_to_cpu(ptes[i].starting_lba);
731 u64 size = le64_to_cpu(ptes[i].ending_lba) -
732 le64_to_cpu(ptes[i].starting_lba) + 1ULL;
733
734 if (!is_pte_valid(&ptes[i], last_lba(state->disk)))
735 continue;
736
737 put_partition(state, i+1, start * ssz, size * ssz);
738
739 /* If this is a RAID volume, tell md */
740 if (!efi_guidcmp(ptes[i].partition_type_guid, PARTITION_LINUX_RAID_GUID))
741 state->parts[i + 1].flags = ADDPART_FLAG_RAID;
742
743 info = &state->parts[i + 1].info;
744 efi_guid_to_str(&ptes[i].unique_partition_guid, info->uuid);
745
746 /* Naively convert UTF16-LE to 7 bits. */
747 label_max = min(ARRAY_SIZE(info->volname) - 1,
748 ARRAY_SIZE(ptes[i].partition_name));
749 utf16_le_to_7bit(ptes[i].partition_name, label_max, info->volname);
750 state->parts[i + 1].has_info = true;
751 }
752 kfree(ptes);
753 kfree(gpt);
754 seq_buf_puts(&state->pp_buf, "\n");
755 return 1;
756}