478 lines
13 KiB
C
478 lines
13 KiB
C
/************************************************************
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* EFI GUID Partition Table handling
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*
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* http://www.uefi.org/specs/
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* http://www.intel.com/technology/efi/
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*
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* efi.[ch] by Matt Domsch <Matt_Domsch@dell.com>
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* Copyright 2000,2001,2002,2004 Dell Inc.
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*
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* Copyright (C) 2013 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
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*
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* Under GPLv2 only
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*/
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#include <common.h>
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#include <disks.h>
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#include <init.h>
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#include <asm/unaligned.h>
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#include <dma.h>
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#include <linux/ctype.h>
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#include "efi.h"
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#include "parser.h"
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static int force_gpt = IS_ENABLED(CONFIG_PARTITION_DISK_EFI_GPT_NO_FORCE);
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/**
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* efi_crc32() - EFI version of crc32 function
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* @buf: buffer to calculate crc32 of
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* @len - length of buf
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*
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* Description: Returns EFI-style CRC32 value for @buf
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*
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* This function uses the little endian Ethernet polynomial
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* but seeds the function with ~0, and xor's with ~0 at the end.
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* Note, the EFI Specification, v1.02, has a reference to
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* Dr. Dobbs Journal, May 1994 (actually it's in May 1992).
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*/
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static inline u32
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efi_crc32(const void *buf, unsigned long len)
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{
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return crc32(0, buf, len);
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}
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/**
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* last_lba(): return number of last logical block of device
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* @bdev: block device
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*
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* Description: Returns last LBA value on success, 0 on error.
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* This is stored (by sd and ide-geometry) in
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* the part[0] entry for this disk, and is the number of
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* physical sectors available on the disk.
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*/
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static u64 last_lba(struct block_device *bdev)
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{
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if (!bdev)
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return 0;
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return bdev->num_blocks;
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}
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/**
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* alloc_read_gpt_entries(): reads partition entries from disk
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* @dev_desc
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* @gpt - GPT header
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*
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* Description: Returns ptes on success, NULL on error.
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* Allocates space for PTEs based on information found in @gpt.
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* Notes: remember to free pte when you're done!
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*/
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static gpt_entry *alloc_read_gpt_entries(struct block_device *blk,
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gpt_header * pgpt_head)
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{
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size_t count = 0;
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gpt_entry *pte = NULL;
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unsigned long from, size;
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int ret;
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count = le32_to_cpu(pgpt_head->num_partition_entries) *
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le32_to_cpu(pgpt_head->sizeof_partition_entry);
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if (!count)
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return NULL;
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pte = kzalloc(count, GFP_KERNEL);
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if (!pte)
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return NULL;
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from = le64_to_cpu(pgpt_head->partition_entry_lba);
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size = count / GPT_BLOCK_SIZE;
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ret = blk->ops->read(blk, pte, from, size);
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if (ret) {
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kfree(pte);
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pte=NULL;
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return NULL;
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}
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return pte;
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}
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static inline unsigned short bdev_logical_block_size(struct block_device
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*bdev)
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{
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return SECTOR_SIZE;
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}
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/**
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* alloc_read_gpt_header(): Allocates GPT header, reads into it from disk
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* @state
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* @lba is the Logical Block Address of the partition table
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*
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* Description: returns GPT header on success, NULL on error. Allocates
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* and fills a GPT header starting at @ from @state->bdev.
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* Note: remember to free gpt when finished with it.
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*/
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static gpt_header *alloc_read_gpt_header(struct block_device *blk,
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u64 lba)
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{
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gpt_header *gpt;
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unsigned ssz = bdev_logical_block_size(blk);
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int ret;
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gpt = kzalloc(ssz, GFP_KERNEL);
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if (!gpt)
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return NULL;
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ret = blk->ops->read(blk, gpt, lba, 1);
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if (ret) {
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kfree(gpt);
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gpt=NULL;
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return NULL;
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}
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return gpt;
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}
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/**
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* is_gpt_valid() - tests one GPT header and PTEs for validity
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*
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* lba is the logical block address of the GPT header to test
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* gpt is a GPT header ptr, filled on return.
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* ptes is a PTEs ptr, filled on return.
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*
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* Description: returns 1 if valid, 0 on error.
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* If valid, returns pointers to PTEs.
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*/
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static int is_gpt_valid(struct block_device *blk, u64 lba,
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gpt_header **gpt, gpt_entry **ptes)
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{
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u32 crc, origcrc;
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u64 lastlba;
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if (!ptes)
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return 0;
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if (!(*gpt = alloc_read_gpt_header(blk, lba)))
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return 0;
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/* Check the GPT header signature */
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if (le64_to_cpu((*gpt)->signature) != GPT_HEADER_SIGNATURE) {
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dev_dbg(blk->dev, "GUID Partition Table Header signature is wrong:"
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"0x%llX != 0x%llX\n",
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(unsigned long long)le64_to_cpu((*gpt)->signature),
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(unsigned long long)GPT_HEADER_SIGNATURE);
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goto fail;
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}
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/* Check the GUID Partition Table CRC */
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origcrc = le32_to_cpu((*gpt)->header_crc32);
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(*gpt)->header_crc32 = 0;
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crc = efi_crc32((const unsigned char *) (*gpt), le32_to_cpu((*gpt)->header_size));
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if (crc != origcrc) {
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dev_dbg(blk->dev, "GUID Partition Table Header CRC is wrong: %x != %x\n",
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crc, origcrc);
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goto fail;
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}
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(*gpt)->header_crc32 = cpu_to_le32(origcrc);
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/* Check that the my_lba entry points to the LBA that contains
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* the GUID Partition Table */
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if (le64_to_cpu((*gpt)->my_lba) != lba) {
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dev_dbg(blk->dev, "GPT: my_lba incorrect: %llX != %llX\n",
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(unsigned long long)le64_to_cpu((*gpt)->my_lba),
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(unsigned long long)lba);
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goto fail;
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}
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/* Check the first_usable_lba and last_usable_lba are within the disk. */
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lastlba = last_lba(blk);
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if (le64_to_cpu((*gpt)->first_usable_lba) > lastlba) {
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dev_dbg(blk->dev, "GPT: first_usable_lba incorrect: %lld > %lld\n",
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(unsigned long long)le64_to_cpu((*gpt)->first_usable_lba),
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(unsigned long long)lastlba);
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goto fail;
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}
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if (le64_to_cpu((*gpt)->last_usable_lba) > lastlba) {
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dev_dbg(blk->dev, "GPT: last_usable_lba incorrect: %lld > %lld\n",
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(unsigned long long)le64_to_cpu((*gpt)->last_usable_lba),
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(unsigned long long)lastlba);
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goto fail;
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}
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if (!(*ptes = alloc_read_gpt_entries(blk, *gpt)))
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goto fail;
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/* Check the GUID Partition Table Entry Array CRC */
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crc = efi_crc32((const unsigned char *)*ptes,
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le32_to_cpu((*gpt)->num_partition_entries) *
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le32_to_cpu((*gpt)->sizeof_partition_entry));
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if (crc != le32_to_cpu((*gpt)->partition_entry_array_crc32)) {
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dev_dbg(blk->dev, "GUID Partitition Entry Array CRC check failed.\n");
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goto fail_ptes;
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}
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/* We're done, all's well */
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return 1;
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fail_ptes:
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kfree(*ptes);
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*ptes = NULL;
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fail:
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kfree(*gpt);
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*gpt = NULL;
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return 0;
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}
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/**
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* is_pte_valid() - tests one PTE for validity
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* @pte is the pte to check
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* @lastlba is last lba of the disk
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*
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* Description: returns 1 if valid, 0 on error.
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*/
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static inline int
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is_pte_valid(const gpt_entry *pte, const u64 lastlba)
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{
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if ((!efi_guidcmp(pte->partition_type_guid, NULL_GUID)) ||
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le64_to_cpu(pte->starting_lba) > lastlba ||
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le64_to_cpu(pte->ending_lba) > lastlba)
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return 0;
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return 1;
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}
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/**
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* compare_gpts() - Search disk for valid GPT headers and PTEs
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* @pgpt is the primary GPT header
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* @agpt is the alternate GPT header
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* @lastlba is the last LBA number
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* Description: Returns nothing. Sanity checks pgpt and agpt fields
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* and prints warnings on discrepancies.
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*
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*/
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static void
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compare_gpts(struct device_d *dev, gpt_header *pgpt, gpt_header *agpt, u64 lastlba)
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{
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int error_found = 0;
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if (!pgpt || !agpt)
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return;
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if (le64_to_cpu(pgpt->my_lba) != le64_to_cpu(agpt->alternate_lba)) {
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dev_warn(dev,
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"GPT:Primary header LBA != Alt. header alternate_lba\n");
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dev_warn(dev, "GPT:%lld != %lld\n",
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(unsigned long long)le64_to_cpu(pgpt->my_lba),
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(unsigned long long)le64_to_cpu(agpt->alternate_lba));
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error_found++;
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}
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if (le64_to_cpu(pgpt->alternate_lba) != le64_to_cpu(agpt->my_lba)) {
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dev_warn(dev,
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"GPT:Primary header alternate_lba != Alt. header my_lba\n");
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dev_warn(dev, "GPT:%lld != %lld\n",
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(unsigned long long)le64_to_cpu(pgpt->alternate_lba),
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(unsigned long long)le64_to_cpu(agpt->my_lba));
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error_found++;
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}
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if (le64_to_cpu(pgpt->first_usable_lba) !=
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le64_to_cpu(agpt->first_usable_lba)) {
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dev_warn(dev, "GPT:first_usable_lbas don't match.\n");
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dev_warn(dev, "GPT:%lld != %lld\n",
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(unsigned long long)le64_to_cpu(pgpt->first_usable_lba),
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(unsigned long long)le64_to_cpu(agpt->first_usable_lba));
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error_found++;
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}
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if (le64_to_cpu(pgpt->last_usable_lba) !=
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le64_to_cpu(agpt->last_usable_lba)) {
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dev_warn(dev, "GPT:last_usable_lbas don't match.\n");
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dev_warn(dev, "GPT:%lld != %lld\n",
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(unsigned long long)le64_to_cpu(pgpt->last_usable_lba),
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(unsigned long long)le64_to_cpu(agpt->last_usable_lba));
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error_found++;
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}
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if (efi_guidcmp(pgpt->disk_guid, agpt->disk_guid)) {
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dev_warn(dev, "GPT:disk_guids don't match.\n");
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error_found++;
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}
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if (le32_to_cpu(pgpt->num_partition_entries) !=
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le32_to_cpu(agpt->num_partition_entries)) {
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dev_warn(dev, "GPT:num_partition_entries don't match: "
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"0x%x != 0x%x\n",
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le32_to_cpu(pgpt->num_partition_entries),
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le32_to_cpu(agpt->num_partition_entries));
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error_found++;
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}
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if (le32_to_cpu(pgpt->sizeof_partition_entry) !=
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le32_to_cpu(agpt->sizeof_partition_entry)) {
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dev_warn(dev,
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"GPT:sizeof_partition_entry values don't match: "
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"0x%x != 0x%x\n",
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le32_to_cpu(pgpt->sizeof_partition_entry),
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le32_to_cpu(agpt->sizeof_partition_entry));
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error_found++;
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}
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if (le32_to_cpu(pgpt->partition_entry_array_crc32) !=
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le32_to_cpu(agpt->partition_entry_array_crc32)) {
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dev_warn(dev,
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"GPT:partition_entry_array_crc32 values don't match: "
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"0x%x != 0x%x\n",
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le32_to_cpu(pgpt->partition_entry_array_crc32),
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le32_to_cpu(agpt->partition_entry_array_crc32));
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error_found++;
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}
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if (le64_to_cpu(pgpt->alternate_lba) != lastlba) {
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dev_warn(dev,
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"GPT:Primary header thinks Alt. header is not at the end of the disk.\n");
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dev_warn(dev, "GPT:%lld != %lld\n",
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(unsigned long long)le64_to_cpu(pgpt->alternate_lba),
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(unsigned long long)lastlba);
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error_found++;
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}
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if (le64_to_cpu(agpt->my_lba) != lastlba) {
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dev_warn(dev,
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"GPT:Alternate GPT header not at the end of the disk.\n");
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dev_warn(dev, "GPT:%lld != %lld\n",
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(unsigned long long)le64_to_cpu(agpt->my_lba),
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(unsigned long long)lastlba);
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error_found++;
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}
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if (error_found)
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dev_warn(dev, "GPT: Use GNU Parted to correct GPT errors.\n");
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return;
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}
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/**
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* find_valid_gpt() - Search disk for valid GPT headers and PTEs
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* @state
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* @gpt is a GPT header ptr, filled on return.
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* @ptes is a PTEs ptr, filled on return.
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* Description: Returns 1 if valid, 0 on error.
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* If valid, returns pointers to newly allocated GPT header and PTEs.
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* Validity depends on PMBR being valid (or being overridden by the
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* 'gpt' kernel command line option) and finding either the Primary
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* GPT header and PTEs valid, or the Alternate GPT header and PTEs
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* valid. If the Primary GPT header is not valid, the Alternate GPT header
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* is not checked unless the 'gpt' kernel command line option is passed.
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* This protects against devices which misreport their size, and forces
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* the user to decide to use the Alternate GPT.
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*/
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static int find_valid_gpt(void *buf, struct block_device *blk, gpt_header **gpt,
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gpt_entry **ptes)
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{
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int good_pgpt = 0, good_agpt = 0;
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gpt_header *pgpt = NULL, *agpt = NULL;
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gpt_entry *pptes = NULL, *aptes = NULL;
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u64 lastlba;
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if (!ptes)
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return 0;
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lastlba = last_lba(blk);
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if (force_gpt) {
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/* This will be added to the EFI Spec. per Intel after v1.02. */
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if (file_detect_type(buf, SECTOR_SIZE * 2) != filetype_gpt)
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goto fail;
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}
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good_pgpt = is_gpt_valid(blk, GPT_PRIMARY_PARTITION_TABLE_LBA,
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&pgpt, &pptes);
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if (good_pgpt)
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good_agpt = is_gpt_valid(blk,
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le64_to_cpu(pgpt->alternate_lba),
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&agpt, &aptes);
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if (!good_agpt && force_gpt)
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good_agpt = is_gpt_valid(blk, lastlba, &agpt, &aptes);
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/* The obviously unsuccessful case */
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if (!good_pgpt && !good_agpt)
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goto fail;
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if (IS_ENABLED(CONFIG_PARTITION_DISK_EFI_GPT_COMPARE))
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compare_gpts(blk->dev, pgpt, agpt, lastlba);
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/* The good cases */
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if (good_pgpt) {
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*gpt = pgpt;
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*ptes = pptes;
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kfree(agpt);
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kfree(aptes);
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if (!good_agpt)
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dev_warn(blk->dev, "Alternate GPT is invalid, using primary GPT.\n");
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return 1;
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}
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else if (good_agpt) {
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*gpt = agpt;
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*ptes = aptes;
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kfree(pgpt);
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kfree(pptes);
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dev_warn(blk->dev, "Primary GPT is invalid, using alternate GPT.\n");
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return 1;
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}
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fail:
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kfree(pgpt);
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kfree(agpt);
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kfree(pptes);
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kfree(aptes);
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*gpt = NULL;
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*ptes = NULL;
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return 0;
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}
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static void part_set_efi_name(gpt_entry *pte, char *dest)
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{
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int i;
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for (i = 0; i < GPT_PARTNAME_MAX_SIZE ; i++) {
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u8 c;
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c = pte->partition_name[i] & 0xff;
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c = (c && !isprint(c)) ? '.' : c;
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dest[i] = c;
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}
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dest[i] = 0;
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}
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static void efi_partition(void *buf, struct block_device *blk,
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struct partition_desc *pd)
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{
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gpt_header *gpt = NULL;
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gpt_entry *ptes = NULL;
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int i = 0;
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int nb_part;
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struct partition *pentry;
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if (!find_valid_gpt(buf, blk, &gpt, &ptes) || !gpt || !ptes) {
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kfree(gpt);
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kfree(ptes);
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return;
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}
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nb_part = le32_to_cpu(gpt->num_partition_entries);
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for (i = 0; i < MAX_PARTITION && i < nb_part; i++) {
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if (!is_pte_valid(&ptes[i], last_lba(blk))) {
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dev_dbg(blk->dev, "Invalid pte %d\n", i);
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return;
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}
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pentry = &pd->parts[pd->used_entries];
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pentry->first_sec = le64_to_cpu(ptes[i].starting_lba);
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pentry->size = le64_to_cpu(ptes[i].ending_lba) - pentry->first_sec;
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pentry->size++;
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part_set_efi_name(&ptes[i], pentry->name);
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pd->used_entries++;
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}
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if (i > MAX_PARTITION)
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dev_warn(blk->dev, "num_partition_entries (%d) > max partition number (%d)\n",
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nb_part, MAX_PARTITION);
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}
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static struct partition_parser efi_partition_parser = {
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.parse = efi_partition,
|
|
.type = filetype_gpt,
|
|
};
|
|
|
|
static int efi_partition_init(void)
|
|
{
|
|
return partition_parser_register(&efi_partition_parser);
|
|
}
|
|
postconsole_initcall(efi_partition_init);
|