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gpt: clean up little-endian crc32 computation

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- Remove problematic cast from *uint8_t to *uint32_t (alignment issue).
 - Remove dynamic allocation and associated error handling paths.
 - Match parameter ordering to existing grub_crypto_hash function.
This commit is contained in:
Michael Marineau 2015-07-31 15:03:11 -07:00
parent adf8c776a1
commit c78ed0bff4
1 changed files with 13 additions and 38 deletions
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51
grub-core/lib/gpt.c
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@ -122,45 +122,29 @@ grub_gpt_size_to_sectors (grub_gpt_t gpt, grub_size_t size)
return sectors;
}
static grub_err_t
grub_gpt_lecrc32 (void *data, grub_size_t len, grub_uint32_t *crc)
static void
grub_gpt_lecrc32 (grub_uint32_t *crc, const void *data, grub_size_t len)
{
grub_uint8_t *crc32_context;
grub_uint32_t crc32_val;
crc32_context = grub_zalloc (GRUB_MD_CRC32->contextsize);
if (!crc32_context)
return grub_errno;
GRUB_MD_CRC32->init (crc32_context);
GRUB_MD_CRC32->write (crc32_context, data, len);
GRUB_MD_CRC32->final (crc32_context);
grub_crypto_hash (GRUB_MD_CRC32, &crc32_val, data, len);
/* GRUB_MD_CRC32 always uses big endian, gpt is always little. */
*crc = grub_swap_bytes32 (*(grub_uint32_t *)
GRUB_MD_CRC32->read (crc32_context));
grub_free (crc32_context);
return GRUB_ERR_NONE;
*crc = grub_swap_bytes32 (crc32_val);
}
static grub_err_t
grub_gpt_header_lecrc32 (struct grub_gpt_header *header, grub_uint32_t *crc)
static void
grub_gpt_header_lecrc32 (grub_uint32_t *crc, struct grub_gpt_header *header)
{
grub_uint32_t old, new;
grub_err_t err;
/* crc32 must be computed with the field cleared. */
old = header->crc32;
header->crc32 = 0;
err = grub_gpt_lecrc32 (header, sizeof (*header), &new);
grub_gpt_lecrc32 (&new, header, sizeof (*header));
header->crc32 = old;
if (err)
return err;
*crc = new;
return GRUB_ERR_NONE;
}
/* Make sure the MBR is a protective MBR and not a normal MBR. */
@ -192,9 +176,7 @@ grub_gpt_header_check (struct grub_gpt_header *gpt,
if (gpt->version != GRUB_GPT_HEADER_VERSION)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "unknown GPT version");
if (grub_gpt_header_lecrc32 (gpt, &crc))
return grub_errno;
grub_gpt_header_lecrc32 (&crc, gpt);
if (gpt->crc32 != crc)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "invalid GPT header crc32");
@ -289,9 +271,7 @@ grub_gpt_read_entries (grub_disk_t disk, grub_gpt_t gpt,
if (grub_disk_read (disk, addr, 0, entries_size, entries))
goto fail;
if (grub_gpt_lecrc32 (entries, entries_size, &crc))
goto fail;
grub_gpt_lecrc32 (&crc, entries, entries_size);
if (crc != header->partentry_crc32)
{
grub_error (GRUB_ERR_BAD_PART_TABLE, "invalid GPT entry crc32");
@ -433,17 +413,12 @@ grub_gpt_update_checksums (grub_gpt_t gpt)
gpt->backup.headersize =
grub_cpu_to_le32_compile_time (sizeof (gpt->backup));
if (grub_gpt_lecrc32 (gpt->entries, gpt->entries_size, &crc))
return grub_errno;
grub_gpt_lecrc32 (&crc, gpt->entries, gpt->entries_size);
gpt->primary.partentry_crc32 = crc;
gpt->backup.partentry_crc32 = crc;
if (grub_gpt_header_lecrc32 (&gpt->primary, &gpt->primary.crc32))
return grub_errno;
if (grub_gpt_header_lecrc32 (&gpt->backup, &gpt->backup.crc32))
return grub_errno;
grub_gpt_header_lecrc32 (&gpt->primary.crc32, &gpt->primary);
grub_gpt_header_lecrc32 (&gpt->backup.crc32, &gpt->backup);
return GRUB_ERR_NONE;
}