0015-gpt-clean-up-little-endian-crc32-computation.patch

From 7ed137907dfccfcd738ec7371ded51af39d48006 Mon Sep 17 00:00:00 2001
From: Michael Marineau <michael.marineau@coreos.com>
Date: Fri, 31 Jul 2015 15:03:11 -0700
Subject: [PATCH] gpt: clean up little-endian crc32 computation

 - 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.
---
 grub-core/lib/gpt.c | 51 ++++++++++++---------------------------------
 1 file changed, 13 insertions(+), 38 deletions(-)

diff --git a/grub-core/lib/gpt.c b/grub-core/lib/gpt.c
index 10a4b85..aedc4f7 100644
--- a/grub-core/lib/gpt.c
+++ b/grub-core/lib/gpt.c
@@ -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;
-
-  crc32_context = grub_zalloc (GRUB_MD_CRC32->contextsize);
-  if (!crc32_context)
-    return grub_errno;
+  grub_uint32_t crc32_val;
 
-  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;
 }
-- 
2.21.3