[PATCH] gpt: don't malfunction on big-endian systems

[Jim Meyering]

Numerous GPT tests would fail when run on e.g., big-endian PPC.
* libparted/labels/gpt.c (gpt_read): Now that we use the
SizeOfPartitionEntry member, be sure to convert from GPT's
little-endian on-disk format to to CPU endianness.
This bug was introduced via commit 14cce9b2, 2009-06-10, "gpt:
fix gpt_read to read all of the partition entries correctly".
* libparted/labels/gpt.c (_header_is_valid): Also convert it here.
Add a test to ensure that the partition entry size is no larger
than the slightly arbitrary UINT32_MAX/16.
* NEWS (Bug fixes): Mention it.
---
 NEWS                   |    3 +++
 libparted/labels/gpt.c |   12 +++++++-----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/NEWS b/NEWS
index 04741a2..d4147ad 100644
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,9 @@ GNU parted NEWS                                    -*- outline -*-

 ** Bug fixes

+  big-endian systems can once again read GPT partition tables
+  [bug introduced in parted-1.9.0]
+
   ped_partition_is_busy no longer calls libparted's exception handler,
   since doing so caused trouble with anaconda/pyparted when operating on
   dmraid devices.
diff --git a/libparted/labels/gpt.c b/libparted/labels/gpt.c
index cc9bcdc..b4549ef 100644
--- a/libparted/labels/gpt.c
+++ b/libparted/labels/gpt.c
@@ -608,8 +608,10 @@ _header_is_valid (const PedDevice* dev, GuidPartitionTableHeader_t* gpt)
 	 * the SizeOfPartitionEntry must be a multiple of 8 and
 	 * no smaller than the size of the PartitionEntry structure.
 	 */
-	uint32_t sope = gpt->SizeOfPartitionEntry;
-	if (sope % 8 != 0 || sope < sizeof(GuidPartitionEntry_t) )
+	uint32_t sope = PED_LE32_TO_CPU (gpt->SizeOfPartitionEntry);
+	if (sope % 8 != 0
+            || sope < sizeof (GuidPartitionEntry_t)
+            || (UINT32_MAX >> 4) < sope)
 		return 0;

 	origcrc = gpt->HeaderCRC32;
@@ -911,7 +913,8 @@ gpt_read (PedDisk * disk)
 	if (!_parse_header (disk, gpt, &write_back))
 		goto error_free_gpt;

-	ptes_sectors = ped_div_round_up (gpt->SizeOfPartitionEntry
+	uint32_t p_ent_size = PED_LE32_TO_CPU (gpt->SizeOfPartitionEntry);
+	ptes_sectors = ped_div_round_up (p_ent_size
 					 * gpt_disk_data->entry_count,
 					 disk->dev->sector_size);

@@ -926,8 +929,7 @@ gpt_read (PedDisk * disk)

 	for (i = 0; i < gpt_disk_data->entry_count; i++) {
 		GuidPartitionEntry_t* pte
-		  = (GuidPartitionEntry_t*) ((char *)ptes + i
-					     * gpt->SizeOfPartitionEntry);
+		  = (GuidPartitionEntry_t*) ((char *)ptes + i * p_ent_size);
 		PedPartition* part;
 		PedConstraint* constraint_exact;

--
1.6.5.rc2.204.g8ea19