libblkid: fix EFI GPT uuid byte order

Intel uses little-endians for UUID, the rest of the sane world uses 16
byte big-endian array...

Reported-by: Andrew Lutomirski <luto@mit.edu>
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/shlibs/blkid/src/partitions/gpt.c b/shlibs/blkid/src/partitions/gpt.c
index 8259c2fddd2763dc461ac6884f731a1024e7a84c..7df17bb1e04cd1ef221975a9d64b2e1d7b4ff534 100644 (file)
--- a/shlibs/blkid/src/partitions/gpt.c
+++ b/shlibs/blkid/src/partitions/gpt.c
@@ -32,20 +32,18 @@ typedef uint16_t efi_char16_t;
 
 /* UUID */
 typedef struct {
-       uint8_t  b[16];
+       uint32_t time_low;
+       uint16_t time_mid;
+       uint16_t time_hi_and_version;
+       uint8_t clock_seq_hi;
+       uint8_t clock_seq_low;
+       uint8_t node[6];
 } efi_guid_t;
 
-#define EFI_GUID(a,b,c,d0,d1,d2,d3,d4,d5,d6,d7)  ((efi_guid_t) \
-               {{ \
-       (a) & 0xff, ((a) >> 8) & 0xff, ((a) >> 16) & 0xff, ((a) >> 24) & 0xff, \
-       (b) & 0xff, ((b) >> 8) & 0xff, \
-       (c) & 0xff, ((c) >> 8) & 0xff, \
-       (d0), (d1), (d2), (d3), (d4), (d5), (d6), (d7) \
-}})
-
-#define GPT_UNUSED_ENTRY_GUID  EFI_GUID(0x00000000, 0x0000, 0x0000, 0x00, 0x00, \
-                                       0x00, 0x00, 0x00, 0x00, 0x00, 0x00)
 
+#define GPT_UNUSED_ENTRY_GUID \
+           ((efi_guid_t) { 0x00000000, 0x0000, 0x0000, 0x00, 0x00, \
+                           { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }})
 struct gpt_header {
        uint64_t        signature;              /* "EFI PART" */
        uint32_t        revision;
@@ -120,6 +118,17 @@ static inline int guidcmp(efi_guid_t left, efi_guid_t right)
        return memcmp(&left, &right, sizeof (efi_guid_t));
 }
 
+/*
+ * UUID is traditionaly 16 byte big-endian array, except Intel EFI
+ * specification where the UUID is a structure of little-endian fields.
+ */
+static void swap_efi_guid(efi_guid_t *uid)
+{
+       uid->time_low = swab32(uid->time_low);
+       uid->time_mid = swab16(uid->time_mid);
+       uid->time_hi_and_version = swab16(uid->time_hi_and_version);
+}
+
 static int last_lba(blkid_probe pr, uint64_t *lba)
 {
        blkid_loff_t sz = blkid_probe_get_size(pr);
@@ -352,6 +361,9 @@ static int probe_gpt_pt(blkid_probe pr, const struct blkid_idmag *mag)
                        (unsigned char *) e->partition_name,
                        sizeof(e->partition_name), BLKID_ENC_UTF16LE);
 
+               swap_efi_guid(&e->unique_partition_guid);
+               swap_efi_guid(&e->partition_type_guid);
+
                blkid_partition_set_uuid(par,
                        (const unsigned char *) &e->unique_partition_guid);