0029-gpt-use-inline-functions-for-checking-status-bits.patch

From 7f6fb19999b3b825a9c04cee20c8c1dee1590813 Mon Sep 17 00:00:00 2001
From: Michael Marineau <michael.marineau@coreos.com>
Date: Tue, 20 Sep 2016 12:43:01 -0700
Subject: [PATCH] gpt: use inline functions for checking status bits

This should prevent bugs like 6078f836 and 4268f3da.
---
 grub-core/commands/gptprio.c   |  2 +-
 grub-core/commands/gptrepair.c |  6 +++---
 grub-core/lib/gpt.c            |  9 +++++++--
 include/grub/gpt_partition.h   | 35 +++++++++++++++++++++++++++-------
 4 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/grub-core/commands/gptprio.c b/grub-core/commands/gptprio.c
index eebca7a..59bc4fd 100644
--- a/grub-core/commands/gptprio.c
+++ b/grub-core/commands/gptprio.c
@@ -91,7 +91,7 @@ grub_find_next (const char *disk_name,
   if (!gpt)
     goto done;
 
-  if ((gpt->status & GRUB_GPT_BOTH_VALID) != GRUB_GPT_BOTH_VALID)
+  if (!grub_gpt_both_valid(gpt))
     if (grub_gpt_repair (dev->disk, gpt))
       goto done;
 
diff --git a/grub-core/commands/gptrepair.c b/grub-core/commands/gptrepair.c
index 66ac3f7..c17c734 100644
--- a/grub-core/commands/gptrepair.c
+++ b/grub-core/commands/gptrepair.c
@@ -65,16 +65,16 @@ grub_cmd_gptrepair (grub_command_t cmd __attribute__ ((unused)),
   if (!gpt)
     goto done;
 
-  if ((gpt->status & GRUB_GPT_BOTH_VALID) == GRUB_GPT_BOTH_VALID)
+  if (grub_gpt_both_valid (gpt))
     {
       grub_printf_ (N_("GPT already valid, %s unmodified.\n"), dev_name);
       goto done;
     }
 
-  if ((gpt->status & GRUB_GPT_PRIMARY_VALID) != GRUB_GPT_PRIMARY_VALID)
+  if (!grub_gpt_primary_valid (gpt))
     grub_printf_ (N_("Found invalid primary GPT on %s\n"), dev_name);
 
-  if ((gpt->status & GRUB_GPT_BACKUP_VALID) != GRUB_GPT_BACKUP_VALID)
+  if (!grub_gpt_backup_valid (gpt))
     grub_printf_ (N_("Found invalid backup GPT on %s\n"), dev_name);
 
   if (grub_gpt_repair (dev->disk, gpt))
diff --git a/grub-core/lib/gpt.c b/grub-core/lib/gpt.c
index 2550ed8..3e077c4 100644
--- a/grub-core/lib/gpt.c
+++ b/grub-core/lib/gpt.c
@@ -638,10 +638,15 @@ grub_gpt_repair (grub_disk_t disk, grub_gpt_t gpt)
   if (grub_gpt_check_primary (gpt))
     return grub_error (GRUB_ERR_BUG, "Generated invalid GPT primary header");
 
+  gpt->status |= (GRUB_GPT_PRIMARY_HEADER_VALID |
+		  GRUB_GPT_PRIMARY_ENTRIES_VALID);
+
   if (grub_gpt_check_backup (gpt))
     return grub_error (GRUB_ERR_BUG, "Generated invalid GPT backup header");
 
-  gpt->status |= GRUB_GPT_BOTH_VALID;
+  gpt->status |= (GRUB_GPT_BACKUP_HEADER_VALID |
+		  GRUB_GPT_BACKUP_ENTRIES_VALID);
+
   grub_dprintf ("gpt", "repairing GPT for %s successful\n", disk->name);
 
   return GRUB_ERR_NONE;
@@ -703,7 +708,7 @@ grub_gpt_write (grub_disk_t disk, grub_gpt_t gpt)
 {
   /* TODO: update/repair protective MBRs too.  */
 
-  if ((gpt->status & GRUB_GPT_BOTH_VALID) != GRUB_GPT_BOTH_VALID)
+  if (!grub_gpt_both_valid (gpt))
     return grub_error (GRUB_ERR_BAD_PART_TABLE, "Invalid GPT data");
 
   grub_dprintf ("gpt", "writing primary GPT to %s\n", disk->name);
diff --git a/include/grub/gpt_partition.h b/include/grub/gpt_partition.h
index 1a215f8..b7fbb7a 100644
--- a/include/grub/gpt_partition.h
+++ b/include/grub/gpt_partition.h
@@ -161,13 +161,6 @@ typedef enum grub_gpt_status
     GRUB_GPT_BACKUP_ENTRIES_VALID   = 0x20,
   } grub_gpt_status_t;
 
-#define GRUB_GPT_MBR_VALID (GRUB_GPT_PROTECTIVE_MBR|GRUB_GPT_HYBRID_MBR)
-#define GRUB_GPT_PRIMARY_VALID \
-  (GRUB_GPT_PRIMARY_HEADER_VALID|GRUB_GPT_PRIMARY_ENTRIES_VALID)
-#define GRUB_GPT_BACKUP_VALID \
-  (GRUB_GPT_BACKUP_HEADER_VALID|GRUB_GPT_BACKUP_ENTRIES_VALID)
-#define GRUB_GPT_BOTH_VALID (GRUB_GPT_PRIMARY_VALID|GRUB_GPT_BACKUP_VALID)
-
 /* UEFI requires the entries table to be at least 16384 bytes for a
  * total of 128 entries given the standard 128 byte entry size.  */
 #define GRUB_GPT_DEFAULT_ENTRIES_SIZE	16384
@@ -197,6 +190,34 @@ struct grub_gpt
 };
 typedef struct grub_gpt *grub_gpt_t;
 
+/* Helpers for checking the gpt status field.  */
+static inline int
+grub_gpt_mbr_valid (grub_gpt_t gpt)
+{
+  return ((gpt->status & GRUB_GPT_PROTECTIVE_MBR) ||
+	  (gpt->status & GRUB_GPT_HYBRID_MBR));
+}
+
+static inline int
+grub_gpt_primary_valid (grub_gpt_t gpt)
+{
+  return ((gpt->status & GRUB_GPT_PRIMARY_HEADER_VALID) &&
+	  (gpt->status & GRUB_GPT_PRIMARY_ENTRIES_VALID));
+}
+
+static inline int
+grub_gpt_backup_valid (grub_gpt_t gpt)
+{
+  return ((gpt->status & GRUB_GPT_BACKUP_HEADER_VALID) &&
+	  (gpt->status & GRUB_GPT_BACKUP_ENTRIES_VALID));
+}
+
+static inline int
+grub_gpt_both_valid (grub_gpt_t gpt)
+{
+  return grub_gpt_primary_valid (gpt) && grub_gpt_backup_valid (gpt);
+}
+
 /* Translate GPT sectors to GRUB's 512 byte block addresses.  */
 static inline grub_disk_addr_t
 grub_gpt_sector_to_addr (grub_gpt_t gpt, grub_uint64_t sector)
-- 
2.21.3