0022-gpt-properly-detect-and-repair-invalid-tables.patch

From 29d1ef938cc64d87b09955645b46f947bfcf7b60 Mon Sep 17 00:00:00 2001
From: Michael Marineau <michael.marineau@coreos.com>
Date: Sat, 20 Aug 2016 17:42:12 -0700
Subject: [PATCH] gpt: properly detect and repair invalid tables

GPT_BOTH_VALID is 4 bits so simple a boolean check is not sufficient.
This broken condition allowed gptprio to trust bogus disk locations in
headers that were marked invalid causing arbitrary disk corruption.
---
 grub-core/commands/gptprio.c | 2 +-
 grub-core/lib/gpt.c          | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/grub-core/commands/gptprio.c b/grub-core/commands/gptprio.c
index 2415747..2021cb2 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))
+  if ((gpt->status & GRUB_GPT_BOTH_VALID) != GRUB_GPT_BOTH_VALID)
     if (grub_gpt_repair (dev->disk, gpt))
       goto done;
 
diff --git a/grub-core/lib/gpt.c b/grub-core/lib/gpt.c
index b744991..0daf3f8 100644
--- a/grub-core/lib/gpt.c
+++ b/grub-core/lib/gpt.c
@@ -648,7 +648,7 @@ grub_gpt_write (grub_disk_t disk, grub_gpt_t gpt)
 {
   /* TODO: update/repair protective MBRs too.  */
 
-  if (!(gpt->status & GRUB_GPT_BOTH_VALID))
+  if ((gpt->status & GRUB_GPT_BOTH_VALID) != GRUB_GPT_BOTH_VALID)
     return grub_error (GRUB_ERR_BAD_PART_TABLE, "Invalid GPT data");
 
   grub_dprintf ("gpt", "writing primary GPT to %s\n", disk->name);
-- 
2.21.3