From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Lukasz Hawrylko <lukasz.hawrylko@linux.intel.com>
Date: Mon, 16 Dec 2019 11:15:55 +0100
Subject: [PATCH] multiboot2: Set min address for mbi allocation to 0x1000
In some cases GRUB2 allocates multiboot2 structure at 0 address, that is
a confusing behavior. Consumers of that structure can have internal NULL-checks
that will throw an error when get a pointer to data allocated at address 0.
To prevent that, define min address for mbi allocation on x86 and x86_64
platforms.
Signed-off-by: Lukasz Hawrylko <lukasz.hawrylko@linux.intel.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Upstream-commit-id: 0f3f5b7c13f
---
grub-core/loader/multiboot_mbi2.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/grub-core/loader/multiboot_mbi2.c b/grub-core/loader/multiboot_mbi2.c
index 47d4c6f0977..797870b6138 100644
--- a/grub-core/loader/multiboot_mbi2.c
+++ b/grub-core/loader/multiboot_mbi2.c
@@ -49,6 +49,12 @@
#define HAS_VGA_TEXT 0
#endif
+#if defined (__i386__) || defined (__x86_64__)
+#define MBI_MIN_ADDR 0x1000
+#else
+#define MBI_MIN_ADDR 0
+#endif
+
struct module
{
struct module *next;
@@ -747,7 +753,7 @@ grub_multiboot2_make_mbi (grub_uint32_t *target)
COMPILE_TIME_ASSERT (MULTIBOOT_TAG_ALIGN % sizeof (grub_properly_aligned_t) == 0);
err = grub_relocator_alloc_chunk_align (grub_multiboot2_relocator, &ch,
- 0, 0xffffffff - bufsize,
+ MBI_MIN_ADDR, 0xffffffff - bufsize,
bufsize, MULTIBOOT_TAG_ALIGN,
GRUB_RELOCATOR_PREFERENCE_NONE, 1);
if (err)