From 0f3f5b7c13fa9b677a64cf11f20eca0f850a2b20 Mon Sep 17 00:00:00 2001 From: Lukasz Hawrylko 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 Reviewed-by: Daniel Kiper --- 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 53da78615..18e766c7b 100644 --- a/grub-core/loader/multiboot_mbi2.c +++ b/grub-core/loader/multiboot_mbi2.c @@ -48,6 +48,12 @@ #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; @@ -708,7 +714,7 @@ 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)