Commit 4a2ebb08 authored by Kees Cook's avatar Kees Cook Committed by Ard Biesheuvel
Browse files

efi: Replace efi_memory_attributes_table_t 0-sized array with flexible array 



While efi_memory_attributes_table_t::entry isn't used directly as an
array, it is used as a base for pointer arithmetic. The type is wrong
as it's not technically an array of efi_memory_desc_t's; they could be
larger. Regardless, leave the type unchanged and remove the old style
"0" array size. Additionally replace the open-coded entry offset code
with the existing efi_memdesc_ptr() helper.

Signed-off-by: default avatarKees Cook <kees@kernel.org>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent 887c4cf5

drivers/firmware/efi/memattr.c

+1 −1
Original line number Diff line number Diff line
@@ -164,7 +164,7 @@ int __init efi_memattr_apply_permissions(struct mm_struct *mm, 
		bool valid;

		char buf[64];



		valid = entry_is_valid((void *)tbl->entry + i * tbl->desc_size,

		valid = entry_is_valid(efi_memdesc_ptr(tbl->entry, tbl->desc_size, i),

				       &md);

		size = md.num_pages << EFI_PAGE_SHIFT;

		if (efi_enabled(EFI_DBG) || !valid)

include/linux/efi.h

+5 −1
Original line number Diff line number Diff line
@@ -608,7 +608,11 @@ typedef struct { 
	u32 num_entries;

	u32 desc_size;

	u32 flags;

	efi_memory_desc_t entry[0];

	/*

	 * There are @num_entries following, each of size @desc_size bytes,

	 * including an efi_memory_desc_t header. See efi_memdesc_ptr().

	 */

	efi_memory_desc_t entry[];

} efi_memory_attributes_table_t;



typedef struct {