From 4a2ebb082297f41803742729642961532e54079e Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 11 Jul 2024 10:11:13 -0700 Subject: [PATCH] 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: Kees Cook Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/memattr.c | 2 +- include/linux/efi.h | 6 +++++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/memattr.c b/drivers/firmware/efi/memattr.c index ab85bf8e165a..164203429fa7 100644 --- a/drivers/firmware/efi/memattr.c +++ b/drivers/firmware/efi/memattr.c @@ -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) diff --git a/include/linux/efi.h b/include/linux/efi.h index 67b2fa80c8b9..6bf3c4fe8511 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -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 {