From 688e88256f4137b23522b45727a8207983be90a1 Mon Sep 17 00:00:00 2001
From: Heinrich Schuchardt <xypron.glpk@gmx.de>
Date: Sat, 23 Jan 2021 19:33:11 +0100
Subject: [PATCH] efi_loader: correct block IO alignment check
If the field Media->IoAlign of the EFI block IO protocol is zero, no
alignment is required. Our code required 4 GiB alignment in this case.
Don't check buffer alignment if Media->IoAlign == 0.
Fixes: f59f0825e8b9 ("efi_loader: parameter checks BLOCK_IO_PROTOCOL")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
lib/efi_loader/efi_disk.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
index c0804effde..d0aad0252a 100644
--- a/lib/efi_loader/efi_disk.c
+++ b/lib/efi_loader/efi_disk.c
@@ -142,8 +142,9 @@ static efi_status_t EFIAPI efi_disk_read_blocks(struct efi_block_io *this,
return EFI_MEDIA_CHANGED;
if (!this->media->media_present)
return EFI_NO_MEDIA;
- /* media->io_align is a power of 2 */
- if ((uintptr_t)buffer & (this->media->io_align - 1))
+ /* media->io_align is a power of 2 or 0 */
+ if (this->media->io_align &&
+ (uintptr_t)buffer & (this->media->io_align - 1))
return EFI_INVALID_PARAMETER;
if (lba * this->media->block_size + buffer_size >
this->media->last_block * this->media->block_size)
@@ -209,8 +210,9 @@ static efi_status_t EFIAPI efi_disk_write_blocks(struct efi_block_io *this,
return EFI_MEDIA_CHANGED;
if (!this->media->media_present)
return EFI_NO_MEDIA;
- /* media->io_align is a power of 2 */
- if ((uintptr_t)buffer & (this->media->io_align - 1))
+ /* media->io_align is a power of 2 or 0 */
+ if (this->media->io_align &&
+ (uintptr_t)buffer & (this->media->io_align - 1))
return EFI_INVALID_PARAMETER;
if (lba * this->media->block_size + buffer_size >
this->media->last_block * this->media->block_size)
--
2.39.5