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>

diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
index c0804ef..d0aad02 100644 (file)
--- 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)