efi_loader: GetVariable set attributes for EFI_BUFFER_TOO_SMALL

UEFI spec 2.7 erratum A leaves it undefined if Attributes should be set if
GetVariable() returns EFI_BUFFER_TOO_SMALL.

UEFI spec 2.8 defines that Attributes should be set if the return value is
either EFI_SUCCESS or EFI_BUFFER_TOO_SMALL.

Set Attributes if the return value is EFI_BUFFER_TOO_SMALL.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 37728c3..28b1aa7 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -202,8 +202,10 @@
 		len /= 2;
 		*data_size = len;
 
-		if (in_size < len)
-			return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
+		if (in_size < len) {
+			ret = EFI_BUFFER_TOO_SMALL;
+			goto out;
+		}
 
 		if (!data)
 			return EFI_EXIT(EFI_INVALID_PARAMETER);
@@ -217,8 +219,10 @@
 
 		*data_size = len;
 
-		if (in_size < len)
-			return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
+		if (in_size < len) {
+			ret = EFI_BUFFER_TOO_SMALL;
+			goto out;
+		}
 
 		if (!data)
 			return EFI_EXIT(EFI_INVALID_PARAMETER);
@@ -232,10 +236,11 @@
 		return EFI_EXIT(EFI_DEVICE_ERROR);
 	}
 
+out:
 	if (attributes)
 		*attributes = attr & EFI_VARIABLE_MASK;
 
-	return EFI_EXIT(EFI_SUCCESS);
+	return EFI_EXIT(ret);
 }
 
 static char *efi_variables_list;