[PATCH v2] efi_loader: Improve the parameter check for QueryVariableInfo()

[Masami Hiramatsu]

Improve efi_query_variable_info() to check the parameter settings and
return correct error code according to the UEFI Specification 2.9,
and the Self Certification Test (SCT) II Case Specification, June
2017, chapter 4.1.4 QueryVariableInfo().

Signed-off-by: Masami Hiramatsu <masami.hiramatsu at linaro.org>
Reported-by: Kazuhiko Sakamoto <sakamoto.kazuhiko at socionext.com>
---
  Changes in v2:
   - Add a reference to SCT 2 spec.
   - Fix checkpatch.pl warnings.
   - Simplify the check according to Henrich's comments.
---
 lib/efi_loader/efi_var_common.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/lib/efi_loader/efi_var_common.c b/lib/efi_loader/efi_var_common.c
index 83479dd142..3d92afe2eb 100644
--- a/lib/efi_loader/efi_var_common.c
+++ b/lib/efi_loader/efi_var_common.c
@@ -163,6 +163,19 @@ efi_status_t EFIAPI efi_query_variable_info(
 	EFI_ENTRY("%x %p %p %p", attributes, maximum_variable_storage_size,
 		  remaining_variable_storage_size, maximum_variable_size);
 
+	if (!maximum_variable_storage_size ||
+	    !remaining_variable_storage_size ||
+	    !maximum_variable_size ||
+	    !(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS))
+		return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+	if ((attributes & ~(u32)EFI_VARIABLE_MASK) ||
+	    (attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) ||
+	    (attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) ||
+	    (!IS_ENABLED(CONFIG_EFI_SECURE_BOOT) &&
+	     (attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)))
+		return EFI_EXIT(EFI_UNSUPPORTED);
+
 	ret = efi_query_variable_info_int(attributes,
 					  maximum_variable_storage_size,
 					  remaining_variable_storage_size,