https://bugzilla.tianocore.org/show_bug.cgi?id=2522
Causes AuthService to check
IsVariablePolicyEnabled() before enforcing
write protections to allow variable deletion
when policy engine is disabled.
Only allows deletion, not modification.
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Jian J Wang <jian.j.w...@intel.com>
Cc: Chao Zhang <chao.b.zh...@intel.com>
Cc: Bret Barkelew <brbar...@microsoft.com>
Signed-off-by: Bret Barkelew <brbar...@microsoft.com>
---
SecurityPkg/Library/AuthVariableLib/AuthService.c | 22
++++++++++++++++----
SecurityPkg/Library/AuthVariableLib/AuthVariableLib.inf | 2 ++
2 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/SecurityPkg/Library/AuthVariableLib/AuthService.c
b/SecurityPkg/Library/AuthVariableLib/AuthService.c
index 2f60331f2c04..aca9a5620c28 100644
--- a/SecurityPkg/Library/AuthVariableLib/AuthService.c
+++ b/SecurityPkg/Library/AuthVariableLib/AuthService.c
@@ -19,12 +19,16 @@
to verify the signature.
Copyright (c) 2009 - 2019, Intel Corporation. All rights reserved.<BR>
+Copyright (c) Microsoft Corporation.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "AuthServiceInternal.h"
+#include <Protocol/VariablePolicy.h>
+#include <Library/VariablePolicyLib.h>
+
//
// Public Exponent of RSA Key.
//
@@ -217,9 +221,12 @@ NeedPhysicallyPresent(
IN EFI_GUID *VendorGuid
)
{
- if ((CompareGuid (VendorGuid, &gEfiSecureBootEnableDisableGuid) && (StrCmp
(VariableName, EFI_SECURE_BOOT_ENABLE_NAME) == 0))
- || (CompareGuid (VendorGuid, &gEfiCustomModeEnableGuid) && (StrCmp
(VariableName, EFI_CUSTOM_MODE_NAME) == 0))) {
- return TRUE;
+ // If the VariablePolicy engine is disabled, allow deletion of any
authenticated variables.
+ if (IsVariablePolicyEnabled()) {
+ if ((CompareGuid (VendorGuid, &gEfiSecureBootEnableDisableGuid) && (StrCmp
(VariableName, EFI_SECURE_BOOT_ENABLE_NAME) == 0))
+ || (CompareGuid (VendorGuid, &gEfiCustomModeEnableGuid) && (StrCmp
(VariableName, EFI_CUSTOM_MODE_NAME) == 0))) {
+ return TRUE;
+ }
}
return FALSE;
@@ -842,7 +849,8 @@ ProcessVariable (
&OrgVariableInfo
);
- if ((!EFI_ERROR (Status)) && IsDeleteAuthVariable
(OrgVariableInfo.Attributes, Data, DataSize, Attributes) &&
UserPhysicalPresent()) {
+ // If the VariablePolicy engine is disabled, allow deletion of any
authenticated variables.
+ if ((!EFI_ERROR (Status)) && IsDeleteAuthVariable
(OrgVariableInfo.Attributes, Data, DataSize, Attributes) &&
(UserPhysicalPresent() || !IsVariablePolicyEnabled())) {
//
// Allow the delete operation of common authenticated variable(AT or AW)
at user physical presence.
//
@@ -1960,6 +1968,12 @@ VerifyTimeBasedPayload (
CopyMem (Buffer, PayloadPtr, PayloadSize);
+ // If the VariablePolicy engine is disabled, allow deletion of any
authenticated variables.
+ if (PayloadSize == 0 && (Attributes & EFI_VARIABLE_APPEND_WRITE) == 0 &&
!IsVariablePolicyEnabled()) {
+ VerifyStatus = TRUE;
+ goto Exit;
+ }
+
if (AuthVarType == AuthVarTypePk) {
//
// Verify that the signature has been made with the current Platform Key
(no chaining for PK).
diff --git a/SecurityPkg/Library/AuthVariableLib/AuthVariableLib.inf
b/SecurityPkg/Library/AuthVariableLib/AuthVariableLib.inf
index 8d4ce14df494..8eadeebcebd7 100644
--- a/SecurityPkg/Library/AuthVariableLib/AuthVariableLib.inf
+++ b/SecurityPkg/Library/AuthVariableLib/AuthVariableLib.inf
@@ -3,6 +3,7 @@
#
# Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>
# Copyright (c) 2018, ARM Limited. All rights reserved.<BR>
+# Copyright (c) Microsoft Corporation.
#
# SPDX-License-Identifier: BSD-2-Clause-Patent
#
@@ -41,6 +42,7 @@ [LibraryClasses]
MemoryAllocationLib
BaseCryptLib
PlatformSecureLib
+ VariablePolicyLib
[Guids]
## CONSUMES ## Variable:L"SetupMode"
--
2.26.2.windows.1.8.g01c50adf56.20200515075929
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