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* [Patch v2 1/1] MdeModulePkg/Variable/RuntimeDxe: Restore Variable Lock Protocol behavior
@ 2020-12-09 18:06 Michael D Kinney
  2020-12-10  2:24 ` [edk2-devel] " Wu, Hao A
  0 siblings, 1 reply; 8+ messages in thread
From: Michael D Kinney @ 2020-12-09 18:06 UTC (permalink / raw)
  To: devel; +Cc: Bret Barkelew, Hao A Wu, Liming Gao, Bret Barkelew

From: Bret Barkelew <bret.barkelew@microsoft.com>

https://bugzilla.tianocore.org/show_bug.cgi?id=3111

The VariableLock shim currently fails if called twice because the
underlying Variable Policy engine returns an error if a policy is set
on an existing variable.

This breaks existing code which expect it to silently pass if a variable
is locked multiple times (because it should "be locked").

Refactor the shim to confirm that the variable is indeed locked and then
change the error to EFI_SUCCESS and generate a DEBUG_ERROR message so
the duplicate lock can be reported in a debug log and removed.

Add host based unit tests for the multiple lock case using Variable Lock
Protocol, Variable Policy Protocol, and mixes of Variable Lock Protocol
and Variable Policy Protocol.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Bret Barkelew <Bret.Barkelew@microsoft.com>
---
 MdeModulePkg/Test/MdeModulePkgHostTest.dsc    |  11 +
 .../VariableLockRequestToLockUnitTest.c       | 434 ++++++++++++++++++
 .../VariableLockRequestToLockUnitTest.inf     |  36 ++
 .../RuntimeDxe/VariableLockRequestToLock.c    | 363 +++++++++++++--
 4 files changed, 809 insertions(+), 35 deletions(-)
 create mode 100644 MdeModulePkg/Universal/Variable/RuntimeDxe/RuntimeDxeUnitTest/VariableLockRequestToLockUnitTest.c
 create mode 100644 MdeModulePkg/Universal/Variable/RuntimeDxe/RuntimeDxeUnitTest/VariableLockRequestToLockUnitTest.inf

diff --git a/MdeModulePkg/Test/MdeModulePkgHostTest.dsc b/MdeModulePkg/Test/MdeModulePkgHostTest.dsc
index 72a119db4568..4da4692c8451 100644
--- a/MdeModulePkg/Test/MdeModulePkgHostTest.dsc
+++ b/MdeModulePkg/Test/MdeModulePkgHostTest.dsc
@@ -19,6 +19,9 @@ [Defines]
 
 !include UnitTestFrameworkPkg/UnitTestFrameworkPkgHost.dsc.inc
 
+[LibraryClasses]
+  SafeIntLib|MdePkg/Library/BaseSafeIntLib/BaseSafeIntLib.inf
+
 [Components]
   MdeModulePkg/Library/DxeResetSystemLib/UnitTest/MockUefiRuntimeServicesTableLib.inf
 
@@ -30,3 +33,11 @@ [Components]
       ResetSystemLib|MdeModulePkg/Library/DxeResetSystemLib/DxeResetSystemLib.inf
       UefiRuntimeServicesTableLib|MdeModulePkg/Library/DxeResetSystemLib/UnitTest/MockUefiRuntimeServicesTableLib.inf
   }
+
+  MdeModulePkg/Universal/Variable/RuntimeDxe/RuntimeDxeUnitTest/VariableLockRequestToLockUnitTest.inf {
+    <LibraryClasses>
+      VariablePolicyLib|MdeModulePkg/Library/VariablePolicyLib/VariablePolicyLib.inf
+      VariablePolicyHelperLib|MdeModulePkg/Library/VariablePolicyHelperLib/VariablePolicyHelperLib.inf
+    <PcdsFixedAtBuild>
+      gEfiMdeModulePkgTokenSpaceGuid.PcdAllowVariablePolicyEnforcementDisable|TRUE
+  }
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/RuntimeDxeUnitTest/VariableLockRequestToLockUnitTest.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/RuntimeDxeUnitTest/VariableLockRequestToLockUnitTest.c
new file mode 100644
index 000000000000..2f4c4d2f79f4
--- /dev/null
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/RuntimeDxeUnitTest/VariableLockRequestToLockUnitTest.c
@@ -0,0 +1,434 @@
+/** @file
+  This is a host-based unit test for the VariableLockRequestToLock shim.
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <stdio.h>
+#include <string.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <cmocka.h>
+
+#include <Uefi.h>
+#include <Library/DebugLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/MemoryAllocationLib.h>
+#include <Library/UnitTestLib.h>
+#include <Library/VariablePolicyLib.h>
+#include <Library/VariablePolicyHelperLib.h>
+
+#include <Protocol/VariableLock.h>
+
+#define UNIT_TEST_NAME        "VarPol/VarLock Shim Unit Test"
+#define UNIT_TEST_VERSION     "1.0"
+
+///=== CODE UNDER TEST ===========================================================================
+
+EFI_STATUS
+EFIAPI
+VariableLockRequestToLock (
+  IN CONST EDKII_VARIABLE_LOCK_PROTOCOL  *This,
+  IN       CHAR16                        *VariableName,
+  IN       EFI_GUID                      *VendorGuid
+  );
+
+///=== TEST DATA ==================================================================================
+
+//
+// Test GUID 1 {F955BA2D-4A2C-480C-BFD1-3CC522610592}
+//
+EFI_GUID  mTestGuid1 = {
+  0xf955ba2d, 0x4a2c, 0x480c, {0xbf, 0xd1, 0x3c, 0xc5, 0x22, 0x61, 0x5, 0x92}
+};
+
+//
+// Test GUID 2 {2DEA799E-5E73-43B9-870E-C945CE82AF3A}
+//
+EFI_GUID  mTestGuid2 = {
+  0x2dea799e, 0x5e73, 0x43b9, {0x87, 0xe, 0xc9, 0x45, 0xce, 0x82, 0xaf, 0x3a}
+};
+
+//
+// Test GUID 3 {698A2BFD-A616-482D-B88C-7100BD6682A9}
+//
+EFI_GUID  mTestGuid3 = {
+  0x698a2bfd, 0xa616, 0x482d, {0xb8, 0x8c, 0x71, 0x0, 0xbd, 0x66, 0x82, 0xa9}
+};
+
+#define TEST_VAR_1_NAME              L"TestVar1"
+#define TEST_VAR_2_NAME              L"TestVar2"
+#define TEST_VAR_3_NAME              L"TestVar3"
+
+#define TEST_POLICY_ATTRIBUTES_NULL  0
+#define TEST_POLICY_MIN_SIZE_NULL    0
+#define TEST_POLICY_MAX_SIZE_NULL    MAX_UINT32
+
+#define TEST_POLICY_MIN_SIZE_10      10
+#define TEST_POLICY_MAX_SIZE_200     200
+
+///=== HELPER FUNCTIONS ===========================================================================
+
+/**
+  Mocked version of GetVariable, for testing.
+
+  @param  VariableName
+  @param  VendorGuid
+  @param  Attributes
+  @param  DataSize
+  @param  Data
+**/
+EFI_STATUS
+EFIAPI
+StubGetVariableNull (
+  IN     CHAR16    *VariableName,
+  IN     EFI_GUID  *VendorGuid,
+  OUT    UINT32    *Attributes,  OPTIONAL
+  IN OUT UINTN     *DataSize,
+  OUT    VOID      *Data         OPTIONAL
+  )
+{
+  UINT32      MockedAttr;
+  UINTN       MockedDataSize;
+  VOID        *MockedData;
+  EFI_STATUS  MockedReturn;
+
+  check_expected_ptr (VariableName);
+  check_expected_ptr (VendorGuid);
+  check_expected_ptr (DataSize);
+
+  MockedAttr     = (UINT32)mock();
+  MockedDataSize = (UINTN)mock();
+  MockedData     = (VOID*)(UINTN)mock();
+  MockedReturn   = (EFI_STATUS)mock();
+
+  if (Attributes != NULL) {
+    *Attributes = MockedAttr;
+  }
+  if (Data != NULL && !EFI_ERROR (MockedReturn)) {
+    CopyMem (Data, MockedData, MockedDataSize);
+  }
+
+  *DataSize = MockedDataSize;
+
+  return MockedReturn;
+}
+
+//
+// Anything you think might be helpful that isn't a test itself.
+//
+
+/**
+  This is a common setup function that will ensure the library is always
+  initialized with the stubbed GetVariable.
+
+  Not used by all test cases, but by most.
+
+  @param[in]  Context  Unit test case context
+**/
+STATIC
+UNIT_TEST_STATUS
+EFIAPI
+LibInitMocked (
+  IN UNIT_TEST_CONTEXT  Context
+  )
+{
+  return EFI_ERROR (InitVariablePolicyLib (StubGetVariableNull)) ? UNIT_TEST_ERROR_PREREQUISITE_NOT_MET : UNIT_TEST_PASSED;
+}
+
+/**
+  Common cleanup function to make sure that the library is always de-initialized
+  prior to the next test case.
+
+  @param[in]  Context  Unit test case context
+**/
+STATIC
+VOID
+EFIAPI
+LibCleanup (
+  IN UNIT_TEST_CONTEXT  Context
+  )
+{
+  DeinitVariablePolicyLib();
+}
+
+///=== TEST CASES =================================================================================
+
+///===== SHIM SUITE ===========================================================
+
+/**
+  Test Case that locks a single variable using the Variable Lock Protocol.
+  The call is expected to succeed.
+
+  @param[in]  Context  Unit test case context
+**/
+UNIT_TEST_STATUS
+EFIAPI
+LockingWithoutAnyPoliciesShouldSucceed (
+  IN UNIT_TEST_CONTEXT  Context
+  )
+{
+  EFI_STATUS  Status;
+
+  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME, &mTestGuid1);
+  UT_ASSERT_NOT_EFI_ERROR (Status);
+
+  return UNIT_TEST_PASSED;
+}
+
+/**
+  Test Case that locks the same variable twice using the Variable Lock Procol.
+  Both calls are expected to succeed.
+
+  @param[in]  Context  Unit test case context
+  **/
+UNIT_TEST_STATUS
+EFIAPI
+LockingTwiceShouldSucceed (
+  IN UNIT_TEST_CONTEXT  Context
+  )
+{
+  EFI_STATUS  Status;
+
+  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME, &mTestGuid1);
+  UT_ASSERT_NOT_EFI_ERROR (Status);
+
+  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME, &mTestGuid1);
+  UT_ASSERT_NOT_EFI_ERROR (Status);
+
+  return UNIT_TEST_PASSED;
+}
+
+/**
+  Test Case that locks a variable using the Variable Policy Protocol then locks
+  the same variable using the Variable Lock Protocol.
+  Both calls are expected to succeed.
+
+  @param[in]  Context  Unit test case context
+  **/
+UNIT_TEST_STATUS
+EFIAPI
+LockingALockedVariableShouldSucceed (
+  IN UNIT_TEST_CONTEXT  Context
+  )
+{
+  EFI_STATUS             Status;
+  VARIABLE_POLICY_ENTRY  *NewEntry;
+
+  //
+  // Create a variable policy that locks the variable.
+  //
+  Status = CreateBasicVariablePolicy (
+             &mTestGuid1,
+             TEST_VAR_1_NAME,
+             TEST_POLICY_MIN_SIZE_NULL,
+             TEST_POLICY_MAX_SIZE_200,
+             TEST_POLICY_ATTRIBUTES_NULL,
+             TEST_POLICY_ATTRIBUTES_NULL,
+             VARIABLE_POLICY_TYPE_LOCK_NOW,
+             &NewEntry
+             );
+  UT_ASSERT_NOT_EFI_ERROR (Status);
+
+  //
+  // Register the new policy.
+  //
+  Status = RegisterVariablePolicy (NewEntry);
+
+  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME, &mTestGuid1);
+  UT_ASSERT_NOT_EFI_ERROR (Status);
+
+  FreePool (NewEntry);
+
+  return UNIT_TEST_PASSED;
+}
+
+/**
+  Test Case that locks a variable using the Variable Policy Protocol with a
+  policy other than LOCK_NOW then attempts to lock the same variable using the
+  Variable Lock Protocol.  The call to Variable Policy is expected to succced
+  and the call to Variable Lock is expected to fail.
+
+  @param[in]  Context  Unit test case context
+  **/
+UNIT_TEST_STATUS
+EFIAPI
+LockingAnUnlockedVariableShouldFail (
+  IN UNIT_TEST_CONTEXT      Context
+  )
+{
+  EFI_STATUS                Status;
+  VARIABLE_POLICY_ENTRY     *NewEntry;
+
+  // Create a variable policy that locks the variable.
+  Status = CreateVarStateVariablePolicy (&mTestGuid1,
+                                         TEST_VAR_1_NAME,
+                                         TEST_POLICY_MIN_SIZE_NULL,
+                                         TEST_POLICY_MAX_SIZE_200,
+                                         TEST_POLICY_ATTRIBUTES_NULL,
+                                         TEST_POLICY_ATTRIBUTES_NULL,
+                                         &mTestGuid2,
+                                         1,
+                                         TEST_VAR_2_NAME,
+                                         &NewEntry);
+  UT_ASSERT_NOT_EFI_ERROR (Status);
+
+  // Register the new policy.
+  Status = RegisterVariablePolicy (NewEntry);
+
+  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME, &mTestGuid1);
+  UT_ASSERT_TRUE (EFI_ERROR (Status));
+
+  FreePool (NewEntry);
+
+  return UNIT_TEST_PASSED;
+}
+
+/**
+  Test Case that locks a variable using Variable Lock Protocol Policy Protocol
+  then and then attempts to lock the same variable using the Variable Policy
+  Protocol.  The call to Variable Lock is expected to succced and the call to
+  Variable Policy is expected to fail.
+
+  @param[in]  Context  Unit test case context
+  **/
+UNIT_TEST_STATUS
+EFIAPI
+SettingPolicyForALockedVariableShouldFail (
+  IN UNIT_TEST_CONTEXT      Context
+  )
+{
+  EFI_STATUS                Status;
+  VARIABLE_POLICY_ENTRY     *NewEntry;
+
+  // Lock the variable.
+  Status = VariableLockRequestToLock (NULL, TEST_VAR_1_NAME, &mTestGuid1);
+  UT_ASSERT_NOT_EFI_ERROR (Status);
+
+  // Create a variable policy that locks the variable.
+  Status = CreateVarStateVariablePolicy (&mTestGuid1,
+                                         TEST_VAR_1_NAME,
+                                         TEST_POLICY_MIN_SIZE_NULL,
+                                         TEST_POLICY_MAX_SIZE_200,
+                                         TEST_POLICY_ATTRIBUTES_NULL,
+                                         TEST_POLICY_ATTRIBUTES_NULL,
+                                         &mTestGuid2,
+                                         1,
+                                         TEST_VAR_2_NAME,
+                                         &NewEntry);
+  UT_ASSERT_NOT_EFI_ERROR (Status);
+
+  // Register the new policy.
+  Status = RegisterVariablePolicy (NewEntry);
+  UT_ASSERT_TRUE (EFI_ERROR (Status));
+
+  FreePool (NewEntry);
+
+  return UNIT_TEST_PASSED;
+}
+
+/**
+  Main entry point to this unit test application.
+
+  Sets up and runs the test suites.
+**/
+VOID
+EFIAPI
+UnitTestMain (
+  VOID
+  )
+{
+  EFI_STATUS                  Status;
+  UNIT_TEST_FRAMEWORK_HANDLE  Framework;
+  UNIT_TEST_SUITE_HANDLE      ShimTests;
+
+  Framework = NULL;
+
+  DEBUG ((DEBUG_INFO, "%a v%a\n", UNIT_TEST_NAME, UNIT_TEST_VERSION));
+
+  //
+  // Start setting up the test framework for running the tests.
+  //
+  Status = InitUnitTestFramework (&Framework, UNIT_TEST_NAME, gEfiCallerBaseName, UNIT_TEST_VERSION);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "Failed in InitUnitTestFramework. Status = %r\n", Status));
+    goto EXIT;
+  }
+
+  //
+  // Add all test suites and tests.
+  //
+  Status = CreateUnitTestSuite (
+             &ShimTests, Framework,
+             "Variable Lock Shim Tests", "VarPolicy.VarLockShim", NULL, NULL
+             );
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "Failed in CreateUnitTestSuite for ShimTests\n"));
+    Status = EFI_OUT_OF_RESOURCES;
+    goto EXIT;
+  }
+  AddTestCase (
+    ShimTests,
+    "Locking a variable with no matching policies should always work", "EmptyPolicies",
+    LockingWithoutAnyPoliciesShouldSucceed, LibInitMocked, LibCleanup, NULL
+    );
+  AddTestCase (
+    ShimTests,
+    "Locking a variable twice should always work", "DoubleLock",
+    LockingTwiceShouldSucceed, LibInitMocked, LibCleanup, NULL
+    );
+  AddTestCase (
+    ShimTests,
+    "Locking a variable that's already locked by another policy should work", "LockAfterPolicy",
+    LockingALockedVariableShouldSucceed, LibInitMocked, LibCleanup, NULL
+    );
+  AddTestCase (
+    ShimTests,
+    "Locking a variable that already has an unlocked policy should fail", "LockAfterUnlockedPolicy",
+    LockingAnUnlockedVariableShouldFail, LibInitMocked, LibCleanup, NULL
+    );
+  AddTestCase (
+    ShimTests,
+    "Adding a policy for a variable that has previously been locked should always fail", "SetPolicyAfterLock",
+    SettingPolicyForALockedVariableShouldFail, LibInitMocked, LibCleanup, NULL
+    );
+
+  //
+  // Execute the tests.
+  //
+  Status = RunAllTestSuites (Framework);
+
+EXIT:
+  if (Framework != NULL) {
+    FreeUnitTestFramework (Framework);
+  }
+
+  return;
+}
+
+///
+/// Avoid ECC error for function name that starts with lower case letter
+///
+#define Main main
+
+/**
+  Standard POSIX C entry point for host based unit test execution.
+
+  @param[in] Argc  Number of arguments
+  @param[in] Argv  Array of pointers to arguments
+
+  @retval 0      Success
+  @retval other  Error
+**/
+INT32
+Main (
+  IN INT32  Argc,
+  IN CHAR8  *Argv[]
+  )
+{
+  UnitTestMain ();
+  return 0;
+}
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/RuntimeDxeUnitTest/VariableLockRequestToLockUnitTest.inf b/MdeModulePkg/Universal/Variable/RuntimeDxe/RuntimeDxeUnitTest/VariableLockRequestToLockUnitTest.inf
new file mode 100644
index 000000000000..2a659d7e1370
--- /dev/null
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/RuntimeDxeUnitTest/VariableLockRequestToLockUnitTest.inf
@@ -0,0 +1,36 @@
+## @file
+# This is a host-based unit test for the VariableLockRequestToLock shim.
+#
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+##
+
+[Defines]
+  INF_VERSION         = 0x00010017
+  BASE_NAME           = VariableLockRequestToLockUnitTest
+  FILE_GUID           = A7388B6C-7274-4717-9649-BDC5DFD1FCBE
+  VERSION_STRING      = 1.0
+  MODULE_TYPE         = HOST_APPLICATION
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64 ARM AARCH64
+#
+
+[Sources]
+  VariableLockRequestToLockUnitTest.c
+  ../VariableLockRequestToLock.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+  UnitTestFrameworkPkg/UnitTestFrameworkPkg.dec
+
+[LibraryClasses]
+  UnitTestLib
+  DebugLib
+  VariablePolicyLib
+  VariablePolicyHelperLib
+  BaseMemoryLib
+  MemoryAllocationLib
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableLockRequestToLock.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableLockRequestToLock.c
index 4aa854aaf260..191de6b907c5 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableLockRequestToLock.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableLockRequestToLock.c
@@ -1,67 +1,360 @@
-/** @file -- VariableLockRequestToLock.c
-Temporary location of the RequestToLock shim code while
-projects are moved to VariablePolicy. Should be removed when deprecated.
+/** @file
+  Temporary location of the RequestToLock shim code while projects
+  are moved to VariablePolicy. Should be removed when deprecated.
 
-Copyright (c) Microsoft Corporation.
-SPDX-License-Identifier: BSD-2-Clause-Patent
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
 
 #include <Uefi.h>
-
 #include <Library/DebugLib.h>
+#include <Library/BaseMemoryLib.h>
 #include <Library/MemoryAllocationLib.h>
-
-#include <Protocol/VariableLock.h>
-
-#include <Protocol/VariablePolicy.h>
 #include <Library/VariablePolicyLib.h>
 #include <Library/VariablePolicyHelperLib.h>
+#include <Protocol/VariableLock.h>
 
+//
+// NOTE: DO NOT USE THESE MACROS on any structure that has not been validated.
+//       Current table data has already been sanitized.
+//
+#define GET_NEXT_POLICY(CurPolicy)  (VARIABLE_POLICY_ENTRY*)((UINT8*)CurPolicy + CurPolicy->Size)
+#define GET_POLICY_NAME(CurPolicy)  (CHAR16*)((UINTN)CurPolicy + CurPolicy->OffsetToName)
+
+#define MATCH_PRIORITY_EXACT  0
+#define MATCH_PRIORITY_MIN    MAX_UINT8
+
+/**
+  This helper function evaluates a policy and determines whether it matches the
+  target variable. If matched, will also return a value corresponding to the
+  priority of the match.
+
+  The rules for "best match" are listed in the Variable Policy Spec.
+  Perfect name matches will return 0.
+  Single wildcard characters will return the number of wildcard characters.
+  Full namespaces will return MAX_UINT8.
+
+  @param[in]  EvalEntry      Pointer to the policy entry being evaluated.
+  @param[in]  VariableName   Same as EFI_SET_VARIABLE.
+  @param[in]  VendorGuid     Same as EFI_SET_VARIABLE.
+  @param[out] MatchPriority  [Optional] On finding a match, this value contains
+                             the priority of the match. Lower number == higher
+                             priority. Only valid if a match found.
+
+  @retval  TRUE   Current entry matches the target variable.
+  @retval  FALSE  Current entry does not match at all.
+
+**/
+STATIC
+BOOLEAN
+EvaluatePolicyMatch (
+  IN CONST VARIABLE_POLICY_ENTRY  *EvalEntry,
+  IN CONST CHAR16                 *VariableName,
+  IN CONST EFI_GUID               *VendorGuid,
+  OUT UINT8                       *MatchPriority  OPTIONAL
+  )
+{
+  BOOLEAN  Result;
+  CHAR16   *PolicyName;
+  UINT8    CalculatedPriority;
+  UINTN    Index;
+
+  Result = FALSE;
+  CalculatedPriority = MATCH_PRIORITY_EXACT;
+
+  //
+  // Step 1: If the GUID doesn't match, we're done. No need to evaluate anything else.
+  //
+  if (!CompareGuid (&EvalEntry->Namespace, VendorGuid)) {
+    goto Exit;
+  }
+
+  //
+  // If the GUID matches, check to see whether there is a Name associated
+  // with the policy. If not, this policy matches the entire namespace.
+  // Missing Name is indicated by size being equal to name.
+  //
+  if (EvalEntry->Size == EvalEntry->OffsetToName) {
+    CalculatedPriority = MATCH_PRIORITY_MIN;
+    Result = TRUE;
+    goto Exit;
+  }
+
+  //
+  // Now that we know the name exists, get it.
+  //
+  PolicyName = GET_POLICY_NAME (EvalEntry);
+
+  //
+  // Evaluate the name against the policy name and check for a match.
+  // Account for any wildcards.
+  //
+  Index = 0;
+  Result = TRUE;
+  //
+  // Keep going until the end of both strings.
+  //
+  while (PolicyName[Index] != CHAR_NULL || VariableName[Index] != CHAR_NULL) {
+    //
+    // If we don't have a match...
+    //
+    if (PolicyName[Index] != VariableName[Index] || PolicyName[Index] == '#') {
+      //
+      // If this is a numerical wildcard, we can consider it a match if we alter
+      // the priority.
+      //
+      if (PolicyName[Index] == L'#' &&
+            ((L'0' <= VariableName[Index] && VariableName[Index] <= L'9') ||
+             (L'A' <= VariableName[Index] && VariableName[Index] <= L'F') ||
+             (L'a' <= VariableName[Index] && VariableName[Index] <= L'f'))) {
+        if (CalculatedPriority < MATCH_PRIORITY_MIN) {
+          CalculatedPriority++;
+        }
+      //
+      // Otherwise, not a match.
+      //
+      } else {
+        Result = FALSE;
+        goto Exit;
+      }
+    }
+    Index++;
+  }
+
+Exit:
+  if (Result && MatchPriority != NULL) {
+    *MatchPriority = CalculatedPriority;
+  }
+  return Result;
+}
+
+/**
+  This helper function walks the current policy table and returns a pointer
+  to the best match, if any are found. Leverages EvaluatePolicyMatch() to
+  determine "best".
+
+  @param[in]  PolicyTable      Pointer to current policy table.
+  @param[in]  PolicyTableSize  Size of current policy table.
+  @param[in]  VariableName     Same as EFI_SET_VARIABLE.
+  @param[in]  VendorGuid       Same as EFI_SET_VARIABLE.
+  @param[out] ReturnPriority   [Optional] If pointer is provided, return the
+                               priority of the match. Same as EvaluatePolicyMatch().
+                               Only valid if a match is returned.
+
+  @retval     VARIABLE_POLICY_ENTRY*    Best match that was found.
+  @retval     NULL                      No match was found.
+
+**/
+STATIC
+VARIABLE_POLICY_ENTRY*
+GetBestPolicyMatch (
+  IN UINT8           *PolicyTable,
+  IN UINT32          PolicyTableSize,
+  IN CONST CHAR16    *VariableName,
+  IN CONST EFI_GUID  *VendorGuid,
+  OUT UINT8          *ReturnPriority  OPTIONAL
+  )
+{
+  VARIABLE_POLICY_ENTRY  *BestResult;
+  VARIABLE_POLICY_ENTRY  *CurrentEntry;
+  UINT8                  MatchPriority;
+  UINT8                  CurrentPriority;
+
+  BestResult = NULL;
+  MatchPriority = MATCH_PRIORITY_EXACT;
+
+  //
+  // Walk all entries in the table, looking for matches.
+  //
+  CurrentEntry = (VARIABLE_POLICY_ENTRY*)PolicyTable;
+  while ((UINTN)CurrentEntry < (UINTN)((UINT8*)PolicyTable + PolicyTableSize)) {
+    //
+    // Check for a match.
+    //
+    if (EvaluatePolicyMatch (CurrentEntry, VariableName, VendorGuid, &CurrentPriority)) {
+      //
+      // If match is better, take it.
+      //
+      if (BestResult == NULL || CurrentPriority < MatchPriority) {
+        BestResult = CurrentEntry;
+        MatchPriority = CurrentPriority;
+      }
+
+      //
+      // If you've hit the highest-priority match, can exit now.
+      //
+      if (MatchPriority == 0) {
+        break;
+      }
+    }
+
+    //
+    // If we're still in the loop, move to the next entry.
+    //
+    CurrentEntry = GET_NEXT_POLICY (CurrentEntry);
+  }
+
+  //
+  // If a return priority was requested, return it.
+  //
+  if (ReturnPriority != NULL) {
+    *ReturnPriority = MatchPriority;
+  }
+
+  return BestResult;
+}
+
+/**
+  This helper function will dump and walk the current policy tables to determine
+  whether a matching policy already exists that satisfies the lock request.
+
+  @param[in] VariableName  A pointer to the variable name that is being searched.
+  @param[in] VendorGuid    A pointer to the vendor GUID that is being searched.
+
+  @retval  TRUE   We can safely assume this variable is locked.
+  @retval  FALSE  An error has occurred or we cannot prove that the variable is
+                  locked.
+
+**/
+STATIC
+BOOLEAN
+IsVariableAlreadyLocked (
+  IN CHAR16    *VariableName,
+  IN EFI_GUID  *VendorGuid
+  )
+{
+  EFI_STATUS             Status;
+  UINT8                  *PolicyTable;
+  UINT32                 PolicyTableSize;
+  BOOLEAN                Result;
+  VARIABLE_POLICY_ENTRY  *MatchPolicy;
+  UINT8                  MatchPriority;
+
+  Result = TRUE;
+
+  //
+  // First, we need to dump the existing policy table.
+  //
+  PolicyTableSize = 0;
+  PolicyTable = NULL;
+  Status = DumpVariablePolicy (PolicyTable, &PolicyTableSize);
+  if (Status != EFI_BUFFER_TOO_SMALL) {
+    DEBUG ((DEBUG_ERROR, "%a - Failed to determine policy table size! %r\n", __FUNCTION__, Status));
+    return FALSE;
+  }
+  PolicyTable = AllocateZeroPool (PolicyTableSize);
+  if (PolicyTable == NULL) {
+    DEBUG ((DEBUG_ERROR, "%a - Failed to allocated space for policy table! 0x%X\n", __FUNCTION__, PolicyTableSize));
+    return FALSE;
+  }
+  Status = DumpVariablePolicy (PolicyTable, &PolicyTableSize);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR, "%a - Failed to dump policy table! %r\n", __FUNCTION__, Status));
+    Result = FALSE;
+    goto Exit;
+  }
+
+  //
+  // Now we need to walk the table looking for a match.
+  //
+  MatchPolicy = GetBestPolicyMatch (
+                  PolicyTable,
+                  PolicyTableSize,
+                  VariableName,
+                  VendorGuid,
+                  &MatchPriority
+                  );
+  if (MatchPolicy != NULL && MatchPriority != MATCH_PRIORITY_EXACT) {
+    DEBUG ((DEBUG_ERROR, "%a - We would not have expected a non-exact match! %d\n", __FUNCTION__, MatchPriority));
+    Result = FALSE;
+    goto Exit;
+  }
+
+  //
+  // Now we can check to see whether this variable is currently locked.
+  //
+  if (MatchPolicy->LockPolicyType != VARIABLE_POLICY_TYPE_LOCK_NOW) {
+    DEBUG ((DEBUG_INFO, "%a - Policy may not lock variable! %d\n", __FUNCTION__, MatchPolicy->LockPolicyType));
+    Result = FALSE;
+    goto Exit;
+  }
+
+Exit:
+  if (PolicyTable != NULL) {
+    FreePool (PolicyTable);
+  }
+
+  return Result;
+}
 
 /**
   DEPRECATED. THIS IS ONLY HERE AS A CONVENIENCE WHILE PORTING.
-  Mark a variable that will become read-only after leaving the DXE phase of execution.
-  Write request coming from SMM environment through EFI_SMM_VARIABLE_PROTOCOL is allowed.
+  Mark a variable that will become read-only after leaving the DXE phase of
+  execution. Write request coming from SMM environment through
+  EFI_SMM_VARIABLE_PROTOCOL is allowed.
 
   @param[in] This          The VARIABLE_LOCK_PROTOCOL instance.
-  @param[in] VariableName  A pointer to the variable name that will be made read-only subsequently.
-  @param[in] VendorGuid    A pointer to the vendor GUID that will be made read-only subsequently.
+  @param[in] VariableName  A pointer to the variable name that will be made
+                           read-only subsequently.
+  @param[in] VendorGuid    A pointer to the vendor GUID that will be made
+                           read-only subsequently.
 
-  @retval EFI_SUCCESS           The variable specified by the VariableName and the VendorGuid was marked
-                                as pending to be read-only.
+  @retval EFI_SUCCESS           The variable specified by the VariableName and
+                                the VendorGuid was marked as pending to be
+                                read-only.
   @retval EFI_INVALID_PARAMETER VariableName or VendorGuid is NULL.
                                 Or VariableName is an empty string.
-  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or EFI_EVENT_GROUP_READY_TO_BOOT has
-                                already been signaled.
-  @retval EFI_OUT_OF_RESOURCES  There is not enough resource to hold the lock request.
+  @retval EFI_ACCESS_DENIED     EFI_END_OF_DXE_EVENT_GROUP_GUID or
+                                EFI_EVENT_GROUP_READY_TO_BOOT has already been
+                                signaled.
+  @retval EFI_OUT_OF_RESOURCES  There is not enough resource to hold the lock
+                                request.
 **/
 EFI_STATUS
 EFIAPI
 VariableLockRequestToLock (
-  IN CONST EDKII_VARIABLE_LOCK_PROTOCOL *This,
-  IN       CHAR16                       *VariableName,
-  IN       EFI_GUID                     *VendorGuid
+  IN CONST EDKII_VARIABLE_LOCK_PROTOCOL  *This,
+  IN CHAR16                              *VariableName,
+  IN EFI_GUID                            *VendorGuid
   )
 {
-  EFI_STATUS              Status;
-  VARIABLE_POLICY_ENTRY   *NewPolicy;
+  EFI_STATUS             Status;
+  VARIABLE_POLICY_ENTRY  *NewPolicy;
+
+  DEBUG ((DEBUG_ERROR, "!!! DEPRECATED INTERFACE !!! %a() will go away soon!\n", __FUNCTION__));
+  DEBUG ((DEBUG_ERROR, "!!! DEPRECATED INTERFACE !!! Please move to use Variable Policy!\n"));
+  DEBUG ((DEBUG_ERROR, "!!! DEPRECATED INTERFACE !!! Variable: %g %s\n", VendorGuid, VariableName));
 
   NewPolicy = NULL;
-  Status = CreateBasicVariablePolicy( VendorGuid,
-                                      VariableName,
-                                      VARIABLE_POLICY_NO_MIN_SIZE,
-                                      VARIABLE_POLICY_NO_MAX_SIZE,
-                                      VARIABLE_POLICY_NO_MUST_ATTR,
-                                      VARIABLE_POLICY_NO_CANT_ATTR,
-                                      VARIABLE_POLICY_TYPE_LOCK_NOW,
-                                      &NewPolicy );
+  Status = CreateBasicVariablePolicy(
+             VendorGuid,
+             VariableName,
+             VARIABLE_POLICY_NO_MIN_SIZE,
+             VARIABLE_POLICY_NO_MAX_SIZE,
+             VARIABLE_POLICY_NO_MUST_ATTR,
+             VARIABLE_POLICY_NO_CANT_ATTR,
+             VARIABLE_POLICY_TYPE_LOCK_NOW,
+             &NewPolicy
+             );
   if (!EFI_ERROR( Status )) {
-    Status = RegisterVariablePolicy( NewPolicy );
+    Status = RegisterVariablePolicy (NewPolicy);
+
+    //
+    // If the error returned is EFI_ALREADY_STARTED, we need to check the
+    // current database for the variable and see whether it's locked. If it's
+    // locked, we're still fine, but also generate a DEBUG_ERROR message so the
+    // duplicate lock can be removed.
+    //
+    if (Status == EFI_ALREADY_STARTED) {
+      if (IsVariableAlreadyLocked (VariableName, VendorGuid)) {
+        DEBUG ((DEBUG_ERROR, "  Variable: %g %s is already locked!\n", VendorGuid, VariableName));
+        Status = EFI_SUCCESS;
+      }
+    }
   }
-  if (EFI_ERROR( Status )) {
+  if (EFI_ERROR (Status)) {
     DEBUG(( DEBUG_ERROR, "%a - Failed to lock variable %s! %r\n", __FUNCTION__, VariableName, Status ));
-    ASSERT_EFI_ERROR( Status );
   }
   if (NewPolicy != NULL) {
     FreePool( NewPolicy );
-- 
2.29.2.windows.2


^ permalink raw reply related	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-12-11  1:40 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-12-09 18:06 [Patch v2 1/1] MdeModulePkg/Variable/RuntimeDxe: Restore Variable Lock Protocol behavior Michael D Kinney
2020-12-10  2:24 ` [edk2-devel] " Wu, Hao A
2020-12-10  3:16   ` 回复: " gaoliming
2020-12-10  7:18     ` Michael D Kinney
2020-12-10  7:34     ` [EXTERNAL] 回复: " Bret Barkelew
2020-12-11  0:42       ` Wu, Hao A
2020-12-11  1:31         ` 回复: " gaoliming
2020-12-11  1:38           ` Michael D Kinney

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