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/** @file -- VariablePolicyHelperLib.c
This library contains helper functions for marshalling and registering
new policies with the VariablePolicy infrastructure.
This library is currently written against VariablePolicy revision 0x00010000.
Copyright (c) Microsoft Corporation.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Uefi.h>
#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Protocol/VariablePolicy.h>
/**
This internal helper function populates the header structure,
all common fields, and takes care of fix-ups.
NOTE: Only use this internally. Assumes correctly-sized buffers.
@param[out] EntPtr Pointer to the buffer to be populated.
@param[in] Namespace Pointer to an EFI_GUID for the target variable namespace that this policy will protect.
@param[in] MinSize MinSize for the VariablePolicy.
@param[in] MaxSize MaxSize for the VariablePolicy.
@param[in] AttributesMustHave AttributesMustHave for the VariablePolicy.
@param[in] AttributesCantHave AttributesCantHave for the VariablePolicy.
@param[in] LockPolicyType LockPolicyType for the VariablePolicy.
**/
STATIC
VOID
PopulateCommonData (
OUT VARIABLE_POLICY_ENTRY *EntPtr,
IN CONST EFI_GUID *Namespace,
IN UINT32 MinSize,
IN UINT32 MaxSize,
IN UINT32 AttributesMustHave,
IN UINT32 AttributesCantHave,
IN UINT8 LockPolicyType
)
{
EntPtr->Version = VARIABLE_POLICY_ENTRY_REVISION;
CopyGuid (&EntPtr->Namespace, Namespace);
EntPtr->MinSize = MinSize;
EntPtr->MaxSize = MaxSize;
EntPtr->AttributesMustHave = AttributesMustHave;
EntPtr->AttributesCantHave = AttributesCantHave;
EntPtr->LockPolicyType = LockPolicyType;
// NOTE: As a heler, fix up MaxSize for compatibility with the old model.
if (EntPtr->MaxSize == 0) {
EntPtr->MaxSize = VARIABLE_POLICY_NO_MAX_SIZE;
}
return;
}
/**
This helper function will allocate and populate a new VariablePolicy
structure for a policy that does not contain any sub-structures (such as
VARIABLE_LOCK_ON_VAR_STATE_POLICY).
NOTE: Caller will need to free structure once finished.
@param[in] Namespace Pointer to an EFI_GUID for the target variable namespace that this policy will protect.
@param[in] Name [Optional] If provided, a pointer to the CHAR16 array for the target variable name.
Otherwise, will create a policy that targets an entire namespace.
@param[in] MinSize MinSize for the VariablePolicy.
@param[in] MaxSize MaxSize for the VariablePolicy.
@param[in] AttributesMustHave AttributesMustHave for the VariablePolicy.
@param[in] AttributesCantHave AttributesCantHave for the VariablePolicy.
@param[in] LockPolicyType LockPolicyType for the VariablePolicy.
@param[out] NewEntry If successful, will be set to a pointer to the allocated buffer containing the
new policy.
@retval EFI_SUCCESS Operation completed successfully and structure is populated.
@retval EFI_INVALID_PARAMETER Namespace is NULL.
@retval EFI_INVALID_PARAMETER LockPolicyType is invalid for a basic structure.
@retval EFI_BUFFER_TOO_SMALL Finished structure would not fit in UINT16 size.
@retval EFI_OUT_OF_RESOURCES Could not allocate sufficient space for structure.
**/
EFI_STATUS
EFIAPI
CreateBasicVariablePolicy (
IN CONST EFI_GUID *Namespace,
IN CONST CHAR16 *Name OPTIONAL,
IN UINT32 MinSize,
IN UINT32 MaxSize,
IN UINT32 AttributesMustHave,
IN UINT32 AttributesCantHave,
IN UINT8 LockPolicyType,
OUT VARIABLE_POLICY_ENTRY **NewEntry
)
{
UINTN TotalSize;
UINTN NameSize;
VARIABLE_POLICY_ENTRY *EntPtr;
CHAR16 *CopyName;
// Check some initial invalid parameters for this function.
if ((Namespace == NULL) || (NewEntry == NULL)) {
return EFI_INVALID_PARAMETER;
}
if ((LockPolicyType != VARIABLE_POLICY_TYPE_NO_LOCK) &&
(LockPolicyType != VARIABLE_POLICY_TYPE_LOCK_NOW) &&
(LockPolicyType != VARIABLE_POLICY_TYPE_LOCK_ON_CREATE))
{
return EFI_INVALID_PARAMETER;
}
//
// Set NameSize to suppress incorrect compiler/analyzer warnings
//
NameSize = 0;
// Now we've gotta determine the total size of the buffer required for
// the VariablePolicy structure.
TotalSize = sizeof (VARIABLE_POLICY_ENTRY);
if (Name != NULL) {
NameSize = StrnSizeS (Name, MAX_UINT16);
TotalSize += NameSize;
}
// Make sure the size fits within a VARIABLE_POLICY_ENTRY.Size.
ASSERT (TotalSize <= MAX_UINT16);
if (TotalSize > MAX_UINT16) {
return EFI_BUFFER_TOO_SMALL;
}
// Allocate a buffer to hold all the data. We're on the home stretch.
*NewEntry = AllocatePool (TotalSize);
if (*NewEntry == NULL) {
return EFI_OUT_OF_RESOURCES;
}
// If we're still here, we're basically done.
// Copy the data and GET... OUT....
EntPtr = *NewEntry;
PopulateCommonData (
EntPtr,
Namespace,
MinSize,
MaxSize,
AttributesMustHave,
AttributesCantHave,
LockPolicyType
);
EntPtr->Size = (UINT16)TotalSize; // This is safe because we've already checked.
EntPtr->OffsetToName = sizeof (VARIABLE_POLICY_ENTRY);
if (Name != NULL) {
CopyName = (CHAR16 *)((UINT8 *)EntPtr + EntPtr->OffsetToName);
CopyMem (CopyName, Name, NameSize);
}
return EFI_SUCCESS;
}
/**
This helper function will allocate and populate a new VariablePolicy
structure for a policy with a lock type of VARIABLE_POLICY_TYPE_LOCK_ON_VAR_STATE.
NOTE: Caller will need to free structure once finished.
@param[in] Namespace Pointer to an EFI_GUID for the target variable namespace that this policy will protect.
@param[in] Name [Optional] If provided, a pointer to the CHAR16 array for the target variable name.
Otherwise, will create a policy that targets an entire namespace.
@param[in] MinSize MinSize for the VariablePolicy.
@param[in] MaxSize MaxSize for the VariablePolicy.
@param[in] AttributesMustHave AttributesMustHave for the VariablePolicy.
@param[in] AttributesCantHave AttributesCantHave for the VariablePolicy.
@param[in] VarStateNamespace Pointer to the EFI_GUID for the VARIABLE_LOCK_ON_VAR_STATE_POLICY.Namespace.
@param[in] VarStateValue Value for the VARIABLE_LOCK_ON_VAR_STATE_POLICY.Value.
@param[in] VarStateName Pointer to the CHAR16 array for the VARIABLE_LOCK_ON_VAR_STATE_POLICY.Name.
@param[out] NewEntry If successful, will be set to a pointer to the allocated buffer containing the
new policy.
@retval EFI_SUCCESS Operation completed successfully and structure is populated.
@retval EFI_INVALID_PARAMETER Namespace, VarStateNamespace, VarStateName is NULL.
@retval EFI_BUFFER_TOO_SMALL Finished structure would not fit in UINT16 size.
@retval EFI_OUT_OF_RESOURCES Could not allocate sufficient space for structure.
**/
EFI_STATUS
EFIAPI
CreateVarStateVariablePolicy (
IN CONST EFI_GUID *Namespace,
IN CONST CHAR16 *Name OPTIONAL,
IN UINT32 MinSize,
IN UINT32 MaxSize,
IN UINT32 AttributesMustHave,
IN UINT32 AttributesCantHave,
IN CONST EFI_GUID *VarStateNamespace,
IN UINT8 VarStateValue,
IN CONST CHAR16 *VarStateName,
OUT VARIABLE_POLICY_ENTRY **NewEntry
)
{
UINTN TotalSize;
UINTN NameSize;
UINTN VarStateNameSize;
VARIABLE_POLICY_ENTRY *EntPtr;
CHAR16 *CopyName;
VARIABLE_LOCK_ON_VAR_STATE_POLICY *CopyPolicy;
// Check some initial invalid parameters for this function.
if ((Namespace == NULL) || (VarStateNamespace == NULL) ||
(VarStateName == NULL) || (NewEntry == NULL))
{
return EFI_INVALID_PARAMETER;
}
// Now we've gotta determine the total size of the buffer required for
// the VariablePolicy structure.
VarStateNameSize = StrnSizeS (VarStateName, MAX_UINT16);
TotalSize = sizeof (VARIABLE_POLICY_ENTRY) +
sizeof (VARIABLE_LOCK_ON_VAR_STATE_POLICY) +
VarStateNameSize;
if (Name != NULL) {
NameSize = StrnSizeS (Name, MAX_UINT16);
TotalSize += NameSize;
}
// Make sure the size fits within a VARIABLE_POLICY_ENTRY.Size.
ASSERT (TotalSize <= MAX_UINT16);
if (TotalSize > MAX_UINT16) {
return EFI_BUFFER_TOO_SMALL;
}
// Allocate a buffer to hold all the data. We're on the home stretch.
*NewEntry = AllocatePool (TotalSize);
if (*NewEntry == NULL) {
return EFI_OUT_OF_RESOURCES;
}
// If we're still here, we're basically done.
// Copy the data and GET... OUT....
EntPtr = *NewEntry;
PopulateCommonData (
EntPtr,
Namespace,
MinSize,
MaxSize,
AttributesMustHave,
AttributesCantHave,
VARIABLE_POLICY_TYPE_LOCK_ON_VAR_STATE
);
EntPtr->Size = (UINT16)TotalSize; // This is safe because we've already checked.
EntPtr->OffsetToName = sizeof (VARIABLE_POLICY_ENTRY) +
sizeof (VARIABLE_LOCK_ON_VAR_STATE_POLICY) +
(UINT16)VarStateNameSize;
CopyPolicy = (VARIABLE_LOCK_ON_VAR_STATE_POLICY *)((UINT8 *)EntPtr + sizeof (VARIABLE_POLICY_ENTRY));
CopyName = (CHAR16 *)((UINT8 *)CopyPolicy + sizeof (VARIABLE_LOCK_ON_VAR_STATE_POLICY));
CopyGuid (&CopyPolicy->Namespace, VarStateNamespace);
CopyPolicy->Value = VarStateValue;
CopyMem (CopyName, VarStateName, VarStateNameSize);
if (Name != NULL) {
CopyName = (CHAR16 *)((UINT8 *)EntPtr + EntPtr->OffsetToName);
CopyMem (CopyName, Name, NameSize);
}
return EFI_SUCCESS;
}
/**
This helper function does everything that CreateBasicVariablePolicy() does, but also
uses the passed in protocol to register the policy with the infrastructure.
Does not return a buffer, does not require the caller to free anything.
@param[in] VariablePolicy Pointer to a valid instance of the VariablePolicy protocol.
@param[in] Namespace Pointer to an EFI_GUID for the target variable namespace that this policy will protect.
@param[in] Name [Optional] If provided, a pointer to the CHAR16 array for the target variable name.
Otherwise, will create a policy that targets an entire namespace.
@param[in] MinSize MinSize for the VariablePolicy.
@param[in] MaxSize MaxSize for the VariablePolicy.
@param[in] AttributesMustHave AttributesMustHave for the VariablePolicy.
@param[in] AttributesCantHave AttributesCantHave for the VariablePolicy.
@param[in] LockPolicyType LockPolicyType for the VariablePolicy.
@retval EFI_INVALID_PARAMETER VariablePolicy pointer is NULL.
@retval EFI_STATUS Status returned by CreateBasicVariablePolicy() or RegisterVariablePolicy().
**/
EFI_STATUS
EFIAPI
RegisterBasicVariablePolicy (
IN EDKII_VARIABLE_POLICY_PROTOCOL *VariablePolicy,
IN CONST EFI_GUID *Namespace,
IN CONST CHAR16 *Name OPTIONAL,
IN UINT32 MinSize,
IN UINT32 MaxSize,
IN UINT32 AttributesMustHave,
IN UINT32 AttributesCantHave,
IN UINT8 LockPolicyType
)
{
VARIABLE_POLICY_ENTRY *NewEntry;
EFI_STATUS Status;
// Check the simple things.
if (VariablePolicy == NULL) {
return EFI_INVALID_PARAMETER;
}
// Create the new entry and make sure that everything worked.
NewEntry = NULL;
Status = CreateBasicVariablePolicy (
Namespace,
Name,
MinSize,
MaxSize,
AttributesMustHave,
AttributesCantHave,
LockPolicyType,
&NewEntry
);
// If that was successful, attempt to register the new policy.
if (!EFI_ERROR (Status)) {
Status = VariablePolicy->RegisterVariablePolicy (NewEntry);
}
// If we allocated the buffer, free the buffer.
if (NewEntry != NULL) {
FreePool (NewEntry);
}
return Status;
}
/**
This helper function does everything that CreateBasicVariablePolicy() does, but also
uses the passed in protocol to register the policy with the infrastructure.
Does not return a buffer, does not require the caller to free anything.
@param[in] VariablePolicy Pointer to a valid instance of the VariablePolicy protocol.
@param[in] Namespace Pointer to an EFI_GUID for the target variable namespace that this policy will protect.
@param[in] Name [Optional] If provided, a pointer to the CHAR16 array for the target variable name.
Otherwise, will create a policy that targets an entire namespace.
@param[in] MinSize MinSize for the VariablePolicy.
@param[in] MaxSize MaxSize for the VariablePolicy.
@param[in] AttributesMustHave AttributesMustHave for the VariablePolicy.
@param[in] AttributesCantHave AttributesCantHave for the VariablePolicy.
@param[in] VarStateNamespace Pointer to the EFI_GUID for the VARIABLE_LOCK_ON_VAR_STATE_POLICY.Namespace.
@param[in] VarStateName Pointer to the CHAR16 array for the VARIABLE_LOCK_ON_VAR_STATE_POLICY.Name.
@param[in] VarStateValue Value for the VARIABLE_LOCK_ON_VAR_STATE_POLICY.Value.
@retval EFI_INVALID_PARAMETER VariablePolicy pointer is NULL.
@retval EFI_STATUS Status returned by CreateBasicVariablePolicy() or RegisterVariablePolicy().
**/
EFI_STATUS
EFIAPI
RegisterVarStateVariablePolicy (
IN EDKII_VARIABLE_POLICY_PROTOCOL *VariablePolicy,
IN CONST EFI_GUID *Namespace,
IN CONST CHAR16 *Name OPTIONAL,
IN UINT32 MinSize,
IN UINT32 MaxSize,
IN UINT32 AttributesMustHave,
IN UINT32 AttributesCantHave,
IN CONST EFI_GUID *VarStateNamespace,
IN CONST CHAR16 *VarStateName,
IN UINT8 VarStateValue
)
{
VARIABLE_POLICY_ENTRY *NewEntry;
EFI_STATUS Status;
// Check the simple things.
if (VariablePolicy == NULL) {
return EFI_INVALID_PARAMETER;
}
// Create the new entry and make sure that everything worked.
NewEntry = NULL;
Status = CreateVarStateVariablePolicy (
Namespace,
Name,
MinSize,
MaxSize,
AttributesMustHave,
AttributesCantHave,
VarStateNamespace,
VarStateValue,
VarStateName,
&NewEntry
);
// If that was successful, attempt to register the new policy.
if (!EFI_ERROR (Status)) {
Status = VariablePolicy->RegisterVariablePolicy (NewEntry);
}
// If we allocated the buffer, free the buffer.
if (NewEntry != NULL) {
FreePool (NewEntry);
}
return Status;
}
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