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audk/SecurityPkg/Library/AuthVariableLib/AuthVariableLib.c

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/** @file
Implement authentication services for the authenticated variables.
Caution: This module requires additional review when modified.
This driver will have external input - variable data. It may be input in SMM mode.
This external input must be validated carefully to avoid security issue like
buffer overflow, integer overflow.
Variable attribute should also be checked to avoid authentication bypass.
The whole SMM authentication variable design relies on the integrity of flash part and SMM.
which is assumed to be protected by platform. All variable code and metadata in flash/SMM Memory
may not be modified without authorization. If platform fails to protect these resources,
the authentication service provided in this driver will be broken, and the behavior is undefined.
Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "AuthServiceInternal.h"
///
/// Global database array for scratch
///
UINT8 *mPubKeyStore;
UINT32 mPubKeyNumber;
UINT32 mMaxKeyNumber;
UINT32 mMaxKeyDbSize;
UINT8 *mCertDbStore;
UINT32 mMaxCertDbSize;
UINT32 mPlatformMode;
UINT8 mVendorKeyState;
EFI_GUID mSignatureSupport[] = {EFI_CERT_SHA1_GUID, EFI_CERT_SHA256_GUID, EFI_CERT_RSA2048_GUID, EFI_CERT_X509_GUID};
//
// Hash context pointer
//
VOID *mHashCtx = NULL;
VARIABLE_ENTRY_PROPERTY mAuthVarEntry[] = {
{
&gEfiSecureBootEnableDisableGuid,
EFI_SECURE_BOOT_ENABLE_NAME,
{
VAR_CHECK_VARIABLE_PROPERTY_REVISION,
0,
VARIABLE_ATTRIBUTE_NV_BS,
sizeof (UINT8),
sizeof (UINT8)
}
},
{
&gEfiCustomModeEnableGuid,
EFI_CUSTOM_MODE_NAME,
{
VAR_CHECK_VARIABLE_PROPERTY_REVISION,
0,
VARIABLE_ATTRIBUTE_NV_BS,
sizeof (UINT8),
sizeof (UINT8)
}
},
{
&gEfiVendorKeysNvGuid,
EFI_VENDOR_KEYS_NV_VARIABLE_NAME,
{
VAR_CHECK_VARIABLE_PROPERTY_REVISION,
VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY,
VARIABLE_ATTRIBUTE_NV_BS_RT_AT,
sizeof (UINT8),
sizeof (UINT8)
}
},
{
&gEfiAuthenticatedVariableGuid,
AUTHVAR_KEYDB_NAME,
{
VAR_CHECK_VARIABLE_PROPERTY_REVISION,
VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY,
VARIABLE_ATTRIBUTE_NV_BS_RT_AW,
sizeof (UINT8),
MAX_UINTN
}
},
{
&gEfiCertDbGuid,
EFI_CERT_DB_NAME,
{
VAR_CHECK_VARIABLE_PROPERTY_REVISION,
VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY,
VARIABLE_ATTRIBUTE_NV_BS_RT_AT,
sizeof (UINT32),
MAX_UINTN
}
},
};
VOID *mAddressPointer[3];
AUTH_VAR_LIB_CONTEXT_IN *mAuthVarLibContextIn = NULL;
/**
Initialization for authenticated varibale services.
If this initialization returns error status, other APIs will not work
and expect to be not called then.
@param[in] AuthVarLibContextIn Pointer to input auth variable lib context.
@param[out] AuthVarLibContextOut Pointer to output auth variable lib context.
@retval EFI_SUCCESS Function successfully executed.
@retval EFI_INVALID_PARAMETER If AuthVarLibContextIn == NULL or AuthVarLibContextOut == NULL.
@retval EFI_OUT_OF_RESOURCES Fail to allocate enough resource.
@retval EFI_UNSUPPORTED Unsupported to process authenticated variable.
**/
EFI_STATUS
EFIAPI
AuthVariableLibInitialize (
IN AUTH_VAR_LIB_CONTEXT_IN *AuthVarLibContextIn,
OUT AUTH_VAR_LIB_CONTEXT_OUT *AuthVarLibContextOut
)
{
EFI_STATUS Status;
UINT8 VarValue;
UINT32 VarAttr;
UINT8 *Data;
UINTN DataSize;
UINTN CtxSize;
UINT8 SecureBootMode;
UINT8 SecureBootEnable;
UINT8 CustomMode;
UINT32 ListSize;
if ((AuthVarLibContextIn == NULL) || (AuthVarLibContextOut == NULL)) {
return EFI_INVALID_PARAMETER;
}
mAuthVarLibContextIn = AuthVarLibContextIn;
//
// Initialize hash context.
//
CtxSize = Sha256GetContextSize ();
mHashCtx = AllocateRuntimePool (CtxSize);
if (mHashCtx == NULL) {
return EFI_OUT_OF_RESOURCES;
}
//
// Reserve runtime buffer for public key database. The size excludes variable header and name size.
//
mMaxKeyDbSize = (UINT32) (mAuthVarLibContextIn->MaxAuthVariableSize - sizeof (AUTHVAR_KEYDB_NAME));
mMaxKeyNumber = mMaxKeyDbSize / sizeof (AUTHVAR_KEY_DB_DATA);
mPubKeyStore = AllocateRuntimePool (mMaxKeyDbSize);
if (mPubKeyStore == NULL) {
return EFI_OUT_OF_RESOURCES;
}
//
// Reserve runtime buffer for certificate database. The size excludes variable header and name size.
//
mMaxCertDbSize = (UINT32) (mAuthVarLibContextIn->MaxAuthVariableSize - sizeof (EFI_CERT_DB_NAME));
mCertDbStore = AllocateRuntimePool (mMaxCertDbSize);
if (mCertDbStore == NULL) {
return EFI_OUT_OF_RESOURCES;
}
//
// Check "AuthVarKeyDatabase" variable's existence.
// If it doesn't exist, create a new one with initial value of 0 and EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS set.
//
Status = AuthServiceInternalFindVariable (
AUTHVAR_KEYDB_NAME,
&gEfiAuthenticatedVariableGuid,
(VOID **) &Data,
&DataSize
);
if (EFI_ERROR (Status)) {
VarAttr = EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS;
VarValue = 0;
mPubKeyNumber = 0;
Status = AuthServiceInternalUpdateVariable (
AUTHVAR_KEYDB_NAME,
&gEfiAuthenticatedVariableGuid,
&VarValue,
sizeof(UINT8),
VarAttr
);
if (EFI_ERROR (Status)) {
return Status;
}
} else {
//
// Load database in global variable for cache.
//
ASSERT ((DataSize != 0) && (Data != NULL));
//
// "AuthVarKeyDatabase" is an internal variable. Its DataSize is always ensured not to exceed mPubKeyStore buffer size(See definition before)
// Therefore, there is no memory overflow in underlying CopyMem.
//
CopyMem (mPubKeyStore, (UINT8 *) Data, DataSize);
mPubKeyNumber = (UINT32) (DataSize / sizeof (AUTHVAR_KEY_DB_DATA));
}
Status = AuthServiceInternalFindVariable (EFI_PLATFORM_KEY_NAME, &gEfiGlobalVariableGuid, (VOID **) &Data, &DataSize);
if (EFI_ERROR (Status)) {
DEBUG ((EFI_D_INFO, "Variable %s does not exist.\n", EFI_PLATFORM_KEY_NAME));
} else {
DEBUG ((EFI_D_INFO, "Variable %s exists.\n", EFI_PLATFORM_KEY_NAME));
}
//
// Create "SetupMode" variable with BS+RT attribute set.
//
if (EFI_ERROR (Status)) {
mPlatformMode = SETUP_MODE;
} else {
mPlatformMode = USER_MODE;
}
Status = AuthServiceInternalUpdateVariable (
EFI_SETUP_MODE_NAME,
&gEfiGlobalVariableGuid,
&mPlatformMode,
sizeof(UINT8),
EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Create "SignatureSupport" variable with BS+RT attribute set.
//
Status = AuthServiceInternalUpdateVariable (
EFI_SIGNATURE_SUPPORT_NAME,
&gEfiGlobalVariableGuid,
mSignatureSupport,
sizeof(mSignatureSupport),
EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// If "SecureBootEnable" variable exists, then update "SecureBoot" variable.
// If "SecureBootEnable" variable is SECURE_BOOT_ENABLE and in USER_MODE, Set "SecureBoot" variable to SECURE_BOOT_MODE_ENABLE.
// If "SecureBootEnable" variable is SECURE_BOOT_DISABLE, Set "SecureBoot" variable to SECURE_BOOT_MODE_DISABLE.
//
SecureBootEnable = SECURE_BOOT_DISABLE;
Status = AuthServiceInternalFindVariable (EFI_SECURE_BOOT_ENABLE_NAME, &gEfiSecureBootEnableDisableGuid, (VOID **) &Data, &DataSize);
if (!EFI_ERROR (Status)) {
if (mPlatformMode == SETUP_MODE){
//
// PK is cleared in runtime. "SecureBootMode" is not updated before reboot
// Delete "SecureBootMode" in SetupMode
//
Status = AuthServiceInternalUpdateVariable (
EFI_SECURE_BOOT_ENABLE_NAME,
&gEfiSecureBootEnableDisableGuid,
&SecureBootEnable,
0,
EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS
);
} else {
SecureBootEnable = *(UINT8 *) Data;
}
} else if (mPlatformMode == USER_MODE) {
//
// "SecureBootEnable" not exist, initialize it in USER_MODE.
//
SecureBootEnable = SECURE_BOOT_ENABLE;
Status = AuthServiceInternalUpdateVariable (
EFI_SECURE_BOOT_ENABLE_NAME,
&gEfiSecureBootEnableDisableGuid,
&SecureBootEnable,
sizeof (UINT8),
EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS
);
if (EFI_ERROR (Status)) {
return Status;
}
}
//
// Create "SecureBoot" variable with BS+RT attribute set.
//
if (SecureBootEnable == SECURE_BOOT_ENABLE && mPlatformMode == USER_MODE) {
SecureBootMode = SECURE_BOOT_MODE_ENABLE;
} else {
SecureBootMode = SECURE_BOOT_MODE_DISABLE;
}
Status = AuthServiceInternalUpdateVariable (
EFI_SECURE_BOOT_MODE_NAME,
&gEfiGlobalVariableGuid,
&SecureBootMode,
sizeof (UINT8),
EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS
);
if (EFI_ERROR (Status)) {
return Status;
}
DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_SETUP_MODE_NAME, mPlatformMode));
DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_SECURE_BOOT_MODE_NAME, SecureBootMode));
DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_SECURE_BOOT_ENABLE_NAME, SecureBootEnable));
//
// Initialize "CustomMode" in STANDARD_SECURE_BOOT_MODE state.
//
CustomMode = STANDARD_SECURE_BOOT_MODE;
Status = AuthServiceInternalUpdateVariable (
EFI_CUSTOM_MODE_NAME,
&gEfiCustomModeEnableGuid,
&CustomMode,
sizeof (UINT8),
EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS
);
if (EFI_ERROR (Status)) {
return Status;
}
DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_CUSTOM_MODE_NAME, CustomMode));
//
// Check "certdb" variable's existence.
// If it doesn't exist, then create a new one with
// EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set.
//
Status = AuthServiceInternalFindVariable (
EFI_CERT_DB_NAME,
&gEfiCertDbGuid,
(VOID **) &Data,
&DataSize
);
if (EFI_ERROR (Status)) {
VarAttr = EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
ListSize = sizeof (UINT32);
Status = AuthServiceInternalUpdateVariable (
EFI_CERT_DB_NAME,
&gEfiCertDbGuid,
&ListSize,
sizeof (UINT32),
VarAttr
);
if (EFI_ERROR (Status)) {
return Status;
}
}
//
// Check "VendorKeysNv" variable's existence and create "VendorKeys" variable accordingly.
//
Status = AuthServiceInternalFindVariable (EFI_VENDOR_KEYS_NV_VARIABLE_NAME, &gEfiVendorKeysNvGuid, (VOID **) &Data, &DataSize);
if (!EFI_ERROR (Status)) {
mVendorKeyState = *(UINT8 *)Data;
} else {
//
// "VendorKeysNv" not exist, initialize it in VENDOR_KEYS_VALID state.
//
mVendorKeyState = VENDOR_KEYS_VALID;
Status = AuthServiceInternalUpdateVariable (
EFI_VENDOR_KEYS_NV_VARIABLE_NAME,
&gEfiVendorKeysNvGuid,
&mVendorKeyState,
sizeof (UINT8),
EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
);
if (EFI_ERROR (Status)) {
return Status;
}
}
//
// Create "VendorKeys" variable with BS+RT attribute set.
//
Status = AuthServiceInternalUpdateVariable (
EFI_VENDOR_KEYS_VARIABLE_NAME,
&gEfiGlobalVariableGuid,
&mVendorKeyState,
sizeof (UINT8),
EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS
);
if (EFI_ERROR (Status)) {
return Status;
}
DEBUG ((EFI_D_INFO, "Variable %s is %x\n", EFI_VENDOR_KEYS_VARIABLE_NAME, mVendorKeyState));
AuthVarLibContextOut->StructVersion = AUTH_VAR_LIB_CONTEXT_OUT_STRUCT_VERSION;
AuthVarLibContextOut->StructSize = sizeof (AUTH_VAR_LIB_CONTEXT_OUT);
AuthVarLibContextOut->AuthVarEntry = mAuthVarEntry;
AuthVarLibContextOut->AuthVarEntryCount = sizeof (mAuthVarEntry) / sizeof (mAuthVarEntry[0]);
mAddressPointer[0] = mHashCtx;
mAddressPointer[1] = mPubKeyStore;
mAddressPointer[2] = mCertDbStore;
AuthVarLibContextOut->AddressPointer = mAddressPointer;
AuthVarLibContextOut->AddressPointerCount = sizeof (mAddressPointer) / sizeof (mAddressPointer[0]);
return Status;
}
/**
Process variable with EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS/EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set.
@param[in] VariableName Name of the variable.
@param[in] VendorGuid Variable vendor GUID.
@param[in] Data Data pointer.
@param[in] DataSize Size of Data.
@param[in] Attributes Attribute value of the variable.
@retval EFI_SUCCESS The firmware has successfully stored the variable and its data as
defined by the Attributes.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_WRITE_PROTECTED Variable is write-protected.
@retval EFI_OUT_OF_RESOURCES There is not enough resource.
@retval EFI_SECURITY_VIOLATION The variable is with EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS
or EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACESS
set, but the AuthInfo does NOT pass the validation
check carried out by the firmware.
@retval EFI_UNSUPPORTED Unsupported to process authenticated variable.
**/
EFI_STATUS
EFIAPI
AuthVariableLibProcessVariable (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN VOID *Data,
IN UINTN DataSize,
IN UINT32 Attributes
)
{
EFI_STATUS Status;
if (CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) && (StrCmp (VariableName, EFI_PLATFORM_KEY_NAME) == 0)){
Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, Attributes, TRUE);
} else if (CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) && (StrCmp (VariableName, EFI_KEY_EXCHANGE_KEY_NAME) == 0)) {
Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, Attributes, FALSE);
} else if (CompareGuid (VendorGuid, &gEfiImageSecurityDatabaseGuid) &&
((StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) ||
(StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE1) == 0) ||
(StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE2) == 0)
)) {
Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, Attributes, FALSE);
if (EFI_ERROR (Status)) {
Status = ProcessVarWithKek (VariableName, VendorGuid, Data, DataSize, Attributes);
}
} else {
Status = ProcessVariable (VariableName, VendorGuid, Data, DataSize, Attributes);
}
return Status;
}
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