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qemu / edk2 / refs/heads/StructurePcd / . / SecurityPkg / Library / AuthVariableLib / AuthService.c
blob: a37ec0bd0fc604f4333d29fdeb89fb4c2b119bcd [file] [log] [blame]
/** @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.
ProcessVarWithPk(), ProcessVarWithKek() and ProcessVariable() are the function to do
variable authentication.
VerifyTimeBasedPayloadAndUpdate() and VerifyCounterBasedPayload() are sub function to do verification.
They will do basic validation for authentication data structure, then call crypto library
to verify the signature.
Copyright (c) 2009 - 2017, 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"
//
// Public Exponent of RSA Key.
//
CONST UINT8 mRsaE[] = { 0x01, 0x00, 0x01 };
CONST UINT8 mSha256OidValue[] = { 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01 };
//
// Requirement for different signature type which have been defined in UEFI spec.
// These data are used to perform SignatureList format check while setting PK/KEK variable.
//
EFI_SIGNATURE_ITEM mSupportSigItem[] = {
//{SigType, SigHeaderSize, SigDataSize }
{EFI_CERT_SHA256_GUID, 0, 32 },
{EFI_CERT_RSA2048_GUID, 0, 256 },
{EFI_CERT_RSA2048_SHA256_GUID, 0, 256 },
{EFI_CERT_SHA1_GUID, 0, 20 },
{EFI_CERT_RSA2048_SHA1_GUID, 0, 256 },
{EFI_CERT_X509_GUID, 0, ((UINT32) ~0)},
{EFI_CERT_SHA224_GUID, 0, 28 },
{EFI_CERT_SHA384_GUID, 0, 48 },
{EFI_CERT_SHA512_GUID, 0, 64 },
{EFI_CERT_X509_SHA256_GUID, 0, 48 },
{EFI_CERT_X509_SHA384_GUID, 0, 64 },
{EFI_CERT_X509_SHA512_GUID, 0, 80 }
};
/**
Finds variable in storage blocks of volatile and non-volatile storage areas.
This code finds variable in storage blocks of volatile and non-volatile storage areas.
If VariableName is an empty string, then we just return the first
qualified variable without comparing VariableName and VendorGuid.
@param[in] VariableName Name of the variable to be found.
@param[in] VendorGuid Variable vendor GUID to be found.
@param[out] Data Pointer to data address.
@param[out] DataSize Pointer to data size.
@retval EFI_INVALID_PARAMETER If VariableName is not an empty string,
while VendorGuid is NULL.
@retval EFI_SUCCESS Variable successfully found.
@retval EFI_NOT_FOUND Variable not found
**/
EFI_STATUS
AuthServiceInternalFindVariable (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
OUT VOID **Data,
OUT UINTN *DataSize
)
{
EFI_STATUS Status;
AUTH_VARIABLE_INFO AuthVariableInfo;
ZeroMem (&AuthVariableInfo, sizeof (AuthVariableInfo));
Status = mAuthVarLibContextIn->FindVariable (
VariableName,
VendorGuid,
&AuthVariableInfo
);
*Data = AuthVariableInfo.Data;
*DataSize = AuthVariableInfo.DataSize;
return Status;
}
/**
Update the variable region with Variable information.
@param[in] VariableName Name of variable.
@param[in] VendorGuid Guid of variable.
@param[in] Data Data pointer.
@param[in] DataSize Size of Data.
@param[in] Attributes Attribute value of the variable.
@retval EFI_SUCCESS The update operation is success.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_WRITE_PROTECTED Variable is write-protected.
@retval EFI_OUT_OF_RESOURCES There is not enough resource.
**/
EFI_STATUS
AuthServiceInternalUpdateVariable (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN VOID *Data,
IN UINTN DataSize,
IN UINT32 Attributes
)
{
AUTH_VARIABLE_INFO AuthVariableInfo;
ZeroMem (&AuthVariableInfo, sizeof (AuthVariableInfo));
AuthVariableInfo.VariableName = VariableName;
AuthVariableInfo.VendorGuid = VendorGuid;
AuthVariableInfo.Data = Data;
AuthVariableInfo.DataSize = DataSize;
AuthVariableInfo.Attributes = Attributes;
return mAuthVarLibContextIn->UpdateVariable (
&AuthVariableInfo
);
}
/**
Update the variable region with Variable information.
@param[in] VariableName Name of variable.
@param[in] VendorGuid Guid of variable.
@param[in] Data Data pointer.
@param[in] DataSize Size of Data.
@param[in] Attributes Attribute value of the variable.
@param[in] KeyIndex Index of associated public key.
@param[in] MonotonicCount Value of associated monotonic count.
@retval EFI_SUCCESS The update operation is success.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_WRITE_PROTECTED Variable is write-protected.
@retval EFI_OUT_OF_RESOURCES There is not enough resource.
**/
EFI_STATUS
AuthServiceInternalUpdateVariableWithMonotonicCount (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN VOID *Data,
IN UINTN DataSize,
IN UINT32 Attributes,
IN UINT32 KeyIndex,
IN UINT64 MonotonicCount
)
{
AUTH_VARIABLE_INFO AuthVariableInfo;
ZeroMem (&AuthVariableInfo, sizeof (AuthVariableInfo));
AuthVariableInfo.VariableName = VariableName;
AuthVariableInfo.VendorGuid = VendorGuid;
AuthVariableInfo.Data = Data;
AuthVariableInfo.DataSize = DataSize;
AuthVariableInfo.Attributes = Attributes;
AuthVariableInfo.PubKeyIndex = KeyIndex;
AuthVariableInfo.MonotonicCount = MonotonicCount;
return mAuthVarLibContextIn->UpdateVariable (
&AuthVariableInfo
);
}
/**
Update the variable region with Variable information.
@param[in] VariableName Name of variable.
@param[in] VendorGuid Guid of variable.
@param[in] Data Data pointer.
@param[in] DataSize Size of Data.
@param[in] Attributes Attribute value of the variable.
@param[in] TimeStamp Value of associated TimeStamp.
@retval EFI_SUCCESS The update operation is success.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_WRITE_PROTECTED Variable is write-protected.
@retval EFI_OUT_OF_RESOURCES There is not enough resource.
**/
EFI_STATUS
AuthServiceInternalUpdateVariableWithTimeStamp (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN VOID *Data,
IN UINTN DataSize,
IN UINT32 Attributes,
IN EFI_TIME *TimeStamp
)
{
EFI_STATUS FindStatus;
VOID *OrgData;
UINTN OrgDataSize;
AUTH_VARIABLE_INFO AuthVariableInfo;
FindStatus = AuthServiceInternalFindVariable (
VariableName,
VendorGuid,
&OrgData,
&OrgDataSize
);
//
// EFI_VARIABLE_APPEND_WRITE attribute only effects for existing variable
//
if (!EFI_ERROR (FindStatus) && ((Attributes & EFI_VARIABLE_APPEND_WRITE) != 0)) {
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))) ||
(CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) && (StrCmp (VariableName, EFI_KEY_EXCHANGE_KEY_NAME) == 0))) {
//
// For variables with formatted as EFI_SIGNATURE_LIST, the driver shall not perform an append of
// EFI_SIGNATURE_DATA values that are already part of the existing variable value.
//
FilterSignatureList (
OrgData,
OrgDataSize,
Data,
&DataSize
);
}
}
ZeroMem (&AuthVariableInfo, sizeof (AuthVariableInfo));
AuthVariableInfo.VariableName = VariableName;
AuthVariableInfo.VendorGuid = VendorGuid;
AuthVariableInfo.Data = Data;
AuthVariableInfo.DataSize = DataSize;
AuthVariableInfo.Attributes = Attributes;
AuthVariableInfo.TimeStamp = TimeStamp;
return mAuthVarLibContextIn->UpdateVariable (
&AuthVariableInfo
);
}
/**
Determine whether this operation needs a physical present user.
@param[in] VariableName Name of the Variable.
@param[in] VendorGuid GUID of the Variable.
@retval TRUE This variable is protected, only a physical present user could set this variable.
@retval FALSE This variable is not protected.
**/
BOOLEAN
NeedPhysicallyPresent(
IN CHAR16 *VariableName,
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;
}
return FALSE;
}
/**
Determine whether the platform is operating in Custom Secure Boot mode.
@retval TRUE The platform is operating in Custom mode.
@retval FALSE The platform is operating in Standard mode.
**/
BOOLEAN
InCustomMode (
VOID
)
{
EFI_STATUS Status;
VOID *Data;
UINTN DataSize;
Status = AuthServiceInternalFindVariable (EFI_CUSTOM_MODE_NAME, &gEfiCustomModeEnableGuid, &Data, &DataSize);
if (!EFI_ERROR (Status) && (*(UINT8 *) Data == CUSTOM_SECURE_BOOT_MODE)) {
return TRUE;
}
return FALSE;
}
/**
Get available public key index.
@param[in] PubKey Pointer to Public Key data.
@return Public key index, 0 if no any public key index available.
**/
UINT32
GetAvailableKeyIndex (
IN UINT8 *PubKey
)
{
EFI_STATUS Status;
UINT8 *Data;
UINTN DataSize;
UINT8 *Ptr;
UINT32 Index;
BOOLEAN IsFound;
EFI_GUID VendorGuid;
CHAR16 Name[1];
AUTH_VARIABLE_INFO AuthVariableInfo;
UINT32 KeyIndex;
Status = AuthServiceInternalFindVariable (
AUTHVAR_KEYDB_NAME,
&gEfiAuthenticatedVariableGuid,
(VOID **) &Data,
&DataSize
);
if (EFI_ERROR (Status)) {
DEBUG ((EFI_D_ERROR, "Get public key database variable failure, Status = %r\n", Status));
return 0;
}
if (mPubKeyNumber == mMaxKeyNumber) {
Name[0] = 0;
AuthVariableInfo.VariableName = Name;
ZeroMem (&VendorGuid, sizeof (VendorGuid));
AuthVariableInfo.VendorGuid = &VendorGuid;
mPubKeyNumber = 0;
//
// Collect valid key data.
//
do {
Status = mAuthVarLibContextIn->FindNextVariable (AuthVariableInfo.VariableName, AuthVariableInfo.VendorGuid, &AuthVariableInfo);
if (!EFI_ERROR (Status)) {
if (AuthVariableInfo.PubKeyIndex != 0) {
for (Ptr = Data; Ptr < (Data + DataSize); Ptr += sizeof (AUTHVAR_KEY_DB_DATA)) {
if (ReadUnaligned32 (&(((AUTHVAR_KEY_DB_DATA *) Ptr)->KeyIndex)) == AuthVariableInfo.PubKeyIndex) {
//
// Check if the key data has been collected.
//
for (Index = 0; Index < mPubKeyNumber; Index++) {
if (ReadUnaligned32 (&(((AUTHVAR_KEY_DB_DATA *) mPubKeyStore + Index)->KeyIndex)) == AuthVariableInfo.PubKeyIndex) {
break;
}
}
if (Index == mPubKeyNumber) {
//
// New key data.
//
CopyMem ((AUTHVAR_KEY_DB_DATA *) mPubKeyStore + mPubKeyNumber, Ptr, sizeof (AUTHVAR_KEY_DB_DATA));
mPubKeyNumber++;
}
break;
}
}
}
}
} while (Status != EFI_NOT_FOUND);
//
// No available space to add new public key.
//
if (mPubKeyNumber == mMaxKeyNumber) {
return 0;
}
}
//
// Find available public key index.
//
for (KeyIndex = 1; KeyIndex <= mMaxKeyNumber; KeyIndex++) {
IsFound = FALSE;
for (Ptr = mPubKeyStore; Ptr < (mPubKeyStore + mPubKeyNumber * sizeof (AUTHVAR_KEY_DB_DATA)); Ptr += sizeof (AUTHVAR_KEY_DB_DATA)) {
if (ReadUnaligned32 (&(((AUTHVAR_KEY_DB_DATA *) Ptr)->KeyIndex)) == KeyIndex) {
IsFound = TRUE;
break;
}
}
if (!IsFound) {
break;
}
}
return KeyIndex;
}
/**
Add public key in store and return its index.
@param[in] PubKey Input pointer to Public Key data.
@param[in] VariableDataEntry The variable data entry.
@return Index of new added public key.
**/
UINT32
AddPubKeyInStore (
IN UINT8 *PubKey,
IN VARIABLE_ENTRY_CONSISTENCY *VariableDataEntry
)
{
EFI_STATUS Status;
UINT32 Index;
VARIABLE_ENTRY_CONSISTENCY PublicKeyEntry;
UINT32 Attributes;
UINT32 KeyIndex;
if (PubKey == NULL) {
return 0;
}
//
// Check whether the public key entry does exist.
//
for (Index = 0; Index < mPubKeyNumber; Index++) {
if (CompareMem (((AUTHVAR_KEY_DB_DATA *) mPubKeyStore + Index)->KeyData, PubKey, EFI_CERT_TYPE_RSA2048_SIZE) == 0) {
return ReadUnaligned32 (&(((AUTHVAR_KEY_DB_DATA *) mPubKeyStore + Index)->KeyIndex));
}
}
KeyIndex = GetAvailableKeyIndex (PubKey);
if (KeyIndex == 0) {
return 0;
}
//
// Check the variable space for both public key and variable data.
//
PublicKeyEntry.VariableSize = (mPubKeyNumber + 1) * sizeof (AUTHVAR_KEY_DB_DATA);
PublicKeyEntry.Guid = &gEfiAuthenticatedVariableGuid;
PublicKeyEntry.Name = AUTHVAR_KEYDB_NAME;
Attributes = VARIABLE_ATTRIBUTE_NV_BS_RT | EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS;
if (!mAuthVarLibContextIn->CheckRemainingSpaceForConsistency (Attributes, &PublicKeyEntry, VariableDataEntry, NULL)) {
//
// No enough variable space.
//
return 0;
}
WriteUnaligned32 (&(((AUTHVAR_KEY_DB_DATA *) mPubKeyStore + mPubKeyNumber)->KeyIndex), KeyIndex);
CopyMem (((AUTHVAR_KEY_DB_DATA *) mPubKeyStore + mPubKeyNumber)->KeyData, PubKey, EFI_CERT_TYPE_RSA2048_SIZE);
mPubKeyNumber++;
//
// Update public key database variable.
//
Status = AuthServiceInternalUpdateVariable (
AUTHVAR_KEYDB_NAME,
&gEfiAuthenticatedVariableGuid,
mPubKeyStore,
mPubKeyNumber * sizeof (AUTHVAR_KEY_DB_DATA),
Attributes
);
if (EFI_ERROR (Status)) {
DEBUG ((EFI_D_ERROR, "Update public key database variable failure, Status = %r\n", Status));
return 0;
}
return KeyIndex;
}
/**
Verify data payload with AuthInfo in EFI_CERT_TYPE_RSA2048_SHA256_GUID type.
Follow the steps in UEFI2.2.
Caution: This function may receive untrusted input.
This function may be invoked in SMM mode, and datasize and data are external input.
This function will do basic validation, before parse the data.
This function will parse the authentication carefully to avoid security issues, like
buffer overflow, integer overflow.
@param[in] Data Pointer to data with AuthInfo.
@param[in] DataSize Size of Data.
@param[in] PubKey Public key used for verification.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_SECURITY_VIOLATION If authentication failed.
@retval EFI_SUCCESS Authentication successful.
**/
EFI_STATUS
VerifyCounterBasedPayload (
IN UINT8 *Data,
IN UINTN DataSize,
IN UINT8 *PubKey
)
{
BOOLEAN Status;
EFI_VARIABLE_AUTHENTICATION *CertData;
EFI_CERT_BLOCK_RSA_2048_SHA256 *CertBlock;
UINT8 Digest[SHA256_DIGEST_SIZE];
VOID *Rsa;
UINTN PayloadSize;
PayloadSize = DataSize - AUTHINFO_SIZE;
Rsa = NULL;
CertData = NULL;
CertBlock = NULL;
if (Data == NULL || PubKey == NULL) {
return EFI_INVALID_PARAMETER;
}
CertData = (EFI_VARIABLE_AUTHENTICATION *) Data;
CertBlock = (EFI_CERT_BLOCK_RSA_2048_SHA256 *) (CertData->AuthInfo.CertData);
//
// wCertificateType should be WIN_CERT_TYPE_EFI_GUID.
// Cert type should be EFI_CERT_TYPE_RSA2048_SHA256_GUID.
//
if ((CertData->AuthInfo.Hdr.wCertificateType != WIN_CERT_TYPE_EFI_GUID) ||
!CompareGuid (&CertData->AuthInfo.CertType, &gEfiCertTypeRsa2048Sha256Guid)) {
//
// Invalid AuthInfo type, return EFI_SECURITY_VIOLATION.
//
return EFI_SECURITY_VIOLATION;
}
//
// Hash data payload with SHA256.
//
ZeroMem (Digest, SHA256_DIGEST_SIZE);
Status = Sha256Init (mHashCtx);
if (!Status) {
goto Done;
}
Status = Sha256Update (mHashCtx, Data + AUTHINFO_SIZE, PayloadSize);
if (!Status) {
goto Done;
}
//
// Hash Size.
//
Status = Sha256Update (mHashCtx, &PayloadSize, sizeof (UINTN));
if (!Status) {
goto Done;
}
//
// Hash Monotonic Count.
//
Status = Sha256Update (mHashCtx, &CertData->MonotonicCount, sizeof (UINT64));
if (!Status) {
goto Done;
}
Status = Sha256Final (mHashCtx, Digest);
if (!Status) {
goto Done;
}
//
// Generate & Initialize RSA Context.
//
Rsa = RsaNew ();
ASSERT (Rsa != NULL);
//
// Set RSA Key Components.
// NOTE: Only N and E are needed to be set as RSA public key for signature verification.
//
Status = RsaSetKey (Rsa, RsaKeyN, PubKey, EFI_CERT_TYPE_RSA2048_SIZE);
if (!Status) {
goto Done;
}
Status = RsaSetKey (Rsa, RsaKeyE, mRsaE, sizeof (mRsaE));
if (!Status) {
goto Done;
}
//
// Verify the signature.
//
Status = RsaPkcs1Verify (
Rsa,
Digest,
SHA256_DIGEST_SIZE,
CertBlock->Signature,
EFI_CERT_TYPE_RSA2048_SHA256_SIZE
);
Done:
if (Rsa != NULL) {
RsaFree (Rsa);
}
if (Status) {
return EFI_SUCCESS;
} else {
return EFI_SECURITY_VIOLATION;
}
}
/**
Update platform mode.
@param[in] Mode SETUP_MODE or USER_MODE.
@return EFI_INVALID_PARAMETER Invalid parameter.
@return EFI_SUCCESS Update platform mode successfully.
**/
EFI_STATUS
UpdatePlatformMode (
IN UINT32 Mode
)
{
EFI_STATUS Status;
VOID *Data;
UINTN DataSize;
UINT8 SecureBootMode;
UINT8 SecureBootEnable;
UINTN VariableDataSize;
Status = AuthServiceInternalFindVariable (
EFI_SETUP_MODE_NAME,
&gEfiGlobalVariableGuid,
&Data,
&DataSize
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Update the value of SetupMode variable by a simple mem copy, this could avoid possible
// variable storage reclaim at runtime.
//
mPlatformMode = (UINT8) Mode;
CopyMem (Data, &mPlatformMode, sizeof(UINT8));
if (mAuthVarLibContextIn->AtRuntime ()) {
//
// SecureBoot Variable indicates whether the platform firmware is operating
// in Secure boot mode (1) or not (0), so we should not change SecureBoot
// Variable in runtime.
//
return Status;
}
//
// Check "SecureBoot" variable's existence.
// If it doesn't exist, firmware has no capability to perform driver signing verification,
// then set "SecureBoot" to 0.
//
Status = AuthServiceInternalFindVariable (
EFI_SECURE_BOOT_MODE_NAME,
&gEfiGlobalVariableGuid,
&Data,
&DataSize
);
//
// If "SecureBoot" variable exists, then check "SetupMode" variable update.
// If "SetupMode" variable is USER_MODE, "SecureBoot" variable is set to 1.
// If "SetupMode" variable is SETUP_MODE, "SecureBoot" variable is set to 0.
//
if (EFI_ERROR (Status)) {
SecureBootMode = SECURE_BOOT_MODE_DISABLE;
} else {
if (mPlatformMode == USER_MODE) {
SecureBootMode = SECURE_BOOT_MODE_ENABLE;
} else if (mPlatformMode == SETUP_MODE) {
SecureBootMode = SECURE_BOOT_MODE_DISABLE;
} else {
return EFI_NOT_FOUND;
}
}
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;
}
//
// Check "SecureBootEnable" variable's existence. It can enable/disable secure boot feature.
//
Status = AuthServiceInternalFindVariable (
EFI_SECURE_BOOT_ENABLE_NAME,
&gEfiSecureBootEnableDisableGuid,
&Data,
&DataSize
);
if (SecureBootMode == SECURE_BOOT_MODE_ENABLE) {
//
// Create the "SecureBootEnable" variable as secure boot is enabled.
//
SecureBootEnable = SECURE_BOOT_ENABLE;
VariableDataSize = sizeof (SecureBootEnable);
} else {
//
// Delete the "SecureBootEnable" variable if this variable exist as "SecureBoot"
// variable is not in secure boot state.
//
if (EFI_ERROR (Status)) {
return EFI_SUCCESS;
}
SecureBootEnable = SECURE_BOOT_DISABLE;
VariableDataSize = 0;
}
Status = AuthServiceInternalUpdateVariable (
EFI_SECURE_BOOT_ENABLE_NAME,
&gEfiSecureBootEnableDisableGuid,
&SecureBootEnable,
VariableDataSize,
EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS
);
return Status;
}
/**
Check input data form to make sure it is a valid EFI_SIGNATURE_LIST for PK/KEK/db/dbx/dbt variable.
@param[in] VariableName Name of Variable to be check.
@param[in] VendorGuid Variable vendor GUID.
@param[in] Data Point to the variable data to be checked.
@param[in] DataSize Size of Data.
@return EFI_INVALID_PARAMETER Invalid signature list format.
@return EFI_SUCCESS Passed signature list format check successfully.
**/
EFI_STATUS
CheckSignatureListFormat(
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN VOID *Data,
IN UINTN DataSize
)
{
EFI_SIGNATURE_LIST *SigList;
UINTN SigDataSize;
UINT32 Index;
UINT32 SigCount;
BOOLEAN IsPk;
VOID *RsaContext;
EFI_SIGNATURE_DATA *CertData;
UINTN CertLen;
if (DataSize == 0) {
return EFI_SUCCESS;
}
ASSERT (VariableName != NULL && VendorGuid != NULL && Data != NULL);
if (CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) && (StrCmp (VariableName, EFI_PLATFORM_KEY_NAME) == 0)){
IsPk = TRUE;
} else if ((CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) && (StrCmp (VariableName, EFI_KEY_EXCHANGE_KEY_NAME) == 0)) ||
(CompareGuid (VendorGuid, &gEfiImageSecurityDatabaseGuid) &&
((StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) || (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE1) == 0) ||
(StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE2) == 0)))) {
IsPk = FALSE;
} else {
return EFI_SUCCESS;
}
SigCount = 0;
SigList = (EFI_SIGNATURE_LIST *) Data;
SigDataSize = DataSize;
RsaContext = NULL;
//
// Walk throuth the input signature list and check the data format.
// If any signature is incorrectly formed, the whole check will fail.
//
while ((SigDataSize > 0) && (SigDataSize >= SigList->SignatureListSize)) {
for (Index = 0; Index < (sizeof (mSupportSigItem) / sizeof (EFI_SIGNATURE_ITEM)); Index++ ) {
if (CompareGuid (&SigList->SignatureType, &mSupportSigItem[Index].SigType)) {
//
// The value of SignatureSize should always be 16 (size of SignatureOwner
// component) add the data length according to signature type.
//
if (mSupportSigItem[Index].SigDataSize != ((UINT32) ~0) &&
(SigList->SignatureSize - sizeof (EFI_GUID)) != mSupportSigItem[Index].SigDataSize) {
return EFI_INVALID_PARAMETER;
}
if (mSupportSigItem[Index].SigHeaderSize != ((UINT32) ~0) &&
SigList->SignatureHeaderSize != mSupportSigItem[Index].SigHeaderSize) {
return EFI_INVALID_PARAMETER;
}
break;
}
}
if (Index == (sizeof (mSupportSigItem) / sizeof (EFI_SIGNATURE_ITEM))) {
//
// Undefined signature type.
//
return EFI_INVALID_PARAMETER;
}
if (CompareGuid (&SigList->SignatureType, &gEfiCertX509Guid)) {
//
// Try to retrieve the RSA public key from the X.509 certificate.
// If this operation fails, it's not a valid certificate.
//
RsaContext = RsaNew ();
if (RsaContext == NULL) {
return EFI_INVALID_PARAMETER;
}
CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) SigList + sizeof (EFI_SIGNATURE_LIST) + SigList->SignatureHeaderSize);
CertLen = SigList->SignatureSize - sizeof (EFI_GUID);
if (!RsaGetPublicKeyFromX509 (CertData->SignatureData, CertLen, &RsaContext)) {
RsaFree (RsaContext);
return EFI_INVALID_PARAMETER;
}
RsaFree (RsaContext);
}
if ((SigList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - SigList->SignatureHeaderSize) % SigList->SignatureSize != 0) {
return EFI_INVALID_PARAMETER;
}
SigCount += (SigList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - SigList->SignatureHeaderSize) / SigList->SignatureSize;
SigDataSize -= SigList->SignatureListSize;
SigList = (EFI_SIGNATURE_LIST *) ((UINT8 *) SigList + SigList->SignatureListSize);
}
if (((UINTN) SigList - (UINTN) Data) != DataSize) {
return EFI_INVALID_PARAMETER;
}
if (IsPk && SigCount > 1) {
return EFI_INVALID_PARAMETER;
}
return EFI_SUCCESS;
}
/**
Update "VendorKeys" variable to record the out of band secure boot key modification.
@return EFI_SUCCESS Variable is updated successfully.
@return Others Failed to update variable.
**/
EFI_STATUS
VendorKeyIsModified (
VOID
)
{
EFI_STATUS Status;
if (mVendorKeyState == VENDOR_KEYS_MODIFIED) {
return EFI_SUCCESS;
}
mVendorKeyState = VENDOR_KEYS_MODIFIED;
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;
}
return AuthServiceInternalUpdateVariable (
EFI_VENDOR_KEYS_VARIABLE_NAME,
&gEfiGlobalVariableGuid,
&mVendorKeyState,
sizeof (UINT8),
EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS
);
}
/**
Process variable with platform key for verification.
Caution: This function may receive untrusted input.
This function may be invoked in SMM mode, and datasize and data are external input.
This function will do basic validation, before parse the data.
This function will parse the authentication carefully to avoid security issues, like
buffer overflow, integer overflow.
This function will check attribute carefully to avoid authentication bypass.
@param[in] VariableName Name of Variable to be found.
@param[in] VendorGuid Variable vendor GUID.
@param[in] Data Data pointer.
@param[in] DataSize Size of Data found. If size is less than the
data, this value contains the required size.
@param[in] Attributes Attribute value of the variable
@param[in] IsPk Indicate whether it is to process pk.
@return EFI_INVALID_PARAMETER Invalid parameter.
@return EFI_SECURITY_VIOLATION The variable does NOT pass the validation.
check carried out by the firmware.
@return EFI_SUCCESS Variable passed validation successfully.
**/
EFI_STATUS
ProcessVarWithPk (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN VOID *Data,
IN UINTN DataSize,
IN UINT32 Attributes OPTIONAL,
IN BOOLEAN IsPk
)
{
EFI_STATUS Status;
BOOLEAN Del;
UINT8 *Payload;
UINTN PayloadSize;
if ((Attributes & EFI_VARIABLE_NON_VOLATILE) == 0 ||
(Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) == 0) {
//
// PK, KEK and db/dbx/dbt should set EFI_VARIABLE_NON_VOLATILE attribute and should be a time-based
// authenticated variable.
//
return EFI_INVALID_PARAMETER;
}
//
// Init state of Del. State may change due to secure check
//
Del = FALSE;
if ((InCustomMode() && UserPhysicalPresent()) || (mPlatformMode == SETUP_MODE && !IsPk)) {
Payload = (UINT8 *) Data + AUTHINFO2_SIZE (Data);
PayloadSize = DataSize - AUTHINFO2_SIZE (Data);
if (PayloadSize == 0) {
Del = TRUE;
}
Status = CheckSignatureListFormat(VariableName, VendorGuid, Payload, PayloadSize);
if (EFI_ERROR (Status)) {
return Status;
}
Status = AuthServiceInternalUpdateVariableWithTimeStamp (
VariableName,
VendorGuid,
Payload,
PayloadSize,
Attributes,
&((EFI_VARIABLE_AUTHENTICATION_2 *) Data)->TimeStamp
);
if (EFI_ERROR(Status)) {
return Status;
}
if ((mPlatformMode != SETUP_MODE) || IsPk) {
Status = VendorKeyIsModified ();
}
} else if (mPlatformMode == USER_MODE) {
//
// Verify against X509 Cert in PK database.
//
Status = VerifyTimeBasedPayloadAndUpdate (
VariableName,
VendorGuid,
Data,
DataSize,
Attributes,
AuthVarTypePk,
&Del
);
} else {
//
// Verify against the certificate in data payload.
//
Status = VerifyTimeBasedPayloadAndUpdate (
VariableName,
VendorGuid,
Data,
DataSize,
Attributes,
AuthVarTypePayload,
&Del
);
}
if (!EFI_ERROR(Status) && IsPk) {
if (mPlatformMode == SETUP_MODE && !Del) {
//
// If enroll PK in setup mode, need change to user mode.
//
Status = UpdatePlatformMode (USER_MODE);
} else if (mPlatformMode == USER_MODE && Del){
//
// If delete PK in user mode, need change to setup mode.
//
Status = UpdatePlatformMode (SETUP_MODE);
}
}
return Status;
}
/**
Process variable with key exchange key for verification.
Caution: This function may receive untrusted input.
This function may be invoked in SMM mode, and datasize and data are external input.
This function will do basic validation, before parse the data.
This function will parse the authentication carefully to avoid security issues, like
buffer overflow, integer overflow.
This function will check attribute carefully to avoid authentication bypass.
@param[in] VariableName Name of Variable to be found.
@param[in] VendorGuid Variable vendor GUID.
@param[in] Data Data pointer.
@param[in] DataSize Size of Data found. If size is less than the
data, this value contains the required size.
@param[in] Attributes Attribute value of the variable.
@return EFI_INVALID_PARAMETER Invalid parameter.
@return EFI_SECURITY_VIOLATION The variable does NOT pass the validation
check carried out by the firmware.
@return EFI_SUCCESS Variable pass validation successfully.
**/
EFI_STATUS
ProcessVarWithKek (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN VOID *Data,
IN UINTN DataSize,
IN UINT32 Attributes OPTIONAL
)
{
EFI_STATUS Status;
UINT8 *Payload;
UINTN PayloadSize;
if ((Attributes & EFI_VARIABLE_NON_VOLATILE) == 0 ||
(Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) == 0) {
//
// DB, DBX and DBT should set EFI_VARIABLE_NON_VOLATILE attribute and should be a time-based
// authenticated variable.
//
return EFI_INVALID_PARAMETER;
}
Status = EFI_SUCCESS;
if (mPlatformMode == USER_MODE && !(InCustomMode() && UserPhysicalPresent())) {
//
// Time-based, verify against X509 Cert KEK.
//
return VerifyTimeBasedPayloadAndUpdate (
VariableName,
VendorGuid,
Data,
DataSize,
Attributes,
AuthVarTypeKek,
NULL
);
} else {
//
// If in setup mode or custom secure boot mode, no authentication needed.
//
Payload = (UINT8 *) Data + AUTHINFO2_SIZE (Data);
PayloadSize = DataSize - AUTHINFO2_SIZE (Data);
Status = CheckSignatureListFormat(VariableName, VendorGuid, Payload, PayloadSize);
if (EFI_ERROR (Status)) {
return Status;
}
Status = AuthServiceInternalUpdateVariableWithTimeStamp (
VariableName,
VendorGuid,
Payload,
PayloadSize,
Attributes,
&((EFI_VARIABLE_AUTHENTICATION_2 *) Data)->TimeStamp
);
if (EFI_ERROR (Status)) {
return Status;
}
if (mPlatformMode != SETUP_MODE) {
Status = VendorKeyIsModified ();
}
}
return Status;
}
/**
Check if it is to delete auth variable.
@param[in] OrgAttributes Original attribute value of the variable.
@param[in] Data Data pointer.
@param[in] DataSize Size of Data.
@param[in] Attributes Attribute value of the variable.
@retval TRUE It is to delete auth variable.
@retval FALSE It is not to delete auth variable.
**/
BOOLEAN
IsDeleteAuthVariable (
IN UINT32 OrgAttributes,
IN VOID *Data,
IN UINTN DataSize,
IN UINT32 Attributes
)
{
BOOLEAN Del;
UINTN PayloadSize;
Del = FALSE;
//
// To delete a variable created with the EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS
// or the EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS attribute,
// SetVariable must be used with attributes matching the existing variable
// and the DataSize set to the size of the AuthInfo descriptor.
//
if ((Attributes == OrgAttributes) &&
((Attributes & (EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) != 0)) {
if ((Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0) {
PayloadSize = DataSize - AUTHINFO2_SIZE (Data);
if (PayloadSize == 0) {
Del = TRUE;
}
} else {
PayloadSize = DataSize - AUTHINFO_SIZE;
if (PayloadSize == 0) {
Del = TRUE;
}
}
}
return Del;
}
/**
Process variable with EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS/EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set
Caution: This function may receive untrusted input.
This function may be invoked in SMM mode, and datasize and data are external input.
This function will do basic validation, before parse the data.
This function will parse the authentication carefully to avoid security issues, like
buffer overflow, integer overflow.
This function will check attribute carefully to avoid authentication bypass.
@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.
@return EFI_INVALID_PARAMETER Invalid parameter.
@return EFI_WRITE_PROTECTED Variable is write-protected and needs authentication with
EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS set.
@return EFI_OUT_OF_RESOURCES The Database to save the public key is full.
@return EFI_SECURITY_VIOLATION The variable is with EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS
set, but the AuthInfo does NOT pass the validation
check carried out by the firmware.
@return EFI_SUCCESS Variable is not write-protected or pass validation successfully.
**/
EFI_STATUS
ProcessVariable (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN VOID *Data,
IN UINTN DataSize,
IN UINT32 Attributes
)
{
EFI_STATUS Status;
BOOLEAN IsDeletion;
BOOLEAN IsFirstTime;
UINT8 *PubKey;
EFI_VARIABLE_AUTHENTICATION *CertData;
EFI_CERT_BLOCK_RSA_2048_SHA256 *CertBlock;
UINT32 KeyIndex;
UINT64 MonotonicCount;
VARIABLE_ENTRY_CONSISTENCY VariableDataEntry;
UINT32 Index;
AUTH_VARIABLE_INFO OrgVariableInfo;
KeyIndex = 0;
CertData = NULL;
CertBlock = NULL;
PubKey = NULL;
IsDeletion = FALSE;
Status = EFI_SUCCESS;
ZeroMem (&OrgVariableInfo, sizeof (OrgVariableInfo));
Status = mAuthVarLibContextIn->FindVariable (
VariableName,
VendorGuid,
&OrgVariableInfo
);
if ((!EFI_ERROR (Status)) && IsDeleteAuthVariable (OrgVariableInfo.Attributes, Data, DataSize, Attributes) && UserPhysicalPresent()) {
//
// Allow the delete operation of common authenticated variable at user physical presence.
//
Status = AuthServiceInternalUpdateVariable (
VariableName,
VendorGuid,
NULL,
0,
0
);
if (!EFI_ERROR (Status) && ((Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0)) {
Status = DeleteCertsFromDb (VariableName, VendorGuid, Attributes);
}
return Status;
}
if (NeedPhysicallyPresent (VariableName, VendorGuid) && !UserPhysicalPresent()) {
//
// This variable is protected, only physical present user could modify its value.
//
return EFI_SECURITY_VIOLATION;
}
//
// A time-based authenticated variable and a count-based authenticated variable
// can't be updated by each other.
//
if (OrgVariableInfo.Data != NULL) {
if (((Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) != 0) &&
((OrgVariableInfo.Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0)) {
return EFI_SECURITY_VIOLATION;
}
if (((Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0) &&
((OrgVariableInfo.Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) != 0)) {
return EFI_SECURITY_VIOLATION;
}
}
//
// Process Time-based Authenticated variable.
//
if ((Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0) {
return VerifyTimeBasedPayloadAndUpdate (
VariableName,
VendorGuid,
Data,
DataSize,
Attributes,
AuthVarTypePriv,
NULL
);
}
//
// Determine if first time SetVariable with the EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS.
//
if ((Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) != 0) {
//
// Determine current operation type.
//
if (DataSize == AUTHINFO_SIZE) {
IsDeletion = TRUE;
}
//
// Determine whether this is the first time with EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS set.
//
if (OrgVariableInfo.Data == NULL) {
IsFirstTime = TRUE;
} else if ((OrgVariableInfo.Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) == 0) {
IsFirstTime = TRUE;
} else {
KeyIndex = OrgVariableInfo.PubKeyIndex;
IsFirstTime = FALSE;
}
} else if ((OrgVariableInfo.Data != NULL) &&
((OrgVariableInfo.Attributes & (EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) != 0)
) {
//
// If the variable is already write-protected, it always needs authentication before update.
//
return EFI_WRITE_PROTECTED;
} else {
//
// If without EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS, set and attributes collision.
// That means it is not authenticated variable, just update variable as usual.
//
Status = AuthServiceInternalUpdateVariable (VariableName, VendorGuid, Data, DataSize, Attributes);
return Status;
}
//
// Get PubKey and check Monotonic Count value corresponding to the variable.
//
CertData = (EFI_VARIABLE_AUTHENTICATION *) Data;
CertBlock = (EFI_CERT_BLOCK_RSA_2048_SHA256 *) (CertData->AuthInfo.CertData);
PubKey = CertBlock->PublicKey;
//
// Update Monotonic Count value.
//
MonotonicCount = CertData->MonotonicCount;
if (!IsFirstTime) {
//
// 2 cases need to check here
// 1. Internal PubKey variable. PubKeyIndex is always 0
// 2. Other counter-based AuthVariable. Check input PubKey.
//
if (KeyIndex == 0) {
return EFI_SECURITY_VIOLATION;
}
for (Index = 0; Index < mPubKeyNumber; Index++) {
if (ReadUnaligned32 (&(((AUTHVAR_KEY_DB_DATA *) mPubKeyStore + Index)->KeyIndex)) == KeyIndex) {
if (CompareMem (((AUTHVAR_KEY_DB_DATA *) mPubKeyStore + Index)->KeyData, PubKey, EFI_CERT_TYPE_RSA2048_SIZE) == 0) {
break;
} else {
return EFI_SECURITY_VIOLATION;
}
}
}
if (Index == mPubKeyNumber) {
return EFI_SECURITY_VIOLATION;
}
//
// Compare the current monotonic count and ensure that it is greater than the last SetVariable
// operation with the EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS attribute set.
//
if (MonotonicCount <= OrgVariableInfo.MonotonicCount) {
//
// Monotonic count check fail, suspicious replay attack, return EFI_SECURITY_VIOLATION.
//
return EFI_SECURITY_VIOLATION;
}
}
//
// Verify the certificate in Data payload.
//
Status = VerifyCounterBasedPayload (Data, DataSize, PubKey);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Now, the signature has been verified!
//
if (IsFirstTime && !IsDeletion) {
VariableDataEntry.VariableSize = DataSize - AUTHINFO_SIZE;
VariableDataEntry.Guid = VendorGuid;
VariableDataEntry.Name = VariableName;
//
// Update public key database variable if need.
//
KeyIndex = AddPubKeyInStore (PubKey, &VariableDataEntry);
if (KeyIndex == 0) {
return EFI_OUT_OF_RESOURCES;
}
}
//
// Verification pass.
//
return AuthServiceInternalUpdateVariableWithMonotonicCount (VariableName, VendorGuid, (UINT8*)Data + AUTHINFO_SIZE, DataSize - AUTHINFO_SIZE, Attributes, KeyIndex, MonotonicCount);
}
/**
Filter out the duplicated EFI_SIGNATURE_DATA from the new data by comparing to the original data.
@param[in] Data Pointer to original EFI_SIGNATURE_LIST.
@param[in] DataSize Size of Data buffer.
@param[in, out] NewData Pointer to new EFI_SIGNATURE_LIST.
@param[in, out] NewDataSize Size of NewData buffer.
**/
EFI_STATUS
FilterSignatureList (
IN VOID *Data,
IN UINTN DataSize,
IN OUT VOID *NewData,
IN OUT UINTN *NewDataSize
)
{
EFI_SIGNATURE_LIST *CertList;
EFI_SIGNATURE_DATA *Cert;
UINTN CertCount;
EFI_SIGNATURE_LIST *NewCertList;
EFI_SIGNATURE_DATA *NewCert;
UINTN NewCertCount;
UINTN Index;
UINTN Index2;
UINTN Size;
UINT8 *Tail;
UINTN CopiedCount;
UINTN SignatureListSize;
BOOLEAN IsNewCert;
UINT8 *TempData;
UINTN TempDataSize;
EFI_STATUS Status;
if (*NewDataSize == 0) {
return EFI_SUCCESS;
}
TempDataSize = *NewDataSize;
Status = mAuthVarLibContextIn->GetScratchBuffer (&TempDataSize, (VOID **) &TempData);
if (EFI_ERROR (Status)) {
return EFI_OUT_OF_RESOURCES;
}
Tail = TempData;
NewCertList = (EFI_SIGNATURE_LIST *) NewData;
while ((*NewDataSize > 0) && (*NewDataSize >= NewCertList->SignatureListSize)) {
NewCert = (EFI_SIGNATURE_DATA *) ((UINT8 *) NewCertList + sizeof (EFI_SIGNATURE_LIST) + NewCertList->SignatureHeaderSize);
NewCertCount = (NewCertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - NewCertList->SignatureHeaderSize) / NewCertList->SignatureSize;
CopiedCount = 0;
for (Index = 0; Index < NewCertCount; Index++) {
IsNewCert = TRUE;
Size = DataSize;
CertList = (EFI_SIGNATURE_LIST *) Data;
while ((Size > 0) && (Size >= CertList->SignatureListSize)) {
if (CompareGuid (&CertList->SignatureType, &NewCertList->SignatureType) &&
(CertList->SignatureSize == NewCertList->SignatureSize)) {
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
for (Index2 = 0; Index2 < CertCount; Index2++) {
//
// Iterate each Signature Data in this Signature List.
//
if (CompareMem (NewCert, Cert, CertList->SignatureSize) == 0) {
IsNewCert = FALSE;
break;
}
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
}
}
if (!IsNewCert) {
break;
}
Size -= CertList->SignatureListSize;
CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
}
if (IsNewCert) {
//
// New EFI_SIGNATURE_DATA, keep it.
//
if (CopiedCount == 0) {
//
// Copy EFI_SIGNATURE_LIST header for only once.
//
CopyMem (Tail, NewCertList, sizeof (EFI_SIGNATURE_LIST) + NewCertList->SignatureHeaderSize);
Tail = Tail + sizeof (EFI_SIGNATURE_LIST) + NewCertList->SignatureHeaderSize;
}
CopyMem (Tail, NewCert, NewCertList->SignatureSize);
Tail += NewCertList->SignatureSize;
CopiedCount++;
}
NewCert = (EFI_SIGNATURE_DATA *) ((UINT8 *) NewCert + NewCertList->SignatureSize);
}
//
// Update SignatureListSize in the kept EFI_SIGNATURE_LIST.
//
if (CopiedCount != 0) {
SignatureListSize = sizeof (EFI_SIGNATURE_LIST) + NewCertList->SignatureHeaderSize + (CopiedCount * NewCertList->SignatureSize);
CertList = (EFI_SIGNATURE_LIST *) (Tail - SignatureListSize);
CertList->SignatureListSize = (UINT32) SignatureListSize;
}
*NewDataSize -= NewCertList->SignatureListSize;
NewCertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) NewCertList + NewCertList->SignatureListSize);
}
TempDataSize = (Tail - (UINT8 *) TempData);
CopyMem (NewData, TempData, TempDataSize);
*NewDataSize = TempDataSize;
return EFI_SUCCESS;
}
/**
Compare two EFI_TIME data.
@param FirstTime A pointer to the first EFI_TIME data.
@param SecondTime A pointer to the second EFI_TIME data.
@retval TRUE The FirstTime is not later than the SecondTime.
@retval FALSE The FirstTime is later than the SecondTime.
**/
BOOLEAN
AuthServiceInternalCompareTimeStamp (
IN EFI_TIME *FirstTime,
IN EFI_TIME *SecondTime
)
{
if (FirstTime->Year != SecondTime->Year) {
return (BOOLEAN) (FirstTime->Year < SecondTime->Year);
} else if (FirstTime->Month != SecondTime->Month) {
return (BOOLEAN) (FirstTime->Month < SecondTime->Month);
} else if (FirstTime->Day != SecondTime->Day) {
return (BOOLEAN) (FirstTime->Day < SecondTime->Day);
} else if (FirstTime->Hour != SecondTime->Hour) {
return (BOOLEAN) (FirstTime->Hour < SecondTime->Hour);
} else if (FirstTime->Minute != SecondTime->Minute) {
return (BOOLEAN) (FirstTime->Minute < SecondTime->Minute);
}
return (BOOLEAN) (FirstTime->Second <= SecondTime->Second);
}
/**
Find matching signer's certificates for common authenticated variable
by corresponding VariableName and VendorGuid from "certdb" or "certdbv".
The data format of "certdb" or "certdbv":
//
// UINT32 CertDbListSize;
// /// AUTH_CERT_DB_DATA Certs1[];
// /// AUTH_CERT_DB_DATA Certs2[];
// /// ...
// /// AUTH_CERT_DB_DATA Certsn[];
//
@param[in] VariableName Name of authenticated Variable.
@param[in] VendorGuid Vendor GUID of authenticated Variable.
@param[in] Data Pointer to variable "certdb" or "certdbv".
@param[in] DataSize Size of variable "certdb" or "certdbv".
@param[out] CertOffset Offset of matching CertData, from starting of Data.
@param[out] CertDataSize Length of CertData in bytes.
@param[out] CertNodeOffset Offset of matching AUTH_CERT_DB_DATA , from
starting of Data.
@param[out] CertNodeSize Length of AUTH_CERT_DB_DATA in bytes.
@retval EFI_INVALID_PARAMETER Any input parameter is invalid.
@retval EFI_NOT_FOUND Fail to find matching certs.
@retval EFI_SUCCESS Find matching certs and output parameters.
**/
EFI_STATUS
FindCertsFromDb (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN UINT8 *Data,
IN UINTN DataSize,
OUT UINT32 *CertOffset, OPTIONAL
OUT UINT32 *CertDataSize, OPTIONAL
OUT UINT32 *CertNodeOffset,OPTIONAL
OUT UINT32 *CertNodeSize OPTIONAL
)
{
UINT32 Offset;
AUTH_CERT_DB_DATA *Ptr;
UINT32 CertSize;
UINT32 NameSize;
UINT32 NodeSize;
UINT32 CertDbListSize;
if ((VariableName == NULL) || (VendorGuid == NULL) || (Data == NULL)) {
return EFI_INVALID_PARAMETER;
}
//
// Check whether DataSize matches recorded CertDbListSize.
//
if (DataSize < sizeof (UINT32)) {
return EFI_INVALID_PARAMETER;
}
CertDbListSize = ReadUnaligned32 ((UINT32 *) Data);
if (CertDbListSize != (UINT32) DataSize) {
return EFI_INVALID_PARAMETER;
}
Offset = sizeof (UINT32);
//
// Get corresponding certificates by VendorGuid and VariableName.
//
while (Offset < (UINT32) DataSize) {
Ptr = (AUTH_CERT_DB_DATA *) (Data + Offset);
//
// Check whether VendorGuid matches.
//
if (CompareGuid (&Ptr->VendorGuid, VendorGuid)) {
NodeSize = ReadUnaligned32 (&Ptr->CertNodeSize);
NameSize = ReadUnaligned32 (&Ptr->NameSize);
CertSize = ReadUnaligned32 (&Ptr->CertDataSize);
if (NodeSize != sizeof (EFI_GUID) + sizeof (UINT32) * 3 + CertSize +
sizeof (CHAR16) * NameSize) {
return EFI_INVALID_PARAMETER;
}
Offset = Offset + sizeof (EFI_GUID) + sizeof (UINT32) * 3;
//
// Check whether VariableName matches.
//
if ((NameSize == StrLen (VariableName)) &&
(CompareMem (Data + Offset, VariableName, NameSize * sizeof (CHAR16)) == 0)) {
Offset = Offset + NameSize * sizeof (CHAR16);
if (CertOffset != NULL) {
*CertOffset = Offset;
}
if (CertDataSize != NULL) {
*CertDataSize = CertSize;
}
if (CertNodeOffset != NULL) {
*CertNodeOffset = (UINT32) ((UINT8 *) Ptr - Data);
}
if (CertNodeSize != NULL) {
*CertNodeSize = NodeSize;
}
return EFI_SUCCESS;
} else {
Offset = Offset + NameSize * sizeof (CHAR16) + CertSize;
}
} else {
NodeSize = ReadUnaligned32 (&Ptr->CertNodeSize);
Offset = Offset + NodeSize;
}
}
return EFI_NOT_FOUND;
}
/**
Retrieve signer's certificates for common authenticated variable
by corresponding VariableName and VendorGuid from "certdb"
or "certdbv" according to authenticated variable attributes.
@param[in] VariableName Name of authenticated Variable.
@param[in] VendorGuid Vendor GUID of authenticated Variable.
@param[in] Attributes Attributes of authenticated variable.
@param[out] CertData Pointer to signer's certificates.
@param[out] CertDataSize Length of CertData in bytes.
@retval EFI_INVALID_PARAMETER Any input parameter is invalid.
@retval EFI_NOT_FOUND Fail to find "certdb"/"certdbv" or matching certs.
@retval EFI_SUCCESS Get signer's certificates successfully.
**/
EFI_STATUS
GetCertsFromDb (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN UINT32 Attributes,
OUT UINT8 **CertData,
OUT UINT32 *CertDataSize
)
{
EFI_STATUS Status;
UINT8 *Data;
UINTN DataSize;
UINT32 CertOffset;
CHAR16 *DbName;
if ((VariableName == NULL) || (VendorGuid == NULL) || (CertData == NULL) || (CertDataSize == NULL)) {
return EFI_INVALID_PARAMETER;
}
if ((Attributes & EFI_VARIABLE_NON_VOLATILE) != 0) {
//
// Get variable "certdb".
//
DbName = EFI_CERT_DB_NAME;
} else {
//
// Get variable "certdbv".
//
DbName = EFI_CERT_DB_VOLATILE_NAME;
}
//
// Get variable "certdb" or "certdbv".
//
Status = AuthServiceInternalFindVariable (
DbName,
&gEfiCertDbGuid,
(VOID **) &Data,
&DataSize
);
if (EFI_ERROR (Status)) {
return Status;
}
if ((DataSize == 0) || (Data == NULL)) {
ASSERT (FALSE);
return EFI_NOT_FOUND;
}
Status = FindCertsFromDb (
VariableName,
VendorGuid,
Data,
DataSize,
&CertOffset,
CertDataSize,
NULL,
NULL
);
if (EFI_ERROR (Status)) {
return Status;
}
*CertData = Data + CertOffset;
return EFI_SUCCESS;
}
/**
Delete matching signer's certificates when deleting common authenticated
variable by corresponding VariableName and VendorGuid from "certdb" or
"certdbv" according to authenticated variable attributes.
@param[in] VariableName Name of authenticated Variable.
@param[in] VendorGuid Vendor GUID of authenticated Variable.
@param[in] Attributes Attributes of authenticated variable.
@retval EFI_INVALID_PARAMETER Any input parameter is invalid.
@retval EFI_NOT_FOUND Fail to find "certdb"/"certdbv" or matching certs.
@retval EFI_OUT_OF_RESOURCES The operation is failed due to lack of resources.
@retval EFI_SUCCESS The operation is completed successfully.
**/
EFI_STATUS
DeleteCertsFromDb (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN UINT32 Attributes
)
{
EFI_STATUS Status;
UINT8 *Data;
UINTN DataSize;
UINT32 VarAttr;
UINT32 CertNodeOffset;
UINT32 CertNodeSize;
UINT8 *NewCertDb;
UINT32 NewCertDbSize;
CHAR16 *DbName;
if ((VariableName == NULL) || (VendorGuid == NULL)) {
return EFI_INVALID_PARAMETER;
}
if ((Attributes & EFI_VARIABLE_NON_VOLATILE) != 0) {
//
// Get variable "certdb".
//
DbName = EFI_CERT_DB_NAME;
VarAttr = EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
} else {
//
// Get variable "certdbv".
//
DbName = EFI_CERT_DB_VOLATILE_NAME;
VarAttr = EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
}
Status = AuthServiceInternalFindVariable (
DbName,
&gEfiCertDbGuid,
(VOID **) &Data,
&DataSize
);
if (EFI_ERROR (Status)) {
return Status;
}
if ((DataSize == 0) || (Data == NULL)) {
ASSERT (FALSE);
return EFI_NOT_FOUND;
}
if (DataSize == sizeof (UINT32)) {
//
// There is no certs in "certdb" or "certdbv".
//
return EFI_SUCCESS;
}
//
// Get corresponding cert node from "certdb" or "certdbv".
//
Status = FindCertsFromDb (
VariableName,
VendorGuid,
Data,
DataSize,
NULL,
NULL,
&CertNodeOffset,
&CertNodeSize
);
if (EFI_ERROR (Status)) {
return Status;
}
if (DataSize < (CertNodeOffset + CertNodeSize)) {
return EFI_NOT_FOUND;
}
//
// Construct new data content of variable "certdb" or "certdbv".
//
NewCertDbSize = (UINT32) DataSize - CertNodeSize;
NewCertDb = (UINT8*) mCertDbStore;
//
// Copy the DB entries before deleting node.
//
CopyMem (NewCertDb, Data, CertNodeOffset);
//
// Update CertDbListSize.
//
CopyMem (NewCertDb, &NewCertDbSize, sizeof (UINT32));
//
// Copy the DB entries after deleting node.
//
if (DataSize > (CertNodeOffset + CertNodeSize)) {
CopyMem (
NewCertDb + CertNodeOffset,
Data + CertNodeOffset + CertNodeSize,
DataSize - CertNodeOffset - CertNodeSize
);
}
//
// Set "certdb" or "certdbv".
//
Status = AuthServiceInternalUpdateVariable (
DbName,
&gEfiCertDbGuid,
NewCertDb,
NewCertDbSize,
VarAttr
);
return Status;
}
/**
Insert signer's certificates for common authenticated variable with VariableName
and VendorGuid in AUTH_CERT_DB_DATA to "certdb" or "certdbv" according to
time based authenticated variable attributes.
@param[in] VariableName Name of authenticated Variable.
@param[in] VendorGuid Vendor GUID of authenticated Variable.
@param[in] Attributes Attributes of authenticated variable.
@param[in] CertData Pointer to signer's certificates.
@param[in] CertDataSize Length of CertData in bytes.
@retval EFI_INVALID_PARAMETER Any input parameter is invalid.
@retval EFI_ACCESS_DENIED An AUTH_CERT_DB_DATA entry with same VariableName
and VendorGuid already exists.
@retval EFI_OUT_OF_RESOURCES The operation is failed due to lack of resources.
@retval EFI_SUCCESS Insert an AUTH_CERT_DB_DATA entry to "certdb" or "certdbv"
**/
EFI_STATUS
InsertCertsToDb (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN UINT32 Attributes,
IN UINT8 *CertData,
IN UINTN CertDataSize
)
{
EFI_STATUS Status;
UINT8 *Data;
UINTN DataSize;
UINT32 VarAttr;
UINT8 *NewCertDb;
UINT32 NewCertDbSize;
UINT32 CertNodeSize;
UINT32 NameSize;
AUTH_CERT_DB_DATA *Ptr;
CHAR16 *DbName;
if ((VariableName == NULL) || (VendorGuid == NULL) || (CertData == NULL)) {
return EFI_INVALID_PARAMETER;
}
if ((Attributes & EFI_VARIABLE_NON_VOLATILE) != 0) {
//
// Get variable "certdb".
//
DbName = EFI_CERT_DB_NAME;
VarAttr = EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
} else {
//
// Get variable "certdbv".
//
DbName = EFI_CERT_DB_VOLATILE_NAME;
VarAttr = EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
}
//
// Get variable "certdb" or "certdbv".
//
Status = AuthServiceInternalFindVariable (
DbName,
&gEfiCertDbGuid,
(VOID **) &Data,
&DataSize
);
if (EFI_ERROR (Status)) {
return Status;
}
if ((DataSize == 0) || (Data == NULL)) {
ASSERT (FALSE);
return EFI_NOT_FOUND;
}
//
// Find whether matching cert node already exists in "certdb" or "certdbv".
// If yes return error.
//
Status = FindCertsFromDb (
VariableName,
VendorGuid,
Data,
DataSize,
NULL,
NULL,
NULL,
NULL
);
if (!EFI_ERROR (Status)) {
ASSERT (FALSE);
return EFI_ACCESS_DENIED;
}
//
// Construct new data content of variable "certdb" or "certdbv".
//
NameSize = (UINT32) StrLen (VariableName);
CertNodeSize = sizeof (AUTH_CERT_DB_DATA) + (UINT32) CertDataSize + NameSize * sizeof (CHAR16);
NewCertDbSize = (UINT32) DataSize + CertNodeSize;
if (NewCertDbSize > mMaxCertDbSize) {
return EFI_OUT_OF_RESOURCES;
}
NewCertDb = (UINT8*) mCertDbStore;
//
// Copy the DB entries before inserting node.
//
CopyMem (NewCertDb, Data, DataSize);
//
// Update CertDbListSize.
//
CopyMem (NewCertDb, &NewCertDbSize, sizeof (UINT32));
//
// Construct new cert node.
//
Ptr = (AUTH_CERT_DB_DATA *) (NewCertDb + DataSize);
CopyGuid (&Ptr->VendorGuid, VendorGuid);
CopyMem (&Ptr->CertNodeSize, &CertNodeSize, sizeof (UINT32));
CopyMem (&Ptr->NameSize, &NameSize, sizeof (UINT32));
CopyMem (&Ptr->CertDataSize, &CertDataSize, sizeof (UINT32));
CopyMem (
(UINT8 *) Ptr + sizeof (AUTH_CERT_DB_DATA),
VariableName,
NameSize * sizeof (CHAR16)
);
CopyMem (
(UINT8 *) Ptr + sizeof (AUTH_CERT_DB_DATA) + NameSize * sizeof (CHAR16),
CertData,
CertDataSize
);
//
// Set "certdb" or "certdbv".
//
Status = AuthServiceInternalUpdateVariable (
DbName,
&gEfiCertDbGuid,
NewCertDb,
NewCertDbSize,
VarAttr
);
return Status;
}
/**
Clean up signer's certificates for common authenticated variable
by corresponding VariableName and VendorGuid from "certdb".
System may break down during Timebased Variable update & certdb update,
make them inconsistent, this function is called in AuthVariable Init
to ensure consistency.
@retval EFI_NOT_FOUND Fail to find variable "certdb".
@retval EFI_OUT_OF_RESOURCES The operation is failed due to lack of resources.
@retval EFI_SUCCESS The operation is completed successfully.
**/
EFI_STATUS
CleanCertsFromDb (
VOID
)
{
UINT32 Offset;
AUTH_CERT_DB_DATA *Ptr;
UINT32 NameSize;
UINT32 NodeSize;
CHAR16 *VariableName;
EFI_STATUS Status;
BOOLEAN CertCleaned;
UINT8 *Data;
UINTN DataSize;
EFI_GUID AuthVarGuid;
AUTH_VARIABLE_INFO AuthVariableInfo;
Status = EFI_SUCCESS;
//
// Get corresponding certificates by VendorGuid and VariableName.
//
do {
CertCleaned = FALSE;
//
// Get latest variable "certdb"
//
Status = AuthServiceInternalFindVariable (
EFI_CERT_DB_NAME,
&gEfiCertDbGuid,
(VOID **) &Data,
&DataSize
);
if (EFI_ERROR (Status)) {
return Status;
}
if ((DataSize == 0) || (Data == NULL)) {
ASSERT (FALSE);
return EFI_NOT_FOUND;
}
Offset = sizeof (UINT32);
while (Offset < (UINT32) DataSize) {
Ptr = (AUTH_CERT_DB_DATA *) (Data + Offset);
NodeSize = ReadUnaligned32 (&Ptr->CertNodeSize);
NameSize = ReadUnaligned32 (&Ptr->NameSize);
//
// Get VarName tailed with '\0'
//
VariableName = AllocateZeroPool((NameSize + 1) * sizeof(CHAR16));
if (VariableName == NULL) {
return EFI_OUT_OF_RESOURCES;
}
CopyMem (VariableName, (UINT8 *) Ptr + sizeof (AUTH_CERT_DB_DATA), NameSize * sizeof(CHAR16));
//
// Keep VarGuid aligned
//
CopyMem (&AuthVarGuid, &Ptr->VendorGuid, sizeof(EFI_GUID));
//
// Find corresponding time auth variable
//
ZeroMem (&AuthVariableInfo, sizeof (AuthVariableInfo));
Status = mAuthVarLibContextIn->FindVariable (
VariableName,
&AuthVarGuid,
&AuthVariableInfo
);
if (EFI_ERROR(Status) || (AuthVariableInfo.Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) == 0) {
Status = DeleteCertsFromDb(
VariableName,
&AuthVarGuid,
AuthVariableInfo.Attributes
);
CertCleaned = TRUE;
DEBUG((EFI_D_INFO, "Recovery!! Cert for Auth Variable %s Guid %g is removed for consistency\n", VariableName, &AuthVarGuid));
FreePool(VariableName);
break;
}
FreePool(VariableName);
Offset = Offset + NodeSize;
}
} while (CertCleaned);
return Status;
}
/**
Process variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set
Caution: This function may receive untrusted input.
This function may be invoked in SMM mode, and datasize and data are external input.
This function will do basic validation, before parse the data.
This function will parse the authentication carefully to avoid security issues, like
buffer overflow, integer overflow.
@param[in] VariableName Name of Variable to be found.
@param[in] VendorGuid Variable vendor GUID.
@param[in] Data Data pointer.
@param[in] DataSize Size of Data found. If size is less than the
data, this value contains the required size.
@param[in] Attributes Attribute value of the variable.
@param[in] AuthVarType Verify against PK, KEK database, private database or certificate in data payload.
@param[in] OrgTimeStamp Pointer to original time stamp,
original variable is not found if NULL.
@param[out] VarPayloadPtr Pointer to variable payload address.
@param[out] VarPayloadSize Pointer to variable payload size.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_SECURITY_VIOLATION The variable does NOT pass the validation
check carried out by the firmware.
@retval EFI_OUT_OF_RESOURCES Failed to process variable due to lack
of resources.
@retval EFI_SUCCESS Variable pass validation successfully.
**/
EFI_STATUS
VerifyTimeBasedPayload (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN VOID *Data,
IN UINTN DataSize,
IN UINT32 Attributes,
IN AUTHVAR_TYPE AuthVarType,
IN EFI_TIME *OrgTimeStamp,
OUT UINT8 **VarPayloadPtr,
OUT UINTN *VarPayloadSize
)
{
EFI_VARIABLE_AUTHENTICATION_2 *CertData;
UINT8 *SigData;
UINT32 SigDataSize;
UINT8 *PayloadPtr;
UINTN PayloadSize;
UINT32 Attr;
BOOLEAN VerifyStatus;
EFI_STATUS Status;
EFI_SIGNATURE_LIST *CertList;
EFI_SIGNATURE_DATA *Cert;
UINTN Index;
UINTN CertCount;
UINT32 KekDataSize;
UINT8 *NewData;
UINTN NewDataSize;
UINT8 *Buffer;
UINTN Length;
UINT8 *RootCert;
UINTN RootCertSize;
UINT8 *SignerCerts;
UINTN CertStackSize;
UINT8 *CertsInCertDb;
UINT32 CertsSizeinDb;
VerifyStatus = FALSE;
CertData = NULL;
NewData = NULL;
Attr = Attributes;
SignerCerts = NULL;
RootCert = NULL;
CertsInCertDb = NULL;
//
// When the attribute EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS is
// set, then the Data buffer shall begin with an instance of a complete (and serialized)
// EFI_VARIABLE_AUTHENTICATION_2 descriptor. The descriptor shall be followed by the new
// variable value and DataSize shall reflect the combined size of the descriptor and the new
// variable value. The authentication descriptor is not part of the variable data and is not
// returned by subsequent calls to GetVariable().
//
CertData = (EFI_VARIABLE_AUTHENTICATION_2 *) Data;
//
// Verify that Pad1, Nanosecond, TimeZone, Daylight and Pad2 components of the
// TimeStamp value are set to zero.
//
if ((CertData->TimeStamp.Pad1 != 0) ||
(CertData->TimeStamp.Nanosecond != 0) ||
(CertData->TimeStamp.TimeZone != 0) ||
(CertData->TimeStamp.Daylight != 0) ||
(CertData->TimeStamp.Pad2 != 0)) {
return EFI_SECURITY_VIOLATION;
}
if ((OrgTimeStamp != NULL) && ((Attributes & EFI_VARIABLE_APPEND_WRITE) == 0)) {
if (AuthServiceInternalCompareTimeStamp (&CertData->TimeStamp, OrgTimeStamp)) {
//
// TimeStamp check fail, suspicious replay attack, return EFI_SECURITY_VIOLATION.
//
return EFI_SECURITY_VIOLATION;
}
}
//
// wCertificateType should be WIN_CERT_TYPE_EFI_GUID.
// Cert type should be EFI_CERT_TYPE_PKCS7_GUID.
//
if ((CertData->AuthInfo.Hdr.wCertificateType != WIN_CERT_TYPE_EFI_GUID) ||
!CompareGuid (&CertData->AuthInfo.CertType, &gEfiCertPkcs7Guid)) {
//
// Invalid AuthInfo type, return EFI_SECURITY_VIOLATION.
//
return EFI_SECURITY_VIOLATION;
}
//
// Find out Pkcs7 SignedData which follows the EFI_VARIABLE_AUTHENTICATION_2 descriptor.
// AuthInfo.Hdr.dwLength is the length of the entire certificate, including the length of the header.
//
SigData = CertData->AuthInfo.CertData;
SigDataSize = CertData->AuthInfo.Hdr.dwLength - (UINT32) (OFFSET_OF (WIN_CERTIFICATE_UEFI_GUID, CertData));
//
// SignedData.digestAlgorithms shall contain the digest algorithm used when preparing the
// signature. Only a digest algorithm of SHA-256 is accepted.
//
// According to PKCS#7 Definition:
// SignedData ::= SEQUENCE {
// version Version,
// digestAlgorithms DigestAlgorithmIdentifiers,
// contentInfo ContentInfo,
// .... }
// The DigestAlgorithmIdentifiers can be used to determine the hash algorithm
// in VARIABLE_AUTHENTICATION_2 descriptor.
// This field has the fixed offset (+13) and be calculated based on two bytes of length encoding.
//
if ((Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0) {
if (SigDataSize >= (13 + sizeof (mSha256OidValue))) {
if (((*(SigData + 1) & TWO_BYTE_ENCODE) != TWO_BYTE_ENCODE) ||
(CompareMem (SigData + 13, &mSha256OidValue, sizeof (mSha256OidValue)) != 0)) {
return EFI_SECURITY_VIOLATION;
}
}
}
//
// Find out the new data payload which follows Pkcs7 SignedData directly.
//
PayloadPtr = SigData + SigDataSize;
PayloadSize = DataSize - OFFSET_OF_AUTHINFO2_CERT_DATA - (UINTN) SigDataSize;
//
// Construct a serialization buffer of the values of the VariableName, VendorGuid and Attributes
// parameters of the SetVariable() call and the TimeStamp component of the
// EFI_VARIABLE_AUTHENTICATION_2 descriptor followed by the variable's new value
// i.e. (VariableName, VendorGuid, Attributes, TimeStamp, Data)
//
NewDataSize = PayloadSize + sizeof (EFI_TIME) + sizeof (UINT32) +
sizeof (EFI_GUID) + StrSize (VariableName) - sizeof (CHAR16);
//
// Here is to reuse scratch data area(at the end of volatile variable store)
// to reduce SMRAM consumption for SMM variable driver.
// The scratch buffer is enough to hold the serialized data and safe to use,
// because it is only used at here to do verification temporarily first
// and then used in UpdateVariable() for a time based auth variable set.
//
Status = mAuthVarLibContextIn->GetScratchBuffer (&NewDataSize, (VOID **) &NewData);
if (EFI_ERROR (Status)) {
return EFI_OUT_OF_RESOURCES;
}
Buffer = NewData;
Length = StrLen (VariableName) * sizeof (CHAR16);
CopyMem (Buffer, VariableName, Length);
Buffer += Length;
Length = sizeof (EFI_GUID);
CopyMem (Buffer, VendorGuid, Length);
Buffer += Length;
Length = sizeof (UINT32);
CopyMem (Buffer, &Attr, Length);
Buffer += Length;
Length = sizeof (EFI_TIME);
CopyMem (Buffer, &CertData->TimeStamp, Length);
Buffer += Length;
CopyMem (Buffer, PayloadPtr, PayloadSize);
if (AuthVarType == AuthVarTypePk) {
//
// Verify that the signature has been made with the current Platform Key (no chaining for PK).
// First, get signer's certificates from SignedData.
//
VerifyStatus = Pkcs7GetSigners (
SigData,
SigDataSize,
&SignerCerts,
&CertStackSize,
&RootCert,
&RootCertSize
);
if (!VerifyStatus) {
goto Exit;
}
//
// Second, get the current platform key from variable. Check whether it's identical with signer's certificates
// in SignedData. If not, return error immediately.
//
Status = AuthServiceInternalFindVariable (
EFI_PLATFORM_KEY_NAME,
&gEfiGlobalVariableGuid,
&Data,
&DataSize
);
if (EFI_ERROR (Status)) {
VerifyStatus = FALSE;
goto Exit;
}
CertList = (EFI_SIGNATURE_LIST *) Data;
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
if ((RootCertSize != (CertList->SignatureSize - (sizeof (EFI_SIGNATURE_DATA) - 1))) ||
(CompareMem (Cert->SignatureData, RootCert, RootCertSize) != 0)) {
VerifyStatus = FALSE;
goto Exit;
}
//
// Verify Pkcs7 SignedData via Pkcs7Verify library.
//
VerifyStatus = Pkcs7Verify (
SigData,
SigDataSize,
RootCert,
RootCertSize,
NewData,
NewDataSize
);
} else if (AuthVarType == AuthVarTypeKek) {
//
// Get KEK database from variable.
//
Status = AuthServiceInternalFindVariable (
EFI_KEY_EXCHANGE_KEY_NAME,
&gEfiGlobalVariableGuid,
&Data,
&DataSize
);
if (EFI_ERROR (Status)) {
return Status;
}
//
// Ready to verify Pkcs7 SignedData. Go through KEK Signature Database to find out X.509 CertList.
//
KekDataSize = (UINT32) DataSize;
CertList = (EFI_SIGNATURE_LIST *) Data;
while ((KekDataSize > 0) && (KekDataSize >= CertList->SignatureListSize)) {
if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
for (Index = 0; Index < CertCount; Index++) {
//
// Iterate each Signature Data Node within this CertList for a verify
//
RootCert = Cert->SignatureData;
RootCertSize = CertList->SignatureSize - (sizeof (EFI_SIGNATURE_DATA) - 1);
//
// Verify Pkcs7 SignedData via Pkcs7Verify library.
//
VerifyStatus = Pkcs7Verify (
SigData,
SigDataSize,
RootCert,
RootCertSize,
NewData,
NewDataSize
);
if (VerifyStatus) {
goto Exit;
}
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
}
}
KekDataSize -= CertList->SignatureListSize;
CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
}
} else if (AuthVarType == AuthVarTypePriv) {
//
// Process common authenticated variable except PK/KEK/DB/DBX/DBT.
// Get signer's certificates from SignedData.
//
VerifyStatus = Pkcs7GetSigners (
SigData,
SigDataSize,
&SignerCerts,
&CertStackSize,
&RootCert,
&RootCertSize
);
if (!VerifyStatus) {
goto Exit;
}
//
// Get previously stored signer's certificates from certdb or certdbv for existing
// variable. Check whether they are identical with signer's certificates
// in SignedData. If not, return error immediately.
//
if (OrgTimeStamp != NULL) {
VerifyStatus = FALSE;
Status = GetCertsFromDb (VariableName, VendorGuid, Attributes, &CertsInCertDb, &CertsSizeinDb);
if (EFI_ERROR (Status)) {
goto Exit;
}
if ((CertStackSize != CertsSizeinDb) ||
(CompareMem (SignerCerts, CertsInCertDb, CertsSizeinDb) != 0)) {
goto Exit;
}
}
VerifyStatus = Pkcs7Verify (
SigData,
SigDataSize,
RootCert,
RootCertSize,
NewData,
NewDataSize
);
if (!VerifyStatus) {
goto Exit;
}
if ((OrgTimeStamp == NULL) && (PayloadSize != 0)) {
//
// Insert signer's certificates when adding a new common authenticated variable.
//
Status = InsertCertsToDb (VariableName, VendorGuid, Attributes, SignerCerts, CertStackSize);
if (EFI_ERROR (Status)) {
VerifyStatus = FALSE;
goto Exit;
}
}
} else if (AuthVarType == AuthVarTypePayload) {
CertList = (EFI_SIGNATURE_LIST *) PayloadPtr;
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
RootCert = Cert->SignatureData;
RootCertSize = CertList->SignatureSize - (sizeof (EFI_SIGNATURE_DATA) - 1);
//
// Verify Pkcs7 SignedData via Pkcs7Verify library.
//
VerifyStatus = Pkcs7Verify (
SigData,
SigDataSize,
RootCert,
RootCertSize,
NewData,
NewDataSize
);
} else {
return EFI_SECURITY_VIOLATION;
}
Exit:
if (AuthVarType == AuthVarTypePk || AuthVarType == AuthVarTypePriv) {
Pkcs7FreeSigners (RootCert);
Pkcs7FreeSigners (SignerCerts);
}
if (!VerifyStatus) {
return EFI_SECURITY_VIOLATION;
}
Status = CheckSignatureListFormat(VariableName, VendorGuid, PayloadPtr, PayloadSize);
if (EFI_ERROR (Status)) {
return Status;
}
*VarPayloadPtr = PayloadPtr;
*VarPayloadSize = PayloadSize;
return EFI_SUCCESS;
}
/**
Process variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set
Caution: This function may receive untrusted input.
This function may be invoked in SMM mode, and datasize and data are external input.
This function will do basic validation, before parse the data.
This function will parse the authentication carefully to avoid security issues, like
buffer overflow, integer overflow.
@param[in] VariableName Name of Variable to be found.
@param[in] VendorGuid Variable vendor GUID.
@param[in] Data Data pointer.
@param[in] DataSize Size of Data found. If size is less than the
data, this value contains the required size.
@param[in] Attributes Attribute value of the variable.
@param[in] AuthVarType Verify against PK, KEK database, private database or certificate in data payload.
@param[out] VarDel Delete the variable or not.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_SECURITY_VIOLATION The variable does NOT pass the validation
check carried out by the firmware.
@retval EFI_OUT_OF_RESOURCES Failed to process variable due to lack
of resources.
@retval EFI_SUCCESS Variable pass validation successfully.
**/
EFI_STATUS
VerifyTimeBasedPayloadAndUpdate (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN VOID *Data,
IN UINTN DataSize,
IN UINT32 Attributes,
IN AUTHVAR_TYPE AuthVarType,
OUT BOOLEAN *VarDel
)
{
EFI_STATUS Status;
EFI_STATUS FindStatus;
UINT8 *PayloadPtr;
UINTN PayloadSize;
EFI_VARIABLE_AUTHENTICATION_2 *CertData;
AUTH_VARIABLE_INFO OrgVariableInfo;
BOOLEAN IsDel;
ZeroMem (&OrgVariableInfo, sizeof (OrgVariableInfo));
FindStatus = mAuthVarLibContextIn->FindVariable (
VariableName,
VendorGuid,
&OrgVariableInfo
);
Status = VerifyTimeBasedPayload (
VariableName,
VendorGuid,
Data,
DataSize,
Attributes,
AuthVarType,
(!EFI_ERROR (FindStatus)) ? OrgVariableInfo.TimeStamp : NULL,
&PayloadPtr,
&PayloadSize
);
if (EFI_ERROR (Status)) {
return Status;
}
if (!EFI_ERROR(FindStatus)
&& (PayloadSize == 0)
&& ((Attributes & EFI_VARIABLE_APPEND_WRITE) == 0)) {
IsDel = TRUE;
} else {
IsDel = FALSE;
}
CertData = (EFI_VARIABLE_AUTHENTICATION_2 *) Data;
//
// Final step: Update/Append Variable if it pass Pkcs7Verify
//
Status = AuthServiceInternalUpdateVariableWithTimeStamp (
VariableName,
VendorGuid,
PayloadPtr,
PayloadSize,
Attributes,
&CertData->TimeStamp
);
//
// Delete signer's certificates when delete the common authenticated variable.
//
if (IsDel && AuthVarType == AuthVarTypePriv && !EFI_ERROR(Status) ) {
Status = DeleteCertsFromDb (VariableName, VendorGuid, Attributes);
}
if (VarDel != NULL) {
if (IsDel && !EFI_ERROR(Status)) {
*VarDel = TRUE;
} else {
*VarDel = FALSE;
}
}
return Status;
}