src/credentials/PersistentStorageOpCertStore.cpp - third_party/github/project-chip/connectedhomeip - Git at Google

 /*
  *    Copyright (c) 2022 Project CHIP Authors
  *    All rights reserved.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
  *    You may obtain a copy of the License at
  *
  *        http://www.apache.org/licenses/LICENSE-2.0
  *
  *    Unless required by applicable law or agreed to in writing, software
  *    distributed under the License is distributed on an "AS IS" BASIS,
  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *    See the License for the specific language governing permissions and
  *    limitations under the License.
  */

 #include <credentials/CHIPCert.h>
 #include <lib/core/CHIPError.h>
 #include <lib/core/CHIPPersistentStorageDelegate.h>
 #include <lib/core/DataModelTypes.h>
 #include <lib/core/TLV.h>
 #include <lib/support/CHIPMem.h>
 #include <lib/support/CodeUtils.h>
 #include <lib/support/DefaultStorageKeyAllocator.h>
 #include <lib/support/SafeInt.h>
 #include <lib/support/ScopedBuffer.h>

 #include "PersistentStorageOpCertStore.h"

 namespace chip {
 namespace Credentials {

 namespace {

 using CertChainElement = OperationalCertificateStore::CertChainElement;

 StorageKeyName GetStorageKeyForCert(FabricIndex fabricIndex, CertChainElement element)
 {
     switch (element)
     {
     case CertChainElement::kNoc:
         return DefaultStorageKeyAllocator::FabricNOC(fabricIndex);
         break;
     case CertChainElement::kIcac:
         return DefaultStorageKeyAllocator::FabricICAC(fabricIndex);
         break;
     case CertChainElement::kRcac:
         return DefaultStorageKeyAllocator::FabricRCAC(fabricIndex);
         break;
     default:
         break;
     }

     return StorageKeyName::Uninitialized();
 }

 bool StorageHasCertificate(PersistentStorageDelegate * storage, FabricIndex fabricIndex, CertChainElement element)
 {
     StorageKeyName storageKey = GetStorageKeyForCert(fabricIndex, element);

     if (!storageKey)
     {
         return false;
     }

     // TODO(#16958): need to actually read the cert to know if it's there due to platforms not
     //               properly enforcing CHIP_ERROR_BUFFER_TOO_SMALL behavior needed by
     //               PersistentStorageDelegate.
     uint8_t placeHolderCertBuffer[kMaxCHIPCertLength];

     uint16_t keySize = sizeof(placeHolderCertBuffer);
     CHIP_ERROR err   = storage->SyncGetKeyValue(storageKey.KeyName(), &placeHolderCertBuffer[0], keySize);

     return (err == CHIP_NO_ERROR);
 }

 CHIP_ERROR LoadCertFromStorage(PersistentStorageDelegate * storage, FabricIndex fabricIndex, CertChainElement element,
                                MutableByteSpan & outCert)
 {
     StorageKeyName storageKey = GetStorageKeyForCert(fabricIndex, element);
     if (!storageKey)
     {
         return CHIP_ERROR_INTERNAL;
     }

     uint16_t keySize = static_cast<uint16_t>(outCert.size());
     CHIP_ERROR err   = storage->SyncGetKeyValue(storageKey.KeyName(), outCert.data(), keySize);

     // Not finding an ICAC means we don't have one, so adjust to meet the API contract, where
     // outCert.empty() will be true;
     if ((element == CertChainElement::kIcac) && (err == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND))
     {
         outCert.reduce_size(0);
         return CHIP_ERROR_NOT_FOUND;
     }

     if (err == CHIP_NO_ERROR)
     {
         outCert.reduce_size(keySize);
     }
     else if (err == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND)
     {
         // Convert persisted storage error to CHIP_ERROR_NOT_FOUND so that
         // `PersistentStorageOpCertStore::GetCertificate` doesn't need to convert.
         err = CHIP_ERROR_NOT_FOUND;
     }

     return err;
 }

 CHIP_ERROR SaveCertToStorage(PersistentStorageDelegate * storage, FabricIndex fabricIndex, CertChainElement element,
                              const ByteSpan & cert)
 {
     StorageKeyName storageKey = GetStorageKeyForCert(fabricIndex, element);
     if (!storageKey)
     {
         return CHIP_ERROR_INTERNAL;
     }

     // If provided an empty ICAC, we delete the ICAC key previously used. If not there, it's OK
     if ((element == CertChainElement::kIcac) && (cert.empty()))
     {
         CHIP_ERROR err = storage->SyncDeleteKeyValue(storageKey.KeyName());
         if ((err == CHIP_NO_ERROR) || (err == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND))
         {
             return CHIP_NO_ERROR;
         }
         return err;
     }

     return storage->SyncSetKeyValue(storageKey.KeyName(), cert.data(), static_cast<uint16_t>(cert.size()));
 }

 CHIP_ERROR DeleteCertFromStorage(PersistentStorageDelegate * storage, FabricIndex fabricIndex, CertChainElement element)
 {
     StorageKeyName storageKey = GetStorageKeyForCert(fabricIndex, element);
     if (!storageKey)
     {
         return CHIP_ERROR_INTERNAL;
     }
     return storage->SyncDeleteKeyValue(storageKey.KeyName());
 }

 } // namespace

 bool PersistentStorageOpCertStore::HasPendingRootCert() const
 {
     if (mStorage == nullptr)
     {
         return false;
     }

     return (mPendingRcac.Get() != nullptr) && mStateFlags.Has(StateFlags::kAddNewTrustedRootCalled);
 }

 bool PersistentStorageOpCertStore::HasPendingNocChain() const
 {
     if (mStorage == nullptr)
     {
         return false;
     }

     return (mPendingNoc.Get() != nullptr) && mStateFlags.HasAny(StateFlags::kAddNewOpCertsCalled, StateFlags::kUpdateOpCertsCalled);
 }

 bool PersistentStorageOpCertStore::HasCertificateForFabric(FabricIndex fabricIndex, CertChainElement element) const
 {
     if ((mStorage == nullptr) || !IsValidFabricIndex(fabricIndex))
     {
         return false;
     }

     // FabricIndex matches pending, we MAY have some pending data
     if (fabricIndex == mPendingFabricIndex)
     {
         switch (element)
         {
         case CertChainElement::kRcac:
             if (mPendingRcac.Get() != nullptr)
             {
                 return true;
             }
             break;
         case CertChainElement::kIcac:
             if (mPendingIcac.Get() != nullptr)
             {
                 return true;
             }
             // If we have a pending NOC and no pending ICAC, don't delegate to storage, return not found here
             // since in the pending state, there truly is nothing.
             if (mPendingNoc.Get() != nullptr)
             {
                 return false;
             }
             break;
         case CertChainElement::kNoc:
             if (mPendingNoc.Get() != nullptr)
             {
                 return true;
             }
             break;
         default:
             return false;
         }
     }

     return StorageHasCertificate(mStorage, fabricIndex, element);
 }

 CHIP_ERROR PersistentStorageOpCertStore::AddNewTrustedRootCertForFabric(FabricIndex fabricIndex, const ByteSpan & rcac)
 {
     ReturnErrorCodeIf(mStorage == nullptr, CHIP_ERROR_INCORRECT_STATE);
     ReturnErrorCodeIf(!IsValidFabricIndex(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);
     ReturnErrorCodeIf(rcac.empty() || (rcac.size() > Credentials::kMaxCHIPCertLength), CHIP_ERROR_INVALID_ARGUMENT);

     ReturnErrorCodeIf(mStateFlags.HasAny(StateFlags::kUpdateOpCertsCalled, StateFlags::kAddNewTrustedRootCalled,
                                          StateFlags::kAddNewOpCertsCalled),
                       CHIP_ERROR_INCORRECT_STATE);
     ReturnErrorCodeIf(StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kRcac), CHIP_ERROR_INCORRECT_STATE);

     Platform::ScopedMemoryBufferWithSize<uint8_t> rcacBuf;
     ReturnErrorCodeIf(!rcacBuf.Alloc(rcac.size()), CHIP_ERROR_NO_MEMORY);
     memcpy(rcacBuf.Get(), rcac.data(), rcac.size());

     mPendingRcac = std::move(rcacBuf);

     mPendingFabricIndex = fabricIndex;
     mStateFlags.Set(StateFlags::kAddNewTrustedRootCalled);

     return CHIP_NO_ERROR;
 }

 CHIP_ERROR PersistentStorageOpCertStore::AddNewOpCertsForFabric(FabricIndex fabricIndex, const ByteSpan & noc,
                                                                 const ByteSpan & icac)
 {
     ReturnErrorCodeIf(mStorage == nullptr, CHIP_ERROR_INCORRECT_STATE);
     ReturnErrorCodeIf(!IsValidFabricIndex(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);
     ReturnErrorCodeIf(noc.empty() || (noc.size() > Credentials::kMaxCHIPCertLength), CHIP_ERROR_INVALID_ARGUMENT);
     ReturnErrorCodeIf(icac.size() > Credentials::kMaxCHIPCertLength, CHIP_ERROR_INVALID_ARGUMENT);

     // Can't have called UpdateOpCertsForFabric first, or called with pending certs
     ReturnErrorCodeIf(mStateFlags.HasAny(StateFlags::kUpdateOpCertsCalled, StateFlags::kAddNewOpCertsCalled),
                       CHIP_ERROR_INCORRECT_STATE);

     // Need to have trusted roots installed to make the chain valid
     ReturnErrorCodeIf(!mStateFlags.Has(StateFlags::kAddNewTrustedRootCalled), CHIP_ERROR_INCORRECT_STATE);

     // fabricIndex must match the current pending fabric
     ReturnErrorCodeIf(fabricIndex != mPendingFabricIndex, CHIP_ERROR_INVALID_FABRIC_INDEX);

     // Can't have persisted NOC/ICAC for same fabric if adding
     ReturnErrorCodeIf(StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kNoc), CHIP_ERROR_INCORRECT_STATE);
     ReturnErrorCodeIf(StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kIcac), CHIP_ERROR_INCORRECT_STATE);

     Platform::ScopedMemoryBufferWithSize<uint8_t> nocBuf;
     ReturnErrorCodeIf(!nocBuf.Alloc(noc.size()), CHIP_ERROR_NO_MEMORY);
     memcpy(nocBuf.Get(), noc.data(), noc.size());

     Platform::ScopedMemoryBufferWithSize<uint8_t> icacBuf;
     if (icac.size() > 0)
     {
         ReturnErrorCodeIf(!icacBuf.Alloc(icac.size()), CHIP_ERROR_NO_MEMORY);
         memcpy(icacBuf.Get(), icac.data(), icac.size());
     }

     mPendingNoc  = std::move(nocBuf);
     mPendingIcac = std::move(icacBuf);

     mStateFlags.Set(StateFlags::kAddNewOpCertsCalled);

     return CHIP_NO_ERROR;
 }

 CHIP_ERROR PersistentStorageOpCertStore::UpdateOpCertsForFabric(FabricIndex fabricIndex, const ByteSpan & noc,
                                                                 const ByteSpan & icac)
 {
     ReturnErrorCodeIf(mStorage == nullptr, CHIP_ERROR_INCORRECT_STATE);
     ReturnErrorCodeIf(!IsValidFabricIndex(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);
     ReturnErrorCodeIf(noc.empty() || (noc.size() > Credentials::kMaxCHIPCertLength), CHIP_ERROR_INVALID_ARGUMENT);
     ReturnErrorCodeIf(icac.size() > Credentials::kMaxCHIPCertLength, CHIP_ERROR_INVALID_ARGUMENT);

     // Can't have called AddNewOpCertsForFabric first, and should never get here after AddNewTrustedRootCertForFabric.
     ReturnErrorCodeIf(mStateFlags.HasAny(StateFlags::kAddNewOpCertsCalled, StateFlags::kAddNewTrustedRootCalled),
                       CHIP_ERROR_INCORRECT_STATE);

     // Can't have already pending NOC from UpdateOpCerts not yet committed
     ReturnErrorCodeIf(mStateFlags.Has(StateFlags::kUpdateOpCertsCalled), CHIP_ERROR_INCORRECT_STATE);

     // Need to have trusted roots installed to make the chain valid
     ReturnErrorCodeIf(!StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kRcac), CHIP_ERROR_INCORRECT_STATE);

     // Must have persisted NOC for same fabric if updating
     ReturnErrorCodeIf(!StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kNoc), CHIP_ERROR_INCORRECT_STATE);

     // Don't check for ICAC, we may not have had one before, but assume that if NOC is there, a
     // previous chain was at least partially there

     Platform::ScopedMemoryBufferWithSize<uint8_t> nocBuf;
     ReturnErrorCodeIf(!nocBuf.Alloc(noc.size()), CHIP_ERROR_NO_MEMORY);
     memcpy(nocBuf.Get(), noc.data(), noc.size());

     Platform::ScopedMemoryBufferWithSize<uint8_t> icacBuf;
     if (icac.size() > 0)
     {
         ReturnErrorCodeIf(!icacBuf.Alloc(icac.size()), CHIP_ERROR_NO_MEMORY);
         memcpy(icacBuf.Get(), icac.data(), icac.size());
     }

     mPendingNoc  = std::move(nocBuf);
     mPendingIcac = std::move(icacBuf);

     // For NOC update, UpdateOpCertsForFabric is what determines the pending fabric index,
     // not a previous AddNewTrustedRootCertForFabric call.
     mPendingFabricIndex = fabricIndex;

     mStateFlags.Set(StateFlags::kUpdateOpCertsCalled);

     return CHIP_NO_ERROR;
 }

 CHIP_ERROR PersistentStorageOpCertStore::CommitOpCertsForFabric(FabricIndex fabricIndex)
 {
     VerifyOrReturnError(mStorage != nullptr, CHIP_ERROR_INCORRECT_STATE);
     VerifyOrReturnError(IsValidFabricIndex(fabricIndex) && (fabricIndex == mPendingFabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);

     VerifyOrReturnError(HasPendingNocChain(), CHIP_ERROR_INCORRECT_STATE);
     if (HasPendingRootCert())
     {
         // Neither of these conditions should have occurred based on other interlocks, but since
         // committing certificates is a dangerous operation, we absolutely validate our assumptions.
         ReturnErrorCodeIf(mStateFlags.Has(StateFlags::kUpdateOpCertsCalled), CHIP_ERROR_INCORRECT_STATE);
         ReturnErrorCodeIf(!mStateFlags.Has(StateFlags::kAddNewTrustedRootCalled), CHIP_ERROR_INCORRECT_STATE);
     }

     // TODO: Handle transaction marking to revert partial certs at next boot if we get interrupted by reboot.

     // Start committing NOC first so we don't have dangling roots if one was added.
     ByteSpan pendingNocSpan{ mPendingNoc.Get(), mPendingNoc.AllocatedSize() };
     CHIP_ERROR nocErr = SaveCertToStorage(mStorage, mPendingFabricIndex, CertChainElement::kNoc, pendingNocSpan);

     // ICAC storage handles deleting on empty/missing
     ByteSpan pendingIcacSpan{ mPendingIcac.Get(), mPendingIcac.AllocatedSize() };
     CHIP_ERROR icacErr = SaveCertToStorage(mStorage, mPendingFabricIndex, CertChainElement::kIcac, pendingIcacSpan);

     CHIP_ERROR rcacErr = CHIP_NO_ERROR;
     if (HasPendingRootCert())
     {
         ByteSpan pendingRcacSpan{ mPendingRcac.Get(), mPendingRcac.AllocatedSize() };
         rcacErr = SaveCertToStorage(mStorage, mPendingFabricIndex, CertChainElement::kRcac, pendingRcacSpan);
     }

     // Remember which was the first error, and if any error occurred.
     CHIP_ERROR stickyErr = nocErr;
     stickyErr            = (stickyErr != CHIP_NO_ERROR) ? stickyErr : icacErr;
     stickyErr            = (stickyErr != CHIP_NO_ERROR) ? stickyErr : rcacErr;

     if (stickyErr != CHIP_NO_ERROR)
     {
         // On Adds rather than updates, remove anything possibly stored for the new fabric on partial
         // failure.
         if (mStateFlags.Has(StateFlags::kAddNewOpCertsCalled))
         {
             (void) DeleteCertFromStorage(mStorage, mPendingFabricIndex, CertChainElement::kNoc);
             (void) DeleteCertFromStorage(mStorage, mPendingFabricIndex, CertChainElement::kIcac);
         }
         if (mStateFlags.Has(StateFlags::kAddNewTrustedRootCalled))
         {
             (void) DeleteCertFromStorage(mStorage, mPendingFabricIndex, CertChainElement::kRcac);
         }
         if (mStateFlags.Has(StateFlags::kUpdateOpCertsCalled))
         {
             // Can't do anything to clean-up here, but pretty sure the fabric is broken now...
             // TODO: Handle transaction marking to revert certs if somehow failing store on update by pre-backing-up opcerts
         }

         return stickyErr;
     }

     // If we got here, we succeeded and can reset the pending certs: next `GetCertificate` will use the stored certs
     RevertPendingOpCerts();
     return CHIP_NO_ERROR;
 }

 bool PersistentStorageOpCertStore::HasAnyCertificateForFabric(FabricIndex fabricIndex) const
 {
     VerifyOrReturnError(IsValidFabricIndex(fabricIndex), false);

     bool rcacMissing = !StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kRcac);
     bool icacMissing = !StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kIcac);
     bool nocMissing  = !StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kNoc);
     bool anyPending  = (mPendingRcac.Get() != nullptr) || (mPendingIcac.Get() != nullptr) || (mPendingNoc.Get() != nullptr);

     if (rcacMissing && icacMissing && nocMissing && !anyPending)
     {
         return false;
     }

     return true;
 }

 CHIP_ERROR PersistentStorageOpCertStore::RemoveOpCertsForFabric(FabricIndex fabricIndex)
 {
     VerifyOrReturnError(mStorage != nullptr, CHIP_ERROR_INCORRECT_STATE);
     VerifyOrReturnError(IsValidFabricIndex(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);

     // If there was *no* state, pending or persisted, we have an error
     ReturnErrorCodeIf(!HasAnyCertificateForFabric(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);

     // Clear any pending state
     RevertPendingOpCerts();

     // Remove all persisted certs for the given fabric, blindly
     CHIP_ERROR nocErr  = DeleteCertFromStorage(mStorage, fabricIndex, CertChainElement::kNoc);
     CHIP_ERROR icacErr = DeleteCertFromStorage(mStorage, fabricIndex, CertChainElement::kIcac);
     CHIP_ERROR rcacErr = DeleteCertFromStorage(mStorage, fabricIndex, CertChainElement::kRcac);

     // Ignore missing cert errors
     nocErr  = (nocErr == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND) ? CHIP_NO_ERROR : nocErr;
     icacErr = (icacErr == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND) ? CHIP_NO_ERROR : icacErr;
     rcacErr = (rcacErr == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND) ? CHIP_NO_ERROR : rcacErr;

     // Find the first error and return that
     CHIP_ERROR stickyErr = nocErr;
     stickyErr            = (stickyErr != CHIP_NO_ERROR) ? stickyErr : icacErr;
     stickyErr            = (stickyErr != CHIP_NO_ERROR) ? stickyErr : rcacErr;

     return stickyErr;
 }

 CHIP_ERROR PersistentStorageOpCertStore::GetPendingCertificate(FabricIndex fabricIndex, CertChainElement element,
                                                                MutableByteSpan & outCertificate) const
 {
     if (fabricIndex != mPendingFabricIndex)
     {
         return CHIP_ERROR_NOT_FOUND;
     }

     // FabricIndex matches pending, we MAY have some pending data
     switch (element)
     {
     case CertChainElement::kRcac:
         if (mPendingRcac.Get() != nullptr)
         {
             ByteSpan rcacSpan{ mPendingRcac.Get(), mPendingRcac.AllocatedSize() };
             return CopySpanToMutableSpan(rcacSpan, outCertificate);
         }
         break;
     case CertChainElement::kIcac:
         if (mPendingIcac.Get() != nullptr)
         {
             ByteSpan icacSpan{ mPendingIcac.Get(), mPendingIcac.AllocatedSize() };
             return CopySpanToMutableSpan(icacSpan, outCertificate);
         }
         break;
     case CertChainElement::kNoc:
         if (mPendingNoc.Get() != nullptr)
         {
             ByteSpan nocSpan{ mPendingNoc.Get(), mPendingNoc.AllocatedSize() };
             return CopySpanToMutableSpan(nocSpan, outCertificate);
         }
         break;
     default:
         return CHIP_ERROR_INVALID_ARGUMENT;
     }

     return CHIP_ERROR_NOT_FOUND;
 }

 CHIP_ERROR PersistentStorageOpCertStore::GetCertificate(FabricIndex fabricIndex, CertChainElement element,
                                                         MutableByteSpan & outCertificate) const
 {
     VerifyOrReturnError(mStorage != nullptr, CHIP_ERROR_INCORRECT_STATE);
     VerifyOrReturnError(IsValidFabricIndex(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);

     // Handle case of pending data
     CHIP_ERROR err = GetPendingCertificate(fabricIndex, element, outCertificate);
     if ((err == CHIP_NO_ERROR) || (err != CHIP_ERROR_NOT_FOUND))
     {
         // Found in pending, or got a deeper error: return the pending cert status.
         return err;
     }

     // If we have a pending NOC and no pending ICAC, don't delegate to storage, return not found here
     // since in the pending state, there truly is nothing.

     if ((err == CHIP_ERROR_NOT_FOUND) && (element == CertChainElement::kIcac) && (mPendingNoc.Get() != nullptr))
     {
         // Don't delegate to storage if we just have a pending NOC and are missing the ICAC
         return CHIP_ERROR_NOT_FOUND;
     }

     // Not found in pending, let's look in persisted
     return LoadCertFromStorage(mStorage, fabricIndex, element, outCertificate);
 }

 } // namespace Credentials
 } // namespace chip
	/*
	* Copyright (c) 2022 Project CHIP Authors
	* All rights reserved.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <credentials/CHIPCert.h>
	#include <lib/core/CHIPError.h>
	#include <lib/core/CHIPPersistentStorageDelegate.h>
	#include <lib/core/DataModelTypes.h>
	#include <lib/core/TLV.h>
	#include <lib/support/CHIPMem.h>
	#include <lib/support/CodeUtils.h>
	#include <lib/support/DefaultStorageKeyAllocator.h>
	#include <lib/support/SafeInt.h>
	#include <lib/support/ScopedBuffer.h>

	#include "PersistentStorageOpCertStore.h"

	namespace chip {
	namespace Credentials {

	namespace {

	using CertChainElement = OperationalCertificateStore::CertChainElement;

	StorageKeyName GetStorageKeyForCert(FabricIndex fabricIndex, CertChainElement element)
	{
	switch (element)
	{
	case CertChainElement::kNoc:
	return DefaultStorageKeyAllocator::FabricNOC(fabricIndex);
	break;
	case CertChainElement::kIcac:
	return DefaultStorageKeyAllocator::FabricICAC(fabricIndex);
	break;
	case CertChainElement::kRcac:
	return DefaultStorageKeyAllocator::FabricRCAC(fabricIndex);
	break;
	default:
	break;
	}

	return StorageKeyName::Uninitialized();
	}

	bool StorageHasCertificate(PersistentStorageDelegate * storage, FabricIndex fabricIndex, CertChainElement element)
	{
	StorageKeyName storageKey = GetStorageKeyForCert(fabricIndex, element);

	if (!storageKey)
	{
	return false;
	}

	// TODO(#16958): need to actually read the cert to know if it's there due to platforms not
	// properly enforcing CHIP_ERROR_BUFFER_TOO_SMALL behavior needed by
	// PersistentStorageDelegate.
	uint8_t placeHolderCertBuffer[kMaxCHIPCertLength];

	uint16_t keySize = sizeof(placeHolderCertBuffer);
	CHIP_ERROR err = storage->SyncGetKeyValue(storageKey.KeyName(), &placeHolderCertBuffer[0], keySize);

	return (err == CHIP_NO_ERROR);
	}

	CHIP_ERROR LoadCertFromStorage(PersistentStorageDelegate * storage, FabricIndex fabricIndex, CertChainElement element,
	MutableByteSpan & outCert)
	{
	StorageKeyName storageKey = GetStorageKeyForCert(fabricIndex, element);
	if (!storageKey)
	{
	return CHIP_ERROR_INTERNAL;
	}

	uint16_t keySize = static_cast<uint16_t>(outCert.size());
	CHIP_ERROR err = storage->SyncGetKeyValue(storageKey.KeyName(), outCert.data(), keySize);

	// Not finding an ICAC means we don't have one, so adjust to meet the API contract, where
	// outCert.empty() will be true;
	if ((element == CertChainElement::kIcac) && (err == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND))
	{
	outCert.reduce_size(0);
	return CHIP_ERROR_NOT_FOUND;
	}

	if (err == CHIP_NO_ERROR)
	{
	outCert.reduce_size(keySize);
	}
	else if (err == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND)
	{
	// Convert persisted storage error to CHIP_ERROR_NOT_FOUND so that
	// `PersistentStorageOpCertStore::GetCertificate` doesn't need to convert.
	err = CHIP_ERROR_NOT_FOUND;
	}

	return err;
	}

	CHIP_ERROR SaveCertToStorage(PersistentStorageDelegate * storage, FabricIndex fabricIndex, CertChainElement element,
	const ByteSpan & cert)
	{
	StorageKeyName storageKey = GetStorageKeyForCert(fabricIndex, element);
	if (!storageKey)
	{
	return CHIP_ERROR_INTERNAL;
	}

	// If provided an empty ICAC, we delete the ICAC key previously used. If not there, it's OK
	if ((element == CertChainElement::kIcac) && (cert.empty()))
	{
	CHIP_ERROR err = storage->SyncDeleteKeyValue(storageKey.KeyName());
	if ((err == CHIP_NO_ERROR) \|\| (err == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND))
	{
	return CHIP_NO_ERROR;
	}
	return err;
	}

	return storage->SyncSetKeyValue(storageKey.KeyName(), cert.data(), static_cast<uint16_t>(cert.size()));
	}

	CHIP_ERROR DeleteCertFromStorage(PersistentStorageDelegate * storage, FabricIndex fabricIndex, CertChainElement element)
	{
	StorageKeyName storageKey = GetStorageKeyForCert(fabricIndex, element);
	if (!storageKey)
	{
	return CHIP_ERROR_INTERNAL;
	}
	return storage->SyncDeleteKeyValue(storageKey.KeyName());
	}

	} // namespace

	bool PersistentStorageOpCertStore::HasPendingRootCert() const
	{
	if (mStorage == nullptr)
	{
	return false;
	}

	return (mPendingRcac.Get() != nullptr) && mStateFlags.Has(StateFlags::kAddNewTrustedRootCalled);
	}

	bool PersistentStorageOpCertStore::HasPendingNocChain() const
	{
	if (mStorage == nullptr)
	{
	return false;
	}

	return (mPendingNoc.Get() != nullptr) && mStateFlags.HasAny(StateFlags::kAddNewOpCertsCalled, StateFlags::kUpdateOpCertsCalled);
	}

	bool PersistentStorageOpCertStore::HasCertificateForFabric(FabricIndex fabricIndex, CertChainElement element) const
	{
	if ((mStorage == nullptr) \|\| !IsValidFabricIndex(fabricIndex))
	{
	return false;
	}

	// FabricIndex matches pending, we MAY have some pending data
	if (fabricIndex == mPendingFabricIndex)
	{
	switch (element)
	{
	case CertChainElement::kRcac:
	if (mPendingRcac.Get() != nullptr)
	{
	return true;
	}
	break;
	case CertChainElement::kIcac:
	if (mPendingIcac.Get() != nullptr)
	{
	return true;
	}
	// If we have a pending NOC and no pending ICAC, don't delegate to storage, return not found here
	// since in the pending state, there truly is nothing.
	if (mPendingNoc.Get() != nullptr)
	{
	return false;
	}
	break;
	case CertChainElement::kNoc:
	if (mPendingNoc.Get() != nullptr)
	{
	return true;
	}
	break;
	default:
	return false;
	}
	}

	return StorageHasCertificate(mStorage, fabricIndex, element);
	}

	CHIP_ERROR PersistentStorageOpCertStore::AddNewTrustedRootCertForFabric(FabricIndex fabricIndex, const ByteSpan & rcac)
	{
	ReturnErrorCodeIf(mStorage == nullptr, CHIP_ERROR_INCORRECT_STATE);
	ReturnErrorCodeIf(!IsValidFabricIndex(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);
	ReturnErrorCodeIf(rcac.empty() \|\| (rcac.size() > Credentials::kMaxCHIPCertLength), CHIP_ERROR_INVALID_ARGUMENT);

	ReturnErrorCodeIf(mStateFlags.HasAny(StateFlags::kUpdateOpCertsCalled, StateFlags::kAddNewTrustedRootCalled,
	StateFlags::kAddNewOpCertsCalled),
	CHIP_ERROR_INCORRECT_STATE);
	ReturnErrorCodeIf(StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kRcac), CHIP_ERROR_INCORRECT_STATE);

	Platform::ScopedMemoryBufferWithSize<uint8_t> rcacBuf;
	ReturnErrorCodeIf(!rcacBuf.Alloc(rcac.size()), CHIP_ERROR_NO_MEMORY);
	memcpy(rcacBuf.Get(), rcac.data(), rcac.size());

	mPendingRcac = std::move(rcacBuf);

	mPendingFabricIndex = fabricIndex;
	mStateFlags.Set(StateFlags::kAddNewTrustedRootCalled);

	return CHIP_NO_ERROR;
	}

	CHIP_ERROR PersistentStorageOpCertStore::AddNewOpCertsForFabric(FabricIndex fabricIndex, const ByteSpan & noc,
	const ByteSpan & icac)
	{
	ReturnErrorCodeIf(mStorage == nullptr, CHIP_ERROR_INCORRECT_STATE);
	ReturnErrorCodeIf(!IsValidFabricIndex(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);
	ReturnErrorCodeIf(noc.empty() \|\| (noc.size() > Credentials::kMaxCHIPCertLength), CHIP_ERROR_INVALID_ARGUMENT);
	ReturnErrorCodeIf(icac.size() > Credentials::kMaxCHIPCertLength, CHIP_ERROR_INVALID_ARGUMENT);

	// Can't have called UpdateOpCertsForFabric first, or called with pending certs
	ReturnErrorCodeIf(mStateFlags.HasAny(StateFlags::kUpdateOpCertsCalled, StateFlags::kAddNewOpCertsCalled),
	CHIP_ERROR_INCORRECT_STATE);

	// Need to have trusted roots installed to make the chain valid
	ReturnErrorCodeIf(!mStateFlags.Has(StateFlags::kAddNewTrustedRootCalled), CHIP_ERROR_INCORRECT_STATE);

	// fabricIndex must match the current pending fabric
	ReturnErrorCodeIf(fabricIndex != mPendingFabricIndex, CHIP_ERROR_INVALID_FABRIC_INDEX);

	// Can't have persisted NOC/ICAC for same fabric if adding
	ReturnErrorCodeIf(StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kNoc), CHIP_ERROR_INCORRECT_STATE);
	ReturnErrorCodeIf(StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kIcac), CHIP_ERROR_INCORRECT_STATE);

	Platform::ScopedMemoryBufferWithSize<uint8_t> nocBuf;
	ReturnErrorCodeIf(!nocBuf.Alloc(noc.size()), CHIP_ERROR_NO_MEMORY);
	memcpy(nocBuf.Get(), noc.data(), noc.size());

	Platform::ScopedMemoryBufferWithSize<uint8_t> icacBuf;
	if (icac.size() > 0)
	{
	ReturnErrorCodeIf(!icacBuf.Alloc(icac.size()), CHIP_ERROR_NO_MEMORY);
	memcpy(icacBuf.Get(), icac.data(), icac.size());
	}

	mPendingNoc = std::move(nocBuf);
	mPendingIcac = std::move(icacBuf);

	mStateFlags.Set(StateFlags::kAddNewOpCertsCalled);

	return CHIP_NO_ERROR;
	}

	CHIP_ERROR PersistentStorageOpCertStore::UpdateOpCertsForFabric(FabricIndex fabricIndex, const ByteSpan & noc,
	const ByteSpan & icac)
	{
	ReturnErrorCodeIf(mStorage == nullptr, CHIP_ERROR_INCORRECT_STATE);
	ReturnErrorCodeIf(!IsValidFabricIndex(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);
	ReturnErrorCodeIf(noc.empty() \|\| (noc.size() > Credentials::kMaxCHIPCertLength), CHIP_ERROR_INVALID_ARGUMENT);
	ReturnErrorCodeIf(icac.size() > Credentials::kMaxCHIPCertLength, CHIP_ERROR_INVALID_ARGUMENT);

	// Can't have called AddNewOpCertsForFabric first, and should never get here after AddNewTrustedRootCertForFabric.
	ReturnErrorCodeIf(mStateFlags.HasAny(StateFlags::kAddNewOpCertsCalled, StateFlags::kAddNewTrustedRootCalled),
	CHIP_ERROR_INCORRECT_STATE);

	// Can't have already pending NOC from UpdateOpCerts not yet committed
	ReturnErrorCodeIf(mStateFlags.Has(StateFlags::kUpdateOpCertsCalled), CHIP_ERROR_INCORRECT_STATE);

	// Need to have trusted roots installed to make the chain valid
	ReturnErrorCodeIf(!StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kRcac), CHIP_ERROR_INCORRECT_STATE);

	// Must have persisted NOC for same fabric if updating
	ReturnErrorCodeIf(!StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kNoc), CHIP_ERROR_INCORRECT_STATE);

	// Don't check for ICAC, we may not have had one before, but assume that if NOC is there, a
	// previous chain was at least partially there

	Platform::ScopedMemoryBufferWithSize<uint8_t> nocBuf;
	ReturnErrorCodeIf(!nocBuf.Alloc(noc.size()), CHIP_ERROR_NO_MEMORY);
	memcpy(nocBuf.Get(), noc.data(), noc.size());

	Platform::ScopedMemoryBufferWithSize<uint8_t> icacBuf;
	if (icac.size() > 0)
	{
	ReturnErrorCodeIf(!icacBuf.Alloc(icac.size()), CHIP_ERROR_NO_MEMORY);
	memcpy(icacBuf.Get(), icac.data(), icac.size());
	}

	mPendingNoc = std::move(nocBuf);
	mPendingIcac = std::move(icacBuf);

	// For NOC update, UpdateOpCertsForFabric is what determines the pending fabric index,
	// not a previous AddNewTrustedRootCertForFabric call.
	mPendingFabricIndex = fabricIndex;

	mStateFlags.Set(StateFlags::kUpdateOpCertsCalled);

	return CHIP_NO_ERROR;
	}

	CHIP_ERROR PersistentStorageOpCertStore::CommitOpCertsForFabric(FabricIndex fabricIndex)
	{
	VerifyOrReturnError(mStorage != nullptr, CHIP_ERROR_INCORRECT_STATE);
	VerifyOrReturnError(IsValidFabricIndex(fabricIndex) && (fabricIndex == mPendingFabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);

	VerifyOrReturnError(HasPendingNocChain(), CHIP_ERROR_INCORRECT_STATE);
	if (HasPendingRootCert())
	{
	// Neither of these conditions should have occurred based on other interlocks, but since
	// committing certificates is a dangerous operation, we absolutely validate our assumptions.
	ReturnErrorCodeIf(mStateFlags.Has(StateFlags::kUpdateOpCertsCalled), CHIP_ERROR_INCORRECT_STATE);
	ReturnErrorCodeIf(!mStateFlags.Has(StateFlags::kAddNewTrustedRootCalled), CHIP_ERROR_INCORRECT_STATE);
	}

	// TODO: Handle transaction marking to revert partial certs at next boot if we get interrupted by reboot.

	// Start committing NOC first so we don't have dangling roots if one was added.
	ByteSpan pendingNocSpan{ mPendingNoc.Get(), mPendingNoc.AllocatedSize() };
	CHIP_ERROR nocErr = SaveCertToStorage(mStorage, mPendingFabricIndex, CertChainElement::kNoc, pendingNocSpan);

	// ICAC storage handles deleting on empty/missing
	ByteSpan pendingIcacSpan{ mPendingIcac.Get(), mPendingIcac.AllocatedSize() };
	CHIP_ERROR icacErr = SaveCertToStorage(mStorage, mPendingFabricIndex, CertChainElement::kIcac, pendingIcacSpan);

	CHIP_ERROR rcacErr = CHIP_NO_ERROR;
	if (HasPendingRootCert())
	{
	ByteSpan pendingRcacSpan{ mPendingRcac.Get(), mPendingRcac.AllocatedSize() };
	rcacErr = SaveCertToStorage(mStorage, mPendingFabricIndex, CertChainElement::kRcac, pendingRcacSpan);
	}

	// Remember which was the first error, and if any error occurred.
	CHIP_ERROR stickyErr = nocErr;
	stickyErr = (stickyErr != CHIP_NO_ERROR) ? stickyErr : icacErr;
	stickyErr = (stickyErr != CHIP_NO_ERROR) ? stickyErr : rcacErr;

	if (stickyErr != CHIP_NO_ERROR)
	{
	// On Adds rather than updates, remove anything possibly stored for the new fabric on partial
	// failure.
	if (mStateFlags.Has(StateFlags::kAddNewOpCertsCalled))
	{
	(void) DeleteCertFromStorage(mStorage, mPendingFabricIndex, CertChainElement::kNoc);
	(void) DeleteCertFromStorage(mStorage, mPendingFabricIndex, CertChainElement::kIcac);
	}
	if (mStateFlags.Has(StateFlags::kAddNewTrustedRootCalled))
	{
	(void) DeleteCertFromStorage(mStorage, mPendingFabricIndex, CertChainElement::kRcac);
	}
	if (mStateFlags.Has(StateFlags::kUpdateOpCertsCalled))
	{
	// Can't do anything to clean-up here, but pretty sure the fabric is broken now...
	// TODO: Handle transaction marking to revert certs if somehow failing store on update by pre-backing-up opcerts
	}

	return stickyErr;
	}

	// If we got here, we succeeded and can reset the pending certs: next `GetCertificate` will use the stored certs
	RevertPendingOpCerts();
	return CHIP_NO_ERROR;
	}

	bool PersistentStorageOpCertStore::HasAnyCertificateForFabric(FabricIndex fabricIndex) const
	{
	VerifyOrReturnError(IsValidFabricIndex(fabricIndex), false);

	bool rcacMissing = !StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kRcac);
	bool icacMissing = !StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kIcac);
	bool nocMissing = !StorageHasCertificate(mStorage, fabricIndex, CertChainElement::kNoc);
	bool anyPending = (mPendingRcac.Get() != nullptr) \|\| (mPendingIcac.Get() != nullptr) \|\| (mPendingNoc.Get() != nullptr);

	if (rcacMissing && icacMissing && nocMissing && !anyPending)
	{
	return false;
	}

	return true;
	}

	CHIP_ERROR PersistentStorageOpCertStore::RemoveOpCertsForFabric(FabricIndex fabricIndex)
	{
	VerifyOrReturnError(mStorage != nullptr, CHIP_ERROR_INCORRECT_STATE);
	VerifyOrReturnError(IsValidFabricIndex(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);

	// If there was no state, pending or persisted, we have an error
	ReturnErrorCodeIf(!HasAnyCertificateForFabric(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);

	// Clear any pending state
	RevertPendingOpCerts();

	// Remove all persisted certs for the given fabric, blindly
	CHIP_ERROR nocErr = DeleteCertFromStorage(mStorage, fabricIndex, CertChainElement::kNoc);
	CHIP_ERROR icacErr = DeleteCertFromStorage(mStorage, fabricIndex, CertChainElement::kIcac);
	CHIP_ERROR rcacErr = DeleteCertFromStorage(mStorage, fabricIndex, CertChainElement::kRcac);

	// Ignore missing cert errors
	nocErr = (nocErr == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND) ? CHIP_NO_ERROR : nocErr;
	icacErr = (icacErr == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND) ? CHIP_NO_ERROR : icacErr;
	rcacErr = (rcacErr == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND) ? CHIP_NO_ERROR : rcacErr;

	// Find the first error and return that
	CHIP_ERROR stickyErr = nocErr;
	stickyErr = (stickyErr != CHIP_NO_ERROR) ? stickyErr : icacErr;
	stickyErr = (stickyErr != CHIP_NO_ERROR) ? stickyErr : rcacErr;

	return stickyErr;
	}

	CHIP_ERROR PersistentStorageOpCertStore::GetPendingCertificate(FabricIndex fabricIndex, CertChainElement element,
	MutableByteSpan & outCertificate) const
	{
	if (fabricIndex != mPendingFabricIndex)
	{
	return CHIP_ERROR_NOT_FOUND;
	}

	// FabricIndex matches pending, we MAY have some pending data
	switch (element)
	{
	case CertChainElement::kRcac:
	if (mPendingRcac.Get() != nullptr)
	{
	ByteSpan rcacSpan{ mPendingRcac.Get(), mPendingRcac.AllocatedSize() };
	return CopySpanToMutableSpan(rcacSpan, outCertificate);
	}
	break;
	case CertChainElement::kIcac:
	if (mPendingIcac.Get() != nullptr)
	{
	ByteSpan icacSpan{ mPendingIcac.Get(), mPendingIcac.AllocatedSize() };
	return CopySpanToMutableSpan(icacSpan, outCertificate);
	}
	break;
	case CertChainElement::kNoc:
	if (mPendingNoc.Get() != nullptr)
	{
	ByteSpan nocSpan{ mPendingNoc.Get(), mPendingNoc.AllocatedSize() };
	return CopySpanToMutableSpan(nocSpan, outCertificate);
	}
	break;
	default:
	return CHIP_ERROR_INVALID_ARGUMENT;
	}

	return CHIP_ERROR_NOT_FOUND;
	}

	CHIP_ERROR PersistentStorageOpCertStore::GetCertificate(FabricIndex fabricIndex, CertChainElement element,
	MutableByteSpan & outCertificate) const
	{
	VerifyOrReturnError(mStorage != nullptr, CHIP_ERROR_INCORRECT_STATE);
	VerifyOrReturnError(IsValidFabricIndex(fabricIndex), CHIP_ERROR_INVALID_FABRIC_INDEX);

	// Handle case of pending data
	CHIP_ERROR err = GetPendingCertificate(fabricIndex, element, outCertificate);
	if ((err == CHIP_NO_ERROR) \|\| (err != CHIP_ERROR_NOT_FOUND))
	{
	// Found in pending, or got a deeper error: return the pending cert status.
	return err;
	}

	// If we have a pending NOC and no pending ICAC, don't delegate to storage, return not found here
	// since in the pending state, there truly is nothing.

	if ((err == CHIP_ERROR_NOT_FOUND) && (element == CertChainElement::kIcac) && (mPendingNoc.Get() != nullptr))
	{
	// Don't delegate to storage if we just have a pending NOC and are missing the ICAC
	return CHIP_ERROR_NOT_FOUND;
	}

	// Not found in pending, let's look in persisted
	return LoadCertFromStorage(mStorage, fabricIndex, element, outCertificate);
	}

	} // namespace Credentials
	} // namespace chip