blob: 16139a1f9301a314d45630ffb654806018a246de [file] [log] [blame]
/*
*
* Copyright (c) 2020-2022 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.
*/
/**
* @file
* This file implements the CHIP SPAKE2P Session object that provides
* APIs for constructing spake2p messages and establishing encryption
* keys.
*
* The protocol for handling pA, pB, cB and cA is defined in SPAKE2
* Plus specifications.
* (https://www.ietf.org/id/draft-bar-cfrg-spake2plus-01.html)
*
*/
#include <protocols/secure_channel/PASESession.h>
#include <inttypes.h>
#include <string.h>
#include <lib/core/CHIPEncoding.h>
#include <lib/core/CHIPSafeCasts.h>
#include <lib/support/BufferWriter.h>
#include <lib/support/CHIPMem.h>
#include <lib/support/CodeUtils.h>
#include <lib/support/SafeInt.h>
#include <lib/support/TypeTraits.h>
#include <protocols/Protocols.h>
#include <protocols/secure_channel/Constants.h>
#include <protocols/secure_channel/StatusReport.h>
#include <setup_payload/SetupPayload.h>
#include <system/TLVPacketBufferBackingStore.h>
#include <trace/trace.h>
#include <transport/SessionManager.h>
namespace chip {
using namespace Crypto;
using namespace Messaging;
using namespace Protocols::SecureChannel;
const char * kSpake2pContext = "CHIP PAKE V1 Commissioning";
const char * kSpake2pI2RSessionInfo = "Commissioning I2R Key";
const char * kSpake2pR2ISessionInfo = "Commissioning R2I Key";
// Amounts of time to allow for server-side processing of messages.
//
// These timeout values only allow for the server-side processing and assume that any transport-specific
// latency will be added to them.
//
// The session establishment fails if the response is not received within the resulting timeout window,
// which accounts for both transport latency and the server-side latency.
static constexpr ExchangeContext::Timeout kExpectedLowProcessingTime = System::Clock::Seconds16(2);
static constexpr ExchangeContext::Timeout kExpectedHighProcessingTime = System::Clock::Seconds16(30);
PASESession::~PASESession()
{
// Let's clear out any security state stored in the object, before destroying it.
Clear();
}
void PASESession::OnSessionReleased()
{
// Call into our super-class before we clear our state.
PairingSession::OnSessionReleased();
Clear();
}
void PASESession::Finish()
{
mPairingComplete = true;
PairingSession::Finish();
}
void PASESession::Clear()
{
// This function zeroes out and resets the memory used by the object.
// It's done so that no security related information will be leaked.
memset(&mPASEVerifier, 0, sizeof(mPASEVerifier));
memset(&mKe[0], 0, sizeof(mKe));
mNextExpectedMsg.ClearValue();
mSpake2p.Clear();
mCommissioningHash.Clear();
mIterationCount = 0;
mSaltLength = 0;
if (mSalt != nullptr)
{
chip::Platform::MemoryFree(mSalt);
mSalt = nullptr;
}
mKeLen = sizeof(mKe);
mPairingComplete = false;
PairingSession::Clear();
}
CHIP_ERROR PASESession::Init(SessionManager & sessionManager, uint32_t setupCode, SessionEstablishmentDelegate * delegate)
{
VerifyOrReturnError(delegate != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
// Reset any state maintained by PASESession object (in case it's being reused for pairing)
Clear();
ReturnErrorOnFailure(mCommissioningHash.Begin());
ReturnErrorOnFailure(mCommissioningHash.AddData(ByteSpan{ Uint8::from_const_char(kSpake2pContext), strlen(kSpake2pContext) }));
mDelegate = delegate;
ReturnErrorOnFailure(AllocateSecureSession(sessionManager));
VerifyOrReturnError(GetLocalSessionId().HasValue(), CHIP_ERROR_INCORRECT_STATE);
ChipLogDetail(SecureChannel, "Assigned local session key ID %u", GetLocalSessionId().Value());
ReturnErrorCodeIf(setupCode >= (1 << kSetupPINCodeFieldLengthInBits), CHIP_ERROR_INVALID_ARGUMENT);
mSetupPINCode = setupCode;
return CHIP_NO_ERROR;
}
CHIP_ERROR PASESession::GeneratePASEVerifier(Spake2pVerifier & verifier, uint32_t pbkdf2IterCount, const ByteSpan & salt,
bool useRandomPIN, uint32_t & setupPINCode)
{
MATTER_TRACE_EVENT_SCOPE("GeneratePASEVerifier", "PASESession");
if (useRandomPIN)
{
ReturnErrorOnFailure(DRBG_get_bytes(reinterpret_cast<uint8_t *>(&setupPINCode), sizeof(setupPINCode)));
// Passcodes shall be restricted to the values 00000001 to 99999998 in decimal, see 5.1.1.6
setupPINCode = (setupPINCode % kSetupPINCodeMaximumValue) + 1;
}
return verifier.Generate(pbkdf2IterCount, salt, setupPINCode);
}
CHIP_ERROR PASESession::SetupSpake2p()
{
MATTER_TRACE_EVENT_SCOPE("SetupSpake2p", "PASESession");
uint8_t context[kSHA256_Hash_Length] = { 0 };
MutableByteSpan contextSpan{ context };
ReturnErrorOnFailure(mCommissioningHash.Finish(contextSpan));
ReturnErrorOnFailure(mSpake2p.Init(contextSpan.data(), contextSpan.size()));
return CHIP_NO_ERROR;
}
CHIP_ERROR PASESession::WaitForPairing(SessionManager & sessionManager, const Spake2pVerifier & verifier, uint32_t pbkdf2IterCount,
const ByteSpan & salt, Optional<ReliableMessageProtocolConfig> mrpLocalConfig,
SessionEstablishmentDelegate * delegate)
{
// Return early on error here, as we have not initialized any state yet
ReturnErrorCodeIf(salt.empty(), CHIP_ERROR_INVALID_ARGUMENT);
ReturnErrorCodeIf(salt.data() == nullptr, CHIP_ERROR_INVALID_ARGUMENT);
ReturnErrorCodeIf(salt.size() < kSpake2p_Min_PBKDF_Salt_Length || salt.size() > kSpake2p_Max_PBKDF_Salt_Length,
CHIP_ERROR_INVALID_ARGUMENT);
CHIP_ERROR err = Init(sessionManager, kSetupPINCodeUndefinedValue, delegate);
// From here onwards, let's go to exit on error, as some state might have already
// been initialized
SuccessOrExit(err);
mRole = CryptoContext::SessionRole::kResponder;
VerifyOrExit(CanCastTo<uint16_t>(salt.size()), err = CHIP_ERROR_INVALID_ARGUMENT);
mSaltLength = static_cast<uint16_t>(salt.size());
if (mSalt != nullptr)
{
chip::Platform::MemoryFree(mSalt);
mSalt = nullptr;
}
mSalt = static_cast<uint8_t *>(chip::Platform::MemoryAlloc(mSaltLength));
VerifyOrExit(mSalt != nullptr, err = CHIP_ERROR_NO_MEMORY);
memmove(mSalt, salt.data(), mSaltLength);
memmove(&mPASEVerifier, &verifier, sizeof(verifier));
mIterationCount = pbkdf2IterCount;
mNextExpectedMsg.SetValue(MsgType::PBKDFParamRequest);
mPairingComplete = false;
mLocalMRPConfig = mrpLocalConfig;
ChipLogDetail(SecureChannel, "Waiting for PBKDF param request");
exit:
if (err != CHIP_NO_ERROR)
{
Clear();
}
return err;
}
CHIP_ERROR PASESession::Pair(SessionManager & sessionManager, uint32_t peerSetUpPINCode,
Optional<ReliableMessageProtocolConfig> mrpLocalConfig, Messaging::ExchangeContext * exchangeCtxt,
SessionEstablishmentDelegate * delegate)
{
MATTER_TRACE_EVENT_SCOPE("Pair", "PASESession");
ReturnErrorCodeIf(exchangeCtxt == nullptr, CHIP_ERROR_INVALID_ARGUMENT);
CHIP_ERROR err = Init(sessionManager, peerSetUpPINCode, delegate);
SuccessOrExit(err);
mRole = CryptoContext::SessionRole::kInitiator;
mExchangeCtxt = exchangeCtxt;
// When commissioning starts, the peer is assumed to be active.
mExchangeCtxt->GetSessionHandle()->AsUnauthenticatedSession()->MarkActiveRx();
mExchangeCtxt->UseSuggestedResponseTimeout(kExpectedLowProcessingTime);
mLocalMRPConfig = mrpLocalConfig;
err = SendPBKDFParamRequest();
SuccessOrExit(err);
mDelegate->OnSessionEstablishmentStarted();
exit:
if (err != CHIP_NO_ERROR)
{
Clear();
}
return err;
}
void PASESession::OnResponseTimeout(ExchangeContext * ec)
{
VerifyOrReturn(ec != nullptr, ChipLogError(SecureChannel, "PASESession::OnResponseTimeout was called by null exchange"));
VerifyOrReturn(mExchangeCtxt == nullptr || mExchangeCtxt == ec,
ChipLogError(SecureChannel, "PASESession::OnResponseTimeout exchange doesn't match"));
// If we were waiting for something, mNextExpectedMsg had better have a value.
ChipLogError(SecureChannel, "PASESession timed out while waiting for a response from the peer. Expected message type was %u",
to_underlying(mNextExpectedMsg.Value()));
// Discard the exchange so that Clear() doesn't try closing it. The
// exchange will handle that.
DiscardExchange();
Clear();
// Do this last in case the delegate frees us.
NotifySessionEstablishmentError(CHIP_ERROR_TIMEOUT);
}
CHIP_ERROR PASESession::DeriveSecureSession(CryptoContext & session) const
{
VerifyOrReturnError(mPairingComplete, CHIP_ERROR_INCORRECT_STATE);
return session.InitFromSecret(ByteSpan(mKe, mKeLen), ByteSpan(nullptr, 0),
CryptoContext::SessionInfoType::kSessionEstablishment, mRole);
}
CHIP_ERROR PASESession::SendPBKDFParamRequest()
{
MATTER_TRACE_EVENT_SCOPE("SendPBKDFParamRequest", "PASESession");
VerifyOrReturnError(GetLocalSessionId().HasValue(), CHIP_ERROR_INCORRECT_STATE);
ReturnErrorOnFailure(DRBG_get_bytes(mPBKDFLocalRandomData, sizeof(mPBKDFLocalRandomData)));
const size_t mrpParamsSize = mLocalMRPConfig.HasValue() ? TLV::EstimateStructOverhead(sizeof(uint16_t), sizeof(uint16_t)) : 0;
const size_t max_msg_len = TLV::EstimateStructOverhead(kPBKDFParamRandomNumberSize, // initiatorRandom,
sizeof(uint16_t), // initiatorSessionId
sizeof(PasscodeId), // passcodeId,
sizeof(uint8_t), // hasPBKDFParameters
mrpParamsSize // MRP Parameters
);
System::PacketBufferHandle req = System::PacketBufferHandle::New(max_msg_len);
VerifyOrReturnError(!req.IsNull(), CHIP_ERROR_NO_MEMORY);
System::PacketBufferTLVWriter tlvWriter;
tlvWriter.Init(std::move(req));
TLV::TLVType outerContainerType = TLV::kTLVType_NotSpecified;
ReturnErrorOnFailure(tlvWriter.StartContainer(TLV::AnonymousTag(), TLV::kTLVType_Structure, outerContainerType));
ReturnErrorOnFailure(tlvWriter.PutBytes(TLV::ContextTag(1), mPBKDFLocalRandomData, sizeof(mPBKDFLocalRandomData)));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(2), GetLocalSessionId().Value()));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(3), kDefaultCommissioningPasscodeId));
ReturnErrorOnFailure(tlvWriter.PutBoolean(TLV::ContextTag(4), mHavePBKDFParameters));
if (mLocalMRPConfig.HasValue())
{
ChipLogDetail(SecureChannel, "Including MRP parameters in PBKDF param request");
ReturnErrorOnFailure(EncodeMRPParameters(TLV::ContextTag(5), mLocalMRPConfig.Value(), tlvWriter));
}
ReturnErrorOnFailure(tlvWriter.EndContainer(outerContainerType));
ReturnErrorOnFailure(tlvWriter.Finalize(&req));
// Update commissioning hash with the pbkdf2 param request that's being sent.
ReturnErrorOnFailure(mCommissioningHash.AddData(ByteSpan{ req->Start(), req->DataLength() }));
ReturnErrorOnFailure(
mExchangeCtxt->SendMessage(MsgType::PBKDFParamRequest, std::move(req), SendFlags(SendMessageFlags::kExpectResponse)));
mNextExpectedMsg.SetValue(MsgType::PBKDFParamResponse);
ChipLogDetail(SecureChannel, "Sent PBKDF param request");
return CHIP_NO_ERROR;
}
CHIP_ERROR PASESession::HandlePBKDFParamRequest(System::PacketBufferHandle && msg)
{
MATTER_TRACE_EVENT_SCOPE("HandlePBKDFParamRequest", "PASESession");
CHIP_ERROR err = CHIP_NO_ERROR;
System::PacketBufferTLVReader tlvReader;
TLV::TLVType containerType = TLV::kTLVType_Structure;
uint16_t initiatorSessionId;
uint8_t initiatorRandom[kPBKDFParamRandomNumberSize];
uint32_t decodeTagIdSeq = 0;
PasscodeId passcodeId = kDefaultCommissioningPasscodeId;
bool hasPBKDFParameters = false;
ChipLogDetail(SecureChannel, "Received PBKDF param request");
SuccessOrExit(err = mCommissioningHash.AddData(ByteSpan{ msg->Start(), msg->DataLength() }));
tlvReader.Init(std::move(msg));
SuccessOrExit(err = tlvReader.Next(containerType, TLV::AnonymousTag()));
SuccessOrExit(err = tlvReader.EnterContainer(containerType));
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
SuccessOrExit(err = tlvReader.GetBytes(initiatorRandom, sizeof(initiatorRandom)));
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
SuccessOrExit(err = tlvReader.Get(initiatorSessionId));
ChipLogDetail(SecureChannel, "Peer assigned session ID %d", initiatorSessionId);
SetPeerSessionId(initiatorSessionId);
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
SuccessOrExit(err = tlvReader.Get(passcodeId));
VerifyOrExit(passcodeId == kDefaultCommissioningPasscodeId, err = CHIP_ERROR_INVALID_PASE_PARAMETER);
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
SuccessOrExit(err = tlvReader.Get(hasPBKDFParameters));
if (tlvReader.Next() != CHIP_END_OF_TLV)
{
SuccessOrExit(err = DecodeMRPParametersIfPresent(TLV::ContextTag(5), tlvReader));
mExchangeCtxt->GetSessionHandle()->AsUnauthenticatedSession()->SetRemoteMRPConfig(mRemoteMRPConfig);
}
err = SendPBKDFParamResponse(ByteSpan(initiatorRandom), hasPBKDFParameters);
SuccessOrExit(err);
mDelegate->OnSessionEstablishmentStarted();
exit:
if (err != CHIP_NO_ERROR)
{
SendStatusReport(mExchangeCtxt, kProtocolCodeInvalidParam);
}
return err;
}
CHIP_ERROR PASESession::SendPBKDFParamResponse(ByteSpan initiatorRandom, bool initiatorHasPBKDFParams)
{
MATTER_TRACE_EVENT_SCOPE("SendPBKDFParamResponse", "PASESession");
VerifyOrReturnError(GetLocalSessionId().HasValue(), CHIP_ERROR_INCORRECT_STATE);
ReturnErrorOnFailure(DRBG_get_bytes(mPBKDFLocalRandomData, sizeof(mPBKDFLocalRandomData)));
const size_t mrpParamsSize = mLocalMRPConfig.HasValue() ? TLV::EstimateStructOverhead(sizeof(uint16_t), sizeof(uint16_t)) : 0;
const size_t max_msg_len =
TLV::EstimateStructOverhead(kPBKDFParamRandomNumberSize, // initiatorRandom
kPBKDFParamRandomNumberSize, // responderRandom
sizeof(uint16_t), // responderSessionId
TLV::EstimateStructOverhead(sizeof(uint32_t), mSaltLength), // pbkdf_parameters
mrpParamsSize // MRP Parameters
);
System::PacketBufferHandle resp = System::PacketBufferHandle::New(max_msg_len);
VerifyOrReturnError(!resp.IsNull(), CHIP_ERROR_NO_MEMORY);
System::PacketBufferTLVWriter tlvWriter;
tlvWriter.Init(std::move(resp));
TLV::TLVType outerContainerType = TLV::kTLVType_NotSpecified;
ReturnErrorOnFailure(tlvWriter.StartContainer(TLV::AnonymousTag(), TLV::kTLVType_Structure, outerContainerType));
// The initiator random value is being sent back in the response as required by the specifications
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(1), initiatorRandom));
ReturnErrorOnFailure(tlvWriter.PutBytes(TLV::ContextTag(2), mPBKDFLocalRandomData, sizeof(mPBKDFLocalRandomData)));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(3), GetLocalSessionId().Value()));
if (!initiatorHasPBKDFParams)
{
TLV::TLVType pbkdfParamContainer;
ReturnErrorOnFailure(tlvWriter.StartContainer(TLV::ContextTag(4), TLV::kTLVType_Structure, pbkdfParamContainer));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(1), mIterationCount));
ReturnErrorOnFailure(tlvWriter.PutBytes(TLV::ContextTag(2), mSalt, mSaltLength));
ReturnErrorOnFailure(tlvWriter.EndContainer(pbkdfParamContainer));
}
if (mLocalMRPConfig.HasValue())
{
ChipLogDetail(SecureChannel, "Including MRP parameters in PBKDF param response");
ReturnErrorOnFailure(EncodeMRPParameters(TLV::ContextTag(5), mLocalMRPConfig.Value(), tlvWriter));
}
ReturnErrorOnFailure(tlvWriter.EndContainer(outerContainerType));
ReturnErrorOnFailure(tlvWriter.Finalize(&resp));
// Update commissioning hash with the pbkdf2 param response that's being sent.
ReturnErrorOnFailure(mCommissioningHash.AddData(ByteSpan{ resp->Start(), resp->DataLength() }));
ReturnErrorOnFailure(SetupSpake2p());
ReturnErrorOnFailure(
mExchangeCtxt->SendMessage(MsgType::PBKDFParamResponse, std::move(resp), SendFlags(SendMessageFlags::kExpectResponse)));
ChipLogDetail(SecureChannel, "Sent PBKDF param response");
mNextExpectedMsg.SetValue(MsgType::PASE_Pake1);
return CHIP_NO_ERROR;
}
CHIP_ERROR PASESession::HandlePBKDFParamResponse(System::PacketBufferHandle && msg)
{
MATTER_TRACE_EVENT_SCOPE("HandlePBKDFParamResponse", "PASESession");
CHIP_ERROR err = CHIP_NO_ERROR;
System::PacketBufferTLVReader tlvReader;
TLV::TLVType containerType = TLV::kTLVType_Structure;
uint16_t responderSessionId;
uint8_t random[kPBKDFParamRandomNumberSize];
uint32_t decodeTagIdSeq = 0;
ByteSpan salt;
uint8_t serializedWS[kSpake2p_WS_Length * 2] = { 0 };
ChipLogDetail(SecureChannel, "Received PBKDF param response");
SuccessOrExit(err = mCommissioningHash.AddData(ByteSpan{ msg->Start(), msg->DataLength() }));
tlvReader.Init(std::move(msg));
SuccessOrExit(err = tlvReader.Next(containerType, TLV::AnonymousTag()));
SuccessOrExit(err = tlvReader.EnterContainer(containerType));
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
// Initiator's random value
SuccessOrExit(err = tlvReader.GetBytes(random, sizeof(random)));
VerifyOrExit(ByteSpan(random).data_equal(ByteSpan(mPBKDFLocalRandomData)), err = CHIP_ERROR_INVALID_PASE_PARAMETER);
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
// Responder's random value
SuccessOrExit(err = tlvReader.GetBytes(random, sizeof(random)));
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
SuccessOrExit(err = tlvReader.Get(responderSessionId));
ChipLogDetail(SecureChannel, "Peer assigned session ID %d", responderSessionId);
SetPeerSessionId(responderSessionId);
if (mHavePBKDFParameters)
{
if (tlvReader.Next() != CHIP_END_OF_TLV)
{
SuccessOrExit(err = DecodeMRPParametersIfPresent(TLV::ContextTag(5), tlvReader));
mExchangeCtxt->GetSessionHandle()->AsUnauthenticatedSession()->SetRemoteMRPConfig(mRemoteMRPConfig);
}
// TODO - Add a unit test that exercises mHavePBKDFParameters path
salt = ByteSpan(mSalt, mSaltLength);
}
else
{
SuccessOrExit(err = tlvReader.Next());
SuccessOrExit(err = tlvReader.EnterContainer(containerType));
decodeTagIdSeq = 0;
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
SuccessOrExit(err = tlvReader.Get(mIterationCount));
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
SuccessOrExit(err = tlvReader.Get(salt));
SuccessOrExit(err = tlvReader.ExitContainer(containerType));
if (tlvReader.Next() != CHIP_END_OF_TLV)
{
SuccessOrExit(err = DecodeMRPParametersIfPresent(TLV::ContextTag(5), tlvReader));
mExchangeCtxt->GetSessionHandle()->AsUnauthenticatedSession()->SetRemoteMRPConfig(mRemoteMRPConfig);
}
}
err = SetupSpake2p();
SuccessOrExit(err);
err = Spake2pVerifier::ComputeWS(mIterationCount, salt, mSetupPINCode, serializedWS, sizeof(serializedWS));
SuccessOrExit(err);
err = mSpake2p.BeginProver(nullptr, 0, nullptr, 0, &serializedWS[0], kSpake2p_WS_Length, &serializedWS[kSpake2p_WS_Length],
kSpake2p_WS_Length);
SuccessOrExit(err);
err = SendMsg1();
SuccessOrExit(err);
exit:
if (err != CHIP_NO_ERROR)
{
SendStatusReport(mExchangeCtxt, kProtocolCodeInvalidParam);
}
return err;
}
CHIP_ERROR PASESession::SendMsg1()
{
MATTER_TRACE_EVENT_SCOPE("SendMsg1", "PASESession");
const size_t max_msg_len = TLV::EstimateStructOverhead(kMAX_Point_Length);
System::PacketBufferHandle msg = System::PacketBufferHandle::New(max_msg_len);
VerifyOrReturnError(!msg.IsNull(), CHIP_ERROR_NO_MEMORY);
System::PacketBufferTLVWriter tlvWriter;
tlvWriter.Init(std::move(msg));
TLV::TLVType outerContainerType = TLV::kTLVType_NotSpecified;
ReturnErrorOnFailure(tlvWriter.StartContainer(TLV::AnonymousTag(), TLV::kTLVType_Structure, outerContainerType));
uint8_t X[kMAX_Point_Length];
size_t X_len = sizeof(X);
constexpr uint8_t kPake1_pA = 1;
ReturnErrorOnFailure(mSpake2p.ComputeRoundOne(nullptr, 0, X, &X_len));
VerifyOrReturnError(X_len == sizeof(X), CHIP_ERROR_INTERNAL);
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kPake1_pA), ByteSpan(X)));
ReturnErrorOnFailure(tlvWriter.EndContainer(outerContainerType));
ReturnErrorOnFailure(tlvWriter.Finalize(&msg));
ReturnErrorOnFailure(
mExchangeCtxt->SendMessage(MsgType::PASE_Pake1, std::move(msg), SendFlags(SendMessageFlags::kExpectResponse)));
ChipLogDetail(SecureChannel, "Sent spake2p msg1");
mNextExpectedMsg.SetValue(MsgType::PASE_Pake2);
return CHIP_NO_ERROR;
}
CHIP_ERROR PASESession::HandleMsg1_and_SendMsg2(System::PacketBufferHandle && msg1)
{
MATTER_TRACE_EVENT_SCOPE("HandleMsg1_and_SendMsg2", "PASESession");
CHIP_ERROR err = CHIP_NO_ERROR;
uint8_t Y[kMAX_Point_Length];
size_t Y_len = sizeof(Y);
uint8_t verifier[kMAX_Hash_Length];
size_t verifier_len = kMAX_Hash_Length;
ChipLogDetail(SecureChannel, "Received spake2p msg1");
System::PacketBufferTLVReader tlvReader;
TLV::TLVType containerType = TLV::kTLVType_Structure;
const uint8_t * X;
size_t X_len = 0;
tlvReader.Init(std::move(msg1));
SuccessOrExit(err = tlvReader.Next(containerType, TLV::AnonymousTag()));
SuccessOrExit(err = tlvReader.EnterContainer(containerType));
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == 1, err = CHIP_ERROR_INVALID_TLV_TAG);
X_len = tlvReader.GetLength();
SuccessOrExit(err = tlvReader.GetDataPtr(X));
SuccessOrExit(err = mSpake2p.BeginVerifier(nullptr, 0, nullptr, 0, mPASEVerifier.mW0, kP256_FE_Length, mPASEVerifier.mL,
kP256_Point_Length));
SuccessOrExit(err = mSpake2p.ComputeRoundOne(X, X_len, Y, &Y_len));
VerifyOrReturnError(Y_len == sizeof(Y), CHIP_ERROR_INTERNAL);
SuccessOrExit(err = mSpake2p.ComputeRoundTwo(X, X_len, verifier, &verifier_len));
msg1 = nullptr;
{
const size_t max_msg_len = TLV::EstimateStructOverhead(Y_len, verifier_len);
constexpr uint8_t kPake2_pB = 1;
constexpr uint8_t kPake2_cB = 2;
System::PacketBufferHandle msg2 = System::PacketBufferHandle::New(max_msg_len);
VerifyOrExit(!msg2.IsNull(), err = CHIP_ERROR_NO_MEMORY);
System::PacketBufferTLVWriter tlvWriter;
tlvWriter.Init(std::move(msg2));
TLV::TLVType outerContainerType = TLV::kTLVType_NotSpecified;
SuccessOrExit(err = tlvWriter.StartContainer(TLV::AnonymousTag(), TLV::kTLVType_Structure, outerContainerType));
SuccessOrExit(err = tlvWriter.Put(TLV::ContextTag(kPake2_pB), ByteSpan(Y)));
SuccessOrExit(err = tlvWriter.Put(TLV::ContextTag(kPake2_cB), ByteSpan(verifier, verifier_len)));
SuccessOrExit(err = tlvWriter.EndContainer(outerContainerType));
SuccessOrExit(err = tlvWriter.Finalize(&msg2));
err = mExchangeCtxt->SendMessage(MsgType::PASE_Pake2, std::move(msg2), SendFlags(SendMessageFlags::kExpectResponse));
SuccessOrExit(err);
mNextExpectedMsg.SetValue(MsgType::PASE_Pake3);
}
ChipLogDetail(SecureChannel, "Sent spake2p msg2");
exit:
if (err != CHIP_NO_ERROR)
{
SendStatusReport(mExchangeCtxt, kProtocolCodeInvalidParam);
}
return err;
}
CHIP_ERROR PASESession::HandleMsg2_and_SendMsg3(System::PacketBufferHandle && msg2)
{
MATTER_TRACE_EVENT_SCOPE("HandleMsg2_and_SendMsg3", "PASESession");
CHIP_ERROR err = CHIP_NO_ERROR;
uint8_t verifier[kMAX_Hash_Length];
size_t verifier_len = kMAX_Hash_Length;
System::PacketBufferHandle resp;
ChipLogDetail(SecureChannel, "Received spake2p msg2");
System::PacketBufferTLVReader tlvReader;
TLV::TLVType containerType = TLV::kTLVType_Structure;
const uint8_t * Y;
size_t Y_len = 0;
const uint8_t * peer_verifier;
size_t peer_verifier_len = 0;
uint32_t decodeTagIdSeq = 0;
tlvReader.Init(std::move(msg2));
SuccessOrExit(err = tlvReader.Next(containerType, TLV::AnonymousTag()));
SuccessOrExit(err = tlvReader.EnterContainer(containerType));
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
Y_len = tlvReader.GetLength();
SuccessOrExit(err = tlvReader.GetDataPtr(Y));
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == ++decodeTagIdSeq, err = CHIP_ERROR_INVALID_TLV_TAG);
peer_verifier_len = tlvReader.GetLength();
SuccessOrExit(err = tlvReader.GetDataPtr(peer_verifier));
SuccessOrExit(err = mSpake2p.ComputeRoundTwo(Y, Y_len, verifier, &verifier_len));
SuccessOrExit(err = mSpake2p.KeyConfirm(peer_verifier, peer_verifier_len));
SuccessOrExit(err = mSpake2p.GetKeys(mKe, &mKeLen));
msg2 = nullptr;
{
const size_t max_msg_len = TLV::EstimateStructOverhead(verifier_len);
constexpr uint8_t kPake3_cB = 1;
System::PacketBufferHandle msg3 = System::PacketBufferHandle::New(max_msg_len);
VerifyOrExit(!msg3.IsNull(), err = CHIP_ERROR_NO_MEMORY);
System::PacketBufferTLVWriter tlvWriter;
tlvWriter.Init(std::move(msg3));
TLV::TLVType outerContainerType = TLV::kTLVType_NotSpecified;
SuccessOrExit(err = tlvWriter.StartContainer(TLV::AnonymousTag(), TLV::kTLVType_Structure, outerContainerType));
SuccessOrExit(err = tlvWriter.Put(TLV::ContextTag(kPake3_cB), ByteSpan(verifier, verifier_len)));
SuccessOrExit(err = tlvWriter.EndContainer(outerContainerType));
SuccessOrExit(err = tlvWriter.Finalize(&msg3));
err = mExchangeCtxt->SendMessage(MsgType::PASE_Pake3, std::move(msg3), SendFlags(SendMessageFlags::kExpectResponse));
SuccessOrExit(err);
mNextExpectedMsg.SetValue(MsgType::StatusReport);
}
ChipLogDetail(SecureChannel, "Sent spake2p msg3");
exit:
if (err != CHIP_NO_ERROR)
{
SendStatusReport(mExchangeCtxt, kProtocolCodeInvalidParam);
}
return err;
}
CHIP_ERROR PASESession::HandleMsg3(System::PacketBufferHandle && msg)
{
MATTER_TRACE_EVENT_SCOPE("HandleMsg3", "PASESession");
CHIP_ERROR err = CHIP_NO_ERROR;
ChipLogDetail(SecureChannel, "Received spake2p msg3");
mNextExpectedMsg.ClearValue();
System::PacketBufferTLVReader tlvReader;
TLV::TLVType containerType = TLV::kTLVType_Structure;
const uint8_t * peer_verifier;
size_t peer_verifier_len = 0;
tlvReader.Init(std::move(msg));
SuccessOrExit(err = tlvReader.Next(containerType, TLV::AnonymousTag()));
SuccessOrExit(err = tlvReader.EnterContainer(containerType));
SuccessOrExit(err = tlvReader.Next());
VerifyOrExit(TLV::TagNumFromTag(tlvReader.GetTag()) == 1, err = CHIP_ERROR_INVALID_TLV_TAG);
peer_verifier_len = tlvReader.GetLength();
SuccessOrExit(err = tlvReader.GetDataPtr(peer_verifier));
VerifyOrExit(peer_verifier_len == kMAX_Hash_Length, err = CHIP_ERROR_INVALID_MESSAGE_LENGTH);
SuccessOrExit(err = mSpake2p.KeyConfirm(peer_verifier, peer_verifier_len));
SuccessOrExit(err = mSpake2p.GetKeys(mKe, &mKeLen));
// Send confirmation to peer that we succeeded so they can start using the session.
SendStatusReport(mExchangeCtxt, kProtocolCodeSuccess);
Finish();
exit:
if (err != CHIP_NO_ERROR)
{
SendStatusReport(mExchangeCtxt, kProtocolCodeInvalidParam);
}
return err;
}
void PASESession::OnSuccessStatusReport()
{
Finish();
}
CHIP_ERROR PASESession::OnFailureStatusReport(Protocols::SecureChannel::GeneralStatusCode generalCode, uint16_t protocolCode)
{
CHIP_ERROR err = CHIP_NO_ERROR;
switch (protocolCode)
{
case kProtocolCodeInvalidParam:
err = CHIP_ERROR_INVALID_PASE_PARAMETER;
break;
default:
err = CHIP_ERROR_INTERNAL;
break;
};
ChipLogError(SecureChannel, "Received error (protocol code %d) during PASE process: %" CHIP_ERROR_FORMAT, protocolCode,
err.Format());
return err;
}
CHIP_ERROR PASESession::ValidateReceivedMessage(ExchangeContext * exchange, const PayloadHeader & payloadHeader,
const System::PacketBufferHandle & msg)
{
VerifyOrReturnError(exchange != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
// mExchangeCtxt can be nullptr if this is the first message (PBKDFParamRequest) received by PASESession
// via UnsolicitedMessageHandler. The exchange context is allocated by exchange manager and provided
// to the handler (PASESession object).
if (mExchangeCtxt != nullptr)
{
if (mExchangeCtxt != exchange)
{
ReturnErrorOnFailure(CHIP_ERROR_INVALID_ARGUMENT);
}
}
else
{
mExchangeCtxt = exchange;
}
mExchangeCtxt->UseSuggestedResponseTimeout(kExpectedHighProcessingTime);
VerifyOrReturnError(!msg.IsNull(), CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError((mNextExpectedMsg.HasValue() && payloadHeader.HasMessageType(mNextExpectedMsg.Value())) ||
payloadHeader.HasMessageType(MsgType::StatusReport),
CHIP_ERROR_INVALID_MESSAGE_TYPE);
return CHIP_NO_ERROR;
}
CHIP_ERROR PASESession::OnUnsolicitedMessageReceived(const PayloadHeader & payloadHeader, ExchangeDelegate *& newDelegate)
{
// Handle messages by myself
newDelegate = this;
return CHIP_NO_ERROR;
}
CHIP_ERROR PASESession::OnMessageReceived(ExchangeContext * exchange, const PayloadHeader & payloadHeader,
System::PacketBufferHandle && msg)
{
CHIP_ERROR err = ValidateReceivedMessage(exchange, payloadHeader, msg);
MsgType msgType = static_cast<MsgType>(payloadHeader.GetMessageType());
SuccessOrExit(err);
#if CHIP_CONFIG_SLOW_CRYPTO
if (msgType == MsgType::PBKDFParamRequest || msgType == MsgType::PBKDFParamResponse || msgType == MsgType::PASE_Pake1 ||
msgType == MsgType::PASE_Pake2 || msgType == MsgType::PASE_Pake3)
{
SuccessOrExit(mExchangeCtxt->FlushAcks());
}
#endif // CHIP_CONFIG_SLOW_CRYPTO
switch (msgType)
{
case MsgType::PBKDFParamRequest:
err = HandlePBKDFParamRequest(std::move(msg));
break;
case MsgType::PBKDFParamResponse:
err = HandlePBKDFParamResponse(std::move(msg));
break;
case MsgType::PASE_Pake1:
err = HandleMsg1_and_SendMsg2(std::move(msg));
break;
case MsgType::PASE_Pake2:
err = HandleMsg2_and_SendMsg3(std::move(msg));
break;
case MsgType::PASE_Pake3:
err = HandleMsg3(std::move(msg));
break;
case MsgType::StatusReport:
err =
HandleStatusReport(std::move(msg), mNextExpectedMsg.HasValue() && (mNextExpectedMsg.Value() == MsgType::StatusReport));
break;
default:
err = CHIP_ERROR_INVALID_MESSAGE_TYPE;
break;
};
exit:
// Call delegate to indicate pairing failure
if (err != CHIP_NO_ERROR)
{
// Discard the exchange so that Clear() doesn't try closing it. The
// exchange will handle that.
DiscardExchange();
Clear();
ChipLogError(SecureChannel, "Failed during PASE session setup: %" CHIP_ERROR_FORMAT, err.Format());
// Do this last in case the delegate frees us.
NotifySessionEstablishmentError(err);
}
return err;
}
} // namespace chip