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@Alami-Amine
Alami-Amine committed Dec 2, 2024
1 parent 13a8f48 commit 224a626
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Showing 3 changed files with 58 additions and 43 deletions.
67 changes: 32 additions & 35 deletions src/protocols/secure_channel/CASESession.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -770,7 +770,7 @@ CHIP_ERROR CASESession::SendSigma1()
System::PacketBufferHandle msg_R1;
uint8_t destinationIdentifier[kSHA256_Hash_Length] = { 0 };

Sigma1Param encodeSigma1Params;
EncodeSigma1Param encodeSigma1Params;

// Lookup fabric info.
const auto * fabricInfo = mFabricsTable->FindFabricWithIndex(mFabricIndex);
Expand All @@ -784,9 +784,11 @@ CHIP_ERROR CASESession::SendSigma1()
mEphemeralKey = mFabricsTable->AllocateEphemeralKeypairForCASE();
VerifyOrReturnError(mEphemeralKey != nullptr, CHIP_ERROR_NO_MEMORY);
ReturnErrorOnFailure(mEphemeralKey->Initialize(ECPKeyTarget::ECDH));
encodeSigma1Params.pEphPubKey = &mEphemeralKey->Pubkey();

// Fill in the random value
ReturnErrorOnFailure(DRBG_get_bytes(mInitiatorRandom, sizeof(mInitiatorRandom)));
encodeSigma1Params.initiatorRandom = ByteSpan(mInitiatorRandom);

// Generate a Destination Identifier based on the node we are attempting to reach
{
Expand All @@ -800,15 +802,15 @@ CHIP_ERROR CASESession::SendSigma1()
Credentials::P256PublicKeySpan rootPubKeySpan{ rootPubKey.ConstBytes() };

MutableByteSpan destinationIdSpan(destinationIdentifier);
ReturnErrorOnFailure(GenerateCaseDestinationId(ByteSpan(mIPK), ByteSpan(mInitiatorRandom), rootPubKeySpan, fabricId,
ReturnErrorOnFailure(GenerateCaseDestinationId(ByteSpan(mIPK), encodeSigma1Params.initiatorRandom, rootPubKeySpan, fabricId,
mPeerNodeId, destinationIdSpan));
encodeSigma1Params.destinationId = destinationIdSpan;
}

VerifyOrReturnError(mLocalMRPConfig.HasValue(), CHIP_ERROR_INCORRECT_STATE);
encodeSigma1Params.initiatorMrpConfig = &mLocalMRPConfig.Value();

// Try to find persistent session, and resume it.
bool resuming = false;
if (mSessionResumptionStorage != nullptr)
{
CHIP_ERROR err = mSessionResumptionStorage->FindByScopedNodeId(fabricInfo->GetScopedNodeIdForNode(mPeerNodeId),
Expand All @@ -817,14 +819,13 @@ CHIP_ERROR CASESession::SendSigma1()
{
// Found valid resumption state, try to resume the session.

encodeSigma1Params.resumptionId = mResumeResumptionId;
MutableByteSpan resumeMICSpan(encodeSigma1Params.initiatorResume1MIC);
ReturnErrorOnFailure(GenerateSigmaResumeMIC(ByteSpan(mInitiatorRandom), ByteSpan(mResumeResumptionId),
ReturnErrorOnFailure(GenerateSigmaResumeMIC(encodeSigma1Params.initiatorRandom, encodeSigma1Params.resumptionId,
ByteSpan(kKDFS1RKeyInfo), ByteSpan(kResume1MIC_Nonce), resumeMICSpan));

encodeSigma1Params.initiatorResumeMICSpan = resumeMICSpan;
encodeSigma1Params.sessionResumptionRequested = true;

resuming = true;
}
}

Expand All @@ -837,7 +838,7 @@ CHIP_ERROR CASESession::SendSigma1()
ReturnErrorOnFailure(mExchangeCtxt.Value()->SendMessage(Protocols::SecureChannel::MsgType::CASE_Sigma1, std::move(msg_R1),
SendFlags(SendMessageFlags::kExpectResponse)));

if (resuming)
if (encodeSigma1Params.sessionResumptionRequested)
{
mState = State::kSentSigma1Resume;

Expand All @@ -861,17 +862,19 @@ CHIP_ERROR CASESession::SendSigma1()
return CHIP_NO_ERROR;
}

CHIP_ERROR CASESession::EncodeSigma1(System::PacketBufferHandle & msg, Sigma1Param & inputParams)
CHIP_ERROR CASESession::EncodeSigma1(System::PacketBufferHandle & msg, EncodeSigma1Param & input)
{

MATTER_TRACE_SCOPE("EncodeSigma1", "CASESession");

size_t data_len = TLV::EstimateStructOverhead(kSigmaParamRandomNumberSize, // initiatorRandom
sizeof(uint16_t), // initiatorSessionId,
kSHA256_Hash_Length, // destinationId
kP256_PublicKey_Length, // InitiatorEphPubKey,
SessionParameters::kEstimatedTLVSize, // initiatorSessionParams
SessionResumptionStorage::kResumptionIdSize, CHIP_CRYPTO_AEAD_MIC_LENGTH_BYTES);
size_t data_len = TLV::EstimateStructOverhead(kSigmaParamRandomNumberSize, // initiatorRandom
sizeof(uint16_t), // initiatorSessionId,
kSHA256_Hash_Length, // destinationId
kP256_PublicKey_Length, // InitiatorEphPubKey,
SessionParameters::kEstimatedTLVSize, // initiatorSessionParams
SessionResumptionStorage::kResumptionIdSize, // resumptionId
CHIP_CRYPTO_AEAD_MIC_LENGTH_BYTES // initiatorResumeMIC
);

msg = System::PacketBufferHandle::New(data_len);
VerifyOrReturnError(!msg.IsNull(), CHIP_ERROR_NO_MEMORY);
Expand All @@ -881,24 +884,21 @@ CHIP_ERROR CASESession::EncodeSigma1(System::PacketBufferHandle & msg, Sigma1Par

tlvWriter.Init(std::move(msg));
ReturnErrorOnFailure(tlvWriter.StartContainer(TLV::AnonymousTag(), TLV::kTLVType_Structure, outerContainerType));
// TODO Pass this in the struct?
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kInitiatorRandomTag), ByteSpan(mInitiatorRandom)));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kInitiatorSessionIdTag), inputParams.initiatorSessionId));

ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kDestinationIdTag), inputParams.destinationId));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kInitiatorRandomTag), input.initiatorRandom));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kInitiatorSessionIdTag), input.initiatorSessionId));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kDestinationIdTag), input.destinationId));

// TODO Pass this in the struct?
ReturnErrorOnFailure(tlvWriter.PutBytes(TLV::ContextTag(kInitiatorPubKeyTag), mEphemeralKey->Pubkey(),
static_cast<uint32_t>(mEphemeralKey->Pubkey().Length())));
VerifyOrReturnError(input.pEphPubKey != nullptr, CHIP_ERROR_INCORRECT_STATE);
ReturnErrorOnFailure(tlvWriter.PutBytes(TLV::ContextTag(kInitiatorPubKeyTag), *input.pEphPubKey,
static_cast<uint32_t>(input.pEphPubKey->Length())));

// TODO is it redudunt?
VerifyOrReturnError(mLocalMRPConfig.HasValue(), CHIP_ERROR_INCORRECT_STATE);
ReturnErrorOnFailure(EncodeSessionParameters(TLV::ContextTag(kInitiatorMRPParamsTag), mLocalMRPConfig.Value(), tlvWriter));
VerifyOrReturnError(input.initiatorMrpConfig != nullptr, CHIP_ERROR_INCORRECT_STATE);
ReturnErrorOnFailure(EncodeSessionParameters(TLV::ContextTag(kInitiatorMRPParamsTag), *input.initiatorMrpConfig, tlvWriter));

if (inputParams.sessionResumptionRequested)
if (input.sessionResumptionRequested)
{
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kResumptionIDTag), mResumeResumptionId));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kResume1MICTag), inputParams.initiatorResumeMICSpan));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kResumptionIDTag), input.resumptionId));
ReturnErrorOnFailure(tlvWriter.Put(TLV::ContextTag(kResume1MICTag), input.initiatorResumeMICSpan));
}

ReturnErrorOnFailure(tlvWriter.EndContainer(outerContainerType));
Expand Down Expand Up @@ -1003,7 +1003,7 @@ CHIP_ERROR CASESession::HandleSigma1(System::PacketBufferHandle && msg)
CHIP_ERROR err = CHIP_NO_ERROR;
System::PacketBufferTLVReader tlvReader;

Sigma1Param parsedSigma1;
ParseSigma1Param parsedSigma1;

SuccessOrExit(err = mCommissioningHash.AddData(ByteSpan{ msg->Start(), msg->DataLength() }));

Expand All @@ -1016,11 +1016,8 @@ CHIP_ERROR CASESession::HandleSigma1(System::PacketBufferHandle && msg)

VerifyOrExit(mFabricsTable != nullptr, err = CHIP_ERROR_INCORRECT_STATE);

// TODO: Added by Amine, taken from inside ParseSigma1
// This was removed to remove the non-parsing parts from ParseSigma1, decoupling it from higher levels
// TODO: Should i change it?
// Set the recieved MRP parameters included with Sigma1
if (parsedSigma1.InitiatorMRPParamsPresent == true)
// Set the MRP parameters provided in the Sigma1 message
if (parsedSigma1.InitiatorMRPParamsPresent)
{
mExchangeCtxt.Value()->GetSessionHandle()->AsUnauthenticatedSession()->SetRemoteSessionParameters(
GetRemoteSessionParameters());
Expand Down Expand Up @@ -2191,7 +2188,7 @@ CHIP_ERROR CASESession::OnFailureStatusReport(Protocols::SecureChannel::GeneralS
return err;
}

CHIP_ERROR CASESession::ParseSigma1(TLV::ContiguousBufferTLVReader & tlvReader, Sigma1Param & output)
CHIP_ERROR CASESession::ParseSigma1(TLV::ContiguousBufferTLVReader & tlvReader, ParseSigma1Param & output)
{
using namespace TLV;

Expand Down
32 changes: 25 additions & 7 deletions src/protocols/secure_channel/CASESession.h
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,10 @@

namespace chip {

namespace Testing {
class FuzzCASESession;
}

// TODO: temporary derive from Messaging::UnsolicitedMessageHandler, actually the CASEServer should be the umh, it will be fixed
// when implementing concurrent CASE session.
class DLL_EXPORT CASESession : public Messaging::UnsolicitedMessageHandler,
Expand Down Expand Up @@ -118,19 +122,35 @@ class DLL_EXPORT CASESession : public Messaging::UnsolicitedMessageHandler,
*/
void SetGroupDataProvider(Credentials::GroupDataProvider * groupDataProvider) { mGroupDataProvider = groupDataProvider; }

// This struct is only serves as a base struct for EncodeSigma1 and ParseSigma1
struct Sigma1Param
{
ByteSpan initiatorRandom;
uint16_t initiatorSessionId;
ByteSpan destinationId;
ByteSpan initiatorEphPubKey;
bool sessionResumptionRequested = false;
bool InitiatorMRPParamsPresent = false;
ByteSpan resumptionId;
ByteSpan initiatorResumeMICSpan;
};

struct EncodeSigma1Param : Sigma1Param
{
const Crypto::P256PublicKey * pEphPubKey;
const ReliableMessageProtocolConfig * initiatorMrpConfig;
uint8_t initiatorResume1MIC[Crypto::CHIP_CRYPTO_AEAD_MIC_LENGTH_BYTES];
};

struct ParseSigma1Param : Sigma1Param
{
ByteSpan initiatorEphPubKey;
bool InitiatorMRPParamsPresent = false;
};

/*
* TLV Encodes a Sigma1 message into the payload handled by msg
*/
CHIP_ERROR EncodeSigma1(System::PacketBufferHandle & msg, EncodeSigma1Param & InputEncodeSigma1);

/**
* Parse a sigma1 message. This function will return success only if the
* message passes schema checks. Specifically:
Expand All @@ -149,11 +169,8 @@ class DLL_EXPORT CASESession : public Messaging::UnsolicitedMessageHandler,
* and the resumptionID and initiatorResumeMIC outparams will be set to
* valid values, or the resumptionRequested outparam will be set to false.
*/
CHIP_ERROR ParseSigma1(TLV::ContiguousBufferTLVReader & tlvReader, Sigma1Param & OutputParseSigma1);

// TODO: Add message
// TODO: should i keep it as public? why is ParseSigma1 public?
CHIP_ERROR EncodeSigma1(System::PacketBufferHandle & msg, Sigma1Param & encodeSigma1);
CHIP_ERROR
ParseSigma1(TLV::ContiguousBufferTLVReader & tlvReader, ParseSigma1Param & OutputParseSigma1);

/**
* @brief
Expand Down Expand Up @@ -229,6 +246,7 @@ class DLL_EXPORT CASESession : public Messaging::UnsolicitedMessageHandler,

private:
friend class TestCASESession;
friend class Testing::FuzzCASESession;

using AutoReleaseSessionKey = Crypto::AutoReleaseSymmetricKey<Crypto::Aes128KeyHandle>;

Expand Down
2 changes: 1 addition & 1 deletion src/protocols/secure_channel/tests/TestCASESession.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -745,7 +745,7 @@ static CHIP_ERROR EncodeSigma1(MutableByteSpan & buf)
\
TLV::ContiguousBufferTLVReader reader; \
reader.Init(buf); \
CASESession::Sigma1Param parsedSigma1; \
CASESession::ParseSigma1Param parsedSigma1; \
CASESession session; \
\
EXPECT_EQ(session.ParseSigma1(reader, parsedSigma1) == CHIP_NO_ERROR, params::expectSuccess); \
Expand Down

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