[tcat] implementation of TCAT general class commands.

Commit introduces implementation of missing general class commands:
- PresentPskdHash
- PresentPskcHash
- PresentInstallCodeHash
- RequestRandomNumChallenge
- RequestPskdHash

Also include minor fixes in Tcat python client and refactoring of expect
tests for tcat.

src/cli/cli_tcat.cpp

@@ -92,8 +92,9 @@ namespace Cli {
 otTcatAdvertisedDeviceId sAdvertisedDeviceIds[OT_TCAT_DEVICE_ID_MAX];
 otTcatGeneralDeviceId    sGeneralDeviceId;
 
-const char kPskdVendor[] = "JJJJJJ";
-const char kUrl[]        = "dummy_url";
+const char kPskdVendor[]    = "JJJJJJ";
+const char kInstallVendor[] = "InstallCode";
+const char kUrl[]           = "dummy_url";
 
 static bool IsDeviceIdSet(void)
 {
@@ -250,6 +251,7 @@ template <> otError Tcat::Process<Cmd("start")>(Arg aArgs[])
     ClearAllBytes(mVendorInfo);
     mVendorInfo.mPskdString      = kPskdVendor;
     mVendorInfo.mProvisioningUrl = kUrl;
+    mVendorInfo.mInstallCode     = kInstallVendor;
 
     if (IsDeviceIdSet())
     {

src/core/meshcop/secure_transport.cpp

@@ -425,7 +425,6 @@ Error SecureTransport::Setup(bool aClient)
 int SecureTransport::SetApplicationSecureKeys(void)
 {
     int rval = 0;
-
     switch (mCipherSuites[0])
     {
     case MBEDTLS_TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8:

src/core/meshcop/secure_transport.hpp

@@ -321,6 +321,16 @@ class SecureTransport : public InstanceLocator
      *
      */
     void SetCaCertificateChain(const uint8_t *aX509CaCertificateChain, uint32_t aX509CaCertChainLength);
+
+    /**
+     * Extracts public key from it's own certificate.
+     *
+     * @return public key from own certificate in form of entire ASN.1 field.
+     *
+     */
+
+    mbedtls_asn1_buf *GetOwnPublicKey(void) { return &mOwnCert.pk_raw; }
+
 #endif // MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
 
 #if defined(MBEDTLS_BASE64_C) && defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)

src/core/meshcop/tcat_agent.cpp

@@ -32,8 +32,12 @@
  */
 
 #include "tcat_agent.hpp"
+#include <cstddef>
 #include <openthread/tcat.h>
+#include <openthread/platform/toolchain.h>
+#include "common/error.hpp"
 #include "meshcop/network_name.hpp"
+#include "thread/key_manager.hpp"
 
 #if OPENTHREAD_CONFIG_BLE_TCAT_ENABLE
 
@@ -42,6 +46,7 @@
 #include "common/debug.hpp"
 #include "common/encoding.hpp"
 #include "common/locator_getters.hpp"
+#include "common/random.hpp"
 #include "common/string.hpp"
 #include "instance/instance.hpp"
 #include "radio/radio.hpp"
@@ -71,6 +76,7 @@ TcatAgent::TcatAgent(Instance &aInstance)
     , mCommissionerHasNetworkName(false)
     , mCommissionerHasDomainName(false)
     , mCommissionerHasExtendedPanId(false)
+    , mRandomChallenge(0)
 {
     mJoinerPskd.Clear();
     mCurrentServiceName[0] = 0;
@@ -84,6 +90,7 @@ Error TcatAgent::Start(AppDataReceiveCallback aAppDataReceiveCallback, JoinCallb
     VerifyOrExit(mVendorInfo != nullptr, error = kErrorFailed);
     mAppDataReceiveCallback.Set(aAppDataReceiveCallback, aContext);
     mJoinCallback.Set(aHandler, aContext);
+    mRandomChallenge = 0;
 
     mCurrentApplicationProtocol = kApplicationProtocolNone;
     mState                      = kStateEnabled;
@@ -99,6 +106,7 @@ void TcatAgent::Stop(void)
     mState                      = kStateDisabled;
     mAppDataReceiveCallback.Clear();
     mJoinCallback.Clear();
+    mRandomChallenge = 0;
     LogInfo("TCAT agent stopped");
 }
 
@@ -180,6 +188,7 @@ void TcatAgent::Disconnected(void)
     {
         mState = kStateEnabled;
     }
+    mRandomChallenge = 0;
 
     LogInfo("TCAT agent disconnected");
 }
@@ -436,7 +445,21 @@ Error TcatAgent::HandleSingleTlv(const Message &aIncomingMessage, Message &aOutg
         case kTlvGetProvisioningURL:
             error = HandleGetProvisioningUrl(aOutgoingMessage, response);
             break;
-
+        case kTlvPresentPskdHash:
+            error = HandlePresentPskdHash(aIncomingMessage, offset, length);
+            break;
+        case kTlvPresentPskcHash:
+            error = HandlePresentPskcHash(aIncomingMessage, offset, length);
+            break;
+        case kTlvPresentInstallCodeHash:
+            error = HandlePresentInstallCodeHash(aIncomingMessage, offset, length);
+            break;
+        case kTlvRequestRandomNumChallenge:
+            error = HandleRequestRandomNumberChallenge(aOutgoingMessage, response);
+            break;
+        case kTlvRequestPskdHash:
+            error = HandleRequestPskdHash(aIncomingMessage, aOutgoingMessage, offset, length, response);
+            break;
         default:
             error = kErrorInvalidCommand;
         }
@@ -471,6 +494,10 @@ Error TcatAgent::HandleSingleTlv(const Message &aIncomingMessage, Message &aOutg
             statusCode = kStatusUnsupported;
             break;
 
+        case kErrorSecurity:
+            statusCode = kStatusHashError;
+            break;
+
         default:
             statusCode = kStatusGeneralError;
             break;
@@ -629,13 +656,135 @@ Error TcatAgent::HandleGetProvisioningUrl(Message &aOutgoingMessage, bool &respo
     length = StringLength(mVendorInfo->mProvisioningUrl, kProvisioningUrlMaxLength);
     VerifyOrExit(length > 0 && length <= Tlv::kBaseTlvMaxLength, error = kErrorInvalidState);
 
-    error    = Tlv::AppendTlv(aOutgoingMessage, kTlvResponseWithPayload, mVendorInfo->mProvisioningUrl, length);
+    SuccessOrExit(error =
+                      Tlv::AppendTlv(aOutgoingMessage, kTlvResponseWithPayload, mVendorInfo->mProvisioningUrl, length));
+    response = true;
+
+exit:
+    return error;
+}
+
+Error TcatAgent::HandlePresentPskdHash(const Message &aIncomingMessage, uint16_t aOffset, uint16_t aLength)
+{
+    Error error = kErrorNone;
+
+    VerifyOrExit(mVendorInfo->mPskdString != nullptr, error = kErrorSecurity);
+
+    error = VerifyHash(aIncomingMessage, aOffset, aLength, mVendorInfo->mPskdString,
+                       StringLength(mVendorInfo->mPskdString, kMaxPSKdLength));
+
+exit:
+    return error;
+}
+
+Error TcatAgent::HandlePresentPskcHash(const Message &aIncomingMessage, uint16_t aOffset, uint16_t aLength)
+{
+    Error         error = kErrorNone;
+    Dataset::Info datasetInfo;
+    Pskc          pskc;
+
+    VerifyOrExit(Get<ActiveDatasetManager>().Read(datasetInfo) == kErrorNone, error = kErrorSecurity);
+    VerifyOrExit(datasetInfo.IsPresent<Dataset::kPskc>(), error = kErrorSecurity);
+    pskc = datasetInfo.Get<Dataset::kPskc>();
+
+    error = VerifyHash(aIncomingMessage, aOffset, aLength, reinterpret_cast<const char *>(pskc.m8), Pskc::kSize);
+
+exit:
+    return error;
+}
+
+Error TcatAgent::HandlePresentInstallCodeHash(const Message &aIncomingMessage, uint16_t aOffset, uint16_t aLength)
+{
+    Error error = kErrorNone;
+
+    VerifyOrExit(mVendorInfo->mInstallCode != nullptr, error = kErrorSecurity);
+
+    error = VerifyHash(aIncomingMessage, aOffset, aLength, mVendorInfo->mInstallCode,
+                       StringLength(mVendorInfo->mInstallCode, 255));
+
+exit:
+    return error;
+}
+
+Error TcatAgent::HandleRequestRandomNumberChallenge(Message &aOutgoingMessage, bool &response)
+{
+    Error error = kErrorNone;
+
+    SuccessOrExit(error = Random::Crypto::Fill(mRandomChallenge));
+
+    SuccessOrExit(
+        error = Tlv::AppendTlv(aOutgoingMessage, kTlvResponseWithPayload, &mRandomChallenge, sizeof(mRandomChallenge)));
+    response = true;
+exit:
+    return error;
+}
+
+Error TcatAgent::HandleRequestPskdHash(const Message &aIncomingMessage,
+                                       Message       &aOutgoingMessage,
+                                       uint16_t       aOffset,
+                                       uint16_t       aLength,
+                                       bool          &response)
+{
+    Error                    error             = kErrorNone;
+    uint64_t                 providedChallenge = 0;
+    Crypto::HmacSha256::Hash hash;
+
+    VerifyOrExit(StringLength(mVendorInfo->mPskdString, kMaxPSKdLength) != 0, error = kErrorFailed);
+    VerifyOrExit(aLength == sizeof(providedChallenge), error = kErrorParse);
+
+    SuccessOrExit(error = aIncomingMessage.Read(aOffset, &providedChallenge, aLength));
+
+    hash = CalculateHash(providedChallenge, mVendorInfo->mPskdString,
+                         StringLength(mVendorInfo->mPskdString, kMaxPSKdLength));
+
+    SuccessOrExit(error = Tlv::AppendTlv(aOutgoingMessage, kTlvResponseWithPayload, hash.GetBytes(),
+                                         Crypto::HmacSha256::Hash::kSize));
     response = true;
 
 exit:
     return error;
 }
 
+Error TcatAgent::VerifyHash(const Message &aIncomingMessage,
+                            uint16_t       aOffset,
+                            uint16_t       aLength,
+                            const char    *aBuf,
+                            size_t         aBufLen)
+{
+    Error                    error = kErrorNone;
+    Crypto::HmacSha256::Hash hash;
+    Crypto::HmacSha256::Hash recivedHash;
+
+    VerifyOrExit(aLength == Crypto::HmacSha256::Hash::kSize, error = kErrorSecurity);
+    VerifyOrExit(mRandomChallenge != 0, error = kErrorSecurity);
+
+    SuccessOrExit(error = aIncomingMessage.Read(aOffset, recivedHash.m8, aLength));
+
+    hash = CalculateHash(mRandomChallenge, aBuf, aBufLen);
+
+    VerifyOrExit(hash == recivedHash, error = kErrorSecurity);
+
+exit:
+    return error;
+}
+
+Crypto::HmacSha256::Hash TcatAgent::CalculateHash(uint64_t aChallenge, const char *aBuf, size_t aBufLen)
+{
+    mbedtls_asn1_buf        *rawKey = Get<Ble::BleSecure>().GetOwnPublicKey();
+    Crypto::Key              cryptoKey;
+    Crypto::HmacSha256       hmac;
+    Crypto::HmacSha256::Hash hash;
+
+    cryptoKey.Set(rawKey->p, rawKey->len);
+
+    hmac.Start(cryptoKey);
+    hmac.Update(aChallenge);
+    hmac.Update(aBuf, aBufLen);
+    hmac.Finish(hash);
+
+    return hash;
+}
+
 Error TcatAgent::HandleStartThreadInterface(void)
 {
     Error         error;

src/core/meshcop/tcat_agent.hpp

@@ -363,8 +363,24 @@ class TcatAgent : public InstanceLocator, private NonCopyable
     Error HandleGetDeviceId(Message &aOutgoingMessage, bool &response);
     Error HandleGetExtPanId(Message &aOutgoingMessage, bool &response);
     Error HandleGetProvisioningUrl(Message &aOutgoingMessage, bool &response);
+    Error HandlePresentPskdHash(const Message &aIncomingMessage, uint16_t aOffset, uint16_t aLength);
+    Error HandlePresentPskcHash(const Message &aIncomingMessage, uint16_t aOffset, uint16_t aLength);
+    Error HandlePresentInstallCodeHash(const Message &aIncomingMessage, uint16_t aOffset, uint16_t aLength);
+    Error HandleRequestRandomNumberChallenge(Message &aOutgoingMessage, bool &response);
+    Error HandleRequestPskdHash(const Message &aIncomingMessage,
+                                Message       &aOutgoingMessage,
+                                uint16_t       aOffset,
+                                uint16_t       aLength,
+                                bool          &response);
     Error HandleStartThreadInterface(void);
 
+    Error                    VerifyHash(const Message &aIncomingMessage,
+                                        uint16_t       aOffset,
+                                        uint16_t       aLength,
+                                        const char    *aBuf,
+                                        size_t         aBufLen);
+    Crypto::HmacSha256::Hash CalculateHash(uint64_t aChallenge, const char *aBuf, size_t aBufLen);
+
     bool         CheckCommandClassAuthorizationFlags(CommandClassFlags aCommissionerCommandClassFlags,
                                                      CommandClassFlags aDeviceCommandClassFlags,
                                                      Dataset          *aDataset) const;
@@ -374,6 +390,7 @@ class TcatAgent : public InstanceLocator, private NonCopyable
     static constexpr uint16_t kJoinerUdpPort            = OPENTHREAD_CONFIG_JOINER_UDP_PORT;
     static constexpr uint16_t kPingPayloadMaxLength     = 512;
     static constexpr uint16_t kProvisioningUrlMaxLength = 64;
+    static constexpr uint16_t kMaxPSKdLength            = OT_JOINER_MAX_PSKD_LENGTH;
     static constexpr uint16_t kTcatMaxDeviceIdSize      = OT_TCAT_MAX_DEVICEID_SIZE;
 
     JoinerPskd                       mJoinerPskd;
@@ -391,6 +408,7 @@ class TcatAgent : public InstanceLocator, private NonCopyable
     bool                             mCommissionerHasNetworkName : 1;
     bool                             mCommissionerHasDomainName : 1;
     bool                             mCommissionerHasExtendedPanId : 1;
+    uint64_t                         mRandomChallenge;
 
     friend class Ble::BleSecure;
 };

src/core/radio/ble_secure.hpp

@@ -357,6 +357,15 @@ class BleSecure : public InstanceLocator, private NonCopyable
         return mTls.GetThreadAttributeFromOwnCertificate(aThreadOidDescriptor, aAttributeBuffer, aAttributeLength);
     }
 
+    /**
+     * Extracts public key from it's own certificate.
+     *
+     * @return public key from own certificate in form of entire ASN.1 field.
+     *
+     */
+
+    mbedtls_asn1_buf *GetOwnPublicKey(void) { return mTls.GetOwnPublicKey(); }
+
     /**
      * Sets the authentication mode for the BLE secure connection. It disables or enables the verification
      * of peer certificate.

tests/scripts/expect/_common.exp

@@ -266,4 +266,35 @@ proc fail {message} {
     error $message
 }
 
+proc spawn_tcat_client_for_node {id} {
+    global tcat_ids
+    global spawn_id
+
+    switch_node $id
+
+    send "tcat start\n"
+    expect_line "Done"
+
+    spawn python "tools/tcat_ble_client/bbtc.py" --simulation $id --cert_path "tools/tcat_ble_client/auth"
+    expect_line "Done"
+
+    set tcat_ids($id) $spawn_id
+
+    return $spawn_id
+}
+
+proc switch_tcat_client_for_node {id} {
+    global tcat_ids
+    global spawn_id
+
+    send_user "\n# ${id}\n"
+    set spawn_id $tcat_ids($id)
+}
+
+proc dispose_tcat_client {id} {
+    switch_tcat_client_for_node $id
+    send "exit\n"
+    expect eof
+}
+
 set timeout 10

tests/scripts/expect/cli-tcat-advertisement.exp

@@ -31,7 +31,6 @@ source "tests/scripts/expect/_common.exp"
 
 spawn_node 1 "cli"
 
-switch_node 1
 send "tcat advid ianapen f378\n"
 expect_line "Done"
 
@@ -89,3 +88,5 @@ expect_line "Done"
 
 send "tcat devid\n"
 expect_line "Done"
+
+dispose_all