CAPLfunctionX509Signer CreateCertificateSignature

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X509Signer_CreateCertificateSignature

CAPL Functions » Security » X509Signer_CreateCertificateSignature

Valid for: CANoe DE • CANoe4SW DE

Method Syntax

dword X509Signer_CreateCertificateSignature(qword objectHandle, qword certificateHandle, byte[] outBuffer, dword outBufferLength)

Description

Creation function for signature for a certificate using the signers private key and the algorithm from signers certificate subject key algorithm. The To Be Signed Certificate will be signed independent from the validity of the certificate content and certificate structure (i.e. invalid certificate structures can receive a valid signature for testing). The certificate will not be updated, only the signature will be returned for manual updates or other use cases. Signer will use the hash function provided at the signer creation or the one associated with the signing algorithm of this signer. Signature algorithm is used from the Public Key Algorithm Identifier of the associated signer certificate.

Parameters

• objectHandle: (in) Handle with type ‘X509Signer’. The function will be called in context of this handle.

Selectors

—

Return Values

• 1: NoError: Operation was completed successfully.
• -2: Nullpointer: Error, the return value of the function was “NULL”. The value is not available and the output buffer is unchanged.
• -3: BufferTooSmall: Error, the output buffer is too small. No value has been written.
• -4: InvalidHandle: Error, the provided objectHandle is invalid or not suitable for this function.
• -5: InvalidArgument: Error, one or more arguments are invalid for this function.
• -6: InvalidArgumentHandle: Error, one or more argument handles are invalid or not suitable for this function.

Example

variables
{
  qword objectFactory;
  // Object handles
  qword pkiAccess, decoder, encoder, verifier, signer, rootCert, ecuCert, subject;
  // Result of certificate chain verification
  dword verificationResult;

  // Buffers
  byte keyBuffer[1000];
  byte byteBuffer[1000];
  char strBuffer[1000];
  dword keyBufferLen;
  dword byteBufferLen;
  dword strBufferLen;
}

void X509_Modify_Sign_And_Verify() {

  // X509 Object factory is the entry point for X.509 features. It is used to create object handles
  objectFactory = GetX509ObjectFactory();
  // Create handles for PkiAccess, Decoder, Encoder, Verifier
  X509ObjectFactory_createX509Decoder(objectFactory, decoder);
  X509ObjectFactory_createX509Encoder(objectFactory, encoder);
  X509ObjectFactory_createX509Verifier(objectFactory, verifier);
  X509ObjectFactory_createX509PkiAccess(objectFactory, pkiAccess);

  // Note: This sample code does not contain the required crypto material.
  // The required format is DER encoded X.509 certificate / private key as hexadecimal string, e.g. 112233AABBDD
  // Please use your existing (hex encoded) key and certificates or use an example value included in Security Manager Configurator

  // Decode the binary root certificate, lead certificate and root private key.
  keyBufferLen = 1000;
  X509ObjectFactory_BytesFromHexString(objectFactory, " *** YOUR HEX ENCODED SIGNER PRIVATE KEY *** ", keyBuffer, keyBufferLen);

  byteBufferLen = 1000;
  X509ObjectFactory_BytesFromHexString(objectFactory, " *** YOUR HEX ENCODED ECU CERTIFICATE *** ", byteBuffer, byteBufferLen);
  X509Decoder_DecodeCertificate(decoder, ecuCert, byteBuffer, byteBufferLen);

  byteBufferLen = 1000;
  X509ObjectFactory_BytesFromHexString(objectFactory, " *** YOUR HEX ENCODED SIGNER CERTIFICATE *** ", byteBuffer, byteBufferLen);
  X509PkiAccess_CreateSigner(pkiAccess, keyBuffer, keyBufferLen, byteBuffer, byteBufferLen, "SHA-256", signer);

  // Load the signer certificate handle
  X509Signer_GetSignerCertificate(signer, rootCert);

  // Now add the root certificates to the truststore of the verifier. These will be used for chain verification
  X509Verifier_AddTrustedCertificate(verifier, rootCert);

  // Verify the certificate against the truststore -> It is unchanged and must be valid
  verificationResult = 0;
  X509Verifier_VerifyCertificateChain(verifier, ecuCert, verificationResult);
  write("Verification result: %d", verificationResult);

  // Update the root certificates validity dates
  X509Certificate_SetValidFrom(rootCert, "20000101000000Z");
  X509Certificate_SetValidTo(rootCert, "20300101000000Z");
  X509Signer_UpdateAndSignCertificate(signer, rootCert);

  // Verify the certificate against the truststore -> Root certificate is re-signed and must be valid
  verificationResult = 0;
  X509Verifier_VerifyCertificateChain(verifier, ecuCert, verificationResult);
  write("Verification result: %d", verificationResult);

  // Get the subject DN from the certificate
  X509Certificate_GetSubjectDN(ecuCert, subject);

  // Update the ecu certificates validity dates
  X509Certificate_SetValidFrom(ecuCert, "20000101000000Z");
  X509Certificate_SetValidTo(ecuCert, "20300101000000Z");
  X509DN_SetValueForAttribute(subject, "2.5.4.3", "TESTTEST"); // Update CN
  X509DN_SetValueForAttribute(subject, "1.2.3.4", "ANOTHER_TESTTEST"); // Add custom Attribute

  // Now update the signature and all relevant fields (Issuer, Auth Key Identifier, SignatureAlgorithm)
  X509Signer_UpdateAndSignCertificate(signer, ecuCert);

  // Again verify the certificate against the truststore -> It received a fresh signature and must be invalid
  verificationResult = 0;
  X509Verifier_VerifyCertificateChain(verifier, ecuCert, verificationResult);
  write("Verification result: %d", verificationResult);

  // Utility to print the byte buffer into a hex string for printing
  write("Generated certificates:");
  write("Root:");
  byteBufferLen = 1000;
  X509Encoder_EncodeCertificate(encoder, rootCert, byteBuffer, byteBufferLen); // (DER-) encode the certificate structure into a byte buffer
  strBufferLen = 1000;
  X509ObjectFactory_BytesToHexString(objectFactory, byteBuffer, byteBufferLen, strBuffer, strBufferLen);
  write("Hex:\n%s", strBuffer);
  strBufferLen = 1000;
  X509Certificate_ToString(rootCert, strBuffer, strBufferLen);
  write("Textual:\n%s", strBuffer);
  write("Child:");
  byteBufferLen = 1000;
  X509Encoder_EncodeCertificate(encoder, ecuCert, byteBuffer, byteBufferLen); // (DER-) encode the certificate structure into a byte buffer
  strBufferLen = 1000;
  X509ObjectFactory_BytesToHexString(objectFactory, byteBuffer, byteBufferLen, strBuffer, strBufferLen);
  write("Hex:\n%s", strBuffer);
  strBufferLen = 1000;
  X509Certificate_ToString(ecuCert, strBuffer, strBufferLen);
  write("Textual:\n%s", strBuffer);
}