Program: 8405
Project: 8405
Buggy source:
public PGPPublicKeyRing signKey(long masterKeyId,long pubKeyId,String passphrase) throws PgpGeneralException, NoSuchAlgorithmException, NoSuchProviderException, PGPException, SignatureException {
  if (passphrase == null) {
    throw new PgpGeneralException("String_Node_Str");
  }
 else {
    PGPPublicKeyRing pubring=ProviderHelper.getPGPPublicKeyRingByKeyId(mContext,pubKeyId);
    PGPSecretKey signingKey=PgpKeyHelper.getCertificationKey(mContext,masterKeyId);
    if (signingKey == null) {
      throw new PgpGeneralException(mContext.getString(R.string.error_signature_failed));
    }
    PBESecretKeyDecryptor keyDecryptor=new JcePBESecretKeyDecryptorBuilder().setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(passphrase.toCharArray());
    PGPPrivateKey signaturePrivateKey=signingKey.extractPrivateKey(keyDecryptor);
    if (signaturePrivateKey == null) {
      throw new PgpGeneralException(mContext.getString(R.string.error_could_not_extract_private_key));
    }
    JcaPGPContentSignerBuilder contentSignerBuilder=new JcaPGPContentSignerBuilder(signingKey.getPublicKey().getAlgorithm(),PGPUtil.SHA256).setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
    PGPSignatureGenerator signatureGenerator=new PGPSignatureGenerator(contentSignerBuilder);
    signatureGenerator.init(PGPSignature.DIRECT_KEY,signaturePrivateKey);
    PGPSignatureSubpacketGenerator spGen=new PGPSignatureSubpacketGenerator();
    PGPSignatureSubpacketVector packetVector=spGen.generate();
    signatureGenerator.setHashedSubpackets(packetVector);
    PGPPublicKey signedKey=PGPPublicKey.addCertification(pubring.getPublicKey(pubKeyId),signatureGenerator.generate());
    pubring=PGPPublicKeyRing.insertPublicKey(pubring,signedKey);
    return pubring;
  }
}

Fixed version (ground truth):
public PGPPublicKeyRing signKey(long masterKeyId,long pubKeyId,String passphrase) throws PgpGeneralException, PGPException, SignatureException {
  if (passphrase == null) {
    throw new PgpGeneralException("String_Node_Str");
  }
 else {
    PGPPublicKeyRing pubring=ProviderHelper.getPGPPublicKeyRingByKeyId(mContext,pubKeyId);
    PGPSecretKey signingKey=PgpKeyHelper.getCertificationKey(mContext,masterKeyId);
    if (signingKey == null) {
      throw new PgpGeneralException(mContext.getString(R.string.error_signature_failed));
    }
    PBESecretKeyDecryptor keyDecryptor=new JcePBESecretKeyDecryptorBuilder().setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(passphrase.toCharArray());
    PGPPrivateKey signaturePrivateKey=signingKey.extractPrivateKey(keyDecryptor);
    if (signaturePrivateKey == null) {
      throw new PgpGeneralException(mContext.getString(R.string.error_could_not_extract_private_key));
    }
    JcaPGPContentSignerBuilder contentSignerBuilder=new JcaPGPContentSignerBuilder(signingKey.getPublicKey().getAlgorithm(),PGPUtil.SHA256).setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
    PGPSignatureGenerator signatureGenerator=new PGPSignatureGenerator(contentSignerBuilder);
    signatureGenerator.init(PGPSignature.DIRECT_KEY,signaturePrivateKey);
    PGPSignatureSubpacketGenerator spGen=new PGPSignatureSubpacketGenerator();
    PGPSignatureSubpacketVector packetVector=spGen.generate();
    signatureGenerator.setHashedSubpackets(packetVector);
    PGPPublicKey signedKey=PGPPublicKey.addCertification(pubring.getPublicKey(pubKeyId),signatureGenerator.generate());
    pubring=PGPPublicKeyRing.insertPublicKey(pubring,signedKey);
    return pubring;
  }
}