[FIXED] Spring Security - X509 Certificate JUnit testing

Issue

I have added X509 Authentication to my backend following this article: https://www.baeldung.com/x-509-authentication-in-spring-security. I've tested in postman and it is working fine I get the Principal extracted from CN.

My problem is that I want to write JUnit tests for this, and check if I can extract correctly the needed principal but I don't know how to start it, how to create X509Certifcate in Java and pass it to my extractor function. I would really appreciate if somebody can explain the needed steps for this, thank you.

Solution

You can create a test certificate for your tests like so:

public static X509Certificate buildTestCertificate() throws Exception {
        String cert = "-----BEGIN CERTIFICATE-----\n"
                + "MIIEQTCCAymgAwIBAgIBATANBgkqhkiG9w0BAQUFADCBkzEaMBgGA1UEAxMRTW9u\n"
                + "a2V5IE1hY2hpbmUgQ0ExCzAJBgNVBAYTAlVLMREwDwYDVQQIEwhTY290bGFuZDEQ\n"
                + "MA4GA1UEBxMHR2xhc2dvdzEcMBoGA1UEChMTbW9ua2V5bWFjaGluZS5jby51azEl\n"
                + "MCMGCSqGSIb3DQEJARYWY2FAbW9ua2V5bWFjaGluZS5jby51azAeFw0wNTAzMDYy\n"
                + "MzI4MjJaFw0wNjAzMDYyMzI4MjJaMIGvMQswCQYDVQQGEwJVSzERMA8GA1UECBMI\n"
                + "U2NvdGxhbmQxEDAOBgNVBAcTB0dsYXNnb3cxGzAZBgNVBAoTEk1vbmtleSBNYWNo\n"
                + "aW5lIEx0ZDElMCMGA1UECxMcT3BlbiBTb3VyY2UgRGV2ZWxvcG1lbnQgTGFiLjEU\n"
                + "MBIGA1UEAxMLTHVrZSBUYXlsb3IxITAfBgkqhkiG9w0BCQEWEmx1a2VAbW9ua2V5\n"
                + "bWFjaGluZTBcMA0GCSqGSIb3DQEBAQUAA0sAMEgCQQDItxZr07mm65ttYH7RMaVo\n"
                + "VeMCq4ptfn+GFFEk4+54OkDuh1CHlk87gEc1jx3ZpQPJRTJx31z3YkiAcP+RDzxr\n"
                + "AgMBAAGjggFIMIIBRDAJBgNVHRMEAjAAMBEGCWCGSAGG+EIBAQQEAwIHgDALBgNV\n"
                + "HQ8EBAMCBeAwHQYDVR0OBBYEFG7mW1czzw4vFcL03+wUvvvPVFY8MIHABgNVHSME\n"
                + "gbgwgbWAFKt47K8QG4qbH8exJY8WKPIXmq02oYGZpIGWMIGTMRowGAYDVQQDExFN\n"
                + "b25rZXkgTWFjaGluZSBDQTELMAkGA1UEBhMCVUsxETAPBgNVBAgTCFNjb3RsYW5k\n"
                + "MRAwDgYDVQQHEwdHbGFzZ293MRwwGgYDVQQKExNtb25rZXltYWNoaW5lLmNvLnVr\n"
                + "MSUwIwYJKoZIhvcNAQkBFhZjYUBtb25rZXltYWNoaW5lLmNvLnVrggEAMDUGCWCG\n"
                + "SAGG+EIBBAQoFiZodHRwczovL21vbmtleW1hY2hpbmUuY28udWsvY2EtY3JsLnBl\n"
                + "bTANBgkqhkiG9w0BAQUFAAOCAQEAZ961bEgm2rOq6QajRLeoljwXDnt0S9BGEWL4\n"
                + "PMU2FXDog9aaPwfmZ5fwKaSebwH4HckTp11xwe/D9uBZJQ74Uf80UL9z2eo0GaSR\n"
                + "nRB3QPZfRvop0I4oPvwViKt3puLsi9XSSJ1w9yswnIf89iONT7ZyssPg48Bojo8q\n"
                + "lcKwXuDRBWciODK/xWhvQbaegGJ1BtXcEHtvNjrUJLwSMDSr+U5oUYdMohG0h1iJ\n"
                + "R+JQc49I33o2cTc77wfEWLtVdXAyYY4GSJR6VfgvV40x85ItaNS3HHfT/aXU1x4m\n"
                + "W9YQkWlA6t0blGlC+ghTOY1JbgWnEfXMmVgg9a9cWaYQ+NQwqA==\n" + "-----END CERTIFICATE-----";
        ByteArrayInputStream in = new ByteArrayInputStream(cert.getBytes());
        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        return (X509Certificate) cf.generateCertificate(in);
}

This piece code was extracted from here.

With the certificate in place, you can pass it to your extractor function and compare the fields.

Answered By - Marcus Hert da Coregio
Answer Checked By - Terry (JavaFixing Volunteer)