tls_utils_test.go

package modbus

import (
	"crypto/x509"
	"io/ioutil"
	"os"
	"testing"
)

// random certs from /etc/ssl/certs
const validCerts = `-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
-----BEGIN CERTIFICATE-----
MIIDnzCCAoegAwIBAgIBJjANBgkqhkiG9w0BAQUFADBxMQswCQYDVQQGEwJERTEc
MBoGA1UEChMTRGV1dHNjaGUgVGVsZWtvbSBBRzEfMB0GA1UECxMWVC1UZWxlU2Vj
IFRydXN0IENlbnRlcjEjMCEGA1UEAxMaRGV1dHNjaGUgVGVsZWtvbSBSb290IENB
IDIwHhcNOTkwNzA5MTIxMTAwWhcNMTkwNzA5MjM1OTAwWjBxMQswCQYDVQQGEwJE
RTEcMBoGA1UEChMTRGV1dHNjaGUgVGVsZWtvbSBBRzEfMB0GA1UECxMWVC1UZWxl
U2VjIFRydXN0IENlbnRlcjEjMCEGA1UEAxMaRGV1dHNjaGUgVGVsZWtvbSBSb290
IENBIDIwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCrC6M14IspFLEU
ha88EOQ5bzVdSq7d6mGNlUn0b2SjGmBmpKlAIoTZ1KXleJMOaAGtuU1cOs7TuKhC
QN/Po7qCWWqSG6wcmtoIKyUn+WkjR/Hg6yx6m/UTAtB+NHzCnjwAWav12gz1Mjwr
rFDa1sPeg5TKqAyZMg4ISFZbavva4VhYAUlfckE8FQYBjl2tqriTtM2e66foai1S
NNs671x1Udrb8zH57nGYMsRUFUQM+ZtV7a3fGAigo4aKSe5TBY8ZTNXeWHmb0moc
QqvF1afPaA+W5OFhmHZhyJF81j4A4pFQh+GdCuatl9Idxjp9y7zaAzTVjlsB9WoH
txa2bkp/AgMBAAGjQjBAMB0GA1UdDgQWBBQxw3kbuvVT1xfgiXotF2wKsyudMzAP
BgNVHRMECDAGAQH/AgEFMA4GA1UdDwEB/wQEAwIBBjANBgkqhkiG9w0BAQUFAAOC
AQEAlGRZrTlk5ynrE/5aw4sTV8gEJPB0d8Bg42f76Ymmg7+Wgnxu1MM9756Abrsp
tJh6sTtU6zkXR34ajgv8HzFZMQSyzhfzLMdiNlXiItiJVbSYSKpk+tYcNthEeFpa
IzpXl/V6ME+un2pMSyuOoAPjPuCp1NJ70rOo4nI8rZ7/gFnkm0W09juwzTkZmDLl
6iFhkOQxIY40sfcvNUqFENrnijchvllj4PKFiDFT1FQUhXB59C4Gdyd1Lx+4ivn+
xbrYNuSD7Odlt79jWvNGr4GUN9RBjNYj1h7P9WgbRGOiWrqnNVmh5XAFmw4jV5mU
Cm26OWMohpLzGITY+9HPBVZkVw==
-----END CERTIFICATE-----
`

func TestLoadCertPool(t *testing.T) {
	var err  error
	var cp   *x509.CertPool
	var fd   *os.File
	var path string

	// attemp to load a non-existent file: should fail
	cp, err = LoadCertPool("non/existent/path/to/store")
	if err == nil {
		t.Errorf("LoadCertPool() should have failed")
	}

	// create an empty file and attempt to load it: should fail
	fd, err = ioutil.TempFile("", "modbus_tls_utils_test")
	if err != nil {
		t.Errorf("failed to create temp file: %v", err)
		return
	}
	path = fd.Name()

	defer os.Remove(path)
	err = fd.Close()
	if err != nil {
		t.Errorf("failed to close temp file: %v", err)
		return
	}

	cp, err = LoadCertPool(path)
	if err == nil {
		t.Errorf("LoadCertPool() should have failed")
	}

	// put garbage into a file and attempt to load it: should fail
	fd, err = ioutil.TempFile("", "modbus_tls_utils_test")
	if err != nil {
		t.Errorf("failed to create temp file: %v", err)
	}
	path = fd.Name()

	defer os.Remove(path)
	_, err = fd.Write([]byte("somejunk"))
	if err != nil {
		t.Errorf("failed to write to temp file: %v", err)
	}
	err = fd.Close()
	if err != nil {
		t.Errorf("failed to close temp file: %v", err)
		return
	}

	cp, err = LoadCertPool(path)
	if err == nil {
		t.Errorf("LoadCertPool() should have failed")
	}

	// now write two certs to a file and try to load it: should succeed
	fd, err = ioutil.TempFile("", "modbus_tls_utils_test")
	if err != nil {
		t.Errorf("failed to create temp file: %v", err)
	}
	path = fd.Name()

	defer os.Remove(path)
	_, err = fd.Write([]byte(validCerts))
	if err != nil {
		t.Errorf("failed to write to temp file: %v", err)
	}
	err = fd.Close()
	if err != nil {
		t.Errorf("failed to close temp file: %v", err)
		return
	}

	cp, err = LoadCertPool(path)
	if err != nil {
		t.Errorf("LoadCertPool() should have succeeded, got: %v", err)
	}

	// expect two certs in the cert pool
	if len(cp.Subjects()) != 2 {
		t.Errorf("expected 2 certs in the pool, saw: %v", len(cp.Subjects()))
	}

	return
}