Merge pull request #18 from google/tls_config_lib_impl

Static TLS Configuration Store Library Implementation

internal/v2/tls_config_store/BUILD

@@ -0,0 +1,31 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+package(
+  default_visibility = ["//internal/v2:__subpackages__"],
+)
+
+# TODO(rmehta19) : Investigate how to use embedsrcs with data in a top level directory. If possible, move example_cert_key under s2a-go/internal/v2
+
+go_library(
+  name = "tls_config_store",
+  srcs = ["tls_config_store.go"],
+  importpath = "github.com/google/s2a-go/internal/v2/tls_config_store",
+  embedsrcs = [
+    "example_cert_key/client_cert.pem",
+    "example_cert_key/client_key.pem",
+    "example_cert_key/server_cert.pem",
+    "example_cert_key/server_key.pem",
+  ],
+)
+
+go_test(
+  name = "tls_config_store_test",
+  srcs = ["tls_config_store_test.go"],
+  embed = [":tls_config_store"],
+  embedsrcs = [
+    "example_cert_key/client_cert.pem",
+    "example_cert_key/client_key.pem",
+    "example_cert_key/server_cert.pem",
+    "example_cert_key/server_key.pem",
+  ],
+)

internal/v2/tls_config_store/example_cert_key/client_cert.pem

@@ -0,0 +1,25 @@
+-----BEGIN CERTIFICATE-----
+MIID8TCCAtmgAwIBAgIUMAQ1JyjU7PmSuf4+y86CHTI4XHcwDQYJKoZIhvcNAQEL
+BQAwgYcxCzAJBgNVBAYTAlVTMQswCQYDVQQIDAJDQTESMBAGA1UEBwwJU3Vubnl2
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+TByGbU2PavPBvbLTi4zVm8dLoU+1ObLv8PzsbJhA27tIlkOs82im2ul+XLTkHvbB
+uIpxoWA=
+-----END CERTIFICATE-----
+

internal/v2/tls_config_store/example_cert_key/client_key.pem

@@ -0,0 +1,28 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIEpAIBAAKCAQEA73LaT+MFIDhjOS53/rqfFAw+SQ9Jj9ay1U1qmIxitsrkFP1S
+4+PcbEId5brOxhXelrdwrIKSiFQVIHeX879wQzHOLRbC05lIShDq2GQt4MbXdRQ/
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+JwHaZY3MBJ9Zt+nBTWntUgdeNRz5XP8hUy65D7W8k1FaNsBGX9MdocYpyleVGkZ1
+DaMRMgUu4p47jPSYjNqsqh37FmdRscqRe2F5eLlxCyJh3z5k5ND1YA==
+-----END RSA PRIVATE KEY-----
+

internal/v2/tls_config_store/example_cert_key/server_cert.pem

@@ -0,0 +1,25 @@
+-----BEGIN CERTIFICATE-----
+MIID8TCCAtmgAwIBAgIUISXQBSlrMDJp9mRdibxw/RV9X6wwDQYJKoZIhvcNAQEL
+BQAwgYcxCzAJBgNVBAYTAlVTMQswCQYDVQQIDAJDQTESMBAGA1UEBwwJU3Vubnl2
+YWxlMRAwDgYDVQQKDAdDb21wYW55MREwDwYDVQQLDAhEaXZpc2lvbjEWMBQGA1UE
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+AhxtER4=
+-----END CERTIFICATE-----
+

internal/v2/tls_config_store/example_cert_key/server_key.pem

@@ -0,0 +1,28 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIEpQIBAAKCAQEAvbcv/O8JB3oeUY1dwSfQgbotNM/a6euK07ri8F1XcHmsI19k
+RnmSSS4m0JOYk1Q6K8+REniJgAJKVyN6kr58RR0buKGFjG6uuTDe0sJHHdiN7GXK
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+XYTuBDwwVBV+1x7xZQ3vpoohrYcLD9Yd3lUE3LQJcu4zYvaQ/E5H+3I=
+-----END RSA PRIVATE KEY-----
+

internal/v2/tls_config_store/tls_config_store.go

@@ -0,0 +1,99 @@
+// Builds TLS configurations that offload operations to S2Av2.
+package tlsconfigstore
+
+import (
+	"log"
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"time"
+
+	_ "embed"
+)
+
+var (
+	//go:embed example_cert_key/client_cert.pem
+	clientCert []byte
+	//go:embed example_cert_key/server_cert.pem
+	serverCert []byte
+	//go:embed example_cert_key/client_key.pem
+	clientKey []byte
+	//go:embed example_cert_key/server_key.pem
+	serverKey []byte
+)
+
+// GetTlsConfigurationForClient returns a tls.Config instance for use by a client application.
+func GetTlsConfigurationForClient() *tls.Config {
+	// TODO(rmehta19): Call remote signer library for private key.
+	cert, err := tls.X509KeyPair(clientCert, clientKey)
+	if err != nil {
+		log.Fatalf("Failed to generate X509KeyPair: %v", err)
+	}
+
+	rootCertPool := x509.NewCertPool()
+	rootCertPool.AppendCertsFromPEM(serverCert)
+
+	// TODO(rmehta19): Call S2Av2 for config values.
+	// Create mTLS credentials for client.
+	return &tls.Config {
+		Certificates: []tls.Certificate{cert},
+		VerifyPeerCertificate: verifyPeerCertificateFunc("s2a_test_cert", rootCertPool), // TODO(rmehta19): Call cert verifier library.
+		RootCAs: rootCertPool,
+		InsecureSkipVerify: true,
+		ClientSessionCache: nil,
+		MinVersion: uint16(tls.VersionTLS13),
+		MaxVersion: uint16(tls.VersionTLS13),
+	}
+}
+
+// GetTlsConfigurationForServer returns a tls.Config instance for use by a server application.
+func GetTlsConfigurationForServer() *tls.Config {
+	// TODO(rmehta19): Call remote signer library for Private Key.
+	cert, err := tls.X509KeyPair(serverCert, serverKey)
+	if err != nil {
+		log.Fatalf("Failed to generate X509KeyPair: %v", err)
+	}
+
+	certPool := x509.NewCertPool()
+	certPool.AppendCertsFromPEM(clientCert)
+
+
+	// TODO(rmehta19): Call S2Av2 for config values.
+	// Create mTLS credentials for server.
+	return &tls.Config {
+		Certificates: []tls.Certificate{cert},
+		VerifyPeerCertificate: verifyPeerCertificateFunc("s2a_test_cert", certPool), // TODO(rmehta19): Call cert verifier library.
+		ClientAuth: tls.RequireAndVerifyClientCert,
+		ClientCAs: certPool,
+		InsecureSkipVerify: true,
+		MinVersion: uint16(tls.VersionTLS13),
+		MaxVersion: uint16(tls.VersionTLS13),
+	}
+}
+
+// TODO(rmehta19): Remove this static implementation once Certificate Verifier library(contains APIs for VerifyClientCertificateChain and VerifyServerCertificateChain) implementation completed.
+func verifyPeerCertificateFunc(instanceName string, pool *x509.CertPool) func(rawCerts [][]byte, verifiedChains [][]*x509.Certificate) error {
+	return func(rawCerts [][]byte, verifiedChains [][]*x509.Certificate) error {
+		if len(rawCerts) == 0 {
+			return fmt.Errorf("no certificate to verify")
+		}
+		cert, err := x509.ParseCertificate(rawCerts[0])
+		if err != nil {
+			return fmt.Errorf("ParseCertificate failed: %v", err)
+		}
+
+		opts := x509.VerifyOptions{
+			CurrentTime: time.Now(),
+			Roots:       pool,
+		}
+
+		if _, err = cert.Verify(opts); err != nil {
+			return err
+		}
+
+		if cert.Subject.CommonName != instanceName {
+			return fmt.Errorf("certificate had Common Name %q, expected %q", cert.Subject.CommonName, instanceName)
+		}
+		return nil
+	}
+}

internal/v2/tls_config_store/tls_config_store_test.go

@@ -0,0 +1,115 @@
+package tlsconfigstore
+
+import (
+	"testing"
+	"crypto/tls"
+	"bytes"
+
+	_ "embed"
+)
+
+var (
+	//go:embed example_cert_key/client_cert.pem
+	clientCertpem []byte
+	//go:embed example_cert_key/server_cert.pem
+	serverCertpem []byte
+	//go:embed example_cert_key/client_key.pem
+	clientKeypem []byte
+	//go:embed example_cert_key/server_key.pem
+	serverKeypem []byte
+)
+
+
+// TODO(rmehta19): In Client and Server test, verify contents of config.RootCAs once x509.CertPool.Equal function is officially released : https://cs.opensource.google/go/go/+/4aacb7ff0f103d95a724a91736823f44aa599634 .
+
+// TestTLSConfigStoreClient runs unit tests for GetTlsConfigurationForClient.
+func TestTLSConfigStoreClient(t *testing.T) {
+	// Setup for static client test.
+	cert, err := tls.X509KeyPair(clientCertpem, clientKeypem)
+	if err != nil {
+		t.Errorf("Test suite setup failed")
+	}
+
+	for _, tc := range []struct {
+		description		    string
+		Certificates                []tls.Certificate
+		InsecureSkipVerify          bool
+		ClientSessionCache	    tls.ClientSessionCache
+		MinVersion	            uint16
+		MaxVersion		    uint16
+	}{
+		{
+			description: "static",
+			Certificates: []tls.Certificate{cert},
+			InsecureSkipVerify: true,
+			ClientSessionCache: nil,
+			MinVersion: tls.VersionTLS13,
+			MaxVersion: tls.VersionTLS13,
+		},
+	} {
+		t.Run(tc.description, func(t *testing.T) {
+			config := GetTlsConfigurationForClient()
+			if got, want := config.Certificates[0].Certificate[0], tc.Certificates[0].Certificate[0]; !bytes.Equal(got, want) {
+				t.Errorf("config.Certificates[0].Certificate[0] = %v, want %v", got, want)
+			}
+			if got, want := config.InsecureSkipVerify, tc.InsecureSkipVerify; got != want {
+				t.Errorf("config.InsecureSkipVerify = %v, want %v", got, want)
+			}
+			if got, want := config.ClientSessionCache, tc.ClientSessionCache; got != want {
+				t.Errorf("config.ClientSessionCache = %v, want %v", got, want)
+			}
+			if got, want := config.MinVersion, tc.MinVersion; got != want {
+				t.Errorf("config.MinVersion = %v, want %v", got, want)
+			}
+			if got, want := config.MaxVersion, tc.MaxVersion; got != want {
+				t.Errorf("config.MaxVersion = %v, want %v", got, want)
+			}
+		})
+	}
+}
+
+// TestTLSConfigStoreServer runs unit tests for GetTLSConfigurationForServer.
+func TestTLSConfigStoreServer(t *testing.T) {
+	// Setup for static server test.
+	cert, err := tls.X509KeyPair(serverCertpem, serverKeypem)
+	if err != nil {
+		t.Errorf("Test suite setup failed")
+	}
+
+	for _, tc := range []struct {
+		description		    string
+		Certificates                []tls.Certificate
+		ClientAuth		    tls.ClientAuthType
+		InsecureSkipVerify          bool
+		MinVersion	            uint16
+		MaxVersion		    uint16
+	}{
+		{
+			description: "static",
+			Certificates: []tls.Certificate{cert},
+			ClientAuth: tls.RequireAndVerifyClientCert,
+			InsecureSkipVerify: true,
+			MinVersion: tls.VersionTLS13,
+			MaxVersion: tls.VersionTLS13,
+		},
+	} {
+		t.Run(tc.description, func(t *testing.T) {
+			config := GetTlsConfigurationForServer()
+			if got, want := config.Certificates[0].Certificate[0], tc.Certificates[0].Certificate[0]; !bytes.Equal(got,want) {
+				t.Errorf("config.Certificates[0].Certificate[0] = %v, want %v", got, want)
+			}
+			if got, want := config.ClientAuth, tc.ClientAuth; got != want {
+				t.Errorf("config.ClientAuth = %v, want %v", got, want)
+			}
+			if got, want := config.InsecureSkipVerify, tc.InsecureSkipVerify; got != want {
+				t.Errorf("config.InsecureSkipVerify = %v, want %v", got, want)
+			}
+			if got, want := config.MinVersion, tc.MinVersion; got != want {
+				t.Errorf("config.MinVersion = %v, want %v", got, want)
+			}
+			if got, want := config.MaxVersion, tc.MaxVersion; got != want {
+				t.Errorf("config.MaxVersion = %v, want %v", got, want)
+			}
+		})
+	}
+}