Add transparent proxy inspection engine with envoy sidecar support

client/inspect/mitm_test.go

@@ -0,0 +1,133 @@
+package inspect
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/tls"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"math/big"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func generateTestCA(t *testing.T) (*x509.Certificate, *ecdsa.PrivateKey) {
+	t.Helper()
+
+	key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err)
+
+	template := &x509.Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			CommonName: "Test CA",
+		},
+		NotBefore:             time.Now().Add(-time.Hour),
+		NotAfter:              time.Now().Add(24 * time.Hour),
+		KeyUsage:              x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
+		BasicConstraintsValid: true,
+		IsCA:                  true,
+	}
+
+	certDER, err := x509.CreateCertificate(rand.Reader, template, template, &key.PublicKey, key)
+	require.NoError(t, err)
+
+	cert, err := x509.ParseCertificate(certDER)
+	require.NoError(t, err)
+
+	return cert, key
+}
+
+func TestCertProvider_GetCertificate(t *testing.T) {
+	ca, caKey := generateTestCA(t)
+	provider := NewCertProvider(ca, caKey)
+
+	cert, err := provider.GetCertificate("example.com")
+	require.NoError(t, err)
+	require.NotNil(t, cert)
+
+	// Verify the leaf certificate
+	assert.Equal(t, "example.com", cert.Leaf.Subject.CommonName)
+	assert.Contains(t, cert.Leaf.DNSNames, "example.com")
+
+	// Verify chain: leaf + CA
+	assert.Len(t, cert.Certificate, 2)
+
+	// Verify leaf is signed by our CA
+	pool := x509.NewCertPool()
+	pool.AddCert(ca)
+	_, err = cert.Leaf.Verify(x509.VerifyOptions{
+		Roots: pool,
+	})
+	require.NoError(t, err)
+}
+
+func TestCertProvider_CachesResults(t *testing.T) {
+	ca, caKey := generateTestCA(t)
+	provider := NewCertProvider(ca, caKey)
+
+	cert1, err := provider.GetCertificate("cached.example.com")
+	require.NoError(t, err)
+
+	cert2, err := provider.GetCertificate("cached.example.com")
+	require.NoError(t, err)
+
+	// Same pointer = cached
+	assert.Equal(t, cert1, cert2)
+}
+
+func TestCertProvider_DifferentHostsDifferentCerts(t *testing.T) {
+	ca, caKey := generateTestCA(t)
+	provider := NewCertProvider(ca, caKey)
+
+	cert1, err := provider.GetCertificate("a.example.com")
+	require.NoError(t, err)
+
+	cert2, err := provider.GetCertificate("b.example.com")
+	require.NoError(t, err)
+
+	assert.NotEqual(t, cert1.Leaf.SerialNumber, cert2.Leaf.SerialNumber)
+}
+
+func TestCertProvider_TLSConfigHandshake(t *testing.T) {
+	ca, caKey := generateTestCA(t)
+	provider := NewCertProvider(ca, caKey)
+
+	tlsConfig := provider.GetTLSConfig()
+	require.NotNil(t, tlsConfig)
+	require.NotNil(t, tlsConfig.GetCertificate)
+
+	// Simulate a ClientHelloInfo
+	hello := &tls.ClientHelloInfo{
+		ServerName: "handshake.example.com",
+	}
+
+	cert, err := tlsConfig.GetCertificate(hello)
+	require.NoError(t, err)
+	assert.Equal(t, "handshake.example.com", cert.Leaf.Subject.CommonName)
+}
+
+func TestCertCache_Eviction(t *testing.T) {
+	cache := newCertCache(3)
+
+	for i := range 5 {
+		hostname := string(rune('a'+i)) + ".example.com"
+		cache.put(hostname, &tls.Certificate{})
+	}
+
+	// Only 3 should remain (c, d, e - the most recent)
+	assert.Len(t, cache.entries, 3)
+
+	_, ok := cache.get("a.example.com")
+	assert.False(t, ok, "oldest entry should be evicted")
+
+	_, ok = cache.get("b.example.com")
+	assert.False(t, ok, "second oldest should be evicted")
+
+	_, ok = cache.get("e.example.com")
+	assert.True(t, ok, "newest entry should exist")
+}