move the STK generation from the ServerConfig to a separate struct

crypto/source_address_token.go

@@ -58,7 +58,11 @@ const stkKeySize = 16
 const stkNonceSize = 16
 
 // NewStkSource creates a source for source address tokens
-func NewStkSource(secret []byte) (StkSource, error) {
+func NewStkSource() (StkSource, error) {
+	secret := make([]byte, 32)
+	if _, err := rand.Read(secret); err != nil {
+		return nil, err
+	}
 	key, err := deriveKey(secret)
 	if err != nil {
 		return nil, err

crypto/source_address_token_test.go

@@ -43,7 +43,6 @@ var _ = Describe("Source Address Tokens", func() {
 	Context("source", func() {
 		var (
 			source *stkSource
-			secret []byte
 			ip4    net.IP
 			ip6    net.IP
 		)
@@ -56,8 +55,7 @@ var _ = Describe("Source Address Tokens", func() {
 			ip6 = net.ParseIP("2001:0db8:0000:0000:0000:ff00:0042:8329")
 			Expect(ip6).NotTo(BeEmpty())
 
-			secret = []byte("TESTING")
-			sourceI, err := NewStkSource(secret)
+			sourceI, err := NewStkSource()
 			source = sourceI.(*stkSource)
 			Expect(err).NotTo(HaveOccurred())
 		})

handshake/crypto_setup_server.go

@@ -27,6 +27,7 @@ type cryptoSetupServer struct {
 	connID               protocol.ConnectionID
 	sourceAddr           []byte
 	scfg                 *ServerConfig
+	stkGenerator         *STKGenerator
 	diversificationNonce []byte
 
 	version           protocol.VersionNumber
@@ -68,6 +69,11 @@ func NewCryptoSetup(
 	supportedVersions []protocol.VersionNumber,
 	aeadChanged chan<- protocol.EncryptionLevel,
 ) (CryptoSetup, error) {
+	stkGenerator, err := NewSTKGenerator()
+	if err != nil {
+		return nil, err
+	}
+
 	var sourceAddr []byte
 	if udpAddr, ok := remoteAddr.(*net.UDPAddr); ok {
 		sourceAddr = udpAddr.IP
@@ -81,6 +87,7 @@ func NewCryptoSetup(
 		version:              version,
 		supportedVersions:    supportedVersions,
 		scfg:                 scfg,
+		stkGenerator:         stkGenerator,
 		keyDerivation:        crypto.DeriveKeysAESGCM,
 		keyExchange:          getEphermalKEX,
 		nullAEAD:             crypto.NewNullAEAD(protocol.PerspectiveServer, version),
@@ -276,7 +283,7 @@ func (h *cryptoSetupServer) isInchoateCHLO(cryptoData map[Tag][]byte, cert []byt
 }
 
 func (h *cryptoSetupServer) verifySTK(stk []byte) bool {
-	stkTime, err := h.scfg.stkSource.VerifyToken(h.sourceAddr, stk)
+	stkTime, err := h.stkGenerator.VerifyToken(h.sourceAddr, stk)
 	if err != nil {
 		utils.Debugf("STK invalid: %s", err.Error())
 		return false
@@ -292,7 +299,7 @@ func (h *cryptoSetupServer) handleInchoateCHLO(sni string, chlo []byte, cryptoDa
 		return nil, qerr.Error(qerr.CryptoInvalidValueLength, "CHLO too small")
 	}
 
-	token, err := h.scfg.stkSource.NewToken(h.sourceAddr)
+	token, err := h.stkGenerator.NewToken(h.sourceAddr)
 	if err != nil {
 		return nil, err
 	}

handshake/crypto_setup_server_test.go

@@ -194,7 +194,6 @@ var _ = Describe("Server Crypto Setup", func() {
 		versionTag = make([]byte, 4)
 		binary.LittleEndian.PutUint32(versionTag, protocol.VersionNumberToTag(protocol.VersionWhatever))
 		Expect(err).NotTo(HaveOccurred())
-		scfg.stkSource = &mockStkSource{}
 		version = protocol.SupportedVersions[len(protocol.SupportedVersions)-1]
 		supportedVersions = []protocol.VersionNumber{version, 98, 99}
 		cpm = NewConnectionParamatersManager(protocol.PerspectiveServer, protocol.VersionWhatever)
@@ -210,6 +209,7 @@ var _ = Describe("Server Crypto Setup", func() {
 		)
 		Expect(err).NotTo(HaveOccurred())
 		cs = csInt.(*cryptoSetupServer)
+		cs.stkGenerator.stkSource = &mockStkSource{}
 		cs.keyDerivation = mockKeyDerivation
 		cs.keyExchange = func() crypto.KeyExchange { return &mockKEX{ephermal: true} }
 	})
@@ -436,12 +436,12 @@ var _ = Describe("Server Crypto Setup", func() {
 
 		It("recognizes inchoate CHLOs with an invalid STK", func() {
 			testErr := errors.New("STK invalid")
-			scfg.stkSource.(*mockStkSource).verifyErr = testErr
+			cs.stkGenerator.stkSource.(*mockStkSource).verifyErr = testErr
 			Expect(cs.isInchoateCHLO(fullCHLO, cert)).To(BeTrue())
 		})
 
 		It("REJ messages that have an expired STK", func() {
-			cs.scfg.stkSource.(*mockStkSource).stkTime = time.Now().Add(-protocol.STKExpiryTime).Add(-time.Second)
+			cs.stkGenerator.stkSource.(*mockStkSource).stkTime = time.Now().Add(-protocol.STKExpiryTime).Add(-time.Second)
 			Expect(cs.isInchoateCHLO(fullCHLO, cert)).To(BeTrue())
 		})
 

handshake/server_config.go

@@ -13,7 +13,6 @@ type ServerConfig struct {
 	certChain crypto.CertChain
 	ID        []byte
 	obit      []byte
-	stkSource crypto.StkSource
 }
 
 // NewServerConfig creates a new server config
@@ -24,27 +23,16 @@ func NewServerConfig(kex crypto.KeyExchange, certChain crypto.CertChain) (*Serve
 		return nil, err
 	}
 
-	stkSecret := make([]byte, 32)
-	if _, err = rand.Read(stkSecret); err != nil {
-		return nil, err
-	}
-
 	obit := make([]byte, 8)
 	if _, err = rand.Read(obit); err != nil {
 		return nil, err
 	}
 
-	stkSource, err := crypto.NewStkSource(stkSecret)
-	if err != nil {
-		return nil, err
-	}
-
 	return &ServerConfig{
 		kex:       kex,
 		certChain: certChain,
 		ID:        id,
 		obit:      obit,
-		stkSource: stkSource,
 	}, nil
 }
 

handshake/stk_generator.go

@@ -0,0 +1,33 @@
+package handshake
+
+import (
+	"time"
+
+	"github.com/lucas-clemente/quic-go/crypto"
+)
+
+// An STKGenerator generates STKs
+type STKGenerator struct {
+	stkSource crypto.StkSource
+}
+
+// NewSTKGenerator initializes a new STKGenerator
+func NewSTKGenerator() (*STKGenerator, error) {
+	stkSource, err := crypto.NewStkSource()
+	if err != nil {
+		return nil, err
+	}
+	return &STKGenerator{
+		stkSource: stkSource,
+	}, nil
+}
+
+// NewToken generates a new STK token for a given source address
+func (g *STKGenerator) NewToken(sourceAddr []byte) ([]byte, error) {
+	return g.stkSource.NewToken(sourceAddr)
+}
+
+// VerifyToken verifies an STK token
+func (g *STKGenerator) VerifyToken(sourceAddr []byte, token []byte) (time.Time, error) {
+	return g.stkSource.VerifyToken(sourceAddr, token)
+}

handshake/stk_generator_test.go

@@ -0,0 +1,35 @@
+package handshake
+
+import (
+	"net"
+	"time"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("STK Generator", func() {
+	var stkGen *STKGenerator
+
+	BeforeEach(func() {
+		var err error
+		stkGen, err = NewSTKGenerator()
+		Expect(err).ToNot(HaveOccurred())
+	})
+
+	It("generates an STK", func() {
+		ip := net.IPv4(127, 0, 0, 1)
+		token, err := stkGen.NewToken(ip)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(token).ToNot(BeEmpty())
+	})
+
+	It("verifies an STK", func() {
+		ip := net.IPv4(192, 168, 0, 1)
+		token, err := stkGen.NewToken(ip)
+		Expect(err).ToNot(HaveOccurred())
+		t, err := stkGen.VerifyToken(ip, token)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(t).To(BeTemporally("~", time.Now(), time.Second))
+	})
+})