Include header when signing v2jwt (#90)

v2/account_claims.go

@@ -168,7 +168,7 @@ func (a *AccountClaims) Encode(pair nkeys.KeyPair) (string, error) {
 	sort.Sort(a.Exports)
 	sort.Sort(a.Imports)
 	a.Type = AccountClaim
-	return a.ClaimsData.Encode(pair, a)
+	return a.ClaimsData.encode(pair, a)
 }
 
 // DecodeAccountClaims decodes account claims from a JWT string

v2/activation_claims.go

@@ -82,7 +82,7 @@ func (a *ActivationClaims) Encode(pair nkeys.KeyPair) (string, error) {
 		return "", errors.New("expected subject to be an account")
 	}
 	a.Type = ActivationClaim
-	return a.ClaimsData.Encode(pair, a)
+	return a.ClaimsData.encode(pair, a)
 }
 
 // DecodeActivationClaims tries to create an activation claim from a JWT string

v2/claims.go

@@ -49,8 +49,9 @@ type Claims interface {
 	Payload() interface{}
 	String() string
 	Validate(vr *ValidationResults)
-	Verify(payload string, sig []byte) bool
 	ClaimType() ClaimType
+
+	verify(payload string, sig []byte) bool
 	updateVersion()
 }
 
@@ -102,6 +103,10 @@ func (c *ClaimsData) doEncode(header *Header, kp nkeys.KeyPair, claim Claims) (s
 		return "", errors.New("keypair is required")
 	}
 
+	if c != claim.Claims() {
+		return "", errors.New("claim and claim data do not match")
+	}
+
 	if c.Subject == "" {
 		return "", errors.New("subject is not set")
 	}
@@ -150,7 +155,7 @@ func (c *ClaimsData) doEncode(header *Header, kp nkeys.KeyPair, claim Claims) (s
 
 	c.Issuer = issuerBytes
 	c.IssuedAt = time.Now().UTC().Unix()
-
+	c.ID = "" // to create a repeatable hash
 	c.ID, err = c.hash()
 	if err != nil {
 		return "", err
@@ -163,12 +168,21 @@ func (c *ClaimsData) doEncode(header *Header, kp nkeys.KeyPair, claim Claims) (s
 		return "", err
 	}
 
-	sig, err := kp.Sign([]byte(payload))
-	if err != nil {
-		return "", err
+	toSign := fmt.Sprintf("%s.%s", h, payload)
+	eSig := ""
+	if header.Algorithm == AlgorithmNkeyOld {
+		return "", errors.New(AlgorithmNkeyOld + " not supported to write jwtV2")
+	} else if header.Algorithm == AlgorithmNkey {
+		sig, err := kp.Sign([]byte(toSign))
+		if err != nil {
+			return "", err
+		}
+		eSig = encodeToString(sig)
+	} else {
+		return "", errors.New(header.Algorithm + " not supported to write jwtV2")
 	}
-	eSig := encodeToString(sig)
-	return fmt.Sprintf("%s.%s.%s", h, payload, eSig), nil
+	// hash need no padding
+	return fmt.Sprintf("%s.%s", toSign, eSig), nil
 }
 
 func (c *ClaimsData) hash() (string, error) {
@@ -183,7 +197,7 @@ func (c *ClaimsData) hash() (string, error) {
 
 // Encode encodes a claim into a JWT token. The claim is signed with the
 // provided nkey's private key
-func (c *ClaimsData) Encode(kp nkeys.KeyPair, payload Claims) (string, error) {
+func (c *ClaimsData) encode(kp nkeys.KeyPair, payload Claims) (string, error) {
 	return c.doEncode(&Header{TokenTypeJwt, AlgorithmNkey}, kp, payload)
 }
 
@@ -209,7 +223,7 @@ func parseClaims(s string, target Claims) error {
 // the claims portion of the token and the public key in the claim.
 // Client code need to insure that the public key in the
 // claim is trusted.
-func (c *ClaimsData) Verify(payload string, sig []byte) bool {
+func (c *ClaimsData) verify(payload string, sig []byte) bool {
 	// decode the public key
 	kp, err := nkeys.FromPublicKey(c.Issuer)
 	if err != nil {

v2/decoder.go

@@ -71,7 +71,7 @@ func Decode(token string) (Claims, error) {
 	if err != nil {
 		return nil, err
 	}
-	claim, err := loadClaims(data)
+	ver, claim, err := loadClaims(data)
 	if err != nil {
 		return nil, err
 	}
@@ -81,8 +81,15 @@ func Decode(token string) (Claims, error) {
 	if err != nil {
 		return nil, err
 	}
-	if !claim.Verify(chunks[1], sig) {
-		return nil, errors.New("claim failed signature verification")
+
+	if ver <= 1 {
+		if !claim.verify(chunks[1], sig) {
+			return nil, errors.New("claim failed V1 signature verification")
+		}
+	} else {
+		if !claim.verify(token[:len(chunks[0])+len(chunks[1])+1], sig) {
+			return nil, errors.New("claim failed V2 signature verification")
+		}
 	}
 
 	prefixes := claim.ExpectedPrefixes()
@@ -112,14 +119,14 @@ func Decode(token string) (Claims, error) {
 	return claim, nil
 }
 
-func loadClaims(data []byte) (Claims, error) {
+func loadClaims(data []byte) (int, Claims, error) {
 	var id identifier
 	if err := json.Unmarshal(data, &id); err != nil {
-		return nil, err
+		return -1, nil, err
 	}
 
 	if id.Version() > libVersion {
-		return nil, errors.New("JWT was generated by a newer version ")
+		return -1, nil, errors.New("JWT was generated by a newer version ")
 	}
 
 	var claim Claims
@@ -134,16 +141,16 @@ func loadClaims(data []byte) (Claims, error) {
 	case ActivationClaim:
 		claim, err = loadActivation(data, id.Version())
 	case "cluster":
-		return nil, errors.New("ClusterClaims are not supported")
+		return -1, nil, errors.New("ClusterClaims are not supported")
 	case "server":
-		return nil, errors.New("ServerClaims are not supported")
+		return -1, nil, errors.New("ServerClaims are not supported")
 	default:
 		var gc GenericClaims
 		if err := json.Unmarshal(data, &gc); err != nil {
-			return nil, err
+			return -1, nil, err
 		}
-		return &gc, nil
+		return -1, &gc, nil
 	}
 
-	return claim, err
+	return id.Version(), claim, err
 }

v2/decoder_test.go

@@ -97,22 +97,16 @@ func TestBadAlgo(t *testing.T) {
 	c := NewGenericClaims(publicKey(createUserNKey(t), t))
 	c.Data["foo"] = "bar"
 
-	token, err := c.doEncode(&h, kp, c)
-	if err != nil {
-		t.Fatal(err)
+	if _, err := c.doEncode(&h, kp, c); err == nil {
+		t.Fatal("expected an error due to bad algorithm")
 	}
 
-	claim, err := DecodeGeneric(token)
-	if claim != nil {
-		t.Fatal("non nil claim on bad token")
-	}
-
-	if err == nil {
-		t.Fatal("nil error on bad token")
-	}
+	h = Header{TokenTypeJwt, AlgorithmNkeyOld}
+	c = NewGenericClaims(publicKey(createUserNKey(t), t))
+	c.Data["foo"] = "bar"
 
-	if err.Error() != fmt.Sprintf("unexpected %q algorithm", "foobar") {
-		t.Fatal("expected unexpected algorithm")
+	if _, err := c.doEncode(&h, kp, c); err == nil {
+		t.Fatal("expected an error due to bad algorithm")
 	}
 }
 
@@ -150,30 +144,33 @@ func TestBadJWT(t *testing.T) {
 
 func TestBadSignature(t *testing.T) {
 	kp := createAccountNKey(t)
-
-	h := Header{TokenTypeJwt, AlgorithmNkey}
-	c := NewGenericClaims(publicKey(createUserNKey(t), t))
-	c.Data["foo"] = "bar"
-
-	token, err := c.doEncode(&h, kp, c)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	token = token + "A"
-
-	claim, err := DecodeGeneric(token)
-	if claim != nil {
-		t.Fatal("non nil claim on bad token")
-	}
-
-	if err == nil {
-		t.Fatal("nil error on bad token")
-	}
-
-	if err.Error() != "claim failed signature verification" {
-		m := fmt.Sprintf("expected failed signature: %q", err.Error())
-		t.Fatal(m)
+	for algo, error := range map[string]string{
+		AlgorithmNkey: "claim failed V2 signature verification",
+	} {
+		h := Header{TokenTypeJwt, algo}
+		c := NewGenericClaims(publicKey(createUserNKey(t), t))
+		c.Data["foo"] = "bar"
+
+		token, err := c.doEncode(&h, kp, c)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		token = token + "A"
+
+		claim, err := DecodeGeneric(token)
+		if claim != nil {
+			t.Fatal("non nil claim on bad token")
+		}
+
+		if err == nil {
+			t.Fatal("nil error on bad token")
+		}
+
+		if err.Error() != error {
+			m := fmt.Sprintf("expected failed signature: %q", err.Error())
+			t.Fatal(m)
+		}
 	}
 }
 
@@ -201,7 +198,7 @@ func TestDifferentPayload(t *testing.T) {
 		t.Fatal("nil error on bad token")
 	}
 
-	if err.Error() != "claim failed signature verification" {
+	if err.Error() != "claim failed V2 signature verification" {
 		m := fmt.Sprintf("expected failed signature: %q", err.Error())
 		t.Fatal(m)
 	}
@@ -332,7 +329,7 @@ func TestBadClaimsJSON(t *testing.T) {
 func TestBadPublicKeyDecodeGeneric(t *testing.T) {
 	c := &GenericClaims{}
 	c.Issuer = "foo"
-	if ok := c.Verify("foo", []byte("bar")); ok {
+	if ok := c.verify("foo", []byte("bar")); ok {
 		t.Fatal("Should have failed to verify")
 	}
 }

v2/genericlaims.go

@@ -49,7 +49,8 @@ func DecodeGeneric(token string) (*GenericClaims, error) {
 	}
 
 	// header
-	if _, err := parseHeaders(chunks[0]); err != nil {
+	header, err := parseHeaders(chunks[0])
+	if err != nil {
 		return nil, err
 	}
 	// claim
@@ -68,10 +69,16 @@ func DecodeGeneric(token string) (*GenericClaims, error) {
 	if err != nil {
 		return nil, err
 	}
-	if !gc.Verify(chunks[1], sig) {
-		return nil, errors.New("claim failed signature verification")
-	}
 
+	if header.Algorithm == AlgorithmNkeyOld {
+		if !gc.verify(chunks[1], sig) {
+			return nil, errors.New("claim failed V1 signature verification")
+		}
+	} else {
+		if !gc.verify(token[:len(chunks[0])+len(chunks[1])+1], sig) {
+			return nil, errors.New("claim failed V2 signature verification")
+		}
+	}
 	return &gc, nil
 }
 
@@ -87,7 +94,7 @@ func (gc *GenericClaims) Payload() interface{} {
 
 // Encode takes a generic claims and creates a JWT string
 func (gc *GenericClaims) Encode(pair nkeys.KeyPair) (string, error) {
-	return gc.ClaimsData.Encode(pair, gc)
+	return gc.ClaimsData.encode(pair, gc)
 }
 
 // Validate checks the generic part of the claims data
@@ -123,11 +130,8 @@ func (gc *GenericClaims) ClaimType() ClaimType {
 }
 
 func (gc *GenericClaims) updateVersion() {
-	v, ok := gc.Data["nats"]
-	if ok {
-		m, ok := v.(map[string]interface{})
-		if ok {
-			m["version"] = libVersion
-		}
+	if gc.Data != nil {
+		// store as float as that is what decoding with json does too
+		gc.Data["version"] = float64(libVersion)
 	}
 }

v2/header.go

@@ -27,7 +27,9 @@ const (
 
 	// TokenTypeJwt is the JWT token type supported JWT tokens
 	// encoded and decoded by this library
-	TokenTypeJwt = "jwt"
+	// from RFC7519 5.1 "typ":
+	// it is RECOMMENDED that "JWT" always be spelled using uppercase characters for compatibility
+	TokenTypeJwt = "JWT"
 
 	// AlgorithmNkey is the algorithm supported by JWT tokens
 	// encoded and decoded by this library
@@ -61,7 +63,7 @@ func parseHeaders(s string) (*Header, error) {
 // Valid validates the Header. It returns nil if the Header is
 // a JWT header, and the algorithm used is the NKEY algorithm.
 func (h *Header) Valid() error {
-	if TokenTypeJwt != strings.ToLower(h.Type) {
+	if TokenTypeJwt != strings.ToUpper(h.Type) {
 		return fmt.Errorf("not supported type %q", h.Type)
 	}
 

v2/operator_claims.go

@@ -195,7 +195,7 @@ func (oc *OperatorClaims) Encode(pair nkeys.KeyPair) (string, error) {
 		return "", err
 	}
 	oc.Type = OperatorClaim
-	return oc.ClaimsData.Encode(pair, oc)
+	return oc.ClaimsData.encode(pair, oc)
 }
 
 func (oc *OperatorClaims) ClaimType() ClaimType {

v2/user_claims.go

@@ -65,7 +65,7 @@ func (u *UserClaims) Encode(pair nkeys.KeyPair) (string, error) {
 		return "", errors.New("expected subject to be user public key")
 	}
 	u.Type = UserClaim
-	return u.ClaimsData.Encode(pair, u)
+	return u.ClaimsData.encode(pair, u)
 }
 
 // DecodeUserClaims tries to parse a user claims from a JWT string