Add RSASSA-PSS signatures

rsa_pss.go

@@ -0,0 +1,126 @@
+// +build go1.4
+
+package jwt
+
+import (
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+)
+
+// Implements the RSAPSS family of signing methods signing methods
+type SigningMethodRSAPSS struct {
+	*SigningMethodRSA
+	Options *rsa.PSSOptions
+}
+
+// Specific instances for RS/PS and company
+var (
+	SigningMethodPS256 *SigningMethodRSAPSS
+	SigningMethodPS384 *SigningMethodRSAPSS
+	SigningMethodPS512 *SigningMethodRSAPSS
+)
+
+func init() {
+	// PS256
+	SigningMethodPS256 = &SigningMethodRSAPSS{
+		&SigningMethodRSA{
+			Name: "PS256",
+			Hash: crypto.SHA256,
+		},
+		&rsa.PSSOptions{
+			SaltLength: rsa.PSSSaltLengthAuto,
+			Hash:       crypto.SHA256,
+		},
+	}
+	RegisterSigningMethod(SigningMethodPS256.Alg(), func() SigningMethod {
+		return SigningMethodPS256
+	})
+
+	// PS384
+	SigningMethodPS384 = &SigningMethodRSAPSS{
+		&SigningMethodRSA{
+			Name: "PS384",
+			Hash: crypto.SHA384,
+		},
+		&rsa.PSSOptions{
+			SaltLength: rsa.PSSSaltLengthAuto,
+			Hash:       crypto.SHA384,
+		},
+	}
+	RegisterSigningMethod(SigningMethodPS384.Alg(), func() SigningMethod {
+		return SigningMethodPS384
+	})
+
+	// PS512
+	SigningMethodPS512 = &SigningMethodRSAPSS{
+		&SigningMethodRSA{
+			Name: "PS512",
+			Hash: crypto.SHA512,
+		},
+		&rsa.PSSOptions{
+			SaltLength: rsa.PSSSaltLengthAuto,
+			Hash:       crypto.SHA512,
+		},
+	}
+	RegisterSigningMethod(SigningMethodPS512.Alg(), func() SigningMethod {
+		return SigningMethodPS512
+	})
+}
+
+// Implements the Verify method from SigningMethod
+// For this verify method, key must be an rsa.PrivateKey struct
+func (m *SigningMethodRSAPSS) Verify(signingString, signature string, key interface{}) error {
+	var err error
+
+	// Decode the signature
+	var sig []byte
+	if sig, err = DecodeSegment(signature); err != nil {
+		return err
+	}
+
+	var rsaKey *rsa.PublicKey
+	switch k := key.(type) {
+	case *rsa.PublicKey:
+		rsaKey = k
+	default:
+		return ErrInvalidKey
+	}
+
+	// Create hasher
+	if !m.Hash.Available() {
+		return ErrHashUnavailable
+	}
+	hasher := m.Hash.New()
+	hasher.Write([]byte(signingString))
+
+	return rsa.VerifyPSS(rsaKey, m.Hash, hasher.Sum(nil), sig, m.Options)
+}
+
+// Implements the Sign method from SigningMethod
+// For this signing method, key must be an rsa.PublicKey struct
+func (m *SigningMethodRSAPSS) Sign(signingString string, key interface{}) (string, error) {
+	var rsaKey *rsa.PrivateKey
+
+	switch k := key.(type) {
+	case *rsa.PrivateKey:
+		rsaKey = k
+	default:
+		return "", ErrInvalidKey
+	}
+
+	// Create the hasher
+	if !m.Hash.Available() {
+		return "", ErrHashUnavailable
+	}
+
+	hasher := m.Hash.New()
+	hasher.Write([]byte(signingString))
+
+	// Sign the string and return the encoded bytes
+	if sigBytes, err := rsa.SignPSS(rand.Reader, rsaKey, m.Hash, hasher.Sum(nil), m.Options); err == nil {
+		return EncodeSegment(sigBytes), nil
+	} else {
+		return "", err
+	}
+}

rsa_pss_test.go

@@ -0,0 +1,96 @@
+// +build go1.4
+
+package jwt_test
+
+import (
+	"crypto/rsa"
+	"io/ioutil"
+	"strings"
+	"testing"
+
+	"github.com/dgrijalva/jwt-go"
+)
+
+var rsaPSSTestData = []struct {
+	name        string
+	tokenString string
+	alg         string
+	claims      map[string]interface{}
+	valid       bool
+}{
+	{
+		"Basic PS256",
+		"eyJhbGciOiJQUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIifQ.PPG4xyDVY8ffp4CcxofNmsTDXsrVG2npdQuibLhJbv4ClyPTUtR5giNSvuxo03kB6I8VXVr0Y9X7UxhJVEoJOmULAwRWaUsDnIewQa101cVhMa6iR8X37kfFoiZ6NkS-c7henVkkQWu2HtotkEtQvN5hFlk8IevXXPmvZlhQhwzB1sGzGYnoi1zOfuL98d3BIjUjtlwii5w6gYG2AEEzp7HnHCsb3jIwUPdq86Oe6hIFjtBwduIK90ca4UqzARpcfwxHwVLMpatKask00AgGVI0ysdk0BLMjmLutquD03XbThHScC2C2_Pp4cHWgMzvbgLU2RYYZcZRKr46QeNgz9w",
+		"PS256",
+		map[string]interface{}{"foo": "bar"},
+		true,
+	},
+	{
+		"Basic PS384",
+		"eyJhbGciOiJQUzM4NCIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIifQ.w7-qqgj97gK4fJsq_DCqdYQiylJjzWONvD0qWWWhqEOFk2P1eDULPnqHRnjgTXoO4HAw4YIWCsZPet7nR3Xxq4ZhMqvKW8b7KlfRTb9cH8zqFvzMmybQ4jv2hKc3bXYqVow3AoR7hN_CWXI3Dv6Kd2X5xhtxRHI6IL39oTVDUQ74LACe-9t4c3QRPuj6Pq1H4FAT2E2kW_0KOc6EQhCLWEhm2Z2__OZskDC8AiPpP8Kv4k2vB7l0IKQu8Pr4RcNBlqJdq8dA5D3hk5TLxP8V5nG1Ib80MOMMqoS3FQvSLyolFX-R_jZ3-zfq6Ebsqr0yEb0AH2CfsECF7935Pa0FKQ",
+		"PS384",
+		map[string]interface{}{"foo": "bar"},
+		true,
+	},
+	{
+		"Basic PS512",
+		"eyJhbGciOiJQUzUxMiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIifQ.GX1HWGzFaJevuSLavqqFYaW8_TpvcjQ8KfC5fXiSDzSiT9UD9nB_ikSmDNyDILNdtjZLSvVKfXxZJqCfefxAtiozEDDdJthZ-F0uO4SPFHlGiXszvKeodh7BuTWRI2wL9-ZO4mFa8nq3GMeQAfo9cx11i7nfN8n2YNQ9SHGovG7_T_AvaMZB_jT6jkDHpwGR9mz7x1sycckEo6teLdHRnH_ZdlHlxqknmyTu8Odr5Xh0sJFOL8BepWbbvIIn-P161rRHHiDWFv6nhlHwZnVzjx7HQrWSGb6-s2cdLie9QL_8XaMcUpjLkfOMKkDOfHo6AvpL7Jbwi83Z2ZTHjJWB-A",
+		"PS512",
+		map[string]interface{}{"foo": "bar"},
+		true,
+	},
+	{
+		"basic PS256 invalid: foo => bar",
+		"eyJhbGciOiJQUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIifQ.PPG4xyDVY8ffp4CcxofNmsTDXsrVG2npdQuibLhJbv4ClyPTUtR5giNSvuxo03kB6I8VXVr0Y9X7UxhJVEoJOmULAwRWaUsDnIewQa101cVhMa6iR8X37kfFoiZ6NkS-c7henVkkQWu2HtotkEtQvN5hFlk8IevXXPmvZlhQhwzB1sGzGYnoi1zOfuL98d3BIjUjtlwii5w6gYG2AEEzp7HnHCsb3jIwUPdq86Oe6hIFjtBwduIK90ca4UqzARpcfwxHwVLMpatKask00AgGVI0ysdk0BLMjmLutquD03XbThHScC2C2_Pp4cHWgMzvbgLU2RYYZcZRKr46QeNgz9W",
+		"PS256",
+		map[string]interface{}{"foo": "bar"},
+		false,
+	},
+}
+
+func TestRSAPSSVerify(t *testing.T) {
+	var err error
+
+	key, _ := ioutil.ReadFile("test/sample_key.pub")
+	var rsaPSSKey *rsa.PublicKey
+	if rsaPSSKey, err = jwt.ParseRSAPublicKeyFromPEM(key); err != nil {
+		t.Errorf("Unable to parse RSA public key: %v", err)
+	}
+
+	for _, data := range rsaPSSTestData {
+		parts := strings.Split(data.tokenString, ".")
+
+		method := jwt.GetSigningMethod(data.alg)
+		err := method.Verify(strings.Join(parts[0:2], "."), parts[2], rsaPSSKey)
+		if data.valid && err != nil {
+			t.Errorf("[%v] Error while verifying key: %v", data.name, err)
+		}
+		if !data.valid && err == nil {
+			t.Errorf("[%v] Invalid key passed validation", data.name)
+		}
+	}
+}
+
+func TestRSAPSSSign(t *testing.T) {
+	var err error
+
+	key, _ := ioutil.ReadFile("test/sample_key")
+	var rsaPSSKey *rsa.PrivateKey
+	if rsaPSSKey, err = jwt.ParseRSAPrivateKeyFromPEM(key); err != nil {
+		t.Errorf("Unable to parse RSA private key: %v", err)
+	}
+
+	for _, data := range rsaPSSTestData {
+		if data.valid {
+			parts := strings.Split(data.tokenString, ".")
+			method := jwt.GetSigningMethod(data.alg)
+			sig, err := method.Sign(strings.Join(parts[0:2], "."), rsaPSSKey)
+			if err != nil {
+				t.Errorf("[%v] Error signing token: %v", data.name, err)
+			}
+			if sig == parts[2] {
+				t.Errorf("[%v] Signatures shouldn't match\nnew:\n%v\noriginal:\n%v", data.name, sig, parts[2])
+			}
+		}
+	}
+}