Merge pull request #125 from shaxbee/nested-jwt

Support creating and parsing nested JWTs

Author: csstaub

crypter.go

@@ -28,6 +28,7 @@ import (
 type Encrypter interface {
 	Encrypt(plaintext []byte) (*JSONWebEncryption, error)
 	EncryptWithAuthData(plaintext []byte, aad []byte) (*JSONWebEncryption, error)
+	Options() EncrypterOptions
 }
 
 // A generic content cipher
@@ -57,6 +58,7 @@ type keyDecrypter interface {
 type genericEncrypter struct {
 	contentAlg     ContentEncryption
 	compressionAlg CompressionAlgorithm
+	contentType    ContentType
 	cipher         contentCipher
 	recipients     []recipientKeyInfo
 	keyGenerator   keyGenerator
@@ -71,6 +73,7 @@ type recipientKeyInfo struct {
 // EncrypterOptions represents options that can be set on new encrypters.
 type EncrypterOptions struct {
 	Compression CompressionAlgorithm
+	ContentType ContentType
 }
 
 // Recipient represents an algorithm/key to encrypt messages to.
@@ -89,6 +92,7 @@ func NewEncrypter(enc ContentEncryption, rcpt Recipient, opts *EncrypterOptions)
 	}
 	if opts != nil {
 		encrypter.compressionAlg = opts.Compression
+		encrypter.contentType = opts.ContentType
 	}
 
 	if encrypter.cipher == nil {
@@ -256,6 +260,7 @@ func (ctx *genericEncrypter) EncryptWithAuthData(plaintext, aad []byte) (*JSONWe
 
 	obj.protected = &rawHeader{
 		Enc: ctx.contentAlg,
+		Cty: string(ctx.contentType),
 	}
 	obj.recipients = make([]recipientInfo, len(ctx.recipients))
 
@@ -312,6 +317,13 @@ func (ctx *genericEncrypter) EncryptWithAuthData(plaintext, aad []byte) (*JSONWe
 	return obj, nil
 }
 
+func (ctx *genericEncrypter) Options() EncrypterOptions {
+	return EncrypterOptions{
+		Compression: ctx.compressionAlg,
+		ContentType: ctx.contentType,
+	}
+}
+
 // Decrypt and validate the object and return the plaintext. Note that this
 // function does not support multi-recipient, if you desire multi-recipient
 // decryption use DecryptMulti instead.

jwt/builder.go

@@ -39,6 +39,21 @@ type Builder interface {
 	CompactSerialize() (string, error)
 }
 
+// NestedBuilder is a utility for making Signed-Then-Encrypted JSON Web Tokens.
+// Calls can be chained, and errors are accumulated until final call to
+// CompactSerialize/FullSerialize.
+type NestedBuilder interface {
+	// Claims encodes claims into JWE/JWS form. Multiple calls will merge claims
+	// into single JSON object.
+	Claims(i interface{}) NestedBuilder
+	// Token builds a NestedJSONWebToken from provided data.
+	Token() (*NestedJSONWebToken, error)
+	// FullSerialize serializes a token using the full serialization format.
+	FullSerialize() (string, error)
+	// CompactSerialize serializes a token using the compact serialization format.
+	CompactSerialize() (string, error)
+}
+
 type builder struct {
 	payload map[string]interface{}
 	err     error
@@ -54,6 +69,12 @@ type encryptedBuilder struct {
 	enc jose.Encrypter
 }
 
+type nestedBuilder struct {
+	builder
+	sig jose.Signer
+	enc jose.Encrypter
+}
+
 // Signed creates builder for signed tokens.
 func Signed(sig jose.Signer) Builder {
 	return &signedBuilder{
@@ -68,6 +89,22 @@ func Encrypted(enc jose.Encrypter) Builder {
 	}
 }
 
+// SignedAndEncrypted creates builder for signed-then-encrypted tokens.
+// ErrInvalidContentType will be returned if encrypter doesn't have JWT content type.
+func SignedAndEncrypted(sig jose.Signer, enc jose.Encrypter) NestedBuilder {
+	if enc.Options().ContentType != "JWT" {
+		return &nestedBuilder{
+			builder: builder{
+				err: ErrInvalidContentType,
+			},
+		}
+	}
+	return &nestedBuilder{
+		sig: sig,
+		enc: enc,
+	}
+}
+
 func (b builder) claims(i interface{}) builder {
 	if b.err != nil {
 		return b
@@ -225,3 +262,64 @@ func (b *encryptedBuilder) encrypt() (*jose.JSONWebEncryption, error) {
 
 	return b.enc.Encrypt(p)
 }
+
+func (b *nestedBuilder) Claims(i interface{}) NestedBuilder {
+	return &nestedBuilder{
+		builder: b.builder.claims(i),
+		sig:     b.sig,
+		enc:     b.enc,
+	}
+}
+
+func (b *nestedBuilder) Token() (*NestedJSONWebToken, error) {
+	enc, err := b.signAndEncrypt()
+	if err != nil {
+		return nil, err
+	}
+
+	return &NestedJSONWebToken{
+		enc:     enc,
+		Headers: []jose.Header{enc.Header},
+	}, nil
+}
+
+func (b *nestedBuilder) CompactSerialize() (string, error) {
+	enc, err := b.signAndEncrypt()
+	if err != nil {
+		return "", err
+	}
+
+	return enc.CompactSerialize()
+}
+
+func (b *nestedBuilder) FullSerialize() (string, error) {
+	enc, err := b.signAndEncrypt()
+	if err != nil {
+		return "", err
+	}
+
+	return enc.FullSerialize(), nil
+}
+
+func (b *nestedBuilder) signAndEncrypt() (*jose.JSONWebEncryption, error) {
+	if b.err != nil {
+		return nil, b.err
+	}
+
+	p, err := json.Marshal(b.payload)
+	if err != nil {
+		return nil, err
+	}
+
+	sig, err := b.sig.Sign(p)
+	if err != nil {
+		return nil, err
+	}
+
+	p2, err := sig.CompactSerialize()
+	if err != nil {
+		return nil, err
+	}
+
+	return b.enc.Encrypt([]byte(p2))
+}

jwt/builder_test.go

@@ -179,6 +179,61 @@ func TestEncryptedFullSerializeAndToken(t *testing.T) {
 	require.EqualError(t, err, "json: error calling MarshalJSON for type *jwt.invalidMarshalClaims: Failed marshaling invalid claims.")
 }
 
+func TestBuilderSignedAndEncrypted(t *testing.T) {
+	recipient := jose.Recipient{
+		Algorithm: jose.RSA1_5,
+		Key:       testPrivRSAKey1.Public(),
+	}
+	encrypter, err := jose.NewEncrypter(jose.A128CBC_HS256, recipient, &jose.EncrypterOptions{
+		ContentType: "JWT",
+	})
+	require.NoError(t, err, "Error creating encrypter.")
+
+	jwt1, err := SignedAndEncrypted(rsaSigner, encrypter).Claims(&testClaims{"foo"}).Token()
+	require.NoError(t, err, "Error marshaling signed-then-encrypted token.")
+	if nested, err := jwt1.Decrypt(testPrivRSAKey1); assert.NoError(t, err, "Error decrypting signed-then-encrypted token.") {
+		out := &testClaims{}
+		assert.NoError(t, nested.Claims(&testPrivRSAKey1.PublicKey, out))
+		assert.Equal(t, &testClaims{"foo"}, out)
+	}
+
+	b := SignedAndEncrypted(rsaSigner, encrypter).Claims(&testClaims{"foo"})
+	tok1, err := b.CompactSerialize()
+	if assert.NoError(t, err) {
+		jwt, err := ParseSignedAndEncrypted(tok1)
+		if assert.NoError(t, err, "Error parsing signed-then-encrypted compact token.") {
+			if nested, err := jwt.Decrypt(testPrivRSAKey1); assert.NoError(t, err) {
+				out := &testClaims{}
+				assert.NoError(t, nested.Claims(&testPrivRSAKey1.PublicKey, out))
+				assert.Equal(t, &testClaims{"foo"}, out)
+			}
+		}
+	}
+
+	tok2, err := b.FullSerialize()
+	if assert.NoError(t, err) {
+		jwt, err := ParseSignedAndEncrypted(tok2)
+		if assert.NoError(t, err, "Error parsing signed-then-encrypted full token.") {
+			if nested, err := jwt.Decrypt(testPrivRSAKey1); assert.NoError(t, err) {
+				out := &testClaims{}
+				assert.NoError(t, nested.Claims(&testPrivRSAKey1.PublicKey, out))
+				assert.Equal(t, &testClaims{"foo"}, out)
+			}
+		}
+	}
+
+	b2 := SignedAndEncrypted(rsaSigner, encrypter).Claims(&invalidMarshalClaims{})
+	_, err = b2.CompactSerialize()
+	assert.EqualError(t, err, "json: error calling MarshalJSON for type *jwt.invalidMarshalClaims: Failed marshaling invalid claims.")
+	_, err = b2.FullSerialize()
+	assert.EqualError(t, err, "json: error calling MarshalJSON for type *jwt.invalidMarshalClaims: Failed marshaling invalid claims.")
+
+	encrypter2, err := jose.NewEncrypter(jose.A128CBC_HS256, recipient, nil)
+	require.NoError(t, err, "Error creating encrypter.")
+	_, err = SignedAndEncrypted(rsaSigner, encrypter2).CompactSerialize()
+	assert.EqualError(t, err, "square/go-jose/jwt: expected content type to be JWT (cty header)")
+}
+
 func TestBuilderHeadersSigner(t *testing.T) {
 	tests := []struct {
 		Keys   []*rsa.PrivateKey

jwt/errors.go

@@ -45,3 +45,6 @@ var ErrNotValidYet = errors.New("square/go-jose/jwt: validation failed, token no
 
 // ErrExpired indicates that token is used after expiry time indicated in exp claim.
 var ErrExpired = errors.New("square/go-jose/jwt: validation failed, token is expired (exp)")
+
+// ErrInvalidContentType indicated that token requires JWT cty header.
+var ErrInvalidContentType = errors.New("square/go-jose/jwt: expected content type to be JWT (cty header)")

jwt/example_test.go

@@ -22,6 +22,9 @@ import (
 	"strings"
 	"time"
 
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
 	"gopkg.in/square/go-jose.v2"
 	"gopkg.in/square/go-jose.v2/jwt"
 )
@@ -58,7 +61,28 @@ func ExampleParseEncrypted() {
 		panic(err)
 	}
 	fmt.Printf("iss: %s, sub: %s\n", out.Issuer, out.Subject)
-	//Output: iss: issuer, sub: subject
+	// Output: iss: issuer, sub: subject
+}
+
+func ExampleParseSignedAndEncrypted() {
+	raw := `eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIiwiY3R5IjoiSldUIn0..-keV-9YpsxotBEHw.yC9SHWgnkjykgJqXZGlzYC5Wg_EdWKO5TgfqeqsWWJYw7fX9zXQE3NtXmA3nAiUrYOr3H2s0AgTeAhTNbELLEHQu0blfRaPa_uKOAgFgmhJwbGe2iFLn9J0U72wk56318nI-pTLCV8FijoGpXvAxQlaKrPLKkl9yDQimPhb7UiDwLWYkJeoayciAXhR5f40E8ORGjCz8oawXRvjDaSjgRElUwy4kMGzvJy_difemEh4lfMSIwUNVEqJkEYaalRttSymMYuV6NvBVU0N0Jb6omdM4tW961OySB4KPWCWH9UJUX0XSEcqbW9WLxpg3ftx5R7xNiCnaVaCx_gJZfXJ9yFLqztIrKh2N05zHM0tddSOwCOnq7_1rJtaVz0nTXjSjf1RrVaxJya59p3K-e41QutiGFiJGzXG-L2OyLETIaVSU3ptvaCz4IxCF3GzeCvOgaICvXkpBY1-bv-fk1ilyjmcTDnLp2KivWIxcnoQmpN9xj06ZjagdG09AHUhS5WixADAg8mIdGcanNblALecnCWG-otjM9Kw.RZoaHtSgnzOin2od3D9tnA`
+	tok, err := jwt.ParseSignedAndEncrypted(raw)
+	if err != nil {
+		panic(err)
+	}
+
+	nested, err := tok.Decrypt(sharedEncryptionKey)
+	if err != nil {
+		panic(err)
+	}
+
+	out := jwt.Claims{}
+	if err := nested.Claims(&rsaPrivKey.PublicKey, &out); err != nil {
+		panic(err)
+	}
+
+	fmt.Printf("iss: %s, sub: %s\n", out.Issuer, out.Subject)
+	// Output: iss: issuer, sub: subject
 }
 
 func ExampleClaims_Validate() {
@@ -146,6 +170,32 @@ func ExampleEncrypted() {
 	fmt.Println(raw)
 }
 
+func ExampleSignedAndEncrypted() {
+	enc, err := jose.NewEncrypter(
+		jose.A128GCM,
+		jose.Recipient{
+			Algorithm: jose.DIRECT,
+			Key:       sharedEncryptionKey,
+		},
+		&jose.EncrypterOptions{
+			ContentType: "JWT",
+		})
+	if err != nil {
+		panic(err)
+	}
+
+	cl := jwt.Claims{
+		Subject: "subject",
+		Issuer:  "issuer",
+	}
+	raw, err := jwt.SignedAndEncrypted(rsaSigner, enc).Claims(cl).CompactSerialize()
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(raw)
+}
+
 func ExampleSigned_multipleClaims() {
 	c := &jwt.Claims{
 		Subject: "subject",
@@ -198,3 +248,58 @@ func ExampleJSONWebToken_Claims_multiple() {
 	fmt.Printf("iss: %s, sub: %s, scopes: %s\n", out.Issuer, out.Subject, strings.Join(out2.Scopes, ","))
 	// Output: iss: issuer, sub: subject, scopes: foo,bar
 }
+
+func mustUnmarshalRSA(data string) *rsa.PrivateKey {
+	block, _ := pem.Decode([]byte(data))
+	if block == nil {
+		panic("failed to decode PEM data")
+	}
+	key, err := x509.ParsePKCS8PrivateKey(block.Bytes)
+	if err != nil {
+		panic("failed to parse RSA key: " + err.Error())
+	}
+	if key, ok := key.(*rsa.PrivateKey); ok {
+		return key
+	}
+	panic("key is not of type *rsa.PrivateKey")
+}
+
+func mustMakeSigner(alg jose.SignatureAlgorithm, k interface{}) jose.Signer {
+	sig, err := jose.NewSigner(jose.SigningKey{Algorithm: alg, Key: k}, nil)
+	if err != nil {
+		panic("failed to create signer:" + err.Error())
+	}
+
+	return sig
+}
+
+var rsaPrivKey = mustUnmarshalRSA(`-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----`)
+
+var rsaSigner = mustMakeSigner(jose.RS256, rsaPrivKey)