1 files changed, 343 insertions, 0 deletions
diff --git a/vendor/gopkg.in/square/go-jose.v2/signing.go b/vendor/gopkg.in/square/go-jose.v2/signing.go
new file mode 100644
index 000000000..13e956d66
--- /dev/null
+++ b/vendor/gopkg.in/square/go-jose.v2/signing.go
@@ -0,0 +1,343 @@
+/*-
+ * Copyright 2014 Square Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package jose
+
+import (
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"encoding/base64"
+	"errors"
+	"fmt"
+
+	"golang.org/x/crypto/ed25519"
+
+	"gopkg.in/square/go-jose.v2/json"
+)
+
+// NonceSource represents a source of random nonces to go into JWS objects
+type NonceSource interface {
+	Nonce() (string, error)
+}
+
+// Signer represents a signer which takes a payload and produces a signed JWS object.
+type Signer interface {
+	Sign(payload []byte) (*JSONWebSignature, error)
+	Options() SignerOptions
+}
+
+// SigningKey represents an algorithm/key used to sign a message.
+type SigningKey struct {
+	Algorithm SignatureAlgorithm
+	Key       interface{}
+}
+
+// SignerOptions represents options that can be set when creating signers.
+type SignerOptions struct {
+	NonceSource NonceSource
+	EmbedJWK    bool
+
+	// Optional map of additional keys to be inserted into the protected header
+	// of a JWS object. Some specifications which make use of JWS like to insert
+	// additional values here. All values must be JSON-serializable.
+	ExtraHeaders map[HeaderKey]interface{}
+}
+
+// WithHeader adds an arbitrary value to the ExtraHeaders map, initializing it
+// if necessary. It returns itself and so can be used in a fluent style.
+func (so *SignerOptions) WithHeader(k HeaderKey, v interface{}) *SignerOptions {
+	if so.ExtraHeaders == nil {
+		so.ExtraHeaders = map[HeaderKey]interface{}{}
+	}
+	so.ExtraHeaders[k] = v
+	return so
+}
+
+// WithContentType adds a content type ("cty") header and returns the updated
+// SignerOptions.
+func (so *SignerOptions) WithContentType(contentType ContentType) *SignerOptions {
+	return so.WithHeader(HeaderContentType, contentType)
+}
+
+// WithType adds a type ("typ") header and returns the updated SignerOptions.
+func (so *SignerOptions) WithType(typ ContentType) *SignerOptions {
+	return so.WithHeader(HeaderType, typ)
+}
+
+type payloadSigner interface {
+	signPayload(payload []byte, alg SignatureAlgorithm) (Signature, error)
+}
+
+type payloadVerifier interface {
+	verifyPayload(payload []byte, signature []byte, alg SignatureAlgorithm) error
+}
+
+type genericSigner struct {
+	recipients   []recipientSigInfo
+	nonceSource  NonceSource
+	embedJWK     bool
+	extraHeaders map[HeaderKey]interface{}
+}
+
+type recipientSigInfo struct {
+	sigAlg    SignatureAlgorithm
+	publicKey *JSONWebKey
+	signer    payloadSigner
+}
+
+// NewSigner creates an appropriate signer based on the key type
+func NewSigner(sig SigningKey, opts *SignerOptions) (Signer, error) {
+	return NewMultiSigner([]SigningKey{sig}, opts)
+}
+
+// NewMultiSigner creates a signer for multiple recipients
+func NewMultiSigner(sigs []SigningKey, opts *SignerOptions) (Signer, error) {
+	signer := &genericSigner{recipients: []recipientSigInfo{}}
+
+	if opts != nil {
+		signer.nonceSource = opts.NonceSource
+		signer.embedJWK = opts.EmbedJWK
+		signer.extraHeaders = opts.ExtraHeaders
+	}
+
+	for _, sig := range sigs {
+		err := signer.addRecipient(sig.Algorithm, sig.Key)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return signer, nil
+}
+
+// newVerifier creates a verifier based on the key type
+func newVerifier(verificationKey interface{}) (payloadVerifier, error) {
+	switch verificationKey := verificationKey.(type) {
+	case ed25519.PublicKey:
+		return &edEncrypterVerifier{
+			publicKey: verificationKey,
+		}, nil
+	case *rsa.PublicKey:
+		return &rsaEncrypterVerifier{
+			publicKey: verificationKey,
+		}, nil
+	case *ecdsa.PublicKey:
+		return &ecEncrypterVerifier{
+			publicKey: verificationKey,
+		}, nil
+	case []byte:
+		return &symmetricMac{
+			key: verificationKey,
+		}, nil
+	case JSONWebKey:
+		return newVerifier(verificationKey.Key)
+	case *JSONWebKey:
+		return newVerifier(verificationKey.Key)
+	default:
+		return nil, ErrUnsupportedKeyType
+	}
+}
+
+func (ctx *genericSigner) addRecipient(alg SignatureAlgorithm, signingKey interface{}) error {
+	recipient, err := makeJWSRecipient(alg, signingKey)
+	if err != nil {
+		return err
+	}
+
+	ctx.recipients = append(ctx.recipients, recipient)
+	return nil
+}
+
+func makeJWSRecipient(alg SignatureAlgorithm, signingKey interface{}) (recipientSigInfo, error) {
+	switch signingKey := signingKey.(type) {
+	case ed25519.PrivateKey:
+		return newEd25519Signer(alg, signingKey)
+	case *rsa.PrivateKey:
+		return newRSASigner(alg, signingKey)
+	case *ecdsa.PrivateKey:
+		return newECDSASigner(alg, signingKey)
+	case []byte:
+		return newSymmetricSigner(alg, signingKey)
+	case JSONWebKey:
+		return newJWKSigner(alg, signingKey)
+	case *JSONWebKey:
+		return newJWKSigner(alg, *signingKey)
+	default:
+		return recipientSigInfo{}, ErrUnsupportedKeyType
+	}
+}
+
+func newJWKSigner(alg SignatureAlgorithm, signingKey JSONWebKey) (recipientSigInfo, error) {
+	recipient, err := makeJWSRecipient(alg, signingKey.Key)
+	if err != nil {
+		return recipientSigInfo{}, err
+	}
+	if recipient.publicKey != nil {
+		// recipient.publicKey is a JWK synthesized for embedding when recipientSigInfo
+		// was created for the inner key (such as a RSA or ECDSA public key). It contains
+		// the pub key for embedding, but doesn't have extra params like key id.
+		publicKey := signingKey
+		publicKey.Key = recipient.publicKey.Key
+		recipient.publicKey = &publicKey
+
+		// This should be impossible, but let's check anyway.
+		if !recipient.publicKey.IsPublic() {
+			return recipientSigInfo{}, errors.New("square/go-jose: public key was unexpectedly not public")
+		}
+	}
+	return recipient, nil
+}
+
+func (ctx *genericSigner) Sign(payload []byte) (*JSONWebSignature, error) {
+	obj := &JSONWebSignature{}
+	obj.payload = payload
+	obj.Signatures = make([]Signature, len(ctx.recipients))
+
+	for i, recipient := range ctx.recipients {
+		protected := map[HeaderKey]interface{}{
+			headerAlgorithm: string(recipient.sigAlg),
+		}
+
+		if recipient.publicKey != nil {
+			// We want to embed the JWK or set the kid header, but not both. Having a protected
+			// header that contains an embedded JWK while also simultaneously containing the kid
+			// header is confusing, and at least in ACME the two are considered to be mutually
+			// exclusive. The fact that both can exist at the same time is a somewhat unfortunate
+			// result of the JOSE spec. We've decided that this library will only include one or
+			// the other to avoid this confusion.
+			//
+			// See https://github.com/square/go-jose/issues/157 for more context.
+			if ctx.embedJWK {
+				protected[headerJWK] = recipient.publicKey
+			} else {
+				protected[headerKeyID] = recipient.publicKey.KeyID
+			}
+		}
+
+		if ctx.nonceSource != nil {
+			nonce, err := ctx.nonceSource.Nonce()
+			if err != nil {
+				return nil, fmt.Errorf("square/go-jose: Error generating nonce: %v", err)
+			}
+			protected[headerNonce] = nonce
+		}
+
+		for k, v := range ctx.extraHeaders {
+			protected[k] = v
+		}
+
+		serializedProtected := mustSerializeJSON(protected)
+
+		input := []byte(fmt.Sprintf("%s.%s",
+			base64.RawURLEncoding.EncodeToString(serializedProtected),
+			base64.RawURLEncoding.EncodeToString(payload)))
+
+		signatureInfo, err := recipient.signer.signPayload(input, recipient.sigAlg)
+		if err != nil {
+			return nil, err
+		}
+
+		signatureInfo.protected = &rawHeader{}
+		for k, v := range protected {
+			b, err := json.Marshal(v)
+			if err != nil {
+				return nil, fmt.Errorf("square/go-jose: Error marshalling item %#v: %v", k, err)
+			}
+			(*signatureInfo.protected)[k] = makeRawMessage(b)
+		}
+		obj.Signatures[i] = signatureInfo
+	}
+
+	return obj, nil
+}
+
+func (ctx *genericSigner) Options() SignerOptions {
+	return SignerOptions{
+		NonceSource:  ctx.nonceSource,
+		EmbedJWK:     ctx.embedJWK,
+		ExtraHeaders: ctx.extraHeaders,
+	}
+}
+
+// Verify validates the signature on the object and returns the payload.
+// This function does not support multi-signature, if you desire multi-sig
+// verification use VerifyMulti instead.
+//
+// Be careful when verifying signatures based on embedded JWKs inside the
+// payload header. You cannot assume that the key received in a payload is
+// trusted.
+func (obj JSONWebSignature) Verify(verificationKey interface{}) ([]byte, error) {
+	verifier, err := newVerifier(verificationKey)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(obj.Signatures) > 1 {
+		return nil, errors.New("square/go-jose: too many signatures in payload; expecting only one")
+	}
+
+	signature := obj.Signatures[0]
+	headers := signature.mergedHeaders()
+	critical, err := headers.getCritical()
+	if err != nil {
+		return nil, err
+	}
+	if len(critical) > 0 {
+		// Unsupported crit header
+		return nil, ErrCryptoFailure
+	}
+
+	input := obj.computeAuthData(&signature)
+	alg := headers.getSignatureAlgorithm()
+	err = verifier.verifyPayload(input, signature.Signature, alg)
+	if err == nil {
+		return obj.payload, nil
+	}
+
+	return nil, ErrCryptoFailure
+}
+
+// VerifyMulti validates (one of the multiple) signatures on the object and
+// returns the index of the signature that was verified, along with the signature
+// object and the payload. We return the signature and index to guarantee that
+// callers are getting the verified value.
+func (obj JSONWebSignature) VerifyMulti(verificationKey interface{}) (int, Signature, []byte, error) {
+	verifier, err := newVerifier(verificationKey)
+	if err != nil {
+		return -1, Signature{}, nil, err
+	}
+
+	for i, signature := range obj.Signatures {
+		headers := signature.mergedHeaders()
+		critical, err := headers.getCritical()
+		if err != nil {
+			continue
+		}
+		if len(critical) > 0 {
+			// Unsupported crit header
+			continue
+		}
+
+		input := obj.computeAuthData(&signature)
+		alg := headers.getSignatureAlgorithm()
+		err = verifier.verifyPayload(input, signature.Signature, alg)
+		if err == nil {
+			return i, signature, obj.payload, nil
+		}
+	}
+
+	return -1, Signature{}, nil, ErrCryptoFailure
+}