1 files changed, 258 insertions, 0 deletions
diff --git a/vendor/github.com/rsc/letsencrypt/vendor/gopkg.in/square/go-jose.v1/signing.go b/vendor/github.com/rsc/letsencrypt/vendor/gopkg.in/square/go-jose.v1/signing.go
new file mode 100644
index 000000000..e64f8ab8d
--- /dev/null
+++ b/vendor/github.com/rsc/letsencrypt/vendor/gopkg.in/square/go-jose.v1/signing.go
@@ -0,0 +1,258 @@
+/*-
+ * 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"
+	"errors"
+	"fmt"
+)
+
+// 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)
+	SetNonceSource(source NonceSource)
+	SetEmbedJwk(embed bool)
+}
+
+// MultiSigner represents a signer which supports multiple recipients.
+type MultiSigner interface {
+	Sign(payload []byte) (*JsonWebSignature, error)
+	SetNonceSource(source NonceSource)
+	SetEmbedJwk(embed bool)
+	AddRecipient(alg SignatureAlgorithm, signingKey interface{}) error
+}
+
+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
+}
+
+type recipientSigInfo struct {
+	sigAlg    SignatureAlgorithm
+	keyID     string
+	publicKey *JsonWebKey
+	signer    payloadSigner
+}
+
+// NewSigner creates an appropriate signer based on the key type
+func NewSigner(alg SignatureAlgorithm, signingKey interface{}) (Signer, error) {
+	// NewMultiSigner never fails (currently)
+	signer := NewMultiSigner()
+
+	err := signer.AddRecipient(alg, signingKey)
+	if err != nil {
+		return nil, err
+	}
+
+	return signer, nil
+}
+
+// NewMultiSigner creates a signer for multiple recipients
+func NewMultiSigner() MultiSigner {
+	return &genericSigner{
+		recipients: []recipientSigInfo{},
+		embedJwk:   true,
+	}
+}
+
+// newVerifier creates a verifier based on the key type
+func newVerifier(verificationKey interface{}) (payloadVerifier, error) {
+	switch verificationKey := verificationKey.(type) {
+	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)
+	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 *rsa.PrivateKey:
+		return newRSASigner(alg, signingKey)
+	case *ecdsa.PrivateKey:
+		return newECDSASigner(alg, signingKey)
+	case []byte:
+		return newSymmetricSigner(alg, signingKey)
+	case *JsonWebKey:
+		recipient, err := makeJWSRecipient(alg, signingKey.Key)
+		if err != nil {
+			return recipientSigInfo{}, err
+		}
+		recipient.keyID = signingKey.KeyID
+		return recipient, nil
+	default:
+		return recipientSigInfo{}, ErrUnsupportedKeyType
+	}
+}
+
+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 := &rawHeader{
+			Alg: string(recipient.sigAlg),
+		}
+
+		if recipient.publicKey != nil && ctx.embedJwk {
+			protected.Jwk = recipient.publicKey
+		}
+		if recipient.keyID != "" {
+			protected.Kid = recipient.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.Nonce = nonce
+		}
+
+		serializedProtected := mustSerializeJSON(protected)
+
+		input := []byte(fmt.Sprintf("%s.%s",
+			base64URLEncode(serializedProtected),
+			base64URLEncode(payload)))
+
+		signatureInfo, err := recipient.signer.signPayload(input, recipient.sigAlg)
+		if err != nil {
+			return nil, err
+		}
+
+		signatureInfo.protected = protected
+		obj.Signatures[i] = signatureInfo
+	}
+
+	return obj, nil
+}
+
+// SetNonceSource provides or updates a nonce pool to the first recipients.
+// After this method is called, the signer will consume one nonce per
+// signature, returning an error it is unable to get a nonce.
+func (ctx *genericSigner) SetNonceSource(source NonceSource) {
+	ctx.nonceSource = source
+}
+
+// SetEmbedJwk specifies if the signing key should be embedded in the protected
+// header, if any. It defaults to 'true', though that may change in the future.
+// Note that the use of embedded JWKs in the signature header can be dangerous,
+// as you cannot assume that the key received in a payload is trusted.
+func (ctx *genericSigner) SetEmbedJwk(embed bool) {
+	ctx.embedJwk = embed
+}
+
+// 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()
+	if len(headers.Crit) > 0 {
+		// Unsupported crit header
+		return nil, ErrCryptoFailure
+	}
+
+	input := obj.computeAuthData(&signature)
+	alg := SignatureAlgorithm(headers.Alg)
+	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()
+		if len(headers.Crit) > 0 {
+			// Unsupported crit header
+			continue
+		}
+
+		input := obj.computeAuthData(&signature)
+		alg := SignatureAlgorithm(headers.Alg)
+		err := verifier.verifyPayload(input, signature.Signature, alg)
+		if err == nil {
+			return i, signature, obj.payload, nil
+		}
+	}
+
+	return -1, Signature{}, nil, ErrCryptoFailure
+}