1 files changed, 520 insertions, 0 deletions
diff --git a/vendor/github.com/rsc/letsencrypt/vendor/gopkg.in/square/go-jose.v1/asymmetric.go b/vendor/github.com/rsc/letsencrypt/vendor/gopkg.in/square/go-jose.v1/asymmetric.go
new file mode 100644
index 000000000..cd36c21da
--- /dev/null
+++ b/vendor/github.com/rsc/letsencrypt/vendor/gopkg.in/square/go-jose.v1/asymmetric.go
@@ -0,0 +1,520 @@
+/*-
+ * 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"
+	"crypto/aes"
+	"crypto/ecdsa"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha1"
+	"crypto/sha256"
+	"errors"
+	"fmt"
+	"math/big"
+
+	"gopkg.in/square/go-jose.v1/cipher"
+)
+
+// A generic RSA-based encrypter/verifier
+type rsaEncrypterVerifier struct {
+	publicKey *rsa.PublicKey
+}
+
+// A generic RSA-based decrypter/signer
+type rsaDecrypterSigner struct {
+	privateKey *rsa.PrivateKey
+}
+
+// A generic EC-based encrypter/verifier
+type ecEncrypterVerifier struct {
+	publicKey *ecdsa.PublicKey
+}
+
+// A key generator for ECDH-ES
+type ecKeyGenerator struct {
+	size      int
+	algID     string
+	publicKey *ecdsa.PublicKey
+}
+
+// A generic EC-based decrypter/signer
+type ecDecrypterSigner struct {
+	privateKey *ecdsa.PrivateKey
+}
+
+// newRSARecipient creates recipientKeyInfo based on the given key.
+func newRSARecipient(keyAlg KeyAlgorithm, publicKey *rsa.PublicKey) (recipientKeyInfo, error) {
+	// Verify that key management algorithm is supported by this encrypter
+	switch keyAlg {
+	case RSA1_5, RSA_OAEP, RSA_OAEP_256:
+	default:
+		return recipientKeyInfo{}, ErrUnsupportedAlgorithm
+	}
+
+	if publicKey == nil {
+		return recipientKeyInfo{}, errors.New("invalid public key")
+	}
+
+	return recipientKeyInfo{
+		keyAlg: keyAlg,
+		keyEncrypter: &rsaEncrypterVerifier{
+			publicKey: publicKey,
+		},
+	}, nil
+}
+
+// newRSASigner creates a recipientSigInfo based on the given key.
+func newRSASigner(sigAlg SignatureAlgorithm, privateKey *rsa.PrivateKey) (recipientSigInfo, error) {
+	// Verify that key management algorithm is supported by this encrypter
+	switch sigAlg {
+	case RS256, RS384, RS512, PS256, PS384, PS512:
+	default:
+		return recipientSigInfo{}, ErrUnsupportedAlgorithm
+	}
+
+	if privateKey == nil {
+		return recipientSigInfo{}, errors.New("invalid private key")
+	}
+
+	return recipientSigInfo{
+		sigAlg: sigAlg,
+		publicKey: &JsonWebKey{
+			Key: &privateKey.PublicKey,
+		},
+		signer: &rsaDecrypterSigner{
+			privateKey: privateKey,
+		},
+	}, nil
+}
+
+// newECDHRecipient creates recipientKeyInfo based on the given key.
+func newECDHRecipient(keyAlg KeyAlgorithm, publicKey *ecdsa.PublicKey) (recipientKeyInfo, error) {
+	// Verify that key management algorithm is supported by this encrypter
+	switch keyAlg {
+	case ECDH_ES, ECDH_ES_A128KW, ECDH_ES_A192KW, ECDH_ES_A256KW:
+	default:
+		return recipientKeyInfo{}, ErrUnsupportedAlgorithm
+	}
+
+	if publicKey == nil || !publicKey.Curve.IsOnCurve(publicKey.X, publicKey.Y) {
+		return recipientKeyInfo{}, errors.New("invalid public key")
+	}
+
+	return recipientKeyInfo{
+		keyAlg: keyAlg,
+		keyEncrypter: &ecEncrypterVerifier{
+			publicKey: publicKey,
+		},
+	}, nil
+}
+
+// newECDSASigner creates a recipientSigInfo based on the given key.
+func newECDSASigner(sigAlg SignatureAlgorithm, privateKey *ecdsa.PrivateKey) (recipientSigInfo, error) {
+	// Verify that key management algorithm is supported by this encrypter
+	switch sigAlg {
+	case ES256, ES384, ES512:
+	default:
+		return recipientSigInfo{}, ErrUnsupportedAlgorithm
+	}
+
+	if privateKey == nil {
+		return recipientSigInfo{}, errors.New("invalid private key")
+	}
+
+	return recipientSigInfo{
+		sigAlg: sigAlg,
+		publicKey: &JsonWebKey{
+			Key: &privateKey.PublicKey,
+		},
+		signer: &ecDecrypterSigner{
+			privateKey: privateKey,
+		},
+	}, nil
+}
+
+// Encrypt the given payload and update the object.
+func (ctx rsaEncrypterVerifier) encryptKey(cek []byte, alg KeyAlgorithm) (recipientInfo, error) {
+	encryptedKey, err := ctx.encrypt(cek, alg)
+	if err != nil {
+		return recipientInfo{}, err
+	}
+
+	return recipientInfo{
+		encryptedKey: encryptedKey,
+		header:       &rawHeader{},
+	}, nil
+}
+
+// Encrypt the given payload. Based on the key encryption algorithm,
+// this will either use RSA-PKCS1v1.5 or RSA-OAEP (with SHA-1 or SHA-256).
+func (ctx rsaEncrypterVerifier) encrypt(cek []byte, alg KeyAlgorithm) ([]byte, error) {
+	switch alg {
+	case RSA1_5:
+		return rsa.EncryptPKCS1v15(randReader, ctx.publicKey, cek)
+	case RSA_OAEP:
+		return rsa.EncryptOAEP(sha1.New(), randReader, ctx.publicKey, cek, []byte{})
+	case RSA_OAEP_256:
+		return rsa.EncryptOAEP(sha256.New(), randReader, ctx.publicKey, cek, []byte{})
+	}
+
+	return nil, ErrUnsupportedAlgorithm
+}
+
+// Decrypt the given payload and return the content encryption key.
+func (ctx rsaDecrypterSigner) decryptKey(headers rawHeader, recipient *recipientInfo, generator keyGenerator) ([]byte, error) {
+	return ctx.decrypt(recipient.encryptedKey, KeyAlgorithm(headers.Alg), generator)
+}
+
+// Decrypt the given payload. Based on the key encryption algorithm,
+// this will either use RSA-PKCS1v1.5 or RSA-OAEP (with SHA-1 or SHA-256).
+func (ctx rsaDecrypterSigner) decrypt(jek []byte, alg KeyAlgorithm, generator keyGenerator) ([]byte, error) {
+	// Note: The random reader on decrypt operations is only used for blinding,
+	// so stubbing is meanlingless (hence the direct use of rand.Reader).
+	switch alg {
+	case RSA1_5:
+		defer func() {
+			// DecryptPKCS1v15SessionKey sometimes panics on an invalid payload
+			// because of an index out of bounds error, which we want to ignore.
+			// This has been fixed in Go 1.3.1 (released 2014/08/13), the recover()
+			// only exists for preventing crashes with unpatched versions.
+			// See: https://groups.google.com/forum/#!topic/golang-dev/7ihX6Y6kx9k
+			// See: https://code.google.com/p/go/source/detail?r=58ee390ff31602edb66af41ed10901ec95904d33
+			_ = recover()
+		}()
+
+		// Perform some input validation.
+		keyBytes := ctx.privateKey.PublicKey.N.BitLen() / 8
+		if keyBytes != len(jek) {
+			// Input size is incorrect, the encrypted payload should always match
+			// the size of the public modulus (e.g. using a 2048 bit key will
+			// produce 256 bytes of output). Reject this since it's invalid input.
+			return nil, ErrCryptoFailure
+		}
+
+		cek, _, err := generator.genKey()
+		if err != nil {
+			return nil, ErrCryptoFailure
+		}
+
+		// When decrypting an RSA-PKCS1v1.5 payload, we must take precautions to
+		// prevent chosen-ciphertext attacks as described in RFC 3218, "Preventing
+		// the Million Message Attack on Cryptographic Message Syntax". We are
+		// therefore deliberately ignoring errors here.
+		_ = rsa.DecryptPKCS1v15SessionKey(rand.Reader, ctx.privateKey, jek, cek)
+
+		return cek, nil
+	case RSA_OAEP:
+		// Use rand.Reader for RSA blinding
+		return rsa.DecryptOAEP(sha1.New(), rand.Reader, ctx.privateKey, jek, []byte{})
+	case RSA_OAEP_256:
+		// Use rand.Reader for RSA blinding
+		return rsa.DecryptOAEP(sha256.New(), rand.Reader, ctx.privateKey, jek, []byte{})
+	}
+
+	return nil, ErrUnsupportedAlgorithm
+}
+
+// Sign the given payload
+func (ctx rsaDecrypterSigner) signPayload(payload []byte, alg SignatureAlgorithm) (Signature, error) {
+	var hash crypto.Hash
+
+	switch alg {
+	case RS256, PS256:
+		hash = crypto.SHA256
+	case RS384, PS384:
+		hash = crypto.SHA384
+	case RS512, PS512:
+		hash = crypto.SHA512
+	default:
+		return Signature{}, ErrUnsupportedAlgorithm
+	}
+
+	hasher := hash.New()
+
+	// According to documentation, Write() on hash never fails
+	_, _ = hasher.Write(payload)
+	hashed := hasher.Sum(nil)
+
+	var out []byte
+	var err error
+
+	switch alg {
+	case RS256, RS384, RS512:
+		out, err = rsa.SignPKCS1v15(randReader, ctx.privateKey, hash, hashed)
+	case PS256, PS384, PS512:
+		out, err = rsa.SignPSS(randReader, ctx.privateKey, hash, hashed, &rsa.PSSOptions{
+			SaltLength: rsa.PSSSaltLengthAuto,
+		})
+	}
+
+	if err != nil {
+		return Signature{}, err
+	}
+
+	return Signature{
+		Signature: out,
+		protected: &rawHeader{},
+	}, nil
+}
+
+// Verify the given payload
+func (ctx rsaEncrypterVerifier) verifyPayload(payload []byte, signature []byte, alg SignatureAlgorithm) error {
+	var hash crypto.Hash
+
+	switch alg {
+	case RS256, PS256:
+		hash = crypto.SHA256
+	case RS384, PS384:
+		hash = crypto.SHA384
+	case RS512, PS512:
+		hash = crypto.SHA512
+	default:
+		return ErrUnsupportedAlgorithm
+	}
+
+	hasher := hash.New()
+
+	// According to documentation, Write() on hash never fails
+	_, _ = hasher.Write(payload)
+	hashed := hasher.Sum(nil)
+
+	switch alg {
+	case RS256, RS384, RS512:
+		return rsa.VerifyPKCS1v15(ctx.publicKey, hash, hashed, signature)
+	case PS256, PS384, PS512:
+		return rsa.VerifyPSS(ctx.publicKey, hash, hashed, signature, nil)
+	}
+
+	return ErrUnsupportedAlgorithm
+}
+
+// Encrypt the given payload and update the object.
+func (ctx ecEncrypterVerifier) encryptKey(cek []byte, alg KeyAlgorithm) (recipientInfo, error) {
+	switch alg {
+	case ECDH_ES:
+		// ECDH-ES mode doesn't wrap a key, the shared secret is used directly as the key.
+		return recipientInfo{
+			header: &rawHeader{},
+		}, nil
+	case ECDH_ES_A128KW, ECDH_ES_A192KW, ECDH_ES_A256KW:
+	default:
+		return recipientInfo{}, ErrUnsupportedAlgorithm
+	}
+
+	generator := ecKeyGenerator{
+		algID:     string(alg),
+		publicKey: ctx.publicKey,
+	}
+
+	switch alg {
+	case ECDH_ES_A128KW:
+		generator.size = 16
+	case ECDH_ES_A192KW:
+		generator.size = 24
+	case ECDH_ES_A256KW:
+		generator.size = 32
+	}
+
+	kek, header, err := generator.genKey()
+	if err != nil {
+		return recipientInfo{}, err
+	}
+
+	block, err := aes.NewCipher(kek)
+	if err != nil {
+		return recipientInfo{}, err
+	}
+
+	jek, err := josecipher.KeyWrap(block, cek)
+	if err != nil {
+		return recipientInfo{}, err
+	}
+
+	return recipientInfo{
+		encryptedKey: jek,
+		header:       &header,
+	}, nil
+}
+
+// Get key size for EC key generator
+func (ctx ecKeyGenerator) keySize() int {
+	return ctx.size
+}
+
+// Get a content encryption key for ECDH-ES
+func (ctx ecKeyGenerator) genKey() ([]byte, rawHeader, error) {
+	priv, err := ecdsa.GenerateKey(ctx.publicKey.Curve, randReader)
+	if err != nil {
+		return nil, rawHeader{}, err
+	}
+
+	out := josecipher.DeriveECDHES(ctx.algID, []byte{}, []byte{}, priv, ctx.publicKey, ctx.size)
+
+	headers := rawHeader{
+		Epk: &JsonWebKey{
+			Key: &priv.PublicKey,
+		},
+	}
+
+	return out, headers, nil
+}
+
+// Decrypt the given payload and return the content encryption key.
+func (ctx ecDecrypterSigner) decryptKey(headers rawHeader, recipient *recipientInfo, generator keyGenerator) ([]byte, error) {
+	if headers.Epk == nil {
+		return nil, errors.New("square/go-jose: missing epk header")
+	}
+
+	publicKey, ok := headers.Epk.Key.(*ecdsa.PublicKey)
+	if publicKey == nil || !ok {
+		return nil, errors.New("square/go-jose: invalid epk header")
+	}
+
+	if !ctx.privateKey.Curve.IsOnCurve(publicKey.X, publicKey.Y) {
+		return nil, errors.New("square/go-jose: invalid public key in epk header")
+	}
+
+	apuData := headers.Apu.bytes()
+	apvData := headers.Apv.bytes()
+
+	deriveKey := func(algID string, size int) []byte {
+		return josecipher.DeriveECDHES(algID, apuData, apvData, ctx.privateKey, publicKey, size)
+	}
+
+	var keySize int
+
+	switch KeyAlgorithm(headers.Alg) {
+	case ECDH_ES:
+		// ECDH-ES uses direct key agreement, no key unwrapping necessary.
+		return deriveKey(string(headers.Enc), generator.keySize()), nil
+	case ECDH_ES_A128KW:
+		keySize = 16
+	case ECDH_ES_A192KW:
+		keySize = 24
+	case ECDH_ES_A256KW:
+		keySize = 32
+	default:
+		return nil, ErrUnsupportedAlgorithm
+	}
+
+	key := deriveKey(headers.Alg, keySize)
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	return josecipher.KeyUnwrap(block, recipient.encryptedKey)
+}
+
+// Sign the given payload
+func (ctx ecDecrypterSigner) signPayload(payload []byte, alg SignatureAlgorithm) (Signature, error) {
+	var expectedBitSize int
+	var hash crypto.Hash
+
+	switch alg {
+	case ES256:
+		expectedBitSize = 256
+		hash = crypto.SHA256
+	case ES384:
+		expectedBitSize = 384
+		hash = crypto.SHA384
+	case ES512:
+		expectedBitSize = 521
+		hash = crypto.SHA512
+	}
+
+	curveBits := ctx.privateKey.Curve.Params().BitSize
+	if expectedBitSize != curveBits {
+		return Signature{}, fmt.Errorf("square/go-jose: expected %d bit key, got %d bits instead", expectedBitSize, curveBits)
+	}
+
+	hasher := hash.New()
+
+	// According to documentation, Write() on hash never fails
+	_, _ = hasher.Write(payload)
+	hashed := hasher.Sum(nil)
+
+	r, s, err := ecdsa.Sign(randReader, ctx.privateKey, hashed)
+	if err != nil {
+		return Signature{}, err
+	}
+
+	keyBytes := curveBits / 8
+	if curveBits%8 > 0 {
+		keyBytes += 1
+	}
+
+	// We serialize the outpus (r and s) into big-endian byte arrays and pad
+	// them with zeros on the left to make sure the sizes work out. Both arrays
+	// must be keyBytes long, and the output must be 2*keyBytes long.
+	rBytes := r.Bytes()
+	rBytesPadded := make([]byte, keyBytes)
+	copy(rBytesPadded[keyBytes-len(rBytes):], rBytes)
+
+	sBytes := s.Bytes()
+	sBytesPadded := make([]byte, keyBytes)
+	copy(sBytesPadded[keyBytes-len(sBytes):], sBytes)
+
+	out := append(rBytesPadded, sBytesPadded...)
+
+	return Signature{
+		Signature: out,
+		protected: &rawHeader{},
+	}, nil
+}
+
+// Verify the given payload
+func (ctx ecEncrypterVerifier) verifyPayload(payload []byte, signature []byte, alg SignatureAlgorithm) error {
+	var keySize int
+	var hash crypto.Hash
+
+	switch alg {
+	case ES256:
+		keySize = 32
+		hash = crypto.SHA256
+	case ES384:
+		keySize = 48
+		hash = crypto.SHA384
+	case ES512:
+		keySize = 66
+		hash = crypto.SHA512
+	default:
+		return ErrUnsupportedAlgorithm
+	}
+
+	if len(signature) != 2*keySize {
+		return fmt.Errorf("square/go-jose: invalid signature size, have %d bytes, wanted %d", len(signature), 2*keySize)
+	}
+
+	hasher := hash.New()
+
+	// According to documentation, Write() on hash never fails
+	_, _ = hasher.Write(payload)
+	hashed := hasher.Sum(nil)
+
+	r := big.NewInt(0).SetBytes(signature[:keySize])
+	s := big.NewInt(0).SetBytes(signature[keySize:])
+
+	match := ecdsa.Verify(ctx.publicKey, hashed, r, s)
+	if !match {
+		return errors.New("square/go-jose: ecdsa signature failed to verify")
+	}
+
+	return nil
+}