4 files changed, 442 insertions, 0 deletions
diff --git a/vendor/gopkg.in/square/go-jose.v2/cipher/cbc_hmac.go b/vendor/gopkg.in/square/go-jose.v2/cipher/cbc_hmac.go
new file mode 100644
index 000000000..126b85ce2
--- /dev/null
+++ b/vendor/gopkg.in/square/go-jose.v2/cipher/cbc_hmac.go
@@ -0,0 +1,196 @@
+/*-
+ * 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 josecipher
+
+import (
+	"bytes"
+	"crypto/cipher"
+	"crypto/hmac"
+	"crypto/sha256"
+	"crypto/sha512"
+	"crypto/subtle"
+	"encoding/binary"
+	"errors"
+	"hash"
+)
+
+const (
+	nonceBytes = 16
+)
+
+// NewCBCHMAC instantiates a new AEAD based on CBC+HMAC.
+func NewCBCHMAC(key []byte, newBlockCipher func([]byte) (cipher.Block, error)) (cipher.AEAD, error) {
+	keySize := len(key) / 2
+	integrityKey := key[:keySize]
+	encryptionKey := key[keySize:]
+
+	blockCipher, err := newBlockCipher(encryptionKey)
+	if err != nil {
+		return nil, err
+	}
+
+	var hash func() hash.Hash
+	switch keySize {
+	case 16:
+		hash = sha256.New
+	case 24:
+		hash = sha512.New384
+	case 32:
+		hash = sha512.New
+	}
+
+	return &cbcAEAD{
+		hash:         hash,
+		blockCipher:  blockCipher,
+		authtagBytes: keySize,
+		integrityKey: integrityKey,
+	}, nil
+}
+
+// An AEAD based on CBC+HMAC
+type cbcAEAD struct {
+	hash         func() hash.Hash
+	authtagBytes int
+	integrityKey []byte
+	blockCipher  cipher.Block
+}
+
+func (ctx *cbcAEAD) NonceSize() int {
+	return nonceBytes
+}
+
+func (ctx *cbcAEAD) Overhead() int {
+	// Maximum overhead is block size (for padding) plus auth tag length, where
+	// the length of the auth tag is equivalent to the key size.
+	return ctx.blockCipher.BlockSize() + ctx.authtagBytes
+}
+
+// Seal encrypts and authenticates the plaintext.
+func (ctx *cbcAEAD) Seal(dst, nonce, plaintext, data []byte) []byte {
+	// Output buffer -- must take care not to mangle plaintext input.
+	ciphertext := make([]byte, uint64(len(plaintext))+uint64(ctx.Overhead()))[:len(plaintext)]
+	copy(ciphertext, plaintext)
+	ciphertext = padBuffer(ciphertext, ctx.blockCipher.BlockSize())
+
+	cbc := cipher.NewCBCEncrypter(ctx.blockCipher, nonce)
+
+	cbc.CryptBlocks(ciphertext, ciphertext)
+	authtag := ctx.computeAuthTag(data, nonce, ciphertext)
+
+	ret, out := resize(dst, uint64(len(dst))+uint64(len(ciphertext))+uint64(len(authtag)))
+	copy(out, ciphertext)
+	copy(out[len(ciphertext):], authtag)
+
+	return ret
+}
+
+// Open decrypts and authenticates the ciphertext.
+func (ctx *cbcAEAD) Open(dst, nonce, ciphertext, data []byte) ([]byte, error) {
+	if len(ciphertext) < ctx.authtagBytes {
+		return nil, errors.New("square/go-jose: invalid ciphertext (too short)")
+	}
+
+	offset := len(ciphertext) - ctx.authtagBytes
+	expectedTag := ctx.computeAuthTag(data, nonce, ciphertext[:offset])
+	match := subtle.ConstantTimeCompare(expectedTag, ciphertext[offset:])
+	if match != 1 {
+		return nil, errors.New("square/go-jose: invalid ciphertext (auth tag mismatch)")
+	}
+
+	cbc := cipher.NewCBCDecrypter(ctx.blockCipher, nonce)
+
+	// Make copy of ciphertext buffer, don't want to modify in place
+	buffer := append([]byte{}, []byte(ciphertext[:offset])...)
+
+	if len(buffer)%ctx.blockCipher.BlockSize() > 0 {
+		return nil, errors.New("square/go-jose: invalid ciphertext (invalid length)")
+	}
+
+	cbc.CryptBlocks(buffer, buffer)
+
+	// Remove padding
+	plaintext, err := unpadBuffer(buffer, ctx.blockCipher.BlockSize())
+	if err != nil {
+		return nil, err
+	}
+
+	ret, out := resize(dst, uint64(len(dst))+uint64(len(plaintext)))
+	copy(out, plaintext)
+
+	return ret, nil
+}
+
+// Compute an authentication tag
+func (ctx *cbcAEAD) computeAuthTag(aad, nonce, ciphertext []byte) []byte {
+	buffer := make([]byte, uint64(len(aad))+uint64(len(nonce))+uint64(len(ciphertext))+8)
+	n := 0
+	n += copy(buffer, aad)
+	n += copy(buffer[n:], nonce)
+	n += copy(buffer[n:], ciphertext)
+	binary.BigEndian.PutUint64(buffer[n:], uint64(len(aad))*8)
+
+	// According to documentation, Write() on hash.Hash never fails.
+	hmac := hmac.New(ctx.hash, ctx.integrityKey)
+	_, _ = hmac.Write(buffer)
+
+	return hmac.Sum(nil)[:ctx.authtagBytes]
+}
+
+// resize ensures the the given slice has a capacity of at least n bytes.
+// If the capacity of the slice is less than n, a new slice is allocated
+// and the existing data will be copied.
+func resize(in []byte, n uint64) (head, tail []byte) {
+	if uint64(cap(in)) >= n {
+		head = in[:n]
+	} else {
+		head = make([]byte, n)
+		copy(head, in)
+	}
+
+	tail = head[len(in):]
+	return
+}
+
+// Apply padding
+func padBuffer(buffer []byte, blockSize int) []byte {
+	missing := blockSize - (len(buffer) % blockSize)
+	ret, out := resize(buffer, uint64(len(buffer))+uint64(missing))
+	padding := bytes.Repeat([]byte{byte(missing)}, missing)
+	copy(out, padding)
+	return ret
+}
+
+// Remove padding
+func unpadBuffer(buffer []byte, blockSize int) ([]byte, error) {
+	if len(buffer)%blockSize != 0 {
+		return nil, errors.New("square/go-jose: invalid padding")
+	}
+
+	last := buffer[len(buffer)-1]
+	count := int(last)
+
+	if count == 0 || count > blockSize || count > len(buffer) {
+		return nil, errors.New("square/go-jose: invalid padding")
+	}
+
+	padding := bytes.Repeat([]byte{last}, count)
+	if !bytes.HasSuffix(buffer, padding) {
+		return nil, errors.New("square/go-jose: invalid padding")
+	}
+
+	return buffer[:len(buffer)-count], nil
+}
diff --git a/vendor/gopkg.in/square/go-jose.v2/cipher/concat_kdf.go b/vendor/gopkg.in/square/go-jose.v2/cipher/concat_kdf.go
new file mode 100644
index 000000000..f62c3bdba
--- /dev/null
+++ b/vendor/gopkg.in/square/go-jose.v2/cipher/concat_kdf.go
@@ -0,0 +1,75 @@
+/*-
+ * 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 josecipher
+
+import (
+	"crypto"
+	"encoding/binary"
+	"hash"
+	"io"
+)
+
+type concatKDF struct {
+	z, info []byte
+	i       uint32
+	cache   []byte
+	hasher  hash.Hash
+}
+
+// NewConcatKDF builds a KDF reader based on the given inputs.
+func NewConcatKDF(hash crypto.Hash, z, algID, ptyUInfo, ptyVInfo, supPubInfo, supPrivInfo []byte) io.Reader {
+	buffer := make([]byte, uint64(len(algID))+uint64(len(ptyUInfo))+uint64(len(ptyVInfo))+uint64(len(supPubInfo))+uint64(len(supPrivInfo)))
+	n := 0
+	n += copy(buffer, algID)
+	n += copy(buffer[n:], ptyUInfo)
+	n += copy(buffer[n:], ptyVInfo)
+	n += copy(buffer[n:], supPubInfo)
+	copy(buffer[n:], supPrivInfo)
+
+	hasher := hash.New()
+
+	return &concatKDF{
+		z:      z,
+		info:   buffer,
+		hasher: hasher,
+		cache:  []byte{},
+		i:      1,
+	}
+}
+
+func (ctx *concatKDF) Read(out []byte) (int, error) {
+	copied := copy(out, ctx.cache)
+	ctx.cache = ctx.cache[copied:]
+
+	for copied < len(out) {
+		ctx.hasher.Reset()
+
+		// Write on a hash.Hash never fails
+		_ = binary.Write(ctx.hasher, binary.BigEndian, ctx.i)
+		_, _ = ctx.hasher.Write(ctx.z)
+		_, _ = ctx.hasher.Write(ctx.info)
+
+		hash := ctx.hasher.Sum(nil)
+		chunkCopied := copy(out[copied:], hash)
+		copied += chunkCopied
+		ctx.cache = hash[chunkCopied:]
+
+		ctx.i++
+	}
+
+	return copied, nil
+}
diff --git a/vendor/gopkg.in/square/go-jose.v2/cipher/ecdh_es.go b/vendor/gopkg.in/square/go-jose.v2/cipher/ecdh_es.go
new file mode 100644
index 000000000..c128e327f
--- /dev/null
+++ b/vendor/gopkg.in/square/go-jose.v2/cipher/ecdh_es.go
@@ -0,0 +1,62 @@
+/*-
+ * 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 josecipher
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"encoding/binary"
+)
+
+// DeriveECDHES derives a shared encryption key using ECDH/ConcatKDF as described in JWE/JWA.
+// It is an error to call this function with a private/public key that are not on the same
+// curve. Callers must ensure that the keys are valid before calling this function. Output
+// size may be at most 1<<16 bytes (64 KiB).
+func DeriveECDHES(alg string, apuData, apvData []byte, priv *ecdsa.PrivateKey, pub *ecdsa.PublicKey, size int) []byte {
+	if size > 1<<16 {
+		panic("ECDH-ES output size too large, must be less than or equal to 1<<16")
+	}
+
+	// algId, partyUInfo, partyVInfo inputs must be prefixed with the length
+	algID := lengthPrefixed([]byte(alg))
+	ptyUInfo := lengthPrefixed(apuData)
+	ptyVInfo := lengthPrefixed(apvData)
+
+	// suppPubInfo is the encoded length of the output size in bits
+	supPubInfo := make([]byte, 4)
+	binary.BigEndian.PutUint32(supPubInfo, uint32(size)*8)
+
+	if !priv.PublicKey.Curve.IsOnCurve(pub.X, pub.Y) {
+		panic("public key not on same curve as private key")
+	}
+
+	z, _ := priv.PublicKey.Curve.ScalarMult(pub.X, pub.Y, priv.D.Bytes())
+	reader := NewConcatKDF(crypto.SHA256, z.Bytes(), algID, ptyUInfo, ptyVInfo, supPubInfo, []byte{})
+
+	key := make([]byte, size)
+
+	// Read on the KDF will never fail
+	_, _ = reader.Read(key)
+	return key
+}
+
+func lengthPrefixed(data []byte) []byte {
+	out := make([]byte, len(data)+4)
+	binary.BigEndian.PutUint32(out, uint32(len(data)))
+	copy(out[4:], data)
+	return out
+}
diff --git a/vendor/gopkg.in/square/go-jose.v2/cipher/key_wrap.go b/vendor/gopkg.in/square/go-jose.v2/cipher/key_wrap.go
new file mode 100644
index 000000000..1d36d5015
--- /dev/null
+++ b/vendor/gopkg.in/square/go-jose.v2/cipher/key_wrap.go
@@ -0,0 +1,109 @@
+/*-
+ * 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 josecipher
+
+import (
+	"crypto/cipher"
+	"crypto/subtle"
+	"encoding/binary"
+	"errors"
+)
+
+var defaultIV = []byte{0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6}
+
+// KeyWrap implements NIST key wrapping; it wraps a content encryption key (cek) with the given block cipher.
+func KeyWrap(block cipher.Block, cek []byte) ([]byte, error) {
+	if len(cek)%8 != 0 {
+		return nil, errors.New("square/go-jose: key wrap input must be 8 byte blocks")
+	}
+
+	n := len(cek) / 8
+	r := make([][]byte, n)
+
+	for i := range r {
+		r[i] = make([]byte, 8)
+		copy(r[i], cek[i*8:])
+	}
+
+	buffer := make([]byte, 16)
+	tBytes := make([]byte, 8)
+	copy(buffer, defaultIV)
+
+	for t := 0; t < 6*n; t++ {
+		copy(buffer[8:], r[t%n])
+
+		block.Encrypt(buffer, buffer)
+
+		binary.BigEndian.PutUint64(tBytes, uint64(t+1))
+
+		for i := 0; i < 8; i++ {
+			buffer[i] = buffer[i] ^ tBytes[i]
+		}
+		copy(r[t%n], buffer[8:])
+	}
+
+	out := make([]byte, (n+1)*8)
+	copy(out, buffer[:8])
+	for i := range r {
+		copy(out[(i+1)*8:], r[i])
+	}
+
+	return out, nil
+}
+
+// KeyUnwrap implements NIST key unwrapping; it unwraps a content encryption key (cek) with the given block cipher.
+func KeyUnwrap(block cipher.Block, ciphertext []byte) ([]byte, error) {
+	if len(ciphertext)%8 != 0 {
+		return nil, errors.New("square/go-jose: key wrap input must be 8 byte blocks")
+	}
+
+	n := (len(ciphertext) / 8) - 1
+	r := make([][]byte, n)
+
+	for i := range r {
+		r[i] = make([]byte, 8)
+		copy(r[i], ciphertext[(i+1)*8:])
+	}
+
+	buffer := make([]byte, 16)
+	tBytes := make([]byte, 8)
+	copy(buffer[:8], ciphertext[:8])
+
+	for t := 6*n - 1; t >= 0; t-- {
+		binary.BigEndian.PutUint64(tBytes, uint64(t+1))
+
+		for i := 0; i < 8; i++ {
+			buffer[i] = buffer[i] ^ tBytes[i]
+		}
+		copy(buffer[8:], r[t%n])
+
+		block.Decrypt(buffer, buffer)
+
+		copy(r[t%n], buffer[8:])
+	}
+
+	if subtle.ConstantTimeCompare(buffer[:8], defaultIV) == 0 {
+		return nil, errors.New("square/go-jose: failed to unwrap key")
+	}
+
+	out := make([]byte, n*8)
+	for i := range r {
+		copy(out[i*8:], r[i])
+	}
+
+	return out, nil
+}