diff options
Diffstat (limited to 'vendor/gopkg.in/square/go-jose.v1/crypter.go')
-rw-r--r-- | vendor/gopkg.in/square/go-jose.v1/crypter.go | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/vendor/gopkg.in/square/go-jose.v1/crypter.go b/vendor/gopkg.in/square/go-jose.v1/crypter.go new file mode 100644 index 000000000..b3bdaec80 --- /dev/null +++ b/vendor/gopkg.in/square/go-jose.v1/crypter.go @@ -0,0 +1,416 @@ +/*- + * 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" + "reflect" +) + +// Encrypter represents an encrypter which produces an encrypted JWE object. +type Encrypter interface { + Encrypt(plaintext []byte) (*JsonWebEncryption, error) + EncryptWithAuthData(plaintext []byte, aad []byte) (*JsonWebEncryption, error) + SetCompression(alg CompressionAlgorithm) +} + +// MultiEncrypter represents an encrypter which supports multiple recipients. +type MultiEncrypter interface { + Encrypt(plaintext []byte) (*JsonWebEncryption, error) + EncryptWithAuthData(plaintext []byte, aad []byte) (*JsonWebEncryption, error) + SetCompression(alg CompressionAlgorithm) + AddRecipient(alg KeyAlgorithm, encryptionKey interface{}) error +} + +// A generic content cipher +type contentCipher interface { + keySize() int + encrypt(cek []byte, aad, plaintext []byte) (*aeadParts, error) + decrypt(cek []byte, aad []byte, parts *aeadParts) ([]byte, error) +} + +// A key generator (for generating/getting a CEK) +type keyGenerator interface { + keySize() int + genKey() ([]byte, rawHeader, error) +} + +// A generic key encrypter +type keyEncrypter interface { + encryptKey(cek []byte, alg KeyAlgorithm) (recipientInfo, error) // Encrypt a key +} + +// A generic key decrypter +type keyDecrypter interface { + decryptKey(headers rawHeader, recipient *recipientInfo, generator keyGenerator) ([]byte, error) // Decrypt a key +} + +// A generic encrypter based on the given key encrypter and content cipher. +type genericEncrypter struct { + contentAlg ContentEncryption + compressionAlg CompressionAlgorithm + cipher contentCipher + recipients []recipientKeyInfo + keyGenerator keyGenerator +} + +type recipientKeyInfo struct { + keyID string + keyAlg KeyAlgorithm + keyEncrypter keyEncrypter +} + +// SetCompression sets a compression algorithm to be applied before encryption. +func (ctx *genericEncrypter) SetCompression(compressionAlg CompressionAlgorithm) { + ctx.compressionAlg = compressionAlg +} + +// NewEncrypter creates an appropriate encrypter based on the key type +func NewEncrypter(alg KeyAlgorithm, enc ContentEncryption, encryptionKey interface{}) (Encrypter, error) { + encrypter := &genericEncrypter{ + contentAlg: enc, + compressionAlg: NONE, + recipients: []recipientKeyInfo{}, + cipher: getContentCipher(enc), + } + + if encrypter.cipher == nil { + return nil, ErrUnsupportedAlgorithm + } + + var keyID string + var rawKey interface{} + switch encryptionKey := encryptionKey.(type) { + case *JsonWebKey: + keyID = encryptionKey.KeyID + rawKey = encryptionKey.Key + default: + rawKey = encryptionKey + } + + switch alg { + case DIRECT: + // Direct encryption mode must be treated differently + if reflect.TypeOf(rawKey) != reflect.TypeOf([]byte{}) { + return nil, ErrUnsupportedKeyType + } + encrypter.keyGenerator = staticKeyGenerator{ + key: rawKey.([]byte), + } + recipient, _ := newSymmetricRecipient(alg, rawKey.([]byte)) + if keyID != "" { + recipient.keyID = keyID + } + encrypter.recipients = []recipientKeyInfo{recipient} + return encrypter, nil + case ECDH_ES: + // ECDH-ES (w/o key wrapping) is similar to DIRECT mode + typeOf := reflect.TypeOf(rawKey) + if typeOf != reflect.TypeOf(&ecdsa.PublicKey{}) { + return nil, ErrUnsupportedKeyType + } + encrypter.keyGenerator = ecKeyGenerator{ + size: encrypter.cipher.keySize(), + algID: string(enc), + publicKey: rawKey.(*ecdsa.PublicKey), + } + recipient, _ := newECDHRecipient(alg, rawKey.(*ecdsa.PublicKey)) + if keyID != "" { + recipient.keyID = keyID + } + encrypter.recipients = []recipientKeyInfo{recipient} + return encrypter, nil + default: + // Can just add a standard recipient + encrypter.keyGenerator = randomKeyGenerator{ + size: encrypter.cipher.keySize(), + } + err := encrypter.AddRecipient(alg, encryptionKey) + return encrypter, err + } +} + +// NewMultiEncrypter creates a multi-encrypter based on the given parameters +func NewMultiEncrypter(enc ContentEncryption) (MultiEncrypter, error) { + cipher := getContentCipher(enc) + + if cipher == nil { + return nil, ErrUnsupportedAlgorithm + } + + encrypter := &genericEncrypter{ + contentAlg: enc, + compressionAlg: NONE, + recipients: []recipientKeyInfo{}, + cipher: cipher, + keyGenerator: randomKeyGenerator{ + size: cipher.keySize(), + }, + } + + return encrypter, nil +} + +func (ctx *genericEncrypter) AddRecipient(alg KeyAlgorithm, encryptionKey interface{}) (err error) { + var recipient recipientKeyInfo + + switch alg { + case DIRECT, ECDH_ES: + return fmt.Errorf("square/go-jose: key algorithm '%s' not supported in multi-recipient mode", alg) + } + + recipient, err = makeJWERecipient(alg, encryptionKey) + + if err == nil { + ctx.recipients = append(ctx.recipients, recipient) + } + return err +} + +func makeJWERecipient(alg KeyAlgorithm, encryptionKey interface{}) (recipientKeyInfo, error) { + switch encryptionKey := encryptionKey.(type) { + case *rsa.PublicKey: + return newRSARecipient(alg, encryptionKey) + case *ecdsa.PublicKey: + return newECDHRecipient(alg, encryptionKey) + case []byte: + return newSymmetricRecipient(alg, encryptionKey) + case *JsonWebKey: + recipient, err := makeJWERecipient(alg, encryptionKey.Key) + if err == nil && encryptionKey.KeyID != "" { + recipient.keyID = encryptionKey.KeyID + } + return recipient, err + default: + return recipientKeyInfo{}, ErrUnsupportedKeyType + } +} + +// newDecrypter creates an appropriate decrypter based on the key type +func newDecrypter(decryptionKey interface{}) (keyDecrypter, error) { + switch decryptionKey := decryptionKey.(type) { + case *rsa.PrivateKey: + return &rsaDecrypterSigner{ + privateKey: decryptionKey, + }, nil + case *ecdsa.PrivateKey: + return &ecDecrypterSigner{ + privateKey: decryptionKey, + }, nil + case []byte: + return &symmetricKeyCipher{ + key: decryptionKey, + }, nil + case *JsonWebKey: + return newDecrypter(decryptionKey.Key) + default: + return nil, ErrUnsupportedKeyType + } +} + +// Implementation of encrypt method producing a JWE object. +func (ctx *genericEncrypter) Encrypt(plaintext []byte) (*JsonWebEncryption, error) { + return ctx.EncryptWithAuthData(plaintext, nil) +} + +// Implementation of encrypt method producing a JWE object. +func (ctx *genericEncrypter) EncryptWithAuthData(plaintext, aad []byte) (*JsonWebEncryption, error) { + obj := &JsonWebEncryption{} + obj.aad = aad + + obj.protected = &rawHeader{ + Enc: ctx.contentAlg, + } + obj.recipients = make([]recipientInfo, len(ctx.recipients)) + + if len(ctx.recipients) == 0 { + return nil, fmt.Errorf("square/go-jose: no recipients to encrypt to") + } + + cek, headers, err := ctx.keyGenerator.genKey() + if err != nil { + return nil, err + } + + obj.protected.merge(&headers) + + for i, info := range ctx.recipients { + recipient, err := info.keyEncrypter.encryptKey(cek, info.keyAlg) + if err != nil { + return nil, err + } + + recipient.header.Alg = string(info.keyAlg) + if info.keyID != "" { + recipient.header.Kid = info.keyID + } + obj.recipients[i] = recipient + } + + if len(ctx.recipients) == 1 { + // Move per-recipient headers into main protected header if there's + // only a single recipient. + obj.protected.merge(obj.recipients[0].header) + obj.recipients[0].header = nil + } + + if ctx.compressionAlg != NONE { + plaintext, err = compress(ctx.compressionAlg, plaintext) + if err != nil { + return nil, err + } + + obj.protected.Zip = ctx.compressionAlg + } + + authData := obj.computeAuthData() + parts, err := ctx.cipher.encrypt(cek, authData, plaintext) + if err != nil { + return nil, err + } + + obj.iv = parts.iv + obj.ciphertext = parts.ciphertext + obj.tag = parts.tag + + return obj, nil +} + +// 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. +func (obj JsonWebEncryption) Decrypt(decryptionKey interface{}) ([]byte, error) { + headers := obj.mergedHeaders(nil) + + if len(obj.recipients) > 1 { + return nil, errors.New("square/go-jose: too many recipients in payload; expecting only one") + } + + if len(headers.Crit) > 0 { + return nil, fmt.Errorf("square/go-jose: unsupported crit header") + } + + decrypter, err := newDecrypter(decryptionKey) + if err != nil { + return nil, err + } + + cipher := getContentCipher(headers.Enc) + if cipher == nil { + return nil, fmt.Errorf("square/go-jose: unsupported enc value '%s'", string(headers.Enc)) + } + + generator := randomKeyGenerator{ + size: cipher.keySize(), + } + + parts := &aeadParts{ + iv: obj.iv, + ciphertext: obj.ciphertext, + tag: obj.tag, + } + + authData := obj.computeAuthData() + + var plaintext []byte + recipient := obj.recipients[0] + recipientHeaders := obj.mergedHeaders(&recipient) + + cek, err := decrypter.decryptKey(recipientHeaders, &recipient, generator) + if err == nil { + // Found a valid CEK -- let's try to decrypt. + plaintext, err = cipher.decrypt(cek, authData, parts) + } + + if plaintext == nil { + return nil, ErrCryptoFailure + } + + // The "zip" header parameter may only be present in the protected header. + if obj.protected.Zip != "" { + plaintext, err = decompress(obj.protected.Zip, plaintext) + } + + return plaintext, err +} + +// DecryptMulti decrypts and validates the object and returns the plaintexts, +// with support for multiple recipients. It returns the index of the recipient +// for which the decryption was successful, the merged headers for that recipient, +// and the plaintext. +func (obj JsonWebEncryption) DecryptMulti(decryptionKey interface{}) (int, JoseHeader, []byte, error) { + globalHeaders := obj.mergedHeaders(nil) + + if len(globalHeaders.Crit) > 0 { + return -1, JoseHeader{}, nil, fmt.Errorf("square/go-jose: unsupported crit header") + } + + decrypter, err := newDecrypter(decryptionKey) + if err != nil { + return -1, JoseHeader{}, nil, err + } + + cipher := getContentCipher(globalHeaders.Enc) + if cipher == nil { + return -1, JoseHeader{}, nil, fmt.Errorf("square/go-jose: unsupported enc value '%s'", string(globalHeaders.Enc)) + } + + generator := randomKeyGenerator{ + size: cipher.keySize(), + } + + parts := &aeadParts{ + iv: obj.iv, + ciphertext: obj.ciphertext, + tag: obj.tag, + } + + authData := obj.computeAuthData() + + index := -1 + var plaintext []byte + var headers rawHeader + + for i, recipient := range obj.recipients { + recipientHeaders := obj.mergedHeaders(&recipient) + + cek, err := decrypter.decryptKey(recipientHeaders, &recipient, generator) + if err == nil { + // Found a valid CEK -- let's try to decrypt. + plaintext, err = cipher.decrypt(cek, authData, parts) + if err == nil { + index = i + headers = recipientHeaders + break + } + } + } + + if plaintext == nil || err != nil { + return -1, JoseHeader{}, nil, ErrCryptoFailure + } + + // The "zip" header parameter may only be present in the protected header. + if obj.protected.Zip != "" { + plaintext, err = decompress(obj.protected.Zip, plaintext) + } + + return index, headers.sanitized(), plaintext, err +} |