diff options
Diffstat (limited to 'vendor/gopkg.in/square/go-jose.v2/asymmetric.go')
| -rw-r--r-- | vendor/gopkg.in/square/go-jose.v2/asymmetric.go | 592 |
1 files changed, 592 insertions, 0 deletions
diff --git a/vendor/gopkg.in/square/go-jose.v2/asymmetric.go b/vendor/gopkg.in/square/go-jose.v2/asymmetric.go new file mode 100644 index 000000000..67935561b --- /dev/null +++ b/vendor/gopkg.in/square/go-jose.v2/asymmetric.go @@ -0,0 +1,592 @@ +/*- + * 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" + + "golang.org/x/crypto/ed25519" + "gopkg.in/square/go-jose.v2/cipher" + "gopkg.in/square/go-jose.v2/json" +) + +// 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 +} + +type edEncrypterVerifier struct { + publicKey ed25519.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 +} + +type edDecrypterSigner struct { + privateKey ed25519.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: staticPublicKey(&JSONWebKey{ + Key: privateKey.Public(), + }), + signer: &rsaDecrypterSigner{ + privateKey: privateKey, + }, + }, nil +} + +func newEd25519Signer(sigAlg SignatureAlgorithm, privateKey ed25519.PrivateKey) (recipientSigInfo, error) { + if sigAlg != EdDSA { + return recipientSigInfo{}, ErrUnsupportedAlgorithm + } + + if privateKey == nil { + return recipientSigInfo{}, errors.New("invalid private key") + } + return recipientSigInfo{ + sigAlg: sigAlg, + publicKey: staticPublicKey(&JSONWebKey{ + Key: privateKey.Public(), + }), + signer: &edDecrypterSigner{ + 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: staticPublicKey(&JSONWebKey{ + Key: privateKey.Public(), + }), + 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, headers.getAlgorithm(), 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) + + b, err := json.Marshal(&JSONWebKey{ + Key: &priv.PublicKey, + }) + if err != nil { + return nil, nil, err + } + + headers := rawHeader{ + headerEPK: makeRawMessage(b), + } + + 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) { + epk, err := headers.getEPK() + if err != nil { + return nil, errors.New("square/go-jose: invalid epk header") + } + if epk == nil { + return nil, errors.New("square/go-jose: missing epk header") + } + + publicKey, ok := 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, err := headers.getAPU() + if err != nil { + return nil, errors.New("square/go-jose: invalid apu header") + } + apvData, err := headers.getAPV() + if err != nil { + return nil, errors.New("square/go-jose: invalid apv header") + } + + deriveKey := func(algID string, size int) []byte { + return josecipher.DeriveECDHES(algID, apuData.bytes(), apvData.bytes(), ctx.privateKey, publicKey, size) + } + + var keySize int + + algorithm := headers.getAlgorithm() + switch algorithm { + case ECDH_ES: + // ECDH-ES uses direct key agreement, no key unwrapping necessary. + return deriveKey(string(headers.getEncryption()), 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(string(algorithm), keySize) + block, err := aes.NewCipher(key) + if err != nil { + return nil, err + } + + return josecipher.KeyUnwrap(block, recipient.encryptedKey) +} + +func (ctx edDecrypterSigner) signPayload(payload []byte, alg SignatureAlgorithm) (Signature, error) { + if alg != EdDSA { + return Signature{}, ErrUnsupportedAlgorithm + } + + sig, err := ctx.privateKey.Sign(RandReader, payload, crypto.Hash(0)) + if err != nil { + return Signature{}, err + } + + return Signature{ + Signature: sig, + protected: &rawHeader{}, + }, nil +} + +func (ctx edEncrypterVerifier) verifyPayload(payload []byte, signature []byte, alg SignatureAlgorithm) error { + if alg != EdDSA { + return ErrUnsupportedAlgorithm + } + ok := ed25519.Verify(ctx.publicKey, payload, signature) + if !ok { + return errors.New("square/go-jose: ed25519 signature failed to verify") + } + return nil +} + +// 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++ + } + + // We serialize the outputs (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 +} |