mirror of
https://github.com/woodpecker-ci/woodpecker.git
synced 2024-12-12 03:26:30 +00:00
348 lines
7.9 KiB
Go
348 lines
7.9 KiB
Go
/*-
|
|
* 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/aes"
|
|
"crypto/cipher"
|
|
"crypto/hmac"
|
|
"crypto/rand"
|
|
"crypto/sha256"
|
|
"crypto/sha512"
|
|
"crypto/subtle"
|
|
"errors"
|
|
"github.com/square/go-jose/cipher"
|
|
"hash"
|
|
"io"
|
|
)
|
|
|
|
// Random reader (stubbed out in tests)
|
|
var randReader = rand.Reader
|
|
|
|
// Dummy key cipher for shared symmetric key mode
|
|
type symmetricKeyCipher struct {
|
|
key []byte // Pre-shared content-encryption key
|
|
}
|
|
|
|
// Signer/verifier for MAC modes
|
|
type symmetricMac struct {
|
|
key []byte
|
|
}
|
|
|
|
// Input/output from an AEAD operation
|
|
type aeadParts struct {
|
|
iv, ciphertext, tag []byte
|
|
}
|
|
|
|
// A content cipher based on an AEAD construction
|
|
type aeadContentCipher struct {
|
|
keyBytes int
|
|
authtagBytes int
|
|
getAead func(key []byte) (cipher.AEAD, error)
|
|
}
|
|
|
|
// Random key generator
|
|
type randomKeyGenerator struct {
|
|
size int
|
|
}
|
|
|
|
// Static key generator
|
|
type staticKeyGenerator struct {
|
|
key []byte
|
|
}
|
|
|
|
// Create a new content cipher based on AES-GCM
|
|
func newAESGCM(keySize int) contentCipher {
|
|
return &aeadContentCipher{
|
|
keyBytes: keySize,
|
|
authtagBytes: 16,
|
|
getAead: func(key []byte) (cipher.AEAD, error) {
|
|
aes, err := aes.NewCipher(key)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return cipher.NewGCM(aes)
|
|
},
|
|
}
|
|
}
|
|
|
|
// Create a new content cipher based on AES-CBC+HMAC
|
|
func newAESCBC(keySize int) contentCipher {
|
|
return &aeadContentCipher{
|
|
keyBytes: keySize * 2,
|
|
authtagBytes: 16,
|
|
getAead: func(key []byte) (cipher.AEAD, error) {
|
|
return josecipher.NewCBCHMAC(key, aes.NewCipher)
|
|
},
|
|
}
|
|
}
|
|
|
|
// Get an AEAD cipher object for the given content encryption algorithm
|
|
func getContentCipher(alg ContentEncryption) contentCipher {
|
|
switch alg {
|
|
case A128GCM:
|
|
return newAESGCM(16)
|
|
case A192GCM:
|
|
return newAESGCM(24)
|
|
case A256GCM:
|
|
return newAESGCM(32)
|
|
case A128CBC_HS256:
|
|
return newAESCBC(16)
|
|
case A192CBC_HS384:
|
|
return newAESCBC(24)
|
|
case A256CBC_HS512:
|
|
return newAESCBC(32)
|
|
default:
|
|
return nil
|
|
}
|
|
}
|
|
|
|
// newSymmetricRecipient creates a JWE encrypter based on AES-GCM key wrap.
|
|
func newSymmetricRecipient(keyAlg KeyAlgorithm, key []byte) (recipientKeyInfo, error) {
|
|
switch keyAlg {
|
|
case DIRECT, A128GCMKW, A192GCMKW, A256GCMKW, A128KW, A192KW, A256KW:
|
|
default:
|
|
return recipientKeyInfo{}, ErrUnsupportedAlgorithm
|
|
}
|
|
|
|
return recipientKeyInfo{
|
|
keyAlg: keyAlg,
|
|
keyEncrypter: &symmetricKeyCipher{
|
|
key: key,
|
|
},
|
|
}, nil
|
|
}
|
|
|
|
// newSymmetricSigner creates a recipientSigInfo based on the given key.
|
|
func newSymmetricSigner(sigAlg SignatureAlgorithm, key []byte) (recipientSigInfo, error) {
|
|
// Verify that key management algorithm is supported by this encrypter
|
|
switch sigAlg {
|
|
case HS256, HS384, HS512:
|
|
default:
|
|
return recipientSigInfo{}, ErrUnsupportedAlgorithm
|
|
}
|
|
|
|
return recipientSigInfo{
|
|
sigAlg: sigAlg,
|
|
signer: &symmetricMac{
|
|
key: key,
|
|
},
|
|
}, nil
|
|
}
|
|
|
|
// Generate a random key for the given content cipher
|
|
func (ctx randomKeyGenerator) genKey() ([]byte, rawHeader, error) {
|
|
key := make([]byte, ctx.size)
|
|
_, err := io.ReadFull(randReader, key)
|
|
if err != nil {
|
|
return nil, rawHeader{}, err
|
|
}
|
|
|
|
return key, rawHeader{}, nil
|
|
}
|
|
|
|
// Key size for random generator
|
|
func (ctx randomKeyGenerator) keySize() int {
|
|
return ctx.size
|
|
}
|
|
|
|
// Generate a static key (for direct mode)
|
|
func (ctx staticKeyGenerator) genKey() ([]byte, rawHeader, error) {
|
|
cek := make([]byte, len(ctx.key))
|
|
copy(cek, ctx.key)
|
|
return cek, rawHeader{}, nil
|
|
}
|
|
|
|
// Key size for static generator
|
|
func (ctx staticKeyGenerator) keySize() int {
|
|
return len(ctx.key)
|
|
}
|
|
|
|
// Get key size for this cipher
|
|
func (ctx aeadContentCipher) keySize() int {
|
|
return ctx.keyBytes
|
|
}
|
|
|
|
// Encrypt some data
|
|
func (ctx aeadContentCipher) encrypt(key, aad, pt []byte) (*aeadParts, error) {
|
|
// Get a new AEAD instance
|
|
aead, err := ctx.getAead(key)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Initialize a new nonce
|
|
iv := make([]byte, aead.NonceSize())
|
|
_, err = io.ReadFull(randReader, iv)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
ciphertextAndTag := aead.Seal(nil, iv, pt, aad)
|
|
offset := len(ciphertextAndTag) - ctx.authtagBytes
|
|
|
|
return &aeadParts{
|
|
iv: iv,
|
|
ciphertext: ciphertextAndTag[:offset],
|
|
tag: ciphertextAndTag[offset:],
|
|
}, nil
|
|
}
|
|
|
|
// Decrypt some data
|
|
func (ctx aeadContentCipher) decrypt(key, aad []byte, parts *aeadParts) ([]byte, error) {
|
|
aead, err := ctx.getAead(key)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return aead.Open(nil, parts.iv, append(parts.ciphertext, parts.tag...), aad)
|
|
}
|
|
|
|
// Encrypt the content encryption key.
|
|
func (ctx *symmetricKeyCipher) encryptKey(cek []byte, alg KeyAlgorithm) (recipientInfo, error) {
|
|
switch alg {
|
|
case DIRECT:
|
|
return recipientInfo{
|
|
header: &rawHeader{},
|
|
}, nil
|
|
case A128GCMKW, A192GCMKW, A256GCMKW:
|
|
aead := newAESGCM(len(ctx.key))
|
|
|
|
parts, err := aead.encrypt(ctx.key, []byte{}, cek)
|
|
if err != nil {
|
|
return recipientInfo{}, err
|
|
}
|
|
|
|
return recipientInfo{
|
|
header: &rawHeader{
|
|
Iv: newBuffer(parts.iv),
|
|
Tag: newBuffer(parts.tag),
|
|
},
|
|
encryptedKey: parts.ciphertext,
|
|
}, nil
|
|
case A128KW, A192KW, A256KW:
|
|
block, err := aes.NewCipher(ctx.key)
|
|
if err != nil {
|
|
return recipientInfo{}, err
|
|
}
|
|
|
|
jek, err := josecipher.KeyWrap(block, cek)
|
|
if err != nil {
|
|
return recipientInfo{}, err
|
|
}
|
|
|
|
return recipientInfo{
|
|
encryptedKey: jek,
|
|
header: &rawHeader{},
|
|
}, nil
|
|
}
|
|
|
|
return recipientInfo{}, ErrUnsupportedAlgorithm
|
|
}
|
|
|
|
// Decrypt the content encryption key.
|
|
func (ctx *symmetricKeyCipher) decryptKey(headers rawHeader, recipient *recipientInfo, generator keyGenerator) ([]byte, error) {
|
|
switch KeyAlgorithm(headers.Alg) {
|
|
case DIRECT:
|
|
cek := make([]byte, len(ctx.key))
|
|
copy(cek, ctx.key)
|
|
return cek, nil
|
|
case A128GCMKW, A192GCMKW, A256GCMKW:
|
|
aead := newAESGCM(len(ctx.key))
|
|
|
|
parts := &aeadParts{
|
|
iv: headers.Iv.bytes(),
|
|
ciphertext: recipient.encryptedKey,
|
|
tag: headers.Tag.bytes(),
|
|
}
|
|
|
|
cek, err := aead.decrypt(ctx.key, []byte{}, parts)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return cek, nil
|
|
case A128KW, A192KW, A256KW:
|
|
block, err := aes.NewCipher(ctx.key)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
cek, err := josecipher.KeyUnwrap(block, recipient.encryptedKey)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return cek, nil
|
|
}
|
|
|
|
return nil, ErrUnsupportedAlgorithm
|
|
}
|
|
|
|
// Sign the given payload
|
|
func (ctx symmetricMac) signPayload(payload []byte, alg SignatureAlgorithm) (Signature, error) {
|
|
mac, err := ctx.hmac(payload, alg)
|
|
if err != nil {
|
|
return Signature{}, errors.New("square/go-jose: failed to compute hmac")
|
|
}
|
|
|
|
return Signature{
|
|
signature: mac,
|
|
protected: &rawHeader{},
|
|
}, nil
|
|
}
|
|
|
|
// Verify the given payload
|
|
func (ctx symmetricMac) verifyPayload(payload []byte, mac []byte, alg SignatureAlgorithm) error {
|
|
expected, err := ctx.hmac(payload, alg)
|
|
if err != nil {
|
|
return errors.New("square/go-jose: failed to compute hmac")
|
|
}
|
|
|
|
if len(mac) != len(expected) {
|
|
return errors.New("square/go-jose: invalid hmac")
|
|
}
|
|
|
|
match := subtle.ConstantTimeCompare(mac, expected)
|
|
if match != 1 {
|
|
return errors.New("square/go-jose: invalid hmac")
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Compute the HMAC based on the given alg value
|
|
func (ctx symmetricMac) hmac(payload []byte, alg SignatureAlgorithm) ([]byte, error) {
|
|
var hash func() hash.Hash
|
|
|
|
switch alg {
|
|
case HS256:
|
|
hash = sha256.New
|
|
case HS384:
|
|
hash = sha512.New384
|
|
case HS512:
|
|
hash = sha512.New
|
|
default:
|
|
return nil, ErrUnsupportedAlgorithm
|
|
}
|
|
|
|
hmac := hmac.New(hash, ctx.key)
|
|
|
|
// According to documentation, Write() on hash never fails
|
|
_, _ = hmac.Write(payload)
|
|
return hmac.Sum(nil), nil
|
|
}
|