136 lines
3.6 KiB
Go
136 lines
3.6 KiB
Go
/*
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* MinIO Cloud Storage, (C) 2018 MinIO, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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package madmin
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import (
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"bytes"
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"errors"
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"io"
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"io/ioutil"
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"github.com/secure-io/sio-go"
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"github.com/secure-io/sio-go/sioutil"
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"golang.org/x/crypto/argon2"
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)
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// EncryptData encrypts the data with an unique key
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// derived from password using the Argon2id PBKDF.
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//
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// The returned ciphertext data consists of:
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// salt | AEAD ID | nonce | encrypted data
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// 32 1 8 ~ len(data)
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func EncryptData(password string, data []byte) ([]byte, error) {
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salt := sioutil.MustRandom(32)
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// Derive an unique 256 bit key from the password and the random salt.
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key := argon2.IDKey([]byte(password), salt, 1, 64*1024, 4, 32)
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var (
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id byte
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err error
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stream *sio.Stream
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)
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if sioutil.NativeAES() { // Only use AES-GCM if we can use an optimized implementation
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id = aesGcm
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stream, err = sio.AES_256_GCM.Stream(key)
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} else {
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id = c20p1305
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stream, err = sio.ChaCha20Poly1305.Stream(key)
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}
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if err != nil {
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return nil, err
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}
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nonce := sioutil.MustRandom(stream.NonceSize())
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// ciphertext = salt || AEAD ID | nonce | encrypted data
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cLen := int64(len(salt)+1+len(nonce)+len(data)) + stream.Overhead(int64(len(data)))
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ciphertext := bytes.NewBuffer(make([]byte, 0, cLen)) // pre-alloc correct length
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// Prefix the ciphertext with salt, AEAD ID and nonce
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ciphertext.Write(salt)
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ciphertext.WriteByte(id)
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ciphertext.Write(nonce)
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w := stream.EncryptWriter(ciphertext, nonce, nil)
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if _, err = w.Write(data); err != nil {
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return nil, err
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}
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if err = w.Close(); err != nil {
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return nil, err
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}
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return ciphertext.Bytes(), nil
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}
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// ErrMaliciousData indicates that the stream cannot be
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// decrypted by provided credentials.
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var ErrMaliciousData = sio.NotAuthentic
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// DecryptData decrypts the data with the key derived
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// from the salt (part of data) and the password using
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// the PBKDF used in EncryptData. DecryptData returns
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// the decrypted plaintext on success.
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//
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// The data must be a valid ciphertext produced by
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// EncryptData. Otherwise, the decryption will fail.
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func DecryptData(password string, data io.Reader) ([]byte, error) {
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var (
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salt [32]byte
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id [1]byte
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nonce [8]byte // This depends on the AEAD but both used ciphers have the same nonce length.
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)
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if _, err := io.ReadFull(data, salt[:]); err != nil {
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return nil, err
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}
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if _, err := io.ReadFull(data, id[:]); err != nil {
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return nil, err
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}
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if _, err := io.ReadFull(data, nonce[:]); err != nil {
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return nil, err
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}
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key := argon2.IDKey([]byte(password), salt[:], 1, 64*1024, 4, 32)
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var (
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err error
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stream *sio.Stream
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)
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switch id[0] {
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case aesGcm:
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stream, err = sio.AES_256_GCM.Stream(key)
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case c20p1305:
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stream, err = sio.ChaCha20Poly1305.Stream(key)
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default:
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err = errors.New("madmin: invalid AEAD algorithm ID")
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}
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if err != nil {
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return nil, err
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}
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enBytes, err := ioutil.ReadAll(stream.DecryptReader(data, nonce[:], nil))
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if err != nil {
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if err == sio.NotAuthentic {
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return enBytes, ErrMaliciousData
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}
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}
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return enBytes, err
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}
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const (
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aesGcm = 0x00
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c20p1305 = 0x01
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)
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