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Add own implementation of PKCS#8 key encryption
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This is inspired by [1] (Apache-2.0 license)

[1]: https://github.com/smallstep/crypto
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weinimo committed Sep 18, 2024
1 parent 014f603 commit 234d68f
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Showing 3 changed files with 155 additions and 158 deletions.
7 changes: 1 addition & 6 deletions pkg/octavia/amphora_certs.go
Original file line number Diff line number Diff line change
Expand Up @@ -60,12 +60,7 @@ func generateKey(passphrase []byte) (*rsa.PrivateKey, []byte, error) {

var pemBlock *pem.Block
if passphrase != nil {
pemBlock, err = EncryptPEMBlock(
rand.Reader,
"PRIVATE KEY",
pkcs8Key,
passphrase,
PEMCipherAES128)
pemBlock, err = EncryptPrivateKey(pkcs8Key, passphrase)
if err != nil {
err = fmt.Errorf("Error encrypting private key: %w", err)
return priv, nil, err
Expand Down
152 changes: 0 additions & 152 deletions pkg/octavia/pem_decrypt_fips.go

This file was deleted.

154 changes: 154 additions & 0 deletions pkg/octavia/pkcs8_aes.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,154 @@
/*
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 octavia

import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"crypto/sha256"
"encoding/asn1"
"encoding/pem"
"fmt"

"golang.org/x/crypto/pbkdf2"
)

var (
// key derivation functions
oidPKCS5PBKDF2 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 5, 12}
oidPBES2 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 5, 13}
oidHMACWithSHA256 = asn1.ObjectIdentifier{1, 2, 840, 113549, 2, 9}

// encryption
oidAES256CBC = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 1, 42}
)

// Encrypted pkcs8
// Based on https://github.com/youmark/pkcs8
// MIT license
type prfParam struct {
Algo asn1.ObjectIdentifier
NullParam asn1.RawValue
}

type pbkdf2Params struct {
Salt []byte
IterationCount int
PrfParam prfParam `asn1:"optional"`
}

type pbkdf2Algorithms struct {
Algo asn1.ObjectIdentifier
PBKDF2Params pbkdf2Params
}

type pbkdf2Encs struct {
EncryAlgo asn1.ObjectIdentifier
IV []byte
}

type pbes2Params struct {
KeyDerivationFunc pbkdf2Algorithms
EncryptionScheme pbkdf2Encs
}

type encryptedlAlgorithmIdentifier struct {
Algorithm asn1.ObjectIdentifier
Parameters pbes2Params
}

type encryptedPrivateKeyInfo struct {
Algo encryptedlAlgorithmIdentifier
PrivateKey []byte
}

// EncryptPrivateKey encrypts given private key data using AES in PKCS#8 format
func EncryptPrivateKey(data, password []byte) (*pem.Block, error) {
pbkdf2Iterations := 600000
aes256Keysize := 32
dataLength := len(data)
padSize := aes.BlockSize - dataLength%aes.BlockSize
encryptedSize := dataLength + padSize

// Generate salt using random data
pbkdf2Salt := make([]byte, 16)
_, err := rand.Read(pbkdf2Salt)
if err != nil {
err = fmt.Errorf("error generating random data for salt for private key encryption: %w", err)
return nil, err
}

iv := make([]byte, aes.BlockSize)
_, err = rand.Read(iv)
if err != nil {
err = fmt.Errorf("error generating random data for init vector for private key encryption: %w", err)
return nil, err
}

key := pbkdf2.Key(password, pbkdf2Salt, pbkdf2Iterations,
aes256Keysize, sha256.New)
encryptedBlock, err := aes.NewCipher(key)
if err != nil {
err = fmt.Errorf("error creating new cipher block for private key encryption: %w", err)
return nil, err
}

cryptSource := make([]byte, encryptedSize)
copy(cryptSource, data)
// Set padding data according to RFC1423, 1.1
for i := dataLength; i < encryptedSize; i++ {
cryptSource[i] = byte(padSize)
}
encrypted := make([]byte, encryptedSize)

encrypter := cipher.NewCBCEncrypter(encryptedBlock, iv)
encrypter.CryptBlocks(encrypted, cryptSource)

// Build encrypted ans1 data
pki := encryptedPrivateKeyInfo{
Algo: encryptedlAlgorithmIdentifier{
Algorithm: oidPBES2,
Parameters: pbes2Params{
KeyDerivationFunc: pbkdf2Algorithms{
Algo: oidPKCS5PBKDF2,
PBKDF2Params: pbkdf2Params{
Salt: pbkdf2Salt,
IterationCount: pbkdf2Iterations,
PrfParam: prfParam{
Algo: oidHMACWithSHA256,
NullParam: asn1.NullRawValue,
},
},
},
EncryptionScheme: pbkdf2Encs{
EncryAlgo: oidAES256CBC,
IV: iv,
},
},
},
PrivateKey: encrypted,
}

b, err := asn1.Marshal(pki)
if err != nil {
err = fmt.Errorf("error marshaling encrypted key: %w", err)
return nil, err
}
return &pem.Block{
Type: "ENCRYPTED PRIVATE KEY",
Bytes: b,
}, nil
}

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