/
aes_ctr_duplex.go
92 lines (83 loc) · 2.13 KB
/
aes_ctr_duplex.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
package aes_ctr_duplex
import (
"crypto"
"crypto/aes"
"crypto/cipher"
"github.com/nwtgck/go-piping-tunnel/util"
"golang.org/x/crypto/pbkdf2"
"io"
)
const saltLen = 64
const pbkdf2Iter = 4096
const keyLen = 32
type aesCtrDuplex struct {
encryptWriter io.WriteCloser
decryptedReader io.Reader
closeBaseReader func() error
}
func Duplex(baseWriter io.WriteCloser, baseReader io.ReadCloser, passphrase []byte) (*aesCtrDuplex, error) {
// Generate salt
salt1, err := util.GenerateRandomBytes(saltLen)
if err != nil {
return nil, err
}
// Send the salt
if _, err := baseWriter.Write(salt1); err != nil {
return nil, err
}
// Derive key from passphrase
key1 := pbkdf2.Key(passphrase, salt1, pbkdf2Iter, keyLen, crypto.SHA512.New)
block, err := aes.NewCipher(key1)
if err != nil {
return nil, err
}
// Generate IV
iv1, err := util.GenerateRandomBytes(aes.BlockSize)
if err != nil {
return nil, err
}
// Send the IV
if _, err := baseWriter.Write(iv1); err != nil {
return nil, err
}
encryptWriter := &cipher.StreamWriter{
S: cipher.NewCTR(block, iv1),
W: baseWriter,
}
block, err = aes.NewCipher(key1)
if err != nil {
return nil, err
}
// Read salt from peer
salt2 := make([]byte, saltLen)
if _, err := io.ReadFull(baseReader, salt2); err != nil {
return nil, err
}
// Read IV from peer
iv2 := make([]byte, aes.BlockSize)
if _, err := io.ReadFull(baseReader, iv2); err != nil {
return nil, err
}
// Derive key from passphrase
key2 := pbkdf2.Key(passphrase, salt2, pbkdf2Iter, keyLen, crypto.SHA512.New)
block2, err := aes.NewCipher(key2)
if err != nil {
return nil, err
}
decryptedReader := &cipher.StreamReader{
S: cipher.NewCTR(block2, iv2),
R: baseReader,
}
return &aesCtrDuplex{encryptWriter: encryptWriter, decryptedReader: decryptedReader, closeBaseReader: baseReader.Close}, nil
}
func (d *aesCtrDuplex) Write(p []byte) (int, error) {
return d.encryptWriter.Write(p)
}
func (d *aesCtrDuplex) Read(p []byte) (int, error) {
return d.decryptedReader.Read(p)
}
func (d *aesCtrDuplex) Close() error {
wErr := d.encryptWriter.Close()
rErr := d.closeBaseReader()
return util.CombineErrors(wErr, rErr)
}