/
encryption.go
98 lines (79 loc) · 1.81 KB
/
encryption.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
93
94
95
96
97
98
package initializer
import (
"context"
"crypto/aes"
"crypto/cipher"
"fmt"
"io"
"sync"
"github.com/djosix/med/internal"
"github.com/djosix/med/internal/helper"
)
func InitEncryption(secret []byte) Initializer {
return func(ctx context.Context, rwc io.ReadWriteCloser) (ctxOut context.Context, rwcOut io.ReadWriteCloser, err error) {
initLogger.Debug("encryption")
secret := secret
if secret == nil {
b, ok := ctx.Value("secret").([]byte)
if !ok {
err = fmt.Errorf("secret not in context")
return
}
secret = b
}
ctxOut = ctx
rw, err := NewEncryptionLayer(rwc, secret)
rwcOut = helper.NewReadWriterCloser(rw, rw, rwc)
return
}
}
type EncryptionLayer struct {
io.ReadWriter
readStream cipher.Stream
readMutex sync.Mutex
writeStream cipher.Stream
writeMutex sync.Mutex
}
func NewEncryptionLayer(rw io.ReadWriter, secret []byte) (*EncryptionLayer, error) {
hash := helper.Hash256(secret)
key, iv := hash[:16], hash[16:]
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
el := EncryptionLayer{
ReadWriter: rw,
readStream: cipher.NewCTR(block, iv),
readMutex: sync.Mutex{},
writeStream: cipher.NewCTR(block, iv),
writeMutex: sync.Mutex{},
}
return &el, nil
}
func (el *EncryptionLayer) Read(p []byte) (n int, err error) {
el.readMutex.Lock()
defer el.readMutex.Unlock()
buf := make([]byte, len(p)) // TODO
n, err = el.ReadWriter.Read(buf)
if err != nil {
return
}
if n > 0 {
el.readStream.XORKeyStream(p, buf[:n])
}
return
}
func (el *EncryptionLayer) Write(p []byte) (n int, err error) {
el.writeMutex.Lock()
defer el.writeMutex.Unlock()
buf := make([]byte, len(p))
el.writeStream.XORKeyStream(buf, p)
n, err = el.ReadWriter.Write(buf)
if err != nil {
return
}
if n != len(p) {
panic(internal.Unexpected)
}
return
}