/
aead.go
104 lines (87 loc) · 2.62 KB
/
aead.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
99
100
101
102
103
104
package handshake
import (
"crypto/cipher"
"encoding/binary"
"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/protocol"
)
type sealer struct {
aead cipher.AEAD
hpEncrypter cipher.Block
// use a single slice to avoid allocations
nonceBuf []byte
hpMask []byte
// short headers protect 5 bits in the first byte, long headers only 4
is1RTT bool
}
var _ Sealer = &sealer{}
func newSealer(aead cipher.AEAD, hpEncrypter cipher.Block, is1RTT bool) Sealer {
return &sealer{
aead: aead,
nonceBuf: make([]byte, aead.NonceSize()),
is1RTT: is1RTT,
hpEncrypter: hpEncrypter,
hpMask: make([]byte, hpEncrypter.BlockSize()),
}
}
func (s *sealer) Seal(dst, src []byte, pn protocol.PacketNumber, ad []byte) []byte {
binary.BigEndian.PutUint64(s.nonceBuf[len(s.nonceBuf)-8:], uint64(pn))
// The AEAD we're using here will be the qtls.aeadAESGCM13.
// It uses the nonce provided here and XOR it with the IV.
return s.aead.Seal(dst, s.nonceBuf, src, ad)
}
func (s *sealer) EncryptHeader(sample []byte, firstByte *byte, pnBytes []byte) {
if len(sample) != s.hpEncrypter.BlockSize() {
panic("invalid sample size")
}
s.hpEncrypter.Encrypt(s.hpMask, sample)
if s.is1RTT {
*firstByte ^= s.hpMask[0] & 0x1f
} else {
*firstByte ^= s.hpMask[0] & 0xf
}
for i := range pnBytes {
pnBytes[i] ^= s.hpMask[i+1]
}
}
func (s *sealer) Overhead() int {
return s.aead.Overhead()
}
type opener struct {
aead cipher.AEAD
pnDecrypter cipher.Block
// use a single slice to avoid allocations
nonceBuf []byte
hpMask []byte
// short headers protect 5 bits in the first byte, long headers only 4
is1RTT bool
}
var _ Opener = &opener{}
func newOpener(aead cipher.AEAD, pnDecrypter cipher.Block, is1RTT bool) Opener {
return &opener{
aead: aead,
nonceBuf: make([]byte, aead.NonceSize()),
is1RTT: is1RTT,
pnDecrypter: pnDecrypter,
hpMask: make([]byte, pnDecrypter.BlockSize()),
}
}
func (o *opener) Open(dst, src []byte, pn protocol.PacketNumber, ad []byte) ([]byte, error) {
binary.BigEndian.PutUint64(o.nonceBuf[len(o.nonceBuf)-8:], uint64(pn))
// The AEAD we're using here will be the qtls.aeadAESGCM13.
// It uses the nonce provided here and XOR it with the IV.
return o.aead.Open(dst, o.nonceBuf, src, ad)
}
func (o *opener) DecryptHeader(sample []byte, firstByte *byte, pnBytes []byte) {
if len(sample) != o.pnDecrypter.BlockSize() {
panic("invalid sample size")
}
o.pnDecrypter.Encrypt(o.hpMask, sample)
if o.is1RTT {
*firstByte ^= o.hpMask[0] & 0x1f
} else {
*firstByte ^= o.hpMask[0] & 0xf
}
for i := range pnBytes {
pnBytes[i] ^= o.hpMask[i+1]
}
}