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mirror of https://github.com/v2fly/v2ray-core.git synced 2024-12-22 18:17:52 -05:00
v2fly/proxy/mtproto/auth.go
2018-07-19 13:31:57 +02:00

118 lines
2.5 KiB
Go

package mtproto
import (
"crypto/rand"
"crypto/sha256"
"io"
"sync"
"v2ray.com/core/common"
)
const (
HeaderSize = 64
)
type Authentication struct {
Header [HeaderSize]byte
DecodingKey [32]byte
EncodingKey [32]byte
DecodingNonce [16]byte
EncodingNonce [16]byte
}
func (a *Authentication) DataCenterID() uint16 {
x := ((int16(a.Header[61]) << 8) | int16(a.Header[60]))
if x < 0 {
x = -x
}
return uint16(x) - 1
}
func (a *Authentication) ApplySecret(b []byte) {
a.DecodingKey = sha256.Sum256(append(a.DecodingKey[:], b...))
a.EncodingKey = sha256.Sum256(append(a.EncodingKey[:], b...))
}
func generateRandomBytes(random []byte) {
for {
common.Must2(rand.Read(random))
if random[0] == 0xef {
continue
}
val := (uint32(random[3]) << 24) | (uint32(random[2]) << 16) | (uint32(random[1]) << 8) | uint32(random[0])
if val == 0x44414548 || val == 0x54534f50 || val == 0x20544547 || val == 0x4954504f || val == 0xeeeeeeee {
continue
}
if 0x00000000 == (uint32(random[7])<<24)|(uint32(random[6])<<16)|(uint32(random[5])<<8)|uint32(random[4]) {
continue
}
random[56] = 0xef
random[57] = 0xef
random[58] = 0xef
random[59] = 0xef
return
}
}
func NewAuthentication() *Authentication {
auth := getAuthenticationObject()
random := auth.Header[:]
generateRandomBytes(random)
copy(auth.EncodingKey[:], random[8:])
copy(auth.EncodingNonce[:], random[8+32:])
keyivInverse := Inverse(random[8 : 8+32+16])
copy(auth.DecodingKey[:], keyivInverse)
copy(auth.DecodingNonce[:], keyivInverse[32:])
return auth
}
func ReadAuthentication(reader io.Reader) (*Authentication, error) {
auth := getAuthenticationObject()
if _, err := io.ReadFull(reader, auth.Header[:]); err != nil {
putAuthenticationObject(auth)
return nil, err
}
copy(auth.DecodingKey[:], auth.Header[8:])
copy(auth.DecodingNonce[:], auth.Header[8+32:])
keyivInverse := Inverse(auth.Header[8 : 8+32+16])
copy(auth.EncodingKey[:], keyivInverse)
copy(auth.EncodingNonce[:], keyivInverse[32:])
return auth, nil
}
// Inverse returns a new byte array. It is a sequence of bytes when the input is read from end to beginning.Inverse
// Visible for testing only.
func Inverse(b []byte) []byte {
lenb := len(b)
b2 := make([]byte, lenb)
for i, v := range b {
b2[lenb-i-1] = v
}
return b2
}
var (
authPool = sync.Pool{
New: func() interface{} {
return new(Authentication)
},
}
)
func getAuthenticationObject() *Authentication {
return authPool.Get().(*Authentication)
}
func putAuthenticationObject(auth *Authentication) {
authPool.Put(auth)
}