Xray-core/proxy/vless/encryption/xor.go

94 lines
1.9 KiB
Go

package encryption
import (
"crypto/aes"
"crypto/cipher"
"net"
"lukechampine.com/blake3"
)
func NewCTR(key, iv []byte) cipher.Stream {
k := make([]byte, 32)
blake3.DeriveKey(k, "VLESS", key) // avoids using key directly
block, _ := aes.NewCipher(k)
return cipher.NewCTR(block, iv)
//chacha20.NewUnauthenticatedCipher()
}
type XorConn struct {
net.Conn
CTR cipher.Stream
PeerCTR cipher.Stream
OutSkip int
OutHeader []byte
InSkip int
InHeader []byte
}
func NewXorConn(conn net.Conn, ctr, peerCTR cipher.Stream, outSkip, inSkip int) *XorConn {
return &XorConn{
Conn: conn,
CTR: ctr,
PeerCTR: peerCTR,
OutSkip: outSkip,
OutHeader: make([]byte, 0, 5), // important
InSkip: inSkip,
InHeader: make([]byte, 0, 5), // important
}
}
func (c *XorConn) Write(b []byte) (int, error) {
if len(b) == 0 {
return 0, nil
}
for p := b; ; {
if len(p) <= c.OutSkip {
c.OutSkip -= len(p)
break
}
p = p[c.OutSkip:]
c.OutSkip = 0
need := 5 - len(c.OutHeader)
if len(p) < need {
c.OutHeader = append(c.OutHeader, p...)
c.CTR.XORKeyStream(p, p)
break
}
c.OutSkip, _ = DecodeHeader(append(c.OutHeader, p[:need]...))
c.OutHeader = c.OutHeader[:0]
c.CTR.XORKeyStream(p[:need], p[:need])
p = p[need:]
}
if _, err := c.Conn.Write(b); err != nil {
return 0, err
}
return len(b), nil
}
func (c *XorConn) Read(b []byte) (int, error) {
if len(b) == 0 {
return 0, nil
}
n, err := c.Conn.Read(b)
for p := b[:n]; ; {
if len(p) <= c.InSkip {
c.InSkip -= len(p)
break
}
p = p[c.InSkip:]
c.InSkip = 0
need := 5 - len(c.InHeader)
if len(p) < need {
c.PeerCTR.XORKeyStream(p, p)
c.InHeader = append(c.InHeader, p...)
break
}
c.PeerCTR.XORKeyStream(p[:need], p[:need])
c.InSkip, _ = DecodeHeader(append(c.InHeader, p[:need]...))
c.InHeader = c.InHeader[:0]
p = p[need:]
}
return n, err
}