mirror of
https://github.com/XTLS/Xray-core.git
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309 lines
7.9 KiB
Go
309 lines
7.9 KiB
Go
package shadowsocks
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import (
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"bytes"
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"crypto/aes"
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"crypto/cipher"
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"crypto/md5"
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"crypto/sha1"
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"io"
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"golang.org/x/crypto/chacha20poly1305"
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"golang.org/x/crypto/hkdf"
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"github.com/xtls/xray-core/common"
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"github.com/xtls/xray-core/common/buf"
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"github.com/xtls/xray-core/common/crypto"
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"github.com/xtls/xray-core/common/protocol"
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)
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// MemoryAccount is an account type converted from Account.
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type MemoryAccount struct {
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Cipher Cipher
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Key []byte
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}
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// Equals implements protocol.Account.Equals().
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func (a *MemoryAccount) Equals(another protocol.Account) bool {
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if account, ok := another.(*MemoryAccount); ok {
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return bytes.Equal(a.Key, account.Key)
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}
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return false
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}
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func createAesGcm(key []byte) cipher.AEAD {
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block, err := aes.NewCipher(key)
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common.Must(err)
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gcm, err := cipher.NewGCM(block)
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common.Must(err)
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return gcm
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}
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func createChacha20Poly1305(key []byte) cipher.AEAD {
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chacha20, err := chacha20poly1305.New(key)
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common.Must(err)
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return chacha20
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}
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func (a *Account) getCipher() (Cipher, error) {
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switch a.CipherType {
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case CipherType_AES_128_CFB:
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return &AesCfb{KeyBytes: 16}, nil
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case CipherType_AES_256_CFB:
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return &AesCfb{KeyBytes: 32}, nil
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case CipherType_CHACHA20:
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return &ChaCha20{IVBytes: 8}, nil
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case CipherType_CHACHA20_IETF:
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return &ChaCha20{IVBytes: 12}, nil
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case CipherType_AES_128_GCM:
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return &AEADCipher{
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KeyBytes: 16,
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IVBytes: 16,
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AEADAuthCreator: createAesGcm,
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}, nil
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case CipherType_AES_256_GCM:
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return &AEADCipher{
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KeyBytes: 32,
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IVBytes: 32,
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AEADAuthCreator: createAesGcm,
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}, nil
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case CipherType_CHACHA20_POLY1305:
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return &AEADCipher{
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KeyBytes: 32,
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IVBytes: 32,
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AEADAuthCreator: createChacha20Poly1305,
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}, nil
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case CipherType_NONE:
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return NoneCipher{}, nil
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default:
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return nil, newError("Unsupported cipher.")
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}
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}
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// AsAccount implements protocol.AsAccount.
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func (a *Account) AsAccount() (protocol.Account, error) {
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cipher, err := a.getCipher()
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if err != nil {
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return nil, newError("failed to get cipher").Base(err)
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}
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return &MemoryAccount{
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Cipher: cipher,
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Key: passwordToCipherKey([]byte(a.Password), cipher.KeySize()),
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}, nil
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}
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// Cipher is an interface for all Shadowsocks ciphers.
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type Cipher interface {
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KeySize() int32
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IVSize() int32
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NewEncryptionWriter(key []byte, iv []byte, writer io.Writer) (buf.Writer, error)
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NewDecryptionReader(key []byte, iv []byte, reader io.Reader) (buf.Reader, error)
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IsAEAD() bool
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EncodePacket(key []byte, b *buf.Buffer) error
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DecodePacket(key []byte, b *buf.Buffer) error
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}
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// AesCfb represents all AES-CFB ciphers.
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type AesCfb struct {
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KeyBytes int32
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}
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func (*AesCfb) IsAEAD() bool {
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return false
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}
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func (v *AesCfb) KeySize() int32 {
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return v.KeyBytes
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}
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func (v *AesCfb) IVSize() int32 {
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return 16
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}
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func (v *AesCfb) NewEncryptionWriter(key []byte, iv []byte, writer io.Writer) (buf.Writer, error) {
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stream := crypto.NewAesEncryptionStream(key, iv)
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return &buf.SequentialWriter{Writer: crypto.NewCryptionWriter(stream, writer)}, nil
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}
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func (v *AesCfb) NewDecryptionReader(key []byte, iv []byte, reader io.Reader) (buf.Reader, error) {
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stream := crypto.NewAesDecryptionStream(key, iv)
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return &buf.SingleReader{
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Reader: crypto.NewCryptionReader(stream, reader),
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}, nil
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}
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func (v *AesCfb) EncodePacket(key []byte, b *buf.Buffer) error {
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iv := b.BytesTo(v.IVSize())
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stream := crypto.NewAesEncryptionStream(key, iv)
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stream.XORKeyStream(b.BytesFrom(v.IVSize()), b.BytesFrom(v.IVSize()))
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return nil
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}
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func (v *AesCfb) DecodePacket(key []byte, b *buf.Buffer) error {
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if b.Len() <= v.IVSize() {
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return newError("insufficient data: ", b.Len())
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}
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iv := b.BytesTo(v.IVSize())
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stream := crypto.NewAesDecryptionStream(key, iv)
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stream.XORKeyStream(b.BytesFrom(v.IVSize()), b.BytesFrom(v.IVSize()))
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b.Advance(v.IVSize())
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return nil
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}
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type AEADCipher struct {
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KeyBytes int32
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IVBytes int32
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AEADAuthCreator func(key []byte) cipher.AEAD
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}
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func (*AEADCipher) IsAEAD() bool {
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return true
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}
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func (c *AEADCipher) KeySize() int32 {
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return c.KeyBytes
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}
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func (c *AEADCipher) IVSize() int32 {
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return c.IVBytes
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}
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func (c *AEADCipher) createAuthenticator(key []byte, iv []byte) *crypto.AEADAuthenticator {
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nonce := crypto.GenerateInitialAEADNonce()
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subkey := make([]byte, c.KeyBytes)
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hkdfSHA1(key, iv, subkey)
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return &crypto.AEADAuthenticator{
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AEAD: c.AEADAuthCreator(subkey),
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NonceGenerator: nonce,
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}
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}
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func (c *AEADCipher) NewEncryptionWriter(key []byte, iv []byte, writer io.Writer) (buf.Writer, error) {
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auth := c.createAuthenticator(key, iv)
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return crypto.NewAuthenticationWriter(auth, &crypto.AEADChunkSizeParser{
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Auth: auth,
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}, writer, protocol.TransferTypeStream, nil), nil
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}
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func (c *AEADCipher) NewDecryptionReader(key []byte, iv []byte, reader io.Reader) (buf.Reader, error) {
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auth := c.createAuthenticator(key, iv)
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return crypto.NewAuthenticationReader(auth, &crypto.AEADChunkSizeParser{
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Auth: auth,
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}, reader, protocol.TransferTypeStream, nil), nil
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}
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func (c *AEADCipher) EncodePacket(key []byte, b *buf.Buffer) error {
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ivLen := c.IVSize()
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payloadLen := b.Len()
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auth := c.createAuthenticator(key, b.BytesTo(ivLen))
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b.Extend(int32(auth.Overhead()))
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_, err := auth.Seal(b.BytesTo(ivLen), b.BytesRange(ivLen, payloadLen))
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return err
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}
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func (c *AEADCipher) DecodePacket(key []byte, b *buf.Buffer) error {
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if b.Len() <= c.IVSize() {
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return newError("insufficient data: ", b.Len())
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}
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ivLen := c.IVSize()
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payloadLen := b.Len()
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auth := c.createAuthenticator(key, b.BytesTo(ivLen))
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bbb, err := auth.Open(b.BytesTo(ivLen), b.BytesRange(ivLen, payloadLen))
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if err != nil {
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return err
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}
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b.Resize(ivLen, int32(len(bbb)))
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return nil
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}
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type ChaCha20 struct {
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IVBytes int32
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}
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func (*ChaCha20) IsAEAD() bool {
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return false
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}
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func (v *ChaCha20) KeySize() int32 {
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return 32
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}
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func (v *ChaCha20) IVSize() int32 {
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return v.IVBytes
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}
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func (v *ChaCha20) NewEncryptionWriter(key []byte, iv []byte, writer io.Writer) (buf.Writer, error) {
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stream := crypto.NewChaCha20Stream(key, iv)
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return &buf.SequentialWriter{Writer: crypto.NewCryptionWriter(stream, writer)}, nil
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}
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func (v *ChaCha20) NewDecryptionReader(key []byte, iv []byte, reader io.Reader) (buf.Reader, error) {
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stream := crypto.NewChaCha20Stream(key, iv)
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return &buf.SingleReader{Reader: crypto.NewCryptionReader(stream, reader)}, nil
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}
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func (v *ChaCha20) EncodePacket(key []byte, b *buf.Buffer) error {
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iv := b.BytesTo(v.IVSize())
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stream := crypto.NewChaCha20Stream(key, iv)
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stream.XORKeyStream(b.BytesFrom(v.IVSize()), b.BytesFrom(v.IVSize()))
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return nil
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}
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func (v *ChaCha20) DecodePacket(key []byte, b *buf.Buffer) error {
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if b.Len() <= v.IVSize() {
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return newError("insufficient data: ", b.Len())
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}
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iv := b.BytesTo(v.IVSize())
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stream := crypto.NewChaCha20Stream(key, iv)
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stream.XORKeyStream(b.BytesFrom(v.IVSize()), b.BytesFrom(v.IVSize()))
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b.Advance(v.IVSize())
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return nil
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}
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type NoneCipher struct{}
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func (NoneCipher) KeySize() int32 { return 0 }
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func (NoneCipher) IVSize() int32 { return 0 }
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func (NoneCipher) IsAEAD() bool {
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return true // to avoid OTA
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}
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func (NoneCipher) NewDecryptionReader(key []byte, iv []byte, reader io.Reader) (buf.Reader, error) {
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return buf.NewReader(reader), nil
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}
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func (NoneCipher) NewEncryptionWriter(key []byte, iv []byte, writer io.Writer) (buf.Writer, error) {
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return buf.NewWriter(writer), nil
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}
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func (NoneCipher) EncodePacket(key []byte, b *buf.Buffer) error {
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return nil
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}
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func (NoneCipher) DecodePacket(key []byte, b *buf.Buffer) error {
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return nil
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}
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func passwordToCipherKey(password []byte, keySize int32) []byte {
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key := make([]byte, 0, keySize)
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md5Sum := md5.Sum(password)
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key = append(key, md5Sum[:]...)
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for int32(len(key)) < keySize {
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md5Hash := md5.New()
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common.Must2(md5Hash.Write(md5Sum[:]))
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common.Must2(md5Hash.Write(password))
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md5Hash.Sum(md5Sum[:0])
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key = append(key, md5Sum[:]...)
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}
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return key
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}
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func hkdfSHA1(secret, salt, outkey []byte) {
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r := hkdf.New(sha1.New, secret, salt, []byte("ss-subkey"))
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common.Must2(io.ReadFull(r, outkey))
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}
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