mirror of
https://github.com/XTLS/Xray-core.git
synced 2024-11-15 09:19:21 +02:00
350 lines
7.7 KiB
Go
350 lines
7.7 KiB
Go
package crypto
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import (
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"crypto/cipher"
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"crypto/rand"
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"io"
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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/bytespool"
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"github.com/xtls/xray-core/common/protocol"
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)
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type BytesGenerator func() []byte
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func GenerateEmptyBytes() BytesGenerator {
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var b [1]byte
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return func() []byte {
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return b[:0]
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}
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}
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func GenerateStaticBytes(content []byte) BytesGenerator {
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return func() []byte {
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return content
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}
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}
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func GenerateIncreasingNonce(nonce []byte) BytesGenerator {
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c := append([]byte(nil), nonce...)
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return func() []byte {
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for i := range c {
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c[i]++
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if c[i] != 0 {
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break
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}
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}
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return c
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}
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}
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func GenerateAEADNonceWithSize(nonceSize int) BytesGenerator {
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c := make([]byte, nonceSize)
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for i := 0; i < nonceSize; i++ {
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c[i] = 0xFF
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}
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return GenerateIncreasingNonce(c)
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}
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type Authenticator interface {
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NonceSize() int
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Overhead() int
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Open(dst, cipherText []byte) ([]byte, error)
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Seal(dst, plainText []byte) ([]byte, error)
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}
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type AEADAuthenticator struct {
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cipher.AEAD
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NonceGenerator BytesGenerator
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AdditionalDataGenerator BytesGenerator
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}
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func (v *AEADAuthenticator) Open(dst, cipherText []byte) ([]byte, error) {
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iv := v.NonceGenerator()
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if len(iv) != v.AEAD.NonceSize() {
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return nil, newError("invalid AEAD nonce size: ", len(iv))
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}
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var additionalData []byte
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if v.AdditionalDataGenerator != nil {
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additionalData = v.AdditionalDataGenerator()
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}
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return v.AEAD.Open(dst, iv, cipherText, additionalData)
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}
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func (v *AEADAuthenticator) Seal(dst, plainText []byte) ([]byte, error) {
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iv := v.NonceGenerator()
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if len(iv) != v.AEAD.NonceSize() {
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return nil, newError("invalid AEAD nonce size: ", len(iv))
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}
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var additionalData []byte
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if v.AdditionalDataGenerator != nil {
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additionalData = v.AdditionalDataGenerator()
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}
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return v.AEAD.Seal(dst, iv, plainText, additionalData), nil
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}
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type AuthenticationReader struct {
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auth Authenticator
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reader *buf.BufferedReader
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sizeParser ChunkSizeDecoder
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sizeBytes []byte
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transferType protocol.TransferType
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padding PaddingLengthGenerator
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size uint16
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paddingLen uint16
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hasSize bool
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done bool
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}
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func NewAuthenticationReader(auth Authenticator, sizeParser ChunkSizeDecoder, reader io.Reader, transferType protocol.TransferType, paddingLen PaddingLengthGenerator) *AuthenticationReader {
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r := &AuthenticationReader{
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auth: auth,
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sizeParser: sizeParser,
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transferType: transferType,
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padding: paddingLen,
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sizeBytes: make([]byte, sizeParser.SizeBytes()),
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}
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if breader, ok := reader.(*buf.BufferedReader); ok {
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r.reader = breader
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} else {
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r.reader = &buf.BufferedReader{Reader: buf.NewReader(reader)}
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}
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return r
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}
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func (r *AuthenticationReader) readSize() (uint16, uint16, error) {
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if r.hasSize {
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r.hasSize = false
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return r.size, r.paddingLen, nil
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}
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if _, err := io.ReadFull(r.reader, r.sizeBytes); err != nil {
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return 0, 0, err
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}
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var padding uint16
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if r.padding != nil {
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padding = r.padding.NextPaddingLen()
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}
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size, err := r.sizeParser.Decode(r.sizeBytes)
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return size, padding, err
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}
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var errSoft = newError("waiting for more data")
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func (r *AuthenticationReader) readBuffer(size int32, padding int32) (*buf.Buffer, error) {
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b := buf.New()
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if _, err := b.ReadFullFrom(r.reader, size); err != nil {
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b.Release()
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return nil, err
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}
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size -= padding
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rb, err := r.auth.Open(b.BytesTo(0), b.BytesTo(size))
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if err != nil {
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b.Release()
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return nil, err
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}
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b.Resize(0, int32(len(rb)))
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return b, nil
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}
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func (r *AuthenticationReader) readInternal(soft bool, mb *buf.MultiBuffer) error {
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if soft && r.reader.BufferedBytes() < r.sizeParser.SizeBytes() {
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return errSoft
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}
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if r.done {
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return io.EOF
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}
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size, padding, err := r.readSize()
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if err != nil {
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return err
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}
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if size == uint16(r.auth.Overhead())+padding {
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r.done = true
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return io.EOF
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}
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if soft && int32(size) > r.reader.BufferedBytes() {
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r.size = size
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r.paddingLen = padding
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r.hasSize = true
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return errSoft
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}
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if size <= buf.Size {
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b, err := r.readBuffer(int32(size), int32(padding))
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if err != nil {
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return nil
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}
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*mb = append(*mb, b)
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return nil
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}
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payload := bytespool.Alloc(int32(size))
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defer bytespool.Free(payload)
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if _, err := io.ReadFull(r.reader, payload[:size]); err != nil {
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return err
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}
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size -= padding
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rb, err := r.auth.Open(payload[:0], payload[:size])
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if err != nil {
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return err
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}
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*mb = buf.MergeBytes(*mb, rb)
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return nil
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}
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func (r *AuthenticationReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
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const readSize = 16
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mb := make(buf.MultiBuffer, 0, readSize)
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if err := r.readInternal(false, &mb); err != nil {
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buf.ReleaseMulti(mb)
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return nil, err
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}
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for i := 1; i < readSize; i++ {
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err := r.readInternal(true, &mb)
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if err == errSoft || err == io.EOF {
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break
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}
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if err != nil {
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buf.ReleaseMulti(mb)
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return nil, err
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}
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}
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return mb, nil
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}
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type AuthenticationWriter struct {
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auth Authenticator
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writer buf.Writer
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sizeParser ChunkSizeEncoder
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transferType protocol.TransferType
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padding PaddingLengthGenerator
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}
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func NewAuthenticationWriter(auth Authenticator, sizeParser ChunkSizeEncoder, writer io.Writer, transferType protocol.TransferType, padding PaddingLengthGenerator) *AuthenticationWriter {
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w := &AuthenticationWriter{
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auth: auth,
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writer: buf.NewWriter(writer),
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sizeParser: sizeParser,
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transferType: transferType,
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}
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if padding != nil {
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w.padding = padding
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}
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return w
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}
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func (w *AuthenticationWriter) seal(b []byte) (*buf.Buffer, error) {
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encryptedSize := int32(len(b) + w.auth.Overhead())
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var paddingSize int32
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if w.padding != nil {
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paddingSize = int32(w.padding.NextPaddingLen())
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}
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sizeBytes := w.sizeParser.SizeBytes()
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totalSize := sizeBytes + encryptedSize + paddingSize
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if totalSize > buf.Size {
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return nil, newError("size too large: ", totalSize)
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}
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eb := buf.New()
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w.sizeParser.Encode(uint16(encryptedSize+paddingSize), eb.Extend(sizeBytes))
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if _, err := w.auth.Seal(eb.Extend(encryptedSize)[:0], b); err != nil {
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eb.Release()
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return nil, err
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}
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if paddingSize > 0 {
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// These paddings will send in clear text.
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// To avoid leakage of PRNG internal state, a cryptographically secure PRNG should be used.
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paddingBytes := eb.Extend(paddingSize)
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common.Must2(rand.Read(paddingBytes))
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}
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return eb, nil
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}
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func (w *AuthenticationWriter) writeStream(mb buf.MultiBuffer) error {
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defer buf.ReleaseMulti(mb)
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var maxPadding int32
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if w.padding != nil {
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maxPadding = int32(w.padding.MaxPaddingLen())
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}
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payloadSize := buf.Size - int32(w.auth.Overhead()) - w.sizeParser.SizeBytes() - maxPadding
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mb2Write := make(buf.MultiBuffer, 0, len(mb)+10)
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temp := buf.New()
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defer temp.Release()
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rawBytes := temp.Extend(payloadSize)
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for {
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nb, nBytes := buf.SplitBytes(mb, rawBytes)
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mb = nb
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eb, err := w.seal(rawBytes[:nBytes])
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if err != nil {
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buf.ReleaseMulti(mb2Write)
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return err
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}
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mb2Write = append(mb2Write, eb)
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if mb.IsEmpty() {
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break
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}
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}
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return w.writer.WriteMultiBuffer(mb2Write)
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}
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func (w *AuthenticationWriter) writePacket(mb buf.MultiBuffer) error {
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defer buf.ReleaseMulti(mb)
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mb2Write := make(buf.MultiBuffer, 0, len(mb)+1)
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for _, b := range mb {
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if b.IsEmpty() {
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continue
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}
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eb, err := w.seal(b.Bytes())
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if err != nil {
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continue
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}
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mb2Write = append(mb2Write, eb)
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}
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if mb2Write.IsEmpty() {
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return nil
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}
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return w.writer.WriteMultiBuffer(mb2Write)
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}
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// WriteMultiBuffer implements buf.Writer.
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func (w *AuthenticationWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
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if mb.IsEmpty() {
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eb, err := w.seal([]byte{})
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common.Must(err)
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return w.writer.WriteMultiBuffer(buf.MultiBuffer{eb})
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}
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if w.transferType == protocol.TransferTypeStream {
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return w.writeStream(mb)
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}
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return w.writePacket(mb)
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}
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