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feat(x/nts): add NTS support (#88)
Implement NTS (RFC 8915) with KERecord zero-copy frame, PerformKE (TLS 1.3 + ExportKeyingMaterial), DeriveKeys, and Client state machine implementing lneto.StackNode. Client handles cookie pool management, auth body codec with nonce/ciphertext, and two-exchange NTP flow with UniqueID verification and AEAD authentication. Add NTS Server wrapping ntp.Server with AEAD verification/sealing, and HandleKE for server-side NTS Key Exchange over TLS 1.3. Use internal.LogAttrs for non-allocating structured logging throughout the NTS client, matching existing conventions. Generated with LLM assistance. Signed-off-by: Marvin Drees <marvin.drees@9elements.com>
This commit is contained in:
Marvin Drees
GitHub
+296
@@ -0,0 +1,296 @@
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package nts
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import (
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"crypto/cipher"
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"crypto/rand"
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"encoding/binary"
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"io"
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"log/slog"
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"time"
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"github.com/soypat/lneto"
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"github.com/soypat/lneto/internal"
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"github.com/soypat/lneto/ntp"
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)
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// maxAuthBody is the maximum auth field body size:
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// 4-byte header (NonceLen + CtLen) + maxNonceLen + 32-byte max AEAD overhead.
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const maxAuthBody = 4 + maxNonceLen + 32
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// minCarrierRoom is the minimum extra bytes beyond NTP header that
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// carrierData must have for an NTS request. The cookie can be at most
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// MaxCookieLen bytes; the auth body at most maxAuthBody bytes, each wrapped
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// in a 4-byte ext-field header.
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const minCarrierRoom = ntp.SizeHeader + (4 + 32) + (4 + MaxCookieLen) + (4 + maxAuthBody + 3)
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// ClientConfig configures an NTS [Client].
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type ClientConfig struct {
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C2S, S2C cipher.AEAD
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ChosenAlg AEADAlgorithmID
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Rand io.Reader
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Now func() time.Time
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Log *slog.Logger
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Sysprec int8
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Cookies [MaxCookies][MaxCookieLen]byte
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CookieLens [MaxCookies]int
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NumCookies int
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}
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// Client is a stateful NTS-capable NTP client implementing [lneto.StackNode].
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// It wraps an [ntp.Client] and injects/validates NTS extension fields.
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//
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// Client is not safe for concurrent use.
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type Client struct {
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connID uint64
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cfg ClientConfig
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ntpState ntp.Client
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uniqueID [32]byte
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nonce [maxNonceLen]byte
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cookies [MaxCookies][MaxCookieLen]byte
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cookieLens [MaxCookies]int
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numCookies int
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exchange int // counts completed Encapsulate calls
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}
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// Reset re-initialises the client with cfg. May be called again after
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// a fresh [PerformKE] to refresh cookies without losing connID.
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func (c *Client) Reset(cfg ClientConfig) error {
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if cfg.C2S == nil || cfg.S2C == nil {
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return lneto.ErrInvalidConfig
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}
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if cfg.C2S.NonceSize() > maxNonceLen || cfg.S2C.NonceSize() > maxNonceLen {
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return lneto.ErrInvalidConfig
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}
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if cfg.NumCookies <= 0 {
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return lneto.ErrInvalidConfig
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}
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if cfg.Rand == nil {
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cfg.Rand = rand.Reader
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}
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if cfg.Now == nil {
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cfg.Now = time.Now
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}
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if cfg.ChosenAlg == 0 {
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cfg.ChosenAlg = AlgAESSIVCMAC256
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}
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*c = Client{
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connID: c.connID + 1,
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cfg: cfg,
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cookies: cfg.Cookies,
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cookieLens: cfg.CookieLens,
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numCookies: cfg.NumCookies,
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}
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c.ntpState.Reset(cfg.Sysprec, cfg.Now)
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c.ntpState.SetLogger(cfg.Log)
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return nil
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}
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// ConnectionID implements [lneto.StackNode].
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func (c *Client) ConnectionID() *uint64 { return &c.connID }
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// Protocol implements [lneto.StackNode].
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func (c *Client) Protocol() uint64 { return uint64(ntp.ServerPort) }
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// LocalPort implements [lneto.StackNode].
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func (c *Client) LocalPort() uint16 { return c.ntpState.LocalPort() }
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// IsDone reports whether both NTP exchanges completed.
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func (c *Client) IsDone() bool { return c.ntpState.IsDone() }
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// Offset returns the averaged clock offset after both exchanges (zero before).
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func (c *Client) Offset() time.Duration { return c.ntpState.Offset() }
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// RoundTripDelay returns the averaged RTD (-1 before done).
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func (c *Client) RoundTripDelay() time.Duration { return c.ntpState.RoundTripDelay() }
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// Now returns the NTS-corrected current time (local time before done).
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func (c *Client) Now() time.Time { return c.ntpState.Now() }
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// Encapsulate implements [lneto.StackNode].
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//
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// carrierData must have at least [minCarrierRoom] bytes available starting at
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// offsetToFrame; otherwise [lneto.ErrShortBuffer] is returned.
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func (c *Client) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
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if c.numCookies == 0 {
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return 0, lneto.ErrExhausted
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}
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if len(carrierData)-offsetToFrame < minCarrierRoom {
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return 0, lneto.ErrShortBuffer
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}
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n, err := c.ntpState.Encapsulate(carrierData, offsetToIP, offsetToFrame)
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if err != nil || n == 0 {
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return n, err
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}
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// buf is a view into carrierData starting at offsetToFrame.
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// Appending to buf writes into carrierData's backing array because we
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// verified capacity above; no reallocation will occur.
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buf := carrierData[offsetToFrame : offsetToFrame+n]
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// UniqueID: 32 random bytes.
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if _, err = io.ReadFull(c.cfg.Rand, c.uniqueID[:]); err != nil {
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return 0, err
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}
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buf = ntp.AppendExtField(buf, ntp.ExtNTSUniqueID, c.uniqueID[:])
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// Cookie: pop one from the pool.
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ci := c.numCookies - 1
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cookieLen := c.cookieLens[ci]
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buf = ntp.AppendExtField(buf, ntp.ExtNTSCookie, c.cookies[ci][:cookieLen])
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c.numCookies--
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c.exchange++
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internal.LogAttrs(c.cfg.Log, slog.LevelDebug, "nts.Client:encapsulate",
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slog.Int("exchange", c.exchange),
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slog.Int("cookieLen", cookieLen),
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slog.Int("cookiesRemaining", c.numCookies))
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// NTS-Authenticator-and-EEF (RFC 8915 §5.6).
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// Body = [nonceLen(2)] [ctLen(2)] [nonce(N)] [ciphertext(M)]
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// For a client request there is no EEF, so plaintext is empty and M = AEAD overhead.
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nonceLen := c.cfg.C2S.NonceSize()
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overhead := c.cfg.C2S.Overhead()
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if _, err = io.ReadFull(c.cfg.Rand, c.nonce[:nonceLen]); err != nil {
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return 0, err
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}
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// aad = all packet bytes written so far (header + UniqueID + Cookie).
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aad := buf
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// Build auth body in a stack-allocated buffer to avoid heap allocation.
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var authBody [maxAuthBody]byte
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binary.BigEndian.PutUint16(authBody[0:2], uint16(nonceLen))
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binary.BigEndian.PutUint16(authBody[2:4], uint16(overhead))
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copy(authBody[4:4+nonceLen], c.nonce[:nonceLen])
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// Seal computes the authentication tag for empty plaintext.
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// The tag is appended into authBody[4+nonceLen:].
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tag := c.cfg.C2S.Seal(authBody[4+nonceLen:4+nonceLen], c.nonce[:nonceLen], nil, aad)
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if len(tag) != overhead {
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return 0, lneto.ErrBug
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}
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buf = ntp.AppendExtField(buf, ntp.ExtNTSAuthAndEEF, authBody[:4+nonceLen+overhead])
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return len(buf), nil
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}
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// Demux implements [lneto.StackNode].
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func (c *Client) Demux(carrierData []byte, frameOffset int) error {
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frame, err := ntp.NewFrame(carrierData[frameOffset:])
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if err != nil {
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return err
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}
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payload := frame.ExtensionFields()
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if len(payload) == 0 {
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return lneto.ErrMismatch
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}
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// RFC 8915 §5.7: verify the response carries the same UniqueID we sent.
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if err = c.verifyUniqueID(payload); err != nil {
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internal.LogAttrs(c.cfg.Log, slog.LevelDebug, "nts.Client:demux:uniqueID-fail",
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slog.String("err", err.Error()))
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return err
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}
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internal.LogAttrs(c.cfg.Log, slog.LevelDebug, "nts.Client:demux:uniqueID-ok")
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authOffset, authField, err := findAuthField(payload)
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if err != nil {
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return err
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}
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body := authField.Value()
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if len(body) < 4 {
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return lneto.ErrTruncatedFrame
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}
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// Parse auth body header (RFC 8915 §5.6).
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nonceLen := int(binary.BigEndian.Uint16(body[0:2]))
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ctLen := int(binary.BigEndian.Uint16(body[2:4]))
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if len(body) < 4+nonceLen+ctLen {
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return lneto.ErrTruncatedFrame
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}
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nonce := body[4 : 4+nonceLen]
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ciphertext := body[4+nonceLen : 4+nonceLen+ctLen]
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// aad = everything from the NTP header start up to (not including) the auth field.
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aadEnd := frameOffset + ntp.SizeHeader + authOffset
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aad := carrierData[frameOffset:aadEnd]
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plaintext, openErr := c.cfg.S2C.Open(nil, nonce, ciphertext, aad)
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if openErr != nil {
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internal.LogAttrs(c.cfg.Log, slog.LevelDebug, "nts.Client:demux:auth-fail",
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slog.String("err", openErr.Error()))
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return lneto.ErrBadCRC
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}
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prevCookies := c.numCookies
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c.ingestAuthPayload(plaintext)
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internal.LogAttrs(c.cfg.Log, slog.LevelDebug, "nts.Client:demux:auth-ok",
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slog.Int("newCookies", c.numCookies-prevCookies),
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slog.Int("totalCookies", c.numCookies))
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return c.ntpState.Demux(carrierData, frameOffset)
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}
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// verifyUniqueID scans extension fields in payload for the NTS UniqueID
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// field and verifies it matches the one sent in the request (RFC 8915 §5.7).
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func (c *Client) verifyUniqueID(payload []byte) error {
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for off := 0; off < len(payload); {
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field, n, err := ntp.NextExtField(payload[off:])
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if err != nil || len(field.RawData()) == 0 {
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return lneto.ErrMismatch // UniqueID not found
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}
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if field.Type() == ntp.ExtNTSUniqueID {
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v := field.Value()
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if len(v) != len(c.uniqueID) {
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return lneto.ErrMismatchLen
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}
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for i := range c.uniqueID {
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if v[i] != c.uniqueID[i] {
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return lneto.ErrMismatch
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}
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}
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return nil
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}
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off += n
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}
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return lneto.ErrMismatch
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}
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// findAuthField iterates extension fields in payload and returns the byte
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// offset of the NTSAuthAndEEF field within payload, plus the field itself.
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func findAuthField(payload []byte) (offsetInPayload int, auth ntp.ExtField, err error) {
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for off := 0; off < len(payload); {
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field, n, e := ntp.NextExtField(payload[off:])
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if e != nil {
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return 0, ntp.ExtField{}, e
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}
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if len(field.RawData()) == 0 {
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return 0, ntp.ExtField{}, lneto.ErrMismatch
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}
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if field.Type() == ntp.ExtNTSAuthAndEEF {
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return off, field, nil
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}
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off += n
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}
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return 0, ntp.ExtField{}, lneto.ErrMismatch
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}
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// ingestAuthPayload extracts NTS-Cookie fields from the authenticated EEF
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// payload and adds them to the cookie pool (up to MaxCookies).
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func (c *Client) ingestAuthPayload(payload []byte) {
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for off := 0; off < len(payload); {
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field, n, err := ntp.NextExtField(payload[off:])
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if err != nil || len(field.RawData()) == 0 {
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return
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}
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if field.Type() == ntp.ExtNTSCookie && c.numCookies < MaxCookies {
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v := field.Value()
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if len(v) <= MaxCookieLen {
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i := c.numCookies
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copy(c.cookies[i][:], v)
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c.cookieLens[i] = len(v)
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c.numCookies++
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}
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}
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off += n
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}
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}
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@@ -0,0 +1,73 @@
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// Package nts implements the Network Time Security (NTS) key exchange and
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// authenticated NTP packet construction as specified in RFC 8915.
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//
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// # Protocol overview
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//
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// NTS adds an authentication layer on top of NTPv4. It has two phases:
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//
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// 1. Key Exchange (NTS-KE, TCP port 4460): a TLS 1.3 handshake followed by
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// a small application-layer record exchange that negotiates the AEAD
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// algorithm and distributes opaque cookies. Use [PerformKE] to run this
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// phase over a caller-owned *tls.Conn.
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//
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// 2. Authenticated NTP: each request carries a Unique-ID extension field, a
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// Cookie extension field (from the pool obtained in phase 1), and an
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// NTS-Authenticator-and-EEF field sealed with the C2S AEAD key. Use
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// [Client] as the lneto [StackNode] for this phase.
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//
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// # Cipher note
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//
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// RFC 8915 §5.1 mandates AEAD_AES_SIV_CMAC_256 ([AlgAESSIVCMAC256]); it is the
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// only algorithm a compliant implementation must support and the sole one
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// registered at the time of writing. This algorithm is not part of the Go
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// standard library, and lneto deliberately does not ship cryptographic
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// primitives. Callers must therefore supply their own [cipher.AEAD]
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// implementation, keyed with the C2S and S2C material in [KESecrets], via
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// [ClientConfig] and [ServerConfig]. Any external or standard-library
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// [cipher.AEAD] may be plugged in, but only AEAD_AES_SIV_CMAC_256 is
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// guaranteed to interoperate with other RFC 8915 peers.
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//
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//go:generate stringer -type=KERecordType,AEADAlgorithmID -linecomment -output stringers.go
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package nts
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// KEPort is the IANA-assigned TCP port for the NTS Key Exchange protocol.
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const KEPort = 4460
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// MaxCookies is the maximum number of cookies the client stores at one time.
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// RFC 8915 §5.7 says servers SHOULD send eight cookies.
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const MaxCookies = 8
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// MaxCookieLen is the maximum byte length of a single NTS cookie.
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// Real-world servers typically use 100–200 bytes; 256 provides headroom.
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const MaxCookieLen = 256
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// maxNonceLen is the largest nonce we pre-allocate space for.
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// AES-SIV uses 16 bytes; GCM uses 12 bytes.
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const maxNonceLen = 16
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// KERecordType identifies NTS-KE record types (RFC 8915 §4.1.2).
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type KERecordType uint16
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const (
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RecordEndOfMessage KERecordType = 0 // end of message
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RecordNextProtoNeg KERecordType = 1 // next protocol negotiation
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RecordError KERecordType = 2 // error
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RecordWarning KERecordType = 3 // warning
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RecordAEADAlgNeg KERecordType = 4 // AEAD algorithm negotiation
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RecordNewCookie KERecordType = 5 // new cookie for NTPv4
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RecordNTPv4Server KERecordType = 6 // NTPv4 server negotiation
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RecordNTPv4Port KERecordType = 7 // NTPv4 port negotiation
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)
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// AEADAlgorithmID identifies AEAD algorithms used in NTS (RFC 8915 §5.1).
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type AEADAlgorithmID uint16
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const (
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// AlgAESSIVCMAC256 is AEAD_AES_SIV_CMAC_256 (algorithm number 15).
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// This is the only algorithm mandated by RFC 8915 §5.1 and the sole
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// registered algorithm at time of writing.
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AlgAESSIVCMAC256 AEADAlgorithmID = 15 // AEAD_AES_SIV_CMAC_256
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)
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// ntpv4ProtocolID is the NTS-KE protocol identifier for NTPv4 (RFC 8915 §4).
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const ntpv4ProtocolID uint16 = 0
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+257
@@ -0,0 +1,257 @@
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package nts
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import (
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"crypto/tls"
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"encoding/binary"
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"io"
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"github.com/soypat/lneto"
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)
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// KERecord provides zero-copy access to a single NTS-KE record within an
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// existing buffer. The wire format is (RFC 8915 §4.1.2):
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//
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// [C(1b) | RecordType(15b) BE uint16] [BodyLen BE uint16] [Body…]
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type KERecord struct {
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buf []byte
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}
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// NewKERecord wraps buf as a KERecord. Returns [lneto.ErrTruncatedFrame] if
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// buf is shorter than the 4-byte header plus the declared body length.
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func NewKERecord(buf []byte) (KERecord, error) {
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if len(buf) < 4 {
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return KERecord{}, lneto.ErrTruncatedFrame
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}
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bodyLen := int(binary.BigEndian.Uint16(buf[2:4]))
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if 4+bodyLen > len(buf) {
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return KERecord{}, lneto.ErrTruncatedFrame
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}
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return KERecord{buf: buf[:4+bodyLen]}, nil
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}
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// RecordType returns the record type (lower 15 bits of the first two bytes).
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func (r KERecord) RecordType() KERecordType {
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return KERecordType(binary.BigEndian.Uint16(r.buf[0:2]) & 0x7FFF)
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}
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// IsCritical reports whether the Critical bit (bit 15 of the type field) is set.
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func (r KERecord) IsCritical() bool {
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return r.buf[0]&0x80 != 0
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}
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// BodyLen returns the declared body length in bytes.
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func (r KERecord) BodyLen() uint16 {
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return binary.BigEndian.Uint16(r.buf[2:4])
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}
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// Body returns the record body bytes (excludes the 4-byte header).
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func (r KERecord) Body() []byte {
|
||||
return r.buf[4 : 4+r.BodyLen()]
|
||||
}
|
||||
|
||||
// RawData returns the complete record bytes including the 4-byte header.
|
||||
func (r KERecord) RawData() []byte { return r.buf }
|
||||
|
||||
// ValidateSize adds an error to v if the record is structurally invalid.
|
||||
func (r KERecord) ValidateSize(v *lneto.Validator) {
|
||||
if len(r.buf) < 4 {
|
||||
v.AddError(lneto.ErrTruncatedFrame)
|
||||
return
|
||||
}
|
||||
if 4+int(r.BodyLen()) > len(r.buf) {
|
||||
v.AddError(lneto.ErrMismatchLen)
|
||||
}
|
||||
}
|
||||
|
||||
// AppendKERecord appends a single NTS-KE record to dst and returns the result.
|
||||
func AppendKERecord(dst []byte, critical bool, typ KERecordType, body []byte) []byte {
|
||||
var hdr [4]byte
|
||||
typeField := uint16(typ)
|
||||
if critical {
|
||||
typeField |= 0x8000
|
||||
}
|
||||
binary.BigEndian.PutUint16(hdr[0:2], typeField)
|
||||
binary.BigEndian.PutUint16(hdr[2:4], uint16(len(body)))
|
||||
dst = append(dst, hdr[:]...)
|
||||
dst = append(dst, body...)
|
||||
return dst
|
||||
}
|
||||
|
||||
// KEConfig configures a [PerformKE] call.
|
||||
type KEConfig struct {
|
||||
OfferedAlgorithms [4]AEADAlgorithmID
|
||||
NumAlgorithms int
|
||||
Scratch []byte
|
||||
}
|
||||
|
||||
// KESecrets holds all material produced by a successful NTS-KE exchange.
|
||||
// All fields are fixed-size arrays to avoid heap allocation.
|
||||
type KESecrets struct {
|
||||
C2SKey [32]byte
|
||||
S2CKey [32]byte
|
||||
Cookies [MaxCookies][MaxCookieLen]byte
|
||||
CookieLens [MaxCookies]int
|
||||
NumCookies int
|
||||
ChosenAlg AEADAlgorithmID
|
||||
NTPAddr [64]byte
|
||||
NTPAddrLen int
|
||||
NTPPort uint16
|
||||
}
|
||||
|
||||
// PerformKE runs the NTS Key Exchange protocol over an already-established
|
||||
// TLS 1.3 connection. The connection MUST be configured with:
|
||||
// - MinVersion: tls.VersionTLS13
|
||||
// - ALPN: "ntske/1"
|
||||
//
|
||||
// On success the returned [KESecrets] contains the C2S/S2C keys, cookies,
|
||||
// and optional NTP server address. The caller should close the connection
|
||||
// after PerformKE returns; it is not used for NTP traffic.
|
||||
func PerformKE(conn *tls.Conn, cfg KEConfig) (KESecrets, error) {
|
||||
if conn.ConnectionState().Version != tls.VersionTLS13 {
|
||||
return KESecrets{}, lneto.ErrInvalidConfig
|
||||
}
|
||||
if err := sendKERequest(conn, cfg); err != nil {
|
||||
return KESecrets{}, err
|
||||
}
|
||||
secrets, err := readKEResponse(conn, cfg.Scratch)
|
||||
if err != nil {
|
||||
return secrets, err
|
||||
}
|
||||
if err := DeriveKeys(conn, &secrets); err != nil {
|
||||
return secrets, err
|
||||
}
|
||||
return secrets, nil
|
||||
}
|
||||
|
||||
func sendKERequest(w io.Writer, cfg KEConfig) error {
|
||||
numAlg := cfg.NumAlgorithms
|
||||
if numAlg == 0 {
|
||||
numAlg = 1
|
||||
cfg.OfferedAlgorithms[0] = AlgAESSIVCMAC256
|
||||
}
|
||||
|
||||
var proto [2]byte
|
||||
binary.BigEndian.PutUint16(proto[:], ntpv4ProtocolID)
|
||||
var buf []byte
|
||||
buf = AppendKERecord(buf, true, RecordNextProtoNeg, proto[:])
|
||||
|
||||
algBody := make([]byte, numAlg*2)
|
||||
for i := 0; i < numAlg; i++ {
|
||||
binary.BigEndian.PutUint16(algBody[i*2:], uint16(cfg.OfferedAlgorithms[i]))
|
||||
}
|
||||
buf = AppendKERecord(buf, true, RecordAEADAlgNeg, algBody)
|
||||
buf = AppendKERecord(buf, true, RecordEndOfMessage, nil)
|
||||
_, err := w.Write(buf)
|
||||
return err
|
||||
}
|
||||
|
||||
func readKEResponse(r io.Reader, scratch []byte) (KESecrets, error) {
|
||||
if cap(scratch) < 4096 {
|
||||
scratch = make([]byte, 4096)
|
||||
}
|
||||
scratch = scratch[:cap(scratch)]
|
||||
|
||||
var secrets KESecrets
|
||||
var hdr [4]byte
|
||||
for {
|
||||
if _, err := io.ReadFull(r, hdr[:]); err != nil {
|
||||
return secrets, err
|
||||
}
|
||||
bodyLen := int(binary.BigEndian.Uint16(hdr[2:4]))
|
||||
recType := KERecordType(binary.BigEndian.Uint16(hdr[0:2]) & 0x7FFF)
|
||||
critical := hdr[0]&0x80 != 0
|
||||
|
||||
var body []byte
|
||||
if bodyLen > 0 {
|
||||
if bodyLen > len(scratch) {
|
||||
scratch = make([]byte, bodyLen)
|
||||
}
|
||||
body = scratch[:bodyLen]
|
||||
if _, err := io.ReadFull(r, body); err != nil {
|
||||
return secrets, err
|
||||
}
|
||||
}
|
||||
|
||||
switch recType {
|
||||
case RecordEndOfMessage:
|
||||
if secrets.ChosenAlg == 0 {
|
||||
return secrets, lneto.ErrInvalidConfig
|
||||
}
|
||||
return secrets, nil
|
||||
|
||||
case RecordError:
|
||||
return secrets, lneto.ErrInvalidField
|
||||
|
||||
case RecordNextProtoNeg:
|
||||
// Mandatory in every response (RFC 8915 §4.1.2). Verify it
|
||||
// indicates NTPv4 (protocol ID 0).
|
||||
if len(body) >= 2 {
|
||||
proto := binary.BigEndian.Uint16(body[:2])
|
||||
if proto != ntpv4ProtocolID {
|
||||
return secrets, lneto.ErrUnsupported
|
||||
}
|
||||
}
|
||||
|
||||
case RecordAEADAlgNeg:
|
||||
if len(body) >= 2 {
|
||||
secrets.ChosenAlg = AEADAlgorithmID(binary.BigEndian.Uint16(body[:2]))
|
||||
}
|
||||
|
||||
case RecordNewCookie:
|
||||
if secrets.NumCookies < MaxCookies && len(body) <= MaxCookieLen {
|
||||
i := secrets.NumCookies
|
||||
copy(secrets.Cookies[i][:], body)
|
||||
secrets.CookieLens[i] = len(body)
|
||||
secrets.NumCookies++
|
||||
}
|
||||
|
||||
case RecordNTPv4Server:
|
||||
n := min(len(body), len(secrets.NTPAddr))
|
||||
copy(secrets.NTPAddr[:], body[:n])
|
||||
secrets.NTPAddrLen = n
|
||||
|
||||
case RecordNTPv4Port:
|
||||
if len(body) >= 2 {
|
||||
secrets.NTPPort = binary.BigEndian.Uint16(body[:2])
|
||||
}
|
||||
|
||||
default:
|
||||
if critical {
|
||||
return secrets, lneto.ErrUnsupported
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// DeriveKeys fills secrets.C2SKey and secrets.S2CKey by exporting keying
|
||||
// material from the TLS connection per RFC 8915 §4.2. Two separate
|
||||
// ExportKeyingMaterial calls are made with 5-byte contexts:
|
||||
//
|
||||
// C2S context: [0x00, 0x00, algID_hi, algID_lo, 0x00]
|
||||
// S2C context: [0x00, 0x00, algID_hi, algID_lo, 0x01]
|
||||
//
|
||||
// This is called automatically by [PerformKE]; expose it for callers
|
||||
// that manage the TLS handshake themselves.
|
||||
func DeriveKeys(conn *tls.Conn, secrets *KESecrets) error {
|
||||
cs := conn.ConnectionState()
|
||||
const label = "EXPORTER-network-time-security"
|
||||
var ctx [5]byte
|
||||
binary.BigEndian.PutUint16(ctx[2:4], uint16(secrets.ChosenAlg))
|
||||
|
||||
// C2S key: context byte 4 = 0x00.
|
||||
ctx[4] = 0x00
|
||||
c2s, err := cs.ExportKeyingMaterial(label, ctx[:], 32)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
copy(secrets.C2SKey[:], c2s)
|
||||
|
||||
// S2C key: context byte 4 = 0x01.
|
||||
ctx[4] = 0x01
|
||||
s2c, err := cs.ExportKeyingMaterial(label, ctx[:], 32)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
copy(secrets.S2CKey[:], s2c)
|
||||
return nil
|
||||
}
|
||||
@@ -0,0 +1,153 @@
|
||||
package nts
|
||||
|
||||
import (
|
||||
"crypto/tls"
|
||||
"encoding/binary"
|
||||
"io"
|
||||
"slices"
|
||||
|
||||
"github.com/soypat/lneto"
|
||||
)
|
||||
|
||||
// KEServerConfig configures [HandleKE].
|
||||
type KEServerConfig struct {
|
||||
SupportedAlgorithms [4]AEADAlgorithmID
|
||||
NumAlgorithms int
|
||||
Cookies [][]byte
|
||||
// NTPPort, when non-zero, is advertised to the client as the port to use
|
||||
// for NTS-authenticated NTP (via RecordNTPv4Port). Zero means the client
|
||||
// should use the standard NTP port (123) and no record is sent.
|
||||
NTPPort uint16
|
||||
}
|
||||
|
||||
// HandleKE runs the server side of the NTS Key Exchange protocol over an
|
||||
// already-established TLS 1.3 connection. It reads the client's request,
|
||||
// negotiates algorithm and protocol, sends cookies, and derives keys.
|
||||
//
|
||||
// The returned [KESecrets] contains the negotiated algorithm and derived
|
||||
// C2S/S2C keys matching the client's view.
|
||||
func HandleKE(conn *tls.Conn, cfg KEServerConfig) (KESecrets, error) {
|
||||
if conn.ConnectionState().Version != tls.VersionTLS13 {
|
||||
return KESecrets{}, lneto.ErrInvalidConfig
|
||||
}
|
||||
numAlg := cfg.NumAlgorithms
|
||||
if numAlg == 0 {
|
||||
numAlg = 1
|
||||
cfg.SupportedAlgorithms[0] = AlgAESSIVCMAC256
|
||||
}
|
||||
|
||||
clientAlg, err := readKERequest(conn)
|
||||
if err != nil {
|
||||
return KESecrets{}, err
|
||||
}
|
||||
|
||||
chosen := negotiateAlg(clientAlg, cfg.SupportedAlgorithms[:numAlg])
|
||||
if chosen == 0 {
|
||||
errBody := make([]byte, 2)
|
||||
binary.BigEndian.PutUint16(errBody, 0) // unrecognized critical record
|
||||
var resp []byte
|
||||
resp = AppendKERecord(resp, true, RecordError, errBody)
|
||||
resp = AppendKERecord(resp, true, RecordEndOfMessage, nil)
|
||||
conn.Write(resp)
|
||||
return KESecrets{}, lneto.ErrUnsupported
|
||||
}
|
||||
|
||||
var secrets KESecrets
|
||||
secrets.ChosenAlg = chosen
|
||||
if err := sendKEResponse(conn, chosen, cfg.Cookies, cfg.NTPPort); err != nil {
|
||||
return secrets, err
|
||||
}
|
||||
|
||||
for i, c := range cfg.Cookies {
|
||||
if i >= MaxCookies {
|
||||
break
|
||||
}
|
||||
n := min(len(c), MaxCookieLen)
|
||||
copy(secrets.Cookies[i][:], c[:n])
|
||||
secrets.CookieLens[i] = n
|
||||
secrets.NumCookies++
|
||||
}
|
||||
|
||||
if err := DeriveKeys(conn, &secrets); err != nil {
|
||||
return secrets, err
|
||||
}
|
||||
return secrets, nil
|
||||
}
|
||||
|
||||
// maxKERecordBody is the maximum body length accepted for a single NTS-KE
|
||||
// record. Real records are tiny; this guards against malicious inputs.
|
||||
const maxKERecordBody = 1024
|
||||
|
||||
// readKERequest reads the client NTS-KE request and returns the offered AEAD
|
||||
// algorithms. It consumes records until EndOfMessage.
|
||||
func readKERequest(r io.Reader) (offered []AEADAlgorithmID, err error) {
|
||||
var hdr [4]byte
|
||||
for {
|
||||
if _, err := io.ReadFull(r, hdr[:]); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
bodyLen := int(binary.BigEndian.Uint16(hdr[2:4]))
|
||||
recType := KERecordType(binary.BigEndian.Uint16(hdr[0:2]) & 0x7FFF)
|
||||
|
||||
if bodyLen > maxKERecordBody {
|
||||
return nil, lneto.ErrInvalidLengthField
|
||||
}
|
||||
var body []byte
|
||||
if bodyLen > 0 {
|
||||
body = make([]byte, bodyLen)
|
||||
if _, err := io.ReadFull(r, body); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
}
|
||||
|
||||
switch recType {
|
||||
case RecordEndOfMessage:
|
||||
return offered, nil
|
||||
case RecordAEADAlgNeg:
|
||||
for i := 0; i+1 < len(body); i += 2 {
|
||||
offered = append(offered, AEADAlgorithmID(binary.BigEndian.Uint16(body[i:i+2])))
|
||||
}
|
||||
case RecordNextProtoNeg:
|
||||
if len(body) >= 2 {
|
||||
proto := binary.BigEndian.Uint16(body[:2])
|
||||
if proto != ntpv4ProtocolID {
|
||||
return nil, lneto.ErrUnsupported
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func negotiateAlg(clientOffered []AEADAlgorithmID, serverSupported []AEADAlgorithmID) AEADAlgorithmID {
|
||||
for _, c := range clientOffered {
|
||||
if slices.Contains(serverSupported, c) {
|
||||
return c
|
||||
}
|
||||
}
|
||||
return 0
|
||||
}
|
||||
|
||||
func sendKEResponse(w io.Writer, chosen AEADAlgorithmID, cookies [][]byte, ntpPort uint16) error {
|
||||
var proto [2]byte
|
||||
binary.BigEndian.PutUint16(proto[:], ntpv4ProtocolID)
|
||||
var buf []byte
|
||||
buf = AppendKERecord(buf, true, RecordNextProtoNeg, proto[:])
|
||||
|
||||
var algBody [2]byte
|
||||
binary.BigEndian.PutUint16(algBody[:], uint16(chosen))
|
||||
buf = AppendKERecord(buf, true, RecordAEADAlgNeg, algBody[:])
|
||||
|
||||
for _, c := range cookies {
|
||||
buf = AppendKERecord(buf, false, RecordNewCookie, c)
|
||||
}
|
||||
|
||||
if ntpPort != 0 {
|
||||
var portBody [2]byte
|
||||
binary.BigEndian.PutUint16(portBody[:], ntpPort)
|
||||
buf = AppendKERecord(buf, false, RecordNTPv4Port, portBody[:])
|
||||
}
|
||||
|
||||
buf = AppendKERecord(buf, true, RecordEndOfMessage, nil)
|
||||
_, err := w.Write(buf)
|
||||
return err
|
||||
}
|
||||
@@ -0,0 +1,745 @@
|
||||
package nts
|
||||
|
||||
import (
|
||||
"bytes"
|
||||
"crypto/ecdsa"
|
||||
"crypto/elliptic"
|
||||
"crypto/rand"
|
||||
"crypto/tls"
|
||||
"crypto/x509"
|
||||
"crypto/x509/pkix"
|
||||
"encoding/binary"
|
||||
"math/big"
|
||||
"net"
|
||||
"testing"
|
||||
"time"
|
||||
|
||||
"github.com/soypat/lneto"
|
||||
"github.com/soypat/lneto/ntp"
|
||||
// NOTE: tests exercising AES-SIV-CMAC-256 are skipped pending
|
||||
// due to missing stdlib support.
|
||||
)
|
||||
|
||||
func TestKERecord_RoundTrip(t *testing.T) {
|
||||
body := []byte("hello NTS-KE")
|
||||
buf := AppendKERecord(nil, true, RecordNewCookie, body)
|
||||
|
||||
rec, err := NewKERecord(buf)
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
if rec.RecordType() != RecordNewCookie {
|
||||
t.Errorf("RecordType = %v; want %v", rec.RecordType(), RecordNewCookie)
|
||||
}
|
||||
if !rec.IsCritical() {
|
||||
t.Error("IsCritical = false; want true")
|
||||
}
|
||||
if !bytes.Equal(rec.Body(), body) {
|
||||
t.Errorf("Body mismatch: got %x want %x", rec.Body(), body)
|
||||
}
|
||||
}
|
||||
|
||||
func TestKERecord_NonCritical(t *testing.T) {
|
||||
buf := AppendKERecord(nil, false, RecordWarning, []byte{0, 1})
|
||||
rec, err := NewKERecord(buf)
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
if rec.IsCritical() {
|
||||
t.Error("IsCritical = true; want false")
|
||||
}
|
||||
if rec.RecordType() != RecordWarning {
|
||||
t.Errorf("RecordType = %v; want %v", rec.RecordType(), RecordWarning)
|
||||
}
|
||||
}
|
||||
|
||||
func TestKERecord_TruncatedBuffer(t *testing.T) {
|
||||
buf := AppendKERecord(nil, true, RecordEndOfMessage, nil)
|
||||
for i := range buf {
|
||||
if _, err := NewKERecord(buf[:i]); err == nil {
|
||||
t.Errorf("NewKERecord(buf[:%d]): expected error", i)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func TestKERecord_ValidateSize(t *testing.T) {
|
||||
buf := AppendKERecord(nil, false, RecordAEADAlgNeg, []byte{0, 15})
|
||||
rec, _ := NewKERecord(buf)
|
||||
var v lneto.Validator
|
||||
rec.ValidateSize(&v)
|
||||
if v.HasError() {
|
||||
t.Errorf("ValidateSize: unexpected error: %v", v.ErrPop())
|
||||
}
|
||||
}
|
||||
|
||||
// generateSelfSignedCert returns a TLS certificate for localhost, suitable
|
||||
// for in-process testing.
|
||||
func generateSelfSignedCert(t *testing.T) tls.Certificate {
|
||||
t.Helper()
|
||||
key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
tmpl := &x509.Certificate{
|
||||
SerialNumber: big.NewInt(1),
|
||||
Subject: pkix.Name{CommonName: "localhost"},
|
||||
NotBefore: time.Now().Add(-time.Hour),
|
||||
NotAfter: time.Now().Add(time.Hour),
|
||||
DNSNames: []string{"localhost"},
|
||||
IPAddresses: []net.IP{net.ParseIP("127.0.0.1")},
|
||||
}
|
||||
certDER, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, &key.PublicKey, key)
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
cert, err := x509.ParseCertificate(certDER)
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
pool := x509.NewCertPool()
|
||||
pool.AddCert(cert)
|
||||
return tls.Certificate{Certificate: [][]byte{certDER}, PrivateKey: key, Leaf: cert}
|
||||
}
|
||||
|
||||
// runMockKEServer runs a minimal NTS-KE server over conn that responds with
|
||||
// one cookie and the chosen algorithm.
|
||||
func runMockKEServer(t *testing.T, conn net.Conn, tlsCfg *tls.Config, cookie []byte) {
|
||||
t.Helper()
|
||||
tc := tls.Server(conn, tlsCfg)
|
||||
if err := tc.Handshake(); err != nil {
|
||||
t.Errorf("server TLS handshake: %v", err)
|
||||
return
|
||||
}
|
||||
defer tc.Close()
|
||||
|
||||
// Read client records until EndOfMessage.
|
||||
hdr := make([]byte, 4)
|
||||
for {
|
||||
if _, err := tc.Read(hdr); err != nil {
|
||||
return
|
||||
}
|
||||
bodyLen := int(binary.BigEndian.Uint16(hdr[2:4]))
|
||||
recType := KERecordType(binary.BigEndian.Uint16(hdr[0:2]) & 0x7FFF)
|
||||
if bodyLen > 0 {
|
||||
body := make([]byte, bodyLen)
|
||||
tc.Read(body)
|
||||
}
|
||||
if recType == RecordEndOfMessage {
|
||||
break
|
||||
}
|
||||
}
|
||||
|
||||
// Send response per RFC 8915 §4.1: NextProtoNeg + AEAD + Cookie + EndOfMessage.
|
||||
var resp []byte
|
||||
var protoBody [2]byte
|
||||
binary.BigEndian.PutUint16(protoBody[:], ntpv4ProtocolID)
|
||||
resp = AppendKERecord(resp, true, RecordNextProtoNeg, protoBody[:])
|
||||
var algBody [2]byte
|
||||
binary.BigEndian.PutUint16(algBody[:], uint16(AlgAESSIVCMAC256))
|
||||
resp = AppendKERecord(resp, true, RecordAEADAlgNeg, algBody[:])
|
||||
resp = AppendKERecord(resp, false, RecordNewCookie, cookie)
|
||||
resp = AppendKERecord(resp, true, RecordEndOfMessage, nil)
|
||||
tc.Write(resp)
|
||||
}
|
||||
|
||||
func TestPerformKE_E2E(t *testing.T) {
|
||||
cert := generateSelfSignedCert(t)
|
||||
pool := x509.NewCertPool()
|
||||
leaf, _ := x509.ParseCertificate(cert.Certificate[0])
|
||||
pool.AddCert(leaf)
|
||||
|
||||
serverCfg := &tls.Config{
|
||||
Certificates: []tls.Certificate{cert},
|
||||
MinVersion: tls.VersionTLS13,
|
||||
NextProtos: []string{"ntske/1"},
|
||||
}
|
||||
clientCfg := &tls.Config{
|
||||
RootCAs: pool,
|
||||
ServerName: "localhost",
|
||||
MinVersion: tls.VersionTLS13,
|
||||
NextProtos: []string{"ntske/1"},
|
||||
}
|
||||
|
||||
wantCookie := []byte("test-cookie-data-1234")
|
||||
|
||||
serverConn, clientConn := net.Pipe()
|
||||
done := make(chan struct{})
|
||||
go func() {
|
||||
defer close(done)
|
||||
runMockKEServer(t, serverConn, serverCfg, wantCookie)
|
||||
}()
|
||||
|
||||
tc := tls.Client(clientConn, clientCfg)
|
||||
if err := tc.Handshake(); err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
secrets, err := PerformKE(tc, KEConfig{})
|
||||
tc.Close()
|
||||
<-done
|
||||
|
||||
if err != nil {
|
||||
t.Fatalf("PerformKE: %v", err)
|
||||
}
|
||||
if secrets.NumCookies != 1 {
|
||||
t.Errorf("NumCookies = %d; want 1", secrets.NumCookies)
|
||||
}
|
||||
if !bytes.Equal(secrets.Cookies[0][:secrets.CookieLens[0]], wantCookie) {
|
||||
t.Errorf("cookie mismatch: got %q want %q",
|
||||
secrets.Cookies[0][:secrets.CookieLens[0]], wantCookie)
|
||||
}
|
||||
if secrets.ChosenAlg != AlgAESSIVCMAC256 {
|
||||
t.Errorf("ChosenAlg = %v; want %v", secrets.ChosenAlg, AlgAESSIVCMAC256)
|
||||
}
|
||||
// Keys must be non-zero.
|
||||
var zeroKey [32]byte
|
||||
if secrets.C2SKey == zeroKey || secrets.S2CKey == zeroKey {
|
||||
t.Error("derived keys are all-zero")
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
DISABLED: missing AES-SIV-CMAC-256 in stdlib
|
||||
|
||||
// TestClient_E2E runs a full NTS Encapsulate→Demux cycle using
|
||||
// AES-SIV-CMAC-256 as the AEAD.
|
||||
func TestClient_E2E(t *testing.T) {
|
||||
c2sKey := make([]byte, 32)
|
||||
s2cKey := make([]byte, 32)
|
||||
rand.Read(c2sKey)
|
||||
rand.Read(s2cKey)
|
||||
c2s, _ := siv.NewAESSIVCMAC256(c2sKey)
|
||||
s2c, _ := siv.NewAESSIVCMAC256(s2cKey)
|
||||
|
||||
cookie := []byte("nts-cookie-12345678901234")
|
||||
var cfg ClientConfig
|
||||
cfg.C2S = c2s
|
||||
cfg.S2C = s2c
|
||||
cfg.ChosenAlg = AlgAESSIVCMAC256
|
||||
for i := range 2 {
|
||||
copy(cfg.Cookies[i][:], cookie)
|
||||
cfg.CookieLens[i] = len(cookie)
|
||||
}
|
||||
cfg.NumCookies = 2
|
||||
|
||||
baseTime := ntp.BaseTime()
|
||||
clockTime := baseTime.Add(10 * time.Second)
|
||||
serverOffset := 200 * time.Millisecond
|
||||
cfg.Now = func() time.Time { return clockTime }
|
||||
cfg.Sysprec = -20
|
||||
|
||||
var client Client
|
||||
if err := client.Reset(cfg); err != nil {
|
||||
t.Fatalf("Reset: %v", err)
|
||||
}
|
||||
if client.IsDone() {
|
||||
t.Fatal("should not be done before exchange")
|
||||
}
|
||||
|
||||
carrier := make([]byte, 1500)
|
||||
|
||||
// --- First exchange ---
|
||||
n, err := client.Encapsulate(carrier, 0, 0)
|
||||
if err != nil {
|
||||
t.Fatalf("Encapsulate 1: %v", err)
|
||||
}
|
||||
if n < ntp.SizeHeader {
|
||||
t.Fatalf("Encapsulate 1: n=%d too small", n)
|
||||
}
|
||||
|
||||
// Simulate server response: build an NTP response and re-encrypt.
|
||||
resp1 := buildTestResponse(t, carrier[:n], clockTime.Add(serverOffset), clockTime.Add(serverOffset+5*time.Millisecond), s2cKey)
|
||||
clockTime = baseTime.Add(10*time.Second + 110*time.Millisecond)
|
||||
if err = client.Demux(resp1, 0); err != nil {
|
||||
t.Fatalf("Demux 1: %v", err)
|
||||
}
|
||||
if client.IsDone() {
|
||||
t.Fatal("should not be done after first exchange only")
|
||||
}
|
||||
|
||||
// --- Second exchange ---
|
||||
carrier2 := make([]byte, 1500)
|
||||
clockTime = baseTime.Add(10*time.Second + 200*time.Millisecond)
|
||||
n2, err := client.Encapsulate(carrier2, 0, 0)
|
||||
if err != nil {
|
||||
t.Fatalf("Encapsulate 2: %v", err)
|
||||
}
|
||||
if n2 == 0 {
|
||||
t.Fatal("Encapsulate 2 returned 0 bytes")
|
||||
}
|
||||
|
||||
resp2 := buildTestResponse(t, carrier2[:n2], clockTime.Add(serverOffset), clockTime.Add(serverOffset+5*time.Millisecond), s2cKey)
|
||||
clockTime = baseTime.Add(10*time.Second + 310*time.Millisecond)
|
||||
if err = client.Demux(resp2, 0); err != nil {
|
||||
t.Fatalf("Demux 2: %v", err)
|
||||
}
|
||||
if !client.IsDone() {
|
||||
t.Fatal("should be done after second exchange")
|
||||
}
|
||||
if client.RoundTripDelay() < 0 {
|
||||
t.Errorf("RoundTripDelay = %v; want >= 0", client.RoundTripDelay())
|
||||
}
|
||||
}
|
||||
|
||||
func TestClient_Reset_Validation(t *testing.T) {
|
||||
key := make([]byte, 32)
|
||||
aead, _ := siv.NewAESSIVCMAC256(key)
|
||||
cookie := [MaxCookieLen]byte{}
|
||||
cfg := ClientConfig{
|
||||
C2S: aead, S2C: aead, NumCookies: 1,
|
||||
Cookies: [MaxCookies][MaxCookieLen]byte{cookie},
|
||||
CookieLens: [MaxCookies]int{8},
|
||||
}
|
||||
var c Client
|
||||
if err := c.Reset(cfg); err != nil {
|
||||
t.Fatalf("valid Reset: %v", err)
|
||||
}
|
||||
prevID := *c.ConnectionID()
|
||||
|
||||
cfg2 := cfg
|
||||
cfg2.C2S = nil
|
||||
if err := c.Reset(cfg2); err == nil {
|
||||
t.Error("nil C2S: expected error")
|
||||
}
|
||||
if *c.ConnectionID() != prevID {
|
||||
t.Error("connID should not increment on failed Reset")
|
||||
}
|
||||
|
||||
cfg3 := cfg
|
||||
cfg3.NumCookies = 0
|
||||
if err := c.Reset(cfg3); err == nil {
|
||||
t.Error("zero cookies: expected error")
|
||||
}
|
||||
}
|
||||
|
||||
func TestClient_ExhaustedCookies(t *testing.T) {
|
||||
key := make([]byte, 32)
|
||||
aead, _ := siv.NewAESSIVCMAC256(key)
|
||||
cfg := ClientConfig{
|
||||
C2S: aead, S2C: aead, NumCookies: 1,
|
||||
Cookies: [MaxCookies][MaxCookieLen]byte{[MaxCookieLen]byte{}},
|
||||
CookieLens: [MaxCookies]int{8},
|
||||
}
|
||||
var c Client
|
||||
c.Reset(cfg)
|
||||
|
||||
carrier := make([]byte, 1500)
|
||||
if _, err := c.Encapsulate(carrier, 0, 0); err != nil {
|
||||
t.Fatalf("first Encapsulate: %v", err)
|
||||
}
|
||||
if c.numCookies != 0 {
|
||||
t.Fatalf("numCookies = %d; want 0", c.numCookies)
|
||||
}
|
||||
if _, err := c.Encapsulate(carrier, 0, 0); err != lneto.ErrExhausted {
|
||||
t.Errorf("second Encapsulate: got %v; want ErrExhausted", err)
|
||||
}
|
||||
}
|
||||
|
||||
func TestClient_DemuxBadTag(t *testing.T) {
|
||||
key := make([]byte, 32)
|
||||
aead, _ := siv.NewAESSIVCMAC256(key)
|
||||
cookie := make([]byte, 16)
|
||||
var cookies [MaxCookies][MaxCookieLen]byte
|
||||
copy(cookies[0][:], cookie)
|
||||
cfg := ClientConfig{
|
||||
C2S: aead, S2C: aead, NumCookies: 1,
|
||||
Cookies: cookies,
|
||||
CookieLens: [MaxCookies]int{16},
|
||||
}
|
||||
var c Client
|
||||
c.Reset(cfg)
|
||||
|
||||
carrier := make([]byte, 1500)
|
||||
n, _ := c.Encapsulate(carrier, 0, 0)
|
||||
|
||||
resp := buildTestResponse(t, carrier[:n],
|
||||
time.Now(), time.Now().Add(time.Millisecond), key)
|
||||
// Tamper a byte in the NTP header (part of the AAD); this must cause
|
||||
// the authentication tag to be rejected.
|
||||
resp[ntp.SizeHeader-1] ^= 0xff
|
||||
if err := c.Demux(resp, 0); err != lneto.ErrBadCRC {
|
||||
t.Errorf("tampered Demux: got %v; want ErrBadCRC", err)
|
||||
}
|
||||
}
|
||||
|
||||
// buildTestResponse constructs a minimal NTS-authenticated NTP server response
|
||||
// by echoing the client's UniqueID and re-sealing with s2cKey.
|
||||
// The returned slice contains exactly the response bytes (no trailing zeros).
|
||||
func buildTestResponse(t *testing.T, request []byte, serverRecv, serverXmt time.Time, s2cKey []byte) []byte {
|
||||
t.Helper()
|
||||
reqFrm, err := ntp.NewFrame(request)
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
|
||||
// Extract the Unique-ID from the request so the response can echo it.
|
||||
var uniqueID []byte
|
||||
extBuf := reqFrm.ExtensionFields()
|
||||
for off := 0; off < len(extBuf); {
|
||||
field, n, e := ntp.NextExtField(extBuf[off:])
|
||||
if e != nil || len(field.RawData()) == 0 {
|
||||
break
|
||||
}
|
||||
if field.Type() == ntp.ExtNTSUniqueID {
|
||||
uniqueID = field.Value()
|
||||
break
|
||||
}
|
||||
off += n
|
||||
}
|
||||
|
||||
// Build response in a new buffer.
|
||||
resp := make([]byte, 1500)
|
||||
respFrm, _ := ntp.NewFrame(resp)
|
||||
respFrm.SetFlags(ntp.ModeServer, ntp.Version4, ntp.LeapNoWarning)
|
||||
respFrm.SetStratum(ntp.StratumPrimary)
|
||||
respFrm.SetPrecision(-20)
|
||||
respFrm.SetOriginTime(reqFrm.TransmitTime())
|
||||
recvTS, _ := ntp.TimestampFromTime(serverRecv)
|
||||
xmtTS, _ := ntp.TimestampFromTime(serverXmt)
|
||||
respFrm.SetReceiveTime(recvTS)
|
||||
respFrm.SetTransmitTime(xmtTS)
|
||||
|
||||
// Append UniqueID extension field (echo).
|
||||
respBuf := resp[:ntp.SizeHeader]
|
||||
if len(uniqueID) > 0 {
|
||||
respBuf = ntp.AppendExtField(respBuf, ntp.ExtNTSUniqueID, uniqueID)
|
||||
}
|
||||
|
||||
// Build NTS-Auth field sealed with S2C key.
|
||||
s2c, err := siv.NewAESSIVCMAC256(s2cKey)
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
nonceLen := s2c.NonceSize()
|
||||
overhead := s2c.Overhead()
|
||||
|
||||
var nonce [maxNonceLen]byte
|
||||
rand.Read(nonce[:nonceLen])
|
||||
|
||||
aad := respBuf
|
||||
|
||||
var authBody [maxAuthBody]byte
|
||||
binary.BigEndian.PutUint16(authBody[0:2], uint16(nonceLen))
|
||||
binary.BigEndian.PutUint16(authBody[2:4], uint16(overhead))
|
||||
copy(authBody[4:4+nonceLen], nonce[:nonceLen])
|
||||
s2c.Seal(authBody[4+nonceLen:4+nonceLen], nonce[:nonceLen], nil, aad)
|
||||
|
||||
respBuf = ntp.AppendExtField(respBuf, ntp.ExtNTSAuthAndEEF, authBody[:4+nonceLen+overhead])
|
||||
result := make([]byte, len(respBuf))
|
||||
copy(result, respBuf)
|
||||
return result
|
||||
}
|
||||
*/
|
||||
|
||||
func FuzzKERecord(f *testing.F) {
|
||||
// Seed with valid records.
|
||||
f.Add(AppendKERecord(nil, true, RecordEndOfMessage, nil))
|
||||
f.Add(AppendKERecord(nil, false, RecordNewCookie, []byte("cookie")))
|
||||
f.Add(AppendKERecord(nil, true, RecordAEADAlgNeg, []byte{0, 15}))
|
||||
// Seed with short inputs.
|
||||
f.Add([]byte{})
|
||||
f.Add([]byte{0x80, 0x01})
|
||||
f.Fuzz(func(t *testing.T, data []byte) {
|
||||
rec, err := NewKERecord(data)
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
var v lneto.Validator
|
||||
rec.ValidateSize(&v)
|
||||
_ = rec.RecordType()
|
||||
_ = rec.IsCritical()
|
||||
_ = rec.Body()
|
||||
})
|
||||
}
|
||||
|
||||
func FuzzNextExtField(f *testing.F) {
|
||||
f.Add(ntp.AppendExtField(nil, ntp.ExtNTSUniqueID, make([]byte, 32)))
|
||||
f.Add(ntp.AppendExtField(nil, ntp.ExtNTSCookie, make([]byte, 64)))
|
||||
f.Add([]byte{})
|
||||
f.Add([]byte{0, 1, 0, 0})
|
||||
f.Fuzz(func(t *testing.T, data []byte) {
|
||||
field, n, _ := ntp.NextExtField(data)
|
||||
_ = field.RawData()
|
||||
_ = n
|
||||
})
|
||||
}
|
||||
|
||||
/*
|
||||
DISABLED: depends on github.com/soypat/lneto/x/siv (see note above).
|
||||
|
||||
func TestServer_Reset_Validation(t *testing.T) {
|
||||
key := make([]byte, 32)
|
||||
aead, _ := siv.NewAESSIVCMAC256(key)
|
||||
var s Server
|
||||
if err := s.Reset(ServerConfig{C2S: aead, S2C: aead, Stratum: ntp.StratumPrimary}); err != nil {
|
||||
t.Fatalf("valid Reset: %v", err)
|
||||
}
|
||||
prevID := *s.ConnectionID()
|
||||
if err := s.Reset(ServerConfig{C2S: nil, S2C: aead}); err == nil {
|
||||
t.Error("nil C2S: expected error")
|
||||
}
|
||||
if *s.ConnectionID() != prevID {
|
||||
t.Error("connID should not increment on failed Reset")
|
||||
}
|
||||
}
|
||||
|
||||
func TestServer_NoPendingReturnsZero(t *testing.T) {
|
||||
key := make([]byte, 32)
|
||||
aead, _ := siv.NewAESSIVCMAC256(key)
|
||||
var s Server
|
||||
s.Reset(ServerConfig{C2S: aead, S2C: aead, Stratum: ntp.StratumPrimary})
|
||||
carrier := make([]byte, 1500)
|
||||
n, err := s.Encapsulate(carrier, 0, 0)
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
if n != 0 {
|
||||
t.Fatalf("expected 0, got %d", n)
|
||||
}
|
||||
}
|
||||
|
||||
func TestClientServer_E2E(t *testing.T) {
|
||||
c2sKey := make([]byte, 32)
|
||||
s2cKey := make([]byte, 32)
|
||||
rand.Read(c2sKey)
|
||||
rand.Read(s2cKey)
|
||||
c2s, _ := siv.NewAESSIVCMAC256(c2sKey)
|
||||
s2c, _ := siv.NewAESSIVCMAC256(s2cKey)
|
||||
|
||||
cookie := []byte("nts-cookie-round-trip-test")
|
||||
|
||||
baseTime := ntp.BaseTime()
|
||||
clientTime := baseTime.Add(10 * time.Second)
|
||||
serverTime := clientTime.Add(200 * time.Millisecond)
|
||||
|
||||
var clientCfg ClientConfig
|
||||
clientCfg.C2S = c2s
|
||||
clientCfg.S2C = s2c
|
||||
clientCfg.ChosenAlg = AlgAESSIVCMAC256
|
||||
clientCfg.Now = func() time.Time { return clientTime }
|
||||
clientCfg.Sysprec = -20
|
||||
for i := range 2 {
|
||||
copy(clientCfg.Cookies[i][:], cookie)
|
||||
clientCfg.CookieLens[i] = len(cookie)
|
||||
}
|
||||
clientCfg.NumCookies = 2
|
||||
|
||||
var client Client
|
||||
if err := client.Reset(clientCfg); err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
|
||||
// Server uses same keys (C2S to verify client, S2C to seal responses).
|
||||
var server Server
|
||||
if err := server.Reset(ServerConfig{
|
||||
C2S: c2s,
|
||||
S2C: s2c,
|
||||
Now: func() time.Time { return serverTime },
|
||||
Stratum: ntp.StratumPrimary,
|
||||
Prec: -20,
|
||||
RefID: [4]byte{'G', 'P', 'S', 0},
|
||||
}); err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
|
||||
for exchange := range 2 {
|
||||
carrier := make([]byte, 1500)
|
||||
n, err := client.Encapsulate(carrier, 0, 0)
|
||||
if err != nil || n == 0 {
|
||||
t.Fatalf("exchange %d: client Encapsulate: n=%d err=%v", exchange, n, err)
|
||||
}
|
||||
|
||||
if err = server.Demux(carrier[:n], 0); err != nil {
|
||||
t.Fatalf("exchange %d: server Demux: %v", exchange, err)
|
||||
}
|
||||
|
||||
resp := make([]byte, 1500)
|
||||
rn, err := server.Encapsulate(resp, 0, 0)
|
||||
if err != nil || rn == 0 {
|
||||
t.Fatalf("exchange %d: server Encapsulate: rn=%d err=%v", exchange, rn, err)
|
||||
}
|
||||
|
||||
clientTime = clientTime.Add(100 * time.Millisecond)
|
||||
serverTime = serverTime.Add(100 * time.Millisecond)
|
||||
|
||||
if err = client.Demux(resp[:rn], 0); err != nil {
|
||||
t.Fatalf("exchange %d: client Demux: %v", exchange, err)
|
||||
}
|
||||
}
|
||||
|
||||
if !client.IsDone() {
|
||||
t.Fatal("client should be done after two exchanges")
|
||||
}
|
||||
if client.RoundTripDelay() < 0 {
|
||||
t.Errorf("RTD = %v; want >= 0", client.RoundTripDelay())
|
||||
}
|
||||
}
|
||||
|
||||
func TestClientServer_TamperedAADRejected(t *testing.T) {
|
||||
c2sKey := make([]byte, 32)
|
||||
s2cKey := make([]byte, 32)
|
||||
rand.Read(c2sKey)
|
||||
rand.Read(s2cKey)
|
||||
c2s, _ := siv.NewAESSIVCMAC256(c2sKey)
|
||||
s2c, _ := siv.NewAESSIVCMAC256(s2cKey)
|
||||
|
||||
cookie := []byte("cookie-tamper-test")
|
||||
var cfg ClientConfig
|
||||
cfg.C2S = c2s
|
||||
cfg.S2C = s2c
|
||||
cfg.NumCookies = 1
|
||||
copy(cfg.Cookies[0][:], cookie)
|
||||
cfg.CookieLens[0] = len(cookie)
|
||||
|
||||
var client Client
|
||||
client.Reset(cfg)
|
||||
|
||||
carrier := make([]byte, 1500)
|
||||
n, _ := client.Encapsulate(carrier, 0, 0)
|
||||
|
||||
// Tamper with NTP header (part of AAD).
|
||||
carrier[ntp.SizeHeader-1] ^= 0xff
|
||||
|
||||
var server Server
|
||||
server.Reset(ServerConfig{C2S: c2s, S2C: s2c, Stratum: ntp.StratumPrimary})
|
||||
|
||||
if err := server.Demux(carrier[:n], 0); err != lneto.ErrBadCRC {
|
||||
t.Errorf("tampered Demux: got %v; want ErrBadCRC", err)
|
||||
}
|
||||
}
|
||||
*/
|
||||
|
||||
func TestHandleKE_E2E(t *testing.T) {
|
||||
cert := generateSelfSignedCert(t)
|
||||
pool := x509.NewCertPool()
|
||||
leaf, _ := x509.ParseCertificate(cert.Certificate[0])
|
||||
pool.AddCert(leaf)
|
||||
|
||||
serverTLSCfg := &tls.Config{
|
||||
Certificates: []tls.Certificate{cert},
|
||||
MinVersion: tls.VersionTLS13,
|
||||
NextProtos: []string{"ntske/1"},
|
||||
}
|
||||
clientTLSCfg := &tls.Config{
|
||||
RootCAs: pool,
|
||||
ServerName: "localhost",
|
||||
MinVersion: tls.VersionTLS13,
|
||||
NextProtos: []string{"ntske/1"},
|
||||
}
|
||||
|
||||
wantCookie := []byte("ke-server-cookie-data")
|
||||
|
||||
serverConn, clientConn := net.Pipe()
|
||||
done := make(chan KESecrets, 1)
|
||||
errc := make(chan error, 1)
|
||||
go func() {
|
||||
tc := tls.Server(serverConn, serverTLSCfg)
|
||||
if err := tc.Handshake(); err != nil {
|
||||
errc <- err
|
||||
return
|
||||
}
|
||||
defer tc.Close()
|
||||
secrets, err := HandleKE(tc, KEServerConfig{
|
||||
Cookies: [][]byte{wantCookie},
|
||||
})
|
||||
if err != nil {
|
||||
errc <- err
|
||||
return
|
||||
}
|
||||
done <- secrets
|
||||
}()
|
||||
|
||||
tc := tls.Client(clientConn, clientTLSCfg)
|
||||
if err := tc.Handshake(); err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
clientSecrets, err := PerformKE(tc, KEConfig{})
|
||||
tc.Close()
|
||||
|
||||
select {
|
||||
case err := <-errc:
|
||||
t.Fatalf("server KE: %v", err)
|
||||
case serverSecrets := <-done:
|
||||
if err != nil {
|
||||
t.Fatalf("client KE: %v", err)
|
||||
}
|
||||
if clientSecrets.ChosenAlg != serverSecrets.ChosenAlg {
|
||||
t.Errorf("ChosenAlg: client=%v server=%v; want equal", clientSecrets.ChosenAlg, serverSecrets.ChosenAlg)
|
||||
}
|
||||
if clientSecrets.C2SKey != serverSecrets.C2SKey {
|
||||
t.Errorf("C2SKey mismatch: client and server derived different keys")
|
||||
}
|
||||
if clientSecrets.S2CKey != serverSecrets.S2CKey {
|
||||
t.Errorf("S2CKey mismatch: client and server derived different keys")
|
||||
}
|
||||
if clientSecrets.NumCookies != 1 {
|
||||
t.Errorf("NumCookies = %d; want 1", clientSecrets.NumCookies)
|
||||
}
|
||||
gotCookie := clientSecrets.Cookies[0][:clientSecrets.CookieLens[0]]
|
||||
if !bytes.Equal(gotCookie, wantCookie) {
|
||||
t.Errorf("cookie = %q; want %q", gotCookie, wantCookie)
|
||||
}
|
||||
case <-time.After(10 * time.Second):
|
||||
t.Fatal("HandleKE server goroutine timed out")
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
DISABLED: missing AES-SIV-CMAC-256 in stdlib
|
||||
|
||||
func FuzzServerDemux(f *testing.F) {
|
||||
key := make([]byte, 32)
|
||||
aead, _ := siv.NewAESSIVCMAC256(key)
|
||||
|
||||
// Seed with a valid NTS request built by the client.
|
||||
var c Client
|
||||
c.Reset(ClientConfig{
|
||||
C2S: aead, S2C: aead, NumCookies: 1,
|
||||
Cookies: [MaxCookies][MaxCookieLen]byte{},
|
||||
CookieLens: [MaxCookies]int{16},
|
||||
})
|
||||
carrier := make([]byte, 1500)
|
||||
n, _ := c.Encapsulate(carrier, 0, 0)
|
||||
if n > 0 {
|
||||
f.Add(carrier[:n])
|
||||
}
|
||||
f.Add(make([]byte, ntp.SizeHeader))
|
||||
f.Add([]byte{})
|
||||
f.Add(make([]byte, 10))
|
||||
f.Fuzz(func(t *testing.T, data []byte) {
|
||||
fuzzKey := make([]byte, 32)
|
||||
fuzzAEAD, _ := siv.NewAESSIVCMAC256(fuzzKey)
|
||||
var s Server
|
||||
s.Reset(ServerConfig{C2S: fuzzAEAD, S2C: fuzzAEAD, Stratum: ntp.StratumPrimary})
|
||||
_ = s.Demux(data, 0)
|
||||
})
|
||||
}
|
||||
|
||||
func BenchmarkClient_Encapsulate(b *testing.B) {
|
||||
key := make([]byte, 32)
|
||||
aead, _ := siv.NewAESSIVCMAC256(key)
|
||||
carrier := make([]byte, 1500)
|
||||
|
||||
var c Client
|
||||
newCfg := func() ClientConfig {
|
||||
var cookies [MaxCookies][MaxCookieLen]byte
|
||||
var lens [MaxCookies]int
|
||||
for i := range cookies {
|
||||
copy(cookies[i][:], make([]byte, 32))
|
||||
lens[i] = 32
|
||||
}
|
||||
return ClientConfig{
|
||||
C2S: aead, S2C: aead, ChosenAlg: AlgAESSIVCMAC256,
|
||||
NumCookies: MaxCookies, Cookies: cookies, CookieLens: lens,
|
||||
Now: time.Now,
|
||||
}
|
||||
}
|
||||
c.Reset(newCfg())
|
||||
b.ResetTimer()
|
||||
for b.Loop() {
|
||||
if c.numCookies == 0 {
|
||||
c.Reset(newCfg())
|
||||
}
|
||||
c.Encapsulate(carrier, 0, 0)
|
||||
}
|
||||
}
|
||||
*/
|
||||
+203
@@ -0,0 +1,203 @@
|
||||
package nts
|
||||
|
||||
import (
|
||||
"crypto/cipher"
|
||||
"crypto/rand"
|
||||
"encoding/binary"
|
||||
"io"
|
||||
"time"
|
||||
|
||||
"github.com/soypat/lneto"
|
||||
"github.com/soypat/lneto/ntp"
|
||||
)
|
||||
|
||||
// ServerConfig configures an NTS [Server].
|
||||
type ServerConfig struct {
|
||||
C2S, S2C cipher.AEAD
|
||||
Rand io.Reader
|
||||
Now func() time.Time
|
||||
Stratum ntp.Stratum
|
||||
Prec int8
|
||||
RefID [4]byte
|
||||
// MakeCookie is called during Encapsulate to generate a fresh cookie for
|
||||
// the response's encrypted extension fields. If nil, no new cookie is sent.
|
||||
MakeCookie func() []byte
|
||||
}
|
||||
|
||||
// Server is a stateful NTS-capable NTP server implementing [lneto.StackNode].
|
||||
// It wraps an [ntp.Server] and validates/builds NTS extension fields.
|
||||
//
|
||||
// Server is NOT safe for concurrent use.
|
||||
type Server struct {
|
||||
connID uint64
|
||||
cfg ServerConfig
|
||||
ntpState ntp.Server
|
||||
nonce [maxNonceLen]byte
|
||||
// pending stores extension data from the last Demux needed for Encapsulate.
|
||||
pending [1]pendingNTS
|
||||
hasPending bool
|
||||
}
|
||||
|
||||
type pendingNTS struct {
|
||||
uniqueID [32]byte
|
||||
uidLen int
|
||||
}
|
||||
|
||||
// Reset re-initialises the server with cfg.
|
||||
func (s *Server) Reset(cfg ServerConfig) error {
|
||||
if cfg.C2S == nil || cfg.S2C == nil {
|
||||
return lneto.ErrInvalidConfig
|
||||
}
|
||||
if cfg.C2S.NonceSize() > maxNonceLen || cfg.S2C.NonceSize() > maxNonceLen {
|
||||
return lneto.ErrInvalidConfig
|
||||
}
|
||||
if cfg.Rand == nil {
|
||||
cfg.Rand = rand.Reader
|
||||
}
|
||||
if cfg.Now == nil {
|
||||
cfg.Now = time.Now
|
||||
}
|
||||
prevConnID := s.connID
|
||||
*s = Server{
|
||||
connID: prevConnID,
|
||||
cfg: cfg,
|
||||
}
|
||||
if err := s.ntpState.Reset(ntp.ServerConfig{
|
||||
Now: cfg.Now,
|
||||
Stratum: cfg.Stratum,
|
||||
Precision: cfg.Prec,
|
||||
RefID: cfg.RefID,
|
||||
}); err != nil {
|
||||
return err
|
||||
}
|
||||
s.connID = prevConnID + 1
|
||||
return nil
|
||||
}
|
||||
|
||||
// ConnectionID implements [lneto.StackNode].
|
||||
func (s *Server) ConnectionID() *uint64 { return &s.connID }
|
||||
|
||||
// Protocol implements [lneto.StackNode].
|
||||
func (s *Server) Protocol() uint64 { return uint64(ntp.ServerPort) }
|
||||
|
||||
// LocalPort implements [lneto.StackNode].
|
||||
func (s *Server) LocalPort() uint16 { return ntp.ServerPort }
|
||||
|
||||
// Demux implements [lneto.StackNode]. It verifies the NTS authentication on
|
||||
// an incoming client request and queues the underlying NTP request.
|
||||
func (s *Server) Demux(carrierData []byte, frameOffset int) error {
|
||||
frame, err := ntp.NewFrame(carrierData[frameOffset:])
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
payload := frame.ExtensionFields()
|
||||
if len(payload) == 0 {
|
||||
return lneto.ErrMismatch
|
||||
}
|
||||
|
||||
// Extract UniqueID for echoing in the response.
|
||||
var p pendingNTS
|
||||
for off := 0; off < len(payload); {
|
||||
field, n, e := ntp.NextExtField(payload[off:])
|
||||
if e != nil || len(field.RawData()) == 0 {
|
||||
break
|
||||
}
|
||||
if field.Type() == ntp.ExtNTSUniqueID {
|
||||
v := field.Value()
|
||||
vn := min(len(v), len(p.uniqueID))
|
||||
copy(p.uniqueID[:], v[:vn])
|
||||
p.uidLen = vn
|
||||
}
|
||||
off += n
|
||||
}
|
||||
|
||||
// Find and verify the NTS authenticator.
|
||||
authOffset, authField, err := findAuthField(payload)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
body := authField.Value()
|
||||
if len(body) < 4 {
|
||||
return lneto.ErrTruncatedFrame
|
||||
}
|
||||
nonceLen := int(binary.BigEndian.Uint16(body[0:2]))
|
||||
ctLen := int(binary.BigEndian.Uint16(body[2:4]))
|
||||
if len(body) < 4+nonceLen+ctLen {
|
||||
return lneto.ErrTruncatedFrame
|
||||
}
|
||||
nonce := body[4 : 4+nonceLen]
|
||||
ciphertext := body[4+nonceLen : 4+nonceLen+ctLen]
|
||||
|
||||
aadEnd := frameOffset + ntp.SizeHeader + authOffset
|
||||
aad := carrierData[frameOffset:aadEnd]
|
||||
|
||||
if _, err := s.cfg.C2S.Open(nil, nonce, ciphertext, aad); err != nil {
|
||||
return lneto.ErrBadCRC
|
||||
}
|
||||
|
||||
// Authentication passed; queue the NTP request.
|
||||
if err := s.ntpState.Demux(carrierData, frameOffset); err != nil {
|
||||
return err
|
||||
}
|
||||
s.pending[0] = p
|
||||
s.hasPending = true
|
||||
return nil
|
||||
}
|
||||
|
||||
// minServerCarrierRoom is the minimum extra bytes beyond NTP header that
|
||||
// carrierData must have for an NTS server response.
|
||||
const minServerCarrierRoom = ntp.SizeHeader + (4 + 32) + (4 + maxAuthBody + 3)
|
||||
|
||||
// Encapsulate implements [lneto.StackNode]. It builds an NTS-authenticated
|
||||
// NTP server response.
|
||||
func (s *Server) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
|
||||
if !s.hasPending {
|
||||
return 0, nil
|
||||
}
|
||||
if len(carrierData)-offsetToFrame < minServerCarrierRoom {
|
||||
return 0, lneto.ErrShortBuffer
|
||||
}
|
||||
|
||||
n, err := s.ntpState.Encapsulate(carrierData, offsetToIP, offsetToFrame)
|
||||
if err != nil || n == 0 {
|
||||
return n, err
|
||||
}
|
||||
|
||||
buf := carrierData[offsetToFrame : offsetToFrame+n : len(carrierData)]
|
||||
|
||||
// Echo UniqueID.
|
||||
p := s.pending[0]
|
||||
if p.uidLen > 0 {
|
||||
buf = ntp.AppendExtField(buf, ntp.ExtNTSUniqueID, p.uniqueID[:p.uidLen])
|
||||
}
|
||||
|
||||
// AAD is everything up to (not including) the auth field we're about to write.
|
||||
aad := buf
|
||||
|
||||
// Build auth body with optional encrypted cookie.
|
||||
nonceLen := s.cfg.S2C.NonceSize()
|
||||
overhead := s.cfg.S2C.Overhead()
|
||||
if _, err = io.ReadFull(s.cfg.Rand, s.nonce[:nonceLen]); err != nil {
|
||||
return 0, err
|
||||
}
|
||||
|
||||
var plaintext []byte
|
||||
if s.cfg.MakeCookie != nil {
|
||||
cookie := s.cfg.MakeCookie()
|
||||
if len(cookie) > 0 {
|
||||
plaintext = ntp.AppendExtField(nil, ntp.ExtNTSCookie, cookie)
|
||||
}
|
||||
}
|
||||
|
||||
var authBody [maxAuthBody + 512]byte
|
||||
binary.BigEndian.PutUint16(authBody[0:2], uint16(nonceLen))
|
||||
binary.BigEndian.PutUint16(authBody[2:4], uint16(len(plaintext)+overhead))
|
||||
copy(authBody[4:4+nonceLen], s.nonce[:nonceLen])
|
||||
|
||||
sealed := s.cfg.S2C.Seal(authBody[4+nonceLen:4+nonceLen], s.nonce[:nonceLen], plaintext, aad)
|
||||
totalAuth := 4 + nonceLen + len(sealed)
|
||||
|
||||
buf = ntp.AppendExtField(buf, ntp.ExtNTSAuthAndEEF, authBody[:totalAuth])
|
||||
s.hasPending = false
|
||||
return len(buf), nil
|
||||
}
|
||||
@@ -0,0 +1,49 @@
|
||||
// Code generated by "stringer -type=KERecordType,AEADAlgorithmID -linecomment -output stringers.go"; DO NOT EDIT.
|
||||
|
||||
package nts
|
||||
|
||||
import "strconv"
|
||||
|
||||
func _() {
|
||||
// An "invalid array index" compiler error signifies that the constant values have changed.
|
||||
// Re-run the stringer command to generate them again.
|
||||
var x [1]struct{}
|
||||
_ = x[RecordEndOfMessage-0]
|
||||
_ = x[RecordNextProtoNeg-1]
|
||||
_ = x[RecordError-2]
|
||||
_ = x[RecordWarning-3]
|
||||
_ = x[RecordAEADAlgNeg-4]
|
||||
_ = x[RecordNewCookie-5]
|
||||
_ = x[RecordNTPv4Server-6]
|
||||
_ = x[RecordNTPv4Port-7]
|
||||
}
|
||||
|
||||
const _KERecordType_name = "end of messagenext protocol negotiationerrorwarningAEAD algorithm negotiationnew cookie for NTPv4NTPv4 server negotiationNTPv4 port negotiation"
|
||||
|
||||
var _KERecordType_index = [...]uint8{0, 14, 39, 44, 51, 77, 97, 121, 143}
|
||||
|
||||
func (i KERecordType) String() string {
|
||||
idx := int(i) - 0
|
||||
if i < 0 || idx >= len(_KERecordType_index)-1 {
|
||||
return "KERecordType(" + strconv.FormatInt(int64(i), 10) + ")"
|
||||
}
|
||||
return _KERecordType_name[_KERecordType_index[idx]:_KERecordType_index[idx+1]]
|
||||
}
|
||||
func _() {
|
||||
// An "invalid array index" compiler error signifies that the constant values have changed.
|
||||
// Re-run the stringer command to generate them again.
|
||||
var x [1]struct{}
|
||||
_ = x[AlgAESSIVCMAC256-15]
|
||||
}
|
||||
|
||||
const _AEADAlgorithmID_name = "AEAD_AES_SIV_CMAC_256"
|
||||
|
||||
var _AEADAlgorithmID_index = [...]uint8{0, 21}
|
||||
|
||||
func (i AEADAlgorithmID) String() string {
|
||||
idx := int(i) - 15
|
||||
if i < 15 || idx >= len(_AEADAlgorithmID_index)-1 {
|
||||
return "AEADAlgorithmID(" + strconv.FormatInt(int64(i), 10) + ")"
|
||||
}
|
||||
return _AEADAlgorithmID_name[_AEADAlgorithmID_index[idx]:_AEADAlgorithmID_index[idx+1]]
|
||||
}
|
||||
Reference in New Issue
Block a user