mirror of https://github.com/tailscale/tailscale/
types/key: add a dedicated type for node keys.
Complete with converters to all the other types that represent a node key today, so the new type can gradually subsume old ones. Updates #3206 Signed-off-by: David Anderson <danderson@tailscale.com>pull/3211/head
David Anderson
3 years ago
committed by
Dave Anderson
parent
22dbaa0894
commit
bc89a796ec
@ -0,0 +1,333 @@
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// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package key
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import (
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"bufio"
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"bytes"
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"crypto/subtle"
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"encoding/hex"
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"errors"
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"go4.org/mem"
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"golang.org/x/crypto/curve25519"
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"golang.org/x/crypto/nacl/box"
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"tailscale.com/types/structs"
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"tailscale.com/types/wgkey"
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)
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const (
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// nodePrivateHexPrefix is the prefix used to identify a
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// hex-encoded node private key.
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//
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// This prefix name is a little unfortunate, in that it comes from
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// WireGuard's own key types, and we've used it for both key types
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// we persist to disk (machine and node keys). But we're stuck
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// with it for now, barring another round of tricky migration.
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nodePrivateHexPrefix = "privkey:"
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// nodePublicHexPrefix is the prefix used to identify a
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// hex-encoded node public key.
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//
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// This prefix is used in the control protocol, so cannot be
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// changed.
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nodePublicHexPrefix = "nodekey:"
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)
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// NodePrivate is a node key, used for WireGuard tunnels and
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// communication with DERP servers.
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type NodePrivate struct {
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_ structs.Incomparable // because == isn't constant-time
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k [32]byte
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}
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// NewNode creates and returns a new node private key.
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func NewNode() NodePrivate {
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var ret NodePrivate
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rand(ret.k[:])
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// WireGuard does its own clamping, so this would be unnecessary -
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// but we also use this key for DERP comms, which does require
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// clamping.
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clamp25519Private(ret.k[:])
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return ret
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}
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func ParseNodePrivateUntyped(raw mem.RO) (NodePrivate, error) {
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var ret NodePrivate
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if err := parseHex(ret.k[:], raw, mem.B(nil)); err != nil {
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return NodePrivate{}, err
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}
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return ret, nil
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}
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// IsZero reports whether k is the zero value.
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func (k NodePrivate) IsZero() bool {
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return k.Equal(NodePrivate{})
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}
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// Equal reports whether k and other are the same key.
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func (k NodePrivate) Equal(other NodePrivate) bool {
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return subtle.ConstantTimeCompare(k.k[:], other.k[:]) == 1
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}
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// Public returns the NodePublic for k.
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// Panics if NodePrivate is zero.
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func (k NodePrivate) Public() NodePublic {
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if k.IsZero() {
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panic("can't take the public key of a zero NodePrivate")
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}
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var ret NodePublic
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curve25519.ScalarBaseMult(&ret.k, &k.k)
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return ret
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}
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// MarshalText implements encoding.TextMarshaler.
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func (k NodePrivate) MarshalText() ([]byte, error) {
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return toHex(k.k[:], nodePrivateHexPrefix), nil
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}
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// MarshalText implements encoding.TextUnmarshaler.
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func (k *NodePrivate) UnmarshalText(b []byte) error {
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return parseHex(k.k[:], mem.B(b), mem.S(nodePrivateHexPrefix))
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}
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// SealTo wraps cleartext into a NaCl box (see
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// golang.org/x/crypto/nacl) to p, authenticated from k, using a
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// random nonce.
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//
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// The returned ciphertext is a 24-byte nonce concatenated with the
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// box value.
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func (k NodePrivate) SealTo(p NodePublic, cleartext []byte) (ciphertext []byte) {
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if k.IsZero() || p.IsZero() {
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panic("can't seal with zero keys")
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}
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var nonce [24]byte
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rand(nonce[:])
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return box.Seal(nonce[:], cleartext, &nonce, &p.k, &k.k)
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}
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// OpenFrom opens the NaCl box ciphertext, which must be a value
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// created by SealTo, and returns the inner cleartext if ciphertext is
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// a valid box from p to k.
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func (k NodePrivate) OpenFrom(p NodePublic, ciphertext []byte) (cleartext []byte, ok bool) {
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if k.IsZero() || p.IsZero() {
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panic("can't open with zero keys")
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}
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if len(ciphertext) < 24 {
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return nil, false
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}
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nonce := (*[24]byte)(ciphertext)
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return box.Open(nil, ciphertext[len(nonce):], nonce, &p.k, &k.k)
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}
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func (k NodePrivate) UntypedHexString() string {
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return hex.EncodeToString(k.k[:])
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}
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// AsPrivate returns k converted to a Private.
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//
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// Deprecated: exists only as a compatibility bridge while Private
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// gets removed from the codebase. Do not introduce new uses that
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// aren't related to #3206.
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func (k NodePrivate) AsPrivate() Private {
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return k.k
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}
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// AsWGPrivate returns k converted to a wgkey.Private.
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//
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// Deprecated: exists only as a compatibility bridge while
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// wgkey.Private gets removed from the codebase. Do not introduce new
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// uses that aren't related to #3206.
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func (k NodePrivate) AsWGPrivate() wgkey.Private {
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return k.k
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}
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// NodePublic is the public portion of a NodePrivate.
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type NodePublic struct {
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k [32]byte
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}
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// ParseNodePublicUntyped parses an untyped 64-character hex value
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// as a NodePublic.
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//
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// Deprecated: this function is risky to use, because it cannot verify
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// that the hex string was intended to be a NodePublic. This can
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// lead to accidentally decoding one type of key as another. For new
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// uses that don't require backwards compatibility with the untyped
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// string format, please use MarshalText/UnmarshalText.
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func ParseNodePublicUntyped(raw mem.RO) (NodePublic, error) {
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var ret NodePublic
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if err := parseHex(ret.k[:], raw, mem.B(nil)); err != nil {
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return NodePublic{}, err
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}
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return ret, nil
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}
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// NodePublicFromRaw32 parses a 32-byte raw value as a NodePublic.
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//
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// This should be used only when deserializing a NodePublic from a
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// binary protocol.
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func NodePublicFromRaw32(raw mem.RO) NodePublic {
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if raw.Len() != 32 {
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panic("input has wrong size")
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}
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var ret NodePublic
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raw.Copy(ret.k[:])
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return ret
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}
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// IsZero reports whether k is the zero value.
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func (k NodePublic) IsZero() bool {
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return k == NodePublic{}
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}
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// ShortString returns the Tailscale conventional debug representation
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// of a public key: the first five base64 digits of the key, in square
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// brackets.
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func (k NodePublic) ShortString() string {
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return debug32(k.k)
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}
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// AppendTo appends k, serialized as a 32-byte binary value, to
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// buf. Returns the new slice.
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func (k NodePublic) AppendTo(buf []byte) []byte {
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return append(buf, k.k[:]...)
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}
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// RawLen returns the length of k when to the format handled by
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// ReadRawWithoutAllocating and WriteRawWithoutAllocating.
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func (k NodePublic) RawLen() int {
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return 32
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}
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// ReadRawWithoutAllocating initializes k with bytes read from br.
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// The reading is done ~4x slower than io.ReadFull, but in exchange is
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// allocation-free.
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func (k *NodePublic) ReadRawWithoutAllocating(br *bufio.Reader) error {
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var z NodePublic
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if *k != z {
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return errors.New("refusing to read into non-zero NodePublic")
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}
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// This is ~4x slower than io.ReadFull, but using io.ReadFull
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// causes one extra alloc, which is significant for the DERP
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// server that consumes this method. So, process stuff slower but
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// without allocation.
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//
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// Dear future: if io.ReadFull stops causing stuff to escape, you
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// should switch back to that.
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for i := range k.k {
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b, err := br.ReadByte()
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if err != nil {
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return err
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}
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k.k[i] = b
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}
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return nil
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}
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// WriteRawWithoutAllocating writes out k as 32 bytes to bw.
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// The writing is done ~3x slower than bw.Write, but in exchange is
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// allocation-free.
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func (k NodePublic) WriteRawWithoutAllocating(bw *bufio.Writer) error {
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// Equivalent to bw.Write(k.k[:]), but without causing an
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// escape-related alloc.
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//
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// Dear future: if bw.Write(k.k[:]) stops causing stuff to escape,
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// you should switch back to that.
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for _, b := range k.k {
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err := bw.WriteByte(b)
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if err != nil {
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return err
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}
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}
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return nil
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}
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// Raw32 returns k encoded as 32 raw bytes.
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//
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// Deprecated: only needed for a single legacy use in the control
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// server, don't add more uses.
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func (k NodePublic) Raw32() [32]byte {
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var ret [32]byte
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copy(ret[:], k.k[:])
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return ret
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}
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// Less reports whether k orders before other, using an undocumented
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// deterministic ordering.
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func (k NodePublic) Less(other NodePublic) bool {
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return bytes.Compare(k.k[:], other.k[:]) < 0
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}
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// UntypedHexString returns k, encoded as an untyped 64-character hex
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// string.
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//
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// Deprecated: this function is risky to use, because it produces
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// serialized values that do not identify themselves as a
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// NodePublic, allowing other code to potentially parse it back in
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// as the wrong key type. For new uses that don't require backwards
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// compatibility with the untyped string format, please use
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// MarshalText/UnmarshalText.
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func (k NodePublic) UntypedHexString() string {
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return hex.EncodeToString(k.k[:])
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}
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// String returns the output of MarshalText as a string.
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func (k NodePublic) String() string {
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bs, err := k.MarshalText()
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if err != nil {
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panic(err)
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}
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return string(bs)
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}
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// MarshalText implements encoding.TextMarshaler.
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func (k NodePublic) MarshalText() ([]byte, error) {
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return toHex(k.k[:], nodePublicHexPrefix), nil
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}
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// MarshalText implements encoding.TextUnmarshaler.
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func (k *NodePublic) UnmarshalText(b []byte) error {
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return parseHex(k.k[:], mem.B(b), mem.S(nodePublicHexPrefix))
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}
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// WireGuardGoString prints k in the same format used by wireguard-go.
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func (k NodePublic) WireGuardGoString() string {
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// This implementation deliberately matches the overly complicated
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// implementation in wireguard-go.
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b64 := func(input byte) byte {
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return input + 'A' + byte(((25-int(input))>>8)&6) - byte(((51-int(input))>>8)&75) - byte(((61-int(input))>>8)&15) + byte(((62-int(input))>>8)&3)
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}
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b := []byte("peer(____…____)")
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const first = len("peer(")
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const second = len("peer(____…")
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b[first+0] = b64((k.k[0] >> 2) & 63)
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b[first+1] = b64(((k.k[0] << 4) | (k.k[1] >> 4)) & 63)
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b[first+2] = b64(((k.k[1] << 2) | (k.k[2] >> 6)) & 63)
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b[first+3] = b64(k.k[2] & 63)
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b[second+0] = b64(k.k[29] & 63)
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b[second+1] = b64((k.k[30] >> 2) & 63)
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b[second+2] = b64(((k.k[30] << 4) | (k.k[31] >> 4)) & 63)
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b[second+3] = b64((k.k[31] << 2) & 63)
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return string(b)
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}
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// AsPublic returns k converted to a Public.
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//
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// Deprecated: exists only as a compatibility bridge while Public
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// gets removed from the codebase. Do not introduce new uses that
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// aren't related to #3206.
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func (k NodePublic) AsPublic() Public {
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return k.k
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}
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// AsWGKey returns k converted to a wgkey.Key.
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//
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// Deprecated: exists only as a compatibility bridge while
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// wgkey.Key gets removed from the codebase. Do not introduce new
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// uses that aren't related to #3206.
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func (k NodePublic) AsWGKey() wgkey.Key {
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return k.k
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}
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@ -0,0 +1,130 @@
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// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package key
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import (
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"bufio"
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"bytes"
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"encoding/json"
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"strings"
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"testing"
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)
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func TestNodeKey(t *testing.T) {
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k := NewNode()
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if k.IsZero() {
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t.Fatal("NodePrivate should not be zero")
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}
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p := k.Public()
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if p.IsZero() {
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t.Fatal("NodePublic should not be zero")
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}
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bs, err := p.MarshalText()
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if err != nil {
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t.Fatal(err)
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}
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if full, got := string(bs), ":"+p.UntypedHexString(); !strings.HasSuffix(full, got) {
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t.Fatalf("NodePublic.UntypedHexString is not a suffix of the typed serialization, got %q want suffix of %q", got, full)
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}
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z := NodePublic{}
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if !z.IsZero() {
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t.Fatal("IsZero(NodePublic{}) is false")
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}
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if s := z.ShortString(); s != "" {
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t.Fatalf("NodePublic{}.ShortString() is %q, want \"\"", s)
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}
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}
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func TestNodeSerialization(t *testing.T) {
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serialized := `{
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"Priv": "privkey:40ab1b58e9076c7a4d9d07291f5edf9d1aa017eb949624ba683317f48a640369",
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"Pub":"nodekey:50d20b455ecf12bc453f83c2cfdb2a24925d06cf2598dcaa54e91af82ce9f765"
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}`
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// Carefully check that the expected serialized data decodes and
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// re-encodes to the expected keys. These types are serialized to
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// disk all over the place and need to be stable.
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priv := NodePrivate{
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k: [32]uint8{
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0x40, 0xab, 0x1b, 0x58, 0xe9, 0x7, 0x6c, 0x7a, 0x4d, 0x9d, 0x7,
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0x29, 0x1f, 0x5e, 0xdf, 0x9d, 0x1a, 0xa0, 0x17, 0xeb, 0x94,
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0x96, 0x24, 0xba, 0x68, 0x33, 0x17, 0xf4, 0x8a, 0x64, 0x3, 0x69,
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},
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}
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pub := NodePublic{
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k: [32]uint8{
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0x50, 0xd2, 0xb, 0x45, 0x5e, 0xcf, 0x12, 0xbc, 0x45, 0x3f, 0x83,
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0xc2, 0xcf, 0xdb, 0x2a, 0x24, 0x92, 0x5d, 0x6, 0xcf, 0x25, 0x98,
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0xdc, 0xaa, 0x54, 0xe9, 0x1a, 0xf8, 0x2c, 0xe9, 0xf7, 0x65,
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},
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}
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type keypair struct {
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Priv NodePrivate
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Pub NodePublic
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}
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var a keypair
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if err := json.Unmarshal([]byte(serialized), &a); err != nil {
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t.Fatal(err)
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}
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if !a.Priv.Equal(priv) {
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t.Errorf("wrong deserialization of private key, got %#v want %#v", a.Priv, priv)
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}
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if a.Pub != pub {
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t.Errorf("wrong deserialization of public key, got %#v want %#v", a.Pub, pub)
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}
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bs, err := json.MarshalIndent(a, "", " ")
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if err != nil {
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t.Fatal(err)
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}
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var b bytes.Buffer
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json.Indent(&b, []byte(serialized), "", " ")
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if got, want := string(bs), b.String(); got != want {
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t.Error("json serialization doesn't roundtrip")
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}
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}
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func TestNodeReadRawWithoutAllocating(t *testing.T) {
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buf := make([]byte, 32)
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for i := range buf {
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buf[i] = 0x42
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}
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r := bytes.NewReader(buf)
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br := bufio.NewReader(r)
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got := testing.AllocsPerRun(1000, func() {
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r.Reset(buf)
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br.Reset(r)
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var k NodePublic
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if err := k.ReadRawWithoutAllocating(br); err != nil {
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t.Fatalf("ReadRawWithoutAllocating: %v", err)
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}
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})
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if want := 0.0; got != want {
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t.Fatalf("ReadRawWithoutAllocating got %f allocs, want %f", got, want)
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}
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}
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func TestNodeWriteRawWithoutAllocating(t *testing.T) {
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buf := make([]byte, 0, 32)
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w := bytes.NewBuffer(buf)
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bw := bufio.NewWriter(w)
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got := testing.AllocsPerRun(1000, func() {
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w.Reset()
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bw.Reset(w)
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var k NodePublic
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if err := k.WriteRawWithoutAllocating(bw); err != nil {
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t.Fatalf("WriteRawWithoutAllocating: %v", err)
|
||||
}
|
||||
})
|
||||
if want := 0.0; got != want {
|
||||
t.Fatalf("WriteRawWithoutAllocating got %f allocs, want %f", got, want)
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue