mirror of
https://github.com/tailscale/tailscale.git
synced 2024-12-04 23:45:34 +00:00
17b5782b3a
Fixes #3206 Signed-off-by: David Anderson <danderson@tailscale.com>
308 lines
9.0 KiB
Go
308 lines
9.0 KiB
Go
// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package key
|
|
|
|
import (
|
|
"bufio"
|
|
"bytes"
|
|
"crypto/subtle"
|
|
"encoding/hex"
|
|
"errors"
|
|
|
|
"go4.org/mem"
|
|
"golang.org/x/crypto/curve25519"
|
|
"golang.org/x/crypto/nacl/box"
|
|
"tailscale.com/types/structs"
|
|
)
|
|
|
|
const (
|
|
// nodePrivateHexPrefix is the prefix used to identify a
|
|
// hex-encoded node private key.
|
|
//
|
|
// This prefix name is a little unfortunate, in that it comes from
|
|
// WireGuard's own key types, and we've used it for both key types
|
|
// we persist to disk (machine and node keys). But we're stuck
|
|
// with it for now, barring another round of tricky migration.
|
|
nodePrivateHexPrefix = "privkey:"
|
|
|
|
// nodePublicHexPrefix is the prefix used to identify a
|
|
// hex-encoded node public key.
|
|
//
|
|
// This prefix is used in the control protocol, so cannot be
|
|
// changed.
|
|
nodePublicHexPrefix = "nodekey:"
|
|
|
|
// NodePublicRawLen is the length in bytes of a NodePublic, when
|
|
// serialized with AppendTo, Raw32 or WriteRawWithoutAllocating.
|
|
NodePublicRawLen = 32
|
|
)
|
|
|
|
// NodePrivate is a node key, used for WireGuard tunnels and
|
|
// communication with DERP servers.
|
|
type NodePrivate struct {
|
|
_ structs.Incomparable // because == isn't constant-time
|
|
k [32]byte
|
|
}
|
|
|
|
// NewNode creates and returns a new node private key.
|
|
func NewNode() NodePrivate {
|
|
var ret NodePrivate
|
|
rand(ret.k[:])
|
|
// WireGuard does its own clamping, so this would be unnecessary -
|
|
// but we also use this key for DERP comms, which does require
|
|
// clamping.
|
|
clamp25519Private(ret.k[:])
|
|
return ret
|
|
}
|
|
|
|
// NodePrivateFromRaw32 parses a 32-byte raw value as a NodePrivate.
|
|
//
|
|
// Deprecated: only needed to cast from legacy node private key types,
|
|
// do not add more uses unrelated to #3206.
|
|
func NodePrivateFromRaw32(raw mem.RO) NodePrivate {
|
|
if raw.Len() != 32 {
|
|
panic("input has wrong size")
|
|
}
|
|
var ret NodePrivate
|
|
raw.Copy(ret.k[:])
|
|
return ret
|
|
}
|
|
|
|
func ParseNodePrivateUntyped(raw mem.RO) (NodePrivate, error) {
|
|
var ret NodePrivate
|
|
if err := parseHex(ret.k[:], raw, mem.B(nil)); err != nil {
|
|
return NodePrivate{}, err
|
|
}
|
|
return ret, nil
|
|
}
|
|
|
|
// IsZero reports whether k is the zero value.
|
|
func (k NodePrivate) IsZero() bool {
|
|
return k.Equal(NodePrivate{})
|
|
}
|
|
|
|
// Equal reports whether k and other are the same key.
|
|
func (k NodePrivate) Equal(other NodePrivate) bool {
|
|
return subtle.ConstantTimeCompare(k.k[:], other.k[:]) == 1
|
|
}
|
|
|
|
// Public returns the NodePublic for k.
|
|
// Panics if NodePrivate is zero.
|
|
func (k NodePrivate) Public() NodePublic {
|
|
if k.IsZero() {
|
|
panic("can't take the public key of a zero NodePrivate")
|
|
}
|
|
var ret NodePublic
|
|
curve25519.ScalarBaseMult(&ret.k, &k.k)
|
|
return ret
|
|
}
|
|
|
|
// MarshalText implements encoding.TextMarshaler.
|
|
func (k NodePrivate) MarshalText() ([]byte, error) {
|
|
return toHex(k.k[:], nodePrivateHexPrefix), nil
|
|
}
|
|
|
|
// MarshalText implements encoding.TextUnmarshaler.
|
|
func (k *NodePrivate) UnmarshalText(b []byte) error {
|
|
return parseHex(k.k[:], mem.B(b), mem.S(nodePrivateHexPrefix))
|
|
}
|
|
|
|
// SealTo wraps cleartext into a NaCl box (see
|
|
// golang.org/x/crypto/nacl) to p, authenticated from k, using a
|
|
// random nonce.
|
|
//
|
|
// The returned ciphertext is a 24-byte nonce concatenated with the
|
|
// box value.
|
|
func (k NodePrivate) SealTo(p NodePublic, cleartext []byte) (ciphertext []byte) {
|
|
if k.IsZero() || p.IsZero() {
|
|
panic("can't seal with zero keys")
|
|
}
|
|
var nonce [24]byte
|
|
rand(nonce[:])
|
|
return box.Seal(nonce[:], cleartext, &nonce, &p.k, &k.k)
|
|
}
|
|
|
|
// OpenFrom opens the NaCl box ciphertext, which must be a value
|
|
// created by SealTo, and returns the inner cleartext if ciphertext is
|
|
// a valid box from p to k.
|
|
func (k NodePrivate) OpenFrom(p NodePublic, ciphertext []byte) (cleartext []byte, ok bool) {
|
|
if k.IsZero() || p.IsZero() {
|
|
panic("can't open with zero keys")
|
|
}
|
|
if len(ciphertext) < 24 {
|
|
return nil, false
|
|
}
|
|
nonce := (*[24]byte)(ciphertext)
|
|
return box.Open(nil, ciphertext[len(nonce):], nonce, &p.k, &k.k)
|
|
}
|
|
|
|
func (k NodePrivate) UntypedHexString() string {
|
|
return hex.EncodeToString(k.k[:])
|
|
}
|
|
|
|
// NodePublic is the public portion of a NodePrivate.
|
|
type NodePublic struct {
|
|
k [32]byte
|
|
}
|
|
|
|
// ParseNodePublicUntyped parses an untyped 64-character hex value
|
|
// as a NodePublic.
|
|
//
|
|
// Deprecated: this function is risky to use, because it cannot verify
|
|
// that the hex string was intended to be a NodePublic. This can
|
|
// lead to accidentally decoding one type of key as another. For new
|
|
// uses that don't require backwards compatibility with the untyped
|
|
// string format, please use MarshalText/UnmarshalText.
|
|
func ParseNodePublicUntyped(raw mem.RO) (NodePublic, error) {
|
|
var ret NodePublic
|
|
if err := parseHex(ret.k[:], raw, mem.B(nil)); err != nil {
|
|
return NodePublic{}, err
|
|
}
|
|
return ret, nil
|
|
}
|
|
|
|
// NodePublicFromRaw32 parses a 32-byte raw value as a NodePublic.
|
|
//
|
|
// This should be used only when deserializing a NodePublic from a
|
|
// binary protocol.
|
|
func NodePublicFromRaw32(raw mem.RO) NodePublic {
|
|
if raw.Len() != 32 {
|
|
panic("input has wrong size")
|
|
}
|
|
var ret NodePublic
|
|
raw.Copy(ret.k[:])
|
|
return ret
|
|
}
|
|
|
|
// IsZero reports whether k is the zero value.
|
|
func (k NodePublic) IsZero() bool {
|
|
return k == NodePublic{}
|
|
}
|
|
|
|
// ShortString returns the Tailscale conventional debug representation
|
|
// of a public key: the first five base64 digits of the key, in square
|
|
// brackets.
|
|
func (k NodePublic) ShortString() string {
|
|
return debug32(k.k)
|
|
}
|
|
|
|
// AppendTo appends k, serialized as a 32-byte binary value, to
|
|
// buf. Returns the new slice.
|
|
func (k NodePublic) AppendTo(buf []byte) []byte {
|
|
return append(buf, k.k[:]...)
|
|
}
|
|
|
|
// ReadRawWithoutAllocating initializes k with bytes read from br.
|
|
// The reading is done ~4x slower than io.ReadFull, but in exchange is
|
|
// allocation-free.
|
|
func (k *NodePublic) ReadRawWithoutAllocating(br *bufio.Reader) error {
|
|
var z NodePublic
|
|
if *k != z {
|
|
return errors.New("refusing to read into non-zero NodePublic")
|
|
}
|
|
// This is ~4x slower than io.ReadFull, but using io.ReadFull
|
|
// causes one extra alloc, which is significant for the DERP
|
|
// server that consumes this method. So, process stuff slower but
|
|
// without allocation.
|
|
//
|
|
// Dear future: if io.ReadFull stops causing stuff to escape, you
|
|
// should switch back to that.
|
|
for i := range k.k {
|
|
b, err := br.ReadByte()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
k.k[i] = b
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// WriteRawWithoutAllocating writes out k as 32 bytes to bw.
|
|
// The writing is done ~3x slower than bw.Write, but in exchange is
|
|
// allocation-free.
|
|
func (k NodePublic) WriteRawWithoutAllocating(bw *bufio.Writer) error {
|
|
// Equivalent to bw.Write(k.k[:]), but without causing an
|
|
// escape-related alloc.
|
|
//
|
|
// Dear future: if bw.Write(k.k[:]) stops causing stuff to escape,
|
|
// you should switch back to that.
|
|
for _, b := range k.k {
|
|
err := bw.WriteByte(b)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Raw32 returns k encoded as 32 raw bytes.
|
|
//
|
|
// Deprecated: only needed for a single legacy use in the control
|
|
// server, don't add more uses.
|
|
func (k NodePublic) Raw32() [32]byte {
|
|
var ret [32]byte
|
|
copy(ret[:], k.k[:])
|
|
return ret
|
|
}
|
|
|
|
// Less reports whether k orders before other, using an undocumented
|
|
// deterministic ordering.
|
|
func (k NodePublic) Less(other NodePublic) bool {
|
|
return bytes.Compare(k.k[:], other.k[:]) < 0
|
|
}
|
|
|
|
// UntypedHexString returns k, encoded as an untyped 64-character hex
|
|
// string.
|
|
//
|
|
// Deprecated: this function is risky to use, because it produces
|
|
// serialized values that do not identify themselves as a
|
|
// NodePublic, allowing other code to potentially parse it back in
|
|
// as the wrong key type. For new uses that don't require backwards
|
|
// compatibility with the untyped string format, please use
|
|
// MarshalText/UnmarshalText.
|
|
func (k NodePublic) UntypedHexString() string {
|
|
return hex.EncodeToString(k.k[:])
|
|
}
|
|
|
|
// String returns the output of MarshalText as a string.
|
|
func (k NodePublic) String() string {
|
|
bs, err := k.MarshalText()
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
return string(bs)
|
|
}
|
|
|
|
// MarshalText implements encoding.TextMarshaler.
|
|
func (k NodePublic) MarshalText() ([]byte, error) {
|
|
return toHex(k.k[:], nodePublicHexPrefix), nil
|
|
}
|
|
|
|
// MarshalText implements encoding.TextUnmarshaler.
|
|
func (k *NodePublic) UnmarshalText(b []byte) error {
|
|
return parseHex(k.k[:], mem.B(b), mem.S(nodePublicHexPrefix))
|
|
}
|
|
|
|
// WireGuardGoString prints k in the same format used by wireguard-go.
|
|
func (k NodePublic) WireGuardGoString() string {
|
|
// This implementation deliberately matches the overly complicated
|
|
// implementation in wireguard-go.
|
|
b64 := func(input byte) byte {
|
|
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)
|
|
}
|
|
b := []byte("peer(____…____)")
|
|
const first = len("peer(")
|
|
const second = len("peer(____…")
|
|
b[first+0] = b64((k.k[0] >> 2) & 63)
|
|
b[first+1] = b64(((k.k[0] << 4) | (k.k[1] >> 4)) & 63)
|
|
b[first+2] = b64(((k.k[1] << 2) | (k.k[2] >> 6)) & 63)
|
|
b[first+3] = b64(k.k[2] & 63)
|
|
b[second+0] = b64(k.k[29] & 63)
|
|
b[second+1] = b64((k.k[30] >> 2) & 63)
|
|
b[second+2] = b64(((k.k[30] << 4) | (k.k[31] >> 4)) & 63)
|
|
b[second+3] = b64((k.k[31] << 2) & 63)
|
|
return string(b)
|
|
}
|