161 lines
4.0 KiB
Go
161 lines
4.0 KiB
Go
// Copyright 2018 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package enode
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import (
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"crypto/ecdsa"
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"fmt"
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"io"
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"github.com/ethereum/go-ethereum/common/math"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/crypto/sha3"
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"github.com/ethereum/go-ethereum/p2p/enr"
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"github.com/ethereum/go-ethereum/rlp"
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)
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// List of known secure identity schemes.
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var ValidSchemes = enr.SchemeMap{
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"v4": V4ID{},
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}
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var ValidSchemesForTesting = enr.SchemeMap{
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"v4": V4ID{},
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"null": NullID{},
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}
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// v4ID is the "v4" identity scheme.
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type V4ID struct{}
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// SignV4 signs a record using the v4 scheme.
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func SignV4(r *enr.Record, privkey *ecdsa.PrivateKey) error {
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// Copy r to avoid modifying it if signing fails.
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cpy := *r
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cpy.Set(enr.ID("v4"))
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cpy.Set(Secp256k1(privkey.PublicKey))
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h := sha3.NewKeccak256()
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rlp.Encode(h, cpy.AppendElements(nil))
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sig, err := crypto.Sign(h.Sum(nil), privkey)
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if err != nil {
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return err
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}
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sig = sig[:len(sig)-1] // remove v
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if err = cpy.SetSig(V4ID{}, sig); err == nil {
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*r = cpy
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}
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return err
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}
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func (V4ID) Verify(r *enr.Record, sig []byte) error {
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var entry s256raw
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if err := r.Load(&entry); err != nil {
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return err
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} else if len(entry) != 33 {
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return fmt.Errorf("invalid public key")
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}
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h := sha3.NewKeccak256()
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rlp.Encode(h, r.AppendElements(nil))
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if !crypto.VerifySignature(entry, h.Sum(nil), sig) {
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return enr.ErrInvalidSig
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}
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return nil
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}
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func (V4ID) NodeAddr(r *enr.Record) []byte {
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var pubkey Secp256k1
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err := r.Load(&pubkey)
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if err != nil {
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return nil
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}
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buf := make([]byte, 64)
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math.ReadBits(pubkey.X, buf[:32])
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math.ReadBits(pubkey.Y, buf[32:])
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return crypto.Keccak256(buf)
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}
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// Secp256k1 is the "secp256k1" key, which holds a public key.
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type Secp256k1 ecdsa.PublicKey
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func (v Secp256k1) ENRKey() string { return "secp256k1" }
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// EncodeRLP implements rlp.Encoder.
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func (v Secp256k1) EncodeRLP(w io.Writer) error {
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return rlp.Encode(w, crypto.CompressPubkey((*ecdsa.PublicKey)(&v)))
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}
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// DecodeRLP implements rlp.Decoder.
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func (v *Secp256k1) DecodeRLP(s *rlp.Stream) error {
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buf, err := s.Bytes()
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if err != nil {
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return err
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}
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pk, err := crypto.DecompressPubkey(buf)
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if err != nil {
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return err
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}
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*v = (Secp256k1)(*pk)
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return nil
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}
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// s256raw is an unparsed secp256k1 public key entry.
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type s256raw []byte
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func (s256raw) ENRKey() string { return "secp256k1" }
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// v4CompatID is a weaker and insecure version of the "v4" scheme which only checks for the
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// presence of a secp256k1 public key, but doesn't verify the signature.
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type v4CompatID struct {
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V4ID
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}
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func (v4CompatID) Verify(r *enr.Record, sig []byte) error {
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var pubkey Secp256k1
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return r.Load(&pubkey)
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}
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func signV4Compat(r *enr.Record, pubkey *ecdsa.PublicKey) {
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r.Set((*Secp256k1)(pubkey))
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if err := r.SetSig(v4CompatID{}, []byte{}); err != nil {
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panic(err)
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}
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}
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// NullID is the "null" ENR identity scheme. This scheme stores the node
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// ID in the record without any signature.
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type NullID struct{}
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func (NullID) Verify(r *enr.Record, sig []byte) error {
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return nil
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}
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func (NullID) NodeAddr(r *enr.Record) []byte {
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var id ID
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r.Load(enr.WithEntry("nulladdr", &id))
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return id[:]
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}
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func SignNull(r *enr.Record, id ID) *Node {
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r.Set(enr.ID("null"))
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r.Set(enr.WithEntry("nulladdr", id))
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if err := r.SetSig(NullID{}, []byte{}); err != nil {
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panic(err)
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}
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return &Node{r: *r, id: id}
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}
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