github.com/titbtcqash/go-ethereum@v1.9.7/p2p/enode/idscheme.go (about)

     1  // Copyright 2018 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package enode
    18  
    19  import (
    20  	"crypto/ecdsa"
    21  	"fmt"
    22  	"io"
    23  
    24  	"github.com/ethereum/go-ethereum/common/math"
    25  	"github.com/ethereum/go-ethereum/crypto"
    26  	"github.com/ethereum/go-ethereum/p2p/enr"
    27  	"github.com/ethereum/go-ethereum/rlp"
    28  	"golang.org/x/crypto/sha3"
    29  )
    30  
    31  // List of known secure identity schemes.
    32  var ValidSchemes = enr.SchemeMap{
    33  	"v4": V4ID{},
    34  }
    35  
    36  var ValidSchemesForTesting = enr.SchemeMap{
    37  	"v4":   V4ID{},
    38  	"null": NullID{},
    39  }
    40  
    41  // v4ID is the "v4" identity scheme.
    42  type V4ID struct{}
    43  
    44  // SignV4 signs a record using the v4 scheme.
    45  func SignV4(r *enr.Record, privkey *ecdsa.PrivateKey) error {
    46  	// Copy r to avoid modifying it if signing fails.
    47  	cpy := *r
    48  	cpy.Set(enr.ID("v4"))
    49  	cpy.Set(Secp256k1(privkey.PublicKey))
    50  
    51  	h := sha3.NewLegacyKeccak256()
    52  	rlp.Encode(h, cpy.AppendElements(nil))
    53  	sig, err := crypto.Sign(h.Sum(nil), privkey)
    54  	if err != nil {
    55  		return err
    56  	}
    57  	sig = sig[:len(sig)-1] // remove v
    58  	if err = cpy.SetSig(V4ID{}, sig); err == nil {
    59  		*r = cpy
    60  	}
    61  	return err
    62  }
    63  
    64  func (V4ID) Verify(r *enr.Record, sig []byte) error {
    65  	var entry s256raw
    66  	if err := r.Load(&entry); err != nil {
    67  		return err
    68  	} else if len(entry) != 33 {
    69  		return fmt.Errorf("invalid public key")
    70  	}
    71  
    72  	h := sha3.NewLegacyKeccak256()
    73  	rlp.Encode(h, r.AppendElements(nil))
    74  	if !crypto.VerifySignature(entry, h.Sum(nil), sig) {
    75  		return enr.ErrInvalidSig
    76  	}
    77  	return nil
    78  }
    79  
    80  func (V4ID) NodeAddr(r *enr.Record) []byte {
    81  	var pubkey Secp256k1
    82  	err := r.Load(&pubkey)
    83  	if err != nil {
    84  		return nil
    85  	}
    86  	buf := make([]byte, 64)
    87  	math.ReadBits(pubkey.X, buf[:32])
    88  	math.ReadBits(pubkey.Y, buf[32:])
    89  	return crypto.Keccak256(buf)
    90  }
    91  
    92  // Secp256k1 is the "secp256k1" key, which holds a public key.
    93  type Secp256k1 ecdsa.PublicKey
    94  
    95  func (v Secp256k1) ENRKey() string { return "secp256k1" }
    96  
    97  // EncodeRLP implements rlp.Encoder.
    98  func (v Secp256k1) EncodeRLP(w io.Writer) error {
    99  	return rlp.Encode(w, crypto.CompressPubkey((*ecdsa.PublicKey)(&v)))
   100  }
   101  
   102  // DecodeRLP implements rlp.Decoder.
   103  func (v *Secp256k1) DecodeRLP(s *rlp.Stream) error {
   104  	buf, err := s.Bytes()
   105  	if err != nil {
   106  		return err
   107  	}
   108  	pk, err := crypto.DecompressPubkey(buf)
   109  	if err != nil {
   110  		return err
   111  	}
   112  	*v = (Secp256k1)(*pk)
   113  	return nil
   114  }
   115  
   116  // s256raw is an unparsed secp256k1 public key entry.
   117  type s256raw []byte
   118  
   119  func (s256raw) ENRKey() string { return "secp256k1" }
   120  
   121  // v4CompatID is a weaker and insecure version of the "v4" scheme which only checks for the
   122  // presence of a secp256k1 public key, but doesn't verify the signature.
   123  type v4CompatID struct {
   124  	V4ID
   125  }
   126  
   127  func (v4CompatID) Verify(r *enr.Record, sig []byte) error {
   128  	var pubkey Secp256k1
   129  	return r.Load(&pubkey)
   130  }
   131  
   132  func signV4Compat(r *enr.Record, pubkey *ecdsa.PublicKey) {
   133  	r.Set((*Secp256k1)(pubkey))
   134  	if err := r.SetSig(v4CompatID{}, []byte{}); err != nil {
   135  		panic(err)
   136  	}
   137  }
   138  
   139  // NullID is the "null" ENR identity scheme. This scheme stores the node
   140  // ID in the record without any signature.
   141  type NullID struct{}
   142  
   143  func (NullID) Verify(r *enr.Record, sig []byte) error {
   144  	return nil
   145  }
   146  
   147  func (NullID) NodeAddr(r *enr.Record) []byte {
   148  	var id ID
   149  	r.Load(enr.WithEntry("nulladdr", &id))
   150  	return id[:]
   151  }
   152  
   153  func SignNull(r *enr.Record, id ID) *Node {
   154  	r.Set(enr.ID("null"))
   155  	r.Set(enr.WithEntry("nulladdr", id))
   156  	if err := r.SetSig(NullID{}, []byte{}); err != nil {
   157  		panic(err)
   158  	}
   159  	return &Node{r: *r, id: id}
   160  }