github.com/Hnampk/fabric@v2.1.1+incompatible/cmd/common/signer/signer.go (about)

     1  /*
     2  Copyright IBM Corp. All Rights Reserved.
     3  
     4  SPDX-License-Identifier: Apache-2.0
     5  */
     6  
     7  package signer
     8  
     9  import (
    10  	"crypto"
    11  	"crypto/ecdsa"
    12  	"crypto/rand"
    13  	"crypto/x509"
    14  	"encoding/asn1"
    15  	"encoding/pem"
    16  	"io/ioutil"
    17  	"math/big"
    18  
    19  	"github.com/hyperledger/fabric-protos-go/msp"
    20  	"github.com/hyperledger/fabric/bccsp/utils"
    21  	"github.com/hyperledger/fabric/common/util"
    22  	"github.com/hyperledger/fabric/protoutil"
    23  	"github.com/pkg/errors"
    24  )
    25  
    26  // Config holds the configuration for
    27  // creation of a Signer
    28  type Config struct {
    29  	MSPID        string
    30  	IdentityPath string
    31  	KeyPath      string
    32  }
    33  
    34  // Signer signs messages.
    35  // TODO: Ideally we'd use an MSP to be agnostic, but since it's impossible to
    36  // initialize an MSP without a CA cert that signs the signing identity,
    37  // this will do for now.
    38  type Signer struct {
    39  	key     *ecdsa.PrivateKey
    40  	Creator []byte
    41  }
    42  
    43  func (si *Signer) Serialize() ([]byte, error) {
    44  	return si.Creator, nil
    45  }
    46  
    47  // NewSigner creates a new Signer out of the given configuration
    48  func NewSigner(conf Config) (*Signer, error) {
    49  	sId, err := serializeIdentity(conf.IdentityPath, conf.MSPID)
    50  	if err != nil {
    51  		return nil, errors.WithStack(err)
    52  	}
    53  	key, err := loadPrivateKey(conf.KeyPath)
    54  	if err != nil {
    55  		return nil, errors.WithStack(err)
    56  	}
    57  	return &Signer{
    58  		Creator: sId,
    59  		key:     key,
    60  	}, nil
    61  }
    62  
    63  func serializeIdentity(clientCert string, mspID string) ([]byte, error) {
    64  	b, err := ioutil.ReadFile(clientCert)
    65  	if err != nil {
    66  		return nil, errors.WithStack(err)
    67  	}
    68  	sId := &msp.SerializedIdentity{
    69  		Mspid:   mspID,
    70  		IdBytes: b,
    71  	}
    72  	return protoutil.MarshalOrPanic(sId), nil
    73  }
    74  
    75  func (si *Signer) Sign(msg []byte) ([]byte, error) {
    76  	digest := util.ComputeSHA256(msg)
    77  	return signECDSA(si.key, digest)
    78  }
    79  
    80  func loadPrivateKey(file string) (*ecdsa.PrivateKey, error) {
    81  	b, err := ioutil.ReadFile(file)
    82  	if err != nil {
    83  		return nil, errors.WithStack(err)
    84  	}
    85  	bl, _ := pem.Decode(b)
    86  	if bl == nil {
    87  		return nil, errors.Errorf("failed to decode PEM block from %s", file)
    88  	}
    89  	key, err := parsePrivateKey(bl.Bytes)
    90  	if err != nil {
    91  		return nil, err
    92  	}
    93  	return key.(*ecdsa.PrivateKey), nil
    94  }
    95  
    96  // Based on crypto/tls/tls.go but modified for Fabric:
    97  func parsePrivateKey(der []byte) (crypto.PrivateKey, error) {
    98  	// OpenSSL 1.0.0 generates PKCS#8 keys.
    99  	if key, err := x509.ParsePKCS8PrivateKey(der); err == nil {
   100  		switch key := key.(type) {
   101  		// Fabric only supports ECDSA at the moment.
   102  		case *ecdsa.PrivateKey:
   103  			return key, nil
   104  		default:
   105  			return nil, errors.Errorf("found unknown private key type (%T) in PKCS#8 wrapping", key)
   106  		}
   107  	}
   108  
   109  	// OpenSSL ecparam generates SEC1 EC private keys for ECDSA.
   110  	key, err := x509.ParseECPrivateKey(der)
   111  	if err != nil {
   112  		return nil, errors.Errorf("failed to parse private key: %v", err)
   113  	}
   114  
   115  	return key, nil
   116  }
   117  
   118  func signECDSA(k *ecdsa.PrivateKey, digest []byte) (signature []byte, err error) {
   119  	r, s, err := ecdsa.Sign(rand.Reader, k, digest)
   120  	if err != nil {
   121  		return nil, err
   122  	}
   123  
   124  	s, err = utils.ToLowS(&k.PublicKey, s)
   125  	if err != nil {
   126  		return nil, err
   127  	}
   128  
   129  	return marshalECDSASignature(r, s)
   130  }
   131  
   132  func marshalECDSASignature(r, s *big.Int) ([]byte, error) {
   133  	return asn1.Marshal(ECDSASignature{r, s})
   134  }
   135  
   136  type ECDSASignature struct {
   137  	R, S *big.Int
   138  }