mirror of https://github.com/hashicorp/consul
118 lines
2.9 KiB
Go
118 lines
2.9 KiB
Go
package crypto
|
|
|
|
import (
|
|
"crypto"
|
|
"crypto/ecdsa"
|
|
"crypto/rand"
|
|
"encoding/asn1"
|
|
"encoding/json"
|
|
"errors"
|
|
"math/big"
|
|
)
|
|
|
|
// ErrECDSAVerification is missing from crypto/ecdsa compared to crypto/rsa
|
|
var ErrECDSAVerification = errors.New("crypto/ecdsa: verification error")
|
|
|
|
// SigningMethodECDSA implements the ECDSA family of signing methods signing
|
|
// methods
|
|
type SigningMethodECDSA struct {
|
|
Name string
|
|
Hash crypto.Hash
|
|
_ struct{}
|
|
}
|
|
|
|
// ECPoint is a marshalling structure for the EC points R and S.
|
|
type ECPoint struct {
|
|
R *big.Int
|
|
S *big.Int
|
|
}
|
|
|
|
// Specific instances of EC SigningMethods.
|
|
var (
|
|
// SigningMethodES256 implements ES256.
|
|
SigningMethodES256 = &SigningMethodECDSA{
|
|
Name: "ES256",
|
|
Hash: crypto.SHA256,
|
|
}
|
|
|
|
// SigningMethodES384 implements ES384.
|
|
SigningMethodES384 = &SigningMethodECDSA{
|
|
Name: "ES384",
|
|
Hash: crypto.SHA384,
|
|
}
|
|
|
|
// SigningMethodES512 implements ES512.
|
|
SigningMethodES512 = &SigningMethodECDSA{
|
|
Name: "ES512",
|
|
Hash: crypto.SHA512,
|
|
}
|
|
)
|
|
|
|
// Alg returns the name of the SigningMethodECDSA instance.
|
|
func (m *SigningMethodECDSA) Alg() string { return m.Name }
|
|
|
|
// Verify implements the Verify method from SigningMethod.
|
|
// For this verify method, key must be an *ecdsa.PublicKey.
|
|
func (m *SigningMethodECDSA) Verify(raw []byte, signature Signature, key interface{}) error {
|
|
|
|
ecdsaKey, ok := key.(*ecdsa.PublicKey)
|
|
if !ok {
|
|
return ErrInvalidKey
|
|
}
|
|
|
|
// Unmarshal asn1 ECPoint
|
|
var ecpoint ECPoint
|
|
if _, err := asn1.Unmarshal(signature, &ecpoint); err != nil {
|
|
return err
|
|
}
|
|
|
|
// Verify the signature
|
|
if !ecdsa.Verify(ecdsaKey, m.sum(raw), ecpoint.R, ecpoint.S) {
|
|
return ErrECDSAVerification
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Sign implements the Sign method from SigningMethod.
|
|
// For this signing method, key must be an *ecdsa.PrivateKey.
|
|
func (m *SigningMethodECDSA) Sign(data []byte, key interface{}) (Signature, error) {
|
|
|
|
ecdsaKey, ok := key.(*ecdsa.PrivateKey)
|
|
if !ok {
|
|
return nil, ErrInvalidKey
|
|
}
|
|
|
|
r, s, err := ecdsa.Sign(rand.Reader, ecdsaKey, m.sum(data))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
signature, err := asn1.Marshal(ECPoint{R: r, S: s})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return Signature(signature), nil
|
|
}
|
|
|
|
func (m *SigningMethodECDSA) sum(b []byte) []byte {
|
|
h := m.Hash.New()
|
|
h.Write(b)
|
|
return h.Sum(nil)
|
|
}
|
|
|
|
// Hasher implements the Hasher method from SigningMethod.
|
|
func (m *SigningMethodECDSA) Hasher() crypto.Hash {
|
|
return m.Hash
|
|
}
|
|
|
|
// MarshalJSON is in case somebody decides to place SigningMethodECDSA
|
|
// inside the Header, presumably because they (wrongly) decided it was a good
|
|
// idea to use the SigningMethod itself instead of the SigningMethod's Alg
|
|
// method. In order to keep things sane, marshalling this will simply
|
|
// return the JSON-compatible representation of m.Alg().
|
|
func (m *SigningMethodECDSA) MarshalJSON() ([]byte, error) {
|
|
return []byte(`"` + m.Alg() + `"`), nil
|
|
}
|
|
|
|
var _ json.Marshaler = (*SigningMethodECDSA)(nil)
|