116 lines
2.9 KiB
Go
116 lines
2.9 KiB
Go
package jwt
|
|
|
|
import (
|
|
"crypto"
|
|
"crypto/rand"
|
|
"crypto/rsa"
|
|
"fmt"
|
|
)
|
|
|
|
// SigningMethodRSA implements the RSA family of signing methods signing methods
|
|
// Expects *rsa.PrivateKey for signing and *rsa.PublicKey for validation
|
|
type SigningMethodRSA struct {
|
|
Name string
|
|
Hash crypto.Hash
|
|
}
|
|
|
|
// Specific instances for RS256 and company
|
|
var (
|
|
SigningMethodRS256 *SigningMethodRSA
|
|
SigningMethodRS384 *SigningMethodRSA
|
|
SigningMethodRS512 *SigningMethodRSA
|
|
)
|
|
|
|
func init() {
|
|
// RS256
|
|
SigningMethodRS256 = &SigningMethodRSA{"RS256", crypto.SHA256}
|
|
RegisterSigningMethod(SigningMethodRS256.Alg(), func() SigningMethod {
|
|
return SigningMethodRS256
|
|
})
|
|
|
|
// RS384
|
|
SigningMethodRS384 = &SigningMethodRSA{"RS384", crypto.SHA384}
|
|
RegisterSigningMethod(SigningMethodRS384.Alg(), func() SigningMethod {
|
|
return SigningMethodRS384
|
|
})
|
|
|
|
// RS512
|
|
SigningMethodRS512 = &SigningMethodRSA{"RS512", crypto.SHA512}
|
|
RegisterSigningMethod(SigningMethodRS512.Alg(), func() SigningMethod {
|
|
return SigningMethodRS512
|
|
})
|
|
}
|
|
|
|
// Alg implements the Alg method from SigningMethod
|
|
func (m *SigningMethodRSA) Alg() string {
|
|
return m.Name
|
|
}
|
|
|
|
// Verify implements the Verify method from SigningMethod
|
|
// For this signing method, must be an *rsa.PublicKey structure.
|
|
func (m *SigningMethodRSA) Verify(signingString, signature string, key interface{}) error {
|
|
var err error
|
|
|
|
// Decode the signature
|
|
var sig []byte
|
|
if sig, err = DecodeSegment(signature); err != nil {
|
|
return err
|
|
}
|
|
|
|
var rsaKey *rsa.PublicKey
|
|
var ok bool
|
|
|
|
switch k := key.(type) {
|
|
case *rsa.PublicKey:
|
|
rsaKey = k
|
|
case crypto.Signer:
|
|
pub := k.Public()
|
|
if rsaKey, ok = pub.(*rsa.PublicKey); !ok {
|
|
return &InvalidKeyError{Message: fmt.Sprintf("signer returned unexpected public key type: %T", pub)}
|
|
}
|
|
default:
|
|
return NewInvalidKeyTypeError("*rsa.PublicKey or crypto.Signer", key)
|
|
}
|
|
|
|
// Create hasher
|
|
if !m.Hash.Available() {
|
|
return ErrHashUnavailable
|
|
}
|
|
hasher := m.Hash.New()
|
|
hasher.Write([]byte(signingString))
|
|
|
|
// Verify the signature
|
|
return rsa.VerifyPKCS1v15(rsaKey, m.Hash, hasher.Sum(nil), sig)
|
|
}
|
|
|
|
// Sign implements the Sign method from SigningMethod
|
|
// For this signing method, must be an *rsa.PrivateKey structure.
|
|
func (m *SigningMethodRSA) Sign(signingString string, key interface{}) (string, error) {
|
|
var signer crypto.Signer
|
|
var ok bool
|
|
|
|
if signer, ok = key.(crypto.Signer); !ok {
|
|
return "", NewInvalidKeyTypeError("*rsa.PublicKey or crypto.Signer", key)
|
|
}
|
|
|
|
//sanity check that the signer is an rsa signer
|
|
if pub, ok := signer.Public().(*rsa.PublicKey); !ok {
|
|
return "", &InvalidKeyError{Message: fmt.Sprintf("signer returned unexpected public key type: %T", pub)}
|
|
}
|
|
|
|
// Create the hasher
|
|
if !m.Hash.Available() {
|
|
return "", ErrHashUnavailable
|
|
}
|
|
|
|
hasher := m.Hash.New()
|
|
hasher.Write([]byte(signingString))
|
|
|
|
// Sign the string and return the encoded bytes
|
|
sigBytes, err := signer.Sign(rand.Reader, hasher.Sum(nil), m.Hash)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
return EncodeSegment(sigBytes), nil
|
|
}
|