forked from ory/fosite
/
jwt.go
137 lines (116 loc) · 4.09 KB
/
jwt.go
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/*
* Copyright © 2015-2018 Aeneas Rekkas <aeneas+oss@aeneas.io>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* @author Aeneas Rekkas <aeneas+oss@aeneas.io>
* @copyright 2015-2018 Aeneas Rekkas <aeneas+oss@aeneas.io>
* @license Apache-2.0
*
*/
// Package jwt is able to generate and validate json web tokens.
// Follows https://tools.ietf.org/html/draft-ietf-oauth-json-web-token-32
package jwt
import (
"crypto/rsa"
"crypto/sha256"
"fmt"
"strings"
"context"
"github.com/dgrijalva/jwt-go"
"github.com/ory/fosite"
"github.com/pkg/errors"
)
type JWTStrategy interface {
Generate(ctx context.Context, claims jwt.Claims, header Mapper) (string, string, error)
Validate(ctx context.Context, token string) (string, error)
Hash(ctx context.Context, in []byte) ([]byte, error)
Decode(ctx context.Context, token string) (*jwt.Token, error)
GetSignature(ctx context.Context, token string) (string, error)
GetSigningMethodLength() int
}
// RS256JWTStrategy is responsible for generating and validating JWT challenges
type RS256JWTStrategy struct {
PrivateKey *rsa.PrivateKey
}
// Generate generates a new authorize code or returns an error. set secret
func (j *RS256JWTStrategy) Generate(ctx context.Context, claims jwt.Claims, header Mapper) (string, string, error) {
if header == nil || claims == nil {
return "", "", errors.New("Either claims or header is nil.")
}
token := jwt.NewWithClaims(jwt.SigningMethodRS256, claims)
token.Header = assign(token.Header, header.ToMap())
var sig, sstr string
var err error
if sstr, err = token.SigningString(); err != nil {
return "", "", errors.WithStack(err)
}
if sig, err = token.Method.Sign(sstr, j.PrivateKey); err != nil {
return "", "", errors.WithStack(err)
}
return fmt.Sprintf("%s.%s", sstr, sig), sig, nil
}
// Validate validates a token and returns its signature or an error if the token is not valid.
func (j *RS256JWTStrategy) Validate(ctx context.Context, token string) (string, error) {
if _, err := j.Decode(ctx, token); err != nil {
return "", errors.WithStack(err)
}
return j.GetSignature(ctx, token)
}
// Decode will decode a JWT token
func (j *RS256JWTStrategy) Decode(ctx context.Context, token string) (*jwt.Token, error) {
// Parse the token.
parsedToken, err := jwt.Parse(token, func(t *jwt.Token) (interface{}, error) {
if _, ok := t.Method.(*jwt.SigningMethodRSA); !ok {
return nil, errors.Errorf("Unexpected signing method: %v", t.Header["alg"])
}
return &j.PrivateKey.PublicKey, nil
})
if err != nil {
return parsedToken, errors.WithStack(err)
} else if !parsedToken.Valid {
return parsedToken, errors.WithStack(fosite.ErrInactiveToken)
}
return parsedToken, err
}
// GetSignature will return the signature of a token
func (j *RS256JWTStrategy) GetSignature(ctx context.Context, token string) (string, error) {
split := strings.Split(token, ".")
if len(split) != 3 {
return "", errors.New("Header, body and signature must all be set")
}
return split[2], nil
}
// Hash will return a given hash based on the byte input or an error upon fail
func (j *RS256JWTStrategy) Hash(ctx context.Context, in []byte) ([]byte, error) {
// SigningMethodRS256
hash := sha256.New()
_, err := hash.Write(in)
if err != nil {
return []byte{}, errors.WithStack(err)
}
return hash.Sum([]byte{}), nil
}
// GetSigningMethodLength will return the length of the signing method
func (j *RS256JWTStrategy) GetSigningMethodLength() int {
return jwt.SigningMethodRS256.Hash.Size()
}
func assign(a, b map[string]interface{}) map[string]interface{} {
for k, w := range b {
if _, ok := a[k]; ok {
continue
}
a[k] = w
}
return a
}