Files
opencloud/vendor/github.com/libregraph/oidc-go/code.go
2023-04-19 20:24:34 +02:00

75 lines
2.3 KiB
Go

/*
* Copyright 2019 Kopano
*
* 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.
*/
package oidc
import (
"crypto/sha256"
"crypto/subtle"
"encoding/base64"
"errors"
)
// Code challenge methods implemented by Konnect. See https://tools.ietf.org/html/rfc7636.
const (
PlainCodeChallengeMethod = "plain"
S256CodeChallengeMethod = "S256"
)
// ValidateCodeChallenge implements https://tools.ietf.org/html/rfc7636#section-4.6
// code challenge verification.
func ValidateCodeChallenge(challenge string, method string, verifier string) error {
if method == "" {
// We default to S256CodeChallengeMethod.
method = S256CodeChallengeMethod
}
computed, err := MakeCodeChallenge(method, verifier)
if err != nil {
return err
}
if subtle.ConstantTimeCompare([]byte(challenge), []byte(computed)) != 1 {
return errors.New("invalid code challenge")
}
return nil
}
// MakeCodeChallenge creates a code challenge using the provided method and
// verifier for https://tools.ietf.org/html/rfc7636#section-4.6 verification.
func MakeCodeChallenge(method string, verifier string) (string, error) {
if verifier == "" {
return "", errors.New("invalid verifier")
}
switch method {
case PlainCodeChallengeMethod:
// Challenge is verifier.
return verifier, nil
case S256CodeChallengeMethod:
// BASE64URL-ENCODE(SHA256(ASCII(code_verifier)))
// Base64 encoding using the URL- and filename-safe character set
// defined in Section 5 of [RFC4648], with all trailing '='
// characters omitted (as permitted by Section 3.2 of [RFC4648]) and
// without the inclusion of any line breaks, whitespace, or other
// additional characters.
sum := sha256.Sum256([]byte(verifier))
return base64.RawURLEncoding.EncodeToString(sum[:]), nil
}
return "", errors.New("transform algorithm not supported")
}