mirror of
https://codeberg.org/forgejo/forgejo.git
synced 2024-12-23 12:59:11 -05:00
97 lines
3.2 KiB
Go
97 lines
3.2 KiB
Go
// Copyright 2012 Google Inc. All Rights Reserved.
|
|
// Copyright 2014 The Macaron Authors
|
|
//
|
|
// 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 csrf
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/hmac"
|
|
"crypto/sha1"
|
|
"crypto/subtle"
|
|
"encoding/base64"
|
|
"fmt"
|
|
"strconv"
|
|
"strings"
|
|
"time"
|
|
)
|
|
|
|
// The duration that XSRF tokens are valid.
|
|
// It is exported so clients may set cookie timeouts that match generated tokens.
|
|
const TIMEOUT = 24 * time.Hour
|
|
|
|
// clean sanitizes a string for inclusion in a token by replacing all ":"s.
|
|
func clean(s string) string {
|
|
return strings.Replace(s, ":", "_", -1)
|
|
}
|
|
|
|
// GenerateToken returns a URL-safe secure XSRF token that expires in 24 hours.
|
|
//
|
|
// key is a secret key for your application.
|
|
// userID is a unique identifier for the user.
|
|
// actionID is the action the user is taking (e.g. POSTing to a particular path).
|
|
func GenerateToken(key, userID, actionID string) string {
|
|
return generateTokenAtTime(key, userID, actionID, time.Now())
|
|
}
|
|
|
|
// generateTokenAtTime is like Generate, but returns a token that expires 24 hours from now.
|
|
func generateTokenAtTime(key, userID, actionID string, now time.Time) string {
|
|
h := hmac.New(sha1.New, []byte(key))
|
|
fmt.Fprintf(h, "%s:%s:%d", clean(userID), clean(actionID), now.UnixNano())
|
|
tok := fmt.Sprintf("%s:%d", h.Sum(nil), now.UnixNano())
|
|
return base64.RawURLEncoding.EncodeToString([]byte(tok))
|
|
}
|
|
|
|
// Valid returns true if token is a valid, unexpired token returned by Generate.
|
|
func ValidToken(token, key, userID, actionID string) bool {
|
|
return validTokenAtTime(token, key, userID, actionID, time.Now())
|
|
}
|
|
|
|
// validTokenAtTime is like Valid, but it uses now to check if the token is expired.
|
|
func validTokenAtTime(token, key, userID, actionID string, now time.Time) bool {
|
|
// Decode the token.
|
|
data, err := base64.RawURLEncoding.DecodeString(token)
|
|
if err != nil {
|
|
return false
|
|
}
|
|
|
|
// Extract the issue time of the token.
|
|
sep := bytes.LastIndex(data, []byte{':'})
|
|
if sep < 0 {
|
|
return false
|
|
}
|
|
nanos, err := strconv.ParseInt(string(data[sep+1:]), 10, 64)
|
|
if err != nil {
|
|
return false
|
|
}
|
|
issueTime := time.Unix(0, nanos)
|
|
|
|
// Check that the token is not expired.
|
|
if now.Sub(issueTime) >= TIMEOUT {
|
|
return false
|
|
}
|
|
|
|
// Check that the token is not from the future.
|
|
// Allow 1 minute grace period in case the token is being verified on a
|
|
// machine whose clock is behind the machine that issued the token.
|
|
if issueTime.After(now.Add(1 * time.Minute)) {
|
|
return false
|
|
}
|
|
|
|
expected := generateTokenAtTime(key, userID, actionID, issueTime)
|
|
|
|
// Check that the token matches the expected value.
|
|
// Use constant time comparison to avoid timing attacks.
|
|
return subtle.ConstantTimeCompare([]byte(token), []byte(expected)) == 1
|
|
}
|