/
csrf.go
197 lines (180 loc) · 5.13 KB
/
csrf.go
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// Copyright (c) 2021 Terminus, Inc.
//
// This program is free software: you can use, redistribute, and/or modify
// it under the terms of the GNU Affero General Public License, version 3
// or later ("AGPL"), as published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package prehandle
import (
"context"
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"encoding/hex"
"fmt"
"io"
"net/http"
"net/url"
"strconv"
"time"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"github.com/erda-project/erda/modules/openapi/conf"
"github.com/erda-project/erda/pkg/strutil"
)
var (
csrfTokenKey = "OPENAPI-CSRF-TOKEN"
csrfEncryptKey = []byte("OPENAPI!OPENAPI!OPENAPI!OPENAPI!") // 32 bytes
csrfExpire = 12 * time.Hour
csrfRefresh = 6 * time.Hour
)
func CSRFToken(ctx context.Context, rw http.ResponseWriter, req *http.Request) error {
if req.Header.Get("Referer") == "" {
return nil
}
r, err := url.Parse(req.Header.Get("Referer"))
if err == nil {
if strutil.HasSuffixes(r.Host, conf.CSRFWhiteList()...) {
return nil
}
}
csrftokenCookie, err := req.Cookie(csrfTokenKey)
if err != nil && (req.Method == "GET" || req.Method == "HEAD" || req.Method == "OPTIONS" || req.Method == "TRACE") {
// not exist csrftoken in cookie, set it
if err := setToken(rw, req); err != nil {
http.Error(rw, fmt.Sprintf("err set csrf token:%v", err), http.StatusInternalServerError)
return err
}
// if not exist csrftoken in cookie, then make it valid
return nil
} else if err != nil {
if err := setToken(rw, req); err != nil {
http.Error(rw, fmt.Sprintf("err set csrf token:%v", err), http.StatusInternalServerError)
return err
}
err := fmt.Errorf("empty csrf token")
http.Error(rw, err.Error(), http.StatusForbidden)
return err
} else {
t, err := validateCSRFToken(csrftokenCookie.Value)
if err != nil {
if err := setToken(rw, req); err != nil {
http.Error(rw, fmt.Sprintf("err set csrf token:%v", err), http.StatusInternalServerError)
return err
}
} else {
now := time.Now()
if now.After(t.Add(csrfRefresh * time.Hour)) {
if err := setToken(rw, req); err != nil {
http.Error(rw, fmt.Sprintf("err set csrf token:%v", err), http.StatusInternalServerError)
return err
}
}
}
}
if req.Method == "GET" || req.Method == "HEAD" || req.Method == "OPTIONS" || req.Method == "TRACE" {
return nil
}
// 非幂等method
csrftoken := req.Header.Get(csrfTokenKey)
if csrftoken == "" {
err := fmt.Errorf("empty csrf token")
http.Error(rw, err.Error(), http.StatusForbidden)
return err
}
if _, err := validateCSRFToken(csrftoken); err != nil {
logrus.Warnf("bad csrf token: %v", err)
http.Error(rw, "bad csrf token", http.StatusForbidden)
return err
}
return nil
}
func setToken(rw http.ResponseWriter, req *http.Request) error {
token, err := generateCSRFToken()
if err != nil {
return err
}
reqDomain, err := conf.GetDomain(req.Host, conf.CSRFCookieDomain())
if err != nil {
return err
}
http.SetCookie(rw, &http.Cookie{
Name: csrfTokenKey,
Value: token,
Path: "/",
Expires: time.Now().Add(csrfExpire),
Domain: reqDomain,
Secure: strutil.Contains(conf.DiceProtocol(), "https"),
})
return nil
}
func generateCSRFToken() (string, error) {
buf := make([]byte, 10)
_, err := rand.Read(buf)
if err != nil {
return "", err
}
content := append(buf, []byte(strconv.FormatInt(time.Now().Add(csrfExpire).Unix(), 10))...)
ciphertext, err := encrypt(content, csrfEncryptKey)
if err != nil {
return "", err
}
return hex.EncodeToString(ciphertext), nil
}
func validateCSRFToken(token string) (*time.Time, error) {
ciphertext, err := hex.DecodeString(token)
if err != nil {
return nil, err
}
decryptToken, err := decrypt(ciphertext, csrfEncryptKey)
if err != nil {
return nil, err
}
timestamp, err := strconv.ParseInt(string(decryptToken[10:]), 10, 64)
if err != nil {
return nil, err
}
t := time.Unix(timestamp, 0)
now := time.Now()
if t.After(now) && t.Before(now.Add(csrfExpire)) {
return &t, nil
}
return nil, fmt.Errorf("illegal csrf token")
}
func encrypt(plaintext []byte, key []byte) ([]byte, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(c)
if err != nil {
return nil, err
}
nonce := make([]byte, gcm.NonceSize())
if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
return nil, err
}
return gcm.Seal(nonce, nonce, plaintext, nil), nil
}
func decrypt(ciphertext []byte, key []byte) ([]byte, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(c)
if err != nil {
return nil, err
}
nonceSize := gcm.NonceSize()
if len(ciphertext) < nonceSize {
return nil, errors.New("ciphertext too short")
}
nonce, ciphertext := ciphertext[:nonceSize], ciphertext[nonceSize:]
return gcm.Open(nil, nonce, ciphertext, nil)
}