syncthing/lib/api/api_auth.go
Jakob Borg ca89f12be6
lib/api: Set ServerName on LDAPS connections (fixes #6450) (#6451)
tls.Dial needs it for certificate verification.
2020-03-24 12:56:43 +01:00

183 lines
4.6 KiB
Go

// Copyright (C) 2014 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package api
import (
"bytes"
"crypto/tls"
"encoding/base64"
"fmt"
"net"
"net/http"
"strings"
"time"
"github.com/syncthing/syncthing/lib/config"
"github.com/syncthing/syncthing/lib/events"
"github.com/syncthing/syncthing/lib/rand"
"github.com/syncthing/syncthing/lib/sync"
"golang.org/x/crypto/bcrypt"
ldap "gopkg.in/ldap.v2"
)
var (
sessions = make(map[string]bool)
sessionsMut = sync.NewMutex()
)
func emitLoginAttempt(success bool, username string, evLogger events.Logger) {
evLogger.Log(events.LoginAttempt, map[string]interface{}{
"success": success,
"username": username,
})
}
func basicAuthAndSessionMiddleware(cookieName string, guiCfg config.GUIConfiguration, ldapCfg config.LDAPConfiguration, next http.Handler, evLogger events.Logger) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if guiCfg.IsValidAPIKey(r.Header.Get("X-API-Key")) {
next.ServeHTTP(w, r)
return
}
cookie, err := r.Cookie(cookieName)
if err == nil && cookie != nil {
sessionsMut.Lock()
_, ok := sessions[cookie.Value]
sessionsMut.Unlock()
if ok {
next.ServeHTTP(w, r)
return
}
}
l.Debugln("Sessionless HTTP request with authentication; this is expensive.")
error := func() {
time.Sleep(time.Duration(rand.Intn(100)+100) * time.Millisecond)
w.Header().Set("WWW-Authenticate", "Basic realm=\"Authorization Required\"")
http.Error(w, "Not Authorized", http.StatusUnauthorized)
}
hdr := r.Header.Get("Authorization")
if !strings.HasPrefix(hdr, "Basic ") {
error()
return
}
hdr = hdr[6:]
bs, err := base64.StdEncoding.DecodeString(hdr)
if err != nil {
error()
return
}
fields := bytes.SplitN(bs, []byte(":"), 2)
if len(fields) != 2 {
error()
return
}
username := string(fields[0])
password := string(fields[1])
authOk := auth(username, password, guiCfg, ldapCfg)
if !authOk {
usernameIso := string(iso88591ToUTF8([]byte(username)))
passwordIso := string(iso88591ToUTF8([]byte(password)))
authOk = auth(usernameIso, passwordIso, guiCfg, ldapCfg)
if authOk {
username = usernameIso
}
}
if !authOk {
emitLoginAttempt(false, username, evLogger)
error()
return
}
sessionid := rand.String(32)
sessionsMut.Lock()
sessions[sessionid] = true
sessionsMut.Unlock()
http.SetCookie(w, &http.Cookie{
Name: cookieName,
Value: sessionid,
MaxAge: 0,
})
emitLoginAttempt(true, username, evLogger)
next.ServeHTTP(w, r)
})
}
func auth(username string, password string, guiCfg config.GUIConfiguration, ldapCfg config.LDAPConfiguration) bool {
if guiCfg.AuthMode == config.AuthModeLDAP {
return authLDAP(username, password, ldapCfg)
} else {
return authStatic(username, password, guiCfg.User, guiCfg.Password)
}
}
func authStatic(username string, password string, configUser string, configPassword string) bool {
configPasswordBytes := []byte(configPassword)
passwordBytes := []byte(password)
return bcrypt.CompareHashAndPassword(configPasswordBytes, passwordBytes) == nil && username == configUser
}
func authLDAP(username string, password string, cfg config.LDAPConfiguration) bool {
address := cfg.Address
hostname, _, err := net.SplitHostPort(address)
if err != nil {
hostname = address
}
var connection *ldap.Conn
if cfg.Transport == config.LDAPTransportTLS {
connection, err = ldap.DialTLS("tcp", address, &tls.Config{
ServerName: hostname,
InsecureSkipVerify: cfg.InsecureSkipVerify,
})
} else {
connection, err = ldap.Dial("tcp", address)
}
if err != nil {
l.Warnln("LDAP Dial:", err)
return false
}
if cfg.Transport == config.LDAPTransportStartTLS {
err = connection.StartTLS(&tls.Config{InsecureSkipVerify: cfg.InsecureSkipVerify})
if err != nil {
l.Warnln("LDAP Start TLS:", err)
return false
}
}
defer connection.Close()
err = connection.Bind(fmt.Sprintf(cfg.BindDN, username), password)
if err != nil {
l.Warnln("LDAP Bind:", err)
return false
}
return true
}
// Convert an ISO-8859-1 encoded byte string to UTF-8. Works by the
// principle that ISO-8859-1 bytes are equivalent to unicode code points,
// that a rune slice is a list of code points, and that stringifying a slice
// of runes generates UTF-8 in Go.
func iso88591ToUTF8(s []byte) []byte {
runes := make([]rune, len(s))
for i := range s {
runes[i] = rune(s[i])
}
return []byte(string(runes))
}