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// Copyright 2014 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
// Package ldap provide functions & structure to query a LDAP ldap directory
// For now, it's mainly tested again an MS Active Directory service, see README.md for more information
package ldap
import (
"crypto/tls"
"fmt"
"strings"
"gopkg.in/ldap.v2"
"github.com/gogits/gogs/modules/log"
)
type SecurityProtocol int
// Note: new type must be added at the end of list to maintain compatibility.
const (
SECURITY_PROTOCOL_UNENCRYPTED SecurityProtocol = iota
SECURITY_PROTOCOL_LDAPS
SECURITY_PROTOCOL_START_TLS
)
// Basic LDAP authentication service
type Source struct {
Name string // canonical name (ie. corporate.ad)
Host string // LDAP host
Port int // port number
SecurityProtocol SecurityProtocol
SkipVerify bool
BindDN string // DN to bind with
BindPassword string // Bind DN password
UserBase string // Base search path for users
UserDN string // Template for the DN of the user for simple auth
AttributeUsername string // Username attribute
AttributeName string // First name attribute
AttributeSurname string // Surname attribute
AttributeMail string // E-mail attribute
AttributesInBind bool // fetch attributes in bind context (not user)
Filter string // Query filter to validate entry
AdminFilter string // Query filter to check if user is admin
Enabled bool // if this source is disabled
}
func (ls *Source) sanitizedUserQuery(username string) (string, bool) {
// See http://tools.ietf.org/search/rfc4515
badCharacters := "\x00()*\\"
if strings.ContainsAny(username, badCharacters) {
log.Debug("'%s' contains invalid query characters. Aborting.", username)
return "", false
}
return fmt.Sprintf(ls.Filter, username), true
}
func (ls *Source) sanitizedUserDN(username string) (string, bool) {
// See http://tools.ietf.org/search/rfc4514: "special characters"
badCharacters := "\x00()*\\,='\"#+;<> "
if strings.ContainsAny(username, badCharacters) {
log.Debug("'%s' contains invalid DN characters. Aborting.", username)
return "", false
}
return fmt.Sprintf(ls.UserDN, username), true
}
func (ls *Source) findUserDN(l *ldap.Conn, name string) (string, bool) {
log.Trace("Search for LDAP user: %s", name)
if ls.BindDN != "" && ls.BindPassword != "" {
err := l.Bind(ls.BindDN, ls.BindPassword)
if err != nil {
log.Debug("Failed to bind as BindDN[%s]: %v", ls.BindDN, err)
return "", false
}
log.Trace("Bound as BindDN %s", ls.BindDN)
} else {
log.Trace("Proceeding with anonymous LDAP search.")
}
// A search for the user.
userFilter, ok := ls.sanitizedUserQuery(name)
if !ok {
return "", false
}
log.Trace("Searching for DN using filter %s and base %s", userFilter, ls.UserBase)
search := ldap.NewSearchRequest(
ls.UserBase, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0,
false, userFilter, []string{}, nil)
// Ensure we found a user
sr, err := l.Search(search)
if err != nil || len(sr.Entries) < 1 {
log.Debug("Failed search using filter[%s]: %v", userFilter, err)
return "", false
} else if len(sr.Entries) > 1 {
log.Debug("Filter '%s' returned more than one user.", userFilter)
return "", false
}
userDN := sr.Entries[0].DN
if userDN == "" {
log.Error(4, "LDAP search was successful, but found no DN!")
return "", false
}
return userDN, true
}
func dial(ls *Source) (*ldap.Conn, error) {
log.Trace("Dialing LDAP with security protocol (%v) without verifying: %v", ls.SecurityProtocol, ls.SkipVerify)
tlsCfg := &tls.Config{
ServerName: ls.Host,
InsecureSkipVerify: ls.SkipVerify,
}
if ls.SecurityProtocol == SECURITY_PROTOCOL_LDAPS {
return ldap.DialTLS("tcp", fmt.Sprintf("%s:%d", ls.Host, ls.Port), tlsCfg)
}
conn, err := ldap.Dial("tcp", fmt.Sprintf("%s:%d", ls.Host, ls.Port))
if err != nil {
return nil, fmt.Errorf("Dial: %v", err)
}
if ls.SecurityProtocol == SECURITY_PROTOCOL_START_TLS {
if err = conn.StartTLS(tlsCfg); err != nil {
conn.Close()
return nil, fmt.Errorf("StartTLS: %v", err)
}
}
return conn, nil
}
func bindUser(l *ldap.Conn, userDN, passwd string) error {
log.Trace("Binding with userDN: %s", userDN)
err := l.Bind(userDN, passwd)
if err != nil {
log.Debug("LDAP auth. failed for %s, reason: %v", userDN, err)
return err
}
log.Trace("Bound successfully with userDN: %s", userDN)
return err
}
// searchEntry : search an LDAP source if an entry (name, passwd) is valid and in the specific filter
func (ls *Source) SearchEntry(name, passwd string, directBind bool) (string, string, string, string, bool, bool) {
l, err := dial(ls)
if err != nil {
log.Error(4, "LDAP Connect error, %s:%v", ls.Host, err)
ls.Enabled = false
return "", "", "", "", false, false
}
defer l.Close()
var userDN string
if directBind {
log.Trace("LDAP will bind directly via UserDN template: %s", ls.UserDN)
var ok bool
userDN, ok = ls.sanitizedUserDN(name)
if !ok {
return "", "", "", "", false, false
}
} else {
log.Trace("LDAP will use BindDN.")
var found bool
userDN, found = ls.findUserDN(l, name)
if !found {
return "", "", "", "", false, false
}
}
if directBind || !ls.AttributesInBind {
// binds user (checking password) before looking-up attributes in user context
err = bindUser(l, userDN, passwd)
if err != nil {
return "", "", "", "", false, false
}
}
userFilter, ok := ls.sanitizedUserQuery(name)
if !ok {
return "", "", "", "", false, false
}
log.Trace("Fetching attributes '%v', '%v', '%v', '%v' with filter %s and base %s", ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail, userFilter, userDN)
search := ldap.NewSearchRequest(
userDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, userFilter,
[]string{ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail},
nil)
sr, err := l.Search(search)
if err != nil {
log.Error(4, "LDAP Search failed unexpectedly! (%v)", err)
return "", "", "", "", false, false
} else if len(sr.Entries) < 1 {
if directBind {
log.Error(4, "User filter inhibited user login.")
} else {
log.Error(4, "LDAP Search failed unexpectedly! (0 entries)")
}
return "", "", "", "", false, false
}
username := sr.Entries[0].GetAttributeValue(ls.AttributeUsername)
firstname := sr.Entries[0].GetAttributeValue(ls.AttributeName)
surname := sr.Entries[0].GetAttributeValue(ls.AttributeSurname)
mail := sr.Entries[0].GetAttributeValue(ls.AttributeMail)
isAdmin := false
if len(ls.AdminFilter) > 0 {
log.Trace("Checking admin with filter %s and base %s", ls.AdminFilter, userDN)
search = ldap.NewSearchRequest(
userDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, ls.AdminFilter,
[]string{ls.AttributeName},
nil)
sr, err = l.Search(search)
if err != nil {
log.Error(4, "LDAP Admin Search failed unexpectedly! (%v)", err)
} else if len(sr.Entries) < 1 {
log.Error(4, "LDAP Admin Search failed")
} else {
isAdmin = true
}
}
if !directBind && ls.AttributesInBind {
// binds user (checking password) after looking-up attributes in BindDN context
err = bindUser(l, userDN, passwd)
if err != nil {
return "", "", "", "", false, false
}
}
return username, firstname, surname, mail, isAdmin, true
}
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