372 lines
11 KiB
Go
372 lines
11 KiB
Go
// Copyright 2014 The Gogs Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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// Package ldap provide functions & structure to query a LDAP ldap directory
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// For now, it's mainly tested again an MS Active Directory service, see README.md for more information
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package ldap
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import (
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"crypto/tls"
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"fmt"
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"strings"
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"code.gitea.io/gitea/modules/log"
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ldap "gopkg.in/ldap.v3"
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)
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// SecurityProtocol protocol type
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type SecurityProtocol int
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// Note: new type must be added at the end of list to maintain compatibility.
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const (
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SecurityProtocolUnencrypted SecurityProtocol = iota
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SecurityProtocolLDAPS
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SecurityProtocolStartTLS
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)
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// Source Basic LDAP authentication service
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type Source struct {
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Name string // canonical name (ie. corporate.ad)
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Host string // LDAP host
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Port int // port number
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SecurityProtocol SecurityProtocol
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SkipVerify bool
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BindDN string // DN to bind with
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BindPassword string // Bind DN password
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UserBase string // Base search path for users
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UserDN string // Template for the DN of the user for simple auth
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AttributeUsername string // Username attribute
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AttributeName string // First name attribute
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AttributeSurname string // Surname attribute
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AttributeMail string // E-mail attribute
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AttributesInBind bool // fetch attributes in bind context (not user)
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AttributeSSHPublicKey string // LDAP SSH Public Key attribute
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SearchPageSize uint32 // Search with paging page size
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Filter string // Query filter to validate entry
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AdminFilter string // Query filter to check if user is admin
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Enabled bool // if this source is disabled
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}
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// SearchResult : user data
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type SearchResult struct {
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Username string // Username
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Name string // Name
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Surname string // Surname
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Mail string // E-mail address
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SSHPublicKey []string // SSH Public Key
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IsAdmin bool // if user is administrator
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}
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func (ls *Source) sanitizedUserQuery(username string) (string, bool) {
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// See http://tools.ietf.org/search/rfc4515
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badCharacters := "\x00()*\\"
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if strings.ContainsAny(username, badCharacters) {
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log.Debug("'%s' contains invalid query characters. Aborting.", username)
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return "", false
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}
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return fmt.Sprintf(ls.Filter, username), true
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}
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func (ls *Source) sanitizedUserDN(username string) (string, bool) {
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// See http://tools.ietf.org/search/rfc4514: "special characters"
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badCharacters := "\x00()*\\,='\"#+;<>"
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if strings.ContainsAny(username, badCharacters) {
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log.Debug("'%s' contains invalid DN characters. Aborting.", username)
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return "", false
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}
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return fmt.Sprintf(ls.UserDN, username), true
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}
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func (ls *Source) findUserDN(l *ldap.Conn, name string) (string, bool) {
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log.Trace("Search for LDAP user: %s", name)
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// A search for the user.
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userFilter, ok := ls.sanitizedUserQuery(name)
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if !ok {
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return "", false
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}
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log.Trace("Searching for DN using filter %s and base %s", userFilter, ls.UserBase)
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search := ldap.NewSearchRequest(
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ls.UserBase, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0,
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false, userFilter, []string{}, nil)
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// Ensure we found a user
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sr, err := l.Search(search)
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if err != nil || len(sr.Entries) < 1 {
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log.Debug("Failed search using filter[%s]: %v", userFilter, err)
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return "", false
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} else if len(sr.Entries) > 1 {
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log.Debug("Filter '%s' returned more than one user.", userFilter)
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return "", false
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}
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userDN := sr.Entries[0].DN
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if userDN == "" {
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log.Error("LDAP search was successful, but found no DN!")
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return "", false
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}
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return userDN, true
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}
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func dial(ls *Source) (*ldap.Conn, error) {
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log.Trace("Dialing LDAP with security protocol (%v) without verifying: %v", ls.SecurityProtocol, ls.SkipVerify)
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tlsCfg := &tls.Config{
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ServerName: ls.Host,
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InsecureSkipVerify: ls.SkipVerify,
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}
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if ls.SecurityProtocol == SecurityProtocolLDAPS {
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return ldap.DialTLS("tcp", fmt.Sprintf("%s:%d", ls.Host, ls.Port), tlsCfg)
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}
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conn, err := ldap.Dial("tcp", fmt.Sprintf("%s:%d", ls.Host, ls.Port))
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if err != nil {
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return nil, fmt.Errorf("Dial: %v", err)
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}
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if ls.SecurityProtocol == SecurityProtocolStartTLS {
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if err = conn.StartTLS(tlsCfg); err != nil {
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conn.Close()
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return nil, fmt.Errorf("StartTLS: %v", err)
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}
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}
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return conn, nil
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}
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func bindUser(l *ldap.Conn, userDN, passwd string) error {
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log.Trace("Binding with userDN: %s", userDN)
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err := l.Bind(userDN, passwd)
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if err != nil {
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log.Debug("LDAP auth. failed for %s, reason: %v", userDN, err)
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return err
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}
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log.Trace("Bound successfully with userDN: %s", userDN)
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return err
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}
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func checkAdmin(l *ldap.Conn, ls *Source, userDN string) bool {
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if len(ls.AdminFilter) > 0 {
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log.Trace("Checking admin with filter %s and base %s", ls.AdminFilter, userDN)
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search := ldap.NewSearchRequest(
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userDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, ls.AdminFilter,
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[]string{ls.AttributeName},
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nil)
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sr, err := l.Search(search)
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if err != nil {
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log.Error("LDAP Admin Search failed unexpectedly! (%v)", err)
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} else if len(sr.Entries) < 1 {
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log.Trace("LDAP Admin Search found no matching entries.")
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} else {
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return true
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}
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}
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return false
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}
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// SearchEntry : search an LDAP source if an entry (name, passwd) is valid and in the specific filter
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func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResult {
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// See https://tools.ietf.org/search/rfc4513#section-5.1.2
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if len(passwd) == 0 {
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log.Debug("Auth. failed for %s, password cannot be empty", name)
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return nil
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}
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l, err := dial(ls)
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if err != nil {
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log.Error("LDAP Connect error, %s:%v", ls.Host, err)
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ls.Enabled = false
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return nil
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}
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defer l.Close()
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var userDN string
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if directBind {
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log.Trace("LDAP will bind directly via UserDN template: %s", ls.UserDN)
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var ok bool
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userDN, ok = ls.sanitizedUserDN(name)
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if !ok {
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return nil
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}
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err = bindUser(l, userDN, passwd)
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if err != nil {
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return nil
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}
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if ls.UserBase != "" {
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// not everyone has a CN compatible with input name so we need to find
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// the real userDN in that case
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userDN, ok = ls.findUserDN(l, name)
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if !ok {
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return nil
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}
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}
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} else {
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log.Trace("LDAP will use BindDN.")
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var found bool
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if ls.BindDN != "" && ls.BindPassword != "" {
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err := l.Bind(ls.BindDN, ls.BindPassword)
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if err != nil {
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log.Debug("Failed to bind as BindDN[%s]: %v", ls.BindDN, err)
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return nil
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}
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log.Trace("Bound as BindDN %s", ls.BindDN)
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} else {
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log.Trace("Proceeding with anonymous LDAP search.")
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}
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userDN, found = ls.findUserDN(l, name)
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if !found {
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return nil
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}
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}
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if !ls.AttributesInBind {
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// binds user (checking password) before looking-up attributes in user context
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err = bindUser(l, userDN, passwd)
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if err != nil {
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return nil
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}
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}
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userFilter, ok := ls.sanitizedUserQuery(name)
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if !ok {
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return nil
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}
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var isAttributeSSHPublicKeySet = len(strings.TrimSpace(ls.AttributeSSHPublicKey)) > 0
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attribs := []string{ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail}
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if isAttributeSSHPublicKeySet {
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attribs = append(attribs, ls.AttributeSSHPublicKey)
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}
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log.Trace("Fetching attributes '%v', '%v', '%v', '%v', '%v' with filter %s and base %s", ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail, ls.AttributeSSHPublicKey, userFilter, userDN)
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search := ldap.NewSearchRequest(
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userDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, userFilter,
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attribs, nil)
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sr, err := l.Search(search)
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if err != nil {
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log.Error("LDAP Search failed unexpectedly! (%v)", err)
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return nil
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} else if len(sr.Entries) < 1 {
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if directBind {
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log.Trace("User filter inhibited user login.")
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} else {
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log.Trace("LDAP Search found no matching entries.")
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}
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return nil
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}
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var sshPublicKey []string
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username := sr.Entries[0].GetAttributeValue(ls.AttributeUsername)
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firstname := sr.Entries[0].GetAttributeValue(ls.AttributeName)
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surname := sr.Entries[0].GetAttributeValue(ls.AttributeSurname)
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mail := sr.Entries[0].GetAttributeValue(ls.AttributeMail)
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if isAttributeSSHPublicKeySet {
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sshPublicKey = sr.Entries[0].GetAttributeValues(ls.AttributeSSHPublicKey)
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}
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isAdmin := checkAdmin(l, ls, userDN)
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if !directBind && ls.AttributesInBind {
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// binds user (checking password) after looking-up attributes in BindDN context
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err = bindUser(l, userDN, passwd)
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if err != nil {
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return nil
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}
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}
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return &SearchResult{
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Username: username,
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Name: firstname,
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Surname: surname,
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Mail: mail,
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SSHPublicKey: sshPublicKey,
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IsAdmin: isAdmin,
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}
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}
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// UsePagedSearch returns if need to use paged search
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func (ls *Source) UsePagedSearch() bool {
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return ls.SearchPageSize > 0
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}
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// SearchEntries : search an LDAP source for all users matching userFilter
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func (ls *Source) SearchEntries() ([]*SearchResult, error) {
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l, err := dial(ls)
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if err != nil {
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log.Error("LDAP Connect error, %s:%v", ls.Host, err)
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ls.Enabled = false
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return nil, err
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}
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defer l.Close()
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if ls.BindDN != "" && ls.BindPassword != "" {
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err := l.Bind(ls.BindDN, ls.BindPassword)
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if err != nil {
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log.Debug("Failed to bind as BindDN[%s]: %v", ls.BindDN, err)
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return nil, err
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}
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log.Trace("Bound as BindDN %s", ls.BindDN)
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} else {
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log.Trace("Proceeding with anonymous LDAP search.")
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}
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userFilter := fmt.Sprintf(ls.Filter, "*")
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var isAttributeSSHPublicKeySet = len(strings.TrimSpace(ls.AttributeSSHPublicKey)) > 0
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attribs := []string{ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail}
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if isAttributeSSHPublicKeySet {
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attribs = append(attribs, ls.AttributeSSHPublicKey)
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}
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log.Trace("Fetching attributes '%v', '%v', '%v', '%v', '%v' with filter %s and base %s", ls.AttributeUsername, ls.AttributeName, ls.AttributeSurname, ls.AttributeMail, ls.AttributeSSHPublicKey, userFilter, ls.UserBase)
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search := ldap.NewSearchRequest(
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ls.UserBase, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, userFilter,
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attribs, nil)
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var sr *ldap.SearchResult
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if ls.UsePagedSearch() {
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sr, err = l.SearchWithPaging(search, ls.SearchPageSize)
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} else {
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sr, err = l.Search(search)
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}
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if err != nil {
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log.Error("LDAP Search failed unexpectedly! (%v)", err)
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return nil, err
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}
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result := make([]*SearchResult, len(sr.Entries))
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for i, v := range sr.Entries {
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result[i] = &SearchResult{
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Username: v.GetAttributeValue(ls.AttributeUsername),
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Name: v.GetAttributeValue(ls.AttributeName),
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Surname: v.GetAttributeValue(ls.AttributeSurname),
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Mail: v.GetAttributeValue(ls.AttributeMail),
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IsAdmin: checkAdmin(l, ls, v.DN),
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}
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if isAttributeSSHPublicKeySet {
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result[i].SSHPublicKey = v.GetAttributeValues(ls.AttributeSSHPublicKey)
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}
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}
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return result, nil
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}
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