gitea/modules/auth/ldap/ldap.go
Adam Strzelecki 834d92a47b LDAP: Fetch attributes in Bind DN context option
This is feature is workaround for #2628 (JumpCloud) and some other services
that allow LDAP search only under BindDN user account, but not allow any LDAP
search query in logged user DN context.

Such approach is an alternative to minimal permissions security pattern for
BindDN user.
2016-02-20 14:12:32 +01:00

220 lines
6.5 KiB
Go

// 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"
)
// Basic LDAP authentication service
type Source struct {
Name string // canonical name (ie. corporate.ad)
Host string // LDAP host
Port int // port number
UseSSL bool // Use SSL
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 using filter %s", userFilter)
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
}
// 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 := ldapDial(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
}
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_attr := sr.Entries[0].GetAttributeValue(ls.AttributeUsername)
name_attr := sr.Entries[0].GetAttributeValue(ls.AttributeName)
sn_attr := sr.Entries[0].GetAttributeValue(ls.AttributeSurname)
mail_attr := sr.Entries[0].GetAttributeValue(ls.AttributeMail)
admin_attr := false
if len(ls.AdminFilter) > 0 {
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 {
admin_attr = 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_attr, name_attr, sn_attr, mail_attr, admin_attr, true
}
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
}
func ldapDial(ls *Source) (*ldap.Conn, error) {
if ls.UseSSL {
log.Debug("Using TLS for LDAP without verifying: %v", ls.SkipVerify)
return ldap.DialTLS("tcp", fmt.Sprintf("%s:%d", ls.Host, ls.Port), &tls.Config{
InsecureSkipVerify: ls.SkipVerify,
})
} else {
return ldap.Dial("tcp", fmt.Sprintf("%s:%d", ls.Host, ls.Port))
}
}