authelia/internal/authentication/ldap_user_provider.go
2020-09-04 13:20:17 +10:00

297 lines
8.9 KiB
Go

package authentication
import (
"crypto/tls"
"fmt"
"net/url"
"strings"
"github.com/go-ldap/ldap/v3"
"github.com/authelia/authelia/internal/configuration/schema"
"github.com/authelia/authelia/internal/logging"
)
// LDAPUserProvider is a provider using a LDAP or AD as a user database.
type LDAPUserProvider struct {
configuration schema.LDAPAuthenticationBackendConfiguration
connectionFactory LDAPConnectionFactory
}
// NewLDAPUserProvider creates a new instance of LDAPUserProvider.
func NewLDAPUserProvider(configuration schema.LDAPAuthenticationBackendConfiguration) *LDAPUserProvider {
return &LDAPUserProvider{
configuration: configuration,
connectionFactory: NewLDAPConnectionFactoryImpl(),
}
}
// NewLDAPUserProviderWithFactory creates a new instance of LDAPUserProvider with existing factory.
func NewLDAPUserProviderWithFactory(configuration schema.LDAPAuthenticationBackendConfiguration,
connectionFactory LDAPConnectionFactory) *LDAPUserProvider {
return &LDAPUserProvider{
configuration: configuration,
connectionFactory: connectionFactory,
}
}
func (p *LDAPUserProvider) connect(userDN string, password string) (LDAPConnection, error) {
var newConnection LDAPConnection
url, err := url.Parse(p.configuration.URL)
if err != nil {
return nil, fmt.Errorf("Unable to parse URL to LDAP: %s", url)
}
if url.Scheme == "ldaps" {
logging.Logger().Trace("LDAP client starts a TLS session")
conn, err := p.connectionFactory.DialTLS("tcp", url.Host, &tls.Config{
InsecureSkipVerify: p.configuration.SkipVerify, //nolint:gosec // This is a configurable option, is desirable in some situations and is off by default.
})
if err != nil {
return nil, err
}
newConnection = conn
} else {
logging.Logger().Trace("LDAP client starts a session over raw TCP")
conn, err := p.connectionFactory.Dial("tcp", url.Host)
if err != nil {
return nil, err
}
newConnection = conn
}
if err := newConnection.Bind(userDN, password); err != nil {
return nil, err
}
return newConnection, nil
}
// CheckUserPassword checks if provided password matches for the given user.
func (p *LDAPUserProvider) CheckUserPassword(inputUsername string, password string) (bool, error) {
adminClient, err := p.connect(p.configuration.User, p.configuration.Password)
if err != nil {
return false, err
}
defer adminClient.Close()
profile, err := p.getUserProfile(adminClient, inputUsername)
if err != nil {
return false, err
}
conn, err := p.connect(profile.DN, password)
if err != nil {
return false, fmt.Errorf("Authentication of user %s failed. Cause: %s", inputUsername, err)
}
defer conn.Close()
return true, nil
}
// OWASP recommends to escape some special characters.
// https://github.com/OWASP/CheatSheetSeries/blob/master/cheatsheets/LDAP_Injection_Prevention_Cheat_Sheet.md
const specialLDAPRunes = ",#+<>;\"="
func (p *LDAPUserProvider) ldapEscape(inputUsername string) string {
inputUsername = ldap.EscapeFilter(inputUsername)
for _, c := range specialLDAPRunes {
inputUsername = strings.ReplaceAll(inputUsername, string(c), fmt.Sprintf("\\%c", c))
}
return inputUsername
}
type ldapUserProfile struct {
DN string
Emails []string
DisplayName string
Username string
}
func (p *LDAPUserProvider) resolveUsersFilter(userFilter string, inputUsername string) string {
inputUsername = p.ldapEscape(inputUsername)
// We temporarily keep placeholder {0} for backward compatibility.
userFilter = strings.ReplaceAll(userFilter, "{0}", inputUsername)
// The {username} placeholder is equivalent to {0}, it's the new way, a named placeholder.
userFilter = strings.ReplaceAll(userFilter, "{input}", inputUsername)
// {username_attribute} and {mail_attribute} are replaced by the content of the attribute defined
// in configuration.
userFilter = strings.ReplaceAll(userFilter, "{username_attribute}", p.configuration.UsernameAttribute)
userFilter = strings.ReplaceAll(userFilter, "{mail_attribute}", p.configuration.MailAttribute)
userFilter = strings.ReplaceAll(userFilter, "{display_name_attribute}", p.configuration.DisplayNameAttribute)
return userFilter
}
func (p *LDAPUserProvider) getUserProfile(conn LDAPConnection, inputUsername string) (*ldapUserProfile, error) {
userFilter := p.resolveUsersFilter(p.configuration.UsersFilter, inputUsername)
logging.Logger().Tracef("Computed user filter is %s", userFilter)
baseDN := p.configuration.BaseDN
if p.configuration.AdditionalUsersDN != "" {
baseDN = p.configuration.AdditionalUsersDN + "," + baseDN
}
attributes := []string{"dn",
p.configuration.DisplayNameAttribute,
p.configuration.MailAttribute,
p.configuration.UsernameAttribute}
// Search for the given username.
searchRequest := ldap.NewSearchRequest(
baseDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases,
1, 0, false, userFilter, attributes, nil,
)
sr, err := conn.Search(searchRequest)
if err != nil {
return nil, fmt.Errorf("Cannot find user DN of user %s. Cause: %s", inputUsername, err)
}
if len(sr.Entries) == 0 {
return nil, ErrUserNotFound
}
if len(sr.Entries) > 1 {
return nil, fmt.Errorf("Multiple users %s found", inputUsername)
}
userProfile := ldapUserProfile{
DN: sr.Entries[0].DN,
}
for _, attr := range sr.Entries[0].Attributes {
if attr.Name == p.configuration.DisplayNameAttribute {
userProfile.DisplayName = attr.Values[0]
}
if attr.Name == p.configuration.MailAttribute {
userProfile.Emails = attr.Values
}
if attr.Name == p.configuration.UsernameAttribute {
if len(attr.Values) != 1 {
return nil, fmt.Errorf("User %s cannot have multiple value for attribute %s",
inputUsername, p.configuration.UsernameAttribute)
}
userProfile.Username = attr.Values[0]
}
}
if userProfile.DN == "" {
return nil, fmt.Errorf("No DN has been found for user %s", inputUsername)
}
return &userProfile, nil
}
func (p *LDAPUserProvider) resolveGroupsFilter(inputUsername string, profile *ldapUserProfile) (string, error) { //nolint:unparam
inputUsername = p.ldapEscape(inputUsername)
// We temporarily keep placeholder {0} for backward compatibility.
groupFilter := strings.ReplaceAll(p.configuration.GroupsFilter, "{0}", inputUsername)
groupFilter = strings.ReplaceAll(groupFilter, "{input}", inputUsername)
if profile != nil {
// We temporarily keep placeholder {1} for backward compatibility.
groupFilter = strings.ReplaceAll(groupFilter, "{1}", ldap.EscapeFilter(profile.Username))
groupFilter = strings.ReplaceAll(groupFilter, "{username}", ldap.EscapeFilter(profile.Username))
groupFilter = strings.ReplaceAll(groupFilter, "{dn}", ldap.EscapeFilter(profile.DN))
}
return groupFilter, nil
}
// GetDetails retrieve the groups a user belongs to.
func (p *LDAPUserProvider) GetDetails(inputUsername string) (*UserDetails, error) {
conn, err := p.connect(p.configuration.User, p.configuration.Password)
if err != nil {
return nil, err
}
defer conn.Close()
profile, err := p.getUserProfile(conn, inputUsername)
if err != nil {
return nil, err
}
groupsFilter, err := p.resolveGroupsFilter(inputUsername, profile)
if err != nil {
return nil, fmt.Errorf("Unable to create group filter for user %s. Cause: %s", inputUsername, err)
}
logging.Logger().Tracef("Computed groups filter is %s", groupsFilter)
groupBaseDN := p.configuration.BaseDN
if p.configuration.AdditionalGroupsDN != "" {
groupBaseDN = p.configuration.AdditionalGroupsDN + "," + groupBaseDN
}
// Search for the given username.
searchGroupRequest := ldap.NewSearchRequest(
groupBaseDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases,
0, 0, false, groupsFilter, []string{p.configuration.GroupNameAttribute}, nil,
)
sr, err := conn.Search(searchGroupRequest)
if err != nil {
return nil, fmt.Errorf("Unable to retrieve groups of user %s. Cause: %s", inputUsername, err)
}
groups := make([]string, 0)
for _, res := range sr.Entries {
if len(res.Attributes) == 0 {
logging.Logger().Warningf("No groups retrieved from LDAP for user %s", inputUsername)
break
}
// Append all values of the document. Normally there should be only one per document.
groups = append(groups, res.Attributes[0].Values...)
}
return &UserDetails{
Username: profile.Username,
DisplayName: profile.DisplayName,
Emails: profile.Emails,
Groups: groups,
}, nil
}
// UpdatePassword update the password of the given user.
func (p *LDAPUserProvider) UpdatePassword(inputUsername string, newPassword string) error {
client, err := p.connect(p.configuration.User, p.configuration.Password)
if err != nil {
return fmt.Errorf("Unable to update password. Cause: %s", err)
}
profile, err := p.getUserProfile(client, inputUsername)
if err != nil {
return fmt.Errorf("Unable to update password. Cause: %s", err)
}
modifyRequest := ldap.NewModifyRequest(profile.DN, nil)
modifyRequest.Replace("userPassword", []string{newPassword})
err = client.Modify(modifyRequest)
if err != nil {
return fmt.Errorf("Unable to update password. Cause: %s", err)
}
return nil
}