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ldap.go
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ldap.go
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/*
* Copyright 2017-2019 Kopano and its licensors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package backends
import (
"context"
"crypto/tls"
"encoding/base64"
"fmt"
"net"
"net/url"
"strconv"
"strings"
"time"
"github.com/go-ldap/ldap/v3"
"github.com/satori/go.uuid"
"github.com/sirupsen/logrus"
"golang.org/x/time/rate"
"stash.kopano.io/kgol/oidc-go"
"stash.kopano.io/kc/konnect"
"stash.kopano.io/kc/konnect/config"
ldapDefinitions "stash.kopano.io/kc/konnect/identifier/backends/ldap"
"stash.kopano.io/kc/konnect/identifier/meta/scopes"
)
const ldapIdentifierBackendName = "identifier-ldap"
var ldapSupportedScopes = []string{
oidc.ScopeProfile,
oidc.ScopeEmail,
konnect.ScopeUniqueUserID,
konnect.ScopeRawSubject,
}
// LDAPIdentifierBackend is a backend for the Identifier which connects LDAP.
type LDAPIdentifierBackend struct {
addr string
isTLS bool
bindDN string
bindPassword string
baseDN string
scope int
searchFilter string
getFilter string
entryIDMapping []string
attributeMapping ldapAttributeMapping
supportedScopes []string
logger logrus.FieldLogger
dialer *net.Dialer
tlsConfig *tls.Config
timeout int
limiter *rate.Limiter
}
type ldapAttributeMapping map[string]string
var ldapDefaultAttributeMapping = ldapAttributeMapping{
ldapDefinitions.AttributeLogin: ldapDefinitions.AttributeLogin,
ldapDefinitions.AttributeEmail: ldapDefinitions.AttributeEmail,
ldapDefinitions.AttributeName: ldapDefinitions.AttributeName,
ldapDefinitions.AttributeFamilyName: ldapDefinitions.AttributeFamilyName,
ldapDefinitions.AttributeGivenName: ldapDefinitions.AttributeGivenName,
ldapDefinitions.AttributeUUID: ldapDefinitions.AttributeUUID,
fmt.Sprintf("%s_type", ldapDefinitions.AttributeUUID): ldapDefinitions.AttributeValueTypeText,
}
func (m ldapAttributeMapping) attributes() []string {
attributes := make([]string, len(m)+1)
attributes[0] = ldapDefinitions.AttributeDN
idx := 1
for _, attribute := range m {
attributes[idx] = attribute
idx++
}
return attributes
}
type ldapUser struct {
entryID string
id int64
data ldapAttributeMapping
}
func newLdapUser(entryID string, mapping ldapAttributeMapping, entry *ldap.Entry) (*ldapUser, error) {
// Go through all returned attributes, add them to the local data set if
// we know them in the mapping.
var id int64
data := make(ldapAttributeMapping)
for _, attribute := range entry.Attributes {
if len(attribute.Values) == 0 {
continue
}
for n, mapped := range mapping {
// LDAP attribute descriptors / short names are case insensitive. See
// https://tools.ietf.org/html/rfc4512#page-4.
if strings.ToLower(attribute.Name) == strings.ToLower(mapped) {
// Check if we need conversion.
switch mapping[fmt.Sprintf("%s_type", n)] {
case ldapDefinitions.AttributeValueTypeBinary:
// Binary gets encoded witih Base64.
data[n] = base64.StdEncoding.EncodeToString(attribute.ByteValues[0])
case ldapDefinitions.AttributeValueTypeUUID:
// Try to decode as UUID https://tools.ietf.org/html/rfc4122 and
// serialize to string.
if value, err := uuid.FromBytes(attribute.ByteValues[0]); err == nil {
data[n] = value.String()
}
default:
data[n] = attribute.Values[0]
}
if n == ldapDefinitions.AttributeNumericUID {
numericID, err := strconv.ParseInt(data[n], 10, 64)
if err != nil {
return nil, fmt.Errorf("invalid numeric ID %v in record", err)
}
id = numericID
}
}
}
}
return &ldapUser{
entryID: entryID,
id: id,
data: data,
}, nil
}
func (u *ldapUser) getAttributeValue(n string) string {
if n == "" {
return ""
}
return u.data[n]
}
func (u *ldapUser) Subject() string {
return u.entryID
}
func (u *ldapUser) Email() string {
return u.getAttributeValue(ldapDefinitions.AttributeEmail)
}
func (u *ldapUser) EmailVerified() bool {
return false
}
func (u *ldapUser) Name() string {
return u.getAttributeValue(ldapDefinitions.AttributeName)
}
func (u *ldapUser) FamilyName() string {
return u.getAttributeValue(ldapDefinitions.AttributeFamilyName)
}
func (u *ldapUser) GivenName() string {
return u.getAttributeValue(ldapDefinitions.AttributeGivenName)
}
func (u *ldapUser) Username() string {
return u.getAttributeValue(ldapDefinitions.AttributeLogin)
}
func (u *ldapUser) ID() int64 {
return u.id
}
func (u *ldapUser) UniqueID() string {
return u.getAttributeValue(ldapDefinitions.AttributeUUID)
}
func (u *ldapUser) BackendClaims() map[string]interface{} {
claims := make(map[string]interface{})
claims[konnect.IdentifiedUserIDClaim] = u.entryID
return claims
}
// NewLDAPIdentifierBackend creates a new LDAPIdentifierBackend with the provided
// parameters.
func NewLDAPIdentifierBackend(
c *config.Config,
tlsConfig *tls.Config,
uriString,
bindDN,
bindPassword,
baseDN,
scopeString,
filter string,
subAttributes []string,
mappedAttributes map[string]string,
) (*LDAPIdentifierBackend, error) {
var err error
var scope int
var uri *url.URL
for {
if uriString == "" {
err = fmt.Errorf("server must not be empty")
break
}
uri, err = url.Parse(uriString)
if err != nil {
break
}
if bindDN == "" && bindPassword != "" {
err = fmt.Errorf("bind DN must not be empty when bind password is given")
break
}
if baseDN == "" {
err = fmt.Errorf("base DN must not be empty")
break
}
switch scopeString {
case "sub":
scope = ldap.ScopeWholeSubtree
case "one":
scope = ldap.ScopeSingleLevel
case "base":
scope = ldap.ScopeBaseObject
case "":
scope = ldap.ScopeWholeSubtree
default:
err = fmt.Errorf("unknown scope value: %v, must be one of sub, one or base", scopeString)
}
if err != nil {
break
}
break
}
if err != nil {
return nil, fmt.Errorf("ldap identifier backend %v", err)
}
attributeMapping := ldapAttributeMapping{}
for k, v := range ldapDefaultAttributeMapping {
if mapped, ok := mappedAttributes[k]; ok && mapped != "" {
v = mapped
}
attributeMapping[k] = v
c.Logger.WithField("attribute", fmt.Sprintf("%v:%v", k, v)).Debugln("ldap identifier backend set attribute")
}
// Build supported scopes based on default scopes and scope mapping.
supportedScopes := make([]string, len(ldapSupportedScopes))
copy(supportedScopes, ldapSupportedScopes)
if numericUIDAttribute := mappedAttributes[ldapDefinitions.AttributeNumericUID]; numericUIDAttribute != "" {
supportedScopes = append(supportedScopes, konnect.ScopeID)
attributeMapping[ldapDefinitions.AttributeNumericUID] = numericUIDAttribute
c.Logger.WithField("attribute", fmt.Sprintf("%v:%v", ldapDefinitions.AttributeNumericUID, numericUIDAttribute)).Debugln("ldap identifier backend use attribute")
}
if filter == "" {
filter = "(objectClass=inetOrgPerson)"
}
c.Logger.WithField("filter", filter).Debugln("ldap identifier backend set filter")
loginAttribute := attributeMapping[ldapDefinitions.AttributeLogin]
addr := uri.Host
isTLS := false
switch uri.Scheme {
case "":
uri.Scheme = "ldap"
fallthrough
case "ldap":
if uri.Port() == "" {
addr += ":389"
}
case "ldaps":
if uri.Port() == "" {
addr += ":636"
}
isTLS = true
default:
err = fmt.Errorf("invalid URI scheme: %v", uri.Scheme)
}
if err != nil {
return nil, fmt.Errorf("ldap identifier backend %v", err)
}
var entryIDMapping []string
if len(subAttributes) > 0 {
entryIDMapping = subAttributes
c.Logger.WithField("mapping", entryIDMapping).Debugln("ldap identifier sub is mapped")
}
b := &LDAPIdentifierBackend{
addr: addr,
isTLS: isTLS,
bindDN: bindDN,
bindPassword: bindPassword,
baseDN: baseDN,
scope: scope,
searchFilter: fmt.Sprintf("(&(%s)(%s=%%s))", filter, loginAttribute),
getFilter: filter,
entryIDMapping: entryIDMapping,
attributeMapping: attributeMapping,
supportedScopes: supportedScopes,
logger: c.Logger,
dialer: &net.Dialer{
Timeout: ldap.DefaultTimeout,
DualStack: true,
},
tlsConfig: tlsConfig,
timeout: 60, //XXX(longsleep): make timeout configuration.
limiter: rate.NewLimiter(100, 200), //XXX(longsleep): make rate limits configuration.
}
b.logger.WithField("ldap", fmt.Sprintf("%s://%s ", uri.Scheme, addr)).Infoln("ldap server identifier backend set up")
return b, nil
}
// RunWithContext implements the Backend interface.
func (b *LDAPIdentifierBackend) RunWithContext(ctx context.Context) error {
return nil
}
// Logon implements the Backend interface, enabling Logon with user name and
// password as provided. Requests are bound to the provided context.
func (b *LDAPIdentifierBackend) Logon(ctx context.Context, audience, username, password string) (bool, *string, *string, map[string]interface{}, error) {
loginAttributeName := b.attributeMapping[ldapDefinitions.AttributeLogin]
if loginAttributeName == "" {
return false, nil, nil, nil, fmt.Errorf("ldap identifier backend logon impossible as no login attribute is set")
}
l, err := b.connect(ctx)
if err != nil {
return false, nil, nil, nil, fmt.Errorf("ldap identifier backend logon connect error: %v", err)
}
defer l.Close()
// Search for the given username.
entry, err := b.searchUsername(l, username, b.attributeMapping.attributes())
switch {
case ldap.IsErrorWithCode(err, ldap.LDAPResultNoSuchObject):
return false, nil, nil, nil, nil
}
if err != nil {
return false, nil, nil, nil, fmt.Errorf("ldap identifier backend logon search error: %v", err)
}
if !strings.EqualFold(entry.GetAttributeValue(loginAttributeName), username) {
return false, nil, nil, nil, fmt.Errorf("ldap identifier backend logon search returned wrong user")
}
// Bind as the user to verify the password.
err = l.Bind(entry.DN, password)
switch {
case ldap.IsErrorWithCode(err, ldap.LDAPResultInvalidCredentials):
return false, nil, nil, nil, nil
}
if err != nil {
return false, nil, nil, nil, fmt.Errorf("ldap identifier backend logon error: %v", err)
}
entryID := b.entryIDFromEntry(b.attributeMapping, entry)
if entryID == "" {
return false, nil, nil, nil, fmt.Errorf("ldap identifier backend logon entry without entry ID: %v", entry.DN)
}
user, err := newLdapUser(entryID, b.attributeMapping, entry)
if err != nil {
return false, nil, nil, nil, fmt.Errorf("ldap identifier backend logon entry data error: %v", err)
}
b.logger.WithFields(logrus.Fields{
"username": username,
"id": entryID,
}).Debugln("ldap identifier backend logon")
return true, &entryID, nil, user.BackendClaims(), nil
}
// ResolveUserByUsername implements the Beckend interface, providing lookup for
// user by providing the username. Requests are bound to the provided context.
func (b *LDAPIdentifierBackend) ResolveUserByUsername(ctx context.Context, username string) (UserFromBackend, error) {
loginAttributeName := b.attributeMapping[ldapDefinitions.AttributeLogin]
if loginAttributeName == "" {
return nil, fmt.Errorf("ldap identifier backend resolve impossible as no login attribute is set")
}
l, err := b.connect(ctx)
if err != nil {
return nil, fmt.Errorf("ldap identifier backend resolve connect error: %v", err)
}
defer l.Close()
// Search for the given username.
entry, err := b.searchUsername(l, username, b.attributeMapping.attributes())
switch {
case ldap.IsErrorWithCode(err, ldap.LDAPResultNoSuchObject):
return nil, nil
}
if err != nil {
return nil, fmt.Errorf("ldap identifier backend resolve search error: %v", err)
}
if !strings.EqualFold(entry.GetAttributeValue(loginAttributeName), username) {
return nil, fmt.Errorf("ldap identifier backend resolve search returned wrong user")
}
newEntryID := b.entryIDFromEntry(b.attributeMapping, entry)
user, err := newLdapUser(newEntryID, b.attributeMapping, entry)
if err != nil {
return nil, fmt.Errorf("ldap identifier backend resolve entry data error: %v", err)
}
return user, nil
}
// GetUser implements the Backend interface, providing user meta data retrieval
// for the user specified by the userID. Requests are bound to the provided
// context.
func (b *LDAPIdentifierBackend) GetUser(ctx context.Context, entryID string, sessionRef *string) (UserFromBackend, error) {
l, err := b.connect(ctx)
if err != nil {
return nil, fmt.Errorf("ldap identifier backend get user connect error: %v", err)
}
defer l.Close()
entry, err := b.getUser(l, entryID, b.attributeMapping.attributes())
if err != nil {
return nil, fmt.Errorf("ldap identifier backend get user error: %v", err)
}
newEntryID := b.entryIDFromEntry(b.attributeMapping, entry)
if !strings.EqualFold(newEntryID, entryID) {
return nil, fmt.Errorf("ldap identifier backend get user returned wrong user")
}
user, err := newLdapUser(newEntryID, b.attributeMapping, entry)
if err != nil {
return nil, fmt.Errorf("ldap identifier backend get user entry data error: %v", err)
}
return user, err
}
// RefreshSession implements the Backend interface.
func (b *LDAPIdentifierBackend) RefreshSession(ctx context.Context, userID string, sessionRef *string, claims map[string]interface{}) error {
return nil
}
// DestroySession implements the Backend interface providing destroy to KC session.
func (b *LDAPIdentifierBackend) DestroySession(ctx context.Context, sessionRef *string) error {
return nil
}
// UserClaims implements the Backend interface, providing user specific claims
// for the user specified by the userID.
func (b *LDAPIdentifierBackend) UserClaims(userID string, authorizedScopes map[string]bool) map[string]interface{} {
return nil
}
// ScopesSupported implements the Backend interface, providing supported scopes
// when running this backend.
func (b *LDAPIdentifierBackend) ScopesSupported() []string {
return b.supportedScopes
}
// ScopesMeta implements the Backend interface, providing meta data for
// supported scopes.
func (b *LDAPIdentifierBackend) ScopesMeta() *scopes.Scopes {
return nil
}
// Name implements the Backend interface.
func (b *LDAPIdentifierBackend) Name() string {
return ldapIdentifierBackendName
}
func (b *LDAPIdentifierBackend) connect(parentCtx context.Context) (*ldap.Conn, error) {
// A timeout for waiting for a limiter slot. The timeout also includes the
// time to connect to the LDAP server which as a consequence means that both
// getting a free slot and establishing the connection are one timeout.
ctx, cancel := context.WithTimeout(parentCtx, time.Duration(b.timeout)*time.Second)
defer cancel()
err := b.limiter.Wait(ctx)
if err != nil {
return nil, err
}
c, err := b.dialer.DialContext(ctx, "tcp", b.addr)
if err != nil {
return nil, ldap.NewError(ldap.ErrorNetwork, err)
}
var l *ldap.Conn
if b.isTLS {
sc := tls.Client(c, b.tlsConfig)
err = sc.Handshake()
if err != nil {
c.Close()
return nil, ldap.NewError(ldap.ErrorNetwork, err)
}
l = ldap.NewConn(sc, true)
} else {
l = ldap.NewConn(c, false)
}
l.Start()
// Bind with general user (which is preferably read only).
if b.bindDN != "" {
err = l.Bind(b.bindDN, b.bindPassword)
if err != nil {
return nil, err
}
}
return l, nil
}
func (b *LDAPIdentifierBackend) searchUsername(l *ldap.Conn, username string, attributes []string) (*ldap.Entry, error) {
base, filter := b.baseAndSearchFilterFromUsername(username)
// Search for the given username.
searchRequest := ldap.NewSearchRequest(
base,
b.scope, ldap.NeverDerefAliases, 1, b.timeout, false,
filter,
attributes,
nil,
)
sr, err := l.Search(searchRequest)
if err != nil {
return nil, err
}
switch len(sr.Entries) {
case 0:
// Nothing found.
return nil, ldap.NewError(ldap.LDAPResultNoSuchObject, err)
case 1:
// Exactly one found, success.
return sr.Entries[0], nil
default:
// Invalid when multiple matched.
return nil, fmt.Errorf("user too many entries returned")
}
}
func (b *LDAPIdentifierBackend) getUser(l *ldap.Conn, entryID string, attributes []string) (*ldap.Entry, error) {
base, filter := b.baseAndGetFilterFromEntryID(entryID)
if base == "" || filter == "" || entryID == "" {
return nil, fmt.Errorf("ldap identifier backend get user invalid user ID: %v", entryID)
}
scope := b.scope
if base == entryID {
// Ensure that scope is limited, when directly requesting an entry.
scope = ldap.ScopeBaseObject
}
// search for the given DN.
searchRequest := ldap.NewSearchRequest(
base,
scope, ldap.NeverDerefAliases, 1, b.timeout, false,
filter,
attributes,
nil,
)
sr, err := l.Search(searchRequest)
if err != nil {
return nil, err
}
if len(sr.Entries) != 1 {
return nil, fmt.Errorf("user does not exist or too many entries returned")
}
return sr.Entries[0], nil
}
func (b *LDAPIdentifierBackend) entryIDFromEntry(mapping ldapAttributeMapping, entry *ldap.Entry) string {
if b.entryIDMapping != nil {
// Encode as URL query.
values := url.Values{}
for _, k := range b.entryIDMapping {
v := entry.GetAttributeValues(k)
if len(v) > 0 {
values[k] = v
}
}
// URL encode values to string.
return values.Encode()
}
// Use DN by default is no mapping is set.
return entry.DN
}
func (b *LDAPIdentifierBackend) baseAndGetFilterFromEntryID(entryID string) (string, string) {
if b.entryIDMapping != nil {
// Parse entryID as URL encoded query values, and build & filter to search for them all.
if values, err := url.ParseQuery(entryID); err == nil {
filter := ""
for k, values := range values {
for _, value := range values {
filter = fmt.Sprintf("%s(%s=%s)", filter, k, value)
}
}
if filter != "" {
return b.baseDN, fmt.Sprintf("(&%s%s)", b.getFilter, filter)
}
}
// Failed to parse entry ID.
return "", ""
}
// Map DN to entryID.
_, err := ldap.ParseDN(entryID)
if err != nil {
return "", ""
}
return entryID, b.getFilter
}
func (b *LDAPIdentifierBackend) baseAndSearchFilterFromUsername(username string) (string, string) {
// Build search filter with username.
return b.baseDN, fmt.Sprintf(b.searchFilter, username)
}