A cloud-native LDAP server backed by a Consul datastore
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 

553 lines
15 KiB

package main
import (
"encoding/json"
"fmt"
"strings"
ldap "bottin/ldapserver"
consul "github.com/hashicorp/consul/api"
message "github.com/lor00x/goldap/message"
)
// Generic item modification function --------
func (server *Server) putAttributes(dn string, attrs Entry) error {
prefix, err := dnToConsul(dn)
if err != nil {
return err
}
// Normalize attribute names: if we have several times the same attr
// but with different cases, put that in the same attr
normalized := make(Entry)
for k, values := range attrs {
found := false
for k2 := range normalized {
if strings.EqualFold(k, k2) {
normalized[k2] = append(normalized[k2], values...)
found = true
break
}
}
if !found {
normalized[k] = values
}
}
// Retreieve previously existing attributes, which we will use to delete
// entries with the wrong case
previous_pairs, _, err := server.kv.List(prefix + "/attribute=", &server.readOpts)
if err != nil {
return err
}
for k, valuesNC := range normalized {
path := prefix + "/attribute=" + k
// Trim spaces and remove empty values
values := []string{}
for _, v := range valuesNC {
vv := strings.TrimSpace(v)
if len(vv) > 0 {
values = append(values, vv)
}
}
// If previously existing pairs with the wrong case exist, delete them
for _, prev_pair := range previous_pairs {
if strings.EqualFold(prev_pair.Key, path) && prev_pair.Key != path {
_, err := server.kv.Delete(prev_pair.Key, nil)
if err != nil {
return err
}
}
}
// If we have zero values, delete associated k/v pair
// Otherwise, write new values
if len(values) == 0 {
_, err := server.kv.Delete(path, nil)
if err != nil {
return err
}
} else {
json, err := json.MarshalIndent(values, "", " ")
if err != nil {
return err
}
pair := &consul.KVPair{Key: path, Value: json}
_, err = server.kv.Put(pair, nil)
if err != nil {
return err
}
}
}
return nil
}
// Add request ------------------------
func (server *Server) handleAdd(s ldap.UserState, w ldap.ResponseWriter, m *ldap.Message) {
state := s.(*State)
r := m.GetAddRequest()
code, err := server.handleAddInternal(state, &r)
res := ldap.NewResponse(code)
if err != nil {
res.SetDiagnosticMessage(err.Error())
}
if code == ldap.LDAPResultSuccess {
server.logger.Printf("Successfully added %s", string(r.Entry()))
} else {
server.logger.Printf("Failed to add %s (%s)", string(r.Entry()), err)
}
w.Write(message.AddResponse(res))
}
func (server *Server) handleAddInternal(state *State, r *message.AddRequest) (int, error) {
dn, err := server.checkDN(string(r.Entry()), false)
if err != nil {
return ldap.LDAPResultInvalidDNSyntax, err
}
dnSplit, err := parseDN(dn)
if err != nil {
return ldap.LDAPResultInvalidDNSyntax, err
}
// Check permissions
attrListStr := []string{}
for _, attribute := range r.Attributes() {
attrListStr = append(attrListStr, string(attribute.Type_()))
}
if !server.config.Acl.Check(&state.login, "add", dn, attrListStr) {
return ldap.LDAPResultInsufficientAccessRights, nil
}
// Check that object does not already exist
exists, err := server.objectExists(dn)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
if exists {
return ldap.LDAPResultEntryAlreadyExists, nil
}
// Check that parent object exists
parentDn := unparseDN(dnSplit[1:])
parentExists, err := server.objectExists(parentDn)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
if !parentExists {
return ldap.LDAPResultNoSuchObject, fmt.Errorf(
"Parent object %s does not exist", parentDn)
}
// If adding a group, track of who the members will be so that their memberOf field can be updated later
members := []string{}
// Check attributes
entry := Entry{}
for _, attribute := range r.Attributes() {
key := string(attribute.Type_())
vals_str := []string{}
for _, val := range attribute.Vals() {
vals_str = append(vals_str, string(val))
}
// Fail if they are trying to write memberOf, we manage this ourselves
err = checkRestrictedAttr(key)
if err != nil {
return ldap.LDAPResultObjectClassViolation, err
}
if strings.EqualFold(key, ATTR_MEMBER) {
// If they are writing a member list, we have to check they are adding valid members
// Also, rewrite member list to use canonical DN syntax (no spaces, all lowercase)
for _, member := range vals_str {
member_canonical, err := server.checkDN(member, false)
if err != nil {
return ldap.LDAPResultInvalidDNSyntax, err
}
exists, err = server.objectExists(member_canonical)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
if !exists {
return ldap.LDAPResultNoSuchObject, fmt.Errorf(
"Cannot add %s to members, it does not exist!",
member_canonical)
}
members = append(members, member_canonical)
}
entry[key] = members
} else {
if prev, ok := entry[key]; ok {
entry[key] = append(prev, vals_str...)
} else {
entry[key] = vals_str
}
}
}
// Ensure object has at least one objectclass value
hasObjectClass := false
for k := range entry {
if strings.EqualFold(k, ATTR_OBJECTCLASS) {
hasObjectClass = true
break
}
}
if !hasObjectClass {
entry[ATTR_OBJECTCLASS] = []string{"top"}
}
// Write system attributes
entry[ATTR_CREATORSNAME] = []string{state.login.user}
entry[ATTR_CREATETIMESTAMP] = []string{genTimestamp()}
entry[ATTR_ENTRYUUID] = []string{genUuid()}
entry[dnSplit[0].Type] = []string{dnSplit[0].Value}
// Add our item in the DB
err = server.putAttributes(dn, entry)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
// ~~ from this point on, our operation succeeded ~~
// ~~ future errors cause inconsistencies in the DB and are logged ~~
// If our item has a member list, add it to all of its member's memberOf attribute
for _, member := range members {
server.memberOfAdd(member, dn)
}
return ldap.LDAPResultSuccess, nil
}
// Delete request ------------------------
func (server *Server) handleDelete(s ldap.UserState, w ldap.ResponseWriter, m *ldap.Message) {
state := s.(*State)
r := m.GetDeleteRequest()
code, err := server.handleDeleteInternal(state, &r)
res := ldap.NewResponse(code)
if err != nil {
res.SetDiagnosticMessage(err.Error())
}
if code == ldap.LDAPResultSuccess {
server.logger.Printf("Successfully deleted %s", string(r))
} else {
server.logger.Printf("Failed to delete %s (%s)", string(r), err)
}
w.Write(message.DelResponse(res))
}
func (server *Server) handleDeleteInternal(state *State, r *message.DelRequest) (int, error) {
dn, err := server.checkDN(string(*r), false)
if err != nil {
return ldap.LDAPResultInvalidDNSyntax, err
}
// Check for delete permission
if !server.config.Acl.Check(&state.login, "delete", dn, []string{}) {
return ldap.LDAPResultInsufficientAccessRights, nil
}
// Check that this LDAP entry exists and has no children
path, err := dnToConsul(dn)
if err != nil {
return ldap.LDAPResultInvalidDNSyntax, err
}
items, _, err := server.kv.List(path+"/", &server.readOpts)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
if len(items) == 0 {
return ldap.LDAPResultNoSuchObject, fmt.Errorf("Not found: %s", dn)
}
for _, item := range items {
itemDN, _, err := consulToDN(item.Key)
if err != nil {
continue
}
if itemDN != dn {
return ldap.LDAPResultNotAllowedOnNonLeaf, fmt.Errorf(
"Cannot delete %s as it has children", dn)
}
}
// Retrieve group membership before we delete everything
memberOf, err := server.getAttribute(dn, ATTR_MEMBEROF)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
memberList, err := server.getAttribute(dn, ATTR_MEMBER)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
// Delete the LDAP entry
_, err = server.kv.DeleteTree(path+"/", nil)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
// ~~ from this point on, our operation succeeded ~~
// ~~ future errors cause inconsistencies in the DB and are logged ~~
// Delete it from the member list of all the groups it was a member of
if memberOf != nil {
for _, group := range memberOf {
groupMembers, err := server.getAttribute(group, ATTR_MEMBER)
if err != nil {
server.logger.Warnf("Could not remove %s from members of %s: %s", dn, group, err)
continue
}
newMembers := []string{}
for _, memb := range groupMembers {
if memb != dn {
newMembers = append(newMembers, memb)
}
}
err = server.putAttributes(group, Entry{
ATTR_MEMBER: newMembers,
})
if err != nil {
server.logger.Warnf("Could not remove %s from members of %s: %s", dn, group, err)
}
}
}
// Delete it from all of its member's memberOf info
for _, member := range memberList {
server.memberOfRemove(member, dn)
}
return ldap.LDAPResultSuccess, nil
}
// Modify request ------------------------
func (server *Server) handleModify(s ldap.UserState, w ldap.ResponseWriter, m *ldap.Message) {
state := s.(*State)
r := m.GetModifyRequest()
code, err := server.handleModifyInternal(state, &r)
res := ldap.NewResponse(code)
if err != nil {
res.SetDiagnosticMessage(err.Error())
}
if code == ldap.LDAPResultSuccess {
server.logger.Printf("Successfully modified %s", string(r.Object()))
} else {
server.logger.Printf("Failed to modifiy %s (%s)", string(r.Object()), err)
}
w.Write(message.ModifyResponse(res))
}
func (server *Server) handleModifyInternal(state *State, r *message.ModifyRequest) (int, error) {
dn, err := server.checkDN(string(r.Object()), false)
if err != nil {
return ldap.LDAPResultInvalidDNSyntax, err
}
dnSplit, err := parseDN(dn)
if err != nil {
return ldap.LDAPResultInvalidDNSyntax, err
}
// First permission check with no particular attributes
if !server.config.Acl.Check(&state.login, "modify", dn, []string{}) &&
!server.config.Acl.Check(&state.login, "modifyAdd", dn, []string{}) {
return ldap.LDAPResultInsufficientAccessRights, nil
}
// Retrieve previous values (by the way, check object exists)
path, err := dnToConsul(dn)
if err != nil {
return ldap.LDAPResultInvalidDNSyntax, err
}
items, _, err := server.kv.List(path+"/attribute=", &server.readOpts)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
if len(items) == 0 {
return ldap.LDAPResultNoSuchObject, fmt.Errorf("Not found: %s", dn)
}
prevEntry := Entry{}
for _, item := range items {
itemDN, attr, err := consulToDN(item.Key)
if err != nil {
continue
}
if itemDN != dn {
server.logger.Fatal("itemDN != dn in handleModifyInternal")
}
vals, err := parseValue(item.Value)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
prevEntry[attr] = vals
}
// Keep track of group members added/deleted
addMembers, delMembers := []string{}, []string{}
// Produce new entry values to be saved
entry := Entry{}
for _, change := range r.Changes() {
attr := string(change.Modification().Type_())
changeValues := []string{}
for _, v := range change.Modification().Vals() {
changeValues = append(changeValues, string(v))
}
// If we already had an attribute with this name before,
// make sure we are using the same lowercase/uppercase
for prevAttr := range prevEntry {
if strings.EqualFold(attr, prevAttr) {
attr = prevAttr
break
}
}
// Check that this attribute is not system-managed thus restricted
err = checkRestrictedAttr(attr)
if err != nil {
return ldap.LDAPResultObjectClassViolation, err
}
if strings.EqualFold(attr, dnSplit[0].Type) {
return ldap.LDAPResultObjectClassViolation, fmt.Errorf("%s may not be changed as it is part of object path", attr)
}
// Check for permission to modify this attribute
if !(server.config.Acl.Check(&state.login, "modify", dn, []string{attr}) ||
(change.Operation() == ldap.ModifyRequestChangeOperationAdd &&
server.config.Acl.Check(&state.login, "modifyAdd", dn, []string{attr}))) {
return ldap.LDAPResultInsufficientAccessRights, nil
}
// If we are changing ATTR_MEMBER, rewrite all values to canonical form
if strings.EqualFold(attr, ATTR_MEMBER) {
for i := range changeValues {
canonical_val, err := server.checkDN(changeValues[i], false)
if err != nil {
return ldap.LDAPResultInvalidDNSyntax, err
}
changeValues[i] = canonical_val
}
}
// If we don't yet have a new value for this attr,
// but one existed before, initialize entry[attr] to the old value
// so that later on what we do is simply modify entry[attr] in place
// (this allows to handle sequences of several changes on the same attr)
if _, ok := entry[attr]; !ok {
if _, ok := prevEntry[attr]; ok {
entry[attr] = prevEntry[attr]
}
}
// Apply effective modification on entry[attr]
if change.Operation() == ldap.ModifyRequestChangeOperationAdd {
for _, val := range changeValues {
if !listContains(entry[attr], val) {
entry[attr] = append(entry[attr], val)
if strings.EqualFold(attr, ATTR_MEMBER) {
addMembers = append(addMembers, val)
}
}
}
} else if change.Operation() == ldap.ModifyRequestChangeOperationDelete {
if len(changeValues) == 0 {
// Delete everything
if strings.EqualFold(attr, ATTR_MEMBER) {
delMembers = append(delMembers, entry[attr]...)
}
entry[attr] = []string{}
} else {
// Delete only those specified
newList := []string{}
for _, prevVal := range entry[attr] {
if !listContains(changeValues, prevVal) {
newList = append(newList, prevVal)
} else {
if strings.EqualFold(attr, ATTR_MEMBER) {
delMembers = append(delMembers, prevVal)
}
}
}
entry[attr] = newList
}
} else if change.Operation() == ldap.ModifyRequestChangeOperationReplace {
if strings.EqualFold(attr, ATTR_MEMBER) {
for _, newMem := range changeValues {
if !listContains(entry[attr], newMem) {
addMembers = append(addMembers, newMem)
}
}
for _, prevMem := range entry[attr] {
if !listContains(changeValues, prevMem) {
delMembers = append(delMembers, prevMem)
}
}
}
entry[attr] = changeValues
}
}
// Check that added members actually exist
for i := range addMembers {
exists, err := server.objectExists(addMembers[i])
if err != nil {
return ldap.LDAPResultOperationsError, err
}
if !exists {
return ldap.LDAPResultNoSuchObject, fmt.Errorf(
"Cannot add member %s, it does not exist", addMembers[i])
}
}
for k, v := range entry {
if strings.EqualFold(k, ATTR_OBJECTCLASS) && len(v) == 0 {
return ldap.LDAPResultInsufficientAccessRights, fmt.Errorf(
"Cannot remove all objectclass values")
}
}
// Now, the modification has been processed and accepted and we want to commit it
entry[ATTR_MODIFIERSNAME] = []string{state.login.user}
entry[ATTR_MODIFYTIMESTAMP] = []string{genTimestamp()}
// Save the edited values
err = server.putAttributes(dn, entry)
if err != nil {
return ldap.LDAPResultOperationsError, err
}
// ~~ from this point on, our operation succeeded ~~
// ~~ future errors cause inconsistencies in the DB and are logged ~~
// Update memberOf for added members and deleted members
for _, addMem := range addMembers {
server.memberOfAdd(addMem, dn)
}
for _, delMem := range delMembers {
server.memberOfRemove(delMem, dn)
}
return ldap.LDAPResultSuccess, nil
}