providers/ldap: Added auto-generated uidNumber and guidNumber generated attributes for use with SSSD and similar software. (#1138)

* Added auto-generated uidNumber and guidNumber generated attributes for
use with SSSD and similar software.

The starting number for uid/gid can be configured iva environtment
variables and is by default 2000 which should work fine for most instances unless there are more than
999 local accounts on the server/computer.

The uidNumber is just the users Pk + the starting number.
The guidNumber is calculated by the last couple of bytes in the uuid of
the group + the starting number, this should have a low enough chance
for collisions that it's going to be fine for most use cases.

I have not added any interface stuff for configuring the environment variables as I couldn't really find my way around all the places I'd have to edit to add it and the default values should in my opinion be fine for 99% use cases.

* Add a 'fake' primary group for each user

* First attempt att adding config to interface

* Updated API to support new fields

* Refactor code, update documentation and remove obsolete comment

Simplify `GetRIDForGroup`, was a bit overcomplicated before.

Add an additional class/struct `LDAPGroup` which is the new argument
for `pi.GroupEntry` and util functions to create `LDAPGroup` from api.Group and api.User

Add proper support in the interface for changing gidNumber and uidNumber starting points

* make lint-fix for the migration files

Pipfile

@@ -47,6 +47,7 @@ xmlsec = "*"
 duo-client = "*"
 ua-parser = "*"
 deepmerge = "*"
+colorama = "*"
 
 [requires]
 python_version = "3.9"

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "f90d9fb4713eaf9c5ffe6a3858e64843670f79ab5007e7debf914c1f094c8d63"
+            "sha256": "e4f2e57bd5c709809515ab2b95eb3f5fa337d4a9334f4110a24bf28c3f9d5f8f"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -288,6 +288,14 @@
             ],
             "version": "==0.2.0"
         },
+        "colorama": {
+            "hashes": [
+                "sha256:5941b2b48a20143d2267e95b1c2a7603ce057ee39fd88e7329b0c292aa16869b",
+                "sha256:9f47eda37229f68eee03b24b9748937c7dc3868f906e8ba69fbcbdd3bc5dc3e2"
+            ],
+            "index": "pypi",
+            "version": "==0.4.4"
+        },
         "constantly": {
             "hashes": [
                 "sha256:586372eb92059873e29eba4f9dec8381541b4d3834660707faf8ba59146dfc35",

authentik/providers/ldap/api.py

@@ -19,6 +19,8 @@ class LDAPProviderSerializer(ProviderSerializer):
             "search_group",
             "certificate",
             "tls_server_name",
+            "uid_start_number",
+            "gid_start_number",
         ]
 
 
@@ -48,6 +50,8 @@ class LDAPOutpostConfigSerializer(ModelSerializer):
             "search_group",
             "certificate",
             "tls_server_name",
+            "uid_start_number",
+            "gid_start_number",
         ]
 
 

authentik/providers/ldap/migrations/0004_auto_20210713_2115.py

@@ -0,0 +1,29 @@
+# Generated by Django 3.2.5 on 2021-07-13 21:15
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("authentik_providers_ldap", "0003_auto_20210713_1138"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="ldapprovider",
+            name="gid_start_number",
+            field=models.IntegerField(
+                default=2000,
+                help_text="The start for gidNumbers, this number is added to a number generated from the group.Pk to make sure that the numbers aren't too low for POSIX groups. Default is 2000 to ensure that we don't collide with local groups gidNumber",
+            ),
+        ),
+        migrations.AddField(
+            model_name="ldapprovider",
+            name="uid_start_number",
+            field=models.IntegerField(
+                default=2000,
+                help_text="The start for uidNumbers, this number is added to the user.Pk to make sure that the numbers aren't too low for POSIX users. Default is 2000 to ensure that we don't collide with local users uidNumber",
+            ),
+        ),
+    ]

authentik/providers/ldap/migrations/0005_alter_ldapprovider_gid_start_number.py

@@ -0,0 +1,21 @@
+# Generated by Django 3.2.5 on 2021-07-14 06:49
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("authentik_providers_ldap", "0004_auto_20210713_2115"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="ldapprovider",
+            name="gid_start_number",
+            field=models.IntegerField(
+                default=4000,
+                help_text="The start for gidNumbers, this number is added to a number generated from the group.Pk to make sure that the numbers aren't too low for POSIX groups. Default is 4000 to ensure that we don't collide with local groups or users primary groups gidNumber",
+            ),
+        ),
+    ]

authentik/providers/ldap/models.py

@@ -40,6 +40,22 @@ class LDAPProvider(OutpostModel, Provider):
         blank=True,
     )
 
+    uid_start_number = models.IntegerField(
+        default=2000,
+        help_text=_(
+            "The start for uidNumbers, this number is added to the user.Pk to make sure that the numbers aren't too low for POSIX users. "
+            "Default is 2000 to ensure that we don't collide with local users uidNumber"
+        ),
+    )
+
+    gid_start_number = models.IntegerField(
+        default=4000,
+        help_text=_(
+            "The start for gidNumbers, this number is added to a number generated from the group.Pk to make sure that the numbers aren't too low for POSIX groups. "
+            "Default is 4000 to ensure that we don't collide with local groups or users primary groups gidNumber"
+        ),
+    )
+
     @property
     def launch_url(self) -> Optional[str]:
         """LDAP never has a launch URL"""

outpost/pkg/ldap/api.go

@@ -37,8 +37,10 @@ func (ls *LDAPServer) Refresh() error {
 			boundUsersMutex:     sync.RWMutex{},
 			boundUsers:          make(map[string]UserFlags),
 			s:                   ls,
-			log:                 logger,
+			log:                 log.WithField("logger", "authentik.outpost.ldap").WithField("provider", provider.Name),
 			tlsServerName:       provider.TlsServerName,
+			uidStartNumber:		 *provider.UidStartNumber,
+			gidStartNumber:		 *provider.GidStartNumber,
 		}
 		if provider.Certificate.Get() != nil {
 			logger.WithField("provider", provider.Name).Debug("Enabling TLS")

outpost/pkg/ldap/instance_search.go

@@ -54,8 +54,18 @@ func (pi *ProviderInstance) Search(bindDN string, searchReq ldap.SearchRequest,
 			return ldap.ServerSearchResult{ResultCode: ldap.LDAPResultOperationsError}, fmt.Errorf("API Error: %s", err)
 		}
 		pi.log.WithField("count", len(groups.Results)).Trace("Got results from API")
+
 		for _, g := range groups.Results {
-			entries = append(entries, pi.GroupEntry(g))
+			entries = append(entries, pi.GroupEntry(pi.APIGroupToLDAPGroup(g)))
+		}
+
+		users, _, err := pi.s.ac.Client.CoreApi.CoreUsersList(context.Background()).Execute()
+		if err != nil {
+			return ldap.ServerSearchResult{ResultCode: ldap.LDAPResultOperationsError}, fmt.Errorf("API Error: %s", err)
+		}
+
+		for _, u := range users.Results {
+			entries = append(entries, pi.GroupEntry(pi.APIUserToLDAPGroup(u)))
 		}
 	case UserObjectClass, "":
 		users, _, err := pi.s.ac.Client.CoreApi.CoreUsersList(context.Background()).Execute()
@@ -96,6 +106,14 @@ func (pi *ProviderInstance) UserEntry(u api.User) *ldap.Entry {
 			Name:   "objectClass",
 			Values: []string{UserObjectClass, "organizationalPerson", "goauthentik.io/ldap/user"},
 		},
+		{
+			Name:   "uidNumber",
+			Values: []string{ pi.GetUidNumber(u) },
+		},
+		{
+			Name:   "gidNumber",
+			Values: []string{ pi.GetUidNumber(u) },
+		},
 	}
 
 	attrs = append(attrs, &ldap.EntryAttribute{Name: "memberOf", Values: pi.GroupsForUser(u)})
@@ -114,26 +132,40 @@ func (pi *ProviderInstance) UserEntry(u api.User) *ldap.Entry {
 	return &ldap.Entry{DN: dn, Attributes: attrs}
 }
 
-func (pi *ProviderInstance) GroupEntry(g api.Group) *ldap.Entry {
+func (pi *ProviderInstance) GroupEntry(g LDAPGroup) *ldap.Entry {
 	attrs := []*ldap.EntryAttribute{
 		{
 			Name:   "cn",
-			Values: []string{g.Name},
+			Values: []string{g.cn},
 		},
 		{
 			Name:   "uid",
-			Values: []string{string(g.Pk)},
+			Values: []string{g.uid},
 		},
 		{
-			Name:   "objectClass",
+			Name:   "gidNumber",
-			Values: []string{GroupObjectClass, "goauthentik.io/ldap/group"},
+			Values: []string{ g.gidNumber },
 		},
 	}
-	attrs = append(attrs, &ldap.EntryAttribute{Name: "member", Values: pi.UsersForGroup(g)})
-	attrs = append(attrs, &ldap.EntryAttribute{Name: "goauthentik.io/ldap/superuser", Values: []string{BoolToString(*g.IsSuperuser)}})
 
-	attrs = append(attrs, AKAttrsToLDAP(g.Attributes)...)
+	if (g.isVirtualGroup) {
+		attrs = append(attrs, &ldap.EntryAttribute{
+			Name: "objectClass",
+			Values: []string{GroupObjectClass, "goauthentik.io/ldap/group", "goauthentik.io/ldap/virtual-group"},
+		})
+	} else {
+		attrs = append(attrs, &ldap.EntryAttribute{
+			Name: "objectClass",
+			Values: []string{GroupObjectClass, "goauthentik.io/ldap/group"},
+		})
+	}
 
-	dn := pi.GetGroupDN(g)
+	attrs = append(attrs, &ldap.EntryAttribute{Name: "member", Values: g.member})
-	return &ldap.Entry{DN: dn, Attributes: attrs}
+	attrs = append(attrs, &ldap.EntryAttribute{Name: "goauthentik.io/ldap/superuser", Values: []string{BoolToString(g.isSuperuser)}})
+
+	if (g.akAttributes != nil) {
+		attrs = append(attrs, AKAttrsToLDAP(g.akAttributes)...)
+	}
+
+	return &ldap.Entry{DN: g.dn, Attributes: attrs}
 }

outpost/pkg/ldap/ldap.go

@@ -32,6 +32,9 @@ type ProviderInstance struct {
 	searchAllowedGroups []*strfmt.UUID
 	boundUsersMutex     sync.RWMutex
 	boundUsers          map[string]UserFlags
+
+	uidStartNumber int32
+	gidStartNumber int32
 }
 
 type UserFlags struct {
@@ -47,6 +50,17 @@ type LDAPServer struct {
 	providers   []*ProviderInstance
 }
 
+type LDAPGroup struct {
+	dn string
+	cn string
+	uid string
+	gidNumber string
+	member []string
+	isSuperuser bool
+	isVirtualGroup bool
+	akAttributes interface{}
+}
+
 func NewServer(ac *ak.APIController) *LDAPServer {
 	s := ldap.NewServer()
 	s.EnforceLDAP = true

outpost/pkg/ldap/utils.go

@@ -2,6 +2,9 @@ package ldap
 
 import (
 	"fmt"
+	"strings"
+	"math/big"
+	"strconv"
 	"reflect"
 
 	"github.com/nmcclain/ldap"
@@ -77,6 +80,34 @@ func (pi *ProviderInstance) UsersForGroup(group api.Group) []string {
 	return users
 }
 
+func (pi *ProviderInstance) APIGroupToLDAPGroup(g api.Group) LDAPGroup {
+	return LDAPGroup{
+		dn:				pi.GetGroupDN(g),
+		cn:				g.Name,
+		uid:			string(g.Pk),
+		gidNumber:		pi.GetGidNumber(g),
+		member:			pi.UsersForGroup(g),
+		isVirtualGroup:	false,
+		isSuperuser:	*g.IsSuperuser,
+		akAttributes:	g.Attributes,
+	}
+}
+
+func (pi *ProviderInstance) APIUserToLDAPGroup(u api.User) LDAPGroup {
+	dn := fmt.Sprintf("cn=%s,%s", u.Username, pi.GroupDN)
+
+	return LDAPGroup{
+		dn:				dn,
+		cn:				u.Username,
+		uid:			u.Uid,
+		gidNumber:		pi.GetUidNumber(u),
+		member:			[]string{dn},
+		isVirtualGroup:	true,
+		isSuperuser:	false,
+		akAttributes:	nil,
+	}
+}
+
 func (pi *ProviderInstance) GetUserDN(user string) string {
 	return fmt.Sprintf("cn=%s,%s", user, pi.UserDN)
 }
@@ -84,3 +115,26 @@ func (pi *ProviderInstance) GetUserDN(user string) string {
 func (pi *ProviderInstance) GetGroupDN(group api.Group) string {
 	return fmt.Sprintf("cn=%s,%s", group.Name, pi.GroupDN)
 }
+
+func (pi *ProviderInstance) GetUidNumber(user api.User) string {
+	return strconv.FormatInt(int64(pi.uidStartNumber + user.Pk), 10)
+}
+
+func (pi *ProviderInstance) GetGidNumber(group api.Group) string {
+	return strconv.FormatInt(int64(pi.gidStartNumber + pi.GetRIDForGroup(group.Pk)), 10)
+}
+
+func (pi *ProviderInstance) GetRIDForGroup(uid string) int32 {
+    var i big.Int
+    i.SetString(strings.Replace(uid, "-", "", -1), 16)
+	intStr := i.String()
+
+	// Get the last 5 characters/digits of the int-version of the UUID
+	gid, err := strconv.Atoi(intStr[len(intStr)-5:])
+
+	if err != nil {
+		panic(err)
+	}
+
+	return int32(gid)
+}

schema.yml

@@ -20497,6 +20497,10 @@ components:
           nullable: true
         tls_server_name:
           type: string
+        uid_start_number:
+          type: integer
+        gid_start_number:
+          type: integer
       required:
       - application_slug
       - bind_flow_slug
@@ -20615,6 +20619,10 @@ components:
           nullable: true
         tls_server_name:
           type: string
+        uid_start_number:
+          type: integer
+        gid_start_number:
+          type: integer
       required:
       - assigned_application_name
       - assigned_application_slug
@@ -20654,6 +20662,10 @@ components:
           nullable: true
         tls_server_name:
           type: string
+        uid_start_number:
+          type: integer
+        gid_start_number:
+          type: integer
       required:
       - authorization_flow
       - name
@@ -24996,6 +25008,10 @@ components:
           nullable: true
         tls_server_name:
           type: string
+        uid_start_number:
+          type: integer
+        gid_start_number:
+          type: integer
     PatchedLDAPSourceRequest:
       type: object
       description: LDAP Source Serializer

web/src/pages/providers/ldap/LDAPProviderForm.ts

@@ -92,7 +92,7 @@ export class LDAPProviderFormPage extends ModelForm<LDAPProvider, number> {
                     </ak-form-element-horizontal>
                     <ak-form-element-horizontal
                         label=${t`TLS Server name`}
-                        name="baseDn">
+                        name="tlsServerName">
                         <input type="text" value="${first(this.instance?.tlsServerName, "")}" class="pf-c-form-control">
                         <p class="pf-c-form__helper-text">${t`Server name for which this provider's certificate is valid for.`}</p>
                     </ak-form-element-horizontal>
@@ -111,6 +111,20 @@ export class LDAPProviderFormPage extends ModelForm<LDAPProvider, number> {
                             }), html`<option>${t`Loading...`}</option>`)}
                         </select>
                     </ak-form-element-horizontal>
+                    <ak-form-element-horizontal
+                        label=${t`UID start number`}
+                        ?required=${true}
+                        name="uidStartNumber">
+                        <input type="number" value="${first(this.instance?.uidStartNumber, 2000)}" class="pf-c-form-control" required>
+                        <p class="pf-c-form__helper-text">${t`The start for uidNumbers, this number is added to the user.Pk to make sure that the numbers aren't too low for POSIX users. Default is 2000 to ensure that we don't collide with local users uidNumber`}</p>
+                    </ak-form-element-horizontal>
+                    <ak-form-element-horizontal
+                        label=${t`GID start number`}
+                        ?required=${true}
+                        name="gidStartNumber">
+                        <input type="number" value="${first(this.instance?.gidStartNumber, 4000)}" class="pf-c-form-control" required>
+                        <p class="pf-c-form__helper-text">${t`The start for gidNumbers, this number is added to a number generated from the group.Pk to make sure that the numbers aren't too low for POSIX groups. Default is 4000 to ensure that we don't collide with local groups or users primary groups gidNumber`}</p>
+                    </ak-form-element-horizontal>
                 </div>
             </ak-form-group>
         </form>`;

website/docs/outposts/ldap/ldap.md

@@ -33,6 +33,7 @@ The following fields are currently sent for users:
 
 - `cn`: User's username
 - `uid`: Unique user identifier
+- `uidNumber`: A unique numeric identifier for the user
 - `name`: User's name
 - `displayName`: User's name
 - `mail`: User's email address
@@ -48,12 +49,16 @@ The following fields are current set for groups:
 
 - `cn`: The group's name
 - `uid`: Unique group identifier
-- `member`: A list of all DNs of the group's members
+- `gidNumber`: A unique numeric identifier for the group
+- `member`: A list of all DNs of the groups members
 - `objectClass`: A list of these strings:
   - "group"
   - "goauthentik.io/ldap/group"
 
-**Additionally**, for both users and groups, any attributes you set are also present as LDAP Attributes.
+A virtual group is also created for each user, they have the same fields as groups but have an additional objectClass: `goauthentik.io/ldap/group`.  
+The virtual groups gidNumber is equal to the uidNumber of the user.
+
+**Additionally**, for both users and (non-virtual) groups, any attributes you set are also present as LDAP Attributes.
 
 ## SSL