2024-12-22 13:34:15 +03:00 · 2023-12-08 16:38:21 +13:00 · 2023-12-08 16:38:21 +13:00 · 080a62bba8
commit 080a62bba8
parent f6bb2d4010
5 changed files with 1779 additions and 0 deletions
--- a/python/samba/gkdi.py
+++ b/python/samba/gkdi.py
@ -0,0 +1,397 @@
+# Unix SMB/CIFS implementation.
+# Copyright (C) Catalyst.Net Ltd 2023
+#
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+
+"""Group Key Distribution Service module"""
+
+from enum import Enum
+from functools import total_ordering
+from typing import Final, Optional, Tuple
+
+from cryptography.hazmat.primitives import hashes
+
+from samba import _glue
+from samba.dcerpc import gkdi, misc
+from samba.ndr import ndr_pack, ndr_unpack
+from samba.nt_time import NtTime, NtTimeDelta
+
+
+uint64_max: Final[int] = 2**64 - 1
+
+L1_KEY_ITERATION: Final[int] = _glue.GKDI_L1_KEY_ITERATION
+L2_KEY_ITERATION: Final[int] = _glue.GKDI_L2_KEY_ITERATION
+KEY_CYCLE_DURATION: Final[NtTimeDelta] = _glue.GKDI_KEY_CYCLE_DURATION
+MAX_CLOCK_SKEW: Final[NtTimeDelta] = _glue.GKDI_MAX_CLOCK_SKEW
+
+KEY_LEN_BYTES: Final = 64
+
+
+class Algorithm(Enum):
+    SHA1 = "SHA1"
+    SHA256 = "SHA256"
+    SHA384 = "SHA384"
+    SHA512 = "SHA512"
+
+    def algorithm(self) -> hashes.HashAlgorithm:
+        if self is Algorithm.SHA1:
+            return hashes.SHA1()
+
+        if self is Algorithm.SHA256:
+            return hashes.SHA256()
+
+        if self is Algorithm.SHA384:
+            return hashes.SHA384()
+
+        if self is Algorithm.SHA512:
+            return hashes.SHA512()
+
+        raise RuntimeError("unknown hash algorithm {self}")
+
+    def __repr__(self) -> str:
+        return str(self)
+
+    @staticmethod
+    def from_kdf_parameters(kdf_param: Optional[bytes]) -> "Algorithm":
+        if not kdf_param:
+            return Algorithm.SHA256  # the default used by Windows.
+
+        kdf_parameters = ndr_unpack(gkdi.KdfParameters, kdf_param)
+        return Algorithm(kdf_parameters.hash_algorithm)
+
+
+class GkidType(Enum):
+    DEFAULT = object()
+    L0_SEED_KEY = object()
+    L1_SEED_KEY = object()
+    L2_SEED_KEY = object()
+
+    def description(self) -> str:
+        if self is GkidType.DEFAULT:
+            return "a default GKID"
+
+        if self is GkidType.L0_SEED_KEY:
+            return "an L0 seed key"
+
+        if self is GkidType.L1_SEED_KEY:
+            return "an L1 seed key"
+
+        if self is GkidType.L2_SEED_KEY:
+            return "an L2 seed key"
+
+        raise RuntimeError("unknown GKID type {self}")
+
+
+class InvalidDerivation(Exception):
+    pass
+
+
+class UndefinedStartTime(Exception):
+    pass
+
+
+@total_ordering
+class Gkid:
+    __slots__ = ["_l0_idx", "_l1_idx", "_l2_idx"]
+
+    max_l0_idx: Final = 0x7FFF_FFFF
+
+    def __init__(self, l0_idx: int, l1_idx: int, l2_idx: int) -> None:
+        if not -1 <= l0_idx <= Gkid.max_l0_idx:
+            raise ValueError(f"L0 index {l0_idx} out of range")
+
+        if not -1 <= l1_idx < L1_KEY_ITERATION:
+            raise ValueError(f"L1 index {l1_idx} out of range")
+
+        if not -1 <= l2_idx < L2_KEY_ITERATION:
+            raise ValueError(f"L2 index {l2_idx} out of range")
+
+        if l0_idx == -1 and l1_idx != -1:
+            raise ValueError("invalid combination of negative and non‐negative indices")
+
+        if l1_idx == -1 and l2_idx != -1:
+            raise ValueError("invalid combination of negative and non‐negative indices")
+
+        self._l0_idx = l0_idx
+        self._l1_idx = l1_idx
+        self._l2_idx = l2_idx
+
+    @property
+    def l0_idx(self) -> int:
+        return self._l0_idx
+
+    @property
+    def l1_idx(self) -> int:
+        return self._l1_idx
+
+    @property
+    def l2_idx(self) -> int:
+        return self._l2_idx
+
+    def gkid_type(self) -> GkidType:
+        if self.l0_idx == -1:
+            return GkidType.DEFAULT
+
+        if self.l1_idx == -1:
+            return GkidType.L0_SEED_KEY
+
+        if self.l2_idx == -1:
+            return GkidType.L1_SEED_KEY
+
+        return GkidType.L2_SEED_KEY
+
+    def wrapped_l1_idx(self) -> int:
+        if self.l1_idx == -1:
+            return L1_KEY_ITERATION
+
+        return self.l1_idx
+
+    def wrapped_l2_idx(self) -> int:
+        if self.l2_idx == -1:
+            return L2_KEY_ITERATION
+
+        return self.l2_idx
+
+    def derive_l1_seed_key(self) -> "Gkid":
+        gkid_type = self.gkid_type()
+        if (
+            gkid_type is not GkidType.L0_SEED_KEY
+            and gkid_type is not GkidType.L1_SEED_KEY
+        ):
+            raise InvalidDerivation(
+                "Invalid attempt to derive an L1 seed key from"
+                f" {gkid_type.description()}"
+            )
+
+        if self.l1_idx == 0:
+            raise InvalidDerivation("No further derivation of L1 seed keys is possible")
+
+        return Gkid(self.l0_idx, self.wrapped_l1_idx() - 1, self.l2_idx)
+
+    def derive_l2_seed_key(self) -> "Gkid":
+        gkid_type = self.gkid_type()
+        if (
+            gkid_type is not GkidType.L1_SEED_KEY
+            and gkid_type is not GkidType.L2_SEED_KEY
+        ):
+            raise InvalidDerivation(
+                f"Attempt to derive an L2 seed key from {gkid_type.description()}"
+            )
+
+        if self.l2_idx == 0:
+            raise InvalidDerivation("No further derivation of L2 seed keys is possible")
+
+        return Gkid(self.l0_idx, self.l1_idx, self.wrapped_l2_idx() - 1)
+
+    def __str__(self) -> str:
+        return f"Gkid({self.l0_idx}, {self.l1_idx}, {self.l2_idx})"
+
+    def __repr__(self) -> str:
+        cls = type(self)
+        return (
+            f"{cls.__qualname__}({repr(self.l0_idx)}, {repr(self.l1_idx)},"
+            f" {repr(self.l2_idx)})"
+        )
+
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, Gkid):
+            return NotImplemented
+
+        return (self.l0_idx, self.l1_idx, self.l2_idx) == (
+            other.l0_idx,
+            other.l1_idx,
+            other.l2_idx,
+        )
+
+    def __lt__(self, other: object) -> bool:
+        if not isinstance(other, Gkid):
+            return NotImplemented
+
+        def as_tuple(gkid: Gkid) -> Tuple[int, int, int]:
+            l0_idx, l1_idx, l2_idx = gkid.l0_idx, gkid.l1_idx, gkid.l2_idx
+
+            # DEFAULT is considered less than everything else, so that the
+            # lexical ordering requirement in [MS-GKDI] 3.1.4.1.3 (GetKey) makes
+            # sense.
+            if gkid.gkid_type() is not GkidType.DEFAULT:
+                # Use the wrapped indices so that L1 seed keys are considered
+                # greater than their children L2 seed keys, and L0 seed keys are
+                # considered greater than their children L1 seed keys.
+                l1_idx = gkid.wrapped_l1_idx()
+                l2_idx = gkid.wrapped_l2_idx()
+
+            return l0_idx, l1_idx, l2_idx
+
+        return as_tuple(self) < as_tuple(other)
+
+    def __hash__(self) -> int:
+        return hash((self.l0_idx, self.l1_idx, self.l2_idx))
+
+    @staticmethod
+    def default() -> "Gkid":
+        return Gkid(-1, -1, -1)
+
+    @staticmethod
+    def l0_seed_key(l0_idx: int) -> "Gkid":
+        return Gkid(l0_idx, -1, -1)
+
+    @staticmethod
+    def l1_seed_key(l0_idx: int, l1_idx: int) -> "Gkid":
+        return Gkid(l0_idx, l1_idx, -1)
+
+    @staticmethod
+    def from_nt_time(nt_time: NtTime) -> "Gkid":
+        l0 = nt_time // (L1_KEY_ITERATION * L2_KEY_ITERATION * KEY_CYCLE_DURATION)
+        l1 = (
+            nt_time
+            % (L1_KEY_ITERATION * L2_KEY_ITERATION * KEY_CYCLE_DURATION)
+            // (L2_KEY_ITERATION * KEY_CYCLE_DURATION)
+        )
+        l2 = nt_time % (L2_KEY_ITERATION * KEY_CYCLE_DURATION) // KEY_CYCLE_DURATION
+
+        return Gkid(l0, l1, l2)
+
+    def start_nt_time(self) -> NtTime:
+        gkid_type = self.gkid_type()
+        if gkid_type is not GkidType.L2_SEED_KEY:
+            raise UndefinedStartTime(
+                f"{gkid_type.description()} has no defined start time"
+            )
+
+        start_time = NtTime(
+            (
+                self.l0_idx * L1_KEY_ITERATION * L2_KEY_ITERATION
+                + self.l1_idx * L2_KEY_ITERATION
+                + self.l2_idx
+            )
+            * KEY_CYCLE_DURATION
+        )
+
+        if not 0 <= start_time <= uint64_max:
+            raise OverflowError(f"start time {start_time} out of range")
+
+        return start_time
+
+
+class SeedKeyPair:
+    __slots__ = ["l1_key", "l2_key", "gkid", "hash_algorithm", "root_key_id"]
+
+    def __init__(
+        self,
+        l1_key: Optional[bytes],
+        l2_key: Optional[bytes],
+        gkid: Gkid,
+        hash_algorithm: Algorithm,
+        root_key_id: misc.GUID,
+    ) -> None:
+        if l1_key is not None and len(l1_key) != KEY_LEN_BYTES:
+            raise ValueError(f"L1 key ({repr(l1_key)}) must be {KEY_LEN_BYTES} bytes")
+        if l2_key is not None and len(l2_key) != KEY_LEN_BYTES:
+            raise ValueError(f"L2 key ({repr(l2_key)}) must be {KEY_LEN_BYTES} bytes")
+
+        self.l1_key = l1_key
+        self.l2_key = l2_key
+        self.gkid = gkid
+        self.hash_algorithm = hash_algorithm
+        self.root_key_id = root_key_id
+
+    def __str__(self) -> str:
+        l1_key_hex = None if self.l1_key is None else self.l1_key.hex()
+        l2_key_hex = None if self.l2_key is None else self.l2_key.hex()
+
+        return (
+            f"SeedKeyPair(L1Key({l1_key_hex}), L2Key({l2_key_hex}), {self.gkid},"
+            f" {self.root_key_id}, {self.hash_algorithm})"
+        )
+
+    def __repr__(self) -> str:
+        cls = type(self)
+        return (
+            f"{cls.__qualname__}({repr(self.l1_key)}, {repr(self.l2_key)},"
+            f" {repr(self.gkid)}, {repr(self.hash_algorithm)},"
+            f" {repr(self.root_key_id)})"
+        )
+
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, SeedKeyPair):
+            return NotImplemented
+
+        return (
+            self.l1_key,
+            self.l2_key,
+            self.gkid,
+            self.hash_algorithm,
+            self.root_key_id,
+        ) == (
+            other.l1_key,
+            other.l2_key,
+            other.gkid,
+            other.hash_algorithm,
+            other.root_key_id,
+        )
+
+    def __hash__(self) -> int:
+        return hash((
+            self.l1_key,
+            self.l2_key,
+            self.gkid,
+            self.hash_algorithm,
+            ndr_pack(self.root_key_id),
+        ))
+
+
+class GroupKey:
+    __slots__ = ["gkid", "key", "hash_algorithm", "root_key_id"]
+
+    def __init__(
+        self, key: bytes, gkid: Gkid, hash_algorithm: Algorithm, root_key_id: misc.GUID
+    ) -> None:
+        if key is not None and len(key) != KEY_LEN_BYTES:
+            raise ValueError(f"Key ({repr(key)}) must be {KEY_LEN_BYTES} bytes")
+
+        self.key = key
+        self.gkid = gkid
+        self.hash_algorithm = hash_algorithm
+        self.root_key_id = root_key_id
+
+    def __str__(self) -> str:
+        return (
+            f"GroupKey(Key({self.key.hex()}), {self.gkid}, {self.hash_algorithm},"
+            f" {self.root_key_id})"
+        )
+
+    def __repr__(self) -> str:
+        cls = type(self)
+        return (
+            f"{cls.__qualname__}({repr(self.key)}, {repr(self.gkid)},"
+            f" {repr(self.hash_algorithm)}, {repr(self.root_key_id)})"
+        )
+
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, GroupKey):
+            return NotImplemented
+
+        return (self.key, self.gkid, self.hash_algorithm, self.root_key_id) == (
+            other.key,
+            other.gkid,
+            other.hash_algorithm,
+            other.root_key_id,
+        )
+
+    def __hash__(self) -> int:
+        return hash(
+            (self.key, self.gkid, self.hash_algorithm, ndr_pack(self.root_key_id))
+        )
--- a/python/samba/tests/gkdi.py
+++ b/python/samba/tests/gkdi.py
@ -0,0 +1,644 @@
+#
+# Helper classes for testing the Group Key Distribution Service.
+#
+# Copyright (C) Catalyst.Net Ltd 2023
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+
+import sys
+import os
+
+sys.path.insert(0, "bin/python")
+os.environ["PYTHONUNBUFFERED"] = "1"
+
+import datetime
+import secrets
+from typing import Final, NewType, Optional, Tuple, Union
+
+import ldb
+
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.kdf.kbkdf import CounterLocation, KBKDFHMAC, Mode
+
+from samba import (
+    HRES_E_INVALIDARG,
+    HRES_NTE_BAD_KEY,
+    HRES_NTE_NO_KEY,
+    ntstatus,
+    NTSTATUSError,
+    werror,
+)
+from samba.credentials import Credentials
+from samba.dcerpc import gkdi, misc
+from samba.gkdi import (
+    Algorithm,
+    Gkid,
+    GkidType,
+    GroupKey,
+    KEY_CYCLE_DURATION,
+    KEY_LEN_BYTES,
+    MAX_CLOCK_SKEW,
+    SeedKeyPair,
+)
+from samba.ndr import ndr_pack, ndr_unpack
+from samba.nt_time import (
+    nt_time_from_datetime,
+    NtTime,
+    NtTimeDelta,
+    timedelta_from_nt_time_delta,
+)
+from samba.param import LoadParm
+from samba.samdb import SamDB
+
+from samba.tests import delete_force, TestCase
+
+
+HResult = NewType("HResult", int)
+RootKey = NewType("RootKey", ldb.Message)
+
+
+ROOT_KEY_START_TIME: Final = NtTime(KEY_CYCLE_DURATION + MAX_CLOCK_SKEW)
+
+
+class GetKeyError(Exception):
+    def __init__(self, status: HResult, message: str):
+        super().__init__(status, message)
+
+
+class GkdiBaseTest(TestCase):
+    # This is the NDR‐encoded security descriptor O:SYD:(A;;FRFW;;;S-1-5-9).
+    gmsa_sd = (
+        b"\x01\x00\x04\x800\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+        b"\x14\x00\x00\x00\x02\x00\x1c\x00\x01\x00\x00\x00\x00\x00\x14\x00"
+        b"\x9f\x01\x12\x00\x01\x01\x00\x00\x00\x00\x00\x05\t\x00\x00\x00"
+        b"\x01\x01\x00\x00\x00\x00\x00\x05\x12\x00\x00\x00"
+    )
+
+    @staticmethod
+    def current_time(offset: Optional[datetime.timedelta] = None) -> datetime.datetime:
+        if offset is None:
+            # Allow for clock skew.
+            offset = timedelta_from_nt_time_delta(MAX_CLOCK_SKEW)
+
+        current_time = datetime.datetime.now(tz=datetime.timezone.utc)
+        return current_time + offset
+
+    def current_nt_time(self, offset: Optional[datetime.timedelta] = None) -> NtTime:
+        return nt_time_from_datetime(self.current_time(offset))
+
+    def current_gkid(self, offset: Optional[datetime.timedelta] = None) -> Gkid:
+        return Gkid.from_nt_time(self.current_nt_time(offset))
+
+    def gkdi_connect(
+        self, host: str, lp: LoadParm, server_creds: Credentials
+    ) -> gkdi.gkdi:
+        try:
+            return gkdi.gkdi(f"ncacn_ip_tcp:{host}[seal]", lp, server_creds)
+        except NTSTATUSError as err:
+            if err.args[0] == ntstatus.NT_STATUS_PORT_UNREACHABLE:
+                self.fail(
+                    "Try starting the Microsoft Key Distribution Service (KdsSvc).\n"
+                    "In PowerShell, run:\n\tStart-Service -Name KdsSvc"
+                )
+
+            raise
+
+    def rpc_get_key(
+        self,
+        conn: gkdi.gkdi,
+        target_sd: bytes,
+        root_key_id: Optional[misc.GUID],
+        gkid: Gkid,
+    ) -> SeedKeyPair:
+        out_len, out, result = conn.GetKey(
+            list(target_sd), root_key_id, gkid.l0_idx, gkid.l1_idx, gkid.l2_idx
+        )
+        result_code, result_string = result
+        if (
+            root_key_id is None
+            and result_code & 0xFFFF == werror.WERR_TOO_MANY_OPEN_FILES
+        ):
+            self.fail(
+                "The server has given up selecting a root key because there are too"
+                " many keys (more than 1000) in the Master Root Keys container. Delete"
+                " some root keys and try again."
+            )
+        if result != (0, None):
+            raise GetKeyError(result_code, result_string)
+        self.assertEqual(len(out), out_len, "output len mismatch")
+
+        envelope = ndr_unpack(gkdi.GroupKeyEnvelope, bytes(out))
+
+        gkid = Gkid(envelope.l0_index, envelope.l1_index, envelope.l2_index)
+        l1_key = bytes(envelope.l1_key) if envelope.l1_key else None
+        l2_key = bytes(envelope.l2_key) if envelope.l2_key else None
+
+        hash_algorithm = Algorithm.from_kdf_parameters(bytes(envelope.kdf_parameters))
+
+        root_key_id = envelope.root_key_id
+
+        return SeedKeyPair(l1_key, l2_key, gkid, hash_algorithm, root_key_id)
+
+    def get_root_key_object(
+        self, samdb: SamDB, root_key_id: Optional[misc.GUID], gkid: Gkid
+    ) -> Tuple[RootKey, misc.GUID]:
+        """Return a root key object and its corresponding GUID.
+
+        *root_key_id* specifies the GUID of the root key object to return. It
+        can be ``None`` to indicate that the selected key should be the most
+        recently created key starting not after the time indicated by *gkid*.
+
+        Bear in mind as that the Microsoft Key Distribution Service caches root
+        keys, the most recently created key might not be the one that Windows
+        chooses."""
+
+        root_key_attrs = [
+            "cn",
+            "msKds-CreateTime",
+            "msKds-KDFAlgorithmID",
+            "msKds-KDFParam",
+            "msKds-RootKeyData",
+            "msKds-UseStartTime",
+            "msKds-Version",
+        ]
+
+        gkid_start_nt_time = gkid.start_nt_time()
+
+        exact_key_specified = root_key_id is not None
+        if exact_key_specified:
+            root_key_dn = self.get_root_key_container_dn(samdb)
+            root_key_dn.add_child(f"CN={root_key_id}")
+
+            try:
+                root_key_res = samdb.search(
+                    root_key_dn, scope=ldb.SCOPE_BASE, attrs=root_key_attrs
+                )
+            except ldb.LdbError as err:
+                if err.args[0] == ldb.ERR_NO_SUCH_OBJECT:
+                    raise GetKeyError(HRES_NTE_NO_KEY, "no such root key exists")
+
+                raise
+
+            root_key_object = root_key_res[0]
+        else:
+            root_keys = samdb.search(
+                self.get_root_key_container_dn(samdb),
+                scope=ldb.SCOPE_SUBTREE,
+                expression=f"(msKds-UseStartTime<={gkid_start_nt_time})",
+                attrs=root_key_attrs,
+            )
+            if not root_keys:
+                raise GetKeyError(
+                    HRES_NTE_NO_KEY, "no root keys exist at specified time"
+                )
+
+            def root_key_create_time(key: RootKey) -> NtTime:
+                create_time = key.get("msKds-CreateTime", idx=0)
+                if create_time is None:
+                    return NtTime(0)
+
+                return NtTime(int(create_time))
+
+            root_key_object = max(root_keys, key=root_key_create_time)
+
+            root_key_cn = root_key_object.get("cn", idx=0)
+            self.assertIsNotNone(root_key_cn)
+            root_key_id = misc.GUID(root_key_cn)
+
+        use_start_nt_time = NtTime(
+            int(root_key_object.get("msKds-UseStartTime", idx=0))
+        )
+        if use_start_nt_time == 0:
+            raise GetKeyError(HRES_NTE_BAD_KEY, "root key effective time is 0")
+        use_start_nt_time = NtTime(
+            use_start_nt_time - NtTimeDelta(KEY_CYCLE_DURATION + MAX_CLOCK_SKEW)
+        )
+
+        if exact_key_specified and not (0 <= use_start_nt_time <= gkid_start_nt_time):
+            raise GetKeyError(HRES_E_INVALIDARG, "root key is not yet valid")
+
+        return root_key_object, root_key_id
+
+    def validate_get_key_request(
+        self, gkid: Gkid, current_gkid: Gkid, root_key_specified: bool
+    ) -> None:
+        if gkid > current_gkid:
+            raise GetKeyError(
+                HRES_E_INVALIDARG, "invalid request for a key from the future"
+            )
+
+        gkid_type = gkid.gkid_type()
+        if gkid_type is GkidType.DEFAULT:
+            derived_from = (
+                " derived from the specified root key" if root_key_specified else ""
+            )
+            raise NotImplementedError(
+                f"The latest group key{derived_from} is being requested."
+            )
+
+        if gkid_type is not GkidType.L2_SEED_KEY:
+            raise GetKeyError(
+                HRES_E_INVALIDARG, f"invalid request for {gkid_type.description()}"
+            )
+
+    def get_key(
+        self,
+        samdb: SamDB,
+        target_sd: bytes,  # An NDR‐encoded valid security descriptor in self‐relative format.
+        root_key_id: Optional[misc.GUID],
+        gkid: Gkid,
+        *,
+        root_key_id_hint: Optional[misc.GUID] = None,
+        current_gkid: Optional[Gkid] = None,
+    ) -> SeedKeyPair:
+        """Emulate the ISDKey.GetKey() RPC method.
+
+        When passed a NULL root key ID, GetKey() may use a cached root key
+        rather than picking the most recently created applicable key as the
+        documentation implies. If it’s important to arrive at the same result as
+        Windows, pass a GUID in the *root_key_id_hint* parameter to specify a
+        particular root key to use."""
+
+        if current_gkid is None:
+            current_gkid = self.current_gkid()
+
+        root_key_specified = root_key_id is not None
+        if root_key_specified:
+            self.assertIsNone(
+                root_key_id_hint, "don’t provide both root key ID parameters"
+            )
+
+        self.validate_get_key_request(gkid, current_gkid, root_key_specified)
+
+        root_key_object, root_key_id = self.get_root_key_object(
+            samdb, root_key_id if root_key_specified else root_key_id_hint, gkid
+        )
+
+        if root_key_specified:
+            if gkid.l0_idx < current_gkid.l0_idx:
+                # All of the seed keys with an L0 index less than the current L0
+                # index are from the past and thus are safe to return. If the
+                # caller has requested a specific seed key with a past L0 index,
+                # return the L1 seed key (L0, 31, −1), from which any L1 or L2
+                # seed key having that L0 index can be derived.
+                l1_gkid = Gkid(gkid.l0_idx, 31, -1)
+                seed_key = self.compute_seed_key(
+                    target_sd, root_key_id, root_key_object, l1_gkid
+                )
+                return SeedKeyPair(
+                    seed_key.key,
+                    None,
+                    Gkid(gkid.l0_idx, 31, 31),
+                    seed_key.hash_algorithm,
+                    root_key_id,
+                )
+
+            # All of the previous seed keys with an L0 index equal to the
+            # current L0 index can be derived from the current seed key or from
+            # the next older L1 seed key.
+            gkid = current_gkid
+
+        if gkid.l2_idx == 31:
+            # The current seed key, and all previous seed keys with that same L0
+            # index, can be derived from the L1 seed key (L0, L1, 31).
+            l1_gkid = Gkid(gkid.l0_idx, gkid.l1_idx, -1)
+            seed_key = self.compute_seed_key(
+                target_sd, root_key_id, root_key_object, l1_gkid
+            )
+            return SeedKeyPair(
+                seed_key.key, None, gkid, seed_key.hash_algorithm, root_key_id
+            )
+
+        # Compute the L2 seed key to return.
+        seed_key = self.compute_seed_key(target_sd, root_key_id, root_key_object, gkid)
+
+        next_older_seed_key = None
+        if gkid.l1_idx != 0:
+            # From the current seed key can be derived only those seed keys that
+            # share its L1 and L2 indices. To be able to derive previous seed
+            # keys with older L1 indices, the caller must be given the next
+            # older L1 seed key as well.
+            next_older_l1_gkid = Gkid(gkid.l0_idx, gkid.l1_idx - 1, -1)
+            next_older_seed_key = self.compute_seed_key(
+                target_sd, root_key_id, root_key_object, next_older_l1_gkid
+            ).key
+
+        return SeedKeyPair(
+            next_older_seed_key,
+            seed_key.key,
+            gkid,
+            seed_key.hash_algorithm,
+            root_key_id,
+        )
+
+    def get_key_exact(
+        self,
+        samdb: SamDB,
+        target_sd: bytes,  # An NDR‐encoded valid security descriptor in self‐relative format.
+        root_key_id: Optional[misc.GUID],
+        gkid: Gkid,
+        current_gkid: Optional[Gkid] = None,
+    ) -> GroupKey:
+        if current_gkid is None:
+            current_gkid = self.current_gkid()
+
+        root_key_specified = root_key_id is not None
+        self.validate_get_key_request(gkid, current_gkid, root_key_specified)
+
+        root_key_object, root_key_id = self.get_root_key_object(
+            samdb, root_key_id, gkid
+        )
+
+        return self.compute_seed_key(target_sd, root_key_id, root_key_object, gkid)
+
+    def get_root_key_data(self, root_key: RootKey) -> Tuple[bytes, Algorithm]:
+        version = root_key.get("msKds-Version", idx=0)
+        self.assertEqual(b"1", version)
+
+        algorithm_id = root_key.get("msKds-KDFAlgorithmID", idx=0)
+        self.assertEqual(b"SP800_108_CTR_HMAC", algorithm_id)
+
+        hash_algorithm = Algorithm.from_kdf_parameters(
+            root_key.get("msKds-KDFParam", idx=0)
+        )
+
+        root_key_data = root_key.get("msKds-RootKeyData", idx=0)
+        self.assertIsInstance(root_key_data, bytes)
+
+        return root_key_data, hash_algorithm
+
+    def compute_seed_key(
+        self,
+        target_sd: bytes,
+        root_key_id: misc.GUID,
+        root_key: RootKey,
+        target_gkid: Gkid,
+    ) -> GroupKey:
+        target_gkid_type = target_gkid.gkid_type()
+        self.assertIn(
+            target_gkid_type,
+            (GkidType.L1_SEED_KEY, GkidType.L2_SEED_KEY),
+            f"unexpected attempt to compute {target_gkid_type.description()}",
+        )
+
+        root_key_data, algorithm = self.get_root_key_data(root_key)
+        root_key_id_bytes = ndr_pack(root_key_id)
+
+        hash_algorithm = algorithm.algorithm()
+
+        # Derive the L0 seed key.
+        gkid = Gkid.l0_seed_key(target_gkid.l0_idx)
+        key = self.derive_key(root_key_data, root_key_id_bytes, hash_algorithm, gkid)
+
+        # Derive the L1 seed key.
+
+        gkid = gkid.derive_l1_seed_key()
+        key = self.derive_key(
+            key, root_key_id_bytes, hash_algorithm, gkid, target_sd=target_sd
+        )
+
+        while gkid.l1_idx != target_gkid.l1_idx:
+            gkid = gkid.derive_l1_seed_key()
+            key = self.derive_key(key, root_key_id_bytes, hash_algorithm, gkid)
+
+        # Derive the L2 seed key.
+        while gkid != target_gkid:
+            gkid = gkid.derive_l2_seed_key()
+            key = self.derive_key(key, root_key_id_bytes, hash_algorithm, gkid)
+
+        return GroupKey(key, gkid, algorithm, root_key_id)
+
+    def derive_key(
+        self,
+        key: bytes,
+        root_key_id_bytes: bytes,
+        hash_algorithm: hashes.HashAlgorithm,
+        gkid: Gkid,
+        *,
+        target_sd: Optional[bytes] = None,
+    ) -> bytes:
+        def u32_bytes(n: int) -> bytes:
+            return (n & 0xFFFF_FFFF).to_bytes(length=4, byteorder="little")
+
+        context = (
+            root_key_id_bytes
+            + u32_bytes(gkid.l0_idx)
+            + u32_bytes(gkid.l1_idx)
+            + u32_bytes(gkid.l2_idx)
+        )
+        if target_sd is not None:
+            context += target_sd
+        return self.kdf(hash_algorithm, key, context)
+
+    def kdf(
+        self,
+        hash_algorithm: hashes.HashAlgorithm,
+        key: bytes,
+        context: bytes,
+        *,
+        label="KDS service",
+        len_in_bytes=KEY_LEN_BYTES,
+    ) -> bytes:
+        label = label.encode("utf-16-le") + b"\x00\x00"
+        kdf = KBKDFHMAC(
+            algorithm=hash_algorithm,
+            mode=Mode.CounterMode,
+            length=len_in_bytes,
+            rlen=4,
+            llen=4,
+            location=CounterLocation.BeforeFixed,
+            label=label,
+            context=context,
+            fixed=None,
+            backend=default_backend(),
+        )
+        return kdf.derive(key)
+
+    def get_config_dn(self, samdb: SamDB, dn: str) -> ldb.Dn:
+        config_dn = samdb.get_config_basedn()
+        config_dn.add_child(dn)
+        return config_dn
+
+    def get_server_config_dn(self, samdb: SamDB) -> ldb.Dn:
+        # [MS-GKDI] has “CN=Sid Key Service” for “CN=Group Key Distribution
+        # Service”, and “CN=SID Key Server Configuration” for “CN=Group Key
+        # Distribution Service Server Configuration”.
+        return self.get_config_dn(
+            samdb,
+            "CN=Group Key Distribution Service Server Configuration,"
+            "CN=Server Configuration,"
+            "CN=Group Key Distribution Service,"
+            "CN=Services",
+        )
+
+    def get_root_key_container_dn(self, samdb: SamDB) -> ldb.Dn:
+        # [MS-GKDI] has “CN=Sid Key Service” for “CN=Group Key Distribution Service”.
+        return self.get_config_dn(
+            samdb,
+            "CN=Master Root Keys,CN=Group Key Distribution Service,CN=Services",
+        )
+
+    def create_root_key(
+        self,
+        samdb: SamDB,
+        domain_dn: ldb.Dn,
+        *,
+        use_start_time: Optional[Union[datetime.datetime, NtTime]] = None,
+        hash_algorithm: Optional[Algorithm] = Algorithm.SHA512,
+        guid: Optional[misc.GUID] = None,
+        data: Optional[bytes] = None,
+    ) -> misc.GUID:
+        # [MS-GKDI] 3.1.4.1.1, “Creating a New Root Key”, states that if the
+        # server receives a GetKey request and the root keys container in Active
+        # Directory is empty, the the server must create a new root key object
+        # based on the default Server Configuration object. Additional root keys
+        # are to be created based on either the default Server Configuration
+        # object or an updated one specifying optional configuration values.
+
+        guid_specified = guid is not None
+        if not guid_specified:
+            guid = misc.GUID(secrets.token_bytes(16))
+
+        if data is None:
+            data = secrets.token_bytes(KEY_LEN_BYTES)
+        else:
+            self.assertEqual(
+                KEY_LEN_BYTES,
+                len(data),
+                f"root key data must be {KEY_LEN_BYTES} bytes",
+            )
+
+        create_time = current_nt_time = self.current_nt_time()
+
+        if use_start_time is None:
+            # Root keys created by Windows without the ‘-EffectiveImmediately’
+            # parameter have an effective time of exactly ten days in the
+            # future, presumably to allow time for replication.
+            #
+            # Microsoft’s documentation on creating a KDS root key, located at
+            # https://learn.microsoft.com/en-us/windows-server/security/group-managed-service-accounts/create-the-key-distribution-services-kds-root-key,
+            # claims to the contrary that domain controllers will only wait up
+            # to ten hours before allowing Group Managed Service Accounts to be
+            # created.
+            #
+            # The same page includes instructions for creating a root key with
+            # an effective time of ten hours in the past (for testing purposes),
+            # but I’m not sure why — the KDS will consider a key valid for use
+            # immediately after its start time has passed, without bothering to
+            # wait ten hours first. In fact, it will consider a key to be valid
+            # a full ten hours (plus clock skew) *before* its declared start
+            # time — intentional, or (conceivably) the result of an accidental
+            # negation?
+            current_interval_start_nt_time = Gkid.from_nt_time(
+                current_nt_time
+            ).start_nt_time()
+            use_start_time = NtTime(
+                current_interval_start_nt_time + KEY_CYCLE_DURATION + MAX_CLOCK_SKEW
+            )
+
+        if isinstance(use_start_time, datetime.datetime):
+            use_start_nt_time = nt_time_from_datetime(use_start_time)
+        else:
+            self.assertIsInstance(use_start_time, int)
+            use_start_nt_time = use_start_time
+
+        kdf_parameters = None
+        if hash_algorithm is not None:
+            kdf_parameters = gkdi.KdfParameters()
+            kdf_parameters.hash_algorithm = hash_algorithm.value
+            kdf_parameters = ndr_pack(kdf_parameters)
+
+        # These are the encoded p and g values, respectively, of the “2048‐bit
+        # MODP Group with 256‐bit Prime Order Subgroup” from RFC 5114 section
+        # 2.3.
+        field_order = (
+            b"\x87\xa8\xe6\x1d\xb4\xb6f<\xff\xbb\xd1\x9ce\x19Y\x99\x8c\xee\xf6\x08"
+            b"f\r\xd0\xf2],\xee\xd4C^;\x00\xe0\r\xf8\xf1\xd6\x19W\xd4\xfa\xf7\xdfE"
+            b"a\xb2\xaa0\x16\xc3\xd9\x114\to\xaa;\xf4)m\x83\x0e\x9a|"
+            b" \x9e\x0cd\x97Qz\xbd"
+            b'Z\x8a\x9d0k\xcfg\xed\x91\xf9\xe6r[GX\xc0"\xe0\xb1\xefBu\xbf{l[\xfc\x11'
+            b"\xd4_\x90\x88\xb9A\xf5N\xb1\xe5\x9b\xb8\xbc9\xa0\xbf\x120\x7f\\O\xdbp\xc5"
+            b"\x81\xb2?v\xb6:\xca\xe1\xca\xa6\xb7\x90-RRg5H\x8a\x0e\xf1<m\x9aQ\xbf\xa4\xab"
+            b":\xd84w\x96RM\x8e\xf6\xa1g\xb5\xa4\x18%\xd9g\xe1D\xe5\x14\x05d%"
+            b"\x1c\xca\xcb\x83\xe6\xb4\x86\xf6\xb3\xca?yqP`&\xc0\xb8W\xf6\x89\x96(V"
+            b"\xde\xd4\x01\n\xbd\x0b\xe6!\xc3\xa3\x96\nT\xe7\x10\xc3u\xf2cu\xd7\x01A\x03"
+            b"\xa4\xb5C0\xc1\x98\xaf\x12a\x16\xd2'n\x11q_i8w\xfa\xd7\xef\t\xca\xdb\tJ\xe9"
+            b"\x1e\x1a\x15\x97"
+        )
+        generator = (
+            b"?\xb3,\x9bs\x13M\x0b.wPf`\xed\xbdHL\xa7\xb1\x8f!\xef T\x07\xf4y:"
+            b"\x1a\x0b\xa1%\x10\xdb\xc1Pw\xbeF?\xffO\xedJ\xac\x0b\xb5U\xbe:l\x1b\x0ckG\xb1"
+            b"\xbc7s\xbf~\x8cob\x90\x12(\xf8\xc2\x8c\xbb\x18\xa5Z\xe3\x13A\x00\ne"
+            b"\x01\x96\xf91\xc7zW\xf2\xdd\xf4c\xe5\xe9\xec\x14Kw}\xe6*\xaa\xb8\xa8b"
+            b"\x8a\xc3v\xd2\x82\xd6\xed8d\xe6y\x82B\x8e\xbc\x83\x1d\x144\x8fo/\x91\x93"
+            b"\xb5\x04Z\xf2vqd\xe1\xdf\xc9g\xc1\xfb?.U\xa4\xbd\x1b\xff\xe8;\x9c\x80"
+            b"\xd0R\xb9\x85\xd1\x82\xea\n\xdb*;s\x13\xd3\xfe\x14\xc8HK\x1e\x05%\x88\xb9"
+            b"\xb7\xd2\xbb\xd2\xdf\x01a\x99\xec\xd0n\x15W\xcd\t\x15\xb35;\xbbd\xe0\xec7"
+            b"\x7f\xd0(7\r\xf9+R\xc7\x89\x14(\xcd\xc6~\xb6\x18KR=\x1d\xb2F\xc3/c\x07\x84"
+            b"\x90\xf0\x0e\xf8\xd6G\xd1H\xd4yTQ^#'\xcf\xef\x98\xc5\x82fKL\x0fl\xc4\x16Y"
+        )
+        self.assertEqual(len(field_order), len(generator))
+        key_length = len(field_order)
+
+        ffc_dh_parameters = gkdi.FfcDhParameters()
+        ffc_dh_parameters.field_order = list(field_order)
+        ffc_dh_parameters.generator = list(generator)
+        ffc_dh_parameters.key_length = key_length
+        ffc_dh_parameters = ndr_pack(ffc_dh_parameters)
+
+        root_key_dn = self.get_root_key_container_dn(samdb)
+        root_key_dn.add_child(f"CN={guid}")
+
+        # Avoid deleting root key objects without subsequently restarting the
+        # Microsoft Key Distribution Service. This service will keep its root
+        # key cached even after the corresponding AD object has been deleted,
+        # breaking later tests that try to look up the root key object.
+
+        details = {
+            "dn": root_key_dn,
+            "objectClass": "msKds-ProvRootKey",
+            "msKds-RootKeyData": data,
+            "msKds-CreateTime": str(create_time),
+            "msKds-UseStartTime": str(use_start_nt_time),
+            "msKds-DomainID": str(domain_dn),
+            "msKds-Version": "1",  # comes from Server Configuration object.
+            "msKds-KDFAlgorithmID": (
+                "SP800_108_CTR_HMAC"
+            ),  # comes from Server Configuration.
+            "msKds-SecretAgreementAlgorithmID": (
+                "DH"
+            ),  # comes from Server Configuration.
+            "msKds-SecretAgreementParam": (
+                ffc_dh_parameters
+            ),  # comes from Server Configuration.
+            "msKds-PublicKeyLength": "2048",  # comes from Server Configuration.
+            "msKds-PrivateKeyLength": (
+                "512"
+            ),  # comes from Server Configuration. [MS-GKDI] claims this defaults to ‘256’.
+        }
+        if kdf_parameters is not None:
+            details["msKds-KDFParam"] = (
+                kdf_parameters  # comes from Server Configuration.
+            )
+
+        if guid_specified:
+            # A test may request that a root key have a specific GUID so that
+            # results may be reproducible. Ensure these keys are cleaned up
+            # afterwards.
+            self.addCleanup(delete_force, samdb, root_key_dn)
+        samdb.add(details)
+
+        return guid
--- a/python/samba/tests/krb5/gkdi_tests.py
+++ b/python/samba/tests/krb5/gkdi_tests.py
@ -0,0 +1,716 @@
+#!/usr/bin/env python3
+# Unix SMB/CIFS implementation.
+# Copyright (C) Catalyst.Net Ltd 2023
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+
+import sys
+import os
+
+sys.path.insert(0, "bin/python")
+os.environ["PYTHONUNBUFFERED"] = "1"
+
+import secrets
+
+from typing import ClassVar, Optional
+
+from samba import HRES_E_INVALIDARG, HRES_NTE_BAD_KEY, HRES_NTE_NO_KEY
+from samba.dcerpc import gkdi, misc
+from samba.gkdi import (
+    Algorithm,
+    Gkid,
+    KEY_CYCLE_DURATION,
+    MAX_CLOCK_SKEW,
+    NtTime,
+    NtTimeDelta,
+    SeedKeyPair,
+)
+from samba.nt_time import timedelta_from_nt_time_delta
+
+from samba.tests.gkdi import GetKeyError, GkdiBaseTest, ROOT_KEY_START_TIME
+from samba.tests.krb5.kdc_base_test import KDCBaseTest
+
+
+class GkdiKdcBaseTest(GkdiBaseTest, KDCBaseTest):
+    _root_key: ClassVar[misc.GUID]
+
+    @classmethod
+    def setUpClass(cls) -> None:
+        super().setUpClass()
+
+        cls._root_key = None
+
+    def setUp(self) -> None:
+        super().setUp()
+
+        if self._root_key is None:
+            # GKDI requires a root key to operate. Creating a root key here
+            # saves creating one before every test.
+            #
+            # We cannot delete this key after the tests have run, as Windows
+            # might have decided to cache it to be used in subsequent runs. It
+            # will keep a root key cached even if the corresponding AD object
+            # has been deleted, leading to various problems later.
+            cls = type(self)
+            cls._root_key = self.new_root_key(use_start_time=ROOT_KEY_START_TIME)
+
+    def new_root_key(self, *args, **kwargs) -> misc.GUID:
+        samdb = self.get_samdb()
+        domain_dn = self.get_server_dn(samdb)
+        return self.create_root_key(samdb, domain_dn, *args, **kwargs)
+
+    def gkdi_conn(self) -> gkdi.gkdi:
+        # The seed keys used by Group Managed Service Accounts correspond to the
+        # Enterprise DCs SID (S-1-5-9); as such they can be retrieved only by
+        # server accounts.
+        return self.gkdi_connect(
+            self.dc_host,
+            self.get_lp(),
+            self.get_cached_creds(account_type=self.AccountType.SERVER),
+        )
+
+    def check_rpc_get_key(
+        self, root_key_id: Optional[misc.GUID], gkid: Gkid
+    ) -> SeedKeyPair:
+        got_key_pair = self.rpc_get_key(
+            self.gkdi_conn(), self.gmsa_sd, root_key_id, gkid
+        )
+        expected_key_pair = self.get_key(
+            self.get_samdb(),
+            self.gmsa_sd,
+            root_key_id,
+            gkid,
+            root_key_id_hint=got_key_pair.root_key_id if root_key_id is None else None,
+        )
+        self.assertEqual(
+            got_key_pair.root_key_id,
+            expected_key_pair.root_key_id,
+            "root key IDs must match",
+        )
+        self.assertEqual(got_key_pair, expected_key_pair, "key pairs must match")
+
+        return got_key_pair
+
+
+class GkdiExplicitRootKeyTests(GkdiKdcBaseTest):
+    def test_current_l0_idx(self):
+        """Request a key with the current L0 index. This index is regularly
+        incremented every 427 days or so."""
+        root_key_id = self.new_root_key()
+
+        # It actually doesn’t matter what we specify for the L1 and L2 indices.
+        # We’ll get the same result regardless — they just cannot specify a key
+        # from the future.
+        self.check_rpc_get_key(root_key_id, self.current_gkid())
+
+    def test_previous_l0_idx(self):
+        """Request a key with a previous L0 index."""
+        root_key_id = self.new_root_key(use_start_time=ROOT_KEY_START_TIME)
+
+        # It actually doesn’t matter what we specify for the L1 and L2 indices.
+        # We’ll get the same result regardless.
+        previous_l0_idx = self.current_gkid().l0_idx - 1
+        key = self.check_rpc_get_key(root_key_id, Gkid(previous_l0_idx, 0, 0))
+
+        # Expect to get an L1 seed key.
+        self.assertIsNotNone(key.l1_key)
+        self.assertIsNone(key.l2_key)
+        self.assertEqual(Gkid(previous_l0_idx, 31, 31), key.gkid)
+        self.assertEqual(root_key_id, key.root_key_id)
+
+    def test_algorithm_sha1(self):
+        """Test with the SHA1 algorithm."""
+        key = self.check_rpc_get_key(
+            self.new_root_key(hash_algorithm=Algorithm.SHA1),
+            self.current_gkid(),
+        )
+        self.assertIs(Algorithm.SHA1, key.hash_algorithm)
+
+    def test_algorithm_sha256(self):
+        """Test with the SHA256 algorithm."""
+        key = self.check_rpc_get_key(
+            self.new_root_key(hash_algorithm=Algorithm.SHA256),
+            self.current_gkid(),
+        )
+        self.assertIs(Algorithm.SHA256, key.hash_algorithm)
+
+    def test_algorithm_sha384(self):
+        """Test with the SHA384 algorithm."""
+        key = self.check_rpc_get_key(
+            self.new_root_key(hash_algorithm=Algorithm.SHA384),
+            self.current_gkid(),
+        )
+        self.assertIs(Algorithm.SHA384, key.hash_algorithm)
+
+    def test_algorithm_sha512(self):
+        """Test with the SHA512 algorithm."""
+        key = self.check_rpc_get_key(
+            self.new_root_key(hash_algorithm=Algorithm.SHA512),
+            self.current_gkid(),
+        )
+        self.assertIs(Algorithm.SHA512, key.hash_algorithm)
+
+    def test_algorithm_none(self):
+        """Test without a specified algorithm."""
+        key = self.check_rpc_get_key(
+            self.new_root_key(hash_algorithm=None),
+            self.current_gkid(),
+        )
+        self.assertIs(Algorithm.SHA256, key.hash_algorithm)
+
+    def test_future_key(self):
+        """Try to request a key from the future."""
+        root_key_id = self.new_root_key(use_start_time=ROOT_KEY_START_TIME)
+
+        future_gkid = self.current_gkid(
+            offset=timedelta_from_nt_time_delta(
+                NtTimeDelta(KEY_CYCLE_DURATION + MAX_CLOCK_SKEW)
+            )
+        )
+
+        with self.assertRaises(GetKeyError) as err:
+            self.get_key(self.get_samdb(), self.gmsa_sd, root_key_id, future_gkid)
+
+        self.assertEqual(
+            HRES_E_INVALIDARG,
+            err.exception.args[0],
+            "requesting a key from the future should fail with INVALID_PARAMETER",
+        )
+
+        with self.assertRaises(GetKeyError) as rpc_err:
+            self.rpc_get_key(self.gkdi_conn(), self.gmsa_sd, root_key_id, future_gkid)
+
+        self.assertEqual(
+            HRES_E_INVALIDARG,
+            rpc_err.exception.args[0],
+            "requesting a key from the future should fail with INVALID_PARAMETER",
+        )
+
+    def test_root_key_use_start_time_zero(self):
+        """Attempt to use a root key with an effective time of zero."""
+        root_key_id = self.new_root_key(use_start_time=NtTime(0))
+
+        gkid = self.current_gkid()
+
+        with self.assertRaises(GetKeyError) as err:
+            self.get_key(self.get_samdb(), self.gmsa_sd, root_key_id, gkid)
+
+        self.assertEqual(
+            HRES_NTE_BAD_KEY,
+            err.exception.args[0],
+            "using a root key with an effective time of zero should fail with BAD_KEY",
+        )
+
+        with self.assertRaises(GetKeyError) as rpc_err:
+            self.rpc_get_key(self.gkdi_conn(), self.gmsa_sd, root_key_id, gkid)
+
+        self.assertEqual(
+            HRES_NTE_BAD_KEY,
+            rpc_err.exception.args[0],
+            "using a root key with an effective time of zero should fail with BAD_KEY",
+        )
+
+    def test_root_key_use_start_time_too_low(self):
+        """Attempt to use a root key with an effective time set too low."""
+        root_key_id = self.new_root_key(use_start_time=NtTime(ROOT_KEY_START_TIME - 1))
+
+        gkid = self.current_gkid()
+
+        with self.assertRaises(GetKeyError) as err:
+            self.get_key(self.get_samdb(), self.gmsa_sd, root_key_id, gkid)
+
+        self.assertEqual(
+            HRES_E_INVALIDARG,
+            err.exception.args[0],
+            "using a root key with too low effective time should fail with"
+            " INVALID_PARAMETER",
+        )
+
+        with self.assertRaises(GetKeyError) as rpc_err:
+            self.rpc_get_key(self.gkdi_conn(), self.gmsa_sd, root_key_id, gkid)
+
+        self.assertEqual(
+            HRES_E_INVALIDARG,
+            rpc_err.exception.args[0],
+            "using a root key with too low effective time should fail with"
+            " INVALID_PARAMETER",
+        )
+
+    def test_before_valid(self):
+        """Attempt to use a key before it is valid."""
+        gkid = self.current_gkid()
+        valid_start_time = NtTime(
+            gkid.start_nt_time() + KEY_CYCLE_DURATION + MAX_CLOCK_SKEW
+        )
+
+        # Using a valid root key is allowed.
+        valid_root_key_id = self.new_root_key(use_start_time=valid_start_time)
+        self.check_rpc_get_key(valid_root_key_id, gkid)
+
+        # But attempting to use a root key that is not yet valid will result in
+        # an INVALID_PARAMETER error.
+        invalid_root_key_id = self.new_root_key(use_start_time=valid_start_time + 1)
+
+        with self.assertRaises(GetKeyError) as err:
+            self.get_key(self.get_samdb(), self.gmsa_sd, invalid_root_key_id, gkid)
+
+        self.assertEqual(
+            HRES_E_INVALIDARG,
+            err.exception.args[0],
+            "using a key before it is valid should fail with INVALID_PARAMETER",
+        )
+
+        with self.assertRaises(GetKeyError) as rpc_err:
+            self.rpc_get_key(self.gkdi_conn(), self.gmsa_sd, invalid_root_key_id, gkid)
+
+        self.assertEqual(
+            HRES_E_INVALIDARG,
+            rpc_err.exception.args[0],
+            "using a key before it is valid should fail with INVALID_PARAMETER",
+        )
+
+    def test_non_existent_root_key(self):
+        """Attempt to use a non‐existent root key."""
+        root_key_id = misc.GUID(secrets.token_bytes(16))
+
+        gkid = self.current_gkid()
+
+        with self.assertRaises(GetKeyError) as err:
+            self.get_key(self.get_samdb(), self.gmsa_sd, root_key_id, gkid)
+
+        self.assertEqual(
+            HRES_NTE_NO_KEY,
+            err.exception.args[0],
+            "using a non‐existent root key should fail with NO_KEY",
+        )
+
+        with self.assertRaises(GetKeyError) as rpc_err:
+            self.rpc_get_key(self.gkdi_conn(), self.gmsa_sd, root_key_id, gkid)
+
+        self.assertEqual(
+            HRES_NTE_NO_KEY,
+            rpc_err.exception.args[0],
+            "using a non‐existent root key should fail with NO_KEY",
+        )
+
+
+class GkdiImplicitRootKeyTests(GkdiKdcBaseTest):
+    def test_l1_seed_key(self):
+        """Request a key and expect to receive an L1 seed key."""
+        gkid = Gkid(300, 0, 31)
+        key = self.check_rpc_get_key(None, gkid)
+
+        # Expect to get an L1 seed key.
+        self.assertIsNotNone(key.l1_key)
+        self.assertIsNone(key.l2_key)
+        self.assertEqual(gkid, key.gkid)
+
+    def test_l2_seed_key(self):
+        """Request a key and expect to receive an L2 seed key."""
+        gkid = Gkid(300, 0, 0)
+        key = self.check_rpc_get_key(None, gkid)
+
+        # Expect to get an L2 seed key.
+        self.assertIsNone(key.l1_key)
+        self.assertIsNotNone(key.l2_key)
+        self.assertEqual(gkid, key.gkid)
+
+    def test_both_seed_keys(self):
+        """Request a key and expect to receive L1 and L2 seed keys."""
+        gkid = Gkid(300, 1, 0)
+        key = self.check_rpc_get_key(None, gkid)
+
+        # Expect to get both L1 and L2 seed keys.
+        self.assertIsNotNone(key.l1_key)
+        self.assertIsNotNone(key.l2_key)
+        self.assertEqual(gkid, key.gkid)
+
+    def test_both_seed_keys_no_hint(self):
+        """Request a key, but don’t specify ‘root_key_id_hint’."""
+        gkid = Gkid(300, 1, 0)
+        key = self.get_key(
+            self.get_samdb(),
+            self.gmsa_sd,
+            None,
+            gkid,
+        )
+
+        # Expect to get both L1 and L2 seed keys.
+        self.assertIsNotNone(key.l1_key)
+        self.assertIsNotNone(key.l2_key)
+        self.assertEqual(gkid, key.gkid)
+
+    def test_request_l0_seed_key(self):
+        """Attempt to request an L0 seed key."""
+        gkid = Gkid.l0_seed_key(300)
+
+        with self.assertRaises(GetKeyError) as err:
+            self.get_key(self.get_samdb(), self.gmsa_sd, None, gkid)
+
+        self.assertEqual(
+            HRES_E_INVALIDARG,
+            err.exception.args[0],
+            "requesting an L0 seed key should fail with INVALID_PARAMETER",
+        )
+
+        with self.assertRaises(GetKeyError) as rpc_err:
+            self.rpc_get_key(self.gkdi_conn(), self.gmsa_sd, None, gkid)
+
+        self.assertEqual(
+            HRES_E_INVALIDARG,
+            rpc_err.exception.args[0],
+            "requesting an L0 seed key should fail with INVALID_PARAMETER",
+        )
+
+    def test_request_l1_seed_key(self):
+        """Attempt to request an L1 seed key."""
+        gkid = Gkid.l1_seed_key(300, 0)
+
+        with self.assertRaises(GetKeyError) as err:
+            self.get_key(self.get_samdb(), self.gmsa_sd, None, gkid)
+
+        self.assertEqual(
+            HRES_E_INVALIDARG,
+            err.exception.args[0],
+            "requesting an L1 seed key should fail with INVALID_PARAMETER",
+        )
+
+        with self.assertRaises(GetKeyError) as rpc_err:
+            self.rpc_get_key(self.gkdi_conn(), self.gmsa_sd, None, gkid)
+
+        self.assertEqual(
+            HRES_E_INVALIDARG,
+            rpc_err.exception.args[0],
+            "requesting an L1 seed key should fail with INVALID_PARAMETER",
+        )
+
+    def test_request_default_seed_key(self):
+        """Try to make a request with the default GKID."""
+        gkid = Gkid.default()
+
+        self.assertRaises(
+            NotImplementedError,
+            self.get_key,
+            self.get_samdb(),
+            self.gmsa_sd,
+            None,
+            gkid,
+        )
+
+        self.rpc_get_key(self.gkdi_conn(), self.gmsa_sd, None, gkid)
+
+
+class GkdiSelfTests(GkdiKdcBaseTest):
+    def test_current_l0_idx_l1_seed_key(self):
+        """Request a key with the current L0 index, expecting to receive an L1
+        seed key."""
+        root_key_id = self.new_root_key(
+            use_start_time=ROOT_KEY_START_TIME,
+            hash_algorithm=Algorithm.SHA512,
+            guid=misc.GUID("89f70521-9d66-441f-c314-1b462f9b1052"),
+            data=bytes.fromhex(
+                "a6ef87dbbbf86b6bbe55750b941f13ca99efe5185e2e2bded5b838d8a0e77647"
+                "0537e68cae45a7a0f4b1d6c9bf5494c3f879e172e326557cdbb6a56e8799a722"
+            ),
+        )
+
+        current_gkid = Gkid(255, 24, 31)
+        key = self.get_key(
+            self.get_samdb(),
+            self.gmsa_sd,
+            root_key_id,
+            Gkid(255, 2, 5),
+            current_gkid=current_gkid,
+        )
+
+        # Expect to get an L1 seed key.
+        self.assertEqual(current_gkid, key.gkid)
+        self.assertEqual(root_key_id, key.root_key_id)
+        self.assertEqual(Algorithm.SHA512, key.hash_algorithm)
+        self.assertEqual(
+            bytes.fromhex(
+                "bd538a073490f3cf9451c933025de9b22c97eaddaffa94b379e2b919a4bed147"
+                "5bc67f6a9175b139c69204c57d4300a0141ffe34d12ced84614593b1aa13af1c"
+            ),
+            key.l1_key,
+        )
+        self.assertIsNone(key.l2_key)
+
+    def test_current_l0_idx_l2_seed_key(self):
+        """Request a key with the current L0 index, expecting to receive an L2
+        seed key."""
+        root_key_id = self.new_root_key(
+            use_start_time=ROOT_KEY_START_TIME,
+            hash_algorithm=Algorithm.SHA512,
+            guid=misc.GUID("1a3d6c30-aa81-cb7f-d3fe-80775d135dfe"),
+            data=bytes.fromhex(
+                "dfd95be3153a0805c65694e7d284aace5ab0aa493350025eb8dbc6df0b4e9256"
+                "fb4cbfbe6237ce3732694e2608760076b67082d39abd3c0fedba1b8873645064"
+            ),
+        )
+
+        current_gkid = Gkid(321, 0, 12)
+        key = self.get_key(
+            self.get_samdb(),
+            self.gmsa_sd,
+            root_key_id,
+            Gkid(321, 0, 1),
+            current_gkid=current_gkid,
+        )
+
+        # Expect to get an L2 seed key.
+        self.assertEqual(current_gkid, key.gkid)
+        self.assertEqual(root_key_id, key.root_key_id)
+        self.assertEqual(Algorithm.SHA512, key.hash_algorithm)
+        self.assertIsNone(key.l1_key)
+        self.assertEqual(
+            bytes.fromhex(
+                "bbbd9376cd16c247ed40f5912d1908218c08f0915bae02fe02cbfb3753bde406"
+                "f9c553acd95143cf63906a0440e3cf237d2335ae4e4b9cd2d946a71351ebcb7b"
+            ),
+            key.l2_key,
+        )
+
+    def test_current_l0_idx_both_seed_keys(self):
+        """Request a key with the current L0 index, expecting to receive L1 and
+        L2 seed keys."""
+        root_key_id = self.new_root_key(
+            use_start_time=ROOT_KEY_START_TIME,
+            hash_algorithm=Algorithm.SHA512,
+            guid=misc.GUID("09de0b38-c743-7abf-44ea-7a3c3e404314"),
+            data=bytes.fromhex(
+                "d5912d0eb3bd60e1371b1e525dd83be7fc5baf77018b0dba6bd948b7a98ebe5a"
+                "f37674332506a46c52c108a62f2a3e89251ad1bde6d539004679c0658853bb68"
+            ),
+        )
+
+        current_gkid = Gkid(123, 21, 0)
+        key = self.get_key(
+            self.get_samdb(),
+            self.gmsa_sd,
+            root_key_id,
+            Gkid(123, 2, 1),
+            current_gkid=current_gkid,
+        )
+
+        # Expect to get both L1 and L2 seed keys.
+        self.assertEqual(current_gkid, key.gkid)
+        self.assertEqual(root_key_id, key.root_key_id)
+        self.assertEqual(Algorithm.SHA512, key.hash_algorithm)
+        self.assertEqual(
+            bytes.fromhex(
+                "b1f7c5896e7dc791d9c0aaf8ca7dbab8c172a4f8b873db488a3c4cbd0f559b11"
+                "52ffba39d4aff2d9e8aada90b27a3c94a5af996f4b8f584a4f37ccab4d505d3d"
+            ),
+            key.l1_key,
+        )
+        self.assertEqual(
+            bytes.fromhex(
+                "133c9bbd20d9227aeb38dfcd3be6bcbfc5983ba37202088ff5c8a70511214506"
+                "a69c195a8807cd844bcb955e9569c8e4d197759f28577cc126d15f16a7da4ee0"
+            ),
+            key.l2_key,
+        )
+
+    def test_previous_l0_idx(self):
+        """Request a key with a previous L0 index."""
+        root_key_id = self.new_root_key(
+            use_start_time=ROOT_KEY_START_TIME,
+            hash_algorithm=Algorithm.SHA512,
+            guid=misc.GUID("27136e8f-e093-6fe3-e57f-1d915b102e1c"),
+            data=bytes.fromhex(
+                "b41118c60a19cafa5ecf858d1a2a2216527b2daedf386e9d599e42a46add6c7d"
+                "c93868619761c880ff3674a77c6e5fbf3434d130a9727bb2cd2a2557bdcfc752"
+            ),
+        )
+
+        key = self.get_key(
+            self.get_samdb(),
+            self.gmsa_sd,
+            root_key_id,
+            Gkid(100, 20, 30),
+            current_gkid=Gkid(101, 2, 3),
+        )
+
+        # Expect to get an L1 seed key.
+        self.assertEqual(Gkid(100, 31, 31), key.gkid)
+        self.assertEqual(root_key_id, key.root_key_id)
+        self.assertEqual(Algorithm.SHA512, key.hash_algorithm)
+        self.assertEqual(
+            bytes.fromhex(
+                "935cbdc06198eb28fa44b8d8278f51072c4613999236585041ede8e72d02fe95"
+                "e3454f046382cbc0a700779b79474dd7e080509d76302d2937407e96e3d3d022"
+            ),
+            key.l1_key,
+        )
+        self.assertIsNone(key.l2_key)
+
+    def test_sha1(self):
+        """Request a key derived with SHA1."""
+        root_key_id = self.new_root_key(
+            use_start_time=ROOT_KEY_START_TIME,
+            hash_algorithm=Algorithm.SHA1,
+            guid=misc.GUID("970abad6-fe55-073a-caf1-b801d3f26bd3"),
+            data=bytes.fromhex(
+                "3bed03bf0fb7d4013149154f24ca2d59b98db6d588cb1f54eca083855e25eb28"
+                "d3562a01adc78c4b70e0b72a59515863e7732b853fba02dd7646e63108441211"
+            ),
+        )
+
+        current_gkid = Gkid(1, 2, 3)
+        key = self.get_key(
+            self.get_samdb(),
+            self.gmsa_sd,
+            root_key_id,
+            Gkid(1, 1, 1),
+            current_gkid=current_gkid,
+        )
+
+        # Expect to get both L1 and L2 seed keys.
+        self.assertEqual(current_gkid, key.gkid)
+        self.assertEqual(root_key_id, key.root_key_id)
+        self.assertEqual(Algorithm.SHA1, key.hash_algorithm)
+        self.assertEqual(
+            bytes.fromhex(
+                "576cb68f2e52eb739f817b488c3590d86f1c2c365f3fc9201d9c7fee7494853d"
+                "58746ee13e48f18aa6fa69f7157de3d07de34e13836792b7c088ffb6914a89c2"
+            ),
+            key.l1_key,
+        )
+        self.assertEqual(
+            bytes.fromhex(
+                "3ffb825adaf116b6533207d568a30ed3d3f21c68840941c9456684f9afa11b05"
+                "6e0c59391b4d88c495d984c3d680029cc5c594630f34179119c1c5acaae5e90e"
+            ),
+            key.l2_key,
+        )
+
+    def test_sha256(self):
+        """Request a key derived with SHA256."""
+        root_key_id = self.new_root_key(
+            use_start_time=ROOT_KEY_START_TIME,
+            hash_algorithm=Algorithm.SHA256,
+            guid=misc.GUID("45e26207-ed33-dcd5-925a-518a0deef69e"),
+            data=bytes.fromhex(
+                "28b5b6503d3c1d24814de781bb7bfce3ef69eed1ce4809372bee2c506270c5f0"
+                "b5c6df597472623f256c86daa0991e8a11a1705f21b2cfdc0bb9db4ba23246a2"
+            ),
+        )
+
+        current_gkid = Gkid(222, 22, 22)
+        key = self.get_key(
+            self.get_samdb(),
+            self.gmsa_sd,
+            root_key_id,
+            Gkid(222, 11, 0),
+            current_gkid=current_gkid,
+        )
+
+        # Expect to get both L1 and L2 seed keys.
+        self.assertEqual(current_gkid, key.gkid)
+        self.assertEqual(root_key_id, key.root_key_id)
+        self.assertEqual(Algorithm.SHA256, key.hash_algorithm)
+        self.assertEqual(
+            bytes.fromhex(
+                "57aced6e75f83f3af4f879b38b60f090b42e4bfa022fae3e6fd94280b469b0ec"
+                "15d8b853a870b5fbdf28708cce19273b74a573acbe0deda8ef515db4691e2dcb"
+            ),
+            key.l1_key,
+        )
+        self.assertEqual(
+            bytes.fromhex(
+                "752a0879ae2424c0504c7493599f13e588e1bbdc252f83325ad5b1fb91c24c89"
+                "01d440f3ff9ffba59fcd65bb975732d9f383dd50b898174bb9393e383d25d540"
+            ),
+            key.l2_key,
+        )
+
+    def test_sha384(self):
+        """Request a key derived with SHA384."""
+        root_key_id = self.new_root_key(
+            use_start_time=ROOT_KEY_START_TIME,
+            hash_algorithm=Algorithm.SHA384,
+            guid=misc.GUID("66e6d9f7-4924-f3fc-fe34-605634d42ebd"),
+            data=bytes.fromhex(
+                "23e5ba86cbd88f7b432ee66dbb03bf4eebf401cbfc3df735d4d728b503c87f84"
+                "3207c6f6153f190dfe85a86cb8d8b74df13b25305981be8d7e29c96ee54c9630"
+            ),
+        )
+
+        current_gkid = Gkid(287, 28, 27)
+        key = self.get_key(
+            self.get_samdb(),
+            self.gmsa_sd,
+            root_key_id,
+            Gkid(287, 8, 7),
+            current_gkid=current_gkid,
+        )
+
+        # Expect to get both L1 and L2 seed keys.
+        self.assertEqual(current_gkid, key.gkid)
+        self.assertEqual(root_key_id, key.root_key_id)
+        self.assertEqual(Algorithm.SHA384, key.hash_algorithm)
+        self.assertEqual(
+            bytes.fromhex(
+                "fabadd7a9a63df57d6832df7a735aebb6e181888b2eaf301a2e4ff9a70246d38"
+                "ab1d2416325bf3eb726a0267bab4bd950c7291f05ea5f17197ece56992af3eb8"
+            ),
+            key.l1_key,
+        )
+        self.assertEqual(
+            bytes.fromhex(
+                "ec1c65634b5694818e1d341da9996db8f2a1ef6a2c776a7126a7ebd18b37a073"
+                "afdac44c41b167b14e4b872d485bbb6d7b70964215d0e84a2ff142a9d943f205"
+            ),
+            key.l2_key,
+        )
+
+    def test_derive_key_exact(self):
+        """Derive a key at an exact GKID."""
+        root_key_id = self.new_root_key(
+            use_start_time=ROOT_KEY_START_TIME,
+            hash_algorithm=Algorithm.SHA512,
+            guid=misc.GUID("d95fb06f-5a9c-1829-e20d-27f3f2ecfbeb"),
+            data=bytes.fromhex(
+                "489f3531c537774d432d6b97e3bc1f43d2e8c6dc17eb0e4fd9a0870d2f1ebf92"
+                "e2496668a8b5bd11aea2d32d0aab716f48fe569f5c9b50ff3f9bf5deaea572fb"
+            ),
+        )
+
+        gkid = Gkid(333, 22, 11)
+        key = self.get_key_exact(
+            self.get_samdb(),
+            self.gmsa_sd,
+            root_key_id,
+            gkid,
+            current_gkid=self.current_gkid(),
+        )
+
+        self.assertEqual(gkid, key.gkid)
+        self.assertEqual(root_key_id, key.root_key_id)
+        self.assertEqual(Algorithm.SHA512, key.hash_algorithm)
+        self.assertEqual(
+            bytes.fromhex(
+                "d6ab3b14f4f4c8908aa3464011b39f10a8bfadb9974af90f7d9a9fede2fdc6e5"
+                "f68a628ec00f9994a3abd8a52ae9e2db4f68e83648311e9d7765f2535515b5e2"
+            ),
+            key.key,
+        )
+
+
+if __name__ == "__main__":
+    import unittest
+
+    unittest.main()
--- a/selftest/knownfail.d/gkdi
+++ b/selftest/knownfail.d/gkdi
@ -0,0 +1,18 @@
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_algorithm_none\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_algorithm_sha1\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_algorithm_sha256\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_algorithm_sha384\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_algorithm_sha512\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_before_valid\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_current_l0_idx\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_future_key\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_non_existent_root_key\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_previous_l0_idx\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_root_key_use_start_time_too_low\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiExplicitRootKeyTests\.test_root_key_use_start_time_zero\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiImplicitRootKeyTests\.test_both_seed_keys\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiImplicitRootKeyTests\.test_l1_seed_key\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiImplicitRootKeyTests\.test_l2_seed_key\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiImplicitRootKeyTests\.test_request_default_seed_key\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiImplicitRootKeyTests\.test_request_l0_seed_key\(ad_dc\)$
+^samba\.tests\.krb5\.gkdi_tests\.samba\.tests\.krb5\.gkdi_tests\.GkdiImplicitRootKeyTests\.test_request_l1_seed_key\(ad_dc\)$
--- a/source4/selftest/tests.py
+++ b/source4/selftest/tests.py
@ -2044,6 +2044,10 @@ planoldpythontestsuite(
    'ad_dc',
    'samba.tests.krb5.conditional_ace_tests',
    environ=krb5_environ)
+planoldpythontestsuite(
+    'ad_dc',
+    'samba.tests.krb5.gkdi_tests',
+    environ=krb5_environ)

 for env in [
        'vampire_dc',