source: trunk/server/source4/kdc/kdc.c@ 880

/*
   Unix SMB/CIFS implementation.

   KDC Server startup

   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2008
   Copyright (C) Andrew Tridgell        2005
   Copyright (C) Stefan Metzmacher      2005

   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 <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "smbd/process_model.h"
#include "lib/tsocket/tsocket.h"
#include "libcli/util/tstream.h"
#include "lib/messaging/irpc.h"
#include "librpc/gen_ndr/ndr_irpc.h"
#include "librpc/gen_ndr/ndr_krb5pac.h"
#include "lib/stream/packet.h"
#include "lib/socket/netif.h"
#include "param/param.h"
#include "kdc/kdc-glue.h"
#include "dsdb/samdb/samdb.h"
#include "auth/session.h"

extern struct krb5plugin_windc_ftable windc_plugin_table;
extern struct hdb_method hdb_samba4;

static NTSTATUS kdc_proxy_unavailable_error(struct kdc_server *kdc,
                                            TALLOC_CTX *mem_ctx,
                                            DATA_BLOB *out)
{
        int kret;
        krb5_data k5_error_blob;

        kret = krb5_mk_error(kdc->smb_krb5_context->krb5_context,
                             KRB5KDC_ERR_SVC_UNAVAILABLE, NULL, NULL,
                             NULL, NULL, NULL, NULL, &k5_error_blob);
        if (kret != 0) {
                DEBUG(2,(__location__ ": Unable to form krb5 error reply\n"));
                return NT_STATUS_INTERNAL_ERROR;
        }

        *out = data_blob_talloc(mem_ctx, k5_error_blob.data, k5_error_blob.length);
        krb5_data_free(&k5_error_blob);
        if (!out->data) {
                return NT_STATUS_NO_MEMORY;
        }

        return NT_STATUS_OK;
}

typedef enum kdc_process_ret (*kdc_process_fn_t)(struct kdc_server *kdc,
                                                 TALLOC_CTX *mem_ctx,
                                                 DATA_BLOB *input,
                                                 DATA_BLOB *reply,
                                                 struct tsocket_address *peer_addr,
                                                 struct tsocket_address *my_addr,
                                                 int datagram);

/* hold information about one kdc socket */
struct kdc_socket {
        struct kdc_server *kdc;
        struct tsocket_address *local_address;
        kdc_process_fn_t process;
};

struct kdc_tcp_call {
        struct kdc_tcp_connection *kdc_conn;
        DATA_BLOB in;
        DATA_BLOB out;
        uint8_t out_hdr[4];
        struct iovec out_iov[2];
};

/*
  state of an open tcp connection
*/
struct kdc_tcp_connection {
        /* stream connection we belong to */
        struct stream_connection *conn;

        /* the kdc_server the connection belongs to */
        struct kdc_socket *kdc_socket;

        struct tstream_context *tstream;

        struct tevent_queue *send_queue;
};


static void kdc_tcp_terminate_connection(struct kdc_tcp_connection *kdcconn, const char *reason)
{
        stream_terminate_connection(kdcconn->conn, reason);
}

static void kdc_tcp_recv(struct stream_connection *conn, uint16_t flags)
{
        struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private_data,
                                                             struct kdc_tcp_connection);
        /* this should never be triggered! */
        kdc_tcp_terminate_connection(kdcconn, "kdc_tcp_recv: called");
}

static void kdc_tcp_send(struct stream_connection *conn, uint16_t flags)
{
        struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private_data,
                                                             struct kdc_tcp_connection);
        /* this should never be triggered! */
        kdc_tcp_terminate_connection(kdcconn, "kdc_tcp_send: called");
}

/**
   Wrapper for krb5_kdc_process_krb5_request, converting to/from Samba
   calling conventions
*/

static enum kdc_process_ret kdc_process(struct kdc_server *kdc,
                                        TALLOC_CTX *mem_ctx,
                                        DATA_BLOB *input,
                                        DATA_BLOB *reply,
                                        struct tsocket_address *peer_addr,
                                        struct tsocket_address *my_addr,
                                        int datagram_reply)
{
        int ret;
        char *pa;
        struct sockaddr_storage ss;
        krb5_data k5_reply;
        krb5_data_zero(&k5_reply);

        krb5_kdc_update_time(NULL);

        ret = tsocket_address_bsd_sockaddr(peer_addr, (struct sockaddr *) &ss,
                                sizeof(struct sockaddr_storage));
        if (ret < 0) {
                return KDC_PROCESS_FAILED;
        }
        pa = tsocket_address_string(peer_addr, mem_ctx);
        if (pa == NULL) {
                return KDC_PROCESS_FAILED;
        }

        DEBUG(10,("Received KDC packet of length %lu from %s\n",
                                (long)input->length - 4, pa));

        ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context,
                                            kdc->config,
                                            input->data, input->length,
                                            &k5_reply,
                                            pa,
                                            (struct sockaddr *) &ss,
                                            datagram_reply);
        if (ret == -1) {
                *reply = data_blob(NULL, 0);
                return KDC_PROCESS_FAILED;
        }

        if (ret == HDB_ERR_NOT_FOUND_HERE) {
                *reply = data_blob(NULL, 0);
                return KDC_PROCESS_PROXY;
        }

        if (k5_reply.length) {
                *reply = data_blob_talloc(mem_ctx, k5_reply.data, k5_reply.length);
                krb5_data_free(&k5_reply);
        } else {
                *reply = data_blob(NULL, 0);
        }
        return KDC_PROCESS_OK;
}

static void kdc_tcp_call_proxy_done(struct tevent_req *subreq);
static void kdc_tcp_call_writev_done(struct tevent_req *subreq);

static void kdc_tcp_call_loop(struct tevent_req *subreq)
{
        struct kdc_tcp_connection *kdc_conn = tevent_req_callback_data(subreq,
                                      struct kdc_tcp_connection);
        struct kdc_tcp_call *call;
        NTSTATUS status;
        enum kdc_process_ret ret;

        call = talloc(kdc_conn, struct kdc_tcp_call);
        if (call == NULL) {
                kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_call_loop: "
                                "no memory for kdc_tcp_call");
                return;
        }
        call->kdc_conn = kdc_conn;

        status = tstream_read_pdu_blob_recv(subreq,
                                            call,
                                            &call->in);
        TALLOC_FREE(subreq);
        if (!NT_STATUS_IS_OK(status)) {
                const char *reason;

                reason = talloc_asprintf(call, "kdc_tcp_call_loop: "
                                         "tstream_read_pdu_blob_recv() - %s",
                                         nt_errstr(status));
                if (!reason) {
                        reason = nt_errstr(status);
                }

                kdc_tcp_terminate_connection(kdc_conn, reason);
                return;
        }

        DEBUG(10,("Received krb5 TCP packet of length %lu from %s\n",
                 (long) call->in.length,
                 tsocket_address_string(kdc_conn->conn->remote_address, call)));

        /* skip length header */
        call->in.data +=4;
        call->in.length -= 4;

        /* Call krb5 */
        ret = kdc_conn->kdc_socket->process(kdc_conn->kdc_socket->kdc,
                                           call,
                                           &call->in,
                                           &call->out,
                                           kdc_conn->conn->remote_address,
                                           kdc_conn->conn->local_address,
                                           0 /* Stream */);
        if (ret == KDC_PROCESS_FAILED) {
                kdc_tcp_terminate_connection(kdc_conn,
                                "kdc_tcp_call_loop: process function failed");
                return;
        }

        if (ret == KDC_PROCESS_PROXY) {
                uint16_t port;

                if (!kdc_conn->kdc_socket->kdc->am_rodc) {
                        kdc_tcp_terminate_connection(kdc_conn,
                                                     "kdc_tcp_call_loop: proxying requested when not RODC");
                        return;
                }
                port = tsocket_address_inet_port(kdc_conn->conn->local_address);

                subreq = kdc_tcp_proxy_send(call,
                                            kdc_conn->conn->event.ctx,
                                            kdc_conn->kdc_socket->kdc,
                                            port,
                                            call->in);
                if (subreq == NULL) {
                        kdc_tcp_terminate_connection(kdc_conn,
                                "kdc_tcp_call_loop: kdc_tcp_proxy_send failed");
                        return;
                }
                tevent_req_set_callback(subreq, kdc_tcp_call_proxy_done, call);
                return;
        }

        /* First add the length of the out buffer */
        RSIVAL(call->out_hdr, 0, call->out.length);
        call->out_iov[0].iov_base = (char *) call->out_hdr;
        call->out_iov[0].iov_len = 4;

        call->out_iov[1].iov_base = (char *) call->out.data;
        call->out_iov[1].iov_len = call->out.length;

        subreq = tstream_writev_queue_send(call,
                                           kdc_conn->conn->event.ctx,
                                           kdc_conn->tstream,
                                           kdc_conn->send_queue,
                                           call->out_iov, 2);
        if (subreq == NULL) {
                kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_call_loop: "
                                "no memory for tstream_writev_queue_send");
                return;
        }
        tevent_req_set_callback(subreq, kdc_tcp_call_writev_done, call);

        /*
         * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
         * packet_full_request_u32 provides the pdu length then.
         */
        subreq = tstream_read_pdu_blob_send(kdc_conn,
                                            kdc_conn->conn->event.ctx,
                                            kdc_conn->tstream,
                                            4, /* initial_read_size */
                                            packet_full_request_u32,
                                            kdc_conn);
        if (subreq == NULL) {
                kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_call_loop: "
                                "no memory for tstream_read_pdu_blob_send");
                return;
        }
        tevent_req_set_callback(subreq, kdc_tcp_call_loop, kdc_conn);
}

static void kdc_tcp_call_proxy_done(struct tevent_req *subreq)
{
        struct kdc_tcp_call *call = tevent_req_callback_data(subreq,
                        struct kdc_tcp_call);
        struct kdc_tcp_connection *kdc_conn = call->kdc_conn;
        NTSTATUS status;

        status = kdc_tcp_proxy_recv(subreq, call, &call->out);
        TALLOC_FREE(subreq);
        if (!NT_STATUS_IS_OK(status)) {
                /* generate an error packet */
                status = kdc_proxy_unavailable_error(kdc_conn->kdc_socket->kdc,
                                                     call, &call->out);
        }

        if (!NT_STATUS_IS_OK(status)) {
                const char *reason;

                reason = talloc_asprintf(call, "kdc_tcp_call_proxy_done: "
                                         "kdc_proxy_unavailable_error - %s",
                                         nt_errstr(status));
                if (!reason) {
                        reason = "kdc_tcp_call_proxy_done: kdc_proxy_unavailable_error() failed";
                }

                kdc_tcp_terminate_connection(call->kdc_conn, reason);
                return;
        }

        /* First add the length of the out buffer */
        RSIVAL(call->out_hdr, 0, call->out.length);
        call->out_iov[0].iov_base = (char *) call->out_hdr;
        call->out_iov[0].iov_len = 4;

        call->out_iov[1].iov_base = (char *) call->out.data;
        call->out_iov[1].iov_len = call->out.length;

        subreq = tstream_writev_queue_send(call,
                                           kdc_conn->conn->event.ctx,
                                           kdc_conn->tstream,
                                           kdc_conn->send_queue,
                                           call->out_iov, 2);
        if (subreq == NULL) {
                kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_call_loop: "
                                "no memory for tstream_writev_queue_send");
                return;
        }
        tevent_req_set_callback(subreq, kdc_tcp_call_writev_done, call);

        /*
         * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
         * packet_full_request_u32 provides the pdu length then.
         */
        subreq = tstream_read_pdu_blob_send(kdc_conn,
                                            kdc_conn->conn->event.ctx,
                                            kdc_conn->tstream,
                                            4, /* initial_read_size */
                                            packet_full_request_u32,
                                            kdc_conn);
        if (subreq == NULL) {
                kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_call_loop: "
                                "no memory for tstream_read_pdu_blob_send");
                return;
        }
        tevent_req_set_callback(subreq, kdc_tcp_call_loop, kdc_conn);
}

static void kdc_tcp_call_writev_done(struct tevent_req *subreq)
{
        struct kdc_tcp_call *call = tevent_req_callback_data(subreq,
                        struct kdc_tcp_call);
        int sys_errno;
        int rc;

        rc = tstream_writev_queue_recv(subreq, &sys_errno);
        TALLOC_FREE(subreq);
        if (rc == -1) {
                const char *reason;

                reason = talloc_asprintf(call, "kdc_tcp_call_writev_done: "
                                         "tstream_writev_queue_recv() - %d:%s",
                                         sys_errno, strerror(sys_errno));
                if (!reason) {
                        reason = "kdc_tcp_call_writev_done: tstream_writev_queue_recv() failed";
                }

                kdc_tcp_terminate_connection(call->kdc_conn, reason);
                return;
        }

        /* We don't care about errors */

        talloc_free(call);
}

/*
  called when we get a new connection
*/
static void kdc_tcp_accept(struct stream_connection *conn)
{
        struct kdc_socket *kdc_socket;
        struct kdc_tcp_connection *kdc_conn;
        struct tevent_req *subreq;
        int rc;

        kdc_conn = talloc_zero(conn, struct kdc_tcp_connection);
        if (kdc_conn == NULL) {
                stream_terminate_connection(conn,
                                "kdc_tcp_accept: out of memory");
                return;
        }

        kdc_conn->send_queue = tevent_queue_create(conn, "kdc_tcp_accept");
        if (kdc_conn->send_queue == NULL) {
                stream_terminate_connection(conn,
                                "kdc_tcp_accept: out of memory");
                return;
        }

        kdc_socket = talloc_get_type(conn->private_data, struct kdc_socket);

        TALLOC_FREE(conn->event.fde);

        rc = tstream_bsd_existing_socket(kdc_conn,
                        socket_get_fd(conn->socket),
                        &kdc_conn->tstream);
        if (rc < 0) {
                stream_terminate_connection(conn,
                                "kdc_tcp_accept: out of memory");
                return;
        }

        kdc_conn->conn = conn;
        kdc_conn->kdc_socket = kdc_socket;
        conn->private_data = kdc_conn;

        /*
         * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
         * packet_full_request_u32 provides the pdu length then.
         */
        subreq = tstream_read_pdu_blob_send(kdc_conn,
                                            kdc_conn->conn->event.ctx,
                                            kdc_conn->tstream,
                                            4, /* initial_read_size */
                                            packet_full_request_u32,
                                            kdc_conn);
        if (subreq == NULL) {
                kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_accept: "
                                "no memory for tstream_read_pdu_blob_send");
                return;
        }
        tevent_req_set_callback(subreq, kdc_tcp_call_loop, kdc_conn);
}

static const struct stream_server_ops kdc_tcp_stream_ops = {
        .name                   = "kdc_tcp",
        .accept_connection      = kdc_tcp_accept,
        .recv_handler           = kdc_tcp_recv,
        .send_handler           = kdc_tcp_send
};

/* hold information about one kdc/kpasswd udp socket */
struct kdc_udp_socket {
        struct kdc_socket *kdc_socket;
        struct tdgram_context *dgram;
        struct tevent_queue *send_queue;
};

struct kdc_udp_call {
        struct kdc_udp_socket *sock;
        struct tsocket_address *src;
        DATA_BLOB in;
        DATA_BLOB out;
};

static void kdc_udp_call_proxy_done(struct tevent_req *subreq);
static void kdc_udp_call_sendto_done(struct tevent_req *subreq);

static void kdc_udp_call_loop(struct tevent_req *subreq)
{
        struct kdc_udp_socket *sock = tevent_req_callback_data(subreq,
                                      struct kdc_udp_socket);
        struct kdc_udp_call *call;
        uint8_t *buf;
        ssize_t len;
        int sys_errno;
        enum kdc_process_ret ret;

        call = talloc(sock, struct kdc_udp_call);
        if (call == NULL) {
                talloc_free(call);
                goto done;
        }
        call->sock = sock;

        len = tdgram_recvfrom_recv(subreq, &sys_errno,
                                   call, &buf, &call->src);
        TALLOC_FREE(subreq);
        if (len == -1) {
                talloc_free(call);
                goto done;
        }

        call->in.data = buf;
        call->in.length = len;

        DEBUG(10,("Received krb5 UDP packet of length %lu from %s\n",
                 (long)call->in.length,
                 tsocket_address_string(call->src, call)));

        /* Call krb5 */
        ret = sock->kdc_socket->process(sock->kdc_socket->kdc,
                                       call,
                                       &call->in,
                                       &call->out,
                                       call->src,
                                       sock->kdc_socket->local_address,
                                       1 /* Datagram */);
        if (ret == KDC_PROCESS_FAILED) {
                talloc_free(call);
                goto done;
        }

        if (ret == KDC_PROCESS_PROXY) {
                uint16_t port;

                if (!sock->kdc_socket->kdc->am_rodc) {
                        DEBUG(0,("kdc_udp_call_loop: proxying requested when not RODC"));
                        talloc_free(call);
                        goto done;
                }

                port = tsocket_address_inet_port(sock->kdc_socket->local_address);

                subreq = kdc_udp_proxy_send(call,
                                            sock->kdc_socket->kdc->task->event_ctx,
                                            sock->kdc_socket->kdc,
                                            port,
                                            call->in);
                if (subreq == NULL) {
                        talloc_free(call);
                        goto done;
                }
                tevent_req_set_callback(subreq, kdc_udp_call_proxy_done, call);
                goto done;
        }

        subreq = tdgram_sendto_queue_send(call,
                                          sock->kdc_socket->kdc->task->event_ctx,
                                          sock->dgram,
                                          sock->send_queue,
                                          call->out.data,
                                          call->out.length,
                                          call->src);
        if (subreq == NULL) {
                talloc_free(call);
                goto done;
        }
        tevent_req_set_callback(subreq, kdc_udp_call_sendto_done, call);

done:
        subreq = tdgram_recvfrom_send(sock,
                                      sock->kdc_socket->kdc->task->event_ctx,
                                      sock->dgram);
        if (subreq == NULL) {
                task_server_terminate(sock->kdc_socket->kdc->task,
                                      "no memory for tdgram_recvfrom_send",
                                      true);
                return;
        }
        tevent_req_set_callback(subreq, kdc_udp_call_loop, sock);
}

static void kdc_udp_call_proxy_done(struct tevent_req *subreq)
{
        struct kdc_udp_call *call =
                tevent_req_callback_data(subreq,
                struct kdc_udp_call);
        NTSTATUS status;

        status = kdc_udp_proxy_recv(subreq, call, &call->out);
        TALLOC_FREE(subreq);
        if (!NT_STATUS_IS_OK(status)) {
                /* generate an error packet */
                status = kdc_proxy_unavailable_error(call->sock->kdc_socket->kdc,
                                                     call, &call->out);
        }

        if (!NT_STATUS_IS_OK(status)) {
                talloc_free(call);
                return;
        }

        subreq = tdgram_sendto_queue_send(call,
                                          call->sock->kdc_socket->kdc->task->event_ctx,
                                          call->sock->dgram,
                                          call->sock->send_queue,
                                          call->out.data,
                                          call->out.length,
                                          call->src);
        if (subreq == NULL) {
                talloc_free(call);
                return;
        }

        tevent_req_set_callback(subreq, kdc_udp_call_sendto_done, call);
}

static void kdc_udp_call_sendto_done(struct tevent_req *subreq)
{
        struct kdc_udp_call *call = tevent_req_callback_data(subreq,
                                       struct kdc_udp_call);
        ssize_t ret;
        int sys_errno;

        ret = tdgram_sendto_queue_recv(subreq, &sys_errno);

        /* We don't care about errors */

        talloc_free(call);
}

/*
  start listening on the given address
*/
static NTSTATUS kdc_add_socket(struct kdc_server *kdc,
                               const struct model_ops *model_ops,
                               const char *name,
                               const char *address,
                               uint16_t port,
                               kdc_process_fn_t process,
                               bool udp_only)
{
        struct kdc_socket *kdc_socket;
        struct kdc_udp_socket *kdc_udp_socket;
        struct tevent_req *udpsubreq;
        NTSTATUS status;
        int ret;

        kdc_socket = talloc(kdc, struct kdc_socket);
        NT_STATUS_HAVE_NO_MEMORY(kdc_socket);

        kdc_socket->kdc = kdc;
        kdc_socket->process = process;

        ret = tsocket_address_inet_from_strings(kdc_socket, "ip",
                                                address, port,
                                                &kdc_socket->local_address);
        if (ret != 0) {
                status = map_nt_error_from_unix(errno);
                return status;
        }

        if (!udp_only) {
                status = stream_setup_socket(kdc->task,
                                             kdc->task->event_ctx,
                                             kdc->task->lp_ctx,
                                             model_ops,
                                             &kdc_tcp_stream_ops,
                                             "ip", address, &port,
                                             lpcfg_socket_options(kdc->task->lp_ctx),
                                             kdc_socket);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
                                 address, port, nt_errstr(status)));
                        talloc_free(kdc_socket);
                        return status;
                }
        }

        kdc_udp_socket = talloc(kdc_socket, struct kdc_udp_socket);
        NT_STATUS_HAVE_NO_MEMORY(kdc_udp_socket);

        kdc_udp_socket->kdc_socket = kdc_socket;

        ret = tdgram_inet_udp_socket(kdc_socket->local_address,
                                     NULL,
                                     kdc_udp_socket,
                                     &kdc_udp_socket->dgram);
        if (ret != 0) {
                status = map_nt_error_from_unix(errno);
                DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
                         address, port, nt_errstr(status)));
                return status;
        }

        kdc_udp_socket->send_queue = tevent_queue_create(kdc_udp_socket,
                                                         "kdc_udp_send_queue");
        NT_STATUS_HAVE_NO_MEMORY(kdc_udp_socket->send_queue);

        udpsubreq = tdgram_recvfrom_send(kdc_udp_socket,
                                         kdc->task->event_ctx,
                                         kdc_udp_socket->dgram);
        NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
        tevent_req_set_callback(udpsubreq, kdc_udp_call_loop, kdc_udp_socket);

        return NT_STATUS_OK;
}


/*
  setup our listening sockets on the configured network interfaces
*/
static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc, struct loadparm_context *lp_ctx,
                                       struct interface *ifaces)
{
        const struct model_ops *model_ops;
        int num_interfaces;
        TALLOC_CTX *tmp_ctx = talloc_new(kdc);
        NTSTATUS status;
        int i;
        uint16_t kdc_port = lpcfg_krb5_port(lp_ctx);
        uint16_t kpasswd_port = lpcfg_kpasswd_port(lp_ctx);
        bool done_wildcard = false;

        /* within the kdc task we want to be a single process, so
           ask for the single process model ops and pass these to the
           stream_setup_socket() call. */
        model_ops = process_model_startup("single");
        if (!model_ops) {
                DEBUG(0,("Can't find 'single' process model_ops\n"));
                return NT_STATUS_INTERNAL_ERROR;
        }

        num_interfaces = iface_count(ifaces);

        /* if we are allowing incoming packets from any address, then
           we need to bind to the wildcard address */
        if (!lpcfg_bind_interfaces_only(lp_ctx)) {
                if (kdc_port) {
                        status = kdc_add_socket(kdc, model_ops,
                                                "kdc", "0.0.0.0", kdc_port,
                                                kdc_process, false);
                        NT_STATUS_NOT_OK_RETURN(status);
                }

                if (kpasswd_port) {
                        status = kdc_add_socket(kdc, model_ops,
                                                "kpasswd", "0.0.0.0", kpasswd_port,
                                                kpasswdd_process, false);
                        NT_STATUS_NOT_OK_RETURN(status);
                }
                done_wildcard = true;
        }

        for (i=0; i<num_interfaces; i++) {
                const char *address = talloc_strdup(tmp_ctx, iface_n_ip(ifaces, i));

                if (kdc_port) {
                        status = kdc_add_socket(kdc, model_ops,
                                                "kdc", address, kdc_port,
                                                kdc_process, done_wildcard);
                        NT_STATUS_NOT_OK_RETURN(status);
                }

                if (kpasswd_port) {
                        status = kdc_add_socket(kdc, model_ops,
                                                "kpasswd", address, kpasswd_port,
                                                kpasswdd_process, done_wildcard);
                        NT_STATUS_NOT_OK_RETURN(status);
                }
        }

        talloc_free(tmp_ctx);

        return NT_STATUS_OK;
}


static NTSTATUS kdc_check_generic_kerberos(struct irpc_message *msg,
                                 struct kdc_check_generic_kerberos *r)
{
        struct PAC_Validate pac_validate;
        DATA_BLOB srv_sig;
        struct PAC_SIGNATURE_DATA kdc_sig;
        struct kdc_server *kdc = talloc_get_type(msg->private_data, struct kdc_server);
        enum ndr_err_code ndr_err;
        krb5_enctype etype;
        int ret;
        hdb_entry_ex ent;
        krb5_principal principal;
        krb5_keyblock keyblock;
        Key *key;

        /* There is no reply to this request */
        r->out.generic_reply = data_blob(NULL, 0);

        ndr_err = ndr_pull_struct_blob(&r->in.generic_request, msg, &pac_validate,
                                       (ndr_pull_flags_fn_t)ndr_pull_PAC_Validate);
        if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
                return NT_STATUS_INVALID_PARAMETER;
        }

        if (pac_validate.MessageType != 3) {
                /* We don't implement any other message types - such as certificate validation - yet */
                return NT_STATUS_INVALID_PARAMETER;
        }

        if (pac_validate.ChecksumAndSignature.length != (pac_validate.ChecksumLength + pac_validate.SignatureLength)
            || pac_validate.ChecksumAndSignature.length < pac_validate.ChecksumLength
            || pac_validate.ChecksumAndSignature.length < pac_validate.SignatureLength ) {
                return NT_STATUS_INVALID_PARAMETER;
        }

        srv_sig = data_blob_const(pac_validate.ChecksumAndSignature.data,
                                  pac_validate.ChecksumLength);

        if (pac_validate.SignatureType == CKSUMTYPE_HMAC_MD5) {
                etype = ETYPE_ARCFOUR_HMAC_MD5;
        } else {
                ret = krb5_cksumtype_to_enctype(kdc->smb_krb5_context->krb5_context, pac_validate.SignatureType,
                                                &etype);
                if (ret != 0) {
                        return NT_STATUS_LOGON_FAILURE;
                }
        }

        ret = krb5_make_principal(kdc->smb_krb5_context->krb5_context, &principal,
                                  lpcfg_realm(kdc->task->lp_ctx),
                                  "krbtgt", lpcfg_realm(kdc->task->lp_ctx),
                                  NULL);

        if (ret != 0) {
                return NT_STATUS_NO_MEMORY;
        }

        ret = kdc->config->db[0]->hdb_fetch_kvno(kdc->smb_krb5_context->krb5_context,
                                                 kdc->config->db[0],
                                                 principal,
                                                 HDB_F_GET_KRBTGT | HDB_F_DECRYPT,
                                                 0,
                                                 &ent);
        
        if (ret != 0) {
                hdb_free_entry(kdc->smb_krb5_context->krb5_context, &ent);
                krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);

                return NT_STATUS_LOGON_FAILURE;
        }

        ret = hdb_enctype2key(kdc->smb_krb5_context->krb5_context, &ent.entry, etype, &key);

        if (ret != 0) {
                hdb_free_entry(kdc->smb_krb5_context->krb5_context, &ent);
                krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
                return NT_STATUS_LOGON_FAILURE;
        }

        keyblock = key->key;

        kdc_sig.type = pac_validate.SignatureType;
        kdc_sig.signature = data_blob_const(&pac_validate.ChecksumAndSignature.data[pac_validate.ChecksumLength],
                                            pac_validate.SignatureLength);
        ret = check_pac_checksum(msg, srv_sig, &kdc_sig,
                           kdc->smb_krb5_context->krb5_context, &keyblock);

        hdb_free_entry(kdc->smb_krb5_context->krb5_context, &ent);
        krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);

        if (ret != 0) {
                return NT_STATUS_LOGON_FAILURE;
        }

        return NT_STATUS_OK;
}


/*
  startup the kdc task
*/
static void kdc_task_init(struct task_server *task)
{
        struct kdc_server *kdc;
        NTSTATUS status;
        krb5_error_code ret;
        struct interface *ifaces;
        int ldb_ret;

        switch (lpcfg_server_role(task->lp_ctx)) {
        case ROLE_STANDALONE:
                task_server_terminate(task, "kdc: no KDC required in standalone configuration", false);
                return;
        case ROLE_DOMAIN_MEMBER:
                task_server_terminate(task, "kdc: no KDC required in member server configuration", false);
                return;
        case ROLE_DOMAIN_CONTROLLER:
                /* Yes, we want a KDC */
                break;
        }

        load_interfaces(task, lpcfg_interfaces(task->lp_ctx), &ifaces);

        if (iface_count(ifaces) == 0) {
                task_server_terminate(task, "kdc: no network interfaces configured", false);
                return;
        }

        task_server_set_title(task, "task[kdc]");

        kdc = talloc_zero(task, struct kdc_server);
        if (kdc == NULL) {
                task_server_terminate(task, "kdc: out of memory", true);
                return;
        }

        kdc->task = task;


        /* get a samdb connection */
        kdc->samdb = samdb_connect(kdc, kdc->task->event_ctx, kdc->task->lp_ctx,
                                   system_session(kdc->task->lp_ctx), 0);
        if (!kdc->samdb) {
                DEBUG(1,("kdc_task_init: unable to connect to samdb\n"));
                task_server_terminate(task, "kdc: krb5_init_context samdb connect failed", true);
                return;
        }

        ldb_ret = samdb_rodc(kdc->samdb, &kdc->am_rodc);
        if (ldb_ret != LDB_SUCCESS) {
                DEBUG(1, ("kdc_task_init: Cannot determine if we are an RODC: %s\n",
                          ldb_errstring(kdc->samdb)));
                task_server_terminate(task, "kdc: krb5_init_context samdb RODC connect failed", true);
                return;
        }

        kdc->proxy_timeout = lpcfg_parm_int(kdc->task->lp_ctx, NULL, "kdc", "proxy timeout", 5);

        initialize_krb5_error_table();

        ret = smb_krb5_init_context(kdc, task->event_ctx, task->lp_ctx, &kdc->smb_krb5_context);
        if (ret) {
                DEBUG(1,("kdc_task_init: krb5_init_context failed (%s)\n",
                         error_message(ret)));
                task_server_terminate(task, "kdc: krb5_init_context failed", true);
                return;
        }

        krb5_add_et_list(kdc->smb_krb5_context->krb5_context, initialize_hdb_error_table_r);

        ret = krb5_kdc_get_config(kdc->smb_krb5_context->krb5_context,
                                  &kdc->config);
        if(ret) {
                task_server_terminate(task, "kdc: failed to get KDC configuration", true);
                return;
        }

        kdc->config->logf = kdc->smb_krb5_context->logf;
        kdc->config->db = talloc(kdc, struct HDB *);
        if (!kdc->config->db) {
                task_server_terminate(task, "kdc: out of memory", true);
                return;
        }
        kdc->config->num_db = 1;

        /* Register hdb-samba4 hooks for use as a keytab */

        kdc->base_ctx = talloc_zero(kdc, struct samba_kdc_base_context);
        if (!kdc->base_ctx) {
                task_server_terminate(task, "kdc: out of memory", true);
                return;
        }

        kdc->base_ctx->ev_ctx = task->event_ctx;
        kdc->base_ctx->lp_ctx = task->lp_ctx;

        status = hdb_samba4_create_kdc(kdc->base_ctx,
                                       kdc->smb_krb5_context->krb5_context,
                                       &kdc->config->db[0]);
        if (!NT_STATUS_IS_OK(status)) {
                task_server_terminate(task, "kdc: hdb_samba4_create_kdc (setup KDC database) failed", true);
                return;
        }

        ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
                                   PLUGIN_TYPE_DATA, "hdb",
                                   &hdb_samba4);
        if(ret) {
                task_server_terminate(task, "kdc: failed to register hdb plugin", true);
                return;
        }

        ret = krb5_kt_register(kdc->smb_krb5_context->krb5_context, &hdb_kt_ops);
        if(ret) {
                task_server_terminate(task, "kdc: failed to register keytab plugin", true);
                return;
        }

        /* Register WinDC hooks */
        ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
                                   PLUGIN_TYPE_DATA, "windc",
                                   &windc_plugin_table);
        if(ret) {
                task_server_terminate(task, "kdc: failed to register windc plugin", true);
                return;
        }

        ret = krb5_kdc_windc_init(kdc->smb_krb5_context->krb5_context);

        if(ret) {
                task_server_terminate(task, "kdc: failed to init windc plugin", true);
                return;
        }

        ret = krb5_kdc_pkinit_config(kdc->smb_krb5_context->krb5_context, kdc->config);

        if(ret) {
                task_server_terminate(task, "kdc: failed to init kdc pkinit subsystem", true);
                return;
        }

        /* start listening on the configured network interfaces */
        status = kdc_startup_interfaces(kdc, task->lp_ctx, ifaces);
        if (!NT_STATUS_IS_OK(status)) {
                task_server_terminate(task, "kdc failed to setup interfaces", true);
                return;
        }

        status = IRPC_REGISTER(task->msg_ctx, irpc, KDC_CHECK_GENERIC_KERBEROS,
                               kdc_check_generic_kerberos, kdc);
        if (!NT_STATUS_IS_OK(status)) {
                task_server_terminate(task, "kdc failed to setup monitoring", true);
                return;
        }

        irpc_add_name(task->msg_ctx, "kdc_server");
}


/* called at smbd startup - register ourselves as a server service */
NTSTATUS server_service_kdc_init(void)
{
        return register_server_service("kdc", kdc_task_init);
}