kdc.c

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/* 
   Unix SMB/CIFS implementation.

   KDC Server startup

   Copyright (C) Andrew Bartlett <[e-mail]> 2005
   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/service_task.h"
#include "smbd/service.h"
#include "smbd/service_stream.h"
#include "smbd/process_model.h"
#include "lib/events/events.h"
#include "lib/socket/socket.h"
#include "kdc/kdc.h"
#include "system/network.h"
#include "lib/util/dlinklist.h"
#include "lib/messaging/irpc.h"
#include "lib/stream/packet.h"
#include "librpc/gen_ndr/samr.h"
#include "lib/socket/netif.h"
#include "heimdal/kdc/windc_plugin.h"
#include "heimdal/lib/krb5/krb5_locl.h"
#include "heimdal/kdc/kdc_locl.h"
#include "param/param.h"


/* Disgusting hack to get a mem_ctx and lp_ctx into the hdb plugin, when 
 * used as a keytab */
TALLOC_CTX *kdc_mem_ctx;
struct loadparm_context *kdc_lp_ctx;

/* hold all the info needed to send a reply */
struct kdc_reply {
	struct kdc_reply *next, *prev;
	struct socket_address *dest;
	DATA_BLOB packet;
};

typedef bool (*kdc_process_fn_t)(struct kdc_server *kdc,
				 TALLOC_CTX *mem_ctx, 
				 DATA_BLOB *input, 
				 DATA_BLOB *reply,
				 struct socket_address *peer_addr, 
				 struct socket_address *my_addr, 
				 int datagram);

/* hold information about one kdc socket */
struct kdc_socket {
	struct socket_context *sock;
	struct kdc_server *kdc;
	struct fd_event *fde;

	/* a queue of outgoing replies that have been deferred */
	struct kdc_reply *send_queue;

	kdc_process_fn_t process;
};
/*
  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_server *kdc;

	struct packet_context *packet;

	kdc_process_fn_t process;
};

/*
  handle fd send events on a KDC socket
*/
static void kdc_send_handler(struct kdc_socket *kdc_socket)
{
	while (kdc_socket->send_queue) {
		struct kdc_reply *rep = kdc_socket->send_queue;
		NTSTATUS status;
		size_t sendlen;

		status = socket_sendto(kdc_socket->sock, &rep->packet, &sendlen,
				       rep->dest);
		if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
			break;
		}
		if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_BUFFER_SIZE)) {
			/* Replace with a krb err, response to big */
		}
		
		DLIST_REMOVE(kdc_socket->send_queue, rep);
		talloc_free(rep);
	}

	if (kdc_socket->send_queue == NULL) {
		EVENT_FD_NOT_WRITEABLE(kdc_socket->fde);
	}
}


/*
  handle fd recv events on a KDC socket
*/
static void kdc_recv_handler(struct kdc_socket *kdc_socket)
{
	NTSTATUS status;
	TALLOC_CTX *tmp_ctx = talloc_new(kdc_socket);
	DATA_BLOB blob;
	struct kdc_reply *rep;
	DATA_BLOB reply;
	size_t nread, dsize;
	struct socket_address *src;
	struct socket_address *my_addr;
	int ret;

	status = socket_pending(kdc_socket->sock, &dsize);
	if (!NT_STATUS_IS_OK(status)) {
		talloc_free(tmp_ctx);
		return;
	}

	blob = data_blob_talloc(tmp_ctx, NULL, dsize);
	if (blob.data == NULL) {
		/* hope this is a temporary low memory condition */
		talloc_free(tmp_ctx);
		return;
	}

	status = socket_recvfrom(kdc_socket->sock, blob.data, blob.length, &nread,
				 tmp_ctx, &src);
	if (!NT_STATUS_IS_OK(status)) {
		talloc_free(tmp_ctx);
		return;
	}
	blob.length = nread;
	
	DEBUG(10,("Received krb5 UDP packet of length %lu from %s:%u\n", 
		 (long)blob.length, src->addr, (uint16_t)src->port));
	
	my_addr = socket_get_my_addr(kdc_socket->sock, tmp_ctx);
	if (!my_addr) {
		talloc_free(tmp_ctx);
		return;
	}


	/* Call krb5 */
	ret = kdc_socket->process(kdc_socket->kdc, 
				  tmp_ctx, 
				  &blob,  
				  &reply,
				  src, my_addr,
				  1 /* Datagram */);
	if (!ret) {
		talloc_free(tmp_ctx);
		return;
	}

	/* queue a pending reply */
	rep = talloc(kdc_socket, struct kdc_reply);
	if (rep == NULL) {
		talloc_free(tmp_ctx);
		return;
	}
	rep->dest         = talloc_steal(rep, src);
	rep->packet       = reply;
	talloc_steal(rep, reply.data);

	if (rep->packet.data == NULL) {
		talloc_free(rep);
		talloc_free(tmp_ctx);
		return;
	}

	DLIST_ADD_END(kdc_socket->send_queue, rep, struct kdc_reply *);
	EVENT_FD_WRITEABLE(kdc_socket->fde);
	talloc_free(tmp_ctx);
}

/*
  handle fd events on a KDC socket
*/
static void kdc_socket_handler(struct event_context *ev, struct fd_event *fde,
			       uint16_t flags, void *private)
{
	struct kdc_socket *kdc_socket = talloc_get_type(private, struct kdc_socket);
	if (flags & EVENT_FD_WRITE) {
		kdc_send_handler(kdc_socket);
	} 
	if (flags & EVENT_FD_READ) {
		kdc_recv_handler(kdc_socket);
	}
}

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

/*
  receive a full packet on a KDC connection
*/
static NTSTATUS kdc_tcp_recv(void *private, DATA_BLOB blob)
{
	struct kdc_tcp_connection *kdcconn = talloc_get_type(private, 
							     struct kdc_tcp_connection);
	NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
	TALLOC_CTX *tmp_ctx = talloc_new(kdcconn);
	int ret;
	DATA_BLOB input, reply;
	struct socket_address *src_addr;
	struct socket_address *my_addr;

	talloc_steal(tmp_ctx, blob.data);

	src_addr = socket_get_peer_addr(kdcconn->conn->socket, tmp_ctx);
	if (!src_addr) {
		talloc_free(tmp_ctx);
		return NT_STATUS_NO_MEMORY;
	}

	my_addr = socket_get_my_addr(kdcconn->conn->socket, tmp_ctx);
	if (!my_addr) {
		talloc_free(tmp_ctx);
		return NT_STATUS_NO_MEMORY;
	}

	/* Call krb5 */
	input = data_blob_const(blob.data + 4, blob.length - 4); 

	ret = kdcconn->process(kdcconn->kdc, 
			       tmp_ctx,
			       &input,
			       &reply,
			       src_addr,
			       my_addr,
			       0 /* Not datagram */);
	if (!ret) {
		talloc_free(tmp_ctx);
		return NT_STATUS_INTERNAL_ERROR;
	}

	/* and now encode the reply */
	blob = data_blob_talloc(kdcconn, NULL, reply.length + 4);
	if (!blob.data) {
		talloc_free(tmp_ctx);
		return NT_STATUS_NO_MEMORY;
	}

	RSIVAL(blob.data, 0, reply.length);
	memcpy(blob.data + 4, reply.data, reply.length);	

	status = packet_send(kdcconn->packet, blob);
	if (!NT_STATUS_IS_OK(status)) {
		talloc_free(tmp_ctx);
		return status;
	}

	/* the call isn't needed any more */
	talloc_free(tmp_ctx);
	return NT_STATUS_OK;
}

/*
  receive some data on a KDC connection
*/
static void kdc_tcp_recv_handler(struct stream_connection *conn, uint16_t flags)
{
	struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private, 
							     struct kdc_tcp_connection);
	packet_recv(kdcconn->packet);
}

/*
  called on a tcp recv error
*/
static void kdc_tcp_recv_error(void *private, NTSTATUS status)
{
	struct kdc_tcp_connection *kdcconn = talloc_get_type(private, struct kdc_tcp_connection);
	kdc_tcp_terminate_connection(kdcconn, nt_errstr(status));
}

/*
  called when we can write to a connection
*/
static void kdc_tcp_send(struct stream_connection *conn, uint16_t flags)
{
	struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private, 
							     struct kdc_tcp_connection);
	packet_queue_run(kdcconn->packet);
}

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

static bool kdc_process(struct kdc_server *kdc,
			TALLOC_CTX *mem_ctx, 
			DATA_BLOB *input, 
			DATA_BLOB *reply,
			struct socket_address *peer_addr, 
			struct socket_address *my_addr,
			int datagram_reply)
{
	int ret;	
	krb5_data k5_reply;
	krb5_data_zero(&k5_reply);

	krb5_kdc_update_time(NULL);

	DEBUG(10,("Received KDC packet of length %lu from %s:%d\n", 
		  (long)input->length - 4, peer_addr->addr, peer_addr->port));

	ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context, 
					    kdc->config,
					    input->data, input->length,
					    &k5_reply,