winbindd_cm.c

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/* 
   Unix SMB/CIFS implementation.

   Winbind daemon connection manager

   Copyright (C) Tim Potter                2001
   Copyright (C) Andrew Bartlett           2002
   Copyright (C) Gerald (Jerry) Carter     2003-2005.
   Copyright (C) Volker Lendecke           2004-2005
   
   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 2 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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/*
   We need to manage connections to domain controllers without having to
   mess up the main winbindd code with other issues.  The aim of the
   connection manager is to:
  
       - make connections to domain controllers and cache them
       - re-establish connections when networks or servers go down
       - centralise the policy on connection timeouts, domain controller
	 selection etc
       - manage re-entrancy for when winbindd becomes able to handle
	 multiple outstanding rpc requests
  
   Why not have connection management as part of the rpc layer like tng?
   Good question.  This code may morph into libsmb/rpc_cache.c or something
   like that but at the moment it's simply staying as part of winbind.	I
   think the TNG architecture of forcing every user of the rpc layer to use
   the connection caching system is a bad idea.	 It should be an optional
   method of using the routines.

   The TNG design is quite good but I disagree with some aspects of the
   implementation. -tpot

 */

/*
   TODO:

     - I'm pretty annoyed by all the make_nmb_name() stuff.  It should be
       moved down into another function.

     - Take care when destroying cli_structs as they can be shared between
       various sam handles.

 */

#include "includes.h"
#include "winbindd.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_WINBIND


/* Choose between anonymous or authenticated connections.  We need to use
   an authenticated connection if DCs have the RestrictAnonymous registry
   entry set > 0, or the "Additional restrictions for anonymous
   connections" set in the win2k Local Security Policy. 
   
   Caller to free() result in domain, username, password
*/

static void cm_get_ipc_userpass(char **username, char **domain, char **password)
{
	*username = secrets_fetch(SECRETS_AUTH_USER, NULL);
	*domain = secrets_fetch(SECRETS_AUTH_DOMAIN, NULL);
	*password = secrets_fetch(SECRETS_AUTH_PASSWORD, NULL);
	
	if (*username && **username) {

		if (!*domain || !**domain)
			*domain = smb_xstrdup(lp_workgroup());
		
		if (!*password || !**password)
			*password = smb_xstrdup("");

		DEBUG(3, ("cm_get_ipc_userpass: Retrieved auth-user from secrets.tdb [%s\\%s]\n", 
			  *domain, *username));

	} else {
		DEBUG(3, ("cm_get_ipc_userpass: No auth-user defined\n"));
		*username = smb_xstrdup("");
		*domain = smb_xstrdup("");
		*password = smb_xstrdup("");
	}
}

static BOOL get_dc_name_via_netlogon(const struct winbindd_domain *domain,
				     fstring dcname, struct in_addr *dc_ip)
{
	struct winbindd_domain *our_domain = NULL;
	struct rpc_pipe_client *netlogon_pipe = NULL;
	NTSTATUS result;
	TALLOC_CTX *mem_ctx;

	fstring tmp;
	char *p;

	/* Hmmmm. We can only open one connection to the NETLOGON pipe at the
	 * moment.... */

	if (IS_DC) {
		return False;
	}

	if (domain->primary) {
		return False;
	}

	our_domain = find_our_domain();

	if ((mem_ctx = talloc_init("get_dc_name_via_netlogon")) == NULL) {
		return False;
	}

	result = cm_connect_netlogon(our_domain, &netlogon_pipe);
	if (!NT_STATUS_IS_OK(result)) {
		return False;
	}

	result = rpccli_netlogon_getdcname(netlogon_pipe, mem_ctx, our_domain->dcname,
					   domain->name, tmp);

	talloc_destroy(mem_ctx);

	if (!NT_STATUS_IS_OK(result)) {
		DEBUG(10, ("rpccli_netlogon_getdcname failed: %s\n",
			   nt_errstr(result)));
		return False;
	}

	/* cli_netlogon_getdcname gives us a name with \\ */
	p = tmp;
	if (*p == '\\') {
		p+=1;
	}
	if (*p == '\\') {
		p+=1;
	}

	fstrcpy(dcname, p);

	DEBUG(10, ("rpccli_netlogon_getdcname returned %s\n", dcname));

	if (!resolve_name(dcname, dc_ip, 0x20)) {
		return False;
	}

	return True;
}

/************************************************************************
 Given a fd with a just-connected TCP connection to a DC, open a connection
 to the pipe.
************************************************************************/

static NTSTATUS cm_prepare_connection(const struct winbindd_domain *domain,
				      const int sockfd,
				      const char *controller,
				      struct cli_state **cli,
				      BOOL *retry)
{
	char *machine_password, *machine_krb5_principal, *machine_account;
	char *ipc_username, *ipc_domain, *ipc_password;

	BOOL got_mutex;
	BOOL add_failed_connection = True;

	NTSTATUS result = NT_STATUS_UNSUCCESSFUL;

	struct sockaddr peeraddr;
	socklen_t peeraddr_len;

	struct sockaddr_in *peeraddr_in = (struct sockaddr_in *)&peeraddr;

	machine_password = secrets_fetch_machine_password(lp_workgroup(), NULL,
							  NULL);
	
	if (asprintf(&machine_account, "%s$", global_myname()) == -1) {
		SAFE_FREE(machine_password);
		return NT_STATUS_NO_MEMORY;
	}

	if (asprintf(&machine_krb5_principal, "%s$@%s", global_myname(),
		     lp_realm()) == -1) {
		SAFE_FREE(machine_account);
		SAFE_FREE(machine_password);
		return NT_STATUS_NO_MEMORY;
	}

	cm_get_ipc_userpass(&ipc_username, &ipc_domain, &ipc_password);

	*retry = True;

	got_mutex = secrets_named_mutex(controller,
					WINBIND_SERVER_MUTEX_WAIT_TIME);

	if (!got_mutex) {
		DEBUG(0,("cm_prepare_connection: mutex grab failed for %s\n",
			 controller));
		result = NT_STATUS_POSSIBLE_DEADLOCK;
		goto done;
	}

	if ((*cli = cli_initialise(NULL)) == NULL) {
		DEBUG(1, ("Could not cli_initialize\n"));
		result = NT_STATUS_NO_MEMORY;
		goto done;
	}

	(*cli)->timeout = 10000; 	/* 10 seconds */
	(*cli)->fd = sockfd;
	fstrcpy((*cli)->desthost, controller);
	(*cli)->use_kerberos = True;

	peeraddr_len = sizeof(peeraddr);

	if ((getpeername((*cli)->fd, &peeraddr, &peeraddr_len) != 0) ||
	    (peeraddr_len != sizeof(struct sockaddr_in)) ||
	    (peeraddr_in->sin_family != PF_INET))
	{
		DEBUG(0,("cm_prepare_connection: %s\n", strerror(errno)));
		goto done;
	}

	if (ntohs(peeraddr_in->sin_port) == 139) {
		struct nmb_name calling;
		struct nmb_name called;

		make_nmb_name(&calling, global_myname(), 0x0);
		make_nmb_name(&called, "*SMBSERVER", 0x20);

		if (!cli_session_request(*cli, &calling, &called)) {
			DEBUG(8, ("cli_session_request failed for %s\n",
				  controller));
			goto done;
		}
	}

	cli_setup_signing_state(*cli, Undefined);

	if (!cli_negprot(*cli)) {
		DEBUG(1, ("cli_negprot failed\n"));
		cli_shutdown(*cli);
		goto done;
	}

			
	if ((*cli)->protocol >= PROTOCOL_NT1 && (*cli)->capabilities & CAP_EXTENDED_SECURITY) {
		ADS_STATUS ads_status;

		if (lp_security() == SEC_ADS) {

			/* Try a krb5 session */

			(*cli)->use_kerberos = True;
			DEBUG(5, ("connecting to %s from %s with kerberos principal "
				  "[%s]\n", controller, global_myname(),
				  machine_krb5_principal));

			ads_status = cli_session_setup_spnego(*cli,
							      machine_krb5_principal, 
							      machine_password, 
							      lp_workgroup());

			if (!ADS_ERR_OK(ads_status)) {
				DEBUG(4,("failed kerberos session setup with %s\n",
					 ads_errstr(ads_status)));
			}

			result = ads_ntstatus(ads_status);
			if (NT_STATUS_IS_OK(result)) {
				/* Ensure creds are stored for NTLMSSP authenticated pipe access. */
				cli_init_creds(*cli, machine_account, lp_workgroup(), machine_password);
				goto session_setup_done;
			}
		}

		/* Fall back to non-kerberos session setup using NTLMSSP SPNEGO with the machine account. */
		(*cli)->use_kerberos = False;

		DEBUG(5, ("connecting to %s from %s with username "
			  "[%s]\\[%s]\n",  controller, global_myname(),
			  lp_workgroup(), machine_account));

		ads_status = cli_session_setup_spnego(*cli,
						      machine_account, 
						      machine_password, 
						      lp_workgroup());
		if (!ADS_ERR_OK(ads_status)) {
			DEBUG(4, ("authenticated session setup failed with %s\n",
				ads_errstr(ads_status)));
		}

		result = ads_ntstatus(ads_status);
		if (NT_STATUS_IS_OK(result)) {
			/* Ensure creds are stored for NTLMSSP authenticated pipe access. */
			cli_init_creds(*cli, machine_account, lp_workgroup(), machine_password);
			goto session_setup_done;
		}
	}

	/* Fall back to non-kerberos session setup */

	(*cli)->use_kerberos = False;

	if ((((*cli)->sec_mode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) != 0) &&
	    (strlen(ipc_username) > 0)) {

		/* Only try authenticated if we have a username */

		DEBUG(5, ("connecting to %s from %s with username "
			  "[%s]\\[%s]\n",  controller, global_myname(),
			  ipc_domain, ipc_username));

		if (cli_session_setup(*cli, ipc_username,
				      ipc_password, strlen(ipc_password)+1,
				      ipc_password, strlen(ipc_password)+1,
				      ipc_domain)) {
			/* Successful logon with given username. */
			cli_init_creds(*cli, ipc_username, ipc_domain, ipc_password);
			goto session_setup_done;
		} else {
			DEBUG(4, ("authenticated session setup with user %s\\%s failed.\n",
				ipc_domain, ipc_username ));
		}
	}

	/* Fall back to anonymous connection, this might fail later */

	if (cli_session_setup(*cli, "", NULL, 0, NULL, 0, "")) {
		DEBUG(5, ("Connected anonymously\n"));
		cli_init_creds(*cli, "", "", "");
		goto session_setup_done;
	}

	result = cli_nt_error(*cli);

	if (NT_STATUS_IS_OK(result))
		result = NT_STATUS_UNSUCCESSFUL;

	/* We can't session setup */

	goto done;

 session_setup_done:

	if (!cli_send_tconX(*cli, "IPC$", "IPC", "", 0)) {

		result = cli_nt_error(*cli);

		DEBUG(1,("failed tcon_X with %s\n", nt_errstr(result)));

		if (NT_STATUS_IS_OK(result))
			result = NT_STATUS_UNSUCCESSFUL;

		cli_shutdown(*cli);
		goto done;
	}

	secrets_named_mutex_release(controller);
	got_mutex = False;
	*retry = False;

	/* set the domain if empty; needed for schannel connections */
	if ( !*(*cli)->domain ) {
		fstrcpy( (*cli)->domain, domain->name );
	}

	result = NT_STATUS_OK;
	add_failed_connection = False;

 done:
	if (got_mutex) {
		secrets_named_mutex_release(controller);
	}

	SAFE_FREE(machine_account);
	SAFE_FREE(machine_password);
	SAFE_FREE(machine_krb5_principal);
	SAFE_FREE(ipc_username);
	SAFE_FREE(ipc_domain);
	SAFE_FREE(ipc_password);

	if (add_failed_connection) {
		add_failed_connection_entry(domain->name, controller, result);
	}

	return result;
}

struct dc_name_ip {
	fstring name;
	struct in_addr ip;
};

static BOOL add_one_dc_unique(TALLOC_CTX *mem_ctx, const char *domain_name,
			      const char *dcname, struct in_addr ip,
			      struct dc_name_ip **dcs, int *num)
{
	if (!NT_STATUS_IS_OK(check_negative_conn_cache(domain_name, dcname))) {
		DEBUG(10, ("DC %s was in the negative conn cache\n", dcname));
		return False;
	}

	*dcs = TALLOC_REALLOC_ARRAY(mem_ctx, *dcs, struct dc_name_ip, (*num)+1);

	if (*dcs == NULL)
		return False;

	fstrcpy((*dcs)[*num].name, dcname);
	(*dcs)[*num].ip = ip;
	*num += 1;
	return True;
}

static BOOL add_sockaddr_to_array(TALLOC_CTX *mem_ctx,
				  struct in_addr ip, uint16 port,
				  struct sockaddr_in **addrs, int *num)
{
	*addrs = TALLOC_REALLOC_ARRAY(mem_ctx, *addrs, struct sockaddr_in, (*num)+1);

	if (*addrs == NULL)
		return False;

	(*addrs)[*num].sin_family = PF_INET;
	putip((char *)&((*addrs)[*num].sin_addr), (char *)&ip);
	(*addrs)[*num].sin_port = htons(port);

	*num += 1;
	return True;
}

static void mailslot_name(struct in_addr dc_ip, fstring name)
{
	fstr_sprintf(name, "\\MAILSLOT\\NET\\GETDC%X", dc_ip.s_addr);
}

static BOOL send_getdc_request(struct in_addr dc_ip,
			       const char *domain_name,
			       const DOM_SID *sid)
{
	pstring outbuf;
	char *p;
	fstring my_acct_name;
	fstring my_mailslot;

	mailslot_name(dc_ip, my_mailslot);

	memset(outbuf, '\0', sizeof(outbuf));

	p = outbuf;

	SCVAL(p, 0, SAMLOGON);
	p++;

	SCVAL(p, 0, 0); /* Count pointer ... */
	p++;