path: root/source3/smbd/service.c

/* 
   Unix SMB/CIFS implementation.
   service (connection) opening and closing
   Copyright (C) Andrew Tridgell 1992-1998

   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 "system/filesys.h"
#include "system/passwd.h" /* uid_wrapper */
#include "../lib/tsocket/tsocket.h"
#include "smbd/smbd.h"
#include "smbd/globals.h"
#include "../librpc/gen_ndr/netlogon.h"
#include "../libcli/security/security.h"
#include "printing/pcap.h"
#include "passdb/lookup_sid.h"
#include "auth.h"
#include "../auth/auth_util.h"
#include "lib/param/loadparm.h"
#include "messages.h"
#include "lib/afs/afs_funcs.h"
#include "lib/util_path.h"

static bool canonicalize_connect_path(connection_struct *conn)
{
	bool ret;
	struct smb_filename con_fname = { .base_name = conn->connectpath };
	struct smb_filename *resolved_fname = SMB_VFS_REALPATH(conn, talloc_tos(),
						&con_fname);
	if (resolved_fname == NULL) {
		return false;
	}
	ret = set_conn_connectpath(conn,resolved_fname->base_name);
	TALLOC_FREE(resolved_fname);
	return ret;
}

/****************************************************************************
 Ensure when setting connectpath it is a canonicalized (no ./ // or ../)
 absolute path stating in / and not ending in /.
****************************************************************************/

bool set_conn_connectpath(connection_struct *conn, const char *connectpath)
{
	char *destname;

	if (connectpath == NULL || connectpath[0] == '\0') {
		return false;
	}

	destname = canonicalize_absolute_path(conn, connectpath);
	if (destname == NULL) {
		return false;
	}

	DBG_DEBUG("service %s, connectpath = %s\n",
		  lp_const_servicename(SNUM(conn)), destname);

	talloc_free(conn->connectpath);
	conn->connectpath = destname;
	/*
	 * Ensure conn->cwd_fsp->fsp_name is initialized.
	 * start as conn->connectpath.
	 */
	TALLOC_FREE(conn->cwd_fsp->fsp_name);
	conn->cwd_fsp->fsp_name = synthetic_smb_fname(conn,
				conn->connectpath,
				NULL,
				NULL,
				0);
	if (conn->cwd_fsp->fsp_name == NULL) {
		return false;
	}
	return true;
}

/****************************************************************************
 Load parameters specific to a connection/service.
****************************************************************************/

void set_current_case_sensitive(connection_struct *conn, uint16_t flags)
{
	int snum;
	enum remote_arch_types ra_type;

	SMB_ASSERT(conn != NULL);

	snum = SNUM(conn);

	if ((conn == last_conn) && (last_flags == flags)) {
		return;
	}

	last_conn = conn;
	last_flags = flags;

	/*
	 * Obey the client case sensitivity requests - only for clients that
	 * support it. */
	switch (lp_case_sensitive(snum)) {
	case Auto:
		/*
		 * We need this uglyness due to DOS/Win9x clients that lie
		 * about case insensitivity. */
		ra_type = get_remote_arch();
		if (conn->sconn->using_smb2) {
			conn->case_sensitive = false;
		} else if ((ra_type != RA_SAMBA) && (ra_type != RA_CIFSFS)) {
			/*
			 * Client can't support per-packet case sensitive
			 * pathnames. */
			conn->case_sensitive = false;
		} else {
			conn->case_sensitive =
					!(flags & FLAG_CASELESS_PATHNAMES);
		}
	break;
	case True:
		conn->case_sensitive = true;
		break;
	default:
		conn->case_sensitive = false;
		break;
	}
	return;
}

bool chdir_current_service(connection_struct *conn)
{
	const struct smb_filename connectpath_fname = {
		.base_name = conn->connectpath,
	};
	const struct smb_filename origpath_fname = {
		.base_name = conn->origpath,
	};
	int ret;

	conn->lastused_count++;

	ret = vfs_ChDir(conn, &connectpath_fname);
	if (ret != 0) {
		int saved_errno = errno;

		if (saved_errno == EACCES) {
			char *str = utok_string(
				talloc_tos(),
				conn->session_info->unix_token);
			DBG_WARNING("vfs_ChDir(%s) got "
				    "permission denied, current "
				    "token: %s\n",
				    conn->connectpath, str);
			TALLOC_FREE(str);
		} else {
			DBG_ERR("vfs_ChDir(%s) failed: "
				"%s!\n",
				conn->connectpath,
				strerror(saved_errno));
		}
		return false;
	}

	ret = vfs_ChDir(conn, &origpath_fname);
	if (ret != 0) {
		int saved_errno = errno;

		if (saved_errno == EACCES) {
			char *str = utok_string(
				talloc_tos(),
				conn->session_info->unix_token);
			DBG_WARNING("vfs_ChDir(%s) got "
				    "permission denied, current "
				    "token: %s\n",
				    conn->origpath, str);
			TALLOC_FREE(str);
		} else {
			DBG_ERR("vfs_ChDir(%s) failed: "
				"%s!\n",
				conn->origpath,
				strerror(saved_errno));
		}
		return false;
	}

	return true;
}

/****************************************************************************
 do some basic sainity checks on the share.  
 This function modifies dev, ecode.
****************************************************************************/

static NTSTATUS share_sanity_checks(const struct tsocket_address *remote_address,
				    const char *rhost,
				    int snum,
				    fstring dev)
{
	char *raddr;

	raddr = tsocket_address_inet_addr_string(remote_address,
						 talloc_tos());
	if (raddr == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	if (!lp_snum_ok(snum) ||
	    !allow_access(lp_hosts_deny(snum), lp_hosts_allow(snum),
			  rhost, raddr)) {
		return NT_STATUS_ACCESS_DENIED;
	}

	if (dev[0] == '?' || !dev[0]) {
		if (lp_printable(snum)) {
			fstrcpy(dev,"LPT1:");
		} else if (strequal(lp_fstype(snum), "IPC")) {
			fstrcpy(dev, "IPC");
		} else {
			fstrcpy(dev,"A:");
		}
	}

	if (!strupper_m(dev)) {
		DEBUG(2,("strupper_m %s failed\n", dev));
		return NT_STATUS_INVALID_PARAMETER;
	}

	if (lp_printable(snum)) {
		if (!strequal(dev, "LPT1:")) {
			return NT_STATUS_BAD_DEVICE_TYPE;
		}
	} else if (strequal(lp_fstype(snum), "IPC")) {
		if (!strequal(dev, "IPC")) {
			return NT_STATUS_BAD_DEVICE_TYPE;
		}
	} else if (!strequal(dev, "A:")) {
		return NT_STATUS_BAD_DEVICE_TYPE;
	}

	/* Behave as a printer if we are supposed to */
	if (lp_printable(snum) && (strcmp(dev, "A:") == 0)) {
		fstrcpy(dev, "LPT1:");
	}

	return NT_STATUS_OK;
}

/*
 * Go through lookup_name etc to find the force'd group.  
 *
 * Create a new token from src_token, replacing the primary group sid with the
 * one found.
 */

static NTSTATUS find_forced_group(bool force_user,
				  int snum, const char *username,
				  struct dom_sid *pgroup_sid,
				  gid_t *pgid)
{
	NTSTATUS result = NT_STATUS_NO_SUCH_GROUP;
	TALLOC_CTX *frame = talloc_stackframe();
	struct dom_sid group_sid;
	enum lsa_SidType type;
	char *groupname;
	bool user_must_be_member = False;
	gid_t gid;

	groupname = lp_force_group(talloc_tos(), snum);
	if (groupname == NULL) {
		DEBUG(1, ("talloc_strdup failed\n"));
		result = NT_STATUS_NO_MEMORY;
		goto done;
	}

	if (groupname[0] == '+') {
		user_must_be_member = True;
		groupname += 1;
	}

	groupname = talloc_string_sub(talloc_tos(), groupname,
				      "%S", lp_const_servicename(snum));
	if (groupname == NULL) {
		DEBUG(1, ("talloc_string_sub failed\n"));
		result = NT_STATUS_NO_MEMORY;
		goto done;
	}

	if (!lookup_name_smbconf(talloc_tos(), groupname,
			 LOOKUP_NAME_ALL|LOOKUP_NAME_GROUP,
			 NULL, NULL, &group_sid, &type)) {
		DEBUG(10, ("lookup_name_smbconf(%s) failed\n",
			   groupname));
		goto done;
	}

	if ((type != SID_NAME_DOM_GRP) && (type != SID_NAME_ALIAS) &&
	    (type != SID_NAME_WKN_GRP)) {
		DEBUG(10, ("%s is a %s, not a group\n", groupname,
			   sid_type_lookup(type)));
		goto done;
	}

	if (!sid_to_gid(&group_sid, &gid)) {
		struct dom_sid_buf buf;
		DEBUG(10, ("sid_to_gid(%s) for %s failed\n",
			   dom_sid_str_buf(&group_sid, &buf), groupname));
		goto done;
	}

	/*
	 * If the user has been forced and the forced group starts with a '+',
	 * then we only set the group to be the forced group if the forced
	 * user is a member of that group.  Otherwise, the meaning of the '+'
	 * would be ignored.
	 */

	if (force_user && user_must_be_member) {
		if (user_in_group_sid(username, &group_sid)) {
			sid_copy(pgroup_sid, &group_sid);
			*pgid = gid;
			DEBUG(3,("Forced group %s for member %s\n",
				 groupname, username));
		} else {
			DEBUG(0,("find_forced_group: forced user %s is not a member "
				"of forced group %s. Disallowing access.\n",
				username, groupname ));
			result = NT_STATUS_MEMBER_NOT_IN_GROUP;
			goto done;
		}
	} else {
		sid_copy(pgroup_sid, &group_sid);
		*pgid = gid;
		DEBUG(3,("Forced group %s\n", groupname));
	}

	result = NT_STATUS_OK;
 done:
	TALLOC_FREE(frame);
	return result;
}

/****************************************************************************
  Create an auth_session_info structure for a connection_struct
****************************************************************************/

static NTSTATUS create_connection_session_info(struct smbd_server_connection *sconn,
					      TALLOC_CTX *mem_ctx, int snum,
                                              struct auth_session_info *session_info,
                                              struct auth_session_info **presult)
{
	struct auth_session_info *result;

        if (lp_guest_only(snum)) {
                return make_session_info_guest(mem_ctx, presult);
        }

	/*
	 * This is the normal security != share case where we have a
	 * valid vuid from the session setup.                 */

	if (security_session_user_level(session_info, NULL) < SECURITY_USER) {
		if (!lp_guest_ok(snum)) {
			DBG_WARNING("guest user (from session setup) "
				  "not permitted to access this share "
				  "(%s)\n", lp_const_servicename(snum));
			return NT_STATUS_ACCESS_DENIED;
		}
	} else {
		if (!user_ok_token(session_info->unix_info->unix_name,
				   session_info->info->domain_name,
				   session_info->security_token, snum)) {
			DBG_WARNING("user '%s' (from session setup) not "
				  "permitted to access this share "
				  "(%s)\n",
				  session_info->unix_info->unix_name,
				  lp_const_servicename(snum));
			return NT_STATUS_ACCESS_DENIED;
		}
	}

	result = copy_session_info(mem_ctx, session_info);
	if (result == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	*presult = result;
	return NT_STATUS_OK;
}

/****************************************************************************
  Set relevant user and group settings corresponding to force user/group
  configuration for the given snum.
****************************************************************************/

NTSTATUS set_conn_force_user_group(connection_struct *conn, int snum)
{
	NTSTATUS status;

	if (*lp_force_user(talloc_tos(), snum)) {

		/*
		 * Replace conn->session_info with a completely faked up one
		 * from the username we are forced into :-)
		 */

		char *fuser;
		char *sanitized_username;
		struct auth_session_info *forced_serverinfo;
		bool guest;

		fuser = talloc_string_sub(conn, lp_force_user(talloc_tos(), snum), "%S",
					  lp_const_servicename(snum));
		if (fuser == NULL) {
			return NT_STATUS_NO_MEMORY;
		}

		guest = security_session_user_level(conn->session_info, NULL) < SECURITY_USER;

		status = make_session_info_from_username(
			conn, fuser,
			guest,
			&forced_serverinfo);
		if (!NT_STATUS_IS_OK(status)) {
			return status;
		}

		/* We don't want to replace the original sanitized_username
		   as it is the original user given in the connect attempt.
		   This is used in '%U' substitutions. */
		sanitized_username = discard_const_p(char,
			forced_serverinfo->unix_info->sanitized_username);
		TALLOC_FREE(sanitized_username);
		forced_serverinfo->unix_info->sanitized_username =
			talloc_move(forced_serverinfo->unix_info,
				&conn->session_info->unix_info->sanitized_username);

		TALLOC_FREE(conn->session_info);
		conn->session_info = forced_serverinfo;

		conn->force_user = true;
		DEBUG(3,("Forced user %s\n", fuser));
	}

	/*
	 * If force group is true, then override
	 * any groupid stored for the connecting user.
	 */

	if (*lp_force_group(talloc_tos(), snum)) {

		status = find_forced_group(
			conn->force_user, snum, conn->session_info->unix_info->unix_name,
			&conn->session_info->security_token->sids[1],
			&conn->session_info->unix_token->gid);

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

		/*
		 * We need to cache this gid, to use within
		 * change_to_user() separately from the conn->session_info
		 * struct. We only use conn->session_info directly if
		 * "force_user" was set.
		 */
		conn->force_group_gid = conn->session_info->unix_token->gid;
	}

	return NT_STATUS_OK;
}

static NTSTATUS notify_init_sconn(struct smbd_server_connection *sconn)
{
	NTSTATUS status;

	if (sconn->notify_ctx != NULL) {
		return NT_STATUS_OK;
	}

	sconn->notify_ctx = notify_init(sconn, sconn->msg_ctx,
					sconn, notify_callback);
	if (sconn->notify_ctx == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	status = messaging_register(sconn->msg_ctx, sconn,
				    MSG_SMB_NOTIFY_CANCEL_DELETED,
				    smbd_notify_cancel_deleted);
	if (!NT_STATUS_IS_OK(status)) {
		DBG_DEBUG("messaging_register failed: %s\n",
			  nt_errstr(status));
		TALLOC_FREE(sconn->notify_ctx);
		return status;
	}

	status = messaging_register(sconn->msg_ctx, sconn,
				    MSG_SMB_NOTIFY_STARTED,
				    smbd_notifyd_restarted);
	if (!NT_STATUS_IS_OK(status)) {
		DBG_DEBUG("messaging_register failed: %s\n",
			  nt_errstr(status));
		messaging_deregister(sconn->msg_ctx,
				     MSG_SMB_NOTIFY_CANCEL_DELETED, sconn);
		TALLOC_FREE(sconn->notify_ctx);
		return status;
	}

	return NT_STATUS_OK;
}

/****************************************************************************
  Make a connection, given the snum to connect to, and the vuser of the
  connecting user if appropriate.
****************************************************************************/

static NTSTATUS make_connection_snum(struct smbXsrv_connection *xconn,
					connection_struct *conn,
					int snum, struct user_struct *vuser,
					const char *pdev)
{
	struct smbd_server_connection *sconn = xconn->client->sconn;
	struct smb_filename *smb_fname_cpath = NULL;
	fstring dev;
	int ret;
	bool on_err_call_dis_hook = false;
	uid_t effuid;
	gid_t effgid;
	NTSTATUS status;

	fstrcpy(dev, pdev);

	status = share_sanity_checks(sconn->remote_address,
				       sconn->remote_hostname,
				       snum,
				       dev);
	if (NT_STATUS_IS_ERR(status)) {
		goto err_root_exit;
	}

	conn->params->service = snum;

	status = create_connection_session_info(sconn,
		conn, snum, vuser->session_info,
		&conn->session_info);

	if (!NT_STATUS_IS_OK(status)) {
		DEBUG(1, ("create_connection_session_info failed: %s\n",
			  nt_errstr(status)));
		goto err_root_exit;
	}

	if (lp_guest_only(snum)) {
		conn->force_user = true;
	}

	conn->num_files_open = 0;
	conn->lastused = conn->lastused_count = time(NULL);
	conn->printer = (strncmp(dev,"LPT",3) == 0);
	conn->ipc = ( (strncmp(dev,"IPC",3) == 0) ||
		      ( lp_enable_asu_support() && strequal(dev,"ADMIN$")) );

	/* Case options for the share. */
	if (lp_case_sensitive(snum) == Auto) {
		/* We will be setting this per packet. Set to be case
		 * insensitive for now. */
		conn->case_sensitive = False;
	} else {
		conn->case_sensitive = (bool)lp_case_sensitive(snum);
	}

	conn->case_preserve = lp_preserve_case(snum);
	conn->short_case_preserve = lp_short_preserve_case(snum);

	conn->encrypt_level = lp_smb_encrypt(snum);
	if (conn->encrypt_level > SMB_SIGNING_OFF) {
		if (lp_smb_encrypt(-1) == SMB_SIGNING_OFF) {
			if (conn->encrypt_level == SMB_SIGNING_REQUIRED) {
				DBG_ERR("Service [%s] requires encryption, but "
					"it is disabled globally!\n",
					lp_const_servicename(snum));
				status = NT_STATUS_ACCESS_DENIED;
				goto err_root_exit;
			}
			conn->encrypt_level = SMB_SIGNING_OFF;
		}
	}

	conn->veto_list = NULL;
	conn->hide_list = NULL;
	conn->veto_oplock_list = NULL;
	conn->aio_write_behind_list = NULL;

	conn->read_only = lp_read_only(SNUM(conn));

	status = set_conn_force_user_group(conn, snum);
	if (!NT_STATUS_IS_OK(status)) {
		goto err_root_exit;
	}

	conn->vuid = vuser->vuid;

	{
		char *s = talloc_sub_advanced(talloc_tos(),
					lp_const_servicename(SNUM(conn)),
					conn->session_info->unix_info->unix_name,
					conn->connectpath,
					conn->session_info->unix_token->gid,
					conn->session_info->unix_info->sanitized_username,
					conn->session_info->info->domain_name,
					lp_path(talloc_tos(), snum));
		if (!s) {
			status = NT_STATUS_NO_MEMORY;
			goto err_root_exit;
		}

		if (!set_conn_connectpath(conn,s)) {
			TALLOC_FREE(s);
			status = NT_STATUS_NO_MEMORY;
			goto err_root_exit;
		}
		DBG_NOTICE("Connect path is '%s' for service [%s]\n", s,
			   lp_const_servicename(snum));
		TALLOC_FREE(s);
	}

	/*
	 * Set up the share security descriptor.
	 * NOTE - we use the *INCOMING USER* session_info
	 * here, as does (indirectly) change_to_user(),
	 * which can be called on any incoming packet.
	 * This way we set up the share access based
	 * on the authenticated user, not the forced
	 * user. See bug:
	 *
	 * https://bugzilla.samba.org/show_bug.cgi?id=9878
	 */

	status = check_user_share_access(conn,
					vuser->session_info,
					&conn->share_access,
					&conn->read_only);
	if (!NT_STATUS_IS_OK(status)) {
		goto err_root_exit;
	}

	/* Initialise VFS function pointers */

	if (!smbd_vfs_init(conn)) {
		DBG_ERR("vfs_init failed for service %s\n",
			lp_const_servicename(snum));
		status = NT_STATUS_BAD_NETWORK_NAME;
		goto err_root_exit;
	}

/* ROOT Activities: */
	/* explicitly check widelinks here so that we can correctly warn
	 * in the logs. */
	widelinks_warning(snum);

	/*
	 * Enforce the max connections parameter.
	 */

	if ((lp_max_connections(snum) > 0)
	    && (count_current_connections(lp_const_servicename(SNUM(conn)), true) >=
		lp_max_connections(snum))) {

		DBG_WARNING("Max connections (%d) exceeded for %s\n",
			  lp_max_connections(snum),
			  lp_const_servicename(snum));
		status = NT_STATUS_INSUFFICIENT_RESOURCES;
		goto err_root_exit;
	}

	/* Invoke VFS make connection hook - this must be the first
	   filesystem operation that we do. */

	if (SMB_VFS_CONNECT(conn, lp_const_servicename(snum),
			    conn->session_info->unix_info->unix_name) < 0) {
		DBG_WARNING("SMB_VFS_CONNECT for service '%s' at '%s' failed: %s\n",
			    lp_const_servicename(snum), conn->connectpath,
			    strerror(errno));
		status = NT_STATUS_UNSUCCESSFUL;
		goto err_root_exit;
	}

	/* Any error exit after here needs to call the disconnect hook. */
	on_err_call_dis_hook = true;

	if ((!conn->printer) && (!conn->ipc) &&
	    lp_change_notify()) {

		status = notify_init_sconn(sconn);
		if (!NT_STATUS_IS_OK(status)) {
			goto err_root_exit;
		}
	}

	if (lp_kernel_oplocks(snum)) {
		init_kernel_oplocks(conn->sconn);
	}

	/*
	 * Fix compatibility issue pointed out by Volker.
	 * We pass the conn->connectpath to the preexec
	 * scripts as a parameter, so attempt to canonicalize
	 * it here before calling the preexec scripts.
	 * We ignore errors here, as it is possible that
	 * the conn->connectpath doesn't exist yet and
	 * the preexec scripts will create them.
	 */

	(void)canonicalize_connect_path(conn);

	/* Preexecs are done here as they might make the dir we are to ChDir
	 * to below */
	/* execute any "root preexec = " line */
	if (*lp_root_preexec(talloc_tos(), snum)) {
		char *cmd = talloc_sub_advanced(talloc_tos(),
					lp_const_servicename(SNUM(conn)),
					conn->session_info->unix_info->unix_name,
					conn->connectpath,
					conn->session_info->unix_token->gid,
					conn->session_info->unix_info->sanitized_username,
					conn->session_info->info->domain_name,
					lp_root_preexec(talloc_tos(), snum));
		DEBUG(5,("cmd=%s\n",cmd));
		ret = smbrun(cmd, NULL, NULL);
		TALLOC_FREE(cmd);
		if (ret != 0 && lp_root_preexec_close(snum)) {
			DEBUG(1,("root preexec gave %d - failing "
				 "connection\n", ret));
			status = NT_STATUS_ACCESS_DENIED;
			goto err_root_exit;
		}
	}

/* USER Activites: */
	if (!change_to_user_and_service(conn, conn->vuid)) {
		/* No point continuing if they fail the basic checks */
		DEBUG(0,("Can't become connected user!\n"));
		status = NT_STATUS_LOGON_FAILURE;
		goto err_root_exit;
	}

	effuid = geteuid();
	effgid = getegid();

	/* Remember that a different vuid can connect later without these
	 * checks... */

	/* Preexecs are done here as they might make the dir we are to ChDir
	 * to below */

	/* execute any "preexec = " line */
	if (*lp_preexec(talloc_tos(), snum)) {
		char *cmd = talloc_sub_advanced(talloc_tos(),
					lp_const_servicename(SNUM(conn)),
					conn->session_info->unix_info->unix_name,
					conn->connectpath,
					conn->session_info->unix_token->gid,
					conn->session_info->unix_info->sanitized_username,
					conn->session_info->info->domain_name,
					lp_preexec(talloc_tos(), snum));
		ret = smbrun(cmd, NULL, NULL);
		TALLOC_FREE(cmd);
		if (ret != 0 && lp_preexec_close(snum)) {
			DEBUG(1,("preexec gave %d - failing connection\n",
				 ret));
			status = NT_STATUS_ACCESS_DENIED;
			goto err_root_exit;
		}
	}

#ifdef WITH_FAKE_KASERVER
	if (lp_afs_share(snum)) {
		afs_login(conn);
	}
#endif

	/*
	 * we've finished with the user stuff - go back to root
	 * so the SMB_VFS_STAT call will only fail on path errors,
	 * not permission problems.
	 */
	change_to_root_user();
/* ROOT Activites: */

	/*
	 * If widelinks are disallowed we need to canonicalise the connect
	 * path here to ensure we don't have any symlinks in the
	 * connectpath. We will be checking all paths on this connection are
	 * below this directory. We must do this after the VFS init as we
	 * depend on the realpath() pointer in the vfs table. JRA.
	 */
	if (!lp_widelinks(snum)) {
		if (!canonicalize_connect_path(conn)) {
			DBG_ERR("canonicalize_connect_path failed "
			"for service %s, path %s\n",
				lp_const_servicename(snum),
				conn->connectpath);
			status = NT_STATUS_BAD_NETWORK_NAME;
			goto err_root_exit;
		}
	}

	/* Add veto/hide lists */
	if (!IS_IPC(conn) && !IS_PRINT(conn)) {
		set_namearray( &conn->veto_list,
			       lp_veto_files(talloc_tos(), snum));
		set_namearray( &conn->hide_list,
			       lp_hide_files(talloc_tos(), snum));
		set_namearray( &conn->veto_oplock_list,
			       lp_veto_oplock_files(talloc_tos(), snum));
		set_namearray( &conn->aio_write_behind_list,
				lp_aio_write_behind(talloc_tos(), snum));
	}
	smb_fname_cpath = synthetic_smb_fname(talloc_tos(),
					conn->connectpath,
					NULL,
					NULL,
					0);
	if (smb_fname_cpath == NULL) {
		status = NT_STATUS_NO_MEMORY;
		goto err_root_exit;
	}

	/* win2000 does not check the permissions on the directory
	   during the tree connect, instead relying on permission
	   check during individual operations. To match this behaviour
	   I have disabled this chdir check (tridge) */
	/* the alternative is just to check the directory exists */

	if ((ret = SMB_VFS_STAT(conn, smb_fname_cpath)) != 0 ||
	    !S_ISDIR(smb_fname_cpath->st.st_ex_mode)) {
		if (ret == 0 && !S_ISDIR(smb_fname_cpath->st.st_ex_mode)) {
			DBG_ERR("'%s' is not a directory, when connecting to "
				 "[%s]\n", conn->connectpath,
				 lp_const_servicename(snum));
		} else {
			DBG_ERR("'%s' does not exist or permission denied "
				 "when connecting to [%s] Error was %s\n",
				 conn->connectpath,
				 lp_const_servicename(snum),
				 strerror(errno));
		}
		status = NT_STATUS_BAD_NETWORK_NAME;
		goto err_root_exit;
	}
	conn->base_share_dev = smb_fname_cpath->st.st_ex_dev;

	talloc_free(conn->origpath);
	conn->origpath = talloc_strdup(conn, conn->connectpath);

	/* Figure out the characteristics of the underlying filesystem. This
	 * assumes that all the filesystem mounted within a share path have
	 * the same characteristics, which is likely but not guaranteed.
	 */

	conn->fs_capabilities = SMB_VFS_FS_CAPABILITIES(conn, &conn->ts_res);

	/*
	 * Print out the 'connected as' stuff here as we need
	 * to know the effective uid and gid we will be using
	 * (at least initially).
	 */

	if( DEBUGLVL( IS_IPC(conn) ? 3 : 2 ) ) {
		dbgtext( "%s (%s) ", get_remote_machine_name(),
			 tsocket_address_string(conn->sconn->remote_address,
						talloc_tos()) );
		dbgtext( "%s", srv_is_signing_active(xconn) ? "signed " : "");
		dbgtext( "connect to service %s ",
			 lp_const_servicename(snum) );
		dbgtext( "initially as user %s ",
			 conn->session_info->unix_info->unix_name );
		dbgtext( "(uid=%d, gid=%d) ", (int)effuid, (int)effgid );
		dbgtext( "(pid %d)\n", (int)getpid() );
	}

	conn->tcon_done = true;
	return NT_STATUS_OK;

  err_root_exit:

	TALLOC_FREE(smb_fname_cpath);
	/* We must exit this function as root. */
	if (geteuid() != 0) {
		change_to_root_user();
	}
	if (on_err_call_dis_hook) {
		/* Call VFS disconnect hook */
		SMB_VFS_DISCONNECT(conn);
	}
	return status;
}

/****************************************************************************
 Make a connection to a service from SMB1. Internal interface.
****************************************************************************/

static connection_struct *make_connection_smb1(struct smb_request *req,
					NTTIME now,
					int snum, struct user_struct *vuser,
					const char *pdev,
					NTSTATUS *pstatus)
{
	struct smbXsrv_tcon *tcon;
	NTSTATUS status;
	struct connection_struct *conn;

	status = smb1srv_tcon_create(req->xconn, now, &tcon);
	if (!NT_STATUS_IS_OK(status)) {
		DEBUG(0,("make_connection_smb1: Couldn't find free tcon %s.\n",
			 nt_errstr(status)));
		*pstatus = status;
		return NULL;
	}

	conn = conn_new(req->sconn);
	if (!conn) {
		TALLOC_FREE(tcon);

		DEBUG(0,("make_connection_smb1: Couldn't find free connection.\n"));
		*pstatus = NT_STATUS_INSUFFICIENT_RESOURCES;
		return NULL;
	}

	conn->cnum = tcon->global->tcon_wire_id;
	conn->tcon = tcon;

	*pstatus = make_connection_snum(req->xconn,
					conn,
					snum,
					vuser,
					pdev);
	if (!NT_STATUS_IS_OK(*pstatus)) {
		conn_free(conn);
		TALLOC_FREE(tcon);
		return NULL;
	}

	tcon->global->share_name = lp_servicename(tcon->global, SNUM(conn));
	if (tcon->global->share_name == NULL) {
		conn_free(conn);
		TALLOC_FREE(tcon);
		*pstatus = NT_STATUS_NO_MEMORY;
		return NULL;
	}
	tcon->global->session_global_id =
		vuser->session->global->session_global_id;

	tcon->compat = talloc_move(tcon, &conn);
	tcon->status = NT_STATUS_OK;

	*pstatus = smbXsrv_tcon_update(tcon);
	if (!NT_STATUS_IS_OK(*pstatus)) {
		TALLOC_FREE(tcon);
		return NULL;
	}

	return tcon->compat;
}

/****************************************************************************
 Make a connection to a service from SMB2. External SMB2 interface.
 We must set cnum before claiming connection.
****************************************************************************/

connection_struct *make_connection_smb2(struct smbd_smb2_request *req,
					struct smbXsrv_tcon *tcon,
					int snum,
					struct user_struct *vuser,
					const char *pdev,
					NTSTATUS *pstatus)
{
	struct smbd_server_connection *sconn = req->sconn;
	connection_struct *conn = conn_new(sconn);
	if (!conn) {
		DEBUG(0,("make_connection_smb2: Couldn't find free connection.\n"));
		*pstatus = NT_STATUS_INSUFFICIENT_RESOURCES;
		return NULL;
	}

	conn->cnum = tcon->global->tcon_wire_id;
	conn->tcon = tcon;

	*pstatus = make_connection_snum(req->xconn,
					conn,
					snum,
					vuser,
					pdev);
	if (!NT_STATUS_IS_OK(*pstatus)) {
		conn_free(conn);
		return NULL;
	}
	return conn;
}

/****************************************************************************
 Make a connection to a service. External SMB1 interface.
 *
 * @param service 
****************************************************************************/

connection_struct *make_connection(struct smb_request *req,
				   NTTIME now,
				   const char *service_in,
				   const char *pdev, uint64_t vuid,
				   NTSTATUS *status)
{
	struct smbd_server_connection *sconn = req->sconn;
	uid_t euid;
	struct user_struct *vuser = NULL;
	char *service = NULL;
	fstring dev;
	int snum = -1;

	fstrcpy(dev, pdev);

	/* This must ONLY BE CALLED AS ROOT. As it exits this function as
	 * root. */
	if (!non_root_mode() && (euid = geteuid()) != 0) {
		DEBUG(0,("make_connection: PANIC ERROR. Called as nonroot "
			 "(%u)\n", (unsigned int)euid ));
		smb_panic("make_connection: PANIC ERROR. Called as nonroot\n");
	}

	if (conn_num_open(sconn) > 2047) {
		*status = NT_STATUS_INSUFF_SERVER_RESOURCES;
		return NULL;
	}

	vuser = get_valid_user_struct(sconn, vuid);
	if (!vuser) {
		DEBUG(1,("make_connection: refusing to connect with "
			 "no session setup\n"));
		*status = NT_STATUS_ACCESS_DENIED;
		return NULL;
	}

	/* Logic to try and connect to the correct [homes] share, preferably
	   without too many getpwnam() lookups.  This is particulary nasty for
	   winbind usernames, where the share name isn't the same as unix
	   username.

	   The snum of the homes share is stored on the vuser at session setup
	   time.
	*/

	if (strequal(service_in,HOMES_NAME)) {
		if (vuser->homes_snum == -1) {
			DEBUG(2, ("[homes] share not available for "
				  "this user because it was not found "
				  "or created at session setup "
				  "time\n"));
			*status = NT_STATUS_BAD_NETWORK_NAME;
			return NULL;
		}
		DEBUG(5, ("making a connection to [homes] service "
			  "created at session setup time\n"));
		return make_connection_smb1(req, now,
					    vuser->homes_snum,
					    vuser,
					    dev, status);
	} else if ((vuser->homes_snum != -1)
		   && strequal(service_in,
			       lp_const_servicename(vuser->homes_snum))) {
		DEBUG(5, ("making a connection to 'homes' service [%s] "
			  "created at session setup time\n", service_in));
		return make_connection_smb1(req, now,
					    vuser->homes_snum,
					    vuser,
					    dev, status);
	}

	service = talloc_strdup(talloc_tos(), service_in);
	if (!service) {
		*status = NT_STATUS_NO_MEMORY;
		return NULL;
	}

	if (!strlower_m(service)) {
		DEBUG(2, ("strlower_m %s failed\n", service));
		*status = NT_STATUS_INVALID_PARAMETER;
		return NULL;
	}

	snum = find_service(talloc_tos(), service, &service);
	if (!service) {
		*status = NT_STATUS_NO_MEMORY;
		return NULL;
	}

	if (snum < 0) {
		if (strequal(service,"IPC$") ||
		    (lp_enable_asu_support() && strequal(service,"ADMIN$"))) {
			DEBUG(3,("refusing IPC connection to %s\n", service));
			*status = NT_STATUS_ACCESS_DENIED;
			return NULL;
		}

		DEBUG(3,("%s (%s) couldn't find service %s\n",
			get_remote_machine_name(),
			tsocket_address_string(
				sconn->remote_address, talloc_tos()),
			service));
		*status = NT_STATUS_BAD_NETWORK_NAME;
		return NULL;
	}

	/* Handle non-Dfs clients attempting connections to msdfs proxy */
	if (lp_host_msdfs() && (*lp_msdfs_proxy(talloc_tos(), snum) != '\0'))  {
		DEBUG(3, ("refusing connection to dfs proxy share '%s' "
			  "(pointing to %s)\n", 
			service, lp_msdfs_proxy(talloc_tos(), snum)));
		*status = NT_STATUS_BAD_NETWORK_NAME;
		return NULL;
	}

	DEBUG(5, ("making a connection to 'normal' service %s\n", service));

	return make_connection_smb1(req, now, snum, vuser,
				    dev, status);
}

/****************************************************************************
 Close a cnum.
****************************************************************************/

void close_cnum(connection_struct *conn, uint64_t vuid)
{
	char rootpath[2] = { '/', '\0'};
	struct smb_filename root_fname = { .base_name = rootpath };

	file_close_conn(conn);

	change_to_root_user();

	DEBUG(IS_IPC(conn)?3:2, ("%s (%s) closed connection to service %s\n",
				 get_remote_machine_name(),
				 tsocket_address_string(conn->sconn->remote_address,
							talloc_tos()),
				 lp_const_servicename(SNUM(conn))));

	/* make sure we leave the directory available for unmount */
	vfs_ChDir(conn, &root_fname);

	/* Call VFS disconnect hook */
	SMB_VFS_DISCONNECT(conn);

	/* execute any "postexec = " line */
	if (*lp_postexec(talloc_tos(), SNUM(conn)) &&
	    change_to_user_and_service(conn, vuid))  {
		char *cmd = talloc_sub_advanced(talloc_tos(),
					lp_const_servicename(SNUM(conn)),
					conn->session_info->unix_info->unix_name,
					conn->connectpath,
					conn->session_info->unix_token->gid,
					conn->session_info->unix_info->sanitized_username,
					conn->session_info->info->domain_name,
					lp_postexec(talloc_tos(), SNUM(conn)));
		smbrun(cmd, NULL, NULL);
		TALLOC_FREE(cmd);
		change_to_root_user();
	}

	change_to_root_user();
	/* execute any "root postexec = " line */
	if (*lp_root_postexec(talloc_tos(), SNUM(conn)))  {
		char *cmd = talloc_sub_advanced(talloc_tos(),
					lp_const_servicename(SNUM(conn)),
					conn->session_info->unix_info->unix_name,
					conn->connectpath,
					conn->session_info->unix_token->gid,
					conn->session_info->unix_info->sanitized_username,
					conn->session_info->info->domain_name,
					lp_root_postexec(talloc_tos(), SNUM(conn)));
		smbrun(cmd, NULL, NULL);
		TALLOC_FREE(cmd);
	}

	conn_free(conn);
}