cldap.c   [plain text]

/* 
   Samba Unix/Linux SMB client library 
   net ads cldap functions 
   Copyright (C) 2001 Andrew Tridgell (tridge@samba.org)
   Copyright (C) 2003 Jim McDonough (jmcd@us.ibm.com)

   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.  
*/

#include "includes.h"

/*
  These seem to be strings as described in RFC1035 4.1.4 and can be:

   - a sequence of labels ending in a zero octet
   - a pointer
   - a sequence of labels ending with a pointer

  A label is a byte where the first two bits must be zero and the remaining
  bits represent the length of the label followed by the label itself.
  Therefore, the length of a label is at max 64 bytes.  Under RFC1035, a
  sequence of labels cannot exceed 255 bytes.

  A pointer consists of a 14 bit offset from the beginning of the data.

  struct ptr {
    unsigned ident:2; // must be 11
    unsigned offset:14; // from the beginning of data
  };

  This is used as a method to compress the packet by eliminated duplicate
  domain components.  Since a UDP packet should probably be < 512 bytes and a
  DNS name can be up to 255 bytes, this actually makes a lot of sense.
*/
static unsigned pull_netlogon_string(char *ret, const char *ptr,
				     const char *data)
{
	char *pret = ret;
	int followed_ptr = 0;
	unsigned ret_len = 0;

	memset(pret, 0, MAX_DNS_LABEL);
	do {
		if ((*ptr & 0xc0) == 0xc0) {
			uint16 len;

			if (!followed_ptr) {
				ret_len += 2;
				followed_ptr = 1;
			}
			len = ((ptr[0] & 0x3f) << 8) | ptr[1];
			ptr = data + len;
		} else if (*ptr) {
			uint8 len = (uint8)*(ptr++);

			if ((pret - ret + len + 1) >= MAX_DNS_LABEL) {
				DEBUG(1,("DC returning too long DNS name\n"));
				return 0;
			}

			if (pret != ret) {
				*pret = '.';
				pret++;
			}
			memcpy(pret, ptr, len);
			pret += len;
			ptr += len;

			if (!followed_ptr) {
				ret_len += (len + 1);
			}
		}
	} while (*ptr);

	return followed_ptr ? ret_len : ret_len + 1;
}

/*
  do a cldap netlogon query
*/
static int send_cldap_netlogon(int sock, const char *domain, 
			       const char *hostname, unsigned ntversion)
{
	ASN1_DATA data;
	char ntver[4];
#ifdef CLDAP_USER_QUERY
	char aac[4];

	SIVAL(aac, 0, 0x00000180);
#endif
	SIVAL(ntver, 0, ntversion);

	memset(&data, 0, sizeof(data));

	asn1_push_tag(&data,ASN1_SEQUENCE(0));
	asn1_write_Integer(&data, 4);
	asn1_push_tag(&data, ASN1_APPLICATION(3));
	asn1_write_OctetString(&data, NULL, 0);
	asn1_write_enumerated(&data, 0);
	asn1_write_enumerated(&data, 0);
	asn1_write_Integer(&data, 0);
	asn1_write_Integer(&data, 0);
	asn1_write_BOOLEAN2(&data, False);
	asn1_push_tag(&data, ASN1_CONTEXT(0));

	if (domain) {
		asn1_push_tag(&data, ASN1_CONTEXT(3));
		asn1_write_OctetString(&data, "DnsDomain", 9);
		asn1_write_OctetString(&data, domain, strlen(domain));
		asn1_pop_tag(&data);
	}

	asn1_push_tag(&data, ASN1_CONTEXT(3));
	asn1_write_OctetString(&data, "Host", 4);
	asn1_write_OctetString(&data, hostname, strlen(hostname));
	asn1_pop_tag(&data);

#ifdef CLDAP_USER_QUERY
	asn1_push_tag(&data, ASN1_CONTEXT(3));
	asn1_write_OctetString(&data, "User", 4);
	asn1_write_OctetString(&data, "SAMBA$", 6);
	asn1_pop_tag(&data);

	asn1_push_tag(&data, ASN1_CONTEXT(3));
	asn1_write_OctetString(&data, "AAC", 4);
	asn1_write_OctetString(&data, aac, 4);
	asn1_pop_tag(&data);
#endif

	asn1_push_tag(&data, ASN1_CONTEXT(3));
	asn1_write_OctetString(&data, "NtVer", 5);
	asn1_write_OctetString(&data, ntver, 4);
	asn1_pop_tag(&data);

	asn1_pop_tag(&data);

	asn1_push_tag(&data,ASN1_SEQUENCE(0));
	asn1_write_OctetString(&data, "NetLogon", 8);
	asn1_pop_tag(&data);
	asn1_pop_tag(&data);
	asn1_pop_tag(&data);

	if (data.has_error) {
		DEBUG(2,("Failed to build cldap netlogon at offset %d\n", (int)data.ofs));
		asn1_free(&data);
		return -1;
	}

	if (write(sock, data.data, data.length) != (ssize_t)data.length) {
		DEBUG(2,("failed to send cldap query (%s)\n", strerror(errno)));
		asn1_free(&data);
		return -1;
	}

	asn1_free(&data);

	return 0;
}

static SIG_ATOMIC_T gotalarm;
                                                                                                                   
/***************************************************************
 Signal function to tell us we timed out.
****************************************************************/
                                                                                                                   
static void gotalarm_sig(void)
{
	gotalarm = 1;
}
                                                                                                                   
/*
  receive a cldap netlogon reply
*/
static int recv_cldap_netlogon(int sock, struct cldap_netlogon_reply *reply)
{
	int ret;
	ASN1_DATA data;
	DATA_BLOB blob = data_blob(NULL, 0);
	DATA_BLOB os1 = data_blob(NULL, 0);
	DATA_BLOB os2 = data_blob(NULL, 0);
	DATA_BLOB os3 = data_blob(NULL, 0);
	int i1;
	/* half the time of a regular ldap timeout, not less than 3 seconds. */
	unsigned int al_secs = MAX(3,lp_ldap_timeout()/2);
	char *p;

	blob = data_blob(NULL, 8192);
	if (blob.data == NULL) {
		DEBUG(1, ("data_blob failed\n"));
		errno = ENOMEM;
		return -1;
	}

	/* Setup timeout */
	gotalarm = 0;
	CatchSignal(SIGALRM, SIGNAL_CAST gotalarm_sig);
	alarm(al_secs);
	/* End setup timeout. */
 
	ret = read(sock, blob.data, blob.length);

	/* Teardown timeout. */
	CatchSignal(SIGALRM, SIGNAL_CAST SIG_IGN);
	alarm(0);

	if (ret <= 0) {
		DEBUG(1,("no reply received to cldap netlogon\n"));
		data_blob_free(&blob);
		return -1;
	}
	blob.length = ret;

	asn1_load(&data, blob);
	asn1_start_tag(&data, ASN1_SEQUENCE(0));
	asn1_read_Integer(&data, &i1);
	asn1_start_tag(&data, ASN1_APPLICATION(4));
	asn1_read_OctetString(&data, &os1);
	asn1_start_tag(&data, ASN1_SEQUENCE(0));
	asn1_start_tag(&data, ASN1_SEQUENCE(0));
	asn1_read_OctetString(&data, &os2);
	asn1_start_tag(&data, ASN1_SET);
	asn1_read_OctetString(&data, &os3);
	asn1_end_tag(&data);
	asn1_end_tag(&data);
	asn1_end_tag(&data);
	asn1_end_tag(&data);
	asn1_end_tag(&data);

	if (data.has_error) {
		data_blob_free(&blob);
		data_blob_free(&os1);
		data_blob_free(&os2);
		data_blob_free(&os3);
		asn1_free(&data);
		DEBUG(1,("Failed to parse cldap reply\n"));
		return -1;
	}

	p = (char *)os3.data;

	reply->type = IVAL(p, 0); p += 4;
	reply->flags = IVAL(p, 0); p += 4;

	memcpy(&reply->guid.info, p, UUID_FLAT_SIZE);
	p += UUID_FLAT_SIZE;

	p += pull_netlogon_string(reply->forest, p, (const char *)os3.data);
	p += pull_netlogon_string(reply->domain, p, (const char *)os3.data);
	p += pull_netlogon_string(reply->hostname, p, (const char *)os3.data);
	p += pull_netlogon_string(reply->netbios_domain, p, (const char *)os3.data);
	p += pull_netlogon_string(reply->netbios_hostname, p, (const char *)os3.data);
	p += pull_netlogon_string(reply->unk, p, (const char *)os3.data);

	if (reply->type == SAMLOGON_AD_R) {
		p += pull_netlogon_string(reply->user_name, p, (const char *)os3.data);
	} else {
		*reply->user_name = 0;
	}

	p += pull_netlogon_string(reply->server_site_name, p, (const char *)os3.data);
	p += pull_netlogon_string(reply->client_site_name, p, (const char *)os3.data);

	reply->version = IVAL(p, 0);
	reply->lmnt_token = SVAL(p, 4);
	reply->lm20_token = SVAL(p, 6);

	data_blob_free(&os1);
	data_blob_free(&os2);
	data_blob_free(&os3);
	data_blob_free(&blob);
	
	asn1_free(&data);

	return 0;
}

/*******************************************************************
  do a cldap netlogon query.  Always 389/udp
*******************************************************************/

BOOL ads_cldap_netlogon(const char *server, const char *realm,  struct cldap_netlogon_reply *reply)
{
	int sock;
	int ret;

	sock = open_udp_socket(server, LDAP_PORT );
	if (sock == -1) {
		DEBUG(2,("ads_cldap_netlogon: Failed to open udp socket to %s\n", 
			 server));
		return False;
	}

	ret = send_cldap_netlogon(sock, realm, global_myname(), 6);
	if (ret != 0) {
		close(sock);
		return False;
	}
	ret = recv_cldap_netlogon(sock, reply);
	close(sock);

	if (ret == -1) {
		return False;
	}

	return True;
}