1 files changed, 819 insertions, 0 deletions
diff --git a/source3/libads/krb5_setpw.c b/source3/libads/krb5_setpw.c
new file mode 100644
index 0000000000..719f3bd3ec
--- /dev/null
+++ b/source3/libads/krb5_setpw.c
@@ -0,0 +1,819 @@
+/* 
+   Unix SMB/CIFS implementation.
+   krb5 set password implementation
+   Copyright (C) Andrew Tridgell 2001
+   Copyright (C) Remus Koos 2001 (remuskoos@yahoo.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 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"
+
+#ifdef HAVE_KRB5
+
+#define DEFAULT_KPASSWD_PORT	464
+
+#define KRB5_KPASSWD_VERS_CHANGEPW		1
+
+#define KRB5_KPASSWD_VERS_SETPW			0xff80
+#define KRB5_KPASSWD_VERS_SETPW_ALT		2
+
+#define KRB5_KPASSWD_SUCCESS			0
+#define KRB5_KPASSWD_MALFORMED			1
+#define KRB5_KPASSWD_HARDERROR			2
+#define KRB5_KPASSWD_AUTHERROR			3
+#define KRB5_KPASSWD_SOFTERROR			4
+#define KRB5_KPASSWD_ACCESSDENIED		5
+#define KRB5_KPASSWD_BAD_VERSION		6
+#define KRB5_KPASSWD_INITIAL_FLAG_NEEDED	7
+
+/* Those are defined by kerberos-set-passwd-02.txt and are probably 
+ * not supported by M$ implementation */
+#define KRB5_KPASSWD_POLICY_REJECT		8
+#define KRB5_KPASSWD_BAD_PRINCIPAL		9
+#define KRB5_KPASSWD_ETYPE_NOSUPP		10
+
+/*
+ * we've got to be able to distinguish KRB_ERRORs from other
+ * requests - valid response for CHPW v2 replies.
+ */
+
+#define krb5_is_krb_error(packet) \
+	( packet && packet->length && (((char *)packet->data)[0] == 0x7e || ((char *)packet->data)[0] == 0x5e))
+
+/* This implements kerberos password change protocol as specified in 
+ * kerb-chg-password-02.txt and kerberos-set-passwd-02.txt
+ * as well as microsoft version of the protocol 
+ * as specified in kerberos-set-passwd-00.txt
+ */
+static DATA_BLOB encode_krb5_setpw(const char *principal, const char *password)
+{
+        char* princ_part1 = NULL;
+	char* princ_part2 = NULL;
+	char* realm = NULL;
+	char* c;
+	char* princ;
+
+	ASN1_DATA req;
+	DATA_BLOB ret;
+
+
+	princ = SMB_STRDUP(principal);
+
+	if ((c = strchr_m(princ, '/')) == NULL) {
+		c = princ; 
+	} else {
+		*c = '\0';
+		c++;
+		princ_part1 = princ;
+	}
+
+	princ_part2 = c;
+
+	if ((c = strchr_m(c, '@')) != NULL) {
+		*c = '\0';
+		c++;
+		realm = c;
+	} else {
+		/* We must have a realm component. */
+		return data_blob_null;
+	}
+
+	memset(&req, 0, sizeof(req));
+	
+	asn1_push_tag(&req, ASN1_SEQUENCE(0));
+	asn1_push_tag(&req, ASN1_CONTEXT(0));
+	asn1_write_OctetString(&req, password, strlen(password));
+	asn1_pop_tag(&req);
+
+	asn1_push_tag(&req, ASN1_CONTEXT(1));
+	asn1_push_tag(&req, ASN1_SEQUENCE(0));
+
+	asn1_push_tag(&req, ASN1_CONTEXT(0));
+	asn1_write_Integer(&req, 1);
+	asn1_pop_tag(&req);
+
+	asn1_push_tag(&req, ASN1_CONTEXT(1));
+	asn1_push_tag(&req, ASN1_SEQUENCE(0));
+
+	if (princ_part1) {
+		asn1_write_GeneralString(&req, princ_part1);
+	}
+	
+	asn1_write_GeneralString(&req, princ_part2);
+	asn1_pop_tag(&req);
+	asn1_pop_tag(&req);
+	asn1_pop_tag(&req);
+	asn1_pop_tag(&req);
+
+	asn1_push_tag(&req, ASN1_CONTEXT(2));
+	asn1_write_GeneralString(&req, realm);
+	asn1_pop_tag(&req);
+	asn1_pop_tag(&req);
+
+	ret = data_blob(req.data, req.length);
+	asn1_free(&req);
+
+	free(princ);
+
+	return ret;
+}	
+
+static krb5_error_code build_kpasswd_request(uint16 pversion,
+					   krb5_context context,
+					   krb5_auth_context auth_context,
+					   krb5_data *ap_req,
+					   const char *princ,
+					   const char *passwd,
+					   bool use_tcp,
+					   krb5_data *packet)
+{
+	krb5_error_code ret;
+	krb5_data cipherpw;
+	krb5_data encoded_setpw;
+	krb5_replay_data replay;
+	char *p, *msg_start;
+	DATA_BLOB setpw;
+	unsigned int msg_length;
+
+	ret = krb5_auth_con_setflags(context,
+				     auth_context,KRB5_AUTH_CONTEXT_DO_SEQUENCE);
+	if (ret) {
+		DEBUG(1,("krb5_auth_con_setflags failed (%s)\n",
+			 error_message(ret)));
+		return ret;
+	}
+
+	/* handle protocol differences in chpw and setpw */
+	if (pversion  == KRB5_KPASSWD_VERS_CHANGEPW)
+		setpw = data_blob(passwd, strlen(passwd));
+	else if (pversion == KRB5_KPASSWD_VERS_SETPW ||
+		 pversion == KRB5_KPASSWD_VERS_SETPW_ALT)
+		setpw = encode_krb5_setpw(princ, passwd);
+	else
+		return EINVAL;
+
+	if (setpw.data == NULL || setpw.length == 0) {
+		return EINVAL;
+	}
+
+	encoded_setpw.data = (char *)setpw.data;
+	encoded_setpw.length = setpw.length;
+
+	ret = krb5_mk_priv(context, auth_context,
+			   &encoded_setpw, &cipherpw, &replay);
+	
+	data_blob_free(&setpw); 	/*from 'encode_krb5_setpw(...)' */
+	
+	if (ret) {
+		DEBUG(1,("krb5_mk_priv failed (%s)\n", error_message(ret)));
+		return ret;
+	}
+
+	packet->data = (char *)SMB_MALLOC(ap_req->length + cipherpw.length + (use_tcp ? 10 : 6 ));
+	if (!packet->data)
+		return -1;
+
+
+
+	/* see the RFC for details */
+
+	msg_start = p = ((char *)packet->data) + (use_tcp ? 4 : 0);
+	p += 2;
+	RSSVAL(p, 0, pversion);
+	p += 2;
+	RSSVAL(p, 0, ap_req->length);
+	p += 2;
+	memcpy(p, ap_req->data, ap_req->length);
+	p += ap_req->length;
+	memcpy(p, cipherpw.data, cipherpw.length);
+	p += cipherpw.length;
+	packet->length = PTR_DIFF(p,packet->data);
+	msg_length = PTR_DIFF(p,msg_start);
+
+	if (use_tcp) {
+		RSIVAL(packet->data, 0, msg_length);
+	}
+	RSSVAL(msg_start, 0, msg_length);
+	
+	free(cipherpw.data);    /* from 'krb5_mk_priv(...)' */
+
+	return 0;
+}
+
+static const struct kpasswd_errors {
+	int result_code;
+	const char *error_string;
+} kpasswd_errors[] = {
+	{KRB5_KPASSWD_MALFORMED, "Malformed request error"},
+	{KRB5_KPASSWD_HARDERROR, "Server error"},
+	{KRB5_KPASSWD_AUTHERROR, "Authentication error"},
+	{KRB5_KPASSWD_SOFTERROR, "Password change rejected"},
+	{KRB5_KPASSWD_ACCESSDENIED, "Client does not have proper authorization"},
+	{KRB5_KPASSWD_BAD_VERSION, "Protocol version not supported"},
+	{KRB5_KPASSWD_INITIAL_FLAG_NEEDED, "Authorization ticket must have initial flag set"},
+	{KRB5_KPASSWD_POLICY_REJECT, "Password rejected due to policy requirements"},
+	{KRB5_KPASSWD_BAD_PRINCIPAL, "Target principal does not exist"},
+	{KRB5_KPASSWD_ETYPE_NOSUPP, "Unsupported encryption type"},
+	{0, NULL}
+};
+
+static krb5_error_code setpw_result_code_string(krb5_context context,
+						int result_code,
+						const char **code_string)
+{
+        unsigned int idx = 0;
+
+	while (kpasswd_errors[idx].error_string != NULL) {
+		if (kpasswd_errors[idx].result_code == 
+                    result_code) {
+			*code_string = kpasswd_errors[idx].error_string;
+			return 0;
+		}
+		idx++;
+	}
+	*code_string = "Password change failed";
+        return (0);
+}
+
+ krb5_error_code kpasswd_err_to_krb5_err(krb5_error_code res_code) 
+{
+	switch(res_code) {
+		case KRB5_KPASSWD_ACCESSDENIED:
+			return KRB5KDC_ERR_BADOPTION;
+		case KRB5_KPASSWD_INITIAL_FLAG_NEEDED:
+			return KRB5KDC_ERR_BADOPTION;
+			/* return KV5M_ALT_METHOD; MIT-only define */
+		case KRB5_KPASSWD_ETYPE_NOSUPP:
+			return KRB5KDC_ERR_ETYPE_NOSUPP;
+		case KRB5_KPASSWD_BAD_PRINCIPAL:
+			return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
+		case KRB5_KPASSWD_POLICY_REJECT:
+		case KRB5_KPASSWD_SOFTERROR:
+			return KRB5KDC_ERR_POLICY;
+		default:
+			return KRB5KRB_ERR_GENERIC;
+	}
+}
+static krb5_error_code parse_setpw_reply(krb5_context context,
+					 bool use_tcp,
+					 krb5_auth_context auth_context,
+					 krb5_data *packet)
+{
+	krb5_data ap_rep;
+	char *p;
+	int vnum, ret, res_code;
+	krb5_data cipherresult;
+	krb5_data clearresult;
+	krb5_ap_rep_enc_part *ap_rep_enc;
+	krb5_replay_data replay;
+	unsigned int msg_length = packet->length;
+
+
+	if (packet->length < (use_tcp ? 8 : 4)) {
+		return KRB5KRB_AP_ERR_MODIFIED;
+	}
+	
+	p = packet->data;
+	/*
+	** see if it is an error
+	*/
+	if (krb5_is_krb_error(packet)) {
+
+		ret = handle_krberror_packet(context, packet);
+		if (ret) {
+			return ret;
+		}
+	}
+
+	
+	/* tcp... */
+	if (use_tcp) {
+		msg_length -= 4;
+		if (RIVAL(p, 0) != msg_length) {
+			DEBUG(1,("Bad TCP packet length (%d/%d) from kpasswd server\n",
+			RIVAL(p, 0), msg_length));
+			return KRB5KRB_AP_ERR_MODIFIED;
+		}
+
+		p += 4;
+	}
+	
+	if (RSVAL(p, 0) != msg_length) {
+		DEBUG(1,("Bad packet length (%d/%d) from kpasswd server\n",
+			 RSVAL(p, 0), msg_length));
+		return KRB5KRB_AP_ERR_MODIFIED;
+	}
+
+	p += 2;
+
+	vnum = RSVAL(p, 0); p += 2;
+
+	/* FIXME: According to standard there is only one type of reply */	
+	if (vnum != KRB5_KPASSWD_VERS_SETPW && 
+	    vnum != KRB5_KPASSWD_VERS_SETPW_ALT && 
+	    vnum != KRB5_KPASSWD_VERS_CHANGEPW) {
+		DEBUG(1,("Bad vnum (%d) from kpasswd server\n", vnum));
+		return KRB5KDC_ERR_BAD_PVNO;
+	}
+	
+	ap_rep.length = RSVAL(p, 0); p += 2;
+	
+	if (p + ap_rep.length >= (char *)packet->data + packet->length) {
+		DEBUG(1,("ptr beyond end of packet from kpasswd server\n"));
+		return KRB5KRB_AP_ERR_MODIFIED;
+	}
+	
+	if (ap_rep.length == 0) {
+		DEBUG(1,("got unencrypted setpw result?!\n"));
+		return KRB5KRB_AP_ERR_MODIFIED;
+	}
+
+	/* verify ap_rep */
+	ap_rep.data = p;
+	p += ap_rep.length;
+	
+	ret = krb5_rd_rep(context, auth_context, &ap_rep, &ap_rep_enc);
+	if (ret) {
+		DEBUG(1,("failed to rd setpw reply (%s)\n", error_message(ret)));
+		return KRB5KRB_AP_ERR_MODIFIED;
+	}
+	
+	krb5_free_ap_rep_enc_part(context, ap_rep_enc);
+	
+	cipherresult.data = p;
+	cipherresult.length = ((char *)packet->data + packet->length) - p;
+		
+	ret = krb5_rd_priv(context, auth_context, &cipherresult, &clearresult,
+			   &replay);
+	if (ret) {
+		DEBUG(1,("failed to decrypt setpw reply (%s)\n", error_message(ret)));
+		return KRB5KRB_AP_ERR_MODIFIED;
+	}
+
+	if (clearresult.length < 2) {
+	        free(clearresult.data);
+		ret = KRB5KRB_AP_ERR_MODIFIED;
+		return KRB5KRB_AP_ERR_MODIFIED;
+	}
+	
+	p = clearresult.data;
+	
+	res_code = RSVAL(p, 0);
+	
+	free(clearresult.data);
+
+	if ((res_code < KRB5_KPASSWD_SUCCESS) || 
+	    (res_code > KRB5_KPASSWD_ETYPE_NOSUPP)) {
+		return KRB5KRB_AP_ERR_MODIFIED;
+	}
+
+	if (res_code == KRB5_KPASSWD_SUCCESS) {
+		return 0;
+	} else {
+		const char *errstr;
+		setpw_result_code_string(context, res_code, &errstr);
+		DEBUG(1, ("Error changing password: %s (%d)\n", errstr, res_code));
+
+		return kpasswd_err_to_krb5_err(res_code);
+	}
+}
+
+static ADS_STATUS do_krb5_kpasswd_request(krb5_context context,
+					  const char *kdc_host,
+					  uint16 pversion,
+					  krb5_creds *credsp,
+					  const char *princ,
+					  const char *newpw)
+{
+	krb5_auth_context auth_context = NULL;
+	krb5_data ap_req, chpw_req, chpw_rep;
+	int ret, sock;
+	socklen_t addr_len;
+	struct sockaddr_storage remote_addr, local_addr;
+	struct sockaddr_storage addr;
+	krb5_address local_kaddr, remote_kaddr;
+	bool use_tcp = False;
+
+
+	if (!interpret_string_addr(&addr, kdc_host, 0)) {
+	}
+
+	ret = krb5_mk_req_extended(context, &auth_context, AP_OPTS_USE_SUBKEY,
+				   NULL, credsp, &ap_req);
+	if (ret) {
+		DEBUG(1,("krb5_mk_req_extended failed (%s)\n", error_message(ret)));
+		return ADS_ERROR_KRB5(ret);
+	}
+
+	do {
+
+		if (!use_tcp) {
+
+			sock = open_udp_socket(kdc_host, DEFAULT_KPASSWD_PORT);
+
+		} else {
+
+			sock = open_socket_out(SOCK_STREAM, &addr, DEFAULT_KPASSWD_PORT, 
+					       LONG_CONNECT_TIMEOUT);
+		}
+
+		if (sock == -1) {
+			int rc = errno;
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			DEBUG(1,("failed to open kpasswd socket to %s (%s)\n",
+				 kdc_host, strerror(errno)));
+			return ADS_ERROR_SYSTEM(rc);
+		}
+		addr_len = sizeof(remote_addr);
+		if (getpeername(sock, (struct sockaddr *)&remote_addr, &addr_len) != 0) {
+			close(sock);
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			DEBUG(1,("getpeername() failed (%s)\n", error_message(errno)));
+			return ADS_ERROR_SYSTEM(errno);
+		}
+		addr_len = sizeof(local_addr);
+		if (getsockname(sock, (struct sockaddr *)&local_addr, &addr_len) != 0) {
+			close(sock);
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			DEBUG(1,("getsockname() failed (%s)\n", error_message(errno)));
+			return ADS_ERROR_SYSTEM(errno);
+		}
+		if (!setup_kaddr(&remote_kaddr, &remote_addr) ||
+				!setup_kaddr(&local_kaddr, &local_addr)) {
+			DEBUG(1,("do_krb5_kpasswd_request: "
+				"Failed to setup addresses.\n"));
+			close(sock);
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			errno = EINVAL;
+			return ADS_ERROR_SYSTEM(EINVAL);
+		}
+
+		ret = krb5_auth_con_setaddrs(context, auth_context, &local_kaddr, NULL);
+		if (ret) {
+			close(sock);
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			DEBUG(1,("krb5_auth_con_setaddrs failed (%s)\n", error_message(ret)));
+			return ADS_ERROR_KRB5(ret);
+		}
+
+		ret = build_kpasswd_request(pversion, context, auth_context, &ap_req,
+					  princ, newpw, use_tcp, &chpw_req);
+		if (ret) {
+			close(sock);
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			DEBUG(1,("build_setpw_request failed (%s)\n", error_message(ret)));
+			return ADS_ERROR_KRB5(ret);
+		}
+
+		ret = write(sock, chpw_req.data, chpw_req.length); 
+
+		if (ret != chpw_req.length) {
+			close(sock);
+			SAFE_FREE(chpw_req.data);
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			DEBUG(1,("send of chpw failed (%s)\n", strerror(errno)));
+			return ADS_ERROR_SYSTEM(errno);
+		}
+	
+		SAFE_FREE(chpw_req.data);
+	
+		chpw_rep.length = 1500;
+		chpw_rep.data = (char *) SMB_MALLOC(chpw_rep.length);
+		if (!chpw_rep.data) {
+			close(sock);
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			DEBUG(1,("send of chpw failed (%s)\n", strerror(errno)));
+			errno = ENOMEM;
+			return ADS_ERROR_SYSTEM(errno);
+		}
+	
+		ret = read(sock, chpw_rep.data, chpw_rep.length);
+		if (ret < 0) {
+			close(sock);
+			SAFE_FREE(chpw_rep.data);
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			DEBUG(1,("recv of chpw reply failed (%s)\n", strerror(errno)));
+			return ADS_ERROR_SYSTEM(errno);
+		}
+	
+		close(sock);
+		chpw_rep.length = ret;
+	
+		ret = krb5_auth_con_setaddrs(context, auth_context, NULL,&remote_kaddr);
+		if (ret) {
+			SAFE_FREE(chpw_rep.data);
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			DEBUG(1,("krb5_auth_con_setaddrs on reply failed (%s)\n", 
+				 error_message(ret)));
+			return ADS_ERROR_KRB5(ret);
+		}
+	
+		ret = parse_setpw_reply(context, use_tcp, auth_context, &chpw_rep);
+		SAFE_FREE(chpw_rep.data);
+	
+		if (ret) {
+			
+			if (ret == KRB5KRB_ERR_RESPONSE_TOO_BIG && !use_tcp) {
+				DEBUG(5, ("Trying setpw with TCP!!!\n"));
+				use_tcp = True;
+				continue;
+			}
+
+			SAFE_FREE(ap_req.data);
+			krb5_auth_con_free(context, auth_context);
+			DEBUG(1,("parse_setpw_reply failed (%s)\n", 
+				 error_message(ret)));
+			return ADS_ERROR_KRB5(ret);
+		}
+	
+		SAFE_FREE(ap_req.data);
+		krb5_auth_con_free(context, auth_context);
+	} while ( ret );
+
+	return ADS_SUCCESS;
+}
+
+ADS_STATUS ads_krb5_set_password(const char *kdc_host, const char *princ, 
+				 const char *newpw, int time_offset)
+{
+
+	ADS_STATUS aret;
+	krb5_error_code ret = 0;
+	krb5_context context = NULL;
+	krb5_principal principal = NULL;
+	char *princ_name = NULL;
+	char *realm = NULL;
+	krb5_creds creds, *credsp = NULL;
+#if KRB5_PRINC_REALM_RETURNS_REALM
+	krb5_realm orig_realm;
+#else
+	krb5_data orig_realm;
+#endif
+	krb5_ccache ccache = NULL;
+
+	ZERO_STRUCT(creds);
+	
+	initialize_krb5_error_table();
+	ret = krb5_init_context(&context);
+	if (ret) {
+		DEBUG(1,("Failed to init krb5 context (%s)\n", error_message(ret)));
+		return ADS_ERROR_KRB5(ret);
+	}
+	
+	if (time_offset != 0) {
+		krb5_set_real_time(context, time(NULL) + time_offset, 0);
+	}
+
+	ret = krb5_cc_default(context, &ccache);
+	if (ret) {
+	        krb5_free_context(context);
+		DEBUG(1,("Failed to get default creds (%s)\n", error_message(ret)));
+		return ADS_ERROR_KRB5(ret);
+	}
+
+	realm = strchr_m(princ, '@');
+	if (!realm) {
+		krb5_cc_close(context, ccache);
+	        krb5_free_context(context);
+		DEBUG(1,("Failed to get realm\n"));
+		return ADS_ERROR_KRB5(-1);
+	}
+	realm++;
+
+	asprintf(&princ_name, "kadmin/changepw@%s", realm);
+	ret = smb_krb5_parse_name(context, princ_name, &creds.server);
+	if (ret) {
+		krb5_cc_close(context, ccache);
+                krb5_free_context(context);
+		DEBUG(1,("Failed to parse kadmin/changepw (%s)\n", error_message(ret)));
+		return ADS_ERROR_KRB5(ret);
+	}
+
+	/* parse the principal we got as a function argument */
+	ret = smb_krb5_parse_name(context, princ, &principal);
+	if (ret) {
+		krb5_cc_close(context, ccache);
+	        krb5_free_principal(context, creds.server);
+                krb5_free_context(context);
+		DEBUG(1,("Failed to parse %s (%s)\n", princ_name, error_message(ret)));
+		free(princ_name);
+		return ADS_ERROR_KRB5(ret);
+	}
+
+	free(princ_name);
+
+	/* The creds.server principal takes ownership of this memory.
+		Remember to set back to original value before freeing. */
+	orig_realm = *krb5_princ_realm(context, creds.server);
+	krb5_princ_set_realm(context, creds.server, krb5_princ_realm(context, principal));
+	
+	ret = krb5_cc_get_principal(context, ccache, &creds.client);
+	if (ret) {
+		krb5_cc_close(context, ccache);
+		krb5_princ_set_realm(context, creds.server, &orig_realm);
+	        krb5_free_principal(context, creds.server);
+	        krb5_free_principal(context, principal);
+                krb5_free_context(context);
+		DEBUG(1,("Failed to get principal from ccache (%s)\n", 
+			 error_message(ret)));
+		return ADS_ERROR_KRB5(ret);
+	}
+	
+	ret = krb5_get_credentials(context, 0, ccache, &creds, &credsp); 
+	if (ret) {
+		krb5_cc_close(context, ccache);
+	        krb5_free_principal(context, creds.client);
+		krb5_princ_set_realm(context, creds.server, &orig_realm);
+	        krb5_free_principal(context, creds.server);
+	        krb5_free_principal(context, principal);
+	        krb5_free_context(context);
+		DEBUG(1,("krb5_get_credentials failed (%s)\n", error_message(ret)));
+		return ADS_ERROR_KRB5(ret);
+	}
+	
+	/* we might have to call krb5_free_creds(...) from now on ... */
+
+	aret = do_krb5_kpasswd_request(context, kdc_host,
+				       KRB5_KPASSWD_VERS_SETPW,
+				       credsp, princ, newpw);
+
+	krb5_free_creds(context, credsp);
+	krb5_free_principal(context, creds.client);
+	krb5_princ_set_realm(context, creds.server, &orig_realm);
+        krb5_free_principal(context, creds.server);
+	krb5_free_principal(context, principal);
+	krb5_cc_close(context, ccache);
+	krb5_free_context(context);
+
+	return aret;
+}
+
+/*
+  we use a prompter to avoid a crash bug in the kerberos libs when 
+  dealing with empty passwords
+  this prompter is just a string copy ...
+*/
+static krb5_error_code 
+kerb_prompter(krb5_context ctx, void *data,
+	       const char *name,
+	       const char *banner,
+	       int num_prompts,
+	       krb5_prompt prompts[])
+{
+	if (num_prompts == 0) return 0;
+
+	memset(prompts[0].reply->data, 0, prompts[0].reply->length);
+	if (prompts[0].reply->length > 0) {
+		if (data) {
+			strncpy(prompts[0].reply->data,
+				(const char *)data,
+				prompts[0].reply->length-1);
+			prompts[0].reply->length = strlen(prompts[0].reply->data);
+		} else {
+			prompts[0].reply->length = 0;
+		}
+	}
+	return 0;
+}
+
+static ADS_STATUS ads_krb5_chg_password(const char *kdc_host,
+					const char *principal,
+					const char *oldpw, 
+					const char *newpw, 
+					int time_offset)
+{
+    ADS_STATUS aret;
+    krb5_error_code ret;
+    krb5_context context = NULL;
+    krb5_principal princ;
+    krb5_get_init_creds_opt opts;
+    krb5_creds creds;
+    char *chpw_princ = NULL, *password;
+
+    initialize_krb5_error_table();
+    ret = krb5_init_context(&context);
+    if (ret) {
+	DEBUG(1,("Failed to init krb5 context (%s)\n", error_message(ret)));
+	return ADS_ERROR_KRB5(ret);
+    }
+
+    if ((ret = smb_krb5_parse_name(context, principal,
+                                    &princ))) {
+	krb5_free_context(context);
+	DEBUG(1,("Failed to parse %s (%s)\n", principal, error_message(ret)));
+	return ADS_ERROR_KRB5(ret);
+    }
+
+    krb5_get_init_creds_opt_init(&opts);
+    krb5_get_init_creds_opt_set_tkt_life(&opts, 5*60);
+    krb5_get_init_creds_opt_set_renew_life(&opts, 0);
+    krb5_get_init_creds_opt_set_forwardable(&opts, 0);
+    krb5_get_init_creds_opt_set_proxiable(&opts, 0);
+
+    /* We have to obtain an INITIAL changepw ticket for changing password */
+    asprintf(&chpw_princ, "kadmin/changepw@%s",
+				(char *) krb5_princ_realm(context, princ));
+    password = SMB_STRDUP(oldpw);
+    ret = krb5_get_init_creds_password(context, &creds, princ, password,
+					   kerb_prompter, NULL, 
+					   0, chpw_princ, &opts);
+    SAFE_FREE(chpw_princ);
+    SAFE_FREE(password);
+
+    if (ret) {
+      if (ret == KRB5KRB_AP_ERR_BAD_INTEGRITY)
+	DEBUG(1,("Password incorrect while getting initial ticket"));
+      else
+	DEBUG(1,("krb5_get_init_creds_password failed (%s)\n", error_message(ret)));
+
+	krb5_free_principal(context, princ);
+	krb5_free_context(context);
+	return ADS_ERROR_KRB5(ret);
+    }
+
+    aret = do_krb5_kpasswd_request(context, kdc_host,
+				   KRB5_KPASSWD_VERS_CHANGEPW,
+				   &creds, principal, newpw);
+
+    krb5_free_principal(context, princ);
+    krb5_free_context(context);
+
+    return aret;
+}
+
+
+ADS_STATUS kerberos_set_password(const char *kpasswd_server, 
+				 const char *auth_principal, const char *auth_password,
+				 const char *target_principal, const char *new_password,
+				 int time_offset)
+{
+    int ret;
+
+    if ((ret = kerberos_kinit_password(auth_principal, auth_password, time_offset, NULL))) {
+	DEBUG(1,("Failed kinit for principal %s (%s)\n", auth_principal, error_message(ret)));
+	return ADS_ERROR_KRB5(ret);
+    }
+
+    if (!strcmp(auth_principal, target_principal))
+	return ads_krb5_chg_password(kpasswd_server, target_principal,
+				     auth_password, new_password, time_offset);
+    else
+    	return ads_krb5_set_password(kpasswd_server, target_principal,
+				     new_password, time_offset);
+}
+
+
+/**
+ * Set the machine account password
+ * @param ads connection to ads server
+ * @param hostname machine whose password is being set
+ * @param password new password
+ * @return status of password change
+ **/
+ADS_STATUS ads_set_machine_password(ADS_STRUCT *ads,
+				    const char *machine_account,
+				    const char *password)
+{
+	ADS_STATUS status;
+	char *principal = NULL; 
+
+	/*
+	  we need to use the '$' form of the name here (the machine account name), 
+	  as otherwise the server might end up setting the password for a user
+	  instead
+	 */
+	asprintf(&principal, "%s@%s", machine_account, ads->config.realm);
+	
+	status = ads_krb5_set_password(ads->auth.kdc_server, principal, 
+				       password, ads->auth.time_offset);
+	
+	free(principal);
+
+	return status;
+}
+
+
+
+#endif