X-Git-Url: https://vcs.maemo.org/git/?a=blobdiff_plain;f=source%2Flibads%2Fkerberos_verify.c;fp=source%2Flibads%2Fkerberos_verify.c;h=220bf14e32c0dc777a51668ed659186e3ee6a38e;hb=6bca4ca307d55b6dc888e56cee47aebcddbce786;hp=0000000000000000000000000000000000000000;hpb=7fd70fa738b636089bcc6c961aa3eaa02f20dda2;p=samba

diff --git a/source/libads/kerberos_verify.c b/source/libads/kerberos_verify.c
new file mode 100644
index 0000000..220bf14
--- /dev/null
+++ b/source/libads/kerberos_verify.c
@@ -0,0 +1,489 @@
+/* 
+   Unix SMB/CIFS implementation.
+   kerberos utility library
+   Copyright (C) Andrew Tridgell 2001
+   Copyright (C) Remus Koos 2001
+   Copyright (C) Luke Howard 2003   
+   Copyright (C) Guenther Deschner 2003, 2005
+   Copyright (C) Jim McDonough (jmcd@us.ibm.com) 2003
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 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.
+*/
+
+#include "includes.h"
+
+#ifdef HAVE_KRB5
+
+#if !defined(HAVE_KRB5_PRINC_COMPONENT)
+const krb5_data *krb5_princ_component(krb5_context, krb5_principal, int );
+#endif
+
+/**********************************************************************************
+ Try to verify a ticket using the system keytab... the system keytab has kvno -1 entries, so
+ it's more like what microsoft does... see comment in utils/net_ads.c in the
+ ads_keytab_add_entry function for details.
+***********************************************************************************/
+
+static BOOL ads_keytab_verify_ticket(krb5_context context, krb5_auth_context auth_context,
+			const DATA_BLOB *ticket, krb5_data *p_packet, krb5_ticket **pp_tkt, 
+			krb5_keyblock **keyblock)
+{
+	krb5_error_code ret = 0;
+	BOOL auth_ok = False;
+	krb5_keytab keytab = NULL;
+	krb5_kt_cursor kt_cursor;
+	krb5_keytab_entry kt_entry;
+	char *valid_princ_formats[7] = { NULL, NULL, NULL, NULL, NULL, NULL, NULL };
+	char *entry_princ_s = NULL;
+	fstring my_name, my_fqdn;
+	int i;
+	int number_matched_principals = 0;
+
+	/* Generate the list of principal names which we expect
+	 * clients might want to use for authenticating to the file
+	 * service.  We allow name$,{host,cifs}/{name,fqdn,name.REALM}. */
+
+	fstrcpy(my_name, global_myname());
+
+	my_fqdn[0] = '\0';
+	name_to_fqdn(my_fqdn, global_myname());
+
+	asprintf(&valid_princ_formats[0], "%s$@%s", my_name, lp_realm());
+	asprintf(&valid_princ_formats[1], "host/%s@%s", my_name, lp_realm());
+	asprintf(&valid_princ_formats[2], "host/%s@%s", my_fqdn, lp_realm());
+	asprintf(&valid_princ_formats[3], "host/%s.%s@%s", my_name, lp_realm(), lp_realm());
+	asprintf(&valid_princ_formats[4], "cifs/%s@%s", my_name, lp_realm());
+	asprintf(&valid_princ_formats[5], "cifs/%s@%s", my_fqdn, lp_realm());
+	asprintf(&valid_princ_formats[6], "cifs/%s.%s@%s", my_name, lp_realm(), lp_realm());
+
+	ZERO_STRUCT(kt_entry);
+	ZERO_STRUCT(kt_cursor);
+
+	ret = krb5_kt_default(context, &keytab);
+	if (ret) {
+		DEBUG(1, ("ads_keytab_verify_ticket: krb5_kt_default failed (%s)\n", error_message(ret)));
+		goto out;
+	}
+
+	/* Iterate through the keytab.  For each key, if the principal
+	 * name case-insensitively matches one of the allowed formats,
+	 * try verifying the ticket using that principal. */
+
+	ret = krb5_kt_start_seq_get(context, keytab, &kt_cursor);
+	if (ret) {
+		DEBUG(1, ("ads_keytab_verify_ticket: krb5_kt_start_seq_get failed (%s)\n", error_message(ret)));
+		goto out;
+	}
+  
+	if (ret != KRB5_KT_END && ret != ENOENT ) {
+		while (!auth_ok && (krb5_kt_next_entry(context, keytab, &kt_entry, &kt_cursor) == 0)) {
+			ret = krb5_unparse_name(context, kt_entry.principal, &entry_princ_s);
+			if (ret) {
+				DEBUG(1, ("ads_keytab_verify_ticket: krb5_unparse_name failed (%s)\n", error_message(ret)));
+				goto out;
+			}
+
+			for (i = 0; i < sizeof(valid_princ_formats) / sizeof(valid_princ_formats[0]); i++) {
+				if (strequal(entry_princ_s, valid_princ_formats[i])) {
+					number_matched_principals++;
+					p_packet->length = ticket->length;
+					p_packet->data = (krb5_pointer)ticket->data;
+					*pp_tkt = NULL;
+
+					ret = krb5_rd_req_return_keyblock_from_keytab(context, &auth_context, p_packet,
+									  	      kt_entry.principal, keytab,
+										      NULL, pp_tkt, keyblock);
+
+					if (ret) {
+						DEBUG(10,("ads_keytab_verify_ticket: "
+							"krb5_rd_req_return_keyblock_from_keytab(%s) failed: %s\n",
+							entry_princ_s, error_message(ret)));
+					} else {
+						DEBUG(3,("ads_keytab_verify_ticket: "
+							"krb5_rd_req_return_keyblock_from_keytab succeeded for principal %s\n",
+							entry_princ_s));
+						auth_ok = True;
+						break;
+					}
+				}
+			}
+
+			/* Free the name we parsed. */
+			krb5_free_unparsed_name(context, entry_princ_s);
+			entry_princ_s = NULL;
+
+			/* Free the entry we just read. */
+			smb_krb5_kt_free_entry(context, &kt_entry);
+			ZERO_STRUCT(kt_entry);
+		}
+		krb5_kt_end_seq_get(context, keytab, &kt_cursor);
+	}
+
+	ZERO_STRUCT(kt_cursor);
+
+  out:
+	
+	for (i = 0; i < sizeof(valid_princ_formats) / sizeof(valid_princ_formats[0]); i++) {
+		SAFE_FREE(valid_princ_formats[i]);
+	}
+	
+	if (!auth_ok) {
+		if (!number_matched_principals) {
+			DEBUG(3, ("ads_keytab_verify_ticket: no keytab principals matched expected file service name.\n"));
+		} else {
+			DEBUG(3, ("ads_keytab_verify_ticket: krb5_rd_req failed for all %d matched keytab principals\n",
+				number_matched_principals));
+		}
+	}
+
+	if (entry_princ_s) {
+		krb5_free_unparsed_name(context, entry_princ_s);
+	}
+
+	{
+		krb5_keytab_entry zero_kt_entry;
+		ZERO_STRUCT(zero_kt_entry);
+		if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
+			smb_krb5_kt_free_entry(context, &kt_entry);
+		}
+	}
+
+	{
+		krb5_kt_cursor zero_csr;
+		ZERO_STRUCT(zero_csr);
+		if ((memcmp(&kt_cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && keytab) {
+			krb5_kt_end_seq_get(context, keytab, &kt_cursor);
+		}
+	}
+
+	if (keytab) {
+		krb5_kt_close(context, keytab);
+	}
+	return auth_ok;
+}
+
+/**********************************************************************************
+ Try to verify a ticket using the secrets.tdb.
+***********************************************************************************/
+
+static BOOL ads_secrets_verify_ticket(krb5_context context, krb5_auth_context auth_context,
+				      krb5_principal host_princ,
+				      const DATA_BLOB *ticket, krb5_data *p_packet, krb5_ticket **pp_tkt,
+				      krb5_keyblock **keyblock)
+{
+	krb5_error_code ret = 0;
+	BOOL auth_ok = False;
+	char *password_s = NULL;
+	krb5_data password;
+	krb5_enctype *enctypes = NULL;
+	int i;
+
+	ZERO_STRUCTP(keyblock);
+
+	if (!secrets_init()) {
+		DEBUG(1,("ads_secrets_verify_ticket: secrets_init failed\n"));
+		return False;
+	}
+
+	password_s = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
+	if (!password_s) {
+		DEBUG(1,("ads_secrets_verify_ticket: failed to fetch machine password\n"));
+		return False;
+	}
+
+	password.data = password_s;
+	password.length = strlen(password_s);
+
+	/* CIFS doesn't use addresses in tickets. This would break NAT. JRA */
+
+	if ((ret = get_kerberos_allowed_etypes(context, &enctypes))) {
+		DEBUG(1,("ads_secrets_verify_ticket: krb5_get_permitted_enctypes failed (%s)\n", 
+			 error_message(ret)));
+		goto out;
+	}
+
+	p_packet->length = ticket->length;
+	p_packet->data = (krb5_pointer)ticket->data;
+
+	/* We need to setup a auth context with each possible encoding type in turn. */
+	for (i=0;enctypes[i];i++) {
+		krb5_keyblock *key = NULL;
+
+		if (!(key = SMB_MALLOC_P(krb5_keyblock))) {
+			goto out;
+		}
+	
+		if (create_kerberos_key_from_string(context, host_princ, &password, key, enctypes[i])) {
+			SAFE_FREE(key);
+			continue;
+		}
+
+		krb5_auth_con_setuseruserkey(context, auth_context, key);
+
+		if (!(ret = krb5_rd_req(context, &auth_context, p_packet, 
+					NULL,
+					NULL, NULL, pp_tkt))) {
+			DEBUG(10,("ads_secrets_verify_ticket: enc type [%u] decrypted message !\n",
+				(unsigned int)enctypes[i] ));
+			auth_ok = True;
+			krb5_copy_keyblock(context, key, keyblock);
+			krb5_free_keyblock(context, key);
+			break;
+		}
+	
+		DEBUG((ret != KRB5_BAD_ENCTYPE) ? 3 : 10,
+				("ads_secrets_verify_ticket: enc type [%u] failed to decrypt with error %s\n",
+				(unsigned int)enctypes[i], error_message(ret)));
+
+		krb5_free_keyblock(context, key);
+
+	}
+
+ out:
+
+	free_kerberos_etypes(context, enctypes);
+	SAFE_FREE(password_s);
+
+	return auth_ok;
+}
+
+/**********************************************************************************
+ Verify an incoming ticket and parse out the principal name and 
+ authorization_data if available.
+***********************************************************************************/
+
+NTSTATUS ads_verify_ticket(TALLOC_CTX *mem_ctx,
+			   const char *realm, const DATA_BLOB *ticket, 
+			   char **principal, PAC_DATA **pac_data,
+			   DATA_BLOB *ap_rep,
+			   DATA_BLOB *session_key)
+{
+	NTSTATUS sret = NT_STATUS_LOGON_FAILURE;
+	NTSTATUS pac_ret;
+	DATA_BLOB auth_data;
+	krb5_context context = NULL;
+	krb5_auth_context auth_context = NULL;
+	krb5_data packet;
+	krb5_ticket *tkt = NULL;
+	krb5_rcache rcache = NULL;
+	krb5_keyblock *keyblock = NULL;
+	time_t authtime;
+	int ret;
+
+	krb5_principal host_princ = NULL;
+	krb5_const_principal client_principal = NULL;
+	char *host_princ_s = NULL;
+	BOOL got_replay_mutex = False;
+
+	BOOL auth_ok = False;
+	BOOL got_auth_data = False;
+
+	ZERO_STRUCT(packet);
+	ZERO_STRUCT(auth_data);
+	ZERO_STRUCTP(ap_rep);
+	ZERO_STRUCTP(session_key);
+
+	initialize_krb5_error_table();
+	ret = krb5_init_context(&context);
+	if (ret) {
+		DEBUG(1,("ads_verify_ticket: krb5_init_context failed (%s)\n", error_message(ret)));
+		return NT_STATUS_LOGON_FAILURE;
+	}
+
+	ret = krb5_set_default_realm(context, realm);
+	if (ret) {
+		DEBUG(1,("ads_verify_ticket: krb5_set_default_realm failed (%s)\n", error_message(ret)));
+		goto out;
+	}
+
+	/* This whole process is far more complex than I would
+           like. We have to go through all this to allow us to store
+           the secret internally, instead of using /etc/krb5.keytab */
+
+	ret = krb5_auth_con_init(context, &auth_context);
+	if (ret) {
+		DEBUG(1,("ads_verify_ticket: krb5_auth_con_init failed (%s)\n", error_message(ret)));
+		goto out;
+	}
+
+	asprintf(&host_princ_s, "%s$", global_myname());
+	strlower_m(host_princ_s);
+	ret = krb5_parse_name(context, host_princ_s, &host_princ);
+	if (ret) {
+		DEBUG(1,("ads_verify_ticket: krb5_parse_name(%s) failed (%s)\n",
+					host_princ_s, error_message(ret)));
+		goto out;
+	}
+
+
+	/* Lock a mutex surrounding the replay as there is no locking in the MIT krb5
+	 * code surrounding the replay cache... */
+
+	if (!grab_server_mutex("replay cache mutex")) {
+		DEBUG(1,("ads_verify_ticket: unable to protect replay cache with mutex.\n"));
+		goto out;
+	}
+
+	got_replay_mutex = True;
+
+	/*
+	 * JRA. We must set the rcache here. This will prevent replay attacks.
+	 */
+
+	ret = krb5_get_server_rcache(context, krb5_princ_component(context, host_princ, 0), &rcache);
+	if (ret) {
+		DEBUG(1,("ads_verify_ticket: krb5_get_server_rcache failed (%s)\n", error_message(ret)));
+		goto out;
+	}
+
+	ret = krb5_auth_con_setrcache(context, auth_context, rcache);
+	if (ret) {
+		DEBUG(1,("ads_verify_ticket: krb5_auth_con_setrcache failed (%s)\n", error_message(ret)));
+		goto out;
+	}
+
+	if (lp_use_kerberos_keytab()) {
+		auth_ok = ads_keytab_verify_ticket(context, auth_context, ticket, &packet, &tkt, &keyblock);
+	}
+	if (!auth_ok) {
+		auth_ok = ads_secrets_verify_ticket(context, auth_context, host_princ,
+						    ticket, &packet, &tkt, &keyblock);
+	}
+
+	release_server_mutex();
+	got_replay_mutex = False;
+
+#if 0
+	/* Heimdal leaks here, if we fix the leak, MIT crashes */
+	if (rcache) {
+		krb5_rc_close(context, rcache);
+	}
+#endif
+
+	if (!auth_ok) {
+		DEBUG(3,("ads_verify_ticket: krb5_rd_req with auth failed (%s)\n", 
+			 error_message(ret)));
+		goto out;
+	} else {
+		authtime = get_authtime_from_tkt(tkt);
+		client_principal = get_principal_from_tkt(tkt);
+	}
+
+	ret = krb5_mk_rep(context, auth_context, &packet);
+	if (ret) {
+		DEBUG(3,("ads_verify_ticket: Failed to generate mutual authentication reply (%s)\n",
+			error_message(ret)));
+		goto out;
+	}
+
+	*ap_rep = data_blob(packet.data, packet.length);
+	SAFE_FREE(packet.data);
+	packet.length = 0;
+
+	get_krb5_smb_session_key(context, auth_context, session_key, True);
+	dump_data_pw("SMB session key (from ticket)\n", session_key->data, session_key->length);
+
+#if 0
+	file_save("/tmp/ticket.dat", ticket->data, ticket->length);
+#endif
+
+	/* continue when no PAC is retrieved or we couldn't decode the PAC 
+	   (like accounts that have the UF_NO_AUTH_DATA_REQUIRED flag set, or
+	   Kerberos tickets encrypted using a DES key) - Guenther */
+
+	got_auth_data = get_auth_data_from_tkt(mem_ctx, &auth_data, tkt);
+	if (!got_auth_data) {
+		DEBUG(3,("ads_verify_ticket: did not retrieve auth data. continuing without PAC\n"));
+	}
+
+	if (got_auth_data && pac_data != NULL) {
+
+		pac_ret = decode_pac_data(mem_ctx, &auth_data, context, keyblock, client_principal, authtime, pac_data);
+		if (!NT_STATUS_IS_OK(pac_ret)) {
+			DEBUG(3,("ads_verify_ticket: failed to decode PAC_DATA: %s\n", nt_errstr(pac_ret)));
+			*pac_data = NULL;
+		}
+		data_blob_free(&auth_data);
+	}
+
+#if 0
+#if defined(HAVE_KRB5_TKT_ENC_PART2)
+	/* MIT */
+	if (tkt->enc_part2) {
+		file_save("/tmp/authdata.dat",
+			  tkt->enc_part2->authorization_data[0]->contents,
+			  tkt->enc_part2->authorization_data[0]->length);
+	}
+#else
+	/* Heimdal */
+	if (tkt->ticket.authorization_data) {
+		file_save("/tmp/authdata.dat",
+			  tkt->ticket.authorization_data->val->ad_data.data,
+			  tkt->ticket.authorization_data->val->ad_data.length);
+	}
+#endif
+#endif
+
+	if ((ret = krb5_unparse_name(context, get_principal_from_tkt(tkt),
+				     principal))) {
+		DEBUG(3,("ads_verify_ticket: krb5_unparse_name failed (%s)\n", 
+			 error_message(ret)));
+		sret = NT_STATUS_LOGON_FAILURE;
+		goto out;
+	}
+
+	sret = NT_STATUS_OK;
+
+ out:
+
+	if (got_replay_mutex) {
+		release_server_mutex();
+	}
+
+	if (!NT_STATUS_IS_OK(sret)) {
+		data_blob_free(&auth_data);
+	}
+
+	if (!NT_STATUS_IS_OK(sret)) {
+		data_blob_free(ap_rep);
+	}
+
+	if (host_princ) {
+		krb5_free_principal(context, host_princ);
+	}
+
+	if (keyblock) {
+		krb5_free_keyblock(context, keyblock);
+	}
+
+	if (tkt != NULL) {
+		krb5_free_ticket(context, tkt);
+	}
+
+	SAFE_FREE(host_princ_s);
+
+	if (auth_context) {
+		krb5_auth_con_free(context, auth_context);
+	}
+
+	if (context) {
+		krb5_free_context(context);
+	}
+
+	return sret;
+}
+
+#endif /* HAVE_KRB5 */