--- /dev/null
+/*
+ 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 */
projects / samba / blobdiff