Adding upstream version 2:4.17.12+dfsg.upstream/2%4.17.12+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 391 insertions, 0 deletions

diff --git a/source4/kdc/kpasswd-service.c b/source4/kdc/kpasswd-service.c
new file mode 100644
index 0000000..d2f1bb0
--- /dev/null
+++ b/source4/kdc/kpasswd-service.c
@@ -0,0 +1,391 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   Samba kpasswd implementation
+
+   Copyright (c) 2005      Andrew Bartlett <abartlet@samba.org>
+   Copyright (c) 2016      Andreas Schneider <asn@samba.org>
+
+   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 "samba/service_task.h"
+#include "tsocket/tsocket.h"
+#include "auth/credentials/credentials.h"
+#include "auth/auth.h"
+#include "auth/gensec/gensec.h"
+#include "kdc/kdc-server.h"
+#include "kdc/kpasswd-service.h"
+#include "kdc/kpasswd-helper.h"
+#include "param/param.h"
+
+#define HEADER_LEN 6
+#ifndef RFC3244_VERSION
+#define RFC3244_VERSION 0xff80
+#endif
+
+kdc_code kpasswd_process(struct kdc_server *kdc,
+			 TALLOC_CTX *mem_ctx,
+			 DATA_BLOB *request,
+			 DATA_BLOB *reply,
+			 struct tsocket_address *remote_addr,
+			 struct tsocket_address *local_addr,
+			 int datagram)
+{
+	uint16_t len;
+	uint16_t verno;
+	uint16_t ap_req_len;
+	uint16_t enc_data_len;
+	DATA_BLOB ap_req_blob = data_blob_null;
+	DATA_BLOB ap_rep_blob = data_blob_null;
+	DATA_BLOB enc_data_blob = data_blob_null;
+	DATA_BLOB dec_data_blob = data_blob_null;
+	DATA_BLOB kpasswd_dec_reply = data_blob_null;
+	const char *error_string = NULL;
+	krb5_error_code error_code = 0;
+	struct cli_credentials *server_credentials;
+	struct gensec_security *gensec_security;
+#ifndef SAMBA4_USES_HEIMDAL
+	struct sockaddr_storage remote_ss;
+#endif
+	struct sockaddr_storage local_ss;
+	ssize_t socklen;
+	TALLOC_CTX *tmp_ctx;
+	kdc_code rc = KDC_ERROR;
+	krb5_error_code code = 0;
+	NTSTATUS status;
+	int rv;
+	bool is_inet;
+	bool ok;
+
+	if (kdc->am_rodc) {
+		return KDC_PROXY_REQUEST;
+	}
+
+	tmp_ctx = talloc_new(mem_ctx);
+	if (tmp_ctx == NULL) {
+		return KDC_ERROR;
+	}
+
+	is_inet = tsocket_address_is_inet(remote_addr, "ip");
+	if (!is_inet) {
+		DBG_WARNING("Invalid remote IP address");
+		goto done;
+	}
+
+#ifndef SAMBA4_USES_HEIMDAL
+	/*
+	 * FIXME: Heimdal fails to to do a krb5_rd_req() in gensec_krb5 if we
+	 * set the remote address.
+	 */
+
+	/* remote_addr */
+	socklen = tsocket_address_bsd_sockaddr(remote_addr,
+					       (struct sockaddr *)&remote_ss,
+					       sizeof(struct sockaddr_storage));
+	if (socklen < 0) {
+		DBG_WARNING("Invalid remote IP address");
+		goto done;
+	}
+#endif
+
+	/* local_addr */
+	socklen = tsocket_address_bsd_sockaddr(local_addr,
+					       (struct sockaddr *)&local_ss,
+					       sizeof(struct sockaddr_storage));
+	if (socklen < 0) {
+		DBG_WARNING("Invalid local IP address");
+		goto done;
+	}
+
+	if (request->length <= HEADER_LEN) {
+		DBG_WARNING("Request truncated\n");
+		goto done;
+	}
+
+	len = RSVAL(request->data, 0);
+	if (request->length != len) {
+		DBG_WARNING("Request length does not match\n");
+		goto done;
+	}
+
+	verno = RSVAL(request->data, 2);
+	if (verno != 1 && verno != RFC3244_VERSION) {
+		DBG_WARNING("Unsupported version: 0x%04x\n", verno);
+	}
+
+	ap_req_len = RSVAL(request->data, 4);
+	if ((ap_req_len >= len) || ((ap_req_len + HEADER_LEN) >= len)) {
+		DBG_WARNING("AP_REQ truncated\n");
+		goto done;
+	}
+
+	ap_req_blob = data_blob_const(&request->data[HEADER_LEN], ap_req_len);
+
+	enc_data_len = len - ap_req_len;
+	enc_data_blob = data_blob_const(&request->data[HEADER_LEN + ap_req_len],
+					enc_data_len);
+
+	server_credentials = cli_credentials_init(tmp_ctx);
+	if (server_credentials == NULL) {
+		DBG_ERR("Failed to initialize server credentials!\n");
+		goto done;
+	}
+
+	/*
+	 * We want the credentials subsystem to use the krb5 context we already
+	 * have, rather than a new context.
+	 *
+	 * On this context the KDB plugin has been loaded, so we can access
+	 * dsdb.
+	 */
+	status = cli_credentials_set_krb5_context(server_credentials,
+						  kdc->smb_krb5_context);
+	if (!NT_STATUS_IS_OK(status)) {
+		goto done;
+	}
+
+	ok = cli_credentials_set_conf(server_credentials, kdc->task->lp_ctx);
+	if (!ok) {
+		goto done;
+	}
+
+	/*
+	 * After calling cli_credentials_set_conf(), explicitly set the realm
+	 * with CRED_SPECIFIED. We need to do this so the result of
+	 * principal_from_credentials() called from the gensec layer is
+	 * CRED_SPECIFIED rather than CRED_SMB_CONF, avoiding a fallback to
+	 * match-by-key (very undesirable in this case).
+	 */
+	ok = cli_credentials_set_realm(server_credentials,
+				       lpcfg_realm(kdc->task->lp_ctx),
+				       CRED_SPECIFIED);
+	if (!ok) {
+		goto done;
+	}
+
+	ok = cli_credentials_set_username(server_credentials,
+					  "kadmin/changepw",
+					  CRED_SPECIFIED);
+	if (!ok) {
+		goto done;
+	}
+
+	/* Check that the server principal is indeed CRED_SPECIFIED. */
+	{
+		char *principal = NULL;
+		enum credentials_obtained obtained;
+
+		principal = cli_credentials_get_principal_and_obtained(server_credentials,
+								       tmp_ctx,
+								       &obtained);
+		if (obtained < CRED_SPECIFIED) {
+			goto done;
+		}
+
+		TALLOC_FREE(principal);
+	}
+
+	rv = cli_credentials_set_keytab_name(server_credentials,
+					     kdc->task->lp_ctx,
+					     kdc->kpasswd_keytab_name,
+					     CRED_SPECIFIED);
+	if (rv != 0) {
+		DBG_ERR("Failed to set credentials keytab name\n");
+		goto done;
+	}
+
+	status = samba_server_gensec_start(tmp_ctx,
+					   kdc->task->event_ctx,
+					   kdc->task->msg_ctx,
+					   kdc->task->lp_ctx,
+					   server_credentials,
+					   "kpasswd",
+					   &gensec_security);
+	if (!NT_STATUS_IS_OK(status)) {
+		goto done;
+	}
+
+	status = gensec_set_local_address(gensec_security, local_addr);
+	if (!NT_STATUS_IS_OK(status)) {
+		goto done;
+	}
+
+#ifndef SAMBA4_USES_HEIMDAL
+	status = gensec_set_remote_address(gensec_security, remote_addr);
+	if (!NT_STATUS_IS_OK(status)) {
+		goto done;
+	}
+#endif
+
+	/* We want the GENSEC wrap calls to generate PRIV tokens */
+	gensec_want_feature(gensec_security, GENSEC_FEATURE_SEAL);
+
+	/* Use the krb5 gesec mechanism so we can load DB modules */
+	status = gensec_start_mech_by_name(gensec_security, "krb5");
+	if (!NT_STATUS_IS_OK(status)) {
+		goto done;
+	}
+
+	/*
+	 * Accept the AP-REQ and generate the AP-REP we need for the reply
+	 *
+	 * We only allow KRB5 and make sure the backend to is RPC/IPC free.
+	 *
+	 * See gensec_krb5_update_internal() as GENSEC_SERVER.
+	 *
+	 * It allows gensec_update() not to block.
+	 *
+	 * If that changes in future we need to use
+	 * gensec_update_send/recv here!
+	 */
+	status = gensec_update(gensec_security, tmp_ctx,
+			       ap_req_blob, &ap_rep_blob);
+	if (!NT_STATUS_IS_OK(status) &&
+	    !NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
+		ap_rep_blob = data_blob_null;
+		error_code = KRB5_KPASSWD_HARDERROR;
+		error_string = talloc_asprintf(tmp_ctx,
+					       "gensec_update failed - %s\n",
+					       nt_errstr(status));
+		DBG_ERR("%s", error_string);
+		goto reply;
+	}
+
+	status = gensec_unwrap(gensec_security,
+			       tmp_ctx,
+			       &enc_data_blob,
+			       &dec_data_blob);
+	if (!NT_STATUS_IS_OK(status)) {
+		ap_rep_blob = data_blob_null;
+		error_code = KRB5_KPASSWD_HARDERROR;
+		error_string = talloc_asprintf(tmp_ctx,
+					       "gensec_unwrap failed - %s\n",
+					       nt_errstr(status));
+		DBG_ERR("%s", error_string);
+		goto reply;
+	}
+
+	code = kpasswd_handle_request(kdc,
+				      tmp_ctx,
+				      gensec_security,
+				      verno,
+				      &dec_data_blob,
+				      &kpasswd_dec_reply,
+				      &error_string);
+	if (code != 0) {
+		ap_rep_blob = data_blob_null;
+		error_code = code;
+		goto reply;
+	}
+
+	status = gensec_wrap(gensec_security,
+			     tmp_ctx,
+			     &kpasswd_dec_reply,
+			     &enc_data_blob);
+	if (!NT_STATUS_IS_OK(status)) {
+		ap_rep_blob = data_blob_null;
+		error_code = KRB5_KPASSWD_HARDERROR;
+		error_string = talloc_asprintf(tmp_ctx,
+					       "gensec_wrap failed - %s\n",
+					       nt_errstr(status));
+		DBG_ERR("%s", error_string);
+		goto reply;
+	}
+
+reply:
+	if (error_code != 0) {
+		krb5_data k_enc_data;
+		krb5_data k_dec_data;
+		const char *principal_string;
+		krb5_principal server_principal;
+
+		if (error_string == NULL) {
+			DBG_ERR("Invalid error string! This should not happen\n");
+			goto done;
+		}
+
+		ok = kpasswd_make_error_reply(tmp_ctx,
+					      error_code,
+					      error_string,
+					      &dec_data_blob);
+		if (!ok) {
+			DBG_ERR("Failed to create error reply\n");
+			goto done;
+		}
+
+		k_dec_data.length = dec_data_blob.length;
+		k_dec_data.data   = (char *)dec_data_blob.data;
+
+		principal_string = cli_credentials_get_principal(server_credentials,
+								 tmp_ctx);
+		if (principal_string == NULL) {
+			goto done;
+		}
+
+		code = smb_krb5_parse_name(kdc->smb_krb5_context->krb5_context,
+					   principal_string,
+					   &server_principal);
+		if (code != 0) {
+			DBG_ERR("Failed to create principal: %s\n",
+				error_message(code));
+			goto done;
+		}
+
+		code = smb_krb5_mk_error(kdc->smb_krb5_context->krb5_context,
+					 KRB5KDC_ERR_NONE + error_code,
+					 NULL, /* e_text */
+					 &k_dec_data,
+					 NULL, /* client */
+					 server_principal,
+					 &k_enc_data);
+		krb5_free_principal(kdc->smb_krb5_context->krb5_context,
+				    server_principal);
+		if (code != 0) {
+			DBG_ERR("Failed to create krb5 error reply: %s\n",
+				error_message(code));
+			goto done;
+		}
+
+		enc_data_blob = data_blob_talloc(tmp_ctx,
+						 k_enc_data.data,
+						 k_enc_data.length);
+		if (enc_data_blob.data == NULL) {
+			DBG_ERR("Failed to allocate memory for error reply\n");
+			goto done;
+		}
+	}
+
+	*reply = data_blob_talloc(mem_ctx,
+				  NULL,
+				  HEADER_LEN + ap_rep_blob.length + enc_data_blob.length);
+	if (reply->data == NULL) {
+		goto done;
+	}
+	RSSVAL(reply->data, 0, reply->length);
+	RSSVAL(reply->data, 2, 1);
+	RSSVAL(reply->data, 4, ap_rep_blob.length);
+	memcpy(reply->data + HEADER_LEN,
+	       ap_rep_blob.data,
+	       ap_rep_blob.length);
+	memcpy(reply->data + HEADER_LEN + ap_rep_blob.length,
+	       enc_data_blob.data,
+	       enc_data_blob.length);
+
+	rc = KDC_OK;
+done:
+	talloc_free(tmp_ctx);
+	return rc;
+}