Add netlogond auth method

This authenticates against a local running samba4 using SamLogonEx. We retrieve
the machine password using samba4's mymachinepwd script and store the schannel
key for re-use in secrets.tdb.

1 files changed, 321 insertions, 0 deletions

diff --git a/source3/auth/auth_netlogond.c b/source3/auth/auth_netlogond.c
new file mode 100644
index 0000000000..a57f3b74a3
--- /dev/null
+++ b/source3/auth/auth_netlogond.c
@@ -0,0 +1,321 @@
+/*
+   Unix SMB/CIFS implementation.
+   Authenticate against a netlogon pipe listening on a unix domain socket
+   Copyright (C) Volker Lendecke 2008
+
+   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"
+
+#undef DBGC_CLASS
+#define DBGC_CLASS DBGC_AUTH
+
+static NTSTATUS netlogond_validate(TALLOC_CTX *mem_ctx,
+				   const struct auth_context *auth_context,
+				   const char *ncalrpc_sockname,
+				   uint8_t schannel_key[16],
+				   const auth_usersupplied_info *user_info,
+				   struct netr_SamInfo3 **pinfo3,
+				   NTSTATUS *schannel_bind_result)
+{
+	struct rpc_pipe_client *p;
+	struct cli_pipe_auth_data *auth;
+	struct netr_SamInfo3 *info3 = NULL;
+	NTSTATUS status;
+
+	*schannel_bind_result = NT_STATUS_OK;
+
+	status = rpc_pipe_open_ncalrpc(talloc_tos(), ncalrpc_sockname,
+				       &ndr_table_netlogon.syntax_id, &p);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(10, ("rpc_pipe_open_ncalrpc failed: %s\n",
+			   nt_errstr(status)));
+		return status;
+	}
+
+	status = rpccli_schannel_bind_data(p, lp_workgroup(),
+					   PIPE_AUTH_LEVEL_PRIVACY,
+					   schannel_key, &auth);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(10, ("rpccli_schannel_bind_data failed: %s\n",
+			   nt_errstr(status)));
+		TALLOC_FREE(p);
+		return status;
+	}
+
+	status = rpc_pipe_bind(p, auth);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(10, ("rpc_pipe_bind failed: %s\n", nt_errstr(status)));
+		TALLOC_FREE(p);
+		*schannel_bind_result = status;
+		return status;
+	}
+
+	/*
+	 * We have to fake a struct dcinfo, so that
+	 * rpccli_netlogon_sam_network_logon_ex can decrypt the session keys.
+	 */
+
+	p->dc = talloc(p, struct dcinfo);
+	if (p->dc == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		TALLOC_FREE(p);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	memcpy(p->dc->sess_key, schannel_key, 16);
+
+	status = rpccli_netlogon_sam_network_logon_ex(
+		p, p,
+		user_info->logon_parameters,/* flags such as 'allow
+					     * workstation logon' */
+		global_myname(),            /* server name */
+		user_info->smb_name,        /* user name logging on. */
+		user_info->client_domain,   /* domain name */
+		user_info->wksta_name,      /* workstation name */
+		(uchar *)auth_context->challenge.data, /* 8 byte challenge. */
+		user_info->lm_resp,         /* lanman 24 byte response */
+		user_info->nt_resp,         /* nt 24 byte response */
+		&info3);                    /* info3 out */
+
+	DEBUG(10, ("rpccli_netlogon_sam_network_logon_ex returned %s\n",
+		   nt_errstr(status)));
+
+	if (!NT_STATUS_IS_OK(status)) {
+		TALLOC_FREE(p);
+		return status;
+	}
+
+	*pinfo3 = talloc_move(mem_ctx, &info3);
+
+	TALLOC_FREE(p);
+	return NT_STATUS_OK;
+}
+
+static char *mymachinepw(TALLOC_CTX *mem_ctx)
+{
+	fstring pwd;
+	const char *script;
+	char *to_free = NULL;
+	ssize_t nread;
+	int ret, fd;
+
+	script = lp_parm_const_string(
+		GLOBAL_SECTION_SNUM, "auth_netlogond", "machinepwscript",
+		NULL);
+
+	if (script == NULL) {
+		to_free = talloc_asprintf(talloc_tos(), "%s/%s",
+					  get_dyn_SBINDIR(), "mymachinepw");
+		script = to_free;
+	}
+	if (script == NULL) {
+		return NULL;
+	}
+
+	ret = smbrun(script, &fd);
+	DEBUG(ret ? 0 : 3, ("mymachinepw: Running the command `%s' gave %d\n",
+			    script, ret));
+	TALLOC_FREE(to_free);
+
+	if (ret != 0) {
+		return NULL;
+	}
+
+	pwd[sizeof(pwd)-1] = '\0';
+
+	nread = read(fd, pwd, sizeof(pwd)-1);
+	close(fd);
+
+	if (nread <= 0) {
+		DEBUG(3, ("mymachinepwd: Could not read password\n"));
+		return NULL;
+	}
+
+	DEBUG(0, ("pwd: %d [%s]\n", (int)nread, pwd));
+
+	if (pwd[nread-1] == '\n') {
+		pwd[nread-1] = '\0';
+	}
+
+	return talloc_strdup(mem_ctx, pwd);
+}
+
+static NTSTATUS check_netlogond_security(const struct auth_context *auth_context,
+					 void *my_private_data,
+					 TALLOC_CTX *mem_ctx,
+					 const auth_usersupplied_info *user_info,
+					 auth_serversupplied_info **server_info)
+{
+	TALLOC_CTX *frame = talloc_stackframe();
+	struct netr_SamInfo3 *info3 = NULL;
+	struct rpc_pipe_client *p;
+	struct cli_pipe_auth_data *auth;
+	uint32_t neg_flags = NETLOGON_NEG_AUTH2_ADS_FLAGS;
+	char *plaintext_machinepw;
+	uint8_t machine_password[16];
+	uint8_t schannel_key[16];
+	NTSTATUS schannel_bind_result, status;
+	struct named_mutex *mutex;
+	const char *ncalrpcsock;
+
+	ncalrpcsock = lp_parm_const_string(
+		GLOBAL_SECTION_SNUM, "auth_netlogond", "socket", NULL);
+
+	if (ncalrpcsock == NULL) {
+		ncalrpcsock = talloc_asprintf(talloc_tos(), "%s/%s",
+					      get_dyn_NCALRPCDIR(), "DEFAULT");
+	}
+
+	if (ncalrpcsock == NULL) {
+		status = NT_STATUS_NO_MEMORY;
+		goto done;
+	}
+
+	if (!secrets_fetch_local_schannel_key(schannel_key)) {
+		goto new_key;
+	}
+
+	status = netlogond_validate(talloc_tos(), auth_context, ncalrpcsock,
+				    schannel_key, user_info, &info3,
+				    &schannel_bind_result);
+
+	DEBUG(10, ("netlogond_validate returned %s\n", nt_errstr(status)));
+
+	if (NT_STATUS_IS_OK(status)) {
+		goto okay;
+	}
+
+	if (NT_STATUS_IS_OK(schannel_bind_result)) {
+		/*
+		 * This is a real failure from the DC
+		 */
+		goto done;
+	}
+
+ new_key:
+
+	mutex = grab_named_mutex(talloc_tos(), "LOCAL_SCHANNEL_KEY", 60);
+	if (mutex == NULL) {
+		DEBUG(10, ("Could not get mutex LOCAL_SCHANNEL_KEY\n"));
+		status = NT_STATUS_ACCESS_DENIED;
+		goto done;
+	}
+
+	DEBUG(10, ("schannel bind failed, setting up new key\n"));
+
+	status = rpc_pipe_open_ncalrpc(talloc_tos(), ncalrpcsock,
+				       &ndr_table_netlogon.syntax_id, &p);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(10, ("rpc_pipe_open_ncalrpc failed: %s\n",
+			   nt_errstr(status)));
+		goto done;
+	}
+
+	status = rpccli_anon_bind_data(p, &auth);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(10, ("rpccli_anon_bind_data failed: %s\n",
+			   nt_errstr(status)));
+		goto done;
+	}
+
+	status = rpc_pipe_bind(p, auth);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(10, ("rpc_pipe_bind failed: %s\n", nt_errstr(status)));
+		goto done;
+	}
+
+	TALLOC_FREE(auth);
+
+	plaintext_machinepw = mymachinepw(talloc_tos());
+	if (plaintext_machinepw == NULL) {
+		status = NT_STATUS_NO_MEMORY;
+		goto done;
+	}
+
+	E_md4hash(plaintext_machinepw, machine_password);
+
+	TALLOC_FREE(plaintext_machinepw);
+
+	status = rpccli_netlogon_setup_creds(
+		p, global_myname(), lp_workgroup(), global_myname(),
+		global_myname(), machine_password, SEC_CHAN_BDC, &neg_flags);
+
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(10, ("rpccli_netlogon_setup_creds failed: %s\n",
+			   nt_errstr(status)));
+		goto done;
+	}
+
+	memcpy(schannel_key, p->dc->sess_key, 16);
+	secrets_store_local_schannel_key(schannel_key);
+
+	TALLOC_FREE(p);
+
+	/*
+	 * Retry the authentication with the mutex held. This way nobody else
+	 * can step on our toes.
+	 */
+
+	status = netlogond_validate(talloc_tos(), auth_context, ncalrpcsock,
+				    schannel_key, user_info, &info3,
+				    &schannel_bind_result);
+
+	DEBUG(10, ("netlogond_validate returned %s\n", nt_errstr(status)));
+
+	if (!NT_STATUS_IS_OK(status)) {
+		goto done;
+	}
+
+ okay:
+
+	status = make_server_info_info3(mem_ctx, user_info->smb_name,
+					user_info->domain, server_info,
+					info3);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(10, ("make_server_info_info3 failed: %s\n",
+			   nt_errstr(status)));
+		TALLOC_FREE(frame);
+		return status;
+	}
+
+	status = NT_STATUS_OK;
+
+ done:
+	TALLOC_FREE(frame);
+	return status;
+}
+
+/* module initialisation */
+static NTSTATUS auth_init_netlogond(struct auth_context *auth_context,
+				    const char *param,
+				    auth_methods **auth_method)
+{
+	if (!make_auth_methods(auth_context, auth_method)) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	(*auth_method)->name = "netlogond";
+	(*auth_method)->auth = check_netlogond_security;
+	return NT_STATUS_OK;
+}
+
+NTSTATUS auth_netlogond_init(void)
+{
+	smb_register_auth(AUTH_INTERFACE_VERSION, "netlogond",
+			  auth_init_netlogond);
+	return NT_STATUS_OK;
+}