Push schannel_state.c into the top level.

This is the server side state for netlogon credential chaining

Andrew Bartlett

2 files changed, 322 insertions, 0 deletions

diff --git a/libcli/auth/config.mk b/libcli/auth/config.mk
index 5428f04433..103402099d 100644
--- a/libcli/auth/config.mk
+++ b/libcli/auth/config.mk
@@ -22,3 +22,10 @@ LIBCLI_AUTH_OBJ_FILES = $(addprefix $(libclicommonsrcdir)/auth/, \
 
 PUBLIC_HEADERS += ../libcli/auth/credentials.h
 $(eval $(call proto_header_template,$(libclicommonsrcdir)/auth/proto.h,$(LIBCLI_AUTH_OBJ_FILES:.o=.c)))
+
+[SUBSYSTEM::COMMON_SCHANNELDB]
+PRIVATE_DEPENDENCIES = LDB_WRAP
+
+COMMON_SCHANNELDB_OBJ_FILES = $(addprefix $(libclicommonsrcdir)/auth/, schannel_state.o)
+$(eval $(call proto_header_template,$(libclicommonsrcdir)/auth/schannel_state_proto.h,$(COMMON_SCHANNELDB_OBJ_FILES:.o=.c)))
+
diff --git a/libcli/auth/schannel_state.c b/libcli/auth/schannel_state.c
new file mode 100644
index 0000000000..c3f087d7dc
--- /dev/null
+++ b/libcli/auth/schannel_state.c
@@ -0,0 +1,315 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   module to store/fetch session keys for the schannel server
+
+   Copyright (C) Andrew Tridgell 2004
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2006-2009
+
+   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 "lib/ldb/include/ldb.h"
+#include "librpc/gen_ndr/ndr_security.h"
+#include "ldb_wrap.h"
+#include "../lib/util/util_ldb.h"
+#include "libcli/auth/libcli_auth.h"
+#include "auth/auth.h"
+#include "param/param.h"
+#include "auth/gensec/schannel_state.h"
+
+static struct ldb_val *schannel_dom_sid_ldb_val(TALLOC_CTX *mem_ctx,
+						struct dom_sid *sid)
+{
+	enum ndr_err_code ndr_err;
+	struct ldb_val *v;
+
+	v = talloc(mem_ctx, struct ldb_val);
+	if (!v) return NULL;
+
+	ndr_err = ndr_push_struct_blob(v, mem_ctx, NULL, sid,
+				       (ndr_push_flags_fn_t)ndr_push_dom_sid);
+	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+		talloc_free(v);
+		return NULL;
+	}
+
+	return v;
+}
+
+static struct dom_sid *schannel_ldb_val_dom_sid(TALLOC_CTX *mem_ctx,
+						 const struct ldb_val *v)
+{
+	enum ndr_err_code ndr_err;
+	struct dom_sid *sid;
+
+	sid = talloc(mem_ctx, struct dom_sid);
+	if (!sid) return NULL;
+
+	ndr_err = ndr_pull_struct_blob(v, sid, NULL, sid,
+					(ndr_pull_flags_fn_t)ndr_pull_dom_sid);
+	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+		talloc_free(sid);
+		return NULL;
+	}
+	return sid;
+}
+
+
+/*
+  remember an established session key for a netr server authentication
+  use a simple ldb structure
+*/
+NTSTATUS schannel_store_session_key(struct ldb_context *ldb,
+				    TALLOC_CTX *mem_ctx,
+				    struct netlogon_creds_CredentialState *creds)
+{
+	struct ldb_message *msg;
+	struct ldb_val val, seed, client_state, server_state;
+	struct ldb_val *sid_val;
+	char *f;
+	char *sct;
+	int ret;
+
+	f = talloc_asprintf(mem_ctx, "%u", (unsigned int)creds->negotiate_flags);
+
+	if (f == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	sct = talloc_asprintf(mem_ctx, "%u", (unsigned int)creds->secure_channel_type);
+
+	if (sct == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	msg = ldb_msg_new(ldb);
+	if (msg == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	msg->dn = ldb_dn_new_fmt(msg, ldb, "computerName=%s", creds->computer_name);
+	if ( ! msg->dn) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	sid_val = schannel_dom_sid_ldb_val(msg, creds->sid);
+	if (sid_val == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	val.data = creds->session_key;
+	val.length = sizeof(creds->session_key);
+
+	seed.data = creds->seed.data;
+	seed.length = sizeof(creds->seed.data);
+
+	client_state.data = creds->client.data;
+	client_state.length = sizeof(creds->client.data);
+	server_state.data = creds->server.data;
+	server_state.length = sizeof(creds->server.data);
+
+	ldb_msg_add_string(msg, "objectClass", "schannelState");
+	ldb_msg_add_value(msg, "sessionKey", &val, NULL);
+	ldb_msg_add_value(msg, "seed", &seed, NULL);
+	ldb_msg_add_value(msg, "clientState", &client_state, NULL);
+	ldb_msg_add_value(msg, "serverState", &server_state, NULL);
+	ldb_msg_add_string(msg, "negotiateFlags", f);
+	ldb_msg_add_string(msg, "secureChannelType", sct);
+	ldb_msg_add_string(msg, "accountName", creds->account_name);
+	ldb_msg_add_string(msg, "computerName", creds->computer_name);
+	ldb_msg_add_value(msg, "objectSid", sid_val, NULL);
+
+	ret = ldb_add(ldb, msg);
+	if (ret == LDB_ERR_ENTRY_ALREADY_EXISTS) {
+		int i;
+		/* from samdb_replace() */
+		/* mark all the message elements as LDB_FLAG_MOD_REPLACE */
+		for (i=0;i<msg->num_elements;i++) {
+			msg->elements[i].flags = LDB_FLAG_MOD_REPLACE;
+		}
+
+		ret = ldb_modify(ldb, msg);
+	}
+	
+	/* We don't need a transaction here, as we either add or
+	 * modify records, never delete them, so it must exist */
+
+	if (ret != 0) {
+		DEBUG(0,("Unable to add %s to session key db - %s\n", 
+			 ldb_dn_get_linearized(msg->dn), ldb_errstring(ldb)));
+		return NT_STATUS_INTERNAL_DB_CORRUPTION;
+	}
+
+	return NT_STATUS_OK;
+}
+
+/*
+  read back a credentials back for a computer
+*/
+NTSTATUS schannel_fetch_session_key(struct ldb_context *ldb,
+				    TALLOC_CTX *mem_ctx,
+				    const char *computer_name, 
+				    struct netlogon_creds_CredentialState **creds)
+{
+	struct ldb_result *res;
+	int ret;
+	const struct ldb_val *val;
+
+	*creds = talloc_zero(mem_ctx, struct netlogon_creds_CredentialState);
+	if (!*creds) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	ret = ldb_search(ldb, mem_ctx, &res,
+				 NULL, LDB_SCOPE_SUBTREE, NULL,
+				"(computerName=%s)", computer_name);
+	if (ret != LDB_SUCCESS) {
+		DEBUG(3,("schannel: Failed to find a record for client %s: %s\n", computer_name, ldb_errstring(ldb)));
+		return NT_STATUS_INVALID_HANDLE;
+	}
+	if (res->count != 1) {
+		DEBUG(3,("schannel: Failed to find a record for client: %s (found %d records)\n", computer_name, res->count));
+		talloc_free(res);
+		return NT_STATUS_INVALID_HANDLE;
+	}
+
+	val = ldb_msg_find_ldb_val(res->msgs[0], "sessionKey");
+	if (val == NULL || val->length != 16) {
+		DEBUG(1,("schannel: record in schannel DB must contain a sessionKey of length 16, when searching for client: %s\n", computer_name));
+		talloc_free(res);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	memcpy((*creds)->session_key, val->data, 16);
+
+	val = ldb_msg_find_ldb_val(res->msgs[0], "seed");
+	if (val == NULL || val->length != 8) {
+		DEBUG(1,("schannel: record in schannel DB must contain a vaid seed of length 8, when searching for client: %s\n", computer_name));
+		talloc_free(res);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	memcpy((*creds)->seed.data, val->data, 8);
+
+	val = ldb_msg_find_ldb_val(res->msgs[0], "clientState");
+	if (val == NULL || val->length != 8) {
+		DEBUG(1,("schannel: record in schannel DB must contain a vaid clientState of length 8, when searching for client: %s\n", computer_name));
+		talloc_free(res);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+	memcpy((*creds)->client.data, val->data, 8);
+
+	val = ldb_msg_find_ldb_val(res->msgs[0], "serverState");
+	if (val == NULL || val->length != 8) {
+		DEBUG(1,("schannel: record in schannel DB must contain a vaid serverState of length 8, when searching for client: %s\n", computer_name));
+		talloc_free(res);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+	memcpy((*creds)->server.data, val->data, 8);
+
+	(*creds)->negotiate_flags = ldb_msg_find_attr_as_int(res->msgs[0], "negotiateFlags", 0);
+
+	(*creds)->secure_channel_type = ldb_msg_find_attr_as_int(res->msgs[0], "secureChannelType", 0);
+
+	(*creds)->account_name = talloc_strdup(*creds, ldb_msg_find_attr_as_string(res->msgs[0], "accountName", NULL));
+	if ((*creds)->account_name == NULL) {
+		talloc_free(res);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	(*creds)->computer_name = talloc_strdup(*creds, ldb_msg_find_attr_as_string(res->msgs[0], "computerName", NULL));
+	if ((*creds)->computer_name == NULL) {
+		talloc_free(res);
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	val = ldb_msg_find_ldb_val(res->msgs[0], "objectSid");
+	if (val) {
+		(*creds)->sid = schannel_ldb_val_dom_sid(*creds, val);
+		if ((*creds)->sid == NULL) {
+			talloc_free(res);
+			return NT_STATUS_INTERNAL_ERROR;
+		}
+	} else {
+		(*creds)->sid = NULL;
+	}
+
+	talloc_free(res);
+	return NT_STATUS_OK;
+}
+
+/*
+  Validate an incoming authenticator against the credentials for the remote machine.
+
+  The credentials are (re)read and from the schannel database, and
+  written back after the caclulations are performed.
+
+  The creds_out parameter (if not NULL) returns the credentials, if
+  the caller needs some of that information.
+
+*/
+NTSTATUS schannel_creds_server_step_check(struct ldb_context *ldb,
+					  TALLOC_CTX *mem_ctx, 
+					  bool schannel_in_use,
+					  const char *computer_name,
+					  struct netr_Authenticator *received_authenticator,
+					  struct netr_Authenticator *return_authenticator,
+					  struct netlogon_creds_CredentialState **creds_out) 
+{
+	struct netlogon_creds_CredentialState *creds;
+	NTSTATUS nt_status;
+	int ret;
+
+	ret = ldb_transaction_start(ldb);
+	if (ret != 0) {
+		return NT_STATUS_INTERNAL_DB_CORRUPTION;
+	}
+
+	/* Because this is a shared structure (even across
+	 * disconnects) we must update the database every time we
+	 * update the structure */ 
+	
+	nt_status = schannel_fetch_session_key(ldb, ldb, computer_name, 
+					       &creds);
+
+	/* Ensure that once the client and server agree on schannel, that all future calls must use it */
+	if (creds->negotiate_flags & NETLOGON_NEG_SCHANNEL && !schannel_in_use) {
+		DEBUG(0,("schannel_creds_server_step_check: client %s not using schannel for netlogon, despite negotiating it\n",
+			creds->computer_name ));
+		return NT_STATUS_ACCESS_DENIED;
+	}
+
+	if (NT_STATUS_IS_OK(nt_status)) {
+		nt_status = netlogon_creds_server_step_check(creds, 
+							     received_authenticator, 
+							     return_authenticator);
+	}
+
+	if (NT_STATUS_IS_OK(nt_status)) {
+		nt_status = schannel_store_session_key(ldb, mem_ctx, creds);
+	}
+
+	if (NT_STATUS_IS_OK(nt_status)) {
+		ldb_transaction_commit(ldb);
+		if (creds_out) {
+			*creds_out = creds;
+			talloc_steal(mem_ctx, creds);
+		}
+	} else {
+		ldb_transaction_cancel(ldb);
+	}
+	return nt_status;
+}