/* 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 "../libcli/auth/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_ldb(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(mem_ctx); 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 != LDB_SUCCESS) { 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_ldb(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_ldb(struct ldb_context *ldb, TALLOC_CTX *mem_ctx, const char *computer_name, bool schannel_required_for_call, bool schannel_in_use, struct netr_Authenticator *received_authenticator, struct netr_Authenticator *return_authenticator, struct netlogon_creds_CredentialState **creds_out) { struct netlogon_creds_CredentialState *creds = NULL; NTSTATUS nt_status; int ret; /* If we are flaged that schannel is required for a call, and * it is not in use, then make this an error */ /* It would be good to make this mandetory once schannel is * negoiated, but this is not what windows does */ if (schannel_required_for_call && !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; } 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, ldb, computer_name, &creds); if (!NT_STATUS_IS_OK(nt_status)) { ldb_transaction_cancel(ldb); return nt_status; } nt_status = netlogon_creds_server_step_check(creds, received_authenticator, return_authenticator); if (!NT_STATUS_IS_OK(nt_status)) { ldb_transaction_cancel(ldb); talloc_free(creds); return nt_status; } nt_status = schannel_store_session_key_ldb(ldb, mem_ctx, creds); if (!NT_STATUS_IS_OK(nt_status)) { ldb_transaction_cancel(ldb); talloc_free(creds); return nt_status; } ldb_transaction_commit(ldb); if (ret != 0) { talloc_free(creds); return NT_STATUS_INTERNAL_DB_CORRUPTION; } if (creds_out) { *creds_out = creds; talloc_steal(mem_ctx, creds); } else { talloc_free(creds); } return NT_STATUS_OK; }