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https://github.com/samba-team/samba.git
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8e2f5fe7c5
Make the initial schannel check logic more understandable. Make it easy to define different policies depending on the caller's security requirements (Integrity/Privacy/Both/None) This is the same change applied to s3
325 lines
9.3 KiB
C
325 lines
9.3 KiB
C
/*
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Unix SMB/CIFS implementation.
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module to store/fetch session keys for the schannel server
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Copyright (C) Andrew Tridgell 2004
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Copyright (C) Andrew Bartlett <abartlet@samba.org> 2006-2009
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "includes.h"
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#include "lib/ldb/include/ldb.h"
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#include "librpc/gen_ndr/ndr_security.h"
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#include "ldb_wrap.h"
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#include "../lib/util/util_ldb.h"
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#include "libcli/auth/libcli_auth.h"
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#include "auth/auth.h"
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#include "param/param.h"
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#include "../libcli/auth/schannel_state.h"
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static struct ldb_val *schannel_dom_sid_ldb_val(TALLOC_CTX *mem_ctx,
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struct dom_sid *sid)
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{
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enum ndr_err_code ndr_err;
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struct ldb_val *v;
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v = talloc(mem_ctx, struct ldb_val);
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if (!v) return NULL;
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ndr_err = ndr_push_struct_blob(v, mem_ctx, NULL, sid,
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(ndr_push_flags_fn_t)ndr_push_dom_sid);
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if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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talloc_free(v);
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return NULL;
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}
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return v;
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}
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static struct dom_sid *schannel_ldb_val_dom_sid(TALLOC_CTX *mem_ctx,
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const struct ldb_val *v)
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{
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enum ndr_err_code ndr_err;
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struct dom_sid *sid;
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sid = talloc(mem_ctx, struct dom_sid);
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if (!sid) return NULL;
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ndr_err = ndr_pull_struct_blob(v, sid, NULL, sid,
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(ndr_pull_flags_fn_t)ndr_pull_dom_sid);
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if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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talloc_free(sid);
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return NULL;
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}
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return sid;
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}
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/*
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remember an established session key for a netr server authentication
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use a simple ldb structure
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*/
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NTSTATUS schannel_store_session_key_ldb(struct ldb_context *ldb,
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TALLOC_CTX *mem_ctx,
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struct netlogon_creds_CredentialState *creds)
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{
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struct ldb_message *msg;
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struct ldb_val val, seed, client_state, server_state;
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struct ldb_val *sid_val;
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char *f;
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char *sct;
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int ret;
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f = talloc_asprintf(mem_ctx, "%u", (unsigned int)creds->negotiate_flags);
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if (f == NULL) {
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return NT_STATUS_NO_MEMORY;
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}
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sct = talloc_asprintf(mem_ctx, "%u", (unsigned int)creds->secure_channel_type);
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if (sct == NULL) {
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return NT_STATUS_NO_MEMORY;
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}
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msg = ldb_msg_new(mem_ctx);
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if (msg == NULL) {
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return NT_STATUS_NO_MEMORY;
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}
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msg->dn = ldb_dn_new_fmt(msg, ldb, "computerName=%s", creds->computer_name);
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if ( ! msg->dn) {
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return NT_STATUS_NO_MEMORY;
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}
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sid_val = schannel_dom_sid_ldb_val(msg, creds->sid);
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if (sid_val == NULL) {
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return NT_STATUS_NO_MEMORY;
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}
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val.data = creds->session_key;
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val.length = sizeof(creds->session_key);
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seed.data = creds->seed.data;
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seed.length = sizeof(creds->seed.data);
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client_state.data = creds->client.data;
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client_state.length = sizeof(creds->client.data);
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server_state.data = creds->server.data;
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server_state.length = sizeof(creds->server.data);
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ldb_msg_add_string(msg, "objectClass", "schannelState");
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ldb_msg_add_value(msg, "sessionKey", &val, NULL);
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ldb_msg_add_value(msg, "seed", &seed, NULL);
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ldb_msg_add_value(msg, "clientState", &client_state, NULL);
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ldb_msg_add_value(msg, "serverState", &server_state, NULL);
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ldb_msg_add_string(msg, "negotiateFlags", f);
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ldb_msg_add_string(msg, "secureChannelType", sct);
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ldb_msg_add_string(msg, "accountName", creds->account_name);
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ldb_msg_add_string(msg, "computerName", creds->computer_name);
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ldb_msg_add_value(msg, "objectSid", sid_val, NULL);
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ret = ldb_add(ldb, msg);
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if (ret == LDB_ERR_ENTRY_ALREADY_EXISTS) {
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int i;
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/* from samdb_replace() */
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/* mark all the message elements as LDB_FLAG_MOD_REPLACE */
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for (i=0;i<msg->num_elements;i++) {
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msg->elements[i].flags = LDB_FLAG_MOD_REPLACE;
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}
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ret = ldb_modify(ldb, msg);
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}
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/* We don't need a transaction here, as we either add or
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* modify records, never delete them, so it must exist */
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if (ret != LDB_SUCCESS) {
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DEBUG(0,("Unable to add %s to session key db - %s\n",
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ldb_dn_get_linearized(msg->dn), ldb_errstring(ldb)));
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return NT_STATUS_INTERNAL_DB_CORRUPTION;
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}
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return NT_STATUS_OK;
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}
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/*
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read back a credentials back for a computer
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*/
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NTSTATUS schannel_fetch_session_key_ldb(struct ldb_context *ldb,
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TALLOC_CTX *mem_ctx,
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const char *computer_name,
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struct netlogon_creds_CredentialState **creds)
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{
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struct ldb_result *res;
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int ret;
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const struct ldb_val *val;
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*creds = talloc_zero(mem_ctx, struct netlogon_creds_CredentialState);
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if (!*creds) {
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return NT_STATUS_NO_MEMORY;
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}
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ret = ldb_search(ldb, mem_ctx, &res,
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NULL, LDB_SCOPE_SUBTREE, NULL,
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"(computerName=%s)", computer_name);
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if (ret != LDB_SUCCESS) {
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DEBUG(3,("schannel: Failed to find a record for client %s: %s\n", computer_name, ldb_errstring(ldb)));
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return NT_STATUS_INVALID_HANDLE;
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}
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if (res->count != 1) {
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DEBUG(3,("schannel: Failed to find a record for client: %s (found %d records)\n", computer_name, res->count));
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talloc_free(res);
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return NT_STATUS_INVALID_HANDLE;
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}
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val = ldb_msg_find_ldb_val(res->msgs[0], "sessionKey");
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if (val == NULL || val->length != 16) {
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DEBUG(1,("schannel: record in schannel DB must contain a sessionKey of length 16, when searching for client: %s\n", computer_name));
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talloc_free(res);
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return NT_STATUS_INTERNAL_ERROR;
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}
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memcpy((*creds)->session_key, val->data, 16);
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val = ldb_msg_find_ldb_val(res->msgs[0], "seed");
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if (val == NULL || val->length != 8) {
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DEBUG(1,("schannel: record in schannel DB must contain a vaid seed of length 8, when searching for client: %s\n", computer_name));
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talloc_free(res);
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return NT_STATUS_INTERNAL_ERROR;
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}
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memcpy((*creds)->seed.data, val->data, 8);
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val = ldb_msg_find_ldb_val(res->msgs[0], "clientState");
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if (val == NULL || val->length != 8) {
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DEBUG(1,("schannel: record in schannel DB must contain a vaid clientState of length 8, when searching for client: %s\n", computer_name));
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talloc_free(res);
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return NT_STATUS_INTERNAL_ERROR;
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}
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memcpy((*creds)->client.data, val->data, 8);
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val = ldb_msg_find_ldb_val(res->msgs[0], "serverState");
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if (val == NULL || val->length != 8) {
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DEBUG(1,("schannel: record in schannel DB must contain a vaid serverState of length 8, when searching for client: %s\n", computer_name));
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talloc_free(res);
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return NT_STATUS_INTERNAL_ERROR;
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}
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memcpy((*creds)->server.data, val->data, 8);
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(*creds)->negotiate_flags = ldb_msg_find_attr_as_int(res->msgs[0], "negotiateFlags", 0);
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(*creds)->secure_channel_type = ldb_msg_find_attr_as_int(res->msgs[0], "secureChannelType", 0);
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(*creds)->account_name = talloc_strdup(*creds, ldb_msg_find_attr_as_string(res->msgs[0], "accountName", NULL));
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if ((*creds)->account_name == NULL) {
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talloc_free(res);
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return NT_STATUS_NO_MEMORY;
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}
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(*creds)->computer_name = talloc_strdup(*creds, ldb_msg_find_attr_as_string(res->msgs[0], "computerName", NULL));
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if ((*creds)->computer_name == NULL) {
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talloc_free(res);
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return NT_STATUS_NO_MEMORY;
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}
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val = ldb_msg_find_ldb_val(res->msgs[0], "objectSid");
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if (val) {
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(*creds)->sid = schannel_ldb_val_dom_sid(*creds, val);
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if ((*creds)->sid == NULL) {
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talloc_free(res);
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return NT_STATUS_INTERNAL_ERROR;
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}
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} else {
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(*creds)->sid = NULL;
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}
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talloc_free(res);
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return NT_STATUS_OK;
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}
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/*
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Validate an incoming authenticator against the credentials for the remote machine.
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The credentials are (re)read and from the schannel database, and
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written back after the caclulations are performed.
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The creds_out parameter (if not NULL) returns the credentials, if
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the caller needs some of that information.
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*/
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NTSTATUS schannel_creds_server_step_check_ldb(struct ldb_context *ldb,
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TALLOC_CTX *mem_ctx,
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const char *computer_name,
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struct netr_Authenticator *received_authenticator,
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struct netr_Authenticator *return_authenticator,
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struct netlogon_creds_CredentialState **creds_out)
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{
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struct netlogon_creds_CredentialState *creds = NULL;
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NTSTATUS nt_status;
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int ret;
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/* If we are flaged that schannel is required for a call, and
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* it is not in use, then make this an error */
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ret = ldb_transaction_start(ldb);
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if (ret != 0) {
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return NT_STATUS_INTERNAL_DB_CORRUPTION;
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}
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/* Because this is a shared structure (even across
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* disconnects) we must update the database every time we
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* update the structure */
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nt_status = schannel_fetch_session_key_ldb(ldb, ldb, computer_name,
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&creds);
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if (!NT_STATUS_IS_OK(nt_status)) {
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ldb_transaction_cancel(ldb);
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return nt_status;
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}
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nt_status = netlogon_creds_server_step_check(creds,
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received_authenticator,
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return_authenticator);
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if (!NT_STATUS_IS_OK(nt_status)) {
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ldb_transaction_cancel(ldb);
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talloc_free(creds);
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return nt_status;
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}
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nt_status = schannel_store_session_key_ldb(ldb, mem_ctx, creds);
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if (!NT_STATUS_IS_OK(nt_status)) {
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ldb_transaction_cancel(ldb);
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talloc_free(creds);
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return nt_status;
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}
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ldb_transaction_commit(ldb);
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if (ret != 0) {
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talloc_free(creds);
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return NT_STATUS_INTERNAL_DB_CORRUPTION;
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}
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if (creds_out) {
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*creds_out = creds;
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talloc_steal(mem_ctx, creds);
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} else {
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talloc_free(creds);
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}
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return NT_STATUS_OK;
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}
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