| 1 | /*
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| 2 | Unix SMB/CIFS implementation.
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| 3 |
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| 4 | module to store/fetch session keys for the schannel server
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| 5 |
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| 6 | Copyright (C) Andrew Tridgell 2004
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| 7 | Copyright (C) Andrew Bartlett <[email protected]> 2006-2009
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| 8 |
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| 9 | This program is free software; you can redistribute it and/or modify
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| 10 | it under the terms of the GNU General Public License as published by
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| 11 | the Free Software Foundation; either version 3 of the License, or
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| 12 | (at your option) any later version.
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| 13 |
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| 14 | This program is distributed in the hope that it will be useful,
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| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 17 | GNU General Public License for more details.
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| 18 |
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| 19 | You should have received a copy of the GNU General Public License
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| 20 | along with this program. If not, see <http://www.gnu.org/licenses/>.
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| 21 | */
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| 22 |
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| 23 | #include "includes.h"
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| 24 | #include "lib/ldb/include/ldb.h"
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| 25 | #include "librpc/gen_ndr/ndr_security.h"
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| 26 | #include "ldb_wrap.h"
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| 27 | #include "../lib/util/util_ldb.h"
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| 28 | #include "libcli/auth/libcli_auth.h"
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| 29 | #include "auth/auth.h"
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| 30 | #include "param/param.h"
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| 31 | #include "auth/gensec/schannel_state.h"
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| 32 | #include "../libcli/auth/schannel_state_proto.h"
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| 33 |
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| 34 | static struct ldb_val *schannel_dom_sid_ldb_val(TALLOC_CTX *mem_ctx,
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| 35 | struct dom_sid *sid)
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| 36 | {
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| 37 | enum ndr_err_code ndr_err;
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| 38 | struct ldb_val *v;
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| 39 |
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| 40 | v = talloc(mem_ctx, struct ldb_val);
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| 41 | if (!v) return NULL;
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| 42 |
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| 43 | ndr_err = ndr_push_struct_blob(v, mem_ctx, NULL, sid,
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| 44 | (ndr_push_flags_fn_t)ndr_push_dom_sid);
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| 45 | if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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| 46 | talloc_free(v);
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| 47 | return NULL;
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| 48 | }
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| 49 |
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| 50 | return v;
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| 51 | }
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| 52 |
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| 53 | static struct dom_sid *schannel_ldb_val_dom_sid(TALLOC_CTX *mem_ctx,
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| 54 | const struct ldb_val *v)
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| 55 | {
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| 56 | enum ndr_err_code ndr_err;
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| 57 | struct dom_sid *sid;
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| 58 |
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| 59 | sid = talloc(mem_ctx, struct dom_sid);
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| 60 | if (!sid) return NULL;
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| 61 |
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| 62 | ndr_err = ndr_pull_struct_blob(v, sid, NULL, sid,
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| 63 | (ndr_pull_flags_fn_t)ndr_pull_dom_sid);
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| 64 | if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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| 65 | talloc_free(sid);
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| 66 | return NULL;
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| 67 | }
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| 68 | return sid;
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| 69 | }
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| 70 |
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| 71 |
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| 72 | /*
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| 73 | remember an established session key for a netr server authentication
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| 74 | use a simple ldb structure
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| 75 | */
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| 76 | NTSTATUS schannel_store_session_key_ldb(struct ldb_context *ldb,
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| 77 | TALLOC_CTX *mem_ctx,
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| 78 | struct netlogon_creds_CredentialState *creds)
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| 79 | {
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| 80 | struct ldb_message *msg;
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| 81 | struct ldb_val val, seed, client_state, server_state;
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| 82 | struct ldb_val *sid_val;
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| 83 | char *f;
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| 84 | char *sct;
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| 85 | int ret;
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| 86 |
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| 87 | f = talloc_asprintf(mem_ctx, "%u", (unsigned int)creds->negotiate_flags);
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| 88 |
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| 89 | if (f == NULL) {
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| 90 | return NT_STATUS_NO_MEMORY;
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| 91 | }
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| 92 |
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| 93 | sct = talloc_asprintf(mem_ctx, "%u", (unsigned int)creds->secure_channel_type);
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| 94 |
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| 95 | if (sct == NULL) {
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| 96 | return NT_STATUS_NO_MEMORY;
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| 97 | }
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| 98 |
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| 99 | msg = ldb_msg_new(ldb);
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| 100 | if (msg == NULL) {
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| 101 | return NT_STATUS_NO_MEMORY;
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| 102 | }
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| 103 |
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| 104 | msg->dn = ldb_dn_new_fmt(msg, ldb, "computerName=%s", creds->computer_name);
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| 105 | if ( ! msg->dn) {
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| 106 | return NT_STATUS_NO_MEMORY;
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| 107 | }
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| 108 |
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| 109 | sid_val = schannel_dom_sid_ldb_val(msg, creds->sid);
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| 110 | if (sid_val == NULL) {
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| 111 | return NT_STATUS_NO_MEMORY;
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| 112 | }
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| 113 |
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| 114 | val.data = creds->session_key;
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| 115 | val.length = sizeof(creds->session_key);
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| 116 |
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| 117 | seed.data = creds->seed.data;
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| 118 | seed.length = sizeof(creds->seed.data);
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| 119 |
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| 120 | client_state.data = creds->client.data;
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| 121 | client_state.length = sizeof(creds->client.data);
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| 122 | server_state.data = creds->server.data;
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| 123 | server_state.length = sizeof(creds->server.data);
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| 124 |
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| 125 | ldb_msg_add_string(msg, "objectClass", "schannelState");
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| 126 | ldb_msg_add_value(msg, "sessionKey", &val, NULL);
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| 127 | ldb_msg_add_value(msg, "seed", &seed, NULL);
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| 128 | ldb_msg_add_value(msg, "clientState", &client_state, NULL);
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| 129 | ldb_msg_add_value(msg, "serverState", &server_state, NULL);
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| 130 | ldb_msg_add_string(msg, "negotiateFlags", f);
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| 131 | ldb_msg_add_string(msg, "secureChannelType", sct);
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| 132 | ldb_msg_add_string(msg, "accountName", creds->account_name);
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| 133 | ldb_msg_add_string(msg, "computerName", creds->computer_name);
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| 134 | ldb_msg_add_value(msg, "objectSid", sid_val, NULL);
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| 135 |
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| 136 | ret = ldb_add(ldb, msg);
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| 137 | if (ret == LDB_ERR_ENTRY_ALREADY_EXISTS) {
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| 138 | int i;
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| 139 | /* from samdb_replace() */
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| 140 | /* mark all the message elements as LDB_FLAG_MOD_REPLACE */
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| 141 | for (i=0;i<msg->num_elements;i++) {
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| 142 | msg->elements[i].flags = LDB_FLAG_MOD_REPLACE;
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| 143 | }
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| 144 |
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| 145 | ret = ldb_modify(ldb, msg);
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| 146 | }
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| 147 |
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| 148 | /* We don't need a transaction here, as we either add or
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| 149 | * modify records, never delete them, so it must exist */
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| 150 |
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| 151 | if (ret != LDB_SUCCESS) {
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| 152 | DEBUG(0,("Unable to add %s to session key db - %s\n",
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| 153 | ldb_dn_get_linearized(msg->dn), ldb_errstring(ldb)));
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| 154 | return NT_STATUS_INTERNAL_DB_CORRUPTION;
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| 155 | }
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| 156 |
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| 157 | return NT_STATUS_OK;
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| 158 | }
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| 159 |
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| 160 | /*
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| 161 | read back a credentials back for a computer
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| 162 | */
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| 163 | NTSTATUS schannel_fetch_session_key_ldb(struct ldb_context *ldb,
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| 164 | TALLOC_CTX *mem_ctx,
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| 165 | const char *computer_name,
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| 166 | struct netlogon_creds_CredentialState **creds)
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| 167 | {
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| 168 | struct ldb_result *res;
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| 169 | int ret;
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| 170 | const struct ldb_val *val;
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| 171 |
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| 172 | *creds = talloc_zero(mem_ctx, struct netlogon_creds_CredentialState);
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| 173 | if (!*creds) {
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| 174 | return NT_STATUS_NO_MEMORY;
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| 175 | }
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| 176 |
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| 177 | ret = ldb_search(ldb, mem_ctx, &res,
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| 178 | NULL, LDB_SCOPE_SUBTREE, NULL,
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| 179 | "(computerName=%s)", computer_name);
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| 180 | if (ret != LDB_SUCCESS) {
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| 181 | DEBUG(3,("schannel: Failed to find a record for client %s: %s\n", computer_name, ldb_errstring(ldb)));
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| 182 | return NT_STATUS_INVALID_HANDLE;
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| 183 | }
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| 184 | if (res->count != 1) {
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| 185 | DEBUG(3,("schannel: Failed to find a record for client: %s (found %d records)\n", computer_name, res->count));
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| 186 | talloc_free(res);
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| 187 | return NT_STATUS_INVALID_HANDLE;
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| 188 | }
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| 189 |
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| 190 | val = ldb_msg_find_ldb_val(res->msgs[0], "sessionKey");
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| 191 | if (val == NULL || val->length != 16) {
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| 192 | 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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| 193 | talloc_free(res);
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| 194 | return NT_STATUS_INTERNAL_ERROR;
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| 195 | }
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| 196 |
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| 197 | memcpy((*creds)->session_key, val->data, 16);
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| 198 |
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| 199 | val = ldb_msg_find_ldb_val(res->msgs[0], "seed");
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| 200 | if (val == NULL || val->length != 8) {
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| 201 | 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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| 202 | talloc_free(res);
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| 203 | return NT_STATUS_INTERNAL_ERROR;
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| 204 | }
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| 205 |
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| 206 | memcpy((*creds)->seed.data, val->data, 8);
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| 207 |
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| 208 | val = ldb_msg_find_ldb_val(res->msgs[0], "clientState");
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| 209 | if (val == NULL || val->length != 8) {
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| 210 | 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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| 211 | talloc_free(res);
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| 212 | return NT_STATUS_INTERNAL_ERROR;
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| 213 | }
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| 214 | memcpy((*creds)->client.data, val->data, 8);
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| 215 |
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| 216 | val = ldb_msg_find_ldb_val(res->msgs[0], "serverState");
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| 217 | if (val == NULL || val->length != 8) {
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| 218 | 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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| 219 | talloc_free(res);
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| 220 | return NT_STATUS_INTERNAL_ERROR;
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| 221 | }
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| 222 | memcpy((*creds)->server.data, val->data, 8);
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| 223 |
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| 224 | (*creds)->negotiate_flags = ldb_msg_find_attr_as_int(res->msgs[0], "negotiateFlags", 0);
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| 225 |
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| 226 | (*creds)->secure_channel_type = ldb_msg_find_attr_as_int(res->msgs[0], "secureChannelType", 0);
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| 227 |
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| 228 | (*creds)->account_name = talloc_strdup(*creds, ldb_msg_find_attr_as_string(res->msgs[0], "accountName", NULL));
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| 229 | if ((*creds)->account_name == NULL) {
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| 230 | talloc_free(res);
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| 231 | return NT_STATUS_NO_MEMORY;
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| 232 | }
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| 233 |
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| 234 | (*creds)->computer_name = talloc_strdup(*creds, ldb_msg_find_attr_as_string(res->msgs[0], "computerName", NULL));
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| 235 | if ((*creds)->computer_name == NULL) {
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| 236 | talloc_free(res);
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| 237 | return NT_STATUS_NO_MEMORY;
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| 238 | }
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| 239 |
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| 240 | val = ldb_msg_find_ldb_val(res->msgs[0], "objectSid");
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| 241 | if (val) {
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| 242 | (*creds)->sid = schannel_ldb_val_dom_sid(*creds, val);
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| 243 | if ((*creds)->sid == NULL) {
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| 244 | talloc_free(res);
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| 245 | return NT_STATUS_INTERNAL_ERROR;
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| 246 | }
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| 247 | } else {
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| 248 | (*creds)->sid = NULL;
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| 249 | }
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| 250 |
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| 251 | talloc_free(res);
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| 252 | return NT_STATUS_OK;
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| 253 | }
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| 254 |
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| 255 | /*
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| 256 | Validate an incoming authenticator against the credentials for the remote machine.
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| 257 |
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| 258 | The credentials are (re)read and from the schannel database, and
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| 259 | written back after the caclulations are performed.
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| 260 |
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| 261 | The creds_out parameter (if not NULL) returns the credentials, if
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| 262 | the caller needs some of that information.
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| 263 |
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| 264 | */
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| 265 | NTSTATUS schannel_creds_server_step_check_ldb(struct ldb_context *ldb,
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| 266 | TALLOC_CTX *mem_ctx,
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| 267 | const char *computer_name,
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| 268 | bool schannel_required_for_call,
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| 269 | bool schannel_in_use,
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| 270 | struct netr_Authenticator *received_authenticator,
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| 271 | struct netr_Authenticator *return_authenticator,
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| 272 | struct netlogon_creds_CredentialState **creds_out)
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| 273 | {
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| 274 | struct netlogon_creds_CredentialState *creds;
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| 275 | NTSTATUS nt_status;
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| 276 | int ret;
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| 277 |
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| 278 | ret = ldb_transaction_start(ldb);
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| 279 | if (ret != 0) {
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| 280 | return NT_STATUS_INTERNAL_DB_CORRUPTION;
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| 281 | }
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| 282 |
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| 283 | /* Because this is a shared structure (even across
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| 284 | * disconnects) we must update the database every time we
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| 285 | * update the structure */
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| 286 |
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| 287 | nt_status = schannel_fetch_session_key_ldb(ldb, ldb, computer_name,
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| 288 | &creds);
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| 289 |
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| 290 | /* If we are flaged that schannel is required for a call, and
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| 291 | * it is not in use, then make this an error */
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| 292 |
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| 293 | /* It would be good to make this mandetory once schannel is
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| 294 | * negoiated, bu this is not what windows does */
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| 295 | if (schannel_required_for_call && !schannel_in_use) {
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| 296 | DEBUG(0,("schannel_creds_server_step_check: client %s not using schannel for netlogon, despite negotiating it\n",
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| 297 | creds->computer_name ));
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| 298 | ldb_transaction_cancel(ldb);
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| 299 | return NT_STATUS_ACCESS_DENIED;
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| 300 | }
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| 301 |
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| 302 | if (NT_STATUS_IS_OK(nt_status)) {
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| 303 | nt_status = netlogon_creds_server_step_check(creds,
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| 304 | received_authenticator,
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| 305 | return_authenticator);
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| 306 | }
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| 307 |
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| 308 | if (NT_STATUS_IS_OK(nt_status)) {
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| 309 | nt_status = schannel_store_session_key_ldb(ldb, mem_ctx, creds);
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| 310 | }
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| 311 |
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| 312 | if (NT_STATUS_IS_OK(nt_status)) {
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| 313 | ldb_transaction_commit(ldb);
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| 314 | if (creds_out) {
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| 315 | *creds_out = creds;
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| 316 | talloc_steal(mem_ctx, creds);
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| 317 | }
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| 318 | } else {
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| 319 | ldb_transaction_cancel(ldb);
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| 320 | }
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| 321 | return nt_status;
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| 322 | }
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