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[Samba.git] / source3 / libsmb / trusts_util.c

/*
 *  Unix SMB/CIFS implementation.
 *  Routines to operate on various trust relationships
 *  Copyright (C) Andrew Bartlett                   2001
 *  Copyright (C) Rafal Szczesniak                  2003
 *
 *  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 "../libcli/auth/libcli_auth.h"
#include "../libcli/auth/netlogon_creds_cli.h"
#include "rpc_client/cli_netlogon.h"
#include "rpc_client/cli_pipe.h"
#include "../librpc/gen_ndr/ndr_netlogon.h"
#include "librpc/gen_ndr/secrets.h"
#include "secrets.h"
#include "passdb.h"
#include "libsmb/libsmb.h"
#include "source3/include/messages.h"
#include "source3/include/g_lock.h"

/*********************************************************
 Change the domain password on the PDC.
 Do most of the legwork ourselfs.  Caller must have
 already setup the connection to the NETLOGON pipe
**********************************************************/

struct trust_pw_change_state {
        struct g_lock_ctx *g_ctx;
        char *g_lock_key;
};

static int trust_pw_change_state_destructor(struct trust_pw_change_state *state)
{
        g_lock_unlock(state->g_ctx, state->g_lock_key);
        return 0;
}

char *trust_pw_new_value(TALLOC_CTX *mem_ctx,
                         enum netr_SchannelType sec_channel_type,
                         int security)
{
        /*
         * use secure defaults.
         */
        size_t min = 128;
        size_t max = 255;

        switch (sec_channel_type) {
        case SEC_CHAN_WKSTA:
        case SEC_CHAN_BDC:
                if (security == SEC_DOMAIN) {
                        /*
                         * The maximum length of a trust account password.
                         * Used when we randomly create it, 15 char passwords
                         * exceed NT4's max password length.
                         */
                        min = 14;
                        max = 14;
                }
                break;
        case SEC_CHAN_DNS_DOMAIN:
                /*
                 * new_len * 2 = 498 bytes is the largest possible length
                 * NL_PASSWORD_VERSION consumes the rest of the possible 512 bytes
                 * and a confounder with at least 2 bytes is required.
                 *
                 * Windows uses new_len = 120 => 240 bytes (utf16)
                 */
                min = 120;
                max = 120;
                break;
                /* fall through */
        case SEC_CHAN_DOMAIN:
                /*
                 * The maximum length of a trust account password.
                 * Used when we randomly create it, 15 char passwords
                 * exceed NT4's max password length.
                 */
                min = 14;
                max = 14;
                break;
        default:
                break;
        }

        /*
         * Create a random machine account password
         * We create a random buffer and convert that to utf8.
         * This is similar to what windows is doing.
         */
        return generate_random_machine_password(mem_ctx, min, max);
}

NTSTATUS trust_pw_change(struct netlogon_creds_cli_context *context,
                         struct messaging_context *msg_ctx,
                         struct dcerpc_binding_handle *b,
                         const char *domain,
                         const char *dcname,
                         bool force)
{
        TALLOC_CTX *frame = talloc_stackframe();
        const char *context_name = NULL;
        struct trust_pw_change_state *state;
        struct cli_credentials *creds = NULL;
        struct secrets_domain_info1 *info = NULL;
        struct secrets_domain_info1_change *prev = NULL;
        const struct samr_Password *current_nt_hash = NULL;
        const struct samr_Password *previous_nt_hash = NULL;
        uint8_t num_nt_hashes = 0;
        uint8_t idx = 0;
        const struct samr_Password *nt_hashes[1+3] = { NULL, };
        uint8_t idx_nt_hashes = 0;
        uint8_t idx_current = UINT8_MAX;
        enum netr_SchannelType sec_channel_type = SEC_CHAN_NULL;
        time_t pass_last_set_time;
        uint32_t old_version = 0;
        struct pdb_trusted_domain *td = NULL;
        struct timeval g_timeout = { 0, };
        int timeout = 0;
        struct timeval tv = { 0, };
        char *new_trust_pw_str = NULL;
        size_t len = 0;
        DATA_BLOB new_trust_pw_blob = data_blob_null;
        uint32_t new_version = 0;
        uint32_t *new_trust_version = NULL;
        NTSTATUS status;
        bool ok;

        state = talloc_zero(frame, struct trust_pw_change_state);
        if (state == NULL) {
                TALLOC_FREE(frame);
                return NT_STATUS_NO_MEMORY;
        }

        state->g_ctx = g_lock_ctx_init(state, msg_ctx);
        if (state->g_ctx == NULL) {
                TALLOC_FREE(frame);
                return NT_STATUS_NO_MEMORY;
        }

        state->g_lock_key = talloc_asprintf(state,
                                "trust_password_change_%s",
                                domain);
        if (state->g_lock_key == NULL) {
                TALLOC_FREE(frame);
                return NT_STATUS_NO_MEMORY;
        }

        g_timeout = timeval_current_ofs(10, 0);
        status = g_lock_lock(state->g_ctx,
                             state->g_lock_key,
                             G_LOCK_WRITE, g_timeout);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(1, ("could not get g_lock on [%s]!\n",
                          state->g_lock_key));
                TALLOC_FREE(frame);
                return status;
        }

        talloc_set_destructor(state, trust_pw_change_state_destructor);

        status = pdb_get_trust_credentials(domain, NULL, frame, &creds);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("could not fetch domain creds for domain %s - %s!\n",
                          domain, nt_errstr(status)));
                TALLOC_FREE(frame);
                return NT_STATUS_TRUSTED_RELATIONSHIP_FAILURE;
        }

        current_nt_hash = cli_credentials_get_nt_hash(creds, frame);
        if (current_nt_hash == NULL) {
                DEBUG(0, ("cli_credentials_get_nt_hash failed for domain %s!\n",
                          domain));
                TALLOC_FREE(frame);
                return NT_STATUS_TRUSTED_RELATIONSHIP_FAILURE;
        }
        previous_nt_hash = cli_credentials_get_old_nt_hash(creds, frame);

        old_version = cli_credentials_get_kvno(creds);
        pass_last_set_time = cli_credentials_get_password_last_changed_time(creds);
        sec_channel_type = cli_credentials_get_secure_channel_type(creds);

        new_version = old_version + 1;

        switch (sec_channel_type) {
        case SEC_CHAN_WKSTA:
        case SEC_CHAN_BDC:
                break;
        case SEC_CHAN_DNS_DOMAIN:
        case SEC_CHAN_DOMAIN:
                status = pdb_get_trusted_domain(frame, domain, &td);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("pdb_get_trusted_domain() failed for domain %s - %s!\n",
                                  domain, nt_errstr(status)));
                        TALLOC_FREE(frame);
                        return status;
                }

                new_trust_version = &new_version;
                break;
        default:
                TALLOC_FREE(frame);
                return NT_STATUS_NOT_SUPPORTED;
        }

        timeout = lp_machine_password_timeout();
        if (timeout == 0) {
                if (!force) {
                        DEBUG(10,("machine password never expires\n"));
                        TALLOC_FREE(frame);
                        return NT_STATUS_OK;
                }
        }

        tv.tv_sec = pass_last_set_time;
        DEBUG(10, ("password last changed %s\n",
                   timeval_string(talloc_tos(), &tv, false)));
        tv.tv_sec += timeout;
        DEBUGADD(10, ("password valid until %s\n",
                      timeval_string(talloc_tos(), &tv, false)));

        if (!force && !timeval_expired(&tv)) {
                TALLOC_FREE(frame);
                return NT_STATUS_OK;
        }

        context_name = netlogon_creds_cli_debug_string(context, talloc_tos());
        if (context_name == NULL) {
                TALLOC_FREE(frame);
                return NT_STATUS_NO_MEMORY;
        }

        /*
         * Create a random machine account password
         * We create a random buffer and convert that to utf8.
         * This is similar to what windows is doing.
         */
        new_trust_pw_str = trust_pw_new_value(frame, sec_channel_type,
                                              lp_security());
        if (new_trust_pw_str == NULL) {
                DEBUG(0, ("trust_pw_new_value() failed\n"));
                TALLOC_FREE(frame);
                return NT_STATUS_NO_MEMORY;
        }

        len = strlen(new_trust_pw_str);
        ok = convert_string_talloc(frame, CH_UNIX, CH_UTF16,
                                   new_trust_pw_str, len,
                                   (void **)&new_trust_pw_blob.data,
                                   &new_trust_pw_blob.length);
        if (!ok) {
                status = NT_STATUS_UNMAPPABLE_CHARACTER;
                if (errno == ENOMEM) {
                        status = NT_STATUS_NO_MEMORY;
                }
                DBG_ERR("convert_string_talloc(CH_UTF16MUNGED, CH_UNIX) "
                        "failed for of %s - %s\n",
                        domain, nt_errstr(status));
                TALLOC_FREE(frame);
                return status;
        }

        switch (sec_channel_type) {

        case SEC_CHAN_WKSTA:
        case SEC_CHAN_BDC:
                status = secrets_prepare_password_change(domain, dcname,
                                                         new_trust_pw_str,
                                                         frame, &info, &prev);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("secrets_prepare_password_change() failed for domain %s!\n",
                                  domain));
                        TALLOC_FREE(frame);
                        return NT_STATUS_INTERNAL_DB_CORRUPTION;
                }
                TALLOC_FREE(new_trust_pw_str);

                if (prev != NULL) {
                        /*
                         * We had a failure before we changed the password.
                         */
                        nt_hashes[idx++] = &prev->password->nt_hash;

                        DEBUG(0,("%s : %s(%s): A password change was already "
                                 "started against '%s' at %s. Trying to "
                                 "recover...\n",
                                 current_timestring(talloc_tos(), false),
                                 __func__, domain,
                                 prev->password->change_server,
                                 nt_time_string(talloc_tos(),
                                 prev->password->change_time)));
                        DEBUG(0,("%s : %s(%s): Last failure local[%s] remote[%s] "
                                 "against '%s' at %s.\n",
                                 current_timestring(talloc_tos(), false),
                                 __func__, domain,
                                 nt_errstr(prev->local_status),
                                 nt_errstr(prev->remote_status),
                                 prev->change_server,
                                 nt_time_string(talloc_tos(),
                                 prev->change_time)));
                }

                idx_current = idx;
                nt_hashes[idx++] = &info->password->nt_hash;
                if (info->old_password != NULL) {
                        nt_hashes[idx++] = &info->old_password->nt_hash;
                }
                if (info->older_password != NULL) {
                        nt_hashes[idx++] = &info->older_password->nt_hash;
                }

                /*
                 * We use the password that's already persitent in
                 * our database in order to handle failures.
                 */
                data_blob_clear_free(&new_trust_pw_blob);
                new_trust_pw_blob = info->next_change->password->cleartext_blob;
                break;

        case SEC_CHAN_DNS_DOMAIN:
        case SEC_CHAN_DOMAIN:
                idx_current = idx;
                nt_hashes[idx++] = current_nt_hash;
                if (previous_nt_hash != NULL) {
                        nt_hashes[idx++] = previous_nt_hash;
                }
                break;

        default:
                smb_panic("Unsupported secure channel type");
                break;
        }
        num_nt_hashes = idx;

        DEBUG(0,("%s : %s(%s): Verifying passwords remotely %s.\n",
                 current_timestring(talloc_tos(), false),
                 __func__, domain, context_name));

        /*
         * Check which password the dc knows about.
         *
         * TODO:
         * If the previous password is the only password in common with the dc,
         * we better skip the password change, or use something like
         * ServerTrustPasswordsGet() or netr_ServerGetTrustInfo() to fix our
         * local secrets before doing the change.
         */
        status = netlogon_creds_cli_auth(context, b,
                                         num_nt_hashes,
                                         nt_hashes,
                                         &idx_nt_hashes);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("netlogon_creds_cli_auth(%s) failed for old passwords (%u) - %s!\n",
                          context_name, num_nt_hashes, nt_errstr(status)));
                TALLOC_FREE(frame);
                return status;
        }

        if (prev != NULL && idx_nt_hashes == 0) {
                DEBUG(0,("%s : %s(%s): Verified new password remotely "
                         "without changing %s\n",
                         current_timestring(talloc_tos(), false),
                         __func__, domain, context_name));

                status = secrets_finish_password_change(prev->password->change_server,
                                                        prev->password->change_time,
                                                        info);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("secrets_prepare_password_change() failed for domain %s!\n",
                                  domain));
                        TALLOC_FREE(frame);
                        return NT_STATUS_INTERNAL_DB_CORRUPTION;
                }

                DEBUG(0,("%s : %s(%s): Recovered previous password change.\n",
                         current_timestring(talloc_tos(), false),
                         __func__, domain));
                TALLOC_FREE(frame);
                return NT_STATUS_OK;
        }

        if (idx_nt_hashes != idx_current) {
                DEBUG(0,("%s : %s(%s): Verified older password remotely "
                         "skip changing %s\n",
                         current_timestring(talloc_tos(), false),
                         __func__, domain, context_name));

                if (info == NULL) {
                        TALLOC_FREE(frame);
                        return NT_STATUS_TRUSTED_RELATIONSHIP_FAILURE;
                }

                status = secrets_defer_password_change(dcname,
                                        NT_STATUS_TRUSTED_RELATIONSHIP_FAILURE,
                                        NT_STATUS_NOT_COMMITTED,
                                        info);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("secrets_defer_password_change() failed for domain %s!\n",
                                  domain));
                        TALLOC_FREE(frame);
                        return NT_STATUS_INTERNAL_DB_CORRUPTION;
                }
                TALLOC_FREE(frame);
                return NT_STATUS_TRUSTED_RELATIONSHIP_FAILURE;
        }

        DEBUG(0,("%s : %s(%s): Verified old password remotely using %s\n",
                 current_timestring(talloc_tos(), false),
                 __func__, domain, context_name));

        /*
         * Return the result of trying to write the new password
         * back into the trust account file.
         */

        switch (sec_channel_type) {

        case SEC_CHAN_WKSTA:
        case SEC_CHAN_BDC:
                /*
                 * we called secrets_prepare_password_change() above.
                 */
                break;

        case SEC_CHAN_DNS_DOMAIN:
        case SEC_CHAN_DOMAIN:
                /*
                 * we need to get the sid first for the
                 * pdb_set_trusteddom_pw call
                 */
                ok = pdb_set_trusteddom_pw(domain, new_trust_pw_str,
                                           &td->security_identifier);
                if (!ok) {
                        DEBUG(0, ("pdb_set_trusteddom_pw() failed for domain %s!\n",
                                  domain));
                        TALLOC_FREE(frame);
                        return NT_STATUS_INTERNAL_DB_CORRUPTION;
                }
                TALLOC_FREE(new_trust_pw_str);
                break;

        default:
                smb_panic("Unsupported secure channel type");
                break;
        }

        DEBUG(0,("%s : %s(%s): Changed password locally\n",
                 current_timestring(talloc_tos(), false), __func__, domain));

        status = netlogon_creds_cli_ServerPasswordSet(context, b,
                                                      &new_trust_pw_blob,
                                                      new_trust_version);
        if (!NT_STATUS_IS_OK(status)) {
                NTSTATUS status2;
                const char *fn = NULL;

                ok = dcerpc_binding_handle_is_connected(b);

                DEBUG(0,("%s : %s(%s) remote password change with %s failed "
                         "- %s (%s)\n",
                         current_timestring(talloc_tos(), false),
                         __func__, domain, context_name,
                         nt_errstr(status),
                         ok ? "connected": "disconnected"));

                if (!ok) {
                        /*
                         * The connection is broken, we don't
                         * know if the password was changed,
                         * we hope to have more luck next time.
                         */
                        status2 = secrets_failed_password_change(dcname,
                                                        NT_STATUS_NOT_COMMITTED,
                                                        status,
                                                        info);
                        fn = "secrets_failed_password_change";
                } else {
                        /*
                         * The server rejected the change, we don't
                         * retry and defer the change to the next
                         * "machine password timeout" interval.
                         */
                        status2 = secrets_defer_password_change(dcname,
                                                        NT_STATUS_NOT_COMMITTED,
                                                        status,
                                                        info);
                        fn = "secrets_defer_password_change";
                }
                if (!NT_STATUS_IS_OK(status2)) {
                        DEBUG(0, ("%s() failed for domain %s!\n",
                                  fn, domain));
                        TALLOC_FREE(frame);
                        return NT_STATUS_INTERNAL_DB_CORRUPTION;
                }

                TALLOC_FREE(frame);
                return status;
        }

        DEBUG(0,("%s : %s(%s): Changed password remotely using %s\n",
                 current_timestring(talloc_tos(), false),
                 __func__, domain, context_name));

        switch (sec_channel_type) {

        case SEC_CHAN_WKSTA:
        case SEC_CHAN_BDC:
                status = secrets_finish_password_change(
                                        info->next_change->change_server,
                                        info->next_change->change_time,
                                        info);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("secrets_finish_password_change() failed for domain %s!\n",
                                  domain));
                        TALLOC_FREE(frame);
                        return NT_STATUS_INTERNAL_DB_CORRUPTION;
                }

                DEBUG(0,("%s : %s(%s): Finished password change.\n",
                         current_timestring(talloc_tos(), false),
                         __func__, domain));
                break;

        case SEC_CHAN_DNS_DOMAIN:
        case SEC_CHAN_DOMAIN:
                /*
                 * we used pdb_set_trusteddom_pw().
                 */
                break;

        default:
                smb_panic("Unsupported secure channel type");
                break;
        }

        ok = cli_credentials_set_utf16_password(creds,
                                                &new_trust_pw_blob,
                                                CRED_SPECIFIED);
        if (!ok) {
                DEBUG(0, ("cli_credentials_set_password failed for domain %s!\n",
                          domain));
                TALLOC_FREE(frame);
                return NT_STATUS_NO_MEMORY;
        }

        current_nt_hash = cli_credentials_get_nt_hash(creds, frame);
        if (current_nt_hash == NULL) {
                DEBUG(0, ("cli_credentials_get_nt_hash failed for domain %s!\n",
                          domain));
                TALLOC_FREE(frame);
                return NT_STATUS_TRUSTED_RELATIONSHIP_FAILURE;
        }

        /*
         * Now we verify the new password.
         */
        idx = 0;
        idx_current = idx;
        nt_hashes[idx++] = current_nt_hash;
        num_nt_hashes = idx;
        status = netlogon_creds_cli_auth(context, b,
                                         num_nt_hashes,
                                         nt_hashes,
                                         &idx_nt_hashes);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("netlogon_creds_cli_auth(%s) failed for new password - %s!\n",
                          context_name, nt_errstr(status)));
                TALLOC_FREE(frame);
                return status;
        }

        DEBUG(0,("%s : %s(%s): Verified new password remotely using %s\n",
                 current_timestring(talloc_tos(), false),
                 __func__, domain, context_name));

        TALLOC_FREE(frame);
        return NT_STATUS_OK;
}