libmlsvc/common/mlsvc_domain.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
 */

#include <syslog.h>
#include <synch.h>
#include <pthread.h>
#include <unistd.h>
#include <string.h>
#include <strings.h>
#include <sys/errno.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include <netdb.h>
#include <assert.h>

#include <smbsrv/libsmb.h>
#include <smbsrv/libsmbns.h>
#include <smbsrv/libmlsvc.h>

#include <smbsrv/smbinfo.h>
#include <lsalib.h>
#include <mlsvc.h>

/*
 * DC Locator
 */
#define SMB_DCLOCATOR_TIMEOUT   45  /* seconds */
#define SMB_IS_FQDN(domain) (strchr(domain, '.') != NULL)

typedef struct smb_dclocator {
    smb_dcinfo_t    sdl_dci; /* .dc_name .dc_addr */
    char        sdl_domain[SMB_PI_MAX_DOMAIN];
    boolean_t   sdl_locate;
    boolean_t   sdl_bad_dc;
    boolean_t   sdl_cfg_chg;
    mutex_t     sdl_mtx;
    cond_t      sdl_cv;
    uint32_t    sdl_status;
} smb_dclocator_t;

static smb_dclocator_t smb_dclocator;
static pthread_t smb_dclocator_thr;

static void *smb_ddiscover_service(void *);
static uint32_t smb_ddiscover_qinfo(char *, char *, smb_domainex_t *);
static void smb_ddiscover_enum_trusted(char *, char *, smb_domainex_t *);
static uint32_t smb_ddiscover_use_config(char *, smb_domainex_t *);
static void smb_domainex_free(smb_domainex_t *);
static void smb_set_krb5_realm(char *);

/*
 * ===================================================================
 * API to initialize DC locator thread, trigger DC discovery, and
 * get the discovered DC and/or domain information.
 * ===================================================================
 */

/*
 * Initialization of the DC locator thread.
 * Returns 0 on success, an error number if thread creation fails.
 */
int
smb_dclocator_init(void)
{
    pthread_attr_t tattr;
    int rc;

    (void) pthread_attr_init(&tattr);
    (void) pthread_attr_setdetachstate(&tattr, PTHREAD_CREATE_DETACHED);
    rc = pthread_create(&smb_dclocator_thr, &tattr,
        smb_ddiscover_service, &smb_dclocator);
    (void) pthread_attr_destroy(&tattr);
    return (rc);
}

/*
 * This is the entry point for discovering a domain controller for the
 * specified domain.  Called during join domain, and then periodically
 * by smbd_dc_update (the "DC monitor" thread).
 *
 * The actual work of discovering a DC is handled by DC locator thread.
 * All we do here is signal the request and wait for a DC or a timeout.
 *
 * Input parameters:
 *  domain - domain to be discovered (can either be NetBIOS or DNS domain)
 *
 * Output parameter:
 *  dp - on success, dp will be filled with the discovered DC and domain
 *       information.
 *
 * Returns B_TRUE if the DC/domain info is available.
 */
boolean_t
smb_locate_dc(char *domain, smb_domainex_t *dp)
{
    int rc;
    boolean_t rv;
    timestruc_t to;
    smb_domainex_t domain_info;

    if (domain == NULL || *domain == '\0') {
        syslog(LOG_DEBUG, "smb_locate_dc NULL dom");
        smb_set_krb5_realm(NULL);
        return (B_FALSE);
    }

    (void) mutex_lock(&smb_dclocator.sdl_mtx);

    if (strcmp(smb_dclocator.sdl_domain, domain)) {
        (void) strlcpy(smb_dclocator.sdl_domain, domain,
            sizeof (smb_dclocator.sdl_domain));
        smb_dclocator.sdl_cfg_chg = B_TRUE;
        syslog(LOG_DEBUG, "smb_locate_dc new dom=%s", domain);
        smb_set_krb5_realm(domain);
    }

    if (!smb_dclocator.sdl_locate) {
        smb_dclocator.sdl_locate = B_TRUE;
        (void) cond_broadcast(&smb_dclocator.sdl_cv);
    }

    while (smb_dclocator.sdl_locate) {
        to.tv_sec = SMB_DCLOCATOR_TIMEOUT;
        to.tv_nsec = 0;
        rc = cond_reltimedwait(&smb_dclocator.sdl_cv,
            &smb_dclocator.sdl_mtx, &to);

        if (rc == ETIME) {
            syslog(LOG_NOTICE, "smb_locate_dc timeout");
            rv = B_FALSE;
            goto out;
        }
    }
    if (smb_dclocator.sdl_status != 0) {
        syslog(LOG_NOTICE, "smb_locate_dc status 0x%x",
            smb_dclocator.sdl_status);
        rv = B_FALSE;
        goto out;
    }

    if (dp == NULL)
        dp = &domain_info;
    rv = smb_domain_getinfo(dp);

out:
    (void) mutex_unlock(&smb_dclocator.sdl_mtx);

    return (rv);
}

/*
 * Tell the domain discovery service to run again now,
 * and assume changed configuration (i.e. a new DC).
 * Like the first part of smb_locate_dc().
 *
 * Note: This is called from the service refresh handler
 * and the door handler to tell the ddiscover thread to
 * request the new DC from idmap.  Therefore, we must not
 * trigger a new idmap discovery run from here, or that
 * would start a ping-pong match.
 */
/* ARGSUSED */
void
smb_ddiscover_refresh()
{

    (void) mutex_lock(&smb_dclocator.sdl_mtx);

    if (smb_dclocator.sdl_cfg_chg == B_FALSE) {
        smb_dclocator.sdl_cfg_chg = B_TRUE;
        syslog(LOG_DEBUG, "smb_ddiscover_refresh set cfg changed");
    }
    if (!smb_dclocator.sdl_locate) {
        smb_dclocator.sdl_locate = B_TRUE;
        (void) cond_broadcast(&smb_dclocator.sdl_cv);
    }

    (void) mutex_unlock(&smb_dclocator.sdl_mtx);
}

/*
 * Called by our client-side threads after they fail to connect to
 * the DC given to them by smb_locate_dc().  This is often called
 * after some delay, because the connection timeout delays these
 * threads for a while, so it's quite common that the DC locator
 * service has already started looking for a new DC.  These late
 * notifications should not continually restart the DC locator.
 */
void
smb_ddiscover_bad_dc(char *bad_dc)
{

    assert(bad_dc[0] != '\0');

    (void) mutex_lock(&smb_dclocator.sdl_mtx);

    syslog(LOG_DEBUG, "smb_ddiscover_bad_dc, cur=%s, bad=%s",
        smb_dclocator.sdl_dci.dc_name, bad_dc);

    if (strcmp(smb_dclocator.sdl_dci.dc_name, bad_dc)) {
        /*
         * The "bad" DC is no longer the current one.
         * Probably a late "bad DC" report.
         */
        goto out;
    }
    if (smb_dclocator.sdl_bad_dc) {
        /* Someone already marked the current DC as "bad". */
        syslog(LOG_DEBUG, "smb_ddiscover_bad_dc repeat");
        goto out;
    }

    /*
     * Mark the current DC as "bad" and let the DC Locator
     * run again if it's not already.
     */
    syslog(LOG_INFO, "smb_ddiscover, bad DC: %s", bad_dc);
    smb_dclocator.sdl_bad_dc = B_TRUE;

    /* In-line smb_ddiscover_kick */
    if (!smb_dclocator.sdl_locate) {
        smb_dclocator.sdl_locate = B_TRUE;
        (void) cond_broadcast(&smb_dclocator.sdl_cv);
    }

out:
    (void) mutex_unlock(&smb_dclocator.sdl_mtx);
}

/*
 * If domain discovery is running, wait for it to finish.
 */
int
smb_ddiscover_wait(void)
{
    timestruc_t to;
    int rc = 0;

    (void) mutex_lock(&smb_dclocator.sdl_mtx);

    if (smb_dclocator.sdl_locate) {
        to.tv_sec = SMB_DCLOCATOR_TIMEOUT;
        to.tv_nsec = 0;
        rc = cond_reltimedwait(&smb_dclocator.sdl_cv,
            &smb_dclocator.sdl_mtx, &to);
    }

    (void) mutex_unlock(&smb_dclocator.sdl_mtx);

    return (rc);
}


/*
 * ==========================================================
 * DC discovery functions
 * ==========================================================
 */

/*
 * This is the domain and DC discovery service: it gets woken up whenever
 * there is need to locate a domain controller.
 *
 * Upon success, the SMB domain cache will be populated with the discovered
 * DC and domain info.
 */
/*ARGSUSED*/
static void *
smb_ddiscover_service(void *arg)
{
    smb_domainex_t dxi;
    smb_dclocator_t *sdl = arg;
    uint32_t status;
    boolean_t bad_dc;
    boolean_t cfg_chg;

    for (;;) {
        /*
         * Wait to be signaled for work by one of:
         * smb_locate_dc(), smb_ddiscover_refresh(),
         * smb_ddiscover_bad_dc()
         */
        syslog(LOG_DEBUG, "smb_ddiscover_service waiting");

        (void) mutex_lock(&sdl->sdl_mtx);
        while (!sdl->sdl_locate)
            (void) cond_wait(&sdl->sdl_cv,
                &sdl->sdl_mtx);

        if (!smb_config_getbool(SMB_CI_DOMAIN_MEMB)) {
            sdl->sdl_status = NT_STATUS_INVALID_SERVER_STATE;
            syslog(LOG_DEBUG, "smb_ddiscover_service: "
                "not a domain member");
            goto wait_again;
        }

        /*
         * Want to know if these change below.
         * Note: mutex held here
         */
    find_again:
        bad_dc = sdl->sdl_bad_dc;
        sdl->sdl_bad_dc = B_FALSE;
        if (bad_dc) {
            /*
             * Need to clear the current DC name or
             * ddiscover_bad_dc will keep setting bad_dc
             */
            sdl->sdl_dci.dc_name[0] = '\0';
        }
        cfg_chg = sdl->sdl_cfg_chg;
        sdl->sdl_cfg_chg = B_FALSE;

        (void) mutex_unlock(&sdl->sdl_mtx);

        syslog(LOG_DEBUG, "smb_ddiscover_service running "
            "cfg_chg=%d bad_dc=%d", (int)cfg_chg, (int)bad_dc);

        /*
         * Clear the cached DC now so that we'll ask idmap again.
         * If our current DC gave us errors, force rediscovery.
         */
        smb_ads_refresh(bad_dc);

        /*
         * Search for the DC, save the result.
         */
        bzero(&dxi, sizeof (dxi));
        status = smb_ddiscover_main(sdl->sdl_domain, &dxi);
        if (status == 0)
            smb_domain_save();
        (void) mutex_lock(&sdl->sdl_mtx);
        sdl->sdl_status = status;
        if (status == 0)
            sdl->sdl_dci = dxi.d_dci;

        /*
         * Run again if either of cfg_chg or bad_dc
         * was turned on during smb_ddiscover_main().
         * Note: mutex held here.
         */
        if (sdl->sdl_bad_dc) {
            syslog(LOG_DEBUG, "smb_ddiscover_service "
                "restart because bad_dc was set");
            goto find_again;
        }
        if (sdl->sdl_cfg_chg) {
            syslog(LOG_DEBUG, "smb_ddiscover_service "
                "restart because cfg_chg was set");
            goto find_again;
        }

    wait_again:
        sdl->sdl_locate = B_FALSE;
        sdl->sdl_bad_dc = B_FALSE;
        sdl->sdl_cfg_chg = B_FALSE;
        (void) cond_broadcast(&sdl->sdl_cv);
        (void) mutex_unlock(&sdl->sdl_mtx);
    }

    /*NOTREACHED*/
    return (NULL);
}

/*
 * Discovers a domain controller for the specified domain via DNS.
 * After the domain controller is discovered successfully primary and
 * trusted domain infromation will be queried using RPC queries.
 *
 * Caller should zero out *dxi before calling, and after a
 * successful return should call:  smb_domain_save()
 */
uint32_t
smb_ddiscover_main(char *domain, smb_domainex_t *dxi)
{
    uint32_t status;

    if (domain[0] == '\0') {
        syslog(LOG_DEBUG, "smb_ddiscover_main NULL domain");
        return (NT_STATUS_INTERNAL_ERROR);
    }

    if (smb_domain_start_update() != SMB_DOMAIN_SUCCESS) {
        syslog(LOG_DEBUG, "smb_ddiscover_main can't get lock");
        return (NT_STATUS_INTERNAL_ERROR);
    }

    status = smb_ads_lookup_msdcs(domain, &dxi->d_dci);
    if (status != 0) {
        syslog(LOG_DEBUG, "smb_ddiscover_main can't find DC (%s)",
            xlate_nt_status(status));
        goto out;
    }

    status = smb_ddiscover_qinfo(domain, dxi->d_dci.dc_name, dxi);
    if (status != 0) {
        syslog(LOG_DEBUG,
            "smb_ddiscover_main can't get domain info (%s)",
            xlate_nt_status(status));
        goto out;
    }

    smb_domain_update(dxi);

out:
    smb_domain_end_update();

    /* Don't need the trusted domain list anymore. */
    smb_domainex_free(dxi);

    return (status);
}

/*
 * Obtain primary and trusted domain information using LSA queries.
 *
 * domain - either NetBIOS or fully-qualified domain name
 */
static uint32_t
smb_ddiscover_qinfo(char *domain, char *server, smb_domainex_t *dxi)
{
    uint32_t ret, tmp;

    /* If we must return failure, use this first one. */
    ret = lsa_query_dns_domain_info(server, domain, &dxi->d_primary);
    if (ret == NT_STATUS_SUCCESS)
        goto success;
    tmp = smb_ddiscover_use_config(domain, dxi);
    if (tmp == NT_STATUS_SUCCESS)
        goto success;
    tmp = lsa_query_primary_domain_info(server, domain, &dxi->d_primary);
    if (tmp == NT_STATUS_SUCCESS)
        goto success;

    /* All of the above failed. */
    return (ret);

success:
    smb_ddiscover_enum_trusted(domain, server, dxi);
    return (NT_STATUS_SUCCESS);
}

/*
 * Obtain trusted domains information using LSA queries.
 *
 * domain - either NetBIOS or fully-qualified domain name.
 */
static void
smb_ddiscover_enum_trusted(char *domain, char *server, smb_domainex_t *dxi)
{
    smb_trusted_domains_t *list;
    uint32_t status;

    list = &dxi->d_trusted;
    status = lsa_enum_trusted_domains_ex(server, domain, list);
    if (status != NT_STATUS_SUCCESS)
        (void) lsa_enum_trusted_domains(server, domain, list);
}

/*
 * If the domain to be discovered matches the current domain (i.e the
 * value of either domain or fqdn configuration), then get the primary
 * domain information from SMF.
 */
static uint32_t
smb_ddiscover_use_config(char *domain, smb_domainex_t *dxi)
{
    boolean_t use;
    smb_domain_t *dinfo;

    dinfo = &dxi->d_primary;
    bzero(dinfo, sizeof (smb_domain_t));

    if (smb_config_get_secmode() != SMB_SECMODE_DOMAIN)
        return (NT_STATUS_UNSUCCESSFUL);

    smb_config_getdomaininfo(dinfo->di_nbname, dinfo->di_fqname,
        NULL, NULL, NULL);

    if (SMB_IS_FQDN(domain))
        use = (smb_strcasecmp(dinfo->di_fqname, domain, 0) == 0);
    else
        use = (smb_strcasecmp(dinfo->di_nbname, domain, 0) == 0);

    if (use)
        smb_config_getdomaininfo(NULL, NULL, dinfo->di_sid,
            dinfo->di_u.di_dns.ddi_forest,
            dinfo->di_u.di_dns.ddi_guid);

    return ((use) ? NT_STATUS_SUCCESS : NT_STATUS_UNSUCCESSFUL);
}

static void
smb_domainex_free(smb_domainex_t *dxi)
{
    free(dxi->d_trusted.td_domains);
    dxi->d_trusted.td_domains = NULL;
}

static void
smb_set_krb5_realm(char *domain)
{
    static char realm[MAXHOSTNAMELEN];

    if (domain == NULL || domain[0] == '\0') {
        (void) unsetenv("KRB5_DEFAULT_REALM");
        return;
    }

    /* In case krb5.conf is not configured, set the default realm. */
    (void) strlcpy(realm, domain, sizeof (realm));
    (void) smb_strupr(realm);

    (void) setenv("KRB5_DEFAULT_REALM", realm, 1);
}