libsmbns/common/smbns_ads.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) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
 */

#include <sys/param.h>
#include <ldap.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <netdb.h>
#include <pthread.h>
#include <unistd.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include <sys/synch.h>
#include <string.h>
#include <strings.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <assert.h>
#include <sasl/sasl.h>
#include <note.h>
#include <errno.h>
#include <cryptoutil.h>
#include <ads/dsgetdc.h>

#include <smbsrv/libsmbns.h>
#include <smbns_dyndns.h>
#include <smbns_krb.h>

#define SMB_ADS_AF_UNKNOWN(x)   (((x)->ipaddr.a_family != AF_INET) && \
    ((x)->ipaddr.a_family != AF_INET6))

#define SMB_ADS_MAXBUFLEN 100
#define SMB_ADS_DN_MAX  300
#define SMB_ADS_MAXMSGLEN 512
#define SMB_ADS_COMPUTERS_CN "Computers"
#define SMB_ADS_COMPUTER_NUM_ATTR 8
#define SMB_ADS_SHARE_NUM_ATTR 3
#define SMB_ADS_SITE_MAX MAXHOSTNAMELEN

#define SMB_ADS_MSDCS_SRV_DC_RR     "_ldap._tcp.dc._msdcs"
#define SMB_ADS_MSDCS_SRV_SITE_RR   "_ldap._tcp.%s._sites.dc._msdcs"

/*
 * domainControllerFunctionality
 *
 * This rootDSE attribute indicates the functional level of the DC.
 */
#define SMB_ADS_ATTR_DCLEVEL    "domainControllerFunctionality"
#define SMB_ADS_DCLEVEL_W2K 0
#define SMB_ADS_DCLEVEL_W2K3    2
#define SMB_ADS_DCLEVEL_W2K8    3
#define SMB_ADS_DCLEVEL_W2K8_R2 4

/*
 * msDs-supportedEncryptionTypes (Windows Server 2008 only)
 *
 * This attribute defines the encryption types supported by the system.
 * Encryption Types:
 *  - DES cbc mode with CRC-32
 *  - DES cbc mode with RSA-MD5
 *  - ArcFour with HMAC/md5
 *  - AES-128
 *  - AES-256
 */
#define SMB_ADS_ATTR_ENCTYPES   "msDs-supportedEncryptionTypes"
#define SMB_ADS_ENC_DES_CRC 1
#define SMB_ADS_ENC_DES_MD5 2
#define SMB_ADS_ENC_RC4     4
#define SMB_ADS_ENC_AES128  8
#define SMB_ADS_ENC_AES256  16

static krb5_enctype w2k8enctypes[] = {
    ENCTYPE_AES256_CTS_HMAC_SHA1_96,
    ENCTYPE_AES128_CTS_HMAC_SHA1_96,
    ENCTYPE_ARCFOUR_HMAC,
    ENCTYPE_DES_CBC_CRC,
    ENCTYPE_DES_CBC_MD5,
};

static krb5_enctype pre_w2k8enctypes[] = {
    ENCTYPE_ARCFOUR_HMAC,
    ENCTYPE_DES_CBC_CRC,
    ENCTYPE_DES_CBC_MD5,
};

#define SMB_ADS_ATTR_SAMACCT    "sAMAccountName"
#define SMB_ADS_ATTR_UPN    "userPrincipalName"
#define SMB_ADS_ATTR_SPN    "servicePrincipalName"
#define SMB_ADS_ATTR_CTL    "userAccountControl"
#define SMB_ADS_ATTR_DNSHOST    "dNSHostName"
#define SMB_ADS_ATTR_KVNO   "msDS-KeyVersionNumber"
#define SMB_ADS_ATTR_DN     "distinguishedName"

/*
 * UserAccountControl flags: manipulate user account properties.
 *
 * The hexadecimal value of the following property flags are based on MSDN
 * article # 305144.
 */
#define SMB_ADS_USER_ACCT_CTL_SCRIPT                0x00000001
#define SMB_ADS_USER_ACCT_CTL_ACCOUNTDISABLE            0x00000002
#define SMB_ADS_USER_ACCT_CTL_HOMEDIR_REQUIRED          0x00000008
#define SMB_ADS_USER_ACCT_CTL_LOCKOUT               0x00000010
#define SMB_ADS_USER_ACCT_CTL_PASSWD_NOTREQD            0x00000020
#define SMB_ADS_USER_ACCT_CTL_PASSWD_CANT_CHANGE        0x00000040
#define SMB_ADS_USER_ACCT_CTL_ENCRYPTED_TEXT_PWD_ALLOWED    0x00000080
#define SMB_ADS_USER_ACCT_CTL_TMP_DUP_ACCT          0x00000100
#define SMB_ADS_USER_ACCT_CTL_NORMAL_ACCT           0x00000200
#define SMB_ADS_USER_ACCT_CTL_INTERDOMAIN_TRUST_ACCT        0x00000800
#define SMB_ADS_USER_ACCT_CTL_WKSTATION_TRUST_ACCT      0x00001000
#define SMB_ADS_USER_ACCT_CTL_SRV_TRUST_ACCT            0x00002000
#define SMB_ADS_USER_ACCT_CTL_DONT_EXPIRE_PASSWD        0x00010000
#define SMB_ADS_USER_ACCT_CTL_MNS_LOGON_ACCT            0x00020000
#define SMB_ADS_USER_ACCT_CTL_SMARTCARD_REQUIRED        0x00040000
#define SMB_ADS_USER_ACCT_CTL_TRUSTED_FOR_DELEGATION        0x00080000
#define SMB_ADS_USER_ACCT_CTL_NOT_DELEGATED         0x00100000
#define SMB_ADS_USER_ACCT_CTL_USE_DES_KEY_ONLY          0x00200000
#define SMB_ADS_USER_ACCT_CTL_DONT_REQ_PREAUTH          0x00400000
#define SMB_ADS_USER_ACCT_CTL_PASSWD_EXPIRED            0x00800000
#define SMB_ADS_USER_ACCT_CTL_TRUSTED_TO_AUTH_FOR_DELEGATION    0x01000000

/*
 * Length of "dc=" prefix.
 */
#define SMB_ADS_DN_PREFIX_LEN   3

static char *smb_ads_computer_objcls[] = {
    "top", "person", "organizationalPerson",
    "user", "computer", NULL
};

static char *smb_ads_share_objcls[] = {
    "top", "leaf", "connectionPoint", "volume", NULL
};

/* Cached ADS server to communicate with */
static smb_ads_host_info_t *smb_ads_cached_host_info = NULL;
static mutex_t smb_ads_cached_host_mtx;

/*
 * SMB ADS config cache is maintained to facilitate the detection of
 * changes in configuration that is relevant to AD selection.
 */
typedef struct smb_ads_config {
    char c_site[SMB_ADS_SITE_MAX];
    mutex_t c_mtx;
} smb_ads_config_t;

static smb_ads_config_t smb_ads_cfg;


/* attribute/value pair */
typedef struct smb_ads_avpair {
    char *avp_attr;
    char *avp_val;
} smb_ads_avpair_t;

/* query status */
typedef enum smb_ads_qstat {
    SMB_ADS_STAT_ERR = -2,
    SMB_ADS_STAT_DUP,
    SMB_ADS_STAT_NOT_FOUND,
    SMB_ADS_STAT_FOUND
} smb_ads_qstat_t;

typedef struct smb_ads_host_list {
    int ah_cnt;
    smb_ads_host_info_t *ah_list;
} smb_ads_host_list_t;

static int smb_ads_open_main(smb_ads_handle_t **, char *, char *, char *);
static int smb_ads_add_computer(smb_ads_handle_t *, int, char *);
static int smb_ads_modify_computer(smb_ads_handle_t *, int, char *);
static int smb_ads_computer_op(smb_ads_handle_t *, int, int, char *);
static smb_ads_qstat_t smb_ads_lookup_computer_n_attr(smb_ads_handle_t *,
    smb_ads_avpair_t *, int, char *);
static int smb_ads_update_computer_cntrl_attr(smb_ads_handle_t *, int, char *);
static krb5_kvno smb_ads_lookup_computer_attr_kvno(smb_ads_handle_t *, char *);
static void smb_ads_free_cached_host(void);
static int smb_ads_alloc_attr(LDAPMod **, int);
static void smb_ads_free_attr(LDAPMod **);
static int smb_ads_get_dc_level(smb_ads_handle_t *);
static smb_ads_qstat_t smb_ads_find_computer(smb_ads_handle_t *, char *);
static smb_ads_qstat_t smb_ads_getattr(LDAP *, LDAPMessage *,
    smb_ads_avpair_t *);
static smb_ads_qstat_t smb_ads_get_qstat(smb_ads_handle_t *, LDAPMessage *,
    smb_ads_avpair_t *);
static boolean_t smb_ads_is_same_domain(char *, char *);
static smb_ads_host_info_t *smb_ads_dup_host_info(smb_ads_host_info_t *);
static char *smb_ads_get_sharedn(const char *, const char *, const char *);
static krb5_enctype *smb_ads_get_enctypes(int, int *);

/*
 * smb_ads_init
 *
 * Initializes the ADS config cache.
 */
void
smb_ads_init(void)
{
    (void) mutex_lock(&smb_ads_cfg.c_mtx);
    (void) smb_config_getstr(SMB_CI_ADS_SITE,
        smb_ads_cfg.c_site, SMB_ADS_SITE_MAX);
    (void) mutex_unlock(&smb_ads_cfg.c_mtx);

    /* Force -lads to load, for dtrace. */
    DsFreeDcInfo(NULL);
}

void
smb_ads_fini(void)
{
    smb_ads_free_cached_host();
}

/*
 * smb_ads_refresh
 *
 * This function will be called when smb/server SMF service is refreshed.
 * (See smbd_join.c)
 *
 * Clearing the smb_ads_cached_host_info would allow the next DC
 * discovery process to pick up an AD based on the new AD configuration.
 */
void
smb_ads_refresh(boolean_t force_rediscovery)
{
    char new_site[SMB_ADS_SITE_MAX];

    (void) smb_config_getstr(SMB_CI_ADS_SITE, new_site, SMB_ADS_SITE_MAX);
    (void) mutex_lock(&smb_ads_cfg.c_mtx);
    (void) strlcpy(smb_ads_cfg.c_site, new_site, SMB_ADS_SITE_MAX);
    (void) mutex_unlock(&smb_ads_cfg.c_mtx);

    smb_ads_free_cached_host();

    if (force_rediscovery) {
        (void) _DsForceRediscovery(NULL, 0);
    }
}


/*
 * smb_ads_build_unc_name
 *
 * Construct the UNC name of the share object in the format of
 * \\hostname.domain\shareUNC
 *
 * Returns 0 on success, -1 on error.
 */
int
smb_ads_build_unc_name(char *unc_name, int maxlen,
    const char *hostname, const char *shareUNC)
{
    char my_domain[MAXHOSTNAMELEN];

    if (smb_getfqdomainname(my_domain, sizeof (my_domain)) != 0)
        return (-1);

    (void) snprintf(unc_name, maxlen, "\\\\%s.%s\\%s",
        hostname, my_domain, shareUNC);
    return (0);
}

/*
 * The cached ADS host is no longer valid if one of the following criteria
 * is satisfied:
 *
 * 1) not in the specified domain
 * 2) not the sought host (if specified)
 * 3) not reachable
 *
 * The caller is responsible for acquiring the smb_ads_cached_host_mtx lock
 * prior to calling this function.
 *
 * Return B_TRUE if the cache host is still valid. Otherwise, return B_FALSE.
 */
static boolean_t
smb_ads_validate_cache_host(char *domain)
{
    if (!smb_ads_cached_host_info)
        return (B_FALSE);

    if (!smb_ads_is_same_domain(smb_ads_cached_host_info->name, domain))
        return (B_FALSE);

    return (B_TRUE);
}

/*
 * smb_ads_match_hosts_same_domain
 *
 * Returns true, if the cached ADS host is in the same domain as the
 * current (given) domain.
 */
static boolean_t
smb_ads_is_same_domain(char *cached_host_name, char *current_domain)
{
    char *cached_host_domain;

    if ((cached_host_name == NULL) || (current_domain == NULL))
        return (B_FALSE);

    cached_host_domain = strchr(cached_host_name, '.');
    if (cached_host_domain == NULL)
        return (B_FALSE);

    ++cached_host_domain;
    if (smb_strcasecmp(cached_host_domain, current_domain, 0))
        return (B_FALSE);

    return (B_TRUE);
}

/*
 * smb_ads_dup_host_info
 *
 * Duplicates the passed smb_ads_host_info_t structure.
 * Caller must free memory allocated by this method.
 *
 * Returns a reference to the duplicated smb_ads_host_info_t structure.
 * Returns NULL on error.
 */
static smb_ads_host_info_t *
smb_ads_dup_host_info(smb_ads_host_info_t *ads_host)
{
    smb_ads_host_info_t *dup_host;

    if (ads_host == NULL)
        return (NULL);

    dup_host = malloc(sizeof (smb_ads_host_info_t));

    if (dup_host != NULL)
        bcopy(ads_host, dup_host, sizeof (smb_ads_host_info_t));

    return (dup_host);
}

/*
 * smb_ads_find_host
 *
 * Finds an ADS host in a given domain.
 *
 * If the cached host is valid, it will be used. Otherwise, a DC will
 * be selected based on the following criteria:
 *
 * 1) pdc (aka preferred DC) configuration
 * 2) AD site configuration - the scope of the DNS lookup will be
 * restricted to the specified site.
 * 3) DC on the same subnet
 * 4) DC with the lowest priority/highest weight
 *
 * The above items are listed in decreasing preference order. The selected
 * DC must be online.
 *
 * If this function is called during domain join, the specified kpasswd server
 * takes precedence over preferred DC, AD site, and so on.
 *
 * Parameters:
 *   domain: fully-qualified domain name.
 *
 * Returns:
 *   A copy of the cached host info is returned. The caller is responsible
 *   for deallocating the memory returned by this function.
 */
/*ARGSUSED*/
smb_ads_host_info_t *
smb_ads_find_host(char *domain)
{
    smb_ads_host_info_t *host = NULL;
    DOMAIN_CONTROLLER_INFO *dci = NULL;
    struct sockaddr_storage *ss;
    uint32_t flags = DS_DS_FLAG;
    uint32_t status;
    int tries;

    (void) mutex_lock(&smb_ads_cached_host_mtx);
    if (smb_ads_validate_cache_host(domain)) {
        host = smb_ads_dup_host_info(smb_ads_cached_host_info);
        (void) mutex_unlock(&smb_ads_cached_host_mtx);
        return (host);
    }

    (void) mutex_unlock(&smb_ads_cached_host_mtx);
    smb_ads_free_cached_host();

    /*
     * The _real_ DC Locator is over in idmapd.
     * Door call over there to get it.
     */
    tries = 15;
again:
    status = _DsGetDcName(
        NULL,   /* ComputerName */
        domain,
        NULL,   /* DomainGuid */
        NULL,   /* SiteName */
        flags,
        &dci);
    switch (status) {
    case 0:
        break;
    /*
     * We can see these errors when joining a domain, if we race
     * asking idmap for the DC before it knows the new domain.
     */
    case NT_STATUS_NO_SUCH_DOMAIN:  /* Specified domain unknown */
    case NT_STATUS_INVALID_SERVER_STATE:    /*  not in domain mode. */
        if (--tries > 0) {
            (void) sleep(1);
            goto again;
        }
        /* FALLTHROUGH */
    case NT_STATUS_DOMAIN_CONTROLLER_NOT_FOUND:
    case NT_STATUS_CANT_WAIT:   /* timeout over in idmap */
    default:
        return (NULL);
    }

    host = calloc(1, sizeof (*host));
    if (host == NULL)
        goto out;

    (void) strlcpy(host->name, dci->DomainControllerName, MAXHOSTNAMELEN);
    ss = (void *)dci->_sockaddr;
    switch (ss->ss_family) {
    case AF_INET: {
        struct sockaddr_in *sin = (void *)ss;
        host->port = ntohs(sin->sin_port);
        host->ipaddr.a_family = AF_INET;
        (void) memcpy(&host->ipaddr.a_ipv4, &sin->sin_addr,
            sizeof (in_addr_t));
        break;
    }
    case AF_INET6: {
        struct sockaddr_in6 *sin6 = (void *)ss;
        host->port = ntohs(sin6->sin6_port);
        host->ipaddr.a_family = AF_INET6;
        (void) memcpy(&host->ipaddr.a_ipv6, &sin6->sin6_addr,
            sizeof (in6_addr_t));
        break;
    }
    default:
        syslog(LOG_ERR, "no addr for DC %s",
            dci->DomainControllerName);
        free(host);
        host = NULL;
        goto out;
    }

    (void) mutex_lock(&smb_ads_cached_host_mtx);
    if (!smb_ads_cached_host_info)
        smb_ads_cached_host_info = smb_ads_dup_host_info(host);
    host = smb_ads_dup_host_info(smb_ads_cached_host_info);
    (void) mutex_unlock(&smb_ads_cached_host_mtx);

out:
    DsFreeDcInfo(dci);
    return (host);
}

/*
 * Return the number of dots in a string.
 */
static int
smb_ads_count_dots(const char *s)
{
    int ndots = 0;

    while (*s) {
        if (*s++ == '.')
            ndots++;
    }

    return (ndots);
}

/*
 * Convert a domain name in dot notation to distinguished name format,
 * for example: sun.com -> dc=sun,dc=com.
 *
 * Returns a pointer to an allocated buffer containing the distinguished
 * name.
 */
static char *
smb_ads_convert_domain(const char *domain_name)
{
    const char *s;
    char *dn_name;
    char buf[2];
    int ndots;
    int len;

    if (domain_name == NULL || *domain_name == 0)
        return (NULL);

    ndots = smb_ads_count_dots(domain_name);
    ++ndots;
    len = strlen(domain_name) + (ndots * SMB_ADS_DN_PREFIX_LEN) + 1;

    if ((dn_name = malloc(len)) == NULL)
        return (NULL);

    bzero(dn_name, len);
    (void) strlcpy(dn_name, "dc=", len);

    buf[1] = '\0';
    s = domain_name;

    while (*s) {
        if (*s == '.') {
            (void) strlcat(dn_name, ",dc=", len);
        } else {
            buf[0] = *s;
            (void) strlcat(dn_name, buf, len);
        }
        ++s;
    }

    return (dn_name);
}

/*
 * smb_ads_free_cached_host
 *
 * Free the memory use by the global smb_ads_cached_host_info & set it to NULL.
 */
static void
smb_ads_free_cached_host(void)
{
    (void) mutex_lock(&smb_ads_cached_host_mtx);
    if (smb_ads_cached_host_info) {
        free(smb_ads_cached_host_info);
        smb_ads_cached_host_info = NULL;
    }
    (void) mutex_unlock(&smb_ads_cached_host_mtx);
}

/*
 * smb_ads_open
 * Open a LDAP connection to an ADS server if the system is in domain mode.
 * Acquire both Kerberos TGT and LDAP service tickets for the host principal.
 *
 * This function should only be called after the system is successfully joined
 * to a domain.
 */
smb_ads_handle_t *
smb_ads_open(void)
{
    char domain[MAXHOSTNAMELEN];
    smb_ads_handle_t *h;
    smb_ads_status_t err;

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

    if (smb_getfqdomainname(domain, MAXHOSTNAMELEN) != 0)
        return (NULL);

    err = smb_ads_open_main(&h, domain, NULL, NULL);
    if (err != 0) {
        smb_ads_log_errmsg(err);
        return (NULL);
    }

    return (h);
}

static int
smb_ads_saslcallback(LDAP *ld, unsigned flags, void *defaults, void *prompts)
{
    NOTE(ARGUNUSED(ld, defaults));
    sasl_interact_t *interact;

    if (prompts == NULL || flags != LDAP_SASL_INTERACTIVE)
        return (LDAP_PARAM_ERROR);

    /* There should be no extra arguemnts for SASL/GSSAPI authentication */
    for (interact = prompts; interact->id != SASL_CB_LIST_END;
        interact++) {
        interact->result = NULL;
        interact->len = 0;
    }
    return (LDAP_SUCCESS);
}

/*
 * smb_ads_open_main
 * Open a LDAP connection to an ADS server.
 * If ADS is enabled and the administrative username, password, and
 * ADS domain are defined then query DNS to find an ADS server if this is the
 * very first call to this routine.  After an ADS server is found then this
 * server will be used everytime this routine is called until the system is
 * rebooted or the ADS server becomes unavailable then an ADS server will
 * be queried again.  After the connection is made then an ADS handle
 * is created to be returned.
 *
 * After the LDAP connection, the LDAP version will be set to 3 using
 * ldap_set_option().
 *
 * The LDAP connection is bound before the ADS handle is returned.
 * Parameters:
 *   domain - fully-qualified domain name
 *   user   - the user account for whom the Kerberos TGT ticket and ADS
 *            service tickets are acquired.
 *   password - password of the specified user
 *
 * Returns:
 *   NULL              : can't connect to ADS server or other errors
 *   smb_ads_handle_t* : handle to ADS server
 */
static int
smb_ads_open_main(smb_ads_handle_t **hp, char *domain, char *user,
    char *password)
{
    smb_ads_handle_t *ah;
    LDAP *ld;
    int version = 3;
    smb_ads_host_info_t *ads_host = NULL;
    int err, rc;

    *hp = NULL;

    if (user != NULL) {
        err = smb_kinit(domain, user, password);
        if (err != 0)
            return (err);
        user = NULL;
        password = NULL;
    }

    ads_host = smb_ads_find_host(domain);
    if (ads_host == NULL)
        return (SMB_ADS_CANT_LOCATE_DC);

    ah = (smb_ads_handle_t *)malloc(sizeof (smb_ads_handle_t));
    if (ah == NULL) {
        free(ads_host);
        return (ENOMEM);
    }

    (void) memset(ah, 0, sizeof (smb_ads_handle_t));

    if ((ld = ldap_init(ads_host->name, ads_host->port)) == NULL) {
        syslog(LOG_ERR, "smbns: ldap_init failed");
        smb_ads_free_cached_host();
        free(ah);
        free(ads_host);
        return (SMB_ADS_LDAP_INIT);
    }

    if (ldap_set_option(ld, LDAP_OPT_PROTOCOL_VERSION, &version)
        != LDAP_SUCCESS) {
        smb_ads_free_cached_host();
        free(ah);
        free(ads_host);
        (void) ldap_unbind(ld);
        return (SMB_ADS_LDAP_SETOPT);
    }

    (void) ldap_set_option(ld, LDAP_OPT_REFERRALS, LDAP_OPT_OFF);
    ah->ld = ld;
    ah->domain = strdup(domain);

    if (ah->domain == NULL) {
        smb_ads_close(ah);
        free(ads_host);
        return (SMB_ADS_LDAP_SETOPT);
    }

    /*
     * ah->domain is often used for generating service principal name.
     * Convert it to lower case for RFC 4120 section 6.2.1 conformance.
     */
    (void) smb_strlwr(ah->domain);
    ah->domain_dn = smb_ads_convert_domain(domain);
    if (ah->domain_dn == NULL) {
        smb_ads_close(ah);
        free(ads_host);
        return (SMB_ADS_LDAP_SET_DOM);
    }

    ah->hostname = strdup(ads_host->name);
    if (ah->hostname == NULL) {
        smb_ads_close(ah);
        free(ads_host);
        return (ENOMEM);
    }
    (void) mutex_lock(&smb_ads_cfg.c_mtx);
    if (*smb_ads_cfg.c_site != '\0') {
        if ((ah->site = strdup(smb_ads_cfg.c_site)) == NULL) {
            smb_ads_close(ah);
            (void) mutex_unlock(&smb_ads_cfg.c_mtx);
            free(ads_host);
            return (ENOMEM);
        }
    } else {
        ah->site = NULL;
    }
    (void) mutex_unlock(&smb_ads_cfg.c_mtx);

    rc = ldap_sasl_interactive_bind_s(ah->ld, "", "GSSAPI", NULL, NULL,
        LDAP_SASL_INTERACTIVE, &smb_ads_saslcallback, NULL);
    if (rc != LDAP_SUCCESS) {
        syslog(LOG_ERR, "smbns: ldap_sasl_..._bind_s failed (%s)",
            ldap_err2string(rc));
        smb_ads_close(ah);
        free(ads_host);
        return (SMB_ADS_LDAP_SASL_BIND);
    }

    free(ads_host);
    *hp = ah;

    return (SMB_ADS_SUCCESS);
}

/*
 * smb_ads_close
 * Close connection to ADS server and free memory allocated for ADS handle.
 * LDAP unbind is called here.
 * Parameters:
 *   ah: handle to ADS server
 * Returns:
 *   void
 */
void
smb_ads_close(smb_ads_handle_t *ah)
{
    if (ah == NULL)
        return;
    /* close and free connection resources */
    if (ah->ld)
        (void) ldap_unbind(ah->ld);

    free(ah->domain);
    free(ah->domain_dn);
    free(ah->hostname);
    free(ah->site);
    free(ah);
}

/*
 * smb_ads_alloc_attr
 *
 * Since the attrs is a null-terminated array, all elements
 * in the array (except the last one) will point to allocated
 * memory.
 */
static int
smb_ads_alloc_attr(LDAPMod *attrs[], int num)
{
    int i;

    bzero(attrs, num * sizeof (LDAPMod *));
    for (i = 0; i < (num - 1); i++) {
        attrs[i] = (LDAPMod *)malloc(sizeof (LDAPMod));
        if (attrs[i] == NULL) {
            smb_ads_free_attr(attrs);
            return (-1);
        }
    }

    return (0);
}

/*
 * smb_ads_free_attr
 * Free memory allocated when publishing a share.
 * Parameters:
 *   attrs: an array of LDAPMod pointers
 * Returns:
 *   None
 */
static void
smb_ads_free_attr(LDAPMod *attrs[])
{
    int i;
    for (i = 0; attrs[i]; i++) {
        free(attrs[i]);
    }
}

/*
 * Returns share DN in an allocated buffer.  The format of the DN is
 * cn=<sharename>,<container RDNs>,<domain DN>
 *
 * If the domain DN is not included in the container parameter,
 * then it will be appended to create the share DN.
 *
 * The caller must free the allocated buffer.
 */
static char *
smb_ads_get_sharedn(const char *sharename, const char *container,
    const char *domain_dn)
{
    char *share_dn;
    int rc, offset, container_len, domain_len;
    boolean_t append_domain = B_TRUE;

    container_len = strlen(container);
    domain_len = strlen(domain_dn);

    if (container_len >= domain_len) {

        /* offset to last domain_len characters */
        offset = container_len - domain_len;

        if (smb_strcasecmp(container + offset,
            domain_dn, domain_len) == 0)
            append_domain = B_FALSE;
    }

    if (append_domain)
        rc = asprintf(&share_dn, "cn=%s,%s,%s", sharename,
            container, domain_dn);
    else
        rc = asprintf(&share_dn, "cn=%s,%s", sharename,
            container);

    return ((rc == -1) ? NULL : share_dn);
}

/*
 * smb_ads_add_share
 * Call by smb_ads_publish_share to create share object in ADS.
 * This routine specifies the attributes of an ADS LDAP share object. The first
 * attribute and values define the type of ADS object, the share object.  The
 * second attribute and value define the UNC of the share data for the share
 * object. The LDAP synchronous add command is used to add the object into ADS.
 * The container location to add the object needs to specified.
 * Parameters:
 *   ah          : handle to ADS server
 *   adsShareName: name of share object to be created in ADS
 *   shareUNC    : share name on NetForce
 *   adsContainer: location in ADS to create share object
 *
 * Returns:
 *   -1          : error
 *    0          : success
 */
int
smb_ads_add_share(smb_ads_handle_t *ah, const char *adsShareName,
    const char *unc_name, const char *adsContainer)
{
    LDAPMod *attrs[SMB_ADS_SHARE_NUM_ATTR];
    int j = 0;
    char *share_dn;
    int ret;
    char *unc_names[] = {(char *)unc_name, NULL};

    if ((share_dn = smb_ads_get_sharedn(adsShareName, adsContainer,
        ah->domain_dn)) == NULL)
        return (-1);

    if (smb_ads_alloc_attr(attrs, SMB_ADS_SHARE_NUM_ATTR) != 0) {
        free(share_dn);
        return (-1);
    }

    attrs[j]->mod_op = LDAP_MOD_ADD;
    attrs[j]->mod_type = "objectClass";
    attrs[j]->mod_values = smb_ads_share_objcls;

    attrs[++j]->mod_op = LDAP_MOD_ADD;
    attrs[j]->mod_type = "uNCName";
    attrs[j]->mod_values = unc_names;

    if ((ret = ldap_add_s(ah->ld, share_dn, attrs)) != LDAP_SUCCESS) {
        if (ret == LDAP_NO_SUCH_OBJECT) {
            syslog(LOG_ERR, "Failed to publish share %s in" \
                " AD.  Container does not exist: %s.\n",
                adsShareName, share_dn);

        } else {
            syslog(LOG_ERR, "Failed to publish share %s in" \
                " AD: %s (%s).\n", adsShareName, share_dn,
                ldap_err2string(ret));
        }
        smb_ads_free_attr(attrs);
        free(share_dn);
        return (ret);
    }
    free(share_dn);
    smb_ads_free_attr(attrs);

    return (0);
}

/*
 * smb_ads_del_share
 * Call by smb_ads_remove_share to remove share object from ADS.  The container
 * location to remove the object needs to specified.  The LDAP synchronous
 * delete command is used.
 * Parameters:
 *   ah          : handle to ADS server
 *   adsShareName: name of share object in ADS to be removed
 *   adsContainer: location of share object in ADS
 * Returns:
 *   -1          : error
 *    0          : success
 */
static int
smb_ads_del_share(smb_ads_handle_t *ah, const char *adsShareName,
    const char *adsContainer)
{
    char *share_dn;
    int ret;

    if ((share_dn = smb_ads_get_sharedn(adsShareName, adsContainer,
        ah->domain_dn)) == NULL)
        return (-1);

    if ((ret = ldap_delete_s(ah->ld, share_dn)) != LDAP_SUCCESS) {
        smb_tracef("ldap_delete: %s", ldap_err2string(ret));
        free(share_dn);
        return (-1);
    }
    free(share_dn);

    return (0);
}


/*
 * smb_ads_escape_search_filter_chars
 *
 * This routine will escape the special characters found in a string
 * that will later be passed to the ldap search filter.
 *
 * RFC 1960 - A String Representation of LDAP Search Filters
 * 3.  String Search Filter Definition
 * If a value must contain one of the characters '*' OR '(' OR ')',
 * these characters
 * should be escaped by preceding them with the backslash '\' character.
 *
 * RFC 2252 - LDAP Attribute Syntax Definitions
 * a backslash quoting mechanism is used to escape
 * the following separator symbol character (such as "'", "$" or "#") if
 * it should occur in that string.
 */
static int
smb_ads_escape_search_filter_chars(const char *src, char *dst)
{
    int avail = SMB_ADS_MAXBUFLEN - 1; /* reserve a space for NULL char */

    if (src == NULL || dst == NULL)
        return (-1);

    while (*src) {
        if (!avail) {
            *dst = 0;
            return (-1);
        }

        switch (*src) {
        case '\\':
        case '\'':
        case '$':
        case '#':
        case '*':
        case '(':
        case ')':
            *dst++ = '\\';
            avail--;
            /* fall through */

        default:
            *dst++ = *src++;
            avail--;
        }
    }

    *dst = 0;

    return (0);
}

/*
 * smb_ads_lookup_share
 * The search filter is set to search for a specific share name in the
 * specified ADS container.  The LDSAP synchronous search command is used.
 * Parameters:
 *   ah          : handle to ADS server
 *   adsShareName: name of share object in ADS to be searched
 *   adsContainer: location of share object in ADS
 * Returns:
 *   -1          : error
 *    0          : not found
 *    1          : found
 */
int
smb_ads_lookup_share(smb_ads_handle_t *ah, const char *adsShareName,
    const char *adsContainer, char *unc_name)
{
    char *attrs[4], filter[SMB_ADS_MAXBUFLEN];
    char *share_dn;
    int ret;
    LDAPMessage *res;
    char tmpbuf[SMB_ADS_MAXBUFLEN];

    if (adsShareName == NULL || adsContainer == NULL)
        return (-1);

    if ((share_dn = smb_ads_get_sharedn(adsShareName, adsContainer,
        ah->domain_dn)) == NULL)
        return (-1);

    res = NULL;
    attrs[0] = "cn";
    attrs[1] = "objectClass";
    attrs[2] = "uNCName";
    attrs[3] = NULL;

    if (smb_ads_escape_search_filter_chars(unc_name, tmpbuf) != 0) {
        free(share_dn);
        return (-1);
    }

    (void) snprintf(filter, sizeof (filter),
        "(&(objectClass=volume)(uNCName=%s))", tmpbuf);

    if ((ret = ldap_search_s(ah->ld, share_dn,
        LDAP_SCOPE_BASE, filter, attrs, 0, &res)) != LDAP_SUCCESS) {
        if (ret != LDAP_NO_SUCH_OBJECT)
            smb_tracef("%s: ldap_search: %s", share_dn,
                ldap_err2string(ret));

        (void) ldap_msgfree(res);
        free(share_dn);
        return (0);
    }

    (void) free(share_dn);

    /* no match is found */
    if (ldap_count_entries(ah->ld, res) == 0) {
        (void) ldap_msgfree(res);
        return (0);
    }

    /* free the search results */
    (void) ldap_msgfree(res);

    return (1);
}

/*
 * smb_ads_publish_share
 * Publish share into ADS.  If a share name already exist in ADS in the same
 * container then the existing share object is removed before adding the new
 * share object.
 * Parameters:
 *   ah          : handle return from smb_ads_open
 *   adsShareName: name of share to be added to ADS directory
 *   shareUNC    : name of share on client, can be NULL to use the same name
 *                 as adsShareName
 *   adsContainer: location for share to be added in ADS directory, ie
 *                   ou=share_folder
 *   uncType     : use UNC_HOSTNAME to use hostname for UNC, use UNC_HOSTADDR
 *                   to use host ip addr for UNC.
 * Returns:
 *   -1          : error
 *    0          : success
 */
int
smb_ads_publish_share(smb_ads_handle_t *ah, const char *adsShareName,
    const char *shareUNC, const char *adsContainer, const char *hostname)
{
    int ret;
    char unc_name[SMB_ADS_MAXBUFLEN];

    if (adsShareName == NULL || adsContainer == NULL)
        return (-1);

    if (shareUNC == 0 || *shareUNC == 0)
        shareUNC = adsShareName;

    if (smb_ads_build_unc_name(unc_name, sizeof (unc_name),
        hostname, shareUNC) < 0)
        return (-1);

    ret = smb_ads_lookup_share(ah, adsShareName, adsContainer, unc_name);

    switch (ret) {
    case 1:
        (void) smb_ads_del_share(ah, adsShareName, adsContainer);
        ret = smb_ads_add_share(ah, adsShareName, unc_name,
            adsContainer);
        break;

    case 0:
        ret = smb_ads_add_share(ah, adsShareName, unc_name,
            adsContainer);
        if (ret == LDAP_ALREADY_EXISTS)
            ret = -1;

        break;

    case -1:
    default:
        /* return with error code */
        ret = -1;
    }

    return (ret);
}

/*
 * smb_ads_remove_share
 * Remove share from ADS.  A search is done first before explicitly removing
 * the share.
 * Parameters:
 *   ah          : handle return from smb_ads_open
 *   adsShareName: name of share to be removed from ADS directory
 *   adsContainer: location for share to be removed from ADS directory, ie
 *                   ou=share_folder
 * Returns:
 *   -1          : error
 *    0          : success
 */
int
smb_ads_remove_share(smb_ads_handle_t *ah, const char *adsShareName,
    const char *shareUNC, const char *adsContainer, const char *hostname)
{
    int ret;
    char unc_name[SMB_ADS_MAXBUFLEN];

    if (adsShareName == NULL || adsContainer == NULL)
        return (-1);
    if (shareUNC == 0 || *shareUNC == 0)
        shareUNC = adsShareName;

    if (smb_ads_build_unc_name(unc_name, sizeof (unc_name),
        hostname, shareUNC) < 0)
        return (-1);

    ret = smb_ads_lookup_share(ah, adsShareName, adsContainer, unc_name);
    if (ret == 0)
        return (0);
    if (ret == -1)
        return (-1);

    return (smb_ads_del_share(ah, adsShareName, adsContainer));
}

/*
 * smb_ads_get_default_comp_container_dn
 *
 * Build the distinguished name for the default computer conatiner (i.e. the
 * pre-defined Computers container).
 */
static void
smb_ads_get_default_comp_container_dn(smb_ads_handle_t *ah, char *buf,
    size_t buflen)
{
    (void) snprintf(buf, buflen, "cn=%s,%s", SMB_ADS_COMPUTERS_CN,
        ah->domain_dn);
}

/*
 * smb_ads_get_default_comp_dn
 *
 * Build the distinguished name for this system.
 */
static void
smb_ads_get_default_comp_dn(smb_ads_handle_t *ah, char *buf, size_t buflen)
{
    char nbname[NETBIOS_NAME_SZ];
    char container_dn[SMB_ADS_DN_MAX];

    (void) smb_getnetbiosname(nbname, sizeof (nbname));
    smb_ads_get_default_comp_container_dn(ah, container_dn, SMB_ADS_DN_MAX);
    (void) snprintf(buf, buflen, "cn=%s,%s", nbname, container_dn);
}

/*
 * smb_ads_add_computer
 *
 * Returns 0 upon success. Otherwise, returns -1.
 */
static int
smb_ads_add_computer(smb_ads_handle_t *ah, int dclevel, char *dn)
{
    return (smb_ads_computer_op(ah, LDAP_MOD_ADD, dclevel, dn));
}

/*
 * smb_ads_modify_computer
 *
 * Returns 0 upon success. Otherwise, returns -1.
 */
static int
smb_ads_modify_computer(smb_ads_handle_t *ah, int dclevel, char *dn)
{
    return (smb_ads_computer_op(ah, LDAP_MOD_REPLACE, dclevel, dn));
}

/*
 * smb_ads_get_dc_level
 *
 * Returns the functional level of the DC upon success.
 * Otherwise, -1 is returned.
 */
static int
smb_ads_get_dc_level(smb_ads_handle_t *ah)
{
    LDAPMessage *res, *entry;
    char *attr[2];
    char **vals;
    int rc = -1;

    res = NULL;
    attr[0] = SMB_ADS_ATTR_DCLEVEL;
    attr[1] = NULL;
    if (ldap_search_s(ah->ld, "", LDAP_SCOPE_BASE, NULL, attr,
        0, &res) != LDAP_SUCCESS) {
        (void) ldap_msgfree(res);
        return (-1);
    }

    /* no match for the specified attribute is found */
    if (ldap_count_entries(ah->ld, res) == 0) {
        (void) ldap_msgfree(res);
        return (-1);
    }

    entry = ldap_first_entry(ah->ld, res);
    if (entry) {
        if ((vals = ldap_get_values(ah->ld, entry,
            SMB_ADS_ATTR_DCLEVEL)) == NULL) {
            /*
             * Observed the values aren't populated
             * by the Windows 2000 server.
             */
            (void) ldap_msgfree(res);
            return (SMB_ADS_DCLEVEL_W2K);
        }

        if (vals[0] != NULL)
            rc = atoi(vals[0]);

        ldap_value_free(vals);
    }

    (void) ldap_msgfree(res);
    return (rc);
}

/*
 * The fully-qualified hostname returned by this function is often used for
 * constructing service principal name.  Return the fully-qualified hostname
 * in lower case for RFC 4120 section 6.2.1 conformance.
 */
static int
smb_ads_getfqhostname(smb_ads_handle_t *ah, char *fqhost, int len)
{
    if (smb_gethostname(fqhost, len, SMB_CASE_LOWER) != 0)
        return (-1);

    (void) snprintf(fqhost, len, "%s.%s", fqhost,
        ah->domain);

    return (0);
}

static int
smb_ads_computer_op(smb_ads_handle_t *ah, int op, int dclevel, char *dn)
{
    LDAPMod *attrs[SMB_ADS_COMPUTER_NUM_ATTR];
    char *sam_val[2];
    char *ctl_val[2], *fqh_val[2];
    char *encrypt_val[2];
    int j = -1;
    int ret, usrctl_flags = 0;
    char sam_acct[SMB_SAMACCT_MAXLEN];
    char fqhost[MAXHOSTNAMELEN];
    char usrctl_buf[16];
    char encrypt_buf[16];
    int max;
    smb_krb5_pn_set_t spn, upn;

    if (smb_getsamaccount(sam_acct, sizeof (sam_acct)) != 0)
        return (-1);

    if (smb_ads_getfqhostname(ah, fqhost, MAXHOSTNAMELEN))
        return (-1);

    /* The SPN attribute is multi-valued and must be 1 or greater */
    if (smb_krb5_get_pn_set(&spn, SMB_PN_SPN_ATTR, ah->domain) == 0)
        return (-1);

    /* The UPN attribute is single-valued and cannot be zero */
    if (smb_krb5_get_pn_set(&upn, SMB_PN_UPN_ATTR, ah->domain) != 1) {
        smb_krb5_free_pn_set(&spn);
        smb_krb5_free_pn_set(&upn);
        return (-1);
    }

    max = (SMB_ADS_COMPUTER_NUM_ATTR - ((op != LDAP_MOD_ADD) ? 1 : 0))
        - (dclevel >= SMB_ADS_DCLEVEL_W2K8 ?  0 : 1);

    if (smb_ads_alloc_attr(attrs, max) != 0) {
        smb_krb5_free_pn_set(&spn);
        smb_krb5_free_pn_set(&upn);
        return (-1);
    }

    /* objectClass attribute is not modifiable. */
    if (op == LDAP_MOD_ADD) {
        attrs[++j]->mod_op = op;
        attrs[j]->mod_type = "objectClass";
        attrs[j]->mod_values = smb_ads_computer_objcls;
    }

    attrs[++j]->mod_op = op;
    attrs[j]->mod_type = SMB_ADS_ATTR_SAMACCT;
    sam_val[0] = sam_acct;
    sam_val[1] = 0;
    attrs[j]->mod_values = sam_val;

    attrs[++j]->mod_op = op;
    attrs[j]->mod_type = SMB_ADS_ATTR_UPN;
    attrs[j]->mod_values = upn.s_pns;

    attrs[++j]->mod_op = op;
    attrs[j]->mod_type = SMB_ADS_ATTR_SPN;
    attrs[j]->mod_values =  spn.s_pns;

    attrs[++j]->mod_op = op;
    attrs[j]->mod_type = SMB_ADS_ATTR_CTL;
    usrctl_flags |= (SMB_ADS_USER_ACCT_CTL_WKSTATION_TRUST_ACCT |
        SMB_ADS_USER_ACCT_CTL_PASSWD_NOTREQD |
        SMB_ADS_USER_ACCT_CTL_ACCOUNTDISABLE);
    (void) snprintf(usrctl_buf, sizeof (usrctl_buf), "%d", usrctl_flags);
    ctl_val[0] = usrctl_buf;
    ctl_val[1] = 0;
    attrs[j]->mod_values = ctl_val;

    attrs[++j]->mod_op = op;
    attrs[j]->mod_type = SMB_ADS_ATTR_DNSHOST;
    fqh_val[0] = fqhost;
    fqh_val[1] = 0;
    attrs[j]->mod_values = fqh_val;

    /* enctypes support starting in Windows Server 2008 */
    if (dclevel > SMB_ADS_DCLEVEL_W2K3) {
        attrs[++j]->mod_op = op;
        attrs[j]->mod_type = SMB_ADS_ATTR_ENCTYPES;
        (void) snprintf(encrypt_buf, sizeof (encrypt_buf), "%d",
            SMB_ADS_ENC_AES256 + SMB_ADS_ENC_AES128 + SMB_ADS_ENC_RC4 +
            SMB_ADS_ENC_DES_MD5 + SMB_ADS_ENC_DES_CRC);
        encrypt_val[0] = encrypt_buf;
        encrypt_val[1] = 0;
        attrs[j]->mod_values = encrypt_val;
    }

    switch (op) {
    case LDAP_MOD_ADD:
        if ((ret = ldap_add_s(ah->ld, dn, attrs)) != LDAP_SUCCESS) {
            syslog(LOG_NOTICE, "ldap_add: %s",
                ldap_err2string(ret));
            ret = -1;
        }
        break;

    case LDAP_MOD_REPLACE:
        if ((ret = ldap_modify_s(ah->ld, dn, attrs)) != LDAP_SUCCESS) {
            syslog(LOG_NOTICE, "ldap_modify: %s",
                ldap_err2string(ret));
            ret = -1;
        }
        break;

    default:
        ret = -1;

    }

    smb_ads_free_attr(attrs);
    smb_krb5_free_pn_set(&spn);
    smb_krb5_free_pn_set(&upn);

    return (ret);
}

/*
 * Delete an ADS computer account.
 */
static void
smb_ads_del_computer(smb_ads_handle_t *ah, char *dn)
{
    int rc;

    if ((rc = ldap_delete_s(ah->ld, dn)) != LDAP_SUCCESS)
        smb_tracef("ldap_delete: %s", ldap_err2string(rc));
}

/*
 * Gets the value of the given attribute.
 */
static smb_ads_qstat_t
smb_ads_getattr(LDAP *ld, LDAPMessage *entry, smb_ads_avpair_t *avpair)
{
    char **vals;
    smb_ads_qstat_t rc = SMB_ADS_STAT_FOUND;

    assert(avpair);
    avpair->avp_val = NULL;
    vals = ldap_get_values(ld, entry, avpair->avp_attr);
    if (!vals)
        return (SMB_ADS_STAT_NOT_FOUND);

    if (!vals[0]) {
        ldap_value_free(vals);
        return (SMB_ADS_STAT_NOT_FOUND);
    }

    avpair->avp_val = strdup(vals[0]);
    if (!avpair->avp_val)
        rc = SMB_ADS_STAT_ERR;

    ldap_value_free(vals);
    return (rc);
}

/*
 * Process query's result.
 */
static smb_ads_qstat_t
smb_ads_get_qstat(smb_ads_handle_t *ah, LDAPMessage *res,
    smb_ads_avpair_t *avpair)
{
    char fqhost[MAXHOSTNAMELEN];
    smb_ads_avpair_t dnshost_avp;
    smb_ads_qstat_t rc = SMB_ADS_STAT_FOUND;
    LDAPMessage *entry;

    if (smb_ads_getfqhostname(ah, fqhost, MAXHOSTNAMELEN))
        return (SMB_ADS_STAT_ERR);

    if (ldap_count_entries(ah->ld, res) == 0)
        return (SMB_ADS_STAT_NOT_FOUND);

    if ((entry = ldap_first_entry(ah->ld, res)) == NULL)
        return (SMB_ADS_STAT_ERR);

    dnshost_avp.avp_attr = SMB_ADS_ATTR_DNSHOST;
    rc = smb_ads_getattr(ah->ld, entry, &dnshost_avp);

    switch (rc) {
    case SMB_ADS_STAT_FOUND:
        /*
         * Returns SMB_ADS_STAT_DUP to avoid overwriting
         * the computer account of another system whose
         * NetBIOS name collides with that of the current
         * system.
         */
        if (strcasecmp(dnshost_avp.avp_val, fqhost))
            rc = SMB_ADS_STAT_DUP;

        free(dnshost_avp.avp_val);
        break;

    case SMB_ADS_STAT_NOT_FOUND:
        /*
         * Pre-created computer account doesn't have
         * the dNSHostname attribute. It's been observed
         * that the dNSHostname attribute is only set after
         * a successful domain join.
         * Returns SMB_ADS_STAT_FOUND as the account is
         * pre-created for the current system.
         */
        rc = SMB_ADS_STAT_FOUND;
        break;

    default:
        break;
    }

    if (rc != SMB_ADS_STAT_FOUND)
        return (rc);

    if (avpair)
        rc = smb_ads_getattr(ah->ld, entry, avpair);

    return (rc);

}

/*
 * smb_ads_lookup_computer_n_attr
 *
 * If avpair is NULL, checks the status of the specified computer account.
 * Otherwise, looks up the value of the specified computer account's attribute.
 * If found, the value field of the avpair will be allocated and set. The
 * caller should free the allocated buffer.
 *
 * Return:
 *  SMB_ADS_STAT_FOUND  - if both the computer and the specified attribute is
 *                        found.
 *  SMB_ADS_STAT_NOT_FOUND - if either the computer or the specified attribute
 *                           is not found.
 *  SMB_ADS_STAT_DUP - if the computer account is already used by other systems
 *                     in the AD. This could happen if the hostname of multiple
 *                     systems resolved to the same NetBIOS name.
 *  SMB_ADS_STAT_ERR - any failure.
 */
static smb_ads_qstat_t
smb_ads_lookup_computer_n_attr(smb_ads_handle_t *ah, smb_ads_avpair_t *avpair,
    int scope, char *dn)
{
    char *attrs[3], filter[SMB_ADS_MAXBUFLEN];
    LDAPMessage *res;
    char sam_acct[SMB_SAMACCT_MAXLEN], sam_acct2[SMB_SAMACCT_MAXLEN];
    smb_ads_qstat_t rc;

    if (smb_getsamaccount(sam_acct, sizeof (sam_acct)) != 0)
        return (SMB_ADS_STAT_ERR);

    res = NULL;
    attrs[0] = SMB_ADS_ATTR_DNSHOST;
    attrs[1] = NULL;
    attrs[2] = NULL;

    if (avpair) {
        if (!avpair->avp_attr)
            return (SMB_ADS_STAT_ERR);

        attrs[1] = avpair->avp_attr;
    }

    if (smb_ads_escape_search_filter_chars(sam_acct, sam_acct2) != 0)
        return (SMB_ADS_STAT_ERR);

    (void) snprintf(filter, sizeof (filter),
        "(&(objectClass=computer)(%s=%s))", SMB_ADS_ATTR_SAMACCT,
        sam_acct2);

    if (ldap_search_s(ah->ld, dn, scope, filter, attrs, 0,
        &res) != LDAP_SUCCESS) {
        (void) ldap_msgfree(res);
        return (SMB_ADS_STAT_NOT_FOUND);
    }

    rc = smb_ads_get_qstat(ah, res, avpair);
    /* free the search results */
    (void) ldap_msgfree(res);
    return (rc);
}

/*
 * smb_ads_find_computer
 *
 * Starts by searching for the system's AD computer object in the default
 * container (i.e. cn=Computers).  If not found, searches the entire directory.
 * If found, 'dn' will be set to the distinguished name of the system's AD
 * computer object.
 */
static smb_ads_qstat_t
smb_ads_find_computer(smb_ads_handle_t *ah, char *dn)
{
    smb_ads_qstat_t stat;
    smb_ads_avpair_t avpair;

    avpair.avp_attr = SMB_ADS_ATTR_DN;
    smb_ads_get_default_comp_container_dn(ah, dn, SMB_ADS_DN_MAX);
    stat = smb_ads_lookup_computer_n_attr(ah, &avpair, LDAP_SCOPE_ONELEVEL,
        dn);

    if (stat == SMB_ADS_STAT_NOT_FOUND) {
        (void) strlcpy(dn, ah->domain_dn, SMB_ADS_DN_MAX);
        stat = smb_ads_lookup_computer_n_attr(ah, &avpair,
            LDAP_SCOPE_SUBTREE, dn);
    }

    if (stat == SMB_ADS_STAT_FOUND) {
        (void) strlcpy(dn, avpair.avp_val, SMB_ADS_DN_MAX);
        free(avpair.avp_val);
    }

    return (stat);
}

/*
 * smb_ads_update_computer_cntrl_attr
 *
 * Modify the user account control attribute of an existing computer
 * object on AD.
 *
 * Returns LDAP error code.
 */
static int
smb_ads_update_computer_cntrl_attr(smb_ads_handle_t *ah, int flags, char *dn)
{
    LDAPMod *attrs[2];
    char *ctl_val[2];
    int ret = 0;
    char usrctl_buf[16];

    if (smb_ads_alloc_attr(attrs, sizeof (attrs) / sizeof (LDAPMod *)) != 0)
        return (LDAP_NO_MEMORY);

    attrs[0]->mod_op = LDAP_MOD_REPLACE;
    attrs[0]->mod_type = SMB_ADS_ATTR_CTL;

    (void) snprintf(usrctl_buf, sizeof (usrctl_buf), "%d", flags);
    ctl_val[0] = usrctl_buf;
    ctl_val[1] = 0;
    attrs[0]->mod_values = ctl_val;
    if ((ret = ldap_modify_s(ah->ld, dn, attrs)) != LDAP_SUCCESS) {
        syslog(LOG_NOTICE, "ldap_modify: %s", ldap_err2string(ret));
    }

    smb_ads_free_attr(attrs);
    return (ret);
}

/*
 * smb_ads_lookup_computer_attr_kvno
 *
 * Lookup the value of the Kerberos version number attribute of the computer
 * account.
 */
static krb5_kvno
smb_ads_lookup_computer_attr_kvno(smb_ads_handle_t *ah, char *dn)
{
    smb_ads_avpair_t avpair;
    int kvno = 1;

    avpair.avp_attr = SMB_ADS_ATTR_KVNO;
    if (smb_ads_lookup_computer_n_attr(ah, &avpair,
        LDAP_SCOPE_BASE, dn) == SMB_ADS_STAT_FOUND) {
        kvno = atoi(avpair.avp_val);
        free(avpair.avp_val);
    }

    return (kvno);
}

/*
 * smb_ads_join
 *
 * Besides the NT-4 style domain join (using MS-RPC), CIFS server also
 * provides the domain join using Kerberos Authentication, Keberos
 * Change & Set password, and LDAP protocols. Basically, AD join
 * operation would require the following tickets to be acquired for the
 * the user account that is provided for the domain join.
 *
 * 1) a Keberos TGT ticket,
 * 2) a ldap service ticket, and
 * 3) kadmin/changpw service ticket
 *
 * The ADS client first sends a ldap search request to find out whether
 * or not the workstation trust account already exists in the Active Directory.
 * The existing computer object for this workstation will be removed and
 * a new one will be added. The machine account password is randomly
 * generated and set for the newly created computer object using KPASSWD
 * protocol (See RFC 3244). Once the password is set, our ADS client
 * finalizes the machine account by modifying the user acount control
 * attribute of the computer object. Kerberos keys derived from the machine
 * account password will be stored locally in /etc/krb5/krb5.keytab file.
 * That would be needed while acquiring Kerberos TGT ticket for the host
 * principal after the domain join operation.
 */
smb_ads_status_t
smb_ads_join(char *domain, char *user, char *usr_passwd, char *machine_passwd)
{
    smb_ads_handle_t *ah = NULL;
    krb5_context ctx = NULL;
    krb5_principal *krb5princs = NULL;
    krb5_kvno kvno;
    boolean_t delete = B_TRUE;
    smb_ads_status_t rc;
    boolean_t new_acct;
    int dclevel, num, usrctl_flags = 0;
    smb_ads_qstat_t qstat;
    char dn[SMB_ADS_DN_MAX];
    char tmpfile[] = SMBNS_KRB5_KEYTAB_TMP;
    int cnt, x;
    smb_krb5_pn_set_t spns;
    krb5_enctype *encptr;

    rc = smb_ads_open_main(&ah, domain, user, usr_passwd);
    if (rc != 0) {
        smb_ccache_remove(SMB_CCACHE_PATH);
        return (rc);
    }

    if ((dclevel = smb_ads_get_dc_level(ah)) == -1) {
        smb_ads_close(ah);
        smb_ccache_remove(SMB_CCACHE_PATH);
        return (SMB_ADJOIN_ERR_GET_DCLEVEL);
    }

    qstat = smb_ads_find_computer(ah, dn);
    switch (qstat) {
    case SMB_ADS_STAT_FOUND:
        new_acct = B_FALSE;
        if (smb_ads_modify_computer(ah, dclevel, dn) != 0) {
            smb_ads_close(ah);
            smb_ccache_remove(SMB_CCACHE_PATH);
            return (SMB_ADJOIN_ERR_MOD_TRUST_ACCT);
        }
        break;

    case SMB_ADS_STAT_NOT_FOUND:
        new_acct = B_TRUE;
        smb_ads_get_default_comp_dn(ah, dn, SMB_ADS_DN_MAX);
        if (smb_ads_add_computer(ah, dclevel, dn) != 0) {
            smb_ads_close(ah);
            smb_ccache_remove(SMB_CCACHE_PATH);
            return (SMB_ADJOIN_ERR_ADD_TRUST_ACCT);
        }
        break;

    default:
        if (qstat == SMB_ADS_STAT_DUP)
            rc = SMB_ADJOIN_ERR_DUP_TRUST_ACCT;
        else
            rc = SMB_ADJOIN_ERR_TRUST_ACCT;
        smb_ads_close(ah);
        smb_ccache_remove(SMB_CCACHE_PATH);
        return (rc);
    }

    if (smb_krb5_ctx_init(&ctx) != 0) {
        rc = SMB_ADJOIN_ERR_INIT_KRB_CTX;
        goto adjoin_cleanup;
    }

    if (smb_krb5_get_pn_set(&spns, SMB_PN_KEYTAB_ENTRY, ah->domain) == 0) {
        rc = SMB_ADJOIN_ERR_GET_SPNS;
        goto adjoin_cleanup;
    }

    if (smb_krb5_get_kprincs(ctx, spns.s_pns, spns.s_cnt, &krb5princs)
        != 0) {
        smb_krb5_free_pn_set(&spns);
        rc = SMB_ADJOIN_ERR_GET_SPNS;
        goto adjoin_cleanup;
    }

    cnt = spns.s_cnt;
    smb_krb5_free_pn_set(&spns);

    /* New machine_passwd was filled in by our caller. */
    if (smb_krb5_setpwd(ctx, ah->domain, machine_passwd) != 0) {
        rc = SMB_ADJOIN_ERR_KSETPWD;
        goto adjoin_cleanup;
    }

    kvno = smb_ads_lookup_computer_attr_kvno(ah, dn);

    /*
     * Only members of Domain Admins and Enterprise Admins can set
     * the TRUSTED_FOR_DELEGATION userAccountControl flag.
     * Try to set this, but don't fail the join if we can't.
     * Look into just removing this...
     */
    usrctl_flags = (
        SMB_ADS_USER_ACCT_CTL_WKSTATION_TRUST_ACCT |
        SMB_ADS_USER_ACCT_CTL_TRUSTED_FOR_DELEGATION |
        SMB_ADS_USER_ACCT_CTL_DONT_EXPIRE_PASSWD);
set_ctl_again:
    x = smb_ads_update_computer_cntrl_attr(ah, usrctl_flags, dn);
    if (x != LDAP_SUCCESS && (usrctl_flags &
        SMB_ADS_USER_ACCT_CTL_TRUSTED_FOR_DELEGATION) != 0) {
        syslog(LOG_NOTICE, "Unable to set the "
"TRUSTED_FOR_DELEGATION userAccountControl flag on the "
"machine account in Active Directory.  It may be necessary "
"to set that via Active Directory administration.");
        usrctl_flags &=
            ~SMB_ADS_USER_ACCT_CTL_TRUSTED_FOR_DELEGATION;
        goto set_ctl_again;
    }
    if (x != LDAP_SUCCESS) {
        rc = SMB_ADJOIN_ERR_UPDATE_CNTRL_ATTR;
        goto adjoin_cleanup;
    }

    if (mktemp(tmpfile) == NULL) {
        rc = SMB_ADJOIN_ERR_WRITE_KEYTAB;
        goto adjoin_cleanup;
    }

    encptr = smb_ads_get_enctypes(dclevel, &num);
    if (smb_krb5_kt_populate(ctx, ah->domain, krb5princs, cnt,
        tmpfile, kvno, machine_passwd, encptr, num) != 0) {
        rc = SMB_ADJOIN_ERR_WRITE_KEYTAB;
        goto adjoin_cleanup;
    }

    delete = B_FALSE;
    rc = SMB_ADS_SUCCESS;

adjoin_cleanup:
    if (new_acct && delete)
        smb_ads_del_computer(ah, dn);

    if (rc != SMB_ADJOIN_ERR_INIT_KRB_CTX) {
        if (rc != SMB_ADJOIN_ERR_GET_SPNS)
            smb_krb5_free_kprincs(ctx, krb5princs, cnt);
        smb_krb5_ctx_fini(ctx);
    }

    /* commit keytab file */
    if (rc == SMB_ADS_SUCCESS) {
        if (rename(tmpfile, SMBNS_KRB5_KEYTAB) != 0) {
            (void) unlink(tmpfile);
            rc = SMB_ADJOIN_ERR_COMMIT_KEYTAB;
        }
    } else {
        (void) unlink(tmpfile);
    }

    smb_ads_close(ah);
    smb_ccache_remove(SMB_CCACHE_PATH);
    return (rc);
}

struct xlate_table {
    int err;
    const char const *msg;
};

static const struct xlate_table
adjoin_table[] = {
    { SMB_ADS_SUCCESS, "Success" },
    { SMB_ADS_KRB5_INIT_CTX,
        "Failed creating a Kerberos context." },
    { SMB_ADS_KRB5_CC_DEFAULT,
        "Failed to resolve default credential cache." },
    { SMB_ADS_KRB5_PARSE_PRINCIPAL,
        "Failed parsing the user principal name." },
    { SMB_ADS_KRB5_GET_INIT_CREDS_PW,
        "Failed getting initial credentials.  (Wrong password?)" },
    { SMB_ADS_KRB5_CC_INITIALIZE,
        "Failed initializing the credential cache." },
    { SMB_ADS_KRB5_CC_STORE_CRED,
        "Failed to update the credential cache." },
    { SMB_ADS_CANT_LOCATE_DC,
        "Failed to locate a domain controller." },
    { SMB_ADS_LDAP_INIT,
        "Failed to create an LDAP handle." },
    { SMB_ADS_LDAP_SETOPT,
        "Failed to set an LDAP option." },
    { SMB_ADS_LDAP_SET_DOM,
        "Failed to set the LDAP handle DN." },
    { SMB_ADS_LDAP_SASL_BIND,
        "Failed to bind the LDAP handle. "
        "Usually indicates an authentication problem." },

    { SMB_ADJOIN_ERR_GEN_PWD,
        "Failed to generate machine password." },
    { SMB_ADJOIN_ERR_GET_DCLEVEL, "Unknown functional level of "
        "the domain controller. The rootDSE attribute named "
        "\"domainControllerFunctionality\" is missing from the "
        "Active Directory." },
    { SMB_ADJOIN_ERR_ADD_TRUST_ACCT, "Failed to create the "
        "workstation trust account." },
    { SMB_ADJOIN_ERR_MOD_TRUST_ACCT, "Failed to modify the "
        "workstation trust account." },
    { SMB_ADJOIN_ERR_DUP_TRUST_ACCT, "Failed to create the "
        "workstation trust account because its name is already "
        "in use." },
    { SMB_ADJOIN_ERR_TRUST_ACCT, "Error in querying the "
        "workstation trust account" },
    { SMB_ADJOIN_ERR_INIT_KRB_CTX, "Failed to initialize Kerberos "
        "context." },
    { SMB_ADJOIN_ERR_GET_SPNS, "Failed to get Kerberos "
        "principals." },
    { SMB_ADJOIN_ERR_KSETPWD, "Failed to set machine password." },
    { SMB_ADJOIN_ERR_UPDATE_CNTRL_ATTR,  "Failed to modify "
        "userAccountControl attribute of the workstation trust "
        "account." },
    { SMB_ADJOIN_ERR_WRITE_KEYTAB, "Error in writing to local "
        "keytab file (i.e /etc/krb5/krb5.keytab)." },
    { SMB_ADJOIN_ERR_IDMAP_SET_DOMAIN, "Failed to update idmap "
        "configuration." },
    { SMB_ADJOIN_ERR_IDMAP_REFRESH, "Failed to refresh idmap "
        "service." },
    { SMB_ADJOIN_ERR_COMMIT_KEYTAB, "Failed to commit changes to "
        "local keytab file (i.e. /etc/krb5/krb5.keytab)." },
    { SMB_ADJOIN_ERR_AUTH_NETLOGON,
        "Failed to authenticate using the new computer account." },
    { SMB_ADJOIN_ERR_STORE_PROPS,
        "Failed to store computer account information locally." },
    { 0, NULL }
};

/*
 * smb_ads_strerror
 *
 * Lookup an error message for the specific adjoin error code.
 */
const char *
smb_ads_strerror(int err)
{
    const struct xlate_table *xt;

    if (err > 0 && err < SMB_ADS_ERRNO_GAP)
        return (strerror(err));

    for (xt = adjoin_table; xt->msg; xt++)
        if (xt->err == err)
            return (xt->msg);

    return ("Unknown error code.");
}

void
smb_ads_log_errmsg(smb_ads_status_t err)
{
    const char *s = smb_ads_strerror(err);
    syslog(LOG_NOTICE, "%s", s);
}


/*
 * smb_ads_lookup_msdcs
 *
 * If server argument is set, try to locate the specified DC.
 * If it is set to empty string, locate any DCs in the specified domain.
 * Returns the discovered DC via buf.
 *
 * fqdn   - fully-qualified domain name
 * dci    - the name and address of the found DC
 */
uint32_t
smb_ads_lookup_msdcs(char *fqdn, smb_dcinfo_t *dci)
{
    smb_ads_host_info_t *hinfo = NULL;
    char ipstr[INET6_ADDRSTRLEN];

    if (!fqdn || !dci)
        return (NT_STATUS_INTERNAL_ERROR);

    ipstr[0] = '\0';
    if ((hinfo = smb_ads_find_host(fqdn)) == NULL)
        return (NT_STATUS_DOMAIN_CONTROLLER_NOT_FOUND);

    (void) smb_inet_ntop(&hinfo->ipaddr, ipstr,
        SMB_IPSTRLEN(hinfo->ipaddr.a_family));
    smb_tracef("msdcsLookupADS: %s [%s]", hinfo->name, ipstr);

    (void) strlcpy(dci->dc_name, hinfo->name, sizeof (dci->dc_name));
    dci->dc_addr = hinfo->ipaddr;

    free(hinfo);
    return (NT_STATUS_SUCCESS);
}

static krb5_enctype *
smb_ads_get_enctypes(int dclevel, int *num)
{
    krb5_enctype *encptr;

    if (dclevel >= SMB_ADS_DCLEVEL_W2K8) {
        *num = sizeof (w2k8enctypes) / sizeof (krb5_enctype);
        encptr = w2k8enctypes;
    } else {
        *num = sizeof (pre_w2k8enctypes) / sizeof (krb5_enctype);
        encptr = pre_w2k8enctypes;
    }

    return (encptr);
}