WAF: Fix detection of IPv6

[Samba.git] / lib / krb5_wrap / krb5_samba.c

/*
   Unix SMB/CIFS implementation.
   simple kerberos5 routines for active directory
   Copyright (C) Andrew Tridgell 2001
   Copyright (C) Luke Howard 2002-2003
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005
   Copyright (C) Guenther Deschner 2005-2009

   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 "system/filesys.h"
#include "krb5_samba.h"

#ifdef HAVE_COM_ERR_H
#include <com_err.h>
#endif /* HAVE_COM_ERR_H */

#ifndef KRB5_AUTHDATA_WIN2K_PAC
#define KRB5_AUTHDATA_WIN2K_PAC 128
#endif

#ifndef KRB5_AUTHDATA_IF_RELEVANT
#define KRB5_AUTHDATA_IF_RELEVANT 1
#endif

#ifdef HAVE_KRB5

#define GSSAPI_CHECKSUM      0x8003             /* Checksum type value for Kerberos */
#define GSSAPI_BNDLENGTH     16                 /* Bind Length (rfc-1964 pg.3) */
#define GSSAPI_CHECKSUM_SIZE (4+GSSAPI_BNDLENGTH+4) /* Length of bind length,
                                                        bind field, flags field. */
#define GSS_C_DELEG_FLAG 1

/* MIT krb5 1.7beta3 (in Ubuntu Karmic) is missing the prototype,
   but still has the symbol */
#if !HAVE_DECL_KRB5_AUTH_CON_SET_REQ_CKSUMTYPE
krb5_error_code krb5_auth_con_set_req_cksumtype(
        krb5_context     context,
        krb5_auth_context      auth_context,
        krb5_cksumtype     cksumtype);
#endif

#if !defined(SMB_MALLOC)
#undef malloc
#define SMB_MALLOC(s) malloc((s))
#endif

#ifndef SMB_STRDUP
#define SMB_STRDUP(s) strdup(s)
#endif

/**********************************************************
 * MISSING FUNCTIONS
 **********************************************************/

#if !defined(HAVE_KRB5_SET_DEFAULT_TGS_KTYPES)

#if defined(HAVE_KRB5_SET_DEFAULT_TGS_ENCTYPES)

/* With MIT kerberos, we should use krb5_set_default_tgs_enctypes in preference
 * to krb5_set_default_tgs_ktypes. See
 *         http://lists.samba.org/archive/samba-technical/2006-July/048271.html
 *
 * If the MIT libraries are not exporting internal symbols, we will end up in
 * this branch, which is correct. Otherwise we will continue to use the
 * internal symbol
 */
 krb5_error_code krb5_set_default_tgs_ktypes(krb5_context ctx, const krb5_enctype *enc)
{
    return krb5_set_default_tgs_enctypes(ctx, enc);
}

#elif defined(HAVE_KRB5_SET_DEFAULT_IN_TKT_ETYPES)

/* Heimdal */
 krb5_error_code krb5_set_default_tgs_ktypes(krb5_context ctx, const krb5_enctype *enc)
{
        return krb5_set_default_in_tkt_etypes(ctx, enc);
}

#endif /* HAVE_KRB5_SET_DEFAULT_TGS_ENCTYPES */

#endif /* HAVE_KRB5_SET_DEFAULT_TGS_KTYPES */


#if defined(HAVE_KRB5_AUTH_CON_SETKEY) && !defined(HAVE_KRB5_AUTH_CON_SETUSERUSERKEY)
krb5_error_code krb5_auth_con_setuseruserkey(krb5_context context,
                                             krb5_auth_context auth_context,
                                             krb5_keyblock *keyblock)
{
        return krb5_auth_con_setkey(context, auth_context, keyblock);
}
#endif

#if !defined(HAVE_KRB5_FREE_UNPARSED_NAME)
void krb5_free_unparsed_name(krb5_context context, char *val)
{
        SAFE_FREE(val);
}
#endif

#if defined(HAVE_KRB5_PRINCIPAL_GET_COMP_STRING) && !defined(HAVE_KRB5_PRINC_COMPONENT)
const krb5_data *krb5_princ_component(krb5_context context,
                                      krb5_principal principal, int i);

const krb5_data *krb5_princ_component(krb5_context context,
                                      krb5_principal principal, int i)
{
        static krb5_data kdata;

        kdata.data = discard_const_p(char, krb5_principal_get_comp_string(context, principal, i));
        kdata.length = strlen((const char *)kdata.data);
        return &kdata;
}
#endif


/**********************************************************
 * WRAPPING FUNCTIONS
 **********************************************************/

#if defined(HAVE_ADDR_TYPE_IN_KRB5_ADDRESS)
/* HEIMDAL */

/**
 * @brief Stores the address of a 'struct sockaddr_storage' a krb5_address
 *
 * @param[in]  paddr    A pointer to a 'struct sockaddr_storage to extract the
 *                      address from.
 *
 * @param[out] pkaddr   A Kerberos address to store tha address in.
 *
 * @return True on success, false if an error occured.
 */
bool smb_krb5_sockaddr_to_kaddr(struct sockaddr_storage *paddr,
                                krb5_address *pkaddr)
{
        memset(pkaddr, '\0', sizeof(krb5_address));
#if defined(HAVE_IPV6) && defined(KRB5_ADDRESS_INET6)
        if (paddr->ss_family == AF_INET6) {
                pkaddr->addr_type = KRB5_ADDRESS_INET6;
                pkaddr->address.length = sizeof(((struct sockaddr_in6 *)paddr)->sin6_addr);
                pkaddr->address.data = (char *)&(((struct sockaddr_in6 *)paddr)->sin6_addr);
                return true;
        }
#endif
        if (paddr->ss_family == AF_INET) {
                pkaddr->addr_type = KRB5_ADDRESS_INET;
                pkaddr->address.length = sizeof(((struct sockaddr_in *)paddr)->sin_addr);
                pkaddr->address.data = (char *)&(((struct sockaddr_in *)paddr)->sin_addr);
                return true;
        }
        return false;
}
#elif defined(HAVE_ADDRTYPE_IN_KRB5_ADDRESS)
/* MIT */

/**
 * @brief Stores the address of a 'struct sockaddr_storage' a krb5_address
 *
 * @param[in]  paddr    A pointer to a 'struct sockaddr_storage to extract the
 *                      address from.
 *
 * @param[in]  pkaddr A Kerberos address to store tha address in.
 *
 * @return True on success, false if an error occured.
 */
bool smb_krb5_sockaddr_to_kaddr(struct sockaddr_storage *paddr,
                                krb5_address *pkaddr)
{
        memset(pkaddr, '\0', sizeof(krb5_address));
#if defined(HAVE_IPV6) && defined(ADDRTYPE_INET6)
        if (paddr->ss_family == AF_INET6) {
                pkaddr->addrtype = ADDRTYPE_INET6;
                pkaddr->length = sizeof(((struct sockaddr_in6 *)paddr)->sin6_addr);
                pkaddr->contents = (krb5_octet *)&(((struct sockaddr_in6 *)paddr)->sin6_addr);
                return true;
        }
#endif
        if (paddr->ss_family == AF_INET) {
                pkaddr->addrtype = ADDRTYPE_INET;
                pkaddr->length = sizeof(((struct sockaddr_in *)paddr)->sin_addr);
                pkaddr->contents = (krb5_octet *)&(((struct sockaddr_in *)paddr)->sin_addr);
                return true;
        }
        return false;
}
#else
#error UNKNOWN_ADDRTYPE
#endif

krb5_error_code smb_krb5_mk_error(krb5_context context,
                                  krb5_error_code error_code,
                                  const char *e_text,
                                  krb5_data *e_data,
                                  const krb5_principal client,
                                  const krb5_principal server,
                                  krb5_data *enc_err)
{
        krb5_error_code code = EINVAL;
#ifdef SAMBA4_USES_HEIMDAL
        code = krb5_mk_error(context,
                             error_code,
                             e_text,
                             e_data,
                             client,
                             server,
                             NULL, /* client_time */
                             NULL, /* client_usec */
                             enc_err);
#else
        krb5_principal unspec_server = NULL;
        krb5_error errpkt;

        errpkt.ctime = 0;
        errpkt.cusec = 0;

        code = krb5_us_timeofday(context,
                                 &errpkt.stime,
                                 &errpkt.susec);
        if (code != 0) {
                return code;
        }

        errpkt.error = error_code;

        errpkt.text.length = 0;
        if (e_text != NULL) {
                errpkt.text.length = strlen(e_text);
                errpkt.text.data = discard_const_p(char, e_text);
        }

        errpkt.e_data.magic = KV5M_DATA;
        errpkt.e_data.length = 0;
        errpkt.e_data.data = NULL;
        if (e_data != NULL) {
                errpkt.e_data = *e_data;
        }

        errpkt.client = client;

        if (server != NULL) {
                errpkt.server = server;
        } else {
                code = smb_krb5_make_principal(context,
                                               &unspec_server,
                                               "<unspecified realm>",
                                               NULL);
                if (code != 0) {
                        return code;
                }
                errpkt.server = unspec_server;
        }

        code = krb5_mk_error(context,
                             &errpkt,
                             enc_err);
        krb5_free_principal(context, unspec_server);
#endif
        return code;
}

/**
* @brief Create a keyblock based on input parameters
*
* @param context        The krb5_context
* @param host_princ     The krb5_principal to use
* @param salt           The optional salt, if omitted, salt is calculated with
*                       the provided principal.
* @param password       The krb5_data containing the password
* @param enctype        The krb5_enctype to use for the keyblock generation
* @param key            The returned krb5_keyblock, caller needs to free with
*                       krb5_free_keyblock().
*
* @return krb5_error_code
*/
int smb_krb5_create_key_from_string(krb5_context context,
                                    krb5_const_principal host_princ,
                                    krb5_data *salt,
                                    krb5_data *password,
                                    krb5_enctype enctype,
                                    krb5_keyblock *key)
{
        int ret = 0;

        if (host_princ == NULL && salt == NULL) {
                return -1;
        }

#if defined(HAVE_KRB5_PRINCIPAL2SALT) && defined(HAVE_KRB5_C_STRING_TO_KEY)
{/* MIT */
        krb5_data _salt;

        if (salt == NULL) {
                ret = krb5_principal2salt(context, host_princ, &_salt);
                if (ret) {
                        DEBUG(1,("krb5_principal2salt failed (%s)\n", error_message(ret)));
                        return ret;
                }
        } else {
                _salt = *salt;
        }
        ret = krb5_c_string_to_key(context, enctype, password, &_salt, key);
        if (salt == NULL) {
                SAFE_FREE(_salt.data);
        }
}
#elif defined(HAVE_KRB5_GET_PW_SALT) && defined(HAVE_KRB5_STRING_TO_KEY_SALT)
{/* Heimdal */
        krb5_salt _salt;

        if (salt == NULL) {
                ret = krb5_get_pw_salt(context, host_princ, &_salt);
                if (ret) {
                        DEBUG(1,("krb5_get_pw_salt failed (%s)\n", error_message(ret)));
                        return ret;
                }
        } else {
                _salt.saltvalue = *salt;
                _salt.salttype = KRB5_PW_SALT;
        }

        ret = krb5_string_to_key_salt(context, enctype, (const char *)password->data, _salt, key);
        if (salt == NULL) {
                krb5_free_salt(context, _salt);
        }
}
#else
#error UNKNOWN_CREATE_KEY_FUNCTIONS
#endif
        return ret;
}

/**
* @brief Create a salt for a given principal
*
* @param context        The initialized krb5_context
* @param host_princ     The krb5_principal to create the salt for
* @param psalt          A pointer to a krb5_data struct
*
* caller has to free the contents of psalt with smb_krb5_free_data_contents
* when function has succeeded
*
* @return krb5_error_code, returns 0 on success, error code otherwise
*/

int smb_krb5_get_pw_salt(krb5_context context,
                         krb5_const_principal host_princ,
                         krb5_data *psalt)
#if defined(HAVE_KRB5_GET_PW_SALT)
/* Heimdal */
{
        int ret;
        krb5_salt salt;

        ret = krb5_get_pw_salt(context, host_princ, &salt);
        if (ret) {
                return ret;
        }

        psalt->data = salt.saltvalue.data;
        psalt->length = salt.saltvalue.length;

        return ret;
}
#elif defined(HAVE_KRB5_PRINCIPAL2SALT)
/* MIT */
{
        return krb5_principal2salt(context, host_princ, psalt);
}
#else
#error UNKNOWN_SALT_FUNCTIONS
#endif

#if defined(HAVE_KRB5_GET_PERMITTED_ENCTYPES)
/**
 * @brief Get a list of encryption types allowed for session keys
 *
 * @param[in]  context  The library context
 *
 * @param[in]  enctypes An allocated, zero-terminated list of encryption types
 *
 * This function returns an allocated list of encryption types allowed for
 * session keys.
 *
 * Use free() to free the enctypes when it is no longer needed.
 *
 * @retval 0 Success; otherwise - Kerberos error codes
 */
krb5_error_code smb_krb5_get_allowed_etypes(krb5_context context,
                                            krb5_enctype **enctypes)
{
        return krb5_get_permitted_enctypes(context, enctypes);
}
#elif defined(HAVE_KRB5_GET_DEFAULT_IN_TKT_ETYPES)
krb5_error_code smb_krb5_get_allowed_etypes(krb5_context context,
                                            krb5_enctype **enctypes)
{
#ifdef HAVE_KRB5_PDU_NONE_DECL
        return krb5_get_default_in_tkt_etypes(context, KRB5_PDU_NONE, enctypes);
#else
        return krb5_get_default_in_tkt_etypes(context, enctypes);
#endif
}
#else
#error UNKNOWN_GET_ENCTYPES_FUNCTIONS
#endif


/**
 * @brief Convert a string principal name to a Kerberos principal.
 *
 * @param[in]  context  The library context
 *
 * @param[in]  name     The principal as a unix charset string.
 *
 * @param[out] principal The newly allocated principal.
 *
 * Use krb5_free_principal() to free a principal when it is no longer needed.
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_parse_name(krb5_context context,
                                    const char *name,
                                    krb5_principal *principal)
{
        krb5_error_code ret;
        char *utf8_name;
        size_t converted_size;
        TALLOC_CTX *frame = talloc_stackframe();

        if (!push_utf8_talloc(frame, &utf8_name, name, &converted_size)) {
                talloc_free(frame);
                return ENOMEM;
        }

        ret = krb5_parse_name(context, utf8_name, principal);
        TALLOC_FREE(frame);
        return ret;
}

/**
 * @brief Convert a Kerberos principal structure to a string representation.
 *
 * The resulting string representation will be a unix charset name and is
 * talloc'ed.
 *
 * @param[in]  mem_ctx  The talloc context to allocate memory on.
 *
 * @param[in]  context  The library context.
 *
 * @param[in]  principal The principal.
 *
 * @param[out] unix_name A string representation of the princpial name as with
 *                       unix charset.
 *
 * Use talloc_free() to free the string representation if it is no longer
 * needed.
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_unparse_name(TALLOC_CTX *mem_ctx,
                                      krb5_context context,
                                      krb5_const_principal principal,
                                      char **unix_name)
{
        krb5_error_code ret;
        char *utf8_name;
        size_t converted_size;

        *unix_name = NULL;
        ret = krb5_unparse_name(context, principal, &utf8_name);
        if (ret) {
                return ret;
        }

        if (!pull_utf8_talloc(mem_ctx, unix_name, utf8_name, &converted_size)) {
                krb5_free_unparsed_name(context, utf8_name);
                return ENOMEM;
        }
        krb5_free_unparsed_name(context, utf8_name);
        return 0;
}

/**
 * @brief Free the contents of a krb5_data structure and zero the data field.
 *
 * @param[in]  context  The krb5 context
 *
 * @param[in]  pdata    The data structure to free contents of
 *
 * This function frees the contents, not the structure itself.
 */
void smb_krb5_free_data_contents(krb5_context context, krb5_data *pdata)
{
#if defined(HAVE_KRB5_FREE_DATA_CONTENTS)
        if (pdata->data) {
                krb5_free_data_contents(context, pdata);
        }
#elif defined(HAVE_KRB5_DATA_FREE)
        krb5_data_free(context, pdata);
#else
        SAFE_FREE(pdata->data);
#endif
}

/*
 * @brief copy a buffer into a krb5_data struct
 *
 * @param[in] p                 The krb5_data
 * @param[in] data              The data to copy
 * @param[in] length            The length of the data to copy
 * @return krb5_error_code
 *
 * Caller has to free krb5_data with smb_krb5_free_data_contents().
 */
krb5_error_code smb_krb5_copy_data_contents(krb5_data *p,
                                            const void *data,
                                            size_t len)
{
#if defined(HAVE_KRB5_DATA_COPY)
        return krb5_data_copy(p, data, len);
#else
        if (len) {
                p->data = malloc(len);
                if (p->data == NULL) {
                        return ENOMEM;
                }
                memmove(p->data, data, len);
        } else {
                p->data = NULL;
        }
        p->length = len;
        p->magic = KV5M_DATA;
        return 0;
#endif
}

bool smb_krb5_get_smb_session_key(TALLOC_CTX *mem_ctx,
                                  krb5_context context,
                                  krb5_auth_context auth_context,
                                  DATA_BLOB *session_key,
                                  bool remote)
{
        krb5_keyblock *skey = NULL;
        krb5_error_code err = 0;
        bool ret = false;

        if (remote) {
#ifdef HAVE_KRB5_AUTH_CON_GETRECVSUBKEY
                err = krb5_auth_con_getrecvsubkey(context,
                                                  auth_context,
                                                  &skey);
#else /* HAVE_KRB5_AUTH_CON_GETRECVSUBKEY */
                err = krb5_auth_con_getremotesubkey(context,
                                                    auth_context, &skey);
#endif /* HAVE_KRB5_AUTH_CON_GETRECVSUBKEY */
        } else {
#ifdef HAVE_KRB5_AUTH_CON_GETSENDSUBKEY
                err = krb5_auth_con_getsendsubkey(context,
                                                  auth_context,
                                                  &skey);
#else /* HAVE_KRB5_AUTH_CON_GETSENDSUBKEY */
                err = krb5_auth_con_getlocalsubkey(context,
                                                   auth_context, &skey);
#endif /* HAVE_KRB5_AUTH_CON_GETSENDSUBKEY */
        }

        if (err || skey == NULL) {
                DEBUG(10, ("KRB5 error getting session key %d\n", err));
                goto done;
        }

        DEBUG(10, ("Got KRB5 session key of length %d\n",
                   (int)KRB5_KEY_LENGTH(skey)));

        *session_key = data_blob_talloc(mem_ctx,
                                         KRB5_KEY_DATA(skey),
                                         KRB5_KEY_LENGTH(skey));
        dump_data_pw("KRB5 Session Key:\n",
                     session_key->data,
                     session_key->length);

        ret = true;

done:
        if (skey) {
                krb5_free_keyblock(context, skey);
        }

        return ret;
}


/**
 * @brief Get talloced string component of a principal
 *
 * @param[in] mem_ctx           The TALLOC_CTX
 * @param[in] context           The krb5_context
 * @param[in] principal         The principal
 * @param[in] component         The component
 * @return string component
 *
 * Caller must talloc_free if the return value is not NULL.
 *
 */
char *smb_krb5_principal_get_comp_string(TALLOC_CTX *mem_ctx,
                                         krb5_context context,
                                         krb5_const_principal principal,
                                         unsigned int component)
{
#if defined(HAVE_KRB5_PRINCIPAL_GET_COMP_STRING)
        return talloc_strdup(mem_ctx, krb5_principal_get_comp_string(context, principal, component));
#else
        krb5_data *data;

        if (component >= krb5_princ_size(context, principal)) {
                return NULL;
        }

        data = krb5_princ_component(context, principal, component);
        if (data == NULL) {
                return NULL;
        }

        return talloc_strndup(mem_ctx, data->data, data->length);
#endif
}

/**
 * @brief
 *
 * @param[in]  ccache_string A string pointing to the cache to renew the ticket
 *                           (e.g. FILE:/tmp/krb5cc_0) or NULL. If the principal
 *                           ccache has not been specified, the default ccache
 *                           will be used.
 *
 * @param[in]  client_string The client principal string (e.g. user@SAMBA.SITE)
 *                           or NULL. If the principal string has not been
 *                           specified, the principal from the ccache will be
 *                           retrieved.
 *
 * @param[in]  service_string The service ticket string
 *                            (e.g. krbtgt/SAMBA.SITE@SAMBA.SITE) or NULL. If
 *                            the sevice ticket is specified, it is parsed (
 *                            with the realm part ignored) and used as the
 *                            server principal of the credential. Otherwise
 *                            the ticket-granting service is used.
 *
 * @param[in]  expire_time    A pointer to store the credentials end time or
 *                            NULL.
 *
 * @return 0 on Succes, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_renew_ticket(const char *ccache_string,
                                      const char *client_string,
                                      const char *service_string,
                                      time_t *expire_time)
{
        krb5_error_code ret;
        krb5_context context = NULL;
        krb5_ccache ccache = NULL;
        krb5_principal client = NULL;
        krb5_creds creds, creds_in;

        ZERO_STRUCT(creds);
        ZERO_STRUCT(creds_in);

        initialize_krb5_error_table();
        ret = krb5_init_context(&context);
        if (ret) {
                goto done;
        }

        if (!ccache_string) {
                ccache_string = krb5_cc_default_name(context);
        }

        if (!ccache_string) {
                ret = EINVAL;
                goto done;
        }

        DEBUG(10,("smb_krb5_renew_ticket: using %s as ccache\n", ccache_string));

        /* FIXME: we should not fall back to defaults */
        ret = krb5_cc_resolve(context, discard_const_p(char, ccache_string), &ccache);
        if (ret) {
                goto done;
        }

        if (client_string) {
                ret = smb_krb5_parse_name(context, client_string, &client);
                if (ret) {
                        goto done;
                }
        } else {
                ret = krb5_cc_get_principal(context, ccache, &client);
                if (ret) {
                        goto done;
                }
        }

        ret = krb5_get_renewed_creds(context, &creds, client, ccache, discard_const_p(char, service_string));
        if (ret) {
                DEBUG(10,("smb_krb5_renew_ticket: krb5_get_kdc_cred failed: %s\n", error_message(ret)));
                goto done;
        }

        /* hm, doesn't that create a new one if the old one wasn't there? - Guenther */
        ret = krb5_cc_initialize(context, ccache, client);
        if (ret) {
                goto done;
        }

        ret = krb5_cc_store_cred(context, ccache, &creds);

        if (expire_time) {
                *expire_time = (time_t) creds.times.endtime;
        }

done:
        krb5_free_cred_contents(context, &creds_in);
        krb5_free_cred_contents(context, &creds);

        if (client) {
                krb5_free_principal(context, client);
        }
        if (ccache) {
                krb5_cc_close(context, ccache);
        }
        if (context) {
                krb5_free_context(context);
        }

        return ret;
}

/**
 * @brief Free the data stored in an smb_krb5_addresses structure.
 *
 * @param[in]  context  The library context
 *
 * @param[in]  addr     The address structure to free.
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_free_addresses(krb5_context context,
                                        smb_krb5_addresses *addr)
{
        krb5_error_code ret = 0;
        if (addr == NULL) {
                return ret;
        }
#if defined(HAVE_MAGIC_IN_KRB5_ADDRESS) && defined(HAVE_ADDRTYPE_IN_KRB5_ADDRESS) /* MIT */
        krb5_free_addresses(context, addr->addrs);
#elif defined(HAVE_ADDR_TYPE_IN_KRB5_ADDRESS) /* Heimdal */
        ret = krb5_free_addresses(context, addr->addrs);
        SAFE_FREE(addr->addrs);
#endif
        SAFE_FREE(addr);
        addr = NULL;
        return ret;
}

#define MAX_NETBIOSNAME_LEN 16

/**
 * @brief Add a netbios name to the array of addresses
 *
 * @param[in]  kerb_addr A pointer to the smb_krb5_addresses to add the
 *                       netbios name to.
 *
 * @param[in]  netbios_name The netbios name to add.
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_gen_netbios_krb5_address(smb_krb5_addresses **kerb_addr,
                                                   const char *netbios_name)
{
        krb5_error_code ret = 0;
        char buf[MAX_NETBIOSNAME_LEN];
        int len;
#if defined(HAVE_MAGIC_IN_KRB5_ADDRESS) && defined(HAVE_ADDRTYPE_IN_KRB5_ADDRESS) /* MIT */
        krb5_address **addrs = NULL;
#elif defined(HAVE_ADDR_TYPE_IN_KRB5_ADDRESS) /* Heimdal */
        krb5_addresses *addrs = NULL;
#endif

        *kerb_addr = (smb_krb5_addresses *)SMB_MALLOC(sizeof(smb_krb5_addresses));
        if (*kerb_addr == NULL) {
                return ENOMEM;
        }

        /* temporarily duplicate put_name() code here to avoid dependency
         * issues for a 5 lines function */
        len = strlen(netbios_name);
        memcpy(buf, netbios_name,
                (len < MAX_NETBIOSNAME_LEN) ? len : MAX_NETBIOSNAME_LEN - 1);
        if (len < MAX_NETBIOSNAME_LEN - 1) {
                memset(buf + len, ' ', MAX_NETBIOSNAME_LEN - 1 - len);
        }
        buf[MAX_NETBIOSNAME_LEN - 1] = 0x20;

#if defined(HAVE_MAGIC_IN_KRB5_ADDRESS) && defined(HAVE_ADDRTYPE_IN_KRB5_ADDRESS) /* MIT */
        {
                int num_addr = 2;

                addrs = (krb5_address **)SMB_MALLOC(sizeof(krb5_address *) * num_addr);
                if (addrs == NULL) {
                        SAFE_FREE(*kerb_addr);
                        return ENOMEM;
                }

                memset(addrs, 0, sizeof(krb5_address *) * num_addr);

                addrs[0] = (krb5_address *)SMB_MALLOC(sizeof(krb5_address));
                if (addrs[0] == NULL) {
                        SAFE_FREE(addrs);
                        SAFE_FREE(*kerb_addr);
                        return ENOMEM;
                }

                addrs[0]->magic = KV5M_ADDRESS;
                addrs[0]->addrtype = KRB5_ADDR_NETBIOS;
                addrs[0]->length = MAX_NETBIOSNAME_LEN;
                addrs[0]->contents = (unsigned char *)SMB_MALLOC(addrs[0]->length);
                if (addrs[0]->contents == NULL) {
                        SAFE_FREE(addrs[0]);
                        SAFE_FREE(addrs);
                        SAFE_FREE(*kerb_addr);
                        return ENOMEM;
                }

                memcpy(addrs[0]->contents, buf, addrs[0]->length);

                addrs[1] = NULL;
        }
#elif defined(HAVE_ADDR_TYPE_IN_KRB5_ADDRESS) /* Heimdal */
        {
                addrs = (krb5_addresses *)SMB_MALLOC(sizeof(krb5_addresses));
                if (addrs == NULL) {
                        SAFE_FREE(*kerb_addr);
                        return ENOMEM;
                }

                memset(addrs, 0, sizeof(krb5_addresses));

                addrs->len = 1;
                addrs->val = (krb5_address *)SMB_MALLOC(sizeof(krb5_address));
                if (addrs->val == NULL) {
                        SAFE_FREE(addrs);
                        SAFE_FREE(kerb_addr);
                        return ENOMEM;
                }

                addrs->val[0].addr_type = KRB5_ADDR_NETBIOS;
                addrs->val[0].address.length = MAX_NETBIOSNAME_LEN;
                addrs->val[0].address.data = (unsigned char *)SMB_MALLOC(addrs->val[0].address.length);
                if (addrs->val[0].address.data == NULL) {
                        SAFE_FREE(addrs->val);
                        SAFE_FREE(addrs);
                        SAFE_FREE(*kerb_addr);
                        return ENOMEM;
                }

                memcpy(addrs->val[0].address.data, buf, addrs->val[0].address.length);
        }
#else
#error UNKNOWN_KRB5_ADDRESS_FORMAT
#endif
        (*kerb_addr)->addrs = addrs;

        return ret;
}

/**
 * @brief Get the enctype from a key table entry
 *
 * @param[in]  kt_entry Key table entry to get the enctype from.
 *
 * @return The enctype from the entry.
 */
krb5_enctype smb_krb5_kt_get_enctype_from_entry(krb5_keytab_entry *kt_entry)
{
        return KRB5_KEY_TYPE(KRB5_KT_KEY(kt_entry));
}

/**
 * @brief Free the contents of a key table entry.
 *
 * @param[in]  context The library context.
 *
 * @param[in]  kt_entry The key table entry to free the contents of.
 *
 * @return 0 on success, a Kerberos error code otherwise.
 *
 * The pointer itself is not freed.
 */
krb5_error_code smb_krb5_kt_free_entry(krb5_context context,
                                        krb5_keytab_entry *kt_entry)
{
/* Try krb5_free_keytab_entry_contents first, since
 * MIT Kerberos >= 1.7 has both krb5_free_keytab_entry_contents and
 * krb5_kt_free_entry but only has a prototype for the first, while the
 * second is considered private.
 */
#if defined(HAVE_KRB5_FREE_KEYTAB_ENTRY_CONTENTS)
        return krb5_free_keytab_entry_contents(context, kt_entry);
#elif defined(HAVE_KRB5_KT_FREE_ENTRY)
        return krb5_kt_free_entry(context, kt_entry);
#else
#error UNKNOWN_KT_FREE_FUNCTION
#endif
}


/**
 * @brief Convert an encryption type to a string.
 *
 * @param[in]  context The library context.
 *
 * @param[in]  enctype The encryption type.
 *
 * @param[in]  etype_s A pointer to store the allocated encryption type as a
 *                     string.
 *
 * @return 0 on success, a Kerberos error code otherwise.
 *
 * The caller needs to free the allocated string etype_s.
 */
krb5_error_code smb_krb5_enctype_to_string(krb5_context context,
                                           krb5_enctype enctype,
                                           char **etype_s)
{
#ifdef HAVE_KRB5_ENCTYPE_TO_STRING_WITH_KRB5_CONTEXT_ARG
        return krb5_enctype_to_string(context, enctype, etype_s); /* Heimdal */
#elif defined(HAVE_KRB5_ENCTYPE_TO_STRING_WITH_SIZE_T_ARG)
        char buf[256];
        krb5_error_code ret = krb5_enctype_to_string(enctype, buf, 256); /* MIT */
        if (ret) {
                return ret;
        }
        *etype_s = SMB_STRDUP(buf);
        if (!*etype_s) {
                return ENOMEM;
        }
        return ret;
#else
#error UNKNOWN_KRB5_ENCTYPE_TO_STRING_FUNCTION
#endif
}

/* This MAX_NAME_LEN is a constant defined in krb5.h */
#ifndef MAX_KEYTAB_NAME_LEN
#define MAX_KEYTAB_NAME_LEN 1100
#endif

/**
 * @brief Open a key table readonly or with readwrite access.
 *
 * Allows to use a different keytab than the default one using a relative
 * path to the keytab.
 *
 * @param[in]  context  The library context
 *
 * @param[in]  keytab_name_req The path to the key table.
 *
 * @param[in]  write_access Open with readwrite access.
 *
 * @param[in]  keytab A pointer o the opended key table.
 *
 * The keytab pointer should be freed using krb5_kt_close().
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_kt_open_relative(krb5_context context,
                                          const char *keytab_name_req,
                                          bool write_access,
                                          krb5_keytab *keytab)
{
        krb5_error_code ret = 0;
        TALLOC_CTX *mem_ctx;
        char keytab_string[MAX_KEYTAB_NAME_LEN];
        char *kt_str = NULL;
        bool found_valid_name = false;
        const char *pragma = "FILE";
        const char *tmp = NULL;

        if (!write_access && !keytab_name_req) {
                /* caller just wants to read the default keytab readonly, so be it */
                return krb5_kt_default(context, keytab);
        }

        mem_ctx = talloc_init("smb_krb5_open_keytab");
        if (!mem_ctx) {
                return ENOMEM;
        }

#ifdef HAVE_WRFILE_KEYTAB
        if (write_access) {
                pragma = "WRFILE";
        }
#endif

        if (keytab_name_req) {

                if (strlen(keytab_name_req) > MAX_KEYTAB_NAME_LEN) {
                        ret = KRB5_CONFIG_NOTENUFSPACE;
                        goto out;
                }

                if ((strncmp(keytab_name_req, "WRFILE:", 7) == 0) ||
                    (strncmp(keytab_name_req, "FILE:", 5) == 0)) {
                        tmp = keytab_name_req;
                        goto resolve;
                }

                tmp = talloc_asprintf(mem_ctx, "%s:%s", pragma, keytab_name_req);
                if (!tmp) {
                        ret = ENOMEM;
                        goto out;
                }

                goto resolve;
        }

        /* we need to handle more complex keytab_strings, like:
         * "ANY:FILE:/etc/krb5.keytab,krb4:/etc/srvtab" */

        ret = krb5_kt_default_name(context, &keytab_string[0], MAX_KEYTAB_NAME_LEN - 2);
        if (ret) {
                goto out;
        }

        DEBUG(10,("smb_krb5_open_keytab: krb5_kt_default_name returned %s\n", keytab_string));

        tmp = talloc_strdup(mem_ctx, keytab_string);
        if (!tmp) {
                ret = ENOMEM;
                goto out;
        }

        if (strncmp(tmp, "ANY:", 4) == 0) {
                tmp += 4;
        }

        memset(&keytab_string, '\0', sizeof(keytab_string));

        while (next_token_talloc(mem_ctx, &tmp, &kt_str, ",")) {
                if (strncmp(kt_str, "WRFILE:", 7) == 0) {
                        found_valid_name = true;
                        tmp = kt_str;
                        tmp += 7;
                }

                if (strncmp(kt_str, "FILE:", 5) == 0) {
                        found_valid_name = true;
                        tmp = kt_str;
                        tmp += 5;
                }

                if (tmp[0] == '/') {
                        /* Treat as a FILE: keytab definition. */
                        found_valid_name = true;
                }

                if (found_valid_name) {
                        if (tmp[0] != '/') {
                                ret = KRB5_KT_BADNAME;
                                goto out;
                        }

                        tmp = talloc_asprintf(mem_ctx, "%s:%s", pragma, tmp);
                        if (!tmp) {
                                ret = ENOMEM;
                                goto out;
                        }
                        break;
                }
        }

        if (!found_valid_name) {
                ret = KRB5_KT_UNKNOWN_TYPE;
                goto out;
        }

resolve:
        DEBUG(10,("smb_krb5_open_keytab: resolving: %s\n", tmp));
        ret = krb5_kt_resolve(context, tmp, keytab);

out:
        TALLOC_FREE(mem_ctx);
        return ret;
}

/**
 * @brief Open a key table readonly or with readwrite access.
 *
 * Allows to use a different keytab than the default one. The path needs to be
 * an absolute path or an error will be returned.
 *
 * @param[in]  context  The library context
 *
 * @param[in]  keytab_name_req The path to the key table.
 *
 * @param[in]  write_access Open with readwrite access.
 *
 * @param[in]  keytab A pointer o the opended key table.
 *
 * The keytab pointer should be freed using krb5_kt_close().
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_kt_open(krb5_context context,
                                 const char *keytab_name_req,
                                 bool write_access,
                                 krb5_keytab *keytab)
{
        int cmp;

        if (keytab_name_req == NULL) {
                return KRB5_KT_BADNAME;
        }

        if (keytab_name_req[0] == '/') {
                goto open_keytab;
        }

        cmp = strncmp(keytab_name_req, "FILE:/", 6);
        if (cmp == 0) {
                goto open_keytab;
        }

        cmp = strncmp(keytab_name_req, "WRFILE:/", 8);
        if (cmp == 0) {
                goto open_keytab;
        }

        return KRB5_KT_BADNAME;

open_keytab:
        return smb_krb5_kt_open_relative(context,
                                         keytab_name_req,
                                         write_access,
                                         keytab);
}

/**
 * @brief Get a key table name.
 *
 * @param[in]  mem_ctx The talloc context to use for allocation.
 *
 * @param[in]  context The library context.
 *
 * @param[in]  keytab The key table to get the name from.
 *
 * @param[in]  keytab_name A talloc'ed string of the key table name.
 *
 * The talloc'ed name string needs to be freed with talloc_free().
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_kt_get_name(TALLOC_CTX *mem_ctx,
                                     krb5_context context,
                                     krb5_keytab keytab,
                                     const char **keytab_name)
{
        char keytab_string[MAX_KEYTAB_NAME_LEN];
        krb5_error_code ret = 0;

        ret = krb5_kt_get_name(context, keytab,
                               keytab_string, MAX_KEYTAB_NAME_LEN - 2);
        if (ret) {
                return ret;
        }

        *keytab_name = talloc_strdup(mem_ctx, keytab_string);
        if (!*keytab_name) {
                return ENOMEM;
        }

        return ret;
}

/**
 * @brief Seek and delete old entries in a keytab based on the passed
 *        principal.
 *
 * @param[in]  context       The KRB5 context to use.
 *
 * @param[in]  keytab        The keytab to operate on.
 *
 * @param[in]  kvno          The kvnco to use.
 *
 * @param[in]  princ_s       The principal as a string to search for.
 *
 * @param[in]  princ         The principal as a krb5_principal to search for.
 *
 * @param[in]  flush         Weather to flush the complete keytab.
 *
 * @param[in]  keep_old_entries Keep the entry with the previous kvno.
 *
 * @retval 0 on Sucess
 *
 * @return An appropriate KRB5 error code.
 */
krb5_error_code smb_krb5_kt_seek_and_delete_old_entries(krb5_context context,
                                                        krb5_keytab keytab,
                                                        krb5_kvno kvno,
                                                        krb5_enctype enctype,
                                                        const char *princ_s,
                                                        krb5_principal princ,
                                                        bool flush,
                                                        bool keep_old_entries)
{
        krb5_error_code ret;
        krb5_kt_cursor cursor;
        krb5_kt_cursor zero_csr;
        krb5_keytab_entry kt_entry;
        krb5_keytab_entry zero_kt_entry;
        char *ktprinc = NULL;
        krb5_kvno old_kvno = kvno - 1;
        TALLOC_CTX *tmp_ctx;

        ZERO_STRUCT(cursor);
        ZERO_STRUCT(zero_csr);
        ZERO_STRUCT(kt_entry);
        ZERO_STRUCT(zero_kt_entry);

        ret = krb5_kt_start_seq_get(context, keytab, &cursor);
        if (ret == KRB5_KT_END || ret == ENOENT ) {
                /* no entries */
                return 0;
        }

        tmp_ctx = talloc_new(NULL);
        if (tmp_ctx == NULL) {
                return ENOMEM;
        }

        DEBUG(3, (__location__ ": Will try to delete old keytab entries\n"));
        while (!krb5_kt_next_entry(context, keytab, &kt_entry, &cursor)) {
                bool name_ok = false;
                krb5_enctype kt_entry_enctype =
                        smb_krb5_kt_get_enctype_from_entry(&kt_entry);

                if (!flush && (princ_s != NULL)) {
                        ret = smb_krb5_unparse_name(tmp_ctx, context,
                                                    kt_entry.principal,
                                                    &ktprinc);
                        if (ret) {
                                DEBUG(1, (__location__
                                          ": smb_krb5_unparse_name failed "
                                          "(%s)\n", error_message(ret)));
                                goto out;
                        }

#ifdef HAVE_KRB5_KT_COMPARE
                        name_ok = krb5_kt_compare(context, &kt_entry,
                                                  princ, 0, 0);
#else
                        name_ok = (strcmp(ktprinc, princ_s) == 0);
#endif

                        if (!name_ok) {
                                DEBUG(10, (__location__ ": ignoring keytab "
                                           "entry principal %s, kvno = %d\n",
                                           ktprinc, kt_entry.vno));

                                /* Not a match,
                                 * just free this entry and continue. */
                                ret = smb_krb5_kt_free_entry(context,
                                                             &kt_entry);
                                ZERO_STRUCT(kt_entry);
                                if (ret) {
                                        DEBUG(1, (__location__
                                                  ": smb_krb5_kt_free_entry "
                                                  "failed (%s)\n",
                                                  error_message(ret)));
                                        goto out;
                                }

                                TALLOC_FREE(ktprinc);
                                continue;
                        }

                        TALLOC_FREE(ktprinc);
                }

                /*------------------------------------------------------------
                 * Save the entries with kvno - 1. This is what microsoft does
                 * to allow people with existing sessions that have kvno - 1
                 * to still work. Otherwise, when the password for the machine
                 * changes, all kerberizied sessions will 'break' until either
                 * the client reboots or the client's session key expires and
                 * they get a new session ticket with the new kvno.
                 * Some keytab files only store the kvno in 8bits, limit
                 * the compare accordingly.
                 */

                if (!flush && ((kt_entry.vno & 0xff) == (old_kvno & 0xff))) {
                        DEBUG(5, (__location__ ": Saving previous (kvno %d) "
                                  "entry for principal: %s.\n",
                                  old_kvno, princ_s));
                        continue;
                }

                if (keep_old_entries) {
                        DEBUG(5, (__location__ ": Saving old (kvno %d) "
                                  "entry for principal: %s.\n",
                                  kvno, princ_s));
                        continue;
                }

                if (!flush &&
                    (kt_entry.vno == kvno) &&
                    (kt_entry_enctype != enctype))
                {
                        DEBUG(5, (__location__ ": Saving entry with kvno [%d] "
                                  "enctype [%d] for principal: %s.\n",
                                  kvno, kt_entry_enctype, princ_s));
                        continue;
                }

                DEBUG(5, (__location__ ": Found old entry for principal: %s "
                          "(kvno %d) - trying to remove it.\n",
                          princ_s, kt_entry.vno));

                ret = krb5_kt_end_seq_get(context, keytab, &cursor);
                ZERO_STRUCT(cursor);
                if (ret) {
                        DEBUG(1, (__location__ ": krb5_kt_end_seq_get() "
                                  "failed (%s)\n", error_message(ret)));
                        goto out;
                }
                ret = krb5_kt_remove_entry(context, keytab, &kt_entry);
                if (ret) {
                        DEBUG(1, (__location__ ": krb5_kt_remove_entry() "
                                  "failed (%s)\n", error_message(ret)));
                        goto out;
                }

                DEBUG(5, (__location__ ": removed old entry for principal: "
                          "%s (kvno %d).\n", princ_s, kt_entry.vno));

                ret = krb5_kt_start_seq_get(context, keytab, &cursor);
                if (ret) {
                        DEBUG(1, (__location__ ": krb5_kt_start_seq() failed "
                                  "(%s)\n", error_message(ret)));
                        goto out;
                }
                ret = smb_krb5_kt_free_entry(context, &kt_entry);
                ZERO_STRUCT(kt_entry);
                if (ret) {
                        DEBUG(1, (__location__ ": krb5_kt_remove_entry() "
                                  "failed (%s)\n", error_message(ret)));
                        goto out;
                }
        }

out:
        talloc_free(tmp_ctx);
        if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
                smb_krb5_kt_free_entry(context, &kt_entry);
        }
        if (memcmp(&cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) {
                krb5_kt_end_seq_get(context, keytab, &cursor);
        }
        return ret;
}

/**
 * @brief Add a keytab entry for the given principal
 *
 * @param[in]  context       The krb5 context to use.
 *
 * @param[in]  keytab        The keytab to add the entry to.
 *
 * @param[in]  kvno          The kvno to use.
 *
 * @param[in]  princ_s       The principal as a string.
 *
 * @param[in]  salt_principal The salt principal to salt the password with.
 *                            Only needed for keys which support salting.
 *                            If no salt is used set no_salt to false and
 *                            pass NULL here.
 *
 * @param[in]  enctype        The encryption type of the keytab entry.
 *
 * @param[in]  password       The password of the keytab entry.
 *
 * @param[in]  no_salt        If the password should not be salted. Normally
 *                            this is only set to false for encryption types
 *                            which do not support salting like RC4.
 *
 * @param[in]  keep_old_entries Wether to keep or delte old keytab entries.
 *
 * @retval 0 on Success
 *
 * @return A corresponding KRB5 error code.
 *
 * @see smb_krb5_kt_open()
 */
krb5_error_code smb_krb5_kt_add_entry(krb5_context context,
                                      krb5_keytab keytab,
                                      krb5_kvno kvno,
                                      const char *princ_s,
                                      const char *salt_principal,
                                      krb5_enctype enctype,
                                      krb5_data *password,
                                      bool no_salt,
                                      bool keep_old_entries)
{
        krb5_error_code ret;
        krb5_keytab_entry kt_entry;
        krb5_principal princ = NULL;
        krb5_keyblock *keyp;

        ZERO_STRUCT(kt_entry);

        ret = smb_krb5_parse_name(context, princ_s, &princ);
        if (ret) {
                DEBUG(1, (__location__ ": smb_krb5_parse_name(%s) "
                          "failed (%s)\n", princ_s, error_message(ret)));
                goto out;
        }

        /* Seek and delete old keytab entries */
        ret = smb_krb5_kt_seek_and_delete_old_entries(context,
                                                      keytab,
                                                      kvno,
                                                      enctype,
                                                      princ_s,
                                                      princ,
                                                      false,
                                                      keep_old_entries);
        if (ret) {
                goto out;
        }

        /* If we get here, we have deleted all the old entries with kvno's
         * not equal to the current kvno-1. */

        keyp = KRB5_KT_KEY(&kt_entry);

        if (no_salt) {
                KRB5_KEY_DATA(keyp) = (KRB5_KEY_DATA_CAST *)SMB_MALLOC(password->length);
                if (KRB5_KEY_DATA(keyp) == NULL) {
                        ret = ENOMEM;
                        goto out;
                }
                memcpy(KRB5_KEY_DATA(keyp), password->data, password->length);
                KRB5_KEY_LENGTH(keyp) = password->length;
                KRB5_KEY_TYPE(keyp) = enctype;
        } else {
                krb5_principal salt_princ = NULL;

                /* Now add keytab entries for all encryption types */
                ret = smb_krb5_parse_name(context, salt_principal, &salt_princ);
                if (ret) {
                        DBG_WARNING("krb5_parse_name(%s) failed (%s)\n",
                                    salt_principal, error_message(ret));
                        goto out;
                }

                ret = smb_krb5_create_key_from_string(context,
                                                      salt_princ,
                                                      NULL,
                                                      password,
                                                      enctype,
                                                      keyp);
                krb5_free_principal(context, salt_princ);
                if (ret != 0) {
                        goto out;
                }
        }

        kt_entry.principal = princ;
        kt_entry.vno       = kvno;

        DEBUG(3, (__location__ ": adding keytab entry for (%s) with "
                  "encryption type (%d) and version (%d)\n",
                  princ_s, enctype, kt_entry.vno));
        ret = krb5_kt_add_entry(context, keytab, &kt_entry);
        krb5_free_keyblock_contents(context, keyp);
        ZERO_STRUCT(kt_entry);
        if (ret) {
                DEBUG(1, (__location__ ": adding entry to keytab "
                          "failed (%s)\n", error_message(ret)));
                goto out;
        }

out:
        if (princ) {
                krb5_free_principal(context, princ);
        }

        return ret;
}

#if defined(HAVE_KRB5_GET_CREDS_OPT_SET_IMPERSONATE) && \
    defined(HAVE_KRB5_GET_CREDS_OPT_ALLOC) && \
    defined(HAVE_KRB5_GET_CREDS)
static krb5_error_code smb_krb5_get_credentials_for_user_opt(krb5_context context,
                                                             krb5_ccache ccache,
                                                             krb5_principal me,
                                                             krb5_principal server,
                                                             krb5_principal impersonate_princ,
                                                             krb5_creds **out_creds)
{
        krb5_error_code ret;
        krb5_get_creds_opt opt;

        ret = krb5_get_creds_opt_alloc(context, &opt);
        if (ret) {
                goto done;
        }
        krb5_get_creds_opt_add_options(context, opt, KRB5_GC_FORWARDABLE);

        if (impersonate_princ) {
                ret = krb5_get_creds_opt_set_impersonate(context, opt,
                                                         impersonate_princ);
                if (ret) {
                        goto done;
                }
        }

        ret = krb5_get_creds(context, opt, ccache, server, out_creds);
        if (ret) {
                goto done;
        }

 done:
        if (opt) {
                krb5_get_creds_opt_free(context, opt);
        }
        return ret;
}
#endif /* HAVE_KRB5_GET_CREDS_OPT_SET_IMPERSONATE */

#ifdef HAVE_KRB5_GET_CREDENTIALS_FOR_USER

#if !HAVE_DECL_KRB5_GET_CREDENTIALS_FOR_USER
krb5_error_code KRB5_CALLCONV
krb5_get_credentials_for_user(krb5_context context, krb5_flags options,
                              krb5_ccache ccache, krb5_creds *in_creds,
                              krb5_data *subject_cert,
                              krb5_creds **out_creds);
#endif /* !HAVE_DECL_KRB5_GET_CREDENTIALS_FOR_USER */

static krb5_error_code smb_krb5_get_credentials_for_user(krb5_context context,
                                                         krb5_ccache ccache,
                                                         krb5_principal me,
                                                         krb5_principal server,
                                                         krb5_principal impersonate_princ,
                                                         krb5_creds **out_creds)
{
        krb5_error_code ret;
        krb5_creds in_creds;

        ZERO_STRUCT(in_creds);

        if (impersonate_princ) {

                in_creds.server = me;
                in_creds.client = impersonate_princ;

                ret = krb5_get_credentials_for_user(context,
                                                    0, /* krb5_flags options */
                                                    ccache,
                                                    &in_creds,
                                                    NULL, /* krb5_data *subject_cert */
                                                    out_creds);
        } else {
                in_creds.client = me;
                in_creds.server = server;

                ret = krb5_get_credentials(context, 0, ccache,
                                           &in_creds, out_creds);
        }

        return ret;
}
#endif /* HAVE_KRB5_GET_CREDENTIALS_FOR_USER */

/*
 * smb_krb5_get_credentials
 *
 * @brief Get krb5 credentials for a server
 *
 * @param[in] context           An initialized krb5_context
 * @param[in] ccache            An initialized krb5_ccache
 * @param[in] me                The krb5_principal of the caller
 * @param[in] server            The krb5_principal of the requested service
 * @param[in] impersonate_princ The krb5_principal of a user to impersonate as (optional)
 * @param[out] out_creds        The returned krb5_creds structure
 * @return krb5_error_code
 *
 */
krb5_error_code smb_krb5_get_credentials(krb5_context context,
                                         krb5_ccache ccache,
                                         krb5_principal me,
                                         krb5_principal server,
                                         krb5_principal impersonate_princ,
                                         krb5_creds **out_creds)
{
        krb5_error_code ret;
        krb5_creds *creds = NULL;

        if (out_creds != NULL) {
                *out_creds = NULL;
        }

        if (impersonate_princ) {
#ifdef HAVE_KRB5_GET_CREDS_OPT_SET_IMPERSONATE /* Heimdal */
                ret = smb_krb5_get_credentials_for_user_opt(context, ccache, me, server, impersonate_princ, &creds);
#elif defined(HAVE_KRB5_GET_CREDENTIALS_FOR_USER) /* MIT */
                ret = smb_krb5_get_credentials_for_user(context, ccache, me, server, impersonate_princ, &creds);
#else
                ret = ENOTSUP;
#endif
        } else {
                krb5_creds in_creds;

                ZERO_STRUCT(in_creds);

                in_creds.client = me;
                in_creds.server = server;

                ret = krb5_get_credentials(context, 0, ccache,
                                           &in_creds, &creds);
        }
        if (ret) {
                goto done;
        }

        if (out_creds) {
                *out_creds = creds;
        }

 done:
        if (creds && ret) {
                krb5_free_creds(context, creds);
        }

        return ret;
}

/**
 * @brief Initialize a krb5_keyblock with the given data.
 *
 * Initialized a new keyblock, allocates the contents fo the key and
 * copies the data into the keyblock.
 *
 * @param[in]  context  The library context
 *
 * @param[in]  enctype  The encryption type.
 *
 * @param[in]  data     The date to initialize the keyblock with.
 *
 * @param[in]  length   The length of the keyblock.
 *
 * @param[in]  key      Newly allocated keyblock structure.
 *
 * The key date must be freed using krb5_free_keyblock_contents() when it is
 * no longer needed.
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_keyblock_init_contents(krb5_context context,
                                                krb5_enctype enctype,
                                                const void *data,
                                                size_t length,
                                                krb5_keyblock *key)
{
#if defined(HAVE_KRB5_KEYBLOCK_INIT)
        return krb5_keyblock_init(context, enctype, data, length, key);
#else
        memset(key, 0, sizeof(krb5_keyblock));
        KRB5_KEY_DATA(key) = SMB_MALLOC(length);
        if (NULL == KRB5_KEY_DATA(key)) {
                return ENOMEM;
        }
        memcpy(KRB5_KEY_DATA(key), data, length);
        KRB5_KEY_LENGTH(key) = length;
        KRB5_KEY_TYPE(key) = enctype;
        return 0;
#endif
}

/**
 * @brief Simulate a kinit by putting the tgt in the given credential cache.
 *
 * This function uses a keyblock rather than needingthe original password.
 *
 * @param[in]  ctx      The library context
 *
 * @param[in]  cc       The credential cache to put the tgt in.
 *
 * @param[in]  principal The client princial
 *
 * @param[in]  keyblock  The keyblock to use.
 *
 * @param[in]  target_service The service name of the initial credentials (or NULL).
 *
 * @param[in]  krb_options Initial credential options.
 *
 * @param[in]  expire_time    A pointer to store the experation time of the
 *                            credentials (or NULL).
 *
 * @param[in]  kdc_time       A pointer to store the time when the ticket becomes
 *                            valid (or NULL).
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_kinit_keyblock_ccache(krb5_context ctx,
                                               krb5_ccache cc,
                                               krb5_principal principal,
                                               krb5_keyblock *keyblock,
                                               const char *target_service,
                                               krb5_get_init_creds_opt *krb_options,
                                               time_t *expire_time,
                                               time_t *kdc_time)
{
        krb5_error_code code = 0;
        krb5_creds my_creds;

#if defined(HAVE_KRB5_GET_INIT_CREDS_KEYBLOCK)
        code = krb5_get_init_creds_keyblock(ctx, &my_creds, principal,
                                            keyblock, 0, target_service,
                                            krb_options);
#elif defined(HAVE_KRB5_GET_INIT_CREDS_KEYTAB)
{
#define SMB_CREDS_KEYTAB "MEMORY:tmp_smb_creds_XXXXXX"
        char tmp_name[sizeof(SMB_CREDS_KEYTAB)];
        krb5_keytab_entry entry;
        krb5_keytab keytab;
        mode_t mask;

        memset(&entry, 0, sizeof(entry));
        entry.principal = principal;
        *(KRB5_KT_KEY(&entry)) = *keyblock;

        memcpy(tmp_name, SMB_CREDS_KEYTAB, sizeof(SMB_CREDS_KEYTAB));
        mask = umask(S_IRWXO | S_IRWXG);
        mktemp(tmp_name);
        umask(mask);
        if (tmp_name[0] == 0) {
                return KRB5_KT_BADNAME;
        }
        code = krb5_kt_resolve(ctx, tmp_name, &keytab);
        if (code) {
                return code;
        }

        code = krb5_kt_add_entry(ctx, keytab, &entry);
        if (code) {
                (void)krb5_kt_close(ctx, keytab);
                goto done;
        }

        code = krb5_get_init_creds_keytab(ctx, &my_creds, principal,
                                          keytab, 0, target_service,
                                          krb_options);
        (void)krb5_kt_close(ctx, keytab);
}
#else
#error krb5_get_init_creds_keyblock not available!
#endif
        if (code) {
                return code;
        }

#ifndef SAMBA4_USES_HEIMDAL /* MIT */
        /*
         * We need to store the principal as returned from the KDC to the
         * credentials cache. If we don't do that the KRB5 library is not
         * able to find the tickets it is looking for
         */
        principal = my_creds.client;
#endif
        code = krb5_cc_initialize(ctx, cc, principal);
        if (code) {
                goto done;
        }

        code = krb5_cc_store_cred(ctx, cc, &my_creds);
        if (code) {
                goto done;
        }

        if (expire_time) {
                *expire_time = (time_t) my_creds.times.endtime;
        }

        if (kdc_time) {
                *kdc_time = (time_t) my_creds.times.starttime;
        }

        code = 0;
done:
        krb5_free_cred_contents(ctx, &my_creds);
        return code;
}

/**
 * @brief Simulate a kinit by putting the tgt in the given credential cache.
 *
 * @param[in]  ctx      The library context
 *
 * @param[in]  cc       The credential cache to put the tgt in.
 *
 * @param[in]  principal The client princial
 *
 * @param[in]  password  The password (or NULL).
 *
 * @param[in]  target_service The service name of the initial credentials (or NULL).
 *
 * @param[in]  krb_options Initial credential options.
 *
 * @param[in]  expire_time    A pointer to store the experation time of the
 *                            credentials (or NULL).
 *
 * @param[in]  kdc_time       A pointer to store the time when the ticket becomes
 *                            valid (or NULL).
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_kinit_password_ccache(krb5_context ctx,
                                               krb5_ccache cc,
                                               krb5_principal principal,
                                               const char *password,
                                               const char *target_service,
                                               krb5_get_init_creds_opt *krb_options,
                                               time_t *expire_time,
                                               time_t *kdc_time)
{
        krb5_error_code code = 0;
        krb5_creds my_creds;

        code = krb5_get_init_creds_password(ctx, &my_creds, principal,
                                            password, NULL, NULL, 0,
                                            target_service, krb_options);
        if (code) {
                return code;
        }

#ifndef SAMBA4_USES_HEIMDAL /* MIT */
        /*
         * We need to store the principal as returned from the KDC to the
         * credentials cache. If we don't do that the KRB5 library is not
         * able to find the tickets it is looking for
         */
        principal = my_creds.client;
#endif
        code = krb5_cc_initialize(ctx, cc, principal);
        if (code) {
                goto done;
        }

        code = krb5_cc_store_cred(ctx, cc, &my_creds);
        if (code) {
                goto done;
        }

        if (expire_time) {
                *expire_time = (time_t) my_creds.times.endtime;
        }

        if (kdc_time) {
                *kdc_time = (time_t) my_creds.times.starttime;
        }

        code = 0;
done:
        krb5_free_cred_contents(ctx, &my_creds);
        return code;
}

#ifdef SAMBA4_USES_HEIMDAL
/**
 * @brief Simulate a kinit by putting the tgt in the given credential cache.
 *
 * @param[in]  ctx      The library context
 *
 * @param[in]  cc       The credential cache to store the tgt in.
 *
 * @param[in]  principal The initial client princial.
 *
 * @param[in]  password  The password (or NULL).
 *
 * @param[in]  impersonate_principal The impersonatiion principal (or NULL).
 *
 * @param[in]  self_service The local service for S4U2Self if
 *                          impersonate_principal is specified).
 *
 * @param[in]  target_service The service name of the initial credentials
 *                            (kpasswd/REALM or a remote service). It defaults
 *                            to the krbtgt if NULL.
 *
 * @param[in]  krb_options Initial credential options.
 *
 * @param[in]  expire_time    A pointer to store the experation time of the
 *                            credentials (or NULL).
 *
 * @param[in]  kdc_time       A pointer to store the time when the ticket becomes
 *                            valid (or NULL).
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_kinit_s4u2_ccache(krb5_context ctx,
                                           krb5_ccache store_cc,
                                           krb5_principal init_principal,
                                           const char *init_password,
                                           krb5_principal impersonate_principal,
                                           const char *self_service,
                                           const char *target_service,
                                           krb5_get_init_creds_opt *krb_options,
                                           time_t *expire_time,
                                           time_t *kdc_time)
{
        krb5_error_code code = 0;
        krb5_get_creds_opt options;
        krb5_principal store_principal;
        krb5_creds store_creds;
        krb5_creds *s4u2self_creds;
        Ticket s4u2self_ticket;
        size_t s4u2self_ticketlen;
        krb5_creds *s4u2proxy_creds;
        krb5_principal self_princ;
        bool s4u2proxy;
        krb5_principal target_princ;
        krb5_ccache tmp_cc;
        const char *self_realm;
        krb5_principal blacklist_principal = NULL;
        krb5_principal whitelist_principal = NULL;

        code = krb5_get_init_creds_password(ctx, &store_creds,
                                            init_principal,
                                            init_password,
                                            NULL, NULL,
                                            0,
                                            NULL,
                                            krb_options);
        if (code != 0) {
                return code;
        }

        store_principal = init_principal;

        /*
         * We are trying S4U2Self now:
         *
         * As we do not want to expose our TGT in the
         * krb5_ccache, which is also holds the impersonated creds.
         *
         * Some low level krb5/gssapi function might use the TGT
         * identity and let the client act as our machine account.
         *
         * We need to avoid that and use a temporary krb5_ccache
         * in order to pass our TGT to the krb5_get_creds() function.
         */
        code = krb5_cc_new_unique(ctx, NULL, NULL, &tmp_cc);
        if (code != 0) {
                krb5_free_cred_contents(ctx, &store_creds);
                return code;
        }

        code = krb5_cc_initialize(ctx, tmp_cc, store_creds.client);
        if (code != 0) {
                krb5_cc_destroy(ctx, tmp_cc);
                krb5_free_cred_contents(ctx, &store_creds);
                return code;
        }

        code = krb5_cc_store_cred(ctx, tmp_cc, &store_creds);
        if (code != 0) {
                krb5_free_cred_contents(ctx, &store_creds);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        /*
         * we need to remember the client principal of our
         * TGT and make sure the KDC does not return this
         * in the impersonated tickets. This can happen
         * if the KDC does not support S4U2Self and S4U2Proxy.
         */
        blacklist_principal = store_creds.client;
        store_creds.client = NULL;
        krb5_free_cred_contents(ctx, &store_creds);

        /*
         * Check if we also need S4U2Proxy or if S4U2Self is
         * enough in order to get a ticket for the target.
         */
        if (target_service == NULL) {
                s4u2proxy = false;
        } else if (strcmp(target_service, self_service) == 0) {
                s4u2proxy = false;
        } else {
                s4u2proxy = true;
        }

        /*
         * For S4U2Self we need our own service principal,
         * which belongs to our own realm (available on
         * our client principal).
         */
        self_realm = krb5_principal_get_realm(ctx, init_principal);

        code = krb5_parse_name(ctx, self_service, &self_princ);
        if (code != 0) {
                krb5_free_principal(ctx, blacklist_principal);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        code = krb5_principal_set_realm(ctx, self_princ, self_realm);
        if (code != 0) {
                krb5_free_principal(ctx, blacklist_principal);
                krb5_free_principal(ctx, self_princ);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        code = krb5_get_creds_opt_alloc(ctx, &options);
        if (code != 0) {
                krb5_free_principal(ctx, blacklist_principal);
                krb5_free_principal(ctx, self_princ);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        if (s4u2proxy) {
                /*
                 * If we want S4U2Proxy, we need the forwardable flag
                 * on the S4U2Self ticket.
                 */
                krb5_get_creds_opt_set_options(ctx, options, KRB5_GC_FORWARDABLE);
        }

        code = krb5_get_creds_opt_set_impersonate(ctx, options,
                                                  impersonate_principal);
        if (code != 0) {
                krb5_get_creds_opt_free(ctx, options);
                krb5_free_principal(ctx, blacklist_principal);
                krb5_free_principal(ctx, self_princ);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        code = krb5_get_creds(ctx, options, tmp_cc,
                              self_princ, &s4u2self_creds);
        krb5_get_creds_opt_free(ctx, options);
        krb5_free_principal(ctx, self_princ);
        if (code != 0) {
                krb5_free_principal(ctx, blacklist_principal);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        if (!s4u2proxy) {
                krb5_cc_destroy(ctx, tmp_cc);

                /*
                 * Now make sure we store the impersonated principal
                 * and creds instead of the TGT related stuff
                 * in the krb5_ccache of the caller.
                 */
                code = krb5_copy_creds_contents(ctx, s4u2self_creds,
                                                &store_creds);
                krb5_free_creds(ctx, s4u2self_creds);
                if (code != 0) {
                        return code;
                }

                /*
                 * It's important to store the principal the KDC
                 * returned, as otherwise the caller would not find
                 * the S4U2Self ticket in the krb5_ccache lookup.
                 */
                store_principal = store_creds.client;
                goto store;
        }

        /*
         * We are trying S4U2Proxy:
         *
         * We need the ticket from the S4U2Self step
         * and our TGT in order to get the delegated ticket.
         */
        code = decode_Ticket((const uint8_t *)s4u2self_creds->ticket.data,
                             s4u2self_creds->ticket.length,
                             &s4u2self_ticket,
                             &s4u2self_ticketlen);
        if (code != 0) {
                krb5_free_creds(ctx, s4u2self_creds);
                krb5_free_principal(ctx, blacklist_principal);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        /*
         * we need to remember the client principal of the
         * S4U2Self stage and as it needs to match the one we
         * will get for the S4U2Proxy stage. We need this
         * in order to detect KDCs which does not support S4U2Proxy.
         */
        whitelist_principal = s4u2self_creds->client;
        s4u2self_creds->client = NULL;
        krb5_free_creds(ctx, s4u2self_creds);

        /*
         * For S4U2Proxy we also got a target service principal,
         * which also belongs to our own realm (available on
         * our client principal).
         */
        code = krb5_parse_name(ctx, target_service, &target_princ);
        if (code != 0) {
                free_Ticket(&s4u2self_ticket);
                krb5_free_principal(ctx, whitelist_principal);
                krb5_free_principal(ctx, blacklist_principal);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        code = krb5_principal_set_realm(ctx, target_princ, self_realm);
        if (code != 0) {
                free_Ticket(&s4u2self_ticket);
                krb5_free_principal(ctx, target_princ);
                krb5_free_principal(ctx, whitelist_principal);
                krb5_free_principal(ctx, blacklist_principal);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        code = krb5_get_creds_opt_alloc(ctx, &options);
        if (code != 0) {
                free_Ticket(&s4u2self_ticket);
                krb5_free_principal(ctx, target_princ);
                krb5_free_principal(ctx, whitelist_principal);
                krb5_free_principal(ctx, blacklist_principal);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        krb5_get_creds_opt_set_options(ctx, options, KRB5_GC_FORWARDABLE);
        krb5_get_creds_opt_set_options(ctx, options, KRB5_GC_CONSTRAINED_DELEGATION);

        code = krb5_get_creds_opt_set_ticket(ctx, options, &s4u2self_ticket);
        free_Ticket(&s4u2self_ticket);
        if (code != 0) {
                krb5_get_creds_opt_free(ctx, options);
                krb5_free_principal(ctx, target_princ);
                krb5_free_principal(ctx, whitelist_principal);
                krb5_free_principal(ctx, blacklist_principal);
                krb5_cc_destroy(ctx, tmp_cc);
                return code;
        }

        code = krb5_get_creds(ctx, options, tmp_cc,
                              target_princ, &s4u2proxy_creds);
        krb5_get_creds_opt_free(ctx, options);
        krb5_free_principal(ctx, target_princ);
        krb5_cc_destroy(ctx, tmp_cc);
        if (code != 0) {
                krb5_free_principal(ctx, whitelist_principal);
                krb5_free_principal(ctx, blacklist_principal);
                return code;
        }

        /*
         * Now make sure we store the impersonated principal
         * and creds instead of the TGT related stuff
         * in the krb5_ccache of the caller.
         */
        code = krb5_copy_creds_contents(ctx, s4u2proxy_creds,
                                        &store_creds);
        krb5_free_creds(ctx, s4u2proxy_creds);
        if (code != 0) {
                krb5_free_principal(ctx, whitelist_principal);
                krb5_free_principal(ctx, blacklist_principal);
                return code;
        }

        /*
         * It's important to store the principal the KDC
         * returned, as otherwise the caller would not find
         * the S4U2Self ticket in the krb5_ccache lookup.
         */
        store_principal = store_creds.client;

 store:
        if (blacklist_principal &&
            krb5_principal_compare(ctx, store_creds.client, blacklist_principal)) {
                char *sp = NULL;
                char *ip = NULL;

                code = krb5_unparse_name(ctx, blacklist_principal, &sp);
                if (code != 0) {
                        sp = NULL;
                }
                code = krb5_unparse_name(ctx, impersonate_principal, &ip);
                if (code != 0) {
                        ip = NULL;
                }
                DEBUG(1, ("smb_krb5_kinit_password_cache: "
                          "KDC returned self principal[%s] while impersonating [%s]\n",
                          sp?sp:"<no memory>",
                          ip?ip:"<no memory>"));

                SAFE_FREE(sp);
                SAFE_FREE(ip);

                krb5_free_principal(ctx, whitelist_principal);
                krb5_free_principal(ctx, blacklist_principal);
                krb5_free_cred_contents(ctx, &store_creds);
                return KRB5_FWD_BAD_PRINCIPAL;
        }
        if (blacklist_principal) {
                krb5_free_principal(ctx, blacklist_principal);
        }

        if (whitelist_principal &&
            !krb5_principal_compare(ctx, store_creds.client, whitelist_principal)) {
                char *sp = NULL;
                char *ep = NULL;

                code = krb5_unparse_name(ctx, store_creds.client, &sp);
                if (code != 0) {
                        sp = NULL;
                }
                code = krb5_unparse_name(ctx, whitelist_principal, &ep);
                if (code != 0) {
                        ep = NULL;
                }
                DEBUG(1, ("smb_krb5_kinit_password_cache: "
                          "KDC returned wrong principal[%s] we expected [%s]\n",
                          sp?sp:"<no memory>",
                          ep?ep:"<no memory>"));

                SAFE_FREE(sp);
                SAFE_FREE(ep);

                krb5_free_principal(ctx, whitelist_principal);
                krb5_free_cred_contents(ctx, &store_creds);
                return KRB5_FWD_BAD_PRINCIPAL;
        }
        if (whitelist_principal) {
                krb5_free_principal(ctx, whitelist_principal);
        }

        code = krb5_cc_initialize(ctx, store_cc, store_principal);
        if (code != 0) {
                krb5_free_cred_contents(ctx, &store_creds);
                return code;
        }

        code = krb5_cc_store_cred(ctx, store_cc, &store_creds);
        if (code != 0) {
                krb5_free_cred_contents(ctx, &store_creds);
                return code;
        }

        if (expire_time) {
                *expire_time = (time_t) store_creds.times.endtime;
        }

        if (kdc_time) {
                *kdc_time = (time_t) store_creds.times.starttime;
        }

        krb5_free_cred_contents(ctx, &store_creds);

        return 0;
}
#endif

#if !defined(HAVE_KRB5_MAKE_PRINCIPAL) && defined(HAVE_KRB5_BUILD_PRINCIPAL_ALLOC_VA)
/**
 * @brief Create a principal name using a variable argument list.
 *
 * @param[in]  context  The library context.
 *
 * @param[inout]  principal A pointer to the principal structure.
 *
 * @param[in]  _realm    The realm to use. If NULL then the function will
 *                       get the default realm name.
 *
 * @param[in]  ...       A list of 'char *' components, ending with NULL.
 *
 * Use krb5_free_principal() to free the principal when it is no longer needed.
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_make_principal(krb5_context context,
                                        krb5_principal *principal,
                                        const char *_realm, ...)
{
        krb5_error_code code;
        bool free_realm;
        char *realm;
        va_list ap;

        if (_realm) {
                realm = discard_const_p(char, _realm);
                free_realm = false;
        } else {
                code = krb5_get_default_realm(context, &realm);
                if (code) {
                        return code;
                }
                free_realm = true;
        }

        va_start(ap, _realm);
        code = krb5_build_principal_alloc_va(context, principal,
                                             strlen(realm), realm,
                                             ap);
        va_end(ap);

        if (free_realm) {
                krb5_free_default_realm(context, realm);
        }

        return code;
}
#endif

#if !defined(HAVE_KRB5_CC_GET_LIFETIME) && defined(HAVE_KRB5_CC_RETRIEVE_CRED)
/**
 * @brief Get the lifetime of the initial ticket in the cache.
 *
 * @param[in]  context  The kerberos context.
 *
 * @param[in]  id       The credential cache to get the ticket lifetime.
 *
 * @param[out] t        A pointer to a time value to store the lifetime.
 *
 * @return              0 on success, a krb5_error_code on error.
 */
krb5_error_code smb_krb5_cc_get_lifetime(krb5_context context,
                                         krb5_ccache id,
                                         time_t *t)
{
        krb5_cc_cursor cursor;
        krb5_error_code kerr;
        krb5_creds cred;
        krb5_timestamp now;

        *t = 0;

        kerr = krb5_timeofday(context, &now);
        if (kerr) {
                return kerr;
        }

        kerr = krb5_cc_start_seq_get(context, id, &cursor);
        if (kerr) {
                return kerr;
        }

        while ((kerr = krb5_cc_next_cred(context, id, &cursor, &cred)) == 0) {
#ifndef HAVE_FLAGS_IN_KRB5_CREDS
                if (cred.ticket_flags & TKT_FLG_INITIAL) {
#else
                if (cred.flags.b.initial) {
#endif
                        if (now < cred.times.endtime) {
                                *t = (time_t) (cred.times.endtime - now);
                        }
                        krb5_free_cred_contents(context, &cred);
                        break;
                }
                krb5_free_cred_contents(context, &cred);
        }

        krb5_cc_end_seq_get(context, id, &cursor);

        return kerr;
}
#endif /* HAVE_KRB5_CC_GET_LIFETIME */

#if !defined(HAVE_KRB5_FREE_CHECKSUM_CONTENTS) && defined(HAVE_FREE_CHECKSUM)
void smb_krb5_free_checksum_contents(krb5_context ctx, krb5_checksum *cksum)
{
        free_Checksum(cksum);
}
#endif

/**
 * @brief Compute a checksum operating on a keyblock.
 *
 * This function computes a checksum over a PAC using the keyblock for a keyed
 * checksum.
 *
 * @param[in]  mem_ctx A talloc context to alocate the signature on.
 *
 * @param[in]  pac_data The PAC as input.
 *
 * @param[in]  context  The library context.
 *
 * @param[in]  keyblock Encryption key for a keyed checksum.
 *
 * @param[out] sig_type The checksum type
 *
 * @param[out] sig_blob The talloc'ed checksum
 *
 * The caller must free the sig_blob with talloc_free() when it is not needed
 * anymore.
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_make_pac_checksum(TALLOC_CTX *mem_ctx,
                                           DATA_BLOB *pac_data,
                                           krb5_context context,
                                           const krb5_keyblock *keyblock,
                                           uint32_t *sig_type,
                                           DATA_BLOB *sig_blob)
{
        krb5_error_code ret;
        krb5_checksum cksum;
#if defined(HAVE_KRB5_CRYPTO_INIT) && defined(HAVE_KRB5_CREATE_CHECKSUM)
        krb5_crypto crypto;


        ret = krb5_crypto_init(context,
                               keyblock,
                               0,
                               &crypto);
        if (ret) {
                DEBUG(0,("krb5_crypto_init() failed: %s\n",
                          smb_get_krb5_error_message(context, ret, mem_ctx)));
                return ret;
        }
        ret = krb5_create_checksum(context,
                                   crypto,
                                   KRB5_KU_OTHER_CKSUM,
                                   0,
                                   pac_data->data,
                                   pac_data->length,
                                   &cksum);
        if (ret) {
                DEBUG(2, ("PAC Verification failed: %s\n",
                          smb_get_krb5_error_message(context, ret, mem_ctx)));
        }

        krb5_crypto_destroy(context, crypto);

        if (ret) {
                return ret;
        }

        *sig_type = cksum.cksumtype;
        *sig_blob = data_blob_talloc(mem_ctx,
                                        cksum.checksum.data,
                                        cksum.checksum.length);
#elif defined(HAVE_KRB5_C_MAKE_CHECKSUM)
        krb5_data input;

        input.data = (char *)pac_data->data;
        input.length = pac_data->length;

        ret = krb5_c_make_checksum(context,
                                   0,
                                   keyblock,
                                   KRB5_KEYUSAGE_APP_DATA_CKSUM,
                                   &input,
                                   &cksum);
        if (ret) {
                DEBUG(2, ("PAC Verification failed: %s\n",
                          smb_get_krb5_error_message(context, ret, mem_ctx)));
                return ret;
        }

        *sig_type = cksum.checksum_type;
        *sig_blob = data_blob_talloc(mem_ctx,
                                        cksum.contents,
                                        cksum.length);

#else
#error krb5_create_checksum or krb5_c_make_checksum not available
#endif /* HAVE_KRB5_C_MAKE_CHECKSUM */
        smb_krb5_free_checksum_contents(context, &cksum);

        return 0;
}


/**
 * @brief Get realm of a principal
 *
 * @param[in] context   The library context
 *
 * @param[in] principal The principal to get the realm from.
 *
 * @return An allocated string with the realm or NULL if an error occured.
 *
 * The caller must free the realm string with free() if not needed anymore.
 */
char *smb_krb5_principal_get_realm(krb5_context context,
                                   krb5_const_principal principal)
{
#ifdef HAVE_KRB5_PRINCIPAL_GET_REALM /* Heimdal */
        return strdup(discard_const_p(char, krb5_principal_get_realm(context, principal)));
#elif defined(krb5_princ_realm) /* MIT */
        krb5_data *realm;
        realm = discard_const_p(krb5_data,
                                krb5_princ_realm(context, principal));
        return strndup(realm->data, realm->length);
#else
#error UNKNOWN_GET_PRINC_REALM_FUNCTIONS
#endif
}

/**
 * @brief Get realm of a principal
 *
 * @param[in] context   The library context
 *
 * @param[in] principal The principal to set the realm
 *
 * @param[in] realm     The realm as a string to set.
 *
 * @retur 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_principal_set_realm(krb5_context context,
                                             krb5_principal principal,
                                             const char *realm)
{
#ifdef HAVE_KRB5_PRINCIPAL_SET_REALM /* Heimdal */
        return krb5_principal_set_realm(context, principal, realm);
#elif defined(krb5_princ_realm) && defined(krb5_princ_set_realm) /* MIT */
        krb5_error_code ret;
        krb5_data data;
        krb5_data *old_data;

        old_data = krb5_princ_realm(context, principal);

        ret = smb_krb5_copy_data_contents(&data,
                                          realm,
                                          strlen(realm));
        if (ret) {
                return ret;
        }

        /* free realm before setting */
        free(old_data->data);

        krb5_princ_set_realm(context, principal, &data);

        return ret;
#else
#error UNKNOWN_PRINC_SET_REALM_FUNCTION
#endif
}


/************************************************************************
 Routine to get the default realm from the kerberos credentials cache.
 Caller must free if the return value is not NULL.
************************************************************************/

static char *smb_krb5_get_default_realm_from_ccache(TALLOC_CTX *mem_ctx)
{
        char *realm = NULL;
        krb5_context ctx = NULL;
        krb5_ccache cc = NULL;
        krb5_principal princ = NULL;

        initialize_krb5_error_table();
        if (krb5_init_context(&ctx)) {
                return NULL;
        }

        DEBUG(5,("kerberos_get_default_realm_from_ccache: "
                "Trying to read krb5 cache: %s\n",
                krb5_cc_default_name(ctx)));
        if (krb5_cc_default(ctx, &cc)) {
                DEBUG(5,("kerberos_get_default_realm_from_ccache: "
                        "failed to read default cache\n"));
                goto out;
        }
        if (krb5_cc_get_principal(ctx, cc, &princ)) {
                DEBUG(5,("kerberos_get_default_realm_from_ccache: "
                        "failed to get default principal\n"));
                goto out;
        }

#if defined(HAVE_KRB5_PRINCIPAL_GET_REALM)
        realm = talloc_strdup(mem_ctx, krb5_principal_get_realm(ctx, princ));
#elif defined(HAVE_KRB5_PRINC_REALM)
        {
                krb5_data *realm_data = krb5_princ_realm(ctx, princ);
                realm = talloc_strndup(mem_ctx, realm_data->data, realm_data->length);
        }
#endif

  out:

        if (ctx) {
                if (princ) {
                        krb5_free_principal(ctx, princ);
                }
                if (cc) {
                        krb5_cc_close(ctx, cc);
                }
                krb5_free_context(ctx);
        }

        return realm;
}

/************************************************************************
 Routine to get the realm from a given DNS name.
************************************************************************/

static char *smb_krb5_get_realm_from_hostname(TALLOC_CTX *mem_ctx,
                                                const char *hostname)
{
#if defined(HAVE_KRB5_REALM_TYPE)
        /* Heimdal. */
        krb5_realm *realm_list = NULL;
#else
        /* MIT */
        char **realm_list = NULL;
#endif
        char *realm = NULL;
        krb5_error_code kerr;
        krb5_context ctx = NULL;

        initialize_krb5_error_table();
        if (krb5_init_context(&ctx)) {
                return NULL;
        }

        kerr = krb5_get_host_realm(ctx, hostname, &realm_list);
        if (kerr != 0) {
                DEBUG(3,("kerberos_get_realm_from_hostname %s: "
                        "failed %s\n",
                        hostname ? hostname : "(NULL)",
                        error_message(kerr) ));
                goto out;
        }

        if (realm_list && realm_list[0]) {
                realm = talloc_strdup(mem_ctx, realm_list[0]);
        }

  out:

        if (ctx) {
                if (realm_list) {
                        krb5_free_host_realm(ctx, realm_list);
                        realm_list = NULL;
                }
                krb5_free_context(ctx);
                ctx = NULL;
        }
        return realm;
}

/**
 * @brief Get the principal as a string from the service hostname.
 *
 * @param[in]  mem_ctx  The talloc context
 *
 * @param[in]  service  The service name
 *
 * @param[in]  remote_name The remote name
 *
 * @param[in]  default_realm The default_realm if we cannot get it from the
 *                           hostname or netbios name.
 *
 * @return A talloc'ed principal string or NULL if an error occured.
 *
 * The caller needs to free the principal with talloc_free() if it isn't needed
 * anymore.
 */
char *smb_krb5_get_principal_from_service_hostname(TALLOC_CTX *mem_ctx,
                                                   const char *service,
                                                   const char *remote_name,
                                                   const char *default_realm)
{
        char *realm = NULL;
        char *host = NULL;
        char *principal;
        host = strchr_m(remote_name, '.');
        if (host) {
                /* DNS name. */
                realm = smb_krb5_get_realm_from_hostname(talloc_tos(),
                                                         remote_name);
        } else {
                /* NetBIOS name - use our realm. */
                realm = smb_krb5_get_default_realm_from_ccache(talloc_tos());
        }

        if (realm == NULL || *realm == '\0') {
                realm = talloc_strdup(talloc_tos(), default_realm);
                if (!realm) {
                        return NULL;
                }
                DEBUG(3,("Cannot get realm from, "
                         "desthost %s or default ccache. Using default "
                         "smb.conf realm %s\n",
                         remote_name,
                         realm));
        }

        principal = talloc_asprintf(mem_ctx,
                                    "%s/%s@%s",
                                    service, remote_name,
                                    realm);
        TALLOC_FREE(realm);
        return principal;
}

/**
 * @brief Get an error string from a Kerberos error code.
 *
 * @param[in]  context  The library context.
 *
 * @param[in]  code     The Kerberos error code.
 *
 * @param[in]  mem_ctx  The talloc context to allocate the error string on.
 *
 * @return A talloc'ed error string or NULL if an error occured.
 *
 * The caller must free the returned error string with talloc_free() if not
 * needed anymore
 */
char *smb_get_krb5_error_message(krb5_context context,
                                 krb5_error_code code,
                                 TALLOC_CTX *mem_ctx)
{
        char *ret;

#if defined(HAVE_KRB5_GET_ERROR_MESSAGE) && defined(HAVE_KRB5_FREE_ERROR_MESSAGE)
        const char *context_error = krb5_get_error_message(context, code);
        if (context_error) {
                ret = talloc_asprintf(mem_ctx, "%s: %s",
                                        error_message(code), context_error);
                krb5_free_error_message(context, context_error);
                return ret;
        }
#endif
        ret = talloc_strdup(mem_ctx, error_message(code));
        return ret;
}


/**
 * @brief Return the kerberos library setting for: libdefaults:allow_weak_crypto
 *
 * @param[in]  context  The library context
 *
 * @return True if weak crypto is allowed, false if not.
 */
krb5_boolean smb_krb5_get_allowed_weak_crypto(krb5_context context)
#if defined(HAVE_KRB5_CONFIG_GET_BOOL_DEFAULT)
{
        return krb5_config_get_bool_default(context,
                                            NULL,
                                            FALSE,
                                            "libdefaults",
                                            "allow_weak_crypto",
                                            NULL);
}
#elif defined(HAVE_PROFILE_H) && defined(HAVE_KRB5_GET_PROFILE)
{
#include <profile.h>
        krb5_error_code ret;
        krb5_boolean ret_default = false;
        profile_t profile;
        int ret_profile;

        ret = krb5_get_profile(context,
                               &profile);
        if (ret) {
                return ret_default;
        }

        ret = profile_get_boolean(profile,
                                  "libdefaults",
                                  "allow_weak_crypto",
                                  NULL, /* subsubname */
                                  ret_default, /* def_val */
                                  &ret_profile /* *ret_default */);
        if (ret) {
                return ret_default;
        }

        profile_release(profile);

        return ret_profile;
}
#else
#error UNKNOWN_KRB5_CONFIG_ROUTINES
#endif

/**
 * @brief Return the type of a krb5_principal
 *
 * @param[in]  context  The library context.
 *
 * @param[in]  principal The principal to get the type from.
 *
 * @return The integer type of the principal.
 */
int smb_krb5_principal_get_type(krb5_context context,
                                krb5_const_principal principal)
{
#ifdef HAVE_KRB5_PRINCIPAL_GET_TYPE /* Heimdal */
        return krb5_principal_get_type(context, principal);
#elif defined(krb5_princ_type) /* MIT */
        return krb5_princ_type(context, principal);
#else
#error  UNKNOWN_PRINC_GET_TYPE_FUNCTION
#endif
}

/**
 * @brief Set the type of a principal
 *
 * @param[in]  context  The library context
 *
 * @param[inout] principal The principal to set the type for.
 *
 * @param[in]  type     The principal type to set.
 */
void smb_krb5_principal_set_type(krb5_context context,
                                 krb5_principal principal,
                                 int type)
{
#ifdef HAVE_KRB5_PRINCIPAL_SET_TYPE /* Heimdal */
        krb5_principal_set_type(context, principal, type);
#elif defined(krb5_princ_type) /* MIT */
        krb5_princ_type(context, principal) = type;
#else
#error  UNKNOWN_PRINC_SET_TYPE_FUNCTION
#endif
}

#if !defined(HAVE_KRB5_WARNX)
/**
 * @brief Log a Kerberos message
 *
 * It sends the message to com_err.
 *
 * @param[in]  context  The library context
 *
 * @param[in]  fmt      The message format
 *
 * @param[in]  ...      The message arguments
 *
 * @return 0 on success.
 */
krb5_error_code krb5_warnx(krb5_context context, const char *fmt, ...)
{
        va_list args;

        va_start(args, fmt);
        com_err_va("samba-kdc", errno, fmt, args);
        va_end(args);

        return 0;
}
#endif

/**
 * @brief Copy a credential cache.
 *
 * @param[in]  context  The library context.
 *
 * @param[in]  incc     Credential cache to be copied.
 *
 * @param[inout] outcc  Copy of credential cache to be filled in.
 *
 * @return 0 on success, a Kerberos error code otherwise.
 */
krb5_error_code smb_krb5_cc_copy_creds(krb5_context context,
                                       krb5_ccache incc, krb5_ccache outcc)
{
#ifdef HAVE_KRB5_CC_COPY_CACHE /* Heimdal */
        return krb5_cc_copy_cache(context, incc, outcc);
#elif defined(HAVE_KRB5_CC_COPY_CREDS)
        krb5_error_code ret;
        krb5_principal princ = NULL;

        ret = krb5_cc_get_principal(context, incc, &princ);
        if (ret != 0) {
                return ret;
        }
        ret = krb5_cc_initialize(context, outcc, princ);
        krb5_free_principal(context, princ);
        if (ret != 0) {
                return ret;
        }
        return krb5_cc_copy_creds(context, incc, outcc);
#else
#error UNKNOWN_KRB5_CC_COPY_CACHE_OR_CREDS_FUNCTION
#endif
}

/**********************************************************
 * ADS KRB5 CALLS
 **********************************************************/

static bool ads_cleanup_expired_creds(krb5_context context,
                                      krb5_ccache  ccache,
                                      krb5_creds  *credsp)
{
        krb5_error_code retval;
        const char *cc_type = krb5_cc_get_type(context, ccache);

        DEBUG(3, ("ads_cleanup_expired_creds: Ticket in ccache[%s:%s] expiration %s\n",
                  cc_type, krb5_cc_get_name(context, ccache),
                  http_timestring(talloc_tos(), credsp->times.endtime)));

        /* we will probably need new tickets if the current ones
           will expire within 10 seconds.
        */
        if (credsp->times.endtime >= (time(NULL) + 10))
                return false;

        /* heimdal won't remove creds from a file ccache, and
           perhaps we shouldn't anyway, since internally we
           use memory ccaches, and a FILE one probably means that
           we're using creds obtained outside of our exectuable
        */
        if (strequal(cc_type, "FILE")) {
                DEBUG(5, ("ads_cleanup_expired_creds: We do not remove creds from a %s ccache\n", cc_type));
                return false;
        }

        retval = krb5_cc_remove_cred(context, ccache, 0, credsp);
        if (retval) {
                DEBUG(1, ("ads_cleanup_expired_creds: krb5_cc_remove_cred failed, err %s\n",
                          error_message(retval)));
                /* If we have an error in this, we want to display it,
                   but continue as though we deleted it */
        }
        return true;
}

/* Allocate and setup the auth context into the state we need. */

static krb5_error_code ads_setup_auth_context(krb5_context context,
                                              krb5_auth_context *auth_context)
{
        krb5_error_code retval;

        retval = krb5_auth_con_init(context, auth_context );
        if (retval) {
                DEBUG(1,("krb5_auth_con_init failed (%s)\n",
                        error_message(retval)));
                return retval;
        }

        /* Ensure this is an addressless ticket. */
        retval = krb5_auth_con_setaddrs(context, *auth_context, NULL, NULL);
        if (retval) {
                DEBUG(1,("krb5_auth_con_setaddrs failed (%s)\n",
                        error_message(retval)));
        }

        return retval;
}

#if defined(TKT_FLG_OK_AS_DELEGATE ) && defined(HAVE_KRB5_AUTH_CON_SETUSERUSERKEY) && defined(KRB5_AUTH_CONTEXT_USE_SUBKEY) && defined(HAVE_KRB5_AUTH_CON_SET_REQ_CKSUMTYPE)
static krb5_error_code ads_create_gss_checksum(krb5_data *in_data, /* [inout] */
                                               uint32_t gss_flags)
{
        unsigned int orig_length = in_data->length;
        unsigned int base_cksum_size = GSSAPI_CHECKSUM_SIZE;
        char *gss_cksum = NULL;

        if (orig_length) {
                /* Extra length field for delgated ticket. */
                base_cksum_size += 4;
        }

        if ((unsigned int)base_cksum_size + orig_length <
                        (unsigned int)base_cksum_size) {
                return EINVAL;
        }

        gss_cksum = (char *)SMB_MALLOC(base_cksum_size + orig_length);
        if (gss_cksum == NULL) {
                return ENOMEM;
        }

        memset(gss_cksum, '\0', base_cksum_size + orig_length);
        SIVAL(gss_cksum, 0, GSSAPI_BNDLENGTH);

        /*
         * GSS_C_NO_CHANNEL_BINDINGS means 16 zero bytes.
         * This matches the behavior of heimdal and mit.
         *
         * And it is needed to work against some closed source
         * SMB servers.
         *
         * See bug #7883
         */
        memset(&gss_cksum[4], 0x00, GSSAPI_BNDLENGTH);

        SIVAL(gss_cksum, 20, gss_flags);

        if (orig_length) {
                SSVAL(gss_cksum, 24, 1); /* The Delegation Option identifier */
                SSVAL(gss_cksum, 26, orig_length);
                /* Copy the kerberos KRB_CRED data */
                memcpy(gss_cksum + 28, in_data->data, orig_length);
                free(in_data->data);
                in_data->data = NULL;
                in_data->length = 0;
        }
        in_data->data = gss_cksum;
        in_data->length = base_cksum_size + orig_length;
        return 0;
}
#endif

/*
 * We can't use krb5_mk_req because w2k wants the service to be in a particular
 * format.
 */
static krb5_error_code ads_krb5_mk_req(krb5_context context,
                                       krb5_auth_context *auth_context,
                                       const krb5_flags ap_req_options,
                                       const char *principal,
                                       krb5_ccache ccache,
                                       krb5_data *outbuf,
                                       time_t *expire_time,
                                       const char *impersonate_princ_s)
{
        krb5_error_code retval;
        krb5_principal server;
        krb5_principal impersonate_princ = NULL;
        krb5_creds *credsp;
        krb5_creds creds;
        krb5_data in_data;
        bool creds_ready = false;
        int i = 0, maxtries = 3;
        bool ok;

        ZERO_STRUCT(in_data);

        retval = smb_krb5_parse_name(context, principal, &server);
        if (retval != 0) {
                DEBUG(1,("ads_krb5_mk_req: Failed to parse principal %s\n", principal));
                return retval;
        }

        if (impersonate_princ_s) {
                retval = smb_krb5_parse_name(context, impersonate_princ_s,
                                             &impersonate_princ);
                if (retval) {
                        DEBUG(1,("ads_krb5_mk_req: Failed to parse principal %s\n", impersonate_princ_s));
                        goto cleanup_princ;
                }
        }

        /* obtain ticket & session key */
        ZERO_STRUCT(creds);
        if ((retval = krb5_copy_principal(context, server, &creds.server))) {
                DEBUG(1,("ads_krb5_mk_req: krb5_copy_principal failed (%s)\n",
                         error_message(retval)));
                goto cleanup_princ;
        }

        retval = krb5_cc_get_principal(context, ccache, &creds.client);
        if (retval != 0) {
                /* This can commonly fail on smbd startup with no ticket in the cache.
                 * Report at higher level than 1. */
                DEBUG(3,("ads_krb5_mk_req: krb5_cc_get_principal failed (%s)\n",
                         error_message(retval)));
                goto cleanup_creds;
        }

        while (!creds_ready && (i < maxtries)) {

                retval = smb_krb5_get_credentials(context,
                                                  ccache,
                                                  creds.client,
                                                  creds.server,
                                                  impersonate_princ,
                                                  &credsp);
                if (retval != 0) {
                        DBG_WARNING("smb_krb5_get_credentials failed for %s "
                                    "(%s)\n",
                                    principal,
                                    error_message(retval));
                        goto cleanup_creds;
                }

                /* cope with ticket being in the future due to clock skew */
                if ((unsigned)credsp->times.starttime > time(NULL)) {
                        time_t t = time(NULL);
                        int time_offset =(int)((unsigned)credsp->times.starttime-t);
                        DEBUG(4,("ads_krb5_mk_req: Advancing clock by %d seconds to cope with clock skew\n", time_offset));
                        krb5_set_real_time(context, t + time_offset + 1, 0);
                }

                ok = ads_cleanup_expired_creds(context, ccache, credsp);
                if (!ok) {
                        creds_ready = true;
                }

                i++;
        }

        DBG_DEBUG("Ticket (%s) in ccache (%s:%s) is valid until: (%s - %u)\n",
                  principal,
                  krb5_cc_get_type(context, ccache),
                  krb5_cc_get_name(context, ccache),
                  http_timestring(talloc_tos(),
                                  (unsigned)credsp->times.endtime),
                  (unsigned)credsp->times.endtime);

        if (expire_time) {
                *expire_time = (time_t)credsp->times.endtime;
        }

        /* Allocate the auth_context. */
        retval = ads_setup_auth_context(context, auth_context);
        if (retval != 0) {
                DBG_WARNING("ads_setup_auth_context failed (%s)\n",
                            error_message(retval));
                goto cleanup_creds;
        }

#if defined(TKT_FLG_OK_AS_DELEGATE ) && defined(HAVE_KRB5_AUTH_CON_SETUSERUSERKEY) && defined(KRB5_AUTH_CONTEXT_USE_SUBKEY) && defined(HAVE_KRB5_AUTH_CON_SET_REQ_CKSUMTYPE)
        {
                uint32_t gss_flags = 0;

                if (credsp->ticket_flags & TKT_FLG_OK_AS_DELEGATE) {
                        /*
                         * Fetch a forwarded TGT from the KDC so that we can
                         * hand off a 2nd ticket as part of the kerberos
                         * exchange.
                         */

                        DBG_INFO("Server marked as OK to delegate to, building "
                                 "forwardable TGT\n");

                        retval = krb5_auth_con_setuseruserkey(context,
                                        *auth_context,
                                        &credsp->keyblock );
                        if (retval != 0) {
                                DBG_WARNING("krb5_auth_con_setuseruserkey "
                                            "failed (%s)\n",
                                            error_message(retval));
                                goto cleanup_creds;
                        }

                        /* Must use a subkey for forwarded tickets. */
                        retval = krb5_auth_con_setflags(context,
                                                        *auth_context,
                                                        KRB5_AUTH_CONTEXT_USE_SUBKEY);
                        if (retval != 0) {
                                DBG_WARNING("krb5_auth_con_setflags failed (%s)\n",
                                            error_message(retval));
                                goto cleanup_creds;
                        }

                        retval = krb5_fwd_tgt_creds(context,/* Krb5 context [in] */
                                *auth_context,  /* Authentication context [in] */
                                discard_const_p(char, KRB5_TGS_NAME),  /* Ticket service name ("krbtgt") [in] */
                                credsp->client, /* Client principal for the tgt [in] */
                                credsp->server, /* Server principal for the tgt [in] */
                                ccache,         /* Credential cache to use for storage [in] */
                                1,              /* Turn on for "Forwardable ticket" [in] */
                                &in_data );     /* Resulting response [out] */

                        if (retval) {
                                DBG_INFO("krb5_fwd_tgt_creds failed (%s)\n",
                                         error_message(retval));

                                /*
                                 * This is not fatal. Delete the *auth_context and continue
                                 * with krb5_mk_req_extended to get a non-forwardable ticket.
                                 */

                                if (in_data.data) {
                                        free( in_data.data );
                                        in_data.data = NULL;
                                        in_data.length = 0;
                                }
                                krb5_auth_con_free(context, *auth_context);
                                *auth_context = NULL;
                                retval = ads_setup_auth_context(context, auth_context);
                                if (retval != 0) {
                                        DBG_WARNING("ads_setup_auth_context failed (%s)\n",
                                                    error_message(retval));
                                        goto cleanup_creds;
                                }
                        } else {
                                /* We got a delegated ticket. */
                                gss_flags |= GSS_C_DELEG_FLAG;
                        }
                }

                /* Frees and reallocates in_data into a GSS checksum blob. */
                retval = ads_create_gss_checksum(&in_data, gss_flags);
                if (retval != 0) {
                        goto cleanup_data;
                }

                /* We always want GSS-checksum types. */
                retval = krb5_auth_con_set_req_cksumtype(context, *auth_context, GSSAPI_CHECKSUM );
                if (retval != 0) {
                        DEBUG(1,("krb5_auth_con_set_req_cksumtype failed (%s)\n",
                                error_message(retval)));
                        goto cleanup_data;
                }
        }
#endif

        retval = krb5_mk_req_extended(context, auth_context, ap_req_options,
                                      &in_data, credsp, outbuf);
        if (retval != 0) {
                DBG_WARNING("krb5_mk_req_extended failed (%s)\n",
                            error_message(retval));
        }

#if defined(TKT_FLG_OK_AS_DELEGATE ) && defined(HAVE_KRB5_AUTH_CON_SETUSERUSERKEY) && defined(KRB5_AUTH_CONTEXT_USE_SUBKEY) && defined(HAVE_KRB5_AUTH_CON_SET_REQ_CKSUMTYPE)
cleanup_data:
#endif

        if (in_data.data) {
                free( in_data.data );
                in_data.length = 0;
        }

        krb5_free_creds(context, credsp);

cleanup_creds:
        krb5_free_cred_contents(context, &creds);

cleanup_princ:
        krb5_free_principal(context, server);
        if (impersonate_princ) {
                krb5_free_principal(context, impersonate_princ);
        }

        return retval;
}

/*
  get a kerberos5 ticket for the given service
*/
int ads_krb5_cli_get_ticket(TALLOC_CTX *mem_ctx,
                            const char *principal,
                            time_t time_offset,
                            DATA_BLOB *ticket,
                            DATA_BLOB *session_key_krb5,
                            uint32_t extra_ap_opts, const char *ccname,
                            time_t *tgs_expire,
                            const char *impersonate_princ_s)
{
        krb5_error_code retval;
        krb5_data packet;
        krb5_context context = NULL;
        krb5_ccache ccdef = NULL;
        krb5_auth_context auth_context = NULL;
        krb5_enctype enc_types[] = {
#ifdef HAVE_ENCTYPE_AES256_CTS_HMAC_SHA1_96
                ENCTYPE_AES256_CTS_HMAC_SHA1_96,
#endif
#ifdef HAVE_ENCTYPE_AES128_CTS_HMAC_SHA1_96
                ENCTYPE_AES128_CTS_HMAC_SHA1_96,
#endif
                ENCTYPE_ARCFOUR_HMAC,
                ENCTYPE_DES_CBC_MD5,
                ENCTYPE_DES_CBC_CRC,
                ENCTYPE_NULL};
        bool ok;

        initialize_krb5_error_table();
        retval = krb5_init_context(&context);
        if (retval != 0) {
                DBG_WARNING("krb5_init_context failed (%s)\n",
                            error_message(retval));
                goto failed;
        }

        if (time_offset != 0) {
                krb5_set_real_time(context, time(NULL) + time_offset, 0);
        }

        retval = krb5_cc_resolve(context,
                                 ccname ? ccname : krb5_cc_default_name(context),
                                 &ccdef);
        if (retval != 0) {
                DBG_WARNING("krb5_cc_default failed (%s)\n",
                            error_message(retval));
                goto failed;
        }

        retval = krb5_set_default_tgs_ktypes(context, enc_types);
        if (retval != 0) {
                DBG_WARNING("krb5_set_default_tgs_ktypes failed (%s)\n",
                            error_message(retval));
                goto failed;
        }

        retval = ads_krb5_mk_req(context,
                                 &auth_context,
                                 AP_OPTS_USE_SUBKEY | (krb5_flags)extra_ap_opts,
                                 principal,
                                 ccdef,
                                 &packet,
                                 tgs_expire,
                                 impersonate_princ_s);
        if (retval != 0) {
                goto failed;
        }

        ok = smb_krb5_get_smb_session_key(mem_ctx,
                                          context,
                                          auth_context,
                                          session_key_krb5,
                                          false);
        if (!ok) {
                retval = ENOMEM;
                goto failed;
        }

        *ticket = data_blob_talloc(mem_ctx, packet.data, packet.length);

        smb_krb5_free_data_contents(context, &packet);

failed:

        if (context) {
                if (ccdef) {
                        krb5_cc_close(context, ccdef);
                }
                if (auth_context) {
                        krb5_auth_con_free(context, auth_context);
                }
                krb5_free_context(context);
        }

        return retval;
}

#else /* HAVE_KRB5 */
/* This saves a few linking headaches */
int ads_krb5_cli_get_ticket(TALLOC_CTX *mem_ctx,
                            const char *principal,
                            time_t time_offset,
                            DATA_BLOB *ticket,
                            DATA_BLOB *session_key_krb5,
                            uint32_t extra_ap_opts, const char *ccname,
                            time_t *tgs_expire,
                            const char *impersonate_princ_s)
{
         DEBUG(0,("NO KERBEROS SUPPORT\n"));
         return 1;
}

#endif /* HAVE_KRB5 */