/src/samba/lib/krb5_wrap/krb5_samba.c

Source
/*
   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"
#include "lib/crypto/md4.h"
#include "../libds/common/flags.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_FREE_ENCTYPES)
void krb5_free_enctypes(krb5_context context, krb5_enctype *val) {
  krb5_xfree(val);
}
#endif

#if !defined(HAVE_KRB5_FREE_STRING)
void krb5_free_string(krb5_context context, char *val) {
  SAFE_FREE(val);
}
#endif

krb5_error_code smb_krb5_princ_component(krb5_context context,
           krb5_const_principal principal,
           int i,
           krb5_data *data);
krb5_error_code smb_krb5_princ_component(krb5_context context,
           krb5_const_principal principal,
           int i,
           krb5_data *data)
{
#if defined(HAVE_KRB5_PRINCIPAL_GET_COMP_STRING) && !defined(HAVE_KRB5_PRINC_COMPONENT)
  const char *component = NULL;

  if (i < 0) {
    return EINVAL;
  }

  component = krb5_principal_get_comp_string(context, principal, i);
  if (component == NULL) {
    return ENOENT;
  }

  *data = smb_krb5_make_data(discard_const_p(char, component), strlen(component));

  return 0;
#else
  const krb5_data *kdata = NULL;

  if (i < 0) {
    return EINVAL;
  }

  kdata = krb5_princ_component(context, principal, i);
  if (kdata == NULL) {
    return ENOENT;
  }

  *data = *kdata;

  return 0;
#endif
}

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

/**
 * @brief Stores the address of a 'struct sockaddr_storage' into 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 the address in.
 *
 * @return True on success, false if an error occurred.
 */
bool smb_krb5_sockaddr_to_kaddr(struct sockaddr_storage *paddr,
        krb5_address *pkaddr)
{
  memset(pkaddr, '\0', sizeof(krb5_address));
#if defined(HAVE_ADDR_TYPE_IN_KRB5_ADDRESS)
/* HEIMDAL */
#ifdef HAVE_IPV6
  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;
  }
#elif defined(HAVE_ADDRTYPE_IN_KRB5_ADDRESS)
/* MIT */
#ifdef HAVE_IPV6
  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;
  }
#else
#error UNKNOWN_ADDRTYPE
#endif
  return false;
}

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 - ERROR_TABLE_BASE_krb5;

  errpkt.text.length = 0;
  if (e_text != NULL) {
    errpkt.text = smb_krb5_make_data(discard_const_p(char, e_text), strlen(e_text));
  }

  errpkt.e_data = smb_krb5_make_data(NULL, 0);
  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,
            const krb5_data *salt,
            const krb5_data *password,
            krb5_enctype enctype,
            krb5_keyblock *key)
{
  int ret = 0;

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

  if ((int)enctype == (int)ENCTYPE_ARCFOUR_HMAC) {
    TALLOC_CTX *frame = talloc_stackframe();
    uint8_t *utf16 = NULL;
    size_t utf16_size = 0;
    uint8_t nt_hash[16];
    bool ok;

    ok = convert_string_talloc(frame, CH_UNIX, CH_UTF16LE,
             password->data, password->length,
             &utf16, &utf16_size);
    if (!ok) {
      if (errno == 0) {
        errno = EINVAL;
      }
      ret = errno;
      TALLOC_FREE(frame);
      return ret;
    }

    mdfour(nt_hash, utf16, utf16_size);
    BURN_PTR_SIZE(utf16, utf16_size);
    ret = smb_krb5_keyblock_init_contents(context,
                  ENCTYPE_ARCFOUR_HMAC,
                  nt_hash,
                  sizeof(nt_hash),
                  key);
    ZERO_STRUCT(nt_hash);
    if (ret != 0) {
      TALLOC_FREE(frame);
      return ret;
    }

    TALLOC_FREE(frame);
    return 0;
  }

#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 = salt.saltvalue;

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

/**
 * @brief This constructs the salt principal used by active directory
 *
 * Most Kerberos encryption types require a salt in order to
 * calculate the long term private key for user/computer object
 * based on a password.
 *
 * The returned _salt_principal is a string in forms like this:
 * - host/somehost.example.com@EXAMPLE.COM
 * - SomeAccount@EXAMPLE.COM
 * - SomePrincipal@EXAMPLE.COM
 *
 * This is not the form that's used as salt, it's just
 * the human readable form. It needs to be converted by
 * smb_krb5_salt_principal2data().
 *
 * @param[in]  realm              The realm the user/computer is added too.
 *
 * @param[in]  sAMAccountName     The sAMAccountName attribute of the object.
 *
 * @param[in]  userPrincipalName  The userPrincipalName attribute of the object
 *                                or NULL if not available.
 *
 * @param[in]  uac_flags          UF_ACCOUNT_TYPE_MASKed userAccountControl field
 *
 * @param[in]  mem_ctx            The TALLOC_CTX to allocate _salt_principal.
 *
 * @param[out]  _salt_principal   The resulting principal as string.
 *
 * @retval 0 Success; otherwise - Kerberos error codes
 *
 * @see smb_krb5_salt_principal2data
 */
int smb_krb5_salt_principal(krb5_context krb5_ctx,
          const char *realm,
          const char *sAMAccountName,
          const char *userPrincipalName,
          uint32_t uac_flags,
          krb5_principal *salt_princ)
{
  TALLOC_CTX *frame = talloc_stackframe();
  char *upper_realm = NULL;
  const char *principal = NULL;
  int principal_len = 0;
  krb5_error_code krb5_ret;

  *salt_princ = NULL;

  if (sAMAccountName == NULL) {
    TALLOC_FREE(frame);
    return EINVAL;
  }

  if (realm == NULL) {
    TALLOC_FREE(frame);
    return EINVAL;
  }

  if (uac_flags & ~UF_ACCOUNT_TYPE_MASK) {
    /*
     * catch callers which still
     * pass 'true'.
     */
    TALLOC_FREE(frame);
    return EINVAL;
  }
  if (uac_flags == 0) {
    /*
     * catch callers which still
     * pass 'false'.
     */
    TALLOC_FREE(frame);
    return EINVAL;
  }

  upper_realm = strupper_talloc(frame, realm);
  if (upper_realm == NULL) {
    TALLOC_FREE(frame);
    return ENOMEM;
  }

  /* Many, many thanks to lukeh@padl.com for this
   * algorithm, described in his Nov 10 2004 mail to
   * samba-technical@lists.samba.org */

  /*
   * Determine a salting principal
   */
  if (uac_flags & UF_TRUST_ACCOUNT_MASK) {
    int computer_len = 0;

    computer_len = strlen(sAMAccountName);
    if (sAMAccountName[computer_len-1] == '$') {
      computer_len -= 1;
    }

    if (uac_flags & UF_INTERDOMAIN_TRUST_ACCOUNT) {
      const char *krbtgt = "krbtgt";
      krb5_ret = krb5_build_principal_ext(krb5_ctx,
                  salt_princ,
                  strlen(upper_realm),
                  upper_realm,
                  strlen(krbtgt),
                  krbtgt,
                  computer_len,
                  sAMAccountName,
                  0);
      if (krb5_ret != 0) {
        TALLOC_FREE(frame);
        return krb5_ret;
      }
    } else {
      const char *host = "host";
      char *tmp = NULL;
      char *tmp_lower = NULL;

      tmp = talloc_asprintf(frame, "%*.*s.%s",
                computer_len,
                computer_len,
                sAMAccountName,
                realm);
      if (tmp == NULL) {
        TALLOC_FREE(frame);
        return ENOMEM;
      }

      tmp_lower = strlower_talloc(frame, tmp);
      if (tmp_lower == NULL) {
        TALLOC_FREE(frame);
        return ENOMEM;
      }

      krb5_ret = krb5_build_principal_ext(krb5_ctx,
                  salt_princ,
                  strlen(upper_realm),
                  upper_realm,
                  strlen(host),
                  host,
                  strlen(tmp_lower),
                  tmp_lower,
                  0);
      if (krb5_ret != 0) {
        TALLOC_FREE(frame);
        return krb5_ret;
      }
    }

  } else if (userPrincipalName != NULL) {
    /*
     * We parse the name not only to allow an easy
     * replacement of the realm (no matter the realm in
     * the UPN, the salt comes from the upper-case real
     * realm, but also to correctly provide a salt when
     * the UPN is host/foo.bar
     *
     * This can fail for a UPN of the form foo@bar@REALM
     * (which is accepted by windows) however.
     */
    krb5_ret = krb5_parse_name(krb5_ctx,
             userPrincipalName,
             salt_princ);

    if (krb5_ret != 0) {
      TALLOC_FREE(frame);
      return krb5_ret;
    }

    /*
     * No matter what realm (including none) in the UPN,
     * the realm is replaced with our upper-case realm
     */
    krb5_ret = smb_krb5_principal_set_realm(krb5_ctx,
              *salt_princ,
              upper_realm);
    if (krb5_ret != 0) {
      krb5_free_principal(krb5_ctx, *salt_princ);
      TALLOC_FREE(frame);
      return krb5_ret;
    }
  } else {
    principal = sAMAccountName;
    principal_len = strlen(principal);

    krb5_ret = krb5_build_principal_ext(krb5_ctx,
                salt_princ,
                strlen(upper_realm),
                upper_realm,
                principal_len,
                principal,
                0);
    if (krb5_ret != 0) {
      TALLOC_FREE(frame);
      return krb5_ret;
    }
  }

  TALLOC_FREE(frame);
  return 0;
}

/**
 * @brief This constructs the salt principal used by active directory
 *
 * Most Kerberos encryption types require a salt in order to
 * calculate the long term private key for user/computer object
 * based on a password.
 *
 * The returned _salt_principal is a string in forms like this:
 * - host/somehost.example.com@EXAMPLE.COM
 * - SomeAccount@EXAMPLE.COM
 * - SomePrincipal@EXAMPLE.COM
 *
 * This is not the form that's used as salt, it's just
 * the human readable form. It needs to be converted by
 * smb_krb5_salt_principal2data().
 *
 * @param[in]  realm              The realm the user/computer is added too.
 *
 * @param[in]  sAMAccountName     The sAMAccountName attribute of the object.
 *
 * @param[in]  userPrincipalName  The userPrincipalName attribute of the object
 *                                or NULL if not available.
 *
 * @param[in]  uac_flags          UF_ACCOUNT_TYPE_MASKed userAccountControl field
 *
 * @param[in]  mem_ctx            The TALLOC_CTX to allocate _salt_principal.
 *
 * @param[out]  _salt_principal   The resulting principal as string.
 *
 * @retval 0 Success; otherwise - Kerberos error codes
 *
 * @see smb_krb5_salt_principal2data
 */
int smb_krb5_salt_principal_str(const char *realm,
        const char *sAMAccountName,
        const char *userPrincipalName,
        uint32_t uac_flags,
        TALLOC_CTX *mem_ctx,
        char **_salt_principal_str)
{
  krb5_principal salt_principal = NULL;
  char *salt_principal_malloc;
  krb5_context krb5_ctx;
  krb5_error_code krb5_ret
    = smb_krb5_init_context_common(&krb5_ctx);
  if (krb5_ret != 0) {
    DBG_ERR("kerberos init context failed (%s)\n",
      error_message(krb5_ret));
    return krb5_ret;
  }

  krb5_ret = smb_krb5_salt_principal(krb5_ctx,
             realm,
             sAMAccountName,
             userPrincipalName,
             uac_flags,
             &salt_principal);
  if (krb5_ret != 0) {
    DBG_ERR("unable to create salt principal:%s\n",
      error_message(krb5_ret));
    return krb5_ret;
  }

  krb5_ret = krb5_unparse_name(krb5_ctx, salt_principal,
             &salt_principal_malloc);
  if (krb5_ret != 0) {
    krb5_free_principal(krb5_ctx, salt_principal);
    DBG_ERR("kerberos unparse of salt principal failed (%s)\n",
      error_message(krb5_ret));
    return krb5_ret;
  }
  krb5_free_principal(krb5_ctx, salt_principal);
  *_salt_principal_str
    = talloc_strdup(mem_ctx, salt_principal_malloc);
  krb5_free_unparsed_name(krb5_ctx, salt_principal_malloc);

  if (*_salt_principal_str == NULL) {
    return ENOMEM;
  }
  return 0;
}

/**
 * @brief Converts the salt principal string into the salt data blob
 *
 * This function takes a salt_principal as string in forms like this:
 * - host/somehost.example.com@EXAMPLE.COM
 * - SomeAccount@EXAMPLE.COM
 * - SomePrincipal@EXAMPLE.COM
 *
 * It generates values like:
 * - EXAMPLE.COMhost/somehost.example.com
 * - EXAMPLE.COMSomeAccount
 * - EXAMPLE.COMSomePrincipal
 *
 * @param[in]  realm              The realm the user/computer is added too.
 *
 * @param[in]  sAMAccountName     The sAMAccountName attribute of the object.
 *
 * @param[in]  userPrincipalName  The userPrincipalName attribute of the object
 *                                or NULL if not available.
 *
 * @param[in]  is_computer        The indication of the object includes
 *                                objectClass=computer.
 *
 * @param[in]  mem_ctx            The TALLOC_CTX to allocate _salt_principal.
 *
 * @param[out]  _salt_principal   The resulting principal as string.
 *
 * @retval 0 Success; otherwise - Kerberos error codes
 *
 * @see smb_krb5_salt_principal
 */
int smb_krb5_salt_principal2data(krb5_context context,
         const char *salt_principal,
         TALLOC_CTX *mem_ctx,
         char **_salt_data)
{
  krb5_error_code ret;
  krb5_principal salt_princ = NULL;
  krb5_data salt;

  *_salt_data = NULL;

  ret = krb5_parse_name(context, salt_principal, &salt_princ);
  if (ret != 0) {
    return ret;
  }

  ret = smb_krb5_get_pw_salt(context, salt_princ, &salt);
  krb5_free_principal(context, salt_princ);
  if (ret != 0) {
    return ret;
  }

  *_salt_data = talloc_strndup(mem_ctx,
             (char *)salt.data,
             salt.length);
  smb_krb5_free_data_contents(context, &salt);
  if (*_salt_data == NULL) {
    return ENOMEM;
  }

  return 0;
}

#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 krb5_free_enctypes() 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)
{
  return smb_krb5_parse_name_flags(context, name, 0, principal);
}

/**
 * @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[in]  flags    Flags for krb5_parse_name_flags()
 *
 * @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_flags(krb5_context context,
            const char *name,
            int flags,
            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_flags(context, utf8_name, flags, principal);
  if (ret != KRB5_PARSE_MALFORMED) {
    TALLOC_FREE(frame);
    return ret;
  }

  flags |= KRB5_PRINCIPAL_PARSE_ENTERPRISE;
  ret = krb5_parse_name_flags(context, utf8_name, flags, 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 principal 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
}

/*
 * @brief put a buffer reference into a krb5_data struct
 *
 * @param[in] data    The data to reference
 * @param[in] length    The length of the data to reference
 * @return krb5_data
 *
 * Caller should not free krb5_data.
 */
krb5_data smb_krb5_make_data(void *data,
           size_t len)
{
  krb5_data d;

#ifdef SAMBA4_USES_HEIMDAL
  d.data = (uint8_t *)data;
  d.length = len;
#else
  d.magic = KV5M_DATA;
  d.data = data;
  d.length = len;
#endif
  return d;
}

krb5_data smb_krb5_data_from_blob(DATA_BLOB blob)
{
  return smb_krb5_make_data(blob.data, blob.length);
}

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_s(mem_ctx,
            KRB5_KEY_DATA(skey),
            KRB5_KEY_LENGTH(skey));
  if (session_key->data == NULL) {
    DBG_WARNING("No memory for session key\n");
    goto done;
  }
  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
 * @param[out] out      The output string
 * @return krb5_error_code
 *
 * Caller must talloc_free if the return value is not NULL.
 *
 */
krb5_error_code smb_krb5_principal_get_comp_string(TALLOC_CTX *mem_ctx,
               krb5_context context,
               krb5_const_principal principal,
               unsigned int component,
               char **out)
{
  char *out_str = NULL;
#if defined(HAVE_KRB5_PRINCIPAL_GET_COMP_STRING)
  const char *str = NULL;

  str = krb5_principal_get_comp_string(context, principal, component);
  if (str == NULL) {
    return ENOENT;
  }

  out_str = talloc_strdup(mem_ctx, str);
  if (out_str == NULL) {
    return ENOMEM;
  }
#else
  krb5_data *data;

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

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

  out_str = talloc_strndup(mem_ctx, data->data, data->length);
  if (out_str == NULL) {
    return ENOMEM;
  }
#endif
  *out = out_str;
  return 0;
}

krb5_error_code smb_krb5_cc_new_unique_memory(krb5_context context,
                TALLOC_CTX *mem_ctx,
                char **ccache_name,
                krb5_ccache *id)
{
  krb5_error_code code;
  const char *type = NULL;
  const char *name = NULL;

  if (ccache_name != NULL) {
    *ccache_name = NULL;
  }
  *id = NULL;

#ifdef SAMBA4_USES_HEIMDAL
  /*
   * "MEMORY:anonymous" is not visible to
   * the credential cache collection iterator
   *
   * It creates anonymous-POINTER-UNIQUECOUNTTER
   * in the background.
   */
  code = krb5_cc_resolve(context, "MEMORY:anonymous", id);
  if (code != 0) {
    DBG_ERR("krb5_cc_resolve(MEMORY:anonymous) failed: %s\n",
      smb_get_krb5_error_message(
        context, code, mem_ctx));
    return code;
  }
#else /* MIT */
  /*
   * In MIT the "MEMORY:" credential cache collection
   * only contains the default cache (at most).
   */
  code = krb5_cc_new_unique(context, "MEMORY", NULL, id);
  if (code != 0) {
    DBG_ERR("krb5_cc_new_unique failed: %s\n",
      smb_get_krb5_error_message(
        context, code, mem_ctx));
    return code;
  }
#endif /* MIT */

  type = krb5_cc_get_type(context, *id);
  if (type == NULL) {
    DBG_ERR("krb5_cc_get_type failed...\n");
    krb5_cc_destroy(context, *id);
    *id = NULL;
    return KRB5_CC_UNKNOWN_TYPE;
  }

  name = krb5_cc_get_name(context, *id);
  if (name == NULL) {
    DBG_ERR("krb5_cc_get_name failed...\n");
    krb5_cc_destroy(context, *id);
    *id = NULL;
    return KRB5_CC_BADNAME;
  }

  if (ccache_name == NULL) {
    return 0;
  }

  *ccache_name = talloc_asprintf(mem_ctx, "%s:%s", type, name);
  if (*ccache_name == NULL) {
    DBG_ERR("krb5_cc_get_name failed...\n");
    krb5_cc_destroy(context, *id);
    *id = NULL;
    return ENOMEM;
  }

  return 0;
}

/**
 * @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 service 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 Success, 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);

  ret = smb_krb5_init_context_common(&context);
  if (ret) {
    DBG_ERR("kerberos init context failed (%s)\n",
      error_message(ret));
    goto done;
  }

  if (!ccache_string) {
    /*
     * A renew has low risk in mixing different
     * ccaches, so we allow callers to pass
     * NULL for the default cache.
     */
    ccache_string = smb_force_krb5_cc_default_name(context);
  }

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

  DBG_DEBUG("Using %s as ccache for client '%s' and service '%s'\n",
      ccache_string, client_string, service_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) {
    DBG_DEBUG("krb5_get_renewed_creds using ccache '%s' "
        "for client '%s' and service '%s' failed: %s\n",
        ccache_string, client_string, service_string,
        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 one 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 to the opened 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_kt_open_relative");
  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;
  }

  DBG_DEBUG("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:
  DBG_DEBUG("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 one 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 to the opened 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;
  }

  DBG_WARNING("ERROR: Invalid keytab name: %s\n", keytab_name_req);

  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]  keep_old_kvno Keep the entries with the previous kvno.
 *
 * @param[in]  kvno          The kvno to use.
 *
 * @param[in]  enctype_only  Only evaluate the enctype argument if true
 *
 * @param[in]  enctype       Only search for entries with the specified enctype
 *
 * @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         Whether to flush the complete keytab.
 *
 * @retval 0 on Success
 *
 * @return An appropriate KRB5 error code.
 */
krb5_error_code smb_krb5_kt_seek_and_delete_old_entries(krb5_context context,
              krb5_keytab keytab,
              bool keep_old_kvno,
              krb5_kvno kvno,
              bool enctype_only,
              krb5_enctype enctype,
              const char *princ_s,
              krb5_principal princ,
              bool flush)
{
  krb5_error_code ret;
  krb5_kt_cursor cursor;
  krb5_keytab_entry kt_entry;
  char *ktprinc = NULL;
  krb5_kvno old_kvno = kvno - 1;
  TALLOC_CTX *tmp_ctx;

  if (flush) {
    SMB_ASSERT(!keep_old_kvno);
    SMB_ASSERT(!enctype_only);
    SMB_ASSERT(princ_s == NULL);
    SMB_ASSERT(princ == NULL);
  } else {
    SMB_ASSERT(princ_s != NULL);
    SMB_ASSERT(princ != NULL);
  }

  ZERO_STRUCT(cursor);
  ZERO_STRUCT(kt_entry);

  /*
   * Start with talloc_new() and only then call krb5_kt_start_seq_get().
   * If any of them fails, the cleanup code is simpler.
   */
  tmp_ctx = talloc_new(NULL);
  if (tmp_ctx == NULL) {
    return ENOMEM;
  }

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

  DEBUG(3, (__location__ ": Will try to delete old keytab entries\n"));
  while (!samba_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 (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 kerberized 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 (keep_old_kvno && ((kt_entry.vno & 0xff) == (old_kvno & 0xff))) {
      DEBUG(5, (__location__ ": Saving previous (kvno %d) "
          "entry for principal: %s.\n",
          old_kvno,
          princ_s != NULL ? princ_s : "UNKNOWN"));
      continue;
    }

    if (enctype_only &&
        ((kt_entry.vno & 0xff) == (kvno & 0xff)) &&
        (kt_entry_enctype != enctype))
    {
      DEBUG(5, (__location__ ": Saving entry with kvno [%d] "
          "enctype [%d] for principal: %s.\n",
          kvno, kt_entry_enctype,
          princ_s != NULL ? princ_s : "UNKNOWN"));
      continue;
    }

    DEBUG(5, (__location__ ": Found old entry for principal: %s "
        "(kvno %d) - trying to remove it.\n",
        princ_s != NULL ? princ_s : "UNKNOWN",
        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 = samba_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 != NULL ? princ_s : "UNKNOWN",
        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 (!all_zero((uint8_t *)&kt_entry, sizeof(kt_entry))) {
    smb_krb5_kt_free_entry(context, &kt_entry);
  }
  if (!all_zero((uint8_t *)&cursor, sizeof(cursor))) {
    krb5_kt_end_seq_get(context, keytab, &cursor);
  }
  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.
 *
 * Initializes a new keyblock, allocates the contents for 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 needing the original password.
 *
 * @param[in]  ctx      The library context
 *
 * @param[in]  cc       The credential cache to put the tgt in.
 *
 * @param[in]  principal The client principal
 *
 * @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 expiration 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_kinit_keyblock_ccache"
  char tmp_name[64] = {0};
  krb5_keytab_entry entry;
  krb5_keytab keytab;
  int rc;

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

  rc = snprintf(tmp_name, sizeof(tmp_name),
          "%s-%p",
          SMB_CREDS_KEYTAB,
          &my_creds);
  if (rc < 0) {
    ZERO_STRUCT(entry);
    return KRB5_KT_BADNAME;
  }
  code = krb5_kt_resolve(ctx, tmp_name, &keytab);
  if (code) {
    ZERO_STRUCT(entry);
    return code;
  }

  code = krb5_kt_add_entry(ctx, keytab, &entry);
  ZERO_STRUCT(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 principal
 *
 * @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 expiration 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;
  }

  /*
   * 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;
  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 principal.
 *
 * @param[in]  password  The password (or NULL).
 *
 * @param[in]  impersonate_principal The impersonation 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 expiration 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;
  const char *client_realm = NULL;
  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 = smb_krb5_cc_new_unique_memory(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;
    }
    DBG_WARNING("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;
    }
    DBG_WARNING("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;
  }

  client_realm = krb5_principal_get_realm(ctx, store_creds.client);
  if (client_realm != NULL) {
    /*
     * Because the CANON flag doesn't have any impact
     * on the impersonate_principal => store_creds.client
     * realm mapping. We need to store the credentials twice,
     * once with the returned realm and once with the
     * realm of impersonate_principal.
     */
    code = krb5_principal_set_realm(ctx, store_creds.server,
            client_realm);
    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;
}

#else /* MIT */

static bool princ_compare_no_dollar(krb5_context ctx,
            krb5_principal a,
            krb5_principal b)
{
  krb5_principal mod = NULL;
  bool cmp;

  if (a->length == 1 && b->length == 1 &&
      a->data[0].length != 0 && b->data[0].length != 0 &&
      a->data[0].data[a->data[0].length - 1] !=
      b->data[0].data[b->data[0].length - 1]) {
    if (a->data[0].data[a->data[0].length - 1] == '$') {
      mod = a;
      mod->data[0].length--;
    } else if (b->data[0].data[b->data[0].length - 1] == '$') {
      mod = b;
      mod->data[0].length--;
    }
  }

  cmp = krb5_principal_compare_flags(ctx,
             a,
             b,
             KRB5_PRINCIPAL_COMPARE_CASEFOLD);
  if (mod != NULL) {
    mod->data[0].length++;
  }

  return cmp;
}

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;
  krb5_principal self_princ = NULL;
  krb5_principal target_princ = NULL;
  krb5_creds *store_creds = NULL;
  krb5_creds *s4u2self_creds = NULL;
  krb5_creds *s4u2proxy_creds = NULL;
  krb5_creds init_creds = {0};
  krb5_creds mcreds = {0};
  krb5_flags options = KRB5_GC_NO_STORE;
  krb5_ccache tmp_cc;
  bool s4u2proxy = false;
  bool ok;

  code = smb_krb5_cc_new_unique_memory(ctx, NULL, NULL, &tmp_cc);
  if (code != 0) {
    return code;
  }

  code = krb5_get_init_creds_password(ctx,
              &init_creds,
              init_principal,
              init_password,
              NULL,
              NULL,
              0,
              NULL,
              krb_options);
  if (code != 0) {
    goto done;
  }

  code = krb5_cc_initialize(ctx, tmp_cc, init_creds.client);
  if (code != 0) {
    goto done;
  }

  code = krb5_cc_store_cred(ctx, tmp_cc, &init_creds);
  if (code != 0) {
    goto done;
  }

  /*
   * 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;
  }

  code = krb5_parse_name(ctx, self_service, &self_princ);
  if (code != 0) {
    goto done;
  }

  /*
   * MIT lacks aliases support in S4U, for S4U2Self we require the tgt
   * client and the request server to be the same principal name.
   */
  ok = princ_compare_no_dollar(ctx, init_creds.client, self_princ);
  if (!ok) {
    code = KRB5KDC_ERR_PADATA_TYPE_NOSUPP;
    goto done;
  }

  mcreds.client = impersonate_principal;
  mcreds.server = init_creds.client;

  code = krb5_get_credentials_for_user(ctx, options, tmp_cc, &mcreds,
               NULL, &s4u2self_creds);
  if (code != 0) {
    goto done;
  }

  if (s4u2proxy) {
    code = krb5_parse_name(ctx, target_service, &target_princ);
    if (code != 0) {
      goto done;
    }

    mcreds.client = init_creds.client;
    mcreds.server = target_princ;
    mcreds.second_ticket = s4u2self_creds->ticket;

    code = krb5_get_credentials(ctx, options |
              KRB5_GC_CONSTRAINED_DELEGATION,
              tmp_cc, &mcreds, &s4u2proxy_creds);
    if (code != 0) {
      goto done;
    }

    /* Check KDC support of S4U2Proxy extension */
    if (!krb5_principal_compare(ctx, s4u2self_creds->client,
              s4u2proxy_creds->client)) {
      code = KRB5KDC_ERR_PADATA_TYPE_NOSUPP;
      goto done;
    }

    store_creds = s4u2proxy_creds;
  } else {
    store_creds = s4u2self_creds;;

    /* We need to save the ticket with the requested server name
     * or the caller won't be able to find it in cache. */
    if (!krb5_principal_compare(ctx, self_princ,
      store_creds->server)) {
      krb5_free_principal(ctx, store_creds->server);
      store_creds->server = NULL;
      code = krb5_copy_principal(ctx, self_princ,
               &store_creds->server);
      if (code != 0) {
        goto done;
      }
    }
  }

  code = krb5_cc_initialize(ctx, store_cc, store_creds->client);
  if (code != 0) {
    goto done;
  }

  code = krb5_cc_store_cred(ctx, store_cc, store_creds);
  if (code != 0) {
    goto done;
  }

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

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

done:
  krb5_cc_destroy(ctx, tmp_cc);
  krb5_free_cred_contents(ctx, &init_creds);
  krb5_free_creds(ctx, s4u2self_creds);
  krb5_free_creds(ctx, s4u2proxy_creds);
  krb5_free_principal(ctx, self_princ);
  krb5_free_principal(ctx, target_princ);

  return code;
}
#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 endtime = 0;
  krb5_timestamp now;
  char *realm = NULL;
  TALLOC_CTX *mem_ctx = NULL;

  *t = 0;

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

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

  mem_ctx = talloc_stackframe();
  if (mem_ctx == NULL) {
          krb5_cc_end_seq_get(context, id, &cursor);
    return ENOMEM;
  }

  while ((kerr = krb5_cc_next_cred(context, id, &cursor, &cred)) == 0) {
    if (krb5_is_config_principal(context, cred.server)) {
      krb5_free_cred_contents(context, &cred);
      continue;
    }

    realm = smb_krb5_principal_get_realm(mem_ctx, context, cred.server);
    if (realm == NULL) {
      krb5_free_cred_contents(context, &cred);
      kerr = ENOMEM;
      break;
    }

    /*
     * 'X-GSSPROXY:' is the realm for an encrypted credential stored
     * by the GSSProxy. There are no other creds in such ccache and
     * we cannot see the actual lifetime (it is set to 0),
     * indicate to the caller they need to handle this themselves.
     */
    if (strcmp(realm, "X-GSSPROXY:") == 0) {
      krb5_free_cred_contents(context, &cred);
      kerr = KRB5_PLUGIN_NO_HANDLE;
      break;
    }

#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) {
        endtime = cred.times.endtime;
      }
      krb5_free_cred_contents(context, &cred);
      break;
    }

    if (cred.times.endtime <= now) {
      /* already expired */
      krb5_free_cred_contents(context, &cred);
      continue;
    }

    /**
     * If there was no krbtgt, use the shortest lifetime of
     * service tickets that have yet to expire.  If all
     * credentials are expired, krb5_cc_get_lifetime() will fail.
     */
    if (endtime == 0 || cred.times.endtime < endtime) {
      endtime = cred.times.endtime;
    }
    krb5_free_cred_contents(context, &cred);
  }

  krb5_cc_end_seq_get(context, id, &cursor);
  talloc_free(mem_ctx);
  if (kerr == ENOMEM || kerr == KRB5_PLUGIN_NO_HANDLE) {
    return kerr;
  }

  if (now < endtime) {
    *t = (time_t) (endtime - now);
    kerr = 0;
  }

  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 allocate 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] mem_ctx   The talloc ctx to put the result on
 *
 * @param[in] context   The library context
 *
 * @param[in] principal The principal to get the realm from.
 *
 * @return A talloced string with the realm or NULL if an error occurred.
 */
char *smb_krb5_principal_get_realm(TALLOC_CTX *mem_ctx,
           krb5_context context,
           krb5_const_principal principal)
{
#ifdef HAVE_KRB5_PRINCIPAL_GET_REALM /* Heimdal */
  const char *realm = NULL;

  realm = krb5_principal_get_realm(context, principal);
  if (realm == NULL) {
    return NULL;
  }

  return talloc_strdup(mem_ctx, realm);
#elif defined(krb5_princ_realm) /* MIT */
  const krb5_data *realm = NULL;

  realm = krb5_princ_realm(context, principal);
  if (realm == NULL) {
    return NULL;
  }

  return talloc_strndup(mem_ctx, 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.
 *
 * @return 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
}


/**
 * @brief Get the realm from the service hostname.
 *
 * This function will look for a domain realm mapping in the [domain_realm]
 * section of the krb5.conf first and fallback to extract the realm from
 * the provided service hostname. As a last resort it will return the
 * provided client_realm.
 *
 * @param[in]  mem_ctx     The talloc context
 *
 * @param[in]  hostname    The service hostname
 *
 * @param[in]  client_realm  If we can not find a mapping, fall back to
 *                           this realm.
 *
 * @return The realm to use for the service hostname, NULL if a fatal error
 *         occurred.
 */
char *smb_krb5_get_realm_from_hostname(TALLOC_CTX *mem_ctx,
               const char *hostname,
               const char *client_realm)
{
#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;

  kerr = smb_krb5_init_context_common(&ctx);
  if (kerr) {
    DBG_ERR("kerberos init context failed (%s)\n",
      error_message(kerr));
    return NULL;
  }

  kerr = krb5_get_host_realm(ctx, hostname, &realm_list);
  if (kerr == KRB5_ERR_HOST_REALM_UNKNOWN) {
    realm_list = NULL;
    kerr = 0;
  }
  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 != NULL &&
      realm_list[0] != NULL &&
      realm_list[0][0] != '\0') {
    realm = talloc_strdup(mem_ctx, realm_list[0]);
    if (realm == NULL) {
      goto out;
    }
  } else {
    const char *p = NULL;

    /*
     * "dc6.samba2003.example.com"
     * returns a realm of "SAMBA2003.EXAMPLE.COM"
     *
     * "dc6." returns realm as NULL
     */
    p = strchr_m(hostname, '.');
    if (p != NULL && p[1] != '\0') {
      realm = talloc_strdup_upper(mem_ctx, p + 1);
      if (realm == NULL) {
        goto out;
      }
    }
  }

  if (realm == NULL) {
    realm = talloc_strdup(mem_ctx, client_realm);
  }

  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 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 occurred.
 *
 * 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 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
}

/**
 * @brief Check if a principal is a TGS
 *
 * @param[in]  context  The library context
 *
 * @param[inout] principal The principal to check.
 *
 * @returns 1 if equal, 0 if not and -1 on error.
 */
int smb_krb5_principal_is_tgs(krb5_context context,
            krb5_const_principal principal)
{
  char *p = NULL;
  int eq = 1;
  krb5_error_code ret = 0;

  if (krb5_princ_size(context, principal) > 2) {
    return 0;
  }

  ret = smb_krb5_principal_get_comp_string(NULL, context, principal, 0, &p);
  if (ret == ENOENT) {
    return 0;
  } else if (ret) {
    return -1;
  }

  eq = strcmp(p, KRB5_TGS_NAME) == 0;

  talloc_free(p);

  return eq;
}

#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 executable
  */
  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 delegated 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 && in_data->data != NULL) {
    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[] = {
    ENCTYPE_AES256_CTS_HMAC_SHA1_96,
    ENCTYPE_AES128_CTS_HMAC_SHA1_96,
    ENCTYPE_ARCFOUR_HMAC,
    ENCTYPE_NULL};
  bool ok;

  if (ccname == NULL) {
    DBG_ERR("No explicit ccache given for service [%s], "
      "impersonating [%s]\n",
      principal, impersonate_princ_s);
    retval = EINVAL;
    goto failed;
  }

  DBG_DEBUG("Getting ticket for service [%s] using creds from [%s] "
      "and impersonating [%s]\n",
      principal, ccname, impersonate_princ_s);

  retval = smb_krb5_init_context_common(&context);
  if (retval != 0) {
    DBG_ERR("kerberos 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, &ccdef);
  if (retval != 0) {
    DBG_WARNING("krb5_cc_resolve(%s) failed (%s)\n",
          ccname, 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;
}

#ifndef SAMBA4_USES_HEIMDAL /* MITKRB5 tracing callback */
static void smb_krb5_trace_cb(krb5_context ctx,
#ifdef HAVE_KRB5_TRACE_INFO
            const krb5_trace_info *info,
#elif defined(HAVE_KRB5_TRACE_INFO_STRUCT)
            const struct krb5_trace_info *info,
#else
#error unknown krb5_trace_info
#endif
            void *data)
{
  if (info != NULL) {
    DBGC_DEBUG(DBGC_KERBEROS, "%s", info->message);
  }
}
#endif

krb5_error_code smb_krb5_init_context_common(krb5_context *_krb5_context)
{
  krb5_error_code ret;
  krb5_context krb5_ctx;

  initialize_krb5_error_table();

  ret = krb5_init_context(&krb5_ctx);
  if (ret) {
    DBG_ERR("Krb5 context initialization failed (%s)\n",
       error_message(ret));
    return ret;
  }

  /* The MIT Kerberos build relies on using the system krb5.conf file.
   * If you really want to use another file please set KRB5_CONFIG
   * accordingly. */
#ifndef SAMBA4_USES_HEIMDAL
  ret = krb5_set_trace_callback(krb5_ctx, smb_krb5_trace_cb, NULL);
  if (ret) {
    DBG_ERR("Failed to set MIT kerberos trace callback! (%s)\n",
      error_message(ret));
  }
#endif

#ifdef SAMBA4_USES_HEIMDAL
  /* Set options in kerberos */
  krb5_set_dns_canonicalize_hostname(krb5_ctx, false);
#endif

  *_krb5_context = krb5_ctx;
  return 0;
}

/*
 * This should only be used in code that
 * really wants to touch the global default ccache!
 */
krb5_error_code smb_force_krb5_cc_default(krb5_context ctx, krb5_ccache *id)
{
#undef krb5_cc_default
  return krb5_cc_default(ctx, id);
#define krb5_cc_default __ERROR__XX__NEVER_USE_krb5_cc_default__;
}

/*
 * This should only be used in code that
 * really wants to touch the global default ccache!
 */
const char *smb_force_krb5_cc_default_name(krb5_context ctx)
{
#undef krb5_cc_default_name
  return krb5_cc_default_name(ctx);
#define krb5_cc_default_name __ERROR__XX__NEVER_USE_krb5_cc_default_name__;
}

#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 */

Coverage Report

Created: 2026-01-16 06:47