/*

   Unix SMB/CIFS implementation.

   SASL/EXTERNAL authentication.

   Copyright (C) Howard Chu <hyc@symas.com> 2013

   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 <tevent.h>

#include "lib/util/tevent_ntstatus.h"

#include "auth/credentials/credentials.h"

#include "auth/gensec/gensec.h"

#include "auth/gensec/gensec_internal.h"

#include "auth/gensec/gensec_proto.h"

#include "auth/gensec/gensec_toplevel_proto.h"

#undef DBGC_CLASS

#define DBGC_CLASS DBGC_AUTH

/* SASL/EXTERNAL is essentially a no-op; it is only usable when the transport

 * layer is already mutually authenticated.

 */

NTSTATUS gensec_external_init(TALLOC_CTX *ctx);

static NTSTATUS gensec_external_start(struct gensec_security *gensec_security)

{

  if (gensec_security->want_features & GENSEC_FEATURE_SIGN)

    return NT_STATUS_INVALID_PARAMETER;

  if (gensec_security->want_features & GENSEC_FEATURE_SEAL)

    return NT_STATUS_INVALID_PARAMETER;

  return NT_STATUS_OK;

}

struct gensec_external_update_state {

  DATA_BLOB out;

};

static struct tevent_req *gensec_external_update_send(TALLOC_CTX *mem_ctx,

          struct tevent_context *ev,

          struct gensec_security *gensec_security,

          const DATA_BLOB in)

{

  struct tevent_req *req;

  struct gensec_external_update_state *state = NULL;

  req = tevent_req_create(mem_ctx, &state,

        struct gensec_external_update_state);

  if (req == NULL) {

    return NULL;

  }

  state->out = data_blob_talloc(state, "", 0);

  if (tevent_req_nomem(state->out.data, req)) {

    return tevent_req_post(req, ev);

  }

  tevent_req_done(req);

  return tevent_req_post(req, ev);

}

static NTSTATUS gensec_external_update_recv(struct tevent_req *req,

              TALLOC_CTX *out_mem_ctx,

              DATA_BLOB *out)

{

  struct gensec_external_update_state *state =

    tevent_req_data(req,

    struct gensec_external_update_state);

  NTSTATUS status;

  *out = data_blob_null;

  if (tevent_req_is_nterror(req, &status)) {

    tevent_req_received(req);

    return status;

  }

  *out = state->out;

  tevent_req_received(req);

  return NT_STATUS_OK;

}

/* We have no features */

static bool gensec_external_have_feature(struct gensec_security *gensec_security,

             uint32_t feature)

{

  return false;

}

static const struct gensec_security_ops gensec_external_ops = {

  .name             = "sasl-EXTERNAL",

  .sasl_name        = "EXTERNAL",

  .client_start     = gensec_external_start,

  .update_send      = gensec_external_update_send,

  .update_recv      = gensec_external_update_recv,

  .have_feature     = gensec_external_have_feature,

  .enabled          = true,

  .priority         = GENSEC_EXTERNAL

};

NTSTATUS gensec_external_init(TALLOC_CTX *ctx)

{

  NTSTATUS ret;

  ret = gensec_register(ctx, &gensec_external_ops);

  if (!NT_STATUS_IS_OK(ret)) {

    DEBUG(0,("Failed to register '%s' gensec backend!\n",

       gensec_external_ops.name));

  }

  return ret;

}