/*
   Bacula® - The Network Backup Solution

   Copyright (C) 2000-2007 Free Software Foundation Europe e.V.

   The main author of Bacula is Kern Sibbald, with contributions from
   many others, a complete list can be found in the file AUTHORS.
   This program is Free Software; you can redistribute it and/or
   modify it under the terms of version two of the GNU General Public
   License as published by the Free Software Foundation and included
   in the file LICENSE.

   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, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.

   Bacula® is a registered trademark of John Walker.
   The licensor of Bacula is the Free Software Foundation Europe
   (FSFE), Fiduciary Program, Sumatrastrasse 25, 8006 Zürich,
   Switzerland, email:ftf@fsfeurope.org.
*/
/*
 * Authenticate Director who is attempting to connect.
 *
 *   Kern Sibbald, October 2000
 *
 *   Version $Id: authenticate.c 5713 2007-10-03 11:36:47Z kerns $
 *
 */

#include "bacula.h"
#include "filed.h"

const int dbglvl = 50;

static char OK_hello[]  = "2000 OK Hello\n";
static char Dir_sorry[] = "2999 No go\n";
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

/*********************************************************************
 *
 */
static bool authenticate(int rcode, BSOCK *bs, JCR* jcr)
{
   POOLMEM *dirname = get_pool_memory(PM_MESSAGE);
   DIRRES *director = NULL;
   int tls_local_need = BNET_TLS_NONE;
   int tls_remote_need = BNET_TLS_NONE;
   int compatible = true;                 /* Want md5 compatible DIR */
   bool auth_success = false;
   alist *verify_list = NULL;
   btimer_t *tid = NULL;

   if (rcode != R_DIRECTOR) {
      Dmsg1(dbglvl, "I only authenticate directors, not %d\n", rcode);
      Emsg1(M_FATAL, 0, _("I only authenticate directors, not %d\n"), rcode);
      goto auth_fatal;
   }
   if (bs->msglen < 25 || bs->msglen > 500) {
      Dmsg2(dbglvl, "Bad Hello command from Director at %s. Len=%d.\n",
            bs->who(), bs->msglen);
      char addr[64];
      char *who = bnet_get_peer(bs, addr, sizeof(addr)) ? bs->who() : addr;
      Emsg2(M_FATAL, 0, _("Bad Hello command from Director at %s. Len=%d.\n"),
             who, bs->msglen);
      goto auth_fatal;
   }
   dirname = check_pool_memory_size(dirname, bs->msglen);

   if (sscanf(bs->msg, "Hello Director %s calling", dirname) != 1) {
      char addr[64];
      char *who = bnet_get_peer(bs, addr, sizeof(addr)) ? bs->who() : addr;
      bs->msg[100] = 0;
      Dmsg2(dbglvl, "Bad Hello command from Director at %s: %s\n",
            bs->who(), bs->msg);
      Emsg2(M_FATAL, 0, _("Bad Hello command from Director at %s: %s\n"),
            who, bs->msg);
      goto auth_fatal;
   }
   unbash_spaces(dirname);
   foreach_res(director, R_DIRECTOR) {
      if (strcmp(director->hdr.name, dirname) == 0)
         break;
   }
   if (!director) {
       char addr[64];
       char *who = bnet_get_peer(bs, addr, sizeof(addr)) ? bs->who() : addr;
      Emsg2(M_FATAL, 0, _("Connection from unknown Director %s at %s rejected.\n"), 
            dirname, who);
      goto auth_fatal;
   }

   if (have_tls) {
      /* TLS Requirement */
      if (director->tls_enable) {
         if (director->tls_require) {
            tls_local_need = BNET_TLS_REQUIRED;
         } else {
            tls_local_need = BNET_TLS_OK;
         }
      }

      if (director->tls_verify_peer) {
         verify_list = director->tls_allowed_cns;
      }
   }

   tid = start_bsock_timer(bs, AUTH_TIMEOUT);
   /* Challenge the director */
   auth_success = cram_md5_challenge(bs, director->password, tls_local_need, compatible);  
   if (job_canceled(jcr)) {
      auth_success = false;
      goto auth_fatal;                   /* quick exit */
   }
   if (auth_success) {
      auth_success = cram_md5_respond(bs, director->password, &tls_remote_need, &compatible);
      if (!auth_success) {
          char addr[64];
          char *who = bnet_get_peer(bs, addr, sizeof(addr)) ? bs->who() : addr;
          Dmsg1(dbglvl, "cram_get_auth failed for %s\n", who);
      }
   } else {
       char addr[64];
       char *who = bnet_get_peer(bs, addr, sizeof(addr)) ? bs->who() : addr;
       Dmsg1(dbglvl, "cram_auth failed for %s\n", who);
   }
   if (!auth_success) {
       Emsg1(M_FATAL, 0, _("Incorrect password given by Director at %s.\n"),
             bs->who());
       goto auth_fatal;
   }

   /* Verify that the remote host is willing to meet our TLS requirements */
   if (tls_remote_need < tls_local_need && tls_local_need != BNET_TLS_OK && tls_remote_need != BNET_TLS_OK) {
      Emsg0(M_FATAL, 0, _("Authorization problem: Remote server did not"
           " advertize required TLS support.\n"));
      auth_success = false;
      goto auth_fatal;
   }

   /* Verify that we are willing to meet the remote host's requirements */
   if (tls_remote_need > tls_local_need && tls_local_need != BNET_TLS_OK && tls_remote_need != BNET_TLS_OK) {
      Emsg0(M_FATAL, 0, _("Authorization problem: Remote server requires TLS.\n"));
      auth_success = false;
      goto auth_fatal;
   }

   if (have_tls) {
      if (tls_local_need >= BNET_TLS_OK && tls_remote_need >= BNET_TLS_OK) {
         /* Engage TLS! Full Speed Ahead! */
         if (!bnet_tls_server(director->tls_ctx, bs, verify_list)) {
            Emsg0(M_FATAL, 0, _("TLS negotiation failed.\n"));
            auth_success = false;
            goto auth_fatal;
         }
      }
   }

auth_fatal:
   if (tid) {
      stop_bsock_timer(tid);
      tid = NULL;
   }
   free_pool_memory(dirname);
   jcr->director = director;
   /* Single thread all failures to avoid DOS */
   if (!auth_success) {
      P(mutex);
      bmicrosleep(6, 0);
      V(mutex);
   }
   return auth_success;
}

/*
 * Inititiate the communications with the Director.
 * He has made a connection to our server.
 *
 * Basic tasks done here:
 *   We read Director's initial message and authorize him.
 *
 */
int authenticate_director(JCR *jcr)
{
   BSOCK *dir = jcr->dir_bsock;

   if (!authenticate(R_DIRECTOR, dir, jcr)) {
      bnet_fsend(dir, "%s", Dir_sorry);
      Emsg0(M_FATAL, 0, _("Unable to authenticate Director\n"));
      return 0;
   }
   return bnet_fsend(dir, "%s", OK_hello);
}

/*
 * First prove our identity to the Storage daemon, then
 * make him prove his identity.
 */
int authenticate_storagedaemon(JCR *jcr)
{
   BSOCK *sd = jcr->store_bsock;
   int tls_local_need = BNET_TLS_NONE;
   int tls_remote_need = BNET_TLS_NONE;
   int compatible = true;
   bool auth_success = false;

   btimer_t *tid = start_bsock_timer(sd, AUTH_TIMEOUT);

   /* TLS Requirement */
   if (have_tls && me->tls_enable) {
      if (me->tls_require) {
         tls_local_need = BNET_TLS_REQUIRED;
      } else {
         tls_local_need = BNET_TLS_OK;
      }
   }

   if (job_canceled(jcr)) {
      auth_success = false;     /* force quick exit */
      goto auth_fatal;
   }

   /* Respond to SD challenge */
   auth_success = cram_md5_respond(sd, jcr->sd_auth_key, &tls_remote_need, &compatible);
   if (job_canceled(jcr)) {
      auth_success = false;     /* force quick exit */
      goto auth_fatal;
   }
   if (!auth_success) {
      Dmsg1(dbglvl, "cram_respond failed for %s\n", sd->who());
   } else {
      /* Now challenge him */
      auth_success = cram_md5_challenge(sd, jcr->sd_auth_key, tls_local_need, compatible);
      if (!auth_success) {
         Dmsg1(dbglvl, "cram_challenge failed for %s\n", sd->who());
      }
   }

   if (!auth_success) {
      Jmsg(jcr, M_FATAL, 0, _("Authorization key rejected by Storage daemon.\n"
       "Please see http://www.bacula.org/rel-manual/faq.html#AuthorizationErrors for help.\n"));
      goto auth_fatal;
   }

   /* Verify that the remote host is willing to meet our TLS requirements */
   if (tls_remote_need < tls_local_need && tls_local_need != BNET_TLS_OK && tls_remote_need != BNET_TLS_OK) {
      Jmsg(jcr, M_FATAL, 0, _("Authorization problem: Remote server did not" 
           " advertise required TLS support.\n"));
      auth_success = false;
      goto auth_fatal;
   }

   /* Verify that we are willing to meet the remote host's requirements */
   if (tls_remote_need > tls_local_need && tls_local_need != BNET_TLS_OK && tls_remote_need != BNET_TLS_OK) {
      Jmsg(jcr, M_FATAL, 0, _("Authorization problem: Remote server requires TLS.\n"));
      auth_success = false;
      goto auth_fatal;
   }

   if (have_tls && tls_local_need >= BNET_TLS_OK && tls_remote_need >= BNET_TLS_OK) {
      /* Engage TLS! Full Speed Ahead! */
      if (!bnet_tls_client(me->tls_ctx, sd, NULL)) {
         Jmsg(jcr, M_FATAL, 0, _("TLS negotiation failed.\n"));
         auth_success = false;
         goto auth_fatal;
      }
   }

auth_fatal:
   /* Destroy session key */
   memset(jcr->sd_auth_key, 0, strlen(jcr->sd_auth_key));
   stop_bsock_timer(tid);
   /* Single thread all failures to avoid DOS */
   if (!auth_success) {
      P(mutex);
      bmicrosleep(6, 0);
      V(mutex);
   }
   return auth_success;
}