server.c 4.63 KB
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/* server.c
 *
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 *
 *
 * $Id$ */

/* lsh, an implementation of the ssh protocol
 *
 * Copyright (C) 1998 Niels Möller
 *
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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 */

#include "server.h"

#include "abstract_io.h"
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#include "connection.h"
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#include "debug.h"
#include "format.h"
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#include "keyexchange.h"
#include "read_line.h"
#include "read_packet.h"
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#include "unpad.h"
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#include "version.h"
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#include "werror.h"
#include "xalloc.h"

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struct server_callback
{
  struct fd_callback super;
  struct io_backend *backend;

  struct signer *secret;        /* secret key */
  struct lsh_string *host_key;  /* public key */
  UINT32 block_size;
  char *id_comment;

  struct randomness *random;
  struct make_kexinit *init;
  struct packet_handler *kexinit_handler;
};

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static int server_initiate(struct fd_callback **c,
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			   int fd)
{
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  struct server_callback *closure = (struct server_callback *) *c;
  
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  struct ssh_connection *connection
    = make_ssh_connection(closure->kexinit_handler);

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  int res;
  
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  verbose("server_initiate()\n");
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  connection_init_io(connection,
		     io_read_write(closure->backend, fd,
				   make_server_read_line(connection),
				   closure->block_size,
				   make_server_close_handler()),
		     closure->random);

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  connection->server_version
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    = ssh_format("SSH-%lz-%lz %lz",
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		 PROTOCOL_VERSION,
		 SOFTWARE_SERVER_VERSION,
		 closure->id_comment);
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  res = A_WRITE(connection->raw,
		 ssh_format("%lS\r\n", connection->server_version));
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  if (LSH_CLOSEDP(res))
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    return res;

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  return res | initiate_keyexchange(connection, CONNECTION_SERVER,
				    MAKE_KEXINIT(closure->init),
				    NULL);
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}

struct server_line_handler
{
  struct line_handler super;
  struct ssh_connection *connection;
};

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static struct read_handler *do_line(struct line_handler **h,
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				    UINT32 length,
				    UINT8 *line)
{
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  struct server_line_handler *closure = (struct server_line_handler *) *h;
  
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  MDEBUG(closure);
  
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  if ( (length >= 4) && !memcmp(line, "SSH-", 4))
    {
      /* Parse and remember format string */
      if ((length >= 8) && !memcmp(line + 4, "2.0-", 4))
	{
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	  struct read_handler *new = make_read_packet
	    (make_packet_unpad
	     (make_packet_debug(&closure->connection->super,
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				"recieved")),
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	     closure->connection);
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	  closure->connection->client_version
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	    = ssh_format("%ls", length, line);
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	  verbose("Client version: ");
	  verbose_safe(closure->connection->client_version->length,
		       closure->connection->client_version->data);
	  verbose("\n");
	  
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	  /* FIXME: Cleanup properly. */
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	  lsh_free(closure);
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	  return new;
	}
      else
	{
	  werror("Unsupported protocol version: ");
	  werror_safe(length, line);
	  werror("\n");

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	  /* FIXME: Clean up properly */
	  lsh_free(closure);
	  *h = 0;
		  
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	  return 0;
	}
    }
  else
    {
      /* Display line */
      werror_safe(length, line);

      /* Read next line */
      return 0;
    }
}
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struct read_handler *make_server_read_line(struct ssh_connection *c)
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{
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  struct server_line_handler *closure;

  NEW(closure);
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  closure->super.handler = do_line;
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  closure->connection = c;
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  return make_read_line(&closure->super);
}

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struct fd_callback *
make_server_callback(struct io_backend *b,
		     char *comment,
		     UINT32 block_size,
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		     struct randomness *random,
		     struct make_kexinit *init,
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		     struct packet_handler *kexinit_handler)
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{
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  struct server_callback *connected;

  NEW(connected);
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  connected->super.f = server_initiate;
  connected->backend = b;
  connected->block_size = block_size;
  connected->id_comment = comment;
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  connected->random = random;  
  connected->init = init;
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  connected->kexinit_handler = kexinit_handler;
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  return &connected->super;
}

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static int server_die(struct close_callback *closure, int reason)
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{
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  verbose("Connection died, for reason %d.\n", reason);
  if (reason != CLOSE_EOF)
    werror("Connection died.\n");

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  return 0;  /* Ignored */
}

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struct close_callback *make_server_close_handler(void)
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{
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  struct close_callback *c;

  NEW(c);
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  c->f = server_die;

  return c;
}