post-install:

	${STRIP_CMD} ${STAGEDIR}${PREFIX}/sbin/identd

# Add the following line to /etc/rc.conf[.local] to enable fakeident.

#

# fakeidentd_enable (bool):      Set to 'YES' to enable

#                               Default: NO

. /etc/rc.subr

#if 0 /*

#	This program is easy to compile. For example the following ways:

#		$ sh identd.c

#		$ sh identd.c -g -DDEBUG

#		$ sh identd.c -s -DXXXMULTI

#		$ CC=cc sh identd.c

#		$ CC=egcs sh identd.c -s -fomit-frame-pointer

NAME=`basename $0 .c`

[ x`uname` = xSunOS ] && L="-lsocket -lnsl" || L=

[ x$1 = x ] && set -- -s -O2

CMDLINE="${CC:-gcc} -Wall $@ -o $NAME $NAME.c $L"

echo $CMDLINE; exec $CMDLINE; exit -1

# */

#endif

/*

 * $Id: identd.c,v 1.7 2002/09/29 07:50:20 too Stab $

 *

 * Author: Tomi Ollila <too@iki.fi>

 *

 * Created: Sat Nov 25 15:34:07 1995 too

 * Last modified: Sun Sep 29 10:48:42 2002 too

 *

 * This program is standalone 'fake' ident daemon. This program does

 * not fork() but is configured to handle up to 20 concurrent connections.

 * Since one connection should not last long, if all 20 connections are

 * in use, the next connection will close the oldest connection data

 * has been read. This way this program is not very vulnerable to so

 * called `denial of service' attack, thus making this ideal "identd"

 * to be used in a firewall.

 *

 * Program takes one (or many) arguments, which if exist, determines the

 * `user' name(s) that is returned for successful ident query.

 *

 * 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, 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.

 *

 * HISTORY

 * $Log: identd.c,v $

 *

 * Revision 1.7  2002/09/29 07:50:20  too

 *   No longer chops up to IDSTR_MAX chars, but uses "%.*s" to limit length;

 *	now works also when XXXMULTI defined.

 *   Back-hacked self-compilable trick, with more tricks to avoid compiler

 *	warnings.

 *   Removed own define of FD_SETSIZE altogether;

 *	systems has it small to begin with.

 *   Line '415' (or whatever that is now) fixed. () -> (void) in func def.

 *   Some fine tuning.

 *   Thanks to Cristian for his patches.

 *

 * Revision 1.6.1  2002-09-28 12:30:29 +0200  cii

 *   + added defines for IDSTR_MAX, IDENT_SUBSTR, IDSTR_BUFLEN and IDSTR_MAX

 *     (length limit on the id-string)

 *   + program arg 1 chopped after IDSTR_MAX characters (when applicable);

 *     reason is:

 *       - if the program is called with a relativelly long string as arg 1

 *         (tested with about 400 chars), a segfault occurs due to an internal

 *         buffer overflow (buffer space reserved for id-string is 128 chars,

 *         but never verified)

 *       - it may trigger buffer overflows in clients

 *   + put a proper comment at the top of the file

 *   + sorted out FD_SETSIZE (on Linux it's already defined)

 *       - moved it down below all the includes

 *   + added time.h include

 *   + added some short comments

 *   + conditionals '{', '}' enclosed

 *   + variable index -> idx in function closeOldest (killed a warning)

 *   + splitted multiple statements on a singel line

 *   + splitted long lines

 *   + prototypes ending in '()' -> '(void)'; changed by protoize

 *   + corrected most warnings, but "function declaration isn't a prototype"

 *     which still occurs on line: 415

 *   + added IDENT_PORT

 *   + added IDENT_SUBSTR

 *

 * Revision 1.6  2002/07/31 16:25:20  too

 * Now works when started as root (in Linux). Stupid me, tested

 * only starting as an ordinary loser.

 *

 * Revision 1.5  2002/07/29 14:02:42  too

 * Added possibility to have multible reply users, one (pseudo)randomly

 * chosen at each time.

 *

 * Revision 1.4  2001/02/09 08:45:42  too

 * Now GID is also changed to nobody/nogroup.

 *

 * Revision 1.3  2000/06/07 05:55:44  too

 * Fixed some Solaris compilation "bugs".

 * Changed LOG_PERROR to LOG_CONS

 *

 * Revision 1.2  1999/07/30 04:08:42  too

 * Added printing version string (and exit) with `-V' command line option.

 *

 * Revision 1.1  1999/04/21 17:23:20  too

 * - Writes process id to /var/run/identd.pid.

 * - Changes (effective) user id to `nobody' after initialization

 *	(binding socket etc.).

 * - Ignores some signals (HUP and PIPE).

 * - Handles some signals that aborts by default. The handler function

 *	tries to get rid of the pidfile.

 *

 * Revision 0.9b 1999/04/15 20:45:12  too

 * Not so much spaghetti anymore. Added documentation and more replies.

 *

 * Revision 0.9  1999/04/12 18:30:00  too

 * Version for unix systems. Standalone, supports 20 concurrent connections.

 * The code is quite a spaghetti. But that does not matter.

 *

 */

#include <unistd.h>

#include <stdio.h>

#include <stdlib.h>

#include <stdarg.h>

#include <string.h>

#include <fcntl.h>

#include <signal.h>

#include <syslog.h>

#include <pwd.h>

#include <netdb.h>

#include <sys/syslog.h>

#include <sys/types.h>

#include <sys/time.h>

#include <time.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <errno.h>

#define IDENT_PORT	113

#define IDENT_SUBSTR	": USERID : UNIX :"

#define MAXCONNS	20

#define MAXIDLETIME	45

#define IDSTR_BUFLEN	128 /*could be dropped down to 64 if tight in memory */

/*

 * format string is: "%d, %d " IDENT_SUBSTR " %.*s\r\n"

 * %d is max 999999999 (allowed by this identd, 

 */

#define IDSTR_MAX	(IDSTR_BUFLEN - 1) - \

	9 - 2 - 9 - 1 - (sizeof IDENT_SUBSTR - 1) - 1 - 2

#ifndef DEBUG

#define FCS		2	/* First Connection Socket */

#define TRACE(x);

#else

#define FCS		4

#define TRACE(x)	printf x

#endif

/* descriptors when debugging:

 *  0 = server socket

 *  1 = standard output (debugging output)

 *  2 = standard error

 *  3 = syslog fd (hopefully -- otherwise this won't work)

 *  4 - 4 + MAXCONNS = connection sockets

 *

 * descriptors when not debugging

 *  0 = server socket

 *  1 = syslog fd (hopefully -- otherwise this won't work)

 *  2 = connection socket after detached from tty. standard error before that

 *  3 - 2 + MAXCONNS = rest connection sockets

 */

/*

 * FD of the connection is always the index of the connection structure

 * in `conns' array + FCS

 */

struct {

  char		buf[20];

  int		len;

  time_t	lasttime;

} conns[MAXCONNS];

/*

 * To support multible usernames that can be replied by this fake identd

 * define `XXXMULTI' in compilation command line. This doesn't look guite

 * pretty, but alternatives looks even uglier.

 * XXX NOTE: multi currently only slightly tested XXXX.

 */

#ifdef XXXMULTI

#define IU_IN_STRUCT char ** identuserlist; int identusers

#define SET_IU(s, c) do { G.identuserlist = &(s); G.identusers = c; } while (0)

#define IU_IN_USAGESTR "[identuser [identuser2...]]"

#else

#define IU_IN_STRUCT char * identuser

#define SET_IU(s, c) G.identuser = (s)

#define IU_IN_USAGESTR "[identuser]"

#endif

/* When using global variables, bind those at least to a structure. */

struct {

  IU_IN_STRUCT;

  fd_set	readfds;

  int		conncnt;

} G;

static const char rcs_id[] =

/* */ "$Id: identd.c,v 1.7 2002/09/29 07:50:20 too Stab $";

/*

 * Prototypes

 */

static void reply(int s, char * buf);

static void replyError(int s, char * buf);

static const char * strerrno(void);

const int one = 1;

char *	  nobodystr = "nobody";

/* a more general name would be `movefd',but we are only moving sockets here */

static inline void movesocket(int from, int to)

{

  TRACE(("movesocket(from = %d, to = %d)\n", from, to));

  dup2(from, to);

  close(from);

}

/*

 * inetbind() must always return 0 or value < 0.

 */

static int inetbind(int port)

{

  int			s;

  struct sockaddr_in	addr = { 0 };

  int			len = sizeof addr;

  close(0);

  if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0)

  {

      syslog(LOG_CRIT, "cannot create server socket: %s.", strerrno());

      return -1;

  }

  setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof one);

  addr.sin_family = AF_INET;

  addr.sin_port = htons(port);

  if (bind(s, (struct sockaddr *)&addr, len) < 0)

  {

      syslog(LOG_CRIT, "cannot bind() server socket: %s.", strerrno());

      return -1;

  }

  if (listen(s, 5) < 0)

  {

      syslog(LOG_CRIT, "cannot listen() server socket: %s.", strerrno());

      return -1;

  }

  if (s != 0)

  {

      movesocket(s, 0);

  }

  return 0;

}

static void deleteConn(int s)

{

  int i = s - FCS;

  TRACE(("deleteConn(): socket %d, conncnt %d\n", s, G.conncnt));

  close(s);

  G.conncnt--;

  /*

   * Most of the time there is 0 connections. Most often that there

   * is connections, there is just one connection. When this one connection

   * closes, i == G.conncnt = 0 -> no copying.

   * When there is more than one connection, the oldest connections closes

   * earlier on average. When this happens, the code below starts copying

   * the connection structure w/ highest index to the place which which is

   * just deleted. This means that the connection structures are no longer

   * in chronological order. I'd quess this means that when there is more

   * than 1 connection, on average every other connection structure needs

   * to be copied over the time all these connections are deleted.

   */

  if (i != G.conncnt)

  {

      memcpy(&conns[i], &conns[G.conncnt], sizeof conns[0]);

      movesocket(G.conncnt + FCS, s);

  }

  TRACE(("Clearing fd %d, readfds now 0x%x\n\n",

	 G.conncnt + FCS, *(int *)&G.readfds));

  FD_CLR(G.conncnt + FCS, &G.readfds);

}

static int closeOldest(void)

{

  time_t min = conns[0].lasttime;

  int	 idx = 0;

  int	 i;

  for (i = 1; i < MAXCONNS; i++)

  {

      if (conns[i].lasttime < min)

      {

	  idx = i;

      }

  }

  TRACE(("closeOldest(): index %d, socket %d\n", idx, idx + FCS));

  replyError(idx + FCS, "X-SERVER-TOO-BUSY");

  close(idx + FCS);

  return idx;

}

static inline int checkInput(char * buf, int len, int l)

{

  int	i;

  for (i = len; i < len + l; i++)

  {

      if (buf[i] == '\n')

      {

	  return 1;

      }

  }

  return 0;

}

static int getport(void)

{

  struct servent * se;

  if ((se = getservbyname("identd", "tcp")) == NULL)

  {

      return IDENT_PORT;

  }

  else

  {

      return se->s_port;

  }

}

static const char * strerrno()

{

  return sys_errlist[errno];

}

/* here we trust no-one in this program overflows our data buffer. */

static void fdprintf(int fd, char * format, ...)

{

  va_list	ap;

  char		buf[IDSTR_BUFLEN];

  va_start(ap, format);

  vsprintf(buf, format, ap);

  va_end(ap);

  write(fd, buf, strlen(buf));

}

#ifndef DEBUG

static void godaemon(void)

{

  switch(fork())

  {

  case -1:

    exit(-1);

  case 0:

    close(1);

    close(2);

    setsid();

    break;

  default:

    exit(0);

  }

}

#endif

#define PIDFILE "/var/run/identd.pid"

static void delpidfile(void)

{

  /*

   * Usually nobody has no write/delete access to directory /var/run/

   * therefore if file cannot be deleted, it is truncated

   */

  if (unlink(PIDFILE) < 0)

  {

      close(open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0644));

  }

}

static void handlexitsigs(void)

{

  delpidfile();

  exit(0);

}

static void writepid(uid_t nobody, uid_t nogrp)

     /* May succeed. If not, won't care. */

{

  int fd = open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0664);

  if (fd < 0)

  {

      return;

  }

  fdprintf(fd, "%d\n", getpid());

  fchown(fd, nobody, nogrp);

  close(fd);

  signal(SIGTERM, (void(*)(int))handlexitsigs);

  signal(SIGINT, (void(*)(int))handlexitsigs);

  signal(SIGQUIT, (void(*)(int))handlexitsigs);

  /* should this handle ILL, ... (see signal(7)) */

}

/* parses the `rcs_id' string for version information and prints the info. */

static void printversion(char nameterm)

{

  struct {

    const char * p;

    int		 l;

  } s[4] = { { 0 } };

  int		i;

  const char *	p;

  for (i = 0, p = rcs_id; *p && i < 4 ; i++)

  {

      while (*p != ' ' && *p != '\0')

      {

	  p++;

      }

      if (*p++ == ' ' && *p != '\0')

      {

	  s[i].p = p;

      }

  }

  if (s[0].p)

  {

      p = s[0].p;

      while (*p != nameterm && *p != ' ')

      {

	  p++;

      }

      s[0].l = p - s[0].p;

  }

  else

  {

      s[0].p = "unknown";

      s[0].l = 7;

  }

  for (i = 1; i < 3; i++)

  {

      if (s[i+1].p)

      {

	  s[i].l = s[i+1].p - s[i].p - 1;

      }

      else

      {

	  s[i].p = "unknown"; s[i].l = 7;

      }

  }

  fdprintf(1, "%.*s %.*s (%.*s)\n",

	   s[0].l, s[0].p, /**/ s[1].l, s[1].p, /**/ s[2].l, s[2].p);

}

int main(int argc, char * argv[])

{

  uid_t nobody, nogrp;

  memset(conns, 0, sizeof conns);

  memset(&G, 0, sizeof G);

  FD_ZERO(&G.readfds);

  FD_SET(0, &G.readfds);

  if (argv[1])

  {

      if (argv[1][0] == '-')

      {

	  if (argv[1][1] == 'V')

	  {

	      printversion('.');

	      return 0;

	  }

	  else

	  {

	      fdprintf(2, "%s: invalid option -- %c\n", argv[0], argv[1][1]);

	      fdprintf(2, "Usage: %s [-V] " IU_IN_USAGESTR "\n", argv[0]);

	      return 1;

	  }

      }

      else

      {

	  SET_IU(argv[1], argc - 1);

      }

  }

  else

  {

      SET_IU(nobodystr, 1);

  }

#ifndef DEBUG

  close(1); /* not debugging, openlog() hopefully uses fd 1. */

#else

  close(3); /* debugging, TRACE uses fd 1, openlog() hopefully fd 3 */

#endif

  openlog("identd", LOG_CONS, LOG_DAEMON);

  {

      struct passwd * pw = getpwnam(nobodystr);

      if (pw)

      {

	  nobody = pw->pw_uid;

	  nogrp = pw->pw_gid;

      }

      else

      {

	  syslog(LOG_CRIT, "Cannot find user `nobody': %s", strerrno());

	  return -1;

      }

  }

  if (inetbind(getport()) < 0)

  {

      return -1;

  }

  /* */

  {

      int			 i;

      for (i = FCS; i < MAXCONNS + FCS; i++)

      {

	  close(i);

      }

  }

#ifdef DEBUG

#ifndef LOG_PERROR

#define LOG_PERROR 0

#endif

  openlog("identd", LOG_PERROR, LOG_DAEMON);

#else /* not DEBUG */

  godaemon();

  openlog("identd", 0, LOG_DAEMON);

  close(2);

  signal(SIGHUP, SIG_IGN);

#endif /* DEBUG */

  signal(SIGPIPE, SIG_IGN); /* connection closed when writing (raises ???) */

  writepid(nobody, nogrp);

  setegid(nogrp); setgid(nogrp); setuid(nobody); seteuid(nobody);

  {

      int i;

      for (i = 0; i < 4; i++)

      {

	  char *	id = (char)NULL;

	  unsigned int	rv = 0;

	  switch (i)

	  {

	  case 0:

	    rv = (unsigned int)getegid();

	    id = "egid";

	    break;

	  case 1:

	    rv = (unsigned int)getgid();

	    id = "gid";

	    break;

	  case 2:

	    rv = (unsigned int)geteuid();

	    id = "euid";

	    break;

	  case 3:

	    rv = (unsigned int)getuid();

	    id = "uid";

	    break;

	  }

	  if (rv == 0)

	  {

	      syslog(LOG_ERR,

		     "Can not drop all root privileges (%s) !!! %s !!!",

		     id, strerrno());

	      delpidfile();

	      return -1;

	  }

      }

  }

  while (2)

  {

      fd_set		rfds = G.readfds;

      struct timeval	tv = { 15, 0 };

      int		i;

      int		tim = time(NULL);

      TRACE(("calling select(): n = %d, rfds = 0x%x\n\n",

	     G.conncnt + FCS, *(int *)&rfds));

      select(G.conncnt + FCS, &rfds, NULL, NULL, G.conncnt? &tv: NULL);

      for (i = G.conncnt - 1; i >= 0; i--)

      {

	  int s = i + FCS;

	  if (FD_ISSET(s, &rfds))

	  {

	      char *		buf = conns[i].buf;

	      unsigned int	len = conns[i].len;

	      unsigned int	l;

	      TRACE(("data socket fd_isset %d\n", s));

	      if ((int)(l = read(s, buf + len, sizeof conns[0].buf - len)) > 0)

	      {

		  if (checkInput(buf, len, l))

		  {

		      reply(s, buf);

		      goto deleteconn;

		  }

		  else if (len + l >= sizeof conns[0].buf)

		  {

		      replyError(s, "X-INVALID-REQUEST");

		      goto deleteconn;

		  }

		  else

		  {

		      conns[i].len += l;

		  }

	      }

	      else

	      {

		  goto deleteconn;

	      }

	      conns[i].lasttime = tim;

	      continue;

	  deleteconn:

	      deleteConn(s);

	  }

	  else

	  {

	      /* implement as time_after() in linux kernel sources ... */

	      if (conns[i].lasttime + MAXIDLETIME <= tim)

	      {

		  replyError(s, "X-TIMEOUT");

		  deleteConn(s);

	      }

	  }

      }

      if (FD_ISSET(0, &rfds))

      {

	  int s = accept(0, NULL, 0);

	  TRACE(("server socket fd_isset, %d accepted\n", s));

	  if (s < 0)

	  {

	      if (errno != EINTR) /* EINTR */

	      {

		  syslog(LOG_ERR, "accept: %s", strerrno());

	      }

	  }

	  else

	  {

	      if (G.conncnt == MAXCONNS)

	      {

		  i = closeOldest();

	      }

	      else

	      {

		  i = G.conncnt++;

	      }

	      if (s != i + FCS)

	      {

		  movesocket(s, i + FCS);

	      }

	      FD_SET(i + FCS, &G.readfds);

	      conns[i].len = 0;

	      conns[i].lasttime = time(NULL);

	  }

      }

  }

}

static int parseAddrs(char * ptr, int * myaddr, int * heraddr);

static void replyError(int s, char * buf)

{

  fdprintf(s, "0, 0 : ERROR : %s\r\n", buf);

}

static void reply(int s, char * buf)

{

  int myaddr, heraddr;

  myaddr = heraddr = 0;

  if (parseAddrs(buf, &myaddr, &heraddr))

  {

      replyError(s, "X-INVALID-REQUEST");

  }

  else

  {

      fdprintf(s, "%d, %d " IDENT_SUBSTR " %.*s\r\n",

	       myaddr, heraddr, IDSTR_MAX,

#ifdef XXXMULTI

	       G.identuserlist[random() % G.identusers]

#else

       	       G.identuser

#endif

	       );

  }

}

static int chmatch(char c, char * chars)

{

  while (*chars)

  {

    if (c == *chars)

    {

	return 1;

    }

    else

    {

	chars++;

    }

  }

  return 0;

}

static int skipchars(char ** p, char * chars)

{

  while (chmatch(**p, chars))

  {

      (*p)++;

  }

  if (**p == '\r' || **p == '\n')

  {

      return -1;

  }

  return 0;

}

static int parseAddrs(char * ptr, int * myaddr, int * heraddr)

{

  /* parse <port-on-server> , <port-on-client> */

  if (skipchars(&ptr, " \t") ||

      (*myaddr = atoi(ptr)) <= 0 ||

      skipchars(&ptr, "1234567890") ||

      skipchars(&ptr, " \t,") ||

      (*heraddr = atoi(ptr)) <= 0)

  {

      return -1;

  }

  return 0;

}

/*

 * Variables for Emacs

 *

 * Local variables:

 * mode: c

 * c-file-style: "gnu"

 * c-file-offsets: ( (substatement-open . 0) (statement-block-intro . ++) )

 * tab-width: 8

 * compile-command: "sh identd.c"

 * End:

 */

/* EOF */

To enable fakeidentd please add fakeidentd_enable="YES" to

/etc/rc.conf.