/*
 * Copyright © 2005 Atheme Development Group
 * Rights to this code are as documented in doc/pod/license.pod.
 *
 * IRCServices's weird password encryption thingy, taken from Anope 1.6.3.
 *
 * $Id: ircservices.C,v 1.2 2007/07/21 01:29:09 pippijn Exp $
 */
/* Include file for high-level encryption routines.
 *
 * (C) 2003 Anope Team
 * Contact us at info@anope.org
 *
 * Please read COPYING and README for furhter details.
 *
 * Based on the original code of Epona by Lara.
 * Based on the original code of Services by Andy Church. 
 * 
 * $\Id: myencrypt.c 5 2004-03-29 01:29:50Z dane $ 
 *
 */

#include "atheme.h"

/* necessary anope defines */
#define PASSMAX 32
#define ENCRYPT_MD5 1

/*************************************************************************/

/******** Our own high-level routines. ********/


#define XTOI(c) ((c)>9 ? (c)-'A'+10 : (c)-'0')
/* Result of this:
 * c in [-128,9]  =>  [-183,-46]
 * c in [10,127]  =>  [-38,79]
 */

/* Encrypt `src' of length `len' and store the result in `dest'.  If the
 * resulting string would be longer than `size', return -1 and leave `dest'
 * unchanged; else return 0.
 */
static int
myencrypt (const char *src, int len, char *dest, int size)
{
#if ENCRYPT_MD5
  MD5Context context;
  char digest[33];
  char dest2[16];
  int i;

  if (size < 32)
    return -1;

  memset (&context, 0, sizeof (context));
  memset (&digest, 0, sizeof (digest));

  MD5Init (&context);
  MD5Update (&context, (unsigned char const *) src, (size_t) len);
  MD5Final ((unsigned char *) digest, &context);

  for (i = 0; i < 32; i += 2)
    dest2[i / 2] = XTOI (digest[i]) << 4 | XTOI (digest[i + 1]);

  /* convert to hex, skipping last 8 bytes (constant) -- jilles */
  strcpy (dest, "$ircservices$");
  for (i = 0; i <= 7; i++)
    sprintf (dest + 13 + 2 * i, "%02x", 255 & dest2[i]);
  return 0;

#endif

  return -1;			/* unknown encryption algorithm */
}

#if 0				/* unused */
/* Shortcut for encrypting a null-terminated string in place. */
static int
encrypt_in_place (char *buf, int size)
{
  return myencrypt (buf, strlen (buf), buf, size);
}
#endif

/* Compare a plaintext string against an encrypted password.  Return 1 if
 * they match, 0 if not, and -1 if something went wrong. */

static int
check_password (const char *plaintext, const char *password)
{
  char buf[BUFSIZE];

  if (myencrypt (plaintext, strlen (plaintext), buf, sizeof (buf)) < 0)
    return -1;
#ifdef ENCRYPT_MD5
  if (strcmp (buf, password) == 0)
#else
  if (0)
#endif
    return 1;
  else
    return 0;
}

/*************************************************************************/

static char const rcsid[] = "$Id";

struct crypto_ircservices_listeners : callback::has_listeners
{
};

crypto_ircservices_listeners listeners;

DECLARE_MODULE_V1 ("crypto/ircservices", false, _modinit, _moddeinit, "$Id: ircservices.C,v 1.2 2007/07/21 01:29:09 pippijn Exp $", "Jilles Tjoelker <jilles@stack.nl>");

static char *
ircservices_crypt_string (char *key, char *salt)
{
  static char output[PASSMAX];
  if (salt[0] == '$' && salt[1] == '1')	/* this is a new pw XXX */
    {
      myencrypt (key, strlen (key), output, PASSMAX);
      return output;
    }
  else
    {
      if (check_password (key, salt))
	return salt;
      else
	return "";
    }
}

void
_modinit (module_t *m)
{
  crypt_string = &ircservices_crypt_string;

  crypto_module_loaded = true;
}

void
_moddeinit (void)
{
  crypt_string = &generic_crypt_string;

  crypto_module_loaded = false;
}

/* vim:cinoptions=>s,e0,n0,f0,{0,}0,^0,=s,ps,t0,c3,+s,(2s,us,)20,*30,gs,hs
 * vim:ts=8
 * vim:sw=8
 * vim:noexpandtab
 */