/*
     Unix SMB/Netbios implementation.
     Version 1.9.
     SMB parameters and setup
     Copyright (C) Andrew Tridgell 1992-2000
     Copyright (C) Luke Kenneth Casson Leighton 1996-2000
     Modified by Jeremy Allison 1995.
     Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003
     Modified by Steve French (sfrench@us.ibm.com) 2002-2003
  
     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.
  */
  
  #include <linux/crypto.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/fs.h>
  #include <linux/string.h>
  #include <linux/kernel.h>
  #include <linux/random.h>
  #include "cifs_fs_sb.h"
  #include "cifs_unicode.h"
  #include "cifspdu.h"
  #include "cifsglob.h"
  #include "cifs_debug.h"
  #include "cifsproto.h"
  
  #ifndef false
  #define false 0
  #endif
  #ifndef true
  #define true 1
  #endif
  
  /* following came from the other byteorder.h to avoid include conflicts */
  #define CVAL(buf,pos) (((unsigned char *)(buf))[pos])
  #define SSVALX(buf,pos,val) (CVAL(buf,pos)=(val)&0xFF,CVAL(buf,pos+1)=(val)>>8)
  #define SSVAL(buf,pos,val) SSVALX((buf),(pos),((__u16)(val)))
  
  static void
  str_to_key(unsigned char *str, unsigned char *key)
  {
  	int i;
  
  	key[0] = str[0] >> 1;
  	key[1] = ((str[0] & 0x01) << 6) | (str[1] >> 2);
  	key[2] = ((str[1] & 0x03) << 5) | (str[2] >> 3);
  	key[3] = ((str[2] & 0x07) << 4) | (str[3] >> 4);
  	key[4] = ((str[3] & 0x0F) << 3) | (str[4] >> 5);
  	key[5] = ((str[4] & 0x1F) << 2) | (str[5] >> 6);
  	key[6] = ((str[5] & 0x3F) << 1) | (str[6] >> 7);
  	key[7] = str[6] & 0x7F;
  	for (i = 0; i < 8; i++)
  		key[i] = (key[i] << 1);
  }
  
  static int
  smbhash(unsigned char *out, const unsigned char *in, unsigned char *key)
  {
  	unsigned char key2[8];
  	struct crypto_cipher *tfm_des;
  
  	str_to_key(key, key2);
  
  	tfm_des = crypto_alloc_cipher("des", 0, 0);
  	if (IS_ERR(tfm_des)) {
  		cifs_dbg(VFS, "could not allocate des crypto API
  ");
  		return PTR_ERR(tfm_des);
  	}
  
  	crypto_cipher_setkey(tfm_des, key2, 8);
  	crypto_cipher_encrypt_one(tfm_des, out, in);
  	crypto_free_cipher(tfm_des);
  
  	return 0;
  }
  
  static int
  E_P16(unsigned char *p14, unsigned char *p16)
  {
  	int rc;
  	unsigned char sp8[8] =
  	    { 0x4b, 0x47, 0x53, 0x21, 0x40, 0x23, 0x24, 0x25 };
  
  	rc = smbhash(p16, sp8, p14);
  	if (rc)
  		return rc;
  	rc = smbhash(p16 + 8, sp8, p14 + 7);
  	return rc;
  }
  
  static int
  E_P24(unsigned char *p21, const unsigned char *c8, unsigned char *p24)
  {
  	int rc;
  
  	rc = smbhash(p24, c8, p21);
  	if (rc)
  		return rc;
  	rc = smbhash(p24 + 8, c8, p21 + 7);
  	if (rc)
  		return rc;
  	rc = smbhash(p24 + 16, c8, p21 + 14);
  	return rc;
  }
  
  /* produce a md4 message digest from data of length n bytes */
  int
  mdfour(unsigned char *md4_hash, unsigned char *link_str, int link_len)
  {
  	int rc;
  	struct crypto_shash *md4 = NULL;
  	struct sdesc *sdescmd4 = NULL;
  
  	rc = cifs_alloc_hash("md4", &md4, &sdescmd4);
  	if (rc)
  		goto mdfour_err;
  
  	rc = crypto_shash_init(&sdescmd4->shash);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not init md4 shash
  ", __func__);
  		goto mdfour_err;
  	}
  	rc = crypto_shash_update(&sdescmd4->shash, link_str, link_len);
  	if (rc) {
  		cifs_dbg(VFS, "%s: Could not update with link_str
  ", __func__);
  		goto mdfour_err;
  	}
  	rc = crypto_shash_final(&sdescmd4->shash, md4_hash);
  	if (rc)
  		cifs_dbg(VFS, "%s: Could not generate md4 hash
  ", __func__);
  
  mdfour_err:
  	cifs_free_hash(&md4, &sdescmd4);
  	return rc;
  }
  
  /*
     This implements the X/Open SMB password encryption
     It takes a password, a 8 byte "crypt key" and puts 24 bytes of
     encrypted password into p24 */
  /* Note that password must be uppercased and null terminated */
  int
  SMBencrypt(unsigned char *passwd, const unsigned char *c8, unsigned char *p24)
  {
  	int rc;
  	unsigned char p14[14], p16[16], p21[21];
  
  	memset(p14, '\0', 14);
  	memset(p16, '\0', 16);
  	memset(p21, '\0', 21);
  
  	memcpy(p14, passwd, 14);
  	rc = E_P16(p14, p16);
  	if (rc)
  		return rc;
  
  	memcpy(p21, p16, 16);
  	rc = E_P24(p21, c8, p24);
  
  	return rc;
  }
  
  /*
   * Creates the MD4 Hash of the users password in NT UNICODE.
   */
  
  int
  E_md4hash(const unsigned char *passwd, unsigned char *p16,
  	const struct nls_table *codepage)
  {
  	int rc;
  	int len;
  	__le16 wpwd[129];
  
  	/* Password cannot be longer than 128 characters */
  	if (passwd) /* Password must be converted to NT unicode */
  		len = cifs_strtoUTF16(wpwd, passwd, 128, codepage);
  	else {
  		len = 0;
  		*wpwd = 0; /* Ensure string is null terminated */
  	}
  
  	rc = mdfour(p16, (unsigned char *) wpwd, len * sizeof(__le16));
  	memzero_explicit(wpwd, sizeof(wpwd));
  
  	return rc;
  }
  
  /* Does the NT MD4 hash then des encryption. */
  int
  SMBNTencrypt(unsigned char *passwd, unsigned char *c8, unsigned char *p24,
  		const struct nls_table *codepage)
  {
  	int rc;
  	unsigned char p16[16], p21[21];
  
  	memset(p16, '\0', 16);
  	memset(p21, '\0', 21);
  
  	rc = E_md4hash(passwd, p16, codepage);
  	if (rc) {
  		cifs_dbg(FYI, "%s Can't generate NT hash, error: %d
  ",
  			 __func__, rc);
  		return rc;
  	}
  	memcpy(p21, p16, 16);
  	rc = E_P24(p21, c8, p24);
  	return rc;
  }