/*

     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 <crypto/skcipher.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)
  {
  	int rc;
  	unsigned char key2[8];

  	struct crypto_skcipher *tfm_des;

  	struct scatterlist sgin, sgout;

  	struct skcipher_request *req;

  
  	str_to_key(key, key2);

  	tfm_des = crypto_alloc_skcipher("ecb(des)", 0, CRYPTO_ALG_ASYNC);

  	if (IS_ERR(tfm_des)) {
  		rc = PTR_ERR(tfm_des);

  		cifs_dbg(VFS, "could not allocate des crypto API
  ");

  		goto smbhash_err;
  	}

  	req = skcipher_request_alloc(tfm_des, GFP_KERNEL);
  	if (!req) {
  		rc = -ENOMEM;
  		cifs_dbg(VFS, "could not allocate des crypto API
  ");
  		goto smbhash_free_skcipher;
  	}

  	crypto_skcipher_setkey(tfm_des, key2, 8);

  
  	sg_init_one(&sgin, in, 8);
  	sg_init_one(&sgout, out, 8);

  	skcipher_request_set_callback(req, 0, NULL, NULL);
  	skcipher_request_set_crypt(req, &sgin, &sgout, 8, NULL);
  
  	rc = crypto_skcipher_encrypt(req);

  	if (rc)

  		cifs_dbg(VFS, "could not encrypt crypt key rc: %d
  ", rc);

  	skcipher_request_free(req);
  
  smbhash_free_skcipher:
  	crypto_free_skcipher(tfm_des);

  smbhash_err:
  	return rc;
  }
  
  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;
  	unsigned int size;
  	struct crypto_shash *md4;
  	struct sdesc *sdescmd4;
  
  	md4 = crypto_alloc_shash("md4", 0, 0);
  	if (IS_ERR(md4)) {

  		rc = PTR_ERR(md4);

  		cifs_dbg(VFS, "%s: Crypto md4 allocation error %d
  ",
  			 __func__, rc);

  		return rc;

  	}
  	size = sizeof(struct shash_desc) + crypto_shash_descsize(md4);
  	sdescmd4 = kmalloc(size, GFP_KERNEL);
  	if (!sdescmd4) {
  		rc = -ENOMEM;

  		goto mdfour_err;
  	}
  	sdescmd4->shash.tfm = md4;
  	sdescmd4->shash.flags = 0x0;
  
  	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:
  	crypto_free_shash(md4);
  	kfree(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;

  }