/*

     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/module.h>

  #include <linux/slab.h>

  #include <linux/fs.h>
  #include <linux/string.h>
  #include <linux/kernel.h>
  #include <linux/random.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_blkcipher *tfm_des;
  	struct scatterlist sgin, sgout;
  	struct blkcipher_desc desc;
  
  	str_to_key(key, key2);
  
  	tfm_des = crypto_alloc_blkcipher("ecb(des)", 0, CRYPTO_ALG_ASYNC);
  	if (IS_ERR(tfm_des)) {
  		rc = PTR_ERR(tfm_des);
  		cERROR(1, "could not allocate des crypto API
  ");
  		goto smbhash_err;
  	}
  
  	desc.tfm = tfm_des;
  
  	crypto_blkcipher_setkey(tfm_des, key2, 8);
  
  	sg_init_one(&sgin, in, 8);
  	sg_init_one(&sgout, out, 8);
  
  	rc = crypto_blkcipher_encrypt(&desc, &sgout, &sgin, 8);

  	if (rc)

  		cERROR(1, "could not encrypt crypt key rc: %d
  ", rc);

  	crypto_free_blkcipher(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);

  		cERROR(1, "%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;
  		cERROR(1, "%s: Memory allocation failure
  ", __func__);
  		goto mdfour_err;
  	}
  	sdescmd4->shash.tfm = md4;
  	sdescmd4->shash.flags = 0x0;
  
  	rc = crypto_shash_init(&sdescmd4->shash);
  	if (rc) {
  		cERROR(1, "%s: Could not init md4 shash
  ", __func__);
  		goto mdfour_err;
  	}

  	rc = crypto_shash_update(&sdescmd4->shash, link_str, link_len);
  	if (rc) {
  		cERROR(1, "%s: Could not update with link_str
  ", __func__);
  		goto mdfour_err;
  	}

  	rc = crypto_shash_final(&sdescmd4->shash, md4_hash);

  	if (rc)
  		cERROR(1, "%s: Could not genereate 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;

  }
  
  /* Routines for Windows NT MD4 Hash functions. */
  static int

  _my_wcslen(__u16 *str)

  {
  	int len = 0;
  	while (*str++ != 0)
  		len++;
  	return len;
  }
  
  /*
   * Convert a string into an NT UNICODE string.

   * Note that regardless of processor type

   * this must be in intel (little-endian)
   * format.
   */
  
  static int

  _my_mbstowcs(__u16 *dst, const unsigned char *src, int len)

  {	/* BB not a very good conversion routine - change/fix */

  	int i;
  	__u16 val;
  
  	for (i = 0; i < len; i++) {
  		val = *src;
  		SSVAL(dst, 0, val);
  		dst++;
  		src++;
  		if (val == 0)
  			break;
  	}
  	return i;
  }

  /*

   * Creates the MD4 Hash of the users password in NT UNICODE.
   */

  int

  E_md4hash(const unsigned char *passwd, unsigned char *p16)
  {

  	int rc;

  	int len;
  	__u16 wpwd[129];
  
  	/* Password cannot be longer than 128 characters */

  	if (passwd) {

  		len = strlen((char *) passwd);

  		if (len > 128)

  			len = 128;

  		/* Password must be converted to NT unicode */
  		_my_mbstowcs(wpwd, passwd, len);
  	} else
  		len = 0;
  
  	wpwd[len] = 0;	/* Ensure string is null terminated */
  	/* Calculate length in bytes */

  	len = _my_wcslen(wpwd) * sizeof(__u16);

  	rc = mdfour(p16, (unsigned char *) wpwd, len);

  	memset(wpwd, 0, 129 * 2);

  
  	return rc;

  }

  #if 0 /* currently unused */

  /* Does both the NT and LM owfs of a user's password */

  static void

  nt_lm_owf_gen(char *pwd, unsigned char nt_p16[16], unsigned char p16[16])
  {
  	char passwd[514];
  
  	memset(passwd, '\0', 514);
  	if (strlen(pwd) < 513)
  		strcpy(passwd, pwd);
  	else
  		memcpy(passwd, pwd, 512);
  	/* Calculate the MD4 hash (NT compatible) of the password */
  	memset(nt_p16, '\0', 16);
  	E_md4hash(passwd, nt_p16);
  
  	/* Mangle the passwords into Lanman format */
  	passwd[14] = '\0';
  /*	strupper(passwd); */
  
  	/* Calculate the SMB (lanman) hash functions of the password */
  
  	memset(p16, '\0', 16);
  	E_P16((unsigned char *) passwd, (unsigned char *) p16);
  
  	/* clear out local copy of user's password (just being paranoid). */

  	memset(passwd, '\0', sizeof(passwd));

  }

  #endif

  
  /* Does the NTLMv2 owfs of a user's password */
  #if 0  /* function not needed yet - but will be soon */
  static void
  ntv2_owf_gen(const unsigned char owf[16], const char *user_n,
  		const char *domain_n, unsigned char kr_buf[16],
  		const struct nls_table *nls_codepage)
  {

  	wchar_t *user_u;
  	wchar_t *dom_u;

  	int user_l, domain_l;
  	struct HMACMD5Context ctx;
  
  	/* might as well do one alloc to hold both (user_u and dom_u) */

  	user_u = kmalloc(2048 * sizeof(wchar_t), GFP_KERNEL);
  	if (user_u == NULL)

  		return;
  	dom_u = user_u + 1024;

  	/* push_ucs2(NULL, user_u, user_n, (user_l+1)*2,
  			STR_UNICODE|STR_NOALIGN|STR_TERMINATE|STR_UPPER);
  	   push_ucs2(NULL, dom_u, domain_n, (domain_l+1)*2,
  			STR_UNICODE|STR_NOALIGN|STR_TERMINATE|STR_UPPER); */

  
  	/* BB user and domain may need to be uppercased */
  	user_l = cifs_strtoUCS(user_u, user_n, 511, nls_codepage);
  	domain_l = cifs_strtoUCS(dom_u, domain_n, 511, nls_codepage);
  
  	user_l++;		/* trailing null */
  	domain_l++;
  
  	hmac_md5_init_limK_to_64(owf, 16, &ctx);
  	hmac_md5_update((const unsigned char *) user_u, user_l * 2, &ctx);
  	hmac_md5_update((const unsigned char *) dom_u, domain_l * 2, &ctx);
  	hmac_md5_final(kr_buf, &ctx);
  
  	kfree(user_u);
  }

  #endif

  /* Does the des encryption from the FIRST 8 BYTES of the NT or LM MD4 hash. */

  #if 0 /* currently unused */

  static void

  NTLMSSPOWFencrypt(unsigned char passwd[8],
  		  unsigned char *ntlmchalresp, unsigned char p24[24])
  {
  	unsigned char p21[21];
  
  	memset(p21, '\0', 21);
  	memcpy(p21, passwd, 8);
  	memset(p21 + 8, 0xbd, 8);
  
  	E_P24(p21, ntlmchalresp, p24);
  }

  #endif

  
  /* Does the NT MD4 hash then des encryption. */

  int

  SMBNTencrypt(unsigned char *passwd, unsigned char *c8, unsigned char *p24)
  {

  	int rc;

  	unsigned char p16[16], p21[21];

  	memset(p16, '\0', 16);

  	memset(p21, '\0', 21);

  	rc = E_md4hash(passwd, p16);

  	if (rc) {
  		cFYI(1, "%s Can't generate NT hash, error: %d", __func__, rc);
  		return rc;
  	}

  	memcpy(p21, p16, 16);
  	rc = E_P24(p21, c8, p24);

  	return rc;

  }
  
  
  /* Does the md5 encryption from the NT hash for NTLMv2. */
  /* These routines will be needed later */
  #if 0
  static void
  SMBOWFencrypt_ntv2(const unsigned char kr[16],

  		   const struct data_blob *srv_chal,
  		   const struct data_blob *cli_chal, unsigned char resp_buf[16])

  {

  	struct HMACMD5Context ctx;

  	hmac_md5_init_limK_to_64(kr, 16, &ctx);
  	hmac_md5_update(srv_chal->data, srv_chal->length, &ctx);
  	hmac_md5_update(cli_chal->data, cli_chal->length, &ctx);
  	hmac_md5_final(resp_buf, &ctx);

  }
  
  static void
  SMBsesskeygen_ntv2(const unsigned char kr[16],
  		   const unsigned char *nt_resp, __u8 sess_key[16])
  {
  	struct HMACMD5Context ctx;
  
  	hmac_md5_init_limK_to_64(kr, 16, &ctx);
  	hmac_md5_update(nt_resp, 16, &ctx);
  	hmac_md5_final((unsigned char *) sess_key, &ctx);
  }
  
  static void
  SMBsesskeygen_ntv1(const unsigned char kr[16],
  		   const unsigned char *nt_resp, __u8 sess_key[16])
  {
  	mdfour((unsigned char *) sess_key, (unsigned char *) kr, 16);
  }
  #endif