/*

 * purple

 *

 * Purple is the legal property of its developers, whose names are too numerous

 * to list here.  Please refer to the COPYRIGHT file distributed with this

 * source distribution.

 *

 * Original md4 taken from linux kernel

 * MD4 Message Digest Algorithm (RFC1320).

 *

 * Implementation derived from Andrew Tridgell and Steve French's

 * CIFS MD4 implementation, and the cryptoapi implementation

 * originally based on the public domain implementation written

 * by Colin Plumb in 1993.

 *

 * Copyright (c) Andrew Tridgell 1997-1998.

 * Modified by Steve French (sfrench@us.ibm.com) 2002

 * Copyright (c) Cryptoapi developers.

 * Copyright (c) 2002 David S. Miller (davem@redhat.com)

 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>

 *

 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02111-1301  USA

 */

#include <cipher.h>

#define MD4_DIGEST_SIZE     16

#define MD4_HMAC_BLOCK_SIZE 64

#define MD4_BLOCK_WORDS     16

#define MD4_HASH_WORDS      4

struct MD4_Context {

  guint32 hash[MD4_HASH_WORDS];

  guint32 block[MD4_BLOCK_WORDS];

  guint64 byte_count;

};

static inline guint32 lshift(guint32 x, unsigned int s)

{

  x &= 0xFFFFFFFF;

  return ((x << s) & 0xFFFFFFFF) | (x >> (32 - s));

}

static inline guint32 F(guint32 x, guint32 y, guint32 z)

{

  return (x & y) | ((~x) & z);

}

static inline guint32 G(guint32 x, guint32 y, guint32 z)

{

  return (x & y) | (x & z) | (y & z);

}

static inline guint32 H(guint32 x, guint32 y, guint32 z)

{

  return x ^ y ^ z;

}

#define ROUND1(a,b,c,d,k,s) (a = lshift(a + F(b,c,d) + k, s))

#define ROUND2(a,b,c,d,k,s) (a = lshift(a + G(b,c,d) + k + (guint32)0x5A827999,s))

#define ROUND3(a,b,c,d,k,s) (a = lshift(a + H(b,c,d) + k + (guint32)0x6ED9EBA1,s))

static inline void le32_to_cpu_array(guint32 *buf, unsigned int words)

{

  while (words--) {

    *buf=GUINT_FROM_LE(*buf);

    buf++;

  }

}

static inline void cpu_to_le32_array(guint32 *buf, unsigned int words)

{

  while (words--) {

    *buf=GUINT_TO_LE(*buf);

    buf++;

  }

}

static void md4_transform(guint32 *hash, guint32 const *in)

{

  guint32 a, b, c, d;

  a = hash[0];

  b = hash[1];

  c = hash[2];

  d = hash[3];

  ROUND1(a, b, c, d, in[0], 3);

  ROUND1(d, a, b, c, in[1], 7);

  ROUND1(c, d, a, b, in[2], 11);

  ROUND1(b, c, d, a, in[3], 19);

  ROUND1(a, b, c, d, in[4], 3);

  ROUND1(d, a, b, c, in[5], 7);

  ROUND1(c, d, a, b, in[6], 11);

  ROUND1(b, c, d, a, in[7], 19);

  ROUND1(a, b, c, d, in[8], 3);

  ROUND1(d, a, b, c, in[9], 7);

  ROUND1(c, d, a, b, in[10], 11);

  ROUND1(b, c, d, a, in[11], 19);

  ROUND1(a, b, c, d, in[12], 3);

  ROUND1(d, a, b, c, in[13], 7);

  ROUND1(c, d, a, b, in[14], 11);

  ROUND1(b, c, d, a, in[15], 19);

  ROUND2(a, b, c, d,in[ 0], 3);

  ROUND2(d, a, b, c, in[4], 5);

  ROUND2(c, d, a, b, in[8], 9);

  ROUND2(b, c, d, a, in[12], 13);

  ROUND2(a, b, c, d, in[1], 3);

  ROUND2(d, a, b, c, in[5], 5);

  ROUND2(c, d, a, b, in[9], 9);

  ROUND2(b, c, d, a, in[13], 13);

  ROUND2(a, b, c, d, in[2], 3);

  ROUND2(d, a, b, c, in[6], 5);

  ROUND2(c, d, a, b, in[10], 9);

  ROUND2(b, c, d, a, in[14], 13);

  ROUND2(a, b, c, d, in[3], 3);

  ROUND2(d, a, b, c, in[7], 5);

  ROUND2(c, d, a, b, in[11], 9);

  ROUND2(b, c, d, a, in[15], 13);

  ROUND3(a, b, c, d,in[ 0], 3);

  ROUND3(d, a, b, c, in[8], 9);

  ROUND3(c, d, a, b, in[4], 11);

  ROUND3(b, c, d, a, in[12], 15);

  ROUND3(a, b, c, d, in[2], 3);

  ROUND3(d, a, b, c, in[10], 9);

  ROUND3(c, d, a, b, in[6], 11);

  ROUND3(b, c, d, a, in[14], 15);

  ROUND3(a, b, c, d, in[1], 3);

  ROUND3(d, a, b, c, in[9], 9);

  ROUND3(c, d, a, b, in[5], 11);

  ROUND3(b, c, d, a, in[13], 15);

  ROUND3(a, b, c, d, in[3], 3);

  ROUND3(d, a, b, c, in[11], 9);

  ROUND3(c, d, a, b, in[7], 11);

  ROUND3(b, c, d, a, in[15], 15);

  hash[0] += a;

  hash[1] += b;

  hash[2] += c;

  hash[3] += d;

}

static inline void md4_transform_helper(struct MD4_Context *ctx)

{

  le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(guint32));

  md4_transform(ctx->hash, ctx->block);

}

static void

md4_init(PurpleCipherContext *context, gpointer extra) {

  struct MD4_Context *mctx;

  mctx = g_new0(struct MD4_Context, 1);

  purple_cipher_context_set_data(context, mctx);

  purple_cipher_context_reset(context, extra);

  mctx->hash[0] = 0x67452301;

  mctx->hash[1] = 0xefcdab89;

  mctx->hash[2] = 0x98badcfe;

  mctx->hash[3] = 0x10325476;

  mctx->byte_count = 0;

}

static void

md4_reset(PurpleCipherContext *context, gpointer extra) {

  struct MD4_Context *mctx;

  mctx = purple_cipher_context_get_data(context);

  mctx->hash[0] = 0x67452301;

  mctx->hash[1] = 0xefcdab89;

  mctx->hash[2] = 0x98badcfe;

  mctx->hash[3] = 0x10325476;

  mctx->byte_count = 0;

}

  static void

md4_append(PurpleCipherContext *context, const guchar *data, size_t len)

{

  struct MD4_Context *mctx = purple_cipher_context_get_data(context);

  const guint32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);

  mctx->byte_count += len;

  if (avail > len) {

    memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),

        data, len);

    return;

  }

  memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),

      data, avail);

  md4_transform_helper(mctx);

  data += avail;

  len -= avail;

  while (len >= sizeof(mctx->block)) {

    memcpy(mctx->block, data, sizeof(mctx->block));

    md4_transform_helper(mctx);

    data += sizeof(mctx->block);

    len -= sizeof(mctx->block);

  }

  memcpy(mctx->block, data, len);

}

  static gboolean

md4_digest(PurpleCipherContext *context, size_t in_len, guchar *out,

    size_t *out_len)

{

  struct MD4_Context *mctx = purple_cipher_context_get_data(context);

  const unsigned int offset = mctx->byte_count & 0x3f;

  char *p = (char *)mctx->block + offset;

  int padding = 56 - (offset + 1);

  if(in_len<16) return FALSE;

  if(out_len) *out_len = 16;

  *p++ = 0x80;

  if (padding < 0) {

    memset(p, 0x00, padding + sizeof (guint64));

    md4_transform_helper(mctx);

    p = (char *)mctx->block;

    padding = 56;

  }

  memset(p, 0, padding);

  mctx->block[14] = mctx->byte_count << 3;

  mctx->block[15] = mctx->byte_count >> 29;

  le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -

        sizeof(guint64)) / sizeof(guint32));

  md4_transform(mctx->hash, mctx->block);

  cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(guint32));

  memcpy(out, mctx->hash, sizeof(mctx->hash));

  memset(mctx, 0, sizeof(*mctx));

  return TRUE;

}

static void

md4_uninit(PurpleCipherContext *context) {

  struct MD4_Context *md4_context;

  purple_cipher_context_reset(context, NULL);

  md4_context = purple_cipher_context_get_data(context);

  memset(md4_context, 0, sizeof(*md4_context));

  g_free(md4_context);

  md4_context = NULL;

}

  static size_t

md4_get_block_size(PurpleCipherContext *context)

{

  /* This does not change (in this case) */

  return MD4_HMAC_BLOCK_SIZE;

}

static PurpleCipherOps MD4Ops = {

  NULL,                   /* Set option */

  NULL,                   /* Get option */

  md4_init,               /* init */

  md4_reset,              /* reset */

  md4_uninit,             /* uninit */

  NULL,                   /* set iv */

  md4_append,             /* append */

  md4_digest,             /* digest */

  NULL,                   /* encrypt */

  NULL,                   /* decrypt */

  NULL,                   /* set salt */

  NULL,                   /* get salt size */

  NULL,                   /* set key */

  NULL,                   /* get key size */

  NULL,                   /* set batch mode */

  NULL,                   /* get batch mode */

  md4_get_block_size,     /* get block size */

  NULL                    /* set key with len */

};

PurpleCipherOps *

purple_md4_cipher_get_ops(void) {

  return &MD4Ops;

}