/**
 * Author......: See docs/credits.txt
 * License.....: MIT
 */

//shared mem too small
//#define NEW_SIMD_CODE

#ifdef KERNEL_STATIC
#include "inc_vendor.h"
#include "inc_types.h"
#include "inc_platform.cl"
#include "inc_common.cl"
#include "inc_hash_md4.cl"
#include "inc_hash_md5.cl"
#include "inc_cipher_rc4.cl"
#endif

typedef struct krb5asrep
{
  u32 account_info[512];
  u32 checksum[4];
  u32 edata2[5120];
  u32 edata2_len;

} krb5asrep_t;

DECLSPEC int decrypt_and_check (LOCAL_AS u32 *S, u32 *data, GLOBAL_AS const u32 *edata2, const u32 edata2_len, const u32 *K2, const u32 *checksum)
{
  rc4_init_128 (S, data);

  u32 out0[4];

  /*
    8 first bytes are nonce, then ASN1 structs (DER encoding: TLV)

    The first byte is always 0x79 (01 1 11001, where 01 = "class=APPLICATION", 1 = "form=constructed", 11001 is application type 25)
    The next byte is the length:

    if length < 128 bytes:
        length is on 1 byte, and the next byte is 0x30 (class=SEQUENCE)
    else if length <= 256:
        length is on 2 bytes, the first byte is 0x81, and the third byte is 0x30 (class=SEQUENCE)
    else if length > 256:
        length is on 3 bytes, the first byte is 0x82, and the fourth byte is 0x30 (class=SEQUENCE)
  */

  rc4_next_16 (S, 0, 0, edata2 + 0, out0);

  if (((out0[2] & 0x00ff80ff) != 0x00300079) &&
      ((out0[2] & 0xFF00FFFF) != 0x30008179) &&
      ((out0[2] & 0x0000FFFF) != 0x00008279 || (out0[3] & 0x000000FF) != 0x00000030))
      return 0;

  rc4_init_128 (S, data);

  u8 i = 0;
  u8 j = 0;

  // init hmac

  u32 w0[4];
  u32 w1[4];
  u32 w2[4];
  u32 w3[4];

  w0[0] = K2[0];
  w0[1] = K2[1];
  w0[2] = K2[2];
  w0[3] = K2[3];
  w1[0] = 0;
  w1[1] = 0;
  w1[2] = 0;
  w1[3] = 0;
  w2[0] = 0;
  w2[1] = 0;
  w2[2] = 0;
  w2[3] = 0;
  w3[0] = 0;
  w3[1] = 0;
  w3[2] = 0;
  w3[3] = 0;

  md5_hmac_ctx_t ctx;

  md5_hmac_init_64 (&ctx, w0, w1, w2, w3);

  int edata2_left;

  for (edata2_left = edata2_len; edata2_left >= 64; edata2_left -= 64)
  {
    j = rc4_next_16 (S, i, j, edata2, w0); i += 16; edata2 += 4;
    j = rc4_next_16 (S, i, j, edata2, w1); i += 16; edata2 += 4;
    j = rc4_next_16 (S, i, j, edata2, w2); i += 16; edata2 += 4;
    j = rc4_next_16 (S, i, j, edata2, w3); i += 16; edata2 += 4;

    md5_hmac_update_64 (&ctx, w0, w1, w2, w3, 64);
  }

  w0[0] = 0;
  w0[1] = 0;
  w0[2] = 0;
  w0[3] = 0;
  w1[0] = 0;
  w1[1] = 0;
  w1[2] = 0;
  w1[3] = 0;
  w2[0] = 0;
  w2[1] = 0;
  w2[2] = 0;
  w2[3] = 0;
  w3[0] = 0;
  w3[1] = 0;
  w3[2] = 0;
  w3[3] = 0;

  if (edata2_left < 16)
  {
    j = rc4_next_16 (S, i, j, edata2, w0); i += 16; edata2 += 4;

    truncate_block_4x4_le_S (w0, edata2_left & 0xf);
  }
  else if (edata2_left < 32)
  {
    j = rc4_next_16 (S, i, j, edata2, w0); i += 16; edata2 += 4;
    j = rc4_next_16 (S, i, j, edata2, w1); i += 16; edata2 += 4;

    truncate_block_4x4_le_S (w1, edata2_left & 0xf);
  }
  else if (edata2_left < 48)
  {
    j = rc4_next_16 (S, i, j, edata2, w0); i += 16; edata2 += 4;
    j = rc4_next_16 (S, i, j, edata2, w1); i += 16; edata2 += 4;
    j = rc4_next_16 (S, i, j, edata2, w2); i += 16; edata2 += 4;

    truncate_block_4x4_le_S (w2, edata2_left & 0xf);
  }
  else
  {
    j = rc4_next_16 (S, i, j, edata2, w0); i += 16; edata2 += 4;
    j = rc4_next_16 (S, i, j, edata2, w1); i += 16; edata2 += 4;
    j = rc4_next_16 (S, i, j, edata2, w2); i += 16; edata2 += 4;
    j = rc4_next_16 (S, i, j, edata2, w3); i += 16; edata2 += 4;

    truncate_block_4x4_le_S (w3, edata2_left & 0xf);
  }

  md5_hmac_update_64 (&ctx, w0, w1, w2, w3, edata2_left);

  md5_hmac_final (&ctx);

  if (checksum[0] != ctx.opad.h[0]) return 0;
  if (checksum[1] != ctx.opad.h[1]) return 0;
  if (checksum[2] != ctx.opad.h[2]) return 0;
  if (checksum[3] != ctx.opad.h[3]) return 0;

  return 1;
}

DECLSPEC void kerb_prepare (const u32 *K, const u32 *checksum, u32 *digest, u32 *K2)
{
  // K1=MD5_HMAC(K,1); with 1 encoded as little indian on 4 bytes (01000000 in hexa);

  u32 w0[4];
  u32 w1[4];
  u32 w2[4];
  u32 w3[4];

  w0[0] = K[0];
  w0[1] = K[1];
  w0[2] = K[2];
  w0[3] = K[3];
  w1[0] = 0;
  w1[1] = 0;
  w1[2] = 0;
  w1[3] = 0;
  w2[0] = 0;
  w2[1] = 0;
  w2[2] = 0;
  w2[3] = 0;
  w3[0] = 0;
  w3[1] = 0;
  w3[2] = 0;
  w3[3] = 0;

  md5_hmac_ctx_t ctx1;

  md5_hmac_init_64 (&ctx1, w0, w1, w2, w3);

  w0[0] = 8;
  w0[1] = 0;
  w0[2] = 0;
  w0[3] = 0;
  w1[0] = 0;
  w1[1] = 0;
  w1[2] = 0;
  w1[3] = 0;
  w2[0] = 0;
  w2[1] = 0;
  w2[2] = 0;
  w2[3] = 0;
  w3[0] = 0;
  w3[1] = 0;
  w3[2] = 0;
  w3[3] = 0;

  md5_hmac_update_64 (&ctx1, w0, w1, w2, w3, 4);

  md5_hmac_final (&ctx1);

  w0[0] = ctx1.opad.h[0];
  w0[1] = ctx1.opad.h[1];
  w0[2] = ctx1.opad.h[2];
  w0[3] = ctx1.opad.h[3];
  w1[0] = 0;
  w1[1] = 0;
  w1[2] = 0;
  w1[3] = 0;
  w2[0] = 0;
  w2[1] = 0;
  w2[2] = 0;
  w2[3] = 0;
  w3[0] = 0;
  w3[1] = 0;
  w3[2] = 0;
  w3[3] = 0;

  md5_hmac_ctx_t ctx;

  md5_hmac_init_64 (&ctx, w0, w1, w2, w3);

  w0[0] = checksum[0];
  w0[1] = checksum[1];
  w0[2] = checksum[2];
  w0[3] = checksum[3];
  w1[0] = 0;
  w1[1] = 0;
  w1[2] = 0;
  w1[3] = 0;
  w2[0] = 0;
  w2[1] = 0;
  w2[2] = 0;
  w2[3] = 0;
  w3[0] = 0;
  w3[1] = 0;
  w3[2] = 0;
  w3[3] = 0;

  md5_hmac_update_64 (&ctx, w0, w1, w2, w3, 16);

  md5_hmac_final (&ctx);

  digest[0] = ctx.opad.h[0];
  digest[1] = ctx.opad.h[1];
  digest[2] = ctx.opad.h[2];
  digest[3] = ctx.opad.h[3];

  K2[0] = ctx1.opad.h[0];
  K2[1] = ctx1.opad.h[1];
  K2[2] = ctx1.opad.h[2];
  K2[3] = ctx1.opad.h[3];
}

KERNEL_FQ void m18200_mxx (KERN_ATTR_ESALT (krb5asrep_t))
{
  /**
   * modifier
   */

  const u64 lid = get_local_id (0);
  const u64 gid = get_global_id (0);

  if (gid >= gid_max) return;

  /**
   * base
   */

  LOCAL_VK u32 S[64 * FIXED_LOCAL_SIZE];

  u32 checksum[4];

  checksum[0] = esalt_bufs[DIGESTS_OFFSET].checksum[0];
  checksum[1] = esalt_bufs[DIGESTS_OFFSET].checksum[1];
  checksum[2] = esalt_bufs[DIGESTS_OFFSET].checksum[2];
  checksum[3] = esalt_bufs[DIGESTS_OFFSET].checksum[3];

  md4_ctx_t ctx0;

  md4_init (&ctx0);

  md4_update_global_utf16le (&ctx0, pws[gid].i, pws[gid].pw_len);

  /**
   * loop
   */

  for (u32 il_pos = 0; il_pos < il_cnt; il_pos++)
  {
    md4_ctx_t ctx = ctx0;

    md4_update_global_utf16le (&ctx, combs_buf[il_pos].i, combs_buf[il_pos].pw_len);

    md4_final (&ctx);

    u32 digest[4];

    u32 K2[4];

    kerb_prepare (ctx.h, checksum, digest, K2);

    if (decrypt_and_check (S, digest, esalt_bufs[DIGESTS_OFFSET].edata2, esalt_bufs[DIGESTS_OFFSET].edata2_len, K2, checksum) == 1)
    {
      if (hc_atomic_inc (&hashes_shown[DIGESTS_OFFSET]) == 0)
      {
        mark_hash (plains_buf, d_return_buf, SALT_POS, digests_cnt, 0, DIGESTS_OFFSET + 0, gid, il_pos, 0, 0);
      }
    }
  }
}

KERNEL_FQ void m18200_sxx (KERN_ATTR_ESALT (krb5asrep_t))
{
  /**
   * modifier
   */

  const u64 lid = get_local_id (0);
  const u64 gid = get_global_id (0);

  if (gid >= gid_max) return;

  /**
   * base
   */

  LOCAL_VK u32 S[64 * FIXED_LOCAL_SIZE];

  u32 checksum[4];

  checksum[0] = esalt_bufs[DIGESTS_OFFSET].checksum[0];
  checksum[1] = esalt_bufs[DIGESTS_OFFSET].checksum[1];
  checksum[2] = esalt_bufs[DIGESTS_OFFSET].checksum[2];
  checksum[3] = esalt_bufs[DIGESTS_OFFSET].checksum[3];

  md4_ctx_t ctx0;

  md4_init (&ctx0);

  md4_update_global_utf16le (&ctx0, pws[gid].i, pws[gid].pw_len);

  /**
   * loop
   */

  for (u32 il_pos = 0; il_pos < il_cnt; il_pos++)
  {
    md4_ctx_t ctx = ctx0;

    md4_update_global_utf16le (&ctx, combs_buf[il_pos].i, combs_buf[il_pos].pw_len);

    md4_final (&ctx);

    u32 digest[4];

    u32 K2[4];

    kerb_prepare (ctx.h, checksum, digest, K2);

    if (decrypt_and_check (S, digest, esalt_bufs[DIGESTS_OFFSET].edata2, esalt_bufs[DIGESTS_OFFSET].edata2_len, K2, checksum) == 1)
    {
      if (hc_atomic_inc (&hashes_shown[DIGESTS_OFFSET]) == 0)
      {
        mark_hash (plains_buf, d_return_buf, SALT_POS, digests_cnt, 0, DIGESTS_OFFSET + 0, gid, il_pos, 0, 0);
      }
    }
  }
}
