/*++

Copyright (c) 2004 - 2007, Intel Corporation
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution.  The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

Module Name:

  Md5.c

Abstract:

  Implementation of MD5 algorithm

--*/

#include "Md5.h"

STATIC CONST UINT32  MD5_K[][2] = {
  { 0, 1 },
  { 1, 5 },
  { 5, 3 },
  { 0, 7 }
};

STATIC CONST UINT32  MD5_S[][4] = {
  { 7, 22, 17, 12 },
  { 5, 20, 14, 9 },
  { 4, 23, 16 ,11 },
  { 6, 21, 15, 10 },
};

STATIC CONST UINT32  MD5_T[] = {
  0xD76AA478, 0xE8C7B756, 0x242070DB, 0xC1BDCEEE,
  0xF57C0FAF, 0x4787C62A, 0xA8304613, 0xFD469501,
  0x698098D8, 0x8B44F7AF, 0xFFFF5BB1, 0x895CD7BE,
  0x6B901122, 0xFD987193, 0xA679438E, 0x49B40821,
  0xF61E2562, 0xC040B340, 0x265E5A51, 0xE9B6C7AA,
  0xD62F105D, 0x02441453, 0xD8A1E681, 0xE7D3FBC8,
  0x21E1CDE6, 0xC33707D6, 0xF4D50D87, 0x455A14ED,
  0xA9E3E905, 0xFCEFA3F8, 0x676F02D9, 0x8D2A4C8A,
  0xFFFA3942, 0x8771F681, 0x6D9D6122, 0xFDE5380C,
  0xA4BEEA44, 0x4BDECFA9, 0xF6BB4B60, 0xBEBFBC70,
  0x289B7EC6, 0xEAA127FA, 0xD4EF3085, 0x04881D05,
  0xD9D4D039, 0xE6DB99E5, 0x1FA27CF8, 0xC4AC5665,
  0xF4292244, 0x432AFF97, 0xAB9423A7, 0xFC93A039,
  0x655B59C3, 0x8F0CCC92, 0xFFEFF47D, 0x85845DD1,
  0x6FA87E4F, 0xFE2CE6E0, 0xA3014314, 0x4E0811A1,
  0xF7537E82, 0xBD3AF235, 0x2AD7D2BB, 0xEB86D391
};

STATIC CONST UINT8 Md5HashPadding[] =
{
  0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 
};

//
// ROTATE_LEFT rotates x left n bits.
//
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))

#define SA            S[j & 3]
#define SB            S[(j + 1) & 3]
#define SC            S[(j + 2) & 3]
#define SD            S[(j + 3) & 3]

//
// TF1, TF2, TF3, TF4 are basic MD5 transform functions
//
UINT32 TF1 (UINT32 A, UINT32 B, UINT32 C)
{
  return (A & B) | (~A & C);
}

UINT32 TF2 (UINT32 A, UINT32 B, UINT32 C)
{
  return (A & C) | (B & ~C);
}

UINT32 TF3 (UINT32 A, UINT32 B, UINT32 C)
{
  return A ^ B ^ C;
}

UINT32 TF4 (UINT32 A, UINT32 B, UINT32 C)
{
  return B ^ (A | ~C);
}

typedef
UINT32
(*MD5_TRANSFORM_FUNC) (
  IN UINT32  A,
  IN UINT32  B,
  IN UINT32  C
  );

STATIC CONST MD5_TRANSFORM_FUNC MD5_F[] = {
  TF1,
  TF2,
  TF3,
  TF4
};

STATIC
VOID
MD5Transform (
  IN MD5_CTX  *Md5Ctx
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  Md5Ctx  - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  UINT32  i;
  UINT32  j;
  UINT32  S[MD5_HASHSIZE >> 2];
  UINT32  *X;
  UINT32  k;
  UINT32  t;

  X = (UINT32 *) Md5Ctx->M;

  //
  // Copy MD5 states to S
  //
  NetCopyMem (S, Md5Ctx->States, MD5_HASHSIZE);

  t = 0;
  for (i = 0; i < 4; i++) {
    k = MD5_K[i][0];
    for (j = 16; j > 0; j--) {
      SA += (*MD5_F[i]) (SB, SC, SD) + X[k] + MD5_T[t];
      SA  = ROTATE_LEFT (SA, MD5_S[i][j & 3]);
      SA += SB;

      k += MD5_K[i][1];
      k &= 15;

      t++;
    }
  }

  for (i = 0; i < 4; i++) {
    Md5Ctx->States[i] += S[i];
  }
}

STATIC
VOID
MD5UpdateBlock (
  IN MD5_CTX      *Md5Ctx,
  IN CONST UINT8  *Data,
  IN       UINTN  DataLen
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  Md5Ctx  - GC_TODO: add argument description
  Data    - GC_TODO: add argument description
  DataLen - GC_TODO: add argument description

Returns:

  GC_TODO: add return values

--*/
{
  UINTN Limit;

  for (Limit = 64 - Md5Ctx->Count; DataLen >= 64 - Md5Ctx->Count; Limit = 64) {
    NetCopyMem (Md5Ctx->M + Md5Ctx->Count, (VOID *)Data, Limit);
    MD5Transform (Md5Ctx);
    
    Md5Ctx->Count = 0;
    Data         += Limit;
    DataLen      -= Limit;
  }

  NetCopyMem (Md5Ctx->M + Md5Ctx->Count, (VOID *)Data, DataLen);
  Md5Ctx->Count += DataLen;
}

EFI_STATUS
MD5Init (
  IN MD5_CTX  *Md5Ctx
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  Md5Ctx  - GC_TODO: add argument description

Returns:

  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  NetZeroMem (Md5Ctx, sizeof (*Md5Ctx));

  //
  // Set magic initialization constants.
  //
  Md5Ctx->States[0] = 0x67452301;
  Md5Ctx->States[1] = 0xefcdab89;
  Md5Ctx->States[2] = 0x98badcfe;
  Md5Ctx->States[3] = 0x10325476;  

  return EFI_SUCCESS;
}

EFI_STATUS
MD5Update (
  IN  MD5_CTX  *Md5Ctx,
  IN  VOID     *Data,
  IN  UINTN    DataLen
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  Md5Ctx  - GC_TODO: add argument description
  Data    - GC_TODO: add argument description
  DataLen - GC_TODO: add argument description

Returns:

  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  if (EFI_ERROR (Md5Ctx->Status)) {
    return Md5Ctx->Status;
  }

  MD5UpdateBlock (Md5Ctx, (CONST UINT8 *) Data, DataLen);
  Md5Ctx->Length += DataLen;
  return EFI_SUCCESS;
}

EFI_STATUS
MD5Final (
  IN  MD5_CTX  *Md5Ctx,
  OUT UINT8    *HashVal
  )
/*++

Routine Description:

  GC_TODO: Add function description

Arguments:

  Md5Ctx  - GC_TODO: add argument description
  HashVal - GC_TODO: add argument description

Returns:

  EFI_SUCCESS - GC_TODO: Add description for return value

--*/
{
  UINTN PadLength;

  if (Md5Ctx->Status == EFI_ALREADY_STARTED) {
    //
    // Store Hashed value & Zeroize sensitive context information.
    //
    NetCopyMem (HashVal, (UINT8 *) Md5Ctx->States, MD5_HASHSIZE);
    NetZeroMem ((UINT8 *)Md5Ctx, sizeof (*Md5Ctx));
    
    return EFI_SUCCESS;
  }

  if (EFI_ERROR (Md5Ctx->Status)) {
    return Md5Ctx->Status;
  }

  PadLength  = Md5Ctx->Count >= 56 ? 120 : 56;
  PadLength -= Md5Ctx->Count;
  MD5UpdateBlock (Md5Ctx, Md5HashPadding, PadLength);
  Md5Ctx->Length = LShiftU64 (Md5Ctx->Length, 3);
  MD5UpdateBlock (Md5Ctx, (CONST UINT8 *) &Md5Ctx->Length, 8);

  NetZeroMem (Md5Ctx->M, sizeof (Md5Ctx->M));
  Md5Ctx->Length  = 0;
  Md5Ctx->Status  = EFI_ALREADY_STARTED;
  return MD5Final (Md5Ctx, HashVal);
}