md5.cpp

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//
// md5.cpp
//

//

#include"stdafx.h"

#include<stdlib.h>
#include"stdmacros.h"
#include"md5.h"
#include"contract.h"

voidMD5::Init(BOOL fConstructed)
 {
 STATIC_CONTRACT_NOTHROW;
 STATIC_CONTRACT_GC_NOTRIGGER;

// These two fields are read only, and so initialization thereof can be
// omitted on the second and subsequent hashes using this same instance.
//
if (!fConstructed)
 {
memset(m_padding, 0, 64);
 m_padding[0]=0x80;
 }

 m_cbitHashed = 0;
 m_cbData = 0;
 u.m_a = 0x67452301; // magic
 u.m_b = 0xefcdab89; // ... constants
 u.m_c = 0x98badcfe; // ... per
 u.m_d = 0x10325476; // .. RFC1321
 }


voidMD5::HashMore(constvoid* pvInput, ULONG cbInput)
// Hash the additional data into the state
 {
 STATIC_CONTRACT_NOTHROW;
 STATIC_CONTRACT_GC_NOTRIGGER;

const BYTE* pbInput = (const BYTE*)pvInput;

 m_cbitHashed += (((ULONGLONG)cbInput) <<3);

 ULONG cbRemaining = 64 - m_cbData;
if (cbInput < cbRemaining)
 {
// It doesn't fill up the buffer, so just store it
memcpy(&m_data[m_cbData], pbInput, cbInput);
 m_cbData += cbInput;
 }
else
 {
// It does fill up the buffer. Fill up all that it will take
memcpy(&m_data[m_cbData], pbInput, cbRemaining);

// Hash the now-full buffer
MD5Transform(m_state, (ULONG*)&m_data[0]);
#ifdef _PREFAST_
#pragma warning(push)
#pragma warning(disable:22019) // Suppress this OACR warning 22019:
// 'cbInput-=cbRemaining' may be greater than 'cbInput'. This can be caused by integer underflow.
// This could yield an incorrect loop index 'cbInput>=64'
// We only enter the else clause here if cbInput >= cbRemaining
#endif
 cbInput -= cbRemaining;
#ifdef _PREFAST_
#pragma warning(pop)
#endif
 pbInput += cbRemaining;

// Hash the data in 64-byte runs, starting just after what we've copied
while (cbInput >= 64)
 {
if (IS_ALIGNED(pbInput, sizeof(ULONG)))
 {
MD5Transform(m_state, (ULONG*)pbInput);
 }
else
 {
 ULONG inputCopy[64 / sizeof(ULONG)];
memcpy(inputCopy, pbInput, sizeof(inputCopy));
MD5Transform(m_state, inputCopy);
 }
 pbInput += 64;
 cbInput -= 64;
 }

// Store the tail of the input into the buffer
memcpy(&m_data[0], pbInput, cbInput);
 m_cbData = cbInput;
 }
 }


voidMD5::GetHashValue(MD5HASHDATA* phash)
// Finalize the hash by appending the necessary padding and length count. Then
// return the final hash value.
 {
 STATIC_CONTRACT_NOTHROW;
 STATIC_CONTRACT_GC_NOTRIGGER;

union {
 ULONGLONG cbitHashed;
 BYTE rgb[8];
 }u;

// Remember how many bits there were in the input data
 u.cbitHashed = m_cbitHashed;

// Calculate amount of padding needed. Enough so total byte count hashed is 56 mod 64
 ULONG cbPad = (m_cbData < 56 ? 56-m_cbData : 120-m_cbData);

// Hash the padding
HashMore(&m_padding[0], cbPad);

// Hash the (before padding) bit length
HashMore(&u.rgb[0], 8);

// Return the hash value
memcpy(phash, &this->u.m_a, 16);
 }




////////////////////////////////////////////////////////////////
//
// ROTATE_LEFT should be a macro that updates its first operand
// with its present value rotated left by the amount of its
// second operand, which is always a constant.
//
// One way to portably do it would be
//
// #define ROL(x, n) (((x) << (n)) | ((x) >> (32-(n))))
// #define ROTATE_LEFT(x,n) (x) = ROL(x,n)
//
// but our compiler has an intrinsic!

 #if (defined(_X86_) || defined(_ARM_)) && defined(PLATFORM_UNIX)
 #defineROL(x, n) (((x) << (n)) | ((x) >> (32-(n))))
 #defineROTATE_LEFT(x,n) (x) = ROL(x,n)
 #else
 #defineROTATE_LEFT(x,n) (x) = _lrotl(x,n)
 #endif

////////////////////////////////////////////////////////////////
//
// Constants used in each of the various rounds

 #defineMD5_S117
 #defineMD5_S1212
 #defineMD5_S1317
 #defineMD5_S1422
 #defineMD5_S215
 #defineMD5_S229
 #defineMD5_S2314
 #defineMD5_S2420
 #defineMD5_S314
 #defineMD5_S3211
 #defineMD5_S3316
 #defineMD5_S3423
 #defineMD5_S416
 #defineMD5_S4210
 #defineMD5_S4315
 #defineMD5_S4421

////////////////////////////////////////////////////////////////
//
// The core twiddle functions

// #define F(x, y, z) (((x) & (y)) | ((~x) & (z))) // the function per the standard
 #defineF(x, y, z) ((((z) ^ (y)) & (x)) ^ (z)) // an alternate encoding

// #define G(x, y, z) (((x) & (z)) | ((y) & (~z))) // the function per the standard
 #defineG(x, y, z) ((((x) ^ (y)) & (z)) ^ (y)) // an alternate encoding

 #defineH(x, y, z) ((x) ^ (y) ^ (z))

 #defineI(x, y, z) ((y) ^ ((x) | (~(z))))

 #defineAC(ac) ((ULONG)(ac))

////////////////////////////////////////////////////////////////

 #defineFF(a, b, c, d, x, s, ac) { \
 (a) += F (b,c,d) + (x) + (AC(ac)); \
ROTATE_LEFT (a, s); \
 (a) += (b); \
 }

////////////////////////////////////////////////////////////////

 #defineGG(a, b, c, d, x, s, ac) { \
 (a) += G (b,c,d) + (x) + (AC(ac)); \
ROTATE_LEFT (a, s); \
 (a) += (b); \
 }

////////////////////////////////////////////////////////////////

 #defineHH(a, b, c, d, x, s, ac) { \
 (a) += H (b,c,d) + (x) + (AC(ac)); \
ROTATE_LEFT (a, s); \
 (a) += (b); \
 }

////////////////////////////////////////////////////////////////

 #defineII(a, b, c, d, x, s, ac) { \
 (a) += I (b,c,d) + (x) + (AC(ac)); \
ROTATE_LEFT (a, s); \
 (a) += (b); \
 }

void __stdcall MD5Transform(ULONG state[4], const ULONG* data)
 {
 STATIC_CONTRACT_NOTHROW;
 STATIC_CONTRACT_GC_NOTRIGGER;

_ASSERTE(IS_ALIGNED(data, sizeof(ULONG)));

 ULONG a=state[0];
 ULONG b=state[1];
 ULONG c=state[2];
 ULONG d=state[3];

// Round 1
FF (a, b, c, d, data[ 0], MD5_S11, 0xd76aa478); // 1
FF (d, a, b, c, data[ 1], MD5_S12, 0xe8c7b756); // 2
FF (c, d, a, b, data[ 2], MD5_S13, 0x242070db); // 3
FF (b, c, d, a, data[ 3], MD5_S14, 0xc1bdceee); // 4
FF (a, b, c, d, data[ 4], MD5_S11, 0xf57c0faf); // 5
FF (d, a, b, c, data[ 5], MD5_S12, 0x4787c62a); // 6
FF (c, d, a, b, data[ 6], MD5_S13, 0xa8304613); // 7
FF (b, c, d, a, data[ 7], MD5_S14, 0xfd469501); // 8
FF (a, b, c, d, data[ 8], MD5_S11, 0x698098d8); // 9
FF (d, a, b, c, data[ 9], MD5_S12, 0x8b44f7af); // 10
FF (c, d, a, b, data[10], MD5_S13, 0xffff5bb1); // 11
FF (b, c, d, a, data[11], MD5_S14, 0x895cd7be); // 12
FF (a, b, c, d, data[12], MD5_S11, 0x6b901122); // 13
FF (d, a, b, c, data[13], MD5_S12, 0xfd987193); // 14
FF (c, d, a, b, data[14], MD5_S13, 0xa679438e); // 15
FF (b, c, d, a, data[15], MD5_S14, 0x49b40821); // 16

// Round 2
GG (a, b, c, d, data[ 1], MD5_S21, 0xf61e2562); // 17
GG (d, a, b, c, data[ 6], MD5_S22, 0xc040b340); // 18
GG (c, d, a, b, data[11], MD5_S23, 0x265e5a51); // 19
GG (b, c, d, a, data[ 0], MD5_S24, 0xe9b6c7aa); // 20
GG (a, b, c, d, data[ 5], MD5_S21, 0xd62f105d); // 21
GG (d, a, b, c, data[10], MD5_S22, 0x2441453); // 22
GG (c, d, a, b, data[15], MD5_S23, 0xd8a1e681); // 23
GG (b, c, d, a, data[ 4], MD5_S24, 0xe7d3fbc8); // 24
GG (a, b, c, d, data[ 9], MD5_S21, 0x21e1cde6); // 25
GG (d, a, b, c, data[14], MD5_S22, 0xc33707d6); // 26
GG (c, d, a, b, data[ 3], MD5_S23, 0xf4d50d87); // 27
GG (b, c, d, a, data[ 8], MD5_S24, 0x455a14ed); // 28
GG (a, b, c, d, data[13], MD5_S21, 0xa9e3e905); // 29
GG (d, a, b, c, data[ 2], MD5_S22, 0xfcefa3f8); // 30
GG (c, d, a, b, data[ 7], MD5_S23, 0x676f02d9); // 31
GG (b, c, d, a, data[12], MD5_S24, 0x8d2a4c8a); // 32

// Round 3
HH (a, b, c, d, data[ 5], MD5_S31, 0xfffa3942); // 33
HH (d, a, b, c, data[ 8], MD5_S32, 0x8771f681); // 34
HH (c, d, a, b, data[11], MD5_S33, 0x6d9d6122); // 35
HH (b, c, d, a, data[14], MD5_S34, 0xfde5380c); // 36
HH (a, b, c, d, data[ 1], MD5_S31, 0xa4beea44); // 37
HH (d, a, b, c, data[ 4], MD5_S32, 0x4bdecfa9); // 38
HH (c, d, a, b, data[ 7], MD5_S33, 0xf6bb4b60); // 39
HH (b, c, d, a, data[10], MD5_S34, 0xbebfbc70); // 40
HH (a, b, c, d, data[13], MD5_S31, 0x289b7ec6); // 41
HH (d, a, b, c, data[ 0], MD5_S32, 0xeaa127fa); // 42
HH (c, d, a, b, data[ 3], MD5_S33, 0xd4ef3085); // 43
HH (b, c, d, a, data[ 6], MD5_S34, 0x4881d05); // 44
HH (a, b, c, d, data[ 9], MD5_S31, 0xd9d4d039); // 45
HH (d, a, b, c, data[12], MD5_S32, 0xe6db99e5); // 46
HH (c, d, a, b, data[15], MD5_S33, 0x1fa27cf8); // 47
HH (b, c, d, a, data[ 2], MD5_S34, 0xc4ac5665); // 48

// Round 4
II (a, b, c, d, data[ 0], MD5_S41, 0xf4292244); // 49
II (d, a, b, c, data[ 7], MD5_S42, 0x432aff97); // 50
II (c, d, a, b, data[14], MD5_S43, 0xab9423a7); // 51
II (b, c, d, a, data[ 5], MD5_S44, 0xfc93a039); // 52
II (a, b, c, d, data[12], MD5_S41, 0x655b59c3); // 53
II (d, a, b, c, data[ 3], MD5_S42, 0x8f0ccc92); // 54
II (c, d, a, b, data[10], MD5_S43, 0xffeff47d); // 55
II (b, c, d, a, data[ 1], MD5_S44, 0x85845dd1); // 56
II (a, b, c, d, data[ 8], MD5_S41, 0x6fa87e4f); // 57
II (d, a, b, c, data[15], MD5_S42, 0xfe2ce6e0); // 58
II (c, d, a, b, data[ 6], MD5_S43, 0xa3014314); // 59
II (b, c, d, a, data[13], MD5_S44, 0x4e0811a1); // 60
II (a, b, c, d, data[ 4], MD5_S41, 0xf7537e82); // 61
II (d, a, b, c, data[11], MD5_S42, 0xbd3af235); // 62
II (c, d, a, b, data[ 2], MD5_S43, 0x2ad7d2bb); // 63
II (b, c, d, a, data[ 9], MD5_S44, 0xeb86d391); // 64

 state[0] += a;
 state[1] += b;
 state[2] += c;
 state[3] += d;
 }