hash_md5.c

Go to the documentation of this file.

/**
 * \file    heivs/hash_md5.c
 * \see     heivs/hash.h
 *
 * Reference code from RFC1321
 */

#include "heivs/hash_md5.h"
#include <stdint.h>
#include <string.h>

struct MD5_CTX
{
    uint32_t state[4];
    uint32_t count[2];
    uint8_t buffer[64];
};

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static void MD5Transform(uint32_t [4], uint8_t [64]);
static void Encode(uint8_t *, uint32_t *, uint32_t);
static void Decode(uint32_t *, uint8_t *, uint32_t);

static const uint8_t PADDING[64] = {
  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/* F, G, H and I are basic MD5 functions.
 */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

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

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
 */
#define FF(a, b, c, d, x, s, ac) { \
 (a) += F ((b), (c), (d)) + (x) + (uint32_t)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
   }
 #define GG(a, b, c, d, x, s, ac) { \
  (a) += G ((b), (c), (d)) + (x) + (uint32_t)(ac); \
  (a) = ROTATE_LEFT ((a), (s)); \
  (a) += (b); \
   }
 #define HH(a, b, c, d, x, s, ac) { \
  (a) += H ((b), (c), (d)) + (x) + (uint32_t)(ac); \
  (a) = ROTATE_LEFT ((a), (s)); \
  (a) += (b); \
   }
 #define II(a, b, c, d, x, s, ac) { \
  (a) += I ((b), (c), (d)) + (x) + (uint32_t)(ac); \
  (a) = ROTATE_LEFT ((a), (s)); \
  (a) += (b); \
   }

static status_e init(struct heivs_hash_t *hash, void *_state, size_t state_size)
{
    struct MD5_CTX *context = (struct MD5_CTX *)_state;

    (void)hash;
    (void)state_size;
    context->count[0] = context->count[1] = 0;

    /* Load magic initialization constants.*/
    context->state[0] = 0x67452301;
    context->state[1] = 0xefcdab89;
    context->state[2] = 0x98badcfe;
    context->state[3] = 0x10325476;

    return NO_ERROR;
}

/* MD5 block update operation. Continues an MD5 message-digest
  operation, processing another message block, and updating the
  context.
 */
void MD5Update (context, input, inputLen)
struct MD5_CTX *context;                                        /* context */
uint8_t *input;                                /* input block */
uint32_t inputLen;                     /* length of input block */
{
  uint32_t i, index, partLen;

  /* Compute number of bytes mod 64 */
  index = (uint32_t)((context->count[0] >> 3) & 0x3F);

  /* Update number of bits */
  if ((context->count[0] += ((uint32_t)inputLen << 3))
   < ((uint32_t)inputLen << 3))
 context->count[1]++;
  context->count[1] += ((uint32_t)inputLen >> 29);

  partLen = 64 - index;

  /* Transform as many times as possible.
*/
  if (inputLen >= partLen) {
 memcpy
   ((void *)&context->buffer[index], (void *)input, partLen);
 MD5Transform (context->state, context->buffer);

 for (i = partLen; i + 63 < inputLen; i += 64)
   MD5Transform (context->state, &input[i]);

 index = 0;
  }
  else
 i = 0;

  /* Buffer remaining input */
  memcpy
 ((void *)&context->buffer[index], (void *)&input[i],
  inputLen-i);
}


static status_e run(struct heivs_hash_t *hash, void *_state, const void *_data, size_t size)
{
    struct MD5_CTX *context = (struct MD5_CTX *)_state;

    (void)hash;
    MD5Update(context, (uint8_t*)_data, size);

    return NO_ERROR;
}

static status_e finish(struct heivs_hash_t *hash, void *_state)
{
    struct MD5_CTX *context = (struct MD5_CTX *)_state;

    uint8_t bits[8];
    uint32_t index, padLen;
    uint8_t digest[128/8];

    (void)hash;
    /* Save number of bits */
    Encode (bits, context->count, 8);

    /* Pad out to 56 mod 64.
    */
    index = (uint32_t)((context->count[0] >> 3) & 0x3f);
    padLen = (index < 56) ? (56 - index) : (120 - index);
    MD5Update(context, PADDING, padLen);

    /* Append length (before padding) */
    MD5Update(context, bits, 8);

    /* Store state in digest */
    Encode(digest, context->state, 16);

    /* Zeroize sensitive information.
    */
    memset((void *)context, 0, sizeof (*context));

    memcpy(context, digest, sizeof(digest));

    return NO_ERROR;
}

static void MD5Transform (uint32_t state[4], uint8_t block[64])
{
  uint32_t a = state[0], b = state[1], c = state[2], d = state[3], x[16];

  Decode (x, block, 64);

  /* Round 1 */
  FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
  FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
  FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
  FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
  FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
  FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
  FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
  FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
  FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
  FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
  FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
  FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
  FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
  FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
  FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
  FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

 /* Round 2 */
  GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
  GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
  GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
  GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
  GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
  GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
  GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
  GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
  GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
  GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
  GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
  GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
  GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
  GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
  GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
  GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

  /* Round 3 */
  HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
  HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
  HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
  HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
  HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
  HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
  HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
  HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
  HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
  HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
  HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
  HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
  HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
  HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
  HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
  HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

  /* Round 4 */
  II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
  II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
  II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
  II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
  II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
  II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
  II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
  II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
  II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
  II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
  II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
  II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
  II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
  II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
  II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
  II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

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

  /* Zeroize sensitive information. */
  memset(x, 0, sizeof (x));
}

static void Encode (output, input, len)
uint8_t *output;
uint32_t *input;
uint32_t len;
{
  uint32_t i, j;

  for (i = 0, j = 0; j < len; i++, j += 4) {
 output[j] = (uint8_t)(input[i] & 0xff);
 output[j+1] = (uint8_t)((input[i] >> 8) & 0xff);
 output[j+2] = (uint8_t)((input[i] >> 16) & 0xff);
 output[j+3] = (uint8_t)((input[i] >> 24) & 0xff);
  }
}

/* Decodes input (uint8_t) into output (uint32_t). Assumes len is
  a multiple of 4.
 */
static void Decode (output, input, len)
uint32_t *output;
uint8_t *input;
uint32_t len;
{
  uint32_t i, j;

  for (i = 0, j = 0; j < len; i++, j += 4)
 output[i] = ((uint32_t)input[j]) | (((uint32_t)input[j+1]) << 8) |
   (((uint32_t)input[j+2]) << 16) | (((uint32_t)input[j+3]) << 24);
}

struct heivs_hash_t hash_md5 =
{
        .name           = "hash_md5",
        .init           = init,
        .run            = run,
        .finish         = finish,

        .state_size     = sizeof(struct MD5_CTX),
        .hash_size      = 128/8,
};