lib/crypto/md5.c

   1 /*
   2  * This code implements the MD5 message-digest algorithm.
   3  * The algorithm is due to Ron Rivest.  This code was
   4  * written by Colin Plumb in 1993, no copyright is claimed.
   5  * This code is in the public domain; do with it what you wish.
   6  *
   7  * Equivalent code is available from RSA Data Security, Inc.
   8  * This code has been tested against that, and is equivalent,
   9  * except that you don't need to include two pages of legalese
  10  * with every copy.
  11  *
  12  * To compute the message digest of a chunk of bytes, declare an
  13  * MD5Context structure, pass it to MD5Init, call MD5Update as
  14  * needed on buffers full of bytes, and then call MD5Final, which
  15  * will fill a supplied 16-byte array with the digest.
  16  */
  17
  18 /* This code slightly modified to fit into Samba by
  19    abartlet@samba.org Jun 2001 */
  20
  21 #include "replace.h"
  22
  23 #include "md5.h"
  24
  25
  26 static void MD5Transform(uint32_t buf[4], uint32_t const in[16]);
  27
  28 /*
  29  * Note: this code is harmless on little-endian machines.
  30  */
  31 static void byteReverse(uint8_t *buf, unsigned int longs)
  32 {
  33     uint32_t t;
  34     do {
  35         t = (uint32_t) ((unsigned int) buf[3] << 8 | buf[2]) << 16 |
  36             ((unsigned int) buf[1] << 8 | buf[0]);
  37         *(uint32_t *) buf = t;
  38         buf += 4;
  39     } while (--longs);
  40 }
  41
  42 /*
  43  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  44  * initialization constants.
  45  */
  46 _PUBLIC_ void MD5Init(MD5_CTX *ctx)
  47 {
  48     ctx->buf[0] = 0x67452301;
  49     ctx->buf[1] = 0xefcdab89;
  50     ctx->buf[2] = 0x98badcfe;
  51     ctx->buf[3] = 0x10325476;
  52
  53     ctx->bits[0] = 0;
  54     ctx->bits[1] = 0;
  55 }
  56
  57 /*
  58  * Update context to reflect the concatenation of another buffer full
  59  * of bytes.
  60  */
  61 _PUBLIC_ void MD5Update(MD5_CTX *ctx, const uint8_t *buf, size_t len)
  62 {
  63     register uint32_t t;
  64
  65     /* Update bitcount */
  66
  67     t = ctx->bits[0];
  68     if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
  69         ctx->bits[1]++;         /* Carry from low to high */
  70     ctx->bits[1] += len >> 29;
  71
  72     t = (t >> 3) & 0x3f;        /* Bytes already in shsInfo->data */
  73
  74     /* Handle any leading odd-sized chunks */
  75
  76     if (t) {
  77         uint8_t *p = (uint8_t *) ctx->in + t;
  78
  79         t = 64 - t;
  80         if (len < t) {
  81             memmove(p, buf, len);
  82             return;
  83         }
  84         memmove(p, buf, t);
  85         byteReverse(ctx->in, 16);
  86         MD5Transform(ctx->buf, (uint32_t *) ctx->in);
  87         buf += t;
  88         len -= t;
  89     }
  90     /* Process data in 64-byte chunks */
  91
  92     while (len >= 64) {
  93         memmove(ctx->in, buf, 64);
  94         byteReverse(ctx->in, 16);
  95         MD5Transform(ctx->buf, (uint32_t *) ctx->in);
  96         buf += 64;
  97         len -= 64;
  98     }
  99
 100     /* Handle any remaining bytes of data. */
 101
 102     memmove(ctx->in, buf, len);
 103 }
 104
 105 /*
 106  * Final wrapup - pad to 64-byte boundary with the bit pattern
 107  * 1 0* (64-bit count of bits processed, MSB-first)
 108  */
 109 _PUBLIC_ void MD5Final(uint8_t digest[16], MD5_CTX *ctx)
 110 {
 111     unsigned int count;
 112     uint8_t *p;
 113
 114     /* Compute number of bytes mod 64 */
 115     count = (ctx->bits[0] >> 3) & 0x3F;
 116
 117     /* Set the first char of padding to 0x80.  This is safe since there is
 118        always at least one byte free */
 119     p = ctx->in + count;
 120     *p++ = 0x80;
 121
 122     /* Bytes of padding needed to make 64 bytes */
 123     count = 64 - 1 - count;
 124
 125     /* Pad out to 56 mod 64 */
 126     if (count < 8) {
 127         /* Two lots of padding:  Pad the first block to 64 bytes */
 128         memset(p, 0, count);
 129         byteReverse(ctx->in, 16);
 130         MD5Transform(ctx->buf, (uint32_t *) ctx->in);
 131
 132         /* Now fill the next block with 56 bytes */
 133         memset(ctx->in, 0, 56);
 134     } else {
 135         /* Pad block to 56 bytes */
 136         memset(p, 0, count - 8);
 137     }
 138     byteReverse(ctx->in, 14);
 139
 140     /* Append length in bits and transform.
 141      * Use memcpy to avoid strict-aliasing problems.
 142      * This way it can be optimized.
 143      */
 144     memcpy(&ctx->in[14 * sizeof(uint32_t)], &ctx->bits[0], sizeof(uint32_t));
 145     memcpy(&ctx->in[15 * sizeof(uint32_t)], &ctx->bits[1], sizeof(uint32_t));
 146
 147     MD5Transform(ctx->buf, (uint32_t *) ctx->in);
 148     byteReverse((uint8_t *) ctx->buf, 4);
 149     memmove(digest, ctx->buf, 16);
 150     memset(ctx, 0, sizeof(*ctx));       /* In case it's sensitive */
 151 }
 152
 153 /* The four core functions - F1 is optimized somewhat */
 154
 155 /* #define F1(x, y, z) (x & y | ~x & z) */
 156 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 157 #define F2(x, y, z) F1(z, x, y)
 158 #define F3(x, y, z) (x ^ y ^ z)
 159 #define F4(x, y, z) (y ^ (x | ~z))
 160
 161 /* This is the central step in the MD5 algorithm. */
 162 #define MD5STEP(f, w, x, y, z, data, s) \
 163         ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
 164
 165 /*
 166  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 167  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 168  * the data and converts bytes into longwords for this routine.
 169  */
 170 static void MD5Transform(uint32_t buf[4], uint32_t const in[16])
 171 {
 172     register uint32_t a, b, c, d;
 173
 174     a = buf[0];
 175     b = buf[1];
 176     c = buf[2];
 177     d = buf[3];
 178
 179     MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 180     MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 181     MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 182     MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 183     MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 184     MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 185     MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 186     MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 187     MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 188     MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 189     MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 190     MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 191     MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 192     MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 193     MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 194     MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 195
 196     MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 197     MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 198     MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 199     MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 200     MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 201     MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 202     MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 203     MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 204     MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 205     MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 206     MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 207     MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 208     MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 209     MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 210     MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 211     MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 212
 213     MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 214     MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 215     MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 216     MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 217     MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 218     MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 219     MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 220     MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 221     MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 222     MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 223     MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 224     MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 225     MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 226     MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 227     MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 228     MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 229
 230     MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 231     MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 232     MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 233     MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 234     MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 235     MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 236     MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 237     MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 238     MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 239     MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 240     MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 241     MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 242     MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 243     MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 244     MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 245     MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 246
 247     buf[0] += a;
 248     buf[1] += b;
 249     buf[2] += c;
 250     buf[3] += d;
 251 }