md5_utils.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  * Changed so as no longer to depend on Colin Plumb's `usual.h' header
  18  * definitions
  19  *  - Ian Jackson <ian@chiark.greenend.org.uk>.
  20  * Still in the public domain.
  21  */
  22
  23 #include <string.h> /* for memcpy() */
  24
  25 #include "md5_utils.h"
  26
  27 static void byteSwap(UWORD32 *buf, unsigned words) {
  28   md5byte *p;
  29
  30   /* Only swap bytes for big endian machines */
  31   int i = 1;
  32
  33   if (*(char *)&i == 1) return;
  34
  35   p = (md5byte *)buf;
  36
  37   do {
  38     *buf++ = (UWORD32)((unsigned)p[3] << 8 | p[2]) << 16 |
  39              ((unsigned)p[1] << 8 | p[0]);
  40     p += 4;
  41   } while (--words);
  42 }
  43
  44 /*
  45  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  46  * initialization constants.
  47  */
  48 void MD5Init(struct MD5Context *ctx) {
  49   ctx->buf[0] = 0x67452301;
  50   ctx->buf[1] = 0xefcdab89;
  51   ctx->buf[2] = 0x98badcfe;
  52   ctx->buf[3] = 0x10325476;
  53
  54   ctx->bytes[0] = 0;
  55   ctx->bytes[1] = 0;
  56 }
  57
  58 /*
  59  * Update context to reflect the concatenation of another buffer full
  60  * of bytes.
  61  */
  62 void MD5Update(struct MD5Context *ctx, md5byte const *buf, unsigned len) {
  63   UWORD32 t;
  64
  65   /* Update byte count */
  66
  67   t = ctx->bytes[0];
  68
  69   if ((ctx->bytes[0] = t + len) < t)
  70     ctx->bytes[1]++; /* Carry from low to high */
  71
  72   t = 64 - (t & 0x3f); /* Space available in ctx->in (at least 1) */
  73
  74   if (t > len) {
  75     memcpy((md5byte *)ctx->in + 64 - t, buf, len);
  76     return;
  77   }
  78
  79   /* First chunk is an odd size */
  80   memcpy((md5byte *)ctx->in + 64 - t, buf, t);
  81   byteSwap(ctx->in, 16);
  82   MD5Transform(ctx->buf, ctx->in);
  83   buf += t;
  84   len -= t;
  85
  86   /* Process data in 64-byte chunks */
  87   while (len >= 64) {
  88     memcpy(ctx->in, buf, 64);
  89     byteSwap(ctx->in, 16);
  90     MD5Transform(ctx->buf, ctx->in);
  91     buf += 64;
  92     len -= 64;
  93   }
  94
  95   /* Handle any remaining bytes of data. */
  96   memcpy(ctx->in, buf, len);
  97 }
  98
  99 /*
 100  * Final wrapup - pad to 64-byte boundary with the bit pattern
 101  * 1 0* (64-bit count of bits processed, MSB-first)
 102  */
 103 void MD5Final(md5byte digest[16], struct MD5Context *ctx) {
 104   int count = ctx->bytes[0] & 0x3f; /* Number of bytes in ctx->in */
 105   md5byte *p = (md5byte *)ctx->in + count;
 106
 107   /* Set the first char of padding to 0x80.  There is always room. */
 108   *p++ = 0x80;
 109
 110   /* Bytes of padding needed to make 56 bytes (-8..55) */
 111   count = 56 - 1 - count;
 112
 113   if (count < 0) { /* Padding forces an extra block */
 114     memset(p, 0, count + 8);
 115     byteSwap(ctx->in, 16);
 116     MD5Transform(ctx->buf, ctx->in);
 117     p = (md5byte *)ctx->in;
 118     count = 56;
 119   }
 120
 121   memset(p, 0, count);
 122   byteSwap(ctx->in, 14);
 123
 124   /* Append length in bits and transform */
 125   ctx->in[14] = ctx->bytes[0] << 3;
 126   ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
 127   MD5Transform(ctx->buf, ctx->in);
 128
 129   byteSwap(ctx->buf, 4);
 130   memcpy(digest, ctx->buf, 16);
 131   memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
 132 }
 133
 134 #ifndef ASM_MD5
 135
 136 /* The four core functions - F1 is optimized somewhat */
 137
 138 /* #define F1(x, y, z) (x & y | ~x & z) */
 139 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 140 #define F2(x, y, z) F1(z, x, y)
 141 #define F3(x, y, z) (x ^ y ^ z)
 142 #define F4(x, y, z) (y ^ (x | ~z))
 143
 144 /* This is the central step in the MD5 algorithm. */
 145 #define MD5STEP(f, w, x, y, z, in, s) \
 146   (w += f(x, y, z) + in, w = (w << s | w >> (32 - s)) + x)
 147
 148 #if defined(__clang__) && defined(__has_attribute)
 149 #if __has_attribute(no_sanitize)
 150 #define AOM_NO_UNSIGNED_OVERFLOW_CHECK \
 151   __attribute__((no_sanitize("unsigned-integer-overflow")))
 152 #endif
 153 #endif
 154
 155 #ifndef AOM_NO_UNSIGNED_OVERFLOW_CHECK
 156 #define AOM_NO_UNSIGNED_OVERFLOW_CHECK
 157 #endif
 158
 159 /*
 160  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 161  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 162  * the data and converts bytes into longwords for this routine.
 163  */
 164 AOM_NO_UNSIGNED_OVERFLOW_CHECK void MD5Transform(UWORD32 buf[4],
 165                                                  UWORD32 const in[16]) {
 166   register UWORD32 a, b, c, d;
 167
 168   a = buf[0];
 169   b = buf[1];
 170   c = buf[2];
 171   d = buf[3];
 172
 173   MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 174   MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 175   MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 176   MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 177   MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 178   MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 179   MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 180   MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 181   MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 182   MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 183   MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 184   MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 185   MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 186   MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 187   MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 188   MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 189
 190   MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 191   MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 192   MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 193   MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 194   MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 195   MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 196   MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 197   MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 198   MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 199   MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 200   MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 201   MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 202   MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 203   MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 204   MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 205   MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 206
 207   MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 208   MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 209   MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 210   MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 211   MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 212   MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 213   MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 214   MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 215   MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 216   MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 217   MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 218   MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 219   MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 220   MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 221   MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 222   MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 223
 224   MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 225   MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 226   MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 227   MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 228   MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 229   MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 230   MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 231   MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 232   MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 233   MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 234   MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 235   MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 236   MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 237   MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 238   MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 239   MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 240
 241   buf[0] += a;
 242   buf[1] += b;
 243   buf[2] += c;
 244   buf[3] += d;
 245 }
 246
 247 #undef AOM_NO_UNSIGNED_OVERFLOW_CHECK
 248
 249 #endif