apt-pkg/contrib/md5.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: md5.cc,v 1.12 2001/05/13 05:15:03 jgg Exp $
   4 /* ######################################################################
   5
   6    MD5Sum - MD5 Message Digest Algorithm.
   7
   8    This code implements the MD5 message-digest algorithm. The algorithm is
   9    due to Ron Rivest.  This code was written by Colin Plumb in 1993, no
  10    copyright is claimed. This code is in the public domain; do with it what
  11    you wish.
  12
  13    Equivalent code is available from RSA Data Security, Inc. This code has
  14    been tested against that, and is equivalent, except that you don't need to
  15    include two pages of legalese with every copy.
  16
  17    To compute the message digest of a chunk of bytes, instantiate the class,
  18    and repeatedly call one of the Add() members. When finished the Result
  19    method will return the Hash and finalize the value.
  20
  21    Changed so as no longer to depend on Colin Plumb's `usual.h' header
  22    definitions; now uses stuff from dpkg's config.h.
  23     - Ian Jackson <ijackson@nyx.cs.du.edu>.
  24
  25    Changed into a C++ interface and made work with APT's config.h.
  26     - Jason Gunthorpe <jgg@gpu.srv.ualberta.ca>
  27
  28    Still in the public domain.
  29
  30    The classes use arrays of char that are a specific size. We cast those
  31    arrays to uint8_t's and go from there. This allows us to advoid using
  32    the uncommon inttypes.h in a public header or internally newing memory.
  33    In theory if C9x becomes nicely accepted
  34
  35    ##################################################################### */
  36                                                                         /*}}}*/
  37 // Include Files                                                        /*{{{*/
  38 #include <apt-pkg/md5.h>
  39 #include <apt-pkg/strutl.h>
  40 #include <apt-pkg/macros.h>
  41
  42 #include <string.h>
  43 #include <unistd.h>
  44 #include <netinet/in.h>                          // For htonl
  45 #include <inttypes.h>
  46 #include <config.h>
  47                                                                         /*}}}*/
  48
  49 // byteSwap - Swap bytes in a buffer                                    /*{{{*/
  50 // ---------------------------------------------------------------------
  51 /* Swap n 32 bit longs in given buffer */
  52 #ifdef WORDS_BIGENDIAN
  53 static void byteSwap(uint32_t *buf, unsigned words)
  54 {
  55    uint8_t *p = (uint8_t *)buf;
  56
  57    do
  58    {
  59       *buf++ = (uint32_t)((unsigned)p[3] << 8 | p[2]) << 16 |
  60          ((unsigned)p[1] << 8 | p[0]);
  61       p += 4;
  62    } while (--words);
  63 }
  64 #else
  65 #define byteSwap(buf,words)
  66 #endif
  67                                                                         /*}}}*/
  68 // MD5Transform - Alters an existing MD5 hash                           /*{{{*/
  69 // ---------------------------------------------------------------------
  70 /* The core of the MD5 algorithm, this alters an existing MD5 hash to
  71    reflect the addition of 16 longwords of new data. Add blocks
  72    the data and converts bytes into longwords for this routine. */
  73
  74 // The four core functions - F1 is optimized somewhat
  75 // #define F1(x, y, z) (x & y | ~x & z)
  76 #define F1(x, y, z) (z ^ (x & (y ^ z)))
  77 #define F2(x, y, z) F1(z, x, y)
  78 #define F3(x, y, z) (x ^ y ^ z)
  79 #define F4(x, y, z) (y ^ (x | ~z))
  80
  81 // This is the central step in the MD5 algorithm.
  82 #define MD5STEP(f,w,x,y,z,in,s) \
  83          (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)
  84
  85 static void MD5Transform(uint32_t buf[4], uint32_t const in[16])
  86 {
  87    register uint32_t a, b, c, d;
  88
  89    a = buf[0];
  90    b = buf[1];
  91    c = buf[2];
  92    d = buf[3];
  93
  94    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
  95    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
  96    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
  97    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
  98    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
  99    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 100    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 101    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 102    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 103    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 104    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 105    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 106    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 107    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 108    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 109    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 110
 111    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 112    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 113    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 114    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 115    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 116    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 117    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 118    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 119    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 120    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 121    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 122    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 123    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 124    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 125    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 126    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 127
 128    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 129    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 130    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 131    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 132    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 133    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 134    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 135    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 136    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 137    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 138    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 139    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 140    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 141    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 142    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 143    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 144
 145    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 146    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 147    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 148    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 149    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 150    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 151    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 152    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 153    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 154    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 155    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 156    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 157    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 158    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 159    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 160    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 161
 162    buf[0] += a;
 163    buf[1] += b;
 164    buf[2] += c;
 165    buf[3] += d;
 166 }
 167                                                                         /*}}}*/
 168 // MD5Summation::MD5Summation - Initialize the summer                   /*{{{*/
 169 // ---------------------------------------------------------------------
 170 /* This assigns the deep magic initial values */
 171 MD5Summation::MD5Summation()
 172 {
 173    uint32_t *buf = (uint32_t *)Buf;
 174    uint32_t *bytes = (uint32_t *)Bytes;
 175
 176    buf[0] = 0x67452301;
 177    buf[1] = 0xefcdab89;
 178    buf[2] = 0x98badcfe;
 179    buf[3] = 0x10325476;
 180
 181    bytes[0] = 0;
 182    bytes[1] = 0;
 183    Done = false;
 184 }
 185                                                                         /*}}}*/
 186 // MD5Summation::Add - 'Add' a data set to the hash                     /*{{{*/
 187 // ---------------------------------------------------------------------
 188 /* */
 189 bool MD5Summation::Add(const unsigned char *data,unsigned long len)
 190 {
 191    if (Done == true)
 192       return false;
 193
 194    uint32_t *buf = (uint32_t *)Buf;
 195    uint32_t *bytes = (uint32_t *)Bytes;
 196    uint32_t *in = (uint32_t *)In;
 197
 198    // Update byte count and carry (this could be done with a long long?)
 199    uint32_t t = bytes[0];
 200    if ((bytes[0] = t + len) < t)
 201       bytes[1]++;
 202
 203    // Space available (at least 1)
 204    t = 64 - (t & 0x3f);
 205    if (t > len)
 206    {
 207       memcpy((unsigned char *)in + 64 - t,data,len);
 208       return true;
 209    }
 210
 211    // First chunk is an odd size
 212    memcpy((unsigned char *)in + 64 - t,data,t);
 213    byteSwap(in, 16);
 214    MD5Transform(buf,in);
 215    data += t;
 216    len -= t;
 217
 218    // Process data in 64-byte chunks
 219    while (len >= 64)
 220    {
 221       memcpy(in,data,64);
 222       byteSwap(in,16);
 223       MD5Transform(buf,in);
 224       data += 64;
 225       len -= 64;
 226    }
 227
 228    // Handle any remaining bytes of data.
 229    memcpy(in,data,len);
 230
 231    return true;
 232 }
 233                                                                         /*}}}*/
 234 // MD5Summation::Result - Returns the value of the sum                  /*{{{*/
 235 // ---------------------------------------------------------------------
 236 /* Because this must add in the last bytes of the series it prevents anyone
 237    from calling add after. */
 238 MD5SumValue MD5Summation::Result()
 239 {
 240    uint32_t *buf = (uint32_t *)Buf;
 241    uint32_t *bytes = (uint32_t *)Bytes;
 242    uint32_t *in = (uint32_t *)In;
 243
 244    if (Done == false)
 245    {
 246       // Number of bytes in In
 247       int count = bytes[0] & 0x3f;
 248       unsigned char *p = (unsigned char *)in + count;
 249
 250       // Set the first char of padding to 0x80.  There is always room.
 251       *p++ = 0x80;
 252
 253       // Bytes of padding needed to make 56 bytes (-8..55)
 254       count = 56 - 1 - count;
 255
 256       // Padding forces an extra block
 257       if (count < 0)
 258       {
 259          memset(p,0,count + 8);
 260          byteSwap(in, 16);
 261          MD5Transform(buf,in);
 262          p = (unsigned char *)in;
 263          count = 56;
 264       }
 265
 266       memset(p, 0, count);
 267       byteSwap(in, 14);
 268
 269       // Append length in bits and transform
 270       in[14] = bytes[0] << 3;
 271       in[15] = bytes[1] << 3 | bytes[0] >> 29;
 272       MD5Transform(buf,in);
 273       byteSwap(buf,4);
 274       Done = true;
 275    }
 276
 277    MD5SumValue V;
 278    V.Set((unsigned char *)buf);
 279    return V;
 280 }
 281                                                                         /*}}}*/