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lib/md5.c

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00001 
00021 #include "system.h"
00022 #include "md5.h"
00023 #include "debug.h"
00024 
00025 static int _ie = 0x44332211;
00026 static union _mendian { int i; char b[4]; } *_endian = (union _mendian *)&_ie;
00027 #define IS_BIG_ENDIAN()         (_endian->b[0] == '\x44')
00028 #define IS_LITTLE_ENDIAN()      (_endian->b[0] == '\x11')
00029 
00030 void byteReverse(unsigned char *buf, unsigned longs);
00031 
00032 /*
00033  * Note: this code is harmless on little-endian machines.
00034  */
00035 void byteReverse(unsigned char *buf, unsigned longs)
00036 {
00037     uint32 t;
00038     do {
00039         t = (uint32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
00040             ((unsigned) buf[1] << 8 | buf[0]);
00041         *(uint32 *) buf = t;
00042         buf += 4;
00043     } while (--longs);
00044 }
00045 
00046 /*
00047  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
00048  * initialization constants.
00049  */
00050 void rpmMD5Init(struct MD5Context *ctx, int brokenEndian)
00051 {
00052     ctx->buf[0] = 0x67452301;
00053     ctx->buf[1] = 0xefcdab89;
00054     ctx->buf[2] = 0x98badcfe;
00055     ctx->buf[3] = 0x10325476;
00056 
00057     ctx->bits[0] = 0;
00058     ctx->bits[1] = 0;
00059 
00060     if (IS_BIG_ENDIAN()) {      /* XXX was ifdef WORDS_BIGENDIAN */
00061         if (brokenEndian) {
00062             ctx->doByteReverse = 0;
00063         } else {
00064             ctx->doByteReverse = 1;
00065         }
00066     } else {
00067         ctx->doByteReverse = 0;
00068     }
00069 }
00070 
00071 /*
00072  * Update context to reflect the concatenation of another buffer full
00073  * of bytes.
00074  */
00075 void rpmMD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
00076 {
00077     uint32 t;
00078 
00079     /* Update bitcount */
00080 
00081     t = ctx->bits[0];
00082     if ((ctx->bits[0] = t + ((uint32) len << 3)) < t)
00083         ctx->bits[1]++;         /* Carry from low to high */
00084     ctx->bits[1] += len >> 29;
00085 
00086     t = (t >> 3) & 0x3f;        /* Bytes already in shsInfo->data */
00087 
00088     /* Handle any leading odd-sized chunks */
00089 
00090     if (t) {
00091         unsigned char *p = (unsigned char *) ctx->in + t;
00092 
00093         t = 64 - t;
00094         if (len < t) {
00095             memcpy(p, buf, len);
00096             return;
00097         }
00098         memcpy(p, buf, t);
00099         if (ctx->doByteReverse)
00100             byteReverse(ctx->in, 16);
00101         rpmMD5Transform(ctx->buf, (uint32 *) ctx->in);
00102         buf += t;
00103         len -= t;
00104     }
00105     /* Process data in 64-byte chunks */
00106 
00107     while (len >= 64) {
00108         memcpy(ctx->in, buf, 64);
00109         if (ctx->doByteReverse)
00110             byteReverse(ctx->in, 16);
00111         rpmMD5Transform(ctx->buf, (uint32 *) ctx->in);
00112         buf += 64;
00113         len -= 64;
00114     }
00115 
00116     /* Handle any remaining bytes of data. */
00117 
00118     memcpy(ctx->in, buf, len);
00119 }
00120 
00121 /*
00122  * Final wrapup - pad to 64-byte boundary with the bit pattern 
00123  * 1 0* (64-bit count of bits processed, MSB-first)
00124  */
00125 void rpmMD5Final(unsigned char digest[16], struct MD5Context *ctx)
00126 {
00127     unsigned count;
00128     unsigned char *p;
00129 
00130     /* Compute number of bytes mod 64 */
00131     count = (ctx->bits[0] >> 3) & 0x3F;
00132 
00133     /* Set the first char of padding to 0x80.  This is safe since there is
00134        always at least one byte free */
00135     p = ctx->in + count;
00136     *p++ = 0x80;
00137 
00138     /* Bytes of padding needed to make 64 bytes */
00139     count = 64 - 1 - count;
00140 
00141     /* Pad out to 56 mod 64 */
00142     if (count < 8) {
00143         /* Two lots of padding:  Pad the first block to 64 bytes */
00144         memset(p, 0, count);
00145         if (ctx->doByteReverse)
00146             byteReverse(ctx->in, 16);
00147         rpmMD5Transform(ctx->buf, (uint32 *) ctx->in);
00148 
00149         /* Now fill the next block with 56 bytes */
00150         memset(ctx->in, 0, 56);
00151     } else {
00152         /* Pad block to 56 bytes */
00153         memset(p, 0, count - 8);
00154     }
00155     if (ctx->doByteReverse)
00156         byteReverse(ctx->in, 14);
00157 
00158     /* Append length in bits and transform */
00159     ((uint32 *) ctx->in)[14] = ctx->bits[0];
00160     ((uint32 *) ctx->in)[15] = ctx->bits[1];
00161 
00162     rpmMD5Transform(ctx->buf, (uint32 *) ctx->in);
00163     if (ctx->doByteReverse)
00164         byteReverse((unsigned char *) ctx->buf, 4);
00165     memcpy(digest, ctx->buf, 16);
00166     memset(ctx, 0, sizeof(ctx));        /* In case it's sensitive */
00167 }
00168 
00169 /* The four core functions - F1 is optimized somewhat */
00170 
00171 /* #define F1(x, y, z) (x & y | ~x & z) */
00172 #define F1(x, y, z) (z ^ (x & (y ^ z)))
00173 #define F2(x, y, z) F1(z, x, y)
00174 #define F3(x, y, z) (x ^ y ^ z)
00175 #define F4(x, y, z) (y ^ (x | ~z))
00176 
00177 /* This is the central step in the MD5 algorithm. */
00178 #define MD5STEP(f, w, x, y, z, data, s) \
00179         ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
00180 
00181 /*
00182  * The core of the MD5 algorithm, this alters an existing MD5 hash to
00183  * reflect the addition of 16 longwords of new data.  rpmMD5Update blocks
00184  * the data and converts bytes into longwords for this routine.
00185  */
00186 void rpmMD5Transform(uint32 buf[4], uint32 const in[16])
00187 {
00188     register uint32 a, b, c, d;
00189 
00190     a = buf[0];
00191     b = buf[1];
00192     c = buf[2];
00193     d = buf[3];
00194 
00195     MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
00196     MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
00197     MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
00198     MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
00199     MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
00200     MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
00201     MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
00202     MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
00203     MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
00204     MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
00205     MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
00206     MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
00207     MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
00208     MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
00209     MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
00210     MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
00211 
00212     MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
00213     MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
00214     MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
00215     MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
00216     MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
00217     MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
00218     MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
00219     MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
00220     MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
00221     MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
00222     MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
00223     MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
00224     MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
00225     MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
00226     MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
00227     MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
00228 
00229     MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
00230     MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
00231     MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
00232     MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
00233     MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
00234     MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
00235     MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
00236     MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
00237     MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
00238     MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
00239     MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
00240     MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
00241     MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
00242     MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
00243     MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
00244     MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
00245 
00246     MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
00247     MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
00248     MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
00249     MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
00250     MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
00251     MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
00252     MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
00253     MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
00254     MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
00255     MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
00256     MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
00257     MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
00258     MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
00259     MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
00260     MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
00261     MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
00262 
00263     buf[0] += a;
00264     buf[1] += b;
00265     buf[2] += c;
00266     buf[3] += d;
00267 }
00268 

Generated at Sun Apr 8 18:43:00 2001 for rpm by doxygen1.2.3 written by Dimitri van Heesch, © 1997-2000