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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 {
00027 /*@unused@*/ int i;
00028     char b[4];
00029 } *_endian = (union _mendian *)&_ie;
00030 #define IS_BIG_ENDIAN()         (_endian->b[0] == '\x44')
00031 #define IS_LITTLE_ENDIAN()      (_endian->b[0] == '\x11')
00032 
00033 /*
00034  * Note: this code is harmless on little-endian machines.
00035  */
00036 static void byteReverse(unsigned char *buf, unsigned longs)
00037         /*@modifies *buf @*/
00038 {
00039     uint32 t;
00040     do {
00041         t = (uint32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
00042             ((unsigned) buf[1] << 8 | buf[0]);
00043         *(uint32 *) buf = t;
00044         buf += 4;
00045     } while (--longs);
00046 }
00047 
00048 /*
00049  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
00050  * initialization constants.
00051  */
00052 void rpmMD5Init(struct MD5Context *ctx, int brokenEndian)
00053 {
00054     ctx->buf[0] = 0x67452301;
00055     ctx->buf[1] = 0xefcdab89;
00056     ctx->buf[2] = 0x98badcfe;
00057     ctx->buf[3] = 0x10325476;
00058 
00059     ctx->bits[0] = 0;
00060     ctx->bits[1] = 0;
00061 
00062     if (IS_BIG_ENDIAN()) {      /* XXX was ifdef WORDS_BIGENDIAN */
00063         if (brokenEndian) {
00064             ctx->doByteReverse = 0;
00065         } else {
00066             ctx->doByteReverse = 1;
00067         }
00068     } else {
00069         ctx->doByteReverse = 0;
00070     }
00071 }
00072 
00073 /*
00074  * Update context to reflect the concatenation of another buffer full
00075  * of bytes.
00076  */
00077 void rpmMD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
00078 {
00079     uint32 t;
00080 
00081     /* Update bitcount */
00082 
00083     t = ctx->bits[0];
00084     if ((ctx->bits[0] = t + ((uint32) len << 3)) < t)
00085         ctx->bits[1]++;         /* Carry from low to high */
00086     ctx->bits[1] += len >> 29;
00087 
00088     t = (t >> 3) & 0x3f;        /* Bytes already in shsInfo->data */
00089 
00090     /* Handle any leading odd-sized chunks */
00091 
00092     if (t) {
00093         unsigned char *p = (unsigned char *) ctx->in + t;
00094 
00095         t = 64 - t;
00096         if (len < t) {
00097             memcpy(p, buf, len);
00098             return;
00099         }
00100         memcpy(p, buf, t);
00101         if (ctx->doByteReverse)
00102             byteReverse(ctx->in, 16);
00103         rpmMD5Transform(ctx->buf, (uint32 *) ctx->in);
00104         buf += t;
00105         len -= t;
00106     }
00107     /* Process data in 64-byte chunks */
00108 
00109     while (len >= 64) {
00110         memcpy(ctx->in, buf, 64);
00111         if (ctx->doByteReverse)
00112             byteReverse(ctx->in, 16);
00113         rpmMD5Transform(ctx->buf, (uint32 *) ctx->in);
00114         buf += 64;
00115         len -= 64;
00116     }
00117 
00118     /* Handle any remaining bytes of data. */
00119 
00120     memcpy(ctx->in, buf, len);
00121 }
00122 
00123 /*
00124  * Final wrapup - pad to 64-byte boundary with the bit pattern 
00125  * 1 0* (64-bit count of bits processed, MSB-first)
00126  */
00127 /*@-fixedformalarray@*/
00128 void rpmMD5Final(unsigned char digest[16], struct MD5Context *ctx)
00129 /*@=fixedformalarray@*/
00130 {
00131     unsigned count;
00132     unsigned char *p;
00133 
00134     /* Compute number of bytes mod 64 */
00135     count = (ctx->bits[0] >> 3) & 0x3F;
00136 
00137     /* Set the first char of padding to 0x80.  This is safe since there is
00138        always at least one byte free */
00139     p = ctx->in + count;
00140     *p++ = 0x80;
00141 
00142     /* Bytes of padding needed to make 64 bytes */
00143     count = 64 - 1 - count;
00144 
00145     /* Pad out to 56 mod 64 */
00146     if (count < 8) {
00147         /* Two lots of padding:  Pad the first block to 64 bytes */
00148         memset(p, 0, count);
00149         if (ctx->doByteReverse)
00150             byteReverse(ctx->in, 16);
00151         rpmMD5Transform(ctx->buf, (uint32 *) ctx->in);
00152 
00153         /* Now fill the next block with 56 bytes */
00154         memset(ctx->in, 0, 56);
00155     } else {
00156         /* Pad block to 56 bytes */
00157         memset(p, 0, count - 8);
00158     }
00159     if (ctx->doByteReverse)
00160         byteReverse(ctx->in, 14);
00161 
00162     /* Append length in bits and transform */
00163     ((uint32 *) ctx->in)[14] = ctx->bits[0];
00164     ((uint32 *) ctx->in)[15] = ctx->bits[1];
00165 
00166     rpmMD5Transform(ctx->buf, (uint32 *) ctx->in);
00167     if (ctx->doByteReverse)
00168         byteReverse((unsigned char *) ctx->buf, 4);
00169     memcpy(digest, ctx->buf, 16);
00170     memset(ctx, 0, sizeof(ctx));        /* In case it's sensitive */
00171 }
00172 
00173 /* The four core functions - F1 is optimized somewhat */
00174 
00175 /* #define F1(x, y, z) (x & y | ~x & z) */
00176 #define F1(x, y, z) (z ^ (x & (y ^ z)))
00177 #define F2(x, y, z) F1(z, x, y)
00178 #define F3(x, y, z) (x ^ y ^ z)
00179 #define F4(x, y, z) (y ^ (x | ~z))
00180 
00181 /* This is the central step in the MD5 algorithm. */
00182 #define MD5STEP(f, w, x, y, z, data, s) \
00183         ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
00184 
00185 /*
00186  * The core of the MD5 algorithm, this alters an existing MD5 hash to
00187  * reflect the addition of 16 longwords of new data.  rpmMD5Update blocks
00188  * the data and converts bytes into longwords for this routine.
00189  */
00190 /*@-fixedformalarray@*/
00191 void rpmMD5Transform(uint32 buf[4], uint32 const in[16])
00192 /*@=fixedformalarray@*/
00193 {
00194     register uint32 a, b, c, d;
00195 
00196     a = buf[0];
00197     b = buf[1];
00198     c = buf[2];
00199     d = buf[3];
00200 
00201     MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
00202     MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
00203     MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
00204     MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
00205     MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
00206     MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
00207     MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
00208     MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
00209     MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
00210     MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
00211     MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
00212     MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
00213     MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
00214     MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
00215     MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
00216     MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
00217 
00218     MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
00219     MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
00220     MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
00221     MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
00222     MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
00223     MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
00224     MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
00225     MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
00226     MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
00227     MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
00228     MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
00229     MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
00230     MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
00231     MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
00232     MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
00233     MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
00234 
00235     MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
00236     MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
00237     MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
00238     MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
00239     MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
00240     MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
00241     MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
00242     MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
00243     MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
00244     MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
00245     MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
00246     MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
00247     MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
00248     MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
00249     MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
00250     MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
00251 
00252     MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
00253     MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
00254     MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
00255     MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
00256     MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
00257     MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
00258     MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
00259     MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
00260     MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
00261     MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
00262     MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
00263     MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
00264     MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
00265     MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
00266     MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
00267     MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
00268 
00269     buf[0] += a;
00270     buf[1] += b;
00271     buf[2] += c;
00272     buf[3] += d;
00273 }
00274 

Generated at Wed Mar 27 03:56:49 2002 for rpm by doxygen1.2.8.1 written by Dimitri van Heesch, © 1997-2001