fs/cifs/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 cifs_MD5_init, call cifs_MD5_update as
  14  * needed on buffers full of bytes, and then call cifs_MD5_final, 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    and to fit the cifs vfs by
  21    Steve French sfrench@us.ibm.com */
  22
  23 #include <linux/string.h>
  24 #include "md5.h"
  25
  26 static void MD5Transform(__u32 buf[4], __u32 const in[16]);
  27
  28 /*
  29  * Note: this code is harmless on little-endian machines.
  30  */
  31 static void
  32 byteReverse(unsigned char *buf, unsigned longs)
  33 {
  34         __u32 t;
  35         do {
  36                 t = (__u32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
  37                     ((unsigned) buf[1] << 8 | buf[0]);
  38                 *(__u32 *) buf = t;
  39                 buf += 4;
  40         } while (--longs);
  41 }
  42
  43 /*
  44  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  45  * initialization constants.
  46  */
  47 void
  48 cifs_MD5_init(struct MD5Context *ctx)
  49 {
  50         ctx->buf[0] = 0x67452301;
  51         ctx->buf[1] = 0xefcdab89;
  52         ctx->buf[2] = 0x98badcfe;
  53         ctx->buf[3] = 0x10325476;
  54
  55         ctx->bits[0] = 0;
  56         ctx->bits[1] = 0;
  57 }
  58
  59 /*
  60  * Update context to reflect the concatenation of another buffer full
  61  * of bytes.
  62  */
  63 void
  64 cifs_MD5_update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
  65 {
  66         register __u32 t;
  67
  68         /* Update bitcount */
  69
  70         t = ctx->bits[0];
  71         if ((ctx->bits[0] = t + ((__u32) len << 3)) < t)
  72                 ctx->bits[1]++; /* Carry from low to high */
  73         ctx->bits[1] += len >> 29;
  74
  75         t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */
  76
  77         /* Handle any leading odd-sized chunks */
  78
  79         if (t) {
  80                 unsigned char *p = (unsigned char *) ctx->in + t;
  81
  82                 t = 64 - t;
  83                 if (len < t) {
  84                         memmove(p, buf, len);
  85                         return;
  86                 }
  87                 memmove(p, buf, t);
  88                 byteReverse(ctx->in, 16);
  89                 MD5Transform(ctx->buf, (__u32 *) ctx->in);
  90                 buf += t;
  91                 len -= t;
  92         }
  93         /* Process data in 64-byte chunks */
  94
  95         while (len >= 64) {
  96                 memmove(ctx->in, buf, 64);
  97                 byteReverse(ctx->in, 16);
  98                 MD5Transform(ctx->buf, (__u32 *) ctx->in);
  99                 buf += 64;
 100                 len -= 64;
 101         }
 102
 103         /* Handle any remaining bytes of data. */
 104
 105         memmove(ctx->in, buf, len);
 106 }
 107
 108 /*
 109  * Final wrapup - pad to 64-byte boundary with the bit pattern
 110  * 1 0* (64-bit count of bits processed, MSB-first)
 111  */
 112 void
 113 cifs_MD5_final(unsigned char digest[16], struct MD5Context *ctx)
 114 {
 115         unsigned int count;
 116         unsigned char *p;
 117
 118         /* Compute number of bytes mod 64 */
 119         count = (ctx->bits[0] >> 3) & 0x3F;
 120
 121         /* Set the first char of padding to 0x80.  This is safe since there is
 122            always at least one byte free */
 123         p = ctx->in + count;
 124         *p++ = 0x80;
 125
 126         /* Bytes of padding needed to make 64 bytes */
 127         count = 64 - 1 - count;
 128
 129         /* Pad out to 56 mod 64 */
 130         if (count < 8) {
 131                 /* Two lots of padding:  Pad the first block to 64 bytes */
 132                 memset(p, 0, count);
 133                 byteReverse(ctx->in, 16);
 134                 MD5Transform(ctx->buf, (__u32 *) ctx->in);
 135
 136                 /* Now fill the next block with 56 bytes */
 137                 memset(ctx->in, 0, 56);
 138         } else {
 139                 /* Pad block to 56 bytes */
 140                 memset(p, 0, count - 8);
 141         }
 142         byteReverse(ctx->in, 14);
 143
 144         /* Append length in bits and transform */
 145         ((__u32 *) ctx->in)[14] = ctx->bits[0];
 146         ((__u32 *) ctx->in)[15] = ctx->bits[1];
 147
 148         MD5Transform(ctx->buf, (__u32 *) ctx->in);
 149         byteReverse((unsigned char *) ctx->buf, 4);
 150         memmove(digest, ctx->buf, 16);
 151         memset(ctx, 0, sizeof(*ctx));   /* In case it's sensitive */
 152 }
 153
 154 /* The four core functions - F1 is optimized somewhat */
 155
 156 /* #define F1(x, y, z) (x & y | ~x & z) */
 157 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 158 #define F2(x, y, z) F1(z, x, y)
 159 #define F3(x, y, z) (x ^ y ^ z)
 160 #define F4(x, y, z) (y ^ (x | ~z))
 161
 162 /* This is the central step in the MD5 algorithm. */
 163 #define MD5STEP(f, w, x, y, z, data, s) \
 164         (w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x)
 165
 166 /*
 167  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 168  * reflect the addition of 16 longwords of new data.  cifs_MD5_update blocks
 169  * the data and converts bytes into longwords for this routine.
 170  */
 171 static void
 172 MD5Transform(__u32 buf[4], __u32 const in[16])
 173 {
 174         register __u32 a, b, c, d;
 175
 176         a = buf[0];
 177         b = buf[1];
 178         c = buf[2];
 179         d = buf[3];
 180
 181         MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 182         MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 183         MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 184         MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 185         MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 186         MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 187         MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 188         MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 189         MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 190         MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 191         MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 192         MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 193         MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 194         MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 195         MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 196         MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 197
 198         MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 199         MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 200         MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 201         MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 202         MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 203         MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 204         MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 205         MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 206         MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 207         MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 208         MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 209         MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 210         MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 211         MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 212         MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 213         MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 214
 215         MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 216         MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 217         MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 218         MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 219         MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 220         MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 221         MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 222         MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 223         MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 224         MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 225         MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 226         MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 227         MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 228         MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 229         MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 230         MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 231
 232         MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 233         MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 234         MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 235         MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 236         MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 237         MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 238         MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 239         MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 240         MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 241         MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 242         MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 243         MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 244         MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 245         MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 246         MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 247         MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 248
 249         buf[0] += a;
 250         buf[1] += b;
 251         buf[2] += c;
 252         buf[3] += d;
 253 }
 254
 255 #if 0   /* currently unused */
 256 /***********************************************************************
 257  the rfc 2104 version of hmac_md5 initialisation.
 258 ***********************************************************************/
 259 static void
 260 hmac_md5_init_rfc2104(unsigned char *key, int key_len,
 261                       struct HMACMD5Context *ctx)
 262 {
 263         int i;
 264
 265         /* if key is longer than 64 bytes reset it to key=MD5(key) */
 266         if (key_len > 64) {
 267                 unsigned char tk[16];
 268                 struct MD5Context tctx;
 269
 270                 cifs_MD5_init(&tctx);
 271                 cifs_MD5_update(&tctx, key, key_len);
 272                 cifs_MD5_final(tk, &tctx);
 273
 274                 key = tk;
 275                 key_len = 16;
 276         }
 277
 278         /* start out by storing key in pads */
 279         memset(ctx->k_ipad, 0, sizeof(ctx->k_ipad));
 280         memset(ctx->k_opad, 0, sizeof(ctx->k_opad));
 281         memcpy(ctx->k_ipad, key, key_len);
 282         memcpy(ctx->k_opad, key, key_len);
 283
 284         /* XOR key with ipad and opad values */
 285         for (i = 0; i < 64; i++) {
 286                 ctx->k_ipad[i] ^= 0x36;
 287                 ctx->k_opad[i] ^= 0x5c;
 288         }
 289
 290         cifs_MD5_init(&ctx->ctx);
 291         cifs_MD5_update(&ctx->ctx, ctx->k_ipad, 64);
 292 }
 293 #endif
 294
 295 /***********************************************************************
 296  the microsoft version of hmac_md5 initialisation.
 297 ***********************************************************************/
 298 void
 299 hmac_md5_init_limK_to_64(const unsigned char *key, int key_len,
 300                          struct HMACMD5Context *ctx)
 301 {
 302         int i;
 303
 304         /* if key is longer than 64 bytes truncate it */
 305         if (key_len > 64)
 306                 key_len = 64;
 307
 308         /* start out by storing key in pads */
 309         memset(ctx->k_ipad, 0, sizeof(ctx->k_ipad));
 310         memset(ctx->k_opad, 0, sizeof(ctx->k_opad));
 311         memcpy(ctx->k_ipad, key, key_len);
 312         memcpy(ctx->k_opad, key, key_len);
 313
 314         /* XOR key with ipad and opad values */
 315         for (i = 0; i < 64; i++) {
 316                 ctx->k_ipad[i] ^= 0x36;
 317                 ctx->k_opad[i] ^= 0x5c;
 318         }
 319
 320         cifs_MD5_init(&ctx->ctx);
 321         cifs_MD5_update(&ctx->ctx, ctx->k_ipad, 64);
 322 }
 323
 324 /***********************************************************************
 325  update hmac_md5 "inner" buffer
 326 ***********************************************************************/
 327 void
 328 hmac_md5_update(const unsigned char *text, int text_len,
 329                 struct HMACMD5Context *ctx)
 330 {
 331         cifs_MD5_update(&ctx->ctx, text, text_len);     /* then text of datagram */
 332 }
 333
 334 /***********************************************************************
 335  finish off hmac_md5 "inner" buffer and generate outer one.
 336 ***********************************************************************/
 337 void
 338 hmac_md5_final(unsigned char *digest, struct HMACMD5Context *ctx)
 339 {
 340         struct MD5Context ctx_o;
 341
 342         cifs_MD5_final(digest, &ctx->ctx);
 343
 344         cifs_MD5_init(&ctx_o);
 345         cifs_MD5_update(&ctx_o, ctx->k_opad, 64);
 346         cifs_MD5_update(&ctx_o, digest, 16);
 347         cifs_MD5_final(digest, &ctx_o);
 348 }
 349
 350 /***********************************************************
 351  single function to calculate an HMAC MD5 digest from data.
 352  use the microsoft hmacmd5 init method because the key is 16 bytes.
 353 ************************************************************/
 354 #if 0 /* currently unused */
 355 static void
 356 hmac_md5(unsigned char key[16], unsigned char *data, int data_len,
 357          unsigned char *digest)
 358 {
 359         struct HMACMD5Context ctx;
 360         hmac_md5_init_limK_to_64(key, 16, &ctx);
 361         if (data_len != 0)
 362                 hmac_md5_update(data, data_len, &ctx);
 363
 364         hmac_md5_final(digest, &ctx);
 365 }
 366 #endif