LXR linux/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
  26static void MD5Transform(__u32 buf[4], __u32 const in[16]);
  27
  28/*
  29 * Note: this code is harmless on little-endian machines.
  30 */
  31static void
  32byteReverse(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 */
  47void
  48cifs_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 */
  63void
  64cifs_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 */
 112void
 113cifs_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 */
 171static void
 172MD5Transform(__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***********************************************************************/
 259static void
 260hmac_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***********************************************************************/
 298void
 299hmac_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***********************************************************************/
 327void
 328hmac_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***********************************************************************/
 337void
 338hmac_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 */
 355static void
 356hmac_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
 367