release/src/router/dhcpv6/auth.c

   1 /*      $KAME: auth.c,v 1.4 2004/09/07 05:03:02 jinmei Exp $    */
   2
   3 /*
   4  * Copyright (C) 2004 WIDE Project.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the project nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
  34  * Copyright (C) 2000, 2001  Internet Software Consortium.
  35  *
  36  * Permission to use, copy, modify, and distribute this software for any
  37  * purpose with or without fee is hereby granted, provided that the above
  38  * copyright notice and this permission notice appear in all copies.
  39  *
  40  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  41  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  42  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  43  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  44  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  45  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  46  * PERFORMANCE OF THIS SOFTWARE.
  47  */
  48 #include <sys/param.h>
  49 #include <sys/types.h>
  50 #include <sys/socket.h>
  51 #include <sys/queue.h>
  52 #if TIME_WITH_SYS_TIME
  53 # include <sys/time.h>
  54 # include <time.h>
  55 #else
  56 # if HAVE_SYS_TIME_H
  57 #  include <sys/time.h>
  58 # else
  59 #  include <time.h>
  60 # endif
  61 #endif
  62
  63 #include <netinet/in.h>
  64
  65 #include <syslog.h>
  66 #include <string.h>
  67 #include <errno.h>
  68
  69 #include <dhcp6.h>
  70 #include <config.h>
  71 #include <common.h>
  72 #include <auth.h>
  73
  74 #define PADLEN 64
  75 #define IPAD 0x36
  76 #define OPAD 0x5C
  77
  78 #define HMACMD5_KEYLENGTH 64
  79
  80 typedef struct {
  81         u_int32_t buf[4];
  82         u_int32_t bytes[2];
  83         u_int32_t in[16];
  84 } md5_t;
  85
  86 typedef struct {
  87         md5_t md5ctx;
  88         unsigned char key[HMACMD5_KEYLENGTH];
  89 } hmacmd5_t;
  90
  91 static void hmacmd5_init __P((hmacmd5_t *, const unsigned char *,
  92     unsigned int));
  93 static void hmacmd5_invalidate __P((hmacmd5_t *));
  94 static void hmacmd5_update __P((hmacmd5_t *, const unsigned char *,
  95     unsigned int));
  96 static void hmacmd5_sign __P((hmacmd5_t *, unsigned char *));
  97 static int hmacmd5_verify __P((hmacmd5_t *, unsigned char *));
  98
  99 static void md5_init __P((md5_t *));
 100 static void md5_invalidate __P((md5_t *));
 101 static void md5_final __P((md5_t *, unsigned char *));
 102 static void md5_update __P((md5_t *, const unsigned char *, unsigned int));
 103
 104 int
 105 dhcp6_validate_key(key)
 106         struct keyinfo *key;
 107 {
 108         time_t now;
 109
 110         if (key->expire == 0)   /* never expire */
 111                 return (0);
 112
 113         if (time(&now) == -1)
 114                 return (-1);    /* treat it as expiration (XXX) */
 115
 116         if (now > key->expire)
 117                 return (-1);
 118
 119         return (0);
 120 }
 121
 122 int
 123 dhcp6_calc_mac(buf, len, proto, alg, off, key)
 124         char *buf;
 125         size_t len, off;
 126         int proto, alg;
 127         struct keyinfo *key;
 128 {
 129         hmacmd5_t ctx;
 130         unsigned char digest[MD5_DIGESTLENGTH];
 131
 132         /* right now, we don't care about the protocol */
 133
 134         if (alg != DHCP6_AUTHALG_HMACMD5)
 135                 return (-1);
 136
 137         if (off + MD5_DIGESTLENGTH > len) {
 138                 /*
 139                  * this should be assured by the caller, but check it here
 140                  * for safety.
 141                  */
 142                 return (-1);
 143         }
 144
 145         hmacmd5_init(&ctx, key->secret, key->secretlen);
 146         hmacmd5_update(&ctx, buf, len);
 147         hmacmd5_sign(&ctx, digest);
 148
 149         memcpy(buf + off, digest, MD5_DIGESTLENGTH);
 150
 151         return (0);
 152 }
 153
 154 int
 155 dhcp6_verify_mac(buf, len, proto, alg, off, key)
 156         char *buf;
 157         ssize_t len;
 158         int proto, alg;
 159         size_t off;
 160         struct keyinfo *key;
 161 {
 162         hmacmd5_t ctx;
 163         unsigned char digest[MD5_DIGESTLENGTH];
 164         int result;
 165
 166         /* right now, we don't care about the protocol */
 167
 168         if (alg != DHCP6_AUTHALG_HMACMD5)
 169                 return (-1);
 170
 171         if (off + MD5_DIGESTLENGTH > len)
 172                 return (-1);
 173
 174         /*
 175          * Copy the MAC value and clear the field.
 176          * XXX: should we make a local working copy?
 177          */
 178         memcpy(digest, buf + off, sizeof(digest));
 179         memset(buf + off, 0, sizeof(digest));
 180
 181         hmacmd5_init(&ctx, key->secret, key->secretlen);
 182         hmacmd5_update(&ctx, buf, len);
 183         result = hmacmd5_verify(&ctx, digest);
 184
 185         /* copy back the digest value (XXX) */
 186         memcpy(buf + off, digest, sizeof(digest));
 187
 188         return (result);
 189 }
 190
 191 /*
 192  * This code implements the HMAC-MD5 keyed hash algorithm
 193  * described in RFC 2104.
 194  */
 195 /*
 196  * Start HMAC-MD5 process.  Initialize an md5 context and digest the key.
 197  */
 198 static void
 199 hmacmd5_init(hmacmd5_t *ctx, const unsigned char *key, unsigned int len)
 200 {
 201         unsigned char ipad[PADLEN];
 202         int i;
 203
 204         memset(ctx->key, 0, sizeof(ctx->key));
 205         if (len > sizeof(ctx->key)) {
 206                 md5_t md5ctx;
 207                 md5_init(&md5ctx);
 208                 md5_update(&md5ctx, key, len);
 209                 md5_final(&md5ctx, ctx->key);
 210         } else
 211                 memcpy(ctx->key, key, len);
 212
 213         md5_init(&ctx->md5ctx);
 214         memset(ipad, IPAD, sizeof(ipad));
 215         for (i = 0; i < PADLEN; i++)
 216                 ipad[i] ^= ctx->key[i];
 217         md5_update(&ctx->md5ctx, ipad, sizeof(ipad));
 218 }
 219
 220 static void
 221 hmacmd5_invalidate(hmacmd5_t *ctx)
 222 {
 223         md5_invalidate(&ctx->md5ctx);
 224         memset(ctx->key, 0, sizeof(ctx->key));
 225         memset(ctx, 0, sizeof(ctx));
 226 }
 227
 228 /*
 229  * Update context to reflect the concatenation of another buffer full
 230  * of bytes.
 231  */
 232 static void
 233 hmacmd5_update(hmacmd5_t *ctx, const unsigned char *buf, unsigned int len)
 234 {
 235         md5_update(&ctx->md5ctx, buf, len);
 236 }
 237
 238 /*
 239  * Compute signature - finalize MD5 operation and reapply MD5.
 240  */
 241 static void
 242 hmacmd5_sign(hmacmd5_t *ctx, unsigned char *digest)
 243 {
 244         unsigned char opad[PADLEN];
 245         int i;
 246
 247         md5_final(&ctx->md5ctx, digest);
 248
 249         memset(opad, OPAD, sizeof(opad));
 250         for (i = 0; i < PADLEN; i++)
 251                 opad[i] ^= ctx->key[i];
 252
 253         md5_init(&ctx->md5ctx);
 254         md5_update(&ctx->md5ctx, opad, sizeof(opad));
 255         md5_update(&ctx->md5ctx, digest, MD5_DIGESTLENGTH);
 256         md5_final(&ctx->md5ctx, digest);
 257         hmacmd5_invalidate(ctx);
 258 }
 259
 260 /*
 261  * Verify signature - finalize MD5 operation and reapply MD5, then
 262  * compare to the supplied digest.
 263  */
 264 static int
 265 hmacmd5_verify(hmacmd5_t *ctx, unsigned char *digest) {
 266         unsigned char newdigest[MD5_DIGESTLENGTH];
 267
 268         hmacmd5_sign(ctx, newdigest);
 269         return (memcmp(digest, newdigest, MD5_DIGESTLENGTH));
 270 }
 271
 272 /*
 273  * This code implements the MD5 message-digest algorithm.
 274  * The algorithm is due to Ron Rivest.  This code was
 275  * written by Colin Plumb in 1993, no copyright is claimed.
 276  * This code is in the public domain; do with it what you wish.
 277  *
 278  * Equivalent code is available from RSA Data Security, Inc.
 279  * This code has been tested against that, and is equivalent,
 280  * except that you don't need to include two pages of legalese
 281  * with every copy.
 282  *
 283  * To compute the message digest of a chunk of bytes, declare an
 284  * MD5Context structure, pass it to MD5Init, call MD5Update as
 285  * needed on buffers full of bytes, and then call MD5Final, which
 286  * will fill a supplied 16-byte array with the digest.
 287  */
 288
 289 static void
 290 byteSwap(u_int32_t *buf, unsigned words)
 291 {
 292         unsigned char *p = (unsigned char *)buf;
 293
 294         do {
 295                 *buf++ = (u_int32_t)((unsigned)p[3] << 8 | p[2]) << 16 |
 296                         ((unsigned)p[1] << 8 | p[0]);
 297                 p += 4;
 298         } while (--words);
 299 }
 300
 301 /*
 302  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 303  * initialization constants.
 304  */
 305 static void
 306 md5_init(md5_t *ctx)
 307 {
 308         ctx->buf[0] = 0x67452301;
 309         ctx->buf[1] = 0xefcdab89;
 310         ctx->buf[2] = 0x98badcfe;
 311         ctx->buf[3] = 0x10325476;
 312
 313         ctx->bytes[0] = 0;
 314         ctx->bytes[1] = 0;
 315 }
 316
 317 static void
 318 md5_invalidate(md5_t *ctx)
 319 {
 320         memset(ctx, 0, sizeof(md5_t));
 321 }
 322
 323 /* The four core functions - F1 is optimized somewhat */
 324
 325 /* #define F1(x, y, z) (x & y | ~x & z) */
 326 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 327 #define F2(x, y, z) F1(z, x, y)
 328 #define F3(x, y, z) (x ^ y ^ z)
 329 #define F4(x, y, z) (y ^ (x | ~z))
 330
 331 /* This is the central step in the MD5 algorithm. */
 332 #define MD5STEP(f,w,x,y,z,in,s) \
 333          (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)
 334
 335 /*
 336  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 337  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 338  * the data and converts bytes into longwords for this routine.
 339  */
 340 static void
 341 transform(u_int32_t buf[4], u_int32_t const in[16]) {
 342         register u_int32_t a, b, c, d;
 343
 344         a = buf[0];
 345         b = buf[1];
 346         c = buf[2];
 347         d = buf[3];
 348
 349         MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 350         MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 351         MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 352         MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 353         MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 354         MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 355         MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 356         MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 357         MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 358         MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 359         MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 360         MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 361         MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 362         MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 363         MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 364         MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 365
 366         MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 367         MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 368         MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 369         MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 370         MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 371         MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 372         MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 373         MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 374         MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 375         MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 376         MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 377         MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 378         MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 379         MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 380         MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 381         MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 382
 383         MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 384         MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 385         MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 386         MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 387         MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 388         MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 389         MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 390         MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 391         MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 392         MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 393         MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 394         MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 395         MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 396         MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 397         MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 398         MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 399
 400         MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 401         MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 402         MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 403         MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 404         MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 405         MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 406         MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 407         MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 408         MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 409         MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 410         MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 411         MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 412         MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 413         MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 414         MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 415         MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 416
 417         buf[0] += a;
 418         buf[1] += b;
 419         buf[2] += c;
 420         buf[3] += d;
 421 }
 422
 423 /*
 424  * Update context to reflect the concatenation of another buffer full
 425  * of bytes.
 426  */
 427 static void
 428 md5_update(md5_t *ctx, const unsigned char *buf, unsigned int len)
 429 {
 430         u_int32_t t;
 431
 432         /* Update byte count */
 433
 434         t = ctx->bytes[0];
 435         if ((ctx->bytes[0] = t + len) < t)
 436                 ctx->bytes[1]++;        /* Carry from low to high */
 437
 438         t = 64 - (t & 0x3f);    /* Space available in ctx->in (at least 1) */
 439         if (t > len) {
 440                 memcpy((unsigned char *)ctx->in + 64 - t, buf, len);
 441                 return;
 442         }
 443         /* First chunk is an odd size */
 444         memcpy((unsigned char *)ctx->in + 64 - t, buf, t);
 445         byteSwap(ctx->in, 16);
 446         transform(ctx->buf, ctx->in);
 447         buf += t;
 448         len -= t;
 449
 450         /* Process data in 64-byte chunks */
 451         while (len >= 64) {
 452                 memcpy(ctx->in, buf, 64);
 453                 byteSwap(ctx->in, 16);
 454                 transform(ctx->buf, ctx->in);
 455                 buf += 64;
 456                 len -= 64;
 457         }
 458
 459         /* Handle any remaining bytes of data. */
 460         memcpy(ctx->in, buf, len);
 461 }
 462
 463 /*
 464  * Final wrapup - pad to 64-byte boundary with the bit pattern
 465  * 1 0* (64-bit count of bits processed, MSB-first)
 466  */
 467 static void
 468 md5_final(md5_t *ctx, unsigned char *digest)
 469 {
 470         int count = ctx->bytes[0] & 0x3f;    /* Number of bytes in ctx->in */
 471         unsigned char *p = (unsigned char *)ctx->in + count;
 472
 473         /* Set the first char of padding to 0x80.  There is always room. */
 474         *p++ = 0x80;
 475
 476         /* Bytes of padding needed to make 56 bytes (-8..55) */
 477         count = 56 - 1 - count;
 478
 479         if (count < 0) {        /* Padding forces an extra block */
 480                 memset(p, 0, count + 8);
 481                 byteSwap(ctx->in, 16);
 482                 transform(ctx->buf, ctx->in);
 483                 p = (unsigned char *)ctx->in;
 484                 count = 56;
 485         }
 486         memset(p, 0, count);
 487         byteSwap(ctx->in, 14);
 488
 489         /* Append length in bits and transform */
 490         ctx->in[14] = ctx->bytes[0] << 3;
 491         ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
 492         transform(ctx->buf, ctx->in);
 493
 494         byteSwap(ctx->buf, 4);
 495         memcpy(digest, ctx->buf, 16);
 496         memset(ctx, 0, sizeof(md5_t));  /* In case it's sensitive */
 497 }