Return to michael.c CVS log

Up to [local] / sys / crypto

Annotation of sys/crypto/michael.c, Revision 1.1.1.1

1.1       nbrk        1: /*     $OpenBSD: michael.c,v 1.1 2006/03/21 18:40:54 reyk Exp $        */
                      2:
                      3: /*
                      4:  * Copyright (c) 2005, 2006 Reyk Floeter <reyk@openbsd.org>
                      5:  *
                      6:  * Permission to use, copy, modify, and distribute this software for any
                      7:  * purpose with or without fee is hereby granted, provided that the above
                      8:  * copyright notice and this permission notice appear in all copies.
                      9:  *
                     10:  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
                     11:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
                     12:  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
                     13:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
                     14:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
                     15:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
                     16:  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
                     17:  */
                     18:
                     19: /*
                     20:  * Implementation of the Michael MIC as defined in IEEE 802.11i for TKIP.
                     21:  * The MIC generates a 64bit digest, which shouldn't be used for any other
                     22:  * applications except TKIP.
                     23:  */
                     24:
                     25: #include <sys/param.h>
                     26: #include <sys/systm.h>
                     27:
                     28: #include <crypto/michael.h>
                     29:
                     30: #define ROL(n, x)      (((x) << (n)) | ((x) >> (32 - (n))))
                     31: #define ROR(n, x)      (((x) >> (n)) | ((x) << (32 - (n))))
                     32: #define VAL32(x)       (*((u_int32_t *)(x)))
                     33: #define XSWAP(x)       (((x) & 0xff00ff00UL) >> 8) | ((((x) & 0x00ff00ffUL) << 8))
                     34:
                     35: #define MICHAEL_BLOCK(l, r) do {                                               \
                     36:        r ^= ROL(17, l);                                                        \
                     37:        l += r;                                                                 \
                     38:        r ^= XSWAP(l);                                                          \
                     39:        l += r;                                                                 \
                     40:        r ^= ROL(3, l);                                                         \
                     41:        l += r;                                                                 \
                     42:        r ^= ROR(2, l);                                                         \
                     43:        l += r;                                                                 \
                     44: } while (0)
                     45:
                     46: void
                     47: michael_init(MICHAEL_CTX *ctx)
                     48: {
                     49:        bzero(ctx, sizeof(MICHAEL_CTX));
                     50: }
                     51:
                     52: void
                     53: michael_update(MICHAEL_CTX *ctx, const u_int8_t *data, u_int len)
                     54: {
                     55:        int i;
                     56:
                     57:        for (i = 0; i < len; i++) {
                     58:                ctx->michael_state |= data[i] << (ctx->michael_count << 3);
                     59:                ctx->michael_count++;
                     60:
                     61:                if (ctx->michael_count >= MICHAEL_RAW_BLOCK_LENGTH) {
                     62:                        ctx->michael_l ^= ctx->michael_state;
                     63:                        MICHAEL_BLOCK(ctx->michael_l, ctx->michael_r);
                     64:                        ctx->michael_state = ctx->michael_count = 0;
                     65:                }
                     66:        }
                     67: }
                     68:
                     69: void
                     70: michael_final(u_int8_t digest[MICHAEL_DIGEST_LENGTH], MICHAEL_CTX *ctx)
                     71: {
                     72:        u_int8_t pad[] = { 0x5a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
                     73:
                     74:        michael_update(ctx, pad, sizeof(pad));
                     75:
                     76:        VAL32(digest) = letoh32(ctx->michael_l);
                     77:        VAL32(digest + MICHAEL_RAW_BLOCK_LENGTH) = letoh32(ctx->michael_r);
                     78: }
                     79:
                     80: void
                     81: michael_key(const u_int8_t *key, MICHAEL_CTX *ctx)
                     82: {
                     83:        ctx->michael_l = ctx->michael_key[0] =
                     84:            htole32(VAL32(key));
                     85:        ctx->michael_r = ctx->michael_key[1] =
                     86:            htole32(VAL32(key + MICHAEL_RAW_BLOCK_LENGTH));
                     87: }