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Annotation of sys/crypto/michael.c, Revision 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: }