99 lines
2.9 KiB
C
99 lines
2.9 KiB
C
/* $OpenBSD: michael.c,v 1.2 2008/07/21 19:52:45 damien Exp $ */
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/*
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* Copyright (c) 2005, 2006 Reyk Floeter <reyk@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* Implementation of the Michael MIC as defined in IEEE 802.11i for TKIP.
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* The MIC generates a 64bit digest, which shouldn't be used for any other
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* applications except TKIP.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <crypto/michael.h>
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#define ROL(n, x) (((x) << (n)) | ((x) >> (32 - (n))))
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#define ROR(n, x) (((x) >> (n)) | ((x) << (32 - (n))))
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#define XSWAP(x) (((x) & 0xff00ff00UL) >> 8 | ((x) & 0x00ff00ffUL) << 8)
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#if defined(__STRICT_ALIGNMENT) || _BYTE_ORDER != _LITTLE_ENDIAN
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#define GETLE32(x) ((x)[0] | (x)[1] << 8 | (x)[2] << 16 | (x)[3] << 24)
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#define PUTLE32(x, v) ((x)[0] = (u_int8_t)(v), \
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(x)[1] = (u_int8_t)((v) >> 8), \
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(x)[2] = (u_int8_t)((v) >> 16), \
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(x)[3] = (u_int8_t)((v) >> 24))
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#else
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#define GETLE32(x) (*((u_int32_t *)(x)))
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#define PUTLE32(x, v) (*((u_int32_t *)(x)) = (v))
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#endif
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#define MICHAEL_BLOCK(l, r) do { \
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r ^= ROL(17, l); \
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l += r; \
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r ^= XSWAP(l); \
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l += r; \
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r ^= ROL(3, l); \
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l += r; \
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r ^= ROR(2, l); \
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l += r; \
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} while (0)
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void
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michael_init(MICHAEL_CTX *ctx)
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{
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bzero(ctx, sizeof(MICHAEL_CTX));
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}
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void
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michael_update(MICHAEL_CTX *ctx, const u_int8_t *data, u_int len)
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{
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int i;
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for (i = 0; i < len; i++) {
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ctx->michael_state |= data[i] << (ctx->michael_count << 3);
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ctx->michael_count++;
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if (ctx->michael_count >= MICHAEL_RAW_BLOCK_LENGTH) {
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ctx->michael_l ^= ctx->michael_state;
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MICHAEL_BLOCK(ctx->michael_l, ctx->michael_r);
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ctx->michael_state = ctx->michael_count = 0;
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}
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}
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}
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void
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michael_final(u_int8_t digest[MICHAEL_DIGEST_LENGTH], MICHAEL_CTX *ctx)
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{
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static const u_int8_t pad[] =
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{ 0x5a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
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michael_update(ctx, pad, sizeof(pad));
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PUTLE32(digest, ctx->michael_l);
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PUTLE32(digest + MICHAEL_RAW_BLOCK_LENGTH, ctx->michael_r);
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}
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void
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michael_key(const u_int8_t *key, MICHAEL_CTX *ctx)
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{
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ctx->michael_l = ctx->michael_key[0] =
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GETLE32(key);
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ctx->michael_r = ctx->michael_key[1] =
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GETLE32(key + MICHAEL_RAW_BLOCK_LENGTH);
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}
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