149 lines
3.6 KiB
C
149 lines
3.6 KiB
C
/*
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* Driver for KeyStream wireless LAN
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*
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* Copyright (C) 2005-2008 KeyStream Corp.
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* Copyright (C) 2009 Renesas Technology Corp.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/types.h>
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#include <linux/string.h>
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#include "michael_mic.h"
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// Rotation functions on 32 bit values
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#define ROL32(A, n) (((A) << (n)) | (((A) >> (32 - (n))) & ((1UL << (n)) - 1)))
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#define ROR32(A, n) ROL32((A), 32 - (n))
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// Convert from Byte[] to UInt32 in a portable way
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#define getUInt32(A, B) ((uint32_t)(A[B + 0] << 0) \
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+ (A[B + 1] << 8) + (A[B + 2] << 16) + (A[B + 3] << 24))
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// Convert from UInt32 to Byte[] in a portable way
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#define putUInt32(A, B, C) \
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do { \
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A[B + 0] = (uint8_t)(C & 0xff); \
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A[B + 1] = (uint8_t)((C >> 8) & 0xff); \
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A[B + 2] = (uint8_t)((C >> 16) & 0xff); \
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A[B + 3] = (uint8_t)((C >> 24) & 0xff); \
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} while (0)
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// Reset the state to the empty message.
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#define MichaelClear(A) \
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do { \
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A->L = A->K0; \
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A->R = A->K1; \
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A->nBytesInM = 0; \
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} while (0)
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static
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void MichaelInitializeFunction(struct michael_mic_t *Mic, uint8_t *key)
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{
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// Set the key
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Mic->K0 = getUInt32(key, 0);
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Mic->K1 = getUInt32(key, 4);
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//clear();
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MichaelClear(Mic);
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}
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#define MichaelBlockFunction(L, R) \
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do { \
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R ^= ROL32(L, 17); \
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L += R; \
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R ^= ((L & 0xff00ff00) >> 8) | ((L & 0x00ff00ff) << 8); \
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L += R; \
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R ^= ROL32(L, 3); \
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L += R; \
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R ^= ROR32(L, 2); \
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L += R; \
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} while (0)
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static
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void MichaelAppend(struct michael_mic_t *Mic, uint8_t *src, int nBytes)
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{
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int addlen;
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if (Mic->nBytesInM) {
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addlen = 4 - Mic->nBytesInM;
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if (addlen > nBytes)
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addlen = nBytes;
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memcpy(&Mic->M[Mic->nBytesInM], src, addlen);
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Mic->nBytesInM += addlen;
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src += addlen;
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nBytes -= addlen;
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if (Mic->nBytesInM < 4)
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return;
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Mic->L ^= getUInt32(Mic->M, 0);
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MichaelBlockFunction(Mic->L, Mic->R);
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Mic->nBytesInM = 0;
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}
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while (nBytes >= 4) {
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Mic->L ^= getUInt32(src, 0);
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MichaelBlockFunction(Mic->L, Mic->R);
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src += 4;
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nBytes -= 4;
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}
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if (nBytes > 0) {
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Mic->nBytesInM = nBytes;
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memcpy(Mic->M, src, nBytes);
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}
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}
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static
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void MichaelGetMIC(struct michael_mic_t *Mic, uint8_t *dst)
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{
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u8 *data = Mic->M;
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switch (Mic->nBytesInM) {
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case 0:
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Mic->L ^= 0x5a;
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break;
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case 1:
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Mic->L ^= data[0] | 0x5a00;
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break;
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case 2:
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Mic->L ^= data[0] | (data[1] << 8) | 0x5a0000;
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break;
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case 3:
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Mic->L ^= data[0] | (data[1] << 8) | (data[2] << 16) |
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0x5a000000;
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break;
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}
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MichaelBlockFunction(Mic->L, Mic->R);
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MichaelBlockFunction(Mic->L, Mic->R);
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// The appendByte function has already computed the result.
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putUInt32(dst, 0, Mic->L);
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putUInt32(dst, 4, Mic->R);
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// Reset to the empty message.
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MichaelClear(Mic);
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}
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void MichaelMICFunction(struct michael_mic_t *Mic, u8 *Key,
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u8 *Data, int Len, u8 priority,
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u8 *Result)
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{
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u8 pad_data[4] = { priority, 0, 0, 0 };
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// Compute the MIC value
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/*
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* IEEE802.11i page 47
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* Figure 43g TKIP MIC processing format
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* +--+--+--------+--+----+--+--+--+--+--+--+--+--+
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* |6 |6 |1 |3 |M |1 |1 |1 |1 |1 |1 |1 |1 | Octet
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* +--+--+--------+--+----+--+--+--+--+--+--+--+--+
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* |DA|SA|Priority|0 |Data|M0|M1|M2|M3|M4|M5|M6|M7|
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* +--+--+--------+--+----+--+--+--+--+--+--+--+--+
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*/
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MichaelInitializeFunction(Mic, Key);
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MichaelAppend(Mic, (uint8_t *)Data, 12); /* |DA|SA| */
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MichaelAppend(Mic, pad_data, 4); /* |Priority|0|0|0| */
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MichaelAppend(Mic, (uint8_t *)(Data + 12), Len - 12); /* |Data| */
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MichaelGetMIC(Mic, Result);
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}
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