26717828b7
Instead of open coding the CMAC algorithm in the mac80211 driver using byte wide xors and calls into the crypto layer for each block of data, instantiate a cmac(aes) synchronous hash and pass all the data into it directly. This does not only simplify the code, it also allows the use of more efficient and more secure implementations, especially on platforms where SIMD ciphers have a considerable setup cost. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
72 lines
1.7 KiB
C
72 lines
1.7 KiB
C
/*
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* AES-128-CMAC with TLen 16 for IEEE 802.11w BIP
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* Copyright 2008, Jouni Malinen <j@w1.fi>
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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/kernel.h>
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#include <linux/types.h>
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#include <linux/crypto.h>
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#include <linux/export.h>
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#include <linux/err.h>
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#include <crypto/aes.h>
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#include <net/mac80211.h>
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#include "key.h"
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#include "aes_cmac.h"
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#define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */
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#define CMAC_TLEN_256 16 /* CMAC TLen = 128 bits (16 octets) */
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#define AAD_LEN 20
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static const u8 zero[CMAC_TLEN_256];
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void ieee80211_aes_cmac(struct crypto_shash *tfm, const u8 *aad,
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const u8 *data, size_t data_len, u8 *mic)
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{
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SHASH_DESC_ON_STACK(desc, tfm);
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u8 out[AES_BLOCK_SIZE];
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desc->tfm = tfm;
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crypto_shash_init(desc);
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crypto_shash_update(desc, aad, AAD_LEN);
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crypto_shash_update(desc, data, data_len - CMAC_TLEN);
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crypto_shash_finup(desc, zero, CMAC_TLEN, out);
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memcpy(mic, out, CMAC_TLEN);
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}
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void ieee80211_aes_cmac_256(struct crypto_shash *tfm, const u8 *aad,
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const u8 *data, size_t data_len, u8 *mic)
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{
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SHASH_DESC_ON_STACK(desc, tfm);
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desc->tfm = tfm;
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crypto_shash_init(desc);
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crypto_shash_update(desc, aad, AAD_LEN);
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crypto_shash_update(desc, data, data_len - CMAC_TLEN_256);
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crypto_shash_finup(desc, zero, CMAC_TLEN_256, mic);
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}
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struct crypto_shash *ieee80211_aes_cmac_key_setup(const u8 key[],
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size_t key_len)
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{
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struct crypto_shash *tfm;
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tfm = crypto_alloc_shash("cmac(aes)", 0, 0);
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if (!IS_ERR(tfm))
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crypto_shash_setkey(tfm, key, key_len);
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return tfm;
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}
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void ieee80211_aes_cmac_key_free(struct crypto_shash *tfm)
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{
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crypto_free_shash(tfm);
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}
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