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// SPDX-License-Identifier: GPL-2.0-only
/*
* AES-128-CMAC with TLen 16 for IEEE 802.11w BIP
* Copyright 2008, Jouni Malinen <j@w1.fi>
* Copyright (C) 2020 Intel Corporation
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/export.h>
#include <linux/err.h>
#include <crypto/aes.h>
#include <net/mac80211.h>
#include "key.h"
#include "aes_cmac.h"
#define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */
#define CMAC_TLEN_256 16 /* CMAC TLen = 128 bits (16 octets) */
#define AAD_LEN 20
static const u8 zero[CMAC_TLEN_256];
int ieee80211_aes_cmac(struct crypto_shash *tfm, const u8 *aad,
const u8 *data, size_t data_len, u8 *mic)
{
int err;
SHASH_DESC_ON_STACK(desc, tfm);
u8 out[AES_BLOCK_SIZE];
const __le16 *fc;
desc->tfm = tfm;
err = crypto_shash_init(desc);
if (err)
return err;
err = crypto_shash_update(desc, aad, AAD_LEN);
if (err)
return err;
fc = (const __le16 *)aad;
if (ieee80211_is_beacon(*fc)) {
/* mask Timestamp field to zero */
err = crypto_shash_update(desc, zero, 8);
if (err)
return err;
err = crypto_shash_update(desc, data + 8,
data_len - 8 - CMAC_TLEN);
if (err)
return err;
} else {
err = crypto_shash_update(desc, data,
data_len - CMAC_TLEN);
if (err)
return err;
}
err = crypto_shash_finup(desc, zero, CMAC_TLEN, out);
if (err)
return err;
memcpy(mic, out, CMAC_TLEN);
return 0;
}
int ieee80211_aes_cmac_256(struct crypto_shash *tfm, const u8 *aad,
const u8 *data, size_t data_len, u8 *mic)
{
int err;
SHASH_DESC_ON_STACK(desc, tfm);
const __le16 *fc;
desc->tfm = tfm;
err = crypto_shash_init(desc);
if (err)
return err;
err = crypto_shash_update(desc, aad, AAD_LEN);
if (err)
return err;
fc = (const __le16 *)aad;
if (ieee80211_is_beacon(*fc)) {
/* mask Timestamp field to zero */
err = crypto_shash_update(desc, zero, 8);
if (err)
return err;
err = crypto_shash_update(desc, data + 8,
data_len - 8 - CMAC_TLEN_256);
if (err)
return err;
} else {
err = crypto_shash_update(desc, data, data_len - CMAC_TLEN_256);
if (err)
return err;
}
return crypto_shash_finup(desc, zero, CMAC_TLEN_256, mic);
}
struct crypto_shash *ieee80211_aes_cmac_key_setup(const u8 key[],
size_t key_len)
{
struct crypto_shash *tfm;
tfm = crypto_alloc_shash("cmac(aes)", 0, 0);
if (!IS_ERR(tfm)) {
int err = crypto_shash_setkey(tfm, key, key_len);
if (err) {
crypto_free_shash(tfm);
return ERR_PTR(err);
}
}
return tfm;
}
void ieee80211_aes_cmac_key_free(struct crypto_shash *tfm)
{
crypto_free_shash(tfm);
}
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