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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 <[email protected]>
- * 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];
- void ieee80211_aes_cmac(struct crypto_shash *tfm, const u8 *aad,
- const u8 *data, size_t data_len, u8 *mic)
- {
- SHASH_DESC_ON_STACK(desc, tfm);
- u8 out[AES_BLOCK_SIZE];
- const __le16 *fc;
- desc->tfm = tfm;
- crypto_shash_init(desc);
- crypto_shash_update(desc, aad, AAD_LEN);
- fc = (const __le16 *)aad;
- if (ieee80211_is_beacon(*fc)) {
- /* mask Timestamp field to zero */
- crypto_shash_update(desc, zero, 8);
- crypto_shash_update(desc, data + 8, data_len - 8 - CMAC_TLEN);
- } else {
- crypto_shash_update(desc, data, data_len - CMAC_TLEN);
- }
- crypto_shash_finup(desc, zero, CMAC_TLEN, out);
- memcpy(mic, out, CMAC_TLEN);
- }
- void ieee80211_aes_cmac_256(struct crypto_shash *tfm, const u8 *aad,
- const u8 *data, size_t data_len, u8 *mic)
- {
- SHASH_DESC_ON_STACK(desc, tfm);
- const __le16 *fc;
- desc->tfm = tfm;
- crypto_shash_init(desc);
- crypto_shash_update(desc, aad, AAD_LEN);
- fc = (const __le16 *)aad;
- if (ieee80211_is_beacon(*fc)) {
- /* mask Timestamp field to zero */
- crypto_shash_update(desc, zero, 8);
- crypto_shash_update(desc, data + 8,
- data_len - 8 - CMAC_TLEN_256);
- } else {
- crypto_shash_update(desc, data, data_len - CMAC_TLEN_256);
- }
- 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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