1 // SPDX-License-Identifier: GPL-2.0-only
3 * AES-128-CMAC with TLen 16 for IEEE 802.11w BIP
4 * Copyright 2008, Jouni Malinen <j@w1.fi>
5 * Copyright (C) 2020 Intel Corporation
8 #include <linux/kernel.h>
9 #include <linux/types.h>
10 #include <linux/crypto.h>
11 #include <linux/export.h>
12 #include <linux/err.h>
13 #include <crypto/aes.h>
15 #include <net/mac80211.h>
19 #define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */
20 #define CMAC_TLEN_256 16 /* CMAC TLen = 128 bits (16 octets) */
23 static const u8 zero[CMAC_TLEN_256];
25 void ieee80211_aes_cmac(struct crypto_shash *tfm, const u8 *aad,
26 const u8 *data, size_t data_len, u8 *mic)
28 SHASH_DESC_ON_STACK(desc, tfm);
29 u8 out[AES_BLOCK_SIZE];
34 crypto_shash_init(desc);
35 crypto_shash_update(desc, aad, AAD_LEN);
36 fc = (const __le16 *)aad;
37 if (ieee80211_is_beacon(*fc)) {
38 /* mask Timestamp field to zero */
39 crypto_shash_update(desc, zero, 8);
40 crypto_shash_update(desc, data + 8, data_len - 8 - CMAC_TLEN);
42 crypto_shash_update(desc, data, data_len - CMAC_TLEN);
44 crypto_shash_finup(desc, zero, CMAC_TLEN, out);
46 memcpy(mic, out, CMAC_TLEN);
49 void ieee80211_aes_cmac_256(struct crypto_shash *tfm, const u8 *aad,
50 const u8 *data, size_t data_len, u8 *mic)
52 SHASH_DESC_ON_STACK(desc, tfm);
57 crypto_shash_init(desc);
58 crypto_shash_update(desc, aad, AAD_LEN);
59 fc = (const __le16 *)aad;
60 if (ieee80211_is_beacon(*fc)) {
61 /* mask Timestamp field to zero */
62 crypto_shash_update(desc, zero, 8);
63 crypto_shash_update(desc, data + 8,
64 data_len - 8 - CMAC_TLEN_256);
66 crypto_shash_update(desc, data, data_len - CMAC_TLEN_256);
68 crypto_shash_finup(desc, zero, CMAC_TLEN_256, mic);
71 struct crypto_shash *ieee80211_aes_cmac_key_setup(const u8 key[],
74 struct crypto_shash *tfm;
76 tfm = crypto_alloc_shash("cmac(aes)", 0, 0);
78 int err = crypto_shash_setkey(tfm, key, key_len);
81 crypto_free_shash(tfm);
89 void ieee80211_aes_cmac_key_free(struct crypto_shash *tfm)
91 crypto_free_shash(tfm);