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>
7 #include <linux/kernel.h>
8 #include <linux/types.h>
9 #include <linux/crypto.h>
10 #include <linux/export.h>
11 #include <linux/err.h>
12 #include <crypto/aes.h>
14 #include <net/mac80211.h>
18 #define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */
19 #define CMAC_TLEN_256 16 /* CMAC TLen = 128 bits (16 octets) */
22 static const u8 zero
[CMAC_TLEN_256
];
24 void ieee80211_aes_cmac(struct crypto_shash
*tfm
, const u8
*aad
,
25 const u8
*data
, size_t data_len
, u8
*mic
)
27 SHASH_DESC_ON_STACK(desc
, tfm
);
28 u8 out
[AES_BLOCK_SIZE
];
33 crypto_shash_init(desc
);
34 crypto_shash_update(desc
, aad
, AAD_LEN
);
35 fc
= (const __le16
*)aad
;
36 if (ieee80211_is_beacon(*fc
)) {
37 /* mask Timestamp field to zero */
38 crypto_shash_update(desc
, zero
, 8);
39 crypto_shash_update(desc
, data
+ 8, data_len
- 8 - CMAC_TLEN
);
41 crypto_shash_update(desc
, data
, data_len
- CMAC_TLEN
);
43 crypto_shash_finup(desc
, zero
, CMAC_TLEN
, out
);
45 memcpy(mic
, out
, CMAC_TLEN
);
48 void ieee80211_aes_cmac_256(struct crypto_shash
*tfm
, const u8
*aad
,
49 const u8
*data
, size_t data_len
, u8
*mic
)
51 SHASH_DESC_ON_STACK(desc
, tfm
);
56 crypto_shash_init(desc
);
57 crypto_shash_update(desc
, aad
, AAD_LEN
);
58 fc
= (const __le16
*)aad
;
59 if (ieee80211_is_beacon(*fc
)) {
60 /* mask Timestamp field to zero */
61 crypto_shash_update(desc
, zero
, 8);
62 crypto_shash_update(desc
, data
+ 8,
63 data_len
- 8 - CMAC_TLEN_256
);
65 crypto_shash_update(desc
, data
, data_len
- CMAC_TLEN_256
);
67 crypto_shash_finup(desc
, zero
, CMAC_TLEN_256
, mic
);
70 struct crypto_shash
*ieee80211_aes_cmac_key_setup(const u8 key
[],
73 struct crypto_shash
*tfm
;
75 tfm
= crypto_alloc_shash("cmac(aes)", 0, 0);
77 crypto_shash_setkey(tfm
, key
, key_len
);
82 void ieee80211_aes_cmac_key_free(struct crypto_shash
*tfm
)
84 crypto_free_shash(tfm
);