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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - net/mac80211/aes_ccm.c
2 * Copyright 2003-2004, Instant802 Networks, Inc.
3 * Copyright 2005-2006, Devicescape Software, Inc.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
10 #include <linux/kernel.h>
11 #include <linux/types.h>
12 #include <linux/crypto.h>
13 #include <linux/err.h>
15 #include <net/mac80211.h>
19 static void aes_ccm_prepare(struct crypto_cipher
*tfm
, u8
*scratch
, u8
*a
)
22 u8
*b_0
, *aad
, *b
, *s_0
;
24 b_0
= scratch
+ 3 * AES_BLOCK_LEN
;
25 aad
= scratch
+ 4 * AES_BLOCK_LEN
;
27 s_0
= scratch
+ AES_BLOCK_LEN
;
29 crypto_cipher_encrypt_one(tfm
, b
, b_0
);
31 /* Extra Authenticate-only data (always two AES blocks) */
32 for (i
= 0; i
< AES_BLOCK_LEN
; i
++)
34 crypto_cipher_encrypt_one(tfm
, b
, aad
);
38 for (i
= 0; i
< AES_BLOCK_LEN
; i
++)
40 crypto_cipher_encrypt_one(tfm
, a
, aad
);
42 /* Mask out bits from auth-only-b_0 */
45 /* S_0 is used to encrypt T (= MIC) */
48 crypto_cipher_encrypt_one(tfm
, s_0
, b_0
);
52 void ieee80211_aes_ccm_encrypt(struct crypto_cipher
*tfm
, u8
*scratch
,
53 u8
*data
, size_t data_len
,
56 int i
, j
, last_len
, num_blocks
;
57 u8
*pos
, *cpos
, *b
, *s_0
, *e
, *b_0
, *aad
;
60 s_0
= scratch
+ AES_BLOCK_LEN
;
61 e
= scratch
+ 2 * AES_BLOCK_LEN
;
62 b_0
= scratch
+ 3 * AES_BLOCK_LEN
;
63 aad
= scratch
+ 4 * AES_BLOCK_LEN
;
65 num_blocks
= DIV_ROUND_UP(data_len
, AES_BLOCK_LEN
);
66 last_len
= data_len
% AES_BLOCK_LEN
;
67 aes_ccm_prepare(tfm
, scratch
, b
);
69 /* Process payload blocks */
72 for (j
= 1; j
<= num_blocks
; j
++) {
73 int blen
= (j
== num_blocks
&& last_len
) ?
74 last_len
: AES_BLOCK_LEN
;
76 /* Authentication followed by encryption */
77 for (i
= 0; i
< blen
; i
++)
79 crypto_cipher_encrypt_one(tfm
, b
, b
);
81 b_0
[14] = (j
>> 8) & 0xff;
83 crypto_cipher_encrypt_one(tfm
, e
, b_0
);
84 for (i
= 0; i
< blen
; i
++)
85 *cpos
++ = *pos
++ ^ e
[i
];
88 for (i
= 0; i
< CCMP_MIC_LEN
; i
++)
89 mic
[i
] = b
[i
] ^ s_0
[i
];
93 int ieee80211_aes_ccm_decrypt(struct crypto_cipher
*tfm
, u8
*scratch
,
94 u8
*cdata
, size_t data_len
, u8
*mic
, u8
*data
)
96 int i
, j
, last_len
, num_blocks
;
97 u8
*pos
, *cpos
, *b
, *s_0
, *a
, *b_0
, *aad
;
100 s_0
= scratch
+ AES_BLOCK_LEN
;
101 a
= scratch
+ 2 * AES_BLOCK_LEN
;
102 b_0
= scratch
+ 3 * AES_BLOCK_LEN
;
103 aad
= scratch
+ 4 * AES_BLOCK_LEN
;
105 num_blocks
= DIV_ROUND_UP(data_len
, AES_BLOCK_LEN
);
106 last_len
= data_len
% AES_BLOCK_LEN
;
107 aes_ccm_prepare(tfm
, scratch
, a
);
109 /* Process payload blocks */
112 for (j
= 1; j
<= num_blocks
; j
++) {
113 int blen
= (j
== num_blocks
&& last_len
) ?
114 last_len
: AES_BLOCK_LEN
;
116 /* Decryption followed by authentication */
117 b_0
[14] = (j
>> 8) & 0xff;
119 crypto_cipher_encrypt_one(tfm
, b
, b_0
);
120 for (i
= 0; i
< blen
; i
++) {
121 *pos
= *cpos
++ ^ b
[i
];
124 crypto_cipher_encrypt_one(tfm
, a
, a
);
127 for (i
= 0; i
< CCMP_MIC_LEN
; i
++) {
128 if ((mic
[i
] ^ s_0
[i
]) != a
[i
])
136 struct crypto_cipher
*ieee80211_aes_key_setup_encrypt(const u8 key
[])
138 struct crypto_cipher
*tfm
;
140 tfm
= crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC
);
144 crypto_cipher_setkey(tfm
, key
, ALG_CCMP_KEY_LEN
);
150 void ieee80211_aes_key_free(struct crypto_cipher
*tfm
)
153 crypto_free_cipher(tfm
);