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8ade538b JM |
1 | /* |
2 | * AES-GMAC for IEEE 802.11 BIP-GMAC-128 and BIP-GMAC-256 | |
3 | * Copyright 2015, Qualcomm Atheros, Inc. | |
4 | * | |
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. | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/types.h> | |
12 | #include <linux/crypto.h> | |
13 | #include <linux/err.h> | |
14 | #include <crypto/aes.h> | |
15 | ||
16 | #include <net/mac80211.h> | |
17 | #include "key.h" | |
18 | #include "aes_gmac.h" | |
19 | ||
20 | #define GMAC_MIC_LEN 16 | |
21 | #define GMAC_NONCE_LEN 12 | |
22 | #define AAD_LEN 20 | |
23 | ||
24 | int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce, | |
25 | const u8 *data, size_t data_len, u8 *mic) | |
26 | { | |
27 | struct scatterlist sg[3], ct[1]; | |
28 | char aead_req_data[sizeof(struct aead_request) + | |
29 | crypto_aead_reqsize(tfm)] | |
30 | __aligned(__alignof__(struct aead_request)); | |
31 | struct aead_request *aead_req = (void *)aead_req_data; | |
32 | u8 zero[GMAC_MIC_LEN], iv[AES_BLOCK_SIZE]; | |
33 | ||
34 | if (data_len < GMAC_MIC_LEN) | |
35 | return -EINVAL; | |
36 | ||
37 | memset(aead_req, 0, sizeof(aead_req_data)); | |
38 | ||
39 | memset(zero, 0, GMAC_MIC_LEN); | |
40 | sg_init_table(sg, 3); | |
41 | sg_set_buf(&sg[0], aad, AAD_LEN); | |
42 | sg_set_buf(&sg[1], data, data_len - GMAC_MIC_LEN); | |
43 | sg_set_buf(&sg[2], zero, GMAC_MIC_LEN); | |
44 | ||
45 | memcpy(iv, nonce, GMAC_NONCE_LEN); | |
46 | memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN); | |
47 | iv[AES_BLOCK_SIZE - 1] = 0x01; | |
48 | ||
49 | sg_init_table(ct, 1); | |
50 | sg_set_buf(&ct[0], mic, GMAC_MIC_LEN); | |
51 | ||
52 | aead_request_set_tfm(aead_req, tfm); | |
53 | aead_request_set_assoc(aead_req, sg, AAD_LEN + data_len); | |
54 | aead_request_set_crypt(aead_req, NULL, ct, 0, iv); | |
55 | ||
56 | crypto_aead_encrypt(aead_req); | |
57 | ||
58 | return 0; | |
59 | } | |
60 | ||
61 | struct crypto_aead *ieee80211_aes_gmac_key_setup(const u8 key[], | |
62 | size_t key_len) | |
63 | { | |
64 | struct crypto_aead *tfm; | |
65 | int err; | |
66 | ||
67 | tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC); | |
68 | if (IS_ERR(tfm)) | |
69 | return tfm; | |
70 | ||
71 | err = crypto_aead_setkey(tfm, key, key_len); | |
72 | if (!err) | |
73 | return tfm; | |
74 | if (!err) | |
75 | err = crypto_aead_setauthsize(tfm, GMAC_MIC_LEN); | |
76 | ||
77 | crypto_free_aead(tfm); | |
78 | return ERR_PTR(err); | |
79 | } | |
80 | ||
81 | void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm) | |
82 | { | |
83 | crypto_free_aead(tfm); | |
84 | } |