1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * AES-GMAC for IEEE 802.11 BIP-GMAC-128 and BIP-GMAC-256 |
4 | * Copyright 2015, Qualcomm Atheros, Inc. |
5 | */ |
6 | |
7 | #include <linux/kernel.h> |
8 | #include <linux/types.h> |
9 | #include <linux/err.h> |
10 | #include <crypto/aead.h> |
11 | #include <crypto/aes.h> |
12 | |
13 | #include <net/mac80211.h> |
14 | #include "key.h" |
15 | #include "aes_gmac.h" |
16 | |
17 | int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce, |
18 | const u8 *data, size_t data_len, u8 *mic) |
19 | { |
20 | struct scatterlist sg[5]; |
21 | u8 *zero, *__aad, iv[AES_BLOCK_SIZE]; |
22 | struct aead_request *aead_req; |
23 | int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm); |
24 | const __le16 *fc; |
25 | int ret; |
26 | |
27 | if (data_len < GMAC_MIC_LEN) |
28 | return -EINVAL; |
29 | |
30 | aead_req = kzalloc(size: reqsize + GMAC_MIC_LEN + GMAC_AAD_LEN, GFP_ATOMIC); |
31 | if (!aead_req) |
32 | return -ENOMEM; |
33 | |
34 | zero = (u8 *)aead_req + reqsize; |
35 | __aad = zero + GMAC_MIC_LEN; |
36 | memcpy(__aad, aad, GMAC_AAD_LEN); |
37 | |
38 | fc = (const __le16 *)aad; |
39 | if (ieee80211_is_beacon(fc: *fc)) { |
40 | /* mask Timestamp field to zero */ |
41 | sg_init_table(sg, 5); |
42 | sg_set_buf(sg: &sg[0], buf: __aad, GMAC_AAD_LEN); |
43 | sg_set_buf(sg: &sg[1], buf: zero, buflen: 8); |
44 | sg_set_buf(sg: &sg[2], buf: data + 8, buflen: data_len - 8 - GMAC_MIC_LEN); |
45 | sg_set_buf(sg: &sg[3], buf: zero, GMAC_MIC_LEN); |
46 | sg_set_buf(sg: &sg[4], buf: mic, GMAC_MIC_LEN); |
47 | } else { |
48 | sg_init_table(sg, 4); |
49 | sg_set_buf(sg: &sg[0], buf: __aad, GMAC_AAD_LEN); |
50 | sg_set_buf(sg: &sg[1], buf: data, buflen: data_len - GMAC_MIC_LEN); |
51 | sg_set_buf(sg: &sg[2], buf: zero, GMAC_MIC_LEN); |
52 | sg_set_buf(sg: &sg[3], buf: mic, GMAC_MIC_LEN); |
53 | } |
54 | |
55 | memcpy(iv, nonce, GMAC_NONCE_LEN); |
56 | memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN); |
57 | iv[AES_BLOCK_SIZE - 1] = 0x01; |
58 | |
59 | aead_request_set_tfm(req: aead_req, tfm); |
60 | aead_request_set_crypt(req: aead_req, src: sg, dst: sg, cryptlen: 0, iv); |
61 | aead_request_set_ad(req: aead_req, GMAC_AAD_LEN + data_len); |
62 | |
63 | ret = crypto_aead_encrypt(req: aead_req); |
64 | kfree_sensitive(objp: aead_req); |
65 | |
66 | return ret; |
67 | } |
68 | |
69 | struct crypto_aead *ieee80211_aes_gmac_key_setup(const u8 key[], |
70 | size_t key_len) |
71 | { |
72 | struct crypto_aead *tfm; |
73 | int err; |
74 | |
75 | tfm = crypto_alloc_aead(alg_name: "gcm(aes)" , type: 0, CRYPTO_ALG_ASYNC); |
76 | if (IS_ERR(ptr: tfm)) |
77 | return tfm; |
78 | |
79 | err = crypto_aead_setkey(tfm, key, keylen: key_len); |
80 | if (!err) |
81 | err = crypto_aead_setauthsize(tfm, GMAC_MIC_LEN); |
82 | if (!err) |
83 | return tfm; |
84 | |
85 | crypto_free_aead(tfm); |
86 | return ERR_PTR(error: err); |
87 | } |
88 | |
89 | void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm) |
90 | { |
91 | crypto_free_aead(tfm); |
92 | } |
93 | |