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
17int 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(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(to: __aad, from: 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(to: iv, from: nonce, GMAC_NONCE_LEN);
56 memset(s: iv + GMAC_NONCE_LEN, c: 0, n: 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
69struct 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
89void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm)
90{
91 crypto_free_aead(tfm);
92}
93