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
ieee80211_aes_gmac(struct crypto_aead * tfm,const u8 * aad,u8 * nonce,const u8 * data,size_t data_len,u8 * mic)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(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)) {
40 /* mask Timestamp field to zero */
41 sg_init_table(sg, 5);
42 sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN);
43 sg_set_buf(&sg[1], zero, 8);
44 sg_set_buf(&sg[2], data + 8, data_len - 8 - GMAC_MIC_LEN);
45 sg_set_buf(&sg[3], zero, GMAC_MIC_LEN);
46 sg_set_buf(&sg[4], mic, GMAC_MIC_LEN);
47 } else {
48 sg_init_table(sg, 4);
49 sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN);
50 sg_set_buf(&sg[1], data, data_len - GMAC_MIC_LEN);
51 sg_set_buf(&sg[2], zero, GMAC_MIC_LEN);
52 sg_set_buf(&sg[3], 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(aead_req, tfm);
60 aead_request_set_crypt(aead_req, sg, sg, 0, iv);
61 aead_request_set_ad(aead_req, GMAC_AAD_LEN + data_len);
62
63 ret = crypto_aead_encrypt(aead_req);
64 kfree_sensitive(aead_req);
65
66 return ret;
67 }
68
ieee80211_aes_gmac_key_setup(const u8 key[],size_t key_len)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("gcm(aes)", 0, CRYPTO_ALG_ASYNC);
76 if (IS_ERR(tfm))
77 return tfm;
78
79 err = crypto_aead_setkey(tfm, key, 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(err);
87 }
88
ieee80211_aes_gmac_key_free(struct crypto_aead * tfm)89 void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm)
90 {
91 crypto_free_aead(tfm);
92 }
93