1/*
2 * Copyright 2014-2015, Qualcomm Atheros, Inc.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#include <linux/kernel.h>
10#include <linux/types.h>
11#include <linux/crypto.h>
12#include <linux/err.h>
13#include <crypto/aes.h>
14
15#include <net/mac80211.h>
16#include "key.h"
17#include "aes_gcm.h"
18
19void ieee80211_aes_gcm_encrypt(struct crypto_aead *tfm, u8 *j_0, u8 *aad,
20			       u8 *data, size_t data_len, u8 *mic)
21{
22	struct scatterlist assoc, pt, ct[2];
23
24	char aead_req_data[sizeof(struct aead_request) +
25			   crypto_aead_reqsize(tfm)]
26		__aligned(__alignof__(struct aead_request));
27	struct aead_request *aead_req = (void *)aead_req_data;
28
29	memset(aead_req, 0, sizeof(aead_req_data));
30
31	sg_init_one(&pt, data, data_len);
32	sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
33	sg_init_table(ct, 2);
34	sg_set_buf(&ct[0], data, data_len);
35	sg_set_buf(&ct[1], mic, IEEE80211_GCMP_MIC_LEN);
36
37	aead_request_set_tfm(aead_req, tfm);
38	aead_request_set_assoc(aead_req, &assoc, assoc.length);
39	aead_request_set_crypt(aead_req, &pt, ct, data_len, j_0);
40
41	crypto_aead_encrypt(aead_req);
42}
43
44int ieee80211_aes_gcm_decrypt(struct crypto_aead *tfm, u8 *j_0, u8 *aad,
45			      u8 *data, size_t data_len, u8 *mic)
46{
47	struct scatterlist assoc, pt, ct[2];
48	char aead_req_data[sizeof(struct aead_request) +
49			   crypto_aead_reqsize(tfm)]
50		__aligned(__alignof__(struct aead_request));
51	struct aead_request *aead_req = (void *)aead_req_data;
52
53	if (data_len == 0)
54		return -EINVAL;
55
56	memset(aead_req, 0, sizeof(aead_req_data));
57
58	sg_init_one(&pt, data, data_len);
59	sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
60	sg_init_table(ct, 2);
61	sg_set_buf(&ct[0], data, data_len);
62	sg_set_buf(&ct[1], mic, IEEE80211_GCMP_MIC_LEN);
63
64	aead_request_set_tfm(aead_req, tfm);
65	aead_request_set_assoc(aead_req, &assoc, assoc.length);
66	aead_request_set_crypt(aead_req, ct, &pt,
67			       data_len + IEEE80211_GCMP_MIC_LEN, j_0);
68
69	return crypto_aead_decrypt(aead_req);
70}
71
72struct crypto_aead *ieee80211_aes_gcm_key_setup_encrypt(const u8 key[],
73							size_t key_len)
74{
75	struct crypto_aead *tfm;
76	int err;
77
78	tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC);
79	if (IS_ERR(tfm))
80		return tfm;
81
82	err = crypto_aead_setkey(tfm, key, key_len);
83	if (err)
84		goto free_aead;
85	err = crypto_aead_setauthsize(tfm, IEEE80211_GCMP_MIC_LEN);
86	if (err)
87		goto free_aead;
88
89	return tfm;
90
91free_aead:
92	crypto_free_aead(tfm);
93	return ERR_PTR(err);
94}
95
96void ieee80211_aes_gcm_key_free(struct crypto_aead *tfm)
97{
98	crypto_free_aead(tfm);
99}
100