1/*
  2 * Copyright 2003-2004, Instant802 Networks, Inc.
  3 * Copyright 2005-2006, Devicescape Software, Inc.
  4 *
  5 * Rewrite: Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 */
 11
 12#include <linux/kernel.h>
 13#include <linux/types.h>
 14#include <linux/err.h>
 15#include <crypto/aead.h>
 16
 17#include <net/mac80211.h>
 18#include "key.h"
 19#include "aes_ccm.h"
 20
 21void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
 22			       u8 *data, size_t data_len, u8 *mic,
 23			       size_t mic_len)
 24{
 25	struct scatterlist sg[3];
 26
 27	char aead_req_data[sizeof(struct aead_request) +
 28			   crypto_aead_reqsize(tfm)]
 29		__aligned(__alignof__(struct aead_request));
 30	struct aead_request *aead_req = (void *) aead_req_data;
 31
 32	memset(aead_req, 0, sizeof(aead_req_data));
 33
 34	sg_init_table(sg, 3);
 35	sg_set_buf(&sg[0], &aad[2], be16_to_cpup((__be16 *)aad));
 36	sg_set_buf(&sg[1], data, data_len);
 37	sg_set_buf(&sg[2], mic, mic_len);
 38
 39	aead_request_set_tfm(aead_req, tfm);
 40	aead_request_set_crypt(aead_req, sg, sg, data_len, b_0);
 41	aead_request_set_ad(aead_req, sg[0].length);
 42
 43	crypto_aead_encrypt(aead_req);
 44}
 45
 46int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
 47			      u8 *data, size_t data_len, u8 *mic,
 48			      size_t mic_len)
 49{
 50	struct scatterlist sg[3];
 51	char aead_req_data[sizeof(struct aead_request) +
 52			   crypto_aead_reqsize(tfm)]
 53		__aligned(__alignof__(struct aead_request));
 54	struct aead_request *aead_req = (void *) aead_req_data;
 55
 56	if (data_len == 0)
 57		return -EINVAL;
 58
 59	memset(aead_req, 0, sizeof(aead_req_data));
 60
 61	sg_init_table(sg, 3);
 62	sg_set_buf(&sg[0], &aad[2], be16_to_cpup((__be16 *)aad));
 63	sg_set_buf(&sg[1], data, data_len);
 64	sg_set_buf(&sg[2], mic, mic_len);
 65
 66	aead_request_set_tfm(aead_req, tfm);
 67	aead_request_set_crypt(aead_req, sg, sg, data_len + mic_len, b_0);
 68	aead_request_set_ad(aead_req, sg[0].length);
 69
 70	return crypto_aead_decrypt(aead_req);
 71}
 72
 73struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[],
 74						    size_t key_len,
 75						    size_t mic_len)
 76{
 77	struct crypto_aead *tfm;
 78	int err;
 79
 80	tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
 81	if (IS_ERR(tfm))
 82		return tfm;
 83
 84	err = crypto_aead_setkey(tfm, key, key_len);
 85	if (err)
 86		goto free_aead;
 87	err = crypto_aead_setauthsize(tfm, mic_len);
 88	if (err)
 89		goto free_aead;
 90
 91	return tfm;
 92
 93free_aead:
 94	crypto_free_aead(tfm);
 95	return ERR_PTR(err);
 96}
 97
 98void ieee80211_aes_key_free(struct crypto_aead *tfm)
 99{
100	crypto_free_aead(tfm);
101}