[deliverable/linux.git] / net / mac80211 / aes_cmac.c

/*
 * AES-128-CMAC with TLen 16 for IEEE 802.11w BIP
 * Copyright 2008, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/err.h>
#include <crypto/aes.h>

#include <net/mac80211.h>
#include "key.h"
#include "aes_cmac.h"

#define AES_CMAC_KEY_LEN 16
#define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */
#define AAD_LEN 20


static void gf_mulx(u8 *pad)
{
	int i, carry;

	carry = pad[0] & 0x80;
	for (i = 0; i < AES_BLOCK_SIZE - 1; i++)
		pad[i] = (pad[i] << 1) | (pad[i + 1] >> 7);
	pad[AES_BLOCK_SIZE - 1] <<= 1;
	if (carry)
		pad[AES_BLOCK_SIZE - 1] ^= 0x87;
}


static void aes_128_cmac_vector(struct crypto_cipher *tfm, size_t num_elem,
				const u8 *addr[], const size_t *len, u8 *mac)
{
	u8 cbc[AES_BLOCK_SIZE], pad[AES_BLOCK_SIZE];
	const u8 *pos, *end;
	size_t i, e, left, total_len;

	memset(cbc, 0, AES_BLOCK_SIZE);

	total_len = 0;
	for (e = 0; e < num_elem; e++)
		total_len += len[e];
	left = total_len;

	e = 0;
	pos = addr[0];
	end = pos + len[0];

	while (left >= AES_BLOCK_SIZE) {
		for (i = 0; i < AES_BLOCK_SIZE; i++) {
			cbc[i] ^= *pos++;
			if (pos >= end) {
				e++;
				pos = addr[e];
				end = pos + len[e];
			}
		}
		if (left > AES_BLOCK_SIZE)
			crypto_cipher_encrypt_one(tfm, cbc, cbc);
		left -= AES_BLOCK_SIZE;
	}

	memset(pad, 0, AES_BLOCK_SIZE);
	crypto_cipher_encrypt_one(tfm, pad, pad);
	gf_mulx(pad);

	if (left || total_len == 0) {
		for (i = 0; i < left; i++) {
			cbc[i] ^= *pos++;
			if (pos >= end) {
				e++;
				pos = addr[e];
				end = pos + len[e];
			}
		}
		cbc[left] ^= 0x80;
		gf_mulx(pad);
	}

	for (i = 0; i < AES_BLOCK_SIZE; i++)
		pad[i] ^= cbc[i];
	crypto_cipher_encrypt_one(tfm, pad, pad);
	memcpy(mac, pad, CMAC_TLEN);
}


void ieee80211_aes_cmac(struct crypto_cipher *tfm, const u8 *aad,
			const u8 *data, size_t data_len, u8 *mic)
{
	const u8 *addr[3];
	size_t len[3];
	u8 zero[CMAC_TLEN];

	memset(zero, 0, CMAC_TLEN);
	addr[0] = aad;
	len[0] = AAD_LEN;
	addr[1] = data;
	len[1] = data_len - CMAC_TLEN;
	addr[2] = zero;
	len[2] = CMAC_TLEN;

	aes_128_cmac_vector(tfm, 3, addr, len, mic);
}


struct crypto_cipher * ieee80211_aes_cmac_key_setup(const u8 key[])
{
	struct crypto_cipher *tfm;

	tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
	if (!IS_ERR(tfm))
		crypto_cipher_setkey(tfm, key, AES_CMAC_KEY_LEN);

	return tfm;
}


void ieee80211_aes_cmac_key_free(struct crypto_cipher *tfm)
{
	crypto_free_cipher(tfm);
}

void ieee80211_aes_cmac_calculate_k1_k2(struct ieee80211_key_conf *keyconf,
					u8 *k1, u8 *k2)
{
	u8 l[AES_BLOCK_SIZE] = {};
	struct ieee80211_key *key =
		container_of(keyconf, struct ieee80211_key, conf);

	crypto_cipher_encrypt_one(key->u.aes_cmac.tfm, l, l);

	memcpy(k1, l, AES_BLOCK_SIZE);
	gf_mulx(k1);

	memcpy(k2, k1, AES_BLOCK_SIZE);
	gf_mulx(k2);
}
EXPORT_SYMBOL(ieee80211_aes_cmac_calculate_k1_k2);
Commit	Line	Data
765cb46a JM	1	/*
	2	* AES-128-CMAC with TLen 16 for IEEE 802.11w BIP
	3	* Copyright 2008, Jouni Malinen <j@w1.fi>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License version 2 as
	7	* published by the Free Software Foundation.
	8	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/types.h>
	12	#include <linux/crypto.h>
	13	#include <linux/err.h>
0cd20a27	14	#include <crypto/aes.h>
765cb46a JM	15
	16	#include <net/mac80211.h>
	17	#include "key.h"
	18	#include "aes_cmac.h"
	19
765cb46a JM	20	#define AES_CMAC_KEY_LEN 16
	21	#define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */
	22	#define AAD_LEN 20
	23
	24
	25	static void gf_mulx(u8 *pad)
	26	{
	27	int i, carry;
	28
	29	carry = pad[0] & 0x80;
	30	for (i = 0; i < AES_BLOCK_SIZE - 1; i++)
	31	pad[i] = (pad[i] << 1) \| (pad[i + 1] >> 7);
	32	pad[AES_BLOCK_SIZE - 1] <<= 1;
	33	if (carry)
	34	pad[AES_BLOCK_SIZE - 1] ^= 0x87;
	35	}
	36
	37
75396ae6	38	static void aes_128_cmac_vector(struct crypto_cipher *tfm, size_t num_elem,
765cb46a JM	39	const u8 addr[], const size_t len, u8 *mac)
765cb46a JM	40	{
d348f69f	41	u8 cbc[AES_BLOCK_SIZE], pad[AES_BLOCK_SIZE];
765cb46a JM	42	const u8 pos, end;
	43	size_t i, e, left, total_len;
	44
765cb46a JM	45	memset(cbc, 0, AES_BLOCK_SIZE);
	46
	47	total_len = 0;
	48	for (e = 0; e < num_elem; e++)
	49	total_len += len[e];
	50	left = total_len;
	51
	52	e = 0;
	53	pos = addr[0];
	54	end = pos + len[0];
	55
	56	while (left >= AES_BLOCK_SIZE) {
	57	for (i = 0; i < AES_BLOCK_SIZE; i++) {
	58	cbc[i] ^= *pos++;
	59	if (pos >= end) {
	60	e++;
	61	pos = addr[e];
	62	end = pos + len[e];
	63	}
	64	}
	65	if (left > AES_BLOCK_SIZE)
	66	crypto_cipher_encrypt_one(tfm, cbc, cbc);
	67	left -= AES_BLOCK_SIZE;
	68	}
	69
	70	memset(pad, 0, AES_BLOCK_SIZE);
	71	crypto_cipher_encrypt_one(tfm, pad, pad);
	72	gf_mulx(pad);
	73
	74	if (left \|\| total_len == 0) {
	75	for (i = 0; i < left; i++) {
	76	cbc[i] ^= *pos++;
	77	if (pos >= end) {
	78	e++;
	79	pos = addr[e];
	80	end = pos + len[e];
	81	}
	82	}
	83	cbc[left] ^= 0x80;
	84	gf_mulx(pad);
	85	}
	86
	87	for (i = 0; i < AES_BLOCK_SIZE; i++)
	88	pad[i] ^= cbc[i];
	89	crypto_cipher_encrypt_one(tfm, pad, pad);
	90	memcpy(mac, pad, CMAC_TLEN);
	91	}
	92
	93
75396ae6	94	void ieee80211_aes_cmac(struct crypto_cipher tfm, const u8 aad,
765cb46a JM	95	const u8 data, size_t data_len, u8 mic)
	96	{
	97	const u8 *addr[3];
	98	size_t len[3];
	99	u8 zero[CMAC_TLEN];
	100
	101	memset(zero, 0, CMAC_TLEN);
	102	addr[0] = aad;
	103	len[0] = AAD_LEN;
	104	addr[1] = data;
	105	len[1] = data_len - CMAC_TLEN;
	106	addr[2] = zero;
	107	len[2] = CMAC_TLEN;
	108
75396ae6	109	aes_128_cmac_vector(tfm, 3, addr, len, mic);
765cb46a JM	110	}
	111
	112
	113	struct crypto_cipher * ieee80211_aes_cmac_key_setup(const u8 key[])
	114	{
	115	struct crypto_cipher *tfm;
	116
	117	tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
1ac62ba7 BH	118	if (!IS_ERR(tfm))
1ac62ba7 BH	119	crypto_cipher_setkey(tfm, key, AES_CMAC_KEY_LEN);
765cb46a JM	120
	121	return tfm;
	122	}
	123
	124
	125	void ieee80211_aes_cmac_key_free(struct crypto_cipher *tfm)
	126	{
ffa56e54	127	crypto_free_cipher(tfm);
765cb46a	128	}
5d0d04e4 AK	129
	130	void ieee80211_aes_cmac_calculate_k1_k2(struct ieee80211_key_conf *keyconf,
	131	u8 k1, u8 k2)
	132	{
	133	u8 l[AES_BLOCK_SIZE] = {};
	134	struct ieee80211_key *key =
	135	container_of(keyconf, struct ieee80211_key, conf);
	136
	137	crypto_cipher_encrypt_one(key->u.aes_cmac.tfm, l, l);
	138
	139	memcpy(k1, l, AES_BLOCK_SIZE);
	140	gf_mulx(k1);
	141
	142	memcpy(k2, k1, AES_BLOCK_SIZE);
	143	gf_mulx(k2);
	144	}
	145	EXPORT_SYMBOL(ieee80211_aes_cmac_calculate_k1_k2);