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/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
* Sun elects to license this software under the BSD license.
* See README for more details.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sys/types.h>
#include <openssl/aes.h>
#include <openssl/hmac.h>
#include <openssl/rc4.h>
#include "wpa_enc.h"
/*
* @kek: key encryption key (KEK)
* @n: length of the wrapped key in 64-bit units; e.g., 2 = 128-bit = 16 bytes
* @plain: plaintext key to be wrapped, n * 64 bit
* @cipher: wrapped key, (n + 1) * 64 bit
*/
void
aes_wrap(uint8_t *kek, int n, uint8_t *plain, uint8_t *cipher)
{
uint8_t *a, *r, b[16];
int i, j;
AES_KEY key;
a = cipher;
r = cipher + 8;
/* 1) Initialize variables. */
(void) memset(a, 0xa6, 8);
(void) memcpy(r, plain, 8 * n);
(void) AES_set_encrypt_key(kek, 128, &key);
/*
* 2) Calculate intermediate values.
* For j = 0 to 5
* For i=1 to n
* B = AES(K, A | R[i])
* A = MSB(64, B) ^ t where t = (n*j)+i
* R[i] = LSB(64, B)
*/
for (j = 0; j <= 5; j++) {
r = cipher + 8;
for (i = 1; i <= n; i++) {
(void) memcpy(b, a, 8);
(void) memcpy(b + 8, r, 8);
AES_encrypt(b, b, &key);
(void) memcpy(a, b, 8);
a[7] ^= n * j + i;
(void) memcpy(r, b + 8, 8);
r += 8;
}
}
/*
* 3) Output the results.
*
* These are already in @cipher due to the location of temporary
* variables.
*/
}
/*
* @kek: key encryption key (KEK)
* @n: length of the wrapped key in 64-bit units; e.g., 2 = 128-bit = 16 bytes
* @cipher: wrapped key to be unwrapped, (n + 1) * 64 bit
* @plain: plaintext key, n * 64 bit
*/
int
aes_unwrap(uint8_t *kek, int n, uint8_t *cipher, uint8_t *plain)
{
uint8_t a[8], *r, b[16];
int i, j;
AES_KEY key;
/* 1) Initialize variables. */
(void) memcpy(a, cipher, 8);
r = plain;
(void) memcpy(r, cipher + 8, 8 * n);
(void) AES_set_decrypt_key(kek, 128, &key);
/*
* 2) Compute intermediate values.
* For j = 5 to 0
* For i = n to 1
* B = AES-1(K, (A ^ t) | R[i]) where t = n*j+i
* A = MSB(64, B)
* R[i] = LSB(64, B)
*/
for (j = 5; j >= 0; j--) {
r = plain + (n - 1) * 8;
for (i = n; i >= 1; i--) {
(void) memcpy(b, a, 8);
b[7] ^= n * j + i;
(void) memcpy(b + 8, r, 8);
AES_decrypt(b, b, &key);
(void) memcpy(a, b, 8);
(void) memcpy(r, b + 8, 8);
r -= 8;
}
}
/*
* 3) Output results.
*
* These are already in @plain due to the location of temporary
* variables. Just verify that the IV matches with the expected value.
*/
for (i = 0; i < 8; i++) {
if (a[i] != 0xa6) {
return (-1);
}
}
return (0);
}
/* RFC 2104 */
void
hmac_sha1(unsigned char *key, unsigned int key_len,
unsigned char *data, unsigned int data_len, unsigned char *mac)
{
unsigned int mac_len = 0;
(void) HMAC(EVP_sha1(), key, key_len, data, data_len, mac, &mac_len);
}
void
hmac_sha1_vector(unsigned char *key, unsigned int key_len, size_t num_elem,
unsigned char *addr[], unsigned int *len, unsigned char *mac)
{
unsigned char *buf, *ptr;
int i, buf_len;
buf_len = 0;
for (i = 0; i < num_elem; i ++)
buf_len += len[i];
buf = malloc(buf_len);
ptr = buf;
for (i = 0; i < num_elem; i ++) {
(void) memcpy(ptr, addr[i], len[i]);
ptr += len[i];
}
hmac_sha1(key, key_len, buf, buf_len, mac);
free(buf);
}
void
sha1_prf(unsigned char *key, unsigned int key_len,
char *label, unsigned char *data, unsigned int data_len,
unsigned char *buf, size_t buf_len)
{
uint8_t zero = 0, counter = 0;
size_t pos, plen;
uint8_t hash[SHA1_MAC_LEN];
size_t label_len = strlen(label);
unsigned char *addr[4];
unsigned int len[4];
addr[0] = (uint8_t *)label;
len[0] = label_len;
addr[1] = &zero;
len[1] = 1;
addr[2] = data;
len[2] = data_len;
addr[3] = &counter;
len[3] = 1;
pos = 0;
while (pos < buf_len) {
plen = buf_len - pos;
if (plen >= SHA1_MAC_LEN) {
hmac_sha1_vector(key, key_len, 4, addr, len, &buf[pos]);
pos += SHA1_MAC_LEN;
} else {
hmac_sha1_vector(key, key_len, 4, addr, len, hash);
(void) memcpy(&buf[pos], hash, plen);
break;
}
counter++;
}
}
void
pbkdf2_sha1(char *passphrase, char *ssid, size_t ssid_len, int iterations,
unsigned char *buf, size_t buflen)
{
(void) PKCS5_PBKDF2_HMAC_SHA1(passphrase, -1, (unsigned char *)ssid,
ssid_len, iterations, buflen, buf);
}
void
rc4_skip(uint8_t *key, size_t keylen, size_t skip,
uint8_t *data, size_t data_len)
{
uint8_t *buf;
size_t buf_len;
buf_len = skip + data_len;
buf = malloc(buf_len);
bzero(buf, buf_len);
bcopy(data, buf + skip, data_len);
rc4(buf, buf_len, key, keylen);
bcopy(buf + skip, data, data_len);
free(buf);
}
void
rc4(uint8_t *buf, size_t len, uint8_t *key, size_t key_len)
{
RC4_KEY k;
RC4_set_key(&k, key_len, key);
RC4(&k, len, buf, buf);
}
void
hmac_md5_vector(uint8_t *key, size_t key_len, size_t num_elem,
uint8_t *addr[], size_t *len, uint8_t *mac)
{
unsigned char *buf, *ptr;
int i, buf_len;
buf_len = 0;
for (i = 0; i < num_elem; i ++)
buf_len += len[i];
buf = malloc(buf_len);
ptr = buf;
for (i = 0; i < num_elem; i ++) {
(void) memcpy(ptr, addr[i], len[i]);
ptr += len[i];
}
hmac_md5(key, key_len, buf, buf_len, mac);
free(buf);
}
/* RFC 2104 */
void
hmac_md5(uint8_t *key, size_t key_len, uint8_t *data,
size_t data_len, uint8_t *mac)
{
unsigned int mac_len = 0;
(void) HMAC(EVP_md5(), key, key_len, data, data_len, mac, &mac_len);
}
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