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/*
* SHA1 hash implementation and interface functions
* Copyright (c) 2003-2005, 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.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/
#include "includes.h"
#include "common.h"
#include "sha1.h"
#include "crypto.h"
/**
* hmac_sha1_vector - HMAC-SHA1 over data vector (RFC 2104)
* @key: Key for HMAC operations
* @key_len: Length of the key in bytes
* @num_elem: Number of elements in the data vector
* @addr: Pointers to the data areas
* @len: Lengths of the data blocks
* @mac: Buffer for the hash (20 bytes)
* Returns: 0 on success, -1 on failure
*/
int hmac_sha1_vector(const u8 *key, size_t key_len, size_t num_elem,
const u8 *addr[], const size_t *len, u8 *mac)
{
unsigned char k_pad[64]; /* padding - key XORd with ipad/opad */
unsigned char tk[20];
const u8 *_addr[6];
size_t _len[6], i;
if (num_elem > 5) {
/*
* Fixed limit on the number of fragments to avoid having to
* allocate memory (which could fail).
*/
return -1;
}
/* if key is longer than 64 bytes reset it to key = SHA1(key) */
if (key_len > 64) {
if (sha1_vector(1, &key, &key_len, tk))
return -1;
key = tk;
key_len = 20;
}
/* the HMAC_SHA1 transform looks like:
*
* SHA1(K XOR opad, SHA1(K XOR ipad, text))
*
* where K is an n byte key
* ipad is the byte 0x36 repeated 64 times
* opad is the byte 0x5c repeated 64 times
* and text is the data being protected */
/* start out by storing key in ipad */
os_memset(k_pad, 0, sizeof(k_pad));
os_memcpy(k_pad, key, key_len);
/* XOR key with ipad values */
for (i = 0; i < 64; i++)
k_pad[i] ^= 0x36;
/* perform inner SHA1 */
_addr[0] = k_pad;
_len[0] = 64;
for (i = 0; i < num_elem; i++) {
_addr[i + 1] = addr[i];
_len[i + 1] = len[i];
}
if (sha1_vector(1 + num_elem, _addr, _len, mac))
return -1;
os_memset(k_pad, 0, sizeof(k_pad));
os_memcpy(k_pad, key, key_len);
/* XOR key with opad values */
for (i = 0; i < 64; i++)
k_pad[i] ^= 0x5c;
/* perform outer SHA1 */
_addr[0] = k_pad;
_len[0] = 64;
_addr[1] = mac;
_len[1] = SHA1_MAC_LEN;
return sha1_vector(2, _addr, _len, mac);
}
/**
* hmac_sha1 - HMAC-SHA1 over data buffer (RFC 2104)
* @key: Key for HMAC operations
* @key_len: Length of the key in bytes
* @data: Pointers to the data area
* @data_len: Length of the data area
* @mac: Buffer for the hash (20 bytes)
* Returns: 0 on success, -1 of failure
*/
int hmac_sha1(const u8 *key, size_t key_len, const u8 *data, size_t data_len,
u8 *mac)
{
return hmac_sha1_vector(key, key_len, 1, &data, &data_len, mac);
}
/**
* sha1_prf - SHA1-based Pseudo-Random Function (PRF) (IEEE 802.11i, 8.5.1.1)
* @key: Key for PRF
* @key_len: Length of the key in bytes
* @label: A unique label for each purpose of the PRF
* @data: Extra data to bind into the key
* @data_len: Length of the data
* @buf: Buffer for the generated pseudo-random key
* @buf_len: Number of bytes of key to generate
* Returns: 0 on success, -1 of failure
*
* This function is used to derive new, cryptographically separate keys from a
* given key (e.g., PMK in IEEE 802.11i).
*/
int sha1_prf(const u8 *key, size_t key_len, const char *label,
const u8 *data, size_t data_len, u8 *buf, size_t buf_len)
{
u8 counter = 0;
size_t pos, plen;
u8 hash[SHA1_MAC_LEN];
size_t label_len = os_strlen(label) + 1;
const unsigned char *addr[3];
size_t len[3];
addr[0] = (u8 *) label;
len[0] = label_len;
addr[1] = data;
len[1] = data_len;
addr[2] = &counter;
len[2] = 1;
pos = 0;
while (pos < buf_len) {
plen = buf_len - pos;
if (plen >= SHA1_MAC_LEN) {
if (hmac_sha1_vector(key, key_len, 3, addr, len,
&buf[pos]))
return -1;
pos += SHA1_MAC_LEN;
} else {
if (hmac_sha1_vector(key, key_len, 3, addr, len,
hash))
return -1;
os_memcpy(&buf[pos], hash, plen);
break;
}
counter++;
}
return 0;
}
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