1252190Srpaulo/* 2252190Srpaulo * SHA1-based PRF 3252190Srpaulo * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi> 4252190Srpaulo * 5252190Srpaulo * This software may be distributed under the terms of the BSD license. 6252190Srpaulo * See README for more details. 7252190Srpaulo */ 8252190Srpaulo 9252190Srpaulo#include "includes.h" 10252190Srpaulo 11252190Srpaulo#include "common.h" 12252190Srpaulo#include "sha1.h" 13252190Srpaulo#include "crypto.h" 14252190Srpaulo 15252190Srpaulo 16252190Srpaulo/** 17252190Srpaulo * sha1_prf - SHA1-based Pseudo-Random Function (PRF) (IEEE 802.11i, 8.5.1.1) 18252190Srpaulo * @key: Key for PRF 19252190Srpaulo * @key_len: Length of the key in bytes 20252190Srpaulo * @label: A unique label for each purpose of the PRF 21252190Srpaulo * @data: Extra data to bind into the key 22252190Srpaulo * @data_len: Length of the data 23252190Srpaulo * @buf: Buffer for the generated pseudo-random key 24252190Srpaulo * @buf_len: Number of bytes of key to generate 25252190Srpaulo * Returns: 0 on success, -1 of failure 26252190Srpaulo * 27252190Srpaulo * This function is used to derive new, cryptographically separate keys from a 28252190Srpaulo * given key (e.g., PMK in IEEE 802.11i). 29252190Srpaulo */ 30252190Srpauloint sha1_prf(const u8 *key, size_t key_len, const char *label, 31252190Srpaulo const u8 *data, size_t data_len, u8 *buf, size_t buf_len) 32252190Srpaulo{ 33252190Srpaulo u8 counter = 0; 34252190Srpaulo size_t pos, plen; 35252190Srpaulo u8 hash[SHA1_MAC_LEN]; 36252190Srpaulo size_t label_len = os_strlen(label) + 1; 37252190Srpaulo const unsigned char *addr[3]; 38252190Srpaulo size_t len[3]; 39252190Srpaulo 40252190Srpaulo addr[0] = (u8 *) label; 41252190Srpaulo len[0] = label_len; 42252190Srpaulo addr[1] = data; 43252190Srpaulo len[1] = data_len; 44252190Srpaulo addr[2] = &counter; 45252190Srpaulo len[2] = 1; 46252190Srpaulo 47252190Srpaulo pos = 0; 48252190Srpaulo while (pos < buf_len) { 49252190Srpaulo plen = buf_len - pos; 50252190Srpaulo if (plen >= SHA1_MAC_LEN) { 51252190Srpaulo if (hmac_sha1_vector(key, key_len, 3, addr, len, 52252190Srpaulo &buf[pos])) 53252190Srpaulo return -1; 54252190Srpaulo pos += SHA1_MAC_LEN; 55252190Srpaulo } else { 56252190Srpaulo if (hmac_sha1_vector(key, key_len, 3, addr, len, 57252190Srpaulo hash)) 58252190Srpaulo return -1; 59252190Srpaulo os_memcpy(&buf[pos], hash, plen); 60252190Srpaulo break; 61252190Srpaulo } 62252190Srpaulo counter++; 63252190Srpaulo } 64351611Scy forced_memzero(hash, sizeof(hash)); 65252190Srpaulo 66252190Srpaulo return 0; 67252190Srpaulo} 68