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6f693b5d0b
Instead of using a define and conditional building of sha1.c parts, move the T-PRF implementation into a separate file.
320 lines
8.2 KiB
C
320 lines
8.2 KiB
C
/*
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* SHA1 hash implementation and interface functions
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* Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*
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* See README and COPYING for more details.
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*/
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#include "includes.h"
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#include "common.h"
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#include "sha1.h"
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#include "md5.h"
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#include "crypto.h"
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/**
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* hmac_sha1_vector - HMAC-SHA1 over data vector (RFC 2104)
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* @key: Key for HMAC operations
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* @key_len: Length of the key in bytes
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* @num_elem: Number of elements in the data vector
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* @addr: Pointers to the data areas
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* @len: Lengths of the data blocks
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* @mac: Buffer for the hash (20 bytes)
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*/
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void hmac_sha1_vector(const u8 *key, size_t key_len, size_t num_elem,
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const u8 *addr[], const size_t *len, u8 *mac)
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{
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unsigned char k_pad[64]; /* padding - key XORd with ipad/opad */
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unsigned char tk[20];
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const u8 *_addr[6];
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size_t _len[6], i;
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if (num_elem > 5) {
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/*
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* Fixed limit on the number of fragments to avoid having to
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* allocate memory (which could fail).
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*/
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return;
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}
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/* if key is longer than 64 bytes reset it to key = SHA1(key) */
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if (key_len > 64) {
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sha1_vector(1, &key, &key_len, tk);
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key = tk;
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key_len = 20;
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}
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/* the HMAC_SHA1 transform looks like:
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*
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* SHA1(K XOR opad, SHA1(K XOR ipad, text))
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*
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* where K is an n byte key
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* ipad is the byte 0x36 repeated 64 times
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* opad is the byte 0x5c repeated 64 times
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* and text is the data being protected */
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/* start out by storing key in ipad */
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os_memset(k_pad, 0, sizeof(k_pad));
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os_memcpy(k_pad, key, key_len);
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/* XOR key with ipad values */
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for (i = 0; i < 64; i++)
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k_pad[i] ^= 0x36;
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/* perform inner SHA1 */
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_addr[0] = k_pad;
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_len[0] = 64;
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for (i = 0; i < num_elem; i++) {
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_addr[i + 1] = addr[i];
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_len[i + 1] = len[i];
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}
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sha1_vector(1 + num_elem, _addr, _len, mac);
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os_memset(k_pad, 0, sizeof(k_pad));
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os_memcpy(k_pad, key, key_len);
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/* XOR key with opad values */
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for (i = 0; i < 64; i++)
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k_pad[i] ^= 0x5c;
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/* perform outer SHA1 */
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_addr[0] = k_pad;
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_len[0] = 64;
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_addr[1] = mac;
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_len[1] = SHA1_MAC_LEN;
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sha1_vector(2, _addr, _len, mac);
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}
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/**
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* hmac_sha1 - HMAC-SHA1 over data buffer (RFC 2104)
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* @key: Key for HMAC operations
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* @key_len: Length of the key in bytes
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* @data: Pointers to the data area
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* @data_len: Length of the data area
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* @mac: Buffer for the hash (20 bytes)
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*/
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void hmac_sha1(const u8 *key, size_t key_len, const u8 *data, size_t data_len,
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u8 *mac)
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{
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hmac_sha1_vector(key, key_len, 1, &data, &data_len, mac);
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}
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/**
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* sha1_prf - SHA1-based Pseudo-Random Function (PRF) (IEEE 802.11i, 8.5.1.1)
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* @key: Key for PRF
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* @key_len: Length of the key in bytes
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* @label: A unique label for each purpose of the PRF
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* @data: Extra data to bind into the key
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* @data_len: Length of the data
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* @buf: Buffer for the generated pseudo-random key
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* @buf_len: Number of bytes of key to generate
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*
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* This function is used to derive new, cryptographically separate keys from a
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* given key (e.g., PMK in IEEE 802.11i).
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*/
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void sha1_prf(const u8 *key, size_t key_len, const char *label,
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const u8 *data, size_t data_len, u8 *buf, size_t buf_len)
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{
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u8 counter = 0;
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size_t pos, plen;
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u8 hash[SHA1_MAC_LEN];
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size_t label_len = os_strlen(label) + 1;
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const unsigned char *addr[3];
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size_t len[3];
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addr[0] = (u8 *) label;
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len[0] = label_len;
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addr[1] = data;
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len[1] = data_len;
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addr[2] = &counter;
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len[2] = 1;
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pos = 0;
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while (pos < buf_len) {
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plen = buf_len - pos;
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if (plen >= SHA1_MAC_LEN) {
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hmac_sha1_vector(key, key_len, 3, addr, len,
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&buf[pos]);
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pos += SHA1_MAC_LEN;
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} else {
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hmac_sha1_vector(key, key_len, 3, addr, len,
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hash);
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os_memcpy(&buf[pos], hash, plen);
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break;
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}
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counter++;
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}
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}
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#ifndef CONFIG_NO_TLS_PRF
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/**
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* tls_prf - Pseudo-Random Function for TLS (TLS-PRF, RFC 2246)
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* @secret: Key for PRF
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* @secret_len: Length of the key in bytes
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* @label: A unique label for each purpose of the PRF
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* @seed: Seed value to bind into the key
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* @seed_len: Length of the seed
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* @out: Buffer for the generated pseudo-random key
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* @outlen: Number of bytes of key to generate
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* Returns: 0 on success, -1 on failure.
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*
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* This function is used to derive new, cryptographically separate keys from a
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* given key in TLS. This PRF is defined in RFC 2246, Chapter 5.
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*/
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int tls_prf(const u8 *secret, size_t secret_len, const char *label,
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const u8 *seed, size_t seed_len, u8 *out, size_t outlen)
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{
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size_t L_S1, L_S2, i;
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const u8 *S1, *S2;
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u8 A_MD5[MD5_MAC_LEN], A_SHA1[SHA1_MAC_LEN];
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u8 P_MD5[MD5_MAC_LEN], P_SHA1[SHA1_MAC_LEN];
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int MD5_pos, SHA1_pos;
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const u8 *MD5_addr[3];
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size_t MD5_len[3];
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const unsigned char *SHA1_addr[3];
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size_t SHA1_len[3];
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if (secret_len & 1)
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return -1;
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MD5_addr[0] = A_MD5;
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MD5_len[0] = MD5_MAC_LEN;
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MD5_addr[1] = (unsigned char *) label;
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MD5_len[1] = os_strlen(label);
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MD5_addr[2] = seed;
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MD5_len[2] = seed_len;
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SHA1_addr[0] = A_SHA1;
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SHA1_len[0] = SHA1_MAC_LEN;
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SHA1_addr[1] = (unsigned char *) label;
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SHA1_len[1] = os_strlen(label);
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SHA1_addr[2] = seed;
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SHA1_len[2] = seed_len;
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/* RFC 2246, Chapter 5
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* A(0) = seed, A(i) = HMAC(secret, A(i-1))
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* P_hash = HMAC(secret, A(1) + seed) + HMAC(secret, A(2) + seed) + ..
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* PRF = P_MD5(S1, label + seed) XOR P_SHA-1(S2, label + seed)
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*/
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L_S1 = L_S2 = (secret_len + 1) / 2;
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S1 = secret;
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S2 = secret + L_S1;
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if (secret_len & 1) {
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/* The last byte of S1 will be shared with S2 */
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S2--;
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}
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hmac_md5_vector(S1, L_S1, 2, &MD5_addr[1], &MD5_len[1], A_MD5);
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hmac_sha1_vector(S2, L_S2, 2, &SHA1_addr[1], &SHA1_len[1], A_SHA1);
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MD5_pos = MD5_MAC_LEN;
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SHA1_pos = SHA1_MAC_LEN;
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for (i = 0; i < outlen; i++) {
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if (MD5_pos == MD5_MAC_LEN) {
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hmac_md5_vector(S1, L_S1, 3, MD5_addr, MD5_len, P_MD5);
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MD5_pos = 0;
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hmac_md5(S1, L_S1, A_MD5, MD5_MAC_LEN, A_MD5);
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}
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if (SHA1_pos == SHA1_MAC_LEN) {
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hmac_sha1_vector(S2, L_S2, 3, SHA1_addr, SHA1_len,
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P_SHA1);
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SHA1_pos = 0;
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hmac_sha1(S2, L_S2, A_SHA1, SHA1_MAC_LEN, A_SHA1);
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}
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out[i] = P_MD5[MD5_pos] ^ P_SHA1[SHA1_pos];
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MD5_pos++;
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SHA1_pos++;
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}
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return 0;
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}
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#endif /* CONFIG_NO_TLS_PRF */
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#ifndef CONFIG_NO_PBKDF2
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static void pbkdf2_sha1_f(const char *passphrase, const char *ssid,
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size_t ssid_len, int iterations, unsigned int count,
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u8 *digest)
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{
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unsigned char tmp[SHA1_MAC_LEN], tmp2[SHA1_MAC_LEN];
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int i, j;
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unsigned char count_buf[4];
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const u8 *addr[2];
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size_t len[2];
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size_t passphrase_len = os_strlen(passphrase);
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addr[0] = (u8 *) ssid;
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len[0] = ssid_len;
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addr[1] = count_buf;
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len[1] = 4;
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/* F(P, S, c, i) = U1 xor U2 xor ... Uc
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* U1 = PRF(P, S || i)
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* U2 = PRF(P, U1)
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* Uc = PRF(P, Uc-1)
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*/
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count_buf[0] = (count >> 24) & 0xff;
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count_buf[1] = (count >> 16) & 0xff;
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count_buf[2] = (count >> 8) & 0xff;
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count_buf[3] = count & 0xff;
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hmac_sha1_vector((u8 *) passphrase, passphrase_len, 2, addr, len, tmp);
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os_memcpy(digest, tmp, SHA1_MAC_LEN);
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for (i = 1; i < iterations; i++) {
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hmac_sha1((u8 *) passphrase, passphrase_len, tmp, SHA1_MAC_LEN,
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tmp2);
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os_memcpy(tmp, tmp2, SHA1_MAC_LEN);
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for (j = 0; j < SHA1_MAC_LEN; j++)
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digest[j] ^= tmp2[j];
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}
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}
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/**
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* pbkdf2_sha1 - SHA1-based key derivation function (PBKDF2) for IEEE 802.11i
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* @passphrase: ASCII passphrase
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* @ssid: SSID
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* @ssid_len: SSID length in bytes
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* @iterations: Number of iterations to run
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* @buf: Buffer for the generated key
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* @buflen: Length of the buffer in bytes
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*
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* This function is used to derive PSK for WPA-PSK. For this protocol,
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* iterations is set to 4096 and buflen to 32. This function is described in
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* IEEE Std 802.11-2004, Clause H.4. The main construction is from PKCS#5 v2.0.
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*/
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void pbkdf2_sha1(const char *passphrase, const char *ssid, size_t ssid_len,
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int iterations, u8 *buf, size_t buflen)
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{
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unsigned int count = 0;
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unsigned char *pos = buf;
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size_t left = buflen, plen;
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unsigned char digest[SHA1_MAC_LEN];
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while (left > 0) {
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count++;
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pbkdf2_sha1_f(passphrase, ssid, ssid_len, iterations, count,
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digest);
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plen = left > SHA1_MAC_LEN ? SHA1_MAC_LEN : left;
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os_memcpy(pos, digest, plen);
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pos += plen;
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left -= plen;
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}
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}
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#endif /* CONFIG_NO_PBKDF2 */
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