380 lines
9.8 KiB
C
380 lines
9.8 KiB
C
/*
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* SHA-256 hash implementation and interface functions
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* Copyright (c) 2003-2006, 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 "sha256.h"
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#include "crypto.h"
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/**
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* hmac_sha256_vector - HMAC-SHA256 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 (32 bytes)
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*/
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void hmac_sha256_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[32];
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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 = SHA256(key) */
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if (key_len > 64) {
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sha256_vector(1, &key, &key_len, tk);
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key = tk;
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key_len = 32;
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}
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/* the HMAC_SHA256 transform looks like:
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*
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* SHA256(K XOR opad, SHA256(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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memset(k_pad, 0, sizeof(k_pad));
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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 SHA256 */
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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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sha256_vector(1 + num_elem, _addr, _len, mac);
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memset(k_pad, 0, sizeof(k_pad));
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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 SHA256 */
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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] = SHA256_MAC_LEN;
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sha256_vector(2, _addr, _len, mac);
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}
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/**
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* hmac_sha256 - HMAC-SHA256 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_sha256(const u8 *key, size_t key_len, const u8 *data,
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size_t data_len, u8 *mac)
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{
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hmac_sha256_vector(key, key_len, 1, &data, &data_len, mac);
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}
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/**
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* sha256_prf - SHA256-based Pseudo-Random Function (IEEE 802.11r, 8.5A.3)
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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.
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*/
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void sha256_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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u16 counter = 0;
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size_t pos, plen;
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u8 hash[SHA256_MAC_LEN];
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const u8 *addr[3];
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size_t len[3];
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u8 counter_le[2];
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addr[0] = counter_le;
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len[0] = 2;
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addr[1] = (u8 *) label;
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len[1] = strlen(label) + 1;
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addr[2] = data;
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len[2] = data_len;
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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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WPA_PUT_LE16(counter_le, counter);
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if (plen >= SHA256_MAC_LEN) {
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hmac_sha256_vector(key, key_len, 3, addr, len,
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&buf[pos]);
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pos += SHA256_MAC_LEN;
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} else {
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hmac_sha256_vector(key, key_len, 3, addr, len, hash);
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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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#ifdef INTERNAL_SHA256
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struct sha256_state {
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u64 length;
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u32 state[8], curlen;
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u8 buf[64];
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};
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static void sha256_init(struct sha256_state *md);
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static int sha256_process(struct sha256_state *md, const unsigned char *in,
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unsigned long inlen);
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static int sha256_done(struct sha256_state *md, unsigned char *out);
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/**
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* sha256_vector - SHA256 hash for data vector
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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
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*/
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void sha256_vector(size_t num_elem, const u8 *addr[], const size_t *len,
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u8 *mac)
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{
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struct sha256_state ctx;
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size_t i;
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sha256_init(&ctx);
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for (i = 0; i < num_elem; i++)
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sha256_process(&ctx, addr[i], len[i]);
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sha256_done(&ctx, mac);
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}
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/* ===== start - public domain SHA256 implementation ===== */
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/* This is based on SHA256 implementation in LibTomCrypt that was released into
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* public domain by Tom St Denis. */
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/* the K array */
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static const unsigned long K[64] = {
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0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL, 0x3956c25bUL,
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0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL, 0xd807aa98UL, 0x12835b01UL,
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0x243185beUL, 0x550c7dc3UL, 0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL,
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0xc19bf174UL, 0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
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0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL, 0x983e5152UL,
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0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL, 0xc6e00bf3UL, 0xd5a79147UL,
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0x06ca6351UL, 0x14292967UL, 0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL,
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0x53380d13UL, 0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
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0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL, 0xd192e819UL,
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0xd6990624UL, 0xf40e3585UL, 0x106aa070UL, 0x19a4c116UL, 0x1e376c08UL,
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0x2748774cUL, 0x34b0bcb5UL, 0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL,
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0x682e6ff3UL, 0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
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0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL
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};
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/* Various logical functions */
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#define RORc(x, y) \
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( ((((unsigned long) (x) & 0xFFFFFFFFUL) >> (unsigned long) ((y) & 31)) | \
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((unsigned long) (x) << (unsigned long) (32 - ((y) & 31)))) & 0xFFFFFFFFUL)
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#define Ch(x,y,z) (z ^ (x & (y ^ z)))
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#define Maj(x,y,z) (((x | y) & z) | (x & y))
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#define S(x, n) RORc((x), (n))
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#define R(x, n) (((x)&0xFFFFFFFFUL)>>(n))
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#define Sigma0(x) (S(x, 2) ^ S(x, 13) ^ S(x, 22))
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#define Sigma1(x) (S(x, 6) ^ S(x, 11) ^ S(x, 25))
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#define Gamma0(x) (S(x, 7) ^ S(x, 18) ^ R(x, 3))
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#define Gamma1(x) (S(x, 17) ^ S(x, 19) ^ R(x, 10))
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#ifndef MIN
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#define MIN(x, y) (((x) < (y)) ? (x) : (y))
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#endif
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/* compress 512-bits */
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static int sha256_compress(struct sha256_state *md, unsigned char *buf)
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{
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u32 S[8], W[64], t0, t1;
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u32 t;
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int i;
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/* copy state into S */
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for (i = 0; i < 8; i++) {
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S[i] = md->state[i];
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}
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/* copy the state into 512-bits into W[0..15] */
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for (i = 0; i < 16; i++)
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W[i] = WPA_GET_BE32(buf + (4 * i));
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/* fill W[16..63] */
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for (i = 16; i < 64; i++) {
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W[i] = Gamma1(W[i - 2]) + W[i - 7] + Gamma0(W[i - 15]) +
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W[i - 16];
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}
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/* Compress */
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#define RND(a,b,c,d,e,f,g,h,i) \
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t0 = h + Sigma1(e) + Ch(e, f, g) + K[i] + W[i]; \
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t1 = Sigma0(a) + Maj(a, b, c); \
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d += t0; \
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h = t0 + t1;
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for (i = 0; i < 64; ++i) {
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RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], i);
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t = S[7]; S[7] = S[6]; S[6] = S[5]; S[5] = S[4];
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S[4] = S[3]; S[3] = S[2]; S[2] = S[1]; S[1] = S[0]; S[0] = t;
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}
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/* feedback */
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for (i = 0; i < 8; i++) {
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md->state[i] = md->state[i] + S[i];
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}
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return 0;
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}
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/* Initialize the hash state */
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static void sha256_init(struct sha256_state *md)
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{
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md->curlen = 0;
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md->length = 0;
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md->state[0] = 0x6A09E667UL;
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md->state[1] = 0xBB67AE85UL;
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md->state[2] = 0x3C6EF372UL;
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md->state[3] = 0xA54FF53AUL;
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md->state[4] = 0x510E527FUL;
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md->state[5] = 0x9B05688CUL;
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md->state[6] = 0x1F83D9ABUL;
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md->state[7] = 0x5BE0CD19UL;
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}
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/**
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Process a block of memory though the hash
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@param md The hash state
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@param in The data to hash
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@param inlen The length of the data (octets)
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@return CRYPT_OK if successful
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*/
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static int sha256_process(struct sha256_state *md, const unsigned char *in,
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unsigned long inlen)
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{
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unsigned long n;
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#define block_size 64
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if (md->curlen > sizeof(md->buf))
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return -1;
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while (inlen > 0) {
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if (md->curlen == 0 && inlen >= block_size) {
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if (sha256_compress(md, (unsigned char *) in) < 0)
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return -1;
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md->length += block_size * 8;
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in += block_size;
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inlen -= block_size;
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} else {
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n = MIN(inlen, (block_size - md->curlen));
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memcpy(md->buf + md->curlen, in, n);
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md->curlen += n;
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in += n;
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inlen -= n;
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if (md->curlen == block_size) {
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if (sha256_compress(md, md->buf) < 0)
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return -1;
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md->length += 8 * block_size;
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md->curlen = 0;
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}
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}
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}
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return 0;
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}
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/**
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Terminate the hash to get the digest
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@param md The hash state
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@param out [out] The destination of the hash (32 bytes)
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@return CRYPT_OK if successful
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*/
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static int sha256_done(struct sha256_state *md, unsigned char *out)
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{
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int i;
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if (md->curlen >= sizeof(md->buf))
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return -1;
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/* increase the length of the message */
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md->length += md->curlen * 8;
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/* append the '1' bit */
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md->buf[md->curlen++] = (unsigned char) 0x80;
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/* if the length is currently above 56 bytes we append zeros
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* then compress. Then we can fall back to padding zeros and length
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* encoding like normal.
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*/
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if (md->curlen > 56) {
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while (md->curlen < 64) {
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md->buf[md->curlen++] = (unsigned char) 0;
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}
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sha256_compress(md, md->buf);
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md->curlen = 0;
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}
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/* pad upto 56 bytes of zeroes */
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while (md->curlen < 56) {
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md->buf[md->curlen++] = (unsigned char) 0;
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}
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/* store length */
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WPA_PUT_BE64(md->buf + 56, md->length);
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sha256_compress(md, md->buf);
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/* copy output */
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for (i = 0; i < 8; i++)
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WPA_PUT_BE32(out + (4 * i), md->state[i]);
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return 0;
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}
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/* ===== end - public domain SHA256 implementation ===== */
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#endif /* INTERNAL_SHA256 */
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