/*
* SHA-256 hash implementation and interface functions
* Copyright (c) 2003-2006, 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 "sha256.h"
#include "crypto.h"
/**
* hmac_sha256_vector - HMAC-SHA256 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 (32 bytes)
*/
void hmac_sha256_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[32];
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;
}
/* if key is longer than 64 bytes reset it to key = SHA256(key) */
if (key_len > 64) {
sha256_vector(1, &key, &key_len, tk);
key = tk;
key_len = 32;
}
/* the HMAC_SHA256 transform looks like:
*
* SHA256(K XOR opad, SHA256(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 */
memset(k_pad, 0, sizeof(k_pad));
memcpy(k_pad, key, key_len);
/* XOR key with ipad values */
for (i = 0; i < 64; i++)
k_pad[i] ^= 0x36;
/* perform inner SHA256 */
_addr[0] = k_pad;
_len[0] = 64;
for (i = 0; i < num_elem; i++) {
_addr[i + 1] = addr[i];
_len[i + 1] = len[i];
}
sha256_vector(1 + num_elem, _addr, _len, mac);
memset(k_pad, 0, sizeof(k_pad));
memcpy(k_pad, key, key_len);
/* XOR key with opad values */
for (i = 0; i < 64; i++)
k_pad[i] ^= 0x5c;
/* perform outer SHA256 */
_addr[0] = k_pad;
_len[0] = 64;
_addr[1] = mac;
_len[1] = SHA256_MAC_LEN;
sha256_vector(2, _addr, _len, mac);
}
/**
* hmac_sha256 - HMAC-SHA256 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)
*/
void hmac_sha256(const u8 *key, size_t key_len, const u8 *data,
size_t data_len, u8 *mac)
{
hmac_sha256_vector(key, key_len, 1, &data, &data_len, mac);
}
/**
* sha256_prf - SHA256-based Pseudo-Random Function (IEEE 802.11r, 8.5A.3)
* @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
*
* This function is used to derive new, cryptographically separate keys from a
* given key.
*/
void sha256_prf(const u8 *key, size_t key_len, const char *label,
const u8 *data, size_t data_len, u8 *buf, size_t buf_len)
{
u16 counter = 0;
size_t pos, plen;
u8 hash[SHA256_MAC_LEN];
const u8 *addr[3];
size_t len[3];
u8 counter_le[2];
addr[0] = counter_le;
len[0] = 2;
addr[1] = (u8 *) label;
len[1] = strlen(label) + 1;
addr[2] = data;
len[2] = data_len;
pos = 0;
while (pos < buf_len) {
plen = buf_len - pos;
WPA_PUT_LE16(counter_le, counter);
if (plen >= SHA256_MAC_LEN) {
hmac_sha256_vector(key, key_len, 3, addr, len,
&buf[pos]);
pos += SHA256_MAC_LEN;
} else {
hmac_sha256_vector(key, key_len, 3, addr, len, hash);
memcpy(&buf[pos], hash, plen);
break;
}
counter++;
}
}
#ifdef INTERNAL_SHA256
struct sha256_state {
u64 length;
u32 state[8], curlen;
u8 buf[64];
};
static void sha256_init(struct sha256_state *md);
static int sha256_process(struct sha256_state *md, const unsigned char *in,
unsigned long inlen);
static int sha256_done(struct sha256_state *md, unsigned char *out);
/**
* sha256_vector - SHA256 hash for data vector
* @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
*/
void sha256_vector(size_t num_elem, const u8 *addr[], const size_t *len,
u8 *mac)
{
struct sha256_state ctx;
size_t i;
sha256_init(&ctx);
for (i = 0; i < num_elem; i++)
sha256_process(&ctx, addr[i], len[i]);
sha256_done(&ctx, mac);
}
/* ===== start - public domain SHA256 implementation ===== */
/* This is based on SHA256 implementation in LibTomCrypt that was released into
* public domain by Tom St Denis. */
/* the K array */
static const unsigned long K[64] = {
0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL, 0x3956c25bUL,
0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL, 0xd807aa98UL, 0x12835b01UL,
0x243185beUL, 0x550c7dc3UL, 0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL,
0xc19bf174UL, 0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL, 0x983e5152UL,
0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL, 0xc6e00bf3UL, 0xd5a79147UL,
0x06ca6351UL, 0x14292967UL, 0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL,
0x53380d13UL, 0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL, 0xd192e819UL,
0xd6990624UL, 0xf40e3585UL, 0x106aa070UL, 0x19a4c116UL, 0x1e376c08UL,
0x2748774cUL, 0x34b0bcb5UL, 0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL,
0x682e6ff3UL, 0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL
};
/* Various logical functions */
#define RORc(x, y) \
( ((((unsigned long) (x) & 0xFFFFFFFFUL) >> (unsigned long) ((y) & 31)) | \
((unsigned long) (x) << (unsigned long) (32 - ((y) & 31)))) & 0xFFFFFFFFUL)
#define Ch(x,y,z) (z ^ (x & (y ^ z)))
#define Maj(x,y,z) (((x | y) & z) | (x & y))
#define S(x, n) RORc((x), (n))
#define R(x, n) (((x)&0xFFFFFFFFUL)>>(n))
#define Sigma0(x) (S(x, 2) ^ S(x, 13) ^ S(x, 22))
#define Sigma1(x) (S(x, 6) ^ S(x, 11) ^ S(x, 25))
#define Gamma0(x) (S(x, 7) ^ S(x, 18) ^ R(x, 3))
#define Gamma1(x) (S(x, 17) ^ S(x, 19) ^ R(x, 10))
#ifndef MIN
#define MIN(x, y) (((x) < (y)) ? (x) : (y))
#endif
/* compress 512-bits */
static int sha256_compress(struct sha256_state *md, unsigned char *buf)
{
u32 S[8], W[64], t0, t1;
u32 t;
int i;
/* copy state into S */
for (i = 0; i < 8; i++) {
S[i] = md->state[i];
}
/* copy the state into 512-bits into W[0..15] */
for (i = 0; i < 16; i++)
W[i] = WPA_GET_BE32(buf + (4 * i));
/* fill W[16..63] */
for (i = 16; i < 64; i++) {
W[i] = Gamma1(W[i - 2]) + W[i - 7] + Gamma0(W[i - 15]) +
W[i - 16];
}
/* Compress */
#define RND(a,b,c,d,e,f,g,h,i) \
t0 = h + Sigma1(e) + Ch(e, f, g) + K[i] + W[i]; \
t1 = Sigma0(a) + Maj(a, b, c); \
d += t0; \
h = t0 + t1;
for (i = 0; i < 64; ++i) {
RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], i);
t = S[7]; S[7] = S[6]; S[6] = S[5]; S[5] = S[4];
S[4] = S[3]; S[3] = S[2]; S[2] = S[1]; S[1] = S[0]; S[0] = t;
}
/* feedback */
for (i = 0; i < 8; i++) {
md->state[i] = md->state[i] + S[i];
}
return 0;
}
/* Initialize the hash state */
static void sha256_init(struct sha256_state *md)
{
md->curlen = 0;
md->length = 0;
md->state[0] = 0x6A09E667UL;
md->state[1] = 0xBB67AE85UL;
md->state[2] = 0x3C6EF372UL;
md->state[3] = 0xA54FF53AUL;
md->state[4] = 0x510E527FUL;
md->state[5] = 0x9B05688CUL;
md->state[6] = 0x1F83D9ABUL;
md->state[7] = 0x5BE0CD19UL;
}
/**
Process a block of memory though the hash
@param md The hash state
@param in The data to hash
@param inlen The length of the data (octets)
@return CRYPT_OK if successful
*/
static int sha256_process(struct sha256_state *md, const unsigned char *in,
unsigned long inlen)
{
unsigned long n;
#define block_size 64
if (md->curlen > sizeof(md->buf))
return -1;
while (inlen > 0) {
if (md->curlen == 0 && inlen >= block_size) {
if (sha256_compress(md, (unsigned char *) in) < 0)
return -1;
md->length += block_size * 8;
in += block_size;
inlen -= block_size;
} else {
n = MIN(inlen, (block_size - md->curlen));
memcpy(md->buf + md->curlen, in, n);
md->curlen += n;
in += n;
inlen -= n;
if (md->curlen == block_size) {
if (sha256_compress(md, md->buf) < 0)
return -1;
md->length += 8 * block_size;
md->curlen = 0;
}
}
}
return 0;
}
/**
Terminate the hash to get the digest
@param md The hash state
@param out [out] The destination of the hash (32 bytes)
@return CRYPT_OK if successful
*/
static int sha256_done(struct sha256_state *md, unsigned char *out)
{
int i;
if (md->curlen >= sizeof(md->buf))
return -1;
/* increase the length of the message */
md->length += md->curlen * 8;
/* append the '1' bit */
md->buf[md->curlen++] = (unsigned char) 0x80;
/* if the length is currently above 56 bytes we append zeros
* then compress. Then we can fall back to padding zeros and length
* encoding like normal.
*/
if (md->curlen > 56) {
while (md->curlen < 64) {
md->buf[md->curlen++] = (unsigned char) 0;
}
sha256_compress(md, md->buf);
md->curlen = 0;
}
/* pad upto 56 bytes of zeroes */
while (md->curlen < 56) {
md->buf[md->curlen++] = (unsigned char) 0;
}
/* store length */
WPA_PUT_BE64(md->buf + 56, md->length);
sha256_compress(md, md->buf);
/* copy output */
for (i = 0; i < 8; i++)
WPA_PUT_BE32(out + (4 * i), md->state[i]);
return 0;
}
/* ===== end - public domain SHA256 implementation ===== */
#endif /* INTERNAL_SHA256 */