sha1.c

/*
 * 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 "sha1.h"


/* ===== start - public domain SHA1 implementation ===== */

/*
SHA-1 in C
By Steve Reid <sreid@sea-to-sky.net>
100% Public Domain

-----------------
Modified 7/98 
By James H. Brown <jbrown@burgoyne.com>
Still 100% Public Domain

Corrected a problem which generated improper hash values on 16 bit machines
Routine SHA1Update changed from
	void SHA1Update(SHA1_CTX* context, unsigned char* data, unsigned int
len)
to
	void SHA1Update(SHA1_CTX* context, unsigned char* data, unsigned
long len)

The 'len' parameter was declared an int which works fine on 32 bit machines.
However, on 16 bit machines an int is too small for the shifts being done
against
it.  This caused the hash function to generate incorrect values if len was
greater than 8191 (8K - 1) due to the 'len << 3' on line 3 of SHA1Update().

Since the file IO in main() reads 16K at a time, any file 8K or larger would
be guaranteed to generate the wrong hash (e.g. Test Vector #3, a million
"a"s).

I also changed the declaration of variables i & j in SHA1Update to 
unsigned long from unsigned int for the same reason.

These changes should make no difference to any 32 bit implementations since
an
int and a long are the same size in those environments.

--
I also corrected a few compiler warnings generated by Borland C.
1. Added #include <process.h> for exit() prototype
2. Removed unused variable 'j' in SHA1Final
3. Changed exit(0) to return(0) at end of main.

ALL changes I made can be located by searching for comments containing 'JHB'
-----------------
Modified 8/98
By Steve Reid <sreid@sea-to-sky.net>
Still 100% public domain

1- Removed #include <process.h> and used return() instead of exit()
2- Fixed overwriting of finalcount in SHA1Final() (discovered by Chris Hall)
3- Changed email address from steve@edmweb.com to sreid@sea-to-sky.net

-----------------
Modified 4/01
By Saul Kravitz <Saul.Kravitz@celera.com>
Still 100% PD
Modified to run on Compaq Alpha hardware.  

-----------------
Modified 4/01
By Jouni Malinen <j@w1.fi>
Minor changes to match the coding style used in Dynamics.

Modified September 24, 2004
By Jouni Malinen <j@w1.fi>
Fixed alignment issue in SHA1Transform when SHA1HANDSOFF is defined.

*/

/*
Test Vectors (from FIPS PUB 180-1)
"abc"
  A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D
"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"
  84983E44 1C3BD26E BAAE4AA1 F95129E5 E54670F1
A million repetitions of "a"
  34AA973C D4C4DAA4 F61EEB2B DBAD2731 6534016F
*/

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
#define blk0(i) (block->l[i] = blk0_endiansafe (block->l[i]))

#define blk(i) (block->l[i & 15] = rol(block->l[(i + 13) & 15] ^ \
	block->l[(i + 8) & 15] ^ block->l[(i + 2) & 15] ^ block->l[i & 15], 1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) \
	z += ((w & (x ^ y)) ^ y) + blk0(i) + 0x5A827999 + rol(v, 5); \
	w = rol(w, 30);
#define R1(v,w,x,y,z,i) \
	z += ((w & (x ^ y)) ^ y) + blk(i) + 0x5A827999 + rol(v, 5); \
	w = rol(w, 30);
#define R2(v,w,x,y,z,i) \
	z += (w ^ x ^ y) + blk(i) + 0x6ED9EBA1 + rol(v, 5); w = rol(w, 30);
#define R3(v,w,x,y,z,i) \
	z += (((w | x) & y) | (w & x)) + blk(i) + 0x8F1BBCDC + rol(v, 5); \
	w = rol(w, 30);
#define R4(v,w,x,y,z,i) \
	z += (w ^ x ^ y) + blk(i) + 0xCA62C1D6 + rol(v, 5); \
	w=rol(w, 30);

static void SHA1Transform(uint32_t state[5], const unsigned char buffer[64]);
/* Hash a single 512-bit block. This is the core of the algorithm. */

static int am_big_endian(void)
{
  long one= 1;
  return !(*((char *)(&one)));
}

static uint32_t blk0_endiansafe (uint32_t l)
{
  if (am_big_endian ())
    return l;
  else
    return (rol(l, 24) & 0xFF00FF00) | (rol(l, 8) & 0x00FF00FF);
}

static void SHA1Transform(uint32_t state[5], const unsigned char buffer[64])
{
  uint32_t a, b, c, d, e;
  typedef union {
    uint8_t c[64];
    uint32_t l[16];
  } CHAR64LONG16;
  CHAR64LONG16* block;
  uint8_t workspace[64];
  block = (CHAR64LONG16 *) workspace;
  memcpy(block, buffer, 64);

  /* Copy context->state[] to working vars */
  a = state[0];
  b = state[1];
  c = state[2];
  d = state[3];
  e = state[4];
  /* 4 rounds of 20 operations each. Loop unrolled. */
  R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
  R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
  R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
  R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
  R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
  R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
  R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
  R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
  R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
  R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
  R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
  R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
  R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
  R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
  R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
  R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
  R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
  R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
  R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
  R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);
  /* Add the working vars back into context.state[] */
  state[0] += a;
  state[1] += b;
  state[2] += c;
  state[3] += d;
  state[4] += e;
  /* Wipe variables */
  a = b = c = d = e = 0;
  memset(block, 0, 64);
}


/* SHA1Init - Initialize new context */

void SHA1Init(SHA1_CTX* context)
{
  /* SHA1 initialization constants */
  context->state[0] = 0x67452301;
  context->state[1] = 0xEFCDAB89;
  context->state[2] = 0x98BADCFE;
  context->state[3] = 0x10325476;
  context->state[4] = 0xC3D2E1F0;
  context->count[0] = context->count[1] = 0;
}


/* Run your data through this. */

void SHA1Update(SHA1_CTX* context, const void *_data, uint32_t len)
{
  uint32_t i, j;
  const unsigned char *data = _data;

  j = (context->count[0] >> 3) & 63;
  if ((context->count[0] += len << 3) < (len << 3))
    context->count[1]++;
  context->count[1] += (len >> 29);
  if ((j + len) > 63) {
    memcpy(&context->buffer[j], data, (i = 64-j));
    SHA1Transform(context->state, context->buffer);
    for ( ; i + 63 < len; i += 64) {
      SHA1Transform(context->state, &data[i]);
    }
    j = 0;
  }
  else i = 0;
  memcpy(&context->buffer[j], &data[i], len - i);
}


/* Add padding and return the message digest. */

void SHA1Final(unsigned char digest[20], SHA1_CTX* context)
{
  uint32_t i;
  unsigned char finalcount[8];

  for (i = 0; i < 8; i++) {
    finalcount[i] = (unsigned char)
        ((context->count[(i >= 4 ? 0 : 1)] >>
            ((3-(i & 3)) * 8) ) & 255);  /* Endian independent */
  }
  SHA1Update(context, (unsigned char *) "\200", 1);
  while ((context->count[0] & 504) != 448) {
    SHA1Update(context, (unsigned char *) "\0", 1);
  }
  SHA1Update(context, finalcount, 8);  /* Should cause a SHA1Transform()
					      */
  for (i = 0; i < 20; i++) {
    digest[i] = (unsigned char)
        ((context->state[i >> 2] >> ((3 - (i & 3)) * 8)) &
            255);
  }
  /* Wipe variables */
  i = 0;
  memset(context->buffer, 0, 64);
  memset(context->state, 0, 20);
  memset(context->count, 0, 8);
  memset(finalcount, 0, 8);
}

/* ===== end - public domain SHA1 implementation ===== */



/**
 * hmac_sha1_vector:
 * @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)
 *
 * HMAC-SHA1 over data vector (RFC 2104)
 */
void hmac_sha1_vector(const uint8_t *key, size_t key_len, size_t num_elem,
    const uint8_t *addr[], const size_t *len, uint8_t *mac)
{
  unsigned char k_pad[64]; /* padding - key XORd with ipad/opad */
  unsigned char tk[20];
  const uint8_t *_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 = SHA1(key) */
  if (key_len > 64) {
    sha1_vector(1, &key, &key_len, tk);
    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 */
  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 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];
  }
  sha1_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 SHA1 */
  _addr[0] = k_pad;
  _len[0] = 64;
  _addr[1] = mac;
  _len[1] = SHA1_MAC_LEN;
  sha1_vector(2, _addr, _len, mac);
}


/**
 * hmac_sha1:
 * @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)
 *
 * HMAC-SHA1 over data buffer (RFC 2104)
 */
void hmac_sha1(const uint8_t *key, size_t key_len,
    const uint8_t *data, size_t data_len, uint8_t *mac)
{
  hmac_sha1_vector(key, key_len, 1, &data, &data_len, mac);
}


/**
 * sha1_prf:
 * @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
 *
 * SHA1-based Pseudo-Random Function (PRF) (IEEE 802.11i, 8.5.1.1)
 *
 * This function is used to derive new, cryptographically separate keys from a
 * given key (e.g., PMK in IEEE 802.11i).
 */
void sha1_prf(const uint8_t *key, size_t key_len, const char *label,
    const uint8_t *data, size_t data_len, uint8_t *buf, size_t buf_len)
{
  uint8_t counter = 0;
  size_t pos, plen;
  uint8_t hash[SHA1_MAC_LEN];
  size_t label_len = strlen(label) + 1;
  const unsigned char *addr[3];
  size_t len[3];

  addr[0] = (uint8_t *) 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) {
      hmac_sha1_vector(key, key_len, 3, addr, len, &buf[pos]);
      pos += SHA1_MAC_LEN;
    } else {
      hmac_sha1_vector(key, key_len, 3, addr, len, hash);
      memcpy(&buf[pos], hash, plen);
      break;
    }
    counter++;
  }
}

/**
 * sha1_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
 *
 * SHA-1 hash for data vector
 */
void sha1_vector(size_t num_elem, const uint8_t *addr[], const size_t *len,
    uint8_t *mac)
{
  SHA1_CTX ctx;
  size_t i;

  SHA1Init(&ctx);
  for (i = 0; i < num_elem; i++)
    SHA1Update(&ctx, addr[i], len[i]);
  SHA1Final(mac, &ctx);
}