Michael Rash
3095f0ee43
Added --key-gen to allow KEY_BASE64 and HMAC_KEY_BASE64 keys to be created from reading random data from /dev/random. These keys can be placed within server access.conf files and corresponding client .fwknoprc files for SPA communications. The HMAC key is not used yet with this commit, but that is coming.
283 lines
6.7 KiB
C
283 lines
6.7 KiB
C
/*
|
|
*****************************************************************************
|
|
*
|
|
* File: cipher_funcs.c
|
|
*
|
|
* Author: Damien S. Stuart
|
|
*
|
|
* Purpose: Cipher functions used by fwknop
|
|
*
|
|
* Copyright 2009-2010 Damien Stuart (dstuart@dstuart.org)
|
|
*
|
|
* License (GNU Public License):
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2
|
|
* of the License, or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
|
|
* USA
|
|
*
|
|
*****************************************************************************
|
|
*/
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
#ifdef WIN32
|
|
#include <sys/timeb.h>
|
|
#include <time.h>
|
|
#include <stdlib.h>
|
|
#else
|
|
#include <sys/time.h>
|
|
#endif
|
|
|
|
#include "cipher_funcs.h"
|
|
#include "digest.h"
|
|
|
|
#ifndef WIN32
|
|
#ifndef RAND_FILE
|
|
#define RAND_FILE "/dev/urandom"
|
|
#endif
|
|
#endif
|
|
|
|
/* Get random data.
|
|
*/
|
|
void
|
|
get_random_data(unsigned char *data, const size_t len)
|
|
{
|
|
uint32_t i;
|
|
#ifdef WIN32
|
|
int rnum;
|
|
struct _timeb tb;
|
|
|
|
_ftime_s(&tb);
|
|
|
|
srand((uint32_t)(tb.time*1000)+tb.millitm);
|
|
|
|
for(i=0; i<len; i++)
|
|
{
|
|
rnum = rand();
|
|
*(data+i) = rnum % 0xff;
|
|
}
|
|
#else
|
|
FILE *rfd;
|
|
struct timeval tv;
|
|
int do_time = 0;
|
|
size_t amt_read;
|
|
|
|
/* Attempt to read seed data from /dev/urandom. If that does not
|
|
* work, then fall back to a time-based method (less secure, but
|
|
* probably more portable).
|
|
*/
|
|
if((rfd = fopen(RAND_FILE, "r")) == NULL)
|
|
{
|
|
do_time = 1;
|
|
}
|
|
else
|
|
{
|
|
/* Read seed from /dev/urandom
|
|
*/
|
|
amt_read = fread(data, len, 1, rfd);
|
|
fclose(rfd);
|
|
|
|
if (amt_read != 1)
|
|
do_time = 1;
|
|
}
|
|
|
|
if (do_time)
|
|
{
|
|
/* Seed based on time (current usecs).
|
|
*/
|
|
gettimeofday(&tv, NULL);
|
|
srand(tv.tv_usec);
|
|
|
|
for(i=0; i<len; i++)
|
|
*(data+i) = rand() % 0xff;
|
|
}
|
|
|
|
#endif
|
|
|
|
}
|
|
|
|
|
|
/*** These are Rijndael-specific functions ***/
|
|
|
|
/* Rijndael function to generate initial salt and initialization vector
|
|
* (iv). This is is done to be compatible with the data produced via
|
|
* the Perl Crypt::CBC module's use of Rijndael.
|
|
*/
|
|
static void
|
|
rij_salt_and_iv(RIJNDAEL_context *ctx, const char *pass, const unsigned char *data)
|
|
{
|
|
char pw_buf[16];
|
|
unsigned char tmp_buf[64]; /* How big does this need to be? */
|
|
unsigned char kiv_buf[48]; /* Key and IV buffer */
|
|
unsigned char md5_buf[16]; /* Buffer for computed md5 hash */
|
|
|
|
size_t kiv_len = 0;
|
|
size_t plen = strlen(pass);
|
|
|
|
/* First make pw 16 bytes (pad with "0" (ascii 0x30)) or truncate.
|
|
* Note: pw_buf was initialized with '0' chars (again, not the value
|
|
* 0, but the digit '0' character).
|
|
*/
|
|
if(plen < 16)
|
|
{
|
|
memcpy(pw_buf, pass, plen);
|
|
memset(pw_buf+plen, '0', 16 - plen);
|
|
}
|
|
else
|
|
strncpy(pw_buf, pass, 16);
|
|
|
|
/* If we are decrypting, data will contain the salt. Otherwise,
|
|
* for encryption, we generate a random salt.
|
|
*/
|
|
if(data != NULL)
|
|
{
|
|
/* Pull the salt from the data
|
|
*/
|
|
memcpy(ctx->salt, (data+8), 8);
|
|
}
|
|
else
|
|
{
|
|
/* Generate a random 8-byte salt.
|
|
*/
|
|
get_random_data(ctx->salt, 8);
|
|
}
|
|
|
|
/* Now generate the key and initialization vector.
|
|
* (again it is the perl Crypt::CBC way, with a touch of
|
|
* fwknop).
|
|
*/
|
|
memcpy(tmp_buf+16, pw_buf, 16);
|
|
memcpy(tmp_buf+32, ctx->salt, 8);
|
|
|
|
while(kiv_len < sizeof(kiv_buf))
|
|
{
|
|
if(kiv_len == 0)
|
|
md5(md5_buf, tmp_buf+16, 24);
|
|
else
|
|
md5(md5_buf, tmp_buf, 40);
|
|
|
|
memcpy(tmp_buf, md5_buf, 16);
|
|
|
|
memcpy(kiv_buf + kiv_len, md5_buf, 16);
|
|
|
|
kiv_len += 16;
|
|
}
|
|
|
|
memcpy(ctx->key, kiv_buf, 32);
|
|
memcpy(ctx->iv, kiv_buf+32, 16);
|
|
}
|
|
|
|
/* Initialization entry point.
|
|
*/
|
|
static void
|
|
rijndael_init(RIJNDAEL_context *ctx, const char *pass,
|
|
const unsigned char *data, int encryption_mode)
|
|
{
|
|
|
|
/* The default (set in fko.h) is ECB mode to be compatible with the
|
|
* Crypt::CBC perl module.
|
|
*/
|
|
ctx->mode = encryption_mode;
|
|
|
|
/* Generate the salt and initialization vector.
|
|
*/
|
|
rij_salt_and_iv(ctx, pass, data);
|
|
|
|
/* Intialize our rinjdael context.
|
|
*/
|
|
rijndael_setup(ctx, 32, ctx->key);
|
|
}
|
|
|
|
/* Take a chunk of data, encrypt it in the same way the perl Crypt::CBC
|
|
* module would.
|
|
*/
|
|
size_t
|
|
rij_encrypt(unsigned char *in, size_t in_len,
|
|
const char *pass, unsigned char *out, int encryption_mode)
|
|
{
|
|
RIJNDAEL_context ctx;
|
|
int i, pad_val;
|
|
unsigned char *ondx = out;
|
|
|
|
rijndael_init(&ctx, pass, NULL, encryption_mode);
|
|
|
|
/* Prepend the salt to the ciphertext...
|
|
*/
|
|
memcpy(ondx, "Salted__", 8);
|
|
ondx+=8;
|
|
memcpy(ondx, ctx.salt, 8);
|
|
ondx+=8;
|
|
|
|
/* Add padding to the original plaintext to ensure that it is a
|
|
* multiple of the Rijndael block size
|
|
*/
|
|
pad_val = RIJNDAEL_BLOCKSIZE - (in_len % RIJNDAEL_BLOCKSIZE);
|
|
for (i = in_len; i < in_len+pad_val; i++)
|
|
in[i] = pad_val;
|
|
|
|
block_encrypt(&ctx, in, in_len+pad_val, ondx, ctx.iv);
|
|
|
|
ondx += in_len+pad_val;
|
|
|
|
return(ondx - out);
|
|
}
|
|
|
|
/* Decrypt the given data.
|
|
*/
|
|
size_t
|
|
rij_decrypt(unsigned char *in, size_t in_len,
|
|
const char *pass, unsigned char *out, int encryption_mode)
|
|
{
|
|
RIJNDAEL_context ctx;
|
|
int i, pad_val, pad_err = 0;
|
|
unsigned char *pad_s;
|
|
unsigned char *ondx = out;
|
|
|
|
rijndael_init(&ctx, pass, in, encryption_mode);
|
|
|
|
/* Remove the first block since it contains the salt (it was consumed
|
|
* by the rijndael_init() function above).
|
|
*/
|
|
in_len -= RIJNDAEL_BLOCKSIZE;
|
|
memmove(in, in+RIJNDAEL_BLOCKSIZE, in_len);
|
|
|
|
block_decrypt(&ctx, in, in_len, out, ctx.iv);
|
|
|
|
ondx += in_len;
|
|
|
|
/* Find and remove padding.
|
|
*/
|
|
pad_val = *(ondx-1);
|
|
|
|
if(pad_val >= 0 && pad_val <= RIJNDAEL_BLOCKSIZE)
|
|
{
|
|
pad_s = ondx - pad_val;
|
|
|
|
for(i=0; i < (ondx-pad_s); i++)
|
|
{
|
|
if(*(pad_s+i) != pad_val)
|
|
pad_err++;
|
|
}
|
|
|
|
if(pad_err == 0)
|
|
ondx -= pad_val;
|
|
}
|
|
|
|
*ondx = '\0';
|
|
|
|
return(ondx - out);
|
|
}
|
|
|
|
/***EOF***/
|