postgresql/contrib/pgcrypto/pgp-s2k.c
2005-07-18 17:12:54 +00:00

300 lines
5.9 KiB
C

/*
* pgp-s2k.c
* OpenPGP string2key functions.
*
* Copyright (c) 2005 Marko Kreen
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $PostgreSQL: pgsql/contrib/pgcrypto/pgp-s2k.c,v 1.3 2005/07/18 17:12:54 tgl Exp $
*/
#include "postgres.h"
#include "px.h"
#include "mbuf.h"
#include "pgp.h"
static int
calc_s2k_simple(PGP_S2K * s2k, PX_MD *md, const uint8 *key,
unsigned key_len)
{
unsigned md_bs,
md_rlen;
uint8 buf[PGP_MAX_DIGEST];
unsigned preload;
unsigned remain;
uint8 *dst = s2k->key;
md_bs = px_md_block_size(md);
md_rlen = px_md_result_size(md);
remain = s2k->key_len;
preload = 0;
while (remain > 0)
{
px_md_reset(md);
if (preload)
{
memset(buf, 0, preload);
px_md_update(md, buf, preload);
}
preload++;
px_md_update(md, key, key_len);
px_md_finish(md, buf);
if (remain > md_rlen)
{
memcpy(dst, buf, md_rlen);
dst += md_rlen;
remain -= md_rlen;
}
else
{
memcpy(dst, buf, remain);
remain = 0;
}
}
return 0;
}
static int
calc_s2k_salted(PGP_S2K * s2k, PX_MD *md, const uint8 *key, unsigned key_len)
{
unsigned md_bs,
md_rlen;
uint8 buf[PGP_MAX_DIGEST];
unsigned preload = 0;
uint8 *dst;
unsigned remain;
md_bs = px_md_block_size(md);
md_rlen = px_md_result_size(md);
dst = s2k->key;
remain = s2k->key_len;
while (remain > 0)
{
px_md_reset(md);
if (preload > 0)
{
memset(buf, 0, preload);
px_md_update(md, buf, preload);
}
preload++;
px_md_update(md, s2k->salt, PGP_S2K_SALT);
px_md_update(md, key, key_len);
px_md_finish(md, buf);
if (remain > md_rlen)
{
memcpy(dst, buf, md_rlen);
remain -= md_rlen;
dst += md_rlen;
}
else
{
memcpy(dst, buf, remain);
remain = 0;
}
}
return 0;
}
static int
calc_s2k_iter_salted(PGP_S2K * s2k, PX_MD *md, const uint8 *key,
unsigned key_len)
{
unsigned md_bs,
md_rlen;
uint8 buf[PGP_MAX_DIGEST];
uint8 *dst;
unsigned preload = 0;
unsigned remain,
c,
cval,
curcnt,
count;
cval = s2k->iter;
count = ((unsigned) 16 + (cval & 15)) << ((cval >> 4) + 6);
md_bs = px_md_block_size(md);
md_rlen = px_md_result_size(md);
remain = s2k->key_len;
dst = s2k->key;
while (remain > 0)
{
px_md_reset(md);
if (preload)
{
memset(buf, 0, preload);
px_md_update(md, buf, preload);
}
preload++;
px_md_update(md, s2k->salt, PGP_S2K_SALT);
px_md_update(md, key, key_len);
curcnt = PGP_S2K_SALT + key_len;
while (curcnt < count)
{
if (curcnt + PGP_S2K_SALT < count)
c = PGP_S2K_SALT;
else
c = count - curcnt;
px_md_update(md, s2k->salt, c);
curcnt += c;
if (curcnt + key_len < count)
c = key_len;
else if (curcnt < count)
c = count - curcnt;
else
break;
px_md_update(md, key, c);
curcnt += c;
}
px_md_finish(md, buf);
if (remain > md_rlen)
{
memcpy(dst, buf, md_rlen);
remain -= md_rlen;
dst += md_rlen;
}
else
{
memcpy(dst, buf, remain);
remain = 0;
}
}
return 0;
}
/*
* Decide S2K_ISALTED iteration count
*
* Too small: weak
* Too big: slow
* gpg defaults to 96 => 65536 iters
* let it float a bit: 96 + 32 => 262144 iters
*/
static int
decide_count(unsigned rand_byte)
{
return 96 + (rand_byte & 0x1F);
}
int
pgp_s2k_fill(PGP_S2K *s2k, int mode,int digest_algo)
{
int res = 0;
uint8 tmp;
s2k->mode = mode;
s2k->digest_algo = digest_algo;
switch (s2k->mode) {
case 0:
break;
case 1:
res = px_get_pseudo_random_bytes(s2k->salt, PGP_S2K_SALT);
break;
case 3:
res = px_get_pseudo_random_bytes(s2k->salt, PGP_S2K_SALT);
if (res < 0)
break;
res = px_get_pseudo_random_bytes(&tmp, 1);
if (res < 0)
break;
s2k->iter = decide_count(tmp);
break;
default:
res = PXE_PGP_BAD_S2K_MODE;
}
return res;
}
int
pgp_s2k_read(PullFilter *src, PGP_S2K *s2k)
{
int res = 0;
GETBYTE(src, s2k->mode);
GETBYTE(src, s2k->digest_algo);
switch (s2k->mode) {
case 0:
break;
case 1:
res = pullf_read_fixed(src, 8, s2k->salt);
break;
case 3:
res = pullf_read_fixed(src, 8, s2k->salt);
if (res < 0)
break;
GETBYTE(src, s2k->iter);
break;
default:
res = PXE_PGP_BAD_S2K_MODE;
}
return res;
}
int pgp_s2k_process(PGP_S2K *s2k, int cipher, const uint8 *key, int key_len)
{
int res;
PX_MD *md;
s2k->key_len = pgp_get_cipher_key_size(cipher);
if (s2k->key_len <= 0)
return PXE_PGP_UNSUPPORTED_CIPHER;
res = pgp_load_digest(s2k->digest_algo, &md);
if (res < 0)
return res;
switch (s2k->mode) {
case 0:
res = calc_s2k_simple(s2k, md, key, key_len);
break;
case 1:
res = calc_s2k_salted(s2k, md, key, key_len);
break;
case 3:
res = calc_s2k_iter_salted(s2k, md, key, key_len);
break;
default:
res = PXE_PGP_BAD_S2K_MODE;
}
px_md_free(md);
return res;
}