postgresql/contrib/pgcrypto/px-hmac.c
2010-09-20 22:08:53 +02:00

180 lines
3.6 KiB
C

/*
* px-hmac.c
* HMAC implementation.
*
* Copyright (c) 2001 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.
*
* contrib/pgcrypto/px-hmac.c
*/
#include "postgres.h"
#include "px.h"
#define HMAC_IPAD 0x36
#define HMAC_OPAD 0x5C
static unsigned
hmac_result_size(PX_HMAC *h)
{
return px_md_result_size(h->md);
}
static unsigned
hmac_block_size(PX_HMAC *h)
{
return px_md_block_size(h->md);
}
static void
hmac_init(PX_HMAC *h, const uint8 *key, unsigned klen)
{
unsigned bs,
hlen,
i;
uint8 *keybuf;
PX_MD *md = h->md;
bs = px_md_block_size(md);
hlen = px_md_result_size(md);
keybuf = px_alloc(bs);
memset(keybuf, 0, bs);
if (klen > bs)
{
px_md_update(md, key, klen);
px_md_finish(md, keybuf);
px_md_reset(md);
}
else
memcpy(keybuf, key, klen);
for (i = 0; i < bs; i++)
{
h->p.ipad[i] = keybuf[i] ^ HMAC_IPAD;
h->p.opad[i] = keybuf[i] ^ HMAC_OPAD;
}
memset(keybuf, 0, bs);
px_free(keybuf);
px_md_update(md, h->p.ipad, bs);
}
static void
hmac_reset(PX_HMAC *h)
{
PX_MD *md = h->md;
unsigned bs = px_md_block_size(md);
px_md_reset(md);
px_md_update(md, h->p.ipad, bs);
}
static void
hmac_update(PX_HMAC *h, const uint8 *data, unsigned dlen)
{
px_md_update(h->md, data, dlen);
}
static void
hmac_finish(PX_HMAC *h, uint8 *dst)
{
PX_MD *md = h->md;
unsigned bs,
hlen;
uint8 *buf;
bs = px_md_block_size(md);
hlen = px_md_result_size(md);
buf = px_alloc(hlen);
px_md_finish(md, buf);
px_md_reset(md);
px_md_update(md, h->p.opad, bs);
px_md_update(md, buf, hlen);
px_md_finish(md, dst);
memset(buf, 0, hlen);
px_free(buf);
}
static void
hmac_free(PX_HMAC *h)
{
unsigned bs;
bs = px_md_block_size(h->md);
px_md_free(h->md);
memset(h->p.ipad, 0, bs);
memset(h->p.opad, 0, bs);
px_free(h->p.ipad);
px_free(h->p.opad);
px_free(h);
}
/* PUBLIC FUNCTIONS */
int
px_find_hmac(const char *name, PX_HMAC **res)
{
int err;
PX_MD *md;
PX_HMAC *h;
unsigned bs;
err = px_find_digest(name, &md);
if (err)
return err;
bs = px_md_block_size(md);
if (bs < 2)
{
px_md_free(md);
return PXE_HASH_UNUSABLE_FOR_HMAC;
}
h = px_alloc(sizeof(*h));
h->p.ipad = px_alloc(bs);
h->p.opad = px_alloc(bs);
h->md = md;
h->result_size = hmac_result_size;
h->block_size = hmac_block_size;
h->reset = hmac_reset;
h->update = hmac_update;
h->finish = hmac_finish;
h->free = hmac_free;
h->init = hmac_init;
*res = h;
return 0;
}