postgresql/contrib/pgcrypto/pgp-mpi-internal.c
Amit Kapila 7e735035f2 Make the order of the header file includes consistent in contrib modules.
The basic rule we follow here is to always first include 'postgres.h' or
'postgres_fe.h' whichever is applicable, then system header includes and
then Postgres header includes.  In this, we also follow that all the
Postgres header includes are in order based on their ASCII value.  We
generally follow these rules, but the code has deviated in many places.
This commit makes it consistent just for contrib modules.  The later
commits will enforce similar rules in other parts of code.

Author: Vignesh C
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/CALDaNm2Sznv8RR6Ex-iJO6xAdsxgWhCoETkaYX=+9DW3q0QCfA@mail.gmail.com
2019-10-24 08:05:34 +05:30

305 lines
6.3 KiB
C

/*
* pgp-mpi-internal.c
* OpenPGP MPI 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.
*
* contrib/pgcrypto/pgp-mpi-internal.c
*/
#include "postgres.h"
#include "imath.h"
#include "pgp.h"
#include "px.h"
static mpz_t *
mp_new()
{
mpz_t *mp = mp_int_alloc();
mp_int_init_size(mp, 256);
return mp;
}
static void
mp_clear_free(mpz_t *a)
{
if (!a)
return;
/* fixme: no clear? */
mp_int_free(a);
}
static int
mp_px_rand(uint32 bits, mpz_t *res)
{
unsigned bytes = (bits + 7) / 8;
int last_bits = bits & 7;
uint8 *buf;
buf = px_alloc(bytes);
if (!pg_strong_random(buf, bytes))
{
px_free(buf);
return PXE_NO_RANDOM;
}
/* clear unnecessary bits and set last bit to one */
if (last_bits)
{
buf[0] >>= 8 - last_bits;
buf[0] |= 1 << (last_bits - 1);
}
else
buf[0] |= 1 << 7;
mp_int_read_unsigned(res, buf, bytes);
px_free(buf);
return 0;
}
static void
mp_modmul(mpz_t *a, mpz_t *b, mpz_t *p, mpz_t *res)
{
mpz_t *tmp = mp_new();
mp_int_mul(a, b, tmp);
mp_int_mod(tmp, p, res);
mp_clear_free(tmp);
}
static mpz_t *
mpi_to_bn(PGP_MPI *n)
{
mpz_t *bn = mp_new();
mp_int_read_unsigned(bn, n->data, n->bytes);
if (!bn)
return NULL;
if (mp_int_count_bits(bn) != n->bits)
{
px_debug("mpi_to_bn: bignum conversion failed: mpi=%d, bn=%d",
n->bits, mp_int_count_bits(bn));
mp_clear_free(bn);
return NULL;
}
return bn;
}
static PGP_MPI *
bn_to_mpi(mpz_t *bn)
{
int res;
PGP_MPI *n;
int bytes;
res = pgp_mpi_alloc(mp_int_count_bits(bn), &n);
if (res < 0)
return NULL;
bytes = (mp_int_count_bits(bn) + 7) / 8;
if (bytes != n->bytes)
{
px_debug("bn_to_mpi: bignum conversion failed: bn=%d, mpi=%d",
bytes, n->bytes);
pgp_mpi_free(n);
return NULL;
}
mp_int_to_unsigned(bn, n->data, n->bytes);
return n;
}
/*
* Decide the number of bits in the random component k
*
* It should be in the same range as p for signing (which
* is deprecated), but can be much smaller for encrypting.
*
* Until I research it further, I just mimic gpg behaviour.
* It has a special mapping table, for values <= 5120,
* above that it uses 'arbitrary high number'. Following
* algorithm hovers 10-70 bits above gpg values. And for
* larger p, it uses gpg's algorithm.
*
* The point is - if k gets large, encryption will be
* really slow. It does not matter for decryption.
*/
static int
decide_k_bits(int p_bits)
{
if (p_bits <= 5120)
return p_bits / 10 + 160;
else
return (p_bits / 8 + 200) * 3 / 2;
}
int
pgp_elgamal_encrypt(PGP_PubKey *pk, PGP_MPI *_m,
PGP_MPI **c1_p, PGP_MPI **c2_p)
{
int res = PXE_PGP_MATH_FAILED;
int k_bits;
mpz_t *m = mpi_to_bn(_m);
mpz_t *p = mpi_to_bn(pk->pub.elg.p);
mpz_t *g = mpi_to_bn(pk->pub.elg.g);
mpz_t *y = mpi_to_bn(pk->pub.elg.y);
mpz_t *k = mp_new();
mpz_t *yk = mp_new();
mpz_t *c1 = mp_new();
mpz_t *c2 = mp_new();
if (!m || !p || !g || !y || !k || !yk || !c1 || !c2)
goto err;
/*
* generate k
*/
k_bits = decide_k_bits(mp_int_count_bits(p));
res = mp_px_rand(k_bits, k);
if (res < 0)
return res;
/*
* c1 = g^k c2 = m * y^k
*/
mp_int_exptmod(g, k, p, c1);
mp_int_exptmod(y, k, p, yk);
mp_modmul(m, yk, p, c2);
/* result */
*c1_p = bn_to_mpi(c1);
*c2_p = bn_to_mpi(c2);
if (*c1_p && *c2_p)
res = 0;
err:
mp_clear_free(c2);
mp_clear_free(c1);
mp_clear_free(yk);
mp_clear_free(k);
mp_clear_free(y);
mp_clear_free(g);
mp_clear_free(p);
mp_clear_free(m);
return res;
}
int
pgp_elgamal_decrypt(PGP_PubKey *pk, PGP_MPI *_c1, PGP_MPI *_c2,
PGP_MPI **msg_p)
{
int res = PXE_PGP_MATH_FAILED;
mpz_t *c1 = mpi_to_bn(_c1);
mpz_t *c2 = mpi_to_bn(_c2);
mpz_t *p = mpi_to_bn(pk->pub.elg.p);
mpz_t *x = mpi_to_bn(pk->sec.elg.x);
mpz_t *c1x = mp_new();
mpz_t *div = mp_new();
mpz_t *m = mp_new();
if (!c1 || !c2 || !p || !x || !c1x || !div || !m)
goto err;
/*
* m = c2 / (c1^x)
*/
mp_int_exptmod(c1, x, p, c1x);
mp_int_invmod(c1x, p, div);
mp_modmul(c2, div, p, m);
/* result */
*msg_p = bn_to_mpi(m);
if (*msg_p)
res = 0;
err:
mp_clear_free(m);
mp_clear_free(div);
mp_clear_free(c1x);
mp_clear_free(x);
mp_clear_free(p);
mp_clear_free(c2);
mp_clear_free(c1);
return res;
}
int
pgp_rsa_encrypt(PGP_PubKey *pk, PGP_MPI *_m, PGP_MPI **c_p)
{
int res = PXE_PGP_MATH_FAILED;
mpz_t *m = mpi_to_bn(_m);
mpz_t *e = mpi_to_bn(pk->pub.rsa.e);
mpz_t *n = mpi_to_bn(pk->pub.rsa.n);
mpz_t *c = mp_new();
if (!m || !e || !n || !c)
goto err;
/*
* c = m ^ e
*/
mp_int_exptmod(m, e, n, c);
*c_p = bn_to_mpi(c);
if (*c_p)
res = 0;
err:
mp_clear_free(c);
mp_clear_free(n);
mp_clear_free(e);
mp_clear_free(m);
return res;
}
int
pgp_rsa_decrypt(PGP_PubKey *pk, PGP_MPI *_c, PGP_MPI **m_p)
{
int res = PXE_PGP_MATH_FAILED;
mpz_t *c = mpi_to_bn(_c);
mpz_t *d = mpi_to_bn(pk->sec.rsa.d);
mpz_t *n = mpi_to_bn(pk->pub.rsa.n);
mpz_t *m = mp_new();
if (!m || !d || !n || !c)
goto err;
/*
* m = c ^ d
*/
mp_int_exptmod(c, d, n, m);
*m_p = bn_to_mpi(m);
if (*m_p)
res = 0;
err:
mp_clear_free(m);
mp_clear_free(n);
mp_clear_free(d);
mp_clear_free(c);
return res;
}