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pgp.h used to require including mbuf.h and px.h first. Include those in pgp.h, so that it can be used without prerequisites. Remove mbuf.h inclusions in .c files where mbuf.h features are not used directly. (px.h was always used.)
308 lines
6.4 KiB
C
308 lines
6.4 KiB
C
/*
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* pgp-mpi-internal.c
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* OpenPGP MPI functions.
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*
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* Copyright (c) 2005 Marko Kreen
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* contrib/pgcrypto/pgp-mpi-internal.c
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*/
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#include "postgres.h"
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#include "imath.h"
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#include "px.h"
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#include "pgp.h"
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static mpz_t *
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mp_new()
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{
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mpz_t *mp = mp_int_alloc();
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mp_int_init_size(mp, 256);
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return mp;
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}
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static void
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mp_clear_free(mpz_t *a)
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{
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if (!a)
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return;
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/* fixme: no clear? */
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mp_int_free(a);
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}
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static int
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mp_px_rand(uint32 bits, mpz_t *res)
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{
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int err;
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unsigned bytes = (bits + 7) / 8;
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int last_bits = bits & 7;
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uint8 *buf;
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buf = px_alloc(bytes);
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err = px_get_random_bytes(buf, bytes);
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if (err < 0)
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{
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px_free(buf);
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return err;
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}
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/* clear unnecessary bits and set last bit to one */
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if (last_bits)
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{
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buf[0] >>= 8 - last_bits;
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buf[0] |= 1 << (last_bits - 1);
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}
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else
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buf[0] |= 1 << 7;
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mp_int_read_unsigned(res, buf, bytes);
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px_free(buf);
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return 0;
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}
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static void
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mp_modmul(mpz_t *a, mpz_t *b, mpz_t *p, mpz_t *res)
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{
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mpz_t *tmp = mp_new();
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mp_int_mul(a, b, tmp);
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mp_int_mod(tmp, p, res);
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mp_clear_free(tmp);
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}
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static mpz_t *
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mpi_to_bn(PGP_MPI *n)
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{
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mpz_t *bn = mp_new();
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mp_int_read_unsigned(bn, n->data, n->bytes);
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if (!bn)
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return NULL;
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if (mp_int_count_bits(bn) != n->bits)
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{
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px_debug("mpi_to_bn: bignum conversion failed: mpi=%d, bn=%d",
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n->bits, mp_int_count_bits(bn));
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mp_clear_free(bn);
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return NULL;
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}
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return bn;
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}
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static PGP_MPI *
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bn_to_mpi(mpz_t *bn)
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{
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int res;
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PGP_MPI *n;
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int bytes;
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res = pgp_mpi_alloc(mp_int_count_bits(bn), &n);
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if (res < 0)
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return NULL;
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bytes = (mp_int_count_bits(bn) + 7) / 8;
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if (bytes != n->bytes)
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{
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px_debug("bn_to_mpi: bignum conversion failed: bn=%d, mpi=%d",
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bytes, n->bytes);
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pgp_mpi_free(n);
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return NULL;
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}
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mp_int_to_unsigned(bn, n->data, n->bytes);
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return n;
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}
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/*
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* Decide the number of bits in the random componont k
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*
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* It should be in the same range as p for signing (which
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* is deprecated), but can be much smaller for encrypting.
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*
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* Until I research it further, I just mimic gpg behaviour.
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* It has a special mapping table, for values <= 5120,
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* above that it uses 'arbitrary high number'. Following
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* algorihm hovers 10-70 bits above gpg values. And for
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* larger p, it uses gpg's algorihm.
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*
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* The point is - if k gets large, encryption will be
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* really slow. It does not matter for decryption.
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*/
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static int
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decide_k_bits(int p_bits)
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{
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if (p_bits <= 5120)
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return p_bits / 10 + 160;
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else
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return (p_bits / 8 + 200) * 3 / 2;
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}
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int
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pgp_elgamal_encrypt(PGP_PubKey *pk, PGP_MPI *_m,
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PGP_MPI **c1_p, PGP_MPI **c2_p)
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{
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int res = PXE_PGP_MATH_FAILED;
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int k_bits;
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mpz_t *m = mpi_to_bn(_m);
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mpz_t *p = mpi_to_bn(pk->pub.elg.p);
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mpz_t *g = mpi_to_bn(pk->pub.elg.g);
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mpz_t *y = mpi_to_bn(pk->pub.elg.y);
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mpz_t *k = mp_new();
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mpz_t *yk = mp_new();
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mpz_t *c1 = mp_new();
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mpz_t *c2 = mp_new();
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if (!m || !p || !g || !y || !k || !yk || !c1 || !c2)
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goto err;
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/*
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* generate k
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*/
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k_bits = decide_k_bits(mp_int_count_bits(p));
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res = mp_px_rand(k_bits, k);
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if (res < 0)
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return res;
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/*
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* c1 = g^k c2 = m * y^k
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*/
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mp_int_exptmod(g, k, p, c1);
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mp_int_exptmod(y, k, p, yk);
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mp_modmul(m, yk, p, c2);
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/* result */
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*c1_p = bn_to_mpi(c1);
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*c2_p = bn_to_mpi(c2);
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if (*c1_p && *c2_p)
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res = 0;
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err:
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mp_clear_free(c2);
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mp_clear_free(c1);
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mp_clear_free(yk);
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mp_clear_free(k);
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mp_clear_free(y);
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mp_clear_free(g);
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mp_clear_free(p);
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mp_clear_free(m);
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return res;
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}
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int
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pgp_elgamal_decrypt(PGP_PubKey *pk, PGP_MPI *_c1, PGP_MPI *_c2,
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PGP_MPI **msg_p)
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{
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int res = PXE_PGP_MATH_FAILED;
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mpz_t *c1 = mpi_to_bn(_c1);
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mpz_t *c2 = mpi_to_bn(_c2);
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mpz_t *p = mpi_to_bn(pk->pub.elg.p);
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mpz_t *x = mpi_to_bn(pk->sec.elg.x);
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mpz_t *c1x = mp_new();
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mpz_t *div = mp_new();
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mpz_t *m = mp_new();
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if (!c1 || !c2 || !p || !x || !c1x || !div || !m)
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goto err;
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/*
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* m = c2 / (c1^x)
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*/
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mp_int_exptmod(c1, x, p, c1x);
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mp_int_invmod(c1x, p, div);
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mp_modmul(c2, div, p, m);
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/* result */
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*msg_p = bn_to_mpi(m);
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if (*msg_p)
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res = 0;
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err:
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mp_clear_free(m);
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mp_clear_free(div);
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mp_clear_free(c1x);
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mp_clear_free(x);
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mp_clear_free(p);
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mp_clear_free(c2);
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mp_clear_free(c1);
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return res;
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}
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int
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pgp_rsa_encrypt(PGP_PubKey *pk, PGP_MPI *_m, PGP_MPI **c_p)
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{
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int res = PXE_PGP_MATH_FAILED;
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mpz_t *m = mpi_to_bn(_m);
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mpz_t *e = mpi_to_bn(pk->pub.rsa.e);
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mpz_t *n = mpi_to_bn(pk->pub.rsa.n);
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mpz_t *c = mp_new();
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if (!m || !e || !n || !c)
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goto err;
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/*
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* c = m ^ e
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*/
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mp_int_exptmod(m, e, n, c);
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*c_p = bn_to_mpi(c);
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if (*c_p)
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res = 0;
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err:
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mp_clear_free(c);
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mp_clear_free(n);
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mp_clear_free(e);
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mp_clear_free(m);
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return res;
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}
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int
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pgp_rsa_decrypt(PGP_PubKey *pk, PGP_MPI *_c, PGP_MPI **m_p)
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{
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int res = PXE_PGP_MATH_FAILED;
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mpz_t *c = mpi_to_bn(_c);
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mpz_t *d = mpi_to_bn(pk->sec.rsa.d);
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mpz_t *n = mpi_to_bn(pk->pub.rsa.n);
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mpz_t *m = mp_new();
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if (!m || !d || !n || !c)
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goto err;
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/*
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* m = c ^ d
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*/
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mp_int_exptmod(c, d, n, m);
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*m_p = bn_to_mpi(m);
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if (*m_p)
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res = 0;
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err:
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mp_clear_free(m);
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mp_clear_free(n);
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mp_clear_free(d);
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mp_clear_free(c);
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return res;
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}
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