diff options
Diffstat (limited to 'libotr/libgcrypt-1.8.7/mpi/mpi-mul.c')
| -rw-r--r-- | libotr/libgcrypt-1.8.7/mpi/mpi-mul.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/libotr/libgcrypt-1.8.7/mpi/mpi-mul.c b/libotr/libgcrypt-1.8.7/mpi/mpi-mul.c new file mode 100644 index 0000000..4f4d709 --- /dev/null +++ b/libotr/libgcrypt-1.8.7/mpi/mpi-mul.c @@ -0,0 +1,212 @@ +/* mpi-mul.c - MPI functions + * Copyright (C) 1994, 1996, 1998, 2001, 2002, 2003 Free Software Foundation, Inc. + * + * This file is part of Libgcrypt. + * + * Libgcrypt is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as + * published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * Libgcrypt 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 Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser 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 + * + * Note: This code is heavily based on the GNU MP Library. + * Actually it's the same code with only minor changes in the + * way the data is stored; this is to support the abstraction + * of an optional secure memory allocation which may be used + * to avoid revealing of sensitive data due to paging etc. + */ + +#include <config.h> +#include <stdio.h> +#include <stdlib.h> +#include "mpi-internal.h" + + +void +_gcry_mpi_mul_ui (gcry_mpi_t prod, gcry_mpi_t mult, unsigned long small_mult) +{ + mpi_size_t size, prod_size; + mpi_ptr_t prod_ptr; + mpi_limb_t cy; + int sign; + + size = mult->nlimbs; + sign = mult->sign; + + if( !size || !small_mult ) { + prod->nlimbs = 0; + prod->sign = 0; + return; + } + + prod_size = size + 1; + if( prod->alloced < prod_size ) + mpi_resize( prod, prod_size ); + prod_ptr = prod->d; + + cy = _gcry_mpih_mul_1( prod_ptr, mult->d, size, (mpi_limb_t)small_mult ); + if( cy ) + prod_ptr[size++] = cy; + prod->nlimbs = size; + prod->sign = sign; +} + + +void +_gcry_mpi_mul_2exp (gcry_mpi_t w, gcry_mpi_t u, unsigned long cnt) +{ + mpi_size_t usize, wsize, limb_cnt; + mpi_ptr_t wp; + mpi_limb_t wlimb; + int usign, wsign; + + usize = u->nlimbs; + usign = u->sign; + + if( !usize ) { + w->nlimbs = 0; + w->sign = 0; + return; + } + + limb_cnt = cnt / BITS_PER_MPI_LIMB; + wsize = usize + limb_cnt + 1; + if( w->alloced < wsize ) + mpi_resize(w, wsize ); + wp = w->d; + wsize = usize + limb_cnt; + wsign = usign; + + cnt %= BITS_PER_MPI_LIMB; + if( cnt ) { + wlimb = _gcry_mpih_lshift( wp + limb_cnt, u->d, usize, cnt ); + if( wlimb ) { + wp[wsize] = wlimb; + wsize++; + } + } + else { + MPN_COPY_DECR( wp + limb_cnt, u->d, usize ); + } + + /* Zero all whole limbs at low end. Do it here and not before calling + * mpn_lshift, not to lose for U == W. */ + MPN_ZERO( wp, limb_cnt ); + + w->nlimbs = wsize; + w->sign = wsign; +} + + +void +_gcry_mpi_mul (gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v) +{ + mpi_size_t usize, vsize, wsize; + mpi_ptr_t up, vp, wp; + mpi_limb_t cy; + int usign, vsign, usecure, vsecure, sign_product; + int assign_wp=0; + mpi_ptr_t tmp_limb=NULL; + unsigned int tmp_limb_nlimbs = 0; + + if( u->nlimbs < v->nlimbs ) { /* Swap U and V. */ + usize = v->nlimbs; + usign = v->sign; + usecure = mpi_is_secure(v); + up = v->d; + vsize = u->nlimbs; + vsign = u->sign; + vsecure = mpi_is_secure(u); + vp = u->d; + } + else { + usize = u->nlimbs; + usign = u->sign; + usecure = mpi_is_secure(u); + up = u->d; + vsize = v->nlimbs; + vsign = v->sign; + vsecure = mpi_is_secure(v); + vp = v->d; + } + sign_product = usign ^ vsign; + wp = w->d; + + /* Ensure W has space enough to store the result. */ + wsize = usize + vsize; + if ( !mpi_is_secure (w) && (mpi_is_secure (u) || mpi_is_secure (v)) ) { + /* w is not allocated in secure space but u or v is. To make sure + * that no temporray results are stored in w, we temporary use + * a newly allocated limb space for w */ + wp = mpi_alloc_limb_space( wsize, 1 ); + assign_wp = 2; /* mark it as 2 so that we can later copy it back to + * mormal memory */ + } + else if( w->alloced < wsize ) { + if( wp == up || wp == vp ) { + wp = mpi_alloc_limb_space( wsize, mpi_is_secure(w) ); + assign_wp = 1; + } + else { + mpi_resize(w, wsize ); + wp = w->d; + } + } + else { /* Make U and V not overlap with W. */ + if( wp == up ) { + /* W and U are identical. Allocate temporary space for U. */ + tmp_limb_nlimbs = usize; + up = tmp_limb = mpi_alloc_limb_space( usize, usecure ); + /* Is V identical too? Keep it identical with U. */ + if( wp == vp ) + vp = up; + /* Copy to the temporary space. */ + MPN_COPY( up, wp, usize ); + } + else if( wp == vp ) { + /* W and V are identical. Allocate temporary space for V. */ + tmp_limb_nlimbs = vsize; + vp = tmp_limb = mpi_alloc_limb_space( vsize, vsecure ); + /* Copy to the temporary space. */ + MPN_COPY( vp, wp, vsize ); + } + } + + if( !vsize ) + wsize = 0; + else { + cy = _gcry_mpih_mul( wp, up, usize, vp, vsize ); + wsize -= cy? 0:1; + } + + if( assign_wp ) { + if (assign_wp == 2) { + /* copy the temp wp from secure memory back to normal memory */ + mpi_ptr_t tmp_wp = mpi_alloc_limb_space (wsize, 0); + MPN_COPY (tmp_wp, wp, wsize); + _gcry_mpi_free_limb_space (wp, 0); + wp = tmp_wp; + } + _gcry_mpi_assign_limb_space( w, wp, wsize ); + } + w->nlimbs = wsize; + w->sign = sign_product; + if( tmp_limb ) + _gcry_mpi_free_limb_space (tmp_limb, tmp_limb_nlimbs); +} + + +void +_gcry_mpi_mulm (gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v, gcry_mpi_t m) +{ + mpi_mul (w, u, v); + _gcry_mpi_tdiv_r (w, w, m); +} |