githubmirror/libgcrypt

src/mpi.h
347 строк14 KB
NIIBE Yutaka
mpi: Introduce mpi_tfr and use it for point_tfr.
19 ноя 2025, 04:53
19 ноя 2025, 04:53172968f
/* mpi.h  -  Multi Precision Integers
 * Copyright (C) 1994, 1996, 1998,
 *               2001, 2002, 2003, 2005 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, see <https://www.gnu.org/licenses/>.
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 * 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.
 */

#ifndef G10_MPI_H
#define G10_MPI_H

#include <config.h>
#include <stdio.h>
#include <string.h>

#include "types.h"
#include "../mpi/mpi-asm-defs.h"

#include "g10lib.h"

#ifndef _GCRYPT_IN_LIBGCRYPT
#error this file should only be used inside libgcrypt
#endif

#ifndef BITS_PER_MPI_LIMB
#if BYTES_PER_MPI_LIMB == SIZEOF_UNSIGNED_INT
  typedef unsigned int mpi_limb_t;
  typedef   signed int mpi_limb_signed_t;
#elif BYTES_PER_MPI_LIMB == SIZEOF_UNSIGNED_LONG
  typedef unsigned long int mpi_limb_t;
  typedef   signed long int mpi_limb_signed_t;
#elif BYTES_PER_MPI_LIMB == SIZEOF_UNSIGNED_LONG_LONG
  typedef unsigned long long int mpi_limb_t;
  typedef   signed long long int mpi_limb_signed_t;
#elif BYTES_PER_MPI_LIMB == SIZEOF_UNSIGNED_SHORT
  typedef unsigned short int mpi_limb_t;
  typedef   signed short int mpi_limb_signed_t;
#else
#error BYTES_PER_MPI_LIMB does not match any C type
#endif
#define BITS_PER_MPI_LIMB    (8*BYTES_PER_MPI_LIMB)
#endif /*BITS_PER_MPI_LIMB*/

#define DBG_MPI     _gcry_get_debug_flag( 2 );

struct gcry_mpi
{
  int alloced;         /* Array size (# of allocated limbs). */
  int nlimbs;          /* Number of valid limbs. */
  int sign;	       /* Indicates a negative number and is also used
		          for opaque MPIs to store the length.  */
  unsigned int flags; /* Bit 0: Array to be allocated in secure memory space.*/
                      /* Bit 2: The limb is a pointer to some m_alloced data.*/
                      /* Bit 4: Immutable MPI - the MPI may not be modified.  */
                      /* Bit 5: Constant MPI - the MPI will not be freed.  */
  mpi_limb_t *d;      /* Array with the limbs */
};

#define MPI_NULL NULL

#define mpi_get_nlimbs(a)     ((a)->nlimbs)
#define mpi_has_sign(a)	      ((a)->sign)

typedef mpi_limb_t *mpi_ptr_t; /* pointer to a limb */
typedef int mpi_size_t;        /* (must be a signed type) */

/*-- mpiutil.c --*/

#ifdef M_DEBUG
# define mpi_alloc(n)	_gcry_mpi_debug_alloc((n), M_DBGINFO( __LINE__ ) )
# define mpi_alloc_secure(n)  _gcry_mpi_debug_alloc_secure((n), M_DBGINFO( __LINE__ ) )
# define mpi_free(a)	_gcry_mpi_debug_free((a), M_DBGINFO(__LINE__) )
# define mpi_resize(a,b) _gcry_mpi_debug_resize((a),(b), M_DBGINFO(__LINE__) )
# define mpi_copy(a)	  _gcry_mpi_debug_copy((a), M_DBGINFO(__LINE__) )
  gcry_mpi_t _gcry_mpi_debug_alloc( unsigned nlimbs, const char *info );
  gcry_mpi_t _gcry_mpi_debug_alloc_secure( unsigned nlimbs, const char *info );
  void _gcry_mpi_debug_free( gcry_mpi_t a, const char *info );
  void _gcry_mpi_debug_resize( gcry_mpi_t a, unsigned nlimbs, const char *info );
  gcry_mpi_t  _gcry_mpi_debug_copy( gcry_mpi_t a, const char *info	);
#else
# define mpi_alloc(n)	       _gcry_mpi_alloc((n) )
# define mpi_alloc_secure(n)  _gcry_mpi_alloc_secure((n) )
# define mpi_free(a)	       _gcry_mpi_free((a) )
# define mpi_resize(a,b)      _gcry_mpi_resize((a),(b))
# define mpi_copy(a)	       _gcry_mpi_copy((a))
  gcry_mpi_t  _gcry_mpi_alloc( unsigned nlimbs );
  gcry_mpi_t  _gcry_mpi_alloc_secure( unsigned nlimbs );
  void _gcry_mpi_free( gcry_mpi_t a );
  void _gcry_mpi_resize( gcry_mpi_t a, unsigned nlimbs );
  gcry_mpi_t  _gcry_mpi_copy( gcry_mpi_t a );
#endif

void _gcry_mpi_immutable_failed (void);
#define mpi_immutable_failed() _gcry_mpi_immutable_failed ()

#define mpi_is_const(a)       ((a)->flags&32)
#define mpi_is_immutable(a)   ((a)->flags&16)
#define mpi_is_opaque(a)      ((a) && ((a)->flags&4))
#define mpi_is_secure(a)      ((a) && ((a)->flags&1))
#define mpi_clear(a)          _gcry_mpi_clear ((a))
#define mpi_alloc_like(a)     _gcry_mpi_alloc_like((a))

#define mpi_alloc_set_ui(a)   _gcry_mpi_alloc_set_ui ((a))
#define mpi_const(n)          _gcry_mpi_const ((n))
#define mpi_swap_cond(a,b,sw)  _gcry_mpi_swap_cond ((a),(b),(sw))
#define mpi_tfr(a,b,dir)       _gcry_mpi_tfr ((a),(b),(dir))
#define mpi_set_cond(w,u,set)  _gcry_mpi_set_cond ((w),(u),(set))
#define mpi_set_bit_cond(a,n,set) _gcry_mpi_set_bit_cond ((a),(n),(set))

void _gcry_mpi_clear( gcry_mpi_t a );
gcry_mpi_t _gcry_mpi_set_cond (gcry_mpi_t w, const gcry_mpi_t u,
                               unsigned long swap);
gcry_mpi_t  _gcry_mpi_alloc_like( gcry_mpi_t a );
gcry_mpi_t  _gcry_mpi_alloc_set_ui( unsigned long u);
void _gcry_mpi_swap( gcry_mpi_t a, gcry_mpi_t b);
void _gcry_mpi_swap_cond (gcry_mpi_t a, gcry_mpi_t b, unsigned long swap);
void _gcry_mpi_tfr (gcry_mpi_t a, gcry_mpi_t b, unsigned long dir);
void _gcry_mpi_set_bit_cond (gcry_mpi_t a, unsigned int n, unsigned long set);
gcry_mpi_t _gcry_mpi_new (unsigned int nbits);
gcry_mpi_t _gcry_mpi_snew (unsigned int nbits);
gcry_mpi_t _gcry_mpi_set_opaque_copy (gcry_mpi_t a,
                                      const void *p, unsigned int nbits);
void *_gcry_mpi_get_opaque_copy (gcry_mpi_t a, unsigned int *nbits);
int _gcry_mpi_is_neg (gcry_mpi_t a);
void _gcry_mpi_neg (gcry_mpi_t w, gcry_mpi_t u);
void _gcry_mpi_abs (gcry_mpi_t w);

/* Constants used to return constant MPIs.  See _gcry_mpi_init if you
   want to add more constants. */
#define MPI_NUMBER_OF_CONSTANTS 6
enum gcry_mpi_constants
  {
    MPI_C_ZERO,
    MPI_C_ONE,
    MPI_C_TWO,
    MPI_C_THREE,
    MPI_C_FOUR,
    MPI_C_EIGHT
  };


gcry_mpi_t _gcry_mpi_const (enum gcry_mpi_constants no);


/*-- mpicoder.c --*/
void  _gcry_log_mpidump( const char *text, gcry_mpi_t a );
u32   _gcry_mpi_get_keyid( gcry_mpi_t a, u32 *keyid );
byte *_gcry_mpi_get_buffer (gcry_mpi_t a, unsigned int fill_le,
                            unsigned int *r_nbytes, int *sign);
byte *_gcry_mpi_get_buffer_extra (gcry_mpi_t a, unsigned int fill_le,
                                  int extraalloc,
                                  unsigned int *r_nbytes, int *sign);
byte *_gcry_mpi_get_secure_buffer (gcry_mpi_t a, unsigned int fill_le,
                                   unsigned *r_nbytes, int *sign);
void  _gcry_mpi_set_buffer ( gcry_mpi_t a, const void *buffer,
                             unsigned int nbytes, int sign );
gpg_err_code_t _gcry_mpi_to_octet_string (unsigned char **r_frame,
                                          void *space,
                                          gcry_mpi_t value, size_t nbytes);

/*-- mpi-div.c --*/
#define mpi_fdiv_r_ui(a,b,c)   _gcry_mpi_fdiv_r_ui((a),(b),(c))
#define mpi_fdiv_r(a,b,c)      _gcry_mpi_fdiv_r((a),(b),(c))
#define mpi_fdiv_q(a,b,c)      _gcry_mpi_fdiv_q((a),(b),(c))
#define mpi_fdiv_qr(a,b,c,d)   _gcry_mpi_fdiv_qr((a),(b),(c),(d))
#define mpi_tdiv_r(a,b,c)      _gcry_mpi_tdiv_r((a),(b),(c))
#define mpi_tdiv_qr(a,b,c,d)   _gcry_mpi_tdiv_qr((a),(b),(c),(d))
#define mpi_tdiv_q_2exp(a,b,c) _gcry_mpi_tdiv_q_2exp((a),(b),(c))
#define mpi_divisible_ui(a,b)  _gcry_mpi_divisible_ui((a),(b))

unsigned long _gcry_mpi_fdiv_r_ui( gcry_mpi_t rem, gcry_mpi_t dividend, unsigned long divisor );
void  _gcry_mpi_fdiv_r( gcry_mpi_t rem, gcry_mpi_t dividend, gcry_mpi_t divisor );
void  _gcry_mpi_fdiv_q( gcry_mpi_t quot, gcry_mpi_t dividend, gcry_mpi_t divisor );
void  _gcry_mpi_fdiv_qr( gcry_mpi_t quot, gcry_mpi_t rem, gcry_mpi_t dividend, gcry_mpi_t divisor );
void  _gcry_mpi_tdiv_r( gcry_mpi_t rem, gcry_mpi_t num, gcry_mpi_t den);
void  _gcry_mpi_tdiv_qr( gcry_mpi_t quot, gcry_mpi_t rem, gcry_mpi_t num, gcry_mpi_t den);
void  _gcry_mpi_tdiv_q_2exp( gcry_mpi_t w, gcry_mpi_t u, unsigned count );
int   _gcry_mpi_divisible_ui(gcry_mpi_t dividend, unsigned long divisor );


/*-- mpi-mod.c --*/
#define mpi_barrett_init(m,f)     _gcry_mpi_barrett_init ((m),(f))
#define mpi_barrett_free(c)       _gcry_mpi_barrett_free ((c))
#define mpi_mod_barrett(r,a,c)    _gcry_mpi_mod_barrett ((r), (a), (c))
#define mpi_mul_barrett(r,u,v,c)  _gcry_mpi_mul_barrett ((r), (u), (v), (c))

/* Context used with Barrett reduction.  */
struct barrett_ctx_s;
typedef struct barrett_ctx_s *mpi_barrett_t;

mpi_barrett_t _gcry_mpi_barrett_init (gcry_mpi_t m, int copy);
void _gcry_mpi_barrett_free (mpi_barrett_t ctx);
void _gcry_mpi_mod_barrett (gcry_mpi_t r, gcry_mpi_t x, mpi_barrett_t ctx);
void _gcry_mpi_mul_barrett (gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v,
                            mpi_barrett_t ctx);


/*-- mpi-mpow.c --*/
#define mpi_mulpowm(a,b,c,d) _gcry_mpi_mulpowm ((a),(b),(c),(d))
void _gcry_mpi_mulpowm( gcry_mpi_t res, gcry_mpi_t *basearray, gcry_mpi_t *exparray, gcry_mpi_t mod);

/*-- mpi-scan.c --*/
#define mpi_trailing_zeros(a) _gcry_mpi_trailing_zeros ((a))
int      _gcry_mpi_getbyte( gcry_mpi_t a, unsigned idx );
void     _gcry_mpi_putbyte( gcry_mpi_t a, unsigned idx, int value );
unsigned _gcry_mpi_trailing_zeros( gcry_mpi_t a );

/*-- mpi-bit.c --*/
#define mpi_normalize(a)       _gcry_mpi_normalize ((a))

void _gcry_mpi_normalize( gcry_mpi_t a );

/*-- ec.c --*/

/* Object to represent a point in projective coordinates. */
struct gcry_mpi_point
{
  gcry_mpi_t x;
  gcry_mpi_t y;
  gcry_mpi_t z;
};
typedef struct gcry_mpi_point mpi_point_struct;
typedef struct gcry_mpi_point *mpi_point_t;

void _gcry_mpi_point_init (mpi_point_t p);
void _gcry_mpi_point_free_parts (mpi_point_t p);
void _gcry_mpi_get_point (gcry_mpi_t x, gcry_mpi_t y, gcry_mpi_t z,
                          mpi_point_t point);
void _gcry_mpi_snatch_point (gcry_mpi_t x, gcry_mpi_t y, gcry_mpi_t z,
                             mpi_point_t point);


/* Models describing an elliptic curve.  */
enum gcry_mpi_ec_models
  {
    /* The Short Weierstrass equation is
          y^2 = x^3 + ax + b
     */
    MPI_EC_WEIERSTRASS = 0,
    /* The Montgomery equation is
          by^2 = x^3 + ax^2 + x
     */
    MPI_EC_MONTGOMERY,
    /* The Twisted Edwards equation is
          ax^2 + y^2 = 1 + bx^2y^2
       Note that we use 'b' instead of the commonly used 'd'.  */
    MPI_EC_EDWARDS
  };

/* Dialects used with elliptic curves.  It is easier to keep the
   definition here than in ecc-common.h. */
enum ecc_dialects
  {
    ECC_DIALECT_STANDARD = 0,
    ECC_DIALECT_ED25519,
    ECC_DIALECT_SAFECURVE
  };


void _gcry_mpi_point_log (const char *name, mpi_point_t point, mpi_ec_t ctx);
#define log_printpnt(a,p,c) _gcry_mpi_point_log ((a), (p), (c))

mpi_ec_t _gcry_mpi_ec_p_internal_new (enum gcry_mpi_ec_models model,
                                      enum ecc_dialects dialect,
                                      int flags,
                                      gcry_mpi_t p, gcry_mpi_t a, gcry_mpi_t b);
gpg_err_code_t _gcry_mpi_ec_p_new (gcry_ctx_t *r_ctx,
                                   enum gcry_mpi_ec_models model,
                                   enum ecc_dialects dialect,
                                   int flags,
                                   gcry_mpi_t p, gcry_mpi_t a, gcry_mpi_t b);
void _gcry_mpi_ec_free (mpi_ec_t ctx);

void _gcry_mpi_ec_dup_point (mpi_point_t result,
                             mpi_point_t point, mpi_ec_t ctx);
void _gcry_mpi_ec_add_points (mpi_point_t result,
                              mpi_point_t p1, mpi_point_t p2,
                              mpi_ec_t ctx);
void _gcry_mpi_ec_sub_points (mpi_point_t result,
                              mpi_point_t p1, mpi_point_t p2,
                              mpi_ec_t ctx);
void _gcry_mpi_ec_mul_point (mpi_point_t result,
                             gcry_mpi_t scalar, mpi_point_t point,
                             mpi_ec_t ctx);
int  _gcry_mpi_ec_curve_point (gcry_mpi_point_t point, mpi_ec_t ctx);
int _gcry_mpi_ec_bad_point (gcry_mpi_point_t point, mpi_ec_t ctx);

gcry_mpi_t _gcry_mpi_ec_ec2os (gcry_mpi_point_t point, mpi_ec_t ectx);

gcry_mpi_t _gcry_mpi_ec_get_mpi (const char *name, gcry_ctx_t ctx, int copy);
gcry_mpi_point_t _gcry_mpi_ec_get_point (const char *name,
                                         gcry_ctx_t ctx, int copy);
gpg_err_code_t _gcry_mpi_ec_set_mpi (const char *name, gcry_mpi_t newvalue,
                                     gcry_ctx_t ctx);
gpg_err_code_t _gcry_mpi_ec_set_point (const char *name,
                                       gcry_mpi_point_t newvalue,
                                       gcry_ctx_t ctx);
gpg_err_code_t _gcry_mpi_ec_decode_point (mpi_point_t result,
                                          gcry_mpi_t value, mpi_ec_t ec);

/*-- ecc-curves.c --*/
gpg_err_code_t _gcry_mpi_ec_new (gcry_ctx_t *r_ctx,
                                 gcry_sexp_t keyparam, const char *curvename);
gpg_err_code_t _gcry_mpi_ec_internal_new (mpi_ec_t *r_ec, int *r_flags,
                                          const char *name_op,
                                          gcry_sexp_t keyparam,
                                          const char *curvename);

/*-- mpih-shift.c --*/
mpi_limb_t _gcry_mpih_rshift (mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize,
                              unsigned cnt);

/*-- mpih-const-time.c --*/
mpi_limb_t _gcry_mpih_add_n_cond (mpi_ptr_t wp, mpi_ptr_t up, mpi_ptr_t vp,
                                  mpi_size_t usize, unsigned long op_enable);
int _gcry_mpih_cmp_ui (mpi_ptr_t up, mpi_size_t usize, unsigned long v);
int _gcry_mpih_cmp_lli (mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size);

/*-- mpih-add.c --*/
mpi_limb_t _gcry_mpih_add_n (mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
                             mpi_ptr_t s2_ptr,  mpi_size_t size);

/* Do same calculation as _gcry_mpih_add does (under the condition
   of RES_PTR == S1_PTR and the size is same), Least Leak Intended.  */
#define _gcry_mpih_add_lli _gcry_mpih_add_n


#endif /*G10_MPI_H*/