279 lines
8.4 KiB
C
279 lines
8.4 KiB
C
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/* SPDX-License-Identifier: GPL-2.0-or-later */
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/* mpi.h - Multi Precision Integers
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* Copyright (C) 1994, 1996, 1998, 1999,
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* 2000, 2001 Free Software Foundation, Inc.
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*
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* This file is part of GNUPG.
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*
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* Note: This code is heavily based on the GNU MP Library.
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* Actually it's the same code with only minor changes in the
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* way the data is stored; this is to support the abstraction
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* of an optional secure memory allocation which may be used
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* to avoid revealing of sensitive data due to paging etc.
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* The GNU MP Library itself is published under the LGPL;
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* however I decided to publish this code under the plain GPL.
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*/
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#ifndef G10_MPI_H
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#define G10_MPI_H
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#include <linux/types.h>
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#include <linux/scatterlist.h>
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#define BYTES_PER_MPI_LIMB (BITS_PER_LONG / 8)
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#define BITS_PER_MPI_LIMB BITS_PER_LONG
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typedef unsigned long int mpi_limb_t;
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typedef signed long int mpi_limb_signed_t;
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struct gcry_mpi {
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int alloced; /* array size (# of allocated limbs) */
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int nlimbs; /* number of valid limbs */
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int nbits; /* the real number of valid bits (info only) */
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int sign; /* indicates a negative number */
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unsigned flags; /* bit 0: array must be allocated in secure memory space */
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/* bit 1: not used */
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/* bit 2: the limb is a pointer to some m_alloced data */
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mpi_limb_t *d; /* array with the limbs */
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};
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typedef struct gcry_mpi *MPI;
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#define mpi_get_nlimbs(a) ((a)->nlimbs)
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#define mpi_has_sign(a) ((a)->sign)
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/*-- mpiutil.c --*/
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MPI mpi_alloc(unsigned nlimbs);
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void mpi_clear(MPI a);
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void mpi_free(MPI a);
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int mpi_resize(MPI a, unsigned nlimbs);
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static inline MPI mpi_new(unsigned int nbits)
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{
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return mpi_alloc((nbits + BITS_PER_MPI_LIMB - 1) / BITS_PER_MPI_LIMB);
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}
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MPI mpi_copy(MPI a);
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MPI mpi_alloc_like(MPI a);
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void mpi_snatch(MPI w, MPI u);
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MPI mpi_set(MPI w, MPI u);
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MPI mpi_set_ui(MPI w, unsigned long u);
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MPI mpi_alloc_set_ui(unsigned long u);
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void mpi_swap_cond(MPI a, MPI b, unsigned long swap);
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/* Constants used to return constant MPIs. See mpi_init if you
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* want to add more constants.
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*/
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#define MPI_NUMBER_OF_CONSTANTS 6
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enum gcry_mpi_constants {
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MPI_C_ZERO,
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MPI_C_ONE,
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MPI_C_TWO,
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MPI_C_THREE,
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MPI_C_FOUR,
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MPI_C_EIGHT
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};
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MPI mpi_const(enum gcry_mpi_constants no);
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/*-- mpicoder.c --*/
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/* Different formats of external big integer representation. */
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enum gcry_mpi_format {
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GCRYMPI_FMT_NONE = 0,
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GCRYMPI_FMT_STD = 1, /* Twos complement stored without length. */
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GCRYMPI_FMT_PGP = 2, /* As used by OpenPGP (unsigned only). */
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GCRYMPI_FMT_SSH = 3, /* As used by SSH (like STD but with length). */
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GCRYMPI_FMT_HEX = 4, /* Hex format. */
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GCRYMPI_FMT_USG = 5, /* Like STD but unsigned. */
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GCRYMPI_FMT_OPAQUE = 8 /* Opaque format (some functions only). */
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};
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MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes);
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MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread);
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int mpi_fromstr(MPI val, const char *str);
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MPI mpi_scanval(const char *string);
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MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len);
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void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign);
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int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
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int *sign);
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int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes,
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int *sign);
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int mpi_print(enum gcry_mpi_format format, unsigned char *buffer,
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size_t buflen, size_t *nwritten, MPI a);
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/*-- mpi-mod.c --*/
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void mpi_mod(MPI rem, MPI dividend, MPI divisor);
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/* Context used with Barrett reduction. */
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struct barrett_ctx_s;
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typedef struct barrett_ctx_s *mpi_barrett_t;
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mpi_barrett_t mpi_barrett_init(MPI m, int copy);
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void mpi_barrett_free(mpi_barrett_t ctx);
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void mpi_mod_barrett(MPI r, MPI x, mpi_barrett_t ctx);
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void mpi_mul_barrett(MPI w, MPI u, MPI v, mpi_barrett_t ctx);
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/*-- mpi-pow.c --*/
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int mpi_powm(MPI res, MPI base, MPI exp, MPI mod);
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/*-- mpi-cmp.c --*/
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int mpi_cmp_ui(MPI u, ulong v);
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int mpi_cmp(MPI u, MPI v);
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int mpi_cmpabs(MPI u, MPI v);
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/*-- mpi-sub-ui.c --*/
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int mpi_sub_ui(MPI w, MPI u, unsigned long vval);
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/*-- mpi-bit.c --*/
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void mpi_normalize(MPI a);
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unsigned mpi_get_nbits(MPI a);
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int mpi_test_bit(MPI a, unsigned int n);
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void mpi_set_bit(MPI a, unsigned int n);
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void mpi_set_highbit(MPI a, unsigned int n);
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void mpi_clear_highbit(MPI a, unsigned int n);
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void mpi_clear_bit(MPI a, unsigned int n);
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void mpi_rshift_limbs(MPI a, unsigned int count);
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void mpi_rshift(MPI x, MPI a, unsigned int n);
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void mpi_lshift_limbs(MPI a, unsigned int count);
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void mpi_lshift(MPI x, MPI a, unsigned int n);
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/*-- mpi-add.c --*/
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void mpi_add_ui(MPI w, MPI u, unsigned long v);
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void mpi_add(MPI w, MPI u, MPI v);
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void mpi_sub(MPI w, MPI u, MPI v);
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void mpi_addm(MPI w, MPI u, MPI v, MPI m);
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void mpi_subm(MPI w, MPI u, MPI v, MPI m);
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/*-- mpi-mul.c --*/
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void mpi_mul(MPI w, MPI u, MPI v);
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void mpi_mulm(MPI w, MPI u, MPI v, MPI m);
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/*-- mpi-div.c --*/
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void mpi_tdiv_r(MPI rem, MPI num, MPI den);
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void mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor);
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void mpi_fdiv_q(MPI quot, MPI dividend, MPI divisor);
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/*-- mpi-inv.c --*/
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int mpi_invm(MPI x, MPI a, MPI n);
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/*-- ec.c --*/
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/* Object to represent a point in projective coordinates */
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struct gcry_mpi_point {
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MPI x;
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MPI y;
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MPI z;
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};
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typedef struct gcry_mpi_point *MPI_POINT;
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/* Models describing an elliptic curve */
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enum gcry_mpi_ec_models {
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/* The Short Weierstrass equation is
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* y^2 = x^3 + ax + b
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*/
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MPI_EC_WEIERSTRASS = 0,
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/* The Montgomery equation is
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* by^2 = x^3 + ax^2 + x
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*/
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MPI_EC_MONTGOMERY,
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/* The Twisted Edwards equation is
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* ax^2 + y^2 = 1 + bx^2y^2
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* Note that we use 'b' instead of the commonly used 'd'.
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*/
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MPI_EC_EDWARDS
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};
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/* Dialects used with elliptic curves */
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enum ecc_dialects {
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ECC_DIALECT_STANDARD = 0,
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ECC_DIALECT_ED25519,
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ECC_DIALECT_SAFECURVE
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};
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/* This context is used with all our EC functions. */
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struct mpi_ec_ctx {
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enum gcry_mpi_ec_models model; /* The model describing this curve. */
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enum ecc_dialects dialect; /* The ECC dialect used with the curve. */
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int flags; /* Public key flags (not always used). */
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unsigned int nbits; /* Number of bits. */
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/* Domain parameters. Note that they may not all be set and if set
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* the MPIs may be flagged as constant.
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*/
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MPI p; /* Prime specifying the field GF(p). */
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MPI a; /* First coefficient of the Weierstrass equation. */
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MPI b; /* Second coefficient of the Weierstrass equation. */
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MPI_POINT G; /* Base point (generator). */
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MPI n; /* Order of G. */
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unsigned int h; /* Cofactor. */
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/* The actual key. May not be set. */
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MPI_POINT Q; /* Public key. */
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MPI d; /* Private key. */
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const char *name; /* Name of the curve. */
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/* This structure is private to mpi/ec.c! */
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struct {
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struct {
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unsigned int a_is_pminus3:1;
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unsigned int two_inv_p:1;
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} valid; /* Flags to help setting the helper vars below. */
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int a_is_pminus3; /* True if A = P - 3. */
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MPI two_inv_p;
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mpi_barrett_t p_barrett;
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/* Scratch variables. */
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MPI scratch[11];
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/* Helper for fast reduction. */
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/* int nist_nbits; /\* If this is a NIST curve, the # of bits. *\/ */
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/* MPI s[10]; */
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/* MPI c; */
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} t;
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/* Curve specific computation routines for the field. */
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void (*addm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx);
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void (*subm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ec);
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void (*mulm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx);
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void (*pow2)(MPI w, const MPI b, struct mpi_ec_ctx *ctx);
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void (*mul2)(MPI w, MPI u, struct mpi_ec_ctx *ctx);
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};
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void mpi_ec_init(struct mpi_ec_ctx *ctx, enum gcry_mpi_ec_models model,
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enum ecc_dialects dialect,
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int flags, MPI p, MPI a, MPI b);
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void mpi_ec_deinit(struct mpi_ec_ctx *ctx);
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MPI_POINT mpi_point_new(unsigned int nbits);
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void mpi_point_release(MPI_POINT p);
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void mpi_point_init(MPI_POINT p);
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void mpi_point_free_parts(MPI_POINT p);
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int mpi_ec_get_affine(MPI x, MPI y, MPI_POINT point, struct mpi_ec_ctx *ctx);
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void mpi_ec_add_points(MPI_POINT result,
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MPI_POINT p1, MPI_POINT p2,
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struct mpi_ec_ctx *ctx);
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void mpi_ec_mul_point(MPI_POINT result,
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MPI scalar, MPI_POINT point,
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struct mpi_ec_ctx *ctx);
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int mpi_ec_curve_point(MPI_POINT point, struct mpi_ec_ctx *ctx);
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/* inline functions */
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/**
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* mpi_get_size() - returns max size required to store the number
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*
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* @a: A multi precision integer for which we want to allocate a buffer
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*
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* Return: size required to store the number
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*/
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static inline unsigned int mpi_get_size(MPI a)
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{
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return a->nlimbs * BYTES_PER_MPI_LIMB;
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}
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#endif /*G10_MPI_H */
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