1/* SPDX-License-Identifier: GPL-2.0-or-later */ 2/* mpi.h - Multi Precision Integers 3 * Copyright (C) 1994, 1996, 1998, 1999, 4 * 2000, 2001 Free Software Foundation, Inc. 5 * 6 * This file is part of GNUPG. 7 * 8 * Note: This code is heavily based on the GNU MP Library. 9 * Actually it's the same code with only minor changes in the 10 * way the data is stored; this is to support the abstraction 11 * of an optional secure memory allocation which may be used 12 * to avoid revealing of sensitive data due to paging etc. 13 * The GNU MP Library itself is published under the LGPL; 14 * however I decided to publish this code under the plain GPL. 15 */ 16 17#ifndef G10_MPI_H 18#define G10_MPI_H 19 20#include <linux/types.h> 21#include <linux/scatterlist.h> 22 23#define BYTES_PER_MPI_LIMB (BITS_PER_LONG / 8) 24#define BITS_PER_MPI_LIMB BITS_PER_LONG 25 26typedef unsigned long int mpi_limb_t; 27typedef signed long int mpi_limb_signed_t; 28 29struct gcry_mpi { 30 int alloced; /* array size (# of allocated limbs) */ 31 int nlimbs; /* number of valid limbs */ 32 int nbits; /* the real number of valid bits (info only) */ 33 int sign; /* indicates a negative number */ 34 unsigned flags; /* bit 0: array must be allocated in secure memory space */ 35 /* bit 1: not used */ 36 /* bit 2: the limb is a pointer to some m_alloced data */ 37 mpi_limb_t *d; /* array with the limbs */ 38}; 39 40typedef struct gcry_mpi *MPI; 41 42#define mpi_get_nlimbs(a) ((a)->nlimbs) 43#define mpi_has_sign(a) ((a)->sign) 44 45/*-- mpiutil.c --*/ 46MPI mpi_alloc(unsigned nlimbs); 47void mpi_clear(MPI a); 48void mpi_free(MPI a); 49int mpi_resize(MPI a, unsigned nlimbs); 50 51static inline MPI mpi_new(unsigned int nbits) 52{ 53 return mpi_alloc((nbits + BITS_PER_MPI_LIMB - 1) / BITS_PER_MPI_LIMB); 54} 55 56MPI mpi_copy(MPI a); 57MPI mpi_alloc_like(MPI a); 58void mpi_snatch(MPI w, MPI u); 59MPI mpi_set(MPI w, MPI u); 60MPI mpi_set_ui(MPI w, unsigned long u); 61MPI mpi_alloc_set_ui(unsigned long u); 62void mpi_swap_cond(MPI a, MPI b, unsigned long swap); 63 64/* Constants used to return constant MPIs. See mpi_init if you 65 * want to add more constants. 66 */ 67#define MPI_NUMBER_OF_CONSTANTS 6 68enum gcry_mpi_constants { 69 MPI_C_ZERO, 70 MPI_C_ONE, 71 MPI_C_TWO, 72 MPI_C_THREE, 73 MPI_C_FOUR, 74 MPI_C_EIGHT 75}; 76 77MPI mpi_const(enum gcry_mpi_constants no); 78 79/*-- mpicoder.c --*/ 80 81/* Different formats of external big integer representation. */ 82enum gcry_mpi_format { 83 GCRYMPI_FMT_NONE = 0, 84 GCRYMPI_FMT_STD = 1, /* Twos complement stored without length. */ 85 GCRYMPI_FMT_PGP = 2, /* As used by OpenPGP (unsigned only). */ 86 GCRYMPI_FMT_SSH = 3, /* As used by SSH (like STD but with length). */ 87 GCRYMPI_FMT_HEX = 4, /* Hex format. */ 88 GCRYMPI_FMT_USG = 5, /* Like STD but unsigned. */ 89 GCRYMPI_FMT_OPAQUE = 8 /* Opaque format (some functions only). */ 90}; 91 92MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes); 93MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread); 94int mpi_fromstr(MPI val, const char *str); 95MPI mpi_scanval(const char *string); 96MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len); 97void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign); 98int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes, 99 int *sign); 100int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes, 101 int *sign); 102int mpi_print(enum gcry_mpi_format format, unsigned char *buffer, 103 size_t buflen, size_t *nwritten, MPI a); 104 105/*-- mpi-mod.c --*/ 106void mpi_mod(MPI rem, MPI dividend, MPI divisor); 107 108/* Context used with Barrett reduction. */ 109struct barrett_ctx_s; 110typedef struct barrett_ctx_s *mpi_barrett_t; 111 112mpi_barrett_t mpi_barrett_init(MPI m, int copy); 113void mpi_barrett_free(mpi_barrett_t ctx); 114void mpi_mod_barrett(MPI r, MPI x, mpi_barrett_t ctx); 115void mpi_mul_barrett(MPI w, MPI u, MPI v, mpi_barrett_t ctx); 116 117/*-- mpi-pow.c --*/ 118int mpi_powm(MPI res, MPI base, MPI exp, MPI mod); 119 120/*-- mpi-cmp.c --*/ 121int mpi_cmp_ui(MPI u, ulong v); 122int mpi_cmp(MPI u, MPI v); 123int mpi_cmpabs(MPI u, MPI v); 124 125/*-- mpi-sub-ui.c --*/ 126int mpi_sub_ui(MPI w, MPI u, unsigned long vval); 127 128/*-- mpi-bit.c --*/ 129void mpi_normalize(MPI a); 130unsigned mpi_get_nbits(MPI a); 131int mpi_test_bit(MPI a, unsigned int n); 132void mpi_set_bit(MPI a, unsigned int n); 133void mpi_set_highbit(MPI a, unsigned int n); 134void mpi_clear_highbit(MPI a, unsigned int n); 135void mpi_clear_bit(MPI a, unsigned int n); 136void mpi_rshift_limbs(MPI a, unsigned int count); 137void mpi_rshift(MPI x, MPI a, unsigned int n); 138void mpi_lshift_limbs(MPI a, unsigned int count); 139void mpi_lshift(MPI x, MPI a, unsigned int n); 140 141/*-- mpi-add.c --*/ 142void mpi_add_ui(MPI w, MPI u, unsigned long v); 143void mpi_add(MPI w, MPI u, MPI v); 144void mpi_sub(MPI w, MPI u, MPI v); 145void mpi_addm(MPI w, MPI u, MPI v, MPI m); 146void mpi_subm(MPI w, MPI u, MPI v, MPI m); 147 148/*-- mpi-mul.c --*/ 149void mpi_mul(MPI w, MPI u, MPI v); 150void mpi_mulm(MPI w, MPI u, MPI v, MPI m); 151 152/*-- mpi-div.c --*/ 153void mpi_tdiv_r(MPI rem, MPI num, MPI den); 154void mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor); 155void mpi_fdiv_q(MPI quot, MPI dividend, MPI divisor); 156 157/*-- mpi-inv.c --*/ 158int mpi_invm(MPI x, MPI a, MPI n); 159 160/*-- ec.c --*/ 161 162/* Object to represent a point in projective coordinates */ 163struct gcry_mpi_point { 164 MPI x; 165 MPI y; 166 MPI z; 167}; 168 169typedef struct gcry_mpi_point *MPI_POINT; 170 171/* Models describing an elliptic curve */ 172enum gcry_mpi_ec_models { 173 /* The Short Weierstrass equation is 174 * y^2 = x^3 + ax + b 175 */ 176 MPI_EC_WEIERSTRASS = 0, 177 /* The Montgomery equation is 178 * by^2 = x^3 + ax^2 + x 179 */ 180 MPI_EC_MONTGOMERY, 181 /* The Twisted Edwards equation is 182 * ax^2 + y^2 = 1 + bx^2y^2 183 * Note that we use 'b' instead of the commonly used 'd'. 184 */ 185 MPI_EC_EDWARDS 186}; 187 188/* Dialects used with elliptic curves */ 189enum ecc_dialects { 190 ECC_DIALECT_STANDARD = 0, 191 ECC_DIALECT_ED25519, 192 ECC_DIALECT_SAFECURVE 193}; 194 195/* This context is used with all our EC functions. */ 196struct mpi_ec_ctx { 197 enum gcry_mpi_ec_models model; /* The model describing this curve. */ 198 enum ecc_dialects dialect; /* The ECC dialect used with the curve. */ 199 int flags; /* Public key flags (not always used). */ 200 unsigned int nbits; /* Number of bits. */ 201 202 /* Domain parameters. Note that they may not all be set and if set 203 * the MPIs may be flagged as constant. 204 */ 205 MPI p; /* Prime specifying the field GF(p). */ 206 MPI a; /* First coefficient of the Weierstrass equation. */ 207 MPI b; /* Second coefficient of the Weierstrass equation. */ 208 MPI_POINT G; /* Base point (generator). */ 209 MPI n; /* Order of G. */ 210 unsigned int h; /* Cofactor. */ 211 212 /* The actual key. May not be set. */ 213 MPI_POINT Q; /* Public key. */ 214 MPI d; /* Private key. */ 215 216 const char *name; /* Name of the curve. */ 217 218 /* This structure is private to mpi/ec.c! */ 219 struct { 220 struct { 221 unsigned int a_is_pminus3:1; 222 unsigned int two_inv_p:1; 223 } valid; /* Flags to help setting the helper vars below. */ 224 225 int a_is_pminus3; /* True if A = P - 3. */ 226 227 MPI two_inv_p; 228 229 mpi_barrett_t p_barrett; 230 231 /* Scratch variables. */ 232 MPI scratch[11]; 233 234 /* Helper for fast reduction. */ 235 /* int nist_nbits; /\* If this is a NIST curve, the # of bits. *\/ */ 236 /* MPI s[10]; */ 237 /* MPI c; */ 238 } t; 239 240 /* Curve specific computation routines for the field. */ 241 void (*addm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx); 242 void (*subm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ec); 243 void (*mulm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx); 244 void (*pow2)(MPI w, const MPI b, struct mpi_ec_ctx *ctx); 245 void (*mul2)(MPI w, MPI u, struct mpi_ec_ctx *ctx); 246}; 247 248void mpi_ec_init(struct mpi_ec_ctx *ctx, enum gcry_mpi_ec_models model, 249 enum ecc_dialects dialect, 250 int flags, MPI p, MPI a, MPI b); 251void mpi_ec_deinit(struct mpi_ec_ctx *ctx); 252MPI_POINT mpi_point_new(unsigned int nbits); 253void mpi_point_release(MPI_POINT p); 254void mpi_point_init(MPI_POINT p); 255void mpi_point_free_parts(MPI_POINT p); 256int mpi_ec_get_affine(MPI x, MPI y, MPI_POINT point, struct mpi_ec_ctx *ctx); 257void mpi_ec_add_points(MPI_POINT result, 258 MPI_POINT p1, MPI_POINT p2, 259 struct mpi_ec_ctx *ctx); 260void mpi_ec_mul_point(MPI_POINT result, 261 MPI scalar, MPI_POINT point, 262 struct mpi_ec_ctx *ctx); 263int mpi_ec_curve_point(MPI_POINT point, struct mpi_ec_ctx *ctx); 264 265/* inline functions */ 266 267/** 268 * mpi_get_size() - returns max size required to store the number 269 * 270 * @a: A multi precision integer for which we want to allocate a buffer 271 * 272 * Return: size required to store the number 273 */ 274static inline unsigned int mpi_get_size(MPI a) 275{ 276 return a->nlimbs * BYTES_PER_MPI_LIMB; 277} 278#endif /*G10_MPI_H */ 279