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Diffstat (limited to 'include/linux/mpi.h')
-rw-r--r-- | include/linux/mpi.h | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/include/linux/mpi.h b/include/linux/mpi.h new file mode 100644 index 000000000..eb0d1c1db --- /dev/null +++ b/include/linux/mpi.h @@ -0,0 +1,278 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* mpi.h - Multi Precision Integers + * Copyright (C) 1994, 1996, 1998, 1999, + * 2000, 2001 Free Software Foundation, Inc. + * + * This file is part of GNUPG. + * + * 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. + * The GNU MP Library itself is published under the LGPL; + * however I decided to publish this code under the plain GPL. + */ + +#ifndef G10_MPI_H +#define G10_MPI_H + +#include <linux/types.h> +#include <linux/scatterlist.h> + +#define BYTES_PER_MPI_LIMB (BITS_PER_LONG / 8) +#define BITS_PER_MPI_LIMB BITS_PER_LONG + +typedef unsigned long int mpi_limb_t; +typedef signed long int mpi_limb_signed_t; + +struct gcry_mpi { + int alloced; /* array size (# of allocated limbs) */ + int nlimbs; /* number of valid limbs */ + int nbits; /* the real number of valid bits (info only) */ + int sign; /* indicates a negative number */ + unsigned flags; /* bit 0: array must be allocated in secure memory space */ + /* bit 1: not used */ + /* bit 2: the limb is a pointer to some m_alloced data */ + mpi_limb_t *d; /* array with the limbs */ +}; + +typedef struct gcry_mpi *MPI; + +#define mpi_get_nlimbs(a) ((a)->nlimbs) +#define mpi_has_sign(a) ((a)->sign) + +/*-- mpiutil.c --*/ +MPI mpi_alloc(unsigned nlimbs); +void mpi_clear(MPI a); +void mpi_free(MPI a); +int mpi_resize(MPI a, unsigned nlimbs); + +static inline MPI mpi_new(unsigned int nbits) +{ + return mpi_alloc((nbits + BITS_PER_MPI_LIMB - 1) / BITS_PER_MPI_LIMB); +} + +MPI mpi_copy(MPI a); +MPI mpi_alloc_like(MPI a); +void mpi_snatch(MPI w, MPI u); +MPI mpi_set(MPI w, MPI u); +MPI mpi_set_ui(MPI w, unsigned long u); +MPI mpi_alloc_set_ui(unsigned long u); +void mpi_swap_cond(MPI a, MPI b, unsigned long swap); + +/* Constants used to return constant MPIs. See 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 +}; + +MPI mpi_const(enum gcry_mpi_constants no); + +/*-- mpicoder.c --*/ + +/* Different formats of external big integer representation. */ +enum gcry_mpi_format { + GCRYMPI_FMT_NONE = 0, + GCRYMPI_FMT_STD = 1, /* Twos complement stored without length. */ + GCRYMPI_FMT_PGP = 2, /* As used by OpenPGP (unsigned only). */ + GCRYMPI_FMT_SSH = 3, /* As used by SSH (like STD but with length). */ + GCRYMPI_FMT_HEX = 4, /* Hex format. */ + GCRYMPI_FMT_USG = 5, /* Like STD but unsigned. */ + GCRYMPI_FMT_OPAQUE = 8 /* Opaque format (some functions only). */ +}; + +MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes); +MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread); +int mpi_fromstr(MPI val, const char *str); +MPI mpi_scanval(const char *string); +MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len); +void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign); +int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes, + int *sign); +int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes, + int *sign); +int mpi_print(enum gcry_mpi_format format, unsigned char *buffer, + size_t buflen, size_t *nwritten, MPI a); + +/*-- mpi-mod.c --*/ +void mpi_mod(MPI rem, MPI dividend, MPI divisor); + +/* Context used with Barrett reduction. */ +struct barrett_ctx_s; +typedef struct barrett_ctx_s *mpi_barrett_t; + +mpi_barrett_t mpi_barrett_init(MPI m, int copy); +void mpi_barrett_free(mpi_barrett_t ctx); +void mpi_mod_barrett(MPI r, MPI x, mpi_barrett_t ctx); +void mpi_mul_barrett(MPI w, MPI u, MPI v, mpi_barrett_t ctx); + +/*-- mpi-pow.c --*/ +int mpi_powm(MPI res, MPI base, MPI exp, MPI mod); + +/*-- mpi-cmp.c --*/ +int mpi_cmp_ui(MPI u, ulong v); +int mpi_cmp(MPI u, MPI v); +int mpi_cmpabs(MPI u, MPI v); + +/*-- mpi-sub-ui.c --*/ +int mpi_sub_ui(MPI w, MPI u, unsigned long vval); + +/*-- mpi-bit.c --*/ +void mpi_normalize(MPI a); +unsigned mpi_get_nbits(MPI a); +int mpi_test_bit(MPI a, unsigned int n); +void mpi_set_bit(MPI a, unsigned int n); +void mpi_set_highbit(MPI a, unsigned int n); +void mpi_clear_highbit(MPI a, unsigned int n); +void mpi_clear_bit(MPI a, unsigned int n); +void mpi_rshift_limbs(MPI a, unsigned int count); +void mpi_rshift(MPI x, MPI a, unsigned int n); +void mpi_lshift_limbs(MPI a, unsigned int count); +void mpi_lshift(MPI x, MPI a, unsigned int n); + +/*-- mpi-add.c --*/ +void mpi_add_ui(MPI w, MPI u, unsigned long v); +void mpi_add(MPI w, MPI u, MPI v); +void mpi_sub(MPI w, MPI u, MPI v); +void mpi_addm(MPI w, MPI u, MPI v, MPI m); +void mpi_subm(MPI w, MPI u, MPI v, MPI m); + +/*-- mpi-mul.c --*/ +void mpi_mul(MPI w, MPI u, MPI v); +void mpi_mulm(MPI w, MPI u, MPI v, MPI m); + +/*-- mpi-div.c --*/ +void mpi_tdiv_r(MPI rem, MPI num, MPI den); +void mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor); +void mpi_fdiv_q(MPI quot, MPI dividend, MPI divisor); + +/*-- mpi-inv.c --*/ +int mpi_invm(MPI x, MPI a, MPI n); + +/*-- ec.c --*/ + +/* Object to represent a point in projective coordinates */ +struct gcry_mpi_point { + MPI x; + MPI y; + MPI z; +}; + +typedef struct gcry_mpi_point *MPI_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 */ +enum ecc_dialects { + ECC_DIALECT_STANDARD = 0, + ECC_DIALECT_ED25519, + ECC_DIALECT_SAFECURVE +}; + +/* This context is used with all our EC functions. */ +struct mpi_ec_ctx { + enum gcry_mpi_ec_models model; /* The model describing this curve. */ + enum ecc_dialects dialect; /* The ECC dialect used with the curve. */ + int flags; /* Public key flags (not always used). */ + unsigned int nbits; /* Number of bits. */ + + /* Domain parameters. Note that they may not all be set and if set + * the MPIs may be flagged as constant. + */ + MPI p; /* Prime specifying the field GF(p). */ + MPI a; /* First coefficient of the Weierstrass equation. */ + MPI b; /* Second coefficient of the Weierstrass equation. */ + MPI_POINT G; /* Base point (generator). */ + MPI n; /* Order of G. */ + unsigned int h; /* Cofactor. */ + + /* The actual key. May not be set. */ + MPI_POINT Q; /* Public key. */ + MPI d; /* Private key. */ + + const char *name; /* Name of the curve. */ + + /* This structure is private to mpi/ec.c! */ + struct { + struct { + unsigned int a_is_pminus3:1; + unsigned int two_inv_p:1; + } valid; /* Flags to help setting the helper vars below. */ + + int a_is_pminus3; /* True if A = P - 3. */ + + MPI two_inv_p; + + mpi_barrett_t p_barrett; + + /* Scratch variables. */ + MPI scratch[11]; + + /* Helper for fast reduction. */ + /* int nist_nbits; /\* If this is a NIST curve, the # of bits. *\/ */ + /* MPI s[10]; */ + /* MPI c; */ + } t; + + /* Curve specific computation routines for the field. */ + void (*addm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx); + void (*subm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ec); + void (*mulm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx); + void (*pow2)(MPI w, const MPI b, struct mpi_ec_ctx *ctx); + void (*mul2)(MPI w, MPI u, struct mpi_ec_ctx *ctx); +}; + +void mpi_ec_init(struct mpi_ec_ctx *ctx, enum gcry_mpi_ec_models model, + enum ecc_dialects dialect, + int flags, MPI p, MPI a, MPI b); +void mpi_ec_deinit(struct mpi_ec_ctx *ctx); +MPI_POINT mpi_point_new(unsigned int nbits); +void mpi_point_release(MPI_POINT p); +void mpi_point_init(MPI_POINT p); +void mpi_point_free_parts(MPI_POINT p); +int mpi_ec_get_affine(MPI x, MPI y, MPI_POINT point, struct mpi_ec_ctx *ctx); +void mpi_ec_add_points(MPI_POINT result, + MPI_POINT p1, MPI_POINT p2, + struct mpi_ec_ctx *ctx); +void mpi_ec_mul_point(MPI_POINT result, + MPI scalar, MPI_POINT point, + struct mpi_ec_ctx *ctx); +int mpi_ec_curve_point(MPI_POINT point, struct mpi_ec_ctx *ctx); + +/* inline functions */ + +/** + * mpi_get_size() - returns max size required to store the number + * + * @a: A multi precision integer for which we want to allocate a buffer + * + * Return: size required to store the number + */ +static inline unsigned int mpi_get_size(MPI a) +{ + return a->nlimbs * BYTES_PER_MPI_LIMB; +} +#endif /*G10_MPI_H */ |