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lib/mpi: Extend the MPI library
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Expand the mpi library based on libgcrypt, and the ECC algorithm of
mpi based on libgcrypt requires these functions.
Some other algorithms will be developed based on mpi ecc, such as SM2.

Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Tested-by: Xufeng Zhang <yunbo.xufeng@linux.alibaba.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Tianjia Zhang authored and Herbert Xu committed Sep 25, 2020
1 parent f492828 commit a8ea8bd
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Showing 14 changed files with 2,076 additions and 10 deletions.
87 changes: 87 additions & 0 deletions include/linux/mpi.h
Original file line number Diff line number Diff line change
Expand Up @@ -40,35 +40,122 @@ struct gcry_mpi {
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);

/* inline functions */

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5 changes: 5 additions & 0 deletions lib/mpi/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -14,9 +14,14 @@ mpi-y = \
generic_mpih-sub1.o \
generic_mpih-add1.o \
mpicoder.o \
mpi-add.o \
mpi-bit.o \
mpi-cmp.o \
mpi-sub-ui.o \
mpi-div.o \
mpi-inv.o \
mpi-mod.o \
mpi-mul.o \
mpih-cmp.o \
mpih-div.o \
mpih-mul.o \
Expand Down
155 changes: 155 additions & 0 deletions lib/mpi/mpi-add.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,155 @@
/* mpi-add.c - MPI functions
* Copyright (C) 1994, 1996, 1998, 2001, 2002,
* 2003 Free Software Foundation, Inc.
*
* This file is part of Libgcrypt.
*
* 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 "mpi-internal.h"

/****************
* Add the unsigned integer V to the mpi-integer U and store the
* result in W. U and V may be the same.
*/
void mpi_add_ui(MPI w, MPI u, unsigned long v)
{
mpi_ptr_t wp, up;
mpi_size_t usize, wsize;
int usign, wsign;

usize = u->nlimbs;
usign = u->sign;
wsign = 0;

/* If not space for W (and possible carry), increase space. */
wsize = usize + 1;
if (w->alloced < wsize)
mpi_resize(w, wsize);

/* These must be after realloc (U may be the same as W). */
up = u->d;
wp = w->d;

if (!usize) { /* simple */
wp[0] = v;
wsize = v ? 1:0;
} else if (!usign) { /* mpi is not negative */
mpi_limb_t cy;
cy = mpihelp_add_1(wp, up, usize, v);
wp[usize] = cy;
wsize = usize + cy;
} else {
/* The signs are different. Need exact comparison to determine
* which operand to subtract from which.
*/
if (usize == 1 && up[0] < v) {
wp[0] = v - up[0];
wsize = 1;
} else {
mpihelp_sub_1(wp, up, usize, v);
/* Size can decrease with at most one limb. */
wsize = usize - (wp[usize-1] == 0);
wsign = 1;
}
}

w->nlimbs = wsize;
w->sign = wsign;
}


void mpi_add(MPI w, MPI u, MPI v)
{
mpi_ptr_t wp, up, vp;
mpi_size_t usize, vsize, wsize;
int usign, vsign, wsign;

if (u->nlimbs < v->nlimbs) { /* Swap U and V. */
usize = v->nlimbs;
usign = v->sign;
vsize = u->nlimbs;
vsign = u->sign;
wsize = usize + 1;
RESIZE_IF_NEEDED(w, wsize);
/* These must be after realloc (u or v may be the same as w). */
up = v->d;
vp = u->d;
} else {
usize = u->nlimbs;
usign = u->sign;
vsize = v->nlimbs;
vsign = v->sign;
wsize = usize + 1;
RESIZE_IF_NEEDED(w, wsize);
/* These must be after realloc (u or v may be the same as w). */
up = u->d;
vp = v->d;
}
wp = w->d;
wsign = 0;

if (!vsize) { /* simple */
MPN_COPY(wp, up, usize);
wsize = usize;
wsign = usign;
} else if (usign != vsign) { /* different sign */
/* This test is right since USIZE >= VSIZE */
if (usize != vsize) {
mpihelp_sub(wp, up, usize, vp, vsize);
wsize = usize;
MPN_NORMALIZE(wp, wsize);
wsign = usign;
} else if (mpihelp_cmp(up, vp, usize) < 0) {
mpihelp_sub_n(wp, vp, up, usize);
wsize = usize;
MPN_NORMALIZE(wp, wsize);
if (!usign)
wsign = 1;
} else {
mpihelp_sub_n(wp, up, vp, usize);
wsize = usize;
MPN_NORMALIZE(wp, wsize);
if (usign)
wsign = 1;
}
} else { /* U and V have same sign. Add them. */
mpi_limb_t cy = mpihelp_add(wp, up, usize, vp, vsize);
wp[usize] = cy;
wsize = usize + cy;
if (usign)
wsign = 1;
}

w->nlimbs = wsize;
w->sign = wsign;
}
EXPORT_SYMBOL_GPL(mpi_add);

void mpi_sub(MPI w, MPI u, MPI v)
{
MPI vv = mpi_copy(v);
vv->sign = !vv->sign;
mpi_add(w, u, vv);
mpi_free(vv);
}


void mpi_addm(MPI w, MPI u, MPI v, MPI m)
{
mpi_add(w, u, v);
mpi_mod(w, w, m);
}
EXPORT_SYMBOL_GPL(mpi_addm);

void mpi_subm(MPI w, MPI u, MPI v, MPI m)
{
mpi_sub(w, u, v);
mpi_mod(w, w, m);
}
EXPORT_SYMBOL_GPL(mpi_subm);
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