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
26 typedef unsigned long int mpi_limb_t;
27 typedef signed long int mpi_limb_signed_t;
28
29 struct 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
40 typedef struct gcry_mpi *MPI;
41
42 #define mpi_get_nlimbs(a) ((a)->nlimbs)
43
44 /*-- mpiutil.c --*/
45 MPI mpi_alloc(unsigned nlimbs);
46 void mpi_free(MPI a);
47 int mpi_resize(MPI a, unsigned nlimbs);
48
49 MPI mpi_copy(MPI a);
50
51 /*-- mpicoder.c --*/
52 MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes);
53 MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread);
54 MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len);
55 void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign);
56 int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
57 int *sign);
58 int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes,
59 int *sign);
60
61 /*-- mpi-mod.c --*/
62 int mpi_mod(MPI rem, MPI dividend, MPI divisor);
63
64 /*-- mpi-pow.c --*/
65 int mpi_powm(MPI res, MPI base, MPI exp, MPI mod);
66
67 /*-- mpi-cmp.c --*/
68 int mpi_cmp_ui(MPI u, ulong v);
69 int mpi_cmp(MPI u, MPI v);
70
71 /*-- mpi-sub-ui.c --*/
72 int mpi_sub_ui(MPI w, MPI u, unsigned long vval);
73
74 /*-- mpi-bit.c --*/
75 void mpi_normalize(MPI a);
76 unsigned mpi_get_nbits(MPI a);
77 int mpi_test_bit(MPI a, unsigned int n);
78 int mpi_set_bit(MPI a, unsigned int n);
79 int mpi_rshift(MPI x, MPI a, unsigned int n);
80
81 /*-- mpi-add.c --*/
82 int mpi_add(MPI w, MPI u, MPI v);
83 int mpi_sub(MPI w, MPI u, MPI v);
84 int mpi_addm(MPI w, MPI u, MPI v, MPI m);
85 int mpi_subm(MPI w, MPI u, MPI v, MPI m);
86
87 /*-- mpi-mul.c --*/
88 int mpi_mul(MPI w, MPI u, MPI v);
89 int mpi_mulm(MPI w, MPI u, MPI v, MPI m);
90
91 /*-- mpi-div.c --*/
92 int mpi_tdiv_r(MPI rem, MPI num, MPI den);
93 int mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor);
94
95 /* inline functions */
96
97 /**
98 * mpi_get_size() - returns max size required to store the number
99 *
100 * @a: A multi precision integer for which we want to allocate a buffer
101 *
102 * Return: size required to store the number
103 */
mpi_get_size(MPI a)104 static inline unsigned int mpi_get_size(MPI a)
105 {
106 return a->nlimbs * BYTES_PER_MPI_LIMB;
107 }
108 #endif /*G10_MPI_H */
109