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465ae836 | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
5ce3e312 DK |
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 | * | |
5ce3e312 DK |
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> | |
2d4d1eea | 21 | #include <linux/scatterlist.h> |
5ce3e312 | 22 | |
5ce3e312 DK |
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 | ||
5ce3e312 | 42 | #define mpi_get_nlimbs(a) ((a)->nlimbs) |
a8ea8bdd | 43 | #define mpi_has_sign(a) ((a)->sign) |
5ce3e312 DK |
44 | |
45 | /*-- mpiutil.c --*/ | |
46 | MPI mpi_alloc(unsigned nlimbs); | |
a8ea8bdd | 47 | void mpi_clear(MPI a); |
5ce3e312 DK |
48 | void mpi_free(MPI a); |
49 | int mpi_resize(MPI a, unsigned nlimbs); | |
5ce3e312 | 50 | |
a8ea8bdd TZ |
51 | static inline MPI mpi_new(unsigned int nbits) |
52 | { | |
53 | return mpi_alloc((nbits + BITS_PER_MPI_LIMB - 1) / BITS_PER_MPI_LIMB); | |
54 | } | |
55 | ||
56 | MPI mpi_copy(MPI a); | |
57 | MPI mpi_alloc_like(MPI a); | |
58 | void mpi_snatch(MPI w, MPI u); | |
59 | MPI mpi_set(MPI w, MPI u); | |
60 | MPI mpi_set_ui(MPI w, unsigned long u); | |
61 | MPI mpi_alloc_set_ui(unsigned long u); | |
62 | void 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 | |
68 | enum 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 | ||
77 | MPI mpi_const(enum gcry_mpi_constants no); | |
78 | ||
5ce3e312 | 79 | /*-- mpicoder.c --*/ |
a8ea8bdd TZ |
80 | |
81 | /* Different formats of external big integer representation. */ | |
82 | enum 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 | ||
e1045992 | 92 | MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes); |
5ce3e312 | 93 | MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread); |
a8ea8bdd TZ |
94 | int mpi_fromstr(MPI val, const char *str); |
95 | MPI mpi_scanval(const char *string); | |
2d4d1eea | 96 | MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len); |
5ce3e312 | 97 | void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign); |
d37e2969 TS |
98 | int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes, |
99 | int *sign); | |
9b45b7bb | 100 | int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes, |
2d4d1eea | 101 | int *sign); |
a8ea8bdd TZ |
102 | int mpi_print(enum gcry_mpi_format format, unsigned char *buffer, |
103 | size_t buflen, size_t *nwritten, MPI a); | |
104 | ||
105 | /*-- mpi-mod.c --*/ | |
106 | void mpi_mod(MPI rem, MPI dividend, MPI divisor); | |
107 | ||
108 | /* Context used with Barrett reduction. */ | |
109 | struct barrett_ctx_s; | |
110 | typedef struct barrett_ctx_s *mpi_barrett_t; | |
111 | ||
112 | mpi_barrett_t mpi_barrett_init(MPI m, int copy); | |
113 | void mpi_barrett_free(mpi_barrett_t ctx); | |
114 | void mpi_mod_barrett(MPI r, MPI x, mpi_barrett_t ctx); | |
115 | void mpi_mul_barrett(MPI w, MPI u, MPI v, mpi_barrett_t ctx); | |
5ce3e312 | 116 | |
5ce3e312 | 117 | /*-- mpi-pow.c --*/ |
5ce3e312 DK |
118 | int mpi_powm(MPI res, MPI base, MPI exp, MPI mod); |
119 | ||
5ce3e312 DK |
120 | /*-- mpi-cmp.c --*/ |
121 | int mpi_cmp_ui(MPI u, ulong v); | |
122 | int mpi_cmp(MPI u, MPI v); | |
a8ea8bdd | 123 | int mpi_cmpabs(MPI u, MPI v); |
5ce3e312 | 124 | |
4278e9d9 MHC |
125 | /*-- mpi-sub-ui.c --*/ |
126 | int mpi_sub_ui(MPI w, MPI u, unsigned long vval); | |
127 | ||
5ce3e312 DK |
128 | /*-- mpi-bit.c --*/ |
129 | void mpi_normalize(MPI a); | |
130 | unsigned mpi_get_nbits(MPI a); | |
a8ea8bdd TZ |
131 | int mpi_test_bit(MPI a, unsigned int n); |
132 | void mpi_set_bit(MPI a, unsigned int n); | |
133 | void mpi_set_highbit(MPI a, unsigned int n); | |
134 | void mpi_clear_highbit(MPI a, unsigned int n); | |
135 | void mpi_clear_bit(MPI a, unsigned int n); | |
136 | void mpi_rshift_limbs(MPI a, unsigned int count); | |
137 | void mpi_rshift(MPI x, MPI a, unsigned int n); | |
138 | void mpi_lshift_limbs(MPI a, unsigned int count); | |
139 | void mpi_lshift(MPI x, MPI a, unsigned int n); | |
140 | ||
141 | /*-- mpi-add.c --*/ | |
142 | void mpi_add_ui(MPI w, MPI u, unsigned long v); | |
143 | void mpi_add(MPI w, MPI u, MPI v); | |
144 | void mpi_sub(MPI w, MPI u, MPI v); | |
145 | void mpi_addm(MPI w, MPI u, MPI v, MPI m); | |
146 | void mpi_subm(MPI w, MPI u, MPI v, MPI m); | |
147 | ||
148 | /*-- mpi-mul.c --*/ | |
149 | void mpi_mul(MPI w, MPI u, MPI v); | |
150 | void mpi_mulm(MPI w, MPI u, MPI v, MPI m); | |
151 | ||
152 | /*-- mpi-div.c --*/ | |
153 | void mpi_tdiv_r(MPI rem, MPI num, MPI den); | |
154 | void mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor); | |
155 | void mpi_fdiv_q(MPI quot, MPI dividend, MPI divisor); | |
156 | ||
157 | /*-- mpi-inv.c --*/ | |
158 | int mpi_invm(MPI x, MPI a, MPI n); | |
5ce3e312 | 159 | |
d58bb7e5 TZ |
160 | /*-- ec.c --*/ |
161 | ||
162 | /* Object to represent a point in projective coordinates */ | |
163 | struct gcry_mpi_point { | |
164 | MPI x; | |
165 | MPI y; | |
166 | MPI z; | |
167 | }; | |
168 | ||
169 | typedef struct gcry_mpi_point *MPI_POINT; | |
170 | ||
171 | /* Models describing an elliptic curve */ | |
172 | enum 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 */ | |
189 | enum 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. */ | |
196 | struct 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 flaged 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 | ||
248 | void 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); | |
251 | void mpi_ec_deinit(struct mpi_ec_ctx *ctx); | |
252 | MPI_POINT mpi_point_new(unsigned int nbits); | |
253 | void mpi_point_release(MPI_POINT p); | |
254 | void mpi_point_init(MPI_POINT p); | |
255 | void mpi_point_free_parts(MPI_POINT p); | |
256 | int mpi_ec_get_affine(MPI x, MPI y, MPI_POINT point, struct mpi_ec_ctx *ctx); | |
257 | void mpi_ec_add_points(MPI_POINT result, | |
258 | MPI_POINT p1, MPI_POINT p2, | |
259 | struct mpi_ec_ctx *ctx); | |
260 | void mpi_ec_mul_point(MPI_POINT result, | |
261 | MPI scalar, MPI_POINT point, | |
262 | struct mpi_ec_ctx *ctx); | |
263 | int mpi_ec_curve_point(MPI_POINT point, struct mpi_ec_ctx *ctx); | |
264 | ||
d37e2969 TS |
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 bufer | |
271 | * | |
272 | * Return: size required to store the number | |
273 | */ | |
274 | static inline unsigned int mpi_get_size(MPI a) | |
275 | { | |
276 | return a->nlimbs * BYTES_PER_MPI_LIMB; | |
277 | } | |
5ce3e312 | 278 | #endif /*G10_MPI_H */ |