1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* mpi-internal.h - Internal to the Multi Precision Integers
3 * Copyright (C) 1994, 1996 Free Software Foundation, Inc.
4 * Copyright (C) 1998, 2000 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_INTERNAL_H
18 #define G10_MPI_INTERNAL_H
19
20 #include <linux/module.h>
21 #include <linux/kernel.h>
22 #include <linux/slab.h>
23 #include <linux/string.h>
24 #include <linux/mpi.h>
25 #include <linux/errno.h>
26
27 #define log_debug printk
28 #define log_bug printk
29
30 #define assert(x) \
31 do { \
32 if (!x) \
33 log_bug("failed assertion\n"); \
34 } while (0);
35
36 /* If KARATSUBA_THRESHOLD is not already defined, define it to a
37 * value which is good on most machines. */
38
39 /* tested 4, 16, 32 and 64, where 16 gave the best performance when
40 * checking a 768 and a 1024 bit ElGamal signature.
41 * (wk 22.12.97) */
42 #ifndef KARATSUBA_THRESHOLD
43 #define KARATSUBA_THRESHOLD 16
44 #endif
45
46 /* The code can't handle KARATSUBA_THRESHOLD smaller than 2. */
47 #if KARATSUBA_THRESHOLD < 2
48 #undef KARATSUBA_THRESHOLD
49 #define KARATSUBA_THRESHOLD 2
50 #endif
51
52 typedef mpi_limb_t *mpi_ptr_t; /* pointer to a limb */
53 typedef int mpi_size_t; /* (must be a signed type) */
54
55 #define RESIZE_IF_NEEDED(a, b) \
56 do { \
57 if ((a)->alloced < (b)) \
58 mpi_resize((a), (b)); \
59 } while (0)
60
61 /* Copy N limbs from S to D. */
62 #define MPN_COPY(d, s, n) \
63 do { \
64 mpi_size_t _i; \
65 for (_i = 0; _i < (n); _i++) \
66 (d)[_i] = (s)[_i]; \
67 } while (0)
68
69 #define MPN_COPY_INCR(d, s, n) \
70 do { \
71 mpi_size_t _i; \
72 for (_i = 0; _i < (n); _i++) \
73 (d)[_i] = (s)[_i]; \
74 } while (0)
75
76
77 #define MPN_COPY_DECR(d, s, n) \
78 do { \
79 mpi_size_t _i; \
80 for (_i = (n)-1; _i >= 0; _i--) \
81 (d)[_i] = (s)[_i]; \
82 } while (0)
83
84 /* Zero N limbs at D */
85 #define MPN_ZERO(d, n) \
86 do { \
87 int _i; \
88 for (_i = 0; _i < (n); _i++) \
89 (d)[_i] = 0; \
90 } while (0)
91
92 #define MPN_NORMALIZE(d, n) \
93 do { \
94 while ((n) > 0) { \
95 if ((d)[(n)-1]) \
96 break; \
97 (n)--; \
98 } \
99 } while (0)
100
101 #define MPN_MUL_N_RECURSE(prodp, up, vp, size, tspace) \
102 do { \
103 if ((size) < KARATSUBA_THRESHOLD) \
104 mul_n_basecase(prodp, up, vp, size); \
105 else \
106 mul_n(prodp, up, vp, size, tspace); \
107 } while (0);
108
109 /* Divide the two-limb number in (NH,,NL) by D, with DI being the largest
110 * limb not larger than (2**(2*BITS_PER_MP_LIMB))/D - (2**BITS_PER_MP_LIMB).
111 * If this would yield overflow, DI should be the largest possible number
112 * (i.e., only ones). For correct operation, the most significant bit of D
113 * has to be set. Put the quotient in Q and the remainder in R.
114 */
115 #define UDIV_QRNND_PREINV(q, r, nh, nl, d, di) \
116 do { \
117 mpi_limb_t _ql __maybe_unused; \
118 mpi_limb_t _q, _r; \
119 mpi_limb_t _xh, _xl; \
120 umul_ppmm(_q, _ql, (nh), (di)); \
121 _q += (nh); /* DI is 2**BITS_PER_MPI_LIMB too small */ \
122 umul_ppmm(_xh, _xl, _q, (d)); \
123 sub_ddmmss(_xh, _r, (nh), (nl), _xh, _xl); \
124 if (_xh) { \
125 sub_ddmmss(_xh, _r, _xh, _r, 0, (d)); \
126 _q++; \
127 if (_xh) { \
128 sub_ddmmss(_xh, _r, _xh, _r, 0, (d)); \
129 _q++; \
130 } \
131 } \
132 if (_r >= (d)) { \
133 _r -= (d); \
134 _q++; \
135 } \
136 (r) = _r; \
137 (q) = _q; \
138 } while (0)
139
140
141 /*-- mpiutil.c --*/
142 mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs);
143 void mpi_free_limb_space(mpi_ptr_t a);
144 void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs);
145
146 static inline mpi_limb_t mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
147 mpi_size_t s1_size, mpi_limb_t s2_limb);
148 mpi_limb_t mpihelp_add_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
149 mpi_ptr_t s2_ptr, mpi_size_t size);
150 static inline mpi_limb_t mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
151 mpi_ptr_t s2_ptr, mpi_size_t s2_size);
152
153 static inline mpi_limb_t mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
154 mpi_size_t s1_size, mpi_limb_t s2_limb);
155 mpi_limb_t mpihelp_sub_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
156 mpi_ptr_t s2_ptr, mpi_size_t size);
157 static inline mpi_limb_t mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
158 mpi_ptr_t s2_ptr, mpi_size_t s2_size);
159
160 /*-- mpih-cmp.c --*/
161 int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size);
162
163 /*-- mpih-mul.c --*/
164
165 struct karatsuba_ctx {
166 struct karatsuba_ctx *next;
167 mpi_ptr_t tspace;
168 mpi_size_t tspace_size;
169 mpi_ptr_t tp;
170 mpi_size_t tp_size;
171 };
172
173 void mpihelp_release_karatsuba_ctx(struct karatsuba_ctx *ctx);
174
175 mpi_limb_t mpihelp_addmul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
176 mpi_size_t s1_size, mpi_limb_t s2_limb);
177 mpi_limb_t mpihelp_submul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
178 mpi_size_t s1_size, mpi_limb_t s2_limb);
179 int mpihelp_mul(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t usize,
180 mpi_ptr_t vp, mpi_size_t vsize, mpi_limb_t *_result);
181 void mpih_sqr_n_basecase(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size);
182 void mpih_sqr_n(mpi_ptr_t prodp, mpi_ptr_t up, mpi_size_t size,
183 mpi_ptr_t tspace);
184 void mpihelp_mul_n(mpi_ptr_t prodp,
185 mpi_ptr_t up, mpi_ptr_t vp, mpi_size_t size);
186
187 int mpihelp_mul_karatsuba_case(mpi_ptr_t prodp,
188 mpi_ptr_t up, mpi_size_t usize,
189 mpi_ptr_t vp, mpi_size_t vsize,
190 struct karatsuba_ctx *ctx);
191
192 /*-- generic_mpih-mul1.c --*/
193 mpi_limb_t mpihelp_mul_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
194 mpi_size_t s1_size, mpi_limb_t s2_limb);
195
196 /*-- mpih-div.c --*/
197 mpi_limb_t mpihelp_mod_1(mpi_ptr_t dividend_ptr, mpi_size_t dividend_size,
198 mpi_limb_t divisor_limb);
199 mpi_limb_t mpihelp_divrem(mpi_ptr_t qp, mpi_size_t qextra_limbs,
200 mpi_ptr_t np, mpi_size_t nsize,
201 mpi_ptr_t dp, mpi_size_t dsize);
202 mpi_limb_t mpihelp_divmod_1(mpi_ptr_t quot_ptr,
203 mpi_ptr_t dividend_ptr, mpi_size_t dividend_size,
204 mpi_limb_t divisor_limb);
205
206 /*-- generic_mpih-[lr]shift.c --*/
207 mpi_limb_t mpihelp_lshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize,
208 unsigned cnt);
209 mpi_limb_t mpihelp_rshift(mpi_ptr_t wp, mpi_ptr_t up, mpi_size_t usize,
210 unsigned cnt);
211
212 /* Define stuff for longlong.h. */
213 #define W_TYPE_SIZE BITS_PER_MPI_LIMB
214 typedef mpi_limb_t UWtype;
215 typedef unsigned int UHWtype;
216 #if defined(__GNUC__)
217 typedef unsigned int UQItype __attribute__ ((mode(QI)));
218 typedef int SItype __attribute__ ((mode(SI)));
219 typedef unsigned int USItype __attribute__ ((mode(SI)));
220 typedef int DItype __attribute__ ((mode(DI)));
221 typedef unsigned int UDItype __attribute__ ((mode(DI)));
222 #else
223 typedef unsigned char UQItype;
224 typedef long SItype;
225 typedef unsigned long USItype;
226 #endif
227
228 #ifdef __GNUC__
229 #include "mpi-inline.h"
230 #endif
231
232 #endif /*G10_MPI_INTERNAL_H */
233
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