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