1 /*
2 * Copyright 1995-2022 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <stdio.h>
11 #include <stdlib.h>
12 #include <string.h>
13
14 #include "internal/nelem.h"
15
16 #include <openssl/bio.h>
17 #include <openssl/bn.h>
18 #include <openssl/rand.h>
19 #include <openssl/err.h>
20
21 #include "testutil.h"
22
23 #define NUM_BITS (BN_BITS2 * 4)
24
25 #define BN_print_var(v) test_output_bignum(#v, v)
26
27 /*
28 * Test that r == 0 in test_exp_mod_zero(). Returns one on success,
29 * returns zero and prints debug output otherwise.
30 */
a_is_zero_mod_one(const char * method,const BIGNUM * r,const BIGNUM * a)31 static int a_is_zero_mod_one(const char *method, const BIGNUM *r,
32 const BIGNUM *a)
33 {
34 if (!BN_is_zero(r)) {
35 TEST_error("%s failed: a ** 0 mod 1 = r (should be 0)", method);
36 BN_print_var(a);
37 BN_print_var(r);
38 return 0;
39 }
40 return 1;
41 }
42
43 /*
44 * test_mod_exp_zero tests that x**0 mod 1 == 0. It returns zero on success.
45 */
test_mod_exp_zero(void)46 static int test_mod_exp_zero(void)
47 {
48 BIGNUM *a = NULL, *p = NULL, *m = NULL;
49 BIGNUM *r = NULL;
50 BN_ULONG one_word = 1;
51 BN_CTX *ctx = BN_CTX_new();
52 int ret = 1, failed = 0;
53
54 if (!TEST_ptr(m = BN_new())
55 || !TEST_ptr(a = BN_new())
56 || !TEST_ptr(p = BN_new())
57 || !TEST_ptr(r = BN_new()))
58 goto err;
59
60 BN_one(m);
61 BN_one(a);
62 BN_zero(p);
63
64 if (!TEST_true(BN_rand(a, 1024, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY)))
65 goto err;
66
67 if (!TEST_true(BN_mod_exp(r, a, p, m, ctx)))
68 goto err;
69
70 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp", r, a)))
71 failed = 1;
72
73 if (!TEST_true(BN_mod_exp_recp(r, a, p, m, ctx)))
74 goto err;
75
76 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_recp", r, a)))
77 failed = 1;
78
79 if (!TEST_true(BN_mod_exp_simple(r, a, p, m, ctx)))
80 goto err;
81
82 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_simple", r, a)))
83 failed = 1;
84
85 if (!TEST_true(BN_mod_exp_mont(r, a, p, m, ctx, NULL)))
86 goto err;
87
88 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_mont", r, a)))
89 failed = 1;
90
91 if (!TEST_true(BN_mod_exp_mont_consttime(r, a, p, m, ctx, NULL)))
92 goto err;
93
94 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_mont_consttime", r, a)))
95 failed = 1;
96
97 /*
98 * A different codepath exists for single word multiplication
99 * in non-constant-time only.
100 */
101 if (!TEST_true(BN_mod_exp_mont_word(r, one_word, p, m, ctx, NULL)))
102 goto err;
103
104 if (!TEST_BN_eq_zero(r)) {
105 TEST_error("BN_mod_exp_mont_word failed: "
106 "1 ** 0 mod 1 = r (should be 0)");
107 BN_print_var(r);
108 goto err;
109 }
110
111 ret = !failed;
112 err:
113 BN_free(r);
114 BN_free(a);
115 BN_free(p);
116 BN_free(m);
117 BN_CTX_free(ctx);
118
119 return ret;
120 }
121
test_mod_exp(int round)122 static int test_mod_exp(int round)
123 {
124 BN_CTX *ctx;
125 unsigned char c;
126 int ret = 0;
127 BIGNUM *r_mont = NULL;
128 BIGNUM *r_mont_const = NULL;
129 BIGNUM *r_recp = NULL;
130 BIGNUM *r_simple = NULL;
131 BIGNUM *a = NULL;
132 BIGNUM *b = NULL;
133 BIGNUM *m = NULL;
134
135 if (!TEST_ptr(ctx = BN_CTX_new()))
136 goto err;
137
138 if (!TEST_ptr(r_mont = BN_new())
139 || !TEST_ptr(r_mont_const = BN_new())
140 || !TEST_ptr(r_recp = BN_new())
141 || !TEST_ptr(r_simple = BN_new())
142 || !TEST_ptr(a = BN_new())
143 || !TEST_ptr(b = BN_new())
144 || !TEST_ptr(m = BN_new()))
145 goto err;
146
147 if (!TEST_int_gt(RAND_bytes(&c, 1), 0))
148 goto err;
149 c = (c % BN_BITS) - BN_BITS2;
150 if (!TEST_true(BN_rand(a, NUM_BITS + c, BN_RAND_TOP_ONE,
151 BN_RAND_BOTTOM_ANY)))
152 goto err;
153
154 if (!TEST_int_gt(RAND_bytes(&c, 1), 0))
155 goto err;
156 c = (c % BN_BITS) - BN_BITS2;
157 if (!TEST_true(BN_rand(b, NUM_BITS + c, BN_RAND_TOP_ONE,
158 BN_RAND_BOTTOM_ANY)))
159 goto err;
160
161 if (!TEST_int_gt(RAND_bytes(&c, 1), 0))
162 goto err;
163 c = (c % BN_BITS) - BN_BITS2;
164 if (!TEST_true(BN_rand(m, NUM_BITS + c, BN_RAND_TOP_ONE,
165 BN_RAND_BOTTOM_ODD)))
166 goto err;
167
168 if (!TEST_true(BN_mod(a, a, m, ctx))
169 || !TEST_true(BN_mod(b, b, m, ctx))
170 || !TEST_true(BN_mod_exp_mont(r_mont, a, b, m, ctx, NULL))
171 || !TEST_true(BN_mod_exp_recp(r_recp, a, b, m, ctx))
172 || !TEST_true(BN_mod_exp_simple(r_simple, a, b, m, ctx))
173 || !TEST_true(BN_mod_exp_mont_consttime(r_mont_const, a, b, m, ctx, NULL)))
174 goto err;
175
176 if (!TEST_BN_eq(r_simple, r_mont)
177 || !TEST_BN_eq(r_simple, r_recp)
178 || !TEST_BN_eq(r_simple, r_mont_const)) {
179 if (BN_cmp(r_simple, r_mont) != 0)
180 TEST_info("simple and mont results differ");
181 if (BN_cmp(r_simple, r_mont_const) != 0)
182 TEST_info("simple and mont const time results differ");
183 if (BN_cmp(r_simple, r_recp) != 0)
184 TEST_info("simple and recp results differ");
185
186 BN_print_var(a);
187 BN_print_var(b);
188 BN_print_var(m);
189 BN_print_var(r_simple);
190 BN_print_var(r_recp);
191 BN_print_var(r_mont);
192 BN_print_var(r_mont_const);
193 goto err;
194 }
195
196 ret = 1;
197 err:
198 BN_free(r_mont);
199 BN_free(r_mont_const);
200 BN_free(r_recp);
201 BN_free(r_simple);
202 BN_free(a);
203 BN_free(b);
204 BN_free(m);
205 BN_CTX_free(ctx);
206
207 return ret;
208 }
209
test_mod_exp_x2(int idx)210 static int test_mod_exp_x2(int idx)
211 {
212 BN_CTX *ctx;
213 int ret = 0;
214 BIGNUM *r_mont_const_x2_1 = NULL;
215 BIGNUM *r_mont_const_x2_2 = NULL;
216 BIGNUM *r_simple1 = NULL;
217 BIGNUM *r_simple2 = NULL;
218 BIGNUM *a1 = NULL;
219 BIGNUM *b1 = NULL;
220 BIGNUM *m1 = NULL;
221 BIGNUM *a2 = NULL;
222 BIGNUM *b2 = NULL;
223 BIGNUM *m2 = NULL;
224 int factor_size = 0;
225
226 /*
227 * Currently only 1024-bit factor size is supported.
228 */
229 if (idx <= 100)
230 factor_size = 1024;
231
232 if (!TEST_ptr(ctx = BN_CTX_new()))
233 goto err;
234
235 if (!TEST_ptr(r_mont_const_x2_1 = BN_new())
236 || !TEST_ptr(r_mont_const_x2_2 = BN_new())
237 || !TEST_ptr(r_simple1 = BN_new())
238 || !TEST_ptr(r_simple2 = BN_new())
239 || !TEST_ptr(a1 = BN_new())
240 || !TEST_ptr(b1 = BN_new())
241 || !TEST_ptr(m1 = BN_new())
242 || !TEST_ptr(a2 = BN_new())
243 || !TEST_ptr(b2 = BN_new())
244 || !TEST_ptr(m2 = BN_new()))
245 goto err;
246
247 BN_rand(a1, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);
248 BN_rand(b1, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);
249 BN_rand(m1, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD);
250 BN_rand(a2, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);
251 BN_rand(b2, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);
252 BN_rand(m2, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD);
253
254 if (!TEST_true(BN_mod(a1, a1, m1, ctx))
255 || !TEST_true(BN_mod(b1, b1, m1, ctx))
256 || !TEST_true(BN_mod(a2, a2, m2, ctx))
257 || !TEST_true(BN_mod(b2, b2, m2, ctx))
258 || !TEST_true(BN_mod_exp_simple(r_simple1, a1, b1, m1, ctx))
259 || !TEST_true(BN_mod_exp_simple(r_simple2, a2, b2, m2, ctx))
260 || !TEST_true(BN_mod_exp_mont_consttime_x2(r_mont_const_x2_1, a1, b1, m1, NULL,
261 r_mont_const_x2_2, a2, b2, m2, NULL,
262 ctx)))
263 goto err;
264
265 if (!TEST_BN_eq(r_simple1, r_mont_const_x2_1)
266 || !TEST_BN_eq(r_simple2, r_mont_const_x2_2)) {
267 if (BN_cmp(r_simple1, r_mont_const_x2_1) != 0)
268 TEST_info("simple and mont const time x2 (#1) results differ");
269 if (BN_cmp(r_simple2, r_mont_const_x2_2) != 0)
270 TEST_info("simple and mont const time x2 (#2) results differ");
271
272 BN_print_var(a1);
273 BN_print_var(b1);
274 BN_print_var(m1);
275 BN_print_var(a2);
276 BN_print_var(b2);
277 BN_print_var(m2);
278 BN_print_var(r_simple1);
279 BN_print_var(r_simple2);
280 BN_print_var(r_mont_const_x2_1);
281 BN_print_var(r_mont_const_x2_2);
282 goto err;
283 }
284
285 ret = 1;
286 err:
287 BN_free(r_mont_const_x2_1);
288 BN_free(r_mont_const_x2_2);
289 BN_free(r_simple1);
290 BN_free(r_simple2);
291 BN_free(a1);
292 BN_free(b1);
293 BN_free(m1);
294 BN_free(a2);
295 BN_free(b2);
296 BN_free(m2);
297 BN_CTX_free(ctx);
298
299 return ret;
300 }
301
setup_tests(void)302 int setup_tests(void)
303 {
304 ADD_TEST(test_mod_exp_zero);
305 ADD_ALL_TESTS(test_mod_exp, 200);
306 ADD_ALL_TESTS(test_mod_exp_x2, 100);
307 return 1;
308 }
309