1 /*
2 * Copyright 1995-2023 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 = 0, failed = 0;
53 BN_MONT_CTX *mont = NULL;
54
55 if (!TEST_ptr(m = BN_new())
56 || !TEST_ptr(a = BN_new())
57 || !TEST_ptr(p = BN_new())
58 || !TEST_ptr(r = BN_new()))
59 goto err;
60
61 BN_one(m);
62 BN_one(a);
63 BN_zero(p);
64
65 if (!TEST_true(BN_rand(a, 1024, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY)))
66 goto err;
67
68 if (!TEST_true(BN_mod_exp(r, a, p, m, ctx)))
69 goto err;
70
71 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp", r, a)))
72 failed = 1;
73
74 if (!TEST_true(BN_mod_exp_recp(r, a, p, m, ctx)))
75 goto err;
76
77 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_recp", r, a)))
78 failed = 1;
79
80 if (!TEST_true(BN_mod_exp_simple(r, a, p, m, ctx)))
81 goto err;
82
83 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_simple", r, a)))
84 failed = 1;
85
86 if (!TEST_true(BN_mod_exp_mont(r, a, p, m, ctx, NULL)))
87 goto err;
88
89 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_mont", r, a)))
90 failed = 1;
91
92 if (!TEST_true(BN_mod_exp_mont_consttime(r, a, p, m, ctx, NULL)))
93 goto err;
94
95 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_mont_consttime", r, a)))
96 failed = 1;
97
98 if (!TEST_ptr(mont = BN_MONT_CTX_new()))
99 goto err;
100
101 ERR_set_mark();
102 /* mont is not set but passed in */
103 if (!TEST_false(BN_mod_exp_mont_consttime(r, p, a, m, ctx, mont)))
104 goto err;
105 if (!TEST_false(BN_mod_exp_mont(r, p, a, m, ctx, mont)))
106 goto err;
107 ERR_pop_to_mark();
108
109 if (!TEST_true(BN_MONT_CTX_set(mont, m, ctx)))
110 goto err;
111
112 /* we compute 0 ** a mod 1 here, to execute code that uses mont */
113 if (!TEST_true(BN_mod_exp_mont_consttime(r, p, a, m, ctx, mont)))
114 goto err;
115
116 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_mont_consttime", r, a)))
117 failed = 1;
118
119 if (!TEST_true(BN_mod_exp_mont(r, p, a, m, ctx, mont)))
120 goto err;
121
122 if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_mont", r, a)))
123 failed = 1;
124
125 /*
126 * A different codepath exists for single word multiplication
127 * in non-constant-time only.
128 */
129 if (!TEST_true(BN_mod_exp_mont_word(r, one_word, p, m, ctx, NULL)))
130 goto err;
131
132 if (!TEST_BN_eq_zero(r)) {
133 TEST_error("BN_mod_exp_mont_word failed: "
134 "1 ** 0 mod 1 = r (should be 0)");
135 BN_print_var(r);
136 goto err;
137 }
138
139 ret = !failed;
140 err:
141 BN_free(r);
142 BN_free(a);
143 BN_free(p);
144 BN_free(m);
145 BN_MONT_CTX_free(mont);
146 BN_CTX_free(ctx);
147
148 return ret;
149 }
150
test_mod_exp(int round)151 static int test_mod_exp(int round)
152 {
153 BN_CTX *ctx;
154 unsigned char c;
155 int ret = 0;
156 BIGNUM *r_mont = NULL;
157 BIGNUM *r_mont_const = NULL;
158 BIGNUM *r_recp = NULL;
159 BIGNUM *r_simple = NULL;
160 BIGNUM *a = NULL;
161 BIGNUM *b = NULL;
162 BIGNUM *m = NULL;
163
164 if (!TEST_ptr(ctx = BN_CTX_new()))
165 goto err;
166
167 if (!TEST_ptr(r_mont = BN_new())
168 || !TEST_ptr(r_mont_const = BN_new())
169 || !TEST_ptr(r_recp = BN_new())
170 || !TEST_ptr(r_simple = BN_new())
171 || !TEST_ptr(a = BN_new())
172 || !TEST_ptr(b = BN_new())
173 || !TEST_ptr(m = BN_new()))
174 goto err;
175
176 if (!TEST_int_gt(RAND_bytes(&c, 1), 0))
177 goto err;
178 c = (c % BN_BITS) - BN_BITS2;
179 if (!TEST_true(BN_rand(a, NUM_BITS + c, BN_RAND_TOP_ONE,
180 BN_RAND_BOTTOM_ANY)))
181 goto err;
182
183 if (!TEST_int_gt(RAND_bytes(&c, 1), 0))
184 goto err;
185 c = (c % BN_BITS) - BN_BITS2;
186 if (!TEST_true(BN_rand(b, NUM_BITS + c, BN_RAND_TOP_ONE,
187 BN_RAND_BOTTOM_ANY)))
188 goto err;
189
190 if (!TEST_int_gt(RAND_bytes(&c, 1), 0))
191 goto err;
192 c = (c % BN_BITS) - BN_BITS2;
193 if (!TEST_true(BN_rand(m, NUM_BITS + c, BN_RAND_TOP_ONE,
194 BN_RAND_BOTTOM_ODD)))
195 goto err;
196
197 if (!TEST_true(BN_mod(a, a, m, ctx))
198 || !TEST_true(BN_mod(b, b, m, ctx))
199 || !TEST_true(BN_mod_exp_mont(r_mont, a, b, m, ctx, NULL))
200 || !TEST_true(BN_mod_exp_recp(r_recp, a, b, m, ctx))
201 || !TEST_true(BN_mod_exp_simple(r_simple, a, b, m, ctx))
202 || !TEST_true(BN_mod_exp_mont_consttime(r_mont_const, a, b, m, ctx, NULL)))
203 goto err;
204
205 if (!TEST_BN_eq(r_simple, r_mont)
206 || !TEST_BN_eq(r_simple, r_recp)
207 || !TEST_BN_eq(r_simple, r_mont_const)) {
208 if (BN_cmp(r_simple, r_mont) != 0)
209 TEST_info("simple and mont results differ");
210 if (BN_cmp(r_simple, r_mont_const) != 0)
211 TEST_info("simple and mont const time results differ");
212 if (BN_cmp(r_simple, r_recp) != 0)
213 TEST_info("simple and recp results differ");
214
215 BN_print_var(a);
216 BN_print_var(b);
217 BN_print_var(m);
218 BN_print_var(r_simple);
219 BN_print_var(r_recp);
220 BN_print_var(r_mont);
221 BN_print_var(r_mont_const);
222 goto err;
223 }
224
225 ret = 1;
226 err:
227 BN_free(r_mont);
228 BN_free(r_mont_const);
229 BN_free(r_recp);
230 BN_free(r_simple);
231 BN_free(a);
232 BN_free(b);
233 BN_free(m);
234 BN_CTX_free(ctx);
235
236 return ret;
237 }
238
test_mod_exp_x2(int idx)239 static int test_mod_exp_x2(int idx)
240 {
241 BN_CTX *ctx;
242 int ret = 0;
243 BIGNUM *r_mont_const_x2_1 = NULL;
244 BIGNUM *r_mont_const_x2_2 = NULL;
245 BIGNUM *r_simple1 = NULL;
246 BIGNUM *r_simple2 = NULL;
247 BIGNUM *a1 = NULL;
248 BIGNUM *b1 = NULL;
249 BIGNUM *m1 = NULL;
250 BIGNUM *a2 = NULL;
251 BIGNUM *b2 = NULL;
252 BIGNUM *m2 = NULL;
253 int factor_size = 0;
254
255 if (idx <= 100)
256 factor_size = 1024;
257 else if (idx <= 200)
258 factor_size = 1536;
259 else if (idx <= 300)
260 factor_size = 2048;
261
262 if (!TEST_ptr(ctx = BN_CTX_new()))
263 goto err;
264
265 if (!TEST_ptr(r_mont_const_x2_1 = BN_new())
266 || !TEST_ptr(r_mont_const_x2_2 = BN_new())
267 || !TEST_ptr(r_simple1 = BN_new())
268 || !TEST_ptr(r_simple2 = BN_new())
269 || !TEST_ptr(a1 = BN_new())
270 || !TEST_ptr(b1 = BN_new())
271 || !TEST_ptr(m1 = BN_new())
272 || !TEST_ptr(a2 = BN_new())
273 || !TEST_ptr(b2 = BN_new())
274 || !TEST_ptr(m2 = BN_new()))
275 goto err;
276
277 BN_rand(a1, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);
278 BN_rand(b1, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);
279 BN_rand(m1, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD);
280 BN_rand(a2, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);
281 BN_rand(b2, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);
282 BN_rand(m2, factor_size, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD);
283
284 if (!TEST_true(BN_mod(a1, a1, m1, ctx))
285 || !TEST_true(BN_mod(b1, b1, m1, ctx))
286 || !TEST_true(BN_mod(a2, a2, m2, ctx))
287 || !TEST_true(BN_mod(b2, b2, m2, ctx))
288 || !TEST_true(BN_mod_exp_simple(r_simple1, a1, b1, m1, ctx))
289 || !TEST_true(BN_mod_exp_simple(r_simple2, a2, b2, m2, ctx))
290 || !TEST_true(BN_mod_exp_mont_consttime_x2(r_mont_const_x2_1, a1, b1, m1, NULL,
291 r_mont_const_x2_2, a2, b2, m2, NULL,
292 ctx)))
293 goto err;
294
295 if (!TEST_BN_eq(r_simple1, r_mont_const_x2_1)
296 || !TEST_BN_eq(r_simple2, r_mont_const_x2_2)) {
297 if (BN_cmp(r_simple1, r_mont_const_x2_1) != 0)
298 TEST_info("simple and mont const time x2 (#1) results differ");
299 if (BN_cmp(r_simple2, r_mont_const_x2_2) != 0)
300 TEST_info("simple and mont const time x2 (#2) results differ");
301
302 BN_print_var(a1);
303 BN_print_var(b1);
304 BN_print_var(m1);
305 BN_print_var(a2);
306 BN_print_var(b2);
307 BN_print_var(m2);
308 BN_print_var(r_simple1);
309 BN_print_var(r_simple2);
310 BN_print_var(r_mont_const_x2_1);
311 BN_print_var(r_mont_const_x2_2);
312 goto err;
313 }
314
315 ret = 1;
316 err:
317 BN_free(r_mont_const_x2_1);
318 BN_free(r_mont_const_x2_2);
319 BN_free(r_simple1);
320 BN_free(r_simple2);
321 BN_free(a1);
322 BN_free(b1);
323 BN_free(m1);
324 BN_free(a2);
325 BN_free(b2);
326 BN_free(m2);
327 BN_CTX_free(ctx);
328
329 return ret;
330 }
331
setup_tests(void)332 int setup_tests(void)
333 {
334 ADD_TEST(test_mod_exp_zero);
335 ADD_ALL_TESTS(test_mod_exp, 200);
336 ADD_ALL_TESTS(test_mod_exp_x2, 300);
337 return 1;
338 }
339
