1 /* $OpenBSD: bn_mod_inverse.c,v 1.2 2023/06/04 07:14:47 tb Exp $ */
2
3 /*
4 * Copyright (c) 2023 Theo Buehler <tb@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <err.h>
20 #include <stdio.h>
21
22 #include <openssl/bn.h>
23
24 BIGNUM *BN_mod_inverse(BIGNUM *, const BIGNUM *, const BIGNUM *, BN_CTX *);
25
26 static const struct mod_inv_test {
27 const char *i;
28 const char *a;
29 const char *m;
30 } mod_inv_tests[] = {
31 {
32 .i = "0",
33 .a = "0",
34 .m = "1",
35 },
36 {
37 .i = "0",
38 .a = "1",
39 .m = "1",
40 },
41 {
42 .i = "0",
43 .a = "2",
44 .m = "1",
45 },
46 {
47 .i = "0",
48 .a = "3",
49 .m = "1",
50 },
51 {
52 .i = "64",
53 .a = "54",
54 .m = "e3",
55 },
56 {
57 .i = "13",
58 .a = "2b",
59 .m = "30",
60 },
61 {
62 .i = "2f",
63 .a = "30",
64 .m = "37",
65 },
66 {
67 .i = "4",
68 .a = "13",
69 .m = "4b",
70 },
71 {
72 .i = "1c47",
73 .a = "cd4",
74 .m = "6a21",
75 },
76 {
77 .i = "2b97",
78 .a = "8e7",
79 .m = "49c0",
80 },
81 {
82 .i = "29b9",
83 .a = "fcb",
84 .m = "3092",
85 },
86 {
87 .i = "a83",
88 .a = "14bf",
89 .m = "41ae",
90 },
91 {
92 .i = "18f15fe1",
93 .a = "11b5d53e",
94 .m = "322e92a1",
95 },
96 {
97 .i = "32f9453b",
98 .a = "8af6df6",
99 .m = "33d45eb7",
100 },
101 {
102 .i = "d696369",
103 .a = "c5f89dd5",
104 .m = "fc09c17c",
105 },
106 {
107 .i = "622839d8",
108 .a = "60c2526",
109 .m = "74200493",
110 },
111 {
112 .i = "fb5a8aee7bbc4ef",
113 .a = "24ebd835a70be4e2",
114 .m = "9c7256574e0c5e93",
115 },
116 {
117 .i = "846bc225402419c",
118 .a = "23026003ab1fbdb",
119 .m = "1683cbe32779c59b",
120 },
121 {
122 .i = "5ff84f63a78982f9",
123 .a = "4a2420dc733e1a0f",
124 .m = "a73c6bfabefa09e6",
125 },
126 {
127 .i = "133e74d28ef42b43",
128 .a = "2e9511ae29cdd41",
129 .m = "15234df99f19fcda",
130 },
131 {
132 .i = "46ae1fabe9521e4b99b198fc84396090"
133 "23aa69be2247c0d1e27c2a0ea332f9c5",
134 .a = "6331fec5f01014046788c919ed50dc86"
135 "ac7a80c085f1b6f645dd179c0f0dc9cd",
136 .m = "8ef409de82318259a8655a39293b1e76"
137 "2fa2cc7e0aeb4c59713a1e1fff6af640",
138 },
139 {
140 .i = "444ccea3a7b21677dd294d34de53cc8a"
141 "5b51e69b37782310a00fc6bcc975709b",
142 .a = "679280bd880994c08322143a4ea8a082"
143 "5d0466fda1bb6b3eb86fc8e90747512b",
144 .m = "e4fecab84b365c63a0dab4244ce3f921"
145 "a9c87ec64d69a2031939f55782e99a2e",
146 },
147 {
148 .i = "1ac7d7a03ceec5f690f567c9d61bf346"
149 "9c078285bcc5cf00ac944596e887ca17",
150 .a = "1593ef32d9c784f5091bdff952f5c5f5"
151 "92a3aed6ba8ea865efa6d7df87be1805",
152 .m = "1e276882f90c95e0c1976eb079f97af0"
153 "75445b1361c02018d6bd7191162e67b2",
154 },
155 {
156 .i = "639108b90dfe946f498be21303058413"
157 "bbb0e59d0bd6a6115788705abd0666d6",
158 .a = "9258d6238e4923d120b2d1033573ffca"
159 "c691526ad0842a3b174dccdbb79887bd",
160 .m = "ce62909c39371d463aaba3d4b72ea6da"
161 "49cb9b529e39e1972ef3ccd9a66fe08f",
162 },
163 {
164 .i = "aebde7654cb17833a106231c4b9e2f51"
165 "9140e85faee1bfb4192830f03f385e77"
166 "3c0f4767e93e874ffdc3b7a6b7e6a710"
167 "e5619901c739ee8760a26128e8c91ef8"
168 "cf761d0e505d8b28ae078d17e6071c37"
169 "2893bb7b72538e518ebc57efa70b7615"
170 "e406756c49729b7c6e74f84aed7a316b"
171 "6fa748ff4b9f143129d29dad1bff98bb",
172 .a = "a29dacaf5487d354280fdd2745b9ace4"
173 "cd50f2bde41d0ee529bf26a1913244f7"
174 "08085452ff32feab19a7418897990da4"
175 "6a0633f7c8375d583367319091bbbe06"
176 "9b0052c5e48a7daac9fb650db5af768c"
177 "d2508ec3e2cda7456d4b9ce1c3945962"
178 "7a8b77e038b826cd7e326d0685b0cd0c"
179 "b50f026f18300dae9f5fd42aa150ee8b",
180 .m = "d686f9b86697313251685e995c09b9f1"
181 "e337ddfaa050bd2df15bf4ca1dc46c55"
182 "65021314765299c434ea1a6ec42bf92a"
183 "29a7d1ffff599f4e50b79a82243fb248"
184 "13060580c770d4c1140aeb2ab2685007"
185 "e948b6f1f62e8001a0545619477d4981"
186 "32c907774479f6d95899e6251e7136f7"
187 "9ab6d3b7c82e4aca421e7d22fe7db19c",
188 },
189 {
190 .i = "1ec872f4f20439e203597ca4de9d1296"
191 "743f95781b2fe85d5def808558bbadef"
192 "02a46b8955f47c83e1625f8bb40228ea"
193 "b09cad2a35c9ad62ab77a30e39328729"
194 "59c5898674162da244a0ec1f68c0ed89"
195 "f4b0f3572bfdc658ad15bf1b1c6e1176"
196 "b0784c9935bd3ff1f49bb43753eacee1"
197 "d8ca1c0b652d39ec727da83984fe3a0f",
198 .a = "2e527b0a1dc32460b2dd94ec446c6929"
199 "89f7b3c7451a5cbeebf69fc0ea9c4871"
200 "fbe78682d5dc5b66689f7ed889b52161"
201 "cd9830b589a93d21ab26dbede6c33959"
202 "f5a0f0d107169e2daaac78bac8cf2d41"
203 "a1eb1369cb6dc9e865e73bb2e51b886f"
204 "4e896082db199175e3dde0c4ed826468"
205 "f238a77bd894245d0918efc9ca84f945",
206 .m = "b13133a9ebe0645f987d170c077eea2a"
207 "a44e85c9ab10386d02867419a590cb18"
208 "2d9826a882306c212dbe75225adde23f"
209 "80f5b37ca75ed09df20fc277cc7fbbfa"
210 "c8d9ef37a50f6b68ea158f5447283618"
211 "e64e1426406d26ea85232afb22bf546c"
212 "75018c1c55cb84c374d58d9d44c0a13b"
213 "a88ac2e387765cb4c3269e3a983250fa",
214 },
215 {
216 .i = "30ffa1876313a69de1e4e6ee132ea1d3"
217 "a3da32f3b56f5cfb11402b0ad517dce6"
218 "05cf8e91d69fa375dd887fa8507bd8a2"
219 "8b2d5ce745799126e86f416047709f93"
220 "f07fbd88918a047f13100ea71b1d48f6"
221 "fc6d12e5c917646df3041b302187af64"
222 "1eaedf4908abc36f12c204e1526a7d80"
223 "e96e302fb0779c28d7da607243732f26",
224 .a = "31157208bde6b85ebecaa63735947b3b"
225 "36fa351b5c47e9e1c40c947339b78bf9"
226 "6066e5dbe21bb42629e6fcdb81f5f88d"
227 "b590bfdd5f4c0a6a0c3fc6377e5c1fd8"
228 "235e46e291c688b6d6ecfb36604891c2"
229 "a7c9cbcc58c26e44b43beecb9c5044b5"
230 "8bb58e35de3cf1128f3c116534fe4e42"
231 "1a33f83603c3df1ae36ec88092f67f2a",
232 .m = "53408b23d6cb733e6c9bc3d1e2ea2286"
233 "a5c83cc4e3e7470f8af3a1d9f28727f5"
234 "b1f8ae348c1678f5d1105dc3edf2de64"
235 "e65b9c99545c47e64b770b17c8b4ef5c"
236 "f194b43a0538053e87a6b95ade1439ce"
237 "bf3d34c6aa72a11c1497f58f76011e16"
238 "c5be087936d88aba7a740113120e939e"
239 "27bd3ddcb6580c2841aa406566e33c35",
240 },
241 {
242 .i = "87355002f305c81ba0dc97ca2234a2bc"
243 "02528cefde38b94ac5bd95efc7bf4c14"
244 "0899107fff47f0df9e3c6aa70017ebc9"
245 "0610a750f112cd4f475b9c76b204a953"
246 "444b4e7196ccf17e93fdaed160b7345c"
247 "a9b397eddf9446e8ea8ee3676102ce70"
248 "eaafbe9038a34639789e6f2f1e3f3526"
249 "38f2e8a8f5fc56aaea7ec705ee068dd5",
250 .a = "42a25d0bc96f71750f5ac8a51a1605a4"
251 "1b506cca51c9a7ecf80cad713e56f70f"
252 "1b4b6fa51cbb101f55fd74f318adefb3"
253 "af04e0c8a7e281055d5a40dd40913c0e"
254 "1211767c5be915972c73886106dc4932"
255 "5df6c2df49e9eea4536f0343a8e7d332"
256 "c6159e4f5bdb20d89f90e67597c4a2a6"
257 "32c31b2ef2534080a9ac61f52303990d",
258 .m = "d3d3f95d50570351528a76ab1e806bae"
259 "1968bd420899bdb3d87c823fac439a43"
260 "54c31f6c888c939784f18fe10a95e6d2"
261 "03b1901caa18937ba6f8be033af10c35"
262 "fc869cf3d16bef479f280f53b3499e64"
263 "5d0387554623207ca4989e5de00bfeaa"
264 "5e9ab56474fc60dd4967b100e0832eaa"
265 "f2fcb2ef82a181567057b880b3afef62",
266 },
267 {
268 .i = "9b8c28a4",
269 .a = "135935f57",
270 .m = "c24242ff",
271 },
272 };
273
274 #define N_MOD_INV_TESTS (sizeof(mod_inv_tests) / sizeof(mod_inv_tests[0]))
275
276 static int
bn_mod_inverse_test(const struct mod_inv_test * test,BN_CTX * ctx,int flags)277 bn_mod_inverse_test(const struct mod_inv_test *test, BN_CTX *ctx, int flags)
278 {
279 BIGNUM *i, *a, *m, *inv, *elt, *mod;
280 int failed_step;
281 int failed = 0;
282
283 BN_CTX_start(ctx);
284
285 if ((i = BN_CTX_get(ctx)) == NULL)
286 errx(1, "i = BN_CTX_get()");
287 if ((a = BN_CTX_get(ctx)) == NULL)
288 errx(1, "a = BN_CTX_get()");
289 if ((m = BN_CTX_get(ctx)) == NULL)
290 errx(1, "m = BN_CTX_get()");
291 if ((inv = BN_CTX_get(ctx)) == NULL)
292 errx(1, "inv = BN_CTX_get()");
293 if ((elt = BN_CTX_get(ctx)) == NULL)
294 errx(1, "elt = BN_CTX_get()");
295 if ((mod = BN_CTX_get(ctx)) == NULL)
296 errx(1, "mod = BN_CTX_get()");
297
298 BN_set_flags(i, flags);
299 BN_set_flags(a, flags);
300 BN_set_flags(m, flags);
301 BN_set_flags(inv, flags);
302 BN_set_flags(elt, flags);
303 BN_set_flags(mod, flags);
304
305 if (BN_hex2bn(&i, test->i) == 0)
306 errx(1, "BN_hex2bn(%s)", test->i);
307 if (BN_hex2bn(&a, test->a) == 0)
308 errx(1, "BN_hex2bn(%s)", test->a);
309 if (BN_hex2bn(&m, test->m) == 0)
310 errx(1, "BN_hex2bn(%s)", test->m);
311
312 if (BN_copy(elt, a) == NULL)
313 errx(1, "BN_copy(elt, a)");
314 if (BN_copy(mod, m) == NULL)
315 errx(1, "BN_copy(mod, m)");
316
317 if (BN_mod_inverse(inv, elt, mod, ctx) == NULL)
318 errx(1, "BN_mod_inverse(inv, elt, mod)");
319
320 failed_step = BN_cmp(i, inv) != 0;
321 if (failed_step)
322 fprintf(stderr, "FAIL (simple), %x:\ni: %s\na: %s\nm: %s\n",
323 flags, test->i, test->a, test->m);
324 failed |= failed_step;
325
326 if (BN_copy(elt, a) == NULL)
327 errx(1, "BN_copy(elt, a)");
328 if (BN_copy(inv, m) == NULL)
329 errx(1, "BN_copy(inv, m)");
330
331 if (BN_mod_inverse(inv, elt, inv, ctx) == NULL)
332 errx(1, "BN_mod_inverse(inv, elt, inv)");
333 failed_step = BN_cmp(i, inv) != 0;
334 if (failed_step)
335 fprintf(stderr, "FAIL (inv == mod), %x:\ni: %s\na: %s\nm: %s\n",
336 flags, test->i, test->a, test->m);
337 failed |= failed_step;
338
339 if (BN_copy(inv, a) == NULL)
340 errx(1, "BN_copy(elt, a)");
341 if (BN_copy(mod, m) == NULL)
342 errx(1, "BN_copy(inv, m)");
343
344 if (BN_mod_inverse(inv, inv, mod, ctx) == NULL)
345 errx(1, "BN_mod_inverse(inv, inv, mod)");
346 failed_step = BN_cmp(i, inv) != 0;
347 if (failed_step)
348 fprintf(stderr, "FAIL (inv == elt), %x:\ni: %s\na: %s\nm: %s\n",
349 flags, test->i, test->a, test->m);
350 failed |= failed_step;
351
352 BN_CTX_end(ctx);
353
354 return failed;
355 }
356
357 static int
test_bn_mod_inverse(void)358 test_bn_mod_inverse(void)
359 {
360 BN_CTX *ctx;
361 size_t i;
362 int failed = 0;
363
364 if ((ctx = BN_CTX_new()) == NULL)
365 errx(1, "BN_CTX_new");
366
367 for (i = 0; i < N_MOD_INV_TESTS; i++)
368 failed |= bn_mod_inverse_test(&mod_inv_tests[i], ctx, 0);
369
370 for (i = 0; i < N_MOD_INV_TESTS; i++)
371 failed |= bn_mod_inverse_test(&mod_inv_tests[i], ctx,
372 BN_FLG_CONSTTIME);
373
374 BN_CTX_free(ctx);
375
376 return failed;
377 }
378
379 int
main(void)380 main(void)
381 {
382 int failed = 0;
383
384 failed |= test_bn_mod_inverse();
385
386 return failed;
387 }
388