1 /*
2 * Copyright 1995-2025 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 /*
11 * NB: these functions have been "upgraded", the deprecated versions (which
12 * are compatibility wrappers using these functions) are in rsa_depr.c. -
13 * Geoff
14 */
15
16 /*
17 * RSA low level APIs are deprecated for public use, but still ok for
18 * internal use.
19 */
20 #include "internal/deprecated.h"
21
22 #include <stdio.h>
23 #include <time.h>
24 #include "internal/cryptlib.h"
25 #include <openssl/bn.h>
26 #include <openssl/self_test.h>
27 #include "prov/providercommon.h"
28 #include "rsa_local.h"
29
30 static int rsa_keygen_pairwise_test(RSA *rsa, OSSL_CALLBACK *cb, void *cbarg);
31 static int rsa_keygen(OSSL_LIB_CTX *libctx, RSA *rsa, int bits, int primes,
32 BIGNUM *e_value, BN_GENCB *cb, int pairwise_test);
33
34 /*
35 * NB: this wrapper would normally be placed in rsa_lib.c and the static
36 * implementation would probably be in rsa_eay.c. Nonetheless, is kept here
37 * so that we don't introduce a new linker dependency. Eg. any application
38 * that wasn't previously linking object code related to key-generation won't
39 * have to now just because key-generation is part of RSA_METHOD.
40 */
RSA_generate_key_ex(RSA * rsa,int bits,BIGNUM * e_value,BN_GENCB * cb)41 int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
42 {
43 if (rsa->meth->rsa_keygen != NULL)
44 return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
45
46 return RSA_generate_multi_prime_key(rsa, bits, RSA_DEFAULT_PRIME_NUM,
47 e_value, cb);
48 }
49
RSA_generate_multi_prime_key(RSA * rsa,int bits,int primes,BIGNUM * e_value,BN_GENCB * cb)50 int RSA_generate_multi_prime_key(RSA *rsa, int bits, int primes,
51 BIGNUM *e_value, BN_GENCB *cb)
52 {
53 #ifndef FIPS_MODULE
54 /* multi-prime is only supported with the builtin key generation */
55 if (rsa->meth->rsa_multi_prime_keygen != NULL) {
56 return rsa->meth->rsa_multi_prime_keygen(rsa, bits, primes,
57 e_value, cb);
58 } else if (rsa->meth->rsa_keygen != NULL) {
59 /*
60 * However, if rsa->meth implements only rsa_keygen, then we
61 * have to honour it in 2-prime case and assume that it wouldn't
62 * know what to do with multi-prime key generated by builtin
63 * subroutine...
64 */
65 if (primes == 2)
66 return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
67 else
68 return 0;
69 }
70 #endif /* FIPS_MODULE */
71 return rsa_keygen(rsa->libctx, rsa, bits, primes, e_value, cb, 0);
72 }
73
DEFINE_STACK_OF(BIGNUM)74 DEFINE_STACK_OF(BIGNUM)
75
76 /*
77 * Given input values, q, p, n, d and e, derive the exponents
78 * and coefficients for each prime in this key, placing the result
79 * on their respective exps and coeffs stacks
80 */
81 #ifndef FIPS_MODULE
82 int ossl_rsa_multiprime_derive(RSA *rsa, int bits, int primes,
83 BIGNUM *e_value,
84 STACK_OF(BIGNUM) *factors,
85 STACK_OF(BIGNUM) *exps,
86 STACK_OF(BIGNUM) *coeffs)
87 {
88 STACK_OF(BIGNUM) *pplist = NULL, *pdlist = NULL;
89 BIGNUM *factor = NULL, *newpp = NULL, *newpd = NULL;
90 BIGNUM *dval = NULL, *newexp = NULL, *newcoeff = NULL;
91 BIGNUM *p = NULL, *q = NULL;
92 BIGNUM *dmp1 = NULL, *dmq1 = NULL, *iqmp = NULL;
93 BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL;
94 BN_CTX *ctx = NULL;
95 BIGNUM *tmp = NULL;
96 int i;
97 int ret = 0;
98
99 ctx = BN_CTX_new_ex(rsa->libctx);
100 if (ctx == NULL)
101 goto err;
102
103 BN_CTX_start(ctx);
104
105 pplist = sk_BIGNUM_new_null();
106 if (pplist == NULL)
107 goto err;
108
109 pdlist = sk_BIGNUM_new_null();
110 if (pdlist == NULL)
111 goto err;
112
113 r0 = BN_CTX_get(ctx);
114 r1 = BN_CTX_get(ctx);
115 r2 = BN_CTX_get(ctx);
116
117 if (r2 == NULL)
118 goto err;
119
120 BN_set_flags(r0, BN_FLG_CONSTTIME);
121 BN_set_flags(r1, BN_FLG_CONSTTIME);
122 BN_set_flags(r2, BN_FLG_CONSTTIME);
123
124 if (BN_copy(r1, rsa->n) == NULL)
125 goto err;
126
127 p = sk_BIGNUM_value(factors, 0);
128 q = sk_BIGNUM_value(factors, 1);
129
130 /* Build list of partial products of primes */
131 for (i = 0; i < sk_BIGNUM_num(factors); i++) {
132 switch (i) {
133 case 0:
134 /* our first prime, p */
135 if (!BN_sub(r2, p, BN_value_one()))
136 goto err;
137 BN_set_flags(r2, BN_FLG_CONSTTIME);
138 if (BN_mod_inverse(r1, r2, rsa->e, ctx) == NULL)
139 goto err;
140 break;
141 case 1:
142 /* second prime q */
143 if (!BN_mul(r1, p, q, ctx))
144 goto err;
145 tmp = BN_dup(r1);
146 if (tmp == NULL)
147 goto err;
148 if (!sk_BIGNUM_insert(pplist, tmp, sk_BIGNUM_num(pplist)))
149 goto err;
150 tmp = NULL;
151 break;
152 default:
153 factor = sk_BIGNUM_value(factors, i);
154 /* all other primes */
155 if (!BN_mul(r1, r1, factor, ctx))
156 goto err;
157 tmp = BN_dup(r1);
158 if (tmp == NULL)
159 goto err;
160 if (!sk_BIGNUM_insert(pplist, tmp, sk_BIGNUM_num(pplist)))
161 goto err;
162 tmp = NULL;
163 break;
164 }
165 }
166
167 /* build list of relative d values */
168 /* p -1 */
169 if (!BN_sub(r1, p, BN_value_one()))
170 goto err;
171 if (!BN_sub(r2, q, BN_value_one()))
172 goto err;
173 if (!BN_mul(r0, r1, r2, ctx))
174 goto err;
175 for (i = 2; i < sk_BIGNUM_num(factors); i++) {
176 factor = sk_BIGNUM_value(factors, i);
177 dval = BN_new();
178 if (dval == NULL)
179 goto err;
180 BN_set_flags(dval, BN_FLG_CONSTTIME);
181 if (!BN_sub(dval, factor, BN_value_one()))
182 goto err;
183 if (!BN_mul(r0, r0, dval, ctx))
184 goto err;
185 if (!sk_BIGNUM_insert(pdlist, dval, sk_BIGNUM_num(pdlist)))
186 goto err;
187 dval = NULL;
188 }
189
190 /* Calculate dmp1, dmq1 and additional exponents */
191 dmp1 = BN_secure_new();
192 if (dmp1 == NULL)
193 goto err;
194 dmq1 = BN_secure_new();
195 if (dmq1 == NULL)
196 goto err;
197
198 if (!BN_mod(dmp1, rsa->d, r1, ctx))
199 goto err;
200 if (!sk_BIGNUM_insert(exps, dmp1, sk_BIGNUM_num(exps)))
201 goto err;
202 dmp1 = NULL;
203
204 if (!BN_mod(dmq1, rsa->d, r2, ctx))
205 goto err;
206 if (!sk_BIGNUM_insert(exps, dmq1, sk_BIGNUM_num(exps)))
207 goto err;
208 dmq1 = NULL;
209
210 for (i = 2; i < sk_BIGNUM_num(factors); i++) {
211 newpd = sk_BIGNUM_value(pdlist, i - 2);
212 newexp = BN_new();
213 if (newexp == NULL)
214 goto err;
215 if (!BN_mod(newexp, rsa->d, newpd, ctx))
216 goto err;
217 if (!sk_BIGNUM_insert(exps, newexp, sk_BIGNUM_num(exps)))
218 goto err;
219 newexp = NULL;
220 }
221
222 /* Calculate iqmp and additional coefficients */
223 iqmp = BN_new();
224 if (iqmp == NULL)
225 goto err;
226
227 if (BN_mod_inverse(iqmp, sk_BIGNUM_value(factors, 1),
228 sk_BIGNUM_value(factors, 0), ctx) == NULL)
229 goto err;
230 if (!sk_BIGNUM_insert(coeffs, iqmp, sk_BIGNUM_num(coeffs)))
231 goto err;
232 iqmp = NULL;
233
234 for (i = 2; i < sk_BIGNUM_num(factors); i++) {
235 newpp = sk_BIGNUM_value(pplist, i - 2);
236 newcoeff = BN_new();
237 if (newcoeff == NULL)
238 goto err;
239 if (BN_mod_inverse(newcoeff, newpp, sk_BIGNUM_value(factors, i),
240 ctx) == NULL)
241 goto err;
242 if (!sk_BIGNUM_insert(coeffs, newcoeff, sk_BIGNUM_num(coeffs)))
243 goto err;
244 newcoeff = NULL;
245 }
246
247 ret = 1;
248 err:
249 BN_free(newcoeff);
250 BN_free(newexp);
251 BN_free(dval);
252 BN_free(tmp);
253 sk_BIGNUM_pop_free(pplist, BN_free);
254 sk_BIGNUM_pop_free(pdlist, BN_free);
255 BN_CTX_end(ctx);
256 BN_CTX_free(ctx);
257 BN_clear_free(dmp1);
258 BN_clear_free(dmq1);
259 BN_clear_free(iqmp);
260 return ret;
261 }
262
rsa_multiprime_keygen(RSA * rsa,int bits,int primes,BIGNUM * e_value,BN_GENCB * cb)263 static int rsa_multiprime_keygen(RSA *rsa, int bits, int primes,
264 BIGNUM *e_value, BN_GENCB *cb)
265 {
266 BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *tmp, *tmp2, *prime;
267 int n = 0, bitsr[RSA_MAX_PRIME_NUM], bitse = 0;
268 int i = 0, quo = 0, rmd = 0, adj = 0, retries = 0;
269 RSA_PRIME_INFO *pinfo = NULL;
270 STACK_OF(RSA_PRIME_INFO) *prime_infos = NULL;
271 STACK_OF(BIGNUM) *factors = NULL;
272 STACK_OF(BIGNUM) *exps = NULL;
273 STACK_OF(BIGNUM) *coeffs = NULL;
274 BN_CTX *ctx = NULL;
275 BN_ULONG bitst = 0;
276 unsigned long error = 0;
277 int ok = -1;
278
279 if (bits < RSA_MIN_MODULUS_BITS) {
280 ERR_raise(ERR_LIB_RSA, RSA_R_KEY_SIZE_TOO_SMALL);
281 return 0;
282 }
283 if (e_value == NULL) {
284 ERR_raise(ERR_LIB_RSA, RSA_R_BAD_E_VALUE);
285 return 0;
286 }
287 /* A bad value for e can cause infinite loops */
288 if (!ossl_rsa_check_public_exponent(e_value)) {
289 ERR_raise(ERR_LIB_RSA, RSA_R_PUB_EXPONENT_OUT_OF_RANGE);
290 return 0;
291 }
292
293 if (primes < RSA_DEFAULT_PRIME_NUM || primes > ossl_rsa_multip_cap(bits)) {
294 ERR_raise(ERR_LIB_RSA, RSA_R_KEY_PRIME_NUM_INVALID);
295 return 0;
296 }
297
298 factors = sk_BIGNUM_new_null();
299 if (factors == NULL)
300 return 0;
301
302 exps = sk_BIGNUM_new_null();
303 if (exps == NULL)
304 goto err;
305
306 coeffs = sk_BIGNUM_new_null();
307 if (coeffs == NULL)
308 goto err;
309
310 ctx = BN_CTX_new_ex(rsa->libctx);
311 if (ctx == NULL)
312 goto err;
313 BN_CTX_start(ctx);
314 r0 = BN_CTX_get(ctx);
315 r1 = BN_CTX_get(ctx);
316 r2 = BN_CTX_get(ctx);
317 if (r2 == NULL)
318 goto err;
319
320 /* divide bits into 'primes' pieces evenly */
321 quo = bits / primes;
322 rmd = bits % primes;
323
324 for (i = 0; i < primes; i++)
325 bitsr[i] = (i < rmd) ? quo + 1 : quo;
326
327 rsa->dirty_cnt++;
328
329 /* We need the RSA components non-NULL */
330 if (!rsa->n && ((rsa->n = BN_new()) == NULL))
331 goto err;
332 if (!rsa->d && ((rsa->d = BN_secure_new()) == NULL))
333 goto err;
334 BN_set_flags(rsa->d, BN_FLG_CONSTTIME);
335 if (!rsa->e && ((rsa->e = BN_new()) == NULL))
336 goto err;
337 if (!rsa->p && ((rsa->p = BN_secure_new()) == NULL))
338 goto err;
339 BN_set_flags(rsa->p, BN_FLG_CONSTTIME);
340 if (!rsa->q && ((rsa->q = BN_secure_new()) == NULL))
341 goto err;
342 BN_set_flags(rsa->q, BN_FLG_CONSTTIME);
343
344 /* initialize multi-prime components */
345 if (primes > RSA_DEFAULT_PRIME_NUM) {
346 rsa->version = RSA_ASN1_VERSION_MULTI;
347 prime_infos = sk_RSA_PRIME_INFO_new_reserve(NULL, primes - 2);
348 if (prime_infos == NULL)
349 goto err;
350 if (rsa->prime_infos != NULL) {
351 /* could this happen? */
352 sk_RSA_PRIME_INFO_pop_free(rsa->prime_infos,
353 ossl_rsa_multip_info_free);
354 }
355 rsa->prime_infos = prime_infos;
356
357 /* prime_info from 2 to |primes| -1 */
358 for (i = 2; i < primes; i++) {
359 pinfo = ossl_rsa_multip_info_new();
360 if (pinfo == NULL)
361 goto err;
362 (void)sk_RSA_PRIME_INFO_push(prime_infos, pinfo);
363 }
364 }
365
366 if (BN_copy(rsa->e, e_value) == NULL)
367 goto err;
368
369 /* generate p, q and other primes (if any) */
370 for (i = 0; i < primes; i++) {
371 adj = 0;
372 retries = 0;
373
374 if (i == 0) {
375 prime = rsa->p;
376 } else if (i == 1) {
377 prime = rsa->q;
378 } else {
379 pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2);
380 prime = pinfo->r;
381 }
382 BN_set_flags(prime, BN_FLG_CONSTTIME);
383
384 for (;;) {
385 redo:
386 if (!BN_generate_prime_ex2(prime, bitsr[i] + adj, 0, NULL, NULL,
387 cb, ctx))
388 goto err;
389 /*
390 * prime should not be equal to p, q, r_3...
391 * (those primes prior to this one)
392 */
393 {
394 int j;
395
396 for (j = 0; j < i; j++) {
397 BIGNUM *prev_prime;
398
399 if (j == 0)
400 prev_prime = rsa->p;
401 else if (j == 1)
402 prev_prime = rsa->q;
403 else
404 prev_prime = sk_RSA_PRIME_INFO_value(prime_infos,
405 j - 2)->r;
406
407 if (!BN_cmp(prime, prev_prime)) {
408 goto redo;
409 }
410 }
411 }
412 if (!BN_sub(r2, prime, BN_value_one()))
413 goto err;
414 ERR_set_mark();
415 BN_set_flags(r2, BN_FLG_CONSTTIME);
416 if (BN_mod_inverse(r1, r2, rsa->e, ctx) != NULL) {
417 /* GCD == 1 since inverse exists */
418 break;
419 }
420 error = ERR_peek_last_error();
421 if (ERR_GET_LIB(error) == ERR_LIB_BN
422 && ERR_GET_REASON(error) == BN_R_NO_INVERSE) {
423 /* GCD != 1 */
424 ERR_pop_to_mark();
425 } else {
426 goto err;
427 }
428 if (!BN_GENCB_call(cb, 2, n++))
429 goto err;
430 }
431
432 bitse += bitsr[i];
433
434 /* calculate n immediately to see if it's sufficient */
435 if (i == 1) {
436 /* we get at least 2 primes */
437 if (!BN_mul(r1, rsa->p, rsa->q, ctx))
438 goto err;
439 } else if (i != 0) {
440 /* modulus n = p * q * r_3 * r_4 ... */
441 if (!BN_mul(r1, rsa->n, prime, ctx))
442 goto err;
443 } else {
444 /* i == 0, do nothing */
445 if (!BN_GENCB_call(cb, 3, i))
446 goto err;
447 tmp = BN_dup(prime);
448 if (tmp == NULL)
449 goto err;
450 if (!sk_BIGNUM_insert(factors, tmp, sk_BIGNUM_num(factors)))
451 goto err;
452 continue;
453 }
454
455 /*
456 * if |r1|, product of factors so far, is not as long as expected
457 * (by checking the first 4 bits are less than 0x9 or greater than
458 * 0xF). If so, re-generate the last prime.
459 *
460 * NOTE: This actually can't happen in two-prime case, because of
461 * the way factors are generated.
462 *
463 * Besides, another consideration is, for multi-prime case, even the
464 * length modulus is as long as expected, the modulus could start at
465 * 0x8, which could be utilized to distinguish a multi-prime private
466 * key by using the modulus in a certificate. This is also covered
467 * by checking the length should not be less than 0x9.
468 */
469 if (!BN_rshift(r2, r1, bitse - 4))
470 goto err;
471 bitst = BN_get_word(r2);
472
473 if (bitst < 0x9 || bitst > 0xF) {
474 /*
475 * For keys with more than 4 primes, we attempt longer factor to
476 * meet length requirement.
477 *
478 * Otherwise, we just re-generate the prime with the same length.
479 *
480 * This strategy has the following goals:
481 *
482 * 1. 1024-bit factors are efficient when using 3072 and 4096-bit key
483 * 2. stay the same logic with normal 2-prime key
484 */
485 bitse -= bitsr[i];
486 if (!BN_GENCB_call(cb, 2, n++))
487 goto err;
488 if (primes > 4) {
489 if (bitst < 0x9)
490 adj++;
491 else
492 adj--;
493 } else if (retries == 4) {
494 /*
495 * re-generate all primes from scratch, mainly used
496 * in 4 prime case to avoid long loop. Max retry times
497 * is set to 4.
498 */
499 i = -1;
500 bitse = 0;
501 sk_BIGNUM_pop_free(factors, BN_clear_free);
502 factors = sk_BIGNUM_new_null();
503 if (factors == NULL)
504 goto err;
505 continue;
506 }
507 retries++;
508 goto redo;
509 }
510 /* save product of primes for further use, for multi-prime only */
511 if (i > 1 && BN_copy(pinfo->pp, rsa->n) == NULL)
512 goto err;
513 if (BN_copy(rsa->n, r1) == NULL)
514 goto err;
515 if (!BN_GENCB_call(cb, 3, i))
516 goto err;
517 tmp = BN_dup(prime);
518 if (tmp == NULL)
519 goto err;
520 if (!sk_BIGNUM_insert(factors, tmp, sk_BIGNUM_num(factors)))
521 goto err;
522 }
523
524 if (BN_cmp(rsa->p, rsa->q) < 0) {
525 tmp = rsa->p;
526 rsa->p = rsa->q;
527 rsa->q = tmp;
528 /* mirror this in our factor stack */
529 if (!sk_BIGNUM_insert(factors, sk_BIGNUM_delete(factors, 0), 1))
530 goto err;
531 }
532
533 /* calculate d */
534
535 /* p - 1 */
536 if (!BN_sub(r1, rsa->p, BN_value_one()))
537 goto err;
538 /* q - 1 */
539 if (!BN_sub(r2, rsa->q, BN_value_one()))
540 goto err;
541 /* (p - 1)(q - 1) */
542 if (!BN_mul(r0, r1, r2, ctx))
543 goto err;
544 /* multi-prime */
545 for (i = 2; i < primes; i++) {
546 pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2);
547 /* save r_i - 1 to pinfo->d temporarily */
548 if (!BN_sub(pinfo->d, pinfo->r, BN_value_one()))
549 goto err;
550 if (!BN_mul(r0, r0, pinfo->d, ctx))
551 goto err;
552 }
553
554
555 BN_set_flags(r0, BN_FLG_CONSTTIME);
556 if (BN_mod_inverse(rsa->d, rsa->e, r0, ctx) == NULL) {
557 goto err; /* d */
558 }
559
560 /* derive any missing exponents and coefficients */
561 if (!ossl_rsa_multiprime_derive(rsa, bits, primes, e_value,
562 factors, exps, coeffs))
563 goto err;
564
565 /*
566 * first 2 factors/exps are already tracked in p/q/dmq1/dmp1
567 * and the first coeff is in iqmp, so pop those off the stack
568 * Note, the first 2 factors/exponents are already tracked by p and q
569 * assign dmp1/dmq1 and iqmp
570 * the remaining pinfo values are separately allocated, so copy and delete
571 * those
572 */
573 BN_clear_free(sk_BIGNUM_delete(factors, 0));
574 BN_clear_free(sk_BIGNUM_delete(factors, 0));
575 rsa->dmp1 = sk_BIGNUM_delete(exps, 0);
576 rsa->dmq1 = sk_BIGNUM_delete(exps, 0);
577 rsa->iqmp = sk_BIGNUM_delete(coeffs, 0);
578 for (i = 2; i < primes; i++) {
579 pinfo = sk_RSA_PRIME_INFO_value(prime_infos, i - 2);
580 tmp = sk_BIGNUM_delete(factors, 0);
581 BN_copy(pinfo->r, tmp);
582 BN_clear_free(tmp);
583 tmp = sk_BIGNUM_delete(exps, 0);
584 tmp2 = BN_copy(pinfo->d, tmp);
585 BN_clear_free(tmp);
586 if (tmp2 == NULL)
587 goto err;
588 tmp = sk_BIGNUM_delete(coeffs, 0);
589 tmp2 = BN_copy(pinfo->t, tmp);
590 BN_clear_free(tmp);
591 if (tmp2 == NULL)
592 goto err;
593 }
594 ok = 1;
595 err:
596 sk_BIGNUM_free(factors);
597 sk_BIGNUM_free(exps);
598 sk_BIGNUM_free(coeffs);
599 if (ok == -1) {
600 ERR_raise(ERR_LIB_RSA, ERR_R_BN_LIB);
601 ok = 0;
602 }
603 BN_CTX_end(ctx);
604 BN_CTX_free(ctx);
605 return ok;
606 }
607 #endif /* FIPS_MODULE */
608
rsa_keygen(OSSL_LIB_CTX * libctx,RSA * rsa,int bits,int primes,BIGNUM * e_value,BN_GENCB * cb,int pairwise_test)609 static int rsa_keygen(OSSL_LIB_CTX *libctx, RSA *rsa, int bits, int primes,
610 BIGNUM *e_value, BN_GENCB *cb, int pairwise_test)
611 {
612 int ok = 0;
613
614 #ifdef FIPS_MODULE
615 ok = ossl_rsa_sp800_56b_generate_key(rsa, bits, e_value, cb);
616 pairwise_test = 1; /* FIPS MODE needs to always run the pairwise test */
617 #else
618 /*
619 * Only multi-prime keys or insecure keys with a small key length or a
620 * public exponent <= 2^16 will use the older rsa_multiprime_keygen().
621 */
622 if (primes == 2
623 && bits >= 2048
624 && (e_value == NULL || BN_num_bits(e_value) > 16))
625 ok = ossl_rsa_sp800_56b_generate_key(rsa, bits, e_value, cb);
626 else
627 ok = rsa_multiprime_keygen(rsa, bits, primes, e_value, cb);
628 #endif /* FIPS_MODULE */
629
630 if (pairwise_test && ok > 0) {
631 OSSL_CALLBACK *stcb = NULL;
632 void *stcbarg = NULL;
633
634 OSSL_SELF_TEST_get_callback(libctx, &stcb, &stcbarg);
635 ok = rsa_keygen_pairwise_test(rsa, stcb, stcbarg);
636 if (!ok) {
637 ossl_set_error_state(OSSL_SELF_TEST_TYPE_PCT);
638 /* Clear intermediate results */
639 BN_clear_free(rsa->d);
640 BN_clear_free(rsa->p);
641 BN_clear_free(rsa->q);
642 BN_clear_free(rsa->dmp1);
643 BN_clear_free(rsa->dmq1);
644 BN_clear_free(rsa->iqmp);
645 rsa->d = NULL;
646 rsa->p = NULL;
647 rsa->q = NULL;
648 rsa->dmp1 = NULL;
649 rsa->dmq1 = NULL;
650 rsa->iqmp = NULL;
651 }
652 }
653 return ok;
654 }
655
656 /*
657 * AS10.35 (and its VEs/TEs) of the FIPS 140-3 standard requires a PCT for every
658 * generated key pair. There are 3 options:
659 * 1) If the key pair is to be used for key transport (asymmetric cipher), the
660 * PCT consists of encrypting a plaintext, verifying that the result
661 * (ciphertext) is not equal to the plaintext, decrypting the ciphertext, and
662 * verifying that the result is equal to the plaintext.
663 * 2) If the key pair is to be used for digital signatures, the PCT consists of
664 * computing and verifying a signature.
665 * 3) If the key pair is to be used for key agreement, the exact PCT is defined
666 * in the applicable standards. For RSA-based schemes, this is defined in
667 * SP 800-56Br2 (Section 6.4.1.1) as:
668 * "The owner shall perform a pair-wise consistency test by verifying that m
669 * = (m^e)^d mod n for some integer m satisfying 1 < m < (n - 1)."
670 *
671 * OpenSSL implements all three use cases: RSA-OAEP for key transport,
672 * RSA signatures with PKCS#1 v1.5 or PSS padding, and KAS-IFC-SSC (KAS1/KAS2)
673 * using RSASVE.
674 *
675 * According to FIPS 140-3 IG 10.3.A, if at the time when the PCT is performed
676 * the keys' intended usage is not known, then any of the three PCTs described
677 * in AS10.35 shall be performed on this key pair.
678 *
679 * Because of this allowance from the IG, the simplest option is 3, i.e.
680 * RSA_public_encrypt() and RSA_private_decrypt() with RSA_NO_PADDING.
681 */
rsa_keygen_pairwise_test(RSA * rsa,OSSL_CALLBACK * cb,void * cbarg)682 static int rsa_keygen_pairwise_test(RSA *rsa, OSSL_CALLBACK *cb, void *cbarg)
683 {
684 int ret = 0;
685 unsigned int plaintxt_len;
686 unsigned char *plaintxt = NULL;
687 unsigned int ciphertxt_len;
688 unsigned char *ciphertxt = NULL;
689 unsigned char *decoded = NULL;
690 unsigned int decoded_len;
691 int padding = RSA_NO_PADDING;
692 OSSL_SELF_TEST *st = NULL;
693
694 st = OSSL_SELF_TEST_new(cb, cbarg);
695 if (st == NULL)
696 goto err;
697 OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT,
698 OSSL_SELF_TEST_DESC_PCT_RSA);
699
700 /*
701 * For RSA_NO_PADDING, RSA_public_encrypt() and RSA_private_decrypt()
702 * require the 'to' and 'from' parameters to have equal length and a
703 * maximum of RSA_size() - allocate space for plaintxt, ciphertxt, and
704 * decoded.
705 */
706 plaintxt_len = RSA_size(rsa);
707 plaintxt = OPENSSL_zalloc(plaintxt_len * 3);
708 if (plaintxt == NULL)
709 goto err;
710 ciphertxt = plaintxt + plaintxt_len;
711 decoded = ciphertxt + plaintxt_len;
712
713 /* SP 800-56Br2 Section 6.4.1.1 requires that plaintext is greater than 1 */
714 plaintxt[plaintxt_len - 1] = 2;
715
716 ciphertxt_len = RSA_public_encrypt(plaintxt_len, plaintxt, ciphertxt, rsa,
717 padding);
718 if (ciphertxt_len <= 0)
719 goto err;
720
721 OSSL_SELF_TEST_oncorrupt_byte(st, ciphertxt);
722
723 decoded_len = RSA_private_decrypt(ciphertxt_len, ciphertxt, decoded, rsa,
724 padding);
725 if (decoded_len != plaintxt_len
726 || memcmp(decoded, plaintxt, decoded_len) != 0)
727 goto err;
728
729 ret = 1;
730 err:
731 OSSL_SELF_TEST_onend(st, ret);
732 OSSL_SELF_TEST_free(st);
733 OPENSSL_free(plaintxt);
734
735 return ret;
736 }
737