1 /*
2  * Copyright 2020-2023 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 /*
11  * RSA low level APIs are deprecated for public use, but still ok for
12  * internal use.
13  */
14 #include "internal/deprecated.h"
15 
16 #include <string.h>
17 #include <openssl/core_names.h>
18 #include <openssl/params.h>
19 #include <openssl/err.h>
20 #include <openssl/evp.h>
21 #ifndef FIPS_MODULE
22 # include <openssl/x509.h>
23 # include "crypto/asn1.h"
24 #endif
25 #include "internal/sizes.h"
26 #include "internal/param_build_set.h"
27 #include "crypto/rsa.h"
28 #include "rsa_local.h"
29 
30 /*
31  * The intention with the "backend" source file is to offer backend support
32  * for legacy backends (EVP_PKEY_ASN1_METHOD and EVP_PKEY_METHOD) and provider
33  * implementations alike.
34  */
35 
36 DEFINE_STACK_OF(BIGNUM)
37 
38 static int collect_numbers(STACK_OF(BIGNUM) *numbers,
39                            const OSSL_PARAM params[], const char *names[])
40 {
41     const OSSL_PARAM *p = NULL;
42     int i;
43 
44     if (numbers == NULL)
45         return 0;
46 
47     for (i = 0; names[i] != NULL; i++){
48         p = OSSL_PARAM_locate_const(params, names[i]);
49         if (p != NULL) {
50             BIGNUM *tmp = NULL;
51 
52             if (!OSSL_PARAM_get_BN(p, &tmp))
53                 return 0;
54             if (sk_BIGNUM_push(numbers, tmp) == 0) {
55                 BN_clear_free(tmp);
56                 return 0;
57             }
58         }
59     }
60 
61     return 1;
62 }
63 
64 int ossl_rsa_fromdata(RSA *rsa, const OSSL_PARAM params[], int include_private)
65 {
66     const OSSL_PARAM *param_n, *param_e,  *param_d = NULL;
67     BIGNUM *n = NULL, *e = NULL, *d = NULL;
68     STACK_OF(BIGNUM) *factors = NULL, *exps = NULL, *coeffs = NULL;
69     int is_private = 0;
70 
71     if (rsa == NULL)
72         return 0;
73 
74     param_n = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_RSA_N);
75     param_e = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_RSA_E);
76     if (include_private)
77         param_d = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_RSA_D);
78 
79     if ((param_n != NULL && !OSSL_PARAM_get_BN(param_n, &n))
80         || (param_e != NULL && !OSSL_PARAM_get_BN(param_e, &e))
81         || (param_d != NULL && !OSSL_PARAM_get_BN(param_d, &d)))
82         goto err;
83 
84     is_private = (d != NULL);
85 
86     if (!RSA_set0_key(rsa, n, e, d))
87         goto err;
88     n = e = d = NULL;
89 
90     if (is_private) {
91         if (!collect_numbers(factors = sk_BIGNUM_new_null(), params,
92                              ossl_rsa_mp_factor_names)
93             || !collect_numbers(exps = sk_BIGNUM_new_null(), params,
94                                 ossl_rsa_mp_exp_names)
95             || !collect_numbers(coeffs = sk_BIGNUM_new_null(), params,
96                                 ossl_rsa_mp_coeff_names))
97             goto err;
98 
99         /* It's ok if this private key just has n, e and d */
100         if (sk_BIGNUM_num(factors) != 0
101             && !ossl_rsa_set0_all_params(rsa, factors, exps, coeffs))
102             goto err;
103     }
104 
105 
106     sk_BIGNUM_free(factors);
107     sk_BIGNUM_free(exps);
108     sk_BIGNUM_free(coeffs);
109     return 1;
110 
111  err:
112     BN_free(n);
113     BN_free(e);
114     BN_free(d);
115     sk_BIGNUM_pop_free(factors, BN_free);
116     sk_BIGNUM_pop_free(exps, BN_free);
117     sk_BIGNUM_pop_free(coeffs, BN_free);
118     return 0;
119 }
120 
121 DEFINE_SPECIAL_STACK_OF_CONST(BIGNUM_const, BIGNUM)
122 
123 int ossl_rsa_todata(RSA *rsa, OSSL_PARAM_BLD *bld, OSSL_PARAM params[],
124                     int include_private)
125 {
126     int ret = 0;
127     const BIGNUM *rsa_d = NULL, *rsa_n = NULL, *rsa_e = NULL;
128     STACK_OF(BIGNUM_const) *factors = sk_BIGNUM_const_new_null();
129     STACK_OF(BIGNUM_const) *exps = sk_BIGNUM_const_new_null();
130     STACK_OF(BIGNUM_const) *coeffs = sk_BIGNUM_const_new_null();
131 
132     if (rsa == NULL || factors == NULL || exps == NULL || coeffs == NULL)
133         goto err;
134 
135     RSA_get0_key(rsa, &rsa_n, &rsa_e, &rsa_d);
136     ossl_rsa_get0_all_params(rsa, factors, exps, coeffs);
137 
138     if (!ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_RSA_N, rsa_n)
139         || !ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_RSA_E, rsa_e))
140         goto err;
141 
142     /* Check private key data integrity */
143     if (include_private && rsa_d != NULL) {
144 
145         if (!ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_RSA_D,
146                                      rsa_d)
147             || !ossl_param_build_set_multi_key_bn(bld, params,
148                                                   ossl_rsa_mp_factor_names,
149                                                   factors)
150             || !ossl_param_build_set_multi_key_bn(bld, params,
151                                                   ossl_rsa_mp_exp_names, exps)
152             || !ossl_param_build_set_multi_key_bn(bld, params,
153                                                   ossl_rsa_mp_coeff_names,
154                                                   coeffs))
155         goto err;
156     }
157 
158 #if defined(FIPS_MODULE) && !defined(OPENSSL_NO_ACVP_TESTS)
159     /* The acvp test results are not meant for export so check for bld == NULL */
160     if (bld == NULL)
161         ossl_rsa_acvp_test_get_params(rsa, params);
162 #endif
163     ret = 1;
164  err:
165     sk_BIGNUM_const_free(factors);
166     sk_BIGNUM_const_free(exps);
167     sk_BIGNUM_const_free(coeffs);
168     return ret;
169 }
170 
171 int ossl_rsa_pss_params_30_todata(const RSA_PSS_PARAMS_30 *pss,
172                                   OSSL_PARAM_BLD *bld, OSSL_PARAM params[])
173 {
174     if (!ossl_rsa_pss_params_30_is_unrestricted(pss)) {
175         int hashalg_nid = ossl_rsa_pss_params_30_hashalg(pss);
176         int maskgenalg_nid = ossl_rsa_pss_params_30_maskgenalg(pss);
177         int maskgenhashalg_nid = ossl_rsa_pss_params_30_maskgenhashalg(pss);
178         int saltlen = ossl_rsa_pss_params_30_saltlen(pss);
179         int default_hashalg_nid = ossl_rsa_pss_params_30_hashalg(NULL);
180         int default_maskgenalg_nid = ossl_rsa_pss_params_30_maskgenalg(NULL);
181         int default_maskgenhashalg_nid =
182                 ossl_rsa_pss_params_30_maskgenhashalg(NULL);
183         const char *mdname =
184             (hashalg_nid == default_hashalg_nid
185              ? NULL : ossl_rsa_oaeppss_nid2name(hashalg_nid));
186         const char *mgfname =
187             (maskgenalg_nid == default_maskgenalg_nid
188              ? NULL : ossl_rsa_oaeppss_nid2name(maskgenalg_nid));
189         const char *mgf1mdname =
190             (maskgenhashalg_nid == default_maskgenhashalg_nid
191              ? NULL : ossl_rsa_oaeppss_nid2name(maskgenhashalg_nid));
192         const char *key_md = OSSL_PKEY_PARAM_RSA_DIGEST;
193         const char *key_mgf = OSSL_PKEY_PARAM_RSA_MASKGENFUNC;
194         const char *key_mgf1_md = OSSL_PKEY_PARAM_RSA_MGF1_DIGEST;
195         const char *key_saltlen = OSSL_PKEY_PARAM_RSA_PSS_SALTLEN;
196 
197         /*
198          * To ensure that the key isn't seen as unrestricted by the recipient,
199          * we make sure that at least one PSS-related parameter is passed, even
200          * if it has a default value; saltlen.
201          */
202         if ((mdname != NULL
203              && !ossl_param_build_set_utf8_string(bld, params, key_md, mdname))
204             || (mgfname != NULL
205                 && !ossl_param_build_set_utf8_string(bld, params,
206                                                      key_mgf, mgfname))
207             || (mgf1mdname != NULL
208                 && !ossl_param_build_set_utf8_string(bld, params,
209                                                      key_mgf1_md, mgf1mdname))
210             || (!ossl_param_build_set_int(bld, params, key_saltlen, saltlen)))
211             return 0;
212     }
213     return 1;
214 }
215 
216 int ossl_rsa_pss_params_30_fromdata(RSA_PSS_PARAMS_30 *pss_params,
217                                     int *defaults_set,
218                                     const OSSL_PARAM params[],
219                                     OSSL_LIB_CTX *libctx)
220 {
221     const OSSL_PARAM *param_md, *param_mgf, *param_mgf1md,  *param_saltlen;
222     const OSSL_PARAM *param_propq;
223     const char *propq = NULL;
224     EVP_MD *md = NULL, *mgf1md = NULL;
225     int saltlen;
226     int ret = 0;
227 
228     if (pss_params == NULL)
229         return 0;
230     param_propq =
231         OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_RSA_DIGEST_PROPS);
232     param_md =
233         OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_RSA_DIGEST);
234     param_mgf =
235         OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_RSA_MASKGENFUNC);
236     param_mgf1md =
237         OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_RSA_MGF1_DIGEST);
238     param_saltlen =
239         OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_RSA_PSS_SALTLEN);
240 
241     if (param_propq != NULL) {
242         if (param_propq->data_type == OSSL_PARAM_UTF8_STRING)
243             propq = param_propq->data;
244     }
245     /*
246      * If we get any of the parameters, we know we have at least some
247      * restrictions, so we start by setting default values, and let each
248      * parameter override their specific restriction data.
249      */
250     if (!*defaults_set
251         && (param_md != NULL || param_mgf != NULL || param_mgf1md != NULL
252             || param_saltlen != NULL)) {
253         if (!ossl_rsa_pss_params_30_set_defaults(pss_params))
254             return 0;
255         *defaults_set = 1;
256     }
257 
258     if (param_mgf != NULL) {
259         int default_maskgenalg_nid = ossl_rsa_pss_params_30_maskgenalg(NULL);
260         const char *mgfname = NULL;
261 
262         if (param_mgf->data_type == OSSL_PARAM_UTF8_STRING)
263             mgfname = param_mgf->data;
264         else if (!OSSL_PARAM_get_utf8_ptr(param_mgf, &mgfname))
265             return 0;
266 
267         if (OPENSSL_strcasecmp(param_mgf->data,
268                                ossl_rsa_mgf_nid2name(default_maskgenalg_nid)) != 0)
269             return 0;
270     }
271 
272     /*
273      * We're only interested in the NIDs that correspond to the MDs, so the
274      * exact propquery is unimportant in the EVP_MD_fetch() calls below.
275      */
276 
277     if (param_md != NULL) {
278         const char *mdname = NULL;
279 
280         if (param_md->data_type == OSSL_PARAM_UTF8_STRING)
281             mdname = param_md->data;
282         else if (!OSSL_PARAM_get_utf8_ptr(param_mgf, &mdname))
283             goto err;
284 
285         if ((md = EVP_MD_fetch(libctx, mdname, propq)) == NULL
286             || !ossl_rsa_pss_params_30_set_hashalg(pss_params,
287                                                    ossl_rsa_oaeppss_md2nid(md)))
288             goto err;
289     }
290 
291     if (param_mgf1md != NULL) {
292         const char *mgf1mdname = NULL;
293 
294         if (param_mgf1md->data_type == OSSL_PARAM_UTF8_STRING)
295             mgf1mdname = param_mgf1md->data;
296         else if (!OSSL_PARAM_get_utf8_ptr(param_mgf, &mgf1mdname))
297             goto err;
298 
299         if ((mgf1md = EVP_MD_fetch(libctx, mgf1mdname, propq)) == NULL
300             || !ossl_rsa_pss_params_30_set_maskgenhashalg(
301                     pss_params, ossl_rsa_oaeppss_md2nid(mgf1md)))
302             goto err;
303     }
304 
305     if (param_saltlen != NULL) {
306         if (!OSSL_PARAM_get_int(param_saltlen, &saltlen)
307             || !ossl_rsa_pss_params_30_set_saltlen(pss_params, saltlen))
308             goto err;
309     }
310 
311     ret = 1;
312 
313  err:
314     EVP_MD_free(md);
315     EVP_MD_free(mgf1md);
316     return ret;
317 }
318 
319 int ossl_rsa_is_foreign(const RSA *rsa)
320 {
321 #ifndef FIPS_MODULE
322     if (rsa->engine != NULL || RSA_get_method(rsa) != RSA_PKCS1_OpenSSL())
323         return 1;
324 #endif
325     return 0;
326 }
327 
328 static ossl_inline int rsa_bn_dup_check(BIGNUM **out, const BIGNUM *f)
329 {
330     if (f != NULL && (*out = BN_dup(f)) == NULL)
331         return 0;
332     return 1;
333 }
334 
335 RSA *ossl_rsa_dup(const RSA *rsa, int selection)
336 {
337     RSA *dupkey = NULL;
338 #ifndef FIPS_MODULE
339     int pnum, i;
340 #endif
341 
342     /* Do not try to duplicate foreign RSA keys */
343     if (ossl_rsa_is_foreign(rsa))
344         return NULL;
345 
346     if ((dupkey = ossl_rsa_new_with_ctx(rsa->libctx)) == NULL)
347         return NULL;
348 
349     /* public key */
350     if ((selection & OSSL_KEYMGMT_SELECT_KEYPAIR) != 0) {
351         if (!rsa_bn_dup_check(&dupkey->n, rsa->n))
352             goto err;
353         if (!rsa_bn_dup_check(&dupkey->e, rsa->e))
354             goto err;
355     }
356 
357     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0) {
358 
359         /* private key */
360         if (!rsa_bn_dup_check(&dupkey->d, rsa->d))
361             goto err;
362 
363         /* factors and crt params */
364         if (!rsa_bn_dup_check(&dupkey->p, rsa->p))
365             goto err;
366         if (!rsa_bn_dup_check(&dupkey->q, rsa->q))
367             goto err;
368         if (!rsa_bn_dup_check(&dupkey->dmp1, rsa->dmp1))
369             goto err;
370         if (!rsa_bn_dup_check(&dupkey->dmq1, rsa->dmq1))
371             goto err;
372         if (!rsa_bn_dup_check(&dupkey->iqmp, rsa->iqmp))
373             goto err;
374     }
375 
376     dupkey->version = rsa->version;
377     dupkey->flags = rsa->flags;
378     /* we always copy the PSS parameters regardless of selection */
379     dupkey->pss_params = rsa->pss_params;
380 
381 #ifndef FIPS_MODULE
382     /* multiprime */
383     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
384         && (pnum = sk_RSA_PRIME_INFO_num(rsa->prime_infos)) > 0) {
385         dupkey->prime_infos = sk_RSA_PRIME_INFO_new_reserve(NULL, pnum);
386         if (dupkey->prime_infos == NULL)
387             goto err;
388         for (i = 0; i < pnum; i++) {
389             const RSA_PRIME_INFO *pinfo = NULL;
390             RSA_PRIME_INFO *duppinfo = NULL;
391 
392             if ((duppinfo = OPENSSL_zalloc(sizeof(*duppinfo))) == NULL) {
393                 ERR_raise(ERR_LIB_RSA, ERR_R_MALLOC_FAILURE);
394                 goto err;
395             }
396             /* push first so cleanup in error case works */
397             (void)sk_RSA_PRIME_INFO_push(dupkey->prime_infos, duppinfo);
398 
399             pinfo = sk_RSA_PRIME_INFO_value(rsa->prime_infos, i);
400             if (!rsa_bn_dup_check(&duppinfo->r, pinfo->r))
401                 goto err;
402             if (!rsa_bn_dup_check(&duppinfo->d, pinfo->d))
403                 goto err;
404             if (!rsa_bn_dup_check(&duppinfo->t, pinfo->t))
405                 goto err;
406         }
407         if (!ossl_rsa_multip_calc_product(dupkey))
408             goto err;
409     }
410 
411     if (rsa->pss != NULL) {
412         dupkey->pss = RSA_PSS_PARAMS_dup(rsa->pss);
413         if (rsa->pss->maskGenAlgorithm != NULL
414             && dupkey->pss->maskGenAlgorithm == NULL) {
415             dupkey->pss->maskHash = ossl_x509_algor_mgf1_decode(rsa->pss->maskGenAlgorithm);
416             if (dupkey->pss->maskHash == NULL)
417                 goto err;
418         }
419     }
420     if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_RSA,
421                             &dupkey->ex_data, &rsa->ex_data))
422         goto err;
423 #endif
424 
425     return dupkey;
426 
427  err:
428     RSA_free(dupkey);
429     return NULL;
430 }
431 
432 #ifndef FIPS_MODULE
433 RSA_PSS_PARAMS *ossl_rsa_pss_decode(const X509_ALGOR *alg)
434 {
435     RSA_PSS_PARAMS *pss;
436 
437     pss = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(RSA_PSS_PARAMS),
438                                     alg->parameter);
439 
440     if (pss == NULL)
441         return NULL;
442 
443     if (pss->maskGenAlgorithm != NULL) {
444         pss->maskHash = ossl_x509_algor_mgf1_decode(pss->maskGenAlgorithm);
445         if (pss->maskHash == NULL) {
446             RSA_PSS_PARAMS_free(pss);
447             return NULL;
448         }
449     }
450 
451     return pss;
452 }
453 
454 static int ossl_rsa_sync_to_pss_params_30(RSA *rsa)
455 {
456     const RSA_PSS_PARAMS *legacy_pss = NULL;
457     RSA_PSS_PARAMS_30 *pss = NULL;
458 
459     if (rsa != NULL
460         && (legacy_pss = RSA_get0_pss_params(rsa)) != NULL
461         && (pss = ossl_rsa_get0_pss_params_30(rsa)) != NULL) {
462         const EVP_MD *md = NULL, *mgf1md = NULL;
463         int md_nid, mgf1md_nid, saltlen, trailerField;
464         RSA_PSS_PARAMS_30 pss_params;
465 
466         /*
467          * We don't care about the validity of the fields here, we just
468          * want to synchronise values.  Verifying here makes it impossible
469          * to even read a key with invalid values, making it hard to test
470          * a bad situation.
471          *
472          * Other routines use ossl_rsa_pss_get_param(), so the values will
473          * be checked, eventually.
474          */
475         if (!ossl_rsa_pss_get_param_unverified(legacy_pss, &md, &mgf1md,
476                                                &saltlen, &trailerField))
477             return 0;
478         md_nid = EVP_MD_get_type(md);
479         mgf1md_nid = EVP_MD_get_type(mgf1md);
480         if (!ossl_rsa_pss_params_30_set_defaults(&pss_params)
481             || !ossl_rsa_pss_params_30_set_hashalg(&pss_params, md_nid)
482             || !ossl_rsa_pss_params_30_set_maskgenhashalg(&pss_params,
483                                                           mgf1md_nid)
484             || !ossl_rsa_pss_params_30_set_saltlen(&pss_params, saltlen)
485             || !ossl_rsa_pss_params_30_set_trailerfield(&pss_params,
486                                                         trailerField))
487             return 0;
488         *pss = pss_params;
489     }
490     return 1;
491 }
492 
493 int ossl_rsa_pss_get_param_unverified(const RSA_PSS_PARAMS *pss,
494                                       const EVP_MD **pmd, const EVP_MD **pmgf1md,
495                                       int *psaltlen, int *ptrailerField)
496 {
497     RSA_PSS_PARAMS_30 pss_params;
498 
499     /* Get the defaults from the ONE place */
500     (void)ossl_rsa_pss_params_30_set_defaults(&pss_params);
501 
502     if (pss == NULL)
503         return 0;
504     *pmd = ossl_x509_algor_get_md(pss->hashAlgorithm);
505     if (*pmd == NULL)
506         return 0;
507     *pmgf1md = ossl_x509_algor_get_md(pss->maskHash);
508     if (*pmgf1md == NULL)
509         return 0;
510     if (pss->saltLength)
511         *psaltlen = ASN1_INTEGER_get(pss->saltLength);
512     else
513         *psaltlen = ossl_rsa_pss_params_30_saltlen(&pss_params);
514     if (pss->trailerField)
515         *ptrailerField = ASN1_INTEGER_get(pss->trailerField);
516     else
517         *ptrailerField = ossl_rsa_pss_params_30_trailerfield(&pss_params);;
518 
519     return 1;
520 }
521 
522 int ossl_rsa_param_decode(RSA *rsa, const X509_ALGOR *alg)
523 {
524     RSA_PSS_PARAMS *pss;
525     const ASN1_OBJECT *algoid;
526     const void *algp;
527     int algptype;
528 
529     X509_ALGOR_get0(&algoid, &algptype, &algp, alg);
530     if (OBJ_obj2nid(algoid) != EVP_PKEY_RSA_PSS)
531         return 1;
532     if (algptype == V_ASN1_UNDEF)
533         return 1;
534     if (algptype != V_ASN1_SEQUENCE) {
535         ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_PSS_PARAMETERS);
536         return 0;
537     }
538     if ((pss = ossl_rsa_pss_decode(alg)) == NULL
539         || !ossl_rsa_set0_pss_params(rsa, pss)) {
540         RSA_PSS_PARAMS_free(pss);
541         return 0;
542     }
543     if (!ossl_rsa_sync_to_pss_params_30(rsa))
544         return 0;
545     return 1;
546 }
547 
548 RSA *ossl_rsa_key_from_pkcs8(const PKCS8_PRIV_KEY_INFO *p8inf,
549                              OSSL_LIB_CTX *libctx, const char *propq)
550 {
551     const unsigned char *p;
552     RSA *rsa;
553     int pklen;
554     const X509_ALGOR *alg;
555 
556     if (!PKCS8_pkey_get0(NULL, &p, &pklen, &alg, p8inf))
557         return 0;
558     rsa = d2i_RSAPrivateKey(NULL, &p, pklen);
559     if (rsa == NULL) {
560         ERR_raise(ERR_LIB_RSA, ERR_R_RSA_LIB);
561         return NULL;
562     }
563     if (!ossl_rsa_param_decode(rsa, alg)) {
564         RSA_free(rsa);
565         return NULL;
566     }
567 
568     RSA_clear_flags(rsa, RSA_FLAG_TYPE_MASK);
569     switch (OBJ_obj2nid(alg->algorithm)) {
570     case EVP_PKEY_RSA:
571         RSA_set_flags(rsa, RSA_FLAG_TYPE_RSA);
572         break;
573     case EVP_PKEY_RSA_PSS:
574         RSA_set_flags(rsa, RSA_FLAG_TYPE_RSASSAPSS);
575         break;
576     default:
577         /* Leave the type bits zero */
578         break;
579     }
580 
581     return rsa;
582 }
583 #endif
584