xref: /freebsd/crypto/openssl/crypto/evp/keymgmt_lib.c (revision 44096ebd22ddd0081a357011714eff8963614b65)
1 /*
2  * Copyright 2019-2024 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 <openssl/core_names.h>
11 #include "internal/cryptlib.h"
12 #include "internal/nelem.h"
13 #include "crypto/evp.h"
14 #include "internal/core.h"
15 #include "internal/provider.h"
16 #include "evp_local.h"
17 
18 /*
19  * match_type() checks if two EVP_KEYMGMT are matching key types.  This
20  * function assumes that the caller has made all the necessary NULL checks.
21  */
22 static int match_type(const EVP_KEYMGMT *keymgmt1, const EVP_KEYMGMT *keymgmt2)
23 {
24     const char *name2 = EVP_KEYMGMT_get0_name(keymgmt2);
25 
26     return EVP_KEYMGMT_is_a(keymgmt1, name2);
27 }
28 
29 int evp_keymgmt_util_try_import(const OSSL_PARAM params[], void *arg)
30 {
31     struct evp_keymgmt_util_try_import_data_st *data = arg;
32     int delete_on_error = 0;
33 
34     /* Just in time creation of keydata */
35     if (data->keydata == NULL) {
36         if ((data->keydata = evp_keymgmt_newdata(data->keymgmt)) == NULL) {
37             ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
38             return 0;
39         }
40         delete_on_error = 1;
41     }
42 
43     /*
44      * It's fine if there was no data to transfer, we just end up with an
45      * empty destination key.
46      */
47     if (params[0].key == NULL)
48         return 1;
49 
50     if (evp_keymgmt_import(data->keymgmt, data->keydata, data->selection,
51                            params))
52         return 1;
53     if (delete_on_error) {
54         evp_keymgmt_freedata(data->keymgmt, data->keydata);
55         data->keydata = NULL;
56     }
57     return 0;
58 }
59 
60 int evp_keymgmt_util_assign_pkey(EVP_PKEY *pkey, EVP_KEYMGMT *keymgmt,
61                                  void *keydata)
62 {
63     if (pkey == NULL || keymgmt == NULL || keydata == NULL
64         || !EVP_PKEY_set_type_by_keymgmt(pkey, keymgmt)) {
65         ERR_raise(ERR_LIB_EVP, ERR_R_INTERNAL_ERROR);
66         return 0;
67     }
68     pkey->keydata = keydata;
69     evp_keymgmt_util_cache_keyinfo(pkey);
70     return 1;
71 }
72 
73 EVP_PKEY *evp_keymgmt_util_make_pkey(EVP_KEYMGMT *keymgmt, void *keydata)
74 {
75     EVP_PKEY *pkey = NULL;
76 
77     if (keymgmt == NULL
78         || keydata == NULL
79         || (pkey = EVP_PKEY_new()) == NULL
80         || !evp_keymgmt_util_assign_pkey(pkey, keymgmt, keydata)) {
81         EVP_PKEY_free(pkey);
82         return NULL;
83     }
84     return pkey;
85 }
86 
87 int evp_keymgmt_util_export(const EVP_PKEY *pk, int selection,
88                             OSSL_CALLBACK *export_cb, void *export_cbarg)
89 {
90     if (pk == NULL || export_cb == NULL)
91         return 0;
92     return evp_keymgmt_export(pk->keymgmt, pk->keydata, selection,
93                               export_cb, export_cbarg);
94 }
95 
96 void *evp_keymgmt_util_export_to_provider(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt,
97                                           int selection)
98 {
99     struct evp_keymgmt_util_try_import_data_st import_data;
100     OP_CACHE_ELEM *op;
101 
102     /* Export to where? */
103     if (keymgmt == NULL)
104         return NULL;
105 
106     /* If we have an unassigned key, give up */
107     if (pk->keydata == NULL)
108         return NULL;
109 
110     /*
111      * If |keymgmt| matches the "origin" |keymgmt|, there is no more to do.
112      * The "origin" is determined by the |keymgmt| pointers being identical
113      * or when the provider and the name ID match.  The latter case handles the
114      * situation where the fetch cache is flushed and a "new" key manager is
115      * created.
116      */
117     if (pk->keymgmt == keymgmt
118         || (pk->keymgmt->name_id == keymgmt->name_id
119             && pk->keymgmt->prov == keymgmt->prov))
120         return pk->keydata;
121 
122     if (!CRYPTO_THREAD_read_lock(pk->lock))
123         return NULL;
124     /*
125      * If the provider native "origin" hasn't changed since last time, we
126      * try to find our keymgmt in the operation cache.  If it has changed
127      * and our keymgmt isn't found, we will clear the cache further down.
128      */
129     if (pk->dirty_cnt == pk->dirty_cnt_copy) {
130         /* If this key is already exported to |keymgmt|, no more to do */
131         op = evp_keymgmt_util_find_operation_cache(pk, keymgmt, selection);
132         if (op != NULL && op->keymgmt != NULL) {
133             void *ret = op->keydata;
134 
135             CRYPTO_THREAD_unlock(pk->lock);
136             return ret;
137         }
138     }
139     CRYPTO_THREAD_unlock(pk->lock);
140 
141     /* If the "origin" |keymgmt| doesn't support exporting, give up */
142     if (pk->keymgmt->export == NULL)
143         return NULL;
144 
145     /*
146      * Make sure that the type of the keymgmt to export to matches the type
147      * of the "origin"
148      */
149     if (!ossl_assert(match_type(pk->keymgmt, keymgmt)))
150         return NULL;
151 
152     /*
153      * We look at the already cached provider keys, and import from the
154      * first that supports it (i.e. use its export function), and export
155      * the imported data to the new provider.
156      */
157 
158     /* Setup for the export callback */
159     import_data.keydata = NULL;  /* evp_keymgmt_util_try_import will create it */
160     import_data.keymgmt = keymgmt;
161     import_data.selection = selection;
162 
163     /*
164      * The export function calls the callback (evp_keymgmt_util_try_import),
165      * which does the import for us.  If successful, we're done.
166      */
167     if (!evp_keymgmt_util_export(pk, selection,
168                                  &evp_keymgmt_util_try_import, &import_data))
169         /* If there was an error, bail out */
170         return NULL;
171 
172     if (!CRYPTO_THREAD_write_lock(pk->lock)) {
173         evp_keymgmt_freedata(keymgmt, import_data.keydata);
174         return NULL;
175     }
176     /* Check to make sure some other thread didn't get there first */
177     op = evp_keymgmt_util_find_operation_cache(pk, keymgmt, selection);
178     if (op != NULL && op->keydata != NULL) {
179         void *ret = op->keydata;
180 
181         CRYPTO_THREAD_unlock(pk->lock);
182 
183         /*
184          * Another thread seemms to have already exported this so we abandon
185          * all the work we just did.
186          */
187         evp_keymgmt_freedata(keymgmt, import_data.keydata);
188 
189         return ret;
190     }
191 
192     /*
193      * If the dirty counter changed since last time, then clear the
194      * operation cache.  In that case, we know that |i| is zero.
195      */
196     if (pk->dirty_cnt != pk->dirty_cnt_copy)
197         evp_keymgmt_util_clear_operation_cache(pk, 0);
198 
199     /* Add the new export to the operation cache */
200     if (!evp_keymgmt_util_cache_keydata(pk, keymgmt, import_data.keydata,
201                                         selection)) {
202         CRYPTO_THREAD_unlock(pk->lock);
203         evp_keymgmt_freedata(keymgmt, import_data.keydata);
204         return NULL;
205     }
206 
207     /* Synchronize the dirty count */
208     pk->dirty_cnt_copy = pk->dirty_cnt;
209 
210     CRYPTO_THREAD_unlock(pk->lock);
211 
212     return import_data.keydata;
213 }
214 
215 static void op_cache_free(OP_CACHE_ELEM *e)
216 {
217     evp_keymgmt_freedata(e->keymgmt, e->keydata);
218     EVP_KEYMGMT_free(e->keymgmt);
219     OPENSSL_free(e);
220 }
221 
222 int evp_keymgmt_util_clear_operation_cache(EVP_PKEY *pk, int locking)
223 {
224     if (pk != NULL) {
225         if (locking && pk->lock != NULL && !CRYPTO_THREAD_write_lock(pk->lock))
226             return 0;
227         sk_OP_CACHE_ELEM_pop_free(pk->operation_cache, op_cache_free);
228         pk->operation_cache = NULL;
229         if (locking && pk->lock != NULL)
230             CRYPTO_THREAD_unlock(pk->lock);
231     }
232 
233     return 1;
234 }
235 
236 OP_CACHE_ELEM *evp_keymgmt_util_find_operation_cache(EVP_PKEY *pk,
237                                                      EVP_KEYMGMT *keymgmt,
238                                                      int selection)
239 {
240     int i, end = sk_OP_CACHE_ELEM_num(pk->operation_cache);
241     OP_CACHE_ELEM *p;
242 
243     /*
244      * A comparison and sk_P_CACHE_ELEM_find() are avoided to not cause
245      * problems when we've only a read lock.
246      * A keymgmt is a match if the |keymgmt| pointers are identical or if the
247      * provider and the name ID match
248      */
249     for (i = 0; i < end; i++) {
250         p = sk_OP_CACHE_ELEM_value(pk->operation_cache, i);
251         if ((p->selection & selection) == selection
252                 && (keymgmt == p->keymgmt
253                     || (keymgmt->name_id == p->keymgmt->name_id
254                         && keymgmt->prov == p->keymgmt->prov)))
255             return p;
256     }
257     return NULL;
258 }
259 
260 int evp_keymgmt_util_cache_keydata(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt,
261                                    void *keydata, int selection)
262 {
263     OP_CACHE_ELEM *p = NULL;
264 
265     if (keydata != NULL) {
266         if (pk->operation_cache == NULL) {
267             pk->operation_cache = sk_OP_CACHE_ELEM_new_null();
268             if (pk->operation_cache == NULL)
269                 return 0;
270         }
271 
272         p = OPENSSL_malloc(sizeof(*p));
273         if (p == NULL)
274             return 0;
275         p->keydata = keydata;
276         p->keymgmt = keymgmt;
277         p->selection = selection;
278 
279         if (!EVP_KEYMGMT_up_ref(keymgmt)) {
280             OPENSSL_free(p);
281             return 0;
282         }
283 
284         if (!sk_OP_CACHE_ELEM_push(pk->operation_cache, p)) {
285             EVP_KEYMGMT_free(keymgmt);
286             OPENSSL_free(p);
287             return 0;
288         }
289     }
290     return 1;
291 }
292 
293 void evp_keymgmt_util_cache_keyinfo(EVP_PKEY *pk)
294 {
295     /*
296      * Cache information about the provider "origin" key.
297      *
298      * This services functions like EVP_PKEY_get_size, EVP_PKEY_get_bits, etc
299      */
300     if (pk->keydata != NULL) {
301         int bits = 0;
302         int security_bits = 0;
303         int size = 0;
304         OSSL_PARAM params[4];
305 
306         params[0] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_BITS, &bits);
307         params[1] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_SECURITY_BITS,
308                                              &security_bits);
309         params[2] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_MAX_SIZE, &size);
310         params[3] = OSSL_PARAM_construct_end();
311         if (evp_keymgmt_get_params(pk->keymgmt, pk->keydata, params)) {
312             pk->cache.size = size;
313             pk->cache.bits = bits;
314             pk->cache.security_bits = security_bits;
315         }
316     }
317 }
318 
319 void *evp_keymgmt_util_fromdata(EVP_PKEY *target, EVP_KEYMGMT *keymgmt,
320                                 int selection, const OSSL_PARAM params[])
321 {
322     void *keydata = NULL;
323 
324     if ((keydata = evp_keymgmt_newdata(keymgmt)) == NULL
325         || !evp_keymgmt_import(keymgmt, keydata, selection, params)
326         || !evp_keymgmt_util_assign_pkey(target, keymgmt, keydata)) {
327         evp_keymgmt_freedata(keymgmt, keydata);
328         keydata = NULL;
329     }
330     return keydata;
331 }
332 
333 int evp_keymgmt_util_has(EVP_PKEY *pk, int selection)
334 {
335     /* Check if key is even assigned */
336     if (pk->keymgmt == NULL)
337         return 0;
338 
339     return evp_keymgmt_has(pk->keymgmt, pk->keydata, selection);
340 }
341 
342 /*
343  * evp_keymgmt_util_match() doesn't just look at the provider side "origin",
344  * but also in the operation cache to see if there's any common keymgmt that
345  * supplies OP_keymgmt_match.
346  *
347  * evp_keymgmt_util_match() adheres to the return values that EVP_PKEY_eq()
348  * and EVP_PKEY_parameters_eq() return, i.e.:
349  *
350  *  1   same key
351  *  0   not same key
352  * -1   not same key type
353  * -2   unsupported operation
354  */
355 int evp_keymgmt_util_match(EVP_PKEY *pk1, EVP_PKEY *pk2, int selection)
356 {
357     EVP_KEYMGMT *keymgmt1 = NULL, *keymgmt2 = NULL;
358     void *keydata1 = NULL, *keydata2 = NULL;
359 
360     if (pk1 == NULL || pk2 == NULL) {
361         if (pk1 == NULL && pk2 == NULL)
362             return 1;
363         return 0;
364     }
365 
366     keymgmt1 = pk1->keymgmt;
367     keydata1 = pk1->keydata;
368     keymgmt2 = pk2->keymgmt;
369     keydata2 = pk2->keydata;
370 
371     if (keymgmt1 != keymgmt2) {
372         /*
373          * The condition for a successful cross export is that the
374          * keydata to be exported is NULL (typed, but otherwise empty
375          * EVP_PKEY), or that it was possible to export it with
376          * evp_keymgmt_util_export_to_provider().
377          *
378          * We use |ok| to determine if it's ok to cross export one way,
379          * but also to determine if we should attempt a cross export
380          * the other way.  There's no point doing it both ways.
381          */
382         int ok = 0;
383 
384         /* Complex case, where the keymgmt differ */
385         if (keymgmt1 != NULL
386             && keymgmt2 != NULL
387             && !match_type(keymgmt1, keymgmt2)) {
388             ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
389             return -1;           /* Not the same type */
390         }
391 
392         /*
393          * The key types are determined to match, so we try cross export,
394          * but only to keymgmt's that supply a matching function.
395          */
396         if (keymgmt2 != NULL
397             && keymgmt2->match != NULL) {
398             void *tmp_keydata = NULL;
399 
400             ok = 1;
401             if (keydata1 != NULL) {
402                 tmp_keydata =
403                     evp_keymgmt_util_export_to_provider(pk1, keymgmt2,
404                                                         selection);
405                 ok = (tmp_keydata != NULL);
406             }
407             if (ok) {
408                 keymgmt1 = keymgmt2;
409                 keydata1 = tmp_keydata;
410             }
411         }
412         /*
413          * If we've successfully cross exported one way, there's no point
414          * doing it the other way, hence the |!ok| check.
415          */
416         if (!ok
417             && keymgmt1 != NULL
418             && keymgmt1->match != NULL) {
419             void *tmp_keydata = NULL;
420 
421             ok = 1;
422             if (keydata2 != NULL) {
423                 tmp_keydata =
424                     evp_keymgmt_util_export_to_provider(pk2, keymgmt1,
425                                                         selection);
426                 ok = (tmp_keydata != NULL);
427             }
428             if (ok) {
429                 keymgmt2 = keymgmt1;
430                 keydata2 = tmp_keydata;
431             }
432         }
433     }
434 
435     /* If we still don't have matching keymgmt implementations, we give up */
436     if (keymgmt1 != keymgmt2)
437         return -2;
438 
439     /* If both keydata are NULL, then they're the same key */
440     if (keydata1 == NULL && keydata2 == NULL)
441         return 1;
442     /* If only one of the keydata is NULL, then they're different keys */
443     if (keydata1 == NULL || keydata2 == NULL)
444         return 0;
445     /* If both keydata are non-NULL, we let the backend decide */
446     return evp_keymgmt_match(keymgmt1, keydata1, keydata2, selection);
447 }
448 
449 int evp_keymgmt_util_copy(EVP_PKEY *to, EVP_PKEY *from, int selection)
450 {
451     /* Save copies of pointers we want to play with without affecting |to| */
452     EVP_KEYMGMT *to_keymgmt = to->keymgmt;
453     void *to_keydata = to->keydata, *alloc_keydata = NULL;
454 
455     /* An unassigned key can't be copied */
456     if (from == NULL || from->keydata == NULL)
457         return 0;
458 
459     /*
460      * If |to| is unassigned, ensure it gets the same KEYMGMT as |from|,
461      * Note that the final setting of KEYMGMT is done further down, with
462      * EVP_PKEY_set_type_by_keymgmt(); we don't want to do that prematurely.
463      */
464     if (to_keymgmt == NULL)
465         to_keymgmt = from->keymgmt;
466 
467     if (to_keymgmt == from->keymgmt && to_keymgmt->dup != NULL
468         && to_keydata == NULL) {
469         to_keydata = alloc_keydata = evp_keymgmt_dup(to_keymgmt,
470                                                      from->keydata,
471                                                      selection);
472         if (to_keydata == NULL)
473             return 0;
474     } else if (match_type(to_keymgmt, from->keymgmt)) {
475         struct evp_keymgmt_util_try_import_data_st import_data;
476 
477         import_data.keymgmt = to_keymgmt;
478         import_data.keydata = to_keydata;
479         import_data.selection = selection;
480 
481         if (!evp_keymgmt_util_export(from, selection,
482                                      &evp_keymgmt_util_try_import,
483                                      &import_data))
484             return 0;
485 
486         /*
487          * In case to_keydata was previously unallocated,
488          * evp_keymgmt_util_try_import() may have created it for us.
489          */
490         if (to_keydata == NULL)
491             to_keydata = alloc_keydata = import_data.keydata;
492     } else {
493         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
494         return 0;
495     }
496 
497     /*
498      * We only need to set the |to| type when its |keymgmt| isn't set.
499      * We can then just set its |keydata| to what we have, which might
500      * be exactly what it had when entering this function.
501      * This is a bit different from using evp_keymgmt_util_assign_pkey(),
502      * which isn't as careful with |to|'s original |keymgmt|, since it's
503      * meant to forcibly reassign an EVP_PKEY no matter what, which is
504      * why we don't use that one here.
505      */
506     if (to->keymgmt == NULL
507         && !EVP_PKEY_set_type_by_keymgmt(to, to_keymgmt)) {
508         evp_keymgmt_freedata(to_keymgmt, alloc_keydata);
509         return 0;
510     }
511     to->keydata = to_keydata;
512     evp_keymgmt_util_cache_keyinfo(to);
513 
514     return 1;
515 }
516 
517 void *evp_keymgmt_util_gen(EVP_PKEY *target, EVP_KEYMGMT *keymgmt,
518                            void *genctx, OSSL_CALLBACK *cb, void *cbarg)
519 {
520     void *keydata = NULL;
521 
522     if ((keydata = evp_keymgmt_gen(keymgmt, genctx, cb, cbarg)) == NULL
523         || !evp_keymgmt_util_assign_pkey(target, keymgmt, keydata)) {
524         evp_keymgmt_freedata(keymgmt, keydata);
525         keydata = NULL;
526     }
527 
528     return keydata;
529 }
530 
531 /*
532  * Returns the same numbers as EVP_PKEY_get_default_digest_name()
533  * When the string from the EVP_KEYMGMT implementation is "", we use
534  * SN_undef, since that corresponds to what EVP_PKEY_get_default_nid()
535  * returns for no digest.
536  */
537 int evp_keymgmt_util_get_deflt_digest_name(EVP_KEYMGMT *keymgmt,
538                                            void *keydata,
539                                            char *mdname, size_t mdname_sz)
540 {
541     OSSL_PARAM params[3];
542     char mddefault[100] = "";
543     char mdmandatory[100] = "";
544     char *result = NULL;
545     int rv = -2;
546 
547     params[0] =
548         OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_DEFAULT_DIGEST,
549                                          mddefault, sizeof(mddefault));
550     params[1] =
551         OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_MANDATORY_DIGEST,
552                                          mdmandatory,
553                                          sizeof(mdmandatory));
554     params[2] = OSSL_PARAM_construct_end();
555 
556     if (!evp_keymgmt_get_params(keymgmt, keydata, params))
557         return 0;
558 
559     if (OSSL_PARAM_modified(params + 1)) {
560         if (params[1].return_size <= 1) /* Only a NUL byte */
561             result = SN_undef;
562         else
563             result = mdmandatory;
564         rv = 2;
565     } else if (OSSL_PARAM_modified(params)) {
566         if (params[0].return_size <= 1) /* Only a NUL byte */
567             result = SN_undef;
568         else
569             result = mddefault;
570         rv = 1;
571     }
572     if (rv > 0)
573         OPENSSL_strlcpy(mdname, result, mdname_sz);
574     return rv;
575 }
576 
577 /*
578  * If |keymgmt| has the method function |query_operation_name|, use it to get
579  * the name of a supported operation identity.  Otherwise, return the keytype,
580  * assuming that it works as a default operation name.
581  */
582 const char *evp_keymgmt_util_query_operation_name(EVP_KEYMGMT *keymgmt,
583                                                   int op_id)
584 {
585     const char *name = NULL;
586 
587     if (keymgmt != NULL) {
588         if (keymgmt->query_operation_name != NULL)
589             name = keymgmt->query_operation_name(op_id);
590         if (name == NULL)
591             name = EVP_KEYMGMT_get0_name(keymgmt);
592     }
593     return name;
594 }
595