xref: /openssl/crypto/evp/keymgmt_lib.c (revision b6461792)
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  */
match_type(const EVP_KEYMGMT * keymgmt1,const EVP_KEYMGMT * keymgmt2)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 
evp_keymgmt_util_try_import(const OSSL_PARAM params[],void * arg)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_EVP_LIB);
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 
evp_keymgmt_util_assign_pkey(EVP_PKEY * pkey,EVP_KEYMGMT * keymgmt,void * keydata)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 
evp_keymgmt_util_make_pkey(EVP_KEYMGMT * keymgmt,void * keydata)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 
evp_keymgmt_util_export(const EVP_PKEY * pk,int selection,OSSL_CALLBACK * export_cb,void * export_cbarg)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 
evp_keymgmt_util_export_to_provider(EVP_PKEY * pk,EVP_KEYMGMT * keymgmt,int selection)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);
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 
op_cache_free(OP_CACHE_ELEM * e)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 
evp_keymgmt_util_clear_operation_cache(EVP_PKEY * pk)222 int evp_keymgmt_util_clear_operation_cache(EVP_PKEY *pk)
223 {
224     if (pk != NULL) {
225         sk_OP_CACHE_ELEM_pop_free(pk->operation_cache, op_cache_free);
226         pk->operation_cache = NULL;
227     }
228 
229     return 1;
230 }
231 
evp_keymgmt_util_find_operation_cache(EVP_PKEY * pk,EVP_KEYMGMT * keymgmt,int selection)232 OP_CACHE_ELEM *evp_keymgmt_util_find_operation_cache(EVP_PKEY *pk,
233                                                      EVP_KEYMGMT *keymgmt,
234                                                      int selection)
235 {
236     int i, end = sk_OP_CACHE_ELEM_num(pk->operation_cache);
237     OP_CACHE_ELEM *p;
238 
239     /*
240      * A comparison and sk_P_CACHE_ELEM_find() are avoided to not cause
241      * problems when we've only a read lock.
242      * A keymgmt is a match if the |keymgmt| pointers are identical or if the
243      * provider and the name ID match
244      */
245     for (i = 0; i < end; i++) {
246         p = sk_OP_CACHE_ELEM_value(pk->operation_cache, i);
247         if ((p->selection & selection) == selection
248                 && (keymgmt == p->keymgmt
249                     || (keymgmt->name_id == p->keymgmt->name_id
250                         && keymgmt->prov == p->keymgmt->prov)))
251             return p;
252     }
253     return NULL;
254 }
255 
evp_keymgmt_util_cache_keydata(EVP_PKEY * pk,EVP_KEYMGMT * keymgmt,void * keydata,int selection)256 int evp_keymgmt_util_cache_keydata(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt,
257                                    void *keydata, int selection)
258 {
259     OP_CACHE_ELEM *p = NULL;
260 
261     if (keydata != NULL) {
262         if (pk->operation_cache == NULL) {
263             pk->operation_cache = sk_OP_CACHE_ELEM_new_null();
264             if (pk->operation_cache == NULL)
265                 return 0;
266         }
267 
268         p = OPENSSL_malloc(sizeof(*p));
269         if (p == NULL)
270             return 0;
271         p->keydata = keydata;
272         p->keymgmt = keymgmt;
273         p->selection = selection;
274 
275         if (!EVP_KEYMGMT_up_ref(keymgmt)) {
276             OPENSSL_free(p);
277             return 0;
278         }
279 
280         if (!sk_OP_CACHE_ELEM_push(pk->operation_cache, p)) {
281             EVP_KEYMGMT_free(keymgmt);
282             OPENSSL_free(p);
283             return 0;
284         }
285     }
286     return 1;
287 }
288 
evp_keymgmt_util_cache_keyinfo(EVP_PKEY * pk)289 void evp_keymgmt_util_cache_keyinfo(EVP_PKEY *pk)
290 {
291     /*
292      * Cache information about the provider "origin" key.
293      *
294      * This services functions like EVP_PKEY_get_size, EVP_PKEY_get_bits, etc
295      */
296     if (pk->keydata != NULL) {
297         int bits = 0;
298         int security_bits = 0;
299         int size = 0;
300         OSSL_PARAM params[4];
301 
302         params[0] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_BITS, &bits);
303         params[1] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_SECURITY_BITS,
304                                              &security_bits);
305         params[2] = OSSL_PARAM_construct_int(OSSL_PKEY_PARAM_MAX_SIZE, &size);
306         params[3] = OSSL_PARAM_construct_end();
307         if (evp_keymgmt_get_params(pk->keymgmt, pk->keydata, params)) {
308             pk->cache.size = size;
309             pk->cache.bits = bits;
310             pk->cache.security_bits = security_bits;
311         }
312     }
313 }
314 
evp_keymgmt_util_fromdata(EVP_PKEY * target,EVP_KEYMGMT * keymgmt,int selection,const OSSL_PARAM params[])315 void *evp_keymgmt_util_fromdata(EVP_PKEY *target, EVP_KEYMGMT *keymgmt,
316                                 int selection, const OSSL_PARAM params[])
317 {
318     void *keydata = NULL;
319 
320     if ((keydata = evp_keymgmt_newdata(keymgmt)) == NULL
321         || !evp_keymgmt_import(keymgmt, keydata, selection, params)
322         || !evp_keymgmt_util_assign_pkey(target, keymgmt, keydata)) {
323         evp_keymgmt_freedata(keymgmt, keydata);
324         keydata = NULL;
325     }
326     return keydata;
327 }
328 
evp_keymgmt_util_has(EVP_PKEY * pk,int selection)329 int evp_keymgmt_util_has(EVP_PKEY *pk, int selection)
330 {
331     /* Check if key is even assigned */
332     if (pk->keymgmt == NULL)
333         return 0;
334 
335     return evp_keymgmt_has(pk->keymgmt, pk->keydata, selection);
336 }
337 
338 /*
339  * evp_keymgmt_util_match() doesn't just look at the provider side "origin",
340  * but also in the operation cache to see if there's any common keymgmt that
341  * supplies OP_keymgmt_match.
342  *
343  * evp_keymgmt_util_match() adheres to the return values that EVP_PKEY_eq()
344  * and EVP_PKEY_parameters_eq() return, i.e.:
345  *
346  *  1   same key
347  *  0   not same key
348  * -1   not same key type
349  * -2   unsupported operation
350  */
evp_keymgmt_util_match(EVP_PKEY * pk1,EVP_PKEY * pk2,int selection)351 int evp_keymgmt_util_match(EVP_PKEY *pk1, EVP_PKEY *pk2, int selection)
352 {
353     EVP_KEYMGMT *keymgmt1 = NULL, *keymgmt2 = NULL;
354     void *keydata1 = NULL, *keydata2 = NULL;
355 
356     if (pk1 == NULL || pk2 == NULL) {
357         if (pk1 == NULL && pk2 == NULL)
358             return 1;
359         return 0;
360     }
361 
362     keymgmt1 = pk1->keymgmt;
363     keydata1 = pk1->keydata;
364     keymgmt2 = pk2->keymgmt;
365     keydata2 = pk2->keydata;
366 
367     if (keymgmt1 != keymgmt2) {
368         /*
369          * The condition for a successful cross export is that the
370          * keydata to be exported is NULL (typed, but otherwise empty
371          * EVP_PKEY), or that it was possible to export it with
372          * evp_keymgmt_util_export_to_provider().
373          *
374          * We use |ok| to determine if it's ok to cross export one way,
375          * but also to determine if we should attempt a cross export
376          * the other way.  There's no point doing it both ways.
377          */
378         int ok = 0;
379 
380         /* Complex case, where the keymgmt differ */
381         if (keymgmt1 != NULL
382             && keymgmt2 != NULL
383             && !match_type(keymgmt1, keymgmt2)) {
384             ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
385             return -1;           /* Not the same type */
386         }
387 
388         /*
389          * The key types are determined to match, so we try cross export,
390          * but only to keymgmt's that supply a matching function.
391          */
392         if (keymgmt2 != NULL
393             && keymgmt2->match != NULL) {
394             void *tmp_keydata = NULL;
395 
396             ok = 1;
397             if (keydata1 != NULL) {
398                 tmp_keydata =
399                     evp_keymgmt_util_export_to_provider(pk1, keymgmt2,
400                                                         selection);
401                 ok = (tmp_keydata != NULL);
402             }
403             if (ok) {
404                 keymgmt1 = keymgmt2;
405                 keydata1 = tmp_keydata;
406             }
407         }
408         /*
409          * If we've successfully cross exported one way, there's no point
410          * doing it the other way, hence the |!ok| check.
411          */
412         if (!ok
413             && keymgmt1 != NULL
414             && keymgmt1->match != NULL) {
415             void *tmp_keydata = NULL;
416 
417             ok = 1;
418             if (keydata2 != NULL) {
419                 tmp_keydata =
420                     evp_keymgmt_util_export_to_provider(pk2, keymgmt1,
421                                                         selection);
422                 ok = (tmp_keydata != NULL);
423             }
424             if (ok) {
425                 keymgmt2 = keymgmt1;
426                 keydata2 = tmp_keydata;
427             }
428         }
429     }
430 
431     /* If we still don't have matching keymgmt implementations, we give up */
432     if (keymgmt1 != keymgmt2)
433         return -2;
434 
435     /* If both keydata are NULL, then they're the same key */
436     if (keydata1 == NULL && keydata2 == NULL)
437         return 1;
438     /* If only one of the keydata is NULL, then they're different keys */
439     if (keydata1 == NULL || keydata2 == NULL)
440         return 0;
441     /* If both keydata are non-NULL, we let the backend decide */
442     return evp_keymgmt_match(keymgmt1, keydata1, keydata2, selection);
443 }
444 
evp_keymgmt_util_copy(EVP_PKEY * to,EVP_PKEY * from,int selection)445 int evp_keymgmt_util_copy(EVP_PKEY *to, EVP_PKEY *from, int selection)
446 {
447     /* Save copies of pointers we want to play with without affecting |to| */
448     EVP_KEYMGMT *to_keymgmt = to->keymgmt;
449     void *to_keydata = to->keydata, *alloc_keydata = NULL;
450 
451     /* An unassigned key can't be copied */
452     if (from == NULL || from->keydata == NULL)
453         return 0;
454 
455     /*
456      * If |to| is unassigned, ensure it gets the same KEYMGMT as |from|,
457      * Note that the final setting of KEYMGMT is done further down, with
458      * EVP_PKEY_set_type_by_keymgmt(); we don't want to do that prematurely.
459      */
460     if (to_keymgmt == NULL)
461         to_keymgmt = from->keymgmt;
462 
463     if (to_keymgmt == from->keymgmt && to_keymgmt->dup != NULL
464         && to_keydata == NULL) {
465         to_keydata = alloc_keydata = evp_keymgmt_dup(to_keymgmt,
466                                                      from->keydata,
467                                                      selection);
468         if (to_keydata == NULL)
469             return 0;
470     } else if (match_type(to_keymgmt, from->keymgmt)) {
471         struct evp_keymgmt_util_try_import_data_st import_data;
472 
473         import_data.keymgmt = to_keymgmt;
474         import_data.keydata = to_keydata;
475         import_data.selection = selection;
476 
477         if (!evp_keymgmt_util_export(from, selection,
478                                      &evp_keymgmt_util_try_import,
479                                      &import_data))
480             return 0;
481 
482         /*
483          * In case to_keydata was previously unallocated,
484          * evp_keymgmt_util_try_import() may have created it for us.
485          */
486         if (to_keydata == NULL)
487             to_keydata = alloc_keydata = import_data.keydata;
488     } else {
489         ERR_raise(ERR_LIB_EVP, EVP_R_DIFFERENT_KEY_TYPES);
490         return 0;
491     }
492 
493     /*
494      * We only need to set the |to| type when its |keymgmt| isn't set.
495      * We can then just set its |keydata| to what we have, which might
496      * be exactly what it had when entering this function.
497      * This is a bit different from using evp_keymgmt_util_assign_pkey(),
498      * which isn't as careful with |to|'s original |keymgmt|, since it's
499      * meant to forcibly reassign an EVP_PKEY no matter what, which is
500      * why we don't use that one here.
501      */
502     if (to->keymgmt == NULL
503         && !EVP_PKEY_set_type_by_keymgmt(to, to_keymgmt)) {
504         evp_keymgmt_freedata(to_keymgmt, alloc_keydata);
505         return 0;
506     }
507     to->keydata = to_keydata;
508     evp_keymgmt_util_cache_keyinfo(to);
509 
510     return 1;
511 }
512 
evp_keymgmt_util_gen(EVP_PKEY * target,EVP_KEYMGMT * keymgmt,void * genctx,OSSL_CALLBACK * cb,void * cbarg)513 void *evp_keymgmt_util_gen(EVP_PKEY *target, EVP_KEYMGMT *keymgmt,
514                            void *genctx, OSSL_CALLBACK *cb, void *cbarg)
515 {
516     void *keydata = NULL;
517 
518     if ((keydata = evp_keymgmt_gen(keymgmt, genctx, cb, cbarg)) == NULL
519         || !evp_keymgmt_util_assign_pkey(target, keymgmt, keydata)) {
520         evp_keymgmt_freedata(keymgmt, keydata);
521         keydata = NULL;
522     }
523 
524     return keydata;
525 }
526 
527 /*
528  * Returns the same numbers as EVP_PKEY_get_default_digest_name()
529  * When the string from the EVP_KEYMGMT implementation is "", we use
530  * SN_undef, since that corresponds to what EVP_PKEY_get_default_nid()
531  * returns for no digest.
532  */
evp_keymgmt_util_get_deflt_digest_name(EVP_KEYMGMT * keymgmt,void * keydata,char * mdname,size_t mdname_sz)533 int evp_keymgmt_util_get_deflt_digest_name(EVP_KEYMGMT *keymgmt,
534                                            void *keydata,
535                                            char *mdname, size_t mdname_sz)
536 {
537     OSSL_PARAM params[3];
538     char mddefault[100] = "";
539     char mdmandatory[100] = "";
540     char *result = NULL;
541     int rv = -2;
542 
543     params[0] =
544         OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_DEFAULT_DIGEST,
545                                          mddefault, sizeof(mddefault));
546     params[1] =
547         OSSL_PARAM_construct_utf8_string(OSSL_PKEY_PARAM_MANDATORY_DIGEST,
548                                          mdmandatory,
549                                          sizeof(mdmandatory));
550     params[2] = OSSL_PARAM_construct_end();
551 
552     if (!evp_keymgmt_get_params(keymgmt, keydata, params))
553         return 0;
554 
555     if (OSSL_PARAM_modified(params + 1)) {
556         if (params[1].return_size <= 1) /* Only a NUL byte */
557             result = SN_undef;
558         else
559             result = mdmandatory;
560         rv = 2;
561     } else if (OSSL_PARAM_modified(params)) {
562         if (params[0].return_size <= 1) /* Only a NUL byte */
563             result = SN_undef;
564         else
565             result = mddefault;
566         rv = 1;
567     }
568     if (rv > 0)
569         OPENSSL_strlcpy(mdname, result, mdname_sz);
570     return rv;
571 }
572 
573 /*
574  * If |keymgmt| has the method function |query_operation_name|, use it to get
575  * the name of a supported operation identity.  Otherwise, return the keytype,
576  * assuming that it works as a default operation name.
577  */
evp_keymgmt_util_query_operation_name(EVP_KEYMGMT * keymgmt,int op_id)578 const char *evp_keymgmt_util_query_operation_name(EVP_KEYMGMT *keymgmt,
579                                                   int op_id)
580 {
581     const char *name = NULL;
582 
583     if (keymgmt != NULL) {
584         if (keymgmt->query_operation_name != NULL)
585             name = keymgmt->query_operation_name(op_id);
586         if (name == NULL)
587             name = EVP_KEYMGMT_get0_name(keymgmt);
588     }
589     return name;
590 }
591