1/*
2 * Copyright 2001-2023 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
4 *
5 * Licensed under the Apache License 2.0 (the "License").  You may not use
6 * this file except in compliance with the License.  You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
9 */
10
11/* We need to use some engine deprecated APIs */
12#define OPENSSL_SUPPRESS_DEPRECATED
13
14#include "eng_local.h"
15
16/*
17 * The linked-list of pointers to engine types. engine_list_head incorporates
18 * an implicit structural reference but engine_list_tail does not - the
19 * latter is a computational optimization and only points to something that
20 * is already pointed to by its predecessor in the list (or engine_list_head
21 * itself). In the same way, the use of the "prev" pointer in each ENGINE is
22 * to save excessive list iteration, it doesn't correspond to an extra
23 * structural reference. Hence, engine_list_head, and each non-null "next"
24 * pointer account for the list itself assuming exactly 1 structural
25 * reference on each list member.
26 */
27static ENGINE *engine_list_head = NULL;
28static ENGINE *engine_list_tail = NULL;
29
30/*
31 * The linked list of currently loaded dynamic engines.
32 */
33static ENGINE *engine_dyn_list_head = NULL;
34static ENGINE *engine_dyn_list_tail = NULL;
35
36/*
37 * This cleanup function is only needed internally. If it should be called,
38 * we register it with the "engine_cleanup_int()" stack to be called during
39 * cleanup.
40 */
41
42static void engine_list_cleanup(void)
43{
44    ENGINE *iterator = engine_list_head;
45
46    while (iterator != NULL) {
47        ENGINE_remove(iterator);
48        iterator = engine_list_head;
49    }
50    return;
51}
52
53/*
54 * These static functions starting with a lower case "engine_" always take
55 * place when global_engine_lock has been locked up.
56 */
57static int engine_list_add(ENGINE *e)
58{
59    int conflict = 0;
60    ENGINE *iterator = NULL;
61
62    if (e == NULL) {
63        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
64        return 0;
65    }
66    iterator = engine_list_head;
67    while (iterator && !conflict) {
68        conflict = (strcmp(iterator->id, e->id) == 0);
69        iterator = iterator->next;
70    }
71    if (conflict) {
72        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_CONFLICTING_ENGINE_ID);
73        return 0;
74    }
75    if (engine_list_head == NULL) {
76        /* We are adding to an empty list. */
77        if (engine_list_tail) {
78            ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
79            return 0;
80        }
81        /*
82         * The first time the list allocates, we should register the cleanup.
83         */
84        if (!engine_cleanup_add_last(engine_list_cleanup)) {
85            ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
86            return 0;
87        }
88        engine_list_head = e;
89        e->prev = NULL;
90    } else {
91        /* We are adding to the tail of an existing list. */
92        if ((engine_list_tail == NULL) || (engine_list_tail->next != NULL)) {
93            ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
94            return 0;
95        }
96        engine_list_tail->next = e;
97        e->prev = engine_list_tail;
98    }
99    /*
100     * Having the engine in the list assumes a structural reference.
101     */
102    e->struct_ref++;
103    ENGINE_REF_PRINT(e, 0, 1);
104    /* However it came to be, e is the last item in the list. */
105    engine_list_tail = e;
106    e->next = NULL;
107    return 1;
108}
109
110static int engine_list_remove(ENGINE *e)
111{
112    ENGINE *iterator;
113
114    if (e == NULL) {
115        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
116        return 0;
117    }
118    /* We need to check that e is in our linked list! */
119    iterator = engine_list_head;
120    while (iterator && (iterator != e))
121        iterator = iterator->next;
122    if (iterator == NULL) {
123        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_ENGINE_IS_NOT_IN_LIST);
124        return 0;
125    }
126    /* un-link e from the chain. */
127    if (e->next)
128        e->next->prev = e->prev;
129    if (e->prev)
130        e->prev->next = e->next;
131    /* Correct our head/tail if necessary. */
132    if (engine_list_head == e)
133        engine_list_head = e->next;
134    if (engine_list_tail == e)
135        engine_list_tail = e->prev;
136    engine_free_util(e, 0);
137    return 1;
138}
139
140/* Add engine to dynamic engine list. */
141int engine_add_dynamic_id(ENGINE *e, ENGINE_DYNAMIC_ID dynamic_id,
142                          int not_locked)
143{
144    int result = 0;
145    ENGINE *iterator = NULL;
146
147    if (e == NULL)
148        return 0;
149
150    if (e->dynamic_id == NULL && dynamic_id == NULL)
151        return 0;
152
153    if (not_locked && !CRYPTO_THREAD_write_lock(global_engine_lock))
154        return 0;
155
156    if (dynamic_id != NULL) {
157        iterator = engine_dyn_list_head;
158        while (iterator != NULL) {
159            if (iterator->dynamic_id == dynamic_id)
160                goto err;
161            iterator = iterator->next;
162        }
163        if (e->dynamic_id != NULL)
164            goto err;
165        e->dynamic_id = dynamic_id;
166    }
167
168    if (engine_dyn_list_head == NULL) {
169        /* We are adding to an empty list. */
170        if (engine_dyn_list_tail != NULL)
171            goto err;
172        engine_dyn_list_head = e;
173        e->prev_dyn = NULL;
174    } else {
175        /* We are adding to the tail of an existing list. */
176        if (engine_dyn_list_tail == NULL
177            || engine_dyn_list_tail->next_dyn != NULL)
178            goto err;
179        engine_dyn_list_tail->next_dyn = e;
180        e->prev_dyn = engine_dyn_list_tail;
181    }
182
183    engine_dyn_list_tail = e;
184    e->next_dyn = NULL;
185    result = 1;
186
187 err:
188    if (not_locked)
189        CRYPTO_THREAD_unlock(global_engine_lock);
190    return result;
191}
192
193/* Remove engine from dynamic engine list. */
194void engine_remove_dynamic_id(ENGINE *e, int not_locked)
195{
196    if (e == NULL || e->dynamic_id == NULL)
197        return;
198
199    if (not_locked && !CRYPTO_THREAD_write_lock(global_engine_lock))
200        return;
201
202    e->dynamic_id = NULL;
203
204    /* un-link e from the chain. */
205    if (e->next_dyn != NULL)
206        e->next_dyn->prev_dyn = e->prev_dyn;
207    if (e->prev_dyn != NULL)
208        e->prev_dyn->next_dyn = e->next_dyn;
209    /* Correct our head/tail if necessary. */
210    if (engine_dyn_list_head == e)
211        engine_dyn_list_head = e->next_dyn;
212    if (engine_dyn_list_tail == e)
213        engine_dyn_list_tail = e->prev_dyn;
214
215    if (not_locked)
216        CRYPTO_THREAD_unlock(global_engine_lock);
217}
218
219/* Get the first/last "ENGINE" type available. */
220ENGINE *ENGINE_get_first(void)
221{
222    ENGINE *ret;
223
224    if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
225        ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
226        return NULL;
227    }
228
229    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
230        return NULL;
231    ret = engine_list_head;
232    if (ret) {
233        ret->struct_ref++;
234        ENGINE_REF_PRINT(ret, 0, 1);
235    }
236    CRYPTO_THREAD_unlock(global_engine_lock);
237    return ret;
238}
239
240ENGINE *ENGINE_get_last(void)
241{
242    ENGINE *ret;
243
244    if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
245        ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
246        return NULL;
247    }
248
249    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
250        return NULL;
251    ret = engine_list_tail;
252    if (ret) {
253        ret->struct_ref++;
254        ENGINE_REF_PRINT(ret, 0, 1);
255    }
256    CRYPTO_THREAD_unlock(global_engine_lock);
257    return ret;
258}
259
260/* Iterate to the next/previous "ENGINE" type (NULL = end of the list). */
261ENGINE *ENGINE_get_next(ENGINE *e)
262{
263    ENGINE *ret = NULL;
264    if (e == NULL) {
265        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
266        return NULL;
267    }
268    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
269        return NULL;
270    ret = e->next;
271    if (ret) {
272        /* Return a valid structural reference to the next ENGINE */
273        ret->struct_ref++;
274        ENGINE_REF_PRINT(ret, 0, 1);
275    }
276    CRYPTO_THREAD_unlock(global_engine_lock);
277    /* Release the structural reference to the previous ENGINE */
278    ENGINE_free(e);
279    return ret;
280}
281
282ENGINE *ENGINE_get_prev(ENGINE *e)
283{
284    ENGINE *ret = NULL;
285    if (e == NULL) {
286        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
287        return NULL;
288    }
289    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
290        return NULL;
291    ret = e->prev;
292    if (ret) {
293        /* Return a valid structural reference to the next ENGINE */
294        ret->struct_ref++;
295        ENGINE_REF_PRINT(ret, 0, 1);
296    }
297    CRYPTO_THREAD_unlock(global_engine_lock);
298    /* Release the structural reference to the previous ENGINE */
299    ENGINE_free(e);
300    return ret;
301}
302
303/* Add another "ENGINE" type into the list. */
304int ENGINE_add(ENGINE *e)
305{
306    int to_return = 1;
307    if (e == NULL) {
308        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
309        return 0;
310    }
311    if ((e->id == NULL) || (e->name == NULL)) {
312        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_ID_OR_NAME_MISSING);
313        return 0;
314    }
315    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
316        return 0;
317    if (!engine_list_add(e)) {
318        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
319        to_return = 0;
320    }
321    CRYPTO_THREAD_unlock(global_engine_lock);
322    return to_return;
323}
324
325/* Remove an existing "ENGINE" type from the array. */
326int ENGINE_remove(ENGINE *e)
327{
328    int to_return = 1;
329    if (e == NULL) {
330        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
331        return 0;
332    }
333    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
334        return 0;
335    if (!engine_list_remove(e)) {
336        ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
337        to_return = 0;
338    }
339    CRYPTO_THREAD_unlock(global_engine_lock);
340    return to_return;
341}
342
343static void engine_cpy(ENGINE *dest, const ENGINE *src)
344{
345    dest->id = src->id;
346    dest->name = src->name;
347    dest->rsa_meth = src->rsa_meth;
348#ifndef OPENSSL_NO_DSA
349    dest->dsa_meth = src->dsa_meth;
350#endif
351#ifndef OPENSSL_NO_DH
352    dest->dh_meth = src->dh_meth;
353#endif
354#ifndef OPENSSL_NO_EC
355    dest->ec_meth = src->ec_meth;
356#endif
357    dest->rand_meth = src->rand_meth;
358    dest->ciphers = src->ciphers;
359    dest->digests = src->digests;
360    dest->pkey_meths = src->pkey_meths;
361    dest->destroy = src->destroy;
362    dest->init = src->init;
363    dest->finish = src->finish;
364    dest->ctrl = src->ctrl;
365    dest->load_privkey = src->load_privkey;
366    dest->load_pubkey = src->load_pubkey;
367    dest->cmd_defns = src->cmd_defns;
368    dest->flags = src->flags;
369    dest->dynamic_id = src->dynamic_id;
370    engine_add_dynamic_id(dest, NULL, 0);
371}
372
373ENGINE *ENGINE_by_id(const char *id)
374{
375    ENGINE *iterator;
376    char *load_dir = NULL;
377    if (id == NULL) {
378        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
379        return NULL;
380    }
381    ENGINE_load_builtin_engines();
382
383    if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
384        ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
385        return NULL;
386    }
387
388    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
389        return NULL;
390    iterator = engine_list_head;
391    while (iterator && (strcmp(id, iterator->id) != 0))
392        iterator = iterator->next;
393    if (iterator != NULL) {
394        /*
395         * We need to return a structural reference. If this is an ENGINE
396         * type that returns copies, make a duplicate - otherwise increment
397         * the existing ENGINE's reference count.
398         */
399        if (iterator->flags & ENGINE_FLAGS_BY_ID_COPY) {
400            ENGINE *cp = ENGINE_new();
401            if (cp == NULL)
402                iterator = NULL;
403            else {
404                engine_cpy(cp, iterator);
405                iterator = cp;
406            }
407        } else {
408            iterator->struct_ref++;
409            ENGINE_REF_PRINT(iterator, 0, 1);
410        }
411    }
412    CRYPTO_THREAD_unlock(global_engine_lock);
413    if (iterator != NULL)
414        return iterator;
415    /*
416     * Prevent infinite recursion if we're looking for the dynamic engine.
417     */
418    if (strcmp(id, "dynamic")) {
419        if ((load_dir = ossl_safe_getenv("OPENSSL_ENGINES")) == NULL)
420            load_dir = ENGINESDIR;
421        iterator = ENGINE_by_id("dynamic");
422        if (!iterator || !ENGINE_ctrl_cmd_string(iterator, "ID", id, 0) ||
423            !ENGINE_ctrl_cmd_string(iterator, "DIR_LOAD", "2", 0) ||
424            !ENGINE_ctrl_cmd_string(iterator, "DIR_ADD",
425                                    load_dir, 0) ||
426            !ENGINE_ctrl_cmd_string(iterator, "LIST_ADD", "1", 0) ||
427            !ENGINE_ctrl_cmd_string(iterator, "LOAD", NULL, 0))
428            goto notfound;
429        return iterator;
430    }
431 notfound:
432    ENGINE_free(iterator);
433    ERR_raise_data(ERR_LIB_ENGINE, ENGINE_R_NO_SUCH_ENGINE, "id=%s", id);
434    return NULL;
435    /* EEK! Experimental code ends */
436}
437
438int ENGINE_up_ref(ENGINE *e)
439{
440    int i;
441    if (e == NULL) {
442        ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
443        return 0;
444    }
445    CRYPTO_UP_REF(&e->struct_ref, &i, global_engine_lock);
446    return 1;
447}
448