crypto/engine/eng_list.c

   1 /*
   2  * Copyright 2001-2020 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 #include "eng_local.h"
  12
  13 /*
  14  * The linked-list of pointers to engine types. engine_list_head incorporates
  15  * an implicit structural reference but engine_list_tail does not - the
  16  * latter is a computational optimization and only points to something that
  17  * is already pointed to by its predecessor in the list (or engine_list_head
  18  * itself). In the same way, the use of the "prev" pointer in each ENGINE is
  19  * to save excessive list iteration, it doesn't correspond to an extra
  20  * structural reference. Hence, engine_list_head, and each non-null "next"
  21  * pointer account for the list itself assuming exactly 1 structural
  22  * reference on each list member.
  23  */
  24 static ENGINE *engine_list_head = NULL;
  25 static ENGINE *engine_list_tail = NULL;
  26
  27 /*
  28  * This cleanup function is only needed internally. If it should be called,
  29  * we register it with the "engine_cleanup_int()" stack to be called during
  30  * cleanup.
  31  */
  32
  33 static void engine_list_cleanup(void)
  34 {
  35     ENGINE *iterator = engine_list_head;
  36
  37     while (iterator != NULL) {
  38         ENGINE_remove(iterator);
  39         iterator = engine_list_head;
  40     }
  41     return;
  42 }
  43
  44 /*
  45  * These static functions starting with a lower case "engine_" always take
  46  * place when global_engine_lock has been locked up.
  47  */
  48 static int engine_list_add(ENGINE *e)
  49 {
  50     int conflict = 0;
  51     ENGINE *iterator = NULL;
  52
  53     if (e == NULL) {
  54         ENGINEerr(ENGINE_F_ENGINE_LIST_ADD, ERR_R_PASSED_NULL_PARAMETER);
  55         return 0;
  56     }
  57     iterator = engine_list_head;
  58     while (iterator && !conflict) {
  59         conflict = (strcmp(iterator->id, e->id) == 0);
  60         iterator = iterator->next;
  61     }
  62     if (conflict) {
  63         ENGINEerr(ENGINE_F_ENGINE_LIST_ADD, ENGINE_R_CONFLICTING_ENGINE_ID);
  64         return 0;
  65     }
  66     if (engine_list_head == NULL) {
  67         /* We are adding to an empty list. */
  68         if (engine_list_tail) {
  69             ENGINEerr(ENGINE_F_ENGINE_LIST_ADD, ENGINE_R_INTERNAL_LIST_ERROR);
  70             return 0;
  71         }
  72         engine_list_head = e;
  73         e->prev = NULL;
  74         /*
  75          * The first time the list allocates, we should register the cleanup.
  76          */
  77         engine_cleanup_add_last(engine_list_cleanup);
  78     } else {
  79         /* We are adding to the tail of an existing list. */
  80         if ((engine_list_tail == NULL) || (engine_list_tail->next != NULL)) {
  81             ENGINEerr(ENGINE_F_ENGINE_LIST_ADD, ENGINE_R_INTERNAL_LIST_ERROR);
  82             return 0;
  83         }
  84         engine_list_tail->next = e;
  85         e->prev = engine_list_tail;
  86     }
  87     /*
  88      * Having the engine in the list assumes a structural reference.
  89      */
  90     e->struct_ref++;
  91     engine_ref_debug(e, 0, 1);
  92     /* However it came to be, e is the last item in the list. */
  93     engine_list_tail = e;
  94     e->next = NULL;
  95     return 1;
  96 }
  97
  98 static int engine_list_remove(ENGINE *e)
  99 {
 100     ENGINE *iterator;
 101
 102     if (e == NULL) {
 103         ENGINEerr(ENGINE_F_ENGINE_LIST_REMOVE, ERR_R_PASSED_NULL_PARAMETER);
 104         return 0;
 105     }
 106     /* We need to check that e is in our linked list! */
 107     iterator = engine_list_head;
 108     while (iterator && (iterator != e))
 109         iterator = iterator->next;
 110     if (iterator == NULL) {
 111         ENGINEerr(ENGINE_F_ENGINE_LIST_REMOVE,
 112                   ENGINE_R_ENGINE_IS_NOT_IN_LIST);
 113         return 0;
 114     }
 115     /* un-link e from the chain. */
 116     if (e->next)
 117         e->next->prev = e->prev;
 118     if (e->prev)
 119         e->prev->next = e->next;
 120     /* Correct our head/tail if necessary. */
 121     if (engine_list_head == e)
 122         engine_list_head = e->next;
 123     if (engine_list_tail == e)
 124         engine_list_tail = e->prev;
 125     engine_free_util(e, 0);
 126     return 1;
 127 }
 128
 129 /* Get the first/last "ENGINE" type available. */
 130 ENGINE *ENGINE_get_first(void)
 131 {
 132     ENGINE *ret;
 133
 134     if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
 135         ENGINEerr(ENGINE_F_ENGINE_GET_FIRST, ERR_R_MALLOC_FAILURE);
 136         return NULL;
 137     }
 138
 139     CRYPTO_THREAD_write_lock(global_engine_lock);
 140     ret = engine_list_head;
 141     if (ret) {
 142         ret->struct_ref++;
 143         engine_ref_debug(ret, 0, 1);
 144     }
 145     CRYPTO_THREAD_unlock(global_engine_lock);
 146     return ret;
 147 }
 148
 149 ENGINE *ENGINE_get_last(void)
 150 {
 151     ENGINE *ret;
 152
 153     if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
 154         ENGINEerr(ENGINE_F_ENGINE_GET_LAST, ERR_R_MALLOC_FAILURE);
 155         return NULL;
 156     }
 157
 158     CRYPTO_THREAD_write_lock(global_engine_lock);
 159     ret = engine_list_tail;
 160     if (ret) {
 161         ret->struct_ref++;
 162         engine_ref_debug(ret, 0, 1);
 163     }
 164     CRYPTO_THREAD_unlock(global_engine_lock);
 165     return ret;
 166 }
 167
 168 /* Iterate to the next/previous "ENGINE" type (NULL = end of the list). */
 169 ENGINE *ENGINE_get_next(ENGINE *e)
 170 {
 171     ENGINE *ret = NULL;
 172     if (e == NULL) {
 173         ENGINEerr(ENGINE_F_ENGINE_GET_NEXT, ERR_R_PASSED_NULL_PARAMETER);
 174         return 0;
 175     }
 176     CRYPTO_THREAD_write_lock(global_engine_lock);
 177     ret = e->next;
 178     if (ret) {
 179         /* Return a valid structural reference to the next ENGINE */
 180         ret->struct_ref++;
 181         engine_ref_debug(ret, 0, 1);
 182     }
 183     CRYPTO_THREAD_unlock(global_engine_lock);
 184     /* Release the structural reference to the previous ENGINE */
 185     ENGINE_free(e);
 186     return ret;
 187 }
 188
 189 ENGINE *ENGINE_get_prev(ENGINE *e)
 190 {
 191     ENGINE *ret = NULL;
 192     if (e == NULL) {
 193         ENGINEerr(ENGINE_F_ENGINE_GET_PREV, ERR_R_PASSED_NULL_PARAMETER);
 194         return 0;
 195     }
 196     CRYPTO_THREAD_write_lock(global_engine_lock);
 197     ret = e->prev;
 198     if (ret) {
 199         /* Return a valid structural reference to the next ENGINE */
 200         ret->struct_ref++;
 201         engine_ref_debug(ret, 0, 1);
 202     }
 203     CRYPTO_THREAD_unlock(global_engine_lock);
 204     /* Release the structural reference to the previous ENGINE */
 205     ENGINE_free(e);
 206     return ret;
 207 }
 208
 209 /* Add another "ENGINE" type into the list. */
 210 int ENGINE_add(ENGINE *e)
 211 {
 212     int to_return = 1;
 213     if (e == NULL) {
 214         ENGINEerr(ENGINE_F_ENGINE_ADD, ERR_R_PASSED_NULL_PARAMETER);
 215         return 0;
 216     }
 217     if ((e->id == NULL) || (e->name == NULL)) {
 218         ENGINEerr(ENGINE_F_ENGINE_ADD, ENGINE_R_ID_OR_NAME_MISSING);
 219         return 0;
 220     }
 221     CRYPTO_THREAD_write_lock(global_engine_lock);
 222     if (!engine_list_add(e)) {
 223         ENGINEerr(ENGINE_F_ENGINE_ADD, ENGINE_R_INTERNAL_LIST_ERROR);
 224         to_return = 0;
 225     }
 226     CRYPTO_THREAD_unlock(global_engine_lock);
 227     return to_return;
 228 }
 229
 230 /* Remove an existing "ENGINE" type from the array. */
 231 int ENGINE_remove(ENGINE *e)
 232 {
 233     int to_return = 1;
 234     if (e == NULL) {
 235         ENGINEerr(ENGINE_F_ENGINE_REMOVE, ERR_R_PASSED_NULL_PARAMETER);
 236         return 0;
 237     }
 238     CRYPTO_THREAD_write_lock(global_engine_lock);
 239     if (!engine_list_remove(e)) {
 240         ENGINEerr(ENGINE_F_ENGINE_REMOVE, ENGINE_R_INTERNAL_LIST_ERROR);
 241         to_return = 0;
 242     }
 243     CRYPTO_THREAD_unlock(global_engine_lock);
 244     return to_return;
 245 }
 246
 247 static void engine_cpy(ENGINE *dest, const ENGINE *src)
 248 {
 249     dest->id = src->id;
 250     dest->name = src->name;
 251 #ifndef OPENSSL_NO_RSA
 252     dest->rsa_meth = src->rsa_meth;
 253 #endif
 254 #ifndef OPENSSL_NO_DSA
 255     dest->dsa_meth = src->dsa_meth;
 256 #endif
 257 #ifndef OPENSSL_NO_DH
 258     dest->dh_meth = src->dh_meth;
 259 #endif
 260 #ifndef OPENSSL_NO_EC
 261     dest->ec_meth = src->ec_meth;
 262 #endif
 263     dest->rand_meth = src->rand_meth;
 264     dest->ciphers = src->ciphers;
 265     dest->digests = src->digests;
 266     dest->pkey_meths = src->pkey_meths;
 267     dest->destroy = src->destroy;
 268     dest->init = src->init;
 269     dest->finish = src->finish;
 270     dest->ctrl = src->ctrl;
 271     dest->load_privkey = src->load_privkey;
 272     dest->load_pubkey = src->load_pubkey;
 273     dest->cmd_defns = src->cmd_defns;
 274     dest->flags = src->flags;
 275 }
 276
 277 ENGINE *ENGINE_by_id(const char *id)
 278 {
 279     ENGINE *iterator;
 280     char *load_dir = NULL;
 281     if (id == NULL) {
 282         ENGINEerr(ENGINE_F_ENGINE_BY_ID, ERR_R_PASSED_NULL_PARAMETER);
 283         return NULL;
 284     }
 285     ENGINE_load_builtin_engines();
 286
 287     if (!RUN_ONCE(&engine_lock_init, do_engine_lock_init)) {
 288         ENGINEerr(ENGINE_F_ENGINE_BY_ID, ERR_R_MALLOC_FAILURE);
 289         return NULL;
 290     }
 291
 292     CRYPTO_THREAD_write_lock(global_engine_lock);
 293     iterator = engine_list_head;
 294     while (iterator && (strcmp(id, iterator->id) != 0))
 295         iterator = iterator->next;
 296     if (iterator != NULL) {
 297         /*
 298          * We need to return a structural reference. If this is an ENGINE
 299          * type that returns copies, make a duplicate - otherwise increment
 300          * the existing ENGINE's reference count.
 301          */
 302         if (iterator->flags & ENGINE_FLAGS_BY_ID_COPY) {
 303             ENGINE *cp = ENGINE_new();
 304             if (cp == NULL)
 305                 iterator = NULL;
 306             else {
 307                 engine_cpy(cp, iterator);
 308                 iterator = cp;
 309             }
 310         } else {
 311             iterator->struct_ref++;
 312             engine_ref_debug(iterator, 0, 1);
 313         }
 314     }
 315     CRYPTO_THREAD_unlock(global_engine_lock);
 316     if (iterator != NULL)
 317         return iterator;
 318     /*
 319      * Prevent infinite recursion if we're looking for the dynamic engine.
 320      */
 321     if (strcmp(id, "dynamic")) {
 322         if ((load_dir = ossl_safe_getenv("OPENSSL_ENGINES")) == NULL)
 323             load_dir = ENGINESDIR;
 324         iterator = ENGINE_by_id("dynamic");
 325         if (!iterator || !ENGINE_ctrl_cmd_string(iterator, "ID", id, 0) ||
 326             !ENGINE_ctrl_cmd_string(iterator, "DIR_LOAD", "2", 0) ||
 327             !ENGINE_ctrl_cmd_string(iterator, "DIR_ADD",
 328                                     load_dir, 0) ||
 329             !ENGINE_ctrl_cmd_string(iterator, "LIST_ADD", "1", 0) ||
 330             !ENGINE_ctrl_cmd_string(iterator, "LOAD", NULL, 0))
 331             goto notfound;
 332         return iterator;
 333     }
 334  notfound:
 335     ENGINE_free(iterator);
 336     ENGINEerr(ENGINE_F_ENGINE_BY_ID, ENGINE_R_NO_SUCH_ENGINE);
 337     ERR_add_error_data(2, "id=", id);
 338     return NULL;
 339     /* EEK! Experimental code ends */
 340 }
 341
 342 int ENGINE_up_ref(ENGINE *e)
 343 {
 344     int i;
 345     if (e == NULL) {
 346         ENGINEerr(ENGINE_F_ENGINE_UP_REF, ERR_R_PASSED_NULL_PARAMETER);
 347         return 0;
 348     }
 349     CRYPTO_UP_REF(&e->struct_ref, &i, global_engine_lock);
 350     return 1;
 351 }