crypto/engine/eng_table.c

   1 /*
   2  * Copyright 2001-2024 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 "internal/cryptlib.h"
  11 #include <openssl/evp.h>
  12 #include <openssl/lhash.h>
  13 #include <openssl/trace.h>
  14 #include "eng_local.h"
  15
  16 /* The type of the items in the table */
  17 struct st_engine_pile {
  18     /* The 'nid' of this algorithm/mode */
  19     int nid;
  20     /* ENGINEs that implement this algorithm/mode. */
  21     STACK_OF(ENGINE) *sk;
  22     /* The default ENGINE to perform this algorithm/mode. */
  23     ENGINE *funct;
  24     /*
  25      * Zero if 'sk' is newer than the cached 'funct', non-zero otherwise
  26      */
  27     int uptodate;
  28 };
  29
  30 /* The type exposed in eng_local.h */
  31 struct st_engine_table {
  32     LHASH_OF(ENGINE_PILE) piles;
  33 };                              /* ENGINE_TABLE */
  34
  35 typedef struct st_engine_pile_doall {
  36     engine_table_doall_cb *cb;
  37     void *arg;
  38 } ENGINE_PILE_DOALL;
  39
  40 /* Global flags (ENGINE_TABLE_FLAG_***). */
  41 static unsigned int table_flags = 0;
  42
  43 /* API function manipulating 'table_flags' */
  44 unsigned int ENGINE_get_table_flags(void)
  45 {
  46     return table_flags;
  47 }
  48
  49 void ENGINE_set_table_flags(unsigned int flags)
  50 {
  51     table_flags = flags;
  52 }
  53
  54 /* Internal functions for the "piles" hash table */
  55 static unsigned long engine_pile_hash(const ENGINE_PILE *c)
  56 {
  57     return c->nid;
  58 }
  59
  60 static int engine_pile_cmp(const ENGINE_PILE *a, const ENGINE_PILE *b)
  61 {
  62     return a->nid - b->nid;
  63 }
  64
  65 static int int_table_check(ENGINE_TABLE **t, int create)
  66 {
  67     LHASH_OF(ENGINE_PILE) *lh;
  68
  69     if (*t)
  70         return 1;
  71     if (!create)
  72         return 0;
  73     if ((lh = lh_ENGINE_PILE_new(engine_pile_hash, engine_pile_cmp)) == NULL)
  74         return 0;
  75     *t = (ENGINE_TABLE *)lh;
  76     return 1;
  77 }
  78
  79 /*
  80  * Privately exposed (via eng_local.h) functions for adding and/or removing
  81  * ENGINEs from the implementation table
  82  */
  83 int engine_table_register(ENGINE_TABLE **table, ENGINE_CLEANUP_CB *cleanup,
  84                           ENGINE *e, const int *nids, int num_nids,
  85                           int setdefault)
  86 {
  87     int ret = 0, added = 0;
  88     ENGINE_PILE tmplate, *fnd;
  89
  90     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
  91         return 0;
  92     if (!(*table))
  93         added = 1;
  94     if (!int_table_check(table, 1))
  95         goto end;
  96     /* The cleanup callback needs to be added */
  97     if (added && !engine_cleanup_add_first(cleanup)) {
  98         lh_ENGINE_PILE_free(&(*table)->piles);
  99         *table = NULL;
 100         goto end;
 101     }
 102     while (num_nids--) {
 103         tmplate.nid = *nids;
 104         fnd = lh_ENGINE_PILE_retrieve(&(*table)->piles, &tmplate);
 105         if (!fnd) {
 106             fnd = OPENSSL_malloc(sizeof(*fnd));
 107             if (fnd == NULL)
 108                 goto end;
 109             fnd->uptodate = 1;
 110             fnd->nid = *nids;
 111             fnd->sk = sk_ENGINE_new_null();
 112             if (!fnd->sk) {
 113                 OPENSSL_free(fnd);
 114                 goto end;
 115             }
 116             fnd->funct = NULL;
 117             (void)lh_ENGINE_PILE_insert(&(*table)->piles, fnd);
 118             if (lh_ENGINE_PILE_retrieve(&(*table)->piles, &tmplate) != fnd) {
 119                 sk_ENGINE_free(fnd->sk);
 120                 OPENSSL_free(fnd);
 121                 goto end;
 122             }
 123         }
 124         /* A registration shouldn't add duplicate entries */
 125         (void)sk_ENGINE_delete_ptr(fnd->sk, e);
 126         /*
 127          * if 'setdefault', this ENGINE goes to the head of the list
 128          */
 129         if (!sk_ENGINE_push(fnd->sk, e))
 130             goto end;
 131         /* "touch" this ENGINE_PILE */
 132         fnd->uptodate = 0;
 133         if (setdefault) {
 134             if (!engine_unlocked_init(e)) {
 135                 ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INIT_FAILED);
 136                 goto end;
 137             }
 138             if (fnd->funct)
 139                 engine_unlocked_finish(fnd->funct, 0);
 140             fnd->funct = e;
 141             fnd->uptodate = 1;
 142         }
 143         nids++;
 144     }
 145     ret = 1;
 146  end:
 147     CRYPTO_THREAD_unlock(global_engine_lock);
 148     return ret;
 149 }
 150
 151 static void int_unregister_cb(ENGINE_PILE *pile, ENGINE *e)
 152 {
 153     int n;
 154     /* Iterate the 'c->sk' stack removing any occurrence of 'e' */
 155     while ((n = sk_ENGINE_find(pile->sk, e)) >= 0) {
 156         (void)sk_ENGINE_delete(pile->sk, n);
 157         pile->uptodate = 0;
 158     }
 159     if (pile->funct == e) {
 160         engine_unlocked_finish(e, 0);
 161         pile->funct = NULL;
 162     }
 163 }
 164
 165 IMPLEMENT_LHASH_DOALL_ARG(ENGINE_PILE, ENGINE);
 166
 167 void engine_table_unregister(ENGINE_TABLE **table, ENGINE *e)
 168 {
 169     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
 170         /* Can't return a value. :( */
 171         return;
 172     if (int_table_check(table, 0))
 173         lh_ENGINE_PILE_doall_ENGINE(&(*table)->piles, int_unregister_cb, e);
 174     CRYPTO_THREAD_unlock(global_engine_lock);
 175 }
 176
 177 static void int_cleanup_cb_doall(ENGINE_PILE *p)
 178 {
 179     if (p == NULL)
 180         return;
 181     sk_ENGINE_free(p->sk);
 182     if (p->funct)
 183         engine_unlocked_finish(p->funct, 0);
 184     OPENSSL_free(p);
 185 }
 186
 187 void engine_table_cleanup(ENGINE_TABLE **table)
 188 {
 189     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
 190         return;
 191     if (*table) {
 192         lh_ENGINE_PILE_doall(&(*table)->piles, int_cleanup_cb_doall);
 193         lh_ENGINE_PILE_free(&(*table)->piles);
 194         *table = NULL;
 195     }
 196     CRYPTO_THREAD_unlock(global_engine_lock);
 197 }
 198
 199 /* return a functional reference for a given 'nid' */
 200 ENGINE *ossl_engine_table_select(ENGINE_TABLE **table, int nid,
 201                                  const char *f, int l)
 202 {
 203     ENGINE *ret = NULL;
 204     ENGINE_PILE tmplate, *fnd = NULL;
 205     int initres, loop = 0;
 206
 207 #ifndef OPENSSL_NO_AUTOLOAD_CONFIG
 208     /* Load the config before trying to check if engines are available */
 209     OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL);
 210 #endif
 211
 212     if (!(*table)) {
 213         OSSL_TRACE3(ENGINE_TABLE,
 214                    "%s:%d, nid=%d, nothing registered!\n",
 215                    f, l, nid);
 216         return NULL;
 217     }
 218
 219     if (!CRYPTO_THREAD_write_lock(global_engine_lock))
 220         return NULL;
 221
 222     ERR_set_mark();
 223     /*
 224      * Check again inside the lock otherwise we could race against cleanup
 225      * operations. But don't worry about a debug printout
 226      */
 227     if (!int_table_check(table, 0))
 228         goto end;
 229     tmplate.nid = nid;
 230     fnd = lh_ENGINE_PILE_retrieve(&(*table)->piles, &tmplate);
 231     if (!fnd)
 232         goto end;
 233     if (fnd->funct && engine_unlocked_init(fnd->funct)) {
 234         OSSL_TRACE4(ENGINE_TABLE,
 235                    "%s:%d, nid=%d, using ENGINE '%s' cached\n",
 236                    f, l, nid, fnd->funct->id);
 237         ret = fnd->funct;
 238         goto end;
 239     }
 240     if (fnd->uptodate) {
 241         ret = fnd->funct;
 242         goto end;
 243     }
 244  trynext:
 245     ret = sk_ENGINE_value(fnd->sk, loop++);
 246     if (!ret) {
 247         OSSL_TRACE3(ENGINE_TABLE,
 248                     "%s:%d, nid=%d, "
 249                     "no registered implementations would initialise\n",
 250                     f, l, nid);
 251         goto end;
 252     }
 253     /* Try to initialise the ENGINE? */
 254     if ((ret->funct_ref > 0) || !(table_flags & ENGINE_TABLE_FLAG_NOINIT))
 255         initres = engine_unlocked_init(ret);
 256     else
 257         initres = 0;
 258     if (initres) {
 259         /* Update 'funct' */
 260         if ((fnd->funct != ret) && engine_unlocked_init(ret)) {
 261             /* If there was a previous default we release it. */
 262             if (fnd->funct)
 263                 engine_unlocked_finish(fnd->funct, 0);
 264             fnd->funct = ret;
 265             OSSL_TRACE4(ENGINE_TABLE,
 266                         "%s:%d, nid=%d, setting default to '%s'\n",
 267                         f, l, nid, ret->id);
 268         }
 269         OSSL_TRACE4(ENGINE_TABLE,
 270                     "%s:%d, nid=%d, using newly initialised '%s'\n",
 271                     f, l, nid, ret->id);
 272         goto end;
 273     }
 274     goto trynext;
 275  end:
 276     /*
 277      * If it failed, it is unlikely to succeed again until some future
 278      * registrations have taken place. In all cases, we cache.
 279      */
 280     if (fnd)
 281         fnd->uptodate = 1;
 282     if (ret)
 283         OSSL_TRACE4(ENGINE_TABLE,
 284                    "%s:%d, nid=%d, caching ENGINE '%s'\n",
 285                    f, l, nid, ret->id);
 286     else
 287         OSSL_TRACE3(ENGINE_TABLE,
 288                     "%s:%d, nid=%d, caching 'no matching ENGINE'\n",
 289                     f, l, nid);
 290     CRYPTO_THREAD_unlock(global_engine_lock);
 291     /*
 292      * Whatever happened, any failed init()s are not failures in this
 293      * context, so clear our error state.
 294      */
 295     ERR_pop_to_mark();
 296     return ret;
 297 }
 298
 299 /* Table enumeration */
 300
 301 static void int_dall(const ENGINE_PILE *pile, ENGINE_PILE_DOALL *dall)
 302 {
 303     dall->cb(pile->nid, pile->sk, pile->funct, dall->arg);
 304 }
 305
 306 IMPLEMENT_LHASH_DOALL_ARG_CONST(ENGINE_PILE, ENGINE_PILE_DOALL);
 307
 308 void engine_table_doall(ENGINE_TABLE *table, engine_table_doall_cb *cb,
 309                         void *arg)
 310 {
 311     ENGINE_PILE_DOALL dall;
 312     dall.cb = cb;
 313     dall.arg = arg;
 314     if (table)
 315         lh_ENGINE_PILE_doall_ENGINE_PILE_DOALL(&table->piles, int_dall, &dall);
 316 }