crypto/engine/eng_dyn.c

   1 /* crypto/engine/eng_dyn.c */
   2 /* Written by Geoff Thorpe (geoff@geoffthorpe.net) for the OpenSSL
   3  * project 2001.
   4  */
   5 /* ====================================================================
   6  * Copyright (c) 1999-2001 The OpenSSL Project.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  *
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in
  17  *    the documentation and/or other materials provided with the
  18  *    distribution.
  19  *
  20  * 3. All advertising materials mentioning features or use of this
  21  *    software must display the following acknowledgment:
  22  *    "This product includes software developed by the OpenSSL Project
  23  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  24  *
  25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  26  *    endorse or promote products derived from this software without
  27  *    prior written permission. For written permission, please contact
  28  *    licensing@OpenSSL.org.
  29  *
  30  * 5. Products derived from this software may not be called "OpenSSL"
  31  *    nor may "OpenSSL" appear in their names without prior written
  32  *    permission of the OpenSSL Project.
  33  *
  34  * 6. Redistributions of any form whatsoever must retain the following
  35  *    acknowledgment:
  36  *    "This product includes software developed by the OpenSSL Project
  37  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  38  *
  39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  50  * OF THE POSSIBILITY OF SUCH DAMAGE.
  51  * ====================================================================
  52  *
  53  * This product includes cryptographic software written by Eric Young
  54  * (eay@cryptsoft.com).  This product includes software written by Tim
  55  * Hudson (tjh@cryptsoft.com).
  56  *
  57  */
  58
  59
  60 #include <stdio.h>
  61 #include <openssl/crypto.h>
  62 #include "cryptlib.h"
  63 #include "eng_int.h"
  64 #include <openssl/engine.h>
  65 #include <openssl/dso.h>
  66
  67 /* Shared libraries implementing ENGINEs for use by the "dynamic" ENGINE loader
  68  * should implement the hook-up functions with the following prototypes. */
  69
  70 /* Our ENGINE handlers */
  71 static int dynamic_init(ENGINE *e);
  72 static int dynamic_finish(ENGINE *e);
  73 static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)());
  74 /* Predeclare our context type */
  75 typedef struct st_dynamic_data_ctx dynamic_data_ctx;
  76 /* The implementation for the important control command */
  77 static int dynamic_load(ENGINE *e, dynamic_data_ctx *ctx);
  78
  79 #define DYNAMIC_CMD_SO_PATH             ENGINE_CMD_BASE
  80 #define DYNAMIC_CMD_NO_VCHECK           (ENGINE_CMD_BASE + 1)
  81 #define DYNAMIC_CMD_ENGINE_ID           (ENGINE_CMD_BASE + 2)
  82 #define DYNAMIC_CMD_LIST_ADD            (ENGINE_CMD_BASE + 3)
  83 #define DYNAMIC_CMD_LOAD                (ENGINE_CMD_BASE + 4)
  84
  85 /* The constants used when creating the ENGINE */
  86 static const char *engine_dynamic_id = "dynamic";
  87 static const char *engine_dynamic_name = "Dynamic engine loading support";
  88 static const ENGINE_CMD_DEFN dynamic_cmd_defns[] = {
  89         {DYNAMIC_CMD_SO_PATH,
  90                 "SO_PATH",
  91                 "Specifies the path to the new ENGINE shared library",
  92                 ENGINE_CMD_FLAG_STRING},
  93         {DYNAMIC_CMD_NO_VCHECK,
  94                 "NO_VCHECK",
  95                 "Specifies to continue even if version checking fails (boolean)",
  96                 ENGINE_CMD_FLAG_NUMERIC},
  97         {DYNAMIC_CMD_ENGINE_ID,
  98                 "ENGINE_ID",
  99                 "Specifies an ENGINE id name for loading",
 100                 ENGINE_CMD_FLAG_STRING},
 101         {DYNAMIC_CMD_LIST_ADD,
 102                 "LIST_ADD",
 103                 "Whether to add a loaded ENGINE to the internal list (0=no,1=yes,2=mandatory)",
 104                 ENGINE_CMD_FLAG_NUMERIC},
 105         {DYNAMIC_CMD_LOAD,
 106                 "LOAD",
 107                 "Load up the ENGINE specified by other settings",
 108                 ENGINE_CMD_FLAG_NO_INPUT},
 109         {0, NULL, NULL, 0}
 110         };
 111
 112 /* Loading code stores state inside the ENGINE structure via the "ex_data"
 113  * element. We load all our state into a single structure and use that as a
 114  * single context in the "ex_data" stack. */
 115 struct st_dynamic_data_ctx
 116         {
 117         /* The DSO object we load that supplies the ENGINE code */
 118         DSO *dynamic_dso;
 119         /* The function pointer to the version checking shared library function */
 120         dynamic_v_check_fn v_check;
 121         /* The function pointer to the engine-binding shared library function */
 122         dynamic_bind_engine bind_engine;
 123         /* The default name/path for loading the shared library */
 124         const char *DYNAMIC_LIBNAME;
 125         /* Whether to continue loading on a version check failure */
 126         int no_vcheck;
 127         /* If non-NULL, stipulates the 'id' of the ENGINE to be loaded */
 128         const char *engine_id;
 129         /* If non-zero, a successfully loaded ENGINE should be added to the internal
 130          * ENGINE list. If 2, the add must succeed or the entire load should fail. */
 131         int list_add_value;
 132         /* The symbol name for the version checking function */
 133         const char *DYNAMIC_F1;
 134         /* The symbol name for the "initialise ENGINE structure" function */
 135         const char *DYNAMIC_F2;
 136         };
 137
 138 /* This is the "ex_data" index we obtain and reserve for use with our context
 139  * structure. */
 140 static int dynamic_ex_data_idx = -1;
 141
 142 /* Because our ex_data element may or may not get allocated depending on whether
 143  * a "first-use" occurs before the ENGINE is freed, we have a memory leak
 144  * problem to solve. We can't declare a "new" handler for the ex_data as we
 145  * don't want a dynamic_data_ctx in *all* ENGINE structures of all types (this
 146  * is a bug in the design of CRYPTO_EX_DATA). As such, we just declare a "free"
 147  * handler and that will get called if an ENGINE is being destroyed and there
 148  * was an ex_data element corresponding to our context type. */
 149 static void dynamic_data_ctx_free_func(void *parent, void *ptr,
 150                         CRYPTO_EX_DATA *ad, int idx, long argl, void *argp)
 151         {
 152         if(ptr)
 153                 {
 154                 dynamic_data_ctx *ctx = (dynamic_data_ctx *)ptr;
 155                 if(ctx->dynamic_dso)
 156                         DSO_free(ctx->dynamic_dso);
 157                 OPENSSL_free(ctx);
 158                 }
 159         }
 160
 161 /* Construct the per-ENGINE context. We create it blindly and then use a lock to
 162  * check for a race - if so, all but one of the threads "racing" will have
 163  * wasted their time. The alternative involves creating everything inside the
 164  * lock which is far worse. */
 165 static int dynamic_set_data_ctx(ENGINE *e, dynamic_data_ctx **ctx)
 166         {
 167         dynamic_data_ctx *c;
 168         c = OPENSSL_malloc(sizeof(dynamic_data_ctx));
 169         if(!ctx)
 170                 {
 171                 ENGINEerr(ENGINE_F_SET_DATA_CTX,ERR_R_MALLOC_FAILURE);
 172                 return 0;
 173                 }
 174         memset(c, 0, sizeof(dynamic_data_ctx));
 175         c->dynamic_dso = NULL;
 176         c->v_check = NULL;
 177         c->bind_engine = NULL;
 178         c->DYNAMIC_LIBNAME = NULL;
 179         c->no_vcheck = 0;
 180         c->engine_id = NULL;
 181         c->list_add_value = 0;
 182         c->DYNAMIC_F1 = "v_check";
 183         c->DYNAMIC_F2 = "bind_engine";
 184         CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
 185         if((*ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e,
 186                                 dynamic_ex_data_idx)) == NULL)
 187                 {
 188                 /* Good, we're the first */
 189                 ENGINE_set_ex_data(e, dynamic_ex_data_idx, c);
 190                 *ctx = c;
 191                 c = NULL;
 192                 }
 193         CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
 194         /* If we lost the race to set the context, c is non-NULL and *ctx is the
 195          * context of the thread that won. */
 196         if(c)
 197                 OPENSSL_free(c);
 198         return 1;
 199         }
 200
 201 /* This function retrieves the context structure from an ENGINE's "ex_data", or
 202  * if it doesn't exist yet, sets it up. */
 203 static dynamic_data_ctx *dynamic_get_data_ctx(ENGINE *e)
 204         {
 205         dynamic_data_ctx *ctx;
 206         if(dynamic_ex_data_idx < 0)
 207                 {
 208                 /* Create and register the ENGINE ex_data, and associate our
 209                  * "free" function with it to ensure any allocated contexts get
 210                  * freed when an ENGINE goes underground. */
 211                 int new_idx = ENGINE_get_ex_new_index(0, NULL, NULL, NULL,
 212                                         dynamic_data_ctx_free_func);
 213                 if(new_idx == -1)
 214                         {
 215                         ENGINEerr(ENGINE_F_DYNAMIC_GET_DATA_CTX,ENGINE_R_NO_INDEX);
 216                         return NULL;
 217                         }
 218                 CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
 219                 /* Avoid a race by checking again inside this lock */
 220                 if(dynamic_ex_data_idx < 0)
 221                         {
 222                         /* Good, someone didn't beat us to it */
 223                         dynamic_ex_data_idx = new_idx;
 224                         new_idx = -1;
 225                         }
 226                 CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
 227                 /* In theory we could "give back" the index here if
 228                  * (new_idx>-1), but it's not possible and wouldn't gain us much
 229                  * if it were. */
 230                 }
 231         ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e, dynamic_ex_data_idx);
 232         /* Check if the context needs to be created */
 233         if((ctx == NULL) && !dynamic_set_data_ctx(e, &ctx))
 234                 /* "set_data" will set errors if necessary */
 235                 return NULL;
 236         return ctx;
 237         }
 238
 239 static ENGINE *engine_dynamic(void)
 240         {
 241         ENGINE *ret = ENGINE_new();
 242         if(!ret)
 243                 return NULL;
 244         if(!ENGINE_set_id(ret, engine_dynamic_id) ||
 245                         !ENGINE_set_name(ret, engine_dynamic_name) ||
 246                         !ENGINE_set_init_function(ret, dynamic_init) ||
 247                         !ENGINE_set_finish_function(ret, dynamic_finish) ||
 248                         !ENGINE_set_ctrl_function(ret, dynamic_ctrl) ||
 249                         !ENGINE_set_flags(ret, ENGINE_FLAGS_BY_ID_COPY) ||
 250                         !ENGINE_set_cmd_defns(ret, dynamic_cmd_defns))
 251                 {
 252                 ENGINE_free(ret);
 253                 return NULL;
 254                 }
 255         return ret;
 256         }
 257
 258 void ENGINE_load_dynamic(void)
 259         {
 260         ENGINE *toadd = engine_dynamic();
 261         if(!toadd) return;
 262         ENGINE_add(toadd);
 263         /* If the "add" worked, it gets a structural reference. So either way,
 264          * we release our just-created reference. */
 265         ENGINE_free(toadd);
 266         /* If the "add" didn't work, it was probably a conflict because it was
 267          * already added (eg. someone calling ENGINE_load_blah then calling
 268          * ENGINE_load_builtin_engines() perhaps). */
 269         ERR_clear_error();
 270         }
 271
 272 static int dynamic_init(ENGINE *e)
 273         {
 274         /* We always return failure - the "dyanamic" engine itself can't be used
 275          * for anything. */
 276         return 0;
 277         }
 278
 279 static int dynamic_finish(ENGINE *e)
 280         {
 281         /* This should never be called on account of "dynamic_init" always
 282          * failing. */
 283         return 0;
 284         }
 285
 286 static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)())
 287         {
 288         dynamic_data_ctx *ctx = dynamic_get_data_ctx(e);
 289         int initialised;
 290
 291         if(!ctx)
 292                 {
 293                 ENGINEerr(ENGINE_F_DYNAMIC_CTRL,ENGINE_R_NOT_LOADED);
 294                 return 0;
 295                 }
 296         initialised = ((ctx->dynamic_dso == NULL) ? 0 : 1);
 297         /* All our control commands require the ENGINE to be uninitialised */
 298         if(initialised)
 299                 {
 300                 ENGINEerr(ENGINE_F_DYNAMIC_CTRL,
 301                         ENGINE_R_ALREADY_LOADED);
 302                 return 0;
 303                 }
 304         switch(cmd)
 305                 {
 306         case DYNAMIC_CMD_SO_PATH:
 307                 /* a NULL 'p' or a string of zero-length is the same thing */
 308                 if(p && (strlen((const char *)p) < 1))
 309                         p = NULL;
 310                 ctx->DYNAMIC_LIBNAME = (const char *)p;
 311                 return 1;
 312         case DYNAMIC_CMD_NO_VCHECK:
 313                 ctx->no_vcheck = ((i == 0) ? 0 : 1);
 314                 return 1;
 315         case DYNAMIC_CMD_ENGINE_ID:
 316                 /* a NULL 'p' or a string of zero-length is the same thing */
 317                 if(p && (strlen((const char *)p) < 1))
 318                         p = NULL;
 319                 ctx->engine_id = (const char *)p;
 320                 return 1;
 321         case DYNAMIC_CMD_LIST_ADD:
 322                 if((i < 0) || (i > 2))
 323                         {
 324                         ENGINEerr(ENGINE_F_DYNAMIC_CTRL,
 325                                 ENGINE_R_INVALID_ARGUMENT);
 326                         return 0;
 327                         }
 328                 ctx->list_add_value = (int)i;
 329                 return 1;
 330         case DYNAMIC_CMD_LOAD:
 331                 return dynamic_load(e, ctx);
 332         default:
 333                 break;
 334                 }
 335         ENGINEerr(ENGINE_F_DYNAMIC_CTRL,ENGINE_R_CTRL_COMMAND_NOT_IMPLEMENTED);
 336         return 0;
 337         }
 338
 339 static int dynamic_load(ENGINE *e, dynamic_data_ctx *ctx)
 340         {
 341         ENGINE cpy;
 342         dynamic_fns fns;
 343
 344         if(!ctx->DYNAMIC_LIBNAME || ((ctx->dynamic_dso = DSO_load(NULL,
 345                                 ctx->DYNAMIC_LIBNAME, NULL, 0)) == NULL))
 346                 {
 347                 ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
 348                         ENGINE_R_DSO_NOT_FOUND);
 349                 return 0;
 350                 }
 351         /* We have to find a bind function otherwise it'll always end badly */
 352         if(!(ctx->bind_engine = (dynamic_bind_engine)DSO_bind_func(
 353                                         ctx->dynamic_dso, ctx->DYNAMIC_F2)))
 354                 {
 355                 ctx->bind_engine = NULL;
 356                 DSO_free(ctx->dynamic_dso);
 357                 ctx->dynamic_dso = NULL;
 358                 ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
 359                         ENGINE_R_DSO_FAILURE);
 360                 return 0;
 361                 }
 362         /* Do we perform version checking? */
 363         if(!ctx->no_vcheck)
 364                 {
 365                 unsigned long vcheck_res = 0;
 366                 /* Now we try to find a version checking function and decide how
 367                  * to cope with failure if/when it fails. */
 368                 ctx->v_check = (dynamic_v_check_fn)DSO_bind_func(
 369                                 ctx->dynamic_dso, ctx->DYNAMIC_F1);
 370                 if(ctx->v_check)
 371                         vcheck_res = ctx->v_check(OSSL_DYNAMIC_VERSION);
 372                 /* We fail if the version checker veto'd the load *or* if it is
 373                  * deferring to us (by returning its version) and we think it is
 374                  * too old. */
 375                 if(vcheck_res < OSSL_DYNAMIC_OLDEST)
 376                         {
 377                         /* Fail */
 378                         ctx->bind_engine = NULL;
 379                         ctx->v_check = NULL;
 380                         DSO_free(ctx->dynamic_dso);
 381                         ctx->dynamic_dso = NULL;
 382                         ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
 383                                 ENGINE_R_VERSION_INCOMPATIBILITY);
 384                         return 0;
 385                         }
 386                 }
 387         /* First binary copy the ENGINE structure so that we can roll back if
 388          * the hand-over fails */
 389         memcpy(&cpy, e, sizeof(ENGINE));
 390         /* Provide the ERR, "ex_data", memory, and locking callbacks so the
 391          * loaded library uses our state rather than its own. FIXME: As noted in
 392          * engine.h, much of this would be simplified if each area of code
 393          * provided its own "summary" structure of all related callbacks. It
 394          * would also increase opaqueness. */
 395         fns.err_fns = ERR_get_implementation();
 396         fns.ex_data_fns = CRYPTO_get_ex_data_implementation();
 397         CRYPTO_get_mem_functions(&fns.mem_fns.malloc_cb,
 398                                 &fns.mem_fns.realloc_cb,
 399                                 &fns.mem_fns.free_cb);
 400         fns.lock_fns.lock_locking_cb = CRYPTO_get_locking_callback();
 401         fns.lock_fns.lock_add_lock_cb = CRYPTO_get_add_lock_callback();
 402         fns.lock_fns.dynlock_create_cb = CRYPTO_get_dynlock_create_callback();
 403         fns.lock_fns.dynlock_lock_cb = CRYPTO_get_dynlock_lock_callback();
 404         fns.lock_fns.dynlock_destroy_cb = CRYPTO_get_dynlock_destroy_callback();
 405         /* Try to bind the ENGINE onto our own ENGINE structure */
 406         if(!ctx->bind_engine(e, ctx->engine_id, &fns))
 407                 {
 408                 ctx->bind_engine = NULL;
 409                 ctx->v_check = NULL;
 410                 DSO_free(ctx->dynamic_dso);
 411                 ctx->dynamic_dso = NULL;
 412                 ENGINEerr(ENGINE_F_DYNAMIC_LOAD,ENGINE_R_INIT_FAILED);
 413                 /* Copy the original ENGINE structure back */
 414                 memcpy(e, &cpy, sizeof(ENGINE));
 415                 return 0;
 416                 }
 417         /* Do we try to add this ENGINE to the internal list too? */
 418         if(ctx->list_add_value > 0)
 419                 {
 420                 if(!ENGINE_add(e))
 421                         {
 422                         /* Do we tolerate this or fail? */
 423                         if(ctx->list_add_value > 1)
 424                                 {
 425                                 /* Fail - NB: By this time, it's too late to
 426                                  * rollback, and trying to do so allows the
 427                                  * bind_engine() code to have created leaks. We
 428                                  * just have to fail where we are, after the
 429                                  * ENGINE has changed. */
 430                                 ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
 431                                         ENGINE_R_CONFLICTING_ENGINE_ID);
 432                                 return 0;
 433                                 }
 434                         /* Tolerate */
 435                         ERR_clear_error();
 436                         }
 437                 }
 438         return 1;
 439         }