2 * Copyright 2001-2020 The OpenSSL Project Authors. All Rights Reserved.
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
10 #include "eng_local.h"
11 #include "internal/dso.h"
12 #include <openssl/crypto.h>
15 * Shared libraries implementing ENGINEs for use by the "dynamic" ENGINE
16 * loader should implement the hook-up functions with the following
20 DEFINE_STACK_OF_STRING()
22 /* Our ENGINE handlers */
23 static int dynamic_init(ENGINE *e);
24 static int dynamic_finish(ENGINE *e);
25 static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p,
27 /* Predeclare our context type */
28 typedef struct st_dynamic_data_ctx dynamic_data_ctx;
29 /* The implementation for the important control command */
30 static int dynamic_load(ENGINE *e, dynamic_data_ctx *ctx);
32 #define DYNAMIC_CMD_SO_PATH ENGINE_CMD_BASE
33 #define DYNAMIC_CMD_NO_VCHECK (ENGINE_CMD_BASE + 1)
34 #define DYNAMIC_CMD_ID (ENGINE_CMD_BASE + 2)
35 #define DYNAMIC_CMD_LIST_ADD (ENGINE_CMD_BASE + 3)
36 #define DYNAMIC_CMD_DIR_LOAD (ENGINE_CMD_BASE + 4)
37 #define DYNAMIC_CMD_DIR_ADD (ENGINE_CMD_BASE + 5)
38 #define DYNAMIC_CMD_LOAD (ENGINE_CMD_BASE + 6)
40 /* The constants used when creating the ENGINE */
41 static const char *engine_dynamic_id = "dynamic";
42 static const char *engine_dynamic_name = "Dynamic engine loading support";
43 static const ENGINE_CMD_DEFN dynamic_cmd_defns[] = {
46 "Specifies the path to the new ENGINE shared library",
47 ENGINE_CMD_FLAG_STRING},
48 {DYNAMIC_CMD_NO_VCHECK,
50 "Specifies to continue even if version checking fails (boolean)",
51 ENGINE_CMD_FLAG_NUMERIC},
54 "Specifies an ENGINE id name for loading",
55 ENGINE_CMD_FLAG_STRING},
56 {DYNAMIC_CMD_LIST_ADD,
58 "Whether to add a loaded ENGINE to the internal list (0=no,1=yes,2=mandatory)",
59 ENGINE_CMD_FLAG_NUMERIC},
60 {DYNAMIC_CMD_DIR_LOAD,
62 "Specifies whether to load from 'DIR_ADD' directories (0=no,1=yes,2=mandatory)",
63 ENGINE_CMD_FLAG_NUMERIC},
66 "Adds a directory from which ENGINEs can be loaded",
67 ENGINE_CMD_FLAG_STRING},
70 "Load up the ENGINE specified by other settings",
71 ENGINE_CMD_FLAG_NO_INPUT},
76 * Loading code stores state inside the ENGINE structure via the "ex_data"
77 * element. We load all our state into a single structure and use that as a
78 * single context in the "ex_data" stack.
80 struct st_dynamic_data_ctx {
81 /* The DSO object we load that supplies the ENGINE code */
84 * The function pointer to the version checking shared library function
86 dynamic_v_check_fn v_check;
88 * The function pointer to the engine-binding shared library function
90 dynamic_bind_engine bind_engine;
91 /* The default name/path for loading the shared library */
92 char *DYNAMIC_LIBNAME;
93 /* Whether to continue loading on a version check failure */
95 /* If non-NULL, stipulates the 'id' of the ENGINE to be loaded */
98 * If non-zero, a successfully loaded ENGINE should be added to the
99 * internal ENGINE list. If 2, the add must succeed or the entire load
103 /* The symbol name for the version checking function */
104 const char *DYNAMIC_F1;
105 /* The symbol name for the "initialise ENGINE structure" function */
106 const char *DYNAMIC_F2;
108 * Whether to never use 'dirs', use 'dirs' as a fallback, or only use
109 * 'dirs' for loading. Default is to use 'dirs' as a fallback.
112 /* A stack of directories from which ENGINEs could be loaded */
113 STACK_OF(OPENSSL_STRING) *dirs;
117 * This is the "ex_data" index we obtain and reserve for use with our context
120 static int dynamic_ex_data_idx = -1;
122 static void int_free_str(char *s)
128 * Because our ex_data element may or may not get allocated depending on
129 * whether a "first-use" occurs before the ENGINE is freed, we have a memory
130 * leak problem to solve. We can't declare a "new" handler for the ex_data as
131 * we don't want a dynamic_data_ctx in *all* ENGINE structures of all types
132 * (this is a bug in the design of CRYPTO_EX_DATA). As such, we just declare
133 * a "free" handler and that will get called if an ENGINE is being destroyed
134 * and there was an ex_data element corresponding to our context type.
136 static void dynamic_data_ctx_free_func(void *parent, void *ptr,
137 CRYPTO_EX_DATA *ad, int idx, long argl,
141 dynamic_data_ctx *ctx = (dynamic_data_ctx *)ptr;
142 DSO_free(ctx->dynamic_dso);
143 OPENSSL_free(ctx->DYNAMIC_LIBNAME);
144 OPENSSL_free(ctx->engine_id);
145 sk_OPENSSL_STRING_pop_free(ctx->dirs, int_free_str);
151 * Construct the per-ENGINE context. We create it blindly and then use a lock
152 * to check for a race - if so, all but one of the threads "racing" will have
153 * wasted their time. The alternative involves creating everything inside the
154 * lock which is far worse.
156 static int dynamic_set_data_ctx(ENGINE *e, dynamic_data_ctx **ctx)
158 dynamic_data_ctx *c = OPENSSL_zalloc(sizeof(*c));
162 ENGINEerr(ENGINE_F_DYNAMIC_SET_DATA_CTX, ERR_R_MALLOC_FAILURE);
165 c->dirs = sk_OPENSSL_STRING_new_null();
166 if (c->dirs == NULL) {
167 ENGINEerr(ENGINE_F_DYNAMIC_SET_DATA_CTX, ERR_R_MALLOC_FAILURE);
171 c->DYNAMIC_F1 = "v_check";
172 c->DYNAMIC_F2 = "bind_engine";
174 CRYPTO_THREAD_write_lock(global_engine_lock);
175 if ((*ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e,
176 dynamic_ex_data_idx))
178 /* Good, we're the first */
179 ret = ENGINE_set_ex_data(e, dynamic_ex_data_idx, c);
185 CRYPTO_THREAD_unlock(global_engine_lock);
187 * If we lost the race to set the context, c is non-NULL and *ctx is the
188 * context of the thread that won.
191 sk_OPENSSL_STRING_free(c->dirs);
197 * This function retrieves the context structure from an ENGINE's "ex_data",
198 * or if it doesn't exist yet, sets it up.
200 static dynamic_data_ctx *dynamic_get_data_ctx(ENGINE *e)
202 dynamic_data_ctx *ctx;
203 if (dynamic_ex_data_idx < 0) {
205 * Create and register the ENGINE ex_data, and associate our "free"
206 * function with it to ensure any allocated contexts get freed when
207 * an ENGINE goes underground.
209 int new_idx = ENGINE_get_ex_new_index(0, NULL, NULL, NULL,
210 dynamic_data_ctx_free_func);
212 ENGINEerr(ENGINE_F_DYNAMIC_GET_DATA_CTX, ENGINE_R_NO_INDEX);
215 CRYPTO_THREAD_write_lock(global_engine_lock);
216 /* Avoid a race by checking again inside this lock */
217 if (dynamic_ex_data_idx < 0) {
218 /* Good, someone didn't beat us to it */
219 dynamic_ex_data_idx = new_idx;
222 CRYPTO_THREAD_unlock(global_engine_lock);
224 * In theory we could "give back" the index here if (new_idx>-1), but
225 * it's not possible and wouldn't gain us much if it were.
228 ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e, dynamic_ex_data_idx);
229 /* Check if the context needs to be created */
230 if ((ctx == NULL) && !dynamic_set_data_ctx(e, &ctx))
231 /* "set_data" will set errors if necessary */
236 static ENGINE *engine_dynamic(void)
238 ENGINE *ret = ENGINE_new();
241 if (!ENGINE_set_id(ret, engine_dynamic_id) ||
242 !ENGINE_set_name(ret, engine_dynamic_name) ||
243 !ENGINE_set_init_function(ret, dynamic_init) ||
244 !ENGINE_set_finish_function(ret, dynamic_finish) ||
245 !ENGINE_set_ctrl_function(ret, dynamic_ctrl) ||
246 !ENGINE_set_flags(ret, ENGINE_FLAGS_BY_ID_COPY) ||
247 !ENGINE_set_cmd_defns(ret, dynamic_cmd_defns)) {
254 void engine_load_dynamic_int(void)
256 ENGINE *toadd = engine_dynamic();
261 * If the "add" worked, it gets a structural reference. So either way, we
262 * release our just-created reference.
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).
273 static int dynamic_init(ENGINE *e)
276 * We always return failure - the "dynamic" engine itself can't be used
282 static int dynamic_finish(ENGINE *e)
285 * This should never be called on account of "dynamic_init" always
291 static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
293 dynamic_data_ctx *ctx = dynamic_get_data_ctx(e);
297 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_NOT_LOADED);
300 initialised = ((ctx->dynamic_dso == NULL) ? 0 : 1);
301 /* All our control commands require the ENGINE to be uninitialised */
303 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_ALREADY_LOADED);
307 case DYNAMIC_CMD_SO_PATH:
308 /* a NULL 'p' or a string of zero-length is the same thing */
309 if (p && (strlen((const char *)p) < 1))
311 OPENSSL_free(ctx->DYNAMIC_LIBNAME);
313 ctx->DYNAMIC_LIBNAME = OPENSSL_strdup(p);
315 ctx->DYNAMIC_LIBNAME = NULL;
316 return (ctx->DYNAMIC_LIBNAME ? 1 : 0);
317 case DYNAMIC_CMD_NO_VCHECK:
318 ctx->no_vcheck = ((i == 0) ? 0 : 1);
321 /* a NULL 'p' or a string of zero-length is the same thing */
322 if (p && (strlen((const char *)p) < 1))
324 OPENSSL_free(ctx->engine_id);
326 ctx->engine_id = OPENSSL_strdup(p);
328 ctx->engine_id = NULL;
329 return (ctx->engine_id ? 1 : 0);
330 case DYNAMIC_CMD_LIST_ADD:
331 if ((i < 0) || (i > 2)) {
332 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_INVALID_ARGUMENT);
335 ctx->list_add_value = (int)i;
337 case DYNAMIC_CMD_LOAD:
338 return dynamic_load(e, ctx);
339 case DYNAMIC_CMD_DIR_LOAD:
340 if ((i < 0) || (i > 2)) {
341 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_INVALID_ARGUMENT);
344 ctx->dir_load = (int)i;
346 case DYNAMIC_CMD_DIR_ADD:
347 /* a NULL 'p' or a string of zero-length is the same thing */
348 if (p == NULL || (strlen((const char *)p) < 1)) {
349 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_INVALID_ARGUMENT);
353 char *tmp_str = OPENSSL_strdup(p);
354 if (tmp_str == NULL) {
355 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ERR_R_MALLOC_FAILURE);
358 if (!sk_OPENSSL_STRING_push(ctx->dirs, tmp_str)) {
359 OPENSSL_free(tmp_str);
360 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ERR_R_MALLOC_FAILURE);
368 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_CTRL_COMMAND_NOT_IMPLEMENTED);
372 static int int_load(dynamic_data_ctx *ctx)
375 /* Unless told not to, try a direct load */
376 if ((ctx->dir_load != 2) && (DSO_load(ctx->dynamic_dso,
377 ctx->DYNAMIC_LIBNAME, NULL,
380 /* If we're not allowed to use 'dirs' or we have none, fail */
381 if (!ctx->dir_load || (num = sk_OPENSSL_STRING_num(ctx->dirs)) < 1)
383 for (loop = 0; loop < num; loop++) {
384 const char *s = sk_OPENSSL_STRING_value(ctx->dirs, loop);
385 char *merge = DSO_merge(ctx->dynamic_dso, ctx->DYNAMIC_LIBNAME, s);
388 if (DSO_load(ctx->dynamic_dso, merge, NULL, 0)) {
389 /* Found what we're looking for */
398 static int dynamic_load(ENGINE *e, dynamic_data_ctx *ctx)
403 if (ctx->dynamic_dso == NULL)
404 ctx->dynamic_dso = DSO_new();
405 if (ctx->dynamic_dso == NULL)
407 if (!ctx->DYNAMIC_LIBNAME) {
410 DSO_ctrl(ctx->dynamic_dso, DSO_CTRL_SET_FLAGS,
411 DSO_FLAG_NAME_TRANSLATION_EXT_ONLY, NULL);
412 ctx->DYNAMIC_LIBNAME =
413 DSO_convert_filename(ctx->dynamic_dso, ctx->engine_id);
415 if (!int_load(ctx)) {
416 ENGINEerr(ENGINE_F_DYNAMIC_LOAD, ENGINE_R_DSO_NOT_FOUND);
417 DSO_free(ctx->dynamic_dso);
418 ctx->dynamic_dso = NULL;
421 /* We have to find a bind function otherwise it'll always end badly */
424 (dynamic_bind_engine) DSO_bind_func(ctx->dynamic_dso,
426 ctx->bind_engine = NULL;
427 DSO_free(ctx->dynamic_dso);
428 ctx->dynamic_dso = NULL;
429 ENGINEerr(ENGINE_F_DYNAMIC_LOAD, ENGINE_R_DSO_FAILURE);
432 /* Do we perform version checking? */
433 if (!ctx->no_vcheck) {
434 unsigned long vcheck_res = 0;
436 * Now we try to find a version checking function and decide how to
437 * cope with failure if/when it fails.
440 (dynamic_v_check_fn) DSO_bind_func(ctx->dynamic_dso,
443 vcheck_res = ctx->v_check(OSSL_DYNAMIC_VERSION);
445 * We fail if the version checker veto'd the load *or* if it is
446 * deferring to us (by returning its version) and we think it is too
449 if (vcheck_res < OSSL_DYNAMIC_OLDEST) {
451 ctx->bind_engine = NULL;
453 DSO_free(ctx->dynamic_dso);
454 ctx->dynamic_dso = NULL;
455 ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
456 ENGINE_R_VERSION_INCOMPATIBILITY);
461 * First binary copy the ENGINE structure so that we can roll back if the
464 memcpy(&cpy, e, sizeof(ENGINE));
466 * Provide the ERR, "ex_data", memory, and locking callbacks so the
467 * loaded library uses our state rather than its own. FIXME: As noted in
468 * engine.h, much of this would be simplified if each area of code
469 * provided its own "summary" structure of all related callbacks. It
470 * would also increase opaqueness.
472 fns.static_state = ENGINE_get_static_state();
473 CRYPTO_get_mem_functions(&fns.mem_fns.malloc_fn, &fns.mem_fns.realloc_fn,
474 &fns.mem_fns.free_fn);
476 * Now that we've loaded the dynamic engine, make sure no "dynamic"
477 * ENGINE elements will show through.
479 engine_set_all_null(e);
481 /* Try to bind the ENGINE onto our own ENGINE structure */
482 if (!ctx->bind_engine(e, ctx->engine_id, &fns)) {
483 ctx->bind_engine = NULL;
485 DSO_free(ctx->dynamic_dso);
486 ctx->dynamic_dso = NULL;
487 ENGINEerr(ENGINE_F_DYNAMIC_LOAD, ENGINE_R_INIT_FAILED);
488 /* Copy the original ENGINE structure back */
489 memcpy(e, &cpy, sizeof(ENGINE));
492 /* Do we try to add this ENGINE to the internal list too? */
493 if (ctx->list_add_value > 0) {
494 if (!ENGINE_add(e)) {
495 /* Do we tolerate this or fail? */
496 if (ctx->list_add_value > 1) {
498 * Fail - NB: By this time, it's too late to rollback, and
499 * trying to do so allows the bind_engine() code to have
500 * created leaks. We just have to fail where we are, after
501 * the ENGINE has changed.
503 ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
504 ENGINE_R_CONFLICTING_ENGINE_ID);