1/*
2 * Copyright 2001-2016 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 "eng_local.h"
11#include "internal/dso.h"
12#include <openssl/crypto.h>
13
14/*
15 * Shared libraries implementing ENGINEs for use by the "dynamic" ENGINE
16 * loader should implement the hook-up functions with the following
17 * prototypes.
18 */
19
20/* Our ENGINE handlers */
21static int dynamic_init(ENGINE *e);
22static int dynamic_finish(ENGINE *e);
23static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p,
24 void (*f) (void));
25/* Predeclare our context type */
26typedef struct st_dynamic_data_ctx dynamic_data_ctx;
27/* The implementation for the important control command */
28static int dynamic_load(ENGINE *e, dynamic_data_ctx *ctx);
29
30#define DYNAMIC_CMD_SO_PATH ENGINE_CMD_BASE
31#define DYNAMIC_CMD_NO_VCHECK (ENGINE_CMD_BASE + 1)
32#define DYNAMIC_CMD_ID (ENGINE_CMD_BASE + 2)
33#define DYNAMIC_CMD_LIST_ADD (ENGINE_CMD_BASE + 3)
34#define DYNAMIC_CMD_DIR_LOAD (ENGINE_CMD_BASE + 4)
35#define DYNAMIC_CMD_DIR_ADD (ENGINE_CMD_BASE + 5)
36#define DYNAMIC_CMD_LOAD (ENGINE_CMD_BASE + 6)
37
38/* The constants used when creating the ENGINE */
39static const char *engine_dynamic_id = "dynamic";
40static const char *engine_dynamic_name = "Dynamic engine loading support";
41static const ENGINE_CMD_DEFN dynamic_cmd_defns[] = {
42 {DYNAMIC_CMD_SO_PATH,
43 "SO_PATH",
44 "Specifies the path to the new ENGINE shared library",
45 ENGINE_CMD_FLAG_STRING},
46 {DYNAMIC_CMD_NO_VCHECK,
47 "NO_VCHECK",
48 "Specifies to continue even if version checking fails (boolean)",
49 ENGINE_CMD_FLAG_NUMERIC},
50 {DYNAMIC_CMD_ID,
51 "ID",
52 "Specifies an ENGINE id name for loading",
53 ENGINE_CMD_FLAG_STRING},
54 {DYNAMIC_CMD_LIST_ADD,
55 "LIST_ADD",
56 "Whether to add a loaded ENGINE to the internal list (0=no,1=yes,2=mandatory)",
57 ENGINE_CMD_FLAG_NUMERIC},
58 {DYNAMIC_CMD_DIR_LOAD,
59 "DIR_LOAD",
60 "Specifies whether to load from 'DIR_ADD' directories (0=no,1=yes,2=mandatory)",
61 ENGINE_CMD_FLAG_NUMERIC},
62 {DYNAMIC_CMD_DIR_ADD,
63 "DIR_ADD",
64 "Adds a directory from which ENGINEs can be loaded",
65 ENGINE_CMD_FLAG_STRING},
66 {DYNAMIC_CMD_LOAD,
67 "LOAD",
68 "Load up the ENGINE specified by other settings",
69 ENGINE_CMD_FLAG_NO_INPUT},
70 {0, NULL, NULL, 0}
71};
72
73/*
74 * Loading code stores state inside the ENGINE structure via the "ex_data"
75 * element. We load all our state into a single structure and use that as a
76 * single context in the "ex_data" stack.
77 */
78struct st_dynamic_data_ctx {
79 /* The DSO object we load that supplies the ENGINE code */
80 DSO *dynamic_dso;
81 /*
82 * The function pointer to the version checking shared library function
83 */
84 dynamic_v_check_fn v_check;
85 /*
86 * The function pointer to the engine-binding shared library function
87 */
88 dynamic_bind_engine bind_engine;
89 /* The default name/path for loading the shared library */
90 char *DYNAMIC_LIBNAME;
91 /* Whether to continue loading on a version check failure */
92 int no_vcheck;
93 /* If non-NULL, stipulates the 'id' of the ENGINE to be loaded */
94 char *engine_id;
95 /*
96 * If non-zero, a successfully loaded ENGINE should be added to the
97 * internal ENGINE list. If 2, the add must succeed or the entire load
98 * should fail.
99 */
100 int list_add_value;
101 /* The symbol name for the version checking function */
102 const char *DYNAMIC_F1;
103 /* The symbol name for the "initialise ENGINE structure" function */
104 const char *DYNAMIC_F2;
105 /*
106 * Whether to never use 'dirs', use 'dirs' as a fallback, or only use
107 * 'dirs' for loading. Default is to use 'dirs' as a fallback.
108 */
109 int dir_load;
110 /* A stack of directories from which ENGINEs could be loaded */
111 STACK_OF(OPENSSL_STRING) *dirs;
112};
113
114/*
115 * This is the "ex_data" index we obtain and reserve for use with our context
116 * structure.
117 */
118static int dynamic_ex_data_idx = -1;
119
120static void int_free_str(char *s)
121{
122 OPENSSL_free(s);
123}
124
125/*
126 * Because our ex_data element may or may not get allocated depending on
127 * whether a "first-use" occurs before the ENGINE is freed, we have a memory
128 * leak problem to solve. We can't declare a "new" handler for the ex_data as
129 * we don't want a dynamic_data_ctx in *all* ENGINE structures of all types
130 * (this is a bug in the design of CRYPTO_EX_DATA). As such, we just declare
131 * a "free" handler and that will get called if an ENGINE is being destroyed
132 * and there was an ex_data element corresponding to our context type.
133 */
134static void dynamic_data_ctx_free_func(void *parent, void *ptr,
135 CRYPTO_EX_DATA *ad, int idx, long argl,
136 void *argp)
137{
138 if (ptr) {
139 dynamic_data_ctx *ctx = (dynamic_data_ctx *)ptr;
140 DSO_free(ctx->dynamic_dso);
141 OPENSSL_free(ctx->DYNAMIC_LIBNAME);
142 OPENSSL_free(ctx->engine_id);
143 sk_OPENSSL_STRING_pop_free(ctx->dirs, int_free_str);
144 OPENSSL_free(ctx);
145 }
146}
147
148/*
149 * Construct the per-ENGINE context. We create it blindly and then use a lock
150 * to check for a race - if so, all but one of the threads "racing" will have
151 * wasted their time. The alternative involves creating everything inside the
152 * lock which is far worse.
153 */
154static int dynamic_set_data_ctx(ENGINE *e, dynamic_data_ctx **ctx)
155{
156 dynamic_data_ctx *c = OPENSSL_zalloc(sizeof(*c));
157 int ret = 1;
158
159 if (c == NULL) {
160 ENGINEerr(ENGINE_F_DYNAMIC_SET_DATA_CTX, ERR_R_MALLOC_FAILURE);
161 return 0;
162 }
163 c->dirs = sk_OPENSSL_STRING_new_null();
164 if (c->dirs == NULL) {
165 ENGINEerr(ENGINE_F_DYNAMIC_SET_DATA_CTX, ERR_R_MALLOC_FAILURE);
166 OPENSSL_free(c);
167 return 0;
168 }
169 c->DYNAMIC_F1 = "v_check";
170 c->DYNAMIC_F2 = "bind_engine";
171 c->dir_load = 1;
172 CRYPTO_THREAD_write_lock(global_engine_lock);
173 if ((*ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e,
174 dynamic_ex_data_idx))
175 == NULL) {
176 /* Good, we're the first */
177 ret = ENGINE_set_ex_data(e, dynamic_ex_data_idx, c);
178 if (ret) {
179 *ctx = c;
180 c = NULL;
181 }
182 }
183 CRYPTO_THREAD_unlock(global_engine_lock);
184 /*
185 * If we lost the race to set the context, c is non-NULL and *ctx is the
186 * context of the thread that won.
187 */
188 if (c)
189 sk_OPENSSL_STRING_free(c->dirs);
190 OPENSSL_free(c);
191 return ret;
192}
193
194/*
195 * This function retrieves the context structure from an ENGINE's "ex_data",
196 * or if it doesn't exist yet, sets it up.
197 */
198static dynamic_data_ctx *dynamic_get_data_ctx(ENGINE *e)
199{
200 dynamic_data_ctx *ctx;
201 if (dynamic_ex_data_idx < 0) {
202 /*
203 * Create and register the ENGINE ex_data, and associate our "free"
204 * function with it to ensure any allocated contexts get freed when
205 * an ENGINE goes underground.
206 */
207 int new_idx = ENGINE_get_ex_new_index(0, NULL, NULL, NULL,
208 dynamic_data_ctx_free_func);
209 if (new_idx == -1) {
210 ENGINEerr(ENGINE_F_DYNAMIC_GET_DATA_CTX, ENGINE_R_NO_INDEX);
211 return NULL;
212 }
213 CRYPTO_THREAD_write_lock(global_engine_lock);
214 /* Avoid a race by checking again inside this lock */
215 if (dynamic_ex_data_idx < 0) {
216 /* Good, someone didn't beat us to it */
217 dynamic_ex_data_idx = new_idx;
218 new_idx = -1;
219 }
220 CRYPTO_THREAD_unlock(global_engine_lock);
221 /*
222 * In theory we could "give back" the index here if (new_idx>-1), but
223 * it's not possible and wouldn't gain us much if it were.
224 */
225 }
226 ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e, dynamic_ex_data_idx);
227 /* Check if the context needs to be created */
228 if ((ctx == NULL) && !dynamic_set_data_ctx(e, &ctx))
229 /* "set_data" will set errors if necessary */
230 return NULL;
231 return ctx;
232}
233
234static ENGINE *engine_dynamic(void)
235{
236 ENGINE *ret = ENGINE_new();
237 if (ret == NULL)
238 return NULL;
239 if (!ENGINE_set_id(ret, engine_dynamic_id) ||
240 !ENGINE_set_name(ret, engine_dynamic_name) ||
241 !ENGINE_set_init_function(ret, dynamic_init) ||
242 !ENGINE_set_finish_function(ret, dynamic_finish) ||
243 !ENGINE_set_ctrl_function(ret, dynamic_ctrl) ||
244 !ENGINE_set_flags(ret, ENGINE_FLAGS_BY_ID_COPY) ||
245 !ENGINE_set_cmd_defns(ret, dynamic_cmd_defns)) {
246 ENGINE_free(ret);
247 return NULL;
248 }
249 return ret;
250}
251
252void engine_load_dynamic_int(void)
253{
254 ENGINE *toadd = engine_dynamic();
255 if (!toadd)
256 return;
257 ENGINE_add(toadd);
258 /*
259 * If the "add" worked, it gets a structural reference. So either way, we
260 * release our just-created reference.
261 */
262 ENGINE_free(toadd);
263 /*
264 * If the "add" didn't work, it was probably a conflict because it was
265 * already added (eg. someone calling ENGINE_load_blah then calling
266 * ENGINE_load_builtin_engines() perhaps).
267 */
268 ERR_clear_error();
269}
270
271static int dynamic_init(ENGINE *e)
272{
273 /*
274 * We always return failure - the "dynamic" engine itself can't be used
275 * for anything.
276 */
277 return 0;
278}
279
280static int dynamic_finish(ENGINE *e)
281{
282 /*
283 * This should never be called on account of "dynamic_init" always
284 * failing.
285 */
286 return 0;
287}
288
289static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
290{
291 dynamic_data_ctx *ctx = dynamic_get_data_ctx(e);
292 int initialised;
293
294 if (!ctx) {
295 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_NOT_LOADED);
296 return 0;
297 }
298 initialised = ((ctx->dynamic_dso == NULL) ? 0 : 1);
299 /* All our control commands require the ENGINE to be uninitialised */
300 if (initialised) {
301 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_ALREADY_LOADED);
302 return 0;
303 }
304 switch (cmd) {
305 case DYNAMIC_CMD_SO_PATH:
306 /* a NULL 'p' or a string of zero-length is the same thing */
307 if (p && (strlen((const char *)p) < 1))
308 p = NULL;
309 OPENSSL_free(ctx->DYNAMIC_LIBNAME);
310 if (p)
311 ctx->DYNAMIC_LIBNAME = OPENSSL_strdup(p);
312 else
313 ctx->DYNAMIC_LIBNAME = NULL;
314 return (ctx->DYNAMIC_LIBNAME ? 1 : 0);
315 case DYNAMIC_CMD_NO_VCHECK:
316 ctx->no_vcheck = ((i == 0) ? 0 : 1);
317 return 1;
318 case DYNAMIC_CMD_ID:
319 /* a NULL 'p' or a string of zero-length is the same thing */
320 if (p && (strlen((const char *)p) < 1))
321 p = NULL;
322 OPENSSL_free(ctx->engine_id);
323 if (p)
324 ctx->engine_id = OPENSSL_strdup(p);
325 else
326 ctx->engine_id = NULL;
327 return (ctx->engine_id ? 1 : 0);
328 case DYNAMIC_CMD_LIST_ADD:
329 if ((i < 0) || (i > 2)) {
330 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_INVALID_ARGUMENT);
331 return 0;
332 }
333 ctx->list_add_value = (int)i;
334 return 1;
335 case DYNAMIC_CMD_LOAD:
336 return dynamic_load(e, ctx);
337 case DYNAMIC_CMD_DIR_LOAD:
338 if ((i < 0) || (i > 2)) {
339 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_INVALID_ARGUMENT);
340 return 0;
341 }
342 ctx->dir_load = (int)i;
343 return 1;
344 case DYNAMIC_CMD_DIR_ADD:
345 /* a NULL 'p' or a string of zero-length is the same thing */
346 if (p == NULL || (strlen((const char *)p) < 1)) {
347 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_INVALID_ARGUMENT);
348 return 0;
349 }
350 {
351 char *tmp_str = OPENSSL_strdup(p);
352 if (tmp_str == NULL) {
353 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ERR_R_MALLOC_FAILURE);
354 return 0;
355 }
356 if (!sk_OPENSSL_STRING_push(ctx->dirs, tmp_str)) {
357 OPENSSL_free(tmp_str);
358 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ERR_R_MALLOC_FAILURE);
359 return 0;
360 }
361 }
362 return 1;
363 default:
364 break;
365 }
366 ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_CTRL_COMMAND_NOT_IMPLEMENTED);
367 return 0;
368}
369
370static int int_load(dynamic_data_ctx *ctx)
371{
372 int num, loop;
373 /* Unless told not to, try a direct load */
374 if ((ctx->dir_load != 2) && (DSO_load(ctx->dynamic_dso,
375 ctx->DYNAMIC_LIBNAME, NULL,
376 0)) != NULL)
377 return 1;
378 /* If we're not allowed to use 'dirs' or we have none, fail */
379 if (!ctx->dir_load || (num = sk_OPENSSL_STRING_num(ctx->dirs)) < 1)
380 return 0;
381 for (loop = 0; loop < num; loop++) {
382 const char *s = sk_OPENSSL_STRING_value(ctx->dirs, loop);
383 char *merge = DSO_merge(ctx->dynamic_dso, ctx->DYNAMIC_LIBNAME, s);
384 if (!merge)
385 return 0;
386 if (DSO_load(ctx->dynamic_dso, merge, NULL, 0)) {
387 /* Found what we're looking for */
388 OPENSSL_free(merge);
389 return 1;
390 }
391 OPENSSL_free(merge);
392 }
393 return 0;
394}
395
396static int dynamic_load(ENGINE *e, dynamic_data_ctx *ctx)
397{
398 ENGINE cpy;
399 dynamic_fns fns;
400
401 if (ctx->dynamic_dso == NULL)
402 ctx->dynamic_dso = DSO_new();
403 if (ctx->dynamic_dso == NULL)
404 return 0;
405 if (!ctx->DYNAMIC_LIBNAME) {
406 if (!ctx->engine_id)
407 return 0;
408 DSO_ctrl(ctx->dynamic_dso, DSO_CTRL_SET_FLAGS,
409 DSO_FLAG_NAME_TRANSLATION_EXT_ONLY, NULL);
410 ctx->DYNAMIC_LIBNAME =
411 DSO_convert_filename(ctx->dynamic_dso, ctx->engine_id);
412 }
413 if (!int_load(ctx)) {
414 ENGINEerr(ENGINE_F_DYNAMIC_LOAD, ENGINE_R_DSO_NOT_FOUND);
415 DSO_free(ctx->dynamic_dso);
416 ctx->dynamic_dso = NULL;
417 return 0;
418 }
419 /* We have to find a bind function otherwise it'll always end badly */
420 if (!
421 (ctx->bind_engine =
422 (dynamic_bind_engine) DSO_bind_func(ctx->dynamic_dso,
423 ctx->DYNAMIC_F2))) {
424 ctx->bind_engine = NULL;
425 DSO_free(ctx->dynamic_dso);
426 ctx->dynamic_dso = NULL;
427 ENGINEerr(ENGINE_F_DYNAMIC_LOAD, ENGINE_R_DSO_FAILURE);
428 return 0;
429 }
430 /* Do we perform version checking? */
431 if (!ctx->no_vcheck) {
432 unsigned long vcheck_res = 0;
433 /*
434 * Now we try to find a version checking function and decide how to
435 * cope with failure if/when it fails.
436 */
437 ctx->v_check =
438 (dynamic_v_check_fn) DSO_bind_func(ctx->dynamic_dso,
439 ctx->DYNAMIC_F1);
440 if (ctx->v_check)
441 vcheck_res = ctx->v_check(OSSL_DYNAMIC_VERSION);
442 /*
443 * We fail if the version checker veto'd the load *or* if it is
444 * deferring to us (by returning its version) and we think it is too
445 * old.
446 */
447 if (vcheck_res < OSSL_DYNAMIC_OLDEST) {
448 /* Fail */
449 ctx->bind_engine = NULL;
450 ctx->v_check = NULL;
451 DSO_free(ctx->dynamic_dso);
452 ctx->dynamic_dso = NULL;
453 ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
454 ENGINE_R_VERSION_INCOMPATIBILITY);
455 return 0;
456 }
457 }
458 /*
459 * First binary copy the ENGINE structure so that we can roll back if the
460 * hand-over fails
461 */
462 memcpy(&cpy, e, sizeof(ENGINE));
463 /*
464 * Provide the ERR, "ex_data", memory, and locking callbacks so the
465 * loaded library uses our state rather than its own. FIXME: As noted in
466 * engine.h, much of this would be simplified if each area of code
467 * provided its own "summary" structure of all related callbacks. It
468 * would also increase opaqueness.
469 */
470 fns.static_state = ENGINE_get_static_state();
471 CRYPTO_get_mem_functions(&fns.mem_fns.malloc_fn, &fns.mem_fns.realloc_fn,
472 &fns.mem_fns.free_fn);
473 /*
474 * Now that we've loaded the dynamic engine, make sure no "dynamic"
475 * ENGINE elements will show through.
476 */
477 engine_set_all_null(e);
478
479 /* Try to bind the ENGINE onto our own ENGINE structure */
480 if (!ctx->bind_engine(e, ctx->engine_id, &fns)) {
481 ctx->bind_engine = NULL;
482 ctx->v_check = NULL;
483 DSO_free(ctx->dynamic_dso);
484 ctx->dynamic_dso = NULL;
485 ENGINEerr(ENGINE_F_DYNAMIC_LOAD, ENGINE_R_INIT_FAILED);
486 /* Copy the original ENGINE structure back */
487 memcpy(e, &cpy, sizeof(ENGINE));
488 return 0;
489 }
490 /* Do we try to add this ENGINE to the internal list too? */
491 if (ctx->list_add_value > 0) {
492 if (!ENGINE_add(e)) {
493 /* Do we tolerate this or fail? */
494 if (ctx->list_add_value > 1) {
495 /*
496 * Fail - NB: By this time, it's too late to rollback, and
497 * trying to do so allows the bind_engine() code to have
498 * created leaks. We just have to fail where we are, after
499 * the ENGINE has changed.
500 */
501 ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
502 ENGINE_R_CONFLICTING_ENGINE_ID);
503 return 0;
504 }
505 /* Tolerate */
506 ERR_clear_error();
507 }
508 }
509 return 1;
510}
511