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 */ |
21 | static int dynamic_init(ENGINE *e); |
22 | static int dynamic_finish(ENGINE *e); |
23 | static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p, |
24 | void (*f) (void)); |
25 | /* Predeclare our context type */ |
26 | typedef struct st_dynamic_data_ctx dynamic_data_ctx; |
27 | /* The implementation for the important control command */ |
28 | static 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 */ |
39 | static const char *engine_dynamic_id = "dynamic" ; |
40 | static const char *engine_dynamic_name = "Dynamic engine loading support" ; |
41 | static 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 | */ |
78 | struct 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 | */ |
118 | static int dynamic_ex_data_idx = -1; |
119 | |
120 | static 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 | */ |
134 | static 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 | */ |
154 | static 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 | */ |
198 | static 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 | |
234 | static 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 | |
252 | void 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 | |
271 | static 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 | |
280 | static 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 | |
289 | static 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 | |
370 | static 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 | |
396 | static 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 | |