/*
* Copyright 2001-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "eng_local.h"
#include "internal/dso.h"
#include <openssl/crypto.h>
/*
* Shared libraries implementing ENGINEs for use by the "dynamic" ENGINE
* loader should implement the hook-up functions with the following
* prototypes.
*/
/* Our ENGINE handlers */
static int dynamic_init(ENGINE *e);
static int dynamic_finish(ENGINE *e);
static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p,
void (*f) (void));
/* Predeclare our context type */
typedef struct st_dynamic_data_ctx dynamic_data_ctx;
/* The implementation for the important control command */
static int dynamic_load(ENGINE *e, dynamic_data_ctx *ctx);
#define DYNAMIC_CMD_SO_PATH ENGINE_CMD_BASE
#define DYNAMIC_CMD_NO_VCHECK (ENGINE_CMD_BASE + 1)
#define DYNAMIC_CMD_ID (ENGINE_CMD_BASE + 2)
#define DYNAMIC_CMD_LIST_ADD (ENGINE_CMD_BASE + 3)
#define DYNAMIC_CMD_DIR_LOAD (ENGINE_CMD_BASE + 4)
#define DYNAMIC_CMD_DIR_ADD (ENGINE_CMD_BASE + 5)
#define DYNAMIC_CMD_LOAD (ENGINE_CMD_BASE + 6)
/* The constants used when creating the ENGINE */
static const char *engine_dynamic_id = "dynamic";
static const char *engine_dynamic_name = "Dynamic engine loading support";
static const ENGINE_CMD_DEFN dynamic_cmd_defns[] = {
{DYNAMIC_CMD_SO_PATH,
"SO_PATH",
"Specifies the path to the new ENGINE shared library",
ENGINE_CMD_FLAG_STRING},
{DYNAMIC_CMD_NO_VCHECK,
"NO_VCHECK",
"Specifies to continue even if version checking fails (boolean)",
ENGINE_CMD_FLAG_NUMERIC},
{DYNAMIC_CMD_ID,
"ID",
"Specifies an ENGINE id name for loading",
ENGINE_CMD_FLAG_STRING},
{DYNAMIC_CMD_LIST_ADD,
"LIST_ADD",
"Whether to add a loaded ENGINE to the internal list (0=no,1=yes,2=mandatory)",
ENGINE_CMD_FLAG_NUMERIC},
{DYNAMIC_CMD_DIR_LOAD,
"DIR_LOAD",
"Specifies whether to load from 'DIR_ADD' directories (0=no,1=yes,2=mandatory)",
ENGINE_CMD_FLAG_NUMERIC},
{DYNAMIC_CMD_DIR_ADD,
"DIR_ADD",
"Adds a directory from which ENGINEs can be loaded",
ENGINE_CMD_FLAG_STRING},
{DYNAMIC_CMD_LOAD,
"LOAD",
"Load up the ENGINE specified by other settings",
ENGINE_CMD_FLAG_NO_INPUT},
{0, NULL, NULL, 0}
};
/*
* Loading code stores state inside the ENGINE structure via the "ex_data"
* element. We load all our state into a single structure and use that as a
* single context in the "ex_data" stack.
*/
struct st_dynamic_data_ctx {
/* The DSO object we load that supplies the ENGINE code */
DSO *dynamic_dso;
/*
* The function pointer to the version checking shared library function
*/
dynamic_v_check_fn v_check;
/*
* The function pointer to the engine-binding shared library function
*/
dynamic_bind_engine bind_engine;
/* The default name/path for loading the shared library */
char *DYNAMIC_LIBNAME;
/* Whether to continue loading on a version check failure */
int no_vcheck;
/* If non-NULL, stipulates the 'id' of the ENGINE to be loaded */
char *engine_id;
/*
* If non-zero, a successfully loaded ENGINE should be added to the
* internal ENGINE list. If 2, the add must succeed or the entire load
* should fail.
*/
int list_add_value;
/* The symbol name for the version checking function */
const char *DYNAMIC_F1;
/* The symbol name for the "initialise ENGINE structure" function */
const char *DYNAMIC_F2;
/*
* Whether to never use 'dirs', use 'dirs' as a fallback, or only use
* 'dirs' for loading. Default is to use 'dirs' as a fallback.
*/
int dir_load;
/* A stack of directories from which ENGINEs could be loaded */
STACK_OF(OPENSSL_STRING) *dirs;
};
/*
* This is the "ex_data" index we obtain and reserve for use with our context
* structure.
*/
static int dynamic_ex_data_idx = -1;
static void int_free_str(char *s)
{
OPENSSL_free(s);
}
/*
* Because our ex_data element may or may not get allocated depending on
* whether a "first-use" occurs before the ENGINE is freed, we have a memory
* leak problem to solve. We can't declare a "new" handler for the ex_data as
* we don't want a dynamic_data_ctx in *all* ENGINE structures of all types
* (this is a bug in the design of CRYPTO_EX_DATA). As such, we just declare
* a "free" handler and that will get called if an ENGINE is being destroyed
* and there was an ex_data element corresponding to our context type.
*/
static void dynamic_data_ctx_free_func(void *parent, void *ptr,
CRYPTO_EX_DATA *ad, int idx, long argl,
void *argp)
{
if (ptr) {
dynamic_data_ctx *ctx = (dynamic_data_ctx *)ptr;
DSO_free(ctx->dynamic_dso);
OPENSSL_free(ctx->DYNAMIC_LIBNAME);
OPENSSL_free(ctx->engine_id);
sk_OPENSSL_STRING_pop_free(ctx->dirs, int_free_str);
OPENSSL_free(ctx);
}
}
/*
* Construct the per-ENGINE context. We create it blindly and then use a lock
* to check for a race - if so, all but one of the threads "racing" will have
* wasted their time. The alternative involves creating everything inside the
* lock which is far worse.
*/
static int dynamic_set_data_ctx(ENGINE *e, dynamic_data_ctx **ctx)
{
dynamic_data_ctx *c = OPENSSL_zalloc(sizeof(*c));
int ret = 1;
if (c == NULL) {
ENGINEerr(ENGINE_F_DYNAMIC_SET_DATA_CTX, ERR_R_MALLOC_FAILURE);
return 0;
}
c->dirs = sk_OPENSSL_STRING_new_null();
if (c->dirs == NULL) {
ENGINEerr(ENGINE_F_DYNAMIC_SET_DATA_CTX, ERR_R_MALLOC_FAILURE);
OPENSSL_free(c);
return 0;
}
c->DYNAMIC_F1 = "v_check";
c->DYNAMIC_F2 = "bind_engine";
c->dir_load = 1;
CRYPTO_THREAD_write_lock(global_engine_lock);
if ((*ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e,
dynamic_ex_data_idx))
== NULL) {
/* Good, we're the first */
ret = ENGINE_set_ex_data(e, dynamic_ex_data_idx, c);
if (ret) {
*ctx = c;
c = NULL;
}
}
CRYPTO_THREAD_unlock(global_engine_lock);
/*
* If we lost the race to set the context, c is non-NULL and *ctx is the
* context of the thread that won.
*/
if (c)
sk_OPENSSL_STRING_free(c->dirs);
OPENSSL_free(c);
return ret;
}
/*
* This function retrieves the context structure from an ENGINE's "ex_data",
* or if it doesn't exist yet, sets it up.
*/
static dynamic_data_ctx *dynamic_get_data_ctx(ENGINE *e)
{
dynamic_data_ctx *ctx;
if (dynamic_ex_data_idx < 0) {
/*
* Create and register the ENGINE ex_data, and associate our "free"
* function with it to ensure any allocated contexts get freed when
* an ENGINE goes underground.
*/
int new_idx = ENGINE_get_ex_new_index(0, NULL, NULL, NULL,
dynamic_data_ctx_free_func);
if (new_idx == -1) {
ENGINEerr(ENGINE_F_DYNAMIC_GET_DATA_CTX, ENGINE_R_NO_INDEX);
return NULL;
}
CRYPTO_THREAD_write_lock(global_engine_lock);
/* Avoid a race by checking again inside this lock */
if (dynamic_ex_data_idx < 0) {
/* Good, someone didn't beat us to it */
dynamic_ex_data_idx = new_idx;
new_idx = -1;
}
CRYPTO_THREAD_unlock(global_engine_lock);
/*
* In theory we could "give back" the index here if (new_idx>-1), but
* it's not possible and wouldn't gain us much if it were.
*/
}
ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e, dynamic_ex_data_idx);
/* Check if the context needs to be created */
if ((ctx == NULL) && !dynamic_set_data_ctx(e, &ctx))
/* "set_data" will set errors if necessary */
return NULL;
return ctx;
}
static ENGINE *engine_dynamic(void)
{
ENGINE *ret = ENGINE_new();
if (ret == NULL)
return NULL;
if (!ENGINE_set_id(ret, engine_dynamic_id) ||
!ENGINE_set_name(ret, engine_dynamic_name) ||
!ENGINE_set_init_function(ret, dynamic_init) ||
!ENGINE_set_finish_function(ret, dynamic_finish) ||
!ENGINE_set_ctrl_function(ret, dynamic_ctrl) ||
!ENGINE_set_flags(ret, ENGINE_FLAGS_BY_ID_COPY) ||
!ENGINE_set_cmd_defns(ret, dynamic_cmd_defns)) {
ENGINE_free(ret);
return NULL;
}
return ret;
}
void engine_load_dynamic_int(void)
{
ENGINE *toadd = engine_dynamic();
if (!toadd)
return;
ENGINE_add(toadd);
/*
* If the "add" worked, it gets a structural reference. So either way, we
* release our just-created reference.
*/
ENGINE_free(toadd);
/*
* If the "add" didn't work, it was probably a conflict because it was
* already added (eg. someone calling ENGINE_load_blah then calling
* ENGINE_load_builtin_engines() perhaps).
*/
ERR_clear_error();
}
static int dynamic_init(ENGINE *e)
{
/*
* We always return failure - the "dynamic" engine itself can't be used
* for anything.
*/
return 0;
}
static int dynamic_finish(ENGINE *e)
{
/*
* This should never be called on account of "dynamic_init" always
* failing.
*/
return 0;
}
static int dynamic_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
{
dynamic_data_ctx *ctx = dynamic_get_data_ctx(e);
int initialised;
if (!ctx) {
ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_NOT_LOADED);
return 0;
}
initialised = ((ctx->dynamic_dso == NULL) ? 0 : 1);
/* All our control commands require the ENGINE to be uninitialised */
if (initialised) {
ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_ALREADY_LOADED);
return 0;
}
switch (cmd) {
case DYNAMIC_CMD_SO_PATH:
/* a NULL 'p' or a string of zero-length is the same thing */
if (p && (strlen((const char *)p) < 1))
p = NULL;
OPENSSL_free(ctx->DYNAMIC_LIBNAME);
if (p)
ctx->DYNAMIC_LIBNAME = OPENSSL_strdup(p);
else
ctx->DYNAMIC_LIBNAME = NULL;
return (ctx->DYNAMIC_LIBNAME ? 1 : 0);
case DYNAMIC_CMD_NO_VCHECK:
ctx->no_vcheck = ((i == 0) ? 0 : 1);
return 1;
case DYNAMIC_CMD_ID:
/* a NULL 'p' or a string of zero-length is the same thing */
if (p && (strlen((const char *)p) < 1))
p = NULL;
OPENSSL_free(ctx->engine_id);
if (p)
ctx->engine_id = OPENSSL_strdup(p);
else
ctx->engine_id = NULL;
return (ctx->engine_id ? 1 : 0);
case DYNAMIC_CMD_LIST_ADD:
if ((i < 0) || (i > 2)) {
ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_INVALID_ARGUMENT);
return 0;
}
ctx->list_add_value = (int)i;
return 1;
case DYNAMIC_CMD_LOAD:
return dynamic_load(e, ctx);
case DYNAMIC_CMD_DIR_LOAD:
if ((i < 0) || (i > 2)) {
ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_INVALID_ARGUMENT);
return 0;
}
ctx->dir_load = (int)i;
return 1;
case DYNAMIC_CMD_DIR_ADD:
/* a NULL 'p' or a string of zero-length is the same thing */
if (!p || (strlen((const char *)p) < 1)) {
ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_INVALID_ARGUMENT);
return 0;
}
{
char *tmp_str = OPENSSL_strdup(p);
if (tmp_str == NULL) {
ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ERR_R_MALLOC_FAILURE);
return 0;
}
if (!sk_OPENSSL_STRING_push(ctx->dirs, tmp_str)) {
OPENSSL_free(tmp_str);
ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ERR_R_MALLOC_FAILURE);
return 0;
}
}
return 1;
default:
break;
}
ENGINEerr(ENGINE_F_DYNAMIC_CTRL, ENGINE_R_CTRL_COMMAND_NOT_IMPLEMENTED);
return 0;
}
static int int_load(dynamic_data_ctx *ctx)
{
int num, loop;
/* Unless told not to, try a direct load */
if ((ctx->dir_load != 2) && (DSO_load(ctx->dynamic_dso,
ctx->DYNAMIC_LIBNAME, NULL,
0)) != NULL)
return 1;
/* If we're not allowed to use 'dirs' or we have none, fail */
if (!ctx->dir_load || (num = sk_OPENSSL_STRING_num(ctx->dirs)) < 1)
return 0;
for (loop = 0; loop < num; loop++) {
const char *s = sk_OPENSSL_STRING_value(ctx->dirs, loop);
char *merge = DSO_merge(ctx->dynamic_dso, ctx->DYNAMIC_LIBNAME, s);
if (!merge)
return 0;
if (DSO_load(ctx->dynamic_dso, merge, NULL, 0)) {
/* Found what we're looking for */
OPENSSL_free(merge);
return 1;
}
OPENSSL_free(merge);
}
return 0;
}
static int dynamic_load(ENGINE *e, dynamic_data_ctx *ctx)
{
ENGINE cpy;
dynamic_fns fns;
if (ctx->dynamic_dso == NULL)
ctx->dynamic_dso = DSO_new();
if (ctx->dynamic_dso == NULL)
return 0;
if (!ctx->DYNAMIC_LIBNAME) {
if (!ctx->engine_id)
return 0;
DSO_ctrl(ctx->dynamic_dso, DSO_CTRL_SET_FLAGS,
DSO_FLAG_NAME_TRANSLATION_EXT_ONLY, NULL);
ctx->DYNAMIC_LIBNAME =
DSO_convert_filename(ctx->dynamic_dso, ctx->engine_id);
}
if (!int_load(ctx)) {
ENGINEerr(ENGINE_F_DYNAMIC_LOAD, ENGINE_R_DSO_NOT_FOUND);
DSO_free(ctx->dynamic_dso);
ctx->dynamic_dso = NULL;
return 0;
}
/* We have to find a bind function otherwise it'll always end badly */
if (!
(ctx->bind_engine =
(dynamic_bind_engine) DSO_bind_func(ctx->dynamic_dso,
ctx->DYNAMIC_F2))) {
ctx->bind_engine = NULL;
DSO_free(ctx->dynamic_dso);
ctx->dynamic_dso = NULL;
ENGINEerr(ENGINE_F_DYNAMIC_LOAD, ENGINE_R_DSO_FAILURE);
return 0;
}
/* Do we perform version checking? */
if (!ctx->no_vcheck) {
unsigned long vcheck_res = 0;
/*
* Now we try to find a version checking function and decide how to
* cope with failure if/when it fails.
*/
ctx->v_check =
(dynamic_v_check_fn) DSO_bind_func(ctx->dynamic_dso,
ctx->DYNAMIC_F1);
if (ctx->v_check)
vcheck_res = ctx->v_check(OSSL_DYNAMIC_VERSION);
/*
* We fail if the version checker veto'd the load *or* if it is
* deferring to us (by returning its version) and we think it is too
* old.
*/
if (vcheck_res < OSSL_DYNAMIC_OLDEST) {
/* Fail */
ctx->bind_engine = NULL;
ctx->v_check = NULL;
DSO_free(ctx->dynamic_dso);
ctx->dynamic_dso = NULL;
ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
ENGINE_R_VERSION_INCOMPATIBILITY);
return 0;
}
}
/*
* First binary copy the ENGINE structure so that we can roll back if the
* hand-over fails
*/
memcpy(&cpy, e, sizeof(ENGINE));
/*
* Provide the ERR, "ex_data", memory, and locking callbacks so the
* loaded library uses our state rather than its own. FIXME: As noted in
* engine.h, much of this would be simplified if each area of code
* provided its own "summary" structure of all related callbacks. It
* would also increase opaqueness.
*/
fns.static_state = ENGINE_get_static_state();
CRYPTO_get_mem_functions(&fns.mem_fns.malloc_fn, &fns.mem_fns.realloc_fn,
&fns.mem_fns.free_fn);
/*
* Now that we've loaded the dynamic engine, make sure no "dynamic"
* ENGINE elements will show through.
*/
engine_set_all_null(e);
/* Try to bind the ENGINE onto our own ENGINE structure */
if (!ctx->bind_engine(e, ctx->engine_id, &fns)) {
ctx->bind_engine = NULL;
ctx->v_check = NULL;
DSO_free(ctx->dynamic_dso);
ctx->dynamic_dso = NULL;
ENGINEerr(ENGINE_F_DYNAMIC_LOAD, ENGINE_R_INIT_FAILED);
/* Copy the original ENGINE structure back */
memcpy(e, &cpy, sizeof(ENGINE));
return 0;
}
/* Do we try to add this ENGINE to the internal list too? */
if (ctx->list_add_value > 0) {
if (!ENGINE_add(e)) {
/* Do we tolerate this or fail? */
if (ctx->list_add_value > 1) {
/*
* Fail - NB: By this time, it's too late to rollback, and
* trying to do so allows the bind_engine() code to have
* created leaks. We just have to fail where we are, after
* the ENGINE has changed.
*/
ENGINEerr(ENGINE_F_DYNAMIC_LOAD,
ENGINE_R_CONFLICTING_ENGINE_ID);
return 0;
}
/* Tolerate */
ERR_clear_error();
}
}
return 1;
}