text: /*
   * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the Apache License 2.0 (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 <openssl/core.h>
  #include <openssl/core_numbers.h>
  #include <openssl/params.h>
  #include <openssl/opensslv.h>
  #include "internal/cryptlib.h"
  #include "internal/nelem.h"
  #include "internal/thread_once.h"
  #include "internal/provider.h"
  #include "internal/refcount.h"
  #include "provider_local.h"
  
  static OSSL_PROVIDER *provider_new(const char *name,
                                     OSSL_provider_init_fn *init_function);
  
  /*-
   * Provider Object structure
   * =========================
   */
  
  typedef struct {
      char *name;
      char *value;
  } INFOPAIR;
  DEFINE_STACK_OF(INFOPAIR)
  
  struct provider_store_st;        /* Forward declaration */
  
  struct ossl_provider_st {
      /* Flag bits */
      unsigned int flag_initialized:1;
      unsigned int flag_fallback:1;
  
      /* OpenSSL library side data */
      CRYPTO_REF_COUNT refcnt;
      CRYPTO_RWLOCK *refcnt_lock;  /* For the ref counter */
      char *name;
      char *path;
      DSO *module;
      OSSL_provider_init_fn *init_function;
      STACK_OF(INFOPAIR) *parameters;
      struct provider_store_st *store; /* The store this instance belongs to */
  
      /* Provider side functions */
      OSSL_provider_teardown_fn *teardown;
      OSSL_provider_get_param_types_fn *get_param_types;
      OSSL_provider_get_params_fn *get_params;
      OSSL_provider_query_operation_fn *query_operation;
  
      /* Provider side data */
      void *provctx;
  };
  DEFINE_STACK_OF(OSSL_PROVIDER)
  
  static int ossl_provider_cmp(const OSSL_PROVIDER * const *a,
                               const OSSL_PROVIDER * const *b)
  {
      return strcmp((*a)->name, (*b)->name);
  }
  
  /*-
   * Provider Object store
   * =====================
   *
   * The Provider Object store is a library context object, and therefore needs
   * an index.
   */
  
  struct provider_store_st {
      STACK_OF(OSSL_PROVIDER) *providers;
      CRYPTO_RWLOCK *lock;
      unsigned int use_fallbacks:1;
  };
  
  static void provider_store_free(void *vstore)
  {
      struct provider_store_st *store = vstore;
  
      if (store == NULL)
          return;
      sk_OSSL_PROVIDER_pop_free(store->providers, ossl_provider_free);
      CRYPTO_THREAD_lock_free(store->lock);
      OPENSSL_free(store);
  }
  
  static void *provider_store_new(OPENSSL_CTX *ctx)
  {
      struct provider_store_st *store = OPENSSL_zalloc(sizeof(*store));
      const struct predefined_providers_st *p = NULL;
  
      if (store == NULL
          || (store->providers = sk_OSSL_PROVIDER_new(ossl_provider_cmp)) == NULL
          || (store->lock = CRYPTO_THREAD_lock_new()) == NULL) {
          provider_store_free(store);
          return NULL;
      }
      store->use_fallbacks = 1;
  
      for (p = predefined_providers; p->name != NULL; p++) {
          OSSL_PROVIDER *prov = NULL;
  
          /*
           * We use the internal constructor directly here,
           * otherwise we get a call loop
           */
          prov = provider_new(p->name, p->init);
  
          if (prov == NULL
              || sk_OSSL_PROVIDER_push(store->providers, prov) == 0) {
              ossl_provider_free(prov);
              provider_store_free(store);
              CRYPTOerr(CRYPTO_F_PROVIDER_STORE_NEW, ERR_R_INTERNAL_ERROR);
              return NULL;
          }
          prov->store = store;
          if(p->is_fallback)
              ossl_provider_set_fallback(prov);
      }
  
      return store;
  }
  
  static const OPENSSL_CTX_METHOD provider_store_method = {
      provider_store_new,
      provider_store_free,
  };
  
  static struct provider_store_st *get_provider_store(OPENSSL_CTX *libctx)
  {
      struct provider_store_st *store = NULL;
  
      store = openssl_ctx_get_data(libctx, OPENSSL_CTX_PROVIDER_STORE_INDEX,
                                   &provider_store_method);
      if (store == NULL)
          CRYPTOerr(CRYPTO_F_GET_PROVIDER_STORE, ERR_R_INTERNAL_ERROR);
      return store;
  }
  
  OSSL_PROVIDER *ossl_provider_find(OPENSSL_CTX *libctx, const char *name)
  {
      struct provider_store_st *store = NULL;
      OSSL_PROVIDER *prov = NULL;
  
      if ((store = get_provider_store(libctx)) != NULL) {
          OSSL_PROVIDER tmpl = { 0, };
          int i;
  
          tmpl.name = (char *)name;
          CRYPTO_THREAD_write_lock(store->lock);
          if ((i = sk_OSSL_PROVIDER_find(store->providers, &tmpl)) == -1
              || (prov = sk_OSSL_PROVIDER_value(store->providers, i)) == NULL
              || !ossl_provider_upref(prov))
              prov = NULL;
          CRYPTO_THREAD_unlock(store->lock);
      }
  
      return prov;
  }
  
  /*-
   * Provider Object methods
   * =======================
   */
  
  static OSSL_PROVIDER *provider_new(const char *name,
                                     OSSL_provider_init_fn *init_function)
  {
      OSSL_PROVIDER *prov = NULL;
  
      if ((prov = OPENSSL_zalloc(sizeof(*prov))) == NULL
  #ifndef HAVE_ATOMICS
          || (prov->refcnt_lock = CRYPTO_THREAD_lock_new()) == NULL
  #endif
          || !ossl_provider_upref(prov) /* +1 One reference to be returned */
          || (prov->name = OPENSSL_strdup(name)) == NULL) {
          ossl_provider_free(prov);
          CRYPTOerr(CRYPTO_F_PROVIDER_NEW, ERR_R_MALLOC_FAILURE);
          return NULL;
      }
  
      prov->init_function = init_function;
      return prov;
  }
  
  int ossl_provider_upref(OSSL_PROVIDER *prov)
  {
      int ref = 0;
  
      CRYPTO_UP_REF(&prov->refcnt, &ref, prov->refcnt_lock);
      return ref;
  }
  
  OSSL_PROVIDER *ossl_provider_new(OPENSSL_CTX *libctx, const char *name,
                                   OSSL_provider_init_fn *init_function)
  {
      struct provider_store_st *store = NULL;
      OSSL_PROVIDER *prov = NULL;
  
      if ((store = get_provider_store(libctx)) == NULL)
          return NULL;
  
      if ((prov = ossl_provider_find(libctx, name)) != NULL) { /* refcount +1 */
          ossl_provider_free(prov); /* refcount -1 */
          CRYPTOerr(CRYPTO_F_OSSL_PROVIDER_NEW,
                    CRYPTO_R_PROVIDER_ALREADY_EXISTS);
          ERR_add_error_data(2, "name=", name);
          return NULL;
      }
  
      /* provider_new() generates an error, so no need here */
      if ((prov = provider_new(name, init_function)) == NULL)
          return NULL;
  
      CRYPTO_THREAD_write_lock(store->lock);
      if (!ossl_provider_upref(prov)) { /* +1 One reference for the store */
          ossl_provider_free(prov); /* -1 Reference that was to be returned */
          prov = NULL;
      } else if (sk_OSSL_PROVIDER_push(store->providers, prov) == 0) {
          ossl_provider_free(prov); /* -1 Store reference */
          ossl_provider_free(prov); /* -1 Reference that was to be returned */
          prov = NULL;
      } else {
          prov->store = store;
      }
      CRYPTO_THREAD_unlock(store->lock);
  
      if (prov == NULL)
          CRYPTOerr(CRYPTO_F_OSSL_PROVIDER_NEW, ERR_R_MALLOC_FAILURE);
  
      /*
       * At this point, the provider is only partially "loaded".  To be
       * fully "loaded", ossl_provider_activate() must also be called.
       */
  
      return prov;
  }
  
  static void free_infopair(INFOPAIR *pair)
  {
      OPENSSL_free(pair->name);
      OPENSSL_free(pair->value);
      OPENSSL_free(pair);
  }
  
  void ossl_provider_free(OSSL_PROVIDER *prov)
  {
      if (prov != NULL) {
          int ref = 0;
  
          CRYPTO_DOWN_REF(&prov->refcnt, &ref, prov->refcnt_lock);
  
          /*
           * When the refcount drops below two, the store is the only
           * possible reference, or it has already been taken away from
           * the store (this may happen if a provider was activated
           * because it's a fallback, but isn't currently used)
           * When that happens, the provider is inactivated.
           */
          if (ref < 2 && prov->flag_initialized) {
              if (prov->teardown != NULL)
                  prov->teardown(prov->provctx);
              prov->flag_initialized = 0;
          }
  
          /*
           * When the refcount drops to zero, it has been taken out of
           * the store.  All we have to do here is clean it out.
           */
          if (ref == 0) {
  #ifndef FIPS_MODE
              DSO_free(prov->module);
  #endif
              OPENSSL_free(prov->name);
              OPENSSL_free(prov->path);
              sk_INFOPAIR_pop_free(prov->parameters, free_infopair);
  #ifndef HAVE_ATOMICS
              CRYPTO_THREAD_lock_free(prov->refcnt_lock);
  #endif
              OPENSSL_free(prov);
          }
      }
  }
  
  /* Setters */
  int ossl_provider_set_module_path(OSSL_PROVIDER *prov, const char *module_path)
  {
      OPENSSL_free(prov->path);
      if (module_path == NULL)
          return 1;
      if ((prov->path = OPENSSL_strdup(module_path)) != NULL)
          return 1;
      CRYPTOerr(CRYPTO_F_OSSL_PROVIDER_SET_MODULE_PATH, ERR_R_MALLOC_FAILURE);
      return 0;
  }
  
  int ossl_provider_add_parameter(OSSL_PROVIDER *prov,
                                  const char *name, const char *value)
  {
      INFOPAIR *pair = NULL;
  
      if ((pair = OPENSSL_zalloc(sizeof(*pair))) != NULL
          && (prov->parameters != NULL
              || (prov->parameters = sk_INFOPAIR_new_null()) != NULL)
          && (pair->name = OPENSSL_strdup(name)) != NULL
          && (pair->value = OPENSSL_strdup(value)) != NULL
          && sk_INFOPAIR_push(prov->parameters, pair) > 0)
          return 1;
  
      if (pair != NULL) {
          OPENSSL_free(pair->name);
          OPENSSL_free(pair->value);
          OPENSSL_free(pair);
      }
      CRYPTOerr(CRYPTO_F_OSSL_PROVIDER_ADD_PARAMETER, ERR_R_MALLOC_FAILURE);
      return 0;
  }
  
  /*
   * Provider activation.
   *
   * What "activation" means depends on the provider form; for built in
   * providers (in the library or the application alike), the provider
   * can already be considered to be loaded, all that's needed is to
   * initialize it.  However, for dynamically loadable provider modules,
   * we must first load that module.
   *
   * Built in modules are distinguished from dynamically loaded modules
   * with an already assigned init function.
   */
  static const OSSL_DISPATCH *core_dispatch; /* Define further down */
  
  /*
   * Internal version that doesn't affect the store flags, and thereby avoid
   * locking.  Direct callers must remember to set the store flags when
   * appropriate. The libctx parameter is only necessary when FIPS_MODE is set
   * (i.e. we are being called from inside the FIPS module) - it is ignored for
   * other uses.
   */
  static int provider_activate(OSSL_PROVIDER *prov, OPENSSL_CTX *libctx)
  {
      const OSSL_DISPATCH *provider_dispatch = NULL;
  
      if (prov->flag_initialized)
          return 1;
  
      /*
       * If the init function isn't set, it indicates that this provider is
       * a loadable module.
       */
      if (prov->init_function == NULL) {
  #ifdef FIPS_MODE
          return 0;
  #else
          if (prov->module == NULL) {
              char *allocated_path = NULL;
              const char *module_path = NULL;
              char *merged_path = NULL;
              const char *load_dir = ossl_safe_getenv("OPENSSL_MODULES");
  
              if ((prov->module = DSO_new()) == NULL) {
                  /* DSO_new() generates an error already */
                  return 0;
              }
  
              if (load_dir == NULL)
                  load_dir = MODULESDIR;
  
              DSO_ctrl(prov->module, DSO_CTRL_SET_FLAGS,
                       DSO_FLAG_NAME_TRANSLATION_EXT_ONLY, NULL);
  
              module_path = prov->path;
              if (module_path == NULL)
                  module_path = allocated_path =
                      DSO_convert_filename(prov->module, prov->name);
              if (module_path != NULL)
                  merged_path = DSO_merge(prov->module, module_path, load_dir);
  
              if (merged_path == NULL
                  || (DSO_load(prov->module, merged_path, NULL, 0)) == NULL) {
                  DSO_free(prov->module);
                  prov->module = NULL;
              }
  
              OPENSSL_free(merged_path);
              OPENSSL_free(allocated_path);
          }
  
          if (prov->module != NULL)
              prov->init_function = (OSSL_provider_init_fn *)
                  DSO_bind_func(prov->module, "OSSL_provider_init");
  #endif
      }
  
      /*
       * We call the initialise function for the provider.
       *
       * If FIPS_MODE is defined then we are inside the FIPS module and are about
       * to recursively initialise ourselves. We need to do this so that we can
       * get all the provider callback functions set up in order for us to be able
       * to make EVP calls from within the FIPS module itself. Only algorithms
       * from the FIPS module itself are available via the FIPS module EVP
       * interface, i.e. we only ever have one provider available inside the FIPS
       * module - the FIPS provider itself.
       *
       * For modules in general we cannot know what value will be used for the
       * provctx - it is a "black box". But for the FIPS module we know that the
       * provctx is really a library context. We default the provctx value to the
       * same library context as was used for the EVP call that caused this call
       * to "provider_activate".
       */
  #ifdef FIPS_MODE
      prov->provctx = libctx;
  #endif
      if (prov->init_function == NULL
          || !prov->init_function(prov, core_dispatch, &provider_dispatch,
                                  &prov->provctx)) {
          CRYPTOerr(CRYPTO_F_PROVIDER_ACTIVATE, ERR_R_INIT_FAIL);
          ERR_add_error_data(2, "name=", prov->name);
  #ifndef FIPS_MODE
          DSO_free(prov->module);
          prov->module = NULL;
  #endif
          return 0;
      }
  
      for (; provider_dispatch->function_id != 0; provider_dispatch++) {
          switch (provider_dispatch->function_id) {
          case OSSL_FUNC_PROVIDER_TEARDOWN:
              prov->teardown =
                  OSSL_get_provider_teardown(provider_dispatch);
              break;
          case OSSL_FUNC_PROVIDER_GET_PARAM_TYPES:
              prov->get_param_types =
                  OSSL_get_provider_get_param_types(provider_dispatch);
              break;
          case OSSL_FUNC_PROVIDER_GET_PARAMS:
              prov->get_params =
                  OSSL_get_provider_get_params(provider_dispatch);
              break;
          case OSSL_FUNC_PROVIDER_QUERY_OPERATION:
              prov->query_operation =
                  OSSL_get_provider_query_operation(provider_dispatch);
              break;
          }
      }
  
      /* With this flag set, this provider has become fully "loaded". */
      prov->flag_initialized = 1;
  
      return 1;
  }
  
  int ossl_provider_activate(OSSL_PROVIDER *prov)
  {
      if (provider_activate(prov, NULL)) {
          CRYPTO_THREAD_write_lock(prov->store->lock);
          prov->store->use_fallbacks = 0;
          CRYPTO_THREAD_unlock(prov->store->lock);
          return 1;
      }
  
      return 0;
  }
  
  void *ossl_provider_ctx(const OSSL_PROVIDER *prov)
  {
      return prov->provctx;
  }
  
  
  static int provider_forall_loaded(struct provider_store_st *store,
                                    int *found_activated,
                                    int (*cb)(OSSL_PROVIDER *provider,
                                              void *cbdata),
                                    void *cbdata)
  {
      int i;
      int ret = 1;
      int num_provs = sk_OSSL_PROVIDER_num(store->providers);
  
      if (found_activated != NULL)
          *found_activated = 0;
      for (i = 0; i < num_provs; i++) {
          OSSL_PROVIDER *prov =
              sk_OSSL_PROVIDER_value(store->providers, i);
  
          if (prov->flag_initialized) {
              if (found_activated != NULL)
                  *found_activated = 1;
              if (!(ret = cb(prov, cbdata)))
                  break;
          }
      }
  
      return ret;
  }
  
  int ossl_provider_forall_loaded(OPENSSL_CTX *ctx,
                                  int (*cb)(OSSL_PROVIDER *provider,
                                            void *cbdata),
                                  void *cbdata)
  {
      int ret = 1;
      int i;
      struct provider_store_st *store = get_provider_store(ctx);
  
      if (store != NULL) {
          int found_activated = 0;
  
          CRYPTO_THREAD_read_lock(store->lock);
          ret = provider_forall_loaded(store, &found_activated, cb, cbdata);
  
          /*
           * If there's nothing activated ever in this store, try to activate
           * all fallbacks.
           */
          if (!found_activated && store->use_fallbacks) {
              int num_provs = sk_OSSL_PROVIDER_num(store->providers);
              int activated_fallback_count = 0;
  
              for (i = 0; i < num_provs; i++) {
                  OSSL_PROVIDER *prov =
                      sk_OSSL_PROVIDER_value(store->providers, i);
  
                  /*
                   * Note that we don't care if the activation succeeds or
                   * not.  If it doesn't succeed, then the next loop will
                   * fail anyway.
                   */
                  if (prov->flag_fallback) {
                      activated_fallback_count++;
                      provider_activate(prov, ctx);
                  }
              }
  
              if (activated_fallback_count > 0) {
                  /*
                   * We assume that all fallbacks have been added to the store
                   * before any fallback is activated.
                   * TODO: We may have to reconsider this, IF we find ourselves
                   * adding fallbacks after any previous fallback has been
                   * activated.
                   */
                  store->use_fallbacks = 0;
  
                  /*
                   * Now that we've activated available fallbacks, try a
                   * second sweep
                   */
                  ret = provider_forall_loaded(store, NULL, cb, cbdata);
              }
          }
          CRYPTO_THREAD_unlock(store->lock);
      }
  
      return ret;
  }
  
  /* Setters of Provider Object data */
  int ossl_provider_set_fallback(OSSL_PROVIDER *prov)
  {
      if (prov == NULL)
          return 0;
  
      prov->flag_fallback = 1;
      return 1;
  }
  
  /* Getters of Provider Object data */
  const char *ossl_provider_name(OSSL_PROVIDER *prov)
  {
      return prov->name;
  }
  
  const DSO *ossl_provider_dso(OSSL_PROVIDER *prov)
  {
      return prov->module;
  }
  
  const char *ossl_provider_module_name(OSSL_PROVIDER *prov)
  {
  #ifdef FIPS_MODE
      return NULL;
  #else
      return DSO_get_filename(prov->module);
  #endif
  }
  
  const char *ossl_provider_module_path(OSSL_PROVIDER *prov)
  {
  #ifdef FIPS_MODE
      return NULL;
  #else
      /* FIXME: Ensure it's a full path */
      return DSO_get_filename(prov->module);
  #endif
  }
  
  /* Wrappers around calls to the provider */
  void ossl_provider_teardown(const OSSL_PROVIDER *prov)
  {
      if (prov->teardown != NULL)
          prov->teardown(prov->provctx);
  }
  
  const OSSL_ITEM *ossl_provider_get_param_types(const OSSL_PROVIDER *prov)
  {
      return prov->get_param_types == NULL
          ? NULL : prov->get_param_types(prov->provctx);
  }
  
  int ossl_provider_get_params(const OSSL_PROVIDER *prov,
                               const OSSL_PARAM params[])
  {
      return prov->get_params == NULL
          ? 0 : prov->get_params(prov->provctx, params);
  }
  
  
  const OSSL_ALGORITHM *ossl_provider_query_operation(const OSSL_PROVIDER *prov,
                                                      int operation_id,
                                                      int *no_cache)
  {
      return prov->query_operation(prov->provctx, operation_id, no_cache);
  }
  
  /*-
   * Core functions for the provider
   * ===============================
   *
   * This is the set of functions that the core makes available to the provider
   */
  
  /*
   * This returns a list of Provider Object parameters with their types, for
   * discovery.  We do not expect that many providers will use this, but one
   * never knows.
   */
  static const OSSL_ITEM param_types[] = {
      { OSSL_PARAM_UTF8_PTR, "openssl-version" },
      { OSSL_PARAM_UTF8_PTR, "provider-name" },
      { 0, NULL }
  };
  
  static const OSSL_ITEM *core_get_param_types(const OSSL_PROVIDER *prov)
  {
      return param_types;
  }
  
  static int core_get_params(const OSSL_PROVIDER *prov, const OSSL_PARAM params[])
  {
      int i;
      const OSSL_PARAM *p;
  
      if ((p = OSSL_PARAM_locate(params, "openssl-version")) != NULL)
          OSSL_PARAM_set_utf8_ptr(p, OPENSSL_VERSION_STR);
      if ((p = OSSL_PARAM_locate(params, "provider-name")) != NULL)
          OSSL_PARAM_set_utf8_ptr(p, prov->name);
  
      if (prov->parameters == NULL)
          return 1;
  
      for (i = 0; i < sk_INFOPAIR_num(prov->parameters); i++) {
          INFOPAIR *pair = sk_INFOPAIR_value(prov->parameters, i);
  
          if ((p = OSSL_PARAM_locate(params, pair->name)) != NULL)
              OSSL_PARAM_set_utf8_ptr(p, pair->value);
      }
  
      return 1;
  }
  
  static const OSSL_DISPATCH core_dispatch_[] = {
      { OSSL_FUNC_CORE_GET_PARAM_TYPES, (void (*)(void))core_get_param_types },
      { OSSL_FUNC_CORE_GET_PARAMS, (void (*)(void))core_get_params },
      { OSSL_FUNC_CORE_PUT_ERROR, (void (*)(void))ERR_put_error },
      { OSSL_FUNC_CORE_ADD_ERROR_VDATA, (void (*)(void))ERR_add_error_vdata },
      { 0, NULL }
  };
  static const OSSL_DISPATCH *core_dispatch = core_dispatch_;
  