/*
 * Copyright 2019-2021 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 <string.h>
#include <openssl/trace.h>
#include <openssl/err.h>
#include <openssl/conf.h>
#include <openssl/safestack.h>
#include <openssl/provider.h>
#include "internal/provider.h"
#include "internal/cryptlib.h"
#include "provider_local.h"

DEFINE_STACK_OF(OSSL_PROVIDER)

/* PROVIDER config module */

typedef struct {
    CRYPTO_RWLOCK *lock;
    STACK_OF(OSSL_PROVIDER) *activated_providers;
} PROVIDER_CONF_GLOBAL;

static void *prov_conf_ossl_ctx_new(OSSL_LIB_CTX *libctx)
{
    PROVIDER_CONF_GLOBAL *pcgbl = OPENSSL_zalloc(sizeof(*pcgbl));

    if (pcgbl == NULL)
        return NULL;

    pcgbl->lock = CRYPTO_THREAD_lock_new();
    if (pcgbl->lock == NULL) {
        OPENSSL_free(pcgbl);
        return NULL;
    }

    return pcgbl;
}

static void prov_conf_ossl_ctx_free(void *vpcgbl)
{
    PROVIDER_CONF_GLOBAL *pcgbl = vpcgbl;

    sk_OSSL_PROVIDER_pop_free(pcgbl->activated_providers,
                              ossl_provider_free);

    OSSL_TRACE(CONF, "Cleaned up providers\n");
    CRYPTO_THREAD_lock_free(pcgbl->lock);
    OPENSSL_free(pcgbl);
}

static const OSSL_LIB_CTX_METHOD provider_conf_ossl_ctx_method = {
    /* Must be freed before the provider store is freed */
    OSSL_LIB_CTX_METHOD_PRIORITY_2,
    prov_conf_ossl_ctx_new,
    prov_conf_ossl_ctx_free,
};

static const char *skip_dot(const char *name)
{
    const char *p = strchr(name, '.');

    if (p != NULL)
        return p + 1;
    return name;
}

static int provider_conf_params(OSSL_PROVIDER *prov,
                                OSSL_PROVIDER_INFO *provinfo,
                                const char *name, const char *value,
                                const CONF *cnf)
{
    STACK_OF(CONF_VALUE) *sect;
    int ok = 1;

    sect = NCONF_get_section(cnf, value);
    if (sect != NULL) {
        int i;
        char buffer[512];
        size_t buffer_len = 0;

        OSSL_TRACE1(CONF, "Provider params: start section %s\n", value);

        if (name != NULL) {
            OPENSSL_strlcpy(buffer, name, sizeof(buffer));
            OPENSSL_strlcat(buffer, ".", sizeof(buffer));
            buffer_len = strlen(buffer);
        }

        for (i = 0; i < sk_CONF_VALUE_num(sect); i++) {
            CONF_VALUE *sectconf = sk_CONF_VALUE_value(sect, i);

            if (buffer_len + strlen(sectconf->name) >= sizeof(buffer))
                return 0;
            buffer[buffer_len] = '\0';
            OPENSSL_strlcat(buffer, sectconf->name, sizeof(buffer));
            if (!provider_conf_params(prov, provinfo, buffer, sectconf->value,
                                      cnf))
                return 0;
        }

        OSSL_TRACE1(CONF, "Provider params: finish section %s\n", value);
    } else {
        OSSL_TRACE2(CONF, "Provider params: %s = %s\n", name, value);
        if (prov != NULL)
            ok = ossl_provider_add_parameter(prov, name, value);
        else
            ok = ossl_provider_info_add_parameter(provinfo, name, value);
    }

    return ok;
}

static int prov_already_activated(const char *name,
                                  STACK_OF(OSSL_PROVIDER) *activated)
{
    int i, max;

    if (activated == NULL)
        return 0;

    max = sk_OSSL_PROVIDER_num(activated);
    for (i = 0; i < max; i++) {
        OSSL_PROVIDER *tstprov = sk_OSSL_PROVIDER_value(activated, i);

        if (strcmp(OSSL_PROVIDER_get0_name(tstprov), name) == 0) {
            return 1;
        }
    }

    return 0;
}

static int provider_conf_activate(OSSL_LIB_CTX *libctx, const char *name,
                                  const char *value, const char *path,
                                  int soft, const CONF *cnf)
{
    PROVIDER_CONF_GLOBAL *pcgbl
        = ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_PROVIDER_CONF_INDEX,
                                &provider_conf_ossl_ctx_method);
    OSSL_PROVIDER *prov = NULL, *actual = NULL;
    int ok = 0;

    if (pcgbl == NULL || !CRYPTO_THREAD_write_lock(pcgbl->lock)) {
        ERR_raise(ERR_LIB_CRYPTO, ERR_R_INTERNAL_ERROR);
        return 0;
    }
    if (!prov_already_activated(name, pcgbl->activated_providers)) {
        /*
        * There is an attempt to activate a provider, so we should disable
        * loading of fallbacks. Otherwise a misconfiguration could mean the
        * intended provider does not get loaded. Subsequent fetches could
        * then fallback to the default provider - which may be the wrong
        * thing.
        */
        if (!ossl_provider_disable_fallback_loading(libctx)) {
            CRYPTO_THREAD_unlock(pcgbl->lock);
            ERR_raise(ERR_LIB_CRYPTO, ERR_R_INTERNAL_ERROR);
            return 0;
        }
        prov = ossl_provider_find(libctx, name, 1);
        if (prov == NULL)
            prov = ossl_provider_new(libctx, name, NULL, 1);
        if (prov == NULL) {
            CRYPTO_THREAD_unlock(pcgbl->lock);
            if (soft)
                ERR_clear_error();
            return 0;
        }

        if (path != NULL)
            ossl_provider_set_module_path(prov, path);

        ok = provider_conf_params(prov, NULL, NULL, value, cnf);

        if (ok) {
            if (!ossl_provider_activate(prov, 1, 0)) {
                ok = 0;
            } else if (!ossl_provider_add_to_store(prov, &actual, 0)) {
                ossl_provider_deactivate(prov, 1);
                ok = 0;
            } else if (actual != prov
                       && !ossl_provider_activate(actual, 1, 0)) {
                ossl_provider_free(actual);
                ok = 0;
            } else {
                if (pcgbl->activated_providers == NULL)
                    pcgbl->activated_providers = sk_OSSL_PROVIDER_new_null();
                if (pcgbl->activated_providers == NULL
                    || !sk_OSSL_PROVIDER_push(pcgbl->activated_providers,
                                              actual)) {
                    ossl_provider_deactivate(actual, 1);
                    ossl_provider_free(actual);
                    ok = 0;
                } else {
                    ok = 1;
                }
            }
        }
        if (!ok)
            ossl_provider_free(prov);
    }
    CRYPTO_THREAD_unlock(pcgbl->lock);

    return ok;
}

static int provider_conf_load(OSSL_LIB_CTX *libctx, const char *name,
                              const char *value, const CONF *cnf)
{
    int i;
    STACK_OF(CONF_VALUE) *ecmds;
    int soft = 0;
    const char *path = NULL;
    long activate = 0;
    int ok = 0;

    name = skip_dot(name);
    OSSL_TRACE1(CONF, "Configuring provider %s\n", name);
    /* Value is a section containing PROVIDER commands */
    ecmds = NCONF_get_section(cnf, value);

    if (!ecmds) {
        ERR_raise_data(ERR_LIB_CRYPTO, CRYPTO_R_PROVIDER_SECTION_ERROR,
                       "section=%s not found", value);
        return 0;
    }

    /* Find the needed data first */
    for (i = 0; i < sk_CONF_VALUE_num(ecmds); i++) {
        CONF_VALUE *ecmd = sk_CONF_VALUE_value(ecmds, i);
        const char *confname = skip_dot(ecmd->name);
        const char *confvalue = ecmd->value;

        OSSL_TRACE2(CONF, "Provider command: %s = %s\n",
                    confname, confvalue);

        /* First handle some special pseudo confs */

        /* Override provider name to use */
        if (strcmp(confname, "identity") == 0)
            name = confvalue;
        else if (strcmp(confname, "soft_load") == 0)
            soft = 1;
        /* Load a dynamic PROVIDER */
        else if (strcmp(confname, "module") == 0)
            path = confvalue;
        else if (strcmp(confname, "activate") == 0)
            activate = 1;
    }

    if (activate) {
        ok = provider_conf_activate(libctx, name, value, path, soft, cnf);
    } else {
        OSSL_PROVIDER_INFO entry;

        memset(&entry, 0, sizeof(entry));
        ok = 1;
        if (name != NULL) {
            entry.name = OPENSSL_strdup(name);
            if (entry.name == NULL) {
                ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
                ok = 0;
            }
        }
        if (ok && path != NULL) {
            entry.path = OPENSSL_strdup(path);
            if (entry.path == NULL) {
                ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
                ok = 0;
            }
        }
        if (ok)
            ok = provider_conf_params(NULL, &entry, NULL, value, cnf);
        if (ok && (entry.path != NULL || entry.parameters != NULL))
            ok = ossl_provider_info_add_to_store(libctx, &entry);
        if (!ok || (entry.path == NULL && entry.parameters == NULL)) {
            ossl_provider_info_clear(&entry);
        }

    }

    /*
     * Even if ok is 0, we still return success. Failure to load a provider is
     * not fatal. We want to continue to load the rest of the config file.
     */
    return 1;
}

static int provider_conf_init(CONF_IMODULE *md, const CONF *cnf)
{
    STACK_OF(CONF_VALUE) *elist;
    CONF_VALUE *cval;
    int i;

    OSSL_TRACE1(CONF, "Loading providers module: section %s\n",
                CONF_imodule_get_value(md));

    /* Value is a section containing PROVIDERs to configure */
    elist = NCONF_get_section(cnf, CONF_imodule_get_value(md));

    if (!elist) {
        ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_PROVIDER_SECTION_ERROR);
        return 0;
    }

    for (i = 0; i < sk_CONF_VALUE_num(elist); i++) {
        cval = sk_CONF_VALUE_value(elist, i);
        if (!provider_conf_load(NCONF_get0_libctx((CONF *)cnf),
                    cval->name, cval->value, cnf))
            return 0;
    }

    return 1;
}

void ossl_provider_add_conf_module(void)
{
    OSSL_TRACE(CONF, "Adding config module 'providers'\n");
    CONF_module_add("providers", provider_conf_init, NULL);
}