/*

 * Copyright 2018-2023 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/safestack.h>

#include <openssl/store.h>

#include "internal/cryptlib.h"

#include "crypto/x509.h"

#include "x509_local.h"

typedef struct cached_store_st {

    char *uri;

    OSSL_LIB_CTX *libctx;

    char *propq;

    OSSL_STORE_CTX *ctx;

} CACHED_STORE;

DEFINE_STACK_OF(CACHED_STORE)

/* Generic object loader, given expected type and criterion */

static int cache_objects(X509_LOOKUP *lctx, CACHED_STORE *store,

                         const OSSL_STORE_SEARCH *criterion, int depth)

{

    int ok = 0;

    OSSL_STORE_CTX *ctx = store->ctx;

    X509_STORE *xstore = X509_LOOKUP_get_store(lctx);

    if (ctx == NULL

        && (ctx = OSSL_STORE_open_ex(store->uri, store->libctx, store->propq,

                                     NULL, NULL, NULL, NULL, NULL)) == NULL)

        return 0;

    store->ctx = ctx;

    /*

     * We try to set the criterion, but don't care if it was valid or not.

     * For an OSSL_STORE, it merely serves as an optimization, the expectation

     * being that if the criterion couldn't be used, we will get *everything*

     * from the container that the URI represents rather than the subset that

     * the criterion indicates, so the biggest harm is that we cache more

     * objects certs and CRLs than we may expect, but that's ok.

     *

     * Specifically for OpenSSL's own file: scheme, the only workable

     * criterion is the BY_NAME one, which it can only apply on directories,

     * but it's possible that the URI is a single file rather than a directory,

     * and in that case, the BY_NAME criterion is pointless.

     *

     * We could very simply not apply any criterion at all here, and just let

     * the code that selects certs and CRLs from the cached objects do its job,

     * but it's a nice optimization when it can be applied (such as on an

     * actual directory with a thousand CA certs).

     */

    if (criterion != NULL)

        OSSL_STORE_find(ctx, criterion);

    for (;;) {

        OSSL_STORE_INFO *info = OSSL_STORE_load(ctx);

        int infotype;

        /* NULL means error or "end of file".  Either way, we break. */

        if (info == NULL)

            break;

        infotype = OSSL_STORE_INFO_get_type(info);

        ok = 0;

        if (infotype == OSSL_STORE_INFO_NAME) {

            /*

             * This is an entry in the "directory" represented by the current

             * uri.  if |depth| allows, dive into it.

             */

            if (depth > 0) {

                CACHED_STORE substore;

                substore.uri = (char *)OSSL_STORE_INFO_get0_NAME(info);

                substore.libctx = store->libctx;

                substore.propq = store->propq;

                substore.ctx = NULL;

                ok = cache_objects(lctx, &substore, criterion, depth - 1);

            }

        } else {

            /*

             * We know that X509_STORE_add_{cert|crl} increments the object's

             * refcount, so we can safely use OSSL_STORE_INFO_get0_{cert,crl}

             * to get them.

             */

            switch (infotype) {

            case OSSL_STORE_INFO_CERT:

                ok = X509_STORE_add_cert(xstore,

                                         OSSL_STORE_INFO_get0_CERT(info));

                break;

            case OSSL_STORE_INFO_CRL:

                ok = X509_STORE_add_crl(xstore,

                                        OSSL_STORE_INFO_get0_CRL(info));

                break;

            }

        }

        OSSL_STORE_INFO_free(info);

        if (!ok)

            break;

    }

    OSSL_STORE_close(ctx);

    store->ctx = NULL;

    return ok;

}

static void free_store(CACHED_STORE *store)

{

    if (store != NULL) {

        OSSL_STORE_close(store->ctx);

        OPENSSL_free(store->uri);

        OPENSSL_free(store->propq);

        OPENSSL_free(store);

    }

}

static void by_store_free(X509_LOOKUP *ctx)

{

    STACK_OF(CACHED_STORE) *stores = X509_LOOKUP_get_method_data(ctx);

    sk_CACHED_STORE_pop_free(stores, free_store);

}

static int by_store_ctrl_ex(X509_LOOKUP *ctx, int cmd, const char *argp,

                            long argl, char **retp, OSSL_LIB_CTX *libctx,

                            const char *propq)

{

    /*

     * In some cases below, failing to use the defaults shouldn't result in

     * an error.  |use_default| is used as the return code in those cases.

     */

    int use_default = argp == NULL;

    switch (cmd) {

    case X509_L_ADD_STORE:

        /* If no URI is given, use the default cert dir as default URI */

        if (argp == NULL)

            argp = ossl_safe_getenv(X509_get_default_cert_dir_env());

        if (argp == NULL)

            argp = X509_get_default_cert_dir();

        {

            STACK_OF(CACHED_STORE) *stores = X509_LOOKUP_get_method_data(ctx);

            CACHED_STORE *store = OPENSSL_zalloc(sizeof(*store));

            if (store == NULL) {

                return 0;

            }

            store->uri = OPENSSL_strdup(argp);

            store->libctx = libctx;

            if (propq != NULL)

                store->propq = OPENSSL_strdup(propq);

            store->ctx = OSSL_STORE_open_ex(argp, libctx, propq, NULL, NULL,

                                           NULL, NULL, NULL);

            if (store->ctx == NULL

                || (propq != NULL && store->propq == NULL)

                || store->uri == NULL) {

                free_store(store);

                return use_default;

            }

            if (stores == NULL) {

                stores = sk_CACHED_STORE_new_null();

                if (stores != NULL)

                    X509_LOOKUP_set_method_data(ctx, stores);

            }

            if (stores == NULL || sk_CACHED_STORE_push(stores, store) <= 0) {

                free_store(store);

                return 0;

            }

            return 1;

        }

    case X509_L_LOAD_STORE: {

        /* This is a shortcut for quick loading of specific containers */

        CACHED_STORE store;

        store.uri = (char *)argp;

        store.libctx = libctx;

        store.propq = (char *)propq;

        store.ctx = NULL;

        return cache_objects(ctx, &store, NULL, 0);

    }

    default:

        /* Unsupported command */

        return 0;

    }

    return 0;

}

static int by_store_ctrl(X509_LOOKUP *ctx, int cmd,

                         const char *argp, long argl, char **retp)

{

    return by_store_ctrl_ex(ctx, cmd, argp, argl, retp, NULL, NULL);

}

static int by_store(X509_LOOKUP *ctx, X509_LOOKUP_TYPE type,

                    const OSSL_STORE_SEARCH *criterion, X509_OBJECT *ret)

{

    STACK_OF(CACHED_STORE) *stores = X509_LOOKUP_get_method_data(ctx);

    int i;

    int ok = 0;

    for (i = 0; i < sk_CACHED_STORE_num(stores); i++) {

        ok = cache_objects(ctx, sk_CACHED_STORE_value(stores, i), criterion,

                           1 /* depth */);

        if (ok)

            break;

    }

    return ok;

}

static int by_store_subject(X509_LOOKUP *ctx, X509_LOOKUP_TYPE type,

                            const X509_NAME *name, X509_OBJECT *ret)

{

    OSSL_STORE_SEARCH *criterion =

        OSSL_STORE_SEARCH_by_name((X509_NAME *)name); /* won't modify it */

    int ok = by_store(ctx, type, criterion, ret);

    STACK_OF(X509_OBJECT) *store_objects =

        X509_STORE_get0_objects(X509_LOOKUP_get_store(ctx));

    X509_OBJECT *tmp = NULL;

    OSSL_STORE_SEARCH_free(criterion);

    if (ok)

        tmp = X509_OBJECT_retrieve_by_subject(store_objects, type, name);

    ok = 0;

    if (tmp != NULL) {

        /*

         * This could also be done like this:

         *

         *     if (tmp != NULL) {

         *         *ret = *tmp;

         *         ok = 1;

         *     }

         *

         * However, we want to exercise the documented API to the max, so

         * we do it the hard way.

         *

         * To be noted is that X509_OBJECT_set1_* increment the refcount,

         * but so does X509_STORE_CTX_get_by_subject upon return of this

         * function, so we must ensure the refcount is decremented

         * before we return, or we will get a refcount leak.  We cannot do

         * this with X509_OBJECT_free(), though, as that will free a bit

         * too much.

         */

        switch (type) {

        case X509_LU_X509:

            ok = X509_OBJECT_set1_X509(ret, tmp->data.x509);

            if (ok)

                X509_free(tmp->data.x509);

            break;

        case X509_LU_CRL:

            ok = X509_OBJECT_set1_X509_CRL(ret, tmp->data.crl);

            if (ok)

                X509_CRL_free(tmp->data.crl);

            break;

        case X509_LU_NONE:

            break;

        }

    }

    return ok;

}

/*

 * We lack the implementations for get_by_issuer_serial, get_by_fingerprint

 * and get_by_alias.  There's simply not enough support in the X509_LOOKUP

 * or X509_STORE APIs.

 */

static X509_LOOKUP_METHOD x509_store_lookup = {

    "Load certs from STORE URIs",

    NULL,                        /* new_item */

    by_store_free,               /* free */

    NULL,                        /* init */

    NULL,                        /* shutdown */

    by_store_ctrl,               /* ctrl */

    by_store_subject,            /* get_by_subject */

    NULL,                        /* get_by_issuer_serial */

    NULL,                        /* get_by_fingerprint */

    NULL,                        /* get_by_alias */

    NULL,                        /* get_by_subject_ex */

    by_store_ctrl_ex

};

X509_LOOKUP_METHOD *X509_LOOKUP_store(void)

{

    return &x509_store_lookup;

}