/*

 * Copyright 1995-2018 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 "internal/cryptlib_int.h"

#include "internal/thread_once.h"

/*

 * Each structure type (sometimes called a class), that supports

 * exdata has a stack of callbacks for each instance.

 */

struct ex_callback_st {

    long argl;                  /* Arbitrary long */

    void *argp;                 /* Arbitrary void * */

    CRYPTO_EX_new *new_func;

    CRYPTO_EX_free *free_func;

    CRYPTO_EX_dup *dup_func;

};

/*

 * The state for each class.  This could just be a typedef, but

 * a structure allows future changes.

 */

typedef struct ex_callbacks_st {

    STACK_OF(EX_CALLBACK) *meth;

} EX_CALLBACKS;

static EX_CALLBACKS ex_data[CRYPTO_EX_INDEX__COUNT];

static CRYPTO_RWLOCK *ex_data_lock = NULL;

static CRYPTO_ONCE ex_data_init = CRYPTO_ONCE_STATIC_INIT;

DEFINE_RUN_ONCE_STATIC(do_ex_data_init)

{

    if (!OPENSSL_init_crypto(0, NULL))

        return 0;

    ex_data_lock = CRYPTO_THREAD_lock_new();

    return ex_data_lock != NULL;

}

/*

 * Return the EX_CALLBACKS from the |ex_data| array that corresponds to

 * a given class.  On success, *holds the lock.*

 */

static EX_CALLBACKS *get_and_lock(int class_index)

{

    EX_CALLBACKS *ip;

    if (class_index < 0 || class_index >= CRYPTO_EX_INDEX__COUNT) {

        CRYPTOerr(CRYPTO_F_GET_AND_LOCK, ERR_R_PASSED_INVALID_ARGUMENT);

        return NULL;

    }

    if (!RUN_ONCE(&ex_data_init, do_ex_data_init)) {

        CRYPTOerr(CRYPTO_F_GET_AND_LOCK, ERR_R_MALLOC_FAILURE);

        return NULL;

    }

    if (ex_data_lock == NULL) {

        /*

         * This can happen in normal operation when using CRYPTO_mem_leaks().

         * The CRYPTO_mem_leaks() function calls OPENSSL_cleanup() which cleans

         * up the locks. Subsequently the BIO that CRYPTO_mem_leaks() uses gets

         * freed, which also attempts to free the ex_data. However

         * CRYPTO_mem_leaks() ensures that the ex_data is freed early (i.e.

         * before OPENSSL_cleanup() is called), so if we get here we can safely

         * ignore this operation. We just treat it as an error.

         */

         return NULL;

    }

    ip = &ex_data[class_index];

    CRYPTO_THREAD_write_lock(ex_data_lock);

    return ip;

}

static void cleanup_cb(EX_CALLBACK *funcs)

{

    OPENSSL_free(funcs);

}

/*

 * Release all "ex_data" state to prevent memory leaks. This can't be made

 * thread-safe without overhauling a lot of stuff, and shouldn't really be

 * called under potential race-conditions anyway (it's for program shutdown

 * after all).

 */

void crypto_cleanup_all_ex_data_int(void)

{

    int i;

    for (i = 0; i < CRYPTO_EX_INDEX__COUNT; ++i) {

        EX_CALLBACKS *ip = &ex_data[i];

        sk_EX_CALLBACK_pop_free(ip->meth, cleanup_cb);

        ip->meth = NULL;

    }

    CRYPTO_THREAD_lock_free(ex_data_lock);

    ex_data_lock = NULL;

}

/*

 * Unregister a new index by replacing the callbacks with no-ops.

 * Any in-use instances are leaked.

 */

static void dummy_new(void *parent, void *ptr, CRYPTO_EX_DATA *ad, int idx,

                     long argl, void *argp)

{

}

static void dummy_free(void *parent, void *ptr, CRYPTO_EX_DATA *ad, int idx,

                       long argl, void *argp)

{

}

static int dummy_dup(CRYPTO_EX_DATA *to, const CRYPTO_EX_DATA *from,

                     void *from_d, int idx,

                     long argl, void *argp)

{

    return 1;

}

int CRYPTO_free_ex_index(int class_index, int idx)

{

    EX_CALLBACKS *ip = get_and_lock(class_index);

    EX_CALLBACK *a;

    int toret = 0;

    if (ip == NULL)

        return 0;

    if (idx < 0 || idx >= sk_EX_CALLBACK_num(ip->meth))

        goto err;

    a = sk_EX_CALLBACK_value(ip->meth, idx);

    if (a == NULL)

        goto err;

    a->new_func = dummy_new;

    a->dup_func = dummy_dup;

    a->free_func = dummy_free;

    toret = 1;

err:

    CRYPTO_THREAD_unlock(ex_data_lock);

    return toret;

}

/*

 * Register a new index.

 */

int CRYPTO_get_ex_new_index(int class_index, long argl, void *argp,

                            CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,

                            CRYPTO_EX_free *free_func)

{

    int toret = -1;

    EX_CALLBACK *a;

    EX_CALLBACKS *ip = get_and_lock(class_index);

    if (ip == NULL)

        return -1;

    if (ip->meth == NULL) {

        ip->meth = sk_EX_CALLBACK_new_null();

        /* We push an initial value on the stack because the SSL

         * "app_data" routines use ex_data index zero.  See RT 3710. */

        if (ip->meth == NULL

            || !sk_EX_CALLBACK_push(ip->meth, NULL)) {

            CRYPTOerr(CRYPTO_F_CRYPTO_GET_EX_NEW_INDEX, ERR_R_MALLOC_FAILURE);

            goto err;

        }

    }

    a = (EX_CALLBACK *)OPENSSL_malloc(sizeof(*a));

    if (a == NULL) {

        CRYPTOerr(CRYPTO_F_CRYPTO_GET_EX_NEW_INDEX, ERR_R_MALLOC_FAILURE);

        goto err;

    }

    a->argl = argl;

    a->argp = argp;

    a->new_func = new_func;

    a->dup_func = dup_func;

    a->free_func = free_func;

    if (!sk_EX_CALLBACK_push(ip->meth, NULL)) {

        CRYPTOerr(CRYPTO_F_CRYPTO_GET_EX_NEW_INDEX, ERR_R_MALLOC_FAILURE);

        OPENSSL_free(a);

        goto err;

    }

    toret = sk_EX_CALLBACK_num(ip->meth) - 1;

    (void)sk_EX_CALLBACK_set(ip->meth, toret, a);

 err:

    CRYPTO_THREAD_unlock(ex_data_lock);

    return toret;

}

/*

 * Initialise a new CRYPTO_EX_DATA for use in a particular class - including

 * calling new() callbacks for each index in the class used by this variable

 * Thread-safe by copying a class's array of "EX_CALLBACK" entries

 * in the lock, then using them outside the lock. Note this only applies

 * to the global "ex_data" state (ie. class definitions), not 'ad' itself.

 */

int CRYPTO_new_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)

{

    int mx, i;

    void *ptr;

    EX_CALLBACK **storage = NULL;

    EX_CALLBACK *stack[10];

    EX_CALLBACKS *ip = get_and_lock(class_index);

    if (ip == NULL)

        return 0;

    ad->sk = NULL;

    mx = sk_EX_CALLBACK_num(ip->meth);

    if (mx > 0) {

        if (mx < (int)OSSL_NELEM(stack))

            storage = stack;

        else

            storage = OPENSSL_malloc(sizeof(*storage) * mx);

        if (storage != NULL)

            for (i = 0; i < mx; i++)

                storage[i] = sk_EX_CALLBACK_value(ip->meth, i);

    }

    CRYPTO_THREAD_unlock(ex_data_lock);

    if (mx > 0 && storage == NULL) {

        CRYPTOerr(CRYPTO_F_CRYPTO_NEW_EX_DATA, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    for (i = 0; i < mx; i++) {

        if (storage[i] && storage[i]->new_func) {

            ptr = CRYPTO_get_ex_data(ad, i);

            storage[i]->new_func(obj, ptr, ad, i,

                                 storage[i]->argl, storage[i]->argp);

        }

    }

    if (storage != stack)

        OPENSSL_free(storage);

    return 1;

}

/*

 * Duplicate a CRYPTO_EX_DATA variable - including calling dup() callbacks

 * for each index in the class used by this variable

 */

int CRYPTO_dup_ex_data(int class_index, CRYPTO_EX_DATA *to,

                       const CRYPTO_EX_DATA *from)

{

    int mx, j, i;

    void *ptr;

    EX_CALLBACK *stack[10];

    EX_CALLBACK **storage = NULL;

    EX_CALLBACKS *ip;

    int toret = 0;

    if (from->sk == NULL)

        /* Nothing to copy over */

        return 1;

    if ((ip = get_and_lock(class_index)) == NULL)

        return 0;

    mx = sk_EX_CALLBACK_num(ip->meth);

    j = sk_void_num(from->sk);

    if (j < mx)

        mx = j;

    if (mx > 0) {

        if (mx < (int)OSSL_NELEM(stack))

            storage = stack;

        else

            storage = OPENSSL_malloc(sizeof(*storage) * mx);

        if (storage != NULL)

            for (i = 0; i < mx; i++)

                storage[i] = sk_EX_CALLBACK_value(ip->meth, i);

    }

    CRYPTO_THREAD_unlock(ex_data_lock);

    if (mx == 0)

        return 1;

    if (storage == NULL) {

        CRYPTOerr(CRYPTO_F_CRYPTO_DUP_EX_DATA, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    /*

     * Make sure the ex_data stack is at least |mx| elements long to avoid

     * issues in the for loop that follows; so go get the |mx|'th element

     * (if it does not exist CRYPTO_get_ex_data() returns NULL), and assign

     * to itself. This is normally a no-op; but ensures the stack is the

     * proper size

     */

    if (!CRYPTO_set_ex_data(to, mx - 1, CRYPTO_get_ex_data(to, mx - 1)))

        goto err;

    for (i = 0; i < mx; i++) {

        ptr = CRYPTO_get_ex_data(from, i);

        if (storage[i] && storage[i]->dup_func)

            if (!storage[i]->dup_func(to, from, &ptr, i,

                                      storage[i]->argl, storage[i]->argp))

                goto err;

        CRYPTO_set_ex_data(to, i, ptr);

    }

    toret = 1;

 err:

    if (storage != stack)

        OPENSSL_free(storage);

    return toret;

}

/*

 * Cleanup a CRYPTO_EX_DATA variable - including calling free() callbacks for

 * each index in the class used by this variable

 */

void CRYPTO_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)

{

    int mx, i;

    EX_CALLBACKS *ip;

    void *ptr;

    EX_CALLBACK *f;

    EX_CALLBACK *stack[10];

    EX_CALLBACK **storage = NULL;

    if ((ip = get_and_lock(class_index)) == NULL)

        goto err;

    mx = sk_EX_CALLBACK_num(ip->meth);

    if (mx > 0) {

        if (mx < (int)OSSL_NELEM(stack))

            storage = stack;

        else

            storage = OPENSSL_malloc(sizeof(*storage) * mx);

        if (storage != NULL)

            for (i = 0; i < mx; i++)

                storage[i] = sk_EX_CALLBACK_value(ip->meth, i);

    }

    CRYPTO_THREAD_unlock(ex_data_lock);

    for (i = 0; i < mx; i++) {

        if (storage != NULL)

            f = storage[i];

        else {

            CRYPTO_THREAD_write_lock(ex_data_lock);

            f = sk_EX_CALLBACK_value(ip->meth, i);

            CRYPTO_THREAD_unlock(ex_data_lock);

        }

        if (f != NULL && f->free_func != NULL) {

            ptr = CRYPTO_get_ex_data(ad, i);

            f->free_func(obj, ptr, ad, i, f->argl, f->argp);

        }

    }

    if (storage != stack)

        OPENSSL_free(storage);

 err:

    sk_void_free(ad->sk);

    ad->sk = NULL;

}

/*

 * For a given CRYPTO_EX_DATA variable, set the value corresponding to a

 * particular index in the class used by this variable

 */

int CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int idx, void *val)

{

    int i;

    if (ad->sk == NULL) {

        if ((ad->sk = sk_void_new_null()) == NULL) {

            CRYPTOerr(CRYPTO_F_CRYPTO_SET_EX_DATA, ERR_R_MALLOC_FAILURE);

            return 0;

        }

    }

    for (i = sk_void_num(ad->sk); i <= idx; ++i) {

        if (!sk_void_push(ad->sk, NULL)) {

            CRYPTOerr(CRYPTO_F_CRYPTO_SET_EX_DATA, ERR_R_MALLOC_FAILURE);

            return 0;

        }

    }

    sk_void_set(ad->sk, idx, val);

    return 1;

}

/*

 * For a given CRYPTO_EX_DATA_ variable, get the value corresponding to a

 * particular index in the class used by this variable

 */

void *CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int idx)

{

    if (ad->sk == NULL || idx >= sk_void_num(ad->sk))

        return NULL;

    return sk_void_value(ad->sk, idx);

}