Memory 泄漏使用 OpenSSL API

Question

I am running a DTLS Server which handles more than 500 connections, every time some connections are closed i see there is some RAM memory utilization increases.

I wonder there is a leak in memory from my below approach of Initialize_Sever_Context, create_connexion and close_connexion. The exact code is too big to create actual scenario, so i just outlined the step.

Pls let me know if any extra information is required?

I am using OpenSSL version 1.1.1k on Linux.

//connect_info structure user defined
{
 void* sll;
 void* bio;
 ....
}array_of_connections

*connect_info = &array_of_connections;
// global
SSL_CTX* server_ctx;

Initialize_Sever_Context()
{
    // server_ctx is global 
    server_ctx = SSL_CTX_new(DTLS_server_method());
    X509_VERIFY_PARAM *local_vpm = X509_VERIFY_PARAM_new()

    //setting verify flags, cookie flags and cypher lists etc..
    //....
    SSL_CTX_set1_param(server_ctx, local_vpm);
}

create_connexion(connect_info)
{
    // server_ctx is global
    ssl = SSL_new(server_ctx);
    
    bio = BIO_new_dgram(handler, BIO_NOCLOSE);
    ..
    ..
    SSL_set_bio(ssl, bio, bio);
    
    connect_info->ssl = ssl;
    connect_info->bio = bio;

}

handle_closed_connexions()
{
    for(conn = 1; conn<MAX_CONN;conn++)
    {
        close_connexion(connect_info[conn]);
    }
}

close_connexion(connect_info)
{
    // store prev ssl objects
    SLL *local_ssl = connect_info -> ssl;
    
    // make setup ready for the next connexions
    // and start listening
    create_connexion(connect_info)

    // free the previous closed connections
    SSL_free(local_ssl);
}

Inside SSL_free we have BIO_free_all(s->rbio), BIO_free_all(s->rbio) and BIO_CTX_free(s->ctx) and finally OPENSSL_free(s)

As far as i understand when we do SSL_free, all the members(pointers) inside SLL object are freed. But inside OpenSSL non of pointers are set to NULL after free(), so i expect the application to crash.

But my application is working even after the pointers are freed.

Why does not OpenSSL set the pointers to NULL after they are freed or Can i assume that my application is Safe with the above approach?

I have checked posts 1 2 and others, but none of them satisfy my requirement, so i am asking a new question.

Answer 1

Why does not OpenSSL set the pointers to NULL after they are freed or Can i assume that my application is Safe with the above approach?

99.99% of the time, the pointers aren't going to be accessed again, so setting them to NULL serves no purpose. If you do happen to need them set to NULL , then you can set them to NULL .