Re: Fw: Reg: Memory leaks Using OpenSSL API - Unsure

[pauli@xxxxxxxxxxx]

    Any chance of running your server under valgrind or similar?
    This should make the leaks more concrete.
    
    
    Pauli

On 10/4/22 6:07 pm, Ram Chandra via openssl-users wrote:

Hi, 

I have recently started developing using OpenSSL and i am confused/unclear about below topic.

Request you to help me.

I am running a DTLS Server which handles more than 1000 connections.

The problem i am facing is every time I close connections and also connect again I see there is some RAM memory utilization increases.

I wonder there is a leak in memory from my below approach of calling functions

"Initialize_Sever_Context" , 

"create_connexion" and 

"close_connexion". 

The exact code is too big to create actual scenario, so i just outlined the steps.

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);

X509_VERIFY_PARAM_free(local_vpm);

}

create_connexion(connect_info)

{

    // server_ctx is global

    ssl = SSL_new(server_ctx);

    

    bio = BIO_new_dgram(handler, BIO_NOCLOSE); //not sure it is ok to use BIO_CLOSE

    ..

    ..

    SSL_set_bio(ssl, bio, bio);

    

    connect_info->ssl = ssl;

    connect_info->bio = bio;

}

//pre connection close

handle_closed_connexions()

{

    for(conn = 1; conn<MAX_CONN;conn++)

    {

        close_connexion(connect_info[conn]);

    }

}

// frees the existing closed connections and make SSL ready to handle new connections

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

    // frees the server_ctx also from inside

    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.

So i expect the application to crash.(because "server_ctx" is a global pointer which will be set to "s->ctx" through function SSL_new and also freed by SLL_free and after free i am not setting

server_ctx = NULL also not calling SSL_CTX_new(DTLS_server_method());)

But my application is working fine.

My doubt is , does OpenSSL cache the context detail inside SSL, some where?

or 

I Should set server_context to NULL and allocate memory for every new connection which was closed before?

Regards,

Chand