Do I need to call BIO_free(network_bio) or not?

[Iñaki Baz Castillo]

Hi, I'm a bit confused about how to free a BIO pair associated to a SSL.

The doc at https://www.openssl.org/docs/crypto/BIO_s_bio.html clearly says:

----------------------------
Both halves of a BIO pair should be freed. That is even if one half is
implicit freed due to a BIO_free_all() or SSL_free() call the other
half needs to be freed.

EXAMPLE

BIO *internal_bio, *network_bio;
BIO_new_bio_pair(internal_bio, 0, network_bio, 0);
SSL_set_bio(ssl, internal_bio, internal_bio);
...
SSL_free(ssl);                /* implicitly frees internal_bio */
BIO_free(network_bio);
----------------------------


Is it true that I must call to BIO_free(network_bio)? The SSL_free()
code "seems" to do it by itself!:

--------------------------
void SSL_free(SSL *s)
{
   ...
   if (s->rbio != NULL)
       BIO_free_all(s->rbio);
   if ((s->wbio != NULL) && (s->wbio != s->rbio))
       BIO_free_all(s->wbio);
--------------------------

In my code I get an obvious crash if I call BIO_free(internal_bio)
after SSL_free(ssl), but I do NOT get a crash if I call
BIO_free(network_bio).


Anyhow in my code I do not use BIO_new_bio_pair() but instead:

------------------------
BIO* internal_bio = BIO_new(BIO_s_mem());
BIO* network_bio = BIO_new(BIO_s_mem());
SSL_set_bio(ssl, internal_bio, network_bio);

void destroy() {
  if (ssl) {
      SSL_free(ssl);
  }


  // This does NOT crash but, should I do it or not? leak otherwise?
  if (write_bio) {
      BIO_free(write_bio);
  }
}
------------------------


Thanks a lot.




-- 
Iñaki Baz Castillo
<i...@aliax.net>
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