Memory leak because of using openssl encryption

[vschreiner]

I experienced two memory leaks when I am using the rabbitmq-c with encrypted connection. I am using libssl. I was able to fix the leaks that occured in hostname_matches_subject_alt_name and amqp_ssl_socket_verify_hostname in amqp_openssl.c.

I changed the methods to look like follows:

static int hostname_matches_subject_alt_name(const char *hostname, X509 *cert)
{
  int found_any_entries = 0;
  int found_match;
  GENERAL_NAME *namePart = NULL;
  STACK_OF(GENERAL_NAME) *san =
    (STACK_OF(GENERAL_NAME)*) X509_get_ext_d2i(cert, NID_subject_alt_name, NULL, NULL);

  while (sk_GENERAL_NAME_num(san) > 0)
  {
    namePart = sk_GENERAL_NAME_pop(san);

    if (namePart->type == GEN_DNS) {
      found_any_entries = 1;
      found_match = match(namePart->d.uniformResourceIdentifier, hostname);
      if (found_match)
        return 1;
    }
  }

  return (found_any_entries ? 0 : -1);
}

and

static int
amqp_ssl_socket_verify_hostname(void *base, const char *host)
{
  struct amqp_ssl_socket_t *self = (struct amqp_ssl_socket_t *)base;
  int status = 0;
  X509 *cert=NULL;
  int res;
  cert = SSL_get_peer_certificate(self->ssl);
  if (!cert) {
    goto error;
  }
  res = hostname_matches_subject_alt_name(host, cert);
  if (res != 1) {
    res = hostname_matches_subject_common_name(host, cert);
    if (!res)
      goto error;
  }
exit:
  X509_free(cert);
  return status;
error:
  if(cert!=NULL)
      X509_free(cert);
  status = -1;
  goto exit;
}

After I recompiled librabbitmq-c and rerun the application using valgrind the memory leaks were gone.

kind regards

Volker Schreiner

AMAN Media GmbH
https://www.aman.de

[alanxz]

I've figured out your changes in amqp_ssl_socket_verify_hostname.

What did you change about hostname_matches_subject_alt_name? The function looks identical to the current code.

[vschreiner]

I added the

X509_free(cert);

and

if(cert!=NULL)
X509_free(cert);

lines which were missing in the 0.7.1 release.

AMAN Media GmbH
https://www.aman.de

[alanxz]

Fix is now in place. Thanks for reporting it.