Bug#25203 Mysql crashes when mysql_kill() is executed in a connection using SSL

 - It's too early to free the SSL object in 'vio_ssl_close'. There
   might still be a thread using or reading from it on platforms
   where we need to close the active connection/socket in order
   to break the read.  
 - Add new function 'vio_ssl_delete' and install it as the viodelete
   function for SSL connections.


vio/vio.c:
  Install 'vio_ssl_delete' as viodelete function for SSL connections
  Cleanup 'vio_delete'
vio/vio_priv.h:
  Add declaration of vio_ssl_delete
vio/viossl.c:
  Add new function 'vio_ssl_delete' that takes care of freeing the memory
  allocated by the SSL connection
  Move the code to free the SSL object from vio_ssl_close

1 files changed, 18 insertions, 2 deletions

diff --git a/vio/viossl.c b/vio/viossl.c
index 4267486112f..5e4203a3fb5 100644
--- a/vio/viossl.c
+++ b/vio/viossl.c
@@ -140,13 +140,29 @@ int vio_ssl_close(Vio *vio)
                                SSL_get_error(ssl, r)));
       break;
     }
-    SSL_free(ssl);
-    vio->ssl_arg= 0;
   }
   DBUG_RETURN(vio_close(vio));
 }
 
 
+void vio_ssl_delete(Vio *vio)
+{
+  if (!vio)
+    return; /* It must be safe to delete null pointer */
+
+  if (vio->type == VIO_TYPE_SSL)
+    vio_ssl_close(vio); /* Still open, close connection first */
+
+  if (vio->ssl_arg)
+  {
+    SSL_free((SSL*) vio->ssl_arg);
+    vio->ssl_arg= 0;
+  }
+
+  vio_delete(vio);
+}
+
+
 int sslaccept(struct st_VioSSLFd *ptr, Vio *vio, long timeout)
 {
   SSL *ssl;