Issue 28588: Memory leak in OpenSSL thread state (original) (raw)

Issue28588

Created on 2016-11-02 12:01 by christian.heimes, last changed 2022-04-11 14:58 by admin. This issue is now closed.

Messages (2)
msg279922 - (view)	Author: Christian Heimes (christian.heimes) *	Date: 2016-11-02 12:01
Quote from https://github.com/curl/curl/issues/964 --- I wrote to Matt Caswell from openssl.org about this memleah, and he answered: OpenSSL maintains a separate error queue for each thread. On each queue there can be multiple errors. ERR_get_state() does not add any errors to the queue it merely returns the ERR_STATE (i.e. the queue) for the current thread. If the current thread has no queue then ERR_get_state() will create one. ERR_clear_error() removes all the errors that are on the current thread's queue. It does not deallocate the current thread's queue. ERR_remove_thread_state() deallocates the specified thread's queue. The mem leaks you are seeing are almost certainly because the queues for your app's threads have not been deallocated. --- The memory leak only affects OpenSSL 1.0.2 and older. OpenSSL 1.1.0 takes care of threading, locking and thread local resources itself.
msg301626 - (view)	Author: Christian Heimes (christian.heimes) *	Date: 2017-09-07 20:39
It's rather painful to fix the issue. Since the memory leak only affects users that create and destroy a lot of threads and the bug has been addressed by OpenSSL 1.1.0, I won't fix it. If users are running into the issue, they should rather update to more recent OpenSSL versions. The 1.1.0 series uses proper thread local storage.