segfault in EVP_DigestInit_ex (lws_tls_client_create_vhost_context)

[chenuduss]

My application use fork(). Also my app multiple times open and closes websocket objects (open threated as lws_create_context+lws_ss_create).

On version 4.5.8, when reopening a websocket object after fork(), segfault occurs in the lws_tls_client_create_vhost_context function on the line:

if (EVP_DigestInit_ex(mdctx, EVP_sha256(), NULL) != 1) {

There were no problems on versions 4.5.1 and 4.5.2.

[lws-team]

This is likely due to the cursed OpenSSL cleanup stuff.

On main, it's removed by d1c1276 you might see if backporting that solves it.

[chenuduss]

There's also the following problem in 4.5.8: if my application already uses OPENSSL, other application components may crash.

if I create and then destroy a websocket object, then in version 4.5.8, when calling lws_context_destroy, lws_context_deinit_ssl_library() is called, which leads to a call OPENSSL_cleanup(), since I only had one object, and the openssl_contexts_using_global_init counter will be reset. Unnecessary call OPENSSL_cleanup will lead to incorrect operation of other application components that use OPENSSL.

[lws-team]

With the patch I pointed to, it should be opt-in whether you want to call the clean-up thing from then on. This patch is on main for a while.