[openssl/openssl] d840f0: Avoid crashing if CONF_modules_unload() is called ...

[Tomas Mraz]

  Branch: refs/heads/master
  Home:   https://github.openssl.org/openssl/openssl
  Commit: d840f07bcdfc3910de5aa327a245866a67f94799
      https://github.openssl.org/openssl/openssl/commit/d840f07bcdfc3910de5aa327a245866a67f94799
  Author: Tomas Mraz <tomas at openssl.org>
  Date:   2022-07-01 (Fri, 01 Jul 2022)

  Changed paths:
    M crypto/conf/conf_mod.c

  Log Message:
  -----------
  Avoid crashing if CONF_modules_unload() is called after OPENSSL_cleanup()

Although this is basically an incorrect API call it was not crashing
before and it might happen inadvertently if CONF_modules_unload()
is called from a destructor for example.

Fixes #18669

Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Hugo Landau <hlandau at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18673)