Order of Cleanup to avoid memory leaks?

[Jeffrey Walton]

I'm trying to remediate a couple of memory leaks on shutdown. I'm
having trouble: (1) locating a definitive guide that lists what should
be called during cleanup; and (2) what order they should be called in.

The closest I've find to answering the questions are (1) OpenSSL
source code; and (2)
http://marc.info/?l=openssl-dev&m=104999183723322&w=2. OpenSSL source
code is a bit confusing because the various programs and demos mostly
do things differently. The openssl-dev posting is good, but I've still
got some leaks.

I start the application with:

CRYPTO_malloc_debug_init();
CRYPTO_mem_ctrl(CRYPTO_MEM_CHECK_ON);

SSL_library_init();
SSL_load_error_strings();
FIPS_mode_set(1);
// Install static locks
// Create Client Context
// Create Server Context
// Load DH params

I shutdown the application with the following (in this order):

FIPS_mode_set(0);
// Remove static locks
// Destroy Client Context
// Destroy Server Context
// Unload DH params
ENGINE_cleanup();
CONF_modules_unload(1);
EVP_cleanup();
CRYPTO_cleanup_all_ex_data();
ERR_remove_state(0);
ERR_free_strings();

Then I dump state:

CRYPTO_mem_leaks_fp(stderr);

This results in the following (in addition to a Valgrind complaint):

Debug: dumping OpenSSL memory state
4206 file=err.c, line=1019, number=600, address=065CFDC0
4120 file=lhash.c, line=119, number=176, address=065BEFA0
> thread=67351016, file=err.c, line=449, info="int_thread_get (err.c)"
4207 file=lhash.c, line=193, number=24, address=065D0150
4121 file=lhash.c, line=121, number=128, address=065BF180
> thread=67351016, file=err.c, line=449, info="int_thread_get (err.c)"
928 bytes leaked in 4 chunks

What order are these functions supposed to be called in to cleanup the
leak in "err.c"?

Thanks in advance
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[Jeffrey Walton]

Here's the code that's causing the leak. It only happens on a non-existent file.

BIO bio = BIO_new_file("does-not-exist", "r");
// dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);

I still don't know how to clear it, however.

Is there some *_cleanup() I missed? Does order matter?

Jeff

[Dr. Stephen Henson]

That looks like a per-thread error queue has been allocated and not freed up.
Does the application use threads? If so you need to call ERR_remove_state
in each thread before it exits.

Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org