Using QSslSocket with custom OpenSSL

[SGaist]

@RMcFatter
Hi and welcome to devnet,

From a quick look at Qt's sources, it doesn't search yet for libcrypto/ssl-1_1.

That something you should check in the bug report system to see if there's already something planned for that.

[Opa114]

same problem here.

I want to use some functions from OpenSSL which i actually can not access from the prebuilt OpenSSL Libs which are shipped with QT (libeay32.dll and ssleay32.dll);

So i thought i can build OpenSSL on my own and link to these libs in my project. This works as expected, but i now have the coexistence of the prebuilt OpenSSL Libs and my own built libs (libcrypto-1_1.dll and libssl-1_1.dll)

This is not a big problem, but i tghought why using these two libs together, when i can maybe use only one? So i tried to rename my own build libs to the names of the old one, but there my application is crashing whith multiple error messages:

qt.network.ssl: QSslSocket: cannot resolve CRYPTO_num_locks
qt.network.ssl: QSslSocket: cannot resolve CRYPTO_set_id_callback
qt.network.ssl: QSslSocket: cannot resolve CRYPTO_set_locking_callback
qt.network.ssl: QSslSocket: cannot resolve ERR_free_strings
qt.network.ssl: QSslSocket: cannot resolve EVP_CIPHER_CTX_cleanup
qt.network.ssl: QSslSocket: cannot resolve EVP_CIPHER_CTX_init
qt.network.ssl: QSslSocket: cannot resolve sk_new_null
qt.network.ssl: QSslSocket: cannot resolve sk_push
qt.network.ssl: QSslSocket: cannot resolve sk_free
qt.network.ssl: QSslSocket: cannot resolve sk_num
qt.network.ssl: QSslSocket: cannot resolve sk_pop_free
qt.network.ssl: QSslSocket: cannot resolve sk_value
qt.network.ssl: QSslSocket: cannot resolve SSL_library_init
qt.network.ssl: QSslSocket: cannot resolve SSL_load_error_strings
qt.network.ssl: QSslSocket: cannot resolve SSL_get_ex_new_index
qt.network.ssl: QSslSocket: cannot resolve SSLv3_client_method
qt.network.ssl: QSslSocket: cannot resolve SSLv23_client_method
qt.network.ssl: QSslSocket: cannot resolve SSLv3_server_method
qt.network.ssl: QSslSocket: cannot resolve SSLv23_server_method
qt.network.ssl: QSslSocket: cannot resolve X509_STORE_CTX_get_chain
qt.network.ssl: QSslSocket: cannot resolve OPENSSL_add_all_algorithms_noconf
qt.network.ssl: QSslSocket: cannot resolve OPENSSL_add_all_algorithms_conf
qt.network.ssl: QSslSocket: cannot resolve SSLeay
qt.network.ssl: QSslSocket: cannot resolve SSLeay_version
qt.network.ssl: QSslSocket: cannot call unresolved function SSLeay
qt.network.ssl: QSslSocket: cannot call unresolved function CRYPTO_num_locks
qt.network.ssl: QSslSocket: cannot call unresolved function CRYPTO_set_id_callback
qt.network.ssl: QSslSocket: cannot call unresolved function CRYPTO_set_locking_callback
qt.network.ssl: QSslSocket: cannot call unresolved function SSL_library_init
qt.network.ssl: QSslSocket: cannot call unresolved function SSLv23_client_method
qt.network.ssl: QSslSocket: cannot call unresolved function sk_num

Then i found this Thread here and hoped to get the solution, but no, like @SGaist said. So i think i have to wait for an updated Qt version so that i can replace the files. Or could it be the better solution to built Qt on my own with own OpenSSL Support? if yes, is there a good Tutorial? Or can i use ALL the OpenSSL Functions with the prebuilt OpenSSL in Qt? If yes, a little example would be nice, because i don't got it.

[SGaist]

You can build Qt with the -openssl-linked option and point configure to your self-built version of OpenSSL.

[Opa114]

@SGaist said in Using QSslSocket with custom OpenSSL:

You can build Qt with the -openssl-linked option and point configure to your self-built version of OpenSSL.

i tried it that way, but buildung QT 5.7 with OpenSSL 1.1.0b ist not supported till QT 5.9 because in OpenSSL are some changes done, so that building QT 5.7 with that new OpenSSL version did not work. See here: https://bugreports.qt.io/browse/QTBUG-52905

Then i tried it with an older version of OpenSSL (1.0.2j) - this works.

But what ist the difference between building Qt gainst OpenSSL with -openssl on running the configure-command and to link against the OpenSSL headers and libs and build it inside the Project? If i build against OpenSSL i have to include the headers anyway to work with the libs if i want to use the OpenSSL specific stuff.

And i noticed that i can replace the built in OpenSSL libs with the own build one. So it would be much simpler to include the ehaders of OpenSSL via INCLUDEPATH. So i get OpenSSL support = true on output of: qDebug() << QSslSocket::supportsSsl();

And if print out his i got the Output which i wrote behind:
qDebug() << QSslSocket::sslLibraryBuildVersionString(); // OpenSSL 1.0.2g 1 Mar 2016
qDebug() << QSslSocket::sslLibraryVersionString(); // OpenSSL 1.0.2j 26 Sep 2016

Why is the first one at all time: OpenSSL 1.0.2g 1 Mar 2016 - This i got, too if i build Qt at own and link against OpenSSL 1.0.2j??

[SGaist]

It's in the docs:
sslLibraryBuildVersionString is returning the version of the OpenSSL library used when building Qt.
sslLibraryVersionString is returning the version of the OpenSSL library used at run time.

By default OpenSSL is dlopened because some countries have restrictions about encryption related software and OpenSSL can't be distributed just like that.

[Opa114]

Thanks! But why are my versions different?
I build Qt with OpenSSL 1.0.2j, so both outputs must be the same or not?

[SGaist]

Silly question but are you sure that you are using your self-build Qt in your kit ?

[Opa114]

@SGaist said in Using QSslSocket with custom OpenSSL:

Silly question but are you sure that you are using your self-build Qt in your kit ?

yes :)
could it have to do with Qt-Creator, which was build with another version?

[SGaist]

No, the Qt version used to build Qt Creator doesn't affect any any way the Qt version you are using with your kit.

Do you have another OpenSSL version installed on your system ?

[Opa114]

@SGaist said in Using QSslSocket with custom OpenSSL:

on used to bui

no not installed like the precompiled OpenSSL Libraries. I searched the whole PC (Windows) for OpenSSL and libeay32.dll. I found many applications which are using OpenSSL but only one Application uses the specific OpenSSL version OpenSSL 1.0.2g 1 Mar 2016 i posted above. This Application is Adobe Lightroom.

Could this be the problem on building Qt that some shipped libeay32.dlls are used on build process?

[CarlosQ]

@SGaist Sorry, i have the same problem.
When i print:
qDebug() << QSslSocket::supportsSsl(); ==> false
qDebug() << QSslSocket::sslLibraryBuildVersionString(); ==> "OpenSSL 1.0.2g 1 Mar 2016"
qDebug() << QSslSocket::sslLibraryVersionString(); ==> ""

and i obtain these messages:
qt.network.ssl: QSslSocket: cannot call unresolved function SSLv23_client_method
qt.network.ssl: QSslSocket: cannot call unresolved function SSL_CTX_new
qt.network.ssl: QSslSocket: cannot call unresolved function SSL_library_init
qt.network.ssl: QSslSocket: cannot call unresolved function ERR_get_error
qt.network.ssl: QSslSocket: cannot call unresolved function ERR_get_error

I have instaled only Qt 5.7 on Windows 7 32. What can i do?
Thanks

[SGaist]

Hi,

Do you have OpenSSL installed ? Built with the same compiler as Qt ? In a folder known to your application ?

[CarlosQ]

@SGaist No, no and no. Ohhhh. i'll try to build the libraries.

Sorry, thanks.

[SGaist]

You can find here prebuilt versions of OpenSSL for various compilers.

[CarlosQ]

@SGaist Thank you for the link. I was trying to build the libraries and I'm going crazy.

I have Qt 5.7.0 on a Windows 7 32 bits, which instalation should be correct?. I think "Win32 OpenSSL v1.1.0c". Is it ok?.

Thanks again.

[SGaist]

IIRC there was a renaming of the libraries of OpenSSL so you'll have to double check.