[fpc-devel] OpenSSL v1.1.x DLL loading / Bug 37137

[Wayne Sherman]

OpenSSL library loading fixes. Patch file is attached.  Comments are welcome.

Summary:
   1)  For Windows and OS2, remove DLLSSLNameX and DLLUtilNameX
variables.  Instead use matched arrays of DLL filenames (SSL_DLL_Names
and Crypto_DLL_Names)

   2)  Due to refactoring, remove LoadLibHack or LoadLib functions.

   3)  Remove LoadUtilLibrary function, UnloadSSLLib procedure, and
UnloadUtilLib procedure since these were not being called internally
and are unreachable externally.

   4)  Add new function TryLoadLibPair which attempts to load a
matched pair of DLLs (SSL and Crypto).  If either fails to load,
UnloadLibraries is called to clean up.

   5)  Refactored LoadLibraries to use arrays of names for Windows and
OS2, and to use the new TryLoadLibPair helper function for all
platforms.

On Fri, Jun 26, 2020 at 3:36 PM Michael Van Canneyt
<michael at freepascal.org> wrote:
>
>
>
> On Fri, 26 Jun 2020, Wayne Sherman wrote:
>
> > On Thu, Jun 25, 2020 at 11:43 PM Michael Van Canneyt
> > <michael at freepascal.org> wrote:
> >>>
> >>> 3) I recommend the newest libraries be tried first, working backwards
> >>> towards the oldest.
> >>
> >> This is already so ? The version numbers are added from new to old ?
> >
> > The libraries are currently loading in this order:
> >     First attempt:  ssleay32.dll / libeay32.dll (older names, but not oldest)
> >     Second attempt (util):  libcrypto-1_1-x64.dll (newest name)
> >     Third attempt (ssl):  libssl32.dll (oldest name)
> >     Fourth attempt (ssl):  libssl-1_1-x64.dll (newest name)
>
> Oh, you mean the DLL names.
> I thought you meant the version numbers. Yes, this can be changed too.
>
> >>
> >> This needs to be checked.
> >
> > I ran a test.  If a system has a stray file it can cause mismatched
> > DLLs to load (which could result in strange bugs)
> > Please see attached image "OpenSSL_dll_loading_screenshot.png"
>
> We'll adapt the mechanism.
>
> >> I have changed that to 4.0
> >
> > From:  https://www.openssl.org/policies/releasestrat.html
> >    openssl versions 1.1.0, 1.0.2, 1.0.1, 1.0.0 and 0.9.8 are no
> > longer supported
>
> Maybe, but for backwards compatibility they must be supported in FPC.
>
> >
> > So can Windows openssl v1.1 library loading be included in the next
> > maintenance release (v3.2.1?) instead of waiting for v4.0?
>
> No worries, 4.0 means we can consider it for the next fix release.
> That will be 3.2.2 (even numbers only for releases, odd indicates
> development sources)
>
> >
> > Would you like me to have a go at a revised patch?
>
> Sure. If you create a patch, upload it to the bugtracker and assign it to me
> (or mail here so I can have a look)
>
> Michael.
> _______________________________________________
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