Am 22.07.24 um 00:15 schrieb Hendrik Leppkes:
On Mon, Jul 22, 2024 at 12:08 AM Stefan Oltmanns via ffmpeg-devel
<ffmpeg-devel@ffmpeg.org> wrote:

Am 18.07.24 um 17:23 schrieb epira...@gmail.com:


Well, the DLL directory is added to PATH by the VapourSynth installer,
but for safety reasons ffmpeg explictly tells the LoadLibrary function
to only search the application directory and system32, quote from
w32dlfcn.h:

/**
   * Safe function used to open dynamic libs. This attempts to improve program 
security
   * by removing the current directory from the dll search path. Only dll's 
found in the
   * executable or system directory are allowed to be loaded.
   * @param name  The dynamic lib name.
   * @return A handle to the opened lib.
   */
So ffmpeg prevents that solution on purpose. Or should that behavior be
changed in the w32dlfcn.h?

Oh, bummer. I would expect that overriding the PATH environment
variable would work kind of like how LD_LIBRARY_PATH works on Linux. I
don't know why that was changed. I don't really follow what goes on in
Windowsland anymore. Does anyone else care to comment on this? Martin,
maybe?

IIRC this is done to prevent DLL injection attacks

https://learn.microsoft.com/en-us/windows/win32/dlls/dynamic-link-library-security


So what's your proposal how to continue?

I see different options with pros&cons:


1.
Read the DLL path from registry, function for that could be located
outside the VapourSynth module.

Pro: Safest method to protect from DLL-injection
Con: A lot of custom code/functionality for Windows


Relaxing security considerations to avoid a 10 line function seems not
worth it to me. So go with actually finding the correct path.


Ok, should that function remain in the vapoursynth module, or should
handling the registry be done in a header like "compat/w32registry.h"?

An external file with a universal function would of course require more
code.


Best regards
Stefan

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".

Reply via email to