libcurl from a Windows dll sometimes incorrectly identifies presence of ALPN #7742
Comments
|
I agree we should do something about this. I think libcurl should know the actual version and I don't know what disadvantage there would be to that. |
jay
added a commit
to jay/curl
that referenced
this issue
Oct 4, 2021
- Use RtlVerifyVersionInfo instead of VerifyVersionInfo, when possible. Later versions of Windows have normal version functions that compare and return versions based on the way the application is manifested, instead of the actual version of Windows the application is running on. We prefer the actual version of Windows so we'll now call the Rtl variant of version functions (RtlVerifyVersionInfo) which does a proper comparison of the actual version. Reported-by: Wyatt O'Day Ref: curl#7727 Fixes curl#7742 Closes #xxxx
jay
added a commit
to jay/curl
that referenced
this issue
Oct 4, 2021
- Use RtlVerifyVersionInfo instead of VerifyVersionInfo, when possible. Later versions of Windows have normal version functions that compare and return versions based on the way the application is manifested, instead of the actual version of Windows the application is running on. We prefer the actual version of Windows so we'll now call the Rtl variant of version functions (RtlVerifyVersionInfo) which does a proper comparison of the actual version. Reported-by: Wyatt O'Day Ref: curl#7727 Fixes curl#7742 Closes #xxxx
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
I did this
Compile latest libcurl on Windows with SChannel (either static or dynamic library). Then include either static or dynamic libcurl from inside a dll that will be run in another host application. ALPN detection will now sometimes fail depending on whether the host application was compiled with the correctly configured Application Manifest file.
In this scenario we control the dll (which eventually calls libCurl functionality). However, we do not control the "host application". Meaning the functionality we call in curl could work fine or break depending on whether the host application was compiled and packaged correctly.
Also, this is not a hypothetical situation -- we've seen this in the field.
I expected the following
libCurl should work the same regardless of whether the host application has a manifest configured correctly.
curl/libcurl version
7.79.0
operating system
Windows 8.1 or newer.
Why does it fail?
Incorrect Windows Version detection is used. Or, rather, flaky version detection is used. This was a problem of Microsoft's making (they decided to make some version detection functions flaky).
Solution
Use alternative version detection functions that always returns the correct version. I've already tested and made a PR with the solution. See #7727
The text was updated successfully, but these errors were encountered: