Signing cygwin.com binaries with signtool by default ?

[Brian Inglis]

On 2025-05-03 12:21, Roland Mainz via Cygwin wrote:
> Is it somehow possible that the CI+Release binaries (*.exe, *.dll) can
> be signed with signtool
> (https://learn.microsoft.com/en-us/windows/win32/seccrypto/signtool)?

No - would break the Cygwin licence terms unless MS releases source!

> It seems that Microsoft Defender has become overly aggressive to some
> Cygwin binaries (mostly /usr/bin/hostname, /usr/bin/find, /usr/bin/tar
> etc.) in the last couple of weeks and just blocks them.

Aha - more MS Embrace, Extend, Extinguish!

Which Windows, Defender, and Cygwin releases did this start with?

$ which -a find hostname tar | cyg-sanitize-output.sed
/usr/bin/find
/proc/cygdrive/c/WINDOWS/system32/find
/usr/bin/hostname
/proc/cygdrive/c/WINDOWS/system32/hostname
/usr/bin/tar
/proc/cygdrive/c/WINDOWS/system32/tar

Perhaps Cygwin installer or cygcheck should start renaming MS Windows binaries 
whose names conflict with Cygwin utilities! ;^>

What about other packages that install exes whose names conflict with MS Windows 
utilities - does MS block them also, or just Cygwin's, or also other open 
source; what about WSL installs?

[I noticed today that MS supports using only its own proprietary FIDO passkey 
authenticator app - which nobody sensible would ever trust! I liked when we used 
to be able to delete MS crypto keys from the MS Windows keystore.]

> Our IT supports that they can "whitelist" binaries based on their
> cryptographic signature... but neither the binaries from the CI nor
> the Release binaries have any signatures...

Perhaps your paid IT support could just figure out how they could bypass 
Defender checking the Cygwin roots or /*bin/ dirs?

I suspect many of us do that to reduce the overhead of the BLODA.

Or perhaps your paid IT support could just figure out how they could provide 
their own Cygwin mirror with binaries signed with their own signatures and tools.

Cygwin supports osslsigncode:

	https://cygwin.com/packages/summary/osslsigncode-src.html

OpenSSL-based Authenticode signing and timestamping tool

Platform-independent tool for Authenticode signing of PE(EXE/SYS/DLL/etc), CAB 
and MSI files. It also supports timestamping (Authenticode and RFC3161).

That would require our volunteers to find and spend more of their free time to 
integrate the tool into the package build processes, and it would not be 
available until the volunteers find more of their free time once the next 
release of each upstream package becomes available.

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retrancher  but when there is no more to cut
                                 -- Antoine de Saint-Exupéry