Re: [PATCH v2] module: sign with sha512 instead of sha1 by default

[Luis Chamberlain]

On Wed, Oct 16, 2024 at 04:18:41PM +0200, Thorsten Leemhuis wrote:
> Switch away from using sha1 for module signing by default and use the
> more modern sha512 instead, which is what among others Arch, Fedora,
> RHEL, and Ubuntu are currently using for their kernels.
> 
> Sha1 has not been considered secure against well-funded opponents since
> 2005[1]; since 2011 the NIST and other organizations furthermore
> recommended its replacement[2]. This is why OpenSSL on RHEL9, Fedora
> Linux 41+[3], and likely some other current and future distributions
> reject the creation of sha1 signatures, which leads to a build error of
> allmodconfig configurations:
> 
>   80A20474797F0000:error:03000098:digital envelope routines:do_sigver_init:invalid digest:crypto/evp/m_sigver.c:342:
>   make[4]: *** [.../certs/Makefile:53: certs/signing_key.pem] Error 1
>   make[4]: *** Deleting file 'certs/signing_key.pem'
>   make[4]: *** Waiting for unfinished jobs....
>   make[3]: *** [.../scripts/Makefile.build:478: certs] Error 2
>   make[2]: *** [.../Makefile:1936: .] Error 2
>   make[1]: *** [.../Makefile:224: __sub-make] Error 2
>   make[1]: Leaving directory '...'
>   make: *** [Makefile:224: __sub-make] Error 2
> 
> This change makes allmodconfig work again and sets a default that is
> more appropriate for current and future users, too.
> 
> Link: https://www.schneier.com/blog/archives/2005/02/cryptanalysis_o.html [1]
> Link: https://csrc.nist.gov/projects/hash-functions [2]
> Link: https://fedoraproject.org/wiki/Changes/OpenSSLDistrustsha1SigVer [3]
> Signed-off-by: Thorsten Leemhuis <linux@xxxxxxxxxxxxx>

Thanks!

Tested-by: kdevops <kdevops@xxxxxxxxxxxxxxx> [0]
Links: https://github.com/linux-kdevops/linux-modules-kpd/actions/runs/11420092929/job/31775404330 # [0]

Applied and pushed!

  Luis