Re: [PATCH v6 0/4] Add support for ECDSA-signed kernel modules

[Jarkko Sakkinen]

On Mon, Jun 14, 2021 at 10:19:51PM +0300, Jarkko Sakkinen wrote:
> On Thu, Jun 10, 2021 at 08:56:19AM -0400, Stefan Berger wrote:
> > This series adds support for ECDSA-signed kernel modules. It also
> > attempts to address a kbuild issue where a developer created an ECDSA
> > key for signing kernel modules and then builds an older version of the
> > kernel, when bisecting the kernel for example, that does not support
> > ECDSA keys.
> > 
> > The first patch addresses the kbuild issue of needing to delete that
> > ECDSA key if it is in certs/signing_key.pem and trigger the creation
> > of an RSA key. However, for this to work this patch would have to be
> > backported to previous versions of the kernel but would also only work
> > for the developer if he/she used a stable version of the kernel to which
> > this patch was applied. So whether this patch actually achieves the
> > wanted effect is not always guaranteed.
> > 
> > The 2nd patch adds the support for the ECSDA-signed kernel modules.
> > 
> > This patch depends on the ECDSA support series currently queued here:
> > https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git/log/?h=ecc
> > 
> >   Stefan
> > 
> > v6:
> >   - Patch 2/4 is fixing V4's 1/2 and 4/4 is fixing V4's 2/2. Both fixup
> >     patches to be squashed.
> > 
> > v5:
> >   - do not touch the key files if openssl is not installed; likely
> >     addresses an issue pointed out by kernel test robot
> > 
> > v4:
> >   - extending 'depends on' with MODULES to (IMA_APPRAISE_MODSIG && MODULES)
> >   
> > v3: - added missing OIDs for ECDSA signed hashes to pkcs7_sig_note_pkey_algo
> >   - added recommendation to use string hash to Kconfig help text
> > 
> > v2:
> >   - Adjustment to ECDSA key detector string in 2/2
> >   - Rephrased cover letter and patch descriptions with Mimi
> > 
> > 
> > Stefan Berger (4):
> >   certs: Trigger creation of RSA module signing key if it's not an RSA
> >     key
> >   certs: Check whether openssl tool is available
> >   certs: Add support for using elliptic curve keys for signing modules
> >   certs: Adjustment due to 'Check whether openssl tool is available'
> > 
> >  certs/Kconfig                         | 26 ++++++++++++++++++++++++++
> >  certs/Makefile                        | 21 +++++++++++++++++++++
> >  crypto/asymmetric_keys/pkcs7_parser.c |  8 ++++++++
> >  3 files changed, 55 insertions(+)
> > 
> > -- 
> > 2.29.2
> > 
> > 
> 
> Since you know the commit ID's in
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd.git
> 
> you could just use fixes-tags and send exactly two patch series. Works
> better with various tools (e.g. https://pypi.org/project/b4/)

And also since then existence of ancestors is guaranteed.

/Jarkko