linux-integrity.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Sumit Garg <sumit.garg@linaro.org>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: Andreas Rammhold <andreas@rammhold.de>,
	James Bottomley <jejb@linux.ibm.com>,
	Jarkko Sakkinen <jarkko@kernel.org>,
	Mimi Zohar <zohar@linux.ibm.com>,
	David Howells <dhowells@redhat.com>,
	James Morris <jmorris@namei.org>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	linux-integrity <linux-integrity@vger.kernel.org>,
	"open list:ASYMMETRIC KEYS" <keyrings@vger.kernel.org>,
	"open list:SECURITY SUBSYSTEM" 
	<linux-security-module@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Pengutronix Kernel Team <kernel@pengutronix.de>
Subject: Re: [PATCH] KEYS: trusted: Fix trusted key backends when building as module
Date: Mon, 19 Jul 2021 13:36:09 +0530	[thread overview]
Message-ID: <CAFA6WYNC2xasX4uKmgcK+ZmA4HUh5PhCci+e12VFWPfF0b0eWQ@mail.gmail.com> (raw)
In-Reply-To: <0a684d56-66d0-184e-4853-9faafa2d243d@pengutronix.de>

On Mon, 19 Jul 2021 at 12:40, Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
>
> Hello Andreas,
>
> On 16.07.21 10:17, Andreas Rammhold wrote:
> > Before this commit the kernel could end up with no trusted key sources
> > even thought both of the currently supported backends (tpm & tee) were
> > compoiled as modules. This manifested in the trusted key type not being
> > registered at all.
>
> I assume (TPM) trusted key module use worked before the TEE rework? If so,
>
> an appropriate Fixes: Tag would then be in order.
>
> > When checking if a CONFIG_… preprocessor variable is defined we only
> > test for the builtin (=y) case and not the module (=m) case. By using
> > the IS_ENABLE(…) macro we to test for both cases.
>
> It looks to me like you could now provoke a link error if TEE is a module
> and built-in trusted key core tries to link against trusted_key_tee_ops.
>

That's true.

> One solution for that IS_REACHABLE(). Another is to address the root cause,
> which is the inflexible trusted keys Kconfig description:
>
> - Trusted keys despite TEE support can still only be built when TCG_TPM is enabled
> - There is no support to have TEE or TPM enabled without using those for
>   enabled trusted keys as well
> - As you noticed, module build of the backend has issues
>
> I addressed these three issues in a patch[1], a month ago, but have yet to
> receive feedback.

That's an oversight on my part since this patch was part of the new
CAAM trust source patch-set. Although I do admit that it was on my
TODO list. So I have provided some feedback on that patch. Can you
post the next version as an independent fix patch?

-Sumit

>
> [1]: https://lore.kernel.org/linux-integrity/f8285eb0135ba30c9d846cf9dd395d1f5f8b1efc.1624364386.git-series.a.fatoum@pengutronix.de/
>
> Cheers,
> Ahmad
>
> > Signed-off-by: Andreas Rammhold <andreas@rammhold.de>
> > ---
> >  security/keys/trusted-keys/trusted_core.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c
> > index d5c891d8d353..fd640614b168 100644
> > --- a/security/keys/trusted-keys/trusted_core.c
> > +++ b/security/keys/trusted-keys/trusted_core.c
> > @@ -27,10 +27,10 @@ module_param_named(source, trusted_key_source, charp, 0);
> >  MODULE_PARM_DESC(source, "Select trusted keys source (tpm or tee)");
> >
> >  static const struct trusted_key_source trusted_key_sources[] = {
> > -#if defined(CONFIG_TCG_TPM)
> > +#if IS_ENABLED(CONFIG_TCG_TPM)
> >       { "tpm", &trusted_key_tpm_ops },
> >  #endif
> > -#if defined(CONFIG_TEE)
> > +#if IS_ENABLED(CONFIG_TEE)
> >       { "tee", &trusted_key_tee_ops },
> >  #endif
> >  };
> >
>
>
> --
> Pengutronix e.K.                           |                             |
> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

  reply	other threads:[~2021-07-19  8:06 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-16  8:17 Andreas Rammhold
2021-07-19  6:26 ` Sumit Garg
2021-07-19  7:10 ` Ahmad Fatoum
2021-07-19  8:06   ` Sumit Garg [this message]
2021-07-19  9:13     ` andreas
2021-07-27  2:57   ` Jarkko Sakkinen
2021-07-27  2:55 ` Jarkko Sakkinen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAFA6WYNC2xasX4uKmgcK+ZmA4HUh5PhCci+e12VFWPfF0b0eWQ@mail.gmail.com \
    --to=sumit.garg@linaro.org \
    --cc=a.fatoum@pengutronix.de \
    --cc=andreas@rammhold.de \
    --cc=dhowells@redhat.com \
    --cc=jarkko@kernel.org \
    --cc=jejb@linux.ibm.com \
    --cc=jmorris@namei.org \
    --cc=kernel@pengutronix.de \
    --cc=keyrings@vger.kernel.org \
    --cc=linux-integrity@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=serge@hallyn.com \
    --cc=zohar@linux.ibm.com \
    --subject='Re: [PATCH] KEYS: trusted: Fix trusted key backends when building as module' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).