diff mbox series

builddeb: Support signing kernels with a Machine Owner Key

Message ID 20210506115813.397657-1-willy@infradead.org (mailing list archive)
State New
Headers show
Series builddeb: Support signing kernels with a Machine Owner Key | expand

Commit Message

Matthew Wilcox May 6, 2021, 11:58 a.m. UTC
If the config file specifies a signing key, use it to sign
the kernel so that machines with SecureBoot enabled can boot.
See https://wiki.debian.org/SecureBoot

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 scripts/package/builddeb | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

Comments

Ard Biesheuvel May 6, 2021, 12:01 p.m. UTC | #1
On Thu, 6 May 2021 at 14:00, Matthew Wilcox (Oracle)
<willy@infradead.org> wrote:
>
> If the config file specifies a signing key, use it to sign
> the kernel so that machines with SecureBoot enabled can boot.
> See https://wiki.debian.org/SecureBoot
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  scripts/package/builddeb | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/package/builddeb b/scripts/package/builddeb
> index 91a502bb97e8..4fa6ff2b5cac 100755
> --- a/scripts/package/builddeb
> +++ b/scripts/package/builddeb
> @@ -147,7 +147,15 @@ else
>         cp System.map "$tmpdir/boot/System.map-$version"
>         cp $KCONFIG_CONFIG "$tmpdir/boot/config-$version"
>  fi
> -cp "$($MAKE -s -f $srctree/Makefile image_name)" "$tmpdir/$installed_image_path"
> +
> +vmlinux=$($MAKE -s -f $srctree/Makefile image_name)
> +if is_enabled CONFIG_MODULE_SIG; then

Shouldn't this be conditional on CONFIG_EFI as well?

> +       cert=$srctree/$(grep ^CONFIG_MODULE_SIG_KEY= include/config/auto.conf | cut -d\" -f2)
> +       key=${cert%pem}priv
> +       sbsign --key $key --cert $cert "$vmlinux" --output "$tmpdir/$installed_image_path"
> +else
> +       cp "$vmlinux" "$tmpdir/$installed_image_path"
> +fi
>
>  if is_enabled CONFIG_OF_EARLY_FLATTREE; then
>         # Only some architectures with OF support have this target
> --
> 2.30.2
>
Matthew Wilcox May 6, 2021, 1:36 p.m. UTC | #2
On Thu, May 06, 2021 at 02:01:53PM +0200, Ard Biesheuvel wrote:
> On Thu, 6 May 2021 at 14:00, Matthew Wilcox (Oracle)
> <willy@infradead.org> wrote:
> >
> > If the config file specifies a signing key, use it to sign
> > the kernel so that machines with SecureBoot enabled can boot.
> > See https://wiki.debian.org/SecureBoot
> >
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > ---
> >  scripts/package/builddeb | 10 +++++++++-
> >  1 file changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/scripts/package/builddeb b/scripts/package/builddeb
> > index 91a502bb97e8..4fa6ff2b5cac 100755
> > --- a/scripts/package/builddeb
> > +++ b/scripts/package/builddeb
> > @@ -147,7 +147,15 @@ else
> >         cp System.map "$tmpdir/boot/System.map-$version"
> >         cp $KCONFIG_CONFIG "$tmpdir/boot/config-$version"
> >  fi
> > -cp "$($MAKE -s -f $srctree/Makefile image_name)" "$tmpdir/$installed_image_path"
> > +
> > +vmlinux=$($MAKE -s -f $srctree/Makefile image_name)
> > +if is_enabled CONFIG_MODULE_SIG; then
> 
> Shouldn't this be conditional on CONFIG_EFI as well?

Maybe!  We're a long way outside my area of expertise.  I'm just chuffed
I thought of using cut -d\" -f2.

There should probably also be something conditional on sbsign actually
being in $PATH, I guess?

And I wasn't sure about putting all of this in builddeb -- does make
rpm-pkg already have its own way of doing the same thing, or should this
be somewhere more generic?

> > +       cert=$srctree/$(grep ^CONFIG_MODULE_SIG_KEY= include/config/auto.conf | cut -d\" -f2)
> > +       key=${cert%pem}priv
> > +       sbsign --key $key --cert $cert "$vmlinux" --output "$tmpdir/$installed_image_path"
> > +else
> > +       cp "$vmlinux" "$tmpdir/$installed_image_path"
> > +fi
> >
> >  if is_enabled CONFIG_OF_EARLY_FLATTREE; then
> >         # Only some architectures with OF support have this target
> > --
> > 2.30.2
> >
Ard Biesheuvel May 6, 2021, 5:38 p.m. UTC | #3
(+ Peter)

On Thu, 6 May 2021 at 15:37, Matthew Wilcox <willy@infradead.org> wrote:
>
> On Thu, May 06, 2021 at 02:01:53PM +0200, Ard Biesheuvel wrote:
> > On Thu, 6 May 2021 at 14:00, Matthew Wilcox (Oracle)
> > <willy@infradead.org> wrote:
> > >
> > > If the config file specifies a signing key, use it to sign
> > > the kernel so that machines with SecureBoot enabled can boot.
> > > See https://wiki.debian.org/SecureBoot
> > >
> > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > > ---
> > >  scripts/package/builddeb | 10 +++++++++-
> > >  1 file changed, 9 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/scripts/package/builddeb b/scripts/package/builddeb
> > > index 91a502bb97e8..4fa6ff2b5cac 100755
> > > --- a/scripts/package/builddeb
> > > +++ b/scripts/package/builddeb
> > > @@ -147,7 +147,15 @@ else
> > >         cp System.map "$tmpdir/boot/System.map-$version"
> > >         cp $KCONFIG_CONFIG "$tmpdir/boot/config-$version"
> > >  fi
> > > -cp "$($MAKE -s -f $srctree/Makefile image_name)" "$tmpdir/$installed_image_path"
> > > +
> > > +vmlinux=$($MAKE -s -f $srctree/Makefile image_name)
> > > +if is_enabled CONFIG_MODULE_SIG; then
> >
> > Shouldn't this be conditional on CONFIG_EFI as well?
>
> Maybe!  We're a long way outside my area of expertise.  I'm just chuffed
> I thought of using cut -d\" -f2.
>
> There should probably also be something conditional on sbsign actually
> being in $PATH, I guess?
>
> And I wasn't sure about putting all of this in builddeb -- does make
> rpm-pkg already have its own way of doing the same thing, or should this
> be somewhere more generic?
>

No, sbsign is Debian/Ubuntu specific. Fedora/Redhat uses something
else IIRC. But yes, it obviously helps if the tool exists.


> > > +       cert=$srctree/$(grep ^CONFIG_MODULE_SIG_KEY= include/config/auto.conf | cut -d\" -f2)
> > > +       key=${cert%pem}priv
> > > +       sbsign --key $key --cert $cert "$vmlinux" --output "$tmpdir/$installed_image_path"
> > > +else
> > > +       cp "$vmlinux" "$tmpdir/$installed_image_path"
> > > +fi
> > >
> > >  if is_enabled CONFIG_OF_EARLY_FLATTREE; then
> > >         # Only some architectures with OF support have this target
> > > --
> > > 2.30.2
> > >
diff mbox series

Patch

diff --git a/scripts/package/builddeb b/scripts/package/builddeb
index 91a502bb97e8..4fa6ff2b5cac 100755
--- a/scripts/package/builddeb
+++ b/scripts/package/builddeb
@@ -147,7 +147,15 @@  else
 	cp System.map "$tmpdir/boot/System.map-$version"
 	cp $KCONFIG_CONFIG "$tmpdir/boot/config-$version"
 fi
-cp "$($MAKE -s -f $srctree/Makefile image_name)" "$tmpdir/$installed_image_path"
+
+vmlinux=$($MAKE -s -f $srctree/Makefile image_name)
+if is_enabled CONFIG_MODULE_SIG; then
+	cert=$srctree/$(grep ^CONFIG_MODULE_SIG_KEY= include/config/auto.conf | cut -d\" -f2)
+	key=${cert%pem}priv
+	sbsign --key $key --cert $cert "$vmlinux" --output "$tmpdir/$installed_image_path"
+else
+	cp "$vmlinux" "$tmpdir/$installed_image_path"
+fi
 
 if is_enabled CONFIG_OF_EARLY_FLATTREE; then
 	# Only some architectures with OF support have this target