From: "Michał Górny" <mgorny@gentoo.org>
To: gentoo-dev@lists.gentoo.org
Subject: Re: [gentoo-dev] [PATCH v4] kernel-build.eclass: work around permissions issue with module signing
Date: Mon, 11 Dec 2023 12:56:05 +0100 [thread overview]
Message-ID: <ad54f5c0e04169f77d5bfb28dfe91ef171a2bcae.camel@gentoo.org> (raw)
In-Reply-To: <9a4fbdce-29b5-4f82-a200-86a2e0e116f0@gentoo.org>
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On Mon, 2023-12-11 at 12:28 +0100, Andrew Ammerlaan wrote:
> > > diff --git a/eclass/kernel-build.eclass b/eclass/kernel-build.eclass
> > > index f5529c319f9fc..94b499f82fc1e 100644
> > > --- a/eclass/kernel-build.eclass
> > > +++ b/eclass/kernel-build.eclass
> > > @@ -114,6 +114,13 @@ kernel-build_pkg_setup() {
> > > python-any-r1_pkg_setup
> > > if [[ ${KERNEL_IUSE_MODULES_SIGN} ]]; then
> > > secureboot_pkg_setup
> > > + if [[ -e ${MODULES_SIGN_KEY} && ${MODULES_SIGN_KEY} != pkcs11:* ]]; then
> > > + if [[ -e ${MODULES_SIGN_CERT} && ${MODULES_SIGN_CERT} !=
> > > ${MODULES_SIGN_KEY} ]]; then
> > > + MODULES_SIGN_KEY_CONTENTS="$(cat "${MODULES_SIGN_CERT}"
> > > "${MODULES_SIGN_KEY}" || die)"
> >
> > You can use $(<...) builtin instead of calling cat(1).
> >
>
>
> I don't have a strong preference, but I used cat here for esthetic
> symmetry reasons with the line above. Anyway, here's v4:
>
> From 3890c558ff93b9cdb608a3bbcf4c3039f456b571 Mon Sep 17 00:00:00 2001
> From: Violet Purcell <vimproved@inventati.org>
> Date: Mon, 27 Nov 2023 12:12:09 -0500
> Subject: [PATCH] kernel-build.eclass: work around permissions issue with
> module signing
>
> Currently, using a custom path for MODULES_SIGN_KEY requires the key to
> be readable by portage:portage. This is not ideal for security, since
> the file has to be either owned by portage:portage or readable by all
> users in this case. Instead, export the contents of MODULES_SIGN_KEY to
> a variable in pkg_setup, and then create a temporary file with it in
> src_configure to ensure that the temporary key is readable by the user
> that the kernel is being built as. The variable is then unset so it does
> not end up in the final environment file.
>
> Co-authored-by: Andrew Ammerlaan <andrewammerlaan@gentoo.org>
> Signed-off-by: Violet Purcell <vimproved@inventati.org>
> ---
> eclass/kernel-build.eclass | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/eclass/kernel-build.eclass b/eclass/kernel-build.eclass
> index f5529c319f9fc..6b692dc4f9a08 100644
> --- a/eclass/kernel-build.eclass
> +++ b/eclass/kernel-build.eclass
> @@ -114,6 +114,13 @@ kernel-build_pkg_setup() {
> python-any-r1_pkg_setup
> if [[ ${KERNEL_IUSE_MODULES_SIGN} ]]; then
> secureboot_pkg_setup
> + if [[ -e ${MODULES_SIGN_KEY} && ${MODULES_SIGN_KEY} != pkcs11:* ]]; then
> + if [[ -e ${MODULES_SIGN_CERT} && ${MODULES_SIGN_CERT} !=
> ${MODULES_SIGN_KEY} ]]; then
> + MODULES_SIGN_KEY_CONTENTS="$(cat "${MODULES_SIGN_CERT}"
> "${MODULES_SIGN_KEY}" || die)"
> + else
> + MODULES_SIGN_KEY_CONTENTS="$(< "${MODULES_SIGN_KEY}")"
> + fi
> + fi
> fi
> }
>
> @@ -422,12 +429,11 @@ kernel-build_merge_configs() {
> CONFIG_MODULE_SIG_FORCE=y
> CONFIG_MODULE_SIG_${MODULES_SIGN_HASH^^}=y
> EOF
> - if [[ -e ${MODULES_SIGN_KEY} && -e ${MODULES_SIGN_CERT} &&
> - ${MODULES_SIGN_KEY} != ${MODULES_SIGN_CERT} &&
> - ${MODULES_SIGN_KEY} != pkcs11:* ]]
> - then
> - cat "${MODULES_SIGN_CERT}" "${MODULES_SIGN_KEY}" >
> "${T}/kernel_key.pem" || die
> - MODULES_SIGN_KEY="${T}/kernel_key.pem"
> + if [[ -n ${MODULES_SIGN_KEY_CONTENTS} ]]; then
> + (umask 066 && touch "${T}/kernel_key.pem" || die)
> + echo "${MODULES_SIGN_KEY_CONTENTS}" > "${T}/kernel_key.pem" || die
> + unset MODULES_SIGN_KEY_CONTENTS
> + export MODULES_SIGN_KEY="${T}/kernel_key.pem"
> fi
> if [[ ${MODULES_SIGN_KEY} == pkcs11:* || -r ${MODULES_SIGN_KEY} ]];
> then
> echo "CONFIG_MODULE_SIG_KEY=\"${MODULES_SIGN_KEY}\"" \
LGTM but I didn't test it.
--
Best regards,
Michał Górny
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prev parent reply other threads:[~2023-12-11 11:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-27 17:12 [gentoo-dev] [PATCH] kernel-build.eclass: work around permissions issue with module signing Violet Purcell
2023-11-27 17:50 ` Michał Górny
2023-12-11 8:00 ` [gentoo-dev] [PATCH v3] " Andrew Ammerlaan
2023-12-11 11:13 ` Michał Górny
2023-12-11 11:28 ` [gentoo-dev] [PATCH v4] " Andrew Ammerlaan
2023-12-11 11:56 ` Michał Górny [this message]
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