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From: Georgy Yakovlev <gyakovlev@gentoo.org>
To: gentoo-dev@lists.gentoo.org
Subject: Re: [gentoo-dev] [PATCH] linux-mod.eclass: support module signing
Date: Sun, 26 Jun 2022 03:52:10 -0700	[thread overview]
Message-ID: <84e99a74d64f0d9dd326af0f2c54b9d5717b2f8d.camel@gentoo.org> (raw)
In-Reply-To: <20220621181959.920941-1-concord@gentoo.org>

On Tue, 2022-06-21 at 14:19 -0400, Kenton Groombridge wrote:
> eee74b9fca1 adds support for module compression, but this breaks
> loading
> out of tree modules when module signing is enforced because modules
> must
> be signed before they are compressed. Additionally, the recommended
> Portage hook[1] no longer works with this change.
> 
> Add module signing support in linux-mod.eclass which more or less
> does
> exactly what the aforementioned Portage hook does. If the kernel
> configuration has CONFIG_MODULE_SIG_ALL=y, then read the hash and
> keys
> from the kernel configuration and call the sign_file tool to sign the
> module before it is compressed.
> 
> Bug: https://bugs.gentoo.org/show_bug.cgi?id=447352
> Signed-off-by: Kenton Groombridge <concord@gentoo.org>
> ---
>  eclass/linux-mod.eclass | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/eclass/linux-mod.eclass b/eclass/linux-mod.eclass
> index b7c13cbf7e7..fd40f6d7c6c 100644
> --- a/eclass/linux-mod.eclass
> +++ b/eclass/linux-mod.eclass
> @@ -712,6 +712,22 @@ linux-mod_src_install() {
>                 cd "${objdir}" || die "${objdir} does not exist"
>                 insinto
> "${INSTALL_MOD_PATH}"/lib/modules/${KV_FULL}/${libdir}
>  
> +               # check here for CONFIG_MODULE_SIG_ALL and sign the
> module being built if enabled.
> +               # modules must be signed before they are compressed.
> +
> +               if linux_chkconfig_present MODULE_SIG_ALL; then
> +                       local
> module_sig_hash="$(linux_chkconfig_string MODULE_SIG_HASH)"
> +                       local
> module_sig_key="$(linux_chkconfig_string MODULE_SIG_KEY)"
> +                       module_sig_key="${module_sig_key:-
> certs/signing_key.pem}"
> +                       if [[ "${module_sig_key#pkcs11:}" ==
> "${module_sig_key}" && "${module_sig_key#/}" == "${module_sig_key}"
> ]]; then
> +                               local
> key_path="${KERNEL_DIR}/${module_sig_key}"
> +                       else
> +                               local key_path="${module_sig_key}"
> +                       fi
> +                       local
> cert_path="${KERNEL_DIR}/certs/signing_key.x509"
> +                       "${KERNEL_DIR}"/scripts/sign-file
> ${module_sig_hash//\"} ${key_path//\"} ${cert_path}
> ${modulename}.${KV_OBJ}
> +               fi
> +
>                 # check here for CONFIG_MODULE_COMPRESS_<compression
> option> (NONE, GZIP, XZ, ZSTD) 
>                 # and similarily compress the module being built if
> != NONE.
>  


Hi,

I've spent some time in the past ( circa 2018 ) to get this in, but 
gave up due to various reasons, I was not a gentoo dev yet at the time.

I can't see how posted implementation will work tbh.
portage will strip signature out of the module, unless you prevent
stripping completely or package uses EAPI>=7, and omits stripping
modules via dostrip -x on the ko object.
kernel will NOT load module with stripped signature.

so either you have to sign in pkg_postinst phase, or prevent stripping.
signing in postinst is not ideal, because if breaks recorded file
checksums in vdb.

here's old fork of eclass I made, maybe you can find some helpful code
in there

https://github.com/gyakovlev/linux-mod.eclass/blob/master/linux-mod.eclass

old ML discussion we had:
https://archives.gentoo.org/gentoo-dev/message/4b15b1c851f379a1f802e2f2895cdfa8

You will also need a dependency on openssl, since sign-file uses it.

lmk if you need more info, I might remember more details, but for now
that's all I have. I'll try to help get it done, but my availability is
spotty due to limited time.

  parent reply	other threads:[~2022-06-26 10:52 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-21 18:19 [gentoo-dev] [PATCH] linux-mod.eclass: support module signing Kenton Groombridge
2022-06-21 18:21 ` Kenton Groombridge
2022-06-23 12:51   ` Mike Pagano
2022-06-23 14:30     ` Kenton Groombridge
2022-06-26 10:52 ` Georgy Yakovlev [this message]
2022-06-26 11:15   ` Georgy Yakovlev
2022-06-27 18:35     ` Kenton Groombridge
2022-06-27 18:56       ` Mike Gilbert
2022-06-27 19:18         ` Kenton Groombridge
2022-06-27 19:42         ` Georgy Yakovlev
2022-06-27 19:49           ` Mike Gilbert
2022-06-27 21:11             ` Georgy Yakovlev
2022-06-27 21:50               ` Mike Gilbert
2022-06-27 23:42                 ` Georgy Yakovlev
2022-07-05 19:02                   ` Georgy Yakovlev
2022-07-05 19:55                     ` Kenton Groombridge
2022-07-05 20:11                     ` Mike Gilbert
2022-06-27 19:46       ` Georgy Yakovlev
2022-06-27 20:02         ` Kenton Groombridge
2022-06-27 21:25           ` Georgy Yakovlev
  -- strict thread matches above, loose matches on Subject: below --
2018-04-14 21:25 Georgy Yakovlev
2018-04-15 18:13 ` NP-Hardass

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