linux-kernel - Re: [PATCH] MODSIGN: Change default key details [ver #2]

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Date:	Thu, 30 Apr 2015 16:39:06 +0200
From:	Sedat Dilek <sedat.dilek@...il.com>
To:	David Howells <dhowells@...hat.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	keyrings@...ux-nfs.org, Rusty Russell <rusty@...tcorp.com.au>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-security-module@...r.kernel.org,
	James Morris <james.l.morris@...cle.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH] MODSIGN: Change default key details [ver #2]

On Thu, Apr 30, 2015 at 3:58 PM, David Howells <dhowells@...hat.com> wrote:
> Change default key details to be more obviously unspecified.
>
> Reported-by: Linus Torvalds <torvalds@...ux-foundation.org>
> Signed-off-by: David Howells <dhowells@...hat.com>
> Acked-by: James Morris <james.l.morris@...cle.com>
> ---
>
>  Documentation/module-signing.txt |    6 +++---
>  kernel/Makefile                  |    6 +++---
>  2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/module-signing.txt b/Documentation/module-signing.txt
> index 09c2382ad055..c72702ec1ded 100644
> --- a/Documentation/module-signing.txt
> +++ b/Documentation/module-signing.txt
> @@ -119,9 +119,9 @@ Most notably, in the x509.genkey file, the req_distinguished_name section
>  should be altered from the default:
>
>         [ req_distinguished_name ]
> -       O = Magrathea
> -       CN = Glacier signing key
> -       emailAddress = slartibartfast@...rathea.h2g2
> +       #O = Unspecified company
> +       CN = Build time autogenerated kernel key
> +       #emailAddress = unspecified.user@...pecified.company
>
>  The generated RSA key size can also be set with:
>
> diff --git a/kernel/Makefile b/kernel/Makefile
> index 0f8f8b0bc1bf..60c302cfb4d3 100644
> --- a/kernel/Makefile
> +++ b/kernel/Makefile
> @@ -197,9 +197,9 @@ x509.genkey:
>         @echo >>x509.genkey "x509_extensions = myexts"
>         @echo >>x509.genkey
>         @echo >>x509.genkey "[ req_distinguished_name ]"
> -       @echo >>x509.genkey "O = Magrathea"
> -       @echo >>x509.genkey "CN = Glacier signing key"
> -       @echo >>x509.genkey "emailAddress = slartibartfast@...rathea.h2g2"
> +       @echo >>x509.genkey "#O = Unspecified company"
> +       @echo >>x509.genkey "CN = Build time autogenerated kernel key"
> +       @echo >>x509.genkey "#emailAddress = unspecified.user@...pecified.company"
>         @echo >>x509.genkey
>         @echo >>x509.genkey "[ myexts ]"
>         @echo >>x509.genkey "basicConstraints=critical,CA:FALSE"
>

[ CC Greg ]

Thanks for considering me.

I reported missing generated files in the "module signature" area.

>From [1]...

[    2.117022] Request for unknown module key 'Magrathea: Glacier
signing key: 009aa341bb673735a51dc34b238a0ca481d68098' err -11
[    2.117114] mii: module verification failed: signature and/or
required key missing - tainting kernel

This happened a 2nd time with a different kernel-series!
Not sure why this was the case.
It did not happen when rebuilding with the same kernel-config again.
Not sure if parallel-make-jobs might be a cause for this (see attached
build-script).

$ egrep -i 'signature|module_sig' /boot/config-4.0.1-1-iniza-small |
grep ^CONFIG
CONFIG_MODULE_SIG=y
CONFIG_MODULE_SIG_ALL=y
CONFIG_MODULE_SIG_SHA512=y
CONFIG_MODULE_SIG_HASH="sha512"
CONFIG_INTEGRITY_SIGNATURE=y
CONFIG_SIGNATURE=y

For my quick builds of rcN Linux-kernels I normally do not need
signing my modules.
I really do not use it (it's taken from the Ubuntu kernel-settings).

Attached is my simple build-script for generating Debian/Ubuntu kernel
packages via builddeb script.

If you have any ideas/hints please let me know.

- Sedat -

[1] https://lkml.org/lkml/2015/2/9/396

Download attachment "config-4.0.1-1-iniza-small" of type "application/octet-stream" (125201 bytes)

Download attachment "build_linux-upstream.sh" of type "application/x-sh" (4504 bytes)