From: Rusty Russell <rusty@ozlabs.org>
To: David Howells <dhowells@redhat.com>, keyrings@linux-nfs.org
Cc: linux-crypto@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, dmitry.kasatkin@intel.com,
zohar@linux.vnet.ibm.com, arjan.van.de.ven@intel.com,
alan.cox@intel.com, David Howells <dhowells@redhat.com>
Subject: Re: [PATCH 21/21] MODSIGN: Apply signature checking to modules on module load [ver #3]
Date: Fri, 09 Dec 2011 21:48:45 +1030 [thread overview]
Message-ID: <87boriouwa.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20111202184651.21874.57769.stgit@warthog.procyon.org.uk>
On Fri, 02 Dec 2011 18:46:51 +0000, David Howells <dhowells@redhat.com> wrote:
> Signed modules may be safely stripped as the signature only covers those parts
> of the module the kernel actually uses and any ELF metadata required to deal
> with them. Any necessary ELF metadata that is affected by stripping is
> canonicalised by the sig generator and the sig checker to hide strip effects.
>
> This permits the debuginfo to be detached from the module and placed
> in another spot so that gdb can find it when referring to that module
> without the need for multiple signed versions of the module. Such is
> done by rpmbuild when producing RPMs.
>
> It also permits the module to be stripped as far as possible for when modules
> are being reduced prior to being included in an initial ramdisk composition.
And adds a great deal of code in a supposedly security-sensitive path to
achieve it.
How about simply append a signature to the module? That'd be about 20
lines of code to carefully check the bounds of the module to figure out
where the signature is. You could even allow multiple signatures, then
have one for stripped, and one for non-stripped versions.
Sure, you now need to re-append that after stripping, but that's not the
kernel's problem.
Cheers,
Rusty.
PS. Yay for finding out about module patches via LWN! How would you
get this in without my ack, FFS?
next prev parent reply other threads:[~2011-12-09 12:06 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-02 18:42 [RFC][PATCH 00/21] Crypto keys and module signing [ver #3] David Howells
2011-12-02 18:42 ` [PATCH 01/21] MPILIB: Export some more symbols " David Howells
2011-12-02 18:42 ` [PATCH 02/21] MPILIB: Add a missing ENOMEM check " David Howells
2011-12-02 18:43 ` [PATCH 03/21] KEYS: Permit key_serial() to be called with a const key pointer " David Howells
2011-12-02 18:43 ` [PATCH 04/21] KEYS: Move the key config into security/keys/Kconfig " David Howells
2011-12-02 18:43 ` [PATCH 05/21] KEYS: Announce key type (un)registration " David Howells
2011-12-02 18:43 ` [PATCH 06/21] KEYS: Reorganise keys Makefile " David Howells
2011-12-02 18:43 ` [PATCH 07/21] KEYS: Create a key type that can be used for general cryptographic operations " David Howells
2012-01-16 12:53 ` Mimi Zohar
2012-01-17 15:32 ` David Howells
2012-01-18 10:56 ` Kasatkin, Dmitry
2011-12-02 18:44 ` [PATCH 08/21] KEYS: Add signature verification facility " David Howells
2012-01-18 11:20 ` Kasatkin, Dmitry
2012-01-18 12:26 ` David Howells
2012-01-18 13:26 ` Kasatkin, Dmitry
2012-01-18 15:13 ` David Howells
2012-01-18 15:20 ` Kasatkin, Dmitry
2012-01-18 19:59 ` David Howells
2012-01-20 1:52 ` Herbert Xu
2011-12-02 18:44 ` [PATCH 09/21] KEYS: Asymmetric public-key algorithm crypto key subtype " David Howells
2011-12-02 18:44 ` [PATCH 10/21] KEYS: DSA signature verification algorithm " David Howells
2011-12-02 18:44 ` [PATCH 11/21] KEYS: RSA " David Howells
2011-12-02 18:44 ` [PATCH 12/21] PGPLIB: PGP definitions (RFC 4880) " David Howells
2011-12-02 18:45 ` [PATCH 13/21] PGPLIB: Basic packet parser " David Howells
2011-12-02 18:45 ` [PATCH 14/21] PGPLIB: Signature " David Howells
2011-12-02 18:45 ` [PATCH 15/21] KEYS: PGP data " David Howells
2011-12-02 18:45 ` [PATCH 16/21] KEYS: PGP-based public key signature verification " David Howells
2012-01-18 11:36 ` Kasatkin, Dmitry
2012-01-18 12:49 ` David Howells
2012-01-18 13:34 ` Kasatkin, Dmitry
2011-12-02 18:46 ` [PATCH 17/21] KEYS: PGP format signature parser " David Howells
2011-12-02 18:46 ` [PATCH 18/21] KEYS: Provide a function to load keys from a PGP keyring blob " David Howells
2011-12-02 18:46 ` [PATCH 19/21] MODSIGN: Add indications of module ELF types " David Howells
2011-12-02 18:46 ` [PATCH 20/21] MODSIGN: Module ELF verifier " David Howells
2011-12-02 18:46 ` [PATCH 21/21] MODSIGN: Apply signature checking to modules on module load " David Howells
2011-12-09 11:18 ` Rusty Russell [this message]
2011-12-09 18:43 ` David Howells
2011-12-10 7:01 ` Rusty Russell
2011-12-10 18:37 ` Arjan van de Ven
2011-12-11 4:59 ` Rusty Russell
2011-12-10 14:08 ` David Howells
2011-12-11 4:57 ` Rusty Russell
2011-12-12 1:21 ` David Howells
2011-12-12 9:09 ` Rusty Russell
2011-12-12 16:11 ` David Howells
2011-12-13 2:15 ` Rusty Russell
2011-12-15 0:14 ` David Howells
2011-12-16 0:41 ` Rusty Russell
2012-01-08 22:02 ` [RFC][PATCH 00/21] Crypto keys and module signing " Mimi Zohar
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