From: "Jan Beulich" <jbeulich@novell.com>
Subject: Re: [PATCH] linux: prevent non-Xen modules
	fromloading in Xen kernel
Date: Fri, 18 Jan 2008 15:48:17 +0000
Message-ID: <4790D851.76E4.0078.0@novell.com>
References: <4790CB11.76E4.0078.0@novell.com>
	<C3B677C9.1B080%Keir.Fraser@cl.cam.ac.uk>
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To: Keir Fraser <Keir.Fraser@cl.cam.ac.uk>
Cc: Zachary Amsden <zach@vmware.com>, xen-devel@lists.xensource.com
List-Id: xen-devel@lists.xenproject.org

It's intended to disallow cross-version loading of modules (i.e. a module
compiled against a kernel built with a different [lower or higher] Xen
interface) - allowing such can be as dangerous as loading a module that
was compiled against native I believe.

Jan

>>> Keir Fraser <Keir.Fraser@cl.cam.ac.uk> 18.01.08 16:35 >>>
Does the XEN_INTERFACE_VERSION add anything? It has not much to do with =
the
module<->Linux-core interface. Seems a pretty random thing to stuff into =
the
module magic version string.

 -- Keir

On 18/1/08 14:51, "Jan Beulich" <jbeulich@novell.com> wrote:

> .. and vice versa.
>=20
> Inspired by Zach Amsden's functionally similar VMI patch.
>=20
> As usual, written and tested on 2.6.24-rc7 and made apply to the 2.6.18
> tree without further testing.
>=20
> Signed-off-by: Jan Beulich <jbeulich@novell.com>
>=20
> Index: head-2008-01-08/drivers/xen/Kconfig
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- head-2008-01-08.orig/drivers/xen/Kconfig 2008-01-08 12:26:03.00000000=
0
> +0100
> +++ head-2008-01-08/drivers/xen/Kconfig 2008-01-08 14:56:58.000000000 =
+0100
> @@ -13,7 +13,7 @@ config XEN
>  if XEN
>  config XEN_INTERFACE_VERSION
> hex
> - default 0x00030207
> + default 0x30207
> =20
>  menu "XEN"
> =20
> Index: head-2008-01-08/include/linux/vermagic.h
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- head-2008-01-08.orig/include/linux/vermagic.h 2006-11-29
> 22:57:37.000000000 +0100
> +++ head-2008-01-08/include/linux/vermagic.h 2008-01-08 15:01:52.00000000=
0
> +0100
> @@ -17,6 +17,11 @@
>  #else
>  #define MODULE_VERMAGIC_MODULE_UNLOAD ""
>  #endif
> +#ifdef CONFIG_XEN
> +#define MODULE_VERMAGIC_XEN "Xen:" __stringify(CONFIG_XEN_INTERFACE_VERS=
ION)
> " "
> +#else
> +#define MODULE_VERMAGIC_XEN
> +#endif
>  #ifndef MODULE_ARCH_VERMAGIC
>  #define MODULE_ARCH_VERMAGIC ""
>  #endif
> @@ -24,5 +29,6 @@
>  #define VERMAGIC_STRING       \
> UTS_RELEASE " "       \
> MODULE_VERMAGIC_SMP MODULE_VERMAGIC_PREEMPT    \
> - MODULE_VERMAGIC_MODULE_UNLOAD MODULE_ARCH_VERMAGIC   \
> + MODULE_VERMAGIC_MODULE_UNLOAD MODULE_VERMAGIC_XEN  \
> + MODULE_ARCH_VERMAGIC      \
> "gcc-" __stringify(__GNUC__) "." __stringify(__GNUC_MINOR__)
>=20
>=20
>=20
>=20
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