4:37 a.m.
On Tue, May 28, 2019 at 10:14:01AM +0100, Richard W.M. Jones wrote:
On Mon, May 27, 2019 at 01:30:05PM +0200, Martin Kletzander wrote:
> While svirt_t can be used for sockets it does not always guarantee that it will
> be accessible from a virtual machine. The VM might be running under svirt_tcg_t
> context which will need a svirt_tcg_t label on the socket in order to access it.
I don't really know enough about SELinux or the sVirt policy to
comment on this, but it's plausible so I'll push it soon, thanks.
I dug through this for quite a while, but I still cannot see why is there a
difference between svirt_t and svirt_tcg_t (except maybe /dev/kvm context).
But I created a build with this patch in for the reporter of the bug and they
tested it and it worked. I also took some time to look at the policies (and had
to learn what a "type attribute" is, see below) to make sure this is as close
to
how it should work as I, myself, can get.
One thing I would like to get some feedback on, although I believe it is not
required for this patch's justification, is some information about what each
context is supposed to mean or be used for. I was pretty confident about what
svirt_t is supposed to be used for, but when I have seen that svirt_t is defined
for the unix_stream_socket target class as well, while being defined for
virt_domain type attribute as well, does not really make sense to me.
Anyway, thanks.
Martin
Rich.
> There is, however, another label, svirt_socket_t, which is accessible from
> virt_domain:
>
> # sesearch -A -s svirt_t -c unix_stream_socket -p connectto
> ...
> allow virt_domain svirt_socket_t:unix_stream_socket { ... connectto ... };
> ...
>
> And virt_domain is a type attribute of both svirt_t and svirt_tcg_t:
>
> # seinfo -x -a virt_domain
> Type Attributes: 1
> attribute virt_domain;
> svirt_t
> svirt_tcg_t
>
> Resolves: https://bugzilla.redhat.com/1698437
>
> Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com>
> ---
> v2v/input_libvirt_vddk.ml | 2 +-
> v2v/output_rhv_upload.ml | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/v2v/input_libvirt_vddk.ml b/v2v/input_libvirt_vddk.ml
> index e2efef842e8e..4e36ff71f783 100644
> --- a/v2v/input_libvirt_vddk.ml
> +++ b/v2v/input_libvirt_vddk.ml
> @@ -286,7 +286,7 @@ object
> add_arg "--newstyle"; (* use newstyle NBD protocol *)
> add_arg "--exportname"; add_arg "/";
> if have_selinux then ( (* label the socket so qemu can open it *)
> - add_arg "--selinux-label"; add_arg
"system_u:object_r:svirt_t:s0"
> + add_arg "--selinux-label"; add_arg
"system_u:object_r:svirt_socket_t:s0"
> );
>
> (* Name of the plugin. Everything following is a plugin parameter. *)
> diff --git a/v2v/output_rhv_upload.ml b/v2v/output_rhv_upload.ml
> index 0709c8152c4e..5bc6a400725b 100644
> --- a/v2v/output_rhv_upload.ml
> +++ b/v2v/output_rhv_upload.ml
> @@ -213,7 +213,7 @@ See also the virt-v2v-output-rhv(1) manual.")
> let args =
> (* label the socket so qemu can open it *)
> if have_selinux then
> - args @ ["--selinux-label";
"system_u:object_r:svirt_t:s0"]
> + args @ ["--selinux-label";
"system_u:object_r:svirt_socket_t:s0"]
> else args in
> args in
>
> --
> 2.21.0
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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