Quoting Jamie Strandboge <jamie@xxxxxxxxxxxxx>:
On Tue, 2012-07-03 at 12:05 -0400, rmarwah@xxxxxxxxxxxxxxxxxx wrote:
Quoting Jamie Strandboge <jamie@xxxxxxxxxxxxx>:
> On Fri, 2012-06-29 at 14:08 -0400, rmarwah@xxxxxxxxxxxxxxxxxx wrote:
>> From: Richa Marwaha <rmarwah@xxxxxxxxxxxxxxxxxx>
>>
>> This patch provides AppArmor policy updates for the QEMU bridge helper.
>> The QEMU bridge helper is a SUID executable exec'd by QEMU that drops
>> capabilities to CAP_NET_ADMIN and adds a tap device to a network bridge.
>>
>> Signed-off-by: Richa Marwaha <rmarwah@xxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Corey Bryant<coreyb@xxxxxxxxxxxxxxxxxx>
>> ---
>> examples/apparmor/libvirt-qemu | 21 ++++++++++++++++++++-
>> 1 files changed, 20 insertions(+), 1 deletions(-)
>>
>> diff --git a/examples/apparmor/libvirt-qemu
b/examples/apparmor/libvirt-qemu
>> index 10cdd36..766a334 100644
>> --- a/examples/apparmor/libvirt-qemu
>> +++ b/examples/apparmor/libvirt-qemu
>> @@ -1,4 +1,4 @@
>> -# Last Modified: Mon Apr 5 15:11:27 2010
>> +# Last Modified: Fri Mar 9 14:43:22 2012
>>
>> #include <abstractions/base>
>> #include <abstractions/consoles>
>> @@ -108,3 +108,22 @@
>> /bin/dash rmix,
>> /bin/dd rmix,
>> /bin/cat rmix,
>> +
>> + /usr/libexec/qemu-bridge-helper Cx,
>> + # child profile for bridge helper process
>> + profile /usr/libexec/qemu-bridge-helper {
>> + #include <abstractions/base>
>> +
>> + capability setuid,
>> + capability setgid,
>> + capability setpcap,
>> + capability net_admin,
>> +
>> + network inet stream,
>> +
>> + /dev/net/tun rw,
>> + /etc/qemu/** r,
>> + owner @{PROC}/*/status r,
>> +
>> + /usr/libexec/qemu-bridge-helper rmix,
>> + }
>
> Looking at the child profile itself, this seems fine.
>
> However, the Cx transition makes it so that all libvirt-managed qemu
> processes are allowed to execute this setuid helper and I wonder if that
> is too much? Ie, a guest running under libvirt's NAT wouldn't need
> access to this helper at all. I wonder if it would be better to adjust
> virt-aa-helper to add this transition and child profile instead (the
> child profile could theoretically still be in apparmor/libvirt-qemu, but
> this is a bit messy)? Can we determine from the domain XML the
> circumstances when /usr/libexec/qemu-bridge-helper will be used? If so,
> virt-aa-helper could add the access only then. As a side-benefit,
> handling this in virt-aa-helper allows us at compile-time to adjust the
> path to qemu-bridge-helper to use the configured path to the binary (ie,
> some distros may not use /usr/libexec).
Thanks a lot reviewing the apparmor patch. We cannot detemine from the
domain XML whether /usr/libexec/qemu-bridge-helper will be used or not
because we cannot determine whether we are running as privileged user
or not.
Hmmm, that's too bad.
Is there a way we can specify the configured path to the
binary in the current policy we have?
Not in a convenient way, no. The policy is intended as example policy
anyway, and distributions are expected to modify this, so I don't think
this alone is a blocker.
Right now the only way we can think of is that whenever in domain XML
we see interface=bridge
we set the policy for the qemu-bridge-helper even though we don't know
if the qemu-bridge-helper
is going to be used or not.
Thanks
Regards
Richa Marwaha
--
Jamie Strandboge | http://www.canonical.com
--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list