On Fri, 2012-06-29 at 14:08 -0400, rmarwah(a)linux.vnet.ibm.com wrote:
From: Richa Marwaha <rmarwah(a)linux.vnet.ibm.com>
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(a)linux.vnet.ibm.com>
Signed-off-by: Corey Bryant<coreyb(a)linux.vnet.ibm.com>
---
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).
--
Jamie Strandboge |
http://www.canonical.com