[libvirt] [PATCH V3] apparmor: support ptrace checks

[Jim Fehlig]

Kernel 4.13 introduced finer-grained ptrace checks

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/?h=v4.13.2&id=290f458a4f16f9cf6cb6562b249e69fe1c3c3a07

With kernel 4.13 and apparmor 2.11, simply starting libvirtd
results in the following apparmor denial

type=AVC msg=audit(1506112085.645:954): apparmor="DENIED"
operation="ptrace" profile="/usr/sbin/libvirtd" pid=6984
comm="libvirtd" requested_mask="trace" denied_mask="trace"
peer="unconfined"

Attempting to start an unconfined domain results in

type=AVC msg=audit(1506112301.227:1112): apparmor="DENIED"
operation="ptrace" profile="/usr/sbin/libvirtd" pid=7498
comm="libvirtd" requested_mask="trace" denied_mask="trace"
peer="/usr/sbin/libvirtd"

And attempting to start a confined domain results in

type=AVC msg=audit(1506112631.408:1312): apparmor="DENIED"
operation="open" profile="virt-aa-helper" name="/etc/libnl/classid"
pid=8283 comm="virt-aa-helper" requested_mask="r" denied_mask="r"
fsuid=0 ouid=0
type=AVC msg=audit(1506112631.530:1319): apparmor="DENIED"
operation="open" profile="virt-aa-helper" name="/etc/libnl/classid"
pid=8289 comm="virt-aa-helper" requested_mask="r" denied_mask="r"
fsuid=0 ouid=0
type=AVC msg=audit(1506112632.186:1324): apparmor="DENIED"
operation="ptrace" profile="/usr/sbin/libvirtd" pid=8342
comm="libvirtd" requested_mask="trace" denied_mask="trace"
peer="libvirt-66154842-e926-4f92-92f0-1c1bf61dd1ff"

Add ptrace rules to allow the trace operations.

Resolves: https://bugzilla.suse.com/show_bug.cgi?id=1058847
Signed-off-by: Jim Fehlig <jfehlig at suse.com>
---

V3:
 fix ptrace rule for per-domain profiles

V2:
 restrict ptrace permissions
 drop support for dbus, signal, and unix
 
 examples/apparmor/usr.sbin.libvirtd | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/examples/apparmor/usr.sbin.libvirtd b/examples/apparmor/usr.sbin.libvirtd
index acb59e071..fa4ebb355 100644
--- a/examples/apparmor/usr.sbin.libvirtd
+++ b/examples/apparmor/usr.sbin.libvirtd
@@ -37,6 +37,10 @@
   network packet dgram,
   network packet raw,
 
+  ptrace (trace) peer=unconfined,
+  ptrace (trace) peer=/usr/sbin/libvirtd,
+  ptrace (trace) peer=libvirt-*,
+
   # Very lenient profile for libvirtd since we want to first focus on confining
   # the guests. Guests will have a very restricted profile.
   / r,
-- 
2.14.1