libvirt/examples/apparmor/usr.sbin.libvirtd
Jim Fehlig c44b29aacb apparmor: add dnsmasq ptrace rule to libvirtd profile
Commit b482925c added ptrace rule for the apparmor profiles,
but one was missed in the libvirtd profile for dnsmasq. It was
overlooked since the test machine did not have an active libvirt
network requiring dnsmasq that was also set to autostart. With
one active and set to autostart, the following denial is observed
in audit.log when restarting libvirtd

type=AVC msg=audit(1507320136.306:298): apparmor="DENIED" \
operation="ptrace" profile="/usr/sbin/libvirtd" pid=5472 \
comm="libvirtd" requested_mask="trace" denied_mask="trace" \
peer="/usr/sbin/dnsmasq"

With an active network, I suspect a libvirtd restart causes access
to /proc/<dnsmasq-pid>/*, hence the resulting denial. As a nasty
side affect of the denial, libvirtd thinks it needs to spawn a
dnsmasq process even though one is already running for the network.
E.g. after two libvirtd restarts

dnsmasq   1683  0.0  0.0  51188  2612 ?        S    12:03   0:00 \
 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf \
 --leasefile-ro --dhcp-script=/usr/lib64/libvirt/libvirt_leaseshelper
root      1684  0.0  0.0  51160   576 ?        S    12:03   0:00 \
 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf \
 --leasefile-ro --dhcp-script=/usr/lib64/libvirt/libvirt_leaseshelper
dnsmasq   4706  0.0  0.0  51188  2572 ?        S    13:54   0:00 \
 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf \
 --leasefile-ro --dhcp-script=/usr/lib64/libvirt/libvirt_leaseshelper
root      4707  0.0  0.0  51160   572 ?        S    13:54   0:00 \
 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf \
 --leasefile-ro --dhcp-script=/usr/lib64/libvirt/libvirt_leaseshelper
dnsmasq   4791  0.0  0.0  51188  2580 ?        S    13:56   0:00 \
 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf \
 --leasefile-ro --dhcp-script=/usr/lib64/libvirt/libvirt_leaseshelper
root      4792  0.0  0.0  51160   572 ?        S    13:56   0:00 \
 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf \
 --leasefile-ro --dhcp-script=/usr/lib64/libvirt/libvirt_leaseshelper

A simple fix is to add a ptrace rule for dnsmasq.

Signed-off-by: Jim Fehlig <jfehlig@suse.com>
Reviewed-By: Guido Günther <agx@sigxcpu.org>
2017-10-06 16:39:15 -06:00

95 lines
2.5 KiB
Plaintext

# Last Modified: Mon Apr 5 15:03:58 2010
#include <tunables/global>
@{LIBVIRT}="libvirt"
/usr/sbin/libvirtd flags=(attach_disconnected) {
#include <abstractions/base>
#include <abstractions/dbus>
capability kill,
capability net_admin,
capability net_raw,
capability setgid,
capability sys_admin,
capability sys_module,
capability sys_ptrace,
capability sys_pacct,
capability sys_nice,
capability sys_chroot,
capability setuid,
capability dac_override,
capability dac_read_search,
capability fowner,
capability chown,
capability setpcap,
capability mknod,
capability fsetid,
capability audit_write,
capability ipc_lock,
# Needed for vfio
capability sys_resource,
network inet stream,
network inet dgram,
network inet6 stream,
network inet6 dgram,
network packet dgram,
network packet raw,
ptrace (trace) peer=unconfined,
ptrace (trace) peer=/usr/sbin/libvirtd,
ptrace (trace) peer=/usr/sbin/dnsmasq,
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,
/** rwmkl,
/bin/* PUx,
/sbin/* PUx,
/usr/bin/* PUx,
/usr/sbin/virtlogd pix,
/usr/sbin/* PUx,
/{usr/,}lib/udev/scsi_id PUx,
/usr/{lib,lib64}/xen-common/bin/xen-toolstack PUx,
/usr/{lib,lib64}/xen/bin/* Ux,
/usr/lib/xen-*/bin/libxl-save-helper PUx,
# force the use of virt-aa-helper
audit deny /{usr/,}sbin/apparmor_parser rwxl,
audit deny /etc/apparmor.d/libvirt/** wxl,
audit deny /sys/kernel/security/apparmor/features rwxl,
audit deny /sys/kernel/security/apparmor/matching rwxl,
audit deny /sys/kernel/security/apparmor/.* rwxl,
/sys/kernel/security/apparmor/profiles r,
/usr/{lib,lib64}/libvirt/* PUxr,
/usr/{lib,lib64}/libvirt/libvirt_parthelper ix,
/usr/{lib,lib64}/libvirt/libvirt_iohelper ix,
/etc/libvirt/hooks/** rmix,
/etc/xen/scripts/** rmix,
# allow changing to our UUID-based named profiles
change_profile -> @{LIBVIRT}-[0-9a-f]*-[0-9a-f]*-[0-9a-f]*-[0-9a-f]*-[0-9a-f]*,
/usr/{lib,lib64,lib/qemu,libexec}/qemu-bridge-helper Cx -> qemu_bridge_helper,
# child profile for bridge helper process
profile 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/{lib,lib64,lib/qemu,libexec}/qemu-bridge-helper rmix,
}
}