Documentation and examples for SVirt Apparmor driver

* docs/drvqemu.html.in: include documentation for AppArmor sVirt
  confinement
* examples/apparmor/TEMPLATE examples/apparmor/libvirt-qemu
  examples/apparmor/usr.lib.libvirt.virt-aa-helper
  examples/apparmor/usr.sbin.libvirtd: example templates and
  configuration files for SVirt Apparmor when using KVM/QEmu

docs/drvqemu.html.in

@@ -296,6 +296,73 @@
       file can be used to change the setting to <code>security_driver="none"</code>
     </p>
 
+    <h3><a name="securitysvirtaa">AppArmor sVirt confinement</a></h3>
+
+    <p>
+      When using basic AppArmor protection for the libvirtd daemon and
+      QEMU virtual machines, the intention is to protect the host OS
+      from a compromised virtual machine process. There is no protection
+      between guests.
+    </p>
+
+    <p>
+      The AppArmor sVirt protection for QEMU virtual machines builds on
+      this basic level of protection, to also allow individual guests to
+      be protected from each other.
+    </p>
+
+    <p>
+      In the sVirt model, if a profile is loaded for the libvirtd daemon,
+      then each <code>qemu:///system</code> QEMU virtual machine will have
+      a profile created for it when the virtual machine is started if one
+      does not already exist. This generated profile uses a profile name
+      based on the UUID of the QEMU virtual machine and contains rules
+      allowing access to only the files it needs to run, such as its disks,
+      pid file and log files. Just before the QEMU virtual machine is
+      started, the libvirtd daemon will change into this unique profile,
+      preventing the QEMU process from accessing any file resources that
+      are present in another QEMU process or the host machine.
+    </p>
+
+    <p>
+      The AppArmor sVirt implementation is flexible in that it allows an
+      administrator to customize the template file in
+      <code>/etc/apparmor.d/libvirt/TEMPLATE</code> for site-specific
+      access for all newly created QEMU virtual machines. Also, when a new
+      profile is generated, two files are created:
+      <code>/etc/apparmor.d/libvirt/libvirt-&lt;uuid&gt;</code> and
+      <code>/etc/apparmor.d/libvirt/libvirt-&lt;uuid&gt;.files</code>. The
+      former can be fine-tuned by the administrator to allow custom access
+      for this particular QEMU virtual machine, and the latter will be
+      updated appropriately when required file access changes, such as when
+      a disk is added. This flexibility allows for situations such as
+      having one virtual machine in complain mode with all others in
+      enforce mode.
+    </p>
+
+    <p>
+      While users can define their own AppArmor profile scheme, a typical
+      configuration will include a profile for <code>/usr/sbin/libvirtd</code>,
+      <code>/usr/lib/libvirt/virt-aa-helper</code> (a helper program which the
+      libvirtd daemon uses instead of manipulating AppArmor directly), and
+      an abstraction to be included by <code>/etc/apparmor.d/libvirt/TEMPLATE</code>
+      (typically <code>/etc/apparmor.d/abstractions/libvirt-qemu</code>).
+      An example profile scheme can be found in the examples/apparmor
+      directory of the source distribution.
+    </p>
+
+    <p>
+      If the sVirt security model is active, then the node capabilities
+      XML will include its details. If a virtual machine is currently
+      protected by the security model, then the guest XML will include
+      its assigned profile name. If enabled at compile time, the sVirt
+      security model will be activated if AppArmor is available on the host
+      OS and a profile for the libvirtd daemon is loaded when libvirtd is
+      started. To disable sVirt, and revert to the basic level of AppArmor
+      protection (host protection only), the <code>/etc/libvirt/qemu.conf</code>
+      file can be used to change the setting to <code>security_driver="none"</code>.
+    </p>
+
 
     <h3><a name="securityacl">Cgroups device ACLs</a></h3>
 

examples/apparmor/TEMPLATE

+#
+# This profile is for the domain whose UUID matches this file.
+#
+
+#include <tunables/global>
+
+profile LIBVIRT_TEMPLATE {
+  #include <abstractions/libvirt-qemu>
+}

examples/apparmor/libvirt-qemu

+# Last Modified: Wed Jul  8 09:57:41 2009
+
+  #include <abstractions/base>
+  #include <abstractions/consoles>
+  #include <abstractions/nameservice>
+
+  # required for reading disk images
+  capability dac_override,
+  capability dac_read_search,
+  capability chown,
+
+  network inet stream,
+  network inet6 stream,
+
+  /dev/net/tun rw,
+  /dev/kvm rw,
+  /dev/ptmx rw,
+  /dev/kqemu rw,
+
+  # WARNING: uncommenting these gives the guest direct access to host hardware.
+  # This is required for USB pass through but is a security risk. You have been
+  # warned.
+  #/sys/bus/usb/devices/ r,
+  #/sys/devices/*/*/usb[0-9]*/** r,
+  #/dev/bus/usb/*/[0-9]* rw,
+
+  /usr/share/kvm/** r,
+  /usr/share/qemu/** r,
+  /usr/share/bochs/** r,
+  /usr/share/openbios/** r,
+  /usr/share/openhackware/** r,
+  /usr/share/proll/** r,
+  /usr/share/vgabios/** r,
+
+  # the various binaries
+  /usr/bin/kvm rmix,
+  /usr/bin/qemu rmix,
+  /usr/bin/qemu-system-arm rmix,
+  /usr/bin/qemu-system-cris rmix,
+  /usr/bin/qemu-system-i386 rmix,
+  /usr/bin/qemu-system-m68k rmix,
+  /usr/bin/qemu-system-mips rmix,
+  /usr/bin/qemu-system-mips64 rmix,
+  /usr/bin/qemu-system-mips64el rmix,
+  /usr/bin/qemu-system-mipsel rmix,
+  /usr/bin/qemu-system-ppc rmix,
+  /usr/bin/qemu-system-ppc64 rmix,
+  /usr/bin/qemu-system-ppcemb rmix,
+  /usr/bin/qemu-system-sh4 rmix,
+  /usr/bin/qemu-system-sh4eb rmix,
+  /usr/bin/qemu-system-sparc rmix,
+  /usr/bin/qemu-system-sparc64 rmix,
+  /usr/bin/qemu-system-x86_64 rmix,
+  /usr/bin/qemu-alpha rmix,
+  /usr/bin/qemu-arm rmix,
+  /usr/bin/qemu-armeb rmix,
+  /usr/bin/qemu-cris rmix,
+  /usr/bin/qemu-i386 rmix,
+  /usr/bin/qemu-m68k rmix,
+  /usr/bin/qemu-mips rmix,
+  /usr/bin/qemu-mipsel rmix,
+  /usr/bin/qemu-ppc rmix,
+  /usr/bin/qemu-ppc64 rmix,
+  /usr/bin/qemu-ppc64abi32 rmix,
+  /usr/bin/qemu-sh4 rmix,
+  /usr/bin/qemu-sh4eb rmix,
+  /usr/bin/qemu-sparc rmix,
+  /usr/bin/qemu-sparc64 rmix,
+  /usr/bin/qemu-sparc32plus rmix,
+  /usr/bin/qemu-sparc64 rmix,
+  /usr/bin/qemu-x86_64 rmix,

examples/apparmor/usr.lib.libvirt.virt-aa-helper

+# Last Modified: Mon Jul  06 17:22:37 2009
+#include <tunables/global>
+
+/usr/lib/libvirt/virt-aa-helper {
+  #include <abstractions/base>
+
+  # needed for searching directories
+  capability dac_override,
+  capability dac_read_search,
+
+  # needed for when disk is on a network filesystem
+  network inet,
+
+  deny @{PROC}/[0-9]*/mounts r,
+  @{PROC}/filesystems r,
+
+  /usr/lib/libvirt/virt-aa-helper mr,
+  /sbin/apparmor_parser Ux,
+
+  /etc/apparmor.d/libvirt/* r,
+  /etc/apparmor.d/libvirt/libvirt-[0-9a-f]*-[0-9a-f]*-[0-9a-f]*-[0-9a-f]*-[0-9a-f]* rw,
+}

examples/apparmor/usr.sbin.libvirtd

+# Last Modified: Wed Sep 23 23:23:58 2009
+#include <tunables/global>
+@{LIBVIRT}="libvirt"
+
+/usr/sbin/libvirtd {
+  #include <abstractions/base>
+
+  capability kill,
+  capability net_admin,
+  capability net_raw,
+  capability setgid,
+  capability sys_admin,
+  capability sys_module,
+  capability sys_ptrace,
+  capability sys_nice,
+  capability sys_chroot,
+  capability setuid,
+  capability dac_override,
+  capability dac_read_search,
+  capability fowner,
+  capability chown,
+  capability setpcap,
+  capability mknod,
+
+  network inet stream,
+
+  # Very lenient profile for libvirtd since we want to first focus on confining
+  # the guests. Guests will have a very restricted profile.
+  /** rwmkl,
+
+  /bin/* Ux,
+  /sbin/* Ux,
+  /usr/bin/* Ux,
+  /usr/sbin/* Ux,
+
+  # force the use of virt-aa-helper
+  audit deny /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/libvirt/virt-aa-helper Pxr,
+
+  # 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]*,
+
+}