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[Xen-devel] [PATCH 02/23] flask/policy: Add domain relabel example



This adds the nomigrate_t type to the example FLASK policy which allows
domains to be created that dom0 cannot access after building.

Example domain configuration snippet:
  seclabel='customer_1:vm_r:nomigrate_t'
  init_seclabel='customer_1:vm_r:nomigrate_t_building'

Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
 docs/misc/xsm-flask.txt                      |  2 +
 tools/flask/policy/policy/modules/xen/xen.if | 56 +++++++++++++++++++++-------
 tools/flask/policy/policy/modules/xen/xen.te | 10 +++++
 3 files changed, 55 insertions(+), 13 deletions(-)

diff --git a/docs/misc/xsm-flask.txt b/docs/misc/xsm-flask.txt
index 6b0d327..0778a28 100644
--- a/docs/misc/xsm-flask.txt
+++ b/docs/misc/xsm-flask.txt
@@ -60,6 +60,8 @@ that can be used without dom0 disaggregation. The main types 
for domUs are:
  - domU_t is a domain that can communicate with any other domU_t
  - isolated_domU_t can only communicate with dom0
  - prot_domU_t is a domain type whose creation can be disabled with a boolean
+ - nomigrate_t is a domain that must be created via the nomigrate_t_building
+   type, and whose memory cannot be read by dom0 once created
 
 HVM domains with stubdomain device models use two types (one per domain):
  - domHVM_t is an HVM domain that uses a stubdomain device model
diff --git a/tools/flask/policy/policy/modules/xen/xen.if 
b/tools/flask/policy/policy/modules/xen/xen.if
index 3f58909..2ad11b2 100644
--- a/tools/flask/policy/policy/modules/xen/xen.if
+++ b/tools/flask/policy/policy/modules/xen/xen.if
@@ -9,24 +9,47 @@
 #   Declare a type as a domain type, and allow basic domain setup
 define(`declare_domain', `
        type $1, domain_type`'ifelse(`$#', `1', `', `,shift($@)');
+       type $1_channel, event_type;
+       type_transition $1 domain_type:event $1_channel;
        allow $1 $1:grant { query setup };
        allow $1 $1:mmu { adjust physmap map_read map_write stat pinpage };
        allow $1 $1:hvm { getparam setparam };
 ')
 
-# create_domain(priv, target)
-#   Allow a domain to be created
-define(`create_domain', `
+# declare_build_label(type)
+#   Declare a paired _building type for the given domain type
+define(`declare_build_label', `
+       type $1_building, domain_type;
+       type_transition $1_building domain_type:event $1_channel;
+       allow $1_building $1 : domain transition;
+')
+
+define(`create_domain_common', `
        allow $1 $2:domain { create max_vcpus setdomainmaxmem setaddrsize
-                       getdomaininfo hypercall setvcpucontext scheduler
-                       unpause getvcpuinfo getvcpuextstate getaddrsize
-                       getvcpuaffinity };
+                       getdomaininfo hypercall setvcpucontext setextvcpucontext
+                       scheduler getvcpuinfo getvcpuextstate getaddrsize
+                       getvcpuaffinity setvcpuaffinity };
        allow $1 $2:security check_context;
        allow $1 $2:shadow enable;
        allow $1 $2:mmu {map_read map_write adjust memorymap physmap pinpage};
        allow $1 $2:grant setup;
-       allow $1 $2:hvm { cacheattr getparam hvmctl irqlevel pciroute setparam 
pcilevel trackdirtyvram };
-       allow $1 $2_$1_channel:event create;
+       allow $1 $2:hvm { cacheattr getparam hvmctl irqlevel pciroute sethvmc 
setparam pcilevel trackdirtyvram };
+')
+
+# create_domain(priv, target)
+#   Allow a domain to be created directly
+define(`create_domain', `
+       create_domain_common($1, $2)
+       allow $1 $2_channel:event create;
+')
+
+# create_domain_build_label(priv, target)
+#   Allow a domain to be created via its domain build label
+define(`create_domain_build_label', `
+       create_domain_common($1, $2_building)
+       allow $1 $2_channel:event create;
+       allow $1 $2_building:domain2 relabelfrom;
+       allow $1 $2:domain2 relabelto;
 ')
 
 # manage_domain(priv, target)
@@ -37,6 +60,15 @@ define(`manage_domain', `
                        setvcpuaffinity setdomainmaxmem };
 ')
 
+# migrate_domain_out(priv, target)
+#   Allow creation of a snapshot or migration image from a domain
+#   (inbound migration is the same as domain creation)
+define(`migrate_domain_out', `
+       allow $1 $2:hvm { gethvmc getparam irqlevel };
+       allow $1 $2:mmu { stat pageinfo map_read };
+       allow $1 $2:domain { getaddrsize getvcpucontext getextvcpucontext 
getvcpuextstate pause destroy };
+')
+
 
################################################################################
 #
 # Inter-domain communication
@@ -47,8 +79,6 @@ define(`manage_domain', `
 #   This allows an event channel to be created from domains with labels
 #   <source> to <dest> and will label it <chan-label>
 define(`create_channel', `
-       type $3, event_type;
-       type_transition $1 $2:event $3;
        allow $1 $3:event { create send status };
        allow $3 $2:event { bind };
 ')
@@ -56,8 +86,8 @@ define(`create_channel', `
 # domain_event_comms(dom1, dom2)
 #   Allow two domain types to communicate using event channels
 define(`domain_event_comms', `
-       create_channel($1, $2, $1_$2_channel)
-       create_channel($2, $1, $2_$1_channel)
+       create_channel($1, $2, $1_channel)
+       create_channel($2, $1, $2_channel)
 ')
 
 # domain_comms(dom1, dom2)
@@ -72,7 +102,7 @@ define(`domain_comms', `
 #   Allow a domain types to communicate with others of its type using grants
 #   and event channels (this includes event channels to DOMID_SELF)
 define(`domain_self_comms', `
-       create_channel($1, $1, $1_self_channel)
+       create_channel($1, $1, $1_channel)
        allow $1 $1:grant { map_read map_write copy unmap };
 ')
 
diff --git a/tools/flask/policy/policy/modules/xen/xen.te 
b/tools/flask/policy/policy/modules/xen/xen.te
index 9550397..1162153 100644
--- a/tools/flask/policy/policy/modules/xen/xen.te
+++ b/tools/flask/policy/policy/modules/xen/xen.te
@@ -90,6 +90,7 @@ create_domain(dom0_t, isolated_domU_t)
 manage_domain(dom0_t, isolated_domU_t)
 domain_comms(dom0_t, isolated_domU_t)
 
+# Declare a boolean that denies creation of prot_domU_t domains
 gen_bool(prot_doms_locked, false)
 declare_domain(prot_domU_t)
 if (!prot_doms_locked) {
@@ -111,6 +112,15 @@ manage_domain(dom0_t, dm_dom_t)
 domain_comms(dom0_t, dm_dom_t)
 device_model(dm_dom_t, domHVM_t)
 
+# nomigrate_t must be built via the nomigrate_t_building label; once built,
+# dom0 cannot read its memory.
+declare_domain(nomigrate_t)
+declare_build_label(nomigrate_t)
+create_domain_build_label(dom0_t, nomigrate_t)
+manage_domain(dom0_t, nomigrate_t)
+domain_comms(dom0_t, nomigrate_t)
+domain_self_comms(nomigrate_t)
+
 ###############################################################################
 #
 # Device delegation
-- 
1.7.11.7


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