[xen staging] flask: implement xsm_set_system_active

[patchbot@xxxxxxx]

commit a0bb0960e5ed2d6b59aff5c0eae74d8347bab32b
Author:     Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
AuthorDate: Mon Jul 4 14:47:00 2022 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Jul 4 14:47:00 2022 +0200

    flask: implement xsm_set_system_active
    
    This commit implements full support for starting the idle domain privileged 
by
    introducing a new flask label xenboot_t which the idle domain is labeled 
with
    at creation.  It then provides the implementation for the XSM hook
    xsm_set_system_active to relabel the idle domain to the existing xen_t flask
    label.
    
    In the reference flask policy a new macro, xen_build_domain(target), is
    introduced for creating policies for dom0less/hyperlaunch allowing the
    hypervisor to create and assign the necessary resources for domain
    construction.
    
    Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
    Reviewed-by: Jason Andryuk <jandryuk@xxxxxxxxx>
    Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx>
    Tested-by: Luca Fancellu <luca.fancellu@xxxxxxx>
    Reviewed-by: Rahul Singh <rahul.singh@xxxxxxx>
    Tested-by: Rahul Singh <rahul.singh@xxxxxxx>
---
 tools/flask/policy/modules/xen.if      | 7 +++++++
 tools/flask/policy/modules/xen.te      | 1 +
 tools/flask/policy/policy/initial_sids | 1 +
 xen/xsm/flask/hooks.c                  | 9 ++++++++-
 xen/xsm/flask/policy/initial_sids      | 1 +
 5 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/tools/flask/policy/modules/xen.if 
b/tools/flask/policy/modules/xen.if
index 5e2aa472b6..424daab6a0 100644
--- a/tools/flask/policy/modules/xen.if
+++ b/tools/flask/policy/modules/xen.if
@@ -62,6 +62,13 @@ define(`create_domain_common', `
                        setparam altp2mhvm altp2mhvm_op dm };
 ')
 
+# xen_build_domain(target)
+#   Allow a domain to be created at boot by the hypervisor
+define(`xen_build_domain', `
+       allow xenboot_t $1:domain create;
+       allow xenboot_t $1_channel:event create;
+')
+
 # create_domain(priv, target)
 #   Allow a domain to be created directly
 define(`create_domain', `
diff --git a/tools/flask/policy/modules/xen.te 
b/tools/flask/policy/modules/xen.te
index 3dbf93d2b8..de98206fdd 100644
--- a/tools/flask/policy/modules/xen.te
+++ b/tools/flask/policy/modules/xen.te
@@ -24,6 +24,7 @@ attribute mls_priv;
 
################################################################################
 
 # The hypervisor itself
+type xenboot_t, xen_type, mls_priv;
 type xen_t, xen_type, mls_priv;
 
 # Domain 0
diff --git a/tools/flask/policy/policy/initial_sids 
b/tools/flask/policy/policy/initial_sids
index 6b7b7eff21..ec729d3ba3 100644
--- a/tools/flask/policy/policy/initial_sids
+++ b/tools/flask/policy/policy/initial_sids
@@ -2,6 +2,7 @@
 # objects created before the policy is loaded or for objects that do not have a
 # label defined in some other manner.
 
+sid xenboot gen_context(system_u:system_r:xenboot_t,s0)
 sid xen gen_context(system_u:system_r:xen_t,s0)
 sid dom0 gen_context(system_u:system_r:dom0_t,s0)
 sid domxen gen_context(system_u:system_r:domxen_t,s0)
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index c97c44f803..8c9cd0f297 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -173,7 +173,7 @@ static int cf_check flask_domain_alloc_security(struct 
domain *d)
     switch ( d->domain_id )
     {
     case DOMID_IDLE:
-        dsec->sid = SECINITSID_XEN;
+        dsec->sid = SECINITSID_XENBOOT;
         break;
     case DOMID_XEN:
         dsec->sid = SECINITSID_DOMXEN;
@@ -193,9 +193,14 @@ static int cf_check flask_domain_alloc_security(struct 
domain *d)
 
 static int cf_check flask_set_system_active(void)
 {
+    struct domain_security_struct *dsec;
     struct domain *d = current->domain;
 
+    dsec = d->ssid;
+
     ASSERT(d->is_privileged);
+    ASSERT(dsec->sid == SECINITSID_XENBOOT);
+    ASSERT(dsec->self_sid == SECINITSID_XENBOOT);
 
     if ( d->domain_id != DOMID_IDLE )
     {
@@ -210,6 +215,8 @@ static int cf_check flask_set_system_active(void)
      */
     d->is_privileged = false;
 
+    dsec->self_sid = dsec->sid = SECINITSID_XEN;
+
     return 0;
 }
 
diff --git a/xen/xsm/flask/policy/initial_sids 
b/xen/xsm/flask/policy/initial_sids
index 7eca70d339..e8b55b8368 100644
--- a/xen/xsm/flask/policy/initial_sids
+++ b/xen/xsm/flask/policy/initial_sids
@@ -3,6 +3,7 @@
 #
 # Define initial security identifiers 
 #
+sid xenboot
 sid xen
 sid dom0
 sid domio
--
generated by git-patchbot for /home/xen/git/xen.git#staging