[PATCH v2 15/18] xsm, argo: XSM control for any access to argo by a domain

[Christopher Clark <christopher.w.clark@gmail.com>]

Will inhibit initialization of the domain's argo data structure to
prevent receiving any messages or notifications and access to any of
the argo hypercall operations.

Signed-off-by: Christopher Clark <christopher.clark6@baesystems.com>
---
Changes since v1:

v1 #5 (#17) feedback Paul: XSM control for any access: use currd
v1 #16 feedback Jan: apply const to function signatures

 xen/common/argo.c                   | 4 ++--
 xen/include/xsm/dummy.h             | 5 +++++
 xen/include/xsm/xsm.h               | 6 ++++++
 xen/xsm/dummy.c                     | 1 +
 xen/xsm/flask/hooks.c               | 7 +++++++
 xen/xsm/flask/policy/access_vectors | 3 +++
 6 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/xen/common/argo.c b/xen/common/argo.c
index 6fbd0a6..1f16872 100644
--- a/xen/common/argo.c
+++ b/xen/common/argo.c
@@ -1981,7 +1981,7 @@ do_argo_message_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) arg1,
     argo_dprintk("->do_argo_message_op(%u,%p,%p,%d,%d)\n", cmd,
                  (void *)arg1.p, (void *)arg2.p, (int) arg3, (int) arg4);
 
-    if ( unlikely(!opt_argo_enabled) )
+    if ( unlikely(!opt_argo_enabled || xsm_argo_enable(currd)) )
     {
         rc = -EOPNOTSUPP;
         return rc;
@@ -2119,7 +2119,7 @@ argo_init(struct domain *d)
 {
     struct argo_domain *argo;
 
-    if ( !opt_argo_enabled )
+    if ( !opt_argo_enabled || xsm_argo_enable(d) )
     {
         argo_dprintk("argo disabled, domid: %d\n", d->domain_id);
         return 0;
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index 05d10b5..91a21c3 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -721,6 +721,11 @@ static XSM_INLINE int xsm_dm_op(XSM_DEFAULT_ARG struct domain *d)
 #endif /* CONFIG_X86 */
 
 #ifdef CONFIG_ARGO
+static XSM_INLINE int xsm_argo_enable(struct domain *d)
+{
+    return 0;
+}
+
 static XSM_INLINE int xsm_argo_register_single_source(struct domain *d,
                                                       struct domain *t)
 {
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index 4d4a60c..e300ebc 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -182,6 +182,7 @@ struct xsm_operations {
     int (*xen_version) (uint32_t cmd);
     int (*domain_resource_map) (struct domain *d);
 #ifdef CONFIG_ARGO
+    int (*argo_enable) (const struct domain *d);
     int (*argo_register_single_source) (const struct domain *d,
                                         const struct domain *t);
     int (*argo_register_any_source) (const struct domain *d);
@@ -705,6 +706,11 @@ static inline int xsm_domain_resource_map(xsm_default_t def, struct domain *d)
 }
 
 #ifdef CONFIG_ARGO
+static inline xsm_argo_enable(const struct domain *d)
+{
+    return xsm_ops->argo_enable(d);
+}
+
 static inline xsm_argo_register_single_source(const struct domain *d,
                                               const struct domain *t)
 {
diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
index ffac774..1fe0e74 100644
--- a/xen/xsm/dummy.c
+++ b/xen/xsm/dummy.c
@@ -153,6 +153,7 @@ void __init xsm_fixup_ops (struct xsm_operations *ops)
     set_to_dummy_if_null(ops, xen_version);
     set_to_dummy_if_null(ops, domain_resource_map);
 #ifdef CONFIG_ARGO
+    set_to_dummy_if_null(ops, argo_enable);
     set_to_dummy_if_null(ops, argo_register_single_source);
     set_to_dummy_if_null(ops, argo_register_any_source);
     set_to_dummy_if_null(ops, argo_send);
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 76c012c..3d00c74 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -1720,6 +1720,12 @@ static int flask_domain_resource_map(struct domain *d)
 }
 
 #ifdef CONFIG_ARGO
+static int flask_argo_enable(const struct domain *d)
+{
+    return avc_has_perm(domain_sid(d), SECINITSID_XEN, SECCLASS_ARGO,
+                        ARGO__ENABLE, NULL);
+}
+
 static int flask_argo_register_single_source(const struct domain *d,
                                              const struct domain *t)
 {
@@ -1875,6 +1881,7 @@ static struct xsm_operations flask_ops = {
     .xen_version = flask_xen_version,
     .domain_resource_map = flask_domain_resource_map,
 #ifdef CONFIG_ARGO
+    .argo_enable = flask_argo_enable,
     .argo_register_single_source = flask_argo_register_single_source,
     .argo_register_any_source = flask_argo_register_any_source,
     .argo_send = flask_argo_send,
diff --git a/xen/xsm/flask/policy/access_vectors b/xen/xsm/flask/policy/access_vectors
index f6c5377..e00448b 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -535,6 +535,9 @@ class version
 # Class argo is used to describe the Argo interdomain communication system.
 class argo
 {
+    # Enable initialization of a domain's argo subsystem and
+    # permission to access the argo hypercall operations.
+    enable
     # Domain requesting registration of a communication ring
     # to receive messages from a specific other domain.
     register_single_source
-- 
2.7.4


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