[PATCH v7 12/15] xsm, argo: XSM control for argo message send operation

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

Default policy: allow.

Signed-off-by: Christopher Clark <christopher.clark6@baesystems.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Tested-by: Chris Patterson <pattersonc@ainfosec.com>
---
v3 Daniel/Jan: add to the default xsm policy for the send op
v3 Add Daniel's Acked-by
v2: reordered commit sequence to after sendv implementation
v1 feedback Jan #16: apply const to function signatures
v1 version was: Reviewed-by: Paul Durrant <paul.durrant@citrix.com>

 tools/flask/policy/modules/guest_features.te |  7 ++++---
 xen/common/argo.c                            | 11 +++++++++++
 xen/include/xsm/dummy.h                      |  6 ++++++
 xen/include/xsm/xsm.h                        |  6 ++++++
 xen/xsm/dummy.c                              |  1 +
 xen/xsm/flask/hooks.c                        |  7 +++++++
 xen/xsm/flask/policy/access_vectors          |  2 ++
 7 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/tools/flask/policy/modules/guest_features.te b/tools/flask/policy/modules/guest_features.te
index d00769e..ca52257 100644
--- a/tools/flask/policy/modules/guest_features.te
+++ b/tools/flask/policy/modules/guest_features.te
@@ -6,10 +6,11 @@ allow domain_type xen_t:xen tmem_op;
 allow domain_type xen_t:xen2 pmu_use;
 
 # Allow all domains:
-# to register single-sender (unicast) rings to partner with any domain; and
-# to register any-sender (wildcard) rings that can be sent to by any domain.
+# to register single-sender (unicast) rings to partner with any domain;
+# to register any-sender (wildcard) rings that can be sent to by any domain;
+# and send messages to rings.
 allow domain_type xen_t:argo { register_any_source };
-allow domain_type domain_type:argo { register_single_source };
+allow domain_type domain_type:argo { send register_single_source };
 
 # Allow guest console output to the serial console.  This is used by PV Linux
 # and stub domains for early boot output, so don't audit even when we deny it.
diff --git a/xen/common/argo.c b/xen/common/argo.c
index 5c1e711..b2a2b83 100644
--- a/xen/common/argo.c
+++ b/xen/common/argo.c
@@ -2014,6 +2014,17 @@ sendv(struct domain *src_d, xen_argo_addr_t *src_addr,
     if ( !dst_d )
         return -ESRCH;
 
+    ret = xsm_argo_send(src_d, dst_d);
+    if ( ret )
+    {
+        gprintk(XENLOG_ERR, "argo: XSM REJECTED %i -> %i\n",
+                src_d->domain_id, dst_d->domain_id);
+
+        put_domain(dst_d);
+
+        return ret;
+    }
+
     read_lock(&L1_global_argo_rwlock);
 
     if ( !src_d->argo )
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index 9abfd69..9ae69cc 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -732,6 +732,12 @@ static XSM_INLINE int xsm_argo_register_any_source(const struct domain *d)
     return 0;
 }
 
+static XSM_INLINE int xsm_argo_send(const struct domain *d,
+                                    const struct domain *t)
+{
+    return 0;
+}
+
 #endif /* CONFIG_ARGO */
 
 #include <public/version.h>
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index 0b40714..4211892 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -185,6 +185,7 @@ struct xsm_operations {
     int (*argo_register_single_source) (const struct domain *d,
                                         const struct domain *t);
     int (*argo_register_any_source) (const struct domain *d);
+    int (*argo_send) (const struct domain *d, const struct domain *t);
 #endif
 };
 
@@ -715,6 +716,11 @@ static inline int xsm_argo_register_any_source(const struct domain *d)
     return xsm_ops->argo_register_any_source(d);
 }
 
+static inline int xsm_argo_send(const struct domain *d, const struct domain *t)
+{
+    return xsm_ops->argo_send(d, t);
+}
+
 #endif /* CONFIG_ARGO */
 
 #endif /* XSM_NO_WRAPPERS */
diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
index ed236b0..ffac774 100644
--- a/xen/xsm/dummy.c
+++ b/xen/xsm/dummy.c
@@ -155,5 +155,6 @@ void __init xsm_fixup_ops (struct xsm_operations *ops)
 #ifdef CONFIG_ARGO
     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);
 #endif
 }
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index fcb7487..76c012c 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -1732,6 +1732,12 @@ static int flask_argo_register_any_source(const struct domain *d)
     return avc_has_perm(domain_sid(d), SECINITSID_XEN, SECCLASS_ARGO,
                         ARGO__REGISTER_ANY_SOURCE, NULL);
 }
+
+static int flask_argo_send(const struct domain *d, const struct domain *t)
+{
+    return domain_has_perm(d, t, SECCLASS_ARGO, ARGO__SEND);
+}
+
 #endif
 
 long do_flask_op(XEN_GUEST_HANDLE_PARAM(xsm_op_t) u_flask_op);
@@ -1871,6 +1877,7 @@ static struct xsm_operations flask_ops = {
 #ifdef CONFIG_ARGO
     .argo_register_single_source = flask_argo_register_single_source,
     .argo_register_any_source = flask_argo_register_any_source,
+    .argo_send = flask_argo_send,
 #endif
 };
 
diff --git a/xen/xsm/flask/policy/access_vectors b/xen/xsm/flask/policy/access_vectors
index fb95c97..f6c5377 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -541,4 +541,6 @@ class argo
     # Domain requesting registration of a communication ring
     # to receive messages from any other domain.
     register_any_source
+    # Domain sending a message to another domain.
+    send
 }
-- 
2.7.4


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