[Xen-devel] [PATCH 3/5] xsm/flask: clean interdomain event channel hook

[Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>]

Don't attempt to relabel the already-bound half of the event channel
pair created by an interdomain event channel. This relabeling also
performed an incorrect check that the destination domain is permitted to
create the reverse event channel, which may not be true if the unbound
channel was created by the domain builder (like the xenstore channel).

Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
 xen/xsm/flask/hooks.c |   30 ++++++++----------------------
 1 files changed, 8 insertions(+), 22 deletions(-)

diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 649c473..9948fca 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -182,12 +182,12 @@ static int flask_evtchn_unbound(struct domain *d1, struct 
evtchn *chn,
 static int flask_evtchn_interdomain(struct domain *d1, struct evtchn *chn1, 
                                     struct domain *d2, struct evtchn *chn2)
 {
-    u32 newsid1;
-    u32 newsid2;
+    u32 newsid;
     int rc;
-    struct domain_security_struct *dsec1, *dsec2;
+    struct domain_security_struct *dsec, *dsec1, *dsec2;
     struct evtchn_security_struct *esec1, *esec2;
 
+    dsec = current->domain->ssid;
     dsec1 = d1->ssid;
     dsec2 = d2->ssid;
 
@@ -195,7 +195,7 @@ static int flask_evtchn_interdomain(struct domain *d1, 
struct evtchn *chn1,
     esec2 = chn2->ssid;
 
     rc = security_transition_sid(dsec1->sid, dsec2->sid, 
-                                 SECCLASS_EVENT, &newsid1);
+                                 SECCLASS_EVENT, &newsid);
     if ( rc )
     {
         printk("%s: security_transition_sid failed, rc=%d (domain=%d)\n",
@@ -203,33 +203,19 @@ static int flask_evtchn_interdomain(struct domain *d1, 
struct evtchn *chn1,
         return rc;
     }
 
-    rc = avc_has_perm(dsec1->sid, newsid1, SECCLASS_EVENT, EVENT__CREATE, 
NULL);
-    if ( rc )
-        return rc;
-
-    rc = security_transition_sid(dsec2->sid, dsec1->sid, 
-                                 SECCLASS_EVENT, &newsid2);
+    rc = avc_has_perm(dsec->sid, newsid, SECCLASS_EVENT, EVENT__CREATE, NULL);
     if ( rc )
-    {
-        printk("%s: security_transition_sid failed, rc=%d (domain=%d)\n",
-               __FUNCTION__, -rc, d1->domain_id);
         return rc;
-    }
 
-    rc = avc_has_perm(dsec2->sid, newsid2, SECCLASS_EVENT, EVENT__CREATE, 
NULL);
+    rc = avc_has_perm(newsid, dsec2->sid, SECCLASS_EVENT, EVENT__BIND, NULL);
     if ( rc )
         return rc;
 
-    rc = avc_has_perm(newsid1, dsec2->sid, SECCLASS_EVENT, EVENT__BIND, NULL);
+    rc = avc_has_perm(esec2->sid, dsec1->sid, SECCLASS_EVENT, EVENT__BIND, 
NULL);
     if ( rc )
         return rc;
 
-    rc = avc_has_perm(newsid2, dsec1->sid, SECCLASS_EVENT, EVENT__BIND, NULL);
-    if ( rc )
-        return rc;    
-
-    esec1->sid = newsid1;
-    esec2->sid = newsid2;
+    esec1->sid = newsid;
 
     return rc;
 }
-- 
1.7.7.6


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel