1 files changed, 51 insertions, 0 deletions
diff --git a/system/xen/xsa/xsa334.patch b/system/xen/xsa/xsa334.patch
new file mode 100644
index 0000000000000..4260cdb2b2db8
--- /dev/null
+++ b/system/xen/xsa/xsa334.patch
@@ -0,0 +1,51 @@
+From: Andrew Cooper <andrew.cooper3@citrix.com>
+Subject: xen/memory: Don't skip the RCU unlock path in acquire_resource()
+
+In the case that an HVM Stubdomain makes an XENMEM_acquire_resource hypercall,
+the FIXME path will bypass rcu_unlock_domain() on the way out of the function.
+
+Move the check to the start of the function.  This does change the behaviour
+of the get-size path for HVM Stubdomains, but that functionality is currently
+broken and unused anyway, as well as being quite useless to entities which
+can't actually map the resource anyway.
+
+This is XSA-334.
+
+Fixes: 83fa6552ce ("common: add a new mappable resource type: XENMEM_resource_grant_table")
+Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
+Reviewed-by: Jan Beulich <jbeulich@suse.com>
+
+diff --git a/xen/common/memory.c b/xen/common/memory.c
+index 1a3c9ffb30..29741d8904 100644
+--- a/xen/common/memory.c
++++ b/xen/common/memory.c
+@@ -1058,6 +1058,14 @@ static int acquire_resource(
+     xen_pfn_t mfn_list[32];
+     int rc;
+ 
++    /*
++     * FIXME: Until foreign pages inserted into the P2M are properly
++     *        reference counted, it is unsafe to allow mapping of
++     *        resource pages unless the caller is the hardware domain.
++     */
++    if ( paging_mode_translate(currd) && !is_hardware_domain(currd) )
++        return -EACCES;
++
+     if ( copy_from_guest(&xmar, arg, 1) )
+         return -EFAULT;
+ 
+@@ -1114,14 +1122,6 @@ static int acquire_resource(
+         xen_pfn_t gfn_list[ARRAY_SIZE(mfn_list)];
+         unsigned int i;
+ 
+-        /*
+-         * FIXME: Until foreign pages inserted into the P2M are properly
+-         *        reference counted, it is unsafe to allow mapping of
+-         *        resource pages unless the caller is the hardware domain.
+-         */
+-        if ( !is_hardware_domain(currd) )
+-            return -EACCES;
+-
+         if ( copy_from_guest(gfn_list, xmar.frame_list, xmar.nr_frames) )
+             rc = -EFAULT;
+