passthrough/stubdom: clean up hypercall privilege checking

This patch adds securty checks for pci passthrough related hypercalls
to enforce that the current domain owns the resources that it is about
to remap. It also adds a call to xc_assign_device to xend and removes
the PRIVILEGED_STUBDOMS flags.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

8 files changed, 40 insertions, 21 deletions

diff --git a/Config.mk b/Config.mk
index 79029a0be9..63ae38c7b6 100644
--- a/Config.mk
+++ b/Config.mk
@@ -150,9 +150,9 @@ QEMU_REMOTE=http://xenbits.xensource.com/git-http/qemu-xen-unstable.git
 # CONFIG_QEMU ?= ../qemu-xen.git
 CONFIG_QEMU ?= $(QEMU_REMOTE)
 
-QEMU_TAG ?= a3285ff385d2568f0226f15fee2b9808ec3b6deb
-# Tue Oct 20 15:16:34 2009 +0100
-# usb hotplug in qemu-dm via xm
+QEMU_TAG ?= b4bb8b3f09d1c873f522f6aebe1f125a6d1854d0
+# Wed Oct 21 16:42:15 2009 +0100
+# passthrough: fix security issue with stubdoms
 
 OCAML_XENSTORED_REPO=http://xenbits.xensource.com/ext/xen-ocaml-tools.hg
 
diff --git a/tools/python/xen/xend/server/pciif.py b/tools/python/xen/xend/server/pciif.py
index 0e54ae14df..06b2ec9310 100644
--- a/tools/python/xen/xend/server/pciif.py
+++ b/tools/python/xen/xend/server/pciif.py
@@ -444,7 +444,15 @@ class PciController(DevController):
         # For hvm guest, (from c/s 19679 on) assigning device statically and
         # dynamically both go through reconfigureDevice(), so HERE the
         # setupOneDevice() is not necessary.
-        if not self.vm.info.is_hvm():
+        if self.vm.info.is_hvm():
+            for pci_dev in pci_dev_list:
+                # Setup IOMMU device assignment
+                bdf = xc.assign_device(self.getDomid(), pci_dict_to_xc_str(pci_dev))
+                pci_str = pci_dict_to_bdf_str(pci_dev)
+                if bdf > 0:
+                    raise VmError("Failed to assign device to IOMMU (%s)" % pci_str)
+                log.debug("pci: assign device %s" % pci_str)
+        else :
             for d in pci_dev_list:
                 self.setupOneDevice(d)
         wPath = '/local/domain/0/backend/pci/%u/0/aerState' % (self.getDomid())
diff --git a/xen/Rules.mk b/xen/Rules.mk
index 731e0cc88c..10847182ae 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -11,9 +11,6 @@ crash_debug   ?= n
 gdbsx         ?= n
 frame_pointer ?= n
 
-# Allow some delicate passthrough related hypercalls to be made from a stubdom
-privileged_stubdoms ?= y
-
 XEN_ROOT=$(BASEDIR)/..
 include $(XEN_ROOT)/Config.mk
 
@@ -56,7 +53,6 @@ CFLAGS-$(perfc)         += -DPERF_COUNTERS
 CFLAGS-$(perfc_arrays)  += -DPERF_ARRAYS
 CFLAGS-$(lock_profile)  += -DLOCK_PROFILE
 CFLAGS-$(frame_pointer) += -fno-omit-frame-pointer -DCONFIG_FRAME_POINTER
-CFLAGS-$(privileged_stubdoms) += -DPRIVILEGED_STUBDOMS
 CFLAGS-$(gdbsx)         += -DXEN_GDBSX_CONFIG
 
 ifneq ($(max_phys_cpus),)
diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 581fcb3295..52f3945f06 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -796,6 +796,11 @@ long arch_do_domctl(
         if ( ret )
             goto bind_out;
 
+        ret = -EPERM;
+        if ( !IS_PRIV(current->domain) &&
+             !irq_access_permitted(current->domain, bind->machine_irq) )
+            goto bind_out;
+
         ret = -ESRCH;
         if ( iommu_enabled )
         {
@@ -820,6 +825,12 @@ long arch_do_domctl(
         if ( (d = rcu_lock_domain_by_id(domctl->domain)) == NULL )
             break;
         bind = &(domctl->u.bind_pt_irq);
+
+        ret = -EPERM;
+        if ( !IS_PRIV(current->domain) &&
+             !irq_access_permitted(current->domain, bind->machine_irq) )
+            goto bind_out;
+
         if ( iommu_enabled )
         {
             spin_lock(&pcidevs_lock);
@@ -848,6 +859,11 @@ long arch_do_domctl(
         if ( unlikely((d = rcu_lock_domain_by_id(domctl->domain)) == NULL) )
             break;
 
+        ret = -EPERM;
+        if ( !IS_PRIV(current->domain) &&
+             !iomem_access_permitted(current->domain, mfn, mfn + nr_mfns - 1) )
+            break;
+
         ret=0;
         if ( domctl->u.memory_mapping.add_mapping )
         {
@@ -895,6 +911,11 @@ long arch_do_domctl(
             break;
         }
 
+        ret = -EPERM;
+        if ( !IS_PRIV(current->domain) &&
+             !ioports_access_permitted(current->domain, fmp, fmp + np - 1) )
+            break;
+
         ret = -ESRCH;
         if ( unlikely((d = rcu_lock_domain_by_id(domctl->domain)) == NULL) )
             break;
diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index 510be8db12..74d096f462 100644
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -1343,7 +1343,9 @@ int map_domain_pirq(
     ASSERT(spin_is_locked(&pcidevs_lock));
     ASSERT(spin_is_locked(&d->event_lock));
 
-    if ( !STUBDOM_IS_PRIV_FOR(current->domain, d) )
+    if ( !IS_PRIV(current->domain) &&
+         !(IS_PRIV_FOR(current->domain, d) &&
+          irq_access_permitted(current->domain, pirq)))
         return -EPERM;
 
     if ( pirq < 0 || pirq >= d->nr_pirqs || irq < 0 || irq >= nr_irqs )
diff --git a/xen/arch/x86/physdev.c b/xen/arch/x86/physdev.c
index 0c284e84bc..2d65fa4df4 100644
--- a/xen/arch/x86/physdev.c
+++ b/xen/arch/x86/physdev.c
@@ -45,7 +45,7 @@ static int physdev_map_pirq(struct physdev_map_pirq *map)
     if ( d == NULL )
         return -ESRCH;
 
-    if ( !STUBDOM_IS_PRIV_FOR(current->domain, d) )
+    if ( !IS_PRIV_FOR(current->domain, d) )
     {
         ret = -EPERM;
         goto free_domain;
@@ -169,7 +169,7 @@ static int physdev_unmap_pirq(struct physdev_unmap_pirq *unmap)
         return -ESRCH;
 
     ret = -EPERM;
-    if ( !STUBDOM_IS_PRIV_FOR(current->domain, d) )
+    if ( !IS_PRIV_FOR(current->domain, d) )
         goto free_domain;
 
     spin_lock(&pcidevs_lock);
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 0b9ad758dd..290b9494dd 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -231,14 +231,12 @@ long do_domctl(XEN_GUEST_HANDLE(xen_domctl_t) u_domctl)
     case XEN_DOMCTL_ioport_mapping:
     case XEN_DOMCTL_memory_mapping:
     case XEN_DOMCTL_bind_pt_irq:
-    case XEN_DOMCTL_unbind_pt_irq:
-    case XEN_DOMCTL_assign_device:
-    case XEN_DOMCTL_deassign_device: {
+    case XEN_DOMCTL_unbind_pt_irq: {
         struct domain *d;
         bool_t is_priv = IS_PRIV(current->domain);
         if ( !is_priv && ((d = rcu_lock_domain_by_id(op->domain)) != NULL) )
         {
-            is_priv = STUBDOM_IS_PRIV_FOR(current->domain, d);
+            is_priv = IS_PRIV_FOR(current->domain, d);
             rcu_unlock_domain(d);
         }
         if ( !is_priv )
diff --git a/xen/include/xen/config.h b/xen/include/xen/config.h
index 43d6bc6cff..7872f13e8d 100644
--- a/xen/include/xen/config.h
+++ b/xen/include/xen/config.h
@@ -95,10 +95,4 @@ int current_domain_id(void);
 #define __cpuinitdata
 #define __cpuinit
 
-#ifdef PRIVILEGED_STUBDOMS
-#define STUBDOM_IS_PRIV_FOR(x,y) IS_PRIV_FOR(x,y)
-#else
-#define STUBDOM_IS_PRIV_FOR(x,y) IS_PRIV(x)
-#endif
-
 #endif /* __XEN_CONFIG_H__ */