[PATCH 4/9] xen/arch/x86: remove IS_PRIV_FOR references

Daniel De Graaf
Thu, 11 Apr 2013 20:13:35 -0000

The check in guest_physmap_mark_populate_on_demand is redundant, since
its only caller is populate_physmap whose only caller checks the
xsm_memory_adjust_reservation hook prior to calling.

Add a new XSM hook for the other two checks since they allow privileged
domains to arbitrarily map a guest''s memory.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Cc: Keir Fraser <keir@xen.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Tim Deegan <tim@xen.org>
---
 xen/arch/x86/mm.c                   |  2 +-
 xen/arch/x86/mm/p2m-pod.c           |  3 ---
 xen/arch/x86/mm/shadow/multi.c      | 19 +++++++++++--------
 xen/include/xsm/dummy.h             |  6 ++++++
 xen/include/xsm/xsm.h               |  6 ++++++
 xen/xsm/dummy.c                     |  1 +
 xen/xsm/flask/hooks.c               |  6 ++++++
 xen/xsm/flask/policy/access_vectors |  3 +++
 8 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 58e1402..0cd4203 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -815,7 +815,7 @@ get_page_from_l1e(
          * minor hack can go away.
          */
         if ( (real_pg_owner == NULL) || (pg_owner == l1e_owner) ||
-             !IS_PRIV_FOR(pg_owner, real_pg_owner) )
+             xsm_priv_mapping(XSM_TARGET, pg_owner, real_pg_owner) )
         {
             MEM_LOG("pg_owner %d l1e_owner %d, but real_pg_owner %d",
                     pg_owner->domain_id, l1e_owner->domain_id,
diff --git a/xen/arch/x86/mm/p2m-pod.c b/xen/arch/x86/mm/p2m-pod.c
index 55936c6..04ffbcb 100644
--- a/xen/arch/x86/mm/p2m-pod.c
+++ b/xen/arch/x86/mm/p2m-pod.c
@@ -1117,9 +1117,6 @@ guest_physmap_mark_populate_on_demand(struct domain *d,
unsigned long gfn,
     mfn_t omfn;
     int rc = 0;

-    if ( !IS_PRIV_FOR(current->domain, d) )
-        return -EPERM;
-
     if ( !paging_mode_translate(d) )
         return -EINVAL;

diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index a593f76..a8ef75e 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -29,6 +29,7 @@
 #include <xen/perfc.h>
 #include <xen/domain_page.h>
 #include <xen/iocap.h>
+#include <xsm/xsm.h>
 #include <asm/page.h>
 #include <asm/current.h>
 #include <asm/shadow.h>
@@ -849,14 +850,16 @@ shadow_get_page_from_l1e(shadow_l1e_t sl1e, struct domain
*d, p2m_type_t type)
          !shadow_mode_translate(d) &&
          mfn_valid(mfn = shadow_l1e_get_mfn(sl1e)) &&
          (owner = page_get_owner(mfn_to_page(mfn))) &&
-         (d != owner) &&
-         IS_PRIV_FOR(d, owner))
-    {
-        res = get_page_from_l1e(sl1e, d, owner);
-        SHADOW_PRINTK("privileged domain %d installs map of mfn %05lx
"
-                       "which is owned by domain %d: %s\n",
-                       d->domain_id, mfn_x(mfn), owner->domain_id,
-                       res >= 0 ? "success" : "failed");
+         (d != owner) )
+    {
+        res = xsm_priv_mapping(XSM_TARGET, d, owner);
+        if ( !res ) {
+            res = get_page_from_l1e(sl1e, d, owner);
+            SHADOW_PRINTK("privileged domain %d installs map of mfn %05lx
"
+                           "which is owned by domain %d: %s\n",
+                           d->domain_id, mfn_x(mfn), owner->domain_id,
+                           res >= 0 ? "success" :
"failed");
+        }
     }

     /* Okay, it might still be a grant mapping PTE.  Try it. */
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index d53132b..9bfe596 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -586,6 +586,12 @@ static XSM_INLINE int xsm_update_va_mapping(XSM_DEFAULT_ARG
struct domain *d, st
     return xsm_default_action(action, d, f);
 }

+static XSM_INLINE int xsm_priv_mapping(XSM_DEFAULT_ARG struct domain *d, struct
domain *t)
+{
+    XSM_ASSERT_ACTION(XSM_TARGET);
+    return xsm_default_action(action, d, t);
+}
+
 static XSM_INLINE int xsm_bind_pt_irq(XSM_DEFAULT_ARG struct domain *d, struct
xen_domctl_bind_pt_irq *bind)
 {
     XSM_ASSERT_ACTION(XSM_HOOK);
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index b4065ad..69fe64a 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -156,6 +156,7 @@ struct xsm_operations {
                        struct domain *f, uint32_t flags);
     int (*mmuext_op) (struct domain *d, struct domain *f);
     int (*update_va_mapping) (struct domain *d, struct domain *f, l1_pgentry_t
pte);
+    int (*priv_mapping) (struct domain *d, struct domain *t);
     int (*bind_pt_irq) (struct domain *d, struct xen_domctl_bind_pt_irq *bind);
     int (*unbind_pt_irq) (struct domain *d, struct xen_domctl_bind_pt_irq
*bind);
     int (*ioport_permission) (struct domain *d, uint32_t s, uint32_t e, uint8_t
allow);
@@ -594,6 +595,11 @@ static inline int xsm_update_va_mapping(xsm_default_t def,
struct domain *d, str
     return xsm_ops->update_va_mapping(d, f, pte);
 }

+static inline int xsm_priv_mapping(xsm_default_t def, struct domain *d, struct
domain *t)
+{
+    return xsm_ops->priv_mapping(d, t);
+}
+
 static inline int xsm_bind_pt_irq(xsm_default_t def, struct domain *d,
                                                 struct xen_domctl_bind_pt_irq
*bind)
 {
diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
index f769642..3d84e73 100644
--- a/xen/xsm/dummy.c
+++ b/xen/xsm/dummy.c
@@ -126,6 +126,7 @@ void xsm_fixup_ops (struct xsm_operations *ops)
     set_to_dummy_if_null(ops, mmu_update);
     set_to_dummy_if_null(ops, mmuext_op);
     set_to_dummy_if_null(ops, update_va_mapping);
+    set_to_dummy_if_null(ops, priv_mapping);
     set_to_dummy_if_null(ops, bind_pt_irq);
     set_to_dummy_if_null(ops, unbind_pt_irq);
     set_to_dummy_if_null(ops, ioport_permission);
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 78f0b92..809e0f9 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -1354,6 +1354,11 @@ static int flask_update_va_mapping(struct domain *d,
struct domain *f,
     return domain_has_perm(d, f, SECCLASS_MMU, map_perms);
 }

+static int flask_priv_mapping(struct domain *d, struct domain *t)
+{
+    return domain_has_perm(d, t, SECCLASS_MMU, MMU__TARGET_HACK);
+}
+
 static int flask_get_device_group(uint32_t machine_bdf)
 {
     u32 rsid;
@@ -1545,6 +1550,7 @@ static struct xsm_operations flask_ops = {
     .mmu_update = flask_mmu_update,
     .mmuext_op = flask_mmuext_op,
     .update_va_mapping = flask_update_va_mapping,
+    .priv_mapping = flask_priv_mapping,
     .get_device_group = flask_get_device_group,
     .test_assign_device = flask_test_assign_device,
     .assign_device = flask_assign_device,
diff --git a/xen/xsm/flask/policy/access_vectors
b/xen/xsm/flask/policy/access_vectors
index 176235c..63ee4dd 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -330,6 +330,9 @@ class mmu
 #  source = domain making the hypercall
 #  target = domain whose pages are being exchanged
     exchange
+# Allow a privileged domain to install a map of a page it does not own.  Used
+# for stub domain device models with the PV framebuffer.
+    target_hack
 }

 # control of the paging_domctl split by subop
--
1.8.1.4