From: Jan Beulich <jbeulich@suse.com>
Date: Fri, 2 Dec 2022 09:25:59 +0000 (+0100)
Subject: gnttab: bail from GFN-storing loops early in case of error
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=5488cc3a4d7caa75259cdeb5f5b9da227fc12360;p=people%2Fdwmw2%2Fxen.git

gnttab: bail from GFN-storing loops early in case of error

The contents of the output arrays are undefined anyway when the
operation itself gets marked as failed. There's no value in trying to
continue after a guest memory access failure.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---

diff --git a/xen/common/compat/grant_table.c b/xen/common/compat/grant_table.c
index 4f6d0b05fb..744f9b6e3d 100644
--- a/xen/common/compat/grant_table.c
+++ b/xen/common/compat/grant_table.c
@@ -179,7 +179,10 @@ int compat_grant_table_op(
                             unsigned int frame = (_s_)->frame_list.p[i]; \
                             if ( __copy_to_compat_offset((_d_)->frame_list, \
                                                          i, &frame, 1) ) \
+                            { \
                                 (_s_)->status = GNTST_bad_virt_addr; \
+                                break; \
+                            } \
                         } \
                     } \
                 } while (0)
diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index 6326bae5aa..fa28c3cb7b 100644
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -2101,7 +2101,10 @@ gnttab_setup_table(
         BUG_ON(SHARED_M2P(gmfn));
 
         if ( __copy_to_guest_offset(op.frame_list, i, &gmfn, 1) )
+        {
             op.status = GNTST_bad_virt_addr;
+            break;
+        }
     }
 
  unlock:
@@ -3311,7 +3314,10 @@ gnttab_get_status_frames(XEN_GUEST_HANDLE_PARAM(gnttab_get_status_frames_t) uop,
     {
         gmfn = gfn_x(gnttab_status_gfn(d, gt, i));
         if ( __copy_to_guest_offset(op.frame_list, i, &gmfn, 1) )
+        {
             op.status = GNTST_bad_virt_addr;
+            break;
+        }
     }
 
  unlock: