[Xen-changelog] [xen stable-4.2] x86/mem_event: validate the response vcpu_id before acting on it

[patchbot@xxxxxxx]

commit b1d8b364c5e90295263d77f0da14127d4197b585
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Mon Jul 28 15:15:21 2014 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Jul 28 15:15:21 2014 +0200

    x86/mem_event: validate the response vcpu_id before acting on it
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Tim Deegan <tim@xxxxxxx>
    Reviewed-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>
    Tested-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
    master commit: ee75480b3c8856db9ef1aa45418f35ec0d78989d
    master date: 2014-07-23 18:07:11 +0200
---
 xen/arch/x86/mm/mem_sharing.c |   11 ++++++++++-
 xen/arch/x86/mm/p2m.c         |   22 ++++++++++++++++++++--
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index 09703a1..f04034d 100644
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -595,11 +595,20 @@ int mem_sharing_sharing_resume(struct domain *d)
     /* Get all requests off the ring */
     while ( mem_event_get_response(d, &d->mem_event->share, &rsp) )
     {
+        struct vcpu *v;
+
         if ( rsp.flags & MEM_EVENT_FLAG_DUMMY )
             continue;
+
+        /* Validate the vcpu_id in the response. */
+        if ( (rsp.vcpu_id >= d->max_vcpus) || !d->vcpu[rsp.vcpu_id] )
+            continue;
+
+        v = d->vcpu[rsp.vcpu_id];
+
         /* Unpause domain/vcpu */
         if ( rsp.flags & MEM_EVENT_FLAG_VCPU_PAUSED )
-            vcpu_unpause(d->vcpu[rsp.vcpu_id]);
+            vcpu_unpause(v);
     }
 
     return 0;
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index afc6319..1619a79 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -1211,8 +1211,17 @@ void p2m_mem_paging_resume(struct domain *d)
     /* Pull all responses off the ring */
     while( mem_event_get_response(d, &d->mem_event->paging, &rsp) )
     {
+        struct vcpu *v;
+
         if ( rsp.flags & MEM_EVENT_FLAG_DUMMY )
             continue;
+
+        /* Validate the vcpu_id in the response. */
+        if ( (rsp.vcpu_id >= d->max_vcpus) || !d->vcpu[rsp.vcpu_id] )
+            continue;
+
+        v = d->vcpu[rsp.vcpu_id];
+
         /* Fix p2m entry if the page was not dropped */
         if ( !(rsp.flags & MEM_EVENT_FLAG_DROP_PAGE) )
         {
@@ -1231,7 +1240,7 @@ void p2m_mem_paging_resume(struct domain *d)
         }
         /* Unpause domain */
         if ( rsp.flags & MEM_EVENT_FLAG_VCPU_PAUSED )
-            vcpu_unpause(d->vcpu[rsp.vcpu_id]);
+            vcpu_unpause(v);
     }
 }
 
@@ -1328,11 +1337,20 @@ void p2m_mem_access_resume(struct domain *d)
     /* Pull all responses off the ring */
     while( mem_event_get_response(d, &d->mem_event->access, &rsp) )
     {
+        struct vcpu *v;
+
         if ( rsp.flags & MEM_EVENT_FLAG_DUMMY )
             continue;
+
+        /* Validate the vcpu_id in the response. */
+        if ( (rsp.vcpu_id >= d->max_vcpus) || !d->vcpu[rsp.vcpu_id] )
+            continue;
+
+        v = d->vcpu[rsp.vcpu_id];
+
         /* Unpause domain */
         if ( rsp.flags & MEM_EVENT_FLAG_VCPU_PAUSED )
-            vcpu_unpause(d->vcpu[rsp.vcpu_id]);
+            vcpu_unpause(v);
     }
 }
 
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.2

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