[PATCH] Xi: don't crash when deleting invalid device properties.

[Peter Hutterer]

Deleting a property that was not set on a device leads to a null-pointer
dereference. The protocol allows deleting those properties - it has to be a
noop.

Reproducible:
xinput --set-prop "My device" --type=int --format=8 "my property" 1
xinput --delete-prop "My other device" "my property"

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 Xi/xiproperty.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/Xi/xiproperty.c b/Xi/xiproperty.c
index 024dc44..53c947f 100644
--- a/Xi/xiproperty.c
+++ b/Xi/xiproperty.c
@@ -643,6 +643,9 @@ XIDeleteDeviceProperty (DeviceIntPtr device, Atom property, Bool fromClient)
         if (prop->propertyName == property)
             break;
 
+    if (!prop)
+        return BadAtom;
+
     if (fromClient && !prop->deletable)
         return BadAccess;
 
@@ -934,6 +937,10 @@ ProcXDeleteDeviceProperty (ClientPtr client)
     }
 
     rc = XIDeleteDeviceProperty(dev, stuff->property, TRUE);
+    /* if the property doesn't exist on this device, it's a noop */
+    if (rc == BadAtom)
+        rc = Success;
+
     return rc;
 }
 
@@ -1177,6 +1184,10 @@ ProcXIDeleteProperty(ClientPtr client)
     }
 
     rc = XIDeleteDeviceProperty(dev, stuff->property, TRUE);
+    /* if the property doesn't exist on this device, it's a noop */
+    if (rc == BadAtom)
+        rc = Success;
+
     return rc;
 }
 
-- 
1.6.5.2