[PATCH v2] ramdac: Check sPriv != NULL in xf86CheckHWCursor()

[Alex Goins]

xf86CheckHWCursor() would dereference sPriv without NULL checking it. If Option
"SWCursor" is specified, sPriv == NULL. In this case we should assume that HW
cursors are not supported.

Signed-off-by: Alex Goins <agoins at nvidia.com>
Reviewed-by: Andy Ritger <aritger at nvidia.com>
---
 hw/xfree86/ramdac/xf86HWCurs.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/xfree86/ramdac/xf86HWCurs.c b/hw/xfree86/ramdac/xf86HWCurs.c
index da2b181..4481320 100644
--- a/hw/xfree86/ramdac/xf86HWCurs.c
+++ b/hw/xfree86/ramdac/xf86HWCurs.c
@@ -148,6 +148,10 @@ xf86CheckHWCursor(ScreenPtr pScreen, CursorPtr cursor, xf86CursorInfoPtr infoPtr
             continue;
 
         sPriv = dixLookupPrivate(&pSlave->devPrivates, xf86CursorScreenKey);
+        if (!sPriv) /* NULL if Option "SWCursor", possibly other conditions */
+            return FALSE;
+
+        /* FALSE if HWCursor not supported by slave */
         if (!xf86ScreenCheckHWCursor(pSlave, cursor, sPriv->CursorInfoPtr))
             return FALSE;
     }
-- 
1.9.1