[PATCH 4/5] ramfb: add sanity checks to ramfb_create_display_surface

[Gerd Hoffmann <kraxel@redhat.com>]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/display/ramfb.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/display/ramfb.c b/hw/display/ramfb.c
index fbe959147dc9..d1b1cb9bb294 100644
--- a/hw/display/ramfb.c
+++ b/hw/display/ramfb.c
@@ -15,6 +15,7 @@
 #include "qapi/error.h"
 #include "hw/loader.h"
 #include "hw/display/ramfb.h"
+#include "hw/display/bochs-vbe.h" /* for limits */
 #include "ui/console.h"
 #include "sysemu/reset.h"
 
@@ -49,6 +50,11 @@ static DisplaySurface *ramfb_create_display_surface(int width, int height,
     hwaddr size;
     void *data;
 
+    if (width < 16 || width > VBE_DISPI_MAX_XRES ||
+        height < 16 || height > VBE_DISPI_MAX_YRES ||
+        format == 0 /* unknown format */)
+        return NULL;
+
     if (linesize == 0) {
         linesize = width * PIXMAN_FORMAT_BPP(format) / 8;
     }
-- 
2.18.2