vmware-vga: add vmsvga_verify_rect

Add verification function for rectangles, returning
true if verification passes and false otherwise.

Cc: qemu-stable@nongnu.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Don Koch <dkoch@verizon.com>
(cherry picked from commit 0725890)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

hw/display/vmware_vga.c

@@ -294,8 +294,59 @@ enum {
     SVGA_CURSOR_ON_RESTORE_TO_FB = 3,
 };
 
+static inline bool vmsvga_verify_rect(DisplaySurface *surface,
+                                      const char *name,
+                                      int x, int y, int w, int h)
+{
+    if (x < 0) {
+        fprintf(stderr, "%s: x was < 0 (%d)\n", name, x);
+        return false;
+    }
+    if (x > SVGA_MAX_WIDTH) {
+        fprintf(stderr, "%s: x was > %d (%d)\n", name, SVGA_MAX_WIDTH, x);
+        return false;
+    }
+    if (w < 0) {
+        fprintf(stderr, "%s: w was < 0 (%d)\n", name, w);
+        return false;
+    }
+    if (w > SVGA_MAX_WIDTH) {
+        fprintf(stderr, "%s: w was > %d (%d)\n", name, SVGA_MAX_WIDTH, w);
+        return false;
+    }
+    if (x + w > surface_width(surface)) {
+        fprintf(stderr, "%s: width was > %d (x: %d, w: %d)\n",
+                name, surface_width(surface), x, w);
+        return false;
+    }
+
+    if (y < 0) {
+        fprintf(stderr, "%s: y was < 0 (%d)\n", name, y);
+        return false;
+    }
+    if (y > SVGA_MAX_HEIGHT) {
+        fprintf(stderr, "%s: y was > %d (%d)\n", name, SVGA_MAX_HEIGHT, y);
+        return false;
+    }
+    if (h < 0) {
+        fprintf(stderr, "%s: h was < 0 (%d)\n", name, h);
+        return false;
+    }
+    if (h > SVGA_MAX_HEIGHT) {
+        fprintf(stderr, "%s: h was > %d (%d)\n", name, SVGA_MAX_HEIGHT, h);
+        return false;
+    }
+    if (y + h > surface_height(surface)) {
+        fprintf(stderr, "%s: update height > %d (y: %d, h: %d)\n",
+                name, surface_height(surface), y, h);
+        return false;
+    }
+
+    return true;
+}
+
 static inline void vmsvga_update_rect(struct vmsvga_state_s *s,
-                int x, int y, int w, int h)
+                                      int x, int y, int w, int h)
 {
     DisplaySurface *surface = qemu_console_surface(s->vga.con);
     int line;