test against [VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS] in access_ok()

ok kettenis@

1 files changed, 8 insertions, 3 deletions

diff --git a/sys/dev/pci/drm/include/linux/uaccess.h b/sys/dev/pci/drm/include/linux/uaccess.h
index 765a0546caf..99ef746cc4a 100644
--- a/sys/dev/pci/drm/include/linux/uaccess.h
+++ b/sys/dev/pci/drm/include/linux/uaccess.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uaccess.h,v 1.4 2020/11/17 11:20:59 jsg Exp $	*/
+/*	$OpenBSD: uaccess.h,v 1.5 2020/12/20 03:42:01 jsg Exp $	*/
 /*
  * Copyright (c) 2015 Mark Kettenis
  *
@@ -18,8 +18,10 @@
 #ifndef _LINUX_UACCESS_H
 #define _LINUX_UACCESS_H
 
-#include <sys/types.h>
+#include <sys/param.h>
 #include <sys/systm.h>
+#include <uvm/uvm_extern.h>
+
 #include <linux/sched.h>
 
 static inline unsigned long
@@ -67,7 +69,10 @@ copy_from_user(void *to, const void *from, unsigned len)
 static inline int
 access_ok(const void *addr, unsigned long size)
 {
-	return 1;
+	vaddr_t startva = (vaddr_t)addr;
+	vaddr_t endva = ((vaddr_t)addr) + size;
+	return (startva >= VM_MIN_ADDRESS && endva >= VM_MIN_ADDRESS) &&
+	    (startva <= VM_MAXUSER_ADDRESS && endva <= VM_MAXUSER_ADDRESS);
 }
 
 #define user_access_begin(addr, size)	access_ok(addr, size)