CVS commit: src/sys/kern

[Taylor R Campbell]

Module Name:    src
Committed By:   riastradh
Date:           Wed Jul  6 01:13:06 UTC 2022

Modified Files:
        src/sys/kern: vfs_vnops.c

Log Message:
mmap(2): Avoid overflow in overflow check in vn_mmap.


To generate a diff of this commit:
cvs rdiff -u -r1.229 -r1.230 src/sys/kern/vfs_vnops.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.


Modified files:

Index: src/sys/kern/vfs_vnops.c
diff -u src/sys/kern/vfs_vnops.c:1.229 src/sys/kern/vfs_vnops.c:1.230
--- src/sys/kern/vfs_vnops.c:1.229	Wed Jul  6 01:12:46 2022
+++ src/sys/kern/vfs_vnops.c	Wed Jul  6 01:13:06 2022
@@ -1,4 +1,4 @@
-/*	$NetBSD: vfs_vnops.c,v 1.229 2022/07/06 01:12:46 riastradh Exp $	*/
+/*	$NetBSD: vfs_vnops.c,v 1.230 2022/07/06 01:13:06 riastradh Exp $	*/
 
 /*-
  * Copyright (c) 2009 The NetBSD Foundation, Inc.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnops.c,v 1.229 2022/07/06 01:12:46 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnops.c,v 1.230 2022/07/06 01:13:06 riastradh Exp $");
 
 #include "veriexec.h"
 
@@ -930,7 +930,8 @@ vn_mmap(struct file *fp, off_t *offp, si
 	if (vp->v_type != VCHR && off < 0) {
 		return EINVAL;
 	}
-	if (vp->v_type != VCHR && (off_t)(off + size) < off) {
+	if (vp->v_type != VCHR &&
+	    (size > __type_max(off_t) || off > __type_max(off_t) - size)) {
 		/* no offset wrapping */
 		return EOVERFLOW;
 	}