[src/trunk]: src/sys/kern Fix kernel info leak. There are 4 bytes of padding ...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f0f974ddea3a
branches:  trunk
changeset: 836928:f0f974ddea3a
user:      maxv <maxv%NetBSD.org@localhost>
date:      Tue Nov 13 06:58:14 2018 +0000

description:
Fix kernel info leak. There are 4 bytes of padding in struct kevent.

[  287.537676] kleak: Possible leak in copyout: [len=40, leaked=4]
[  287.537676] #0 0xffffffff80b7c41a in kleak_note <netbsd>
[  287.547673] #1 0xffffffff80b7c49a in kleak_copyout <netbsd>
[  287.557677] #2 0xffffffff80b1d32d in kqueue_scan.isra.1.constprop.2 <netbsd>
[  287.557677] #3 0xffffffff80b1dc6a in kevent1 <netbsd>
[  287.567683] #4 0xffffffff80b1dcb0 in sys___kevent50 <netbsd>
[  287.567683] #5 0xffffffff8025ab3c in sy_call <netbsd>
[  287.577688] #6 0xffffffff8025ad6e in sy_invoke <netbsd>
[  287.587693] #7 0xffffffff8025adf4 in syscall <netbsd>

diffstat:

 sys/kern/kern_event.c |  5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diffs (26 lines):

diff -r 3012a77604cc -r f0f974ddea3a sys/kern/kern_event.c
--- a/sys/kern/kern_event.c     Tue Nov 13 06:57:14 2018 +0000
+++ b/sys/kern/kern_event.c     Tue Nov 13 06:58:14 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_event.c,v 1.103 2018/01/12 17:58:51 christos Exp $        */
+/*     $NetBSD: kern_event.c,v 1.104 2018/11/13 06:58:14 maxv Exp $    */
 
 /*-
  * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
@@ -58,7 +58,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_event.c,v 1.103 2018/01/12 17:58:51 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_event.c,v 1.104 2018/11/13 06:58:14 maxv Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -632,6 +632,7 @@
                 * event with the parent's pid.  Register knote with new
                 * process.
                 */
+               memset(&kev, 0, sizeof(kev));
                kev.ident = hint & NOTE_PDATAMASK;      /* pid */
                kev.filter = kn->kn_filter;
                kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1;