[src/trunk]: src/sys/kern Fix kernel info leak, 4 bytes of padding in struct ...

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

details:   https://anonhg.NetBSD.org/src/rev/c24eac122418
branches:  trunk
changeset: 995002:c24eac122418
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sat Dec 01 14:05:33 2018 +0000

description:
Fix kernel info leak, 4 bytes of padding in struct _ksiginfo. Maybe we
should just set _pad to zero on LP64?

        + Possible info leak: [len=40, leaked=4]
        | #0 0xffffffff80baf397 in kleak_copyout
        | #1 0xffffffff80bda817 in sigtimedwait1
        | #2 0xffffffff80bdab95 in sys_____sigtimedwait50
        | #3 0xffffffff80259c42 in syscall

diffstat:

 sys/kern/sys_sig.c |  6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diffs (27 lines):

diff -r dcbd52948608 -r c24eac122418 sys/kern/sys_sig.c
--- a/sys/kern/sys_sig.c        Sat Dec 01 13:32:55 2018 +0000
+++ b/sys/kern/sys_sig.c        Sat Dec 01 14:05:33 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sys_sig.c,v 1.46 2016/08/04 06:43:43 christos Exp $    */
+/*     $NetBSD: sys_sig.c,v 1.47 2018/12/01 14:05:33 maxv Exp $        */
 
 /*-
  * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_sig.c,v 1.46 2016/08/04 06:43:43 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_sig.c,v 1.47 2018/12/01 14:05:33 maxv Exp $");
 
 #include "opt_dtrace.h"
 
@@ -766,6 +766,8 @@
         */
        sigminusset(&sigcantmask, &l->l_sigwaitset);
 
+       memset(&ksi.ksi_info, 0, sizeof(ksi.ksi_info));
+
        mutex_enter(p->p_lock);
 
        /* Check for pending signals in the process, if no - then in LWP. */