[src/trunk]: src/sys/kern Fix stack info leak.

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

details:   https://anonhg.NetBSD.org/src/rev/54e1b654e7b8
branches:  trunk
changeset: 837332:54e1b654e7b8
user:      maxv <maxv%NetBSD.org@localhost>
date:      Thu Nov 29 11:45:52 2018 +0000

description:
Fix stack info leak.

        + Possible info leak: [len=136, leaked=92]
        | #0 0xffffffff80baf397 in kleak_copyout
        | #1 0xffffffff80bd4155 in ptrace_copyout_siginfo
        | #2 0xffffffff80bd5348 in do_ptrace
        | #3 0xffffffff80bd40fe in sys_ptrace
        | #4 0xffffffff80259c42 in syscall

diffstat:

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

diffs (26 lines):

diff -r b33914dcc432 -r 54e1b654e7b8 sys/kern/sys_ptrace_common.c
--- a/sys/kern/sys_ptrace_common.c      Thu Nov 29 11:23:49 2018 +0000
+++ b/sys/kern/sys_ptrace_common.c      Thu Nov 29 11:45:52 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sys_ptrace_common.c,v 1.45 2018/06/23 03:32:48 christos Exp $  */
+/*     $NetBSD: sys_ptrace_common.c,v 1.46 2018/11/29 11:45:52 maxv Exp $      */
 
 /*-
  * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
@@ -118,7 +118,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_ptrace_common.c,v 1.45 2018/06/23 03:32:48 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_ptrace_common.c,v 1.46 2018/11/29 11:45:52 maxv Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ptrace.h"
@@ -570,6 +570,7 @@
 {
        struct ptrace_siginfo psi;
 
+       memset(&psi, 0, sizeof(psi));
        psi.psi_siginfo._info = t->p_sigctx.ps_info;
        psi.psi_lwpid = t->p_sigctx.ps_lwp;
        DPRINTF(("%s: lwp=%d signal=%d\n", __func__, psi.psi_lwpid,