[src/netbsd-8]: src/sys/net Pull up following revision(s) (requested by ozaki...

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

details:   https://anonhg.NetBSD.org/src/rev/d722579f4685
branches:  netbsd-8
changeset: 449459:d722579f4685
user:      martin <martin%NetBSD.org@localhost>
date:      Thu Mar 07 16:59:10 2019 +0000

description:
Pull up following revision(s) (requested by ozaki-r in ticket #1203):

        sys/net/rtsock.c: revision 1.247

Protect sysctl_rtable with KERNEL_LOCK and softnet_lock

In the function the routing table could be accessed without any locks, which was
unsafe.  Actually, on netbsd-7, a kernel panic happened(*).  The situation of
locking hasn't changed since netbsd-7 so we still need to hold the big locks on
-current (and netbsd-8) too.

Note that if NET_MPSAFE is enabled, the routing table is protected by its own
lock and we don't need the locks.

Reported and tested on netbsd-7 by sborrill@
(*) http://mail-index.netbsd.org/tech-net/2018/11/08/msg007153.html

diffstat:

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

diffs (34 lines):

diff -r f262dda8c1db -r d722579f4685 sys/net/rtsock.c
--- a/sys/net/rtsock.c  Thu Mar 07 16:56:51 2019 +0000
+++ b/sys/net/rtsock.c  Thu Mar 07 16:59:10 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rtsock.c,v 1.213.2.11 2018/11/21 12:01:11 martin Exp $ */
+/*     $NetBSD: rtsock.c,v 1.213.2.12 2019/03/07 16:59:10 martin Exp $ */
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -61,7 +61,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rtsock.c,v 1.213.2.11 2018/11/21 12:01:11 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rtsock.c,v 1.213.2.12 2019/03/07 16:59:10 martin Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -1873,6 +1873,7 @@
        w.w_needed = 0 - w.w_given;
        w.w_where = where;
 
+       SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE();
        s = splsoftnet();
        switch (w.w_op) {
 
@@ -1931,6 +1932,7 @@
                break;
        }
        splx(s);
+       SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
 
        /* check to see if we couldn't allocate memory with NOWAIT */
        if (error == ENOBUFS && w.w_tmem == 0 && w.w_tmemneeded)