[src/trunk]: src/sys/net Userland may not change the IFF_CANTCHANGE flags, ho...

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

details:   https://anonhg.NetBSD.org/src/rev/36e127f1b567
branches:  trunk
changeset: 770668:36e127f1b567
user:      dyoung <dyoung%NetBSD.org@localhost>
date:      Fri Oct 28 20:11:58 2011 +0000

description:
Userland may not change the IFF_CANTCHANGE flags, however, the kernel
may, so make sure if_flags_set() takes care of them.  Fixes a regression
in ifpromisc().

diffstat:

 sys/net/if.c |  18 ++++++++++++++----
 1 files changed, 14 insertions(+), 4 deletions(-)

diffs (45 lines):

diff -r ef931eb9ab53 -r 36e127f1b567 sys/net/if.c
--- a/sys/net/if.c      Fri Oct 28 16:42:52 2011 +0000
+++ b/sys/net/if.c      Fri Oct 28 20:11:58 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if.c,v 1.255 2011/10/25 22:26:18 dyoung Exp $  */
+/*     $NetBSD: if.c,v 1.256 2011/10/28 20:11:58 dyoung Exp $  */
 
 /*-
  * Copyright (c) 1999, 2000, 2001, 2008 The NetBSD Foundation, Inc.
@@ -90,7 +90,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if.c,v 1.255 2011/10/25 22:26:18 dyoung Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if.c,v 1.256 2011/10/28 20:11:58 dyoung Exp $");
 
 #include "opt_inet.h"
 
@@ -2154,14 +2154,24 @@
 if_flags_set(ifnet_t *ifp, const short flags)
 {
        int rc;
-       struct ifreq ifr;
 
        if (ifp->if_setflags != NULL)
                rc = (*ifp->if_setflags)(ifp, flags);
        else {
+               short cantflags;
+               struct ifreq ifr;
+
                memset(&ifr, 0, sizeof(ifr));
-               ifr.ifr_flags = flags;
+
+               cantflags = (ifp->if_flags ^ flags) & IFF_CANTCHANGE;
+               if (cantflags != 0)
+                       ifp->if_flags ^= cantflags;
+
+               ifr.ifr_flags = flags & ~IFF_CANTCHANGE;
                rc = (*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, &ifr);
+
+               if (rc != 0 && cantflags != 0)
+                       ifp->if_flags ^= cantflags;
        }
 
        return rc;