[src/trunk]: src/sys/net Fix the handling of the state returned from pfil_run...

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

details:   https://anonhg.NetBSD.org/src/rev/4bd967f731f7
branches:  trunk
changeset: 360557:4bd967f731f7
user:      tih <tih%NetBSD.org@localhost>
date:      Fri Mar 16 17:00:35 2018 +0000

description:
Fix the handling of the state returned from pfil_run_hooks().

pfil_run_hooks() invokes any registered packet filters on the packet
being handled.  It may return a (non-zero) errno, indicating that a
filter has decided that the packet should be discarded, and has freed
the mbuf.  While a non-error (0) return usually means that the packet
should be processed normally, a filter may still free the mbuf if the
packet is a fragment, and the filter is holding it for reassembly and
future evaluation.  Therefore, there must be separate tests for the
return value and for a possible discarded packet.  (See pfil(9).)

OK: christos, martin

diffstat:

 sys/net/if_vlan.c |  19 ++++++++-----------
 1 files changed, 8 insertions(+), 11 deletions(-)

diffs (49 lines):

diff -r 38945ad08410 -r 4bd967f731f7 sys/net/if_vlan.c
--- a/sys/net/if_vlan.c Fri Mar 16 12:48:54 2018 +0000
+++ b/sys/net/if_vlan.c Fri Mar 16 17:00:35 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_vlan.c,v 1.124 2018/01/15 16:36:51 maxv Exp $       */
+/*     $NetBSD: if_vlan.c,v 1.125 2018/03/16 17:00:35 tih Exp $        */
 
 /*
  * Copyright (c) 2000, 2001 The NetBSD Foundation, Inc.
@@ -78,7 +78,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_vlan.c,v 1.124 2018/01/15 16:36:51 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_vlan.c,v 1.125 2018/03/16 17:00:35 tih Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -1432,12 +1432,10 @@
 
        bpf_mtap(ifp, m);
 
-       if (pfil_run_hooks(ifp->if_pfil, &m, ifp, PFIL_OUT) != 0) {
-               if (m != NULL)
-                       m_freem(m);
-               error = 0;
+       if ((error = pfil_run_hooks(ifp->if_pfil, &m, ifp, PFIL_OUT)) != 0)
                goto out;
-       }
+       if (m == NULL)
+               goto out;
 
        /*
         * If the parent can insert the tag itself, just mark
@@ -1609,11 +1607,10 @@
        m_set_rcvif(m, &ifv->ifv_if);
        ifv->ifv_if.if_ipackets++;
 
-       if (pfil_run_hooks(ifp->if_pfil, &m, ifp, PFIL_IN) != 0) {
-               if (m != NULL)
-                       m_freem(m);
+       if (pfil_run_hooks(ifp->if_pfil, &m, ifp, PFIL_IN) != 0)
                goto out;
-       }
+       if (m == NULL)
+               goto out;
 
        m->m_flags &= ~M_PROMISC;
        if_input(&ifv->ifv_if, m);