[src/trunk]: src/sys/net Fix to aquire pppoe_softc_list_lock before read and ...

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

details:   https://anonhg.NetBSD.org/src/rev/720d0de80793
branches:  trunk
changeset: 323515:720d0de80793
user:      yamaguchi <yamaguchi%NetBSD.org@localhost>
date:      Mon Jun 18 09:53:45 2018 +0000

description:
Fix to aquire pppoe_softc_list_lock before read and write the list

ok by knakahara@n.o

diffstat:

 sys/net/if_pppoe.c |  51 +++++++++++++++++++++++++++++++++++++++------------
 1 files changed, 39 insertions(+), 12 deletions(-)

diffs (137 lines):

diff -r d11de93b3bee -r 720d0de80793 sys/net/if_pppoe.c
--- a/sys/net/if_pppoe.c        Mon Jun 18 09:49:05 2018 +0000
+++ b/sys/net/if_pppoe.c        Mon Jun 18 09:53:45 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: if_pppoe.c,v 1.139 2018/06/18 09:49:05 yamaguchi Exp $ */
+/* $NetBSD: if_pppoe.c,v 1.140 2018/06/18 09:53:45 yamaguchi Exp $ */
 
 /*-
  * Copyright (c) 2002, 2008 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_pppoe.c,v 1.139 2018/06/18 09:49:05 yamaguchi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_pppoe.c,v 1.140 2018/06/18 09:53:45 yamaguchi Exp $");
 
 #ifdef _KERNEL_OPT
 #include "pppoe.h"
@@ -277,8 +277,11 @@
 {
        int error = 0;
 
-       if (!LIST_EMPTY(&pppoe_softc_list))
+       rw_enter(&pppoe_softc_list_lock, RW_READER);
+       if (!LIST_EMPTY(&pppoe_softc_list)) {
+               rw_exit(&pppoe_softc_list_lock);
                error = EBUSY;
+       }
 
        if (error == 0) {
                if_clone_detach(&pppoe_cloner);
@@ -338,9 +341,12 @@
        sppp_attach(&sc->sc_sppp.pp_if);
 
        bpf_attach(&sc->sc_sppp.pp_if, DLT_PPP_ETHER, 0);
+       rw_enter(&pppoe_softc_list_lock, RW_READER);
        if (LIST_EMPTY(&pppoe_softc_list)) {
                pfil_add_ihook(pppoe_ifattach_hook, NULL, PFIL_IFNET, if_pfil);
        }
+       rw_exit(&pppoe_softc_list_lock);
+
        if_register(&sc->sc_sppp.pp_if);
 
        rw_init(&sc->sc_lock);
@@ -424,14 +430,18 @@
 {
        struct pppoe_softc *sc, *t;
 
-       if (LIST_EMPTY(&pppoe_softc_list))
+       rw_enter(&pppoe_softc_list_lock, RW_READER);
+       if (LIST_EMPTY(&pppoe_softc_list)) {
+               rw_exit(&pppoe_softc_list_lock);
                return NULL;
+       }
 
-       if (len != sizeof sc)
+       if (len != sizeof sc) {
+               rw_exit(&pppoe_softc_list_lock);
                return NULL;
+       }
        memcpy(&t, token, len);
 
-       rw_enter(&pppoe_softc_list_lock, RW_READER);
        LIST_FOREACH(sc, &pppoe_softc_list, sc_list) {
                if (sc == t) {
                        PPPOE_LOCK(sc, lock);
@@ -703,9 +713,12 @@
                 * got service name, concentrator name, and/or host unique.
                 * ignore if we have no interfaces with IFF_PASSIVE|IFF_UP.
                 */
-               if (LIST_EMPTY(&pppoe_softc_list))
+               rw_enter(&pppoe_softc_list_lock, RW_READER);
+               if (LIST_EMPTY(&pppoe_softc_list)) {
+                       rw_exit(&pppoe_softc_list_lock);
                        goto done;
-               rw_enter(&pppoe_softc_list_lock, RW_READER);
+               }
+
                LIST_FOREACH(sc, &pppoe_softc_list, sc_list) {
                        PPPOE_LOCK(sc, RW_WRITER);
                        if (!(sc->sc_sppp.pp_if.if_flags & IFF_UP)) {
@@ -768,8 +781,12 @@
                m_put_rcvif_psref(rcvif, &psref);
                if (sc == NULL) {
                        /* be quiet if there is not a single pppoe instance */
-                       if (!LIST_EMPTY(&pppoe_softc_list))
-                               printf("pppoe: received PADR but could not find request for it\n");
+                       rw_enter(&pppoe_softc_list_lock, RW_READER);
+                       if (!LIST_EMPTY(&pppoe_softc_list)) {
+                               printf("pppoe: received PADR"
+                                   " but could not find request for it\n");
+                       }
+                       rw_exit(&pppoe_softc_list_lock);
                        goto done;
                }
 
@@ -818,8 +835,12 @@
 
                if (sc == NULL) {
                        /* be quiet if there is not a single pppoe instance */
-                       if (!LIST_EMPTY(&pppoe_softc_list))
-                               printf("pppoe: received PADO but could not find request for it\n");
+                       rw_enter(&pppoe_softc_list_lock, RW_READER);
+                       if (!LIST_EMPTY(&pppoe_softc_list)) {
+                               printf("pppoe: received PADO"
+                                   " but could not find request for it\n");
+                       }
+                       rw_exit(&pppoe_softc_list_lock);
                        goto done;
                }
 
@@ -959,9 +980,12 @@
        /*
         * Avoid error messages if there is not a single PPPoE instance.
         */
+       rw_enter(&pppoe_softc_list_lock, RW_READER);
        if (!LIST_EMPTY(&pppoe_softc_list)) {
+               rw_exit(&pppoe_softc_list_lock);
                pppoe_dispatch_disc_pkt(m, 0);
        } else {
+               rw_exit(&pppoe_softc_list_lock);
                m_freem(m);
        }
 }
@@ -993,9 +1017,12 @@
        /*
         * Avoid error messages if there is not a single PPPoE instance.
         */
+       rw_enter(&pppoe_softc_list_lock, RW_READER);
        if (LIST_EMPTY(&pppoe_softc_list)) {
+               rw_exit(&pppoe_softc_list_lock);
                goto drop;
        }
+       rw_exit(&pppoe_softc_list_lock);
 
        if (term_unknown) {
                memcpy(shost, mtod(m, struct ether_header*)->ether_shost,