Use a distinct variable while iterating the list of existing devices.

ok mvs@

Reported-by: syzbot+e2d1df67f742a5a47938@syzkaller.appspotmail.com
Reported-by: syzbot+72298724beda82ec8e7f@syzkaller.appspotmail.com

diff --git a/sys/net/if_pppx.c b/sys/net/if_pppx.c
index b4f8904..00e6bd9 100644 (file)
--- a/sys/net/if_pppx.c
+++ b/sys/net/if_pppx.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_pppx.c,v 1.112 2021/12/30 00:49:41 mvs Exp $ */
+/*     $OpenBSD: if_pppx.c,v 1.113 2021/12/30 14:25:39 anton Exp $ */
 
 /*
  * Copyright (c) 2010 Claudio Jeker <claudio@openbsd.org>
@@ -1006,13 +1006,14 @@ pppacattach(int n)
 int
 pppacopen(dev_t dev, int flags, int mode, struct proc *p)
 {
-       struct pppac_softc *sc;
+       struct pppac_softc *sc, *tmp;
        struct ifnet *ifp;
        struct pipex_session *session;
 
        sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK|M_ZERO);
-       LIST_FOREACH(sc, &pppac_devs, sc_entry) {
-               if (sc->sc_dev == dev) {
+       sc->sc_dev = dev;
+       LIST_FOREACH(tmp, &pppac_devs, sc_entry) {
+               if (tmp->sc_dev == dev) {
                        free(sc, M_DEVBUF, sizeof(*sc));
                        return (EBUSY);
                }
@@ -1025,8 +1026,6 @@ pppacopen(dev_t dev, int flags, int mode, struct proc *p)
        session->ownersc = sc;
        sc->sc_multicast_session = session;
 
-       sc->sc_dev = dev;
-
        mtx_init(&sc->sc_rsel_mtx, IPL_SOFTNET);
        mtx_init(&sc->sc_wsel_mtx, IPL_SOFTNET);
        mq_init(&sc->sc_mq, IFQ_MAXLEN, IPL_SOFTNET);