From 38d34b673a8a3bd439a0191c00a865f304217775 Mon Sep 17 00:00:00 2001 From: Alexander Motin Date: Sat, 31 Jan 2009 12:48:09 +0000 Subject: MFC rev. 187495 Check for infinite recursion possible on some broken PPTP/L2TP/... VPN setups. Mark packets with mbuf_tag on first interface passage and drop on second. PR: ports/129625, ports/125303 --- sys/netgraph/ng_iface.c | 18 ++++++++++++++++++ sys/netgraph/ng_iface.h | 3 +++ 2 files changed, 21 insertions(+) (limited to 'sys/netgraph') diff --git a/sys/netgraph/ng_iface.c b/sys/netgraph/ng_iface.c index fec243215d35..f40cbe498eeb 100644 --- a/sys/netgraph/ng_iface.c +++ b/sys/netgraph/ng_iface.c @@ -353,6 +353,7 @@ static int ng_iface_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, struct rtentry *rt0) { + struct m_tag *mtag; uint32_t af; int error; @@ -363,6 +364,23 @@ ng_iface_output(struct ifnet *ifp, struct mbuf *m, return (ENETDOWN); } + /* Protect from deadly infinite recursion. */ + while ((mtag = m_tag_locate(m, MTAG_NGIF, MTAG_NGIF_CALLED, NULL))) { + if (*(struct ifnet **)(mtag + 1) == ifp) { + log(LOG_NOTICE, "Loop detected on %s\n", ifp->if_xname); + m_freem(m); + return (EDEADLK); + } + } + mtag = m_tag_alloc(MTAG_NGIF, MTAG_NGIF_CALLED, sizeof(struct ifnet *), + M_NOWAIT); + if (mtag == NULL) { + m_freem(m); + return (ENOMEM); + } + *(struct ifnet **)(mtag + 1) = ifp; + m_tag_prepend(m, mtag); + /* BPF writes need to be handled specially. */ if (dst->sa_family == AF_UNSPEC) { bcopy(dst->sa_data, &af, sizeof(af)); diff --git a/sys/netgraph/ng_iface.h b/sys/netgraph/ng_iface.h index 54dfa8c78690..58fb44230582 100644 --- a/sys/netgraph/ng_iface.h +++ b/sys/netgraph/ng_iface.h @@ -72,4 +72,7 @@ enum { NGM_IFACE_GET_IFINDEX, }; +#define MTAG_NGIF NGM_IFACE_COOKIE +#define MTAG_NGIF_CALLED 0 | MTAG_PERSISTENT + #endif /* _NETGRAPH_NG_IFACE_H_ */ -- cgit v1.3