From 699a34f40f393557f0ad510b11cb72d6b818c35d Mon Sep 17 00:00:00 2001 From: tuexen Date: Thu, 19 Sep 2019 10:22:29 +0000 Subject: [PATCH] When processing an incoming IPv6 packet over the loopback interface which contains Hop-by-Hop options, the mbuf chain is potentially changed in ip6_hopopts_input(), called by ip6_input_hbh(). This can happen, because of the the use of IP6_EXTHDR_CHECK, which might call m_pullup(). So provide the updated pointer back to the called of ip6_input_hbh() to avoid using a freed mbuf chain in`ip6_input()`. Reviewed by: markj@ MFC after: 3 days Sponsored by: Netflix, Inc. Differential Revision: https://reviews.freebsd.org/D21664 --- sys/netinet6/ip6_input.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/sys/netinet6/ip6_input.c b/sys/netinet6/ip6_input.c index 626e4f0b2018..60a6c501158f 100644 --- a/sys/netinet6/ip6_input.c +++ b/sys/netinet6/ip6_input.c @@ -403,20 +403,22 @@ VNET_SYSUNINIT(inet6, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, ip6_destroy, NULL); #endif static int -ip6_input_hbh(struct mbuf *m, uint32_t *plen, uint32_t *rtalert, int *off, +ip6_input_hbh(struct mbuf **mp, uint32_t *plen, uint32_t *rtalert, int *off, int *nxt, int *ours) { + struct mbuf *m; struct ip6_hdr *ip6; struct ip6_hbh *hbh; - if (ip6_hopopts_input(plen, rtalert, &m, off)) { + if (ip6_hopopts_input(plen, rtalert, mp, off)) { #if 0 /*touches NULL pointer*/ - in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard); + in6_ifstat_inc((*mp)->m_pkthdr.rcvif, ifs6_in_discard); #endif goto out; /* m have already been freed */ } /* adjust pointer */ + m = *mp; ip6 = mtod(m, struct ip6_hdr *); /* @@ -854,7 +856,7 @@ passin: */ plen = (u_int32_t)ntohs(ip6->ip6_plen); if (ip6->ip6_nxt == IPPROTO_HOPOPTS) { - if (ip6_input_hbh(m, &plen, &rtalert, &off, &nxt, &ours) != 0) + if (ip6_input_hbh(&m, &plen, &rtalert, &off, &nxt, &ours) != 0) return; } else nxt = ip6->ip6_nxt;