Date: Thu, 7 May 2020 01:28:59 +0000 (UTC) From: Michael Tuexen <tuexen@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r360733 - stable/11/sys/netinet6 Message-ID: <202005070128.0471Sxmv055158@repo.freebsd.org>
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Author: tuexen Date: Thu May 7 01:28:59 2020 New Revision: 360733 URL: https://svnweb.freebsd.org/changeset/base/360733 Log: MFC r352511: Improve IPv6 handling over the loopback interface 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 Sponsored by: Netflix, Inc. Differential Revision: https://reviews.freebsd.org/D21664 Modified: stable/11/sys/netinet6/ip6_input.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/netinet6/ip6_input.c ============================================================================== --- stable/11/sys/netinet6/ip6_input.c Thu May 7 01:16:32 2020 (r360732) +++ stable/11/sys/netinet6/ip6_input.c Thu May 7 01:28:59 2020 (r360733) @@ -402,20 +402,22 @@ VNET_SYSUNINIT(inet6, SI_SUB_PROTO_DOMAIN, SI_ORDER_TH #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 *); /* @@ -855,7 +857,7 @@ 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;
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