Date: Wed, 12 Feb 2020 00:31:01 +0000 (UTC) From: Eugene Grosbein <eugen@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r357786 - head/sys/netgraph Message-ID: <202002120031.01C0V1Wj099544@repo.freebsd.org>
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Author: eugen Date: Wed Feb 12 00:31:00 2020 New Revision: 357786 URL: https://svnweb.freebsd.org/changeset/base/357786 Log: ng_nat: avoid panic if attached directly to ng_ether and got short packet From the beginning, ng_nat safely assumed cleansed traffic because of limited ways it could be attached to NETGRAPH: ng_ipfw or ng_ppp only. Now as it may be attached with ng_ether too, the assumption proven wrong. Add needed check to the ng_nat. Thanks for markj for debugging this. PR: 243096 Submitted by: Lutz Donnerhacke <lutz@donnerhacke.de> Reported by: Robert James Hernandez <rob@sarcasticadmin.com> Reviewed by: markj and others MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D23091 Modified: head/sys/netgraph/ng_nat.c Modified: head/sys/netgraph/ng_nat.c ============================================================================== --- head/sys/netgraph/ng_nat.c Wed Feb 12 00:16:56 2020 (r357785) +++ head/sys/netgraph/ng_nat.c Wed Feb 12 00:31:00 2020 (r357786) @@ -806,11 +806,16 @@ ng_nat_rcvdata(hook_p hook, item_p item ) panic("Corrupted priv->dlt: %u", priv->dlt); } + if (m->m_pkthdr.len < ipofs + sizeof(struct ip)) + goto send; /* packet too short to hold IP */ + c = (char *)mtodo(m, ipofs); ip = (struct ip *)mtodo(m, ipofs); - KASSERT(m->m_pkthdr.len == ipofs + ntohs(ip->ip_len), - ("ng_nat: ip_len != m_pkthdr.len")); + if (ip->ip_v != IPVERSION) + goto send; /* other IP version, let it pass */ + if (m->m_pkthdr.len < ipofs + ntohs(ip->ip_len)) + goto send; /* packet too short (i.e. fragmented or broken) */ /* * We drop packet when:
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