Date: Mon, 4 Apr 2011 19:16:44 GMT From: Karim Fodil-Lemelin <fodillemlinkarim@gmail.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/156180: ipfw checks TCP options on non-contiguous header Message-ID: <201104041916.p34JGiXe053757@red.freebsd.org> Resent-Message-ID: <201104041920.p34JK9Vo078544@freefall.freebsd.org>
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>Number: 156180 >Category: kern >Synopsis: ipfw checks TCP options on non-contiguous header >Confidential: no >Severity: non-critical >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Mon Apr 04 19:20:09 UTC 2011 >Closed-Date: >Last-Modified: >Originator: Karim Fodil-Lemelin >Release: CURRENT >Organization: >Environment: >Description: When using tcpopt_match in ipfw there is no guarantee that the TCP option space matched is not bogus. This is because the case IPPROTO_TCP does not do an m_pullup on the entire IP+TCP+TCP option header. >How-To-Repeat: >Fix: The attached patch will call m_pullup on the TCP option space if it wasn't done already. Patch attached with submission follows: Index: netinet/ipfw/ip_fw2.c =================================================================== --- netinet/ipfw/ip_fw2.c (revision 219967) +++ netinet/ipfw/ip_fw2.c (working copy) @@ -949,6 +949,11 @@ case IPPROTO_TCP: PULLUP_TO(hlen, ulp, struct tcphdr); + /* kfl: check 'contiguousity' of the option space */ + if (m->m_len < (hlen + (TCP(ulp)->th_off << 2))) { + if ((m = m_pullup(m, hlen+(TCP(ulp)->th_off << 2))) == NULL) + goto pullup_failed; + } dst_port = TCP(ulp)->th_dport; src_port = TCP(ulp)->th_sport; /* save flags for dynamic rules */ @@ -1117,6 +1122,11 @@ switch (proto) { case IPPROTO_TCP: PULLUP_TO(hlen, ulp, struct tcphdr); + /* kfl: check 'contiguousity' of the option space */ + if (m->m_len < (hlen + (TCP(ulp)->th_off << 2))) { + if ((m = m_pullup(m, hlen+(TCP(ulp)->th_off << 2))) == NULL) + goto pullup_failed; + } dst_port = TCP(ulp)->th_dport; src_port = TCP(ulp)->th_sport; /* save flags for dynamic rules */ >Release-Note: >Audit-Trail: >Unformatted:
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