Date: Wed, 20 May 2026 15:34:52 +0000 From: Cy Schubert <cy@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 8dfb0805fc31 - main - ipfilter: Validate length before checksum Message-ID: <6a0dd49c.45e35.f3ed5e8@gitrepo.freebsd.org>
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The branch main has been updated by cy: URL: https://cgit.FreeBSD.org/src/commit/?id=8dfb0805fc31cd78940429ab0560dae7e8ab6536 commit 8dfb0805fc31cd78940429ab0560dae7e8ab6536 Author: Cy Schubert <cy@FreeBSD.org> AuthorDate: 2026-05-11 15:44:52 +0000 Commit: Cy Schubert <cy@FreeBSD.org> CommitDate: 2026-05-20 15:32:37 +0000 ipfilter: Validate length before checksum Validate the length of the packet listed in the mbuf is the same as the calculated packet length. If not reject the packet and bump the bad packet stat. PR: 295198 MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D57095 --- sys/netpfil/ipfilter/netinet/fil.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/sys/netpfil/ipfilter/netinet/fil.c b/sys/netpfil/ipfilter/netinet/fil.c index 9217572aac50..cabc6c350981 100644 --- a/sys/netpfil/ipfilter/netinet/fil.c +++ b/sys/netpfil/ipfilter/netinet/fil.c @@ -1991,7 +1991,7 @@ ipf_checkcipso(fr_info_t *fin, u_char *s, int ol) /* ------------------------------------------------------------------------ */ /* Function: ipf_makefrip */ -/* Returns: int - 0 == packet ok, -1 == packet freed */ +/* Returns: int - 0 == packet ok, -1 == packet freed or bad length */ /* Parameters: hlen(I) - length of IP packet header */ /* ip(I) - pointer to the IP header */ /* fin(IO) - pointer to packet information */ @@ -2019,14 +2019,23 @@ ipf_makefrip(int hlen, ip_t *ip, fr_info_t *fin) if (v == 4) { fin->fin_plen = ntohs(ip->ip_len); fin->fin_dlen = fin->fin_plen - hlen; - ipf_pr_ipv4hdr(fin); + if (fin->fin_m != NULL && fin->fin_m->m_flags & M_PKTHDR && fin->fin_m->m_pkthdr.len < fin->fin_plen) { + LBUMPD(ipf_stats[fin->fin_out], fr_bad); + return (-1); + } else { + ipf_pr_ipv4hdr(fin); + } #ifdef USE_INET6 } else if (v == 6) { fin->fin_plen = ntohs(((ip6_t *)ip)->ip6_plen); fin->fin_dlen = fin->fin_plen; fin->fin_plen += hlen; - - ipf_pr_ipv6hdr(fin); + if (fin->fin_m != NULL && fin->fin_m->m_flags & M_PKTHDR && fin->fin_m->m_pkthdr.len < fin->fin_plen) { + LBUMPD(ipf_stats[fin->fin_out], fr_v6_bad); + return (-1); + } else { + ipf_pr_ipv6hdr(fin); + } #endif } if (fin->fin_ip == NULL) {home | help
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