diff options
| author | Mark Johnston <markj@FreeBSD.org> | 2025-01-16 15:46:37 +0000 |
|---|---|---|
| committer | Mark Johnston <markj@FreeBSD.org> | 2025-01-16 16:45:16 +0000 |
| commit | 40faf87894ff67ffdf8126fce9bb438ddf61a26f (patch) | |
| tree | 961bfc9bc4fb4ea51ec9412b2817d01abccd068a /sys | |
| parent | 886396f1b1a727c642071965612e2c2c9dd11d6c (diff) | |
ip: Defer checks for an unspecified dstaddr until after pfil hooks
To comply with Common Criteria certification requirements, it may be
necessary to ensure that packets to 0.0.0.0/::0 are dropped and logged
by the system firewall. Currently, such packets are dropped by
ip_input() and ip6_input() before reaching pfil hooks; let's defer the
checks slightly to give firewalls a chance to drop the packets
themselves, as this gives better observability. Add some regression
tests for this with pf+pflog.
Note that prior to commit 713264f6b8b, v4 packets to the unspecified
address were not dropped by the IP stack at all.
Note that ip_forward() and ip6_forward() ensure that such packets are
not forwarded; they are passed back unmodified.
Add a regression test which ensures that such packets are visible to
pflog.
Reviewed by: glebius
MFC after: 3 weeks
Sponsored by: Klara, Inc.
Sponsored by: OPNsense
Differential Revision: https://reviews.freebsd.org/D48163
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/netinet/ip_input.c | 16 | ||||
| -rw-r--r-- | sys/netinet6/ip6_fastfwd.c | 1 | ||||
| -rw-r--r-- | sys/netinet6/ip6_input.c | 17 |
3 files changed, 26 insertions, 8 deletions
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c index e00f3b77c74c..3c340b376433 100644 --- a/sys/netinet/ip_input.c +++ b/sys/netinet/ip_input.c @@ -521,11 +521,6 @@ ip_input(struct mbuf *m) goto bad; } } - /* The unspecified address can appear only as a src address - RFC1122 */ - if (__predict_false(ntohl(ip->ip_dst.s_addr) == INADDR_ANY)) { - IPSTAT_INC(ips_badaddr); - goto bad; - } if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); @@ -641,6 +636,17 @@ tooshort: } } passin: + /* + * The unspecified address can appear only as a src address - RFC1122. + * + * The check is deferred to here to give firewalls a chance to block + * (and log) such packets. ip_tryforward() will not process such + * packets. + */ + if (__predict_false(ntohl(ip->ip_dst.s_addr) == INADDR_ANY)) { + IPSTAT_INC(ips_badaddr); + goto bad; + } /* * Process options and, if not destined for us, diff --git a/sys/netinet6/ip6_fastfwd.c b/sys/netinet6/ip6_fastfwd.c index 08531cee05bf..0ed313bd49a5 100644 --- a/sys/netinet6/ip6_fastfwd.c +++ b/sys/netinet6/ip6_fastfwd.c @@ -107,6 +107,7 @@ ip6_tryforward(struct mbuf *m) IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst) || IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_src) || + IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst) || IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) || in6_localip(&ip6->ip6_dst)) return (m); diff --git a/sys/netinet6/ip6_input.c b/sys/netinet6/ip6_input.c index ec819a12628d..68e4be66537b 100644 --- a/sys/netinet6/ip6_input.c +++ b/sys/netinet6/ip6_input.c @@ -621,10 +621,10 @@ ip6_input(struct mbuf *m) IP_PROBE(receive, NULL, NULL, ip6, rcvif, NULL, ip6); /* - * Check against address spoofing/corruption. + * Check against address spoofing/corruption. The unspecified address + * is checked further below. */ - if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) || - IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) { + if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) { /* * XXX: "badscope" is not very suitable for a multicast source. */ @@ -750,6 +750,17 @@ ip6_input(struct mbuf *m) passin: /* + * The check is deferred to here to give firewalls a chance to block + * (and log) such packets. ip6_tryforward() will not process such + * packets. + */ + if (__predict_false(IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst))) { + IP6STAT_INC(ip6s_badscope); + in6_ifstat_inc(rcvif, ifs6_in_addrerr); + goto bad; + } + + /* * Disambiguate address scope zones (if there is ambiguity). * We first make sure that the original source or destination address * is not in our internal form for scoped addresses. Such addresses |