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/netinet/ip_input.c | |
| 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/netinet/ip_input.c')
| -rw-r--r-- | sys/netinet/ip_input.c | 16 |
1 files changed, 11 insertions, 5 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, |