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From OpenBSD, rev. 1.524, 1.528, 1.529

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Deal with IPv6 routing headers (see FreeBSD-SA-07:03.ipv6 for background)
Block IPv6 packets with routing headers by default, unless 'allow-opts'
is specified. Block RH0 unconditionally. Deal with ip6_plen 0.

MFC after:	1 week
Discussed with:	mlaier
This commit is contained in:
Daniel Hartmeier 2007-05-21 20:08:59 +00:00
parent bf5a3266f7
commit 67debc100c
1 changed files with 52 additions and 3 deletions
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55
sys/contrib/pf/net/pf.c
View File

@ -6780,7 +6780,7 @@ pf_test6(int dir, struct ifnet *ifp, struct mbuf **m0,
struct pf_state *s = NULL;
struct pf_ruleset *ruleset = NULL;
struct pf_pdesc pd;
int off, terminal = 0, dirndx;
int off, terminal = 0, dirndx, rh_cnt = 0;
#ifdef __FreeBSD__
PF_LOCK();
@ -6844,6 +6844,18 @@ pf_test6(int dir, struct ifnet *ifp, struct mbuf **m0,
m = *m0;
h = mtod(m, struct ip6_hdr *);
#if 1
/*
* we do not support jumbogram yet. if we keep going, zero ip6_plen
* will do something bad, so drop the packet for now.
*/
if (htons(h->ip6_plen) == 0) {
action = PF_DROP;
REASON_SET(&reason, PFRES_NORM); /*XXX*/
goto done;
}
#endif
pd.src = (struct pf_addr *)&h->ip6_src;
pd.dst = (struct pf_addr *)&h->ip6_dst;
PF_ACPY(&pd.baddr, dir == PF_OUT ? pd.src : pd.dst, AF_INET6);
@ -6863,9 +6875,38 @@ pf_test6(int dir, struct ifnet *ifp, struct mbuf **m0,
if (action == PF_DROP)
REASON_SET(&reason, PFRES_FRAG);
goto done;
case IPPROTO_ROUTING: {
struct ip6_rthdr rthdr;
if (rh_cnt++) {
DPFPRINTF(PF_DEBUG_MISC,
("pf: IPv6 more than one rthdr\n"));
action = PF_DROP;
REASON_SET(&reason, PFRES_IPOPTIONS);
log = 1;
goto done;
}
if (!pf_pull_hdr(m, off, &rthdr, sizeof(rthdr), NULL,
&reason, pd.af)) {
DPFPRINTF(PF_DEBUG_MISC,
("pf: IPv6 short rthdr\n"));
action = PF_DROP;
REASON_SET(&reason, PFRES_SHORT);
log = 1;
goto done;
}
if (rthdr.ip6r_type == IPV6_RTHDR_TYPE_0) {
DPFPRINTF(PF_DEBUG_MISC,
("pf: IPv6 rthdr0\n"));
action = PF_DROP;
REASON_SET(&reason, PFRES_IPOPTIONS);
log = 1;
goto done;
}
/* fallthrough */
}
case IPPROTO_AH:
case IPPROTO_HOPOPTS:
case IPPROTO_ROUTING:
case IPPROTO_DSTOPTS: {
/* get next header and header length */
struct ip6_ext opt6;
@ -7032,7 +7073,15 @@ pf_test6(int dir, struct ifnet *ifp, struct mbuf **m0,
}
done:
/* XXX handle IPv6 options, if not allowed. not implemented. */
/* handle dangerous IPv6 extension headers. */
if (action == PF_PASS && rh_cnt &&
!((s && s->allow_opts) || r->allow_opts)) {
action = PF_DROP;
REASON_SET(&reason, PFRES_IPOPTIONS);
log = 1;
DPFPRINTF(PF_DEBUG_MISC,
("pf: dropping packet with dangerous v6 headers\n"));
}
if (s && s->tag)
pf_tag_packet(m, pf_get_tag(m), s->tag);