Hi,
We accept more TCP reset packets in pf, if fragment reassembly is
turned off. That does not make sense to me. It came into the tree
here:
revision 1.443
date: 2004/04/27 18:28:07; author: frantzen; state: Exp; lines: +9 -6
validate the sequence numbers on TCP resets are an exact match. check is only
enabled when we're doing full frag reassembly and thus have full seq info
ok markus@
Nowadays we have full fragment reassembly on by default, the fragment
cache has gone. When the user turns it off, he has to cope with
the consequences. Fragmented TCP reset packets too short for the
sequence number are likely to be evil.
ok to remove PFDESC_IP_REAS?
bluhm
Index: net/pf.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/pf.c,v
retrieving revision 1.747
diff -u -p -r1.747 pf.c
--- net/pf.c 2 Jun 2011 22:08:40 -0000 1.747
+++ net/pf.c 17 Jun 2011 23:59:35 -0000
@@ -3617,8 +3617,7 @@ pf_tcp_track_full(struct pf_state_peer *
(ackskew <= (MAXACKWINDOW << sws)) &&
/* Acking not more than one window forward */
((th->th_flags & TH_RST) == 0 || orig_seq == src->seqlo ||
- (orig_seq == src->seqlo + 1) || (orig_seq + 1 == src->seqlo) ||
- (pd->flags & PFDESC_IP_REAS) == 0)) {
+ (orig_seq == src->seqlo + 1) || (orig_seq + 1 == src->seqlo))) {
/* Require an exact/+1 sequence match on resets when possible */
if (dst->scrub || src->scrub) {
@@ -5810,7 +5809,7 @@ pf_test(int dir, struct ifnet *ifp, stru
h = mtod(m, struct ip *);
if (pf_status.reass &&
(h->ip_off & htons(IP_MF | IP_OFFMASK)) &&
- pf_normalize_ip(m0, dir, kif, &reason, &pd) != PF_PASS) {
+ pf_normalize_ip(m0, dir, kif, &reason) != PF_PASS) {
action = PF_DROP;
goto done;
}
@@ -6090,7 +6089,7 @@ pf_test6(int fwdir, struct ifnet *ifp, s
/* packet reassembly */
if (pf_status.reass &&
- pf_normalize_ip6(m0, fwdir, kif, &reason, &pd) != PF_PASS) {
+ pf_normalize_ip6(m0, fwdir, kif, &reason) != PF_PASS) {
action = PF_DROP;
goto done;
}
Index: net/pf_norm.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/pf_norm.c,v
retrieving revision 1.133
diff -u -p -r1.133 pf_norm.c
--- net/pf_norm.c 24 May 2011 14:01:52 -0000 1.133
+++ net/pf_norm.c 17 Jun 2011 23:58:35 -0000
@@ -740,7 +740,7 @@ pf_refragment6(struct mbuf **m0, struct
int
pf_normalize_ip(struct mbuf **m0, int dir, struct pfi_kif *kif,
- u_short *reason, struct pf_pdesc *pd)
+ u_short *reason)
{
struct mbuf *m = *m0;
struct ip *h = mtod(m, struct ip *);
@@ -787,7 +787,6 @@ pf_normalize_ip(struct mbuf **m0, int di
if (h->ip_off & ~htons(IP_DF))
h->ip_off &= htons(IP_DF);
- pd->flags |= PFDESC_IP_REAS;
return (PF_PASS);
drop:
@@ -798,7 +797,7 @@ pf_normalize_ip(struct mbuf **m0, int di
#ifdef INET6
int
pf_normalize_ip6(struct mbuf **m0, int dir, struct pfi_kif *kif,
- u_short *reason, struct pf_pdesc *pd)
+ u_short *reason)
{
struct mbuf *m = *m0;
struct ip6_hdr *h = mtod(m, struct ip6_hdr *);
@@ -924,7 +923,6 @@ pf_normalize_ip6(struct mbuf **m0, int d
if (m == NULL)
return (PF_PASS);
- pd->flags |= PFDESC_IP_REAS;
return (PF_PASS);
shortpkt:
Index: net/pfvar.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/pfvar.h,v
retrieving revision 1.332
diff -u -p -r1.332 pfvar.h
--- net/pfvar.h 24 May 2011 14:01:52 -0000 1.332
+++ net/pfvar.h 17 Jun 2011 23:58:57 -0000
@@ -1221,8 +1221,6 @@ struct pf_pdesc {
u_int16_t *proto_sum;
u_int16_t rdomain; /* original routing domain */
- u_int16_t flags;
-#define PFDESC_IP_REAS 0x0002 /* IP frags would've been reassembled */
sa_family_t af;
u_int8_t proto;
u_int8_t tos;
@@ -1777,10 +1775,8 @@ int pf_match_gid(u_int8_t, gid_t, gid_t,
int pf_refragment6(struct mbuf **, struct m_tag *mtag, int);
void pf_normalize_init(void);
-int pf_normalize_ip(struct mbuf **, int, struct pfi_kif *, u_short *,
- struct pf_pdesc *);
-int pf_normalize_ip6(struct mbuf **, int, struct pfi_kif *, u_short *,
- struct pf_pdesc *);
+int pf_normalize_ip(struct mbuf **, int, struct pfi_kif *, u_short *);
+int pf_normalize_ip6(struct mbuf **, int, struct pfi_kif *, u_short *);
int pf_normalize_tcp(int, struct pfi_kif *, struct mbuf *, int, int, void *,
struct pf_pdesc *);
void pf_normalize_tcp_cleanup(struct pf_state *);
