pf: Reject rules with invalid port ranges

Ranges where the left boundary is bigger than the right one are always bogus
as they work like `port any' (`port 34<>12' means "all ports") or in way
that inverts the rule's action (`pass ... port 34:12' means "pass no port at
all").

Add checks for all ranges and invalidate those that yield no or all ports.

For this to work on redirections, make pfctl(8) pass the range's type,
otherwise boundary including ranges are not detected as such;  that is to
say, `struct pf_pool's `port_op' member was unused in the kernel so far.

`rdr-to' rules with invalid ranges could panic the kernel when hit.
Reported-by: [email protected]

OK sashan

Obtained from:	OpenBSD, kn <[email protected]>, 39c2a1337a
Sponsored by:	Rubicon Communications, LLC ("Netgate")

sys/netpfil/pf/pf_ioctl.c

@@ -2041,6 +2041,19 @@ pf_ioctl_getrules(struct pfioc_rule *pr)
 	return (0);
 }
 
+static int
+pf_validate_range(uint8_t op, uint16_t port[2])
+{
+	uint16_t a = ntohs(port[0]);
+	uint16_t b = ntohs(port[1]);
+
+	if ((op == PF_OP_RRG && a > b) ||  /* 34:12,  i.e. none */
+	    (op == PF_OP_IRG && a >= b) || /* 34><12, i.e. none */
+	    (op == PF_OP_XRG && a > b))	   /* 34<>22, i.e. all */
+		return 1;
+	return 0;
+}
+
 int
 pf_ioctl_addrule(struct pf_krule *rule, uint32_t ticket,
     uint32_t pool_ticket, const char *anchor, const char *anchor_call,
@@ -2060,6 +2073,11 @@ pf_ioctl_addrule(struct pf_krule *rule, uint32_t ticket,
 
 #define	ERROUT(x)	ERROUT_FUNCTION(errout, x)
 
+	if (pf_validate_range(rule->src.port_op, rule->src.port))
+		ERROUT(EINVAL);
+	if (pf_validate_range(rule->dst.port_op, rule->dst.port))
+		ERROUT(EINVAL);
+
 	if (rule->ifname[0])
 		kif = pf_kkif_create(M_WAITOK);
 	if (rule->rcv_ifname[0])