check pf rule "set prio" values consistently.

consistently means we do the check in pf_rule_copyin() so both
DIOCADDRULE and DIOCCHANGERULE have the prio values checked. this in
turn prevents invalid prio values getting set on a rule via
DIOCCHANGERULE.

this was caught by a kassert in the ifq priq code firing.

Reported-by: syzbot+a8f8e24a44b441e71d93@syzkaller.appspotmail.com
ok sashan@

sys/net/pf_ioctl.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: pf_ioctl.c,v 1.372 2022/02/09 11:42:58 sashan Exp $ */
+/*	$OpenBSD: pf_ioctl.c,v 1.373 2022/02/16 04:25:34 dlg Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -1370,15 +1370,6 @@ pfioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p)
 			break;
 		}
 
-		if (rule->scrub_flags & PFSTATE_SETPRIO &&
-		    (rule->set_prio[0] > IFQ_MAXPRIO ||
-		    rule->set_prio[1] > IFQ_MAXPRIO)) {
-			error = EINVAL;
-			pf_rule_free(rule);
-			rule = NULL;
-			break;
-		}
-
 		NET_LOCK();
 		PF_LOCK();
 		pr->anchor[sizeof(pr->anchor) - 1] = '\0';
@@ -3071,6 +3062,11 @@ pf_rule_copyin(struct pf_rule *from, struct pf_rule *to)
 {
 	int i;
 
+	if (from->scrub_flags & PFSTATE_SETPRIO &&
+	    (from->set_prio[0] > IFQ_MAXPRIO ||
+	    from->set_prio[1] > IFQ_MAXPRIO))
+		return (EINVAL);
+
 	to->src = from->src;
 	to->src.addr.p.tbl = NULL;
 	to->dst = from->dst;