From c5e105655b92fa48726fc8f1bb1a00d39983e4f4 Mon Sep 17 00:00:00 2001
From: Kristof Provost <kp@FreeBSD.org>
Date: Sat, 28 Apr 2018 13:16:58 +0000
Subject: [PATCH] pfctl: Don't break connections on skipped interfaces on
 reload

On reload we used to first flush everything, including the list of skipped
interfaces.  This can lead to termination of these connections if they send
packets before the new configuration is applied.

Note that this doesn't currently happen on 12 or 11, because of special EACCES
handling introduced in r315514. This special behaviour in tcp_output() may
change, hence the fix in pfctl.

PR:		214613
---
 sbin/pfctl/pfctl.c | 47 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/sbin/pfctl/pfctl.c b/sbin/pfctl/pfctl.c
index 5b4c67de6629..98564ab1ca33 100644
--- a/sbin/pfctl/pfctl.c
+++ b/sbin/pfctl/pfctl.c
@@ -67,6 +67,9 @@ void	 usage(void);
 int	 pfctl_enable(int, int);
 int	 pfctl_disable(int, int);
 int	 pfctl_clear_stats(int, int);
+int	 pfctl_get_skip_ifaces(void);
+int	 pfctl_check_skip_ifaces(char *);
+int	 pfctl_clear_skip_ifaces(struct pfctl *);
 int	 pfctl_clear_interface_flags(int, int);
 int	 pfctl_clear_rules(int, int, char *);
 int	 pfctl_clear_nat(int, int, char *);
@@ -106,6 +109,7 @@ const char	*pfctl_lookup_option(char *, const char * const *);
 
 static struct pf_anchor_global	 pf_anchors;
 static struct pf_anchor	 pf_main_anchor;
+static struct pfr_buffer skip_b;
 
 static const char	*clearopt;
 static char		*rulesopt;
@@ -294,6 +298,44 @@ pfctl_clear_stats(int dev, int opts)
 	return (0);
 }
 
+int
+pfctl_get_skip_ifaces(void)
+{
+	bzero(&skip_b, sizeof(skip_b));
+	skip_b.pfrb_type = PFRB_IFACES;
+	for (;;) {
+		pfr_buf_grow(&skip_b, skip_b.pfrb_size);
+		skip_b.pfrb_size = skip_b.pfrb_msize;
+		if (pfi_get_ifaces(NULL, skip_b.pfrb_caddr, &skip_b.pfrb_size))
+			err(1, "pfi_get_ifaces");
+		if (skip_b.pfrb_size <= skip_b.pfrb_msize)
+			break;
+	}
+	return (0);
+}
+
+int
+pfctl_check_skip_ifaces(char *ifname)
+{
+	struct pfi_kif		*p;
+
+	PFRB_FOREACH(p, &skip_b)
+		if ((p->pfik_flags & PFI_IFLAG_SKIP) && !strcmp(ifname, p->pfik_name))
+			p->pfik_flags &= ~PFI_IFLAG_SKIP;
+	return (0);
+}
+
+int
+pfctl_clear_skip_ifaces(struct pfctl *pf)
+{
+	struct pfi_kif		*p;
+
+	PFRB_FOREACH(p, &skip_b)
+		if (p->pfik_flags & PFI_IFLAG_SKIP)
+			pfctl_set_interface_flags(pf, p->pfik_name, PFI_IFLAG_SKIP, 0);
+	return (0);
+}
+
 int
 pfctl_clear_interface_flags(int dev, int opts)
 {
@@ -1479,6 +1521,8 @@ pfctl_rules(int dev, char *filename, int opts, int optimize,
 		else
 			goto _error;
 	}
+	if (loadopt & PFCTL_FLAG_OPTION)
+		pfctl_clear_skip_ifaces(&pf);
 
 	if ((pf.loadopt & PFCTL_FLAG_FILTER &&
 	    (pfctl_load_ruleset(&pf, path, rs, PF_RULESET_SCRUB, 0))) ||
@@ -1889,6 +1933,7 @@ pfctl_set_interface_flags(struct pfctl *pf, char *ifname, int flags, int how)
 		} else {
 			if (ioctl(pf->dev, DIOCSETIFFLAG, &pi))
 				err(1, "DIOCSETIFFLAG");
+			pfctl_check_skip_ifaces(ifname);
 		}
 	}
 	return (0);
@@ -2347,7 +2392,7 @@ main(int argc, char *argv[])
 
 	if ((rulesopt != NULL) && (loadopt & PFCTL_FLAG_OPTION) &&
 	    !anchorname[0])
-		if (pfctl_clear_interface_flags(dev, opts | PF_OPT_QUIET))
+		if (pfctl_get_skip_ifaces())
 			error = 1;
 
 	if (rulesopt != NULL && !(opts & (PF_OPT_MERGE|PF_OPT_NOACTION)) &&