git: ff76ec3e9b28 - main - pf: be more robust against interface name conflicts

The branch main has been updated by kp:

URL: https://cgit.FreeBSD.org/src/commit/?id=ff76ec3e9b287df9378f09ce29eca668162903f4

commit ff76ec3e9b287df9378f09ce29eca668162903f4
Author:     Kristof Provost <kp@FreeBSD.org>
AuthorDate: 2026-04-20 09:22:13 +0000
Commit:     Kristof Provost <kp@FreeBSD.org>
CommitDate: 2026-04-20 12:50:40 +0000

    pf: be more robust against interface name conflicts
    
    pf assumes that interface names are unique (and share a namespace with
    interface group names).
    Unfortunately the FreeBSD network stack has a few edge cases where this
    assumption can be violated. Try to be more robust against this: rather
    than changing the association between a kif and ifp just ignore the next
    interface with the same name.
    
    Sponsored by:   Rubicon Communications, LLC ("Netgate")
---
 sys/netpfil/pf/pf_if.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sys/netpfil/pf/pf_if.c b/sys/netpfil/pf/pf_if.c
index 5288de3d78a0..507879004b17 100644
--- a/sys/netpfil/pf/pf_if.c
+++ b/sys/netpfil/pf/pf_if.c
@@ -498,8 +498,15 @@ pfi_attach_ifnet(struct ifnet *ifp, struct pfi_kkif *kif)
 
 	V_pfi_update++;
 	kif = pfi_kkif_attach(kif, ifp->if_xname);
+	if (kif->pfik_ifp != NULL && kif->pfik_ifp != ifp) {
+		/* Try to not panic later. */
+		printf("WARNING: pf: duplicate interface name detected: %s\n",
+		    if_name(ifp));
+		return;
+	}
 	if_ref(ifp);
 	kif->pfik_ifp = ifp;
+	MPASS(ifp->if_pf_kif == NULL);
 	ifp->if_pf_kif = kif;
 	pfi_kkif_update(kif);
 }