pf: address family must be set when creating a pf_fragment

Fix a panic when handling fragmented ip4 packets with 'drop-ovl' set.
In that scenario we take a different branch in pf_normalize_ip(), taking us to
pf_fragcache() (rather than pf_reassemble()). In pf_fragcache() we create a
pf_fragment, but do not set the address family. This leads to a panic when we
try to insert that into pf_frag_tree because pf_addr_cmp(), which is used to
compare the pf_fragments doesn't know what to do if the address family is not
set.

Simply ensure that the address family is set correctly (always AF_INET in this
path).

PR:			200330
Differential Revision:	https://reviews.freebsd.org/D2769
Approved by:		philip (mentor), gnn (mentor)

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/netpfil/pf/pf_norm.c b/sys/netpfil/pf/pf_norm.c
index 3f210c29df70..3888ef65b2ba 100644
--- a/sys/netpfil/pf/pf_norm.c
+++ b/sys/netpfil/pf/pf_norm.c
@@ -823,6 +823,7 @@ pf_fragcache(struct mbuf **m0, struct ip *h, struct pf_fragment **frag, int mff,
 		(*frag)->fr_max = 0;
 		(*frag)->fr_src.v4 = h->ip_src;
 		(*frag)->fr_dst.v4 = h->ip_dst;
+		(*frag)->fr_af = AF_INET;
 		(*frag)->fr_id = h->ip_id;
 		(*frag)->fr_timeout = time_uptime;