Re: npf bug(?)

[Tom Ivar Helbekkmo <tih%hamartun.priv.no@localhost>]

6bone%6bone.informatik.uni-leipzig.de@localhost writes:

> Thanks for the patch. Unfortunately, I could not apply it to -7. I've
> tested -current. The problem seems to be solved.

Here it is, adjusted for the "netbsd-7" cvs tag:

--- sys/net/npf/npf_handler.c~	2017-03-30 17:26:49.458901595 +0200
+++ sys/net/npf/npf_handler.c	2017-03-30 17:29:52.833241529 +0200
@@ -146,7 +146,7 @@
 	npf_conn_t *con;
 	npf_rule_t *rl;
 	npf_rproc_t *rp;
-	int error, retfl;
+	int error, retfl, flags;
 	int decision;
 
 	/*
@@ -164,9 +164,17 @@
 	rp = NULL;
 
 	/* Cache everything.  Determine whether it is an IP fragment. */
-	if (__predict_false(npf_cache_all(&npc) & NPC_IPFRAG)) {
+	flags = npf_cache_all(&npc);
+	if (__predict_false(flags & NPC_IPFRAG)) {
 		/*
-		 * Pass to IPv4 or IPv6 reassembly mechanism.
+		 * We pass IPv6 fragments unconditionally
+		 * The first IPv6 fragment is not marked as such
+		 * and passes through the filter
+		 */
+		if (flags & NPC_IP6)
+			return 0;
+		/*
+		 * Pass to IPv4 reassembly mechanism.
 		 */
 		error = npf_reassembly(&npc, mp);
 		if (error) {
--- sys/net/npf/npf_inet.c~	2017-03-30 17:27:07.661343255 +0200
+++ sys/net/npf/npf_inet.c	2017-03-30 17:30:45.721564537 +0200
@@ -352,6 +352,7 @@
 	case (IPV6_VERSION >> 4): {
 		struct ip6_hdr *ip6;
 		struct ip6_ext *ip6e;
+		struct ip6_frag *ip6f;
 		size_t off, hlen;
 
 		ip6 = nbuf_ensure_contig(nbuf, sizeof(struct ip6_hdr));
@@ -384,8 +385,21 @@
 				hlen = (ip6e->ip6e_len + 1) << 3;
 				break;
 			case IPPROTO_FRAGMENT:
+				ip6f = nbuf_ensure_contig(nbuf, sizeof(*ip6f));
+				if (ip6f == NULL)
+					return 0;
+				/*
+				 * We treat the first fragment as a regular
+				 * packet and then we pass the rest of the
+				 * fragments unconditionally. This way if
+				 * the first packet passes the rest will
+				 * be able to reassembled, if not they will
+				 * be ignored. We can do better later.
+				 */
+				if (ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK) != 0)
+					flags |= NPC_IPFRAG;
+
 				hlen = sizeof(struct ip6_frag);
-				flags |= NPC_IPFRAG;
 				break;
 			case IPPROTO_AH:
 				hlen = (ip6e->ip6e_len + 2) << 2;


-tih
-- 
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