[SCTP]: Discard unauthenticated ASCONF and ASCONF ACK chunks

Now that we support AUTH, discard unauthenticated ASCONF and ASCONF ACK
chunks as mandated in the ADD-IP spec.

Signed-off-by: Vlad Yasevich <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Vlad Yasevich

net/sctp/sm_statefuns.c

@@ -3377,6 +3377,15 @@ sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
 		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
 	}
 
+	/* ADD-IP: Section 4.1.1
+	 * This chunk MUST be sent in an authenticated way by using
+	 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
+	 * is received unauthenticated it MUST be silently discarded as
+	 * described in [I-D.ietf-tsvwg-sctp-auth].
+	 */
+	if (!sctp_addip_noauth && !chunk->auth)
+		return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
+
 	/* Make sure that the ASCONF ADDIP chunk has a valid length.  */
 	if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
 		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
@@ -3463,6 +3472,15 @@ sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
 		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
 	}
 
+	/* ADD-IP, Section 4.1.2:
+	 * This chunk MUST be sent in an authenticated way by using
+	 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
+	 * is received unauthenticated it MUST be silently discarded as
+	 * described in [I-D.ietf-tsvwg-sctp-auth].
+	 */
+	if (!sctp_addip_noauth && !asconf_ack->auth)
+		return sctp_sf_discard_chunk(ep, asoc, type, arg, commands);
+
 	/* Make sure that the ADDIP chunk has a valid length.  */
 	if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
 		return sctp_sf_violation_chunklen(ep, asoc, type, arg,