SCTP : Add paramters validity check for ASCONF chunk

If ADDIP is enabled, when an ASCONF chunk is received with ASCONF
paramter length set to zero, this will cause infinite loop.
By the way, if an malformed ASCONF chunk is received, will cause
processing to access memory without verifying.

This is because of not check the validity of parameters in ASCONF chunk.
This patch fixed this.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index c2fe2dc..490a292 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -421,6 +421,7 @@
  * internally.
  */
 union sctp_addr_param {
+	struct sctp_paramhdr p;
 	struct sctp_ipv4addr_param v4;
 	struct sctp_ipv6addr_param v6;
 };