netfilter: xt_sctp: sctp chunk mapping doesn't work

When user tries to map all chunks given in argument, kernel
works on a copy of the chunkmap, but at the end it doesn't
check the copy, but the orginal one.

Signed-off-by: Qu Haoran <haoran.qu@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/xt_sctp.c b/net/netfilter/xt_sctp.c
index e223cb4..a189ada 100644
--- a/net/netfilter/xt_sctp.c
+++ b/net/netfilter/xt_sctp.c
@@ -105,7 +105,7 @@
 
 	switch (chunk_match_type) {
 	case SCTP_CHUNK_MATCH_ALL:
-		return SCTP_CHUNKMAP_IS_CLEAR(info->chunkmap);
+		return SCTP_CHUNKMAP_IS_CLEAR(chunkmapcopy);
 	case SCTP_CHUNK_MATCH_ANY:
 		return false;
 	case SCTP_CHUNK_MATCH_ONLY: