[NETFILTER]: PPTP conntrack: fix header definitions

Fix a few header definitions to match RFC2637. Most importantly the
PptpOutCallRequest header included an invalid padding field and a
size check was disabled because of this.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter_ipv4/ip_conntrack_pptp.h

@@ -107,8 +107,7 @@ struct PptpControlHeader {
 
 struct PptpStartSessionRequest {
 	__be16	protocolVersion;
-	__u8	reserved1;
-	__u8	reserved2;
+	__u16	reserved1;
 	__be32	framingCapability;
 	__be32	bearerCapability;
 	__be16	maxChannels;
@@ -143,6 +142,8 @@ struct PptpStartSessionReply {
 
 struct PptpStopSessionRequest {
 	__u8	reason;
+	__u8	reserved1;
+	__u16	reserved2;
 };
 
 /* PptpStopSessionResultCode */
@@ -152,6 +153,7 @@ struct PptpStopSessionRequest {
 struct PptpStopSessionReply {
 	__u8	resultCode;
 	__u8	generalErrorCode;
+	__u16	reserved1;
 };
 
 struct PptpEchoRequest {
@@ -188,9 +190,8 @@ struct PptpOutCallRequest {
 	__be32	framingType;
 	__be16	packetWindow;
 	__be16	packetProcDelay;
-	__u16	reserved1;
 	__be16	phoneNumberLength;
-	__u16	reserved2;
+	__u16	reserved1;
 	__u8	phoneNumber[64];
 	__u8	subAddress[64];
 };

net/ipv4/netfilter/ip_conntrack_helper_pptp.c

@@ -569,7 +569,7 @@ pptp_outbound_pkt(struct sk_buff **pskb,
 	case PPTP_OUT_CALL_REQUEST:
 		if (reqlen < sizeof(_pptpReq.ocreq)) {
 			DEBUGP("%s: short packet\n", pptp_msg_name[msg]);
-			/* FIXME: break; */
+			break;
 		}
 
 		/* client initiating connection to server */