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Commit f2ad52c9 authored by Holger Eitzenberger's avatar Holger Eitzenberger Committed by David S. Miller
Browse files

[NETFILTER]: Fix CID offset bug in PPTP NAT helper debug message 



The recent (kernel 2.6.15.1) fix for PPTP NAT helper introduced a
bug - which only appears if DEBUGP is enabled though.

The calculation of the CID offset into a PPTP request struct is
not correct, so that at least not the correct CID is displayed
if DEBUGP is enabled.

This patch corrects CID offset calculation and introduces a #define
for that.

Signed-off-by: default avatarHolger Eitzenberger <heitzenberger@astaro.com>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 77ff72d5

net/ipv4/netfilter/ip_nat_helper_pptp.c

+5 −3
Original line number Diff line number Diff line
@@ -52,6 +52,8 @@ 


#define IP_NAT_PPTP_VERSION "3.0"



#define REQ_CID(req, off)		(*(u_int16_t *)((char *)(req) + (off)))



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");

MODULE_DESCRIPTION("Netfilter NAT helper module for PPTP");
@@ -198,7 +200,7 @@ pptp_outbound_pkt(struct sk_buff **pskb, 
	/* only OUT_CALL_REQUEST, IN_CALL_REPLY, CALL_CLEAR_REQUEST pass

	 * down to here */

	DEBUGP("altering call id from 0x%04x to 0x%04x\n",

		ntohs(*(u_int16_t *)pptpReq + cid_off), ntohs(new_callid));

		ntohs(REQ_CID(pptpReq, cid_off)), ntohs(new_callid));



	/* mangle packet */

	if (ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
@@ -342,7 +344,7 @@ pptp_inbound_pkt(struct sk_buff **pskb, 


	/* mangle packet */

	DEBUGP("altering peer call id from 0x%04x to 0x%04x\n",

		ntohs(*(u_int16_t *)pptpReq + pcid_off), ntohs(new_pcid));

		ntohs(REQ_CID(pptpReq, pcid_off)), ntohs(new_pcid));



	if (ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,

	                             pcid_off + sizeof(struct pptp_pkt_hdr) +
@@ -353,7 +355,7 @@ pptp_inbound_pkt(struct sk_buff **pskb, 


	if (new_cid) {

		DEBUGP("altering call id from 0x%04x to 0x%04x\n",

			ntohs(*(u_int16_t *)pptpReq + cid_off), ntohs(new_cid));

			ntohs(REQ_CID(pptpReq, cid_off)), ntohs(new_cid));

		if (ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,

		                             cid_off + sizeof(struct pptp_pkt_hdr) +

					     sizeof(struct PptpControlHeader),