[patch 5/6] [NETFILTER]: Fix crash in ip_nat_pptp (CVE-2006-0036)

[Greg KH]

-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Patrick McHardy <kaber@xxxxxxxxx>

When an inbound PPTP_IN_CALL_REQUEST packet is received the
PPTP NAT helper uses a NULL pointer in pointer arithmentic to
calculate the offset in the packet which needs to be mangled
and corrupts random memory or crashes.

Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 net/ipv4/netfilter/ip_nat_helper_pptp.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-2.6.14.6.orig/net/ipv4/netfilter/ip_nat_helper_pptp.c
+++ linux-2.6.14.6/net/ipv4/netfilter/ip_nat_helper_pptp.c
@@ -313,7 +313,7 @@ pptp_inbound_pkt(struct sk_buff **pskb,
 		break;
 	case PPTP_IN_CALL_REQUEST:
 		/* only need to nat in case PAC is behind NAT box */
-		break;
+		return NF_ACCEPT;
 	case PPTP_WAN_ERROR_NOTIFY:
 		pcid = &pptpReq->wanerr.peersCallID;
 		break;

--
-
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