[NETFILTER]: Fix another crash in ip_nat_pptp
[powerpc.git] / net / ipv4 / netfilter / ip_nat_helper_pptp.c
index 3cdd068..50960cb 100644 (file)
@@ -73,6 +73,7 @@ static void pptp_nat_expected(struct ip_conntrack *ct,
        struct ip_conntrack_tuple t;
        struct ip_ct_pptp_master *ct_pptp_info;
        struct ip_nat_pptp *nat_pptp_info;
+       struct ip_nat_range range;
 
        ct_pptp_info = &master->help.ct_pptp_info;
        nat_pptp_info = &master->nat.help.nat_pptp_info;
@@ -110,7 +111,30 @@ static void pptp_nat_expected(struct ip_conntrack *ct,
                DEBUGP("not found!\n");
        }
 
-       ip_nat_follow_master(ct, exp);
+       /* This must be a fresh one. */
+       BUG_ON(ct->status & IPS_NAT_DONE_MASK);
+
+       /* Change src to where master sends to */
+       range.flags = IP_NAT_RANGE_MAP_IPS;
+       range.min_ip = range.max_ip
+               = ct->master->tuplehash[!exp->dir].tuple.dst.ip;
+       if (exp->dir == IP_CT_DIR_ORIGINAL) {
+               range.flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
+               range.min = range.max = exp->saved_proto;
+       }
+       /* hook doesn't matter, but it has to do source manip */
+       ip_nat_setup_info(ct, &range, NF_IP_POST_ROUTING);
+
+       /* For DST manip, map port here to where it's expected. */
+       range.flags = IP_NAT_RANGE_MAP_IPS;
+       range.min_ip = range.max_ip
+               = ct->master->tuplehash[!exp->dir].tuple.src.ip;
+       if (exp->dir == IP_CT_DIR_REPLY) {
+               range.flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
+               range.min = range.max = exp->saved_proto;
+       }
+       /* hook doesn't matter, but it has to do destination manip */
+       ip_nat_setup_info(ct, &range, NF_IP_PRE_ROUTING);
 }
 
 /* outbound packets == from PNS to PAC */
@@ -124,14 +148,14 @@ pptp_outbound_pkt(struct sk_buff **pskb,
 {
        struct ip_ct_pptp_master *ct_pptp_info = &ct->help.ct_pptp_info;
        struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info;
-
-       u_int16_t msg, *cid = NULL, new_callid;
+       u_int16_t msg, new_callid;
+       unsigned int cid_off;
 
        new_callid = htons(ct_pptp_info->pns_call_id);
        
        switch (msg = ntohs(ctlh->messageType)) {
                case PPTP_OUT_CALL_REQUEST:
-                       cid = &pptpReq->ocreq.callID;
+                       cid_off = offsetof(union pptp_ctrl_union, ocreq.callID);
                        /* FIXME: ideally we would want to reserve a call ID
                         * here.  current netfilter NAT core is not able to do
                         * this :( For now we use TCP source port. This breaks
@@ -148,10 +172,10 @@ pptp_outbound_pkt(struct sk_buff **pskb,
                        ct_pptp_info->pns_call_id = ntohs(new_callid);
                        break;
                case PPTP_IN_CALL_REPLY:
-                       cid = &pptpReq->icreq.callID;
+                       cid_off = offsetof(union pptp_ctrl_union, icreq.callID);
                        break;
                case PPTP_CALL_CLEAR_REQUEST:
-                       cid = &pptpReq->clrreq.callID;
+                       cid_off = offsetof(union pptp_ctrl_union, clrreq.callID);
                        break;
                default:
                        DEBUGP("unknown outbound packet 0x%04x:%s\n", msg,
@@ -173,18 +197,15 @@ pptp_outbound_pkt(struct sk_buff **pskb,
 
        /* only OUT_CALL_REQUEST, IN_CALL_REPLY, CALL_CLEAR_REQUEST pass
         * down to here */
-
-       IP_NF_ASSERT(cid);
-
        DEBUGP("altering call id from 0x%04x to 0x%04x\n",
-               ntohs(*cid), ntohs(new_callid));
+               ntohs(*(u_int16_t *)pptpReq + cid_off), ntohs(new_callid));
 
        /* mangle packet */
        if (ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
-               (void *)cid - ((void *)ctlh - sizeof(struct pptp_pkt_hdr)),
-                                       sizeof(new_callid), 
-                                       (char *)&new_callid,
-                                       sizeof(new_callid)) == 0)
+                                    cid_off + sizeof(struct pptp_pkt_hdr) +
+                                    sizeof(struct PptpControlHeader),
+                                    sizeof(new_callid), (char *)&new_callid,
+                                    sizeof(new_callid)) == 0)
                return NF_DROP;
 
        return NF_ACCEPT;
@@ -213,9 +234,10 @@ pptp_exp_gre(struct ip_conntrack_expect *expect_orig,
 
        /* alter expectation for PNS->PAC direction */
        invert_tuplepr(&inv_t, &expect_orig->tuple);
-       expect_orig->saved_proto.gre.key = htons(nat_pptp_info->pac_call_id);
+       expect_orig->saved_proto.gre.key = htons(ct_pptp_info->pns_call_id);
        expect_orig->tuple.src.u.gre.key = htons(nat_pptp_info->pns_call_id);
        expect_orig->tuple.dst.u.gre.key = htons(ct_pptp_info->pac_call_id);
+       expect_orig->dir = IP_CT_DIR_ORIGINAL;
        inv_t.src.ip = reply_t->src.ip;
        inv_t.dst.ip = reply_t->dst.ip;
        inv_t.src.u.gre.key = htons(nat_pptp_info->pac_call_id);
@@ -233,6 +255,7 @@ pptp_exp_gre(struct ip_conntrack_expect *expect_orig,
        expect_reply->saved_proto.gre.key = htons(nat_pptp_info->pns_call_id);
        expect_reply->tuple.src.u.gre.key = htons(nat_pptp_info->pac_call_id);
        expect_reply->tuple.dst.u.gre.key = htons(ct_pptp_info->pns_call_id);
+       expect_reply->dir = IP_CT_DIR_REPLY;
        inv_t.src.ip = orig_t->src.ip;
        inv_t.dst.ip = orig_t->dst.ip;
        inv_t.src.u.gre.key = htons(nat_pptp_info->pns_call_id);
@@ -273,7 +296,8 @@ pptp_inbound_pkt(struct sk_buff **pskb,
                 union pptp_ctrl_union *pptpReq)
 {
        struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info;
-       u_int16_t msg, new_cid = 0, new_pcid, *pcid = NULL, *cid = NULL;
+       u_int16_t msg, new_cid = 0, new_pcid;
+       unsigned int pcid_off, cid_off = 0;
 
        int ret = NF_ACCEPT, rv;
 
@@ -281,23 +305,23 @@ pptp_inbound_pkt(struct sk_buff **pskb,
 
        switch (msg = ntohs(ctlh->messageType)) {
        case PPTP_OUT_CALL_REPLY:
-               pcid = &pptpReq->ocack.peersCallID;     
-               cid = &pptpReq->ocack.callID;
+               pcid_off = offsetof(union pptp_ctrl_union, ocack.peersCallID);
+               cid_off = offsetof(union pptp_ctrl_union, ocack.callID);
                break;
        case PPTP_IN_CALL_CONNECT:
-               pcid = &pptpReq->iccon.peersCallID;
+               pcid_off = offsetof(union pptp_ctrl_union, iccon.peersCallID);
                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;
+               pcid_off = offsetof(union pptp_ctrl_union, wanerr.peersCallID);
                break;
        case PPTP_CALL_DISCONNECT_NOTIFY:
-               pcid = &pptpReq->disc.callID;
+               pcid_off = offsetof(union pptp_ctrl_union, disc.callID);
                break;
        case PPTP_SET_LINK_INFO:
-               pcid = &pptpReq->setlink.peersCallID;
+               pcid_off = offsetof(union pptp_ctrl_union, setlink.peersCallID);
                break;
 
        default:
@@ -319,25 +343,24 @@ pptp_inbound_pkt(struct sk_buff **pskb,
         * WAN_ERROR_NOTIFY, CALL_DISCONNECT_NOTIFY pass down here */
 
        /* mangle packet */
-       IP_NF_ASSERT(pcid);
        DEBUGP("altering peer call id from 0x%04x to 0x%04x\n",
-               ntohs(*pcid), ntohs(new_pcid));
+               ntohs(*(u_int16_t *)pptpReq + pcid_off), ntohs(new_pcid));
        
-       rv = ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, 
-                                     (void *)pcid - ((void *)ctlh - sizeof(struct pptp_pkt_hdr)),
+       rv = ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
+                                     pcid_off + sizeof(struct pptp_pkt_hdr) +
+                                     sizeof(struct PptpControlHeader),
                                      sizeof(new_pcid), (char *)&new_pcid, 
                                      sizeof(new_pcid));
        if (rv != NF_ACCEPT) 
                return rv;
 
        if (new_cid) {
-               IP_NF_ASSERT(cid);
                DEBUGP("altering call id from 0x%04x to 0x%04x\n",
-                       ntohs(*cid), ntohs(new_cid));
-               rv = ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, 
-                                             (void *)cid - ((void *)ctlh - sizeof(struct pptp_pkt_hdr)), 
-                                             sizeof(new_cid),
-                                             (char *)&new_cid, 
+                       ntohs(*(u_int16_t *)pptpReq + cid_off), ntohs(new_cid));
+               rv = ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
+                                             cid_off + sizeof(struct pptp_pkt_hdr) +
+                                             sizeof(struct PptpControlHeader),
+                                             sizeof(new_cid), (char *)&new_cid, 
                                              sizeof(new_cid));
                if (rv != NF_ACCEPT)
                        return rv;