diff options
| -rw-r--r-- | net/ipv4/netfilter/ip_nat_helper_pptp.c | 57 |
1 files changed, 27 insertions, 30 deletions
diff --git a/net/ipv4/netfilter/ip_nat_helper_pptp.c b/net/ipv4/netfilter/ip_nat_helper_pptp.c index 8ad7b36e242..50960cb681f 100644 --- a/net/ipv4/netfilter/ip_nat_helper_pptp.c +++ b/net/ipv4/netfilter/ip_nat_helper_pptp.c @@ -148,14 +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 @@ -172,10 +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, @@ -197,18 +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; @@ -299,7 +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; @@ -307,23 +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 */ 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: @@ -345,25 +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; |