[NETFILTER]: PPTP conntrack: consolidate header parsing

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/netfilter/ip_conntrack_helper_pptp.c b/net/ipv4/netfilter/ip_conntrack_helper_pptp.c
index 3b5464fa4217ac72349d20c6bac3e9ab0b4606ad..9a98a6ce1901a93433becda2b0e81a5be03f3323 100644 (file)
--- a/net/ipv4/netfilter/ip_conntrack_helper_pptp.c
+++ b/net/ipv4/netfilter/ip_conntrack_helper_pptp.c
@@ -291,60 +291,21 @@ out_unexpect_orig:
        goto out_put_both;
 }
 
-static const unsigned int pptp_msg_size[] = {
-       [PPTP_START_SESSION_REQUEST]  = sizeof(struct PptpStartSessionRequest),
-       [PPTP_START_SESSION_REPLY]    = sizeof(struct PptpStartSessionReply),
-       [PPTP_STOP_SESSION_REQUEST]   = sizeof(struct PptpStopSessionRequest),
-       [PPTP_STOP_SESSION_REPLY]     = sizeof(struct PptpStopSessionReply),
-       [PPTP_OUT_CALL_REQUEST]       = sizeof(struct PptpOutCallRequest),
-       [PPTP_OUT_CALL_REPLY]         = sizeof(struct PptpOutCallReply),
-       [PPTP_IN_CALL_REQUEST]        = sizeof(struct PptpInCallRequest),
-       [PPTP_IN_CALL_REPLY]          = sizeof(struct PptpInCallReply),
-       [PPTP_IN_CALL_CONNECT]        = sizeof(struct PptpInCallConnected),
-       [PPTP_CALL_CLEAR_REQUEST]     = sizeof(struct PptpClearCallRequest),
-       [PPTP_CALL_DISCONNECT_NOTIFY] = sizeof(struct PptpCallDisconnectNotify),
-       [PPTP_WAN_ERROR_NOTIFY]       = sizeof(struct PptpWanErrorNotify),
-       [PPTP_SET_LINK_INFO]          = sizeof(struct PptpSetLinkInfo),
-};
-
 static inline int
 pptp_inbound_pkt(struct sk_buff **pskb,
-                struct tcphdr *tcph,
-                unsigned int nexthdr_off,
-                unsigned int datalen,
+                struct PptpControlHeader *ctlh,
+                union pptp_ctrl_union *pptpReq,
+                unsigned int reqlen,
                 struct ip_conntrack *ct,
                 enum ip_conntrack_info ctinfo)
 {
-       struct PptpControlHeader _ctlh, *ctlh;
-       unsigned int reqlen;
-       union pptp_ctrl_union _pptpReq, *pptpReq;
        struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info;
        u_int16_t msg;
        __be16 cid, pcid;
 
-       ctlh = skb_header_pointer(*pskb, nexthdr_off, sizeof(_ctlh), &_ctlh);
-       if (!ctlh) {
-               DEBUGP("error during skb_header_pointer\n");
-               return NF_ACCEPT;
-       }
-       nexthdr_off += sizeof(_ctlh);
-       datalen -= sizeof(_ctlh);
-
-       reqlen = datalen;
-       if (reqlen > sizeof(*pptpReq))
-               reqlen = sizeof(*pptpReq);
-       pptpReq = skb_header_pointer(*pskb, nexthdr_off, reqlen, &_pptpReq);
-       if (!pptpReq) {
-               DEBUGP("error during skb_header_pointer\n");
-               return NF_ACCEPT;
-       }
-
        msg = ntohs(ctlh->messageType);
        DEBUGP("inbound control message %s\n", pptp_msg_name[msg]);
 
-       if (msg > 0 && msg <= PPTP_MSG_MAX && reqlen < pptp_msg_size[msg])
-               return NF_ACCEPT;
-
        switch (msg) {
        case PPTP_START_SESSION_REPLY:
                /* server confirms new control session */
@@ -480,38 +441,19 @@ pptp_inbound_pkt(struct sk_buff **pskb,
 
 static inline int
 pptp_outbound_pkt(struct sk_buff **pskb,
-                 struct tcphdr *tcph,
-                 unsigned int nexthdr_off,
-                 unsigned int datalen,
+                 struct PptpControlHeader *ctlh,
+                 union pptp_ctrl_union *pptpReq,
+                 unsigned int reqlen,
                  struct ip_conntrack *ct,
                  enum ip_conntrack_info ctinfo)
 {
-       struct PptpControlHeader _ctlh, *ctlh;
-       unsigned int reqlen;
-       union pptp_ctrl_union _pptpReq, *pptpReq;
        struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info;
        u_int16_t msg;
        __be16 cid, pcid;
 
-       ctlh = skb_header_pointer(*pskb, nexthdr_off, sizeof(_ctlh), &_ctlh);
-       if (!ctlh)
-               return NF_ACCEPT;
-       nexthdr_off += sizeof(_ctlh);
-       datalen -= sizeof(_ctlh);
-
-       reqlen = datalen;
-       if (reqlen > sizeof(*pptpReq))
-               reqlen = sizeof(*pptpReq);
-       pptpReq = skb_header_pointer(*pskb, nexthdr_off, reqlen, &_pptpReq);
-       if (!pptpReq)
-               return NF_ACCEPT;
-
        msg = ntohs(ctlh->messageType);
        DEBUGP("outbound control message %s\n", pptp_msg_name[msg]);
 
-       if (msg > 0 && msg <= PPTP_MSG_MAX && reqlen < pptp_msg_size[msg])
-               return NF_ACCEPT;
-
        switch (msg) {
        case PPTP_START_SESSION_REQUEST:
                /* client requests for new control session */
@@ -593,6 +535,21 @@ pptp_outbound_pkt(struct sk_buff **pskb,
        return NF_ACCEPT;
 }
 
+static const unsigned int pptp_msg_size[] = {
+       [PPTP_START_SESSION_REQUEST]  = sizeof(struct PptpStartSessionRequest),
+       [PPTP_START_SESSION_REPLY]    = sizeof(struct PptpStartSessionReply),
+       [PPTP_STOP_SESSION_REQUEST]   = sizeof(struct PptpStopSessionRequest),
+       [PPTP_STOP_SESSION_REPLY]     = sizeof(struct PptpStopSessionReply),
+       [PPTP_OUT_CALL_REQUEST]       = sizeof(struct PptpOutCallRequest),
+       [PPTP_OUT_CALL_REPLY]         = sizeof(struct PptpOutCallReply),
+       [PPTP_IN_CALL_REQUEST]        = sizeof(struct PptpInCallRequest),
+       [PPTP_IN_CALL_REPLY]          = sizeof(struct PptpInCallReply),
+       [PPTP_IN_CALL_CONNECT]        = sizeof(struct PptpInCallConnected),
+       [PPTP_CALL_CLEAR_REQUEST]     = sizeof(struct PptpClearCallRequest),
+       [PPTP_CALL_DISCONNECT_NOTIFY] = sizeof(struct PptpCallDisconnectNotify),
+       [PPTP_WAN_ERROR_NOTIFY]       = sizeof(struct PptpWanErrorNotify),
+       [PPTP_SET_LINK_INFO]          = sizeof(struct PptpSetLinkInfo),
+};
 
 /* track caller id inside control connection, call expect_related */
 static int
@@ -600,16 +557,17 @@ conntrack_pptp_help(struct sk_buff **pskb,
                    struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
 
 {
-       struct pptp_pkt_hdr _pptph, *pptph;
-       struct tcphdr _tcph, *tcph;
-       u_int32_t tcplen = (*pskb)->len - (*pskb)->nh.iph->ihl * 4;
-       u_int32_t datalen;
        int dir = CTINFO2DIR(ctinfo);
        struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info;
-       unsigned int nexthdr_off;
-
+       struct tcphdr _tcph, *tcph;
+       struct pptp_pkt_hdr _pptph, *pptph;
+       struct PptpControlHeader _ctlh, *ctlh;
+       union pptp_ctrl_union _pptpReq, *pptpReq;
+       unsigned int tcplen = (*pskb)->len - (*pskb)->nh.iph->ihl * 4;
+       unsigned int datalen, reqlen, nexthdr_off;
        int oldsstate, oldcstate;
        int ret;
+       u_int16_t msg;
 
        /* don't do any tracking before tcp handshake complete */
        if (ctinfo != IP_CT_ESTABLISHED
@@ -648,6 +606,23 @@ conntrack_pptp_help(struct sk_buff **pskb,
                return NF_ACCEPT;
        }
 
+       ctlh = skb_header_pointer(*pskb, nexthdr_off, sizeof(_ctlh), &_ctlh);
+       if (!ctlh)
+               return NF_ACCEPT;
+       nexthdr_off += sizeof(_ctlh);
+       datalen -= sizeof(_ctlh);
+
+       reqlen = datalen;
+       msg = ntohs(ctlh->messageType);
+       if (msg > 0 && msg <= PPTP_MSG_MAX && reqlen < pptp_msg_size[msg])
+               return NF_ACCEPT;
+       if (reqlen > sizeof(*pptpReq))
+               reqlen = sizeof(*pptpReq);
+
+       pptpReq = skb_header_pointer(*pskb, nexthdr_off, reqlen, &_pptpReq);
+       if (!pptpReq)
+               return NF_ACCEPT;
+
        oldsstate = info->sstate;
        oldcstate = info->cstate;
 
@@ -657,11 +632,11 @@ conntrack_pptp_help(struct sk_buff **pskb,
         * established from PNS->PAC.  However, RFC makes no guarantee */
        if (dir == IP_CT_DIR_ORIGINAL)
                /* client -> server (PNS -> PAC) */
-               ret = pptp_outbound_pkt(pskb, tcph, nexthdr_off, datalen, ct,
+               ret = pptp_outbound_pkt(pskb, ctlh, pptpReq, reqlen, ct,
                                        ctinfo);
        else
                /* server -> client (PAC -> PNS) */
-               ret = pptp_inbound_pkt(pskb, tcph, nexthdr_off, datalen, ct,
+               ret = pptp_inbound_pkt(pskb, ctlh, pptpReq, reqlen, ct,
                                       ctinfo);
        DEBUGP("sstate: %d->%d, cstate: %d->%d\n",
                oldsstate, info->sstate, oldcstate, info->cstate);