avoid endless loop in processipcp, processipv6cp

[l2tpns.git] / ppp.c

diff --git a/ppp.c b/ppp.c
index 0f87c97..1834bd0 100644 (file)
--- a/ppp.c
+++ b/ppp.c
@@ -1,6 +1,6 @@
 // L2TPNS PPP Stuff
 
-char const *cvs_id_ppp = "$Id: ppp.c,v 1.86 2005/11/17 05:24:17 bodea Exp $";
+char const *cvs_id_ppp = "$Id: ppp.c,v 1.95 2006/02/17 14:35:54 bodea Exp $";
 
 #include <stdio.h>
 #include <string.h>
@@ -449,6 +449,7 @@ static void ppp_code_rej(sessionidt s, tunnelidt t, uint16_t proto,
 {
        uint8_t *q;
        int mru = session[s].mru;
+       if (mru < MINMTU) mru = MINMTU;
        if (mru > size) mru = size;
 
        l += 4;
@@ -474,7 +475,6 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 {
        uint8_t b[MAXETHER];
        uint8_t *q = NULL;
-       uint32_t magicno = 0;
        uint16_t hl;
 
        CSTAT(processlcp);
@@ -498,7 +498,9 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        if (session[s].die) // going down...
                return;
 
-       LOG(*p == EchoReq ? 4 : 3, s, t, "LCP: recv %s\n", ppp_code(*p));
+       LOG((*p == EchoReq || *p == EchoReply) ? 4 : 3, s, t,
+               "LCP: recv %s\n", ppp_code(*p));
+
        if (config->debug > 3) dumplcp(p, l);
 
        if (*p == ConfigAck)
@@ -577,9 +579,10 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                case 1: // Maximum-Receive-Unit
                                        {
                                                uint16_t mru = ntohs(*(uint16_t *)(o + 2));
-                                               if (mru >= 576)
+                                               if (mru >= MINMTU)
                                                {
                                                        session[s].mru = mru;
+                                                       cluster_send_session(s);
                                                        break;
                                                }
 
@@ -646,11 +649,8 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                        }
                                        break;
 
-                               case 5: // Magic-Number
-                                       magicno = ntohl(*(uint32_t *)(o + 2));
-                                       break;
-
                                case 4: // Quality-Protocol
+                               case 5: // Magic-Number
                                case 7: // Protocol-Field-Compression
                                case 8: // Address-And-Control-Field-Compression
                                        break;
@@ -791,9 +791,21 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                                        break;
 
+                               case 5: // Magic-Number
+                                       if (*p == ConfigNak)
+                                       {
+                                               session[s].magic = ntohl(*(uint32_t *)(o + 2));
+                                               LOG(3, s, t, "    Remote requested magic-no %x\n", session[s].magic);
+                                               if (!session[s].magic) session[s].magic = time_now; // Netgear DG814 sends zero??
+                                               cluster_send_session(s);
+                                               break;
+                                       }
+                                       // ConfigRej: fallthrough
+
                                default:
                                        LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
-                                       break;
+                                       sessionshutdown(s, "Unable to negotiate LCP.", 3, 0);
+                                       return;
                        }
                        x -= length;
                        o += length;
@@ -1002,11 +1014,13 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                while (length > 2)
                {
+                       if (!o[1] || o[1] > length) return;
+
                        switch (*o)
                        {
                        case 3: // ip address
                                gotip++; // seen address
-                               if (o[1] != 6 || o[1] > length) return;
+                               if (o[1] != 6) return;
 
                                addr = htonl(session[s].ip);
                                if (memcmp(o + 2, &addr, (sizeof addr)))
@@ -1023,7 +1037,7 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                break;
 
                        case 129: // primary DNS
-                               if (o[1] != 6 || o[1] > length) return;
+                               if (o[1] != 6) return;
 
                                addr = htonl(session[s].dns1);
                                if (memcmp(o + 2, &addr, (sizeof addr)))
@@ -1035,9 +1049,9 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                break;
 
                        case 131: // secondary DNS
-                               if (o[1] != 6 || o[1] > length) return;
+                               if (o[1] != 6) return;
 
-                               addr = htonl(session[s].dns1);
+                               addr = htonl(session[s].dns2);
                                if (memcmp(o + 2, &addr, sizeof(addr)))
                                {
                                        q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
@@ -1227,11 +1241,13 @@ void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                while (length > 2)
                {
+                       if (!o[1] || o[1] > length) return;
+
                        switch (*o)
                        {
                        case 1: // interface identifier
                                gotip++; // seen address
-                               if (o[1] != 10 || o[1] > length) return;
+                               if (o[1] != 10) return;
 
                                *(uint32_t *) ident = htonl(session[s].ip);
                                *(uint32_t *) (ident + 4) = 0;
@@ -1754,9 +1770,7 @@ uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelid
 {
        if (size < 12) // Need more space than this!!
        {
-               static int backtrace_count = 0;
                LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
-               log_backtrace(backtrace_count, 5)
                return NULL;
        }
 
@@ -1779,9 +1793,7 @@ uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelid
 
        if (l + 12 > size)
        {
-               static int backtrace_count = 0;
                LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
-               log_backtrace(backtrace_count, 5)
                return NULL;
        }
 
@@ -1877,3 +1889,33 @@ void sendccp(sessionidt s, tunnelidt t)
        tunnelsend(b, (q - b) + 4 , t);
        restart_timer(s, ccp);
 }
+
+// Reject unknown/unconfigured protocols
+void protoreject(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l, uint16_t proto)
+{
+
+       uint8_t buf[MAXETHER];
+       uint8_t *q;
+       int mru = session[s].mru;
+       if (mru < MINMTU) mru = MINMTU;
+       if (mru > sizeof(buf)) mru = sizeof(buf);
+
+       l += 6;
+       if (l > mru) l = mru;
+
+       q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPLCP);
+       if (!q) return;
+
+       *q = ProtocolRej;
+       *(q + 1) = ++sess_local[s].lcp_ident;
+       *(uint16_t *)(q + 2) = htons(l);
+       *(uint16_t *)(q + 4) = htons(proto);
+       memcpy(q + 6, p, l - 6);
+
+       if (proto == PPPIPV6CP)
+               LOG(3, s, t, "LCP: send ProtocolRej (IPV6CP: not configured)\n");
+       else
+               LOG(2, s, t, "LCP: sent ProtocolRej (0x%04X: unsupported)\n", proto);
+
+       tunnelsend(buf, l + (q - buf), t);
+}