X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/46ec025f156b16cf4bd65270680ffb69313aea18..bf06c59c60609212d21914c6d130cb28f900baf3:/l2tpns.c?ds=inline

diff --git a/l2tpns.c b/l2tpns.c
index f49586b..a28cd5f 100644
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -4,7 +4,7 @@
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 
-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.82 2005/02/09 00:16:17 bodea Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.85 2005/03/10 03:08:08 bodea Exp $";
 
 #include <arpa/inet.h>
 #include <assert.h>
@@ -187,7 +187,7 @@ static int remove_plugin(char *plugin_name);
 static void plugins_done(void);
 static void processcontrol(uint8_t *buf, int len, struct sockaddr_in *addr, int alen);
 static tunnelidt new_tunnel(void);
-static int unhide_avp(uint8_t *avp, tunnelidt t, sessionidt s, uint16_t length);
+static void unhide_value(uint8_t *value, size_t len, uint16_t type, uint8_t *vector, size_t vec_len);
 
 // return internal time (10ths since process startup)
 static clockt now(void)
@@ -660,7 +660,7 @@ sessionidt sessionbyip(in_addr_t ip)
 	int s = lookup_ipmap(ip);
 	CSTAT(sessionbyip);
 
-	if (s > 0 && s < MAXSESSION && session[s].tunnel)
+	if (s > 0 && s < MAXSESSION && session[s].opened)
 		return (sessionidt) s;
 
 	return 0;
@@ -679,7 +679,7 @@ sessionidt sessionbyipv6(struct in6_addr ip)
 		s = lookup_ipv6map(ip);
 	}
 
-	if (s > 0 && s < MAXSESSION && session[s].tunnel)
+	if (s > 0 && s < MAXSESSION && session[s].opened)
 		return s;
 
 	return 0;
@@ -815,8 +815,11 @@ sessionidt sessionbyuser(char *username)
 	int s;
 	CSTAT(sessionbyuser);
 
-	for (s = 1; s < MAXSESSION ; ++s)
+	for (s = 1; s <= config->cluster_highest_sessionid ; ++s)
 	{
+		if (!session[s].opened)
+			continue;
+
 		if (session[s].walled_garden)
 			continue;		// Skip walled garden users.
 
@@ -858,17 +861,16 @@ void send_garp(in_addr_t ip)
 	sendarp(ifr.ifr_ifindex, mac, ip);
 }
 
-// Find session by username, 0 for not found
 static sessiont *sessiontbysessionidt(sessionidt s)
 {
-	if (!s || s > MAXSESSION) return NULL;
+	if (!s || s >= MAXSESSION) return NULL;
 	return &session[s];
 }
 
 static sessionidt sessionidtbysessiont(sessiont *s)
 {
 	sessionidt val = s-session;
-	if (s < session || val > MAXSESSION) return 0;
+	if (s < session || val >= MAXSESSION) return 0;
 	return val;
 }
 
@@ -1357,7 +1359,7 @@ static void controladd(controlt * c, tunnelidt t, sessionidt s)
 //
 void throttle_session(sessionidt s, int rate_in, int rate_out)
 {
-	if (!session[s].tunnel)
+	if (!session[s].opened)
 		return; // No-one home.
 
 	if (!*session[s].user)
@@ -1395,7 +1397,7 @@ void throttle_session(sessionidt s, int rate_in, int rate_out)
 // add/remove filters from session (-1 = no change)
 static void filter_session(sessionidt s, int filter_in, int filter_out)
 {
-	if (!session[s].tunnel)
+	if (!session[s].opened)
 		return; // No-one home.
 
 	if (!*session[s].user)
@@ -1438,9 +1440,9 @@ void sessionshutdown(sessionidt s, char *reason)
 
 	CSTAT(sessionshutdown);
 
-	if (!session[s].tunnel)
+	if (!session[s].opened)
 	{
-		LOG(3, s, session[s].tunnel, "Called sessionshutdown on a session with no tunnel.\n");
+		LOG(3, s, session[s].tunnel, "Called sessionshutdown on an unopened session.\n");
 		return;                   // not a live session
 	}
 
@@ -1451,7 +1453,7 @@ void sessionshutdown(sessionidt s, char *reason)
 		run_plugins(PLUGIN_KILL_SESSION, &data);
 	}
 
-	if (session[s].opened && !walled_garden && !session[s].die)
+	if (!walled_garden && !session[s].die)
 	{
 		// RADIUS Stop message
 		uint16_t r = session[s].radius;
@@ -1514,7 +1516,7 @@ void sessionshutdown(sessionidt s, char *reason)
 	}
 
 	if (!session[s].die)
-		session[s].die = now() + 150; // Clean up in 15 seconds
+		session[s].die = TIME + 150; // Clean up in 15 seconds
 
 	// update filter refcounts
 	if (session[s].filter_in) ip_filters[session[s].filter_in - 1].used--;
@@ -1589,12 +1591,21 @@ void sendipcp(tunnelidt t, sessionidt s)
 }
 
 // kill a session now
-static void sessionkill(sessionidt s, char *reason)
+void sessionkill(sessionidt s, char *reason)
 {
 
 	CSTAT(sessionkill);
 
-	session[s].die = now();
+	if (!session[s].opened) // not alive
+		return;
+
+	if (session[s].next)
+	{
+		LOG(0, s, session[s].tunnel, "Tried to kill a session with next pointer set (%d)\n", session[s].next);
+		return;
+	}
+
+	session[s].die = TIME;
 	sessionshutdown(s, reason);  // close radius/routes, etc.
 	if (session[s].radius)
 		radiusclear(session[s].radius, s); // cant send clean accounting data, session is killed
@@ -1636,7 +1647,7 @@ static void tunnelkill(tunnelidt t, char *reason)
 		controlfree = c;
 	}
 	// kill sessions
-	for (s = 1; s < MAXSESSION; s++)
+	for (s = 1; s <= config->cluster_highest_sessionid ; ++s)
 		if (session[s].tunnel == t)
 			sessionkill(s, reason);
 
@@ -1663,12 +1674,12 @@ static void tunnelshutdown(tunnelidt t, char *reason)
 	LOG(1, 0, t, "Shutting down tunnel %d (%s)\n", t, reason);
 
 	// close session
-	for (s = 1; s < MAXSESSION; s++)
+	for (s = 1; s <= config->cluster_highest_sessionid ; ++s)
 		if (session[s].tunnel == t)
 			sessionshutdown(s, reason);
 
 	tunnel[t].state = TUNNELDIE;
-	tunnel[t].die = now() + 700; // Clean up in 70 seconds
+	tunnel[t].die = TIME + 700; // Clean up in 70 seconds
 	cluster_send_tunnel(t);
 	// TBA - should we wait for sessions to stop?
 	{                            // Send StopCCN
@@ -1750,7 +1761,7 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
 	{                          // control
 		uint16_t message = 0xFFFF;	// message type
 		uint8_t fatal = 0;
-		uint8_t mandatorymessage = 0;
+		uint8_t mandatory = 0;
 		uint8_t chap = 0;		// if CHAP being used
 		uint16_t asession = 0;		// assigned session
 		uint32_t amagic = 0;		// magic number
@@ -1766,7 +1777,10 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
 			return;
 		}
 
-		if ((*buf & 0xCA) != 0xC8)
+		// control messages must have bits 0x80|0x40|0x08
+		// (type, length and sequence) set, and bits 0x02|0x01
+		// (offset and priority) clear
+		if ((*buf & 0xCB) != 0xC8)
 		{
 			LOG(1, s, t, "Bad control header %02X\n", *buf);
 			STAT(tunnel_rx_errors);
@@ -1877,23 +1891,42 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
 		if (l)
 		{                     // if not a null message
 			// process AVPs
-			while (l && !(fatal & 0x80))
+			while (l && !(fatal & 0x80)) // 0x80 = mandatory AVP
 			{
 				uint16_t n = (ntohs(*(uint16_t *) p) & 0x3FF);
 				uint8_t *b = p;
 				uint8_t flags = *p;
 				uint16_t mtype;
-				p += n;       // next
-				if (l < n)
+				if (n > l)
 				{
 					LOG(1, s, t, "Invalid length in AVP\n");
 					STAT(tunnel_rx_errors);
-					fatal = flags;
 					return;
 				}
+				p += n;       // next
 				l -= n;
+				if (flags & 0x3C) // reserved bits, should be clear
+				{
+					LOG(1, s, t, "Unrecognised AVP flags %02X\n", *b);
+					fatal = flags;
+					continue; // next
+				}
+				b += 2;
+				if (*(uint16_t *) (b))
+				{
+					LOG(2, s, t, "Unknown AVP vendor %d\n", ntohs(*(uint16_t *) (b)));
+					fatal = flags;
+					continue; // next
+				}
+				b += 2;
+				mtype = ntohs(*(uint16_t *) (b));
+				b += 2;
+				n -= 6;
+
 				if (flags & 0x40)
 				{
+					uint16_t orig_len;
+
 					// handle hidden AVPs
 					if (!*config->l2tpsecret)
 					{
@@ -1907,40 +1940,36 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
 						fatal = flags;
 						continue;
 					}
+					if (n < 8)
+					{
+						LOG(2, s, t, "Short hidden AVP.\n");
+						fatal = flags;
+						continue;
+					}
+
 					LOG(4, s, t, "Hidden AVP\n");
+
 					// Unhide the AVP
-					n = unhide_avp(b, t, s, n);
-					if (n == 0)
+					unhide_value(b, n, mtype, session[s].random_vector, session[s].random_vector_length);
+
+					orig_len = ntohs(*(uint16_t *) b);
+					if (orig_len > n + 2)
 					{
 						fatal = flags;
 						continue;
 					}
+
+					b += 2;
+					n = orig_len;
 				}
-				if (*b & 0x3C)
-				{
-					LOG(1, s, t, "Unrecognised AVP flags %02X\n", *b);
-					fatal = flags;
-					continue; // next
-				}
-				b += 2;
-				if (*(uint16_t *) (b))
-				{
-					LOG(2, s, t, "Unknown AVP vendor %d\n", ntohs(*(uint16_t *) (b)));
-					fatal = flags;
-					continue; // next
-				}
-				b += 2;
-				mtype = ntohs(*(uint16_t *) (b));
-				b += 2;
-				n -= 6;
 
 				LOG(4, s, t, "   AVP %d (%s) len %d\n", mtype, avp_name(mtype), n);
 				switch (mtype)
 				{
 				case 0:     // message type
 					message = ntohs(*(uint16_t *) b);
+					mandatory = flags & 0x80;
 					LOG(4, s, t, "   Message type = %d (%s)\n", *b, l2tp_message_type(message));
-					mandatorymessage = flags;
 					break;
 				case 1:     // result code
 					{
@@ -2202,7 +2231,8 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
 					if (!sessionfree)
 					{
 						STAT(session_overflow);
-						tunnelshutdown(t, "No free sessions");
+						LOG(1, 0, t, "No free sessions");
+						return;
 					}
 					else
 					{
@@ -2226,7 +2256,7 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
 
 						c = controlnew(11); // sending ICRP
 						session[s].id = sessionid++;
-						session[s].opened = time(NULL);
+						session[s].opened = time_now;
 						session[s].tunnel = t;
 						session[s].far = asession;
 						session[s].last_packet = time_now;
@@ -2264,8 +2294,8 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
 					break;
 				default:
 					STAT(tunnel_rx_errors);
-					if (mandatorymessage & 0x80)
-						tunnelshutdown(t, "Unknown message");
+					if (mandatory)
+						tunnelshutdown(t, "Unknown message type");
 					else
 						LOG(1, s, t, "Unknown message type %d\n", message);
 					break;
@@ -2306,7 +2336,7 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
 			l -= 2;
 		}
 
-		if (s && !session[s].tunnel)	// Is something wrong??
+		if (s && !session[s].opened)	// Is something wrong??
 		{
 			if (!config->cluster_iam_master)
 			{
@@ -2316,9 +2346,7 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
 			}
 
 
-			LOG(1, s, t, "UDP packet contains session %d but no session[%d].tunnel "
-				     "exists (LAC said tunnel = %d).  Dropping packet.\n", s, s, t);
-
+			LOG(1, s, t, "UDP packet contains session which is not opened.  Dropping packet.\n");
 			STAT(tunnel_rx_errors);
 			return;
 		}
@@ -2525,7 +2553,7 @@ static int regular_cleanups(void)
 		if (s > config->cluster_highest_sessionid)
 			s = 1;
 
-		if (!session[s].tunnel)	// Session isn't in use
+		if (!session[s].opened)	// Session isn't in use
 			continue;
 
 		if (!session[s].die && session[s].ip && !(session[s].flags & SF_IPCP_ACKED))
@@ -3134,7 +3162,7 @@ static void initdata(int optdebug, char *optconfig)
 	memset(ip_address_pool, 0, sizeof(ippoolt) * MAXIPPOOL);
 
 		// Put all the sessions on the free list marked as undefined.
-	for (i = 1; i < MAXSESSION - 1; i++)
+	for (i = 1; i < MAXSESSION; i++)
 	{
 		session[i].next = i + 1;
 		session[i].tunnel = T_UNDEF;	// mark it as not filled in.
@@ -3143,7 +3171,7 @@ static void initdata(int optdebug, char *optconfig)
 	sessionfree = 1;
 
 		// Mark all the tunnels as undefined (waiting to be filled in by a download).
-	for (i = 1; i < MAXTUNNEL- 1; i++)
+	for (i = 1; i < MAXTUNNEL; i++)
 		tunnel[i].state = TUNNELUNDEF;	// mark it as not filled in.
 
 	if (!*hostname)
@@ -3269,8 +3297,9 @@ void rebuild_address_pool(void)
 	for (i = 0; i < MAXSESSION; ++i)
 	{
 		int ipid;
-		if (!session[i].ip || !session[i].tunnel)
+		if (!(session[i].opened && session[i].ip))
 			continue;
+
 		ipid = - lookup_ipmap(htonl(session[i].ip));
 
 		if (session[i].ip_pool_index < 0)
@@ -4016,7 +4045,7 @@ int sessionsetup(tunnelidt t, sessionidt s)
 
 	LOG(3, s, t, "Doing session setup for session\n");
 
-	if (!session[s].ip || session[s].ip == 0xFFFFFFFE)
+	if (!session[s].ip)
 	{
 		assign_ip_address(s);
 		if (!session[s].ip)
@@ -4619,7 +4648,7 @@ void become_master(void)
 	{
 		for (s = 1; s <= config->cluster_highest_sessionid ; ++s)
 		{
-			if (!session[s].tunnel) // Not an in-use session.
+			if (!session[s].opened) // Not an in-use session.
 				continue;
 
 			run_plugins(PLUGIN_NEW_SESSION_MASTER, &session[s]);
@@ -4651,7 +4680,7 @@ int cmd_show_hist_idle(struct cli_def *cli, char *command, char **argv, int argc
 	for (s = 1; s <= config->cluster_highest_sessionid ; ++s)
 	{
 		int idle;
-		if (!session[s].tunnel)
+		if (!session[s].opened)
 			continue;
 
 		idle = time_now - session[s].last_packet;
@@ -4689,7 +4718,7 @@ int cmd_show_hist_open(struct cli_def *cli, char *command, char **argv, int argc
 	for (s = 1; s <= config->cluster_highest_sessionid ; ++s)
 	{
 		int open = 0, d;
-		if (!session[s].tunnel)
+		if (!session[s].opened)
 			continue;
 
 		d = time_now - session[s].opened;
@@ -4716,75 +4745,45 @@ int cmd_show_hist_open(struct cli_def *cli, char *command, char **argv, int argc
 
 /* Unhide an avp.
  *
- * This unencodes the AVP using the L2TP CHAP secret and the
- * previously stored random vector. It replaces the hidden data with
- * the cleartext data and returns the length of the cleartext data
- * (including the AVP "header" of 6 bytes).
- *
- * Based on code from rp-l2tpd by Roaring Penguin Software Inc.
+ * This unencodes the AVP using the L2TP secret and the previously
+ * stored random vector.  It overwrites the hidden data with the
+ * unhidden AVP subformat.
  */
-static int unhide_avp(uint8_t *avp, tunnelidt t, sessionidt s, uint16_t length)
+static void unhide_value(uint8_t *value, size_t len, uint16_t type, uint8_t *vector, size_t vec_len)
 {
 	MD5_CTX ctx;
-	uint8_t *cursor;
 	uint8_t digest[16];
-	uint8_t working_vector[16];
-	uint16_t hidden_length;
-	uint8_t type[2];
-	size_t done, todo;
-	uint8_t *output;
-
-	// Find the AVP type.
-	type[0] = *(avp + 4);
-	type[1] = *(avp + 5);
-
-	// Line up with the hidden data
-	cursor = output = avp + 6;
+	uint8_t *last;
+	size_t d = 0;
 
 	// Compute initial pad
 	MD5Init(&ctx);
-	MD5Update(&ctx, type, 2);
+	MD5Update(&ctx, (uint8_t) (type >> 8) & 0xff, 1);
+	MD5Update(&ctx, (uint8_t)  type       & 0xff, 1);
 	MD5Update(&ctx, config->l2tpsecret, strlen(config->l2tpsecret));
-	MD5Update(&ctx, session[s].random_vector, session[s].random_vector_length);
+	MD5Update(&ctx, vector, vec_len);
 	MD5Final(digest, &ctx);
 
-	// Get hidden length
-	hidden_length = ((uint16_t) (digest[0] ^ cursor[0])) * 256 + (uint16_t) (digest[1] ^ cursor[1]);
+	// pointer to last decoded 16 octets
+	last = value;
 
-	// Keep these for later use
-	working_vector[0] = *cursor;
-	working_vector[1] = *(cursor + 1);
-	cursor += 2;
-
-	if (hidden_length > length - 8)
-	{
-		LOG(1, s, t, "Hidden length %d too long in AVP of length %d\n", (int) hidden_length, (int) length);
-		return 0;
-	}
-
-	/* Decrypt remainder */
-	done = 2;
-	todo = hidden_length;
-	while (todo)
+	while (len > 0)
 	{
-		working_vector[done] = *cursor;
-		*output = digest[done] ^ *cursor;
-		++output;
-		++cursor;
-		--todo;
-		++done;
-		if (done == 16 && todo)
+		// calculate a new pad based on the last decoded block
+		if (d >= sizeof(digest))
 		{
-			// Compute new digest
-			done = 0;
 			MD5Init(&ctx);
 			MD5Update(&ctx, config->l2tpsecret, strlen(config->l2tpsecret));
-			MD5Update(&ctx, &working_vector, 16);
+			MD5Update(&ctx, last, sizeof(digest));
 			MD5Final(digest, &ctx);
+
+			d = 0;
+			last = value;
 		}
-	}
 
-	return hidden_length + 6;
+		*value++ ^= digest[d++];
+		len--;
+	}
 }
 
 static int ip_filter_port(ip_filter_portt *p, uint16_t port)