[net] Move found host caching into net_main

This unifies all the checks and plugs a set of potential buffer
overflows.

include/netmain.h

@@ -262,8 +262,9 @@ typedef struct {
 	netadr_t addr;
 } hostcache_t;
 
-extern int hostCacheCount;
+void NET_AddCachedHost (const char *name, const char *map, const char *cname,
-extern hostcache_t hostcache[HOSTCACHESIZE];
+						int users, int maxusers, int driver, int ldriver,
+						const netadr_t *addr);
 
 extern	double		net_time;
 extern	struct msg_s *net_message;

libs/net/net_main.c

@@ -97,9 +97,11 @@ qboolean    recording = false;
 
 int         net_driverlevel;
 
-
 double      net_time;
 
+static int         hostCacheCount = 0;
+static hostcache_t hostcache[HOSTCACHESIZE];
+
 double
 SetNetTime (void)
 {
@@ -265,6 +267,58 @@ PrintSlistHeader (void)
 	slistLastShown = 0;
 }
 
+void
+NET_AddCachedHost (const char *name, const char *map, const char *cname,
+				   int users, int maxusers, int driver, int ldriver,
+				   const netadr_t *addr)
+{
+	if (hostCacheCount == HOSTCACHESIZE) {
+		return;
+	}
+	for (int i = 0; i < hostCacheCount; i++) {
+		// addr will be 0 for loopback, and there can be only one loopback
+		// server.
+		if (!addr || !memcmp (addr, &hostcache[i].addr, sizeof (netadr_t))) {
+			return;
+		}
+	}
+
+	const int   namesize = sizeof (hostcache[0].name) - 1;
+	const int   mapsize = sizeof (hostcache[0].map) - 1;
+	const int   cnamesize = sizeof (hostcache[0].cname) - 1;
+
+	hostcache_t *host = &hostcache[hostCacheCount++];
+	strncpy (host->name, name, namesize);
+	strncpy (host->map, map, mapsize);
+	strncpy (host->cname, cname, cnamesize);
+	host->name[namesize] = 0;
+	host->map[mapsize] = 0;
+	host->cname[cnamesize] = 0;
+
+	host->users = users;
+	host->maxusers = maxusers;
+	host->driver = driver;
+	host->ldriver = ldriver;
+	if (addr) {
+		host->addr = *addr;
+	} else {
+		memset (&host->addr, 0, sizeof (host->addr));
+	}
+
+	// check for and resolve name conflicts
+	for (int i = 0; i < hostCacheCount - 1; i++) {
+		if (strcasecmp (host->name, hostcache[i].name) == 0) {
+			int         len = strlen (host->name);
+			if (len < namesize && host->name[len - 1] > '8') {
+				host->name[len] = '0';
+				host->name[len + 1] = 0;
+			} else {
+				host->name[len - 1]++;
+			}
+			i = -1;	// restart loop
+		}
+	}
+}
 
 static void
 PrintSlist (void)
@@ -359,10 +413,6 @@ Slist_Poll (void *unused)
 	slistLocal = true;
 }
 
-
-int         hostCacheCount = 0;
-hostcache_t hostcache[HOSTCACHESIZE];
-
 qsocket_t *
 NET_Connect (const char *host)
 {

libs/net/nm/net_dgrm.c

@@ -880,8 +880,6 @@ static void
 _Datagram_SearchForHosts (qboolean xmit)
 {
 	int         ret;
-	int         n;
-	int         i;
 	netadr_t    readaddr;
 	netadr_t    myaddr;
 	int         control;
@@ -914,11 +912,6 @@ _Datagram_SearchForHosts (qboolean xmit)
 			continue;
 		}
 
-		// is the cache full?
-		if (hostCacheCount == HOSTCACHESIZE) {
-			continue;
-		}
-
 		MSG_BeginReading (net_message);
 		control = MSG_ReadLongBE (net_message);
 		if (control == -1) {
@@ -935,53 +928,25 @@ _Datagram_SearchForHosts (qboolean xmit)
 			continue;
 		}
 
-		dfunc.GetAddrFromName (MSG_ReadString (net_message), &readaddr);
+		const char *addrstr = MSG_ReadString (net_message);
-		// search the cache for this server
+		dfunc.GetAddrFromName (addrstr, &readaddr);
-		for (n = 0; n < hostCacheCount; n++) {
+
-			if (dfunc.AddrCompare (&readaddr, &hostcache[n].addr) == 0) {
+		const char *name = MSG_ReadString (net_message);
-				break;
+		const char *map = MSG_ReadString (net_message);
-			}
+		int         users = MSG_ReadByte (net_message);
+		int         maxusers = MSG_ReadByte (net_message);
+		int         protocol = MSG_ReadByte (net_message);
+		const char *cname = dfunc.AddrToString (&readaddr);
+
+		if (protocol != NET_PROTOCOL_VERSION) {
+			char       *new_name = alloca (strlen (name) + 2);
+			new_name[0] = '*';
+			strcpy (new_name + 1, name);
+			name = new_name;
 		}
 
-		// is it already there?
+		NET_AddCachedHost (name, map, cname, users, maxusers, net_driverlevel,
-		if (n < hostCacheCount) {
+						   net_landriverlevel, &readaddr);
-			continue;
-		}
-
-		// add it
-		hostCacheCount++;
-		strcpy (hostcache[n].name, MSG_ReadString (net_message));
-		strcpy (hostcache[n].map, MSG_ReadString (net_message));
-		hostcache[n].users = MSG_ReadByte (net_message);
-		hostcache[n].maxusers = MSG_ReadByte (net_message);
-		if (MSG_ReadByte (net_message) != NET_PROTOCOL_VERSION) {
-			strcpy (hostcache[n].cname, hostcache[n].name);
-			hostcache[n].cname[14] = 0;
-			strcpy (hostcache[n].name, "*");
-			strcat (hostcache[n].name, hostcache[n].cname);
-		}
-		memcpy (&hostcache[n].addr, &readaddr, sizeof (netadr_t));
-
-		hostcache[n].driver = net_driverlevel;
-		hostcache[n].ldriver = net_landriverlevel;
-		strcpy (hostcache[n].cname, dfunc.AddrToString (&readaddr));
-
-		// check for a name conflict
-		for (i = 0; i < hostCacheCount; i++) {
-			if (i == n) {
-				continue;
-			}
-			if (strcasecmp (hostcache[n].name, hostcache[i].name) == 0) {
-				i = strlen (hostcache[n].name);
-				if (i < 15 && hostcache[n].name[i - 1] > '8') {
-					hostcache[n].name[i] = '0';
-					hostcache[n].name[i + 1] = 0;
-				} else {
-					hostcache[n].name[i - 1]++;
-				}
-				i = -1;
-			}
-		}
 	}
 }
 
@@ -990,9 +955,6 @@ Datagram_SearchForHosts (qboolean xmit)
 {
 	for (net_landriverlevel = 0; net_landriverlevel < net_numlandrivers;
 		 net_landriverlevel++) {
-		if (hostCacheCount == HOSTCACHESIZE) {
-			break;
-		}
 		if (net_landrivers[net_landriverlevel].initialized) {
 			_Datagram_SearchForHosts (xmit);
 		}

libs/net/nm/net_loop.c

@@ -69,16 +69,16 @@ Loop_SearchForHosts (qboolean xmit)
 	if (!sv.active)
 		return;
 
-	hostCacheCount = 1;
+	const char *name = "local";
-	if (strcmp (hostname->string, "UNNAMED") == 0)
+	if (strcmp (hostname->string, "UNNAMED") != 0) {
-		strcpy (hostcache[0].name, "local");
+		name = hostname->string;
-	else
+	}
-		strcpy (hostcache[0].name, hostname->string);
+	const char *map = sv.name;
-	strcpy (hostcache[0].map, sv.name);
+	int         users = net_activeconnections;
-	hostcache[0].users = net_activeconnections;
+	int         maxusers = svs.maxclients;
-	hostcache[0].maxusers = svs.maxclients;
+	const char *cname = "local";
-	hostcache[0].driver = net_driverlevel;
+	NET_AddCachedHost (name, map, cname, users, maxusers, net_driverlevel,
-	strcpy (hostcache[0].cname, "local");
+					   0, 0);
 }