Fixed possible undefined behaviour when UDP RX buffer fills

make-linux.mk

@@ -21,6 +21,7 @@ endif
 INCLUDES?=
 DEFS?=
 LDLIBS?=
+CFLAGS=
 
 include objects.mk
 
@@ -110,7 +111,7 @@ one: $(OBJS) $(ZT1)/service/OneService.o $(ZT1)/one.o $(ZT1)/osdep/LinuxEthernet
 # Build only the intercept library
 linux_intercept:
 	# Use gcc not clang to build standalone intercept library since gcc is typically used for libc and we want to ensure maximal ABI compatibility
-	cd src ; gcc $(DEFS) -O2 -Wall -std=c99 -fPIC -DVERBOSE -D_GNU_SOURCE -DSDK_INTERCEPT -I. -I../$(ZT1)/node -nostdlib -shared -o ../$(INTERCEPT) SDK_Sockets.c SDK_Intercept.c SDK_Debug.c SDK_RPC.c -ldl
+	cd src ; gcc $(CFLAGS) $(DEFS) -O2 -Wall -std=c99 -fPIC -DVERBOSE -D_GNU_SOURCE -DSDK_INTERCEPT -I. -I../$(ZT1)/node -nostdlib -shared -o ../$(INTERCEPT) SDK_Sockets.c SDK_Intercept.c SDK_Debug.c SDK_RPC.c -ldl
 
 # Build only the SDK service
 linux_sdk_service: lwip $(OBJS)

make-mac.mk

@@ -18,6 +18,7 @@ INCLUDES=
 DEFS=
 LIBS=
 ARCH_FLAGS=-arch x86_64
+CFLAGS=
 
 include objects.mk
 
@@ -136,7 +137,7 @@ osx_shared_lib: remove_only_intermediates $(OBJS)
 
 osx_intercept:
 	# Use gcc not clang to build standalone intercept library since gcc is typically used for libc and we want to ensure maximal ABI compatibility
-	cd src ; gcc $(DEFS) -O2 -Wall -std=c99 -fPIC -fno-common -dynamiclib -flat_namespace -DVERBOSE -D_GNU_SOURCE -DNETCON_INTERCEPT -I. -I../zerotierone/node -nostdlib -shared -o ../$(INTERCEPT) SDK_Sockets.c SDK_Intercept.c SDK_Debug.c SDK_RPC.c -ldl
+	cd src ; gcc $(CFLAGS) $(DEFS) -O2 -Wall -std=c99 -fPIC -fno-common -dynamiclib -flat_namespace -DVERBOSE -D_GNU_SOURCE -DNETCON_INTERCEPT -I. -I../zerotierone/node -nostdlib -shared -o ../$(INTERCEPT) SDK_Sockets.c SDK_Intercept.c SDK_Debug.c SDK_RPC.c -ldl
 	#mv src/$(INTERCEPT_NAME) $(INTERCEPT)
 
 # Build only the SDK service
@@ -151,7 +152,7 @@ osx_service_and_intercept: remove_only_intermediates osx_intercept osx_sdk_servi
 
 
 # -------- ANDROID ---------
-# Build all Android targets 
+# Build all Android targets
 # Chip architectures can be specified in integrations/android/android_jni_lib/java/jni/Application.mk
 android: android_jni_lib
 

src/SDK_EthernetTap.cpp

@@ -119,16 +119,16 @@ NetconEthernetTap::NetconEthernetTap(
 	const char *friendlyName,
 	void (*handler)(void *,uint64_t,const MAC &,const MAC &,unsigned int,unsigned int,const void *,unsigned int),
 	void *arg) :
-  _nwid(nwid),
-	_handler(handler),
-	_arg(arg),
-  _phy(this,false,true),
-  _unixListenSocket((PhySocket *)0),
-	_mac(mac),
-	_homePath(homePath),
-	_mtu(mtu),
-	_enabled(true),
-	_run(true)
+		_homePath(homePath),
+		_mac(mac),
+		_mtu(mtu),
+		_nwid(nwid),
+		_handler(handler),
+		_arg(arg),
+		_phy(this,false,true),
+		_unixListenSocket((PhySocket *)0),
+		_enabled(true),
+		_run(true)
 {
 	sockstate = -1;
     char sockPath[4096],lwipPath[4096];
@@ -763,11 +763,12 @@ void NetconEthernetTap::nc_udp_recved(void * arg, struct udp_pcb * upcb, struct
     // Cycle through pbufs and write them to the RX buffer
     // The RX "buffer" will be emptied via phyOnUnixWritable()
 	if(p) {
-		// Intra-API "packetization" structure: [addr_len|addr|payload_len|payload]
+		// Intra-API "packetization" scheme: [addr_len|addr|payload_len|payload]
 		if(l->conn->rxsz == DEFAULT_UDP_RX_BUF_SZ) { // if UDP buffer full
 			dwr(MSG_DEBUG, "nc_udp_recved(): UDP RX buffer full. Discarding oldest payload segment\n");
 			memmove(l->conn->rxbuf, l->conn->rxbuf + ZT_MAX_MTU, DEFAULT_UDP_RX_BUF_SZ - ZT_MAX_MTU);
-			sz_pos = l->conn->rxbuf + (DEFAULT_UDP_RX_BUF_SZ - ZT_MAX_MTU) + sizeof(struct sockaddr_storage);
+			addr_pos = l->conn->rxbuf + (DEFAULT_UDP_RX_BUF_SZ - ZT_MAX_MTU); // TODO:
+			sz_pos = addr_pos + sizeof(struct sockaddr_storage);
 			l->conn->rxsz -= ZT_MAX_MTU;
 		}
 		else {

src/SDK_Signatures.h

@@ -36,7 +36,7 @@
 #define SENDMSG_SIG int socket, const struct msghdr *message, int flags
 #define SENDTO_SIG int sockfd, const void *buf, size_t len, int flags, const struct sockaddr *addr, socklen_t addr_len
 #define RECV_SIG int socket, void *buffer, size_t length, int flags
-#define RECVFROM_SIG int socket, void * buffer, size_t length, int flags, struct sockaddr_in * address, socklen_t * address_len
+#define RECVFROM_SIG int socket, void * buffer, size_t length, int flags, struct sockaddr * address, socklen_t * address_len
 #define RECVMSG_SIG int socket, struct msghdr *message,int flags
 
 #define SEND_SIG int socket, const void *buffer, size_t length, int flags

src/SDK_Sockets.c

@@ -260,7 +260,7 @@ int (*realclose)(CLOSE_SIG);
         jbyte *body = (*env)->GetByteArrayElements(env, buf, 0);
         unsigned char buffer[ZT_MAX_MTU];
         int payload_offset = sizeof(int) + sizeof(struct sockaddr_storage);
-        int rxbytes = zts_recvfrom(fd, &buffer, len, flags, &addr, sizeof(struct sockaddr));
+        int rxbytes = zts_recvfrom(fd, &buffer, len, flags, &addr, sizeof(struct sockaddr_storage));
         if(rxbytes > 0)
             memcpy(body, (jbyte*)buffer + payload_offset, rxbytes);
         (*env)->ReleaseByteArrayElements(env, buf, body, 0);