Proper logging of all connections denied by firewall.

fw-daemon now also forces logging to syslog if launched from a terminal.

sgfw/log.go

@@ -4,6 +4,7 @@ import (
 	"os"
 	"syscall"
 	"unsafe"
+	"fmt"
 
 	"github.com/op/go-logging"
 )
@@ -43,14 +44,25 @@ func isTerminal(fd int) bool {
 	return err == 0
 }
 
-func setupLoggerBackend(lvl logging.Level) logging.LeveledBackend {
+func setupLoggerBackend(lvl logging.Level) (logging.LeveledBackend, logging.LeveledBackend) {
 	format := logFormat
+	sleveler := logging.LeveledBackend(nil)
 	if isTerminal(int(os.Stderr.Fd())) {
 		format = ttyFormat
+		fmt.Fprintf(os.Stderr, "Program was launched from a terminal; forcing output to syslog.\n")
+		sbackend, err := logging.NewSyslogBackend("sgfw")
+
+		if err != nil {
+			log.Error("Could not open syslog backend for logging: %v", err)
+		} else {
+			sformatter := logging.NewBackendFormatter(sbackend, logFormat)
+			sleveler = logging.AddModuleLevel(sformatter)
+			sleveler.SetLevel(lvl, "sgfw")
+		}
 	}
 	backend := logging.NewLogBackend(os.Stderr, "", 0)
 	formatter := logging.NewBackendFormatter(backend, format)
 	leveler := logging.AddModuleLevel(formatter)
 	leveler.SetLevel(lvl, "sgfw")
-	return leveler
+	return leveler, sleveler
 }

sgfw/policy.go

@@ -3,6 +3,7 @@ package sgfw
 import (
 	"fmt"
 	"strings"
+	"strconv"
 	"sync"
 
 //	"encoding/binary"
@@ -41,6 +42,7 @@ type pendingConnection interface {
 	hostname() string
 	getOptString() string
 	src() net.IP
+	srcPort() uint16
 	dst() net.IP
 	dstPort() uint16
 	accept()
@@ -105,6 +107,11 @@ func (pp *pendingPkt) dst() net.IP {
 //	pp.pkt.NetworkLayer().Layer
 }
 
+func (pp *pendingPkt) srcPort() uint16 {
+	srcp, _ := getPacketTCPPorts(pp.pkt)
+	return srcp
+}
+
 func (pp *pendingPkt) dstPort() uint16 {
 /*	dst := pp.pkt.Packet.TransportLayer().TransportFlow().Dst()
 
@@ -293,6 +300,9 @@ func (p *Policy) filterPending(rule *Rule) {
 			if rule.rtype == RULE_ACTION_ALLOW {
 				pc.accept()
 			} else {
+				srcs := pc.src().String() + ":" + strconv.Itoa(int(pc.srcPort()))
+				log.Warningf("DENIED outgoing connection attempt by %s from %s %s -> %s:%d (user prompt)",
+                                pc.procInfo().ExePath, "TCP", srcs, pc.dst(), pc.dstPort)
 				pc.drop()
 			}
 		} else {

sgfw/rules.go

@@ -127,6 +127,10 @@ log.Notice("+ MATCH SUCCEEDED")
 				srcStr,
 				dstStr, dstPort)
 			if r.rtype == RULE_ACTION_DENY {
+			log.Warningf("DENIED outgoing connection attempt by %s from %s %s -> %s:%d",
+				pinfo.ExePath, "TCP",
+				srcStr,
+				dstStr, dstPort)
 				return FILTER_DENY
 			} else if r.rtype == RULE_ACTION_ALLOW {
 				result = FILTER_ALLOW

sgfw/sgfw.go

@@ -173,8 +173,14 @@ func getSocksChainConfig(config *SocksJsonConfig) *socksChainConfig {
 
 func Main() {
 	readConfig()
-	logBackend := setupLoggerBackend(FirewallConfig.LoggingLevel)
+	logBackend, logBackend2 := setupLoggerBackend(FirewallConfig.LoggingLevel)
-	log.SetBackend(logBackend)
+
+	if logBackend2 == nil {
+		logging.SetBackend(logBackend)
+	} else {
+		logging.SetBackend(logBackend, logBackend2)
+	}
+
 	procsnitch.SetLogger(log)
 
 	if os.Geteuid() != 0 {

sgfw/socks_server_chain.go

@@ -7,6 +7,7 @@ import (
 	"sync"
 
 	"github.com/subgraph/go-procsnitch"
+	"strings"
 	"strconv"
 )
 
@@ -46,6 +47,7 @@ type pendingSocksConnection struct {
 	hname    string
 	srcIP   net.IP
 	destIP   net.IP
+	sourcePort uint16
 	destPort uint16
 	pinfo    *procsnitch.Info
 	verdict  chan int
@@ -70,6 +72,9 @@ func (sc *pendingSocksConnection) hostname() string {
 func (sc *pendingSocksConnection) dst() net.IP {
 	return sc.destIP
 }
+func (sc *pendingSocksConnection) srcPort() uint16 {
+	return sc.sourcePort
+}
 func (sc *pendingSocksConnection) dstPort() uint16 {
 	return sc.destPort
 }
@@ -204,11 +209,38 @@ func (c *socksChainSession) filterConnect() bool {
 	case FILTER_ALLOW:
 		return true
 	case FILTER_PROMPT:
+		caddr := c.clientConn.RemoteAddr().String()
+		caddrt := strings.Split(caddr, ":")
+		caddrIP := net.IP{0,0,0,0}
+		caddrPort := uint16(0)
+
+		if len(caddrt) != 2 {
+			log.Errorf("Error reading peer information from SOCKS client connection")
+		} else {
+			srcp, err := strconv.Atoi(caddrt[1])
+
+			if err != nil || srcp <= 0 || srcp > 65535 {
+				log.Errorf("Error getting port of SOCKS client connection")
+			} else {
+				caddrPort = uint16(srcp)
+				ip := net.ParseIP(caddrt[0])
+
+				if ip == nil {
+					log.Errorf("Error getting host IP of SOCKS5 client connection: %v", err)
+				} else {
+					caddrIP = ip
+				}
+
+			}
+
+		}
+
 		pending := &pendingSocksConnection{
 			pol:        policy,
 			hname:      hostname,
 			destIP:     ip,
-			srcIP:    net.IP{0,0,0,0},
+			srcIP:      caddrIP,
+			sourcePort: caddrPort,
 			destPort:   port,
 			pinfo:      pinfo,
 			verdict:    make(chan int),