Revamp process attribution of network connections

network/proc/tables.go

@@ -0,0 +1,218 @@
+// +build linux
+
+package proc
+
+import (
+	"bufio"
+	"encoding/hex"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"unicode"
+
+	"github.com/safing/portmaster/network/socket"
+
+	"github.com/safing/portbase/log"
+)
+
+/*
+
+1. find socket inode
+  - by incoming (listenting sockets) or outgoing (local port + external IP + port) - also local IP?
+  - /proc/net/{tcp|udp}[6]
+
+2. get list of processes of uid
+
+3. find socket inode in process fds
+	- if not found, refresh map of uid->pids
+	- if not found, check ALL pids: maybe euid != uid
+
+4. gather process info
+
+Cache every step!
+
+*/
+
+// Network Related Constants
+const (
+	TCP4 uint8 = iota
+	UDP4
+	TCP6
+	UDP6
+	ICMP4
+	ICMP6
+
+	TCP4Data  = "/proc/net/tcp"
+	UDP4Data  = "/proc/net/udp"
+	TCP6Data  = "/proc/net/tcp6"
+	UDP6Data  = "/proc/net/udp6"
+	ICMP4Data = "/proc/net/icmp"
+	ICMP6Data = "/proc/net/icmp6"
+
+	UnfetchedProcessID = -2
+
+	tcpListenStateHex = "0A"
+)
+
+// GetTCP4Table returns the system table for IPv4 TCP activity.
+func GetTCP4Table() (connections []*socket.ConnectionInfo, listeners []*socket.BindInfo, err error) {
+	return getTableFromSource(TCP4, TCP4Data, convertIPv4)
+}
+
+// GetTCP6Table returns the system table for IPv6 TCP activity.
+func GetTCP6Table() (connections []*socket.ConnectionInfo, listeners []*socket.BindInfo, err error) {
+	return getTableFromSource(TCP6, TCP6Data, convertIPv6)
+}
+
+// GetUDP4Table returns the system table for IPv4 UDP activity.
+func GetUDP4Table() (binds []*socket.BindInfo, err error) {
+	_, binds, err = getTableFromSource(UDP4, UDP4Data, convertIPv4)
+	return
+}
+
+// GetUDP6Table returns the system table for IPv6 UDP activity.
+func GetUDP6Table() (binds []*socket.BindInfo, err error) {
+	_, binds, err = getTableFromSource(UDP6, UDP6Data, convertIPv6)
+	return
+}
+
+func getTableFromSource(stack uint8, procFile string, ipConverter func(string) net.IP) (connections []*socket.ConnectionInfo, binds []*socket.BindInfo, err error) {
+
+	// open file
+	socketData, err := os.Open(procFile)
+	if err != nil {
+		return nil, nil, err
+	}
+	defer socketData.Close()
+
+	// file scanner
+	scanner := bufio.NewScanner(socketData)
+	scanner.Split(bufio.ScanLines)
+
+	// parse
+	scanner.Scan() // skip first line
+	for scanner.Scan() {
+		line := strings.FieldsFunc(scanner.Text(), procDelimiter)
+		if len(line) < 14 {
+			// log.Tracef("process: too short: %s", line)
+			continue
+		}
+
+		localIP := ipConverter(line[1])
+		if localIP == nil {
+			continue
+		}
+
+		localPort, err := strconv.ParseUint(line[2], 16, 16)
+		if err != nil {
+			log.Warningf("process: could not parse port: %s", err)
+			continue
+		}
+
+		uid, err := strconv.ParseInt(line[11], 10, 32)
+		// log.Tracef("uid: %s", line[11])
+		if err != nil {
+			log.Warningf("process: could not parse uid %s: %s", line[11], err)
+			continue
+		}
+
+		inode, err := strconv.ParseInt(line[13], 10, 32)
+		// log.Tracef("inode: %s", line[13])
+		if err != nil {
+			log.Warningf("process: could not parse inode %s: %s", line[13], err)
+			continue
+		}
+
+		switch stack {
+		case UDP4, UDP6:
+
+			binds = append(binds, &socket.BindInfo{
+				Local: socket.Address{
+					IP:   localIP,
+					Port: uint16(localPort),
+				},
+				PID:   UnfetchedProcessID,
+				UID:   int(uid),
+				Inode: int(inode),
+			})
+
+		case TCP4, TCP6:
+
+			if line[5] == tcpListenStateHex {
+				// listener
+
+				binds = append(binds, &socket.BindInfo{
+					Local: socket.Address{
+						IP:   localIP,
+						Port: uint16(localPort),
+					},
+					PID:   UnfetchedProcessID,
+					UID:   int(uid),
+					Inode: int(inode),
+				})
+			} else {
+				// connection
+
+				remoteIP := ipConverter(line[3])
+				if remoteIP == nil {
+					continue
+				}
+
+				remotePort, err := strconv.ParseUint(line[4], 16, 16)
+				if err != nil {
+					log.Warningf("process: could not parse port: %s", err)
+					continue
+				}
+
+				connections = append(connections, &socket.ConnectionInfo{
+					Local: socket.Address{
+						IP:   localIP,
+						Port: uint16(localPort),
+					},
+					Remote: socket.Address{
+						IP:   remoteIP,
+						Port: uint16(remotePort),
+					},
+					PID:   UnfetchedProcessID,
+					UID:   int(uid),
+					Inode: int(inode),
+				})
+			}
+		}
+	}
+
+	return connections, binds, nil
+}
+
+func procDelimiter(c rune) bool {
+	return unicode.IsSpace(c) || c == ':'
+}
+
+func convertIPv4(data string) net.IP {
+	decoded, err := hex.DecodeString(data)
+	if err != nil {
+		log.Warningf("process: could not parse IPv4 %s: %s", data, err)
+		return nil
+	}
+	if len(decoded) != 4 {
+		log.Warningf("process: decoded IPv4 %s has wrong length", decoded)
+		return nil
+	}
+	ip := net.IPv4(decoded[3], decoded[2], decoded[1], decoded[0])
+	return ip
+}
+
+func convertIPv6(data string) net.IP {
+	decoded, err := hex.DecodeString(data)
+	if err != nil {
+		log.Warningf("process: could not parse IPv6 %s: %s", data, err)
+		return nil
+	}
+	if len(decoded) != 16 {
+		log.Warningf("process: decoded IPv6 %s has wrong length", decoded)
+		return nil
+	}
+	ip := net.IP(decoded)
+	return ip
+}