Merge pull request #72 from safing/fix/network-state-pid-searching

Retry finding a socket's PID on linux

network/proc/findpid.go

@@ -16,21 +16,48 @@ import (
 )
 
 var (
+	// pidsByUserLock is also used for locking the socketInfo.PID on all socket.*Info structs.
 	pidsByUserLock sync.Mutex
 	pidsByUser     = make(map[int][]int)
 )
 
-// FindPID returns the pid of the given uid and socket inode.
+// FindConnectionPID returns the pid of the given socket info.
-func FindPID(uid, inode int) (pid int) { //nolint:gocognit // TODO
+func FindConnectionPID(socketInfo *socket.ConnectionInfo) (pid int) {
 	pidsByUserLock.Lock()
 	defer pidsByUserLock.Unlock()
 
+	if socketInfo.PID != socket.UnidentifiedProcessID {
+		return socket.UnidentifiedProcessID
+	}
+
+	pid = findPID(socketInfo.UID, socketInfo.Inode)
+	socketInfo.PID = pid
+	return pid
+}
+
+// FindBindPID returns the pid of the given socket info.
+func FindBindPID(socketInfo *socket.BindInfo) (pid int) {
+	pidsByUserLock.Lock()
+	defer pidsByUserLock.Unlock()
+
+	if socketInfo.PID != socket.UnidentifiedProcessID {
+		return socket.UnidentifiedProcessID
+	}
+
+	pid = findPID(socketInfo.UID, socketInfo.Inode)
+	socketInfo.PID = pid
+	return pid
+}
+
+// findPID returns the pid of the given uid and socket inode.
+func findPID(uid, inode int) (pid int) { //nolint:gocognit // TODO
+
 	pidsUpdated := false
 
 	// get pids of user, update if missing
 	pids, ok := pidsByUser[uid]
 	if !ok {
-		// log.Trace("process: no processes of user, updating table")
+		// log.Trace("proc: no processes of user, updating table")
 		updatePids()
 		pidsUpdated = true
 		pids, ok = pidsByUser[uid]
@@ -46,7 +73,7 @@ func FindPID(uid, inode int) (pid int) { //nolint:gocognit // TODO
 		}
 		// if we fail on the first run and have not updated, update and check the ones we haven't tried so far.
 		if !pidsUpdated {
-			// log.Trace("process: socket not found in any process of user, updating table")
+			// log.Trace("proc: socket not found in any process of user, updating table")
 			// update
 			updatePids()
 			// sort for faster search
@@ -67,7 +94,7 @@ func FindPID(uid, inode int) (pid int) { //nolint:gocognit // TODO
 	}
 
 	// check all other pids
-	// log.Trace("process: socket not found in any process of user, checking all pids")
+	// log.Trace("proc: socket not found in any process of user, checking all pids")
 	// TODO: find best order for pidsByUser for best performance
 	for possibleUID, pids := range pidsByUser {
 		if possibleUID != uid {
@@ -93,7 +120,7 @@ func findSocketFromPid(pid, inode int) bool {
 		link, err := os.Readlink(fmt.Sprintf("/proc/%d/fd/%s", pid, entry))
 		if err != nil {
 			if !os.IsNotExist(err) {
-				log.Warningf("process: failed to read link /proc/%d/fd/%s: %s", pid, entry, err)
+				log.Warningf("proc: failed to read link /proc/%d/fd/%s: %s", pid, entry, err)
 			}
 			continue
 		}
@@ -122,12 +149,12 @@ entryLoop:
 
 		statData, err := os.Stat(fmt.Sprintf("/proc/%d", pid))
 		if err != nil {
-			log.Warningf("process: could not stat /proc/%d: %s", pid, err)
+			log.Warningf("proc: could not stat /proc/%d: %s", pid, err)
 			continue entryLoop
 		}
 		sys, ok := statData.Sys().(*syscall.Stat_t)
 		if !ok {
-			log.Warningf("process: unable to parse /proc/%d: wrong type", pid)
+			log.Warningf("proc: unable to parse /proc/%d: wrong type", pid)
 			continue entryLoop
 		}
 
@@ -152,14 +179,14 @@ func readDirNames(dir string) (names []string) {
 	file, err := os.Open(dir)
 	if err != nil {
 		if !os.IsNotExist(err) {
-			log.Warningf("process: could not open directory %s: %s", dir, err)
+			log.Warningf("proc: could not open directory %s: %s", dir, err)
 		}
 		return
 	}
 	defer file.Close()
 	names, err = file.Readdirnames(0)
 	if err != nil {
-		log.Warningf("process: could not get entries from directory %s: %s", dir, err)
+		log.Warningf("proc: could not get entries from directory %s: %s", dir, err)
 		return []string{}
 	}
 	return

network/proc/tables.go

@@ -49,8 +49,6 @@ const (
 	udp4ProcFile = "/proc/net/udp"
 	udp6ProcFile = "/proc/net/udp6"
 
-	UnfetchedProcessID = -2
-
 	tcpListenStateHex = "0A"
 )
 
@@ -114,7 +112,7 @@ func getTableFromSource(stack uint8, procFile string) (connections []*socket.Con
 	for scanner.Scan() {
 		fields := strings.FieldsFunc(scanner.Text(), procDelimiter)
 		if len(fields) < 14 {
-			// log.Tracef("process: too short: %s", fields)
+			// log.Tracef("proc: too short: %s", fields)
 			continue
 		}
 
@@ -125,21 +123,21 @@ func getTableFromSource(stack uint8, procFile string) (connections []*socket.Con
 
 		localPort, err := strconv.ParseUint(fields[fieldIndexLocalPort], 16, 16)
 		if err != nil {
-			log.Warningf("process: could not parse port: %s", err)
+			log.Warningf("proc: could not parse port: %s", err)
 			continue
 		}
 
 		uid, err := strconv.ParseInt(fields[fieldIndexUID], 10, 32)
 		// log.Tracef("uid: %s", fields[fieldIndexUID])
 		if err != nil {
-			log.Warningf("process: could not parse uid %s: %s", fields[11], err)
+			log.Warningf("proc: could not parse uid %s: %s", fields[11], err)
 			continue
 		}
 
 		inode, err := strconv.ParseInt(fields[fieldIndexInode], 10, 32)
 		// log.Tracef("inode: %s", fields[fieldIndexInode])
 		if err != nil {
-			log.Warningf("process: could not parse inode %s: %s", fields[13], err)
+			log.Warningf("proc: could not parse inode %s: %s", fields[13], err)
 			continue
 		}
 
@@ -151,7 +149,7 @@ func getTableFromSource(stack uint8, procFile string) (connections []*socket.Con
 					IP:   localIP,
 					Port: uint16(localPort),
 				},
-				PID:   UnfetchedProcessID,
+				PID:   socket.UnidentifiedProcessID,
 				UID:   int(uid),
 				Inode: int(inode),
 			})
@@ -166,7 +164,7 @@ func getTableFromSource(stack uint8, procFile string) (connections []*socket.Con
 						IP:   localIP,
 						Port: uint16(localPort),
 					},
-					PID:   UnfetchedProcessID,
+					PID:   socket.UnidentifiedProcessID,
 					UID:   int(uid),
 					Inode: int(inode),
 				})
@@ -180,7 +178,7 @@ func getTableFromSource(stack uint8, procFile string) (connections []*socket.Con
 
 				remotePort, err := strconv.ParseUint(fields[fieldIndexRemotePort], 16, 16)
 				if err != nil {
-					log.Warningf("process: could not parse port: %s", err)
+					log.Warningf("proc: could not parse port: %s", err)
 					continue
 				}
 
@@ -193,7 +191,7 @@ func getTableFromSource(stack uint8, procFile string) (connections []*socket.Con
 						IP:   remoteIP,
 						Port: uint16(remotePort),
 					},
-					PID:   UnfetchedProcessID,
+					PID:   socket.UnidentifiedProcessID,
 					UID:   int(uid),
 					Inode: int(inode),
 				})
@@ -211,11 +209,11 @@ func procDelimiter(c rune) bool {
 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)
+		log.Warningf("proc: could not parse IPv4 %s: %s", data, err)
 		return nil
 	}
 	if len(decoded) != 4 {
-		log.Warningf("process: decoded IPv4 %s has wrong length", decoded)
+		log.Warningf("proc: decoded IPv4 %s has wrong length", decoded)
 		return nil
 	}
 	ip := net.IPv4(decoded[3], decoded[2], decoded[1], decoded[0])
@@ -225,11 +223,11 @@ func convertIPv4(data string) net.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)
+		log.Warningf("proc: could not parse IPv6 %s: %s", data, err)
 		return nil
 	}
 	if len(decoded) != 16 {
-		log.Warningf("process: decoded IPv6 %s has wrong length", decoded)
+		log.Warningf("proc: decoded IPv6 %s has wrong length", decoded)
 		return nil
 	}
 	ip := net.IP(decoded)

network/proc/tables_test.go

@@ -14,12 +14,12 @@ func TestSockets(t *testing.T) {
 	}
 	fmt.Println("\nTCP 4 connections:")
 	for _, connection := range connections {
-		pid := FindPID(connection.UID, connection.Inode)
+		pid := FindConnectionPID(connection)
 		fmt.Printf("%d: %+v\n", pid, connection)
 	}
 	fmt.Println("\nTCP 4 listeners:")
 	for _, listener := range listeners {
-		pid := FindPID(listener.UID, listener.Inode)
+		pid := FindBindPID(listener)
 		fmt.Printf("%d: %+v\n", pid, listener)
 	}
 
@@ -29,12 +29,12 @@ func TestSockets(t *testing.T) {
 	}
 	fmt.Println("\nTCP 6 connections:")
 	for _, connection := range connections {
-		pid := FindPID(connection.UID, connection.Inode)
+		pid := FindConnectionPID(connection)
 		fmt.Printf("%d: %+v\n", pid, connection)
 	}
 	fmt.Println("\nTCP 6 listeners:")
 	for _, listener := range listeners {
-		pid := FindPID(listener.UID, listener.Inode)
+		pid := FindBindPID(listener)
 		fmt.Printf("%d: %+v\n", pid, listener)
 	}
 
@@ -44,7 +44,7 @@ func TestSockets(t *testing.T) {
 	}
 	fmt.Println("\nUDP 4 binds:")
 	for _, bind := range binds {
-		pid := FindPID(bind.UID, bind.Inode)
+		pid := FindBindPID(bind)
 		fmt.Printf("%d: %+v\n", pid, bind)
 	}
 
@@ -54,7 +54,7 @@ func TestSockets(t *testing.T) {
 	}
 	fmt.Println("\nUDP 6 binds:")
 	for _, bind := range binds {
-		pid := FindPID(bind.UID, bind.Inode)
+		pid := FindBindPID(bind)
 		fmt.Printf("%d: %+v\n", pid, bind)
 	}
 }

network/state/system_linux.go

@@ -1,6 +1,8 @@
 package state
 
 import (
+	"time"
+
 	"github.com/safing/portmaster/network/proc"
 	"github.com/safing/portmaster/network/socket"
 )
@@ -13,15 +15,41 @@ var (
 )
 
 func checkConnectionPID(socketInfo *socket.ConnectionInfo, connInbound bool) (pid int, inbound bool, err error) {
-	if socketInfo.PID == proc.UnfetchedProcessID {
+	for i := 0; i <= lookupRetries; i++ {
-		socketInfo.PID = proc.FindPID(socketInfo.UID, socketInfo.Inode)
+		// look for PID
+		pid = proc.FindConnectionPID(socketInfo)
+		if pid != socket.UnidentifiedProcessID {
+			// if we found a PID, return
+			break
+		}
+
+		// every time, except for the last iteration
+		if i < lookupRetries {
+			// we found no PID, we could have been too fast, give the kernel some time to think
+			// back off timer: with 3ms baseWaitTime: 3, 6, 9, 12, 15, 18, 21ms - 84ms in total
+			time.Sleep(time.Duration(i+1) * baseWaitTime)
+		}
 	}
-	return socketInfo.PID, connInbound, nil
+
+	return pid, connInbound, nil
 }
 
 func checkBindPID(socketInfo *socket.BindInfo, connInbound bool) (pid int, inbound bool, err error) {
-	if socketInfo.PID == proc.UnfetchedProcessID {
+	for i := 0; i <= lookupRetries; i++ {
-		socketInfo.PID = proc.FindPID(socketInfo.UID, socketInfo.Inode)
+		// look for PID
+		pid = proc.FindBindPID(socketInfo)
+		if pid != socket.UnidentifiedProcessID {
+			// if we found a PID, return
+			break
+		}
+
+		// every time, except for the last iteration
+		if i < lookupRetries {
+			// we found no PID, we could have been too fast, give the kernel some time to think
+			// back off timer: with 3ms baseWaitTime: 3, 6, 9, 12, 15, 18, 21ms - 84ms in total
+			time.Sleep(time.Duration(i+1) * baseWaitTime)
+		}
 	}
-	return socketInfo.PID, connInbound, nil
+
+	return pid, connInbound, nil
 }