Add ability for device/network scan when rootless (#1700)

* Add ability for device/network scan when rootless

Signed-off-by: invario <67800603+invario@users.noreply.github.com>

* adjust err msg

---------

Signed-off-by: invario <67800603+invario@users.noreply.github.com>
Co-authored-by: Maxi Quoß <maxi@quoss.org>

backend/pb/handlers.go

@@ -2,14 +2,9 @@ package pb
 
 import (
 	"encoding/json"
-	"encoding/xml"
 	"fmt"
-	"net"
 	"net/http"
-	"os"
-	"os/exec"
 	"strconv"
-	"strings"
 	"time"
 
 	"github.com/pocketbase/dbx"
@@ -216,97 +211,6 @@ type Nmaprun struct {
 	} `xml:"host"`
 }
 
-func HandlerScan(e *core.RequestEvent) error {
-	// check if nmap installed
-	nmap, err := exec.LookPath("nmap")
-	if err != nil {
-		return apis.NewBadRequestError(err.Error(), nil)
-	}
-
-	// check if scan range is valid
-	allPrivateSettings, err := e.App.FindAllRecords("settings_private")
-	if err != nil {
-		return err
-	}
-	settingsPrivate := allPrivateSettings[0]
-	scanRange := settingsPrivate.GetString("scan_range")
-	_, ipNet, err := net.ParseCIDR(scanRange)
-	if err != nil {
-		return apis.NewBadRequestError(err.Error(), nil)
-	}
-
-	// run nmap
-	timeout := os.Getenv("UPSNAP_SCAN_TIMEOUT")
-	if timeout == "" {
-		timeout = "500ms"
-	}
-	cmd := exec.Command(nmap, "-sn", "-oX", "-", scanRange, "--host-timeout", timeout)
-	cmdOutput, err := cmd.Output()
-	if err != nil {
-		return err
-	}
-
-	// unmarshal xml
-	nmapOutput := Nmaprun{}
-	if err := xml.Unmarshal(cmdOutput, &nmapOutput); err != nil {
-		return err
-	}
-
-	type Device struct {
-		Name      string `json:"name"`
-		IP        string `json:"ip"`
-		MAC       string `json:"mac"`
-		MACVendor string `json:"mac_vendor"`
-	}
-
-	// extract info from struct into data
-	type Response struct {
-		Netmask string   `json:"netmask"`
-		Devices []Device `json:"devices"`
-	}
-	res := Response{}
-	var nm []string
-	for _, octet := range ipNet.Mask {
-		nm = append(nm, strconv.Itoa(int(octet)))
-	}
-	res.Netmask = strings.Join(nm, ".")
-
-	for _, host := range nmapOutput.Host {
-		dev := Device{}
-		for _, addr := range host.Address {
-			if addr.Addrtype == "ipv4" {
-				dev.IP = addr.Addr
-			} else if addr.Addrtype == "mac" {
-				dev.MAC = addr.Addr
-			}
-			if addr.Vendor != "" {
-				dev.MACVendor = addr.Vendor
-			} else {
-				dev.MACVendor = "Unknown"
-			}
-		}
-
-		if dev.IP == "" || dev.MAC == "" {
-			continue
-		}
-
-		names, err := net.LookupAddr(dev.IP)
-		if err != nil || len(names) == 0 {
-			dev.Name = dev.MACVendor
-		} else {
-			dev.Name = strings.TrimSuffix(names[0], ".")
-		}
-
-		if dev.Name == "" && dev.MACVendor == "" {
-			continue
-		}
-
-		res.Devices = append(res.Devices, dev)
-	}
-
-	return e.JSON(http.StatusOK, res)
-}
-
 func HandlerInitSuperuser(e *core.RequestEvent) error {
 	superusersCollection, err := e.App.FindCollectionByNameOrId(core.CollectionNameSuperusers)
 	if err != nil {

backend/pb/handlerscan_linux.go

@@ -0,0 +1,137 @@
+//go:build linux
+
+package pb
+
+import (
+	"encoding/xml"
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+
+	"github.com/pocketbase/pocketbase/apis"
+	"github.com/pocketbase/pocketbase/core"
+	"kernel.org/pub/linux/libs/security/libcap/cap"
+)
+
+func HandlerScan(e *core.RequestEvent) error {
+	// check if nmap installed
+	nmap, err := exec.LookPath("nmap")
+	if err != nil {
+		return apis.NewBadRequestError(err.Error(), nil)
+	}
+
+	// check if scan range is valid
+	allPrivateSettings, err := e.App.FindAllRecords("settings_private")
+	if err != nil {
+		return err
+	}
+	settingsPrivate := allPrivateSettings[0]
+	scanRange := settingsPrivate.GetString("scan_range")
+	_, ipNet, err := net.ParseCIDR(scanRange)
+	if err != nil {
+		return apis.NewBadRequestError(err.Error(), nil)
+	}
+
+	// run nmap
+	timeout := os.Getenv("UPSNAP_SCAN_TIMEOUT")
+	if timeout == "" {
+		timeout = "500ms"
+	}
+	orig := cap.GetProc()
+	defer orig.SetProc() // restore original caps on exit.
+
+	c, err := orig.Dup()
+	if err != nil {
+		return fmt.Errorf("Failed to dup existing capabilities: %v", err)
+	}
+
+	if on, _ := c.GetFlag(cap.Permitted, cap.NET_RAW); !on {
+		return fmt.Errorf("unable to get NET_RAW permissions")
+	}
+
+	if err := c.SetFlag(cap.Effective, true, cap.NET_RAW); err != nil {
+		return fmt.Errorf("unable to set NET_RAW capability effective")
+	}
+
+	if err := c.SetFlag(cap.Inheritable, true, cap.NET_RAW); err != nil {
+		return fmt.Errorf("unable to set NET_RAW capability inheritable")
+	}
+
+	if err := c.SetProc(); err != nil {
+		return fmt.Errorf("unable to raise NET_RAW capability")
+	}
+
+	if err := cap.SetAmbient(true, cap.NET_RAW); err != nil {
+		return fmt.Errorf("unable to set NET_RAW capability ambient")
+	}
+
+	cmd := exec.Command(nmap, "-sn", "-oX", "-", scanRange, "--host-timeout", timeout, "--privileged")
+	cmdOutput, err := cmd.Output()
+	if err != nil {
+		return err
+	}
+
+	// unmarshal xml
+	nmapOutput := Nmaprun{}
+	if err := xml.Unmarshal(cmdOutput, &nmapOutput); err != nil {
+		return err
+	}
+
+	type Device struct {
+		Name      string `json:"name"`
+		IP        string `json:"ip"`
+		MAC       string `json:"mac"`
+		MACVendor string `json:"mac_vendor"`
+	}
+
+	// extract info from struct into data
+	type Response struct {
+		Netmask string   `json:"netmask"`
+		Devices []Device `json:"devices"`
+	}
+	res := Response{}
+	var nm []string
+	for _, octet := range ipNet.Mask {
+		nm = append(nm, strconv.Itoa(int(octet)))
+	}
+	res.Netmask = strings.Join(nm, ".")
+
+	for _, host := range nmapOutput.Host {
+		dev := Device{}
+		for _, addr := range host.Address {
+			if addr.Addrtype == "ipv4" {
+				dev.IP = addr.Addr
+			} else if addr.Addrtype == "mac" {
+				dev.MAC = addr.Addr
+			}
+			if addr.Vendor != "" {
+				dev.MACVendor = addr.Vendor
+			} else {
+				dev.MACVendor = "Unknown"
+			}
+		}
+
+		if dev.IP == "" || dev.MAC == "" {
+			continue
+		}
+
+		names, err := net.LookupAddr(dev.IP)
+		if err != nil || len(names) == 0 {
+			dev.Name = dev.MACVendor
+		} else {
+			dev.Name = strings.TrimSuffix(names[0], ".")
+		}
+
+		if dev.Name == "" && dev.MACVendor == "" {
+			continue
+		}
+
+		res.Devices = append(res.Devices, dev)
+	}
+
+	return e.JSON(http.StatusOK, res)
+}

backend/pb/handlerscan_other.go

@@ -0,0 +1,107 @@
+//go:build !linux
+
+package pb
+
+import (
+	"encoding/xml"
+	"net"
+	"net/http"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+
+	"github.com/pocketbase/pocketbase/apis"
+	"github.com/pocketbase/pocketbase/core"
+)
+
+func HandlerScan(e *core.RequestEvent) error {
+	// check if nmap installed
+	nmap, err := exec.LookPath("nmap")
+	if err != nil {
+		return apis.NewBadRequestError(err.Error(), nil)
+	}
+
+	// check if scan range is valid
+	allPrivateSettings, err := e.App.FindAllRecords("settings_private")
+	if err != nil {
+		return err
+	}
+	settingsPrivate := allPrivateSettings[0]
+	scanRange := settingsPrivate.GetString("scan_range")
+	_, ipNet, err := net.ParseCIDR(scanRange)
+	if err != nil {
+		return apis.NewBadRequestError(err.Error(), nil)
+	}
+
+	// run nmap
+	timeout := os.Getenv("UPSNAP_SCAN_TIMEOUT")
+	if timeout == "" {
+		timeout = "500ms"
+	}
+	cmd := exec.Command(nmap, "-sn", "-oX", "-", scanRange, "--host-timeout", timeout, "--privileged")
+	cmdOutput, err := cmd.Output()
+	if err != nil {
+		return err
+	}
+
+	// unmarshal xml
+	nmapOutput := Nmaprun{}
+	if err := xml.Unmarshal(cmdOutput, &nmapOutput); err != nil {
+		return err
+	}
+
+	type Device struct {
+		Name      string `json:"name"`
+		IP        string `json:"ip"`
+		MAC       string `json:"mac"`
+		MACVendor string `json:"mac_vendor"`
+	}
+
+	// extract info from struct into data
+	type Response struct {
+		Netmask string   `json:"netmask"`
+		Devices []Device `json:"devices"`
+	}
+	res := Response{}
+	var nm []string
+	for _, octet := range ipNet.Mask {
+		nm = append(nm, strconv.Itoa(int(octet)))
+	}
+	res.Netmask = strings.Join(nm, ".")
+
+	for _, host := range nmapOutput.Host {
+		dev := Device{}
+		for _, addr := range host.Address {
+			if addr.Addrtype == "ipv4" {
+				dev.IP = addr.Addr
+			} else if addr.Addrtype == "mac" {
+				dev.MAC = addr.Addr
+			}
+			if addr.Vendor != "" {
+				dev.MACVendor = addr.Vendor
+			} else {
+				dev.MACVendor = "Unknown"
+			}
+		}
+
+		if dev.IP == "" || dev.MAC == "" {
+			continue
+		}
+
+		names, err := net.LookupAddr(dev.IP)
+		if err != nil || len(names) == 0 {
+			dev.Name = dev.MACVendor
+		} else {
+			dev.Name = strings.TrimSuffix(names[0], ".")
+		}
+
+		if dev.Name == "" && dev.MACVendor == "" {
+			continue
+		}
+
+		res.Devices = append(res.Devices, dev)
+	}
+
+	return e.JSON(http.StatusOK, res)
+}