validator: implement PXE template

tftp/pxelinux.cfg/default

@@ -1,29 +1,10 @@
-DEFAULT vesamenu.c32
+DEFAULT login
-
-MENU RESOLUTION 1024 768
-NOESCAPE 1
-ALLOWOPTIONS 0
-
-#MENU BACKGROUND	splash.png
-MENU BACKGROUND		#00000000 * *
-MENU COLOR TITLE	* #FF22BBCC *
-#MENU COLOR BORDER	* #FFFFFFFF #00000000 none
-MENU COLOR SEL		* #FFFFFFFF #FF22BBCC *
-MENU COLOR HOTSEL	1;7;37;40 #ffffffff #76a1d0ff *
-#MENU COLOR TABMSG	* #ffffffff #00000000 *
-#MENU COLOR HELP	37;40 #ffdddd00 #00000000 *
-MENU TABMSG Press ENTER to boot or TAB to edit a menu entry
-
-PROMPT 0
-TIMEOUT 1
-
-MENU TITLE Welcome to the EPITA ADvanced LINux administration course!
 
 LABEL login
   MENU LABEL ^Login
-  KERNEL adlin/login-kernel
+  KERNEL bzImage
-  INITRD adlin/login-initrd.img
+  INITRD initramfs-login.img
-  APPEND console=tty0
+  APPEND console=tty0 quiet
   TEXT help
           You are currently not identified.
           Please select this menu entry in order to access the tutorial.

tftp/pxelinux.cfg/tpl

@@ -0,0 +1,48 @@
+default vesamenu.c32
+
+MENU RESOLUTION 1024 768
+
+#menu background splash.png
+menu background		#00000000 * *
+menu color title	* #FF22BBCC *
+#menu color border	* #FFFFFFFF #00000000 none
+menu color sel		* #FFFFFFFF #FF22BBCC *
+menu color hotsel	1;7;37;40 #ffffffff #76a1d0ff *
+#menu color tabmsg	* #ffffffff #00000000 *
+#menu color help		37;40 #ffdddd00 #00000000 *
+menu tabmsg Press ENTER to boot or TAB to edit a menu entry
+
+prompt 0
+timeout 0
+
+menu title Welcome {{ .username }} to the EPITA ADvanced LINux administration course!
+
+LABEL challenge
+  MENU LABEL ^Enter Challenge
+  KERNEL bzImage
+  INITRD initramfs-challenge.img
+  APPEND console=tty0 quiet
+  text help
+          You are currently identified as {{ .username }}.
+          Please select this menu entry in order to access the tutorial.
+  endtext
+
+MENU SEPARATOR
+
+LABEL logout
+  MENU LABEL Not {{ .username }}? ^logout
+  KERNEL bzImage
+  INITRD initramfs-login.img
+  APPEND console=tty0 quiet
+  text help
+          You are currently identified as {{ .username }}.
+          If this is not you, you should logout right now, using this menu entry!
+
+	  You'll next be able to login as another user.
+  endtext
+
+MENU SEPARATOR
+
+LABEL poweroff
+  MENU LABEL ^Shutdown
+  KERNEL poweroff.c32

validator/login.go

@@ -54,9 +54,48 @@ func (l loginChecker) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if !canContinue {
+		log.Println("Login not found:", lu.Username, "at", r.RemoteAddr)
 		http.Error(w, "Login not found in whitelist.", http.StatusUnauthorized)
 		return
 	}
 
+	if err := l.lateLoginAction(lu.Username, r.RemoteAddr); err != nil {
+		log.Println("Error on late login action:", err)
+		http.Error(w, "Internal server error. Please retry in a few minutes", http.StatusInternalServerError)
+		return
+	}
+
+	log.Println("Successful login of", lu.Username, "at", r.RemoteAddr)
 	http.Error(w, "Success", http.StatusOK)
 }
+
+func (l loginChecker) lateLoginAction(username, remoteAddr string) error {
+	// Find corresponding MAC
+	var fname string
+	spl := strings.SplitN(remoteAddr, ":", 2)
+	if ip := net.ParseIP(spl[0]); ip == nil {
+		return errors.New("Unable to parse given IPv4: " + spl[0])
+	} else if arptable, err := ARPAnalyze(); err != nil {
+		return err
+	} else if arpent := ARPContainsIP(arptable, ip); arpent == nil {
+		return errors.New("Unable to find MAC in ARP table")
+	} else {
+		fname = fmt.Sprintf("%02x-%02x-%02x-%02x-%02x-%02x-%02x", arpent.HWType, arpent.HWAddress[0], arpent.HWAddress[1], arpent.HWAddress[2], arpent.HWAddress[3], arpent.HWAddress[4], arpent.HWAddress[5])
+	}
+
+	if tpl, err := ioutil.ReadFile(path.Join(tftpDir, "pxelinux.cfg", "tpl")); err != nil {
+		log.Println("Unable to open tpl: ", err)
+	} else if file, err := os.OpenFile(path.Join(tftpDir, "pxelinux.cfg", fname), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(0644)); err != nil {
+		log.Println("Unable to open destination file: ", err)
+	} else {
+		defer file.Close()
+
+		if configTmpl, err := template.New("pxelinux.cfg").Parse(string(tpl)); err != nil {
+			log.Println("Cannot create template: ", err)
+		} else if err := configTmpl.Execute(file, map[string]string{"username": username, "remoteAddr": remoteAddr, "fname": fname}); err != nil {
+			log.Println("An error occurs during template execution: ", err)
+		}
+	}
+
+	return nil
+}

validator/main.go

@@ -7,22 +7,22 @@ import (
 	"path/filepath"
 )
 
+var tftpDir string
+
 func main() {
-	var staticDir string
 	var studentsFile string
 
 	var bind = flag.String("bind", ":8081", "Bind port/socket")
 	flag.StringVar(&studentsFile, "students", "./students.csv", "Path to a CSV file containing students list")
-	flag.StringVar(&staticDir, "static", "./static/", "Directory containing static files")
 	flag.StringVar(&ARPTable, "arp", ARPTable, "Path to ARP table")
-	//var tftpdLogs = flag.String("tftpd", "/var/logs/tftpd.log", "Path to TFTPd logs")
+	flag.StringVar(&tftpDir, "tftpdir", "/var/tftp/", "Path to TFTPd directory")
 	flag.Parse()
 
 	var err error
 
 	// Sanitize options
 	log.Println("Checking paths...")
-	if staticDir, err = filepath.Abs(staticDir); err != nil {
+	if tftpDir, err = filepath.Abs(tftpDir); err != nil {
 		log.Fatal(err)
 	}
 

validator/pxetpl.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net"
+	"os"
+	"path"
+	"text/template"
+)
+
+const pxeUserTplPath = "pxelinux.cfg/tpl"
+const pxeUserPath = "pxelinux.cfg"
+
+func RegisterUserMAC(ip net.IP, username string) error {
+	if tab, err := ARPAnalyze(); err != nil {
+		return err
+	} else if ent := ARPContainsIP(tab, ip); ent == nil {
+		return errors.New(fmt.Sprintf("Unable to find MAC address for given IP (%s)", ip))
+	} else {
+		return registerUser(fmt.Sprintf("%02X-%02X-%02X-%02X-%02X-%02X-%02X", ent.HWType, ent.HWAddress[0], ent.HWAddress[1], ent.HWAddress[2], ent.HWAddress[3], ent.HWAddress[4], ent.HWAddress[5]), username)
+	}
+}
+
+func RegisterUserIP(ip net.IP, username string) error {
+	return registerUser(fmt.Sprintf("%02X%02X%02X%02X", ip.To4()[0], ip.To4()[1], ip.To4()[2], ip.To4()[3]), username)
+}
+
+func registerUser(filename string, username string) error {
+	if pxeTplCnt, err := ioutil.ReadFile(path.Join(tftpDir, pxeUserTplPath)); err != nil {
+		return err
+	} else if userfd, err := os.OpenFile(path.Join(tftpDir, pxeUserPath, filename), os.O_RDWR|os.O_CREATE, 0644); err != nil {
+		return err
+	} else {
+		defer userfd.Close()
+		if pxeTmpl, err := template.New("pxeUser").Parse(string(pxeTplCnt)); err != nil {
+			return err
+		} else if err := pxeTmpl.Execute(userfd, map[string]string{"username": username}); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func init() {
+	log.Println(RegisterUserMAC(net.IPv4(192, 168, 23, 21), "mercie_d"))
+}