163 lines
4.5 KiB
Go
163 lines
4.5 KiB
Go
package main
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import (
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"bytes"
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"crypto/hmac"
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"crypto/sha512"
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"encoding/base64"
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"encoding/json"
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"errors"
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"fmt"
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"log"
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"net"
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"net/http"
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"strings"
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"time"
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)
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var loginSalt string
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type loginChecker struct {
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students []Student
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authMethod AuthMethod
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}
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type loginUpload struct {
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Username string
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Password string
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}
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func (l loginChecker) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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if addr := r.Header.Get("X-Forwarded-For"); addr != "" {
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r.RemoteAddr = addr
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}
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log.Printf("%s \"%s %s\" [%s]\n", r.RemoteAddr, r.Method, r.URL.Path, r.UserAgent())
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w.Header().Set("Content-Type", "text/plain")
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// Check request type and size
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if r.Method != "POST" {
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http.Error(w,
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"Invalid request",
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http.StatusBadRequest)
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return
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} else if r.ContentLength < 0 || r.ContentLength > 1023 {
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http.Error(w,
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"Request entity too large",
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http.StatusRequestEntityTooLarge)
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return
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}
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dec := json.NewDecoder(r.Body)
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var lu loginUpload
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if err := dec.Decode(&lu); err != nil {
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http.Error(w,
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err.Error(),
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http.StatusBadRequest)
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return
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}
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// Perform login check
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canContinue := false
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for _, std := range l.students {
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if std.Login == lu.Username {
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canContinue = true
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}
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}
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if !canContinue {
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log.Println("Login not found:", lu.Username, "at", r.RemoteAddr)
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http.Error(w, "Login not found in whitelist.", http.StatusUnauthorized)
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return
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}
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if ok, err := l.authMethod.checkAuth(lu.Username, lu.Password); err != nil {
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log.Println("Unable to perform authentication for", lu.Username, ":", err, "at", r.RemoteAddr)
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http.Error(w, err.Error(), http.StatusUnauthorized)
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return
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} else if !ok {
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log.Println("Login failed:", lu.Username, "at", r.RemoteAddr)
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http.Error(w, "Invalid password", http.StatusUnauthorized)
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return
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}
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// Find corresponding MAC
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var ip net.IP
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spl := strings.SplitN(r.RemoteAddr, ":", 2)
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if ip = net.ParseIP(spl[0]); ip == nil {
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http.Error(w, "Unable to parse given IPv4: " + spl[0], http.StatusInternalServerError)
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return
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}
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var mac *ARPEntry
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if tab, err := ARPAnalyze(); err != nil {
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log.Println("Error on ARPAnalyze:", err)
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http.Error(w, "Internal server error. Please retry in a few minutes", http.StatusInternalServerError)
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return
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} else {
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mac = ARPContainsIP(tab, ip)
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}
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if mac == nil {
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log.Printf("Unable to find MAC address for given IP (%s)\n", ip)
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http.Error(w, "Internal server error. Please retry in a few minutes", http.StatusInternalServerError)
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return
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}
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// Register the user remotely
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if ip, err := l.registerUser(lu.Username, r.RemoteAddr, *mac); err != nil {
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log.Println("Error on remote registration for", lu.Username, ":", err)
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http.Error(w, "Internal server error. Please retry in a few minutes", http.StatusInternalServerError)
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return
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} else if err := l.lateLoginAction(lu.Username, r.RemoteAddr, *mac, ip); err != nil {
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log.Println("Error on late login action for", lu.Username, ":", err)
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http.Error(w, "Internal server error. Please retry in a few minutes", http.StatusInternalServerError)
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return
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} else {
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log.Println("Successful login of", lu.Username, "at", r.RemoteAddr)
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http.Error(w, fmt.Sprintf("Use the following IP: %s", ip), http.StatusOK)
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}
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}
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type myIP struct {
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Id int64 `json:"id"`
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Login string `json:"login"`
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IP string `json:"ip"`
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}
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func (l loginChecker) registerUser(username, remoteAddr string, ent ARPEntry) (net.IP, error) {
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bts, err := json.Marshal(map[string]interface{}{"login": username, "ip": remoteAddr, "mac": fmt.Sprintf("%02x:%02x:%02x:%02x:%02x:%02x", ent.HWAddress[0], ent.HWAddress[1], ent.HWAddress[2], ent.HWAddress[3], ent.HWAddress[4], ent.HWAddress[5])})
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if err != nil {
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return nil, nil
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}
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req, err := http.NewRequest("POST", "https://adlin.nemunai.re/api/students/", bytes.NewReader(bts))
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if err != nil {
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return nil, err
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}
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req.Header.Add("X-ADLIN-Authentication", base64.StdEncoding.EncodeToString(hmac.New(sha512.New, []byte(loginSalt)).Sum([]byte(fmt.Sprintf("%d", time.Now().Unix()/10)))))
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req.Header.Set("Content-Type", "application/json")
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client := &http.Client{}
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resp, err := client.Do(req)
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if err != nil {
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return nil, err
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return nil, errors.New(resp.Status)
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} else {
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dec := json.NewDecoder(resp.Body)
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var myip myIP
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if err := dec.Decode(&myip); err != nil {
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return nil, err
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}
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return net.ParseIP(myip.IP), nil
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}
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}
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func (l loginChecker) lateLoginAction(username, remoteAddr string, mac ARPEntry, ip net.IP) error {
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return RegisterUserMAC(mac, ip, username)
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}
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