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token-validator: done many challenges

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This commit is contained in:
nemunaire 2018-02-20 18:20:07 +01:00 committed by Pierre-Olivier Mercier
parent 91edced44d
commit 133244897b
4 changed files with 313 additions and 8 deletions
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253
token-validator/challenge.go Normal file
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@ -0,0 +1,253 @@
package main
import (
"crypto/hmac"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"log"
"net/http"
"strconv"
"strings"
"time"
"github.com/julienschmidt/httprouter"
"golang.org/x/crypto/blake2b"
)
const IPgwDMZ = "172.23.200.1"
type Challenge struct {
Accessible []func(*Student, *http.Request) error
Check func(*Student, *givenToken, int) error
}
/* Restrictions */
func noAccessRestriction(*Student, *http.Request) error {
return nil
}
func accessFrom(ip string) func(_ *Student, r *http.Request) error {
return func(_ *Student, r *http.Request) error {
if r.Header.Get("X-Forwarded-By") != ip {
return errors.New("This challenge is not accessible this way.")
}
return nil
}
}
func notAccessFrom(ip string) func(_ *Student, r *http.Request) error {
return func(_ *Student, r *http.Request) error {
if r.Header.Get("X-Forwarded-By") == ip {
return errors.New("This challenge is not accessible this way.")
}
return nil
}
}
func maxProxy(nb int) func(_ *Student, r *http.Request) error {
return func(_ *Student, r *http.Request) error {
if len(strings.Split(r.Header.Get("X-Forwarded-For"), ",")) > nb {
return errors.New("This challenge is not accessible this way.")
}
return nil
}
}
func sslOnly(_ *Student, r *http.Request) error {
if r.Header.Get("X-Forwarded-Proto") != "https" {
return errors.New("This challenge should be performed over TLS.")
}
return nil
}
/* Challenges */
func challenge42(s *Student, t *givenToken, chid int) error {
pkey := s.GetPKey()
if expectedToken, err := GenerateToken(pkey, chid, []byte("42")); err != nil {
return err
} else if ! hmac.Equal(expectedToken, t.token) {
return errors.New("This is not the expected token.")
} else {
return nil
}
}
func challengeDNS(s *Student, t *givenToken, chid int) error {
pkey := s.GetPKey()
if expectedToken, err := GenerateToken(pkey, chid, []byte("8dde678132d6c558fc6adaeb9f1d53bf6ec7b876308cf98c48604caa9138523c1ce58b672c87c7e7d9b7248b81804d3940dbf20bf263eeb683244f7c1143712d")); err != nil {
return err
} else if ! hmac.Equal(expectedToken, t.token) {
return errors.New("This is not the expected token.")
} else {
return nil
}
}
func challengeTime(s *Student, t *givenToken, chid int) error {
pkey := s.GetPKey()
if expectedToken, err := GenerateToken(pkey, chid, []byte(t.Data[0])); err != nil {
return err
} else if ! hmac.Equal(expectedToken, t.token) {
return errors.New("This is not the expected token.")
} else if t, err := strconv.ParseInt(t.Data[0], 10, 64); err != nil {
return err
} else {
var rt time.Time
if t > 3000000000 {
rt = time.Unix(t / 1000000000, t % 1000000000)
} else {
rt = time.Unix(t, 0)
}
if rt.After(time.Now()) {
return errors.New("You seem to live in the future...")
} else if d := rt.Sub(time.Now()); d.Minutes() < -10 {
return errors.New(fmt.Sprintf("Your time is %.0f minutes from us", d.Minutes()))
}
return nil
}
}
func challengeDisk(s *Student, t *givenToken, chid int) error {
pkey := s.GetPKey()
n1, err := strconv.Atoi(t.Token[0:2])
if err != nil {
return err
}
n2, err := strconv.Atoi(t.Token[2:4])
if err != nil {
return err
}
sum := make([]byte, hex.DecodedLen(len(t.Token[4:])))
if _, err := hex.Decode(t.token, []byte(t.Token[4:])); err != nil {
return err
}
expectedToken := blake2b.Sum512([]byte(pkey[n1:n2]))
if ! hmac.Equal(expectedToken[:], sum) {
return errors.New("This is not the expected token.")
} else {
return nil
}
}
var challenges []Challenge
func init() {
challenges = []Challenge{
/* Challenge 1 : 42 */
Challenge{
Accessible: []func(*Student, *http.Request) error{noAccessRestriction},
Check: challenge42,
},
/* Challenge 2 : 42 from DMZ */
Challenge{
Accessible: []func(*Student, *http.Request) error{accessFrom(IPgwDMZ)},
Check: challenge42,
},
/* Challenge 3 : ssl (+ ntp) */
Challenge{
Accessible: []func(*Student, *http.Request) error{accessFrom(IPgwDMZ), sslOnly},
Check: challengeTime,
},
/* Challenge 4 : disk */
Challenge{
Accessible: []func(*Student, *http.Request) error{noAccessRestriction},
Check: challengeDisk,
},
/* Challenge 5 : DNS TXT */
Challenge{
Accessible: []func(*Student, *http.Request) error{accessFrom(IPgwDMZ), sslOnly},
Check: challengeDNS,
},
/* Challenge 6 : time net */
Challenge{
Accessible: []func(*Student, *http.Request) error{maxProxy(1)},
Check: challengeTime,
},
}
router.GET("/challenge", apiHandler(getChallengeList))
router.GET("/challenge/:chid", rawHandler(accessibleChallenge))
router.POST("/challenge", rawHandler(receiveToken))
}
type givenToken struct {
Login string `json:"login"`
Challenge int `json:"challenge"`
Token string `json:"token"`
token []byte
Data []string `json:"data"`
}
func getChallengeList(_ httprouter.Params, _ []byte) (interface{}, error) {
var ret []int
for i := range challenges {
ret = append(ret, i)
}
return ret, nil
}
func accessibleChallenge(r *http.Request, ps httprouter.Params, _ []byte) (interface{}, error) {
if chid, err := strconv.Atoi(string(ps.ByName("chid"))); err != nil {
return nil, err
} else if chid == 0 || chid >= len(challenges) {
return nil, errors.New("This challenge doesn't exist")
} else {
for _, a := range challenges[chid - 1].Accessible {
if err := a(nil, r); err != nil {
return nil, err
}
}
return true, nil
}
}
func receiveToken(r *http.Request, ps httprouter.Params, body []byte) (interface{}, error) {
if _, err := accessibleChallenge(r, ps, body); err != nil {
return nil, err
}
var gt givenToken
if err := json.Unmarshal(body, &gt); err != nil {
return nil, err
}
gt.token = make([]byte, hex.DecodedLen(len(gt.Token)))
if _, err := hex.Decode(gt.token, []byte(gt.Token)); err != nil {
return nil, err
}
if chid, err := strconv.Atoi(string(ps.ByName("chid"))); err != nil {
return nil, err
} else if chid == 0 || chid > len(challenges) {
return nil, errors.New("This challenge doesn't exist")
} else if std, err := getStudentByLogin(gt.Login); err != nil {
return nil, err
} else {
if err := challenges[chid - 1].Check(&std, &gt, chid); err != nil {
log.Printf("%s just try ch#%d: %s\n", std.Login, chid, err)
return nil, err
}
if _, err := std.UnlockNewChallenge(chid, gt.Token); err != nil {
log.Println(err)
return nil, err
}
log.Printf("%s just unlock ch#%d\n", std.Login, chid)
return "Success", nil
}
}

8
token-validator/handler.go
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@ -38,7 +38,7 @@ func remoteValidatorHandler(f func(http.ResponseWriter, *http.Request, httproute
}
}
func apiHandler(f DispatchFunction) func(http.ResponseWriter, *http.Request, httprouter.Params) {
func rawHandler(f func(*http.Request, httprouter.Params, []byte) (interface{}, error)) func(http.ResponseWriter, *http.Request, httprouter.Params) {
return func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
if addr := r.Header.Get("X-Forwarded-For"); addr != "" {
r.RemoteAddr = addr
@ -69,7 +69,7 @@ func apiHandler(f DispatchFunction) func(http.ResponseWriter, *http.Request, htt
}
}
ret, err = f(ps, body)
ret, err = f(r, ps, body)
// Format response
resStatus := http.StatusOK
@ -99,6 +99,10 @@ func apiHandler(f DispatchFunction) func(http.ResponseWriter, *http.Request, htt
}
}
func apiHandler(f DispatchFunction) func(http.ResponseWriter, *http.Request, httprouter.Params) {
return rawHandler(func (_ *http.Request, ps httprouter.Params, b []byte) (interface{}, error) { return f(ps, b) })
}
func studentHandler(f func(Student, []byte) (interface{}, error)) func(httprouter.Params, []byte) (interface{}, error) {
return func(ps httprouter.Params, body []byte) (interface{}, error) {
if sid, err := strconv.Atoi(string(ps.ByName("sid"))); err != nil {

36
token-validator/students.go
View File

@ -1,6 +1,8 @@
package main
import (
"crypto/hmac"
"crypto/sha512"
"encoding/json"
"strings"
"time"
@ -10,19 +12,21 @@ import (
func init() {
router.GET("/api/students/", apiHandler(
func(httprouter.Params,[]byte) (interface{}, error) {
return getStudents() }))
func(httprouter.Params, []byte) (interface{}, error) {
return getStudents()
}))
router.POST("/api/students/", remoteValidatorHandler(apiHandler(createStudent)))
router.GET("/api/students/:sid/", apiHandler(studentHandler(
func(std Student, _ []byte) (interface{}, error) {
return std, nil })))
return std, nil
})))
router.PUT("/api/students/:sid/", remoteValidatorHandler(apiHandler(studentHandler(updateStudent))))
router.DELETE("/api/students/:sid/", remoteValidatorHandler(apiHandler(studentHandler(
func(std Student, _ []byte) (interface{}, error) {
return std.Delete() }))))
return std.Delete()
}))))
}
type Student struct {
Id int64 `json:"id"`
Login string `json:"login"`
@ -70,6 +74,10 @@ func NewStudent(login string) (Student, error) {
}
}
func (s Student) GetPKey() []byte {
return hmac.New(sha512.New512_224, []byte(sharedSecret)).Sum([]byte(s.Login))
}
func (s Student) Update() (int64, error) {
if res, err := DBExec("UPDATE students SET login = ?, time = ? WHERE id_student = ?", s.Login, s.Time, s.Id); err != nil {
return 0, err
@ -100,7 +108,6 @@ func ClearStudents() (int64, error) {
}
}
func createStudent(_ httprouter.Params, body []byte) (interface{}, error) {
var std Student
if err := json.Unmarshal(body, &std); err != nil {
@ -120,3 +127,20 @@ func updateStudent(current Student, body []byte) (interface{}, error) {
current.Time = new.Time
return current.Update()
}
type UnlockedChallenge struct {
Id int64 `json:"id"`
IdStudent int64 `json:"id_student"`
Challenge int `json:"challenge"`
Time time.Time `json:"time"`
}
func (s Student) UnlockNewChallenge(challenge int, value string) (UnlockedChallenge, error) {
if res, err := DBExec("INSERT INTO student_challenges (id_student, challenge, time, value) VALUES (?, ?, ?, ?)", s.Id, challenge, time.Now(), value); err != nil {
return UnlockedChallenge{}, err
} else if utid, err := res.LastInsertId(); err != nil {
return UnlockedChallenge{}, err
} else {
return UnlockedChallenge{utid, s.Id, challenge, time.Now()}, err
}
}

24
token-validator/token.go Normal file
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@ -0,0 +1,24 @@
package main
import (
"fmt"
"golang.org/x/crypto/blake2b"
)
func GenerateToken(pkey []byte, id int, a... []byte) ([]byte, error) {
h, err := blake2b.New(blake2b.Size, nil)
if err != nil {
return nil, err
}
h.Write(pkey)
h.Write([]byte(fmt.Sprintf(":%d", id)))
for _, v := range a {
h.Write([]byte(":"))
h.Write(v)
}
return h.Sum(nil), nil
}