68 lines
1.6 KiB
Go
68 lines
1.6 KiB
Go
package main
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import (
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"crypto/hmac"
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"crypto/sha256"
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"crypto/subtle"
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"encoding/base64"
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"encoding/json"
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"net/http"
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"strings"
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"time"
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)
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const sessionCookieName = "telesrv_admin_session"
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type sessionClaims struct {
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Actor string `json:"actor"`
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Exp int64 `json:"exp"`
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Nonce string `json:"nonce"`
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}
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func signSession(key []byte, claims sessionClaims) (string, error) {
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payload, err := json.Marshal(claims)
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if err != nil {
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return "", err
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}
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encPayload := base64.RawURLEncoding.EncodeToString(payload)
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mac := hmac.New(sha256.New, key)
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mac.Write([]byte(encPayload))
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sig := base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
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return encPayload + "." + sig, nil
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}
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func verifySession(key []byte, value string, now time.Time) (sessionClaims, bool) {
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parts := strings.Split(value, ".")
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if len(parts) != 2 {
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return sessionClaims{}, false
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}
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mac := hmac.New(sha256.New, key)
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mac.Write([]byte(parts[0]))
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want := base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
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if subtle.ConstantTimeCompare([]byte(parts[1]), []byte(want)) != 1 {
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return sessionClaims{}, false
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}
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payload, err := base64.RawURLEncoding.DecodeString(parts[0])
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if err != nil {
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return sessionClaims{}, false
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}
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var claims sessionClaims
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if err := json.Unmarshal(payload, &claims); err != nil {
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return sessionClaims{}, false
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}
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if claims.Actor == "" || claims.Exp <= now.Unix() {
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return sessionClaims{}, false
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}
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return claims, true
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}
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func clearSessionCookie(w http.ResponseWriter) {
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http.SetCookie(w, &http.Cookie{
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Name: sessionCookieName,
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Value: "",
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Path: "/",
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MaxAge: -1,
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HttpOnly: true,
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SameSite: http.SameSiteLaxMode,
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})
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}
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