Files
sxchnge/backend/edge/shared/auth/browser/browser.go
T

122 lines
3.0 KiB
Go

package browser
import (
"net/http"
"net/url"
"os"
"path"
"strings"
"time"
"git.sendico.io/tech/sxchnge/bff/pkg/merrors"
)
const (
TransportHeader = "X-Auth-Transport"
TransportCookie = "cookie"
CSRFHeader = "X-CSRF-Protection"
CSRFValue = "1"
RefreshCookie = "sxchnge_refresh"
)
func UsesCookie(r *http.Request) bool {
return r != nil && strings.EqualFold(strings.TrimSpace(r.Header.Get(TransportHeader)), TransportCookie)
}
func RefreshCredential(r *http.Request, fallback string) (string, error) {
if !UsesCookie(r) {
return strings.TrimSpace(fallback), nil
}
cookie, err := r.Cookie(RefreshCookie)
if err != nil || strings.TrimSpace(cookie.Value) == "" {
return "", merrors.Unauthorized("browser session is missing")
}
return cookie.Value, nil
}
func SetRefreshCookie(w http.ResponseWriter, r *http.Request, token string, expiresAt time.Time) {
if !UsesCookie(r) {
return
}
maxAge := int(time.Until(expiresAt).Seconds())
if maxAge < 1 {
maxAge = 1
}
http.SetCookie(w, &http.Cookie{
Name: RefreshCookie,
Value: token,
Path: cookiePath(r),
Expires: expiresAt.UTC(),
MaxAge: maxAge,
HttpOnly: true,
Secure: true,
SameSite: http.SameSiteStrictMode,
})
}
func ClearRefreshCookie(w http.ResponseWriter, r *http.Request) {
if !UsesCookie(r) {
return
}
http.SetCookie(w, &http.Cookie{
Name: RefreshCookie,
Value: "",
Path: cookiePath(r),
Expires: time.Unix(1, 0).UTC(),
MaxAge: -1,
HttpOnly: true,
Secure: true,
SameSite: http.SameSiteStrictMode,
})
}
func ValidateCSRF(r *http.Request, allowedOrigins []string) error {
if !UsesCookie(r) || isSafeMethod(r.Method) {
return nil
}
if r.Header.Get(CSRFHeader) != CSRFValue {
return merrors.PermissionDenied("browser CSRF protection header is missing")
}
origin := strings.TrimSpace(r.Header.Get("Origin"))
if origin == "" || !originAllowed(origin, allowedOrigins) {
return merrors.PermissionDenied("browser request origin is not allowed")
}
return nil
}
func cookiePath(r *http.Request) string {
const accountsSegment = "/accounts"
if apiEndpoint := strings.TrimSpace(os.Getenv("API_ENDPOINT")); apiEndpoint != "" {
return path.Join("/", apiEndpoint, accountsSegment)
}
if r != nil && r.URL != nil {
if index := strings.Index(r.URL.Path, accountsSegment); index >= 0 {
return r.URL.Path[:index+len(accountsSegment)]
}
}
return accountsSegment
}
func isSafeMethod(method string) bool {
switch method {
case http.MethodGet, http.MethodHead, http.MethodOptions, http.MethodTrace:
return true
default:
return false
}
}
func originAllowed(origin string, allowedOrigins []string) bool {
parsed, err := url.Parse(origin)
if err != nil || parsed.Scheme == "" || parsed.Host == "" || parsed.User != nil || parsed.Path != "" {
return false
}
normalized := strings.TrimSuffix(strings.ToLower(origin), "/")
for _, allowed := range allowedOrigins {
if strings.TrimSuffix(strings.ToLower(strings.TrimSpace(allowed)), "/") == normalized {
return true
}
}
return false
}