72 lines
1.4 KiB
Go
72 lines
1.4 KiB
Go
package auth
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import (
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"crypto/rand"
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"crypto/subtle"
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"encoding/hex"
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"net/http"
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"strings"
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"sync"
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)
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type Manager struct {
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mu sync.RWMutex
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token string
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}
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func NewManager(token string) *Manager { return &Manager{token: token} }
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func (m *Manager) Token() string { m.mu.RLock(); defer m.mu.RUnlock(); return m.token }
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func (m *Manager) Rotate() string {
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b := make([]byte, 24)
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if _, err := rand.Read(b); err != nil {
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panic(err)
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}
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t := hex.EncodeToString(b)
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m.mu.Lock()
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m.token = t
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m.mu.Unlock()
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return t
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}
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type Middleware struct {
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Token string
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Manager *Manager
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Optional bool
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}
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func (m Middleware) Handler(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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got := ""
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h := r.Header.Get("Authorization")
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if strings.HasPrefix(h, "Bearer ") {
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got = strings.TrimSpace(strings.TrimPrefix(h, "Bearer "))
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}
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expected := m.Token
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if m.Manager != nil {
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expected = m.Manager.Token()
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}
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if got == "" && m.Optional {
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next.ServeHTTP(w, r)
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return
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}
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if expected == "" || got == "" || subtle.ConstantTimeCompare([]byte(got), []byte(expected)) != 1 {
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unauthorized(w)
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return
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}
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next.ServeHTTP(w, r)
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})
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}
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func unauthorized(w http.ResponseWriter) {
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w.Header().Set("Content-Type", "application/json")
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w.Header().Set("WWW-Authenticate", "Bearer realm=\"vps-commander\"")
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w.WriteHeader(http.StatusUnauthorized)
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_, _ = w.Write([]byte("{\"error\":\"Unauthorized\"}"))
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}
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