package redis import ( "crypto/aes" "crypto/cipher" "crypto/rand" "encoding/base64" "encoding/hex" "fmt" "io" "net/http" "strings" "time" "github.com/go-redis/redis" "github.com/pusher/oauth2_proxy/cookie" "github.com/pusher/oauth2_proxy/pkg/apis/options" "github.com/pusher/oauth2_proxy/pkg/apis/sessions" "github.com/pusher/oauth2_proxy/pkg/cookies" ) // TicketData is a structure representing the ticket used in server session storage type TicketData struct { TicketID string Secret []byte } // SessionStore is an implementation of the sessions.SessionStore // interface that stores sessions in redis type SessionStore struct { CookieCipher *cookie.Cipher CookieOptions *options.CookieOptions Client *redis.Client } // NewRedisSessionStore initialises a new instance of the SessionStore from // the configuration given func NewRedisSessionStore(opts *options.SessionOptions, cookieOpts *options.CookieOptions) (sessions.SessionStore, error) { client, err := newRedisClient(opts.RedisStoreOptions) if err != nil { return nil, fmt.Errorf("error constructing redis client: %v", err) } rs := &SessionStore{ Client: client, CookieCipher: opts.Cipher, CookieOptions: cookieOpts, } return rs, nil } func newRedisClient(opts options.RedisStoreOptions) (*redis.Client, error) { if opts.UseSentinel { client := redis.NewFailoverClient(&redis.FailoverOptions{ MasterName: opts.SentinelMasterName, SentinelAddrs: opts.SentinelConnectionURLs, }) return client, nil } opt, err := redis.ParseURL(opts.RedisConnectionURL) if err != nil { return nil, fmt.Errorf("unable to parse redis url: %s", err) } client := redis.NewClient(opt) return client, nil } // Save takes a sessions.SessionState and stores the information from it // to redies, and adds a new ticket cookie on the HTTP response writer func (store *SessionStore) Save(rw http.ResponseWriter, req *http.Request, s *sessions.SessionState) error { if s.CreatedAt.IsZero() { s.CreatedAt = time.Now() } // Old sessions that we are refreshing would have a request cookie // New sessions don't, so we ignore the error. storeValue will check requestCookie requestCookie, _ := req.Cookie(store.CookieOptions.CookieName) value, err := s.EncodeSessionState(store.CookieCipher) if err != nil { return err } ticketString, err := store.storeValue(value, store.CookieOptions.CookieExpire, requestCookie) if err != nil { return err } ticketCookie := store.makeCookie( req, ticketString, store.CookieOptions.CookieExpire, s.CreatedAt, ) http.SetCookie(rw, ticketCookie) return nil } // Load reads sessions.SessionState information from a ticket // cookie within the HTTP request object func (store *SessionStore) Load(req *http.Request) (*sessions.SessionState, error) { requestCookie, err := req.Cookie(store.CookieOptions.CookieName) if err != nil { return nil, fmt.Errorf("error loading session: %s", err) } val, _, ok := cookie.Validate(requestCookie, store.CookieOptions.CookieSecret, store.CookieOptions.CookieExpire) if !ok { return nil, fmt.Errorf("Cookie Signature not valid") } session, err := store.loadSessionFromString(val) if err != nil { return nil, fmt.Errorf("error loading session: %s", err) } return session, nil } // loadSessionFromString loads the session based on the ticket value func (store *SessionStore) loadSessionFromString(value string) (*sessions.SessionState, error) { ticket, err := decodeTicket(store.CookieOptions.CookieName, value) if err != nil { return nil, err } result, err := store.Client.Get(ticket.asHandle(store.CookieOptions.CookieName)).Result() if err != nil { return nil, err } resultBytes := []byte(result) block, err := aes.NewCipher(ticket.Secret) if err != nil { return nil, err } // Use secret as the IV too, because each entry has it's own key stream := cipher.NewCFBDecrypter(block, ticket.Secret) stream.XORKeyStream(resultBytes, resultBytes) session, err := sessions.DecodeSessionState(string(resultBytes), store.CookieCipher) if err != nil { return nil, err } return session, nil } // Clear clears any saved session information for a given ticket cookie // from redis, and then clears the session func (store *SessionStore) Clear(rw http.ResponseWriter, req *http.Request) error { requestCookie, _ := req.Cookie(store.CookieOptions.CookieName) val, _, ok := cookie.Validate(requestCookie, store.CookieOptions.CookieSecret, store.CookieOptions.CookieExpire) if !ok { return fmt.Errorf("Cookie Signature not valid") } // We go ahead and clear the cookie first, always. clearCookie := store.makeCookie( req, "", time.Hour*-1, time.Now(), ) http.SetCookie(rw, clearCookie) // We only return an error if we had an issue with redis // If there's an issue decoding the ticket, ignore it ticket, _ := decodeTicket(store.CookieOptions.CookieName, val) if ticket != nil { _, err := store.Client.Del(ticket.asHandle(store.CookieOptions.CookieName)).Result() if err != nil { return fmt.Errorf("error clearing cookie from redis: %s", err) } } return nil } // makeCookie makes a cookie, signing the value if present func (store *SessionStore) makeCookie(req *http.Request, value string, expires time.Duration, now time.Time) *http.Cookie { if value != "" { value = cookie.SignedValue(store.CookieOptions.CookieSecret, store.CookieOptions.CookieName, value, now) } return cookies.MakeCookieFromOptions( req, store.CookieOptions.CookieName, value, store.CookieOptions, expires, now, ) } func (store *SessionStore) storeValue(value string, expiration time.Duration, requestCookie *http.Cookie) (string, error) { ticket, err := store.getTicket(requestCookie) if err != nil { return "", fmt.Errorf("error getting ticket: %v", err) } ciphertext := make([]byte, len(value)) block, err := aes.NewCipher(ticket.Secret) if err != nil { return "", fmt.Errorf("error initiating cipher block %s", err) } // Use secret as the Initialization Vector too, because each entry has it's own key stream := cipher.NewCFBEncrypter(block, ticket.Secret) stream.XORKeyStream(ciphertext, []byte(value)) handle := ticket.asHandle(store.CookieOptions.CookieName) err = store.Client.Set(handle, ciphertext, expiration).Err() if err != nil { return "", err } return ticket.encodeTicket(store.CookieOptions.CookieName), nil } // getTicket retrieves an existing ticket from the cookie if present, // or creates a new ticket func (store *SessionStore) getTicket(requestCookie *http.Cookie) (*TicketData, error) { if requestCookie == nil { return newTicket() } // An existing cookie exists, try to retrieve the ticket val, _, ok := cookie.Validate(requestCookie, store.CookieOptions.CookieSecret, store.CookieOptions.CookieExpire) if !ok { // Cookie is invalid, create a new ticket return newTicket() } // Valid cookie, decode the ticket return decodeTicket(store.CookieOptions.CookieName, val) } func newTicket() (*TicketData, error) { rawID := make([]byte, 16) if _, err := io.ReadFull(rand.Reader, rawID); err != nil { return nil, fmt.Errorf("failed to create new ticket ID %s", err) } // ticketID is hex encoded ticketID := fmt.Sprintf("%x", rawID) secret := make([]byte, aes.BlockSize) if _, err := io.ReadFull(rand.Reader, secret); err != nil { return nil, fmt.Errorf("failed to create initialization vector %s", err) } ticket := &TicketData{ TicketID: ticketID, Secret: secret, } return ticket, nil } func (ticket *TicketData) asHandle(prefix string) string { return fmt.Sprintf("%s-%s", prefix, ticket.TicketID) } func decodeTicket(cookieName string, ticketString string) (*TicketData, error) { prefix := cookieName + "-" if !strings.HasPrefix(ticketString, prefix) { return nil, fmt.Errorf("failed to decode ticket handle") } trimmedTicket := strings.TrimPrefix(ticketString, prefix) ticketParts := strings.Split(trimmedTicket, ".") if len(ticketParts) != 2 { return nil, fmt.Errorf("failed to decode ticket") } ticketID, secretBase64 := ticketParts[0], ticketParts[1] // ticketID must be a hexadecimal string _, err := hex.DecodeString(ticketID) if err != nil { return nil, fmt.Errorf("server ticket failed sanity checks") } secret, err := base64.RawURLEncoding.DecodeString(secretBase64) if err != nil { return nil, fmt.Errorf("failed to decode initialization vector %s", err) } ticketData := &TicketData{ TicketID: ticketID, Secret: secret, } return ticketData, nil } func (ticket *TicketData) encodeTicket(prefix string) string { handle := ticket.asHandle(prefix) ticketString := handle + "." + base64.RawURLEncoding.EncodeToString(ticket.Secret) return ticketString }