diff options
| -rw-r--r-- | challenge/c36.go | 67 | ||||
| -rw-r--r-- | lib/srp.go | 3 |
2 files changed, 67 insertions, 3 deletions
diff --git a/challenge/c36.go b/challenge/c36.go index 80c231a..67c4f1e 100644 --- a/challenge/c36.go +++ b/challenge/c36.go @@ -13,8 +13,6 @@ import ( "ricketyspace.net/cryptopals/lib" ) -// Usage: -// func C36(args []string) { if len(args) < 2 { fmt.Println("Usage: cryptopals -c 36 [ client | server ] PORT") @@ -102,13 +100,27 @@ func C36(args []string) { } hmac := []byte(cpacket[:len(cpacket)-1]) if !user.SessionKeyMacVerify(hmac) { - return fmt.Errorf("hmac verification: %v", hmac) + return fmt.Errorf("hmac verification failed") } // Login user. user.LogIn() return nil } + // Logout user on the server. + serverLogoutUser := func(server *lib.SRPServer, ident string, + conn net.Conn) error { + user, err := server.GetUser(ident) + if err != nil { + return fmt.Errorf("get user: %v", err) + } + if !user.LoggedIn() { + return fmt.Errorf("user not logged in") + } + // Logout user. + user.LogOut() + return nil + } // Handle connection from a client. serverHandleConn := func(server *lib.SRPServer, conn net.Conn) { defer conn.Close() @@ -149,6 +161,14 @@ func C36(args []string) { fmt.Fprintf(conn, "OK\n") } return + case parts[0] == "logout": + err = serverLogoutUser(server, parts[1], conn) + if err != nil { + fmt.Fprintf(conn, "%v\n", err) + } else { + fmt.Fprintf(conn, "OK\n") + } + return default: fmt.Fprintf(conn, "invalid action") return @@ -335,6 +355,40 @@ func C36(args []string) { client.LogIn() return nil } + // Logout user. + clientLogoutUser := func(client *lib.SRPClient) error { + // Make logout packet. + packet := fmt.Sprintf("%s+%s", "logout", client.Ident()) + + // Try to connect to server. + conn, err := net.Dial("tcp", fmt.Sprintf(":%d", port)) + if err != nil { + return fmt.Errorf("unable connect to server: %v", err) + } + defer conn.Close() + + // Send login packet to server. + _, err = fmt.Fprintf(conn, "%s\n", packet) + if err != nil { + return fmt.Errorf("logout send: %v", err) + } + + // Wait and try to get logout ACK from server. + spacket, err := bufio.NewReader(conn).ReadString('\n') + if err != nil { + return fmt.Errorf("logout recv: %v", err) + } + // Remove newline character. + spacket = spacket[:len(spacket)-1] + if spacket != "OK" { + return fmt.Errorf("logout ack: %s", spacket) + } + + // Logout user. + client.Session = nil + + return nil + } // Start SRP client. clientSpawn := func() { client := new(lib.SRPClient) @@ -368,6 +422,13 @@ func C36(args []string) { } else { fmt.Printf("Logged in!\n") } + case client.LoggedIn() && msg_parts[0] == "logout": + err := clientLogoutUser(client) + if err != nil { + fmt.Printf("Logout failed: %v\n", err) + } else { + fmt.Printf("Logged out!\n") + } } } } @@ -259,6 +259,9 @@ func (u *SRPUser) LogIn() { } func (u *SRPUser) LogOut() { + u.b = nil // Reset secret ephemeral value + u.u = nil // Reset scrambling parameter. + u.sk = []byte{} // Reset session key u.loggedIn = false } |