Python's Paramiko gets stuck sometimes when verifying credentials - log file stuck at [chan 0] Unhandled channel request "[email protected]"

Question

I'm using the Paramiko Python module to connect to a remote server as user admin and then switch user to root.

here is the class I'm using

class ShellHandler:

    def __init__(self, host, user, psw):
        self.ssh = paramiko.SSHClient()
        self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        self.ssh.connect(host, username=user, password=psw, port=22)

        channel = self.ssh.invoke_shell()
        self.stdin = channel.makefile('wb')
        self.stdout = channel.makefile('r')
        self.shell = channel

    def __del__(self):
        self.ssh.close()

    def ftp(self):
        ftp_client = self.ssh.open_sftp()
        return ftp_client

    def execute(self, cmd):
        """

        :param cmd: the command to be executed on the remote computer
        :examples:  execute('ls')
                    execute('finger')
                    execute('cd folder_name')
        """
        cmd = cmd.strip('\n')
        self.stdin.write(cmd + '\n')
        finish = 'end of stdOUT buffer. finished with exit status'
        echo_cmd = 'echo {} $?'.format(finish)
        self.stdin.write(echo_cmd + '\n')
        shin = self.stdin
        self.stdin.flush()

        shout = []
        sherr = []
        exit_status = 0
        for line in self.stdout:
            if str(line).startswith("FINISHED"): # add "; echo FINISHED" to the end of commands that take much longer to excute
                break
            if str(line).startswith(cmd) or str(line).startswith(echo_cmd):
                # up for now filled with shell junk from stdin
                shout = []
            elif str(line).startswith(finish):
                # our finish command ends with the exit status
                exit_status = int(str(line).rsplit(maxsplit=1)[1])
                if exit_status:
                    # stderr is combined with stdout.
                    # thus, swap sherr with shout in a case of failure.
                    sherr = shout
                    shout = []
                break
            else:
                # get rid of 'coloring and formatting' special characters
                shout.append(re.compile(r'(\x9B|\x1B\[)[0-?]*[ -/]*[@-~]').sub('', line).
                             replace('\b', '').replace('\r', ''))

        # first and last lines of shout/sherr contain a prompt
        if shout and echo_cmd in shout[-1]:
            shout.pop()
        if shout and cmd in shout[0]:
            shout.pop(0)
        if sherr and echo_cmd in sherr[-1]:
            sherr.pop()
        if sherr and cmd in sherr[0]:
            sherr.pop(0)

        return shin, shout, sherr

here is my code to connect to the server

# grab IP / admin password
while True:
    ip_address = input("Enter Hostname/IP address for Server: ")
    if len(ip_address) > 0:
        break
    else:
        continue
while True:
    admin_pw = getpass.getpass("Enter password for user admin: ")
    if len(admin_pw) > 0:
        break
    else:
        continue
#verify IP / admin password
try:
    logging.info("initiate ssh connection to {}".format(ip_address))
    server = ShellHandler(ip_address, "admin", admin_pw)
    print("Connected to {} as user admin".format(ip_address))
    logging.info("Connected to {} as user admin".format(ip_address))
except Exception as e:
    logging.exception("Exception occurred")
    sys.exit("Incorrect IP/Password")
#grab and verify root password
while True:
    root_pw = getpass.getpass("Enter password for user root: ")
    if len(root_pw) == 0:
        continue
    try:
        logging.info("verify root password")
        keystrokes = server.shell
        logging.info("invoke shell")
        keystrokes.send("su root\n")
        logging.info("switch user")
        keystrokes.send("{}\n".format(root_pw))
        logging.info("root password was send via channel")
        cmd = server.execute("whoami")
        logging.info("who am i")
        logging.info("cmd output {}".format(cmd))
        if "root\n" in cmd[1]:
            print("Connected to {} as user root".format(ip_address))
            logging.info("Connected to {} as user root".format(ip_address))
            break
        else:
            logging.info("Incorrect Password")
            print("Incorrect Password")
            continue
    except Exception as e:
        logging.exception("Exception occurred")
        print("Incorrect Password")
        continue

the code works 90% of the time without any problems, but sometimes it gets stuck at the root password part - right after you enter the root password and hit enter, here is what that looks like on the console

when I check the log file, this is what I find:

2022-04-15 09:09:23,062 - INFO - Connected to *********** as user admin
2022-04-15 09:09:26,855 - INFO - verify root password
2022-04-15 09:09:26,855 - INFO - invoke shell
2022-04-15 09:09:26,855 - INFO - switch user
2022-04-15 09:09:26,856 - INFO - root password was send via channel
2022-04-15 09:09:43,080 - DEBUG - [chan 0] Unhandled channel request "[email protected]"
2022-04-15 09:09:58,441 - DEBUG - [chan 0] Unhandled channel request "[email protected]"
2022-04-15 09:10:13,801 - DEBUG - [chan 0] Unhandled channel request "[email protected]"

it gets stuck at this line forever and it never times out.

my question is, what do I change to make this part timeout if it gets stuck, and allow the user to enter root password again. without having to terminate the program and run it again.