Trying to send passwrod via expect script in sshfs

Question

I have server that has 2fa and does not allow login using ssh keys. I want to connect via FTP, I am using sshfs. Normal sshfs user@host:/remote/ /local/ works fine. But I wanted to pass the passwrod using expect (-o password_stdin does not work for me).

I have defined the function in .bashrc

function mount_sshfs_with_2fa() {

  # Get the FTP password from the encrypted file
  local password=$(gpg --decrypt encrypted_password.txt)

  # Prompt for verification code
  read -p "Verification code: " otp
  echo $otp

  expect << EOF
    spawn sshfs user@host:/remote/ /local/
    expect -re "code:"
    send -- "$otp\r"
    send_user "Verification code: $otp\n"
    expect -re "Password:"
    send -- "$password\r"
    send_user "Password: $password\n"

EOF
}

It does not give any error but does not mount either. Please tell me what's wrong.

debug

expect -d gives

Verification code: 325776
325776
expect version 5.45.4
argv[0] = expect  argv[1] = -d  
set argc 0
set argv0 "expect"
set argv ""
executing commands from command file
spawn sshfs user@host:/remote/ /local/
parent: waiting for sync byte
parent: telling child to go ahead
parent: now unsynchronized from child
spawn: returns {153497}

expect: does "" (spawn_id exp4) match glob pattern "code:"? no
Verification code: 
expect: does "\rVerification code: " (spawn_id exp4) match glob pattern "code:"? yes
expect: set expect_out(0,string) "code:"
expect: set expect_out(spawn_id) "exp4"
expect: set expect_out(buffer) "\rVerification code:"
send: sending "325776\r" to { exp4 }

expect: does " " (spawn_id exp4) match glob pattern "assword:"? no


expect: does " \r\n" (spawn_id exp4) match glob pattern "assword:"? no
Password: 
expect: does " \r\n\rPassword: " (spawn_id exp4) match glob pattern "assword:"? yes
expect: set expect_out(0,string) "assword:"
expect: set expect_out(spawn_id) "exp4"
expect: set expect_out(buffer) " \r\n\rPassword:"
send: sending "(my password)\r" to { exp4 }

update 2 Instead of here-code the following also does not work

expect -c "
    spawn sshfs user@host:/remote/ /local/
    expect "code:"
    send -- "$otp\r"
    expect "assword:"
    send -- "$password\r"
    interact
  "

Is expect something serious or just time waste? I have seen multiple solutions that worked for others gave me error! For example, interact does not work inside expect here-code?

Answer 1

Most probably it's killed by SIGHUP. Try like this:

expect << EOF
    spawn -ignore SIGHUP sshfs user@host:/remote/ /local/

    set timeout -1

    expect -re "code:"
    send -- "$otp\r"
    expect -re "Password:"
    send -- "$password\r"

    expect eof
    sleep 1
EOF

Answer 2

One thing to note: when the heredoc ends (at EOF), then the expect process exits, and the sshfs process will be killed.

You need to keep expect running, and you probably want to launch it in the background:

function mount_sshfs_with_2fa() {

  # Get the FTP password from the encrypted file
  local password=$(gpg --decrypt encrypted_password.txt)

  # Prompt for verification code
  read -p "Verification code: " otp

  {
    expect << EOF
      spawn sshfs user@host:/remote/ /local/
      expect -re {Verification code: $}
      send -- "$otp\r"
      expect -re {Password: $}
      send -- "$password\r"
      set timeout -1
      expect eof
EOF
  } &
}