belier

Christoph Berg

Sometimes remote accounts are only reachable with a series of ssh/su/sudo commands. Using ProxyCommands in .ssh/config works for simple cases, but not with several hops, or if passwords have to be entered.

The belier tool takes as input a series of user@hostname strings and will produce an expect script that does the actual login work.

$ cat input
user@host1 root pw1
user2@host2 pw2

$ bel -e input

$ cat host2.sh
#!/usr/bin/expect -f
set timeout 10

spawn ssh -o NoHostAuthenticationForLocalhost=yes -o StrictHostKeyChecking=no  user@host1
expect -re  "(%|#|\\$) $"
send -- "su - root\r"
expect ":"
send -- "pw1\r"
expect -re  "(%|#|\\$) $"
send -- "ssh -o NoHostAuthenticationForLocalhost=yes -o StrictHostKeyChecking=no  user2@host2\r"
expect -re {@[^\n]*:}
send -- "pw2\r"
expect -re  "(%|#|\\$) $"
interact +++ return

The generated host2.sh script uses ugly ssh options, but is easily edited.

Now I need the same thing for scp…

Update: Carl Chenet, belier’s author, kindly pointed me to the documentation which has examples how belier can set up ssh tunnels to copy files.