CODEWITHSUNDEEP
bashshellopenssl
djechlin
djechlin

Reputation: 60768

openssl pass first few lines from script then read from stdin

I want to run openssl and have it begin with the following commands sent to the server:

t authenticate <dynamically generated base64 string from calling script>
t select Inbox

Then from there take input from stdin. I'm very ignorant in shell scripting and the openssl toolkit, and I certainly don't see how to do this simply with piping / redirecting stdin unless perhaps I tried setting up a file that was simultaneously drawing from stdin itself, or such.

I'm not exactly sure the technologies openssl uses to read its input. For example the following:

$ echo "t login [email protected] password" | openssl s_client -connect imap.mail.yahoo.com:993

Does not do the same thing as

openssl s_client -connect imap.mail.yahoo.com:993
# openssl dialogue opens...
C: t login [email protected] password
S: t NO [AUTHENTICATIONFAILED] Incorrect username or password. (#YSH002)

I imagine openssl is opening a new shell session (I'm weak in my understanding here) and it does not pass its arguments from stdin to the inner shell it creates.

Upvotes: 0

Views: 5999

Answers (5)

jeremy mordkoff
jeremy mordkoff

Reputation: 59

None of these solutions return control of stdin to the user. This should pass first command and second command to openssl and then read stdin: 

cat <<EOF - | openssl ....
first command
second command
EOF

Upvotes: 2

Egor
Egor

Reputation: 11

I'd like to add that you can use Nick's solution as one-line script:

$ sh -c 'echo "first command"; echo "second command"; while read x; do  echo "$x"; done' | whatever

Upvotes: 1

Nick
Nick

Reputation: 2050

I'd recommend splitting the problem into two scripts:

Firstly you have one script that echoes the initial commands that you want to send and then reads from stdin and writes to stdout. Like this (call it script1.sh for instance):

#!/bin/bash
echo "first command"
echo "second command"
while read x
do
  echo "$x"
done

The second script then just bundles the arguments to openssl so you don't have to keep typing them (call this script2.sh for instance. Note that as with script1.sh above, you should have the #!/bin/bash on the first line to tell the OS that it's a bash script.

then you can just type:

script1.sh | script2.sh

and you'll get the first two lines passed to openssl and then everything you type will get passed after that. If you want to always finish with a few commands you can add them after the while loop in script1.sh.

You terminate the whole thing with Ctrl-D

If openssl echoes the input you type then you will get the lines you type in shown twice (which is a bit irritating). In that case the "-s" argument to "read" will suppress the first line (useful for typing passwords for instance)

Note that this solution is similar to the solution suggested earlier with the temporary file and the tail -f but it avoids the need for a temporary file and everything is done in a single line.

The problem with the solution given in the question is that stdin to the openssl command is closed when the 'echo "t login ..."' command finishes and this will generally cause programs to exit. With the solution given here the pipe connects the stdout of the first script to the stdin of the second and everything typed into read will get passed on to openssl

Upvotes: 2

jweyrich
jweyrich

Reputation: 32240

You can change your script to write the commands to a file, and then use tee -a to redirect stdin to that same file. Let me show you an example:

jweyrich@pharao:~$ echo "command1" > cmds
jweyrich@pharao:~$ tee -a cmds > /dev/null
command2
command3
^C

In the mean time, I was running tail -f cmds in another tty:

jweyrich@pharao:~$ tail -f cmds 
command1
command2
command3

This will turn that file into the single source you have to read and process.

Upvotes: 1

Volker Stolz
Volker Stolz

Reputation: 7402

The basic SSL/TLS connection to an SSL-enabled IMAP server can be established through s_client:

openssl s_client -connect imapserver.example.com:143 -starttls imap

Note the trailing -starttls imap: openssl "knows" how to tell the IMAP server that it would like to move from the plain-text connection (as you would get with telnet) to the SSL-secured.

After this, openssl's job is done, and you need to speak proper IMAP to the server, including authentification!

Upvotes: 1

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