topic Re: Shell question (rexec) in Operating System - HP-UX

Shell question (rexec)

Sebastien Huber — Tue, 30 Oct 2001 16:26:09 GMT

Hi, i would like in a shell to automate a remote execution by using rexec (not remsh!)
But did not find any solution to authenticate myself ; here is the tests i made :

srvA>rexec srvB -l logB pwd << !
`echo $pass`
!
-> then i'm asked for the password

srvA>echo $pass | rexec srvB -l logB pwd
-> idem

Any idea ?

Re: Shell question (rexec)

Craig Rants — Tue, 30 Oct 2001 16:30:00 GMT

Does svrb have a .rhosts entry for svra?

I would recommend installing Secure Shell and using that to perform trusted remote execution type commands.

Hope this helps.

Re: Shell question (rexec)

Uday_S_Ankolekar — Tue, 30 Oct 2001 16:33:06 GMT

Hello,

.rhosts is the file that should take care of your problem

-USA..

Re: Shell question (rexec)

Sebastien Huber — Tue, 30 Oct 2001 16:36:15 GMT

Thanks for this suggestion, but i've never tried to install secure shell, can u give me more information to do this ?

Re: Shell question (rexec)

Darrell Allen — Tue, 30 Oct 2001 16:36:18 GMT

From the man page of rexec:

The rexec command works the same as remsh except that it uses the rexec() library routine and rexecd for command execution (see rexec(3N) and rexecd(1M)) and does not support Kerberos authentication. rexec prompts for a password before executing the command instead of using hosts.equiv for authentication. It should be used in instances where a password to a remote account is known but there are insufficient permissions for remsh.

Think you'll have to use a password with rexec.

Darrell

Re: Shell question (rexec)

Sebastien Huber — Wed, 31 Oct 2001 14:20:22 GMT

Ok, i think i don't have given enough informations, here they are :
1) i want to perform a remote shell execution
2) i do not want to use a .rhosts file, users have to authenticate themselves
3) i do not want user to be able to show the password by using the ps command

Any idea ?

Re: Shell question (rexec)

Craig Rants — Wed, 31 Oct 2001 14:31:44 GMT

Have you looked at using expect? This newsgroup posting may help.

I'm using the following unix expect script to interact the Oracle
sqlplus utility. Sqlplus prompts for a password, expect sends the password,
then I 'interact'. Most of the time this works, but every once in a
while, the password shows on the screen, and expect just sits there
waiting for something, and doesn't make it to interact. If I put in a
'sleep 1', I don't have this problem, but am not sure why. Any
pointers? I'd like to (1) avoid the delay if possible, and (2) insure
that the password never shows even with the 'sleep', but without knowing
what's happening, I'm not confident that 'sleep 1' will always work.

#!/usr/local/bin/expect --
set usern "testuser"
set passw [exec aprogramtogetpassword $usern]
set timeout -1
eval spawn sqlplus $usern
log_user 0
expect "Enter password: "
# why do I need the following sleep?:
sleep 1
send "$passw\r"
log_user 1
expect {
"Enter user-name: " exit
"Connected"
}
interact

Re: Shell question (rexec)

Craig Rants — Wed, 31 Oct 2001 14:47:17 GMT

Huber,
The easiest way to install ssh is to get the depots from the hpux porting site.

http://hpux.connect.org.uk/

get openssh, openssl, and zlib

Either make them a depot, or install seperately with openssh being the last install because of dependencies. I'll attach my notes for installation and setting up a trust based on keys

Of course hostnames and domains have been changed to protect the guilty

Re: Shell question (rexec)

Joseph A Benaiah_1 — Sun, 11 Nov 2001 18:01:16 GMT

Huber,

Sorry that I did not see you request earlier. With HP-UX, you can write a C program to carry out rexec commands without having to enter the password.

Compile it using the HP bundles C compiler by typing cc remex.c -o remex.

For use:

remex myhost "/sbin/ioscan -ufnCdisk" -q

It is quite secure as the way that I encode the password into it means that srunning a strings on the binary will not revel the password.

Re: Shell question (rexec)

Joseph A Benaiah_1 — Sun, 11 Nov 2001 18:07:04 GMT

Huber,

I seem to have problems attaching the source code in the forum area.

Lets try again.

Re: Shell question (rexec)

harry d brown jr — Sun, 11 Nov 2001 20:34:51 GMT

Huber,

This thread, although covering telnet, covers the same. You need expect, tcl, and tk:

http://forums.itrc.hp.com/cm/QuestionAnswer/1,11866,0x54e2c6af36b7d5118ff10090279cd0f9,00.html

live free or die
harry