How to su in a script if su needs a pswd ?

[Aman]

Hello,

I am running a command as part of my script on a Unix box for which I need
to su to a different username.

This su requires a password as well.

I could not find any option of passing the password in su.

Tried the shell script solution of here docs :

su <<TillEnd
admin
test
TillEnd

But even this does not work.

Could anyone please guide me how to su in a script (shell / perl) ?

I cannot have my username added to the /etc/sudoers to execute commands as
root...

Thanks in advance
-aman

[James]

> Hello, 

Take a look at the Expect module. Here is some code from a script i did a
long time ago. It was a wrapper script for su. It may help:
--
use strict;
use Expect;
use IO:Socket;

# grab the user if entered
my $user = $ARGV[0] if $ARGV[0];
my $pw;

# might fail if it's su -
if ($user && $user !~ /root/) {
real_su();
}
# &real_su unless $user =~ /root/;

print "Password: ";
$pw = <STDIN>;
chomp $pw;

# send the captured password to be cyphered
cypher($pw);

# tunnel($string);

# now that we cypher and sent the pw to us go ahead and run the

&real_su();


sub real_su
{

my $su = Expect->spawn('/bin/su',$user) or die "Can't start Program:
$!\n";
# stop the output from going to STDOUT
$su->log_stdout(0);
# capture pw and die with appropriate string if pw is wrong
my $error = ($su->expect(10, 'password:'))[1];
if ($error)
{
print $su "Sorry.\r";
print STDOUT "Sorry.\r";
$su->soft_close();
}
print $su "$pw\r";
$su->soft_close();
exit 0;
}

........

[Randal]

>>>>> "Aman" == Aman Thind <co.in> writes:

Aman> I am running a command as part of my script on a Unix box for which I need
Aman> to su to a different username.

Aman> This su requires a password as well.

A question just like this was posted to the Perl-Beginners Yahoo
mailing list.

If this was you, your question was already asked and answered,
and should not be re-asked in a different forum. You're wasting
valuable resources.

If it wasn't you, please look at the archives, located at
<http://groups.yahoo.com/group/perl-beginner/messages>, and search for
the subject lines similar to what you asked here.

--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<com> <URL:http://www.stonehenge.com/merlyn/>
Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!

[Wiggins]

> 

Can you 'setuid' the script that needs to be called with the special
privileges? Then shell out to that script for the processing it needs
to do...

I am not much of a setuid expert but this should work based on my
understanding of it.

http://danconia.org

[Aman]

Hi James,

Thanks for the pointer to the Expect module.

I'll set it up and hope I get it working...else I'll come running back to
you :p

Can I establish an SSH connection and do something like Sshexec and Scp
tasks do in ant 1.6.x using Expect ?

Thanks
-aman

-----Original Message-----
From: Kipp, James [mailto:com]
Sent: 17 February 2004 19:35
To: 'Thind, Aman'; Perl Beginners
Subject: RE: How to su in a script if su needs a pswd ?

 

Take a look at the Expect module. Here is some code from a script i did a
long time ago. It was a wrapper script for su. It may help:
--
use strict;
use Expect;
use IO:Socket;

# grab the user if entered
my $user = $ARGV[0] if $ARGV[0];
my $pw;

# might fail if it's su -
if ($user && $user !~ /root/) {
real_su();
}
# &real_su unless $user =~ /root/;

print "Password: ";
$pw = <STDIN>;
chomp $pw;

# send the captured password to be cyphered
cypher($pw);

# tunnel($string);

# now that we cypher and sent the pw to us go ahead and run the

&real_su();


sub real_su
{

my $su = Expect->spawn('/bin/su',$user) or die "Can't start Program:
$!\n";
# stop the output from going to STDOUT
$su->log_stdout(0);
# capture pw and die with appropriate string if pw is wrong
my $error = ($su->expect(10, 'password:'))[1];
if ($error)
{
print $su "Sorry.\r";
print STDOUT "Sorry.\r";
$su->soft_close();
}
print $su "$pw\r";
$su->soft_close();
exit 0;
}

........

[Aman]

Hello Randal,

In your -

If ( aman eq "same person who asked in a diff forum")
{
print "JERK";
}
Else
{
print "Valuable archive of answers to similar question" ;
}

I pass through the else block as you had earlier answered to one Joe
Catanzaro though his question was strikingly similar to mine.

One of the most valuable resources that I would be wasting by asking the
same question in diff forums for which I've already received the answer is
my own time !

Thanks for the link though...the discussion was enlightening indeed.

-aman

-----Original Message-----
From: com [mailto:com]
Sent: 17 February 2004 20:30
To: org
Subject: Re: How to su in a script if su needs a pswd ?

 [/ref][/ref]

Aman> I am running a command as part of my script on a Unix box for which I
need
Aman> to su to a different username.

Aman> This su requires a password as well.

A question just like this was posted to the Perl-Beginners Yahoo
mailing list.

If this was you, your question was already asked and answered,
and should not be re-asked in a different forum. You're wasting
valuable resources.

If it wasn't you, please look at the archives, located at
<http://groups.yahoo.com/group/perl-beginner/messages>, and search for
the subject lines similar to what you asked here.

--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<com> <URL:http://www.stonehenge.com/merlyn/>
Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl
training!

--
To unsubscribe, e-mail: org
For additional commands, e-mail: org
<http://learn.perl.org/> <http://learn.perl.org/first-response>

[Randal]

>>>>> "Aman" == Thind, Aman <co.in> writes:

Aman> I pass through the else block as you had earlier answered to one Joe
Aman> Catanzaro though his question was strikingly similar to mine.

I just find it odd that nobody asks a question like that for at least
six months in my recollection, and then it pops up twice within two
days in two different similar forums. So shoot me. :)

More often than not, it's someone who is interested in wasting a lot
of free resources.

--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<com> <URL:http://www.stonehenge.com/merlyn/>
Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!

[Aman]

:)
By the way your stress on avoiding to store the pswd in any readable disk
file really made me look at my problem and possible solutions from a whole
new perspective...

Cheers !
-aman

-----Original Message-----
From: com [mailto:com]
Sent: 17 February 2004 21:53
To: Thind, Aman
Cc: org
Subject: Re: How to su in a script if su needs a pswd ?

 [/ref][/ref]

Aman> I pass through the else block as you had earlier answered to one Joe
Aman> Catanzaro though his question was strikingly similar to mine.

I just find it odd that nobody asks a question like that for at least
six months in my recollection, and then it pops up twice within two
days in two different similar forums. So shoot me. :)

More often than not, it's someone who is interested in wasting a lot
of free resources.

--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<com> <URL:http://www.stonehenge.com/merlyn/>
Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl
training!

[Wiggins]

Please bottom post....
 

You could, but in the case of SSH you would be better off using
Net::SSH::Perl or Net::SFTP. Expect should be an absolute last resort,
screen scraping is fine when there is no other published interface, in
the case of SSH that isn't the case.

http://danconia.org
 
>
> Take a look at the Expect module. Here is some code from a script i did a
> long time ago. It was a wrapper script for su. It may help:
> --
> use strict;
> use Expect;
> use IO:Socket;
>
> # grab the user if entered
> my $user = $ARGV[0] if $ARGV[0];
> my $pw;
>
> # might fail if it's su -
> if ($user && $user !~ /root/) {
> real_su();
> }
> # &real_su unless $user =~ /root/;
>
> print "Password: ";
> $pw = <STDIN>;
> chomp $pw;
>
> # send the captured password to be cyphered
> cypher($pw);
>
> # tunnel($string);
>
> # now that we cypher and sent the pw to us go ahead and run the
>
> &real_su();
>
>
> sub real_su
> {
>
> my $su = Expect->spawn('/bin/su',$user) or die "Can't start Program:
> $!\n";
> # stop the output from going to STDOUT
> $su->log_stdout(0);
> # capture pw and die with appropriate string if pw is wrong
> my $error = ($su->expect(10, 'password:'))[1];
> if ($error)
> {
> print $su "Sorry.\r";
> print STDOUT "Sorry.\r";
> $su->soft_close();
> }
> print $su "$pw\r";
> $su->soft_close();
> exit 0;
> }
>
> .......
>
>
>
> --
> To unsubscribe, e-mail: org
> For additional commands, e-mail: org
> <http://learn.perl.org/> <http://learn.perl.org/first-response>
>
>
>[/ref]