[SOLVED] password code

anil007523 · 07-29-2010, 07:14 AM

hi...
well i am new to linux programming. can any one give the code for password.
that means when we enter password it has to check it with root password and return the value.
i'm working on security for files. If we leave the system open any one can see the contents of it.so i want to write a system call for security to files.It will ask the password for all the files.And i'm not a cracker or a professional programmer.This is my mini project and has to submit it very soon so plz help me soon
please help me out from this from last 2 months i'm trying.
thank you in advance.

Aquarius_Girl · 07-29-2010, 07:19 AM

Quote:

Originally Posted by anil007523

hi...
well i am new to linux programming. can any one give the code for password.
that means when we enter password it has to check it with root password and return the value.

IMO you can find the root password only through /etc directory which itself requires a root password.

and I find this thread suspicious.

djsmiley2k · 07-29-2010, 07:21 AM

Your going to need to explain more about what exactly your trying to achieve.

It SOUNDS like your trying to build a password cracker, but that wont work if you can't access the place the hashes of the passwords are stored (which is passworded...).

If its something else then maybe we can assist...

pixellany · 07-29-2010, 07:54 AM

It does not matter whether you are root or not. Even if you can read /etc/shadow, you will not be able to de-crypt the encrypted passwords.

Please post more information on what exactly you need to do, and why. It sounds like homework, but no responsible teacher is going to give out assignments on how to retrieve passwords.

Aquarius_Girl · 07-29-2010, 07:57 AM

Quote:

Originally Posted by pixellany

It does not matter whether you are root or not. Even if you can read /etc/shadow,

What did you mean by this ? One can't read even the /etc files.

Code:

anisha@linux-uitj:~> cat /etc/shadow
cat: /etc/shadow: Permission denied

djsmiley2k · 07-29-2010, 07:59 AM

Quote:

Originally Posted by pixellany

Please post more information on what exactly you need to do, and why. It sounds like homework, but no responsible teacher is going to give out assignments on how to retrieve passwords.

Why not, isn't part of learning about security learning how to break into something?

Of course it has to come with lessions about the ethical implications of what your doing, or might use it for.

anil007523 - Please don't edit your original post for additions, instead post a new post so we can see what you've added - makes following the convo alot easier.

djsmiley2k · 07-29-2010, 08:02 AM

Quote:

Originally Posted by anishakaul

What did you mean by this ? One can't read even the /etc files.

Code:

anisha@linux-uitj:~> cat /etc/shadow
cat: /etc/shadow: Permission denied

You've just proven what pixellany said, You can't access files, even if the workstation is unlocked you've got no access beyond that of the user your logged in as.

UNLESS you left it logged in as root, but this is idiotic and if someone did this then there is no security which would protect them (other than the fact the content of some files is encrypted.)

Aquarius_Girl · 07-29-2010, 08:14 AM

Quote:

Originally Posted by djsmiley2k

You've just proven what pixellany said, You can't access files, even if the workstation is unlocked you've got no access beyond that of the user your logged in as.

UNLESS you left it logged in as root, but this is idiotic and if someone did this then there is no security which would protect them (other than the fact the content of some files is encrypted.)

Pixel said "Even if you can read /etc/shadow,...", so my question was since through cat command I can't see the shadow file, then how can I read or Decrypt it ?

though I don't understand "workstation is unlocked"

pixellany · 07-29-2010, 08:16 AM

Quote:

Originally Posted by djsmiley2k

Why not, isn't part of learning about security learning how to break into something?

You have a good point.

djsmiley2k · 07-29-2010, 08:16 AM

Quote:

Originally Posted by anishakaul

Pixel said "Even if you can read /etc/shadow,...", so my question was since through cat command I can't see the shadow file, then how can I read or Decrypt it ?

though I don't understand "workstation is unlocked"

Only root can read that file. You must be logged in as root to see the content (which is then encrypted as well).

By unlocked, I mean someone has left it logged in and not secured it after using it.

--------------

Slightly offtopic - Is this for your disseration at university? The fact you've been working on it for two months, and want it so soon makes me feel that it maybe. If so your going to have to define the problem your trying to fix more clearly as I dont see exactly what your trying to prove.

pixellany · 07-29-2010, 08:21 AM

root can read (and write) ALL files or--if necessary--can change the permissions to enable it.

But--if I am not mistaken--NO-ONE can decrypt the entries in /etc/shadow.

Aquarius_Girl · 07-30-2010, 12:50 AM

Quote:

Originally Posted by pixellany

But--if I am not mistaken--NO-ONE can decrypt the entries in /etc/shadow.

If even root can't do so, does it mean that I can't get my old password back if I have lost it ?

pixellany · 07-30-2010, 08:43 AM

Quote:

Originally Posted by anishakaul

If even root can't do so, does it mean that I can't get my old password back if I have lost it ?

Correct.

Aquarius_Girl · 07-30-2010, 11:25 AM

Quote:

Originally Posted by pixellany

Correct.

Alright I can safely conclude now that no one can ever write a program for finding the root password or any other password in Linux.

anil007523 · 07-30-2010, 12:06 PM

Thank you for the information.