HELP Please

gemini728 · 09-27-2003, 10:35 AM

I am a Lunx newbie. My system is Redhat v9.0. Yesterday, I updated my system using the Redhat Network up2date app. Now I cannot login. I am positive I am using my correct password for root, but the system keeps giving me the message "Authentication Failed".

Any ideas? I vaguely remember hearing that there is a standalone account that can be used to bypass the standard login in cases where a user forgets his/her password. Maybe that would work? If so, can anyone tell me what that login is?

The only other alternative I can think of is to reformat the drive and start all over again. I have quite a bit of data and software downloads, as well as configuration, that I would prefer not to lose.

Thanks to anyone who can help.

david_ross · 09-27-2003, 10:49 AM

Welcome to LQ.

Follow these steps to reset your root password:
1) Reboot your computer.
2) When the grub bootloader appears on the screen select the entry for your linux system - it may be the only one.
3) Press the "e" key to edit the entry.
4) Select the line beggining with "kernel".
5) Press the "e" key again
6) Type " single" no quotes
7) Press enter
8) Press "b" to boot
9) When the prompt appears type "passwd" press enter
10) Enter a new password when prompted
11) Reboot by typing "shutdown -r now"

gemini728 · 09-27-2003, 11:13 AM

Thank you David, but I could not get the instructions to work. Here is what happens:

I follow the instructions and after I fullfill step #8, the system begins to boot and then it says "kernel panic: no init found. try passing init= option to the kernel"

I tried various combinations of passing the word "single" to the argument list, including init=single, but none worked. Is my system a lost cause?

david_ross · 09-27-2003, 01:16 PM

did you make sure it was a space then single?

gemini728 · 09-27-2003, 02:46 PM

David, thank you for your help. Yes, you are right, I had not noticed the space before the word "single". After I entered it properly, it let me change the root password, which I did. However, when I rebooted after that, it still gave me the message "authentication failed", I know I must have done something wrong, I just wish I knew what. If you happen to think of any other ideas, I would be very grateful.

Even of you cannot help me any further, I want to thank you for all your help - you have been very friendly and extremely helpful, unlike another Linux website - justlinux.com. When I posted the identical request for help on their forum, the moderator deleted my thread because, he said, I did not follow his protocol (I used the word "Help" in the subject line - apparently this is a very serious problem on his forum.) Anyway, it is nice to have a friendly person who is more interested in providing help than the words used to request help.

Thank you, and if you can think of some other ideas, I would appreciate it very much.

david_ross · 09-27-2003, 02:49 PM

What packages did you upgrade?

gemini728 · 09-27-2003, 02:52 PM

I ran the Up2date app and it connected to the Redhat network for the files to update. I do not recall which files were updated (there were quite a few), but I think the kernel was part of those. I also had installed some additional apps from the Linux CD - I think I added a couple of more text editors and some multimedia related apps.

david_ross · 09-27-2003, 03:02 PM

Perhaps you could try following the procedure above until step 9 then make copies of:
/etc/passwd
/etc/shadow
/etc/group

Then create new files with just root entries:
/etc/passwd=
root:x:0:0:root:/root:/bin/bash
/etc/shadow=
root::12178:0:99999:7:::
/etc/group=
root:x:0:root

Make sure the permissions are set with:
chmod 644 /etc/shadow /etc/group /etc/passwd
chown root:root /etc/shadow /etc/group /etc/passwd

Then perform the reboot (step 11) after that login with user "root" and no password (just press enter at the prompt)

gemini728 · 09-27-2003, 03:09 PM

David,

I just changed the root password again and then rather than reboot, I thought I would try loging in right from the command prompt, since I was already there. When it prompted me for the user I entered "root" and at the password prompt I entered the new password to which I had changed the system. It gave me the following message:

"Authentication service cannot retrieve authentication info"

I do not know whether this gives you a better idea of what might be wrong.

To my untrained mind it almost seems as though the password file might be corrupt (it cannot store passwords). Is there perhaps a way for me to delete and recreate the password file? Will that even help?

When I changed the password at the prompt, it said that all authentication tokens had been updated.

Thanks again.

gemini728 · 09-27-2003, 03:11 PM

Sorry, looks like our posts crossed. I am about to try your latest suggestion...

gemini728 · 09-27-2003, 04:06 PM

David,

I just struggled with the Linux command line and I think I deleted and created the 3 files correctly. At least they appeared there when I did an "ls" listing. First I copied the original files into an _old version. Then I used "vi" to create a new version of each file with the text you provided. Since I am still not familiar with Linux, I hope I did it correctly. Anyway, after rebooting it gave me the login prompt and I entered "root". But it never gave me a password prompt, it just went back to a login prompt.

What do you think? Did I do something wrong with the 3 files?

david_ross · 09-28-2003, 07:47 AM

When you do:
ls -l /etc/passwd /etc/shadow /etc/group

Does it show:

Code:

-rw-r--r--    1 root     root          899 Sep 27 16:30 /etc/group
-rw-r--r--    1 root     root         2645 Aug 24 11:47 /etc/passwd
-r--------    1 root     root         1840 Aug 24 11:47 /etc/shadow

If not then change the permissions to match.

gemini728 · 09-28-2003, 08:33 AM

David,

The /etc/shadow did not have the permissions you showed. The other 2 files were OK. I changed the /etc/shadow to -r--------. Then I rebooted.

Now they look like this:

-rw-r--r-- 1 root root 15 Sep 27 17:00 group
-rw-r--r-- 1 root root 32 Sep 27 16:58 passwd
-r-------- 1 root root 26 Sep 27 17:22 shadow

When I get the prmopt:

52 login:

I type "root" and the same thing happens as before - no password prompt, instead it just goes right back to the login prompt.

david_ross · 09-28-2003, 08:47 AM

There should be an up2date logfile:
/var/log/up2date

Perhaps there will be a bit more information as to what has changed there.

You may want to put the password fiels back now too.

gemini728 · 09-28-2003, 09:38 AM

David,

I looked at the up2date log files, but I am afraid I cannot tell much from them. I did not see anything that stands out as an obvious error.

I wish to thank you for all your help. Obviously I must have done something to the system that will not allow me to login. I doubt Redhat did anything wrong with their up2date system. Even though I could not get back in (the system appears to run just fine, it is just that I cannot login), I learned a lot from your help and trying to get back in. I have made carefull notes of everything you told me and I will keep them for future reference. I did not expect to get such a crash course on the Linux command line. Thanks again.

Incidentally, should you think of anything that might help, please let me know. I will most likely wait a couple of days and then reinstall Linux.

I hope I was not too much of a bother.