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Thread: always get "Authentication Failure" and sudo password fails

  1. #1
    Join Date
    Apr 2009
    Beans
    19

    always get "Authentication Failure" and sudo password fails

    Installed 9.10 (from the same DVD) on two different systems here, same issue.

    I created a user, say it's "foo", on the initial install. When I set it to log in automatically it works fine but "sudo <cmd>" prompts for the password and it always fails after "[sudo] password for foo:" as if I am typing in the wrong password (I am not).

    If I try and log out and log back in, it won't do the graphical login, says "Authentication Failure".

    I have reinstalled about half a dozen times across two different systems, figuring I must have really typoed the password when installing and therefore I must be typing in a wrong password. But after doing this over, and over, and over, it seems clear that I am not actually typing in the wrong password. It's just broken.

    Same thing for the GUI synaptic update manager (tells me there are updates available, I try and update, it asks for the password, then tells me "Authentication Failure").

    Incidentally, if I do "passwd" and change it from the shell, if I type the [correct] password, then try and change it to the current password, it says "Password Unchanged". So clearly somewhere something knows the right password.

    This is a huge PITA since you can't do a freakin' thing on Ubuntu without sudo working.

    So what am I doing wrong, or what can I do differently to make this work?

  2. #2
    Join Date
    Oct 2005
    Location
    Jacksonville, FL
    Beans
    29,420

    Re: always get "Authentication Failure" and sudo password fails

    Do you belong to group adm? You need to belong to group adm to use sudo.

    Code:
    id
    In the world of Linux, who needs Windows and Gates...

    Got most of my golden beans at an auction on eBay (with a couple of free drinks).

  3. #3
    Join Date
    Apr 2009
    Beans
    19

    Re: always get "Authentication Failure" and sudo password fails

    yep! it's the one and only user account, and it belongs to the group "adm".

    "...groups=4(adm)..."

  4. #4
    Join Date
    Feb 2007
    Location
    Romania
    Beans
    Hidden!
    Distro
    Ubuntu Development Release

    Re: always get "Authentication Failure" and sudo password fails

    Actually you have to belong to the admin group.

    Can you use policykit to authenticate yourself as an admin?
    If so, what's in the sudoers file?

    Code:
    pkexec cat /etc/sudoers

  5. #5
    Join Date
    Apr 2009
    Beans
    19

    Re: always get "Authentication Failure" and sudo password fails

    When I do that, I get "Authentication is needed to run '/bin/cat' as the super user" and "Authentication Failure".

    also a part of the "admin" group:

    "...115(admin)..."
    Last edited by mr72; December 30th, 2009 at 10:40 PM.

  6. #6
    Join Date
    Feb 2007
    Location
    Romania
    Beans
    Hidden!
    Distro
    Ubuntu Development Release

    Re: always get "Authentication Failure" and sudo password fails

    Is your user in the admin group?

    Did you check the data integrity of the DVD?
    community/HowToMD5SUM

    What keyboard layout are you using? Did you change it after installation?

    Can you use the su command to authenticate yourself?
    Code:
    su username

  7. #7
    Join Date
    Apr 2009
    Beans
    19

    Re: always get "Authentication Failure" and sudo password fails

    Quote Originally Posted by sisco311 View Post
    Is your user in the admin group?

    Did you check the data integrity of the DVD?
    community/HowToMD5SUM

    What keyboard layout are you using? Did you change it after installation?

    Can you use the su command to authenticate yourself?
    Code:
    su username
    No, that says:

    * No device configured for user "username".
    Password: <type correect password>
    su: Authentication Failure

    I didn't do a md5sum on the DVD image.
    I am about to dl a new 9.10 CD and install it again.
    KB layout is USA, buy default. I didn't change it.

    this is turning out to be a royal pain.

  8. #8
    Join Date
    Apr 2007
    Beans
    37

    Re: always get "Authentication Failure" and sudo password fails

    I have this exact same problem with all versions of 9.04 and above. The cd's md5 is correct. It works on all pcs in my house except for one. Any solution?

  9. #9
    Join Date
    May 2010
    Beans
    13

    Re: always get "Authentication Failure" and sudo password fails

    No cure sorry to say, but same issue... upgraded from 8.04 to 10.04 via Update Manager -> Upgrade... after restart couldn't log in... tried re-installing from Live CD, same result "authentication failure" over and over... There has to be a fix out there somewhere... I'm trying to do all this via long distance support to my mother (who, bless her, at nearly 80 is not a command line kinda' gal)... help!?!

    J

  10. #10
    Join Date
    Apr 2007
    Beans
    37

    Re: always get "Authentication Failure" and sudo password fails

    The last version that works on my PC is 8.10. All versions from 9.04 and up have this problem. What has changed in the way of authentication between these releases? There has to be a way to get this obscure problem resolved.

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